TABLE OF CONTENTS PAGE INTRODUCTION AND ACKNOWLEDGMENTS……………………………. 1 2002 POTATO BREEDING AND GENETICS RESEARCH REPORT 2002 POTATO VARIETY EVALUATIONS David S. Douches, J. Coombs, K. Zarka, Susannah Copper, L. Frank, J. Driscoll and E. Estelle………………………………………… 5 D. S. Douches, J. Coombs, L. Frank, J. Driscoll, K. Zarka, C. Long, R. Hammerschmidt, and W. Kirk……………………..….……… 20 2002 ON-FARM POTATO VARIETY TRIALS Chris Long, Dr. Dave Douches, Dr. Dick Chase, Don Smucker (Montcalm), Dave Glenn (Presque Isle), Jim Breinling (West Region) and Dr. Doo-Hong Min.……………………………..………………….… 53 W.W. Kirk, R.L. Schafer and D. Berry……………………...….………... 75 Chad D. Lee and Chris M. Long…………………………………….…… 81 W.W. Kirk and R.L. Schafer and D. Berry……………………..………... 71 W.W. Kirk and R.L. Schafer and D. Berry……………………..………... 69 SEED TREATMENT, IN-FURROW AND SEED PLUS FOLIAR TREATMENTS FOR CONTROL OF POTATO STEM CANKER AND BLACK SCURF, 2002 TIMING OF APPLICATION OF SEED TREATMENTS, FOR CONTROL OF FUSARIUM DRY ROT IN POTATOES, 2002 EVALUATION OF FUNGICIDES AS SOIL APPLICATIONS AT PLANTING AND FOLIAR APPLICATIONS FOR PINK ROT AND PYTHIUM LEAK CONTROL, 2002 CONTROL OF VOLUNTEER POTATO (Solanum tuberosum) IN A CORN (Zea mays) ROTATION WITH POSTEMERGENCE HERBICIDE TREATMENTS INTEGRATED CONTROL OF COMMON SCAB (Streptomyces scabies) IN POTATO. I. CULTIVAR RESISTANCE AND SOIL MOISTURE TREATMENTS IN GREENHOUSE AND FIELD EXPERIMENT. II. INDUCING RESISTANCE IN POTATO TO COMMON SCAB IN FIELD EXPERIMENT. III. QUANTIFICATION OF PATHOGENIC S. scabies IN GREENHOUSE EXPERIMENT 2002 REPORT TO MPIC E.C. Poole, D.S. Douches, R. Hammerschmidt, and W.W. Kirk……….. 84 PAGE George W. Bird…………………………………………………………. 91 2002 NEMATODE RESEARCH ANNUAL REPORT MICHIGAN POTATO INDUSTRY COMMISSION POTATO INSECT BIOLOGY AND MANAGEMENT Beth Bishop, Ed Grafius, Adam Byrne, Walt Pett, and Eric Bramble……………...………………………………………... 113 NITROGEN AND SPACING AS FACTORS IN PRODUCTION OF ADVANCED BREEDING LINES (TABLESTOCK AND CHIP PROCESSING) FROM MICHIGAN STATE UNIVERSITY Chris M. Long, Dr Sieg S. Snapp, Dr. D.S. Douches, and Dr. R.W. Chase……………………………...……………………... 131 Sieg Snapp, Judith Nyiraneza, and Kitty O’Neil…………………..…... 139 Sieg Snapp, Chris Long and Deirdre Holcroft……...…………………... 144 IMPROVING PRODUCTIVITY AND SOIL QUALITY IN SHORT POTATO ROTATIONS 2002 RESEARCH REPORT CALCIUM NUTRITION FOR IMPROVED QUALITY AND STORAGE OF POTATOES 2002 RESEARCH REPORT TOLERANCE OF MYCELIUM OF DIFFERENT GENOTYPES OF Phytophthora Infestans (Mont.) DE BARY TO EXPOSURE TO TEMPERATURE BELOW 0ºC FOR EXTENDED DURATIONS. HOST PLANT RESISTANCE AND REDUCED RATES AND FREQUENCIES OF FUNGICIDE APPLICATION TO CONTROL POTATO LATE BLIGHT (CO-OPERATIVE TRIAL QUAD STATE GROUP 2002) William W. Kirk…………………………………………….….………. 149 W.W. Kirk, J.B. Muhinyunza, D.S. Douches, C. Thill, J. Jang and S. Thompson………………………………………..……..... 159 W.W. Kirk, R.L. Schafer and D. Berry……...………………….………. 166 EVALUATION OF HEADLINE PROGRAMS FOR POTATO LATE BLIGHT CONTROL, 2002. EVALUATION OF REASON, SCALA, GAVEL, AND EBDC-BASED PROGRAMS FOR POTATO LATE BLIGHT CONTROL, 2002. W.W. Kirk, R.L. Schafer and D. Berry……...………………….………. 167 PAGE W.W. Kirk, R.L. Schafer and D. Berry……...………………….………. 169 W.W. Kirk, R.L. Schafer and D. Berry...……………………….………. 171 EVALUATION OF SONATA-BASED PRODUCTS AND FUNGICIDE PROGRAMS FOR FOLIAR DISEASE CONTROL, 2002. EVALUATION OF HEADLINE, RANMAN, EBDC AND CHLOROTHALONIL-BASED PROGRAMS FOR POTATO LATE BLIGHT CONTROL, 2002 EVALUATION OF TANOS, FAMOXATE AND CURZATE PROGRAMS FOR POTATO LATE BLIGHT AND Alternaria spp. CONTROL, 2002 SUMMARY REPORT FOR THE 2001-2002 DR. B.F. (BURT) CARGILL POTATO DEMONSTRATION STORAGE B. Sackett, C. Long, D. Crawford, T. Forbush, S. Crooks, G. Perkins T. Young, J. Walther, D. Smucker (Montcalm CED), Troy Sackett, Randy Styma and Paul Main………………………….………………… 175 W.W. Kirk, R.L. Schafer and D. Berry...……………………….………. 173 2002 MICHIGAN POTATO RESEARCH REPORT C. M. Long, Coordinator INTRODUCTION AND ACKNOWLEDGMENTS The 2002 Potato Research Report contains reports of the many potato research projects conducted by MSU potato researchers at several locations. The 2002 report is the 34rd report, which has been prepared annually since 1969. This volume includes research projects funded by the Special Federal Grant, the Michigan Potato Industry Commission (MPIC), GREEEN and numerous other sources. The principal source of funding for each project has been noted at the beginning of each report. We wish to acknowledge the excellent cooperation of the Michigan potato industry and the MPIC for their continued support of the MSU potato research program. We also want to acknowledge the significant impact that the funds from the Special Federal Grant have had on the scope and magnitude in several research areas. Many other contributions to MSU potato research have been made in the form of fertilizers, pesticides, seed, supplies and monetary grants. We also recognize the tremendous cooperation of individual producers who participate in the numerous on-farm projects. It is this dedicated support and cooperation that makes for a productive research program for the betterment of the Michigan potato industry. We further acknowledge the professionalism of the MPIC Research Committee. The Michigan potato industry should be proud of the dedication of this Committee and the keen interest they take in determining the needs and direction of Michigan's potato research. Special thanks goes to Dick Crawford for the management of the MSU Montcalm Research Farm and the many details, which are a part of its operation. Thanks also to Don Smucker, Montcalm CED for maintaining the weather records from the MRF computerized weather station. Also, we want to recognize Barb Smith at MPIC for helping with the details of this final draft. WEATHER The overall 6-month average temperatures during the 2002 growing season were comparable to the 2001 season, but slightly higher than the 15-year average (Table 1). There were 11 days that the temperature reached 90°F or above and 15 days in April that the temperature was below 32°F. The average maximum temperatures for July, August, and September of 2002 were 4-6 degrees higher than the 15-year average. Rainfall for April through September was 22.65 inches which is slightly higher than the 15 year average (Table 2). Rainfall recorded during the month of August was the second highest in 15 years. Irrigation at MRF was applied 9 times from June 18th to August 10th averaging 0.61 inches for each application. The total amount of irrigation water applied during this time period was 5.5 inches. The 15-year summary of average maximum and minimum temperatures (°F) during Table 1. the growing season at the Montcalm Research Farm. April May June July August September 6-Month Average 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 15 Year Average Table 2. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. 50 52 46 56 NA NA 60 52 46 51 50 54 57 50 51 51 50 50 48 54 60 52 51 59 50 56 61 53 51 56 31 32 NA 40 34 33 34 31 31 31 37 37 34 37 36 46 34 43 47 42 45 43 45 44 39 51 48 49 49 42 49 44 47 47 46 46 51 45 51 50 52 48 49 48 52 75 74 NA 74 70 70 71 72 69 69 75 73 71 72 73 60 59 58 60 54 61 60 60 55 57 58 62 56 58 62 84 79 78 80 75 79 75 82 80 73 81 76 79 72 81 53 53 55 59 50 55 55 57 57 56 56 55 57 57 58 88 83 79 81 76 81 79 82 76 80 82 84 77 83 85 61 55 57 57 51 60 55 65 59 55 60 56 57 70 58 71 71 72 69 69 64 73 70 70 69 76 73 70 69 77 74 72 64 71 70 68 66 66 64 59 75 71 70 70 63 82 81 77 82 76 74 78 81 75 79 77 77 75 78 79 34 68 44 78 56 81 59 78 58 71 48 72 50 55 The 15-year summary of precipitation (inches per month) recorded during the growing season at the Montcalm Research Farm. Year 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 15 Year Average April 1.82 2.43 1.87 4.76 3.07 3.47 3.84 3.65 2.46 2.02 2.40 5.49 3.18 3.28 2.88 3.11 May 0.52 2.68 4.65 3.68 0.47 3.27 2.63 1.87 3.99 3.13 2.21 5.07 6.46 6.74 4.16 3.44 June 0.56 4.85 3.53 4.03 1.18 4.32 6.04 2.30 6.28 3.54 1.82 5.82 4.50 2.90 3.28 3.66 July 2.44 0.82 3.76 5.73 3.51 2.58 5.16 5.25 3.39 2.80 0.40 4.29 3.79 2.49 3.62 3.34 August September 3.44 5.52 4.06 1.75 3.20 6.40 8.05 4.59 3.69 2.71 2.22 5.46 5.28 5.71 7.12 5.36 1.33 3.64 1.50 3.90 3.56 1.18 1.38 2.96 1.46 3.05 4.03 5.25 4.43 1.59 Total 14.14 17.63 21.51 21.45 15.33 23.60 26.90 19.04 22.77 15.66 12.10 30.16 28.46 25.55 22.65 4.61 2.97 21.13 GROWING DEGREE DAYS Table 3 summarizes the cumulative, base 50°F growing degree days (GDD) for May through September, 2002. The total GDD for 2002 were 2,613, 234 GDD higher than 2001, and significantly higher then the 10-year average. Table 3. Growing Degree Days* - Base 50°F. 2299 270 781 1398 1967 *1993-2002 data from the weather station at MSU Montcalm Research Farm (Don Smucker, Montcalm County Extension Director). Cumulative Monthly Totals May June July August September 261 231 202 201 110 427 317 313 317 319 698 730 779 681 635 932 865 780 808 903 1348 1318 1421 1177 1211 1545 1573 1301 1441 1646 1950 1780 2136 1776 1637 2180 2070 1851 2079 2214 2153 2148 2348 2116 1956 2616 2401 2256 2379 2613 Year 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 10 Year Average PREVIOUS CROPS, SOIL TESTS AND FERTILIZERS The general potato research area was planted to rye in the fall of 2000 and was harvested late in the summer of 2001. The area was fumigated in the fall. The land was disked and the field fitted for potato planting in the spring 2002. Potato early die was not a problem in 2002. The soil test analysis for the general crop area was as follows: lbs/A pH 6.2 P2O5 431 K2O 178 Ca 571 Mg 189 The fertilizers used in the general plot area are as follows. Variances in fertilizers used for specific research projects are included in the individual project reports. Application Broadcast at plow down At planting At emergence 1st Early side dress 2nd Late side dress (late varieties) Analysis Rate Nutrients (N-P205-K20) 0-0-60 19-17-0 46-0-0 46-0-0 46-0-0 300 lbs/A 18 gpa 135 lbs/A 197 lbs/A 197 lbs/A 0-0-180 38-34-0 62-0-0 91-0-0 91-0-0 HERBICIDES AND PEST CONTROL Hilling was done in late May, followed by a pre-emergence application of Sencor DF 0.66 lb/A and Dual at 2.0 pints/A. Admire was applied at planting at a rate of 13.6 oz/A. Cygon was applied once in late July at 1 pint/A. Fungicides used were Bravo, Previcur, Polyram 80DF and Terrinil over 12 applications. Potato vines were desiccated with Reglone once in mid September at a rate of 1 pint/A. E. Estelle Department of Crop and Soil Sciences Michigan State University East Lansing, MI 48824 2002 POTATO BREEDING AND GENETICS RESEARCH REPORT David S. Douches, J. Coombs, K. Zarka, Susannah Cooper, L. Frank, J. Driscoll, and Cooperators: R.W. Chase, Ray Hammerschmidt, Ed Grafius Willie Kirk, George Bird, and Chris Long At MSU, we conduct a multi-disciplinary program for potato breeding and variety INTRODUCTION development that integrates traditional and biotechnological approaches. We conduct variety trials of advanced selections and field experiments at MSU research locations (Montcalm Research Farm, Lake City Experiment Station, Muck Soils Research Farm and MSU Soils Farm), we ship seed to other states and Canadian provinces for variety trials, and we cooperate with Chris Long on 16 grower trials throughout Michigan. Through conventional crosses in the greenhouse, we develop new genetic combinations in the breeding program, and also screen and identify exotic germplasm that will enhance the varietal breeding efforts. With each cycle of crossing and selection we are seeing directed improvement towards improved varieties (e.g. combining chip-processing, scab resistance and late blight resistance). In addition, our program has been utilizing genetic engineering as a tool to introduce new genes to improve varieties and advanced germplasm for traits such as solids, insect resistance and disease resistance. We feel that these in-house capacities (both conventional and biotechnological) put us in a unique position to respond to and focus on the most promising directions for variety development and effectively integrate the breeding of improved chip-processing and tablestock potatoes. potato industry. Traits of importance include yield potential, disease resistance (scab, late blight and early die), insect (Colorado potato beetle) resistance, chipping (out-of-the-field, storage, and extended cold storage) and cooking quality, bruise resistance, storability, along with shape, internal quality and appearance. We are also developing potato tuber moth resistant lines as a component of our international research project. If these goals can be met, we will be able to reduce the grower’s reliance on chemical inputs such as insecticides, fungicides and sprout inhibitors, and improve overall agronomic performance with new potato varieties. PROCEDURE I. Varietal Development the most promising cultivars and advanced breeding lines. The parents are chosen on the The breeding goals at MSU are based upon current and future needs of the Michigan Each year, during the winter months, 500-1000 crosses are made using about 150 of With the Demonstration Storage facility adjacent to the Montcalm Research Farm basis of yield potential, tuber shape and appearance, chip quality, specific gravity, disease resistance, adaptation, lack of internal and external defects, etc. These seeds are then used as the breeding base for the program. We also obtain seedling tubers or crosses from other breeding programs in the US. The seedlings are grown annually for visual evaluation (size, shape, set, internal defects) at the Montcalm and Lake City Research Farms as part of the first year selection process of this germplasm each fall. Each selection is then evaluated post harvest for specific gravity and chip processing. These selections each represent a potential variety. This system of generating new seedlings is the initial step in an 8-12 year process to develop new varieties. This step is followed by evaluation and selection at the 8- hill and 20-hill stages. The best selections out of the four-year process are then advanced for testing in replicated trials (Preliminary, Adaptation, Dates-of-Harvest, Grower-cooperator trials, North Central Regional Trials, Snack Food Association Trials, and other out-of-state trials) over time and locations. The agronomic evaluation of the advanced breeding lines in the replicated trials is reported in the annual Potato Variety Evaluation Report. II. Evaluation of Advanced Selections for Extended Storage we are positioned to evaluate advanced selections from the breeding program for chip- processing over the whole extended storage season (October-June). Tuber samples of our elite chip-processing selections are placed in the demonstration storage facility in October and are sampled monthly to determine their ability to chip-process from colder (42-46°F) and/or 50˚F storage. III. Germplasm Enhancement "diploid" (2x chromosomes) breeding program in an effort to simplify the genetic system in potato (which normally has 4x chromosomes) and exploit more efficient selection of desirable traits. This added approach to breeding represents a large source of valuable germplasm, which can broaden the genetic base of the cultivated potato. The diploid breeding program germplasm base at MSU is a synthesis of seven species: S. tuberosum (adaptation, tuber appearance), S. raphanifolium (cold chipping), S. phureja (cold-chipping, specific gravity, PVY resistance, self-compatability), S. tarijense and S. berthaultii (tuber appearance, insect resistance, verticillium wilt resistance), S. microdontum (late blight resistance) and S. chacoense (specific gravity, low sugars, dormancy and leptine-based insect resistance). In general, diploid breeding utilizes haploids (half the chromosomes) from potato varieties, and diploid wild and cultivated tuber-bearing relatives of the potato. Even though these potatoes have only half the chromosomes of the varieties in the U.S., we can cross these potatoes to transfer the desirable genes by conventional crossing methods via 2n pollen. IV. Through transgenic approaches we have the opportunity to introduce new genes into our cultivated germplasm that otherwise would not be exploited. It has been used in potato as a tool to improve commercially acceptable cultivars for specific traits. Our laboratory has 10 years experience in Agrobacterium-mediated transformation to introduce genes into important potato cultivars and advanced breeding lines. We presently have genes in vector To supplement the genetic base of the varietal breeding program, we have a Integration of Genetic Engineering with Potato Breeding constructs that confer resistance to PVY, Colorado potato beetle, potato tuber moth, broad- spectrum disease resistance via the glucose oxidase (GO) gene, late blight resistance with the resveratrol synthase (RS) and divinyl ether synthase (DES) genes, and cold/frost resistance (COR15). We also have the glgC16 gene (ADP-glucose pyrophosphorylase (AGPase) or starch gene) from Monsanto to modify starch and sugar levels in potato tubers. Furthermore, we are investing our efforts in developing new vector constructs that use alternative selectable markers and give us the freedom to operate from an intellectual property rights perspective. In addition, we are exploring transformation techniques that eliminate the selectable marker (antibiotic resistance) from the transgenic plants. V. Variety Release varieties and is in the process of licensing these new varieties to the Michigan Potato Industry Commission. Each year the best lines will be considered for release. In 2003 MSF373-8, with the name Boulder being considered, will be brought forward. RESULTS AND DISCUSSION I. Varietal Development Breeding Beginning in 2002, the MSU breeding program has named and released its first three The MSU potato breeding and genetics program is actively producing new germplasm and advanced seedlings that are improved for cold chipping, and resistance to scab, late blight, and Colorado potato beetle. For the 2002 field season, progeny from over 600 crosses were planted and evaluated. Of those, the majority were crosses to select for round whites (chip-processing and tablestock), with the remainder to select for yellow flesh, long/russet types, red-skin, and novelty market classes. In addition to crosses from the MSU breeding program, crosses were planted and evaluated from collaborative germplasm exchange from other breeding programs including North Dakota State University, University of Minnesota, and the USDA/ARS program at the University of Wisconsin. During the 2002 harvest, about 1200 selections were made from the 35,000 seedlings grown at the Montcalm Research Farm. Following harvest, specific gravity was measured and potential chip-processing selections were chipped out of the field. All potential chip- processing selections will be tested in January or March 2003 directly out of 42°F and 50°F storage. Atlantic (50°F chipper) and Snowden (45°F chipper) are chipped as check cultivars. Selections have been identified at each stage of the selection process that have desirable agronomic characteristics and chip-processing potential. At the 8-hill and 20-hill evaluation state, 450 and 140 selections were made, respectively. Table 1 lists some of the potential lines for grower trials in year 2003. Chip-Processing program, despite switching to a more stringent screening temperature (42 vs. 45°F storage) a few years ago. Over 70% of the single hill selections have a chip-processing parent in their pedigree. Of those selections, about 75% have a SFA chip score of 1.5 or less. Based upon the pedigrees of the parents we have identified for breeding cold- Excellent chip-processing selections have been identified in the breeding chipping potato varieties, we have a diverse genetic base. We believe that we have at least eight cultivated sources of cold-chipping. We have made various hybrid combinations with these parents from which to pyramid cold-chipping traits and the hybrid populations have been grown out, selected and evaluated. We now have advanced into the crossing block these new MSU selections that have chip quality directly from 42°F storage. Examination of pedigrees shows up to three different cold-chipping germplasm sources have been combined in these selections. Promising chip-processing lines are MSF099-3 (42°F chipper), MSG227-2 (scab resistant 45°F chipper), MSH095- 4, MSH094-8, MSH067-3, MSJ147-1, MSJ126-9Y, MSJ167-1, and late blight resistant chipper MSJ461-1. Tablestock One of our objectives is also to develop improved cultivars for the tablestock industry. Efforts have been made to identify lines with good appearance, low internal defects, good cooking quality, high marketable yield and resistance to scab and late blight. From our efforts we have identified mostly round white lines, but we also have a number of yellow-fleshed and red-skinned lines, as well as long, russet type and purple skin selections that carry many of the characteristics mentioned above. We are also selecting for a dual- purpose russet, round white, red-skin, and improved Yukon Gold-type yellow-fleshed potatoes. Some of the tablestock lines were tested in on-farm trials in 2002, while others were tested under replicated conditions at the Montcalm Research Farm. Promising tablestock lines include MSE221-1 as a scab resistant tablestock, while MSE018-1 is a high yielding tablestock with a large oval shape. MSE192-8RUS and MSE202-3RUS are two russet table selections that have excellent type and scab resistance. MSE149-5Y, MSI005- 20Y and MSJ033-6Y are yellow-fleshed lines with smooth round appearance and high yield potential. MSF373-8 is a high yielding line with large tubers that also chip out of the field. This line is being considered for release as Boulder. Our current tablestock development goals now are to continue to improve the frequency of scab resistant lines, incorporate resistance to late blight along with marketable maturity and excellent tuber quality, and select more russet lines. Disease and Insect Resistance Breeding 2002 MSU scab nursery indicate that 16 of 160 lines evaluated demonstrated strong resistance (no evidence of infection) to common scab in 2002. In addition, 10 other MSU breeding lines showed moderate scab resistance. The limitation of breeding for scab resistance is the reliance on the scab nursery. The environmental conditions can influence the infection each year, thus multiple year data provides more reliable data. A laboratory- based screening process is currently under development that would use thaxtomin in tissue culture to expedite selection of material with potential scab resistance. Since the mid-1990’s we have directed efforts to identify sources of late blight resistance and use this resistance to breed late blight resistant varieties. At MSU, we have also participated in the national late blight trial and we have conducted our own efforts to use field and greenhouse screening to identify additional sources of resistance that can be used by the breeding community. In the past six years the MSU breeding Disease screening for scab has been an on-going process this 1988. Results from the program has intensely evaluated over 700 crosses between late blight resistant x late blight susceptible parents and have identified parents that transmit strong late blight resistance to the highest percentage of the offspring. As of 2002, based upon six years of inoculated field experiments, we have at least eight sources of foliar resistance to the US8 genotype of Phytophthora infestans (Mont.) that have different pedigrees from which their resistance is derived. The resistance in Jacqueline Lee has now held resistance for six years of testing. MSJ461-1, the chip-processing selection, has the same late blight resistance source as Jacqueline Lee. Our other promising late blight resistant lines that have been tested in replicated agronomic trials are MSJ317-1, MSI152-A, MSJ453-4Y, MSJ456-4 and MSL757-1 (see Potato Variety Evaluation Report for agronomic data). In each of these lines, the resistance is based on a single resistance source. If we rely on a single source of resistance, the varieties developed from this strategy may be overcome by P. infestans at some future date that we cannot predict. Therefore, the most effective breeding strategy is to combine resistance from different pedigrees to build a more durable resistance. Our efforts are now focusing on pyramiding the different resistance sources. Single-hill selections in 2002 also had an exciting number of individuals with pedigrees for potential late blight, Colorado potato beetle or scab resistance or some combination of the three. Of the single hill selections, 40% of progeny have at least one late blight parent, 15% have a Colorado potato beetle resistant parent, and 15% have a scab resistant parent in its pedigree. II. Evaluation of Advanced Selections for Extended Storage: MSU Potato Breeding Chip-processing Results From the MPIC Demonstration Commercial Storage (October 2001 - June 2002) The MSU Potato Breeding Program has been conducting chip-processing evaluations each year on potato lines from the MSU breeding program and from other states. For three years we have been conducting a storage study to evaluate advanced breeding lines with chip-processing potential in the Dr. B. F. (Burt) Cargill Potato Demonstration Storage facility directly adjacent to the MSU Montcalm Research Farm. In October 2001, tuber samples from seven lines in the Montcalm Research Farm trials were placed in the bin to be cooled to 46°F. Tubers from another seven lines were placed in the bin that was to be cooled then held at 52°F. The first samples were chip-processed at MSU in October and then, each month until June 2002. Samples were evaluated for chip-processing color and quality. Table 2 summarizes the chip-processing color of select lines over the 8-month storage season. In the 46°F bin, Snowden was the check variety. In May the Snowden chips went off-color. In contrast only MSG227-2, MSH094-8 and MSH095-4 maintained acceptable chip color until the June 2002 sampling. Of these lines, MSG227- 2 and MSH094-8 maintained the lightest chip color throughout the storage season. Chip- processing ability of MSG227-2 and NY112 was also observed during the past two year’s storage studies in the Demonstration Storage Facility. MSG227-2 also has scab resistance. If the agronomic performance of MSG227-2 is considered acceptable, it will be considered for commercial release after the 2003 season. In the 52°F bin Atlantic and Pike were used as check varieties and both varieties chip-processed acceptably until April. Of the six advanced breeding lines evaluated, Liberator and MSJ461-1 chip-processed acceptably throughout the storage season. Liberator offers chip-processing from storage and scab resistance. MSJ461-1 had the most consistent and lightest chip color throughout the storage season. MSJ461-1 also offers strong foliar late blight resistance along with the chip-processing quality; however the solids content is lower than other chip-processing lines. In addition, MSF099-3 was grown by Sandyland Farms in 2001 and placed in one In 2002, about 5% of the populations evaluated as single hills were diploid. From of the 500 cwt bins. Despite field frost occurring in the harvested tubers, the potatoes chip-processed successfully out of the bin in April 2002 at Utz in Pennsylvania. III. Germplasm Enhancement this breeding cycle, we plan to screen the selections chip-processing from storage. In addition, selections were made from over 3,000 progeny that was obtained from the USDA/ARS at the University of Wisconsin. These families represent material from South American potato species and other countries around the world that are potential sources of resistance to Colorado potato beetle, late blight, potato early die, and ability to cold-chip process. About 100 selections were made among the diploid material in 2002. Through GREEEN funding, we were able to initiate a breeding effort to introgress leptine-based insect resistance. From previous research we determined that the leptine-based resistance is effective against Colorado potato beetle. We will be conducting extensive field screening for resistance to Colorado potato beetle in 2003. Late Blight Breeding and Genetics: Mapping Late Blight Resistance in three Populations blight resistance and use these sources for breeding varieties with late blight resistance. In 1999 we initiated a set of studies (via GREEEN) to identify the genes in potato associated with late blight resistance. If we can identify the genes that contribute to late blight resistance we feel that we could more effectively breed varieties with durable late blight resistance. A diploid potato population was developed with the objectives to map quantitative trait loci (QTL) conferring resistance to Phytophthora infestans (Mont.) de Bary and other agronomic traits using simple sequence repeats (SSR) and isozymes and to examine associations between late blight resistance and other agronomic traits. The mapping population was a cross between a late blight resistant selection of Solanum microdontum Bitter and a susceptible diploid advanced breeding clone. A second diploid population derives its late blight resistance from S. berthaultii. The third population is tetraploid and the resistance comes from Jacqueline Lee. Based upon field trials at the Muck Soils Research Farm, Bath, MI between 1999 and 2002, we have identified major late blight resistance genes in the three populations. Currently, one chromosome region containing the resistance is linked to a genetic marker has been identified in S. microdontum. Following the gene mapping analyses this winter, we will find the other two major resistances linking with a genetic The major QTL associated with late blight A high priority objective of the breeding program is to identify sources of late resistance is suitable for marker-assisted selection to introgress a new source of resistance to P. infestans to the cultivated tetraploid germplasm of potato. The tetraploid cross for mapping (Jacqueline Lee x MSG227-2) offers more than just mapping late blight resistance genes. This cross has traits such as late blight resistance, scab resistance, chip-processing, specific gravity, maturity all segregating at one time. The original cross had over 300 progeny. From those, about 75% had acceptable tuberization characteristics. Following late blight screening at the Muck Soils Research Farm, 41 progeny had foliar late blight resistance. Of those late blight resistant progeny, about 75% had acceptable yield and tuber type for selection. About 30 lines were chip-processed. Of those selections about 10 had acceptable chip-processing color, with 5 having acceptable solids levels in the tubers. About 25 of the selected progeny are being advanced for further evaluation in 2003. IV. Integration of Genetic Engineering with Potato Breeding The program has been conducting transformations of potato to introduce a variety of transgenes. Currently we have genetically engineered plants that express the Bt-cry3A gene to control the Colorado potato beetle, the glucose oxidase and resveratrol synthase genes for disease resistance, and the AGPase gene for low sugars and high solids. Assessment of Natural (Glandular Trichomes and Glycoalkaloid-Based) and Engineered (Bt-cry3A) Potato Host Plant Resistance Mechanisms for Control of Colorado potato beetle: Caged no-choice studies. The Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), is the leading insect pest of potato (Solanum tuberosum L.) in northern latitudes. Host plant resistance is an important tool in an integrated pest management program for controlling insect pests. A field study was conducted in 2002 to compare natural (glandular trichomes (NYL235-4) and glycoalkaloid-based (ND5873-15)), engineered (Bt-cry3A: NO8.8), and combined (glandular trichomes + Bt-cry3A (L28.3) and glycoalkaloids + Bt-cry3A (ND8.01) transgenic potato lines) host plant resistance mechanisms of potato for control of Colorado potato beetle. Six different potato lines representing five different host plant resistance mechanisms were evaluated in caged studies (no-choice) at the MSU campus farms. Each cage with 10 plants represented one plot. The cages were arranged in a randomized complete block design consisting of three replications. Observations were recorded weekly for a visual estimation of percent defoliation by Colorado potato beetles, and the number of egg masses, larvae, and adults. The Bt-cry3A transgenic, and the combined resistance lines were effective in controlling feeding by Colorado potato beetle adults and larvae. Effectively no feeding was observed in the glycoalkaloid + Bt-cry3A transgenic line. The high glycoalkaloid line had less feeding, but the beetles clipped the petioles, which led to greater defoliation in the first few weeks. Foliage re-growth occurred by the end of the season. The glandular trichome line suffered less feeding than the susceptible control. Based on these results, the Bt- cry3A gene in combination with glandular trichome or glycoalkaloid-based host plant resistance mechanisms is an effective strategy that could be used to develop potato varieties for use in a resistance management program for control of Colorado potato beetle. Figure 1 shows the results of caged trial in 2002. In 2001 and 2002, we had extensive field testing for agronomic performance in Bt-cry3A-transgenic line Agronomic Trial replicated trials of our most advanced Bt-cry3A transgenic lines. Based upon 2001 agronomic performance and 2002 Bt-cry3A protein concentrations in foliage, 12 of 26 transgenic lines were eliminated. Table 3 summarizes the results from the Advanced Bt- cry3A Breeding Line Preliminary Trial at the Montcalm Research Farm. In general, the Bt- cry3A transgenic lines had similar agronomic and tuber characteristics compared to the non- transgenic parental line. These selections represent a diverse portfolio of Bt-cry3A lines that could be commercialized if the intellectual property rights and regulatory requirements could be met. We will maintain these lines in our program. If the acceptance of transgenic food crops becomes deregulated, we will consider these lines for commercialization. International Project to Develop Potato Tuber Moth Resistant Potatoes (USAID) Potato tuber moth, Phthorimaea operculella (Zeller), is the most serious insect pest of potatoes worldwide. The introduction of the Bacillus thuringiensis (Bt) toxin gene via genetic engineering offers host plant resistance for the management of potato tuber moth. The primary insect pest in Egyptian potato production, like many other countries in the Middle East, is the potato tuber moth. In the field, the moths lay their eggs on the potato foliage and the hatched larvae mine the foliage and the stems. This feeding damage leads to irregular transparent tunnels in the leaves and weakening of the stem. The larvae attack the tubers through infected stems or directly from eggs, which are oviposited on exposed tubers or where soil cracks allow moths to reach the tubers. Larvae mine the tuber in the field and in storage reducing potato quality and increasing the potential for pathogen infection. Field and storage studies were conducted to evaluate Bt- cry5 potato lines for resistance to potato tuber moth in Egypt under natural infestations and their agronomic performance in both Egypt and Michigan. From 1997-2001, field experiments were conducted at the International Potato Center (CIP) Research Station, Kafr El-Zyat, Egypt and/or Agricultural Genetic Engineering Institute (AGERI), Giza, Egypt to evaluate resistance to tuber moth. A total of 27 Bt-transgenic potato lines from six different Bt constructs were evaluated over a five-year period. Following harvest and evaluation of the agronomic trials, storage evaluation of potato tuber moth damage was done at the CIP Research Station. The 1997 field trial was the first field test of genetically engineered crops in Egypt. Field tests to assess potato tuber moth resistance in Egypt were able to differentiate between the Bt-transgenic lines and the non-transgenic lines/cultivars in 1999, 2000 and 2001. The Bt-cry5-Spunta lines (Spunta-G2, Spunta- G3, and Spunta-6a3) were the most resistant lines in field with 99-100% of tubers free of damage. In the 2001 storage study, these lines were also over 90% free of tuber moth damage after 3 mo. NYL235-4.13, which combines glandular trichomes with the Bt- cry5/gus fusion construct also, had a high percentage of clean tubers in the field studies. In agronomic field trials in Michigan from 1997-2001 the Bt-transgenic lines in most instances performed similar to the non-transgenic line in the agronomic trials, however in Egypt (1998-1999) the yields were less than half of those in Michigan. Expression of the Bt-cry5 gene in the potato tuber and foliage will provide the seed producer and grower a tool in which to reduce potato tuber moth damage to the tuber crop in the field and storage. Two transgenic 'Spunta' clones, G2 and G3, produced high control levels of mortality in first instars of potato tuber moth in detached-leaf bioassays (80 - 83% mortality), laboratory tuber tests (100% mortality), and field trials in Egypt (99-100% undamaged tubers). Reduced feeding by Colorado potato beetle first instars was also observed in detached-leaf bioassays (80-90% reduction). Field trials in the U.S. demonstrated that the agronomic performance of the two transgenic lines was comparable to 'Spunta'. We are currently working with USAID, Syngenta and South Africa to commercialize the Spunta-G2 and Spunta-G3 lines. cry5 gene. We hope to have approval to field test these in Mexico in 2003. Transformation and Evaluation of Potato Cultivars with the glgC16 (AGPase) Gene The processing parameters are strictly defined for potato. For chip processing, a We have also transformed Atlantic, Lady Rosetta and Jacqueline Lee with the Bt- specific gravity of 1.080 is the threshold for processing cultivars. In addition, a low reducing sugar level must occur in the potato tuber at harvest and also during storage prior to processing. Potato breeding of improved cultivars for chip processing has had a low probability of success because of the need to combine numerous economic characteristics into one genotype. In some cases, the genotype may be suitable for chip- processing, but the tuber specific gravity falls below the 1.080 threshold. ADP glucose pyrophosphorylase is an enzyme, which uses the glucose 1-phosphate molecule as a substrate for the biosynthesis of starch. An ADP glucose pyrophosphorylase gene (glgC- 16) has been isolated from E. coli and placed in a plant transformation vector under the control of the patatin promoter. One goal of this study is to examine the value of glgC-16 to raise the dry matter content for potato tubers. We have targeted transformation of with the AGPase gene towards lines that have below average solids content. In 2001 and 2002 agronomic field trials were conducted to evaluate agronomic performance, specific gravity, chip-processing, and bruise susceptibility of Onaway, MSE149-5Y and their AGPase transgenic lines. The tuber appearance of the various AGPase lines was similar to non-transgenic Onaway and the MSE149-5Y lines (Table 4A and 4B). The results in 2001 and 2002 were, in general, were similar between years. Most of the MSE149-5Y and Onaway AGPase transgenic lines had similar yields, although slightly lower in some lines compared to the non- transgenic parents. In general, the tuber size distribution was quite comparable, although there was a reduction in the number of oversize (>3.25”) tubers. The specific gravity for the Onaway and MSE149-5Y AGPase lines was higher than the non-transgenic parents in almost all cases. We also observed a higher incidence of internal defects, specifically hollow-heart, in these AGPase lines. Unfortunately, the results from the blackspot bruise susceptibility tests indicate that the transgenic lines that had higher specific gravities were also had higher blackspot bruise potential (e.g. ONAGP3, ONAGP1, ONAGP2, EAGP24, EAGP4, EAGP9, and EAGP3). We are now making crosses with these AGPase lines to see the effect of the AGPase gene expression on progeny. The MSU breeding program has now named and released its first varieties and is in V. Variety Release the process of licensing the new varieties to the Michigan Potato Industry Commission. Three potato varieties were released in 2001: Jacqueline Lee (MSG274-3), Liberator (MSA091-1), and Michigan Purple. MSU is currently licensing these three varieties to MPIC and working out procedures to market these varieties. MSF373-8 is being considered for release in 2003. The named Boulder is being considered because of the large tuber size and low incidence of internal defects. Boulder is a round white selection with medium specific gravity that can be used in both the tablestock and chip-processing markets. The tubers will chip process out-of- the-field and from 10°C storage. The tubers of Boulder are large in size with a low incidence of internal defects. Boulder was tested in Michigan State University trials, the North Central Regional Trials, on-farm trials in Michigan and other out-of-state replicated agronomic trials. Under irrigated conditions in Michigan the yield is similar to Atlantic, but specific gravity is less. Boulder has a full-season vine maturity that is similar to Snowden, but the tubers size early. describe potato varieties. This fingerprint method was based upon isozyme proteins in the potato tubers or leaf tissue. This method has been very reliable, but from a practical point of view, the isozyme protein method requires living tissue to express the proteins. Our goal has been develop a fingerprint system that is DNA-based so that the living tissue requirement would be eliminated. We chose an SSR-based system because of the reproducibility of the PCR-based DNA amplification system. Sixteen potato varieties were chosen for the baseline study. Fifteen SSR primer sets were used. DNA was isolated from fresh leaves, fresh tubers, tuber skins, freeze-dried leaf tissue and freeze-dried tuber tissue. Of the 15 SSR sets, 10 sets amplified readable bands on Metaphor agarose gels that could be used to separate potato varieties. In most cases the varieties could be discriminated with as few as 3 SSR primer sets. Moreover, DNA was able to be isolated from all five tissue sources and obtain repeatable band patterns. This ability to isolate DNA from freeze-dried tissue will allow us to fingerprint varieties when fresh tissue is not available for testing. This SSR fingerprint system can be used alone or in combination with the original isozyme fingerprint system. The seedling generation was grown in 1994, followed by two years of selection and seed multiplication at the Lake City Experiment Station, Lake City, MI. Seed increase was located to the Lake City Experiment Station. Since 1998, Boulder has been tested in replicated agronomic trials at the Montcalm Research Farm, Entrican, MI and in the scab nursery at the Michigan State University Soils Farm, East Lansing, MI. In 2000 it was entered into grower on-farm trials in Michigan and the North Central Regional Trial. In 2001 was placed into commercial seed production. VI. Development of a DNA-based Fingerprint System for Potato Varieties Since 1990 our potato program has offered a fingerprint service to identify and Table 1. Potential Lines for 2003 On-Farm Grower Trials Line Female Pedigree Male Comments Tollocan Tablestock JACQUELINE LEE MICHIGAN PURPLE W870 MSE018-1 MSE192-8RUS MSE202-3RUS MSE221-1 MSF373-8 MSG050-2 MSH031-5 MSI005-20Y MSI152-A MSJ033-10Y MSJ317-1 Chaleur Maris Piper W877 Russet Norkotah Gemchip A8163-8 Frontier Russet A8469-5 Superior MS702-80 Eramosa MSB110-3 MSA097-1Y Mainestay MSA097-1 B0718-3 MS700-83 NY88 NYL235-4 MSC108-2 Penta B0718-3 Penta Prestile Late blight resistant, oval yellow Bright purple skin, white flesh Also storage chipper Scab resistant russet (Norkotah replacement) Scab resistant russet Scab resistant (Superior replacement) Chips out of the field, large tubers Flat, round, bright skin Bright skin Yukon appearance Late blight resistant, round white Yellow, Scab resistant Late blight resistant, round white Processing MSE018-1 MSF099-3 MSF373-8 MSG227-2 MSH067-3 MSH094-8 MSH095-4 MSH112-6 MSH228-6 MSH360-1 MSI002-3 MSJ080-1 MSJ167-1 MSJ453-4Y MSJ456-4 MSJ461-1 Gemchip Snowden MS702-80 Prestile MSC127-3 MSE251-1 MSE266-2 Michigold MSC127-3 E55-35 MSA091-1 MSC148-A P84-13-12 Tollocan Tollocan Tollocan W877 Chaleur NY88 MSC127-3 W877 W877 OP Zarevo OP MSF077-8 MSF134-1 S440 MSE250-2 MSA091-1 Conestoga NY88 Storage chipper, late 42 °F chipper Chips out of the field, large tubers Scab resistant Flat, round 45 °F chipper 45 °F chipper 42 °F chipper, high solids Scab tolerant Scab tolerant High yield and solids High yield High yield and solids Late blight resistant, yellow Late blight resistant Late blight resistant Table 2. 2001-2002 DEMONSTRATION STORAGE CHIP RESULTS Chip Scores represented using SFA Scale† POTATO LINE BIN#4 [46 °F] MSG227-2 MSH094-8 MSH095-4 MSH098-2 DAKOTA PEARL SNOWDEN W1386 BIN#5 [52 °F] LIBERATOR ATLANTIC MSG015-C MSH067-3 MSJ461-1 NY120 PIKE LSD0.05 2001 DOH* CWT/A 2001 2001 DOH* SCAB†† US#1 TOTAL SP GR RATING Sample Dates: 11/7/2001 12/5/2001 1/1/2002 2/13/2002 3/13/2002 4/10/2002 5/8/2002 6/3/2002 57 °F 56 °F 47 °F 48 °F 47 °F 50 °F 56 °F 62 °F Bin Temperature (oF) 403 370 444 344 320 396 345 395 448 304 370 300 451 355 63 449 420 496 381 407 458 436 460 491 384 420 451 488 388 1.073 1.073 1.080 1.074 1.069 1.076 1.073 1.075 1.081 1.067 1.078 1.067 1.074 1.080 57 0.003 0.3 1.3 0.7 1.0 0.7 - 1.5 0.3 1.8 1.0 2.0 1.0 0.3 - 1.5 1.0 1.0 1.5 1.5 1.0 1.5 1.0 1.0 1.0 1.0 1.0 1.0 1.5 1.5 2.0 1.5 1.5 1.5 1.0 1.5 1.0 1.5 1.5 1.5 2.5 1.0 2.5 1.0 1.0 1.5 1.5 1.5 1.0 2.0 1.5 1.5 1.5 1.5 2.0 1.5 2.0 2.0 1.5 2.0 2.5 2.5 2.5 1.5 1.5 2.0 2.5 2.0 2.5 2.5 2.5 57 °F 56 °F 52 °F 52 °F 54 °F 54 °F 55 °F 62 °F 1.5 1.5 2.0 1.0 1.5 1.0 1.0 1.0 1.5 2.0 1.0 1.0 1.0 1.0 2.0 1.5 2.0 1.5 1.5 1.0 1.5 2.0 2.5 2.0 1.5 1.5 1.0 1.5 1.5 1.5 2.0 1.5 1.5 1.0 1.0 1.0 1.5 3.0 1.5 1.0 2.0 1.5 1.5 2.0 3.5 3.5 1.5 2.0 1.5 1.5 2.5 4.5 3.5 1.5 2.5 2.0 †CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. ††SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. *Agronomic data from Date of Harvest, Round-White Late Harvest (DOH) Trial; Montcalm Research Farm, September 21, 2001. Chip scores were from two-slice samples from five tubers of each line collected at each sample date. Table 3. MSU ADVANCED Bt-cry3A SELECTIONS PRELIMINARY TRIAL Montcalm Research Farm, 2001-2002. 2001 CWT/A % 2002 CWT/A % LINE MSE018-1 E08.10 MSG274-3 G38.03 ND5873-15 ND8.01 ND8.04 Norwis NO8.03 NO8.08 NO8.28 NY123 NY8.10 NYL235-4 L28.2 L28.3 L28.5 Spunta SP8.3 Yukon Gold YG8.8 YG8.12 ATLNewLeaf RBNewLeaf US#1 524 491 287 231 274 306 303 379 381 328 372 424 328 436 294 316 308 292 332 315 251 265 468 51 TOTAL US#1 SP GR 1.080 1.081 1.075 1.073 1.077 1.079 1.080 1.059 1.060 1.063 1.062 1.080 1.074 ND* ND ND ND ND ND ND ND ND 1.084 1.075 634 547 591 530 311 335 347 402 428 354 415 508 424 533 385 432 455 334 423 350 305 307 501 258 83 90 49 44 88 91 87 94 89 93 90 83 77 82 77 73 68 87 79 90 82 86 93 20 US#1 377 374 336 343 167 141 178 154 177 184 186 370 313 312 288 301 292 313 276 255 175 151 321 112 TOTAL US#1 SP GR 1.074 1.078 1.071 1.073 1.070 1.067 1.070 1.054 1.055 1.055 1.056 1.074 1.069 1.067 1.067 1.069 1.069 1.055 1.056 1.064 1.059 1.062 1.078 1.059 398 400 432 458 227 178 220 165 193 191 194 400 334 397 328 345 348 358 315 282 186 167 349 155 95 93 78 75 74 79 81 93 92 96 96 93 93 79 88 87 84 87 88 90 94 90 92 72 Lines are grouped by transgenic parental clone family. Parental clone is bolded. *ND: No Data. Table 4A. 2001 and 2002 AGPase AGRONOMIC TRIAL, Moncalm Research Farm. 2001 2002 CHIP US#1 TOTAL US#1 US#1 TOTAL US#1 SP GR SP GR HH1 HH SCORE2 2001 2002 CWT/A 2001 2002 % 2002 CWT/A % 85 84 84 84 90 86 87 89 80 90 85 423 349 311 301 346 33 457 431 419 376 360 331 295 381 59 496 414 373 360 411 51 509 502 481 425 452 369 347 441 53 ONAWAY 366 269 183 319 272 56 324 226 148 283 233 57 MSE149-5Y 314 281 291 236 308 191 168 337 328 335 263 355 215 199 256 46 290 45 0 3 1 2 0 1 0 13 0 29 4 0 7 4 3 4 3 8 22 5 34 16 3.5 3.0 3.5 4.0 2.5 4.0 1.5 2.0 2.0 1.5 1.5 89 84 81 89 93 86 87 90 87 89 84 1.059 1.069 1.071 1.068 1.067 0.002 1.063 1.062 1.063 1.069 1.064 1.070 1.070 1.066 0.003 1.057 1.067 1.065 1.067 1.063 0.003 1.059 1.062 1.062 1.068 1.062 1.069 1.069 1.064 0.003 LINE ONAWAY ONAGP2 ONAGP3 ONAGP1 MEAN LSD0.05 MSE149-5Y EAGP20 EAGP15 EAGP4 EAGP8 EAGP9 EAGP24 MEAN LSD0.05 Potato lines sorted in decreasing 2001 yield within each parental clone. Parental clone is bolded. 1HH: Hollow Heart. Number of tubers out of 40 cut. 2CHIP SCORE: Snack Food Association Scale (Out of the field, 9/13/02); Ratings: 1-5; 1: Excellent, 5: Po 2001: Planted May 1, 2001; Harvested September 27, 2001 (150 DAYS) 2002: Planted May 1, 2002; Harvested September 11, 2002 (133 DAYS) Table 4B. 2001 and 2002 AGPase SIMULATED BLACKSPOT BRUISE SUSCEPTIBILITY TEST 2001 NUMBER OF SPOTS PER TUBER 0 5+ 1 2 3 4 PERCENT (%) AVERAGE SPOTS PER BRUISE FREE TUBER 2002 NUMBER OF SPOTS PER TUBER 0 5+ 3 4 2 1 PERCENT (%) AVERAGE SPOTS PER BRUISE FREE TUBER 17 5 5 2 16 15 16 11 4 2 4 7 8 2 1 8 9 6 8 4 2 1 1 5 9 4 1 1 2 4 6 6 3 3 5 2 2 3 3 3 3 2 1 1 1 2 4 1 2 15 7 10 10 68 20 20 8 64 60 64 44 16 8 16 ONAWAY 0.36 1.76 2.12 3.76 MSE149-5Y 0.40 0.44 0.56 0.88 2.56 3.24 3.28 12 4 4 5 20 12 24 21 2 5 9 5 7 4 3 8 1 1 2 1 4 9 4 3 2 3 3 6 1 8 1 4 5 1 8 9 5 6 3 7 6 11 3 3 1 1 1 4 3 48 16 16 20 80 48 96 84 8 0 20 0.680 2.240 2.160 2.560 0.280 0.840 0.040 0.280 2.880 4.000 2.360 LINE ONAWAY ONAGP2 * ONAGP1 * ONAGP3 * EAGP15 EAGP8 E149-5Y EAGP20 EAGP9 * EAGP4 * EAGP24 * Simulated bruise samples were prepared as follows: twenty-five A-size tuber samples were collected at harvest, held at 50 F at least 12 hours, placed in a six-sided plywood drum, and rotated ten times to produce simulated bruising. Samples were abrasive-peeled and scored on October 29, 2001 and October 24, 2002. The table is presented in 2001 ascending order of average number of spots per tuber. Parental clone is bolded. *These transgenic lines had higher solids than their non-transgenic parental line. Funding: Fed. Grant/MPIC 2002 POTATO VARIETY EVALUATIONS D.S. Douches, J. Coombs, L. Frank, J. Driscoll, K. Zarka, C. Long R. Hammerschmidt and W. Kirk Departments of Crop and Soil Sciences and Plant Pathology Michigan State University East Lansing, MI 48824 Each year we conduct a series of variety trials to assess advanced potato selections from the Twelve field experiments were conducted at the Montcalm Research Farm in Entrican, MI. INTRODUCTION Michigan State University and other potato breeding programs. The objectives of the evaluations are to identify superior varieties for fresh market or for processing and to develop recommendations for the growing of those varieties. The varieties were compared in groups according to the tuber type and skin color and to the advancement in selection. Each season, total and marketable yields, specific gravity, tuber appearance, incidence of external and internal defects, chip color (from field, 42°F and 50°F storage), as well as susceptibilities to late blight (foliar and tuber), common scab, Fusarium dry rot, and blackspot bruising are determined. PROCEDURE They were planted as randomized complete block designs with four replications. The plots were 23 feet long and spacing between plants was 12 inches. Inter-row spacing was 34 inches. Supplemental irrigation was applied as needed. This year the fields were fumigated in the fall prior to the field season. harvested at two dates (Date-of-Harvest trial: Early and Late). The other field experiments were the Long White and Russet, North Central Regional, Yellow Flesh, Adaptation (tablestock and chip- processors), Preliminary (tablestock and chip-processors) and Frito Lay trials. In each of these trials, the yield was graded into four size classes, incidence of external and internal defects in > 3.25 in. diameter or 10 oz. potatoes were recorded, and samples for specific gravity, chipping, disease tests, bruising, and cooking tests were taken. Chip quality was assessed on 25-tuber samples, taking two slices from each tuber. Chips were fried at 365°F. The color was measured visually with the SFA 1-5 color chart. Tuber samples were also stored at 42°F and 50°F for chip-processing out of storage in January and March. Advanced selections are also placed in the Commercial Demonstration Storage for monthly sampling. The scab nursery at the MSU Soils Farm and the late blight trial at the Muck Soils Research Farm are used for scab and foliar late blight assessment of lines in the agronomic trials. The round white tuber types were divided into chip-processors and tablestock and were There were 15 entries that were evaluated at two harvest dates. Atlantic, Snowden and Pike RESULTS A. Round White Varieties: Chip-processors (Tables 1 and 2) were used as checks. The plot yields were below average in the early harvest (97 days), and most lines increased between 60-200 cwt/a in yield for the second harvest date (144 days). The results are summarized in Tables 1 and 2. Tuber specific gravity readings were significantly below average for 2002. For example, Atlantic and Snowden had specific gravity readings of 1.079 and 1.075, respectively, in the late harvest. In the early harvest trial, MSI002-3 had the highest yield, while Atlantic, MSH095-4, B0766-3, MSF373-8 and W1201 were similar in yield behind MSI002-3. At the later harvest, many of the same lines were among the top yielding lines along with MSE018-1. These top yielding lines were also classified as blackspot bruise susceptible in the simulated bruise test. MSF099-3, W1201 and B0766-3 were also the top yielding lines in the on-farm processing trials. MSJ461-1 is a promising chip-processing line with strong foliar resistance to late blight. MSF373-8 continues to be a high yielding line with a significantly higher percentage of large tubers (62% oversize), and it chip-processes well out of the field. A Canadian group is interested in licensing MSF373-8 as a tablestock line. The scab level in the agronomic trial was high and scab ratings were collected in addition to the scab nursery. Liberator, Pike and MSG227-2 continue to be the lines with the highest scab resistance along with chip-processing ability. Chip-processing quality was high among all the entries in the out-of-the-field samples. Snowden, W1201, B0766-3, Liberator and MSF099-3 are in the 500 cwt bins of the Commercial Demonstration Storage. Incidence of internal defects was generally low, but Atlantic had a higher frequency of hollow heart in both early and late harvests. Variety Characteristics LIBERATOR - a MSU selection for chip-processing with strong scab resistance. Yield and specific gravity over the past five years were comparable to Snowden. It has performed well in other states (Nebraska, Pennsylvania and California). It was in the national SFA and the North Central regional trials. Liberator was released in 2001 and is in the 2002 Commercial Demonstration Storage. MSF099-3 – a MSU chip-processing selection. It has high specific gravity, smooth attractive tubers, and excellent chip quality and will chip-process from 45°F cold storage. In 2000 it was one of the best chip-processors in the 42°F MPIC demonstration storage. It yielded well on the on-farm trials, but the large tubers tended to elongate. It is also scab susceptible. MSF099-3 has been put in the 2001 and 2002 Commercial Demonstration Storage 500 cwt. bins. MSG227-2 – a MSU chip-processing selection with strong scab resistance. It has a specific gravity acceptable for chip-processing, excellent chip quality and cold-chipping potential. The tubers are smooth-shaped with a flattened round appearance that is attractive. It has chip-processed well from the 42°F MPIC demonstration storage studies. This line will be considered for release in 2003. MSH094-8 - a new chip-processing selection with cold-chipping potential from 42ºF storage. This line also has a low incidence of internal defects and mid-season maturity. It will in on-farm trials in 2002. MSH095-4 - a mid-season maturing line with excellent chip quality and bruise susceptibility equal to Snowden. It was comparable to Atlantic for yield and solids at the Montcalm Research Farm. It was in the on-farm trials for 2001-2002. MSF373-8 - a high yielding selection with acceptable specific gravity for chip-processing. It will chip out-of-the-field and from 50°F storage. Produces large tubers with a low incidence of internal defects. Scab tolerance is intermediate. MSE018-1 - a very high yield potential, high specific gravity selection with moderate tolerance to scab. It has a late maturity, large vine and some reduced susceptibility to late blight. Tuber appearance is bright and smooth with a round-oval shape. It has chip-processed well in May and June from the Commercial Demonstration Storage the past two years. MSJ461-1 – an exciting, new MSU chip-processing selection with strong foliar resistance to late blight, and maturity similar to Snowden. It has excellent chip-processing quality, smooth round shape and average yield, but an intermediate specific gravity. MSI002-3 – a new MSU selection with high yield and high solids potential. It was in a few on- farm trials in 2002. It is a progeny of Liberator, but it does not have a high level of scab resistance. B0766-3 – a selection from USDA-Beltsville. It has high yield potential and scab tolerance along with excellent chip-processing quality. It is in one of the 500 cwt 2002 Commercial Demonstration Storage bins. W1201 – a selection from Wisconsin that has high solids, chip-processing quality and high yield potential. The large tubers tend to sheep nose. It is in one of the 500 cwt 2002 Commercial Demonstration Storage bins. B. Round White Varieties: Tablestock (Tables 3 and 4) The plot yields were average in the early harvest (97 days), and a moderate yield increase was observed for the second harvest date (132 days). Tuber specific gravity readings were below average. The results are summarized in Tables 3 and 4. In the early harvest trial, Onaway, Michigan Purple, MSE221-1 and MSH031-5 were the top yielding lines. There was very little incidence of internal defects in the early harvest. In the later harvest, Onaway, MSH031-5, MSI152- A, and Michigan Purple were the top yielding lines. Overall, incidence of internal defects was low in comparison to previous years. MSE221-1 and Onaway were the only lines to classify as scab tolerant. MSE221-1 and Jacqueline Lee had above average bruising in the simulated bruise tests. Another strong performing line is Michigan Purple, which was released in 2001, that has a bright purple skin and excellent internal quality. Jacqueline Lee, a smooth, bright-skinned, yellow-flesh variety with strong resistance to foliar late blight and maturity equal to Snowden, was also released There were 9 entries that were evaluated at two harvest dates. Onaway was used as a check. JACQUELINE LEE – an MSU oval/oblong tablestock selection with a high tuber set. The in 2001. MSI152-A is a high yielding, round white line with foliar resistance to late blight, however, the maturity is full season. Variety Characteristics tubers have the bright skinned, smooth and attractive appearance that is typical of many European cultivars. The tubers have very low incidence of internal defects and good baking quality. The strength of this selection is its strong foliar resistance to the US8 genotype of late blight. Vine maturity is similar to Snowden. MICHIGAN PURPLE - a tablestock selection with an attractive purple skin. This selection has high yield potential and the tubers have a low incidence of internal defects. The vine maturity is mid-season to mid-early. We regard this as a variety that can compete in the red market. MSH031-5 – a MSU tablestock/chip selection with high yield potential, attractive round shape and bright skin. It has also performed well in North Carolina. It is scab susceptible. MSE221-1 - a MSU tablestock selection. It has high yield potential as seen in the MSU and on- farm trials. General appearance is good, but it has a netted appearance similar to Superior. It has strong resistance to scab. It is being considered for release in 2002. MSG004-3 - a MSU tablestock selection. It has average yield potential and produces bright attractive tubers with good internal quality. C. Long Whites and Russet Varieties (Table 5) The long white and russet trial had 14 lines evaluated in 2002. GoldRush, Russet Burbank and Russet Norkotah were the standard varieties in the trial and the results are summarized in Table 5. Scab resistance was prevalent among the lines tested. Internal quality was high except for A8893- 1RUS and CO92077-2RUS. Specific gravity measurements were well below average with Russet Burbank having a 1.063 reading. The three standards were very low yielding in the trial. The yield of the overall trial was below average for 2002, however, Keystone Russet was the highest yielding line by over 170 cwt/A. All lines were chip-processed out of the field with NDC5372-1RUS and TC1675-1RUS having excellent color. Variety Characteristics MSB106-7 - a MSU tablestock selection. It has high yield potential as seen in the on-farm trials, but performed poorly at MSU. Tubers are oblong-long with a light netting. Internal quality is excellent and it has a very white flesh. MSE192-8RUS - a MSU tablestock selection. The tubers have an attractive russeting and shape. The vine is small which may make this line uncompetitive in small plot trials. The tuber type suggests that it be considered a replacement for Russet Norkotah. The tubers have a white flesh that The North Central Trial is conducted in a wide range of environments (11 locations) to provide does not darken after cooking. It has performed well in taste tests. MSE202-3RUS – a MSU dual-purpose russet selection. It has a late maturity and high yield potential. Its specific gravity is equivalent to Russet Burbank and the tubers are long with a lighter, but attractive russet skin. Scab resistance is also high. Frito Lay is testing MSE202-3RUS as a directional chipper. D. North Central Regional Trial (Table 6) adaptability data for the release of new varieties from North Dakota, Minnesota, Wisconsin, Michigan and Canada. Twenty-four breeding lines and seven varieties were tested in Michigan. The results are presented in Table 6. The range of yield was wide and specific gravities of the lines were very low in 2002. The MSU lines MSE018-1, MSE221-1, MSE202-3RUS and MSF313-3 were all included in the North Central Trial for the first time in 2002. ND2470-27 was the highest performing line and chip-processed out of the field. ND5822C-7 was also high yielding, but was susceptible to hollow heart. This line also has some Colorado potato beetle resistance. NY112 is a promising line that is being released by Cornell University, but has shown susceptibility to blackspot bruise. The top-rated red-skinned line was ND5084-3R when you consider yield, shape, red color and internal defects. MSE221-1, a scab resistant MSU tablestock selection, was also a promising selection in the trial. The top-rated russet line was W1836-3Rus, but in general, the russet varieties and lines performed below average. E. Yellow Flesh Trial (Table7) were used as checks. The results are summarized in Table 7. The trial was harvested after 145 days, and yields were below average and varied considerably. The best yielding lines in 2002 were MSJ033-10Y, MSI005-20Y, MSJ453-4Y, and MSE149-5Y. These results were similar to 2001. Internal defects and late vine maturity make MSJ453-4Y, a late blight resistant selection, undesirable at the commercial level. MSI005-20Y was a strong overall performing line with high yield, excellent internal quality, and medium-early maturity. Torridon and MSJ459-2Y also have foliar late blight resistance, but are scab susceptible, late maturing and suffer from internal defects. Some entries were evaluated for chip-processing quality out-of-the-field and MSE149-5Y, Saginaw Gold and MSJ453-4Y had acceptable chip color. The high incidence of internal brown spot in Torridon was observed in both 2001 and 2002. F. Adaptation Trial (Tables 8A and 8B) (Snowden and Atlantic) and 26 advanced breeding lines are reported in the chip-processing trial. The trial was harvested after 146 days and the results are summarized in Table 8A. The high yielding lines identified in 2002 were W2062-1, B1240-1, MSJ167-1 and A91790-13, but these lines were also the later-maturing selections. In addition, these lines were classified as blackspot bruise susceptible in the simulated bruise test. As in all the 2002 trials, the specific gravity readings were below average, but W2062-1, MSJ167-1, MSH112-6 and W1980-4 had readings higher than Eleven varieties and advanced selections were tested in 2002. Yukon Gold and Saginaw Gold The Adaptation trial was divided into chip-processing and tablestock trials. Two cultivars In the tablestock trial Onaway and Superior were the check varieties and 17 advanced breeding The Preliminary trial is the first replicated trial for evaluating new advanced selections from the Atlantic. Other lines of interest were observed. MSH067-3 is a chip-processing selection with cold- chipping potential. It has mid-season maturity and intermediate scab tolerance. The tubers are flattened and round. MSJ456-4 and MSJ319-1 have strong foliar late blight resistance. Based upon two years of study, MSH228-6, MSJ126-9Y and MSH356-A showed some scab tolerance. lines and new varieties were evaluated. The trial was harvested after 139 days and the results are summarized in Table 8B. Eight red-skinned entries were compared. Mazama was the top yielding line, but the red skin color was not strong. Durango Red and NDTX4271-5R had the best combination of shape and red skin color. Among the red lines, internal defects were low except for the vascular discoloration in Mazama and CO89097-2RED. ATX85404-8W was the highest yielding line, but has some hollow heart susceptibility. MSJ317-1 is a round white selection with a bright skin that has strong foliar resistance to late blight, but the vine maturity is very late. MSJ319- 7 and MSJ307-2 also have late blight resistance, but the tuber type is not as desirable. Scab tolerance was limited to Superior, Onaway, Cal Red and Mazama. Interestingly, no entries were classified as blackspot bruise susceptible. H. Preliminary Trial (Tables 9A and 9B) MSU potato breeding program. Twenty-nine advanced selections and three check varieties were tested and reported in two separate Preliminary trials. The division of the trials was based upon chip-processing or tablestock utilization. The chip-processing trial is summarized in Table 9A. The top yielding line was MSJ316-A and was also classified as scab resistant. Another promising line is MSK061-4 which has a high percentage of uniformed A-sized tubers. Other scab tolerant lines identified in this trial are MSK498-1Y, MSK476-1, NY120, MSH015-2, and MSG301-9. Internal defects were generally low in the trial with Atlantic showing the greatest susceptibility to hollow heart. Blackspot bruise susceptibility was also low in this trial. Table 9B summarizes the results from the Preliminary tablestock trial. Harvest was completed after 134 days. No late blight resistant lines were among the chip processors, but 5 entries in the tablestock trial had strong foliar resistance to late blight. Of those, MSL757-1 shows the most promise. It has above average yield potential, an attractive blocky oval shape and above average solids. MSK125-3 is from has a late blight pedigree, but is not highly resistant. However, it has high yield and attractive smooth tubers. Silverton Russet was an attractive, scab resistant russet variety that had nice russet type among the A-sized tubers. Other scab resistant lines are MSK217- 3P, MSJ036-A, MSK247-9Y and MSK004-AY. I. Frito Lay Trial (Table 10) A separate trial was conducted with the three major Frito Lay varieties because of the late arrival of the seed. It was planted about two weeks later than our other agronomic trials. For comparison Snowden, Atlantic and Liberator were included in the trial. Chip-processing out of the field was acceptable for all varieties. For US#1 yield, no differences existed among the varieties. FL1867 and Liberator had the highest total yields, while Atlantic and Liberator had the highest specific gravity readings. Atlantic and FL1833 were most susceptible to hollow heart in the oversize tubers. Each year a replicated field trial at the MSU Soils Farm is conducted to assess resistance to Liberator and FL1833 had little scab incidence compared to the other varieties. Blackspot bruise was low in this trial. J. Potato Scab Evaluation (Table 11) common and pitted scab. For the second year, we are using a modified scale of a 0-5 ranking based upon a combined score for scab coverage and lesion severity. Usually examining one year's data does not indicate which varieties are resistant but it should begin to identify ones that can be classified as susceptible to scab. Our goal is to evaluate important advanced selections and varieties in the study at least three years to obtain a valid estimate of the level of resistance in each line. Table 11 categorizes many of the varieties and advanced selections tested in 2002 at the MSU Soils Farm Scab Nursery. This disease trial is a severe test. The varieties and lines are placed into six arbitrary categories based upon scab infection level and lesion severity. A rating of 0 indicates zero infection. A score of 1.0 indicates a trace amount of infection. A moderate resistance (1.2 – 1.8) correlates with <10% infection. Scores of 4.0 or greater are found on lines with >50% infection and severe pitted lesions. In 2002 the scab disease incidence at the nursery was typical compared to other years, and the data were separated into three categories (Resistant = 0.0-1.2; Moderately Resistant = 1.3 – 1.70; and Susceptible = 2 or higher).The check varieties Russet Burbank, GoldRush, Superior, Onaway, Pike, Red Pontiac, Yukon Gold, Atlantic and Snowden can be used as references (bolded in Table 11). This year’s results indicate that we have been able to breed numerous lines for the chip-processing and tablestock markets with resistance to scab. Most notable scab resistant lines are Liberator, MSG227-2, MSE192-8RUS, MSE202-3RUS, MSE221-1, MSG301-9, MSH228-6, MSJ126-9Y, MSH015-2, MSJ316-A and MSJ036-A. Scab results from the disease nursery are also found in the Trial Summaries (Tables 2, 4-10). K. Late Blight Trial (Table 12) entries were evaluated in replicated plots. The field was planted on 7 June and inoculated 26 July with isolates 94-3, 95-7, 98-2, and 00-1, and ratings were taken throughout August. Most lines were highly susceptible to the US-8 genotype of late blight. Included in this trial are the varieties and lines from the MSU trials at the Montcalm Research Farm and lines from the National Late Bight Variety Trial. The results are summarized in Table 12. Lines with the least infection from multi- year testing have been LBR8, LBR9, A90586-11, Jacqueline Lee, MSJ461-1, B0767-2, B0692-4, B0718-3, AWN86514-2 and Torridon (a Scottish variety). Jacqueline Lee has demonstrated strong late blight resistance over the past six years. In addition, many new MSU selections were in this top tier. Included in this group are MSJ453-4Y, MSJ456-4, MSJ456-2 and MSJ457-2 which all are progeny of Tollocan; MSJ307-2, MSJ319-1, MSJ317-2, MSI152-A and MSJ319-7 which are progeny of B0718-3. We also have progeny of Jacqueline Lee with strong late blight resistance: MSK106-A, MSK106-B, MSK101-2 and MSK128-2. These resistant progeny indicate that we can continue to breed for resistance using Jacqueline Lee as a parent. Some of the promising new selections for resistance are MSL766-1, MSL757-1, MSL211-3, MSK027-C, MSK034-1 and MSK136-2. We find these late blight resistant lines valuable because many of them also have marketable maturity. Many of these lines also have other desirable traits such as scab tolerance resistance and/or chip-processing quality. Tuber late blight resistance is being evaluated on many of In 2002, a late blight trial was conducted at the Muck Soils Research Farm. Over 160 Increased evaluations of advanced seedlings and new varieties for their susceptibility to the selections with foliar late blight resistance. L. Blackspot Susceptibility (Table 13) blackspot bruising have been implemented in the variety evaluation program over the past decade. Based upon the results collected over the past three years we decided to eliminate the check sample from our bruise assessment. Therefore a composite bruise sample of each line in the trials was collected. The sample consisted of 25 tubers (a composite of 4 reps) from each line at the time of grading. The 25 tuber sample was held in 50°F storage overnight and then was placed in a hexagon plywood drum and tumbled 10 times to provide a simulated bruise. The samples were peeled in an abrasive peeler in October and individual tubers were assessed for the number of blackspot bruises on each potato. These data are shown in Table 13. The bruise data are represented in two ways: percentage of bruise free potatoes and average number of bruises per tuber. A high percentage of bruise-free potatoes is the desired goal; however, the numbers of blackspot bruises per potato is also important. Cultivars which show blackspot incidence greater than Atlantic are approaching the bruise-susceptible rating. In addition, the data is grouped by trial, since the bruise levels can vary between trials. Conducting the simulated bruise on 50°F tubers is helping to standardize the bruise testing. We are observing less variation between trials since we standardized the handling of the bruise sample. However, these results become more meaningful when evaluated over 3 years that reflects different growing seasons and harvest conditions. In 2002 the bruise levels were lower than other years. This may be attributed to the lower solids observed in the tubers. The most bruise resistant lines this year were MSF099-3, MSG227-2, MSH031-5, MSF313-3, MSE202-3RUS, MSE192-8RUS, MSJ033-6Y, MSI005-20Y, AC87340-2W, A90490-1, MSH228-6, Cherry Red, MSI049-A, Durango Red, NDTX4271-5R, MSK061-4, MSK125-3 and most of the russet lines. The most susceptible lines were MSH095-4, MSE018-1, Torridon, W2062-1, NDTX4930-5W and NY120. M. Post-harvest Disease Evaluation: Fusarium Dry Rot As part of the post harvest evaluation, resistance to Fusarium sambucinum (Fusarium dry rot) was assessed by inoculating 3 whole tubers post-harvest from selected lines and varieties in the 2002 MRF variety trials. The tubers were held at 20°C (room temperature) for approximately three weeks post inoculation with Fusarium mycelial plugs and then scored for dry rot infection depth and width. A total of 104 breeding lines and varieties were tested. Overall the mean infection depth of the lesion ranged from 0.6-15.9 mm with an LSD0.05 = 6.2 mm. The 2002 infection level was about 50% of the 2001 infection level. In the previous two years we classified Superior, GoldRush, NorValley, Liberator and Michigan Purple in the tolerant group. In 2001, MSH067-3 also had a low infection level. The 2002 results concur. Table 14 lists many additional lines in the 2002 are classified as having low infection level. Also consistent with the 2001 data, the varieties classified as susceptible in the 2002 evaluation were Atlantic and Pike. At this time, complete resistance to Fusarium dry rot has not been found in the cultivated germplasm, but genetic variation for tolerance to dry rot does exist. N. Seed Availability of MSU New Varieties and Advanced Selections The MSU Potato Breeding program has entered a new stage of development as we have released the first three potato varieties and have numerous lines with commercial potential. These lines are in tissue culture and have greenhouse tuber production and in many cases there is field generation seed available. Table 15 summarizes the current seed available of the new MSU varieties and advanced selections. Table 1 MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS ROUND WHITE CHIP POTATOES: EARLY HARVEST MONTCALM RESEARCH FARM AUGUST 6, 2002 (97 DAYS) LINE US#1 TOTAL US#1 Bs As OV PO SP GR CWT/A PERCENT OF TOTAL1 CHIP SCORE3 HH VD IBS BC TUBER QUALITY2 TOTAL CUT MSI002-3 ATLANTIC MSH095-4 B0766-3 MSF373-8 W1201 LIBERATOR MSE018-1 MSF099-3 MSJ461-1 LBR SNOWDEN MSH094-8 MSG227-2 PIKE MSI083-5 MEAN LSD0.05 311 264 257 251 241 238 216 215 211 196 195 193 176 169 159 219 32 347 295 281 267 249 261 243 246 246 252 234 216 222 207 190 250 33 89 90 91 94 97 91 89 87 85 78 83 89 79 81 84 10 8 6 6 1 7 10 12 13 22 16 11 19 19 15 86 85 80 91 66 88 86 81 83 77 83 88 79 81 83 4 5 11 3 32 3 3 6 2 0 1 1 0 0 1 0 3 3 0 2 1 2 0 1 0 1 0 2 0 1 1.078 1.079 1.076 1.073 1.068 1.076 1.076 1.074 1.077 1.065 1.075 1.074 1.070 1.073 1.069 1.074 0.002 1.0 1.5 1.0 1.0 1.5 1.0 1.0 1.0 1.0 1.5 1.0 1.0 1.5 1.0 1.0 5 12 1 3 0 3 1 4 1 0 1 1 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 3-YR AVG US#1 CWT/A - 342 300* - 344 - 276 309 254 200* 252 291 282 232 - * Two-Year Average LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials in 2002 at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. Planted May 1, 2002 Table 2 LINE MSE018-1 MSF373-8 B0766-3 MSI002-3 W1201 ATLANTIC MSH095-4 MSF099-3 MSH094-8 MSJ461-1 LBR LIBERATOR PIKE SNOWDEN MSG227-2 MSI083-5 MEAN LSD0.05 438 392 390 376 364 328 326 323 299 279 276 262 262 256 255 322 53 470 401 407 420 391 352 351 348 324 330 309 302 304 326 288 355 50 93 98 96 90 93 93 93 93 92 84 89 87 86 78 89 5 1 4 10 5 5 5 6 7 15 7 13 13 12 10 74 36 77 84 84 81 77 83 88 84 80 86 81 74 85 19 62 19 5 9 12 16 10 4 0 9 1 5 4 3 1 1 0 0 2 1 2 1 1 0 4 0 0 10 1 1.079 1.072 1.072 1.077 1.081 1.078 1.076 1.076 1.075 1.069 1.074 1.077 1.073 1.072 1.072 1.075 0.002 1.5 1.5 1.0 1.5 1.5 1.5 1.0 1.5 1.5 1.0 1.5 1.0 1.0 1.0 2.0 8 4 4 2 0 11 1 2 0 0 1 0 3 0 0 2 0 3 0 5 1 2 0 0 0 0 0 4 1 0 0 0 0 1 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 1 0 2 0 0 ROUND WHITE CHIP POTATOES: LATE HARVEST MONTCALM RESEARCH FARM SEPTEMBER 23, 2002 (144 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 CHIP TUBER QUALITY2 TOTAL NURSERY TRIAL US#1 TOTAL US#1 Bs As OV PO SP GR SCORE3 HH VD IBS BC SCAB4 SCAB4 MAT5 BRUISE6 CUT 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 SUSC. SUSC. SUSC. SUSC. SUSC. SUSC. 3.6 2.5 1.5 4.0 1.3 2.7 2.0 3.7 2.3 2.7 0.0 1.1 2.0 0.5 3.3 1.6 1.1 0.1 1.9 0.5 0.9 0.4 1.1 0.9 2.0 0.0 0.6 1.1 0.0 2.8 3.9 3.0 2.8 1.9 3.3 2.5 2.5 2.4 2.3 3.0 2.5 2.5 2.5 2.9 2.8 3-YR AVG US#1 CWT/A 438 457 - - - 398 385* 329 366 289* 358 317 343 366 - * Two-Year Average LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials in 2002 at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3CHIP SCORE: Snack Food Association Scale (Out of the field, 9/25/02); Ratings: 1-5; 1: Excellent, 5: Poor. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: Taken August 21, 2002; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) 6BRUISE: These lines demonstrated blackspot bruise susceptibility in simulated bruise testing in 2002. Planted May 2, 2002 Table 3 LINE MSE221-1 MSH031-5 MICHIGAN PURPLE ONAWAY MSE080-4 MSF313-3 MSG004-3 JACQUELINE LEE LBR MSI152-A LBR MEAN LSD0.05 ROUND WHITE TABLESTOCK POTATOES: EARLY HARVEST MONTCALM RESEARCH FARM AUGUST 6, 2002 (97 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV PO SP GR HH VD IBS BC TUBER QUALITY2 TOTAL CUT 360 286 283 256 247 183 181 179 135 234 41 381 324 311 291 260 239 192 307 170 275 48 94 88 91 88 95 76 95 58 80 3 12 5 9 5 23 4 39 19 82 88 83 79 89 76 90 58 80 13 0 8 9 6 1 4 0 0 3 0 4 3 0 1 1 3 2 1.063 1.074 1.063 1.059 1.067 1.070 1.057 1.069 1.058 1.064 0.003 0 0 1 0 0 0 1 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 40 40 40 40 40 40 40 40 40 3-YR AVG US#1 CWT/A 397 346 341* 388 - 226 238 187 - * Two-Year Average LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials in 2002 at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Planted May 1, 2002 Table 4 MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS ROUND WHITE TABLESTOCK POTATOES: LATE HARVEST MONTCALM RESEARCH FARM SEPTEMBER 11, 2002 (132 DAYS) LINE US#1 TOTAL US#1 Bs As OV PO SP GR HH VD IBS BC CUT SCAB3 SCAB3 MAT4 BRUISE5 CWT/A PERCENT OF TOTAL1 TUBER QUALITY2 TOTAL NURSERY TRIAL 3-YR AVG US#1 CWT/A 397 MSE221-1 341 MICHIGAN PURPLE 334 MSH031-5 MSI152-A LBR 309 294 ONAWAY 249 MSF313-3 239 MSE080-4 MSG004-3 225 JACQUELINE LEE LBR 220 MEAN LSD0.05 290 47 418 355 365 345 321 293 256 241 360 328 48 95 96 91 90 92 85 93 93 61 3 3 9 9 6 14 6 5 38 84 81 91 84 83 84 85 83 61 11 16 1 6 9 1 8 11 0 2 1 0 2 2 1 0 2 1 1.063 1.066 1.074 1.061 1.060 1.070 1.067 1.058 1.075 1.066 0.002 3 2 0 4 0 0 0 0 0 1 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 40 40 40 40 40 40 40 40 40 1.3 2.7 2.3 2.0 1.7 2.3 1.7 1.5 2.7 1.0 2.5 2.8 2.0 1.3 2.8 2.0 1.8 2.0 1.3 1.6 2.0 3.1 1.3 3.0 1.5 2.5 2.6 SUSC. SUSC. 412 331* 363 - 412 282 - 275 276 * Two-Year Average LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials in 2002 at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 4MATURITY RATING: Taken August 21, 2002; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) 5BRUISE: These lines demonstrated blackspot bruise susceptibility in simulated bruise testing in 2002. Planted May 2, 2002 Table 5 LINE LONG WHITE and RUSSET TRIAL MONTCALM RESEARCH FARM SEPTEMBER 9, 2002 (132 DAYS) CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV PO SP GR SCORE3 HH VD IBS BC CHIP TUBER QUALITY2 TOTAL CUT MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS 3-YR AVG US#1 SCAB4 MAT5 BRUISE6 CWT/A 488 KEYSTONE RUSSET 310 A8893-1RUS 287 AC92009-4R 265 MSE202-3RUS 256 AC89536-5RUS 231 NDC5372-1RUS 224 CO92077-2RUS 217 MSB106-7 214 CO85026-4 212 MSE192-8RUS 201 GOLDRUSH 181 RUSSET BURBANK TC1675-1RUS 172 RUSSET NORKOTAH 106 MEAN LSD0.05 240 52 549 404 345 344 362 353 291 308 271 326 299 291 297 231 334 55 89 77 83 77 71 65 77 70 79 65 67 62 58 46 9 19 10 17 28 33 21 19 15 33 27 27 40 54 56 63 63 67 65 64 66 61 62 59 61 54 55 43 33 14 20 10 6 2 11 10 17 6 6 8 3 3 2 4 7 6 1 2 2 11 6 2 6 10 2 1 1.057 1.067 1.077 1.071 1.076 1.077 1.058 1.055 1.074 1.064 1.056 1.063 1.075 1.058 1.066 0.005 2.0 2.0 2.0 2.5 2.0 1.0 2.0 - 1.5 2.0 2.5 2.0 1.0 2.0 0 15 1 4 5 4 0 0 1 0 0 2 1 1 6 6 1 0 1 0 0 2 0 4 1 1 3 3 0 0 0 0 1 0 5 0 0 0 0 1 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 40 40 40 40 40 40 40 40 40 40 40 40 40 40 0.5 0.0 0.0 0.0 0.0 1.0 1.5 1.0 0.7 0.3 0.3 1.0 0.7 1.2 3.5 2.6 3.3 3.4 3.3 3.9 3.0 1.3 3.5 1.6 1.8 1.9 3.1 1.3 SUSC. SUSC. - 356 - 371 265* - - 294 224* 252 228* 242 - 214 * Two-Year Average 1SIZE: B: < 4oz.; A: 4-10oz.; OV: > 10oz.; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3CHIP SCORE: Snack Food Association Scale (Out of the field, 9/13/02); Ratings: 1-5; 1: Excellent, 5: Poor. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: Taken August 21, 2002; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering). 6BRUISE: These lines demonstrated blackspot bruise susceptibility in simulated bruise testing in 2002. Planted May 1, 2002 Table 6 ENTRY NORTH CENTRAL REGIONAL TRIAL MONTCALM RESEARCH FARM SEPTEMBER 9, 2002 (131 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV PO SP GR SCORE3 HH VD IBS BC CUT SCAB4 MAT5 BRUISE6 MERIT7 CHIP TUBER QUALITY2 TOTAL 524 509 463 406 400 398 381 376 373 365 347 340 339 320 318 314 291 287 279 263 263 247 235 224 ND2470-27 ND5822C-7 NY112 ND5084-3R MSE018-1 MSE221-1 W1386 MN18710Rus D.R. NORLAND ATLANTIC W1201 W1431 B0766-3 SNOWDEN MN19525R W1836-3Rus CV89023-2R MSE202-3Rus NORVALLEY RED PONTIAC A9014-2Rus MSF313-3 MN18747Rus A90586-11RusLBR continued on following page: 567 548 479 427 428 414 403 407 410 393 369 364 360 394 353 394 350 363 324 314 308 299 266 320 92 93 97 95 94 96 94 92 91 93 94 93 94 81 90 80 83 79 86 84 85 83 88 70 7 7 3 3 5 3 5 7 9 7 5 5 6 19 9 16 16 16 11 7 13 17 11 27 87 85 88 67 73 84 84 67 91 91 84 81 90 81 80 73 83 74 85 74 52 82 84 69 5 7 8 28 20 12 10 25 0 2 10 12 5 0 10 7 0 5 1 10 33 0 5 2 1 1 0 1 1 1 1 1 0 1 1 1 0 0 0 4 1 4 3 9 1 0 1 3 1.068 1.080 1.070 1.055 1.076 1.061 1.074 1.068 1.052 1.077 1.081 1.078 1.072 1.074 1.061 1.071 1.063 1.071 1.067 1.055 1.072 1.070 1.056 1.073 1.0 1.5 1.0 2.5 1.5 1.5 1.0 2.5 2.0 1.5 1.0 1.0 1.0 1.0 3.0 2.0 2.5 2.5 1.0 3.0 1.0 1.5 1.0 2.0 0 17 0 0 2 3 4 0 0 3 1 24 1 0 0 6 0 12 0 4 15 0 0 0 1 0 2 0 2 2 0 0 0 0 4 0 0 2 1 0 0 0 1 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 2 0 0 0 0 0 0 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 3.0 2.7 1.3 2.0 3.6 1.3 2.3 0.0 2.7 1.3 2.8 1.5 2.0 2.0 1.0 0.0 2.0 0.0 2.0 3.0 0.3 2.3 - 3.5 2.8 3.1 2.6 3.1 3.6 1.3 2.3 3.4 1.3 1.9 3.3 2.9 2.8 2.1 2.4 2.9 1.0 2.5 1.9 3.6 3.6 2.9 1.1 2.4 1W SUSC. SUSC. 2W 1RD SUSC. 4W 3W SUSC. 2RD 5W 4RD 1RUS 3RD 2RUS 3RUS SUSC. SUSC. SUSC. NORTH CENTRAL REGIONAL TRIAL MONTCALM RESEARCH FARM SEPTEMBER 9, 2002 (131 DAYS) ENTRY CWT/A US#1 TOTAL PERCENT OF TOTAL1 US#1 Bs As OV CHIP TUBER QUALITY2 PO SP GR SCORE3 HH VD IBS BC TOTAL CUT SCAB4 MAT5 BRUISE6 MERIT7 continued: 218 ND3196-1R 206 MN15620LR RUSSET BURBANK 202 RUSSET NORKOTAH 162 141 V04981-1R V0498-9R 137 134 V0497-1 MEAN LSD0.05 171 70 239 266 285 245 172 160 157 218 69 91 77 71 66 82 86 85 7 19 17 33 10 4 13 82 73 66 64 82 77 80 9 4 5 2 0 9 5 2 4 12 1 8 10 2 1.055 1.069 1.064 1.060 1.045 1.049 1.064 1.058 0.003 3.0 1.0 2.5 2.0 3.5 1.5 1.0 0 1 6 1 0 0 1 0 5 0 2 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 40 40 40 40 10 40 40 0.7 2.0 1.0 1.2 - 2.0 3.5 1.0 3.6 2.6 1.1 1.0 1.5 1.6 5RD 5RUS 4RUS LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials in 2002 at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: Taken August 21, 2002; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering). 6BRUISE: These lines demonstrated blackspot bruise susceptibility in simulated bruise testing in 2002. 7MERIT: A Merit rating was given for the best 5 entries in each market class (rank order, 1 = best). Planted May 1, 2002 Table 7 LINE YELLOW FLESH and EUROPEAN TRIAL MONTCALM RESEARCH FARM SEPTEMBER 23, 2002 (145 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 CHIP TUBER QUALITY2 TOTAL NURSERY TRIAL US#1 TOTAL US#1 Bs As OV PO SP GR SCORE3 HH VD IBS BC SCAB4 SCAB4 MAT5 BRUISE6 377 MSI005-20Y 350 MSE149-5Y 325 MSJ033-10Y MSJ453-4Y LBR 318 SAGINAW GOLD 277 261 MSE048-2Y 260 MSJ033-6Y TORRIDON LBR 250 234 YUKON GOLD 185 MSJ459-2Y MSJ472-4P 164 MEAN LSD0.05 273 92 438 373 390 402 331 277 305 392 262 206 253 330 87 86 94 83 79 84 94 85 64 89 90 65 10 5 11 14 12 3 7 24 5 5 33 76 77 82 77 82 79 75 59 79 64 65 11 17 2 2 2 15 10 5 11 25 0 4 1 6 6 4 2 7 12 6 5 2 1.066 1.061 1.060 1.079 1.063 1.067 1.060 1.079 1.066 1.076 1.074 1.068 0.005 - 1.0 - 1.0 1.5 - - - - 1.0 2.0 0 2 0 5 0 1 0 0 0 3 1 2 0 3 2 0 0 9 1 5 6 0 0 1 0 13 0 5 0 23 0 3 0 0 0 0 1 0 4 0 0 0 1 0 CUT 40 40 40 40 40 40 40 40 40 40 40 2.0 1.3 1.0 2.7 1.0 1.5 2.0 4.3 4.0 2.5 2.0 1.9 1.3 0.6 2.3 1.4 1.8 1.6 5.1 2.8 2.1 1.8 3.5 2.5 2.8 4.1 1.1 3.4 2.9 3.6 1.0 4.6 2.3 SUSC. SUSC. SUSC. LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials in 2002 at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3CHIP SCORE: Snack Food Association Scale (Out of the field, 9/25/02); Ratings: 1-5; 1: Excellent, 5: Poor. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: Taken August 21, 2002; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) 6BRUISE: These lines demonstrated blackspot bruise susceptibility in simulated bruise testing in 2002. Planted May 1, 2002 Table 8A LINE ADAPTATION TRIAL, CHIP-PROCESSING LINES MONTCALM RESEARCH FARM SEPTEMBER 24, 2002 (146 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A TUBER QUALITY2 US#1 TOTAL US#1 Bs As OV PO SP GR SCORE3 HH VD IBS BC PERCENT OF TOTAL1 CHIP TOTAL NURSERY TRIAL CUT SCAB4 SCAB4 MAT5 BRUISE6 476 460 441 422 377 375 370 368 347 343 342 336 331 325 318 318 318 316 309 301 284 275 266 W2062-1 B1240-1 MSJ167-1 A91790-13 MSH228-6 MSH067-3 W1773-7 MSJ080-1 MSH112-6 MSJ147-1 W1980-4 ATLANTIC AC87340-2W DAKOTA PEARL MSJ197-1 MSH098-2 A90490-1 MSJ456-4 LBR MSJ319-1 LBR MSH360-1 MSJ126-9Y MSJ080-8 BC0894-2W continued on following page: 540 471 476 455 398 389 403 393 428 382 379 357 402 356 342 330 332 384 345 327 318 299 300 88 98 93 93 95 96 92 94 81 90 90 94 83 91 93 96 96 82 90 92 89 92 89 11 2 6 5 5 2 7 6 18 10 6 4 17 8 6 3 4 17 9 7 11 7 10 85 80 91 73 81 78 82 79 79 88 77 78 81 87 80 82 71 82 83 88 85 86 88 3 18 2 20 13 19 10 15 2 2 13 16 2 4 13 14 25 1 7 4 4 6 0 1 0 1 2 1 1 1 0 0 1 3 2 0 1 1 0 1 1 1 1 0 1 1 1.086 1.076 1.086 1.074 1.066 1.077 1.075 1.064 1.080 1.073 1.081 1.077 1.065 1.064 1.069 1.073 1.065 1.077 1.075 1.074 1.063 1.073 1.059 1.5 2.0 1.5 1.5 1.0 1.5 1.5 1.5 1.0 1.0 1.5 1.5 1.0 1.5 2.0 1.0 1.5 1.5 1.0 2.0 1.0 1.0 1.5 4 6 0 3 5 4 0 0 0 0 7 8 0 1 0 0 8 0 8 2 0 7 1 0 6 0 4 3 0 0 3 1 0 3 1 0 7 3 1 0 2 1 4 1 1 0 0 0 0 0 3 1 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 2 0 0 0 0 0 0 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 2.3 2.0 2.0 3.5 1.3 3.0 2.7 2.5 - 2.0 2.0 2.7 2.3 - 2.7 2.7 2.3 2.0 2.0 2.0 0.3 2.0 2.3 1.0 0.8 0.8 0.8 0.5 1.0 1.1 0.5 1.0 0.9 1.2 1.4 1.3 0.3 0.5 1.4 0.7 1.0 1.3 0.5 0.1 0.5 0.6 SUSC. SUSC. SUSC. SUSC. SUSC. SUSC. SUSC. 3.0 3.8 4.1 3.6 2.9 2.3 3.0 2.4 2.6 3.0 2.4 2.5 2.4 1.4 3.1 2.6 3.6 3.5 3.0 3.1 2.5 1.9 1.1 ADAPTATION TRIAL, CHIP-PROCESSING LINES MONTCALM RESEARCH FARM SEPTEMBER 24, 2002 (146 DAYS) LINE CWT/A US#1 TOTAL PERCENT OF TOTAL1 US#1 Bs As OV CHIP TUBER QUALITY2 PO SP GR SCORE3 HH VD IBS BC TOTAL NURSERY TRIAL CUT SCAB4 SCAB4 MAT5 BRUISE6 continued: SNOWDEN 265 W2033-8 263 MSH356-A 255 245 W1782-5 MSJ170-4 217 MEAN LSD0.05 249 56 311 319 278 270 270 290 54 85 82 92 91 81 15 16 7 9 18 83 82 85 88 80 2 1 7 3 1 0 1 1 0 1 1.072 1.071 1.070 1.072 1.077 1.072 0.003 1.0 1.0 2.0 1.0 2.0 1 0 10 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 40 40 40 40 40 2.0 1.3 1.0 1.5 2.0 1.3 0.5 0.3 1.4 0.9 2.6 1.9 2.5 2.1 2.6 SUSC. SUSC. LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials in 2002 at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3CHIP SCORE: Snack Food Association Scale (Out of the field, 9/25/02); Ratings: 1-5; 1: Excellent, 5: Poor. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: Taken August 21, 2002; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) 6BRUISE: These lines demonstrated blackspot bruise susceptibility in simulated bruise testing in 2002. Planted May 1, 2002 Table 8B LINE MAZAMA ATX85404-8W NDTX4930-5W NDTX4304-1R DURANGO RED CAL RED MSI077-4 CO89097-2RED MSI049-A MLBR MSJ317-1 LBR NDTX4271-5R NDC5281-2R ONAWAY MSJ319-7 LBR MSJ307-2 LBR SUPERIOR MSJ204-3 CHERRY RED MSI032-6 MEAN LSD0.05 ADAPTATION TRIAL, TABLESTOCK LINES MONTCALM RESEARCH FARM SEPTEMBER 18, 2002 (139 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A TUBER QUALITY2 US#1 TOTAL US#1 Bs As OV PO SP GR HH VD IBS BC PERCENT OF TOTAL1 TOTAL NURSERY TRIAL CUT SCAB3 SCAB3 MAT4 BRUISE5 442 409 401 396 387 380 372 362 359 332 326 320 313 309 301 275 272 257 239 339 43 480 443 429 430 422 439 389 399 397 357 355 371 353 347 344 292 291 327 279 376 49 92 92 94 92 92 86 96 91 90 93 92 86 88 89 87 94 93 79 86 8 6 4 6 8 13 3 7 6 7 8 11 6 11 7 4 5 17 13 85 83 83 89 86 86 69 81 69 89 87 84 81 82 79 90 81 78 85 7 9 10 3 6 1 27 9 21 4 5 2 8 7 8 5 12 1 0 0 2 2 1 1 0 1 3 4 0 0 3 6 0 6 2 2 4 1 0 10 3 0 2 0 1 0 2 1 0 0 0 0 0 1 0 4 0 28 0 4 3 3 0 8 12 2 6 1 1 3 3 2 9 1 1 1 1 0 0 0 0 3 0 0 2 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 2 3 0 0 0 0 0 0 0 0 0 0 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 1.063 1.072 1.067 1.044 1.063 1.062 1.069 1.063 1.060 1.070 1.057 1.060 1.058 1.067 1.056 1.060 1.059 1.064 1.071 1.062 0.004 1.3 1.7 3.3 2.7 - 1.3 2.3 3.0 2.5 2.5 2.0 3.3 1.7 3.0 2.3 0.3 2.0 2.0 2.7 0.9 1.1 1.3 0.8 0.5 0.5 2.4 1.0 1.7 1.8 0.9 1.4 0.1 1.9 1.3 0.0 0.4 0.9 0.9 2.4 3.0 1.6 1.1 3.4 3.0 3.6 1.9 2.9 4.6 1.1 1.5 1.4 2.6 3.5 1.0 3.1 1.0 2.8 LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials in 2002 at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 4MATURITY RATING: Taken August 21, 2002; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) 5BRUISE: These lines demonstrated blackspot bruise susceptibility in simulated bruise testing in 2002. No lines in this trial were bruise susceptible in 2002. Planted May 2, 2002 Table 9A MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS PRELIMINARY TRIAL, CHIP-PROCESSING LINES MONTCALM RESEARCH FARM SEPTEMBER 23, 2002 (139 DAYS) CWT/A PERCENT OF TOTAL1 LINE US#1 TOTAL US#1 Bs As OV CHIP TUBER QUALITY2 TOTAL NURSERY TRIAL PEDIGREE PO SP GR SCORE3 HH VD IBS BC SCAB4 SCAB4 MAT5 BRUISE6 FEMALE MALE MSJ316-A MSK498-1Y ATLANTIC MSK061-4 MSK188-AY MSK476-1 NY120 MSK469-1 MSH015-2 SNOWDEN R3-105 MSK409-1 MSG301-9 MSI061-B MEAN LSD0.05 485 421 314 306 304 280 271 263 256 254 237 228 207 186 287 124 501 452 345 354 311 329 322 309 285 302 253 265 242 214 320 121 97 93 91 86 98 85 84 85 90 84 94 86 85 87 3 7 7 13 2 14 16 15 7 16 5 13 14 11 81 91 80 84 78 85 84 83 87 82 80 84 84 83 16 2 11 3 20 0 0 2 3 2 14 2 1 4 0 0 2 1 0 0 0 0 3 0 1 1 1 2 1.073 1.071 1.074 1.076 1.068 1.082 1.064 1.074 1.076 1.072 1.085 1.074 1.064 - 1.073 1.5 2.0 1.0 1.5 1.5 1.5 2.0 1.5 1.5 1.0 1.0 1.5 1.5 1.5 4 0 12 0 1 0 0 1 2 1 7 1 1 0 0 0 1 3 0 0 1 0 0 2 0 0 2 0 1 8 1 0 0 0 0 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 CUT 20 20 20 20 20 20 20 20 20 20 20 20 20 20 1.0 1.3 2.7 2.0 2.0 1.0 1.0 2.7 1.0 2.0 3.7 2.0 1.0 1.5 0.5 0.8 2.0 0.8 1.5 1.0 1.5 1.8 0.8 2.0 2.0 1.5 0.3 1.8 4.0 2.8 3.0 3.3 3.5 3.5 2.3 3.5 1.8 2.0 2.8 2.5 2.0 1.8 Pike B0718-3 Saginaw Gold Brodick C148-A SUSC. NY101 H361-1 ND2676-10 H142-2 H228-6 H216-1 Atlantic H228-6 OP A091-1 C148-A Spartan Pearl S440 Brodick ND01496-1 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3CHIP SCORE: Snack Food Association Scale (Out of the field, 9/25/02); Ratings: 1-5; 1: Excellent, 5: Poor. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: Taken August 21, 2002; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) 6BRUISE: These lines demonstrated blackspot bruise susceptibility in simulated bruise testing in 2002. Planted May 7, 2002 Table 9B MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS PRELIMINARY TRIAL, TABLESTOCK LINES MONTCALM RESEARCH FARM SEPTEMBER 18, 2002 (134 DAYS) LINE US#1 TOTAL US#1 Bs As OV PO SP GR HH VD IBS BC CUT SCAB3 SCAB3 MAT4 BRUISE5 FEMALE PEDIGREE MALE CWT/A PERCENT OF TOTAL1 TUBER QUALITY2 TOTAL NURSERY TRIAL MSL766-1 LBR MSK106-B LBR MSK125-3 MSK217-3P SILVERTON RUS MSK214-1R MSL757-1 LBR MSK106-A LBR MSK117-A MSJ036-A MSK004-2Y MSG050-2 MSK247-9Y ONAWAY MSH308-2Y MSI092-3RY MSK004-AY MSK101-2 LBR MEAN LSD0.05 517 497 448 437 435 390 383 352 346 335 309 294 294 285 224 149 100 83 326 137 544 591 486 459 470 411 450 406 386 355 342 328 316 320 267 220 119 99 365 143 95 84 92 95 93 95 85 87 90 94 90 90 93 89 84 68 83 83 3 11 7 3 7 4 13 12 10 6 7 10 7 7 16 31 17 17 38 78 80 50 65 72 63 72 79 84 90 86 83 80 84 67 83 83 58 6 12 45 28 23 22 15 11 10 1 4 10 9 0 1 0 0 2 5 1 2 0 1 2 1 1 0 3 0 0 3 0 1 0 0 1.069 1.085 1.070 1.065 1.063 1.062 1.077 1.082 1.071 1.071 1.064 1.062 1.064 1.056 1.071 1.064 1.071 1.066 1.069 0.006 10 8 1 1 0 0 2 6 2 2 0 0 3 0 0 3 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 4 0 2 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 3.5 4.0 2.7 1.0 0.0 1.0 3.0 3.0 3.0 0.5 1.5 3.0 1.3 1.7 2.7 4.7 1.0 3.0 2.3 3.3 1.0 0.3 0.0 0.3 0.3 3.0 1.5 0.0 0.0 0.8 0.8 0.0 1.3 1.5 0.0 0.5 3.8 4.5 3.5 3.3 3.3 3.3 3.8 4.5 3.8 3.0 3.3 1.5 3.0 1.3 2.5 2.0 3.3 2.0 B0718-3 A91846-5R SUSC. F128-C G274-3 G214-1 G274-3 Russian Blue Picasso Picasso Prestile AWN86514-2 A84180-8 G274-3 F128-C OP H142-2 Zarevo A7961-1 Picasso SUSC. A097-1Y Eramosa L235-4 Yukon Gold Picasso F077-7 D040-4RY A097-1Y SUSC. F059-1 OP Chaleur Picasso G274-3 LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials in 2002 at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 4MATURITY RATING: Taken August 21, 2002; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) 5BRUISE: These lines demonstrated blackspot bruise susceptibility in simulated bruise testing in 2002. Planted May 7, 2002 Table 10 LINE FL1867 LIBERATOR ATLANTIC FL1879 SNOWDEN FL1833 MEAN MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS FRITO LAY CHIP-PROCESSING TRIAL MONTCALM RESEARCH FARM OCTOBER 7, 2002 (143 DAYS) CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV PO SP GR SCORE3 HH VD IBS BC CUT SCAB4 MAT5 BRUISE6 CHIP TUBER QUALITY2 TOTAL TRIAL 323 301 294 278 265 255 286 NS 354 347 317 288 285 263 309 59 91 87 93 97 93 97 8 7 5 3 7 2 87 79 70 75 84 57 4 8 23 21 9 41 1 6 3 1 0 1 1.071 1.078 1.079 1.066 1.073 1.074 1.074 0.004 1.0 1.0 1.0 1.5 1.5 1.5 3 0 23 10 7 19 0 2 2 3 14 1 0 1 0 0 0 1 0 0 0 0 1 0 40 40 40 40 40 40 2.4 0.4 2.1 2.5 2.4 0.6 1.5 3.1 2.6 2.1 2.8 3.0 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. 3CHIP SCORE: Snack Food Association Scale (Out of the field, 9/25/02); Ratings: 1-5; 1: Excellent, 5: Poor. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: Taken August 21, 2002; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) 6BRUISE: These lines demonstrated blackspot bruise susceptibility in simulated bruise testing in 2002. No lines in this trial were bruise susceptible in 2002. Planted May 17, 2002 2002 SCAB DISEASE TRIAL SCAB NURSERY, EAST LANSING, MI MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS Mean Rating* (0-5) Worst Rating (0-5) RESISTANT CATEGORY: Table 11 Potato Line A8893-1 AC89536-5Rus AC92009-4Rus MSE202-3Rus LIBERATOR MN18710Rus SILVERTON RUS W1836-3 A9014-2Rus MSE192-8Rus GOLDRUSH MSJ126-9 SUPERIOR MSG227-2 MSJ036-A KEYSTONE RUS CO85026-4 ND3196-1R TC1675-1Rus MSB106-7 DR NORLAND MSG301-9 MSH015-2 MSH356-A MSJ033-10Y MSJ316-A MSK004-AY MSK214-1R MSK217-3P MSK476-1 MN19525 NDC5372-1Rus NY120 RUSSET BURBANK SAGINAW GOLD PIKE RUSSET NORKOTAH Mean Rating (0-5) Worst Rating (0-5) Potato Line N MODERATELY RESISTANT CATEGORY: 3 3 6 3 3 3 3 3 6 3 4 2 2 2 2 4 2 3 3 3 7 CAL RED MSE149-5Y MSE221-1 MSH228-6 MSK247-9Y MSK498-1Y MAZAMA NY112 W1201 W2033-8 B0766-3 CO92077-2Rus MSE048-2Y MSG004-3 MSI061-B MSK004-2Y W1782-5 ATX85404-8W CO86218-2R MSE080-4 ONAWAY 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.7 1.7 1.7 1.7 2 2 3 2 2 2 2 2 3 2 2 2 2 2 2 2 2 2 2 2 3 N† 3 2 3 5 2 3 3 3 3 3 3 3 3 2 2 2 3 3 3 3 3 2 3 3 3 2 1 3 2 2 3 3 2 2 3 9 6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.3 0.3 0.3 0.5 0.5 0.5 0.7 0.7 0.7 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.1 1.2 0 0 0 0 0 0 0 0 1 0 1 1 1 1 1 1 2 1 2 2 2 1 2 2 1 1 1 1 2 2 1 2 1 1 1 2 3 *SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. †N = Number of plots evaluated. Table 11 continued 2002 SCAB DISEASE TRIAL SCAB NURSERY, EAST LANSING, MI MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS Mean Rating (0-5) Worst Rating (0-5) N† Mean Rating (0-5) Worst Rating (0-5) Worst Rating (0-5) SUSCEPTIBLE CATEGORY: Mean Rating (0-5) Potato Line SUSCEPTIBLE CATEGORY: SUSCEPTIBLE CATEGORY: Potato Line AF1775-2 B1240-1 CHERRY RED MSH095-4 MSH360-1 MSI005-20Y MSI152-A MSJ033-6Y MSJ080-8 MSJ147-1 MSJ167-1 MSJ170-4 MSJ204-3 MSJ319-1 MSJ456-4Y MSJ457-2 MSJ458-2 MSJ472-4P MSK061-4 MSK188-AY MSK409-1 ND5084-3R NDTX4271-5R NORVALLEY SNOWDEN V0498-9 W1980-4 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2 2 3 3 2 2 3 2 3 2 3 3 2 2 3 3 3 3 2 3 2 3 2 2 2 3 2 2 3 3 3 2 1 3 3 3 3 2 3 2 3 2 2 3 2 1 3 2 3 2 3 5 3 3 3.0 CO89097-2R 3.0 CV89023-2R 3.0 MSE030-4 3.0 MSG050-2 3.0 MSH067-3 3.0 MSJ319-7 3.0 MSK061-A 3.0 MSK101-2 3.0 MSK106-A 3.0 MSK117-A 3.0 MSK128-1 3.0 MSL757-1 ND2470-27 3.0 RED PONTIAC 3.0 MSI083-5 3.3 3.3 MSI582-A NDC5181-2R 3.3 NDTX4930-5W 3.3 3.5 A90586-11 A91790-13 3.5 3.5 MSL766-1 3.5 V0497-1 3.6 MSE018-1 AF1424-7 3.7 3.7 MSF099-3 3.7 MSI201-2PY 3.7 MSK049-2 3.7 MSR3-105 MSH017-C 4.0 4.0 MSI002-3 4.0 MSI077-5 MSK106-B 4.0 YUKON GOLD 4.0 4.3 TORRIDON MSI092-3RY 4.7 4 3 4 4 5 3 3 4 3 4 4 4 4 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 5 5 4 4 5 5 5 N 3 3 2 3 3 3 3 3 2 3 3 3 2 3 3 3 3 6 2 6 2 2 5 3 3 3 3 3 3 2 3 3 3 3 3 Potato Line MSF313-3 A90490-1 AC87340-2W BC0894-2W MSD040-4RY MSG147-3P MSH031-5 MSH041-1 MSH094-8 MSI077-4 MSJ307-2 MSK059-A W1386 W2062-1 MSF373-8 MSI049-A MSJ080-1 MSJ317-1 MSJ459-2Y MSK033-C MSK223-5 MSH063-2 MSH098-2 MSH308-2Y MSI032-6 MSJ197-1 MSJ308-BY MSJ453-4Y MSJ456-2 MSJ461-1 JACQUELINE LEE MSK031-A MSK034-1 MSK068-2 MSK123-5 MSK244-6 MSK469-1 MICHIGAN PURPLE ND5822C-7 NDTX4304-1R W1355 W1773-7 ATLANTIC W1431 N 4 3 3 3 3 3 3 3 3 3 3 3 3 3 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 11 6 3 4 3 3 4 3 3 3 3 3 3 3 4 3 3 3 3 3 3 3 3 4 3 3 3 3 3 3 3 3 3 3 3 3 3 4 4 3 4 3 3 3 4 4 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.8 *SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. †N = Number of plots evaluated. Table 12A VARIETY MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS 2002 BLACKSPOT BRUISE SUSCEPTIBILITY TEST SIMULATED BRUISE SAMPLES* NUMBER OF SPOTS PER TUBER 0 TOTAL 5+ TUBERS 1 2 3 4 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER ROUND WHITES: CHIP-PROCESSING LINES MSF099-3 MSG227-2 MSH094-8 PIKE LIBERATOR MSI083-5 MSJ461-1 SNOWDEN MSI002-3 MSE018-1 B0766-3 MSF373-8 W1201 ATLANTIC MSH095-4 5 7 6 4 8 10 10 4 10 8 12 5 5 10 5 20 18 18 19 15 13 13 16 12 13 10 13 10 6 6 1 2 2 2 2 4 3 2 2 5 5 4 4 ROUND WHITES: TABLESTOCK LINES MSE080-4 MSH031-5 ONAWAY MSF313-3 MSI152-A MSG004-3 MSE221-1 JACQUELINE LEE 22 23 22 19 19 18 8 9 3 1 2 6 6 6 9 7 1 1 7 8 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 1 2 1 3 1 2 1 1 5 4 5 1 1 1 80 72 72 76 60 52 52 64 48 52 40 52 40 24 24 88 92 88 76 76 72 32 36 0.200 0.280 0.320 0.320 0.480 0.560 0.560 0.600 0.640 0.720 0.760 0.920 1.200 1.360 2.000 0.120 0.160 0.160 0.240 0.240 0.320 1.040 1.040 * A-size tuber samples were collected at harvest, held at 50 F at least 12 hours, and placed in a six-sided plywood drum and rotated ten times to produce simulated bruising. Samples were abrasive-peeled and scored on October 24, 2002. The table is presented in ascending order of average number of spots per tuber. VARIETY NUMBER OF SPOTS PER TUBER 0 TOTAL 5+ TUBERS 2 1 3 4 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER LONG WHITES and RUSSETS 24 CO85026-4 24 MSE192-8RUS 23 RUSSET NORKOTAH MSE202-3RUS 22 22 KEYSTONE RUSSET 21 AC89536-5RUS 21 GOLDRUSH A8893-1RUS 20 20 RUSSET BURBANK 18 AC92009-4R 17 CO92077-2RUS TC1675-1RUS 13 6 NDC5372-1RUS 1 1 2 3 3 4 4 5 4 6 6 9 12 NORTH CENTRAL REGIONAL TRIAL V04981-1R RUSSET NORKOTAH D.R. NORLAND MSE202-2Rus MSF313-3 V0497-1 ND3196-1R ND5084-3R RUSSET BURBANK RED PONTIAC A9014-2Rus CV89023-2R MN19525R MSE221-1 ATLANTIC MN18710Rus MN15620LR MN18747Rus W1836-3Rus A90586-11Rus B0766-3 W1201 ND2470-27 SNOWDEN W1431 ND5822C-7 NORVALLEY NY112 W1386 MSE018-1 25 24 22 21 22 21 20 20 20 21 20 20 19 20 18 19 17 18 16 16 16 15 14 12 12 12 9 9 8 6 1 3 4 2 4 5 5 5 3 4 4 6 4 7 5 8 5 7 6 6 7 8 9 9 7 10 7 9 8 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 96 96 92 88 88 84 84 80 80 72 68 52 24 100 96 88 84 88 84 80 80 80 84 80 80 76 80 72 76 68 72 64 64 64 60 56 48 48 48 36 36 32 24 1 1 1 2 4 1 1 1 1 1 1 1 2 3 3 3 3 4 3 3 6 6 5 4 1 3 1 1 1 3 2 1 3 1 2 2 2 0.040 0.040 0.080 0.120 0.120 0.160 0.160 0.200 0.240 0.320 0.440 0.680 1.160 0.000 0.040 0.120 0.160 0.160 0.160 0.200 0.200 0.200 0.200 0.240 0.240 0.240 0.240 0.280 0.280 0.320 0.400 0.440 0.480 0.480 0.520 0.560 0.680 0.720 0.880 0.880 1.160 1.280 1.720 VARIETY NUMBER OF SPOTS PER TUBER 0 TOTAL 5+ TUBERS 2 4 3 1 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER 1 YELLOW FLESH and EUROPEAN TRIAL MSJ472-4P MSJ033-6Y YUKON GOLD MSI005-20Y MSJ033-10Y MSE149-5Y MSJ459-2Y SAGINAW GOLD MSJ453-4Y MSE048-2Y TORRIDON 24 24 23 21 18 15 15 13 12 5 7 2 2 6 9 6 8 6 15 8 1 1 1 3 3 5 4 6 2 1 1 1 1 2 1 1 1 1 1 1 1 ADAPTATION TRIAL, CHIP-PROCESSING LINES AC87340-2W A90490-1 MSH098-2 MSH228-6 MSJ170-4 W2033-8 BC0894-2W DAKOTA PEARL W1773-7 MSJ319-1 MSH067-3 MSJ080-1 MSJ080-8 MSJ197-1 ATLANTIC MSJ126-9 W1980-4 MSJ147-1 SNOWDEN W1782-5 MSH360-1 A97190-13 MSH112-6 MSH356-A MSJ456-2 B1240-1 MSJ167-1 MSJ456-4 W2062-1 25 24 23 23 22 22 21 22 22 20 19 19 18 17 16 18 15 13 14 13 12 12 16 13 12 10 8 8 7 1 1 1 3 3 4 2 2 5 6 5 6 7 8 4 9 8 7 8 9 7 2 6 7 7 6 7 7 1 1 1 1 2 1 4 2 3 3 5 3 4 2 4 8 6 7 2 1 1 1 3 4 2 3 2 1 1 1 1 2 2 2 1 1 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 96 96 92 84 72 60 60 52 48 20 28 100 96 92 92 88 88 84 88 88 80 76 76 72 68 64 72 60 52 56 52 48 48 64 52 48 40 32 32 28 0.040 0.080 0.080 0.320 0.320 0.440 0.600 0.680 0.920 1.040 1.400 0.000 0.040 0.120 0.120 0.120 0.120 0.160 0.160 0.160 0.200 0.240 0.280 0.320 0.360 0.400 0.440 0.440 0.640 0.680 0.680 0.720 0.800 0.840 0.920 0.920 1.160 1.240 1.320 1.480 VARIETY NUMBER OF SPOTS PER TUBER 0 TOTAL 5+ TUBERS 2 4 1 3 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER 1 1 1 1 1 1 ADAPTATION TRIAL, TABLESTOCK LINES CHERRY RED MSI049-A DURANGO RED MSI032-6 NDC5281-2R NDTX4271-5R ONAWAY SUPERIOR MAZAMA CO89097-2RED MSJ319-7 MSJ307-2 MSJ317-1 NDTX4304-1R CAL RED MSJ204-3 NDTX4930-5W ATX85404-8W MSI077-4 25 25 24 24 24 24 24 24 24 22 22 21 21 20 19 19 20 19 15 3 3 4 4 5 6 6 4 5 7 1 1 2 1 1 PRELIMINARY TRIAL, CHIP-PROCESSING LINES MSI061-B MSK061-4 MSG301-9 MSK409-1 MSK476-1 MSK498-1Y MSNY120 ATLANTIC MSR3-105 MSK469-1 SNOWDEN MSJ316-A MSK188-AY 25 22 21 20 19 21 19 16 16 17 14 11 11 3 4 5 5 3 5 8 8 6 8 12 9 1 1 1 2 2 3 1 1 2 1 1 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 1 100 100 96 96 96 96 96 96 96 88 88 84 84 80 76 76 80 76 60 100 88 84 80 76 84 76 64 64 68 56 44 44 0.000 0.000 0.040 0.040 0.040 0.040 0.040 0.040 0.080 0.120 0.120 0.160 0.160 0.200 0.240 0.240 0.240 0.280 0.560 0.000 0.120 0.160 0.200 0.320 0.320 0.320 0.400 0.400 0.440 0.600 0.640 0.840 VARIETY NUMBER OF SPOTS PER TUBER 0 TOTAL 5+ TUBERS 4 3 1 2 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER 1 PRELIMINARY TRIAL, TABLESTOCK LINES SILVERTON RUSSET MSI092-3RY ONAWAY MSK125-3 MSG050-2 MSJ036-A MSK004-AY MSK117-A MSK217-3P MSK106-A MSL757-1 MSH308-2Y MSL766-1 MSK247-9Y MSK101-2 MSK004-2Y MSK106-B 25 24 24 23 20 19 19 20 18 20 17 15 19 14 15 9 6 1 1 1 5 5 5 3 7 4 8 8 1 9 4 8 8 2 3 1 4 4 10 1 1 2 FRITO-LAY TRIAL LIBERATOR SNOWDEN FL1879 FL1867 FL1833 ATLANTIC 22 21 19 18 15 12 3 4 4 3 8 11 1 3 2 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 100 96 96 92 80 76 76 80 72 80 68 60 76 56 60 36 24 88 84 76 72 60 48 1 2 1 2 1 2 2 1 1 1 1 0.000 0.040 0.040 0.120 0.200 0.280 0.280 0.280 0.280 0.320 0.320 0.480 0.520 0.560 0.720 1.200 1.240 0.120 0.160 0.400 0.480 0.480 0.760 Table 13 MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS 2002 LATE BLIGHT VARIETY TRIAL MUCK SOILS RESEARCH FARM LINE RAUDPC1 MEAN N Table2 LINE RAUDPC1 MEAN N Foliar Resistance Category: MSJ456-2 3 3 MSJ461-1 3 JACQUELINE LEE LBR8 3 3 MSL766-1 3 LBR9 6 MSK106-A MSK101-2 2 3 MSJ457-2 6 MSK106-B 3 B0767-2 B0692-4 3 3 MSK128-A 3 MSJ453-4Y MSJ456-4 3 3 B0718-3 3 MSK128-1 3 MSJ458-2 AWN86514-2 3 3 TORRIDON 3 MSL757-1 6 MSJ307-2 MSJ319-7 3 3 MSL211-3 3 MSJ317-1 3 MSJ319-1 MSK027-C 3 3 A79543-4R 6 MSK049-A MSK136-2 3 3 MSK034-1 2 C085026-4 A90586-11 3 LSD0.05 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.1 0.2 0.3 0.4 0.4 0.7 0.8 0.9 1.1 1.1 2.5 2.7 2.8 2.8 2.9 4.0 4.0 4.6 5.1 5.9 6.1 6.2 6.3 7.0 Table 1,2 Table 3,4 Table 9B Table 9B Table 9B Table 9B Table 7 Table 8A Table 7 Table 9B Table 8B Table 8B Table 8B Table 8A Table 8B Table 6 Foliar Susceptibility Category (select lines) 3 : ZAREVO 7.3 8.1 BANNOCK RUSSET 8.4 ALTURAS RUSSET MSK125-3 9.2 9.3 GEM RUSSET 9.6 LBR5 10.6 MSI049-A IDA ROSE 10.8 12.6 LBR3 12.8 CAL WHITE 13.7 MSJ036-A LBR4 14.4 15.2 LBR2 16.3 KEYSTONE RUSSET RED PONTIAC 16.8 17.2 MSJ316-AY 17.4 YUKON GOLD 18.4 SNOWDEN DURANGO RED 18.9 19.3 MAZAMA 20.6 RUSSET BURBANK 22.5 RUSSET NORKOTAH ATLANTIC 22.8 23.8 DR NORLAND 24.2 PIKE 24.2 CAL RED SUPERIOR 25.0 25.1 IVORY CRISP 27.0 ONAWAY CHERRY RED 29.4 3 3 3 1 3 3 3 3 3 3 3 3 3 3 3 3 6 3 2 3 6 3 6 3 3 3 3 3 1 3 7.0 1 Ratings indicate the average plot RAUDPC (Relative Area Under the Disease Progress Curve). 2 Agronomic performance data of this line may be found on the referenced table. 3 160 potato varieties and advanced breeding lines were tested in all. For brevity purposes, only selected varieties and breeding lines are listed. Varieties and breeding lines with a mean RAUDPC value of 7.0 and less are considered resistant in 2002. Phytopthora infestans isolate 95-7 was inoculated 26 July 2002. Planted as a randomized complete block design consisting of 3 replications of 4 hill plots on 7 June 2002. TABLE 14 2002 FUSARIUM DRY ROT TRIAL Average Lesion Average Lesion Width (mm) Depth (mm) LINE W1836-3RUS MICHIGAN PURPLE RUSSET NORKOTAH W1386 MN15620LR MSK106-A MSK409-1 SILVERTON RUSSET BC0894-2W NY112 MSI077-4 CAL RED GOLDRUSH MSJ147-1 MSJ036-A CHERRY RED MSK217-3P MSG004-3 MSG301-9 NORVALLEY A8893-1RUS MSH067-3 CO92077-2RUS W2062-1 MSJ170-4 SUPERIOR DR NORLAND W1980-4 ND2470-27 ND3196-1R DURANGO RED MSJ080-1 W1773-7 MSE221-1 RED PONTIAC CV89023-2R MSI005-20Y SNOWDEN ONAWAY MSE202-3RUS W1201 MSJ126-9Y ATX85404-8W MSK061-4 W1782-5 MSK469-1 MSK214-1R MN18747RUS MSH015-2 AC92009-4R MSJ167-1 LSD0.05 Innoculated on 11/27/02. Readings taken on 12/16/02. 0.6 0.7 0.9 1.3 1.6 1.9 1.9 2.2 2.4 2.4 2.5 2.5 2.5 2.6 2.6 2.7 2.9 3.2 3.2 3.3 3.4 3.4 3.6 3.9 3.9 4.0 4.0 4.1 4.1 4.2 4.3 4.4 4.6 4.8 4.9 4.9 4.9 5.0 5.2 5.3 5.5 5.5 5.6 5.7 5.7 5.9 5.9 6.0 6.2 6.2 6.3 6.2 1.8 1.0 1.3 6.3 3.1 8.6 5.9 4.6 3.9 8.0 6.9 4.3 4.2 7.4 4.9 4.2 8.2 9.3 12.5 5.6 6.5 11.9 3.8 11.2 11.3 3.3 15.2 12.8 7.6 5.7 6.0 11.7 15.8 5.9 6.6 11.1 8.2 15.8 8.4 6.7 15.7 16.0 8.7 19.7 20.1 17.8 10.7 7.9 10.2 11.3 16.9 9.3 LINE V0498-1R ND5084-3R MSE192-8RUS B0766-3 MSJ080-8 MN18710 RUS NDTX4271-5R NDTX4304-1R RUSSET BURBANK FL1867 FL1833 MSG050-2 LIBERATOR MSH356-A MSH094-8 MSK498-1Y MSJ033-6Y CO85026-4 NY120 TC1675-1RUS W1201 V0497-1 MSJ204-3 MSJ197-1 FL1879 KEYSTONE RUSSET MSK476-1 A90490-1 W2033-8 CO89097-2R MSF099-3 MN19525R A9014-2RUS B1240-1 MSG227-2 ATLANTIC MSH112-6 AC89536-5RUS MSJ033-10Y A91790-13 MSH228-6 AC87340-2W MSK117-A MAZAMA MSH095-4 W1431 NDC5372-1RUS PIKE NDC5821-2R NDTX4930-5W MSI002-3 MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS Average Lesion Depth (mm) Average Lesion Width (mm) 6.4 6.4 6.4 6.4 6.5 6.5 6.6 6.7 6.7 6.9 6.9 7.1 7.1 7.2 7.3 7.3 7.5 7.6 7.7 7.7 7.8 7.8 8.1 8.4 8.4 8.6 8.7 8.9 9.0 9.3 9.3 9.5 9.6 9.6 10.0 10.5 10.6 10.6 10.8 10.9 11.0 11.9 12.6 12.7 12.8 13.7 13.8 14.4 15.0 15.9 15.9 6.2 10.5 8.5 9.3 20.7 18.4 9.0 15.8 15.4 16.0 15.1 16.7 17.3 19.9 22.9 24.2 18.9 18.9 8.7 17.3 11.7 13.9 13.5 24.7 19.3 15.2 16.9 21.1 18.5 8.8 17.4 18.7 18.4 12.1 19.7 18.7 20.5 21.5 10.0 22.6 18.3 16.4 30.2 17.6 22.1 21.2 16.3 16.0 23.8 22.9 16.5 21.0 9.3 Table 15 MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS 2002 POTATO SEED INVENTORY MSU Potato Breeding Program Introductions Availability of Michigan Certified Seed A Cumulative Inventory LINE LIBERATOR (MSA091-1) JACQUELINE LEE (MSG274-3) MICHIGAN PURPLE MSE192-8RUS MSE202-3RUS MSF099-3 MSG227-2 MSH031-5 MSH067-3 MSH095-4 MSI152-A MSJ319-1 MSJ461-1 MINI- TUBERS2 (UNITS) Y13 (CWT) Y23 (CWT) Y33 (CWT) 9638 6855 - - - 7520 868 6800 5377 2373 456 2390 7401 64 2.5 16 18 2 31 90 - - - - - 16 - 16 75 72 60 - - - - - - - - 80 - - - - 40 - - - - - - - Information listed above is a cumulative count from Golden Seed Farms, Iott Seed Farms Inc., Krueger Seed Farm, Marker Farms, and Sklarczyk Seed Farm. Table courtesy of Chris Long. Funding: Federal Grant, MPIC and SFA/USPB 2002 On-Farm Potato Variety Trials Chris Long, Dr. Dave Douches, Dr. Dick Chase, Don Smucker (Montcalm), Dave Glenn (Presque Isle), Jim Breinling (West Region) and Dr. Doo-Hong Min Introduction On-farm potato variety trials were conducted with 16 farms in 2002 at a total of 17 locations. Eight of the locations evaluated processing entries and nine evaluated fresh market entries. The processing cooperators were Crooks Farms Inc. (St. Joseph / Montcalm), L. Walther & Sons, Inc. (St. Joseph), Lennard Ag. Co. (Monroe), Fertile Valley Farms (Allegan), Main Farms (Montcalm) and Townview Farms (Montcalm). The SFA chip trial was at V & G Farms (Montcalm). Fresh market trial cooperators were Crawford Farms Inc. (Montcalm), DuRussel’s Potato Farms, Inc. (Washtenaw), Erke Farms (Presque Isle), Fedak Farms (Bay), Heiss Farms (Muskegon), Horkey Bros. (Monroe), Krummrey & Sons, Inc. (Ingham), M.J. Van Damme Farms (Marquette)and Newberry Correctional Facility (Luce). Procedure There were two types of processing trials conducted this year. The first type contained nine entries which were compared with check varieties Atlantic, Snowden and Pike. This trial type was conducted at Main Farms, Lennard Ag. Co., Fertile Valley Farms, and L. Walthers & Sons. Varieties in these trials were planted in 100’ strip plots. Seed spacing was grower dependent, but in general ranged from 9 to 13 inches. The Walther trial was planted in three replicated plots and harvested at two harvest dates of 98 and 119 days after planting. Plot size was 34” wide by 20 hills long. Seed spacing was 9”. The second type of processing trial, referred to as a “Select” trial, contained from seven to ten lines which were compared to the variety in the field. In these trials each variety was planted in a 15’ row plot. Seed spacing was 10 inches. Within the fresh market trials, there were 22 entries evaluated. There were 12 lines planted at each of the following locations; Bay, Marquette, Monroe, Montcalm, Presque Isle, and Washtenaw counties. The varieties in each trial ranged from mostly round white varieties to mostly russet varieties. These varieties were planted in 100’ strip plots. Again, spacing varied from 6 to 14 inches depending upon grower production and variety. Three fresh market “Select” trials were planted. They were located at Heiss Farms, Krummrey & Son, Inc. and Newberry Correctional Facility. These trials ranged from four to twelve varieties. Material from two trials was sent to processors for quality testing. Results A. Processing and “Select” Processing Variety Trial Results A description of the processing varieties, their pedigree and scab rating are listed in Table 1. The overall averages of the three locations of Allegan, Montcalm and Monroe Counties are shown in Table 2. The data from L. Walther & Sons in St. Joseph County is shown separately in Table 3 (first harvest, 98 days) and Table 4 (second harvest, 119 days). The overall averages of the “Select” processing trial, which is averaged across two growers, two counties and a total of three locations, are in Table 5. Processing Variety Highlights B0766-3, an introduction by Kathleen Haynes U.S.D.A. Beltsville, Maryland has shown some promise this year. It was the top overall yielder of the chip processing lines in 2002. This introduction has a nice, uniform shape and moderate scab tolerance. The size distribution is appealing with 95% of the production being marketable. B0766-3 appears to be an early bulking / early maturing variety, with estimated maturity later than Atlantic and slightly earlier than Pike. The Specific Gravity (SG) of this line may pose some concern here in Michigan, but in a normal year B0766-3 has had a SG of 1.085. Specific Gravity of this line ranged from 1.069 to 1.085 in Michigan. B0766-3 also exhibited the ability to store at 50 ºF into January, with potential to ship in March. Other lines that are showing some traits of interest are W1201, with the ability to bulk early and the potential for above average US#1 yield. MSG227-2 has scab tolerance and yield potential. Many off-types were noted this year in MSG227-2. Liberator has good out of the field chip quality and scab tolerance. MSH094-8 is proving to have excellent storage quality. B. SFA / USPB Chip Trial Results The Michigan location of the SFA / USPB chip trial was on the V & G Farm in Montcalm county. Table 6 shows the yields, size distribution and specific gravity of the entries when compared with Atlantic and Snowden. Table 7 shows the chip quality evaluations from samples processed and scored by Jays Foods, LLC, Chicago. C. Fresh Market and “Select” Fresh Market Variety Trial Results A description of the fresh pack varieties, their pedigree and scab rating are listed in table 8. Table 9 shows the overall average of six locations; Bay, Marquette, Monroe, Presque Isle and Washtenaw counties. Tables 10, 11 and 12 are “Select” trial locations from Heiss Farms (Muskegon Co.), Krummrey & Sons, Inc. (Ingham Co.) and Newberry Correctional Facility (Luce Co.), respectively. Fresh Market Variety Highlight Michigan Purple continues to show its adaptability to perform in many environments. This variety is near the top in almost all fresh market yield trials across the state. Averaging 427 cwt /A US#1 over a three year period with only one hollow-heart out of sixty oversize cut. It is susceptible to common scab, silver surf and other skin disorders. The flesh is a beautiful uniform white color. The purple skin is vibrant when harvested. Field selection is an important decision when raising a crop of Michigan Purple. It is important to avoid pathogens that would effect the appearance of this line. This variety has appealed to a wide ranging audience from Soup and Potato Salad processors to Table and Farm Market Producers. Keystone Russet, a Colorado russet introduction, which performed well this year in our russet trails and will be evaluated further. It does not seem to have a processing gravity, averaging only 1.064 across the state. The appearance and yield potential are acceptable, with a 355 US#1 yield and 77% of total yield being US#1 production. Other varieties of interest were Dakota Rose and MSF373-8. Dakota Rose was a moderate yielder at 322 US#1, with a nice red skin in most locations. MSF373-8 continues to perform well across locations, producing tubers that are low in internal defects with 97% US#1 production of which 42% were oversized. Overall US#1 yield for MSF373-8 was 347 cwt/A. Table 1. 2002 MSU Processing Potato Variety Trials Entry Characteristics Scab Rating* Pedigree 3.0 0.5 *Scab rating based on 0-5 scale; 0 = most resistant and 5 = most susceptible. Atlantic Liberator (MSA091-1) - MS702-80 X Norchip Pike Snowden B0766-3 - - B0243-18 X B9792- 157 (Coastal Chip) 1.5 3.0 1.0 MSF099-3 Snowden X Chaleur 3.0 MSF373-8 MS702-80 X NY88 MSG227-2 Prestile X MSC127-3 MSH094-8 MSE251-1 X W877 MSH095-4 MSE266-2 OP MSI002-3 MSI083-5 Liberator X MSF134-1 MSC135-5 X B0718-3 NY120 Kanona X AF186-2 W1201 Wischip X FyF 85 W1386 W876 X LD20-6 2.8 0.8 2.0 2.5 - 2.5 1.5 1.0 2.5 Early check variety. Mid season maturity, average yield, tubers round with some tendency to form Norchip off- types, chips best from 50 °F. Early/storage check variety. Late/storage check variety Early maturing, high yield, cold chip potential, resistant to golden nematode, some heat sprouts have been noted. Oval to oblong and slightly flattened, above average yield: low internal defects and excellent chip color from 42-46 °F. High yield, large tubers, low internal defects, medium deep eyes, out-of –field chipper. Average yield potential: flattened round shape, shallow eyes, low internal defects and excellent chip color from 48 °F. Mid season maturity, cold chipping potential 42 °F, low internal defects, Mid season maturity, bruise susceptibility equal to Snowden Round White chipper Late maturing, average yield, good chip color, low internal defects. Late Maturity, round, high yield potential, resistant to race Ro1 of golden nematode, dormancy like Atlantic. Late maturing, high yield, cold chipper 45 °F, deep eyes Late maturing, high yield, cold chipper 45 °F, like Snowden Table 2. 2002 Processing Potato Variety Trial Overall Average - Three Locations Allegan, Montcalm, Monroe Counties LINE B0766-3 MSF373-8 MSF099-3 MSH095-4 Atlantic W1201 Snowden MSG227-2 Liberator MSH094-8 Pike NY120 MEAN CWT/A US#1 356 350 340 316 308 305 301 258 242 239 216 193 285 TOTAL 377 362 388 357 363 354 377 341 293 285 288 296 340 1SIZE Bs: < 1 7/8" As: 1 7/8" - 3.25" OV: > 3.25" PO: Pickouts PERCENT OF TOTAL1 Bs OV 12 4 35 3 1 10 13 10 16 3 5 12 4 24 3 14 1 16 16 0 0 24 40 0 As 83 61 86 74 81 80 72 70 81 84 76 60 PO 1 1 3 3 0 3 0 13 2 0 0 0 US#1 95 96 87 87 84 85 76 73 82 84 76 60 82 CHIP SP GR SCORE3 1.069 1.073 1.073 1.070 1.072 1.082 1.072 1.066 1.068 1.065 1.072 1.055 1.070 1.0 1.2 1.0 1.0 1.0 1.0 1.0 1.2 1.0 1.2 1.0 1.2 TUBER QUALITY2 VD 1 0 1 2 1 0 2 0 3 0 2 0 IBS 0 0 0 0 1 0 0 0 0 0 0 0 HH 1 0 0 2 0 0 2 0 0 0 0 0 TOTAL CUT 30 30 30 30 30 30 30 30 30 30 30 30 COMMENTS Uniform Shape, Trace Scab Scab, Sheep Nose Pitted Scab, Long Type Trace Scab, Good Shape Scab Trace Surface Scab Pitted Scab Scab, Flat Type, Misshapen, Points Oblong, Points, Heat Necrosis Trace Scab, Oval Oblong Shape Trace Scab Small Size BC 0 0 0 0 0 0 0 0 0 0 0 0 3-YR AVG US#1 CWT/A 361* 446* 366 300* 355 - 340 298 - 255* 220* 252* 2TUBER QUALITY (number of tubers per total cut) HH: Hollow Heart VD: Vascular Discoloration IBS: Internal Brown Spot BC: Brown Center 3CHIP COLOR SCORE Snack Food Assoc. Scale (Out of the field) Ratings: 1 - 5 1: Excellent 5: Poor * Two-Year Average Table 3. 2002 Potato Processing Variety Trial L. Walther & Sons, Inc. (Three Rivers, MI) First Harvest1 August 7, 2001 ( 98 Days) PERCENT OF TOTAL2 CWT/A US#1 437 435 422 366 364 363 360 349 345 343 333 303 368 TOTAL 472 460 456 421 384 397 433 395 401 400 385 367 414 LINE Atlantic B0766-3 MSF099-3 MSG227-2 MSF373-8 W1201 NY120 Liberator Pike Snowden MSH094-8 MSH095-4 MEAN US#1 As 93 95 91 87 95 92 83 88 86 86 87 83 89 Bs 7 5 9 13 5 8 17 12 14 14 13 17 Small As 34 35 35 46 21 46 58 52 61 57 44 53 Large As 59 60 56 41 74 46 25 36 25 29 43 30 SP GR 1.075 1.071 1.076 1.074 1.070 1.082 1.065 1.074 1.075 1.072 1.075 1.076 1.074 HH3 4 1 0 1 2 1 0 0 1 0 0 1 Number of Internal Discolorations3 1 0 0 0 0 0 0 3 0 0 0 0 1All data presented is based on an average of three replications 2Percent of Total (Size) US#1: 1.8 - 4 in. Large As: 2.5 - 4 in. Small As: 1.8 - 2.5 in. Bs: < 1.8 in. Planted May 1, 2002 3Based on 30 tuber sample 9" seed spacing Vine Kill September 4, 2002 Table 4. 2002 Potato Processing Variety Trial L. Walther & Sons, Inc. (Three Rivers, MI) Second Harvest1 August 28, 2001 ( 119 Days) PERCENT OF TOTAL2 CWT/A US#1 497 471 467 456 435 434 418 398 388 385 347 346 420 TOTAL 530 513 508 484 464 447 480 465 431 439 431 409 467 LINE MSF099-3 Snowden Atlantic B0766-3 W1201 MSF373-8 MSH094-8 MSH095-4 Liberator MSG227-2 NY120 Pike MEAN US#1 As 93 92 92 94 94 98 87 85 90 88 81 85 90 Bs 7 8 8 6 6 2 13 15 10 12 19 15 Small As 30 55 38 36 36 13 36 47 47 40 66 53 Large As 63 37 54 58 58 85 51 38 43 48 15 32 SP GR - - - - - - - - - - - - Number of Internal Discolorations3 HH3 - - - - - - - - - - - - - - - - - - - - - - - - 1All data presented is based on an average of three replications 2Percent of Total (Size) US#1: 1.8 - 4 in. Large As: 2.5 - 4 in. Small As: 1.8 - 2.5 in. Bs: < 1.8 in. Planted May 1, 2002 3Based on 30 tuber sample 9" seed spacing Vine Kill September 4, 2002 Table 5. 2002 "Select" Potato Processing Variety Trial Overall Average - Two Growers, Two Counties Montcalm & St. Joseph Counties NUMBER OF LOCATIONS 3 2 2 3 3 3 3 LINE MSI002-3 W1201 MSH094-8 B0766-3 MSI083-5 Snowden NY120 MEAN CWT/A TOTAL US#1 489 451 376 345 342 339 272 373 536 551 408 359 383 375 361 425 PERCENT OF TOTAL1 OV Bs 5 7 5 18 2 7 16 3 5 8 6 9 24 1 As 87 64 90 80 85 85 74 US#1 92 82 92 96 90 91 75 88 PO 1 13 1 1 2 0 1 SP GR 1.074 1.081 1.080 1.076 1.071 1.076 1.064 1.075 HH 10 5 2 5 4 7 0 TUBER QUALITY2 VD 0 2 0 1 0 2 0 IBS 0 0 0 0 0 1 0 TOTAL CUT 25 15 15 25 25 25 25 BC 0 0 0 0 0 1 0 COMMENTS Trace Scab, Nice Type Sheep Nose Flat Blocky, Trace Pitted Scab Uniform Size Trace Scab, Nice Type Trace Scab 1SIZE Bs: < 1 7/8" As: 1 7/8" - 3.25" OV: > 3.25" PO: Pickouts 2TUBER QUALITY (number of tubers per total cut) HH: Hollow Heart BC: Brown Center VD: Vascular Discoloration IBS: Internal Brown Spot Table 6. CWT/A LINE AF1775-2 W1431 MSF099-3 Atlantic B0766-3 Snowden NY120 US#1 495 468 NDTX4930-5W 453 418 414 383 375 356 353 315 279 246 380 MSG227-2 AF1424-7 A91790-13 W1355-1 MEAN TOTAL 510 487 480 440 429 398 406 396 390 354 311 354 413 US#1 97 96 94 95 97 96 92 90 91 88 89 69 91 MICHIGAN STATE UNIVERSITY 2002 SFA / USPB Potato Variety Trial V & G Farms - Montcalm County October 18, 2002 Harvest / 148 Days PERCENT OF TOTAL1 OV Bs 1 21 17 4 19 3 11 5 13 2 4 8 7 8 2 9 13 4 12 0 19 7 31 0 As 76 79 75 84 84 88 85 88 78 88 70 69 PO 2 0 3 0 1 0 0 1 5 0 4 0 CHIP SP GR SCORE3 1.077 1.076 1.075 1.077 1.081 1.074 1.078 1.073 1.075 1.074 1.082 1.077 1.077 1.5 1.0 1.0 1.0 1.0 1.0 1.5 1.0 1.0 1.0 1.0 1.0 TUBER QUALITY2 VD 0 0 0 0 0 0 3 0 0 3 3 0 IBS 0 0 0 0 0 0 0 0 0 0 0 0 TOTAL CUT 30 30 30 30 30 30 30 30 30 30 30 30 SCAB4 0.7 0.7 3.2 1.3 0.5 0.0 0.3 0.2 0.2 2.8 1.8 0.5 BC 0 0 0 0 0 1 0 0 0 0 0 0 HH 7 21 1 0 8 1 0 0 4 0 2 0 3-YR AVG US#1 CWT/A 479* 385* 360* - 344 340 319 350 - - - - 1SIZE Bs: < 1 7/8" As: 1 7/8" - 3.25" OV: > 3.25" PO: Pickouts Planted: 23, 2002 Seed Spacing : 10.5" 2TUBER QUALITY (number of tubers per total cut) HH: Hollow Heart VD: Vascular Discoloration IBS: Internal Brown Spot BC: Brown Center 3CHIP COLOR SCORE Snack Food Assoc. Scale (Out of the field) Ratings: 1 - 5 1: Excellent 5: Poor 4SCAB DISEASE RATING 0: No Infection 1: Low Infection <5% 3: Intermediate 5: Highly Susceptible * Two-Year Average Table 7. MICHIGAN STATE UNIVERSITY 2002 SFA / USPB - V & G FARMS Post Harvest Chip Quality Evaluation* October 18, 2002 (148 DAYS AFTER PLANTING) NDTX4930-5W LINE AF1775-2 W1431 MSF099-3 Atlantic B0766-3 Snowden NY120 MSG227-2 AF1424-7 A91790-13 W1355-1 CHIP PERCENT CHIP DEFECTS SPECIFIC GRAVITY COLOR INTERNAL EXTERNAL TOTAL 23.0 14.0 11.7 30.9 21.8 21.0 10.7 15.4 9.5 9.2 9.8 10.3 1.077 1.076 1.075 1.077 1.081 1.074 1.078 1.073 1.075 1.074 1.082 1.077 61.1 60.9 60.0 60.0 61.3 61.8 61.4 62.1 62.8 61.5 62.3 62.2 19.8 12.3 8.6 26.5 19.3 16.3 7.6 8.8 8.2 8.0 7.8 8.8 3.2 1.8 3.1 4.4 2.6 4.7 3.1 6.6 1.3 1.2 2.0 1.5 *Samples processed and scored by Jays Foods, LLC., Chicago October 25, 2002 Table 8. Cal Red Cherry Red (DT-6063-1R) - - Dakota Pearl (ND2676-10) Dakota Rose (ND3574-5R) ND1118-1 X ND944-6 ND1196-2R X NorDonna Durango Red (CO86218-2) Sangre X NDTX9-1068-11R Goldrush - 0.7 - - - Jacqueline Lee (MSG274-3) Tollocan X Chaleur 3.5 Keystone Russet (AC83064-1) CalWhite X A7875-5 Mazama (NDO2686-6R) ND1196-2R X Redsen - - Michigan Purple W870 X Maris Piper 3.0 Onaway - 1.2 2002 MSU Freshpack Potato Variety Trials Characteristics Scab Rating* Pedigree Entry - - - Moderate response to blackspot and shatter bruise, skin set 21 days after vine kill, stores well, moderately resistant to fusarium day rot. Early maturing, low internal defects, average yield, cold chipping potential at 42 °F. High yield, nice appearance, resistant to silver scurf, maintains color in storage, good size tubers, short dormancy, skinning Medium maturity, high yield, holds red skin in storage, sticky stolons may result in high nitrogen use areas. Long to oval tubers, heavy russet, check variety Oval shape, light yellow flesh, low internal defects, heavy tuber set (15-18/hill), strong foliar resistance to US8 late blight. Medium maturity, high yield, resistant to scab, good storability, good internals, resistant to blackspot, short dormancy Low defects, high yield of small size tubers, skin color holds in storage Mid season, attractive purple skin, white flesh, high yield potential, low incidence of internal defects Early maturing check variety. Entry Reba (NY 87) Pedigree Monona X Allegany Scab Rating* 2.5 Russet Burbank Russet Norkotah - - Silverton Russet (A083064-6) Superior MSB106-7 MSE192-8 Rus MSE202-3 Rus MSF373-8 MSG004-3 MSH031-5 CalWhite X A7875-5 - LaBelle X Lemhi Russet A81163 X Russet Norkotah Frontier Russet X A8469-5 MS702-80 X NY88 Mainestay X MS702-80 MSB110-3 X MSC108-3 Characteristics High yield, bright tubers, low incidence of internal defects, mid to late season. Long tubers, russet check variety Long to oval tubers, heavy russet, check variety Oblong to long, medium russet skin, medium to high yield. Average yielding check variety Long white skin tubers, high yield and low internal defects. Long russet tubers, low internal defects, bright white flesh, good cooking quality, SG similar to Long russet, lighter russet like R. Norkotah. R. Burbank. High yield, large tubers, low internal defects, medium deep eyes. Average yield, bright skin, low internal defects. Medium maturity, medium yield, low SG, nice appearance, tolerant to black spot 1.0 2.5 - 1.5 1.6 1.2 0.5 2.8 3.0 2.7 *Scab rating based on a 0-5 rating; 0 = most resistant and 5 = most susceptible. Table 9. NUMBER OF LOCATIONS 6 4 4 4 4 2 6 4 3 2 4 2 4 4 3 4 2 4 3 LINE Michigan Purple MSH031-5 Keystone R. Onaway MSF373-8 MSG004-3 Dakota Rose Durango Red Dakota Pearl Reba Silverton R. Superior Jacqueline Lee R. Norkotah Mazama MSE202-3Rus Cal. Red MSE192-8Rus Goldrush MEAN 2002 Potato Variety Freshpack Trial Overall Averages - Six Locations Bay, Marquette, Monroe, Montcalm, Presque Isle, Washtenaw Counties 3-YR AVG CWT/A TOTAL US#1 408 373 355 348 347 331 322 316 308 300 292 277 272 264 260 235 228 205 162 295 460 424 451 382 356 359 349 388 331 322 351 300 431 360 313 317 335 264 224 353 PERCENT OF TOTAL1 OV Bs 20 6 3 11 15 10 13 6 42 3 19 7 11 8 17 6 5 6 14 7 19 15 10 7 33 0 9 28 9 16 7 16 0 31 19 13 4 23 As 69 85 67 78 55 73 80 75 88 79 64 82 63 59 73 68 68 64 68 US#1 89 88 77 91 97 92 91 81 93 93 83 92 63 68 82 75 68 77 72 83 PO 5 1 8 3 0 1 1 2 1 0 2 1 4 4 2 9 1 4 5 SP GR 1.067 1.074 1.064 1.064 1.073 1.063 1.057 1.064 1.073 1.064 1.069 1.060 1.077 1.066 1.068 1.074 1.061 1.068 1.064 1.067 HH 1 0 0 0 0 1 3 0 0 0 3 0 0 1 0 4 0 0 0 TUBER QUALITY2 VD 0 1 14 4 0 0 5 4 0 0 0 0 1 2 8 2 0 7 0 IBS 0 0 0 2 0 0 1 2 0 0 0 0 0 0 1 1 0 0 0 TOTAL CUT 60 40 40 40 40 20 60 40 30 20 40 20 40 40 30 40 20 40 30 COMMENTS Pitted Scab, Off types in Oversize Trace Pitted Scab, Bright Appearance Oblong to Long Sheep Nose, Deep Eyes Slight Surface Scab Slight Surface Scab Growth Crack Sticky Stolons, Netting on Skin Uniform Size Good Appearance Blacksurf Trace Scab, Small Size Trace Scab Light Red Skin Trace Scab, Knobs Sticky Stolons, Netting on Skin Stem End Points, Trace Pitted Scab Nice Russet Color, Small Size BC 0 0 0 0 0 0 0 0 5 1 3 0 0 0 0 0 0 0 0 US#1 CWT/A 427* - - 421 492 310* - - - - - - - 284* 326 230* 184* 208* 190* 1SIZE Bs: < 1 7/8" or < 4 oz. As: 1 7/8" - 3.25" or 4 - 10 oz. OV: > 3.25" or > 10 oz. PO: Pickouts 2TUBER QUALITY (number of tubers per total cut) HH: Hollow Heart BC: Brown Center VD: Vascular Discoloration IBS: Internal Brown Spot * Two-Year Average Table 10. 2002 "Select" Potato Variety Freshpack Trial Heiss Farms - Muskegon County October 17, 2002 Harvest / 147 Days LINE Michigan Purple MSF373-8 Dk. Red Norland Jacqueline Lee MEAN US#1 630 470 375 293 442 CWT/A TOTAL 665 471 422 411 492 PERCENT OF TOTAL1 OV Bs 2 21 30 0 6 7 24 0 As 74 70 82 71 US#1 95 100 88 71 89 PO 3 0 5 5 SP GR 1.069 1.077 1.054 1.077 1.069 HH 0 0 0 0 TUBER QUALITY2 VD 1 0 0 0 IBS 0 0 0 0 TOTAL CUT 5 5 5 5 BC 0 0 0 0 COMMENTS Sheep Nose 1SIZE Bs: < 1 7/8" or < 4 oz. As: 1 7/8" - 3.25" or 4 - 10 oz. OV: > 3.25" or > 10 oz. PO: Pickouts 2TUBER QUALITY (number of tubers per total cut) HH: Hollow Heart VD: Vascular Discoloration IBS: Internal Brown Spot BC: Brown Center Planted: May 24, 2002 Seed Spacing: Jacqueline was planted at a 14" spacing. All other varieties were planted at 9". Table 11. 2002 "Select" Potato Variety Freshpack Trial Krummrey & Sons, Inc. - Ingham County September 21, 2002 Harvest / 123 Days LINE MSF373-8 Michigan Purple Dakota Pearl MSH031-5 Cal Red Dakota Rose Red Norland MEAN CWT/A TOTAL US#1 223 181 167 152 125 119 86 150 245 225 233 201 189 170 132 199 PERCENT OF TOTAL1 OV Bs 43 3 14 13 0 26 0 16 0 34 0 19 31 7 As 48 68 71 75 66 70 59 US#1 91 81 71 75 66 70 66 74 PO 6 5 3 9 0 11 3 SP GR 1.068 1.065 1.062 1.063 1.059 1.054 1.055 1.061 HH 0 0 0 0 0 0 0 TUBER QUALITY2 VD 0 0 4 0 2 0 0 IBS 0 0 0 0 0 0 0 TOTAL CUT 10 10 10 10 10 10 10 BC 0 0 0 0 0 0 0 COMMENTS Trace Pitted Scab, Skinning Growth Crack, Misshapen Misshapen Trace Surface Scab, Misshapen Growth Crack, Sticky Stolon, Netted Skin Misshapen Growth Crack 1SIZE Bs: < 1 7/8" or < 4 oz. As: 1 7/8" - 3.25" or 4 - 10 oz. OV: > 3.25" or > 10 oz. PO: Pickouts 2TUBER QUALITY (number of tubers per total cut) HH: Hollow Heart VD: Vascular Discoloration IBS: Internal Brown Spot BC: Brown Center Planted: May 24, 2002 Vines Killed: September 4, 2002 (104 Days) Seed Spacing: 6" Table 12. 2002 "Select" Potato Variety Freshpack Trial Newberry Correctional Facility - Luce County October 23, 2002 Harvest / 149 Days CWT/A TOTAL Dakota Rose LINE Reba US#1 316 237 221 221 202 189 139 126 126 120 114 95 69 54 51 32 144 330 256 253 253 221 248 183 170 142 170 230 328 177 155 168 95 211 MSH031-5 Dakota Pearl MSF373-8 R. Norkotah Michigan Purple MSB106-7 Superior MSE192-8Rus Silverton R. Jacqueline Lee Goldrush R. Burbank Keystone R. MSE202-3Rus MEAN PERCENT OF TOTAL1 OV Bs 8 4 2 7 13 0 0 10 6 9 13 23 17 3 0 15 13 9 0 30 51 0 0 65 4 57 0 57 70 0 0 67 As 88 91 87 87 85 63 73 74 76 70 49 29 35 35 30 33 US#1 96 93 87 87 91 76 76 74 89 70 49 29 39 35 30 33 66 PO 0 0 0 3 0 1 7 11 2 0 0 6 4 8 0 0 SP GR 1.069 1.078 1.083 1.082 1.084 1.074 1.085 1.080 1.081 1.073 1.075 1.083 1.079 1.084 1.071 1.082 1.079 HH 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 TUBER QUALITY2 VD 1 0 0 1 0 0 0 0 1 0 0 0 0 0 6 0 IBS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 COMMENTS Nice Skin, Good Color Deep Eyes Small Size Small Size TOTAL CUT 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 BC 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1SIZE Bs: < 1 7/8" or < 4 oz. As: 1 7/8" - 3.25" or 4 - 10 oz. OV: > 3.25" or > 10 oz. PO: Pickouts 2TUBER QUALITY (number of tubers per total cut) HH: Hollow Heart VD: Vascular Discoloration IBS: Internal Brown Spot BC: Brown Center Planted: May 28, 2002 Vines Killed: September 6, 2002 (102 Days) Seed Spacing: 11.5" Nitrogen Level: 228 lb/A POTATO (Solanum tuberosum L.‘Pike’) Black scurf and stem canker; Rhizoctonia solani Funding Industry W. W. Kirk, R. L Schafer and D. Berry Department of Plant Pathology Michigan State University East Lansing, MI 48824 Seed treatments, in-furrow and seed plus foliar treatments for control of potato stem canker and black scurf, 2002. Potatoes infected with Rhizoctonia solani (black scurf), 2- 5% tuber surface area infected, were selected for the trials. Potato seed was prepared for planting by cutting and treating with fungicidal seed treatments seven days prior to planting.. Seed were planted at the Michigan State University M uck Soils Experimental Station, Bath, MI on 29 Jun into two-row by 20-ft plots (ca. 10-in between plants to give a target population of 50 plants at 34-in row spacing) replicated four times in a randomized complete block design. The two-row beds were separated by a five-foot unplanted row. Dust formulations were measured and added to cut seed pieces in a Gustafson revolving drum seed treater and mixed for two minutes to ensure even spread of the fungicide. Fungicides applied as pre-planting potato seed liquid treatments were applied in water suspension at a rate of 0.02pt/cwt onto the exposed seed tuber surfaces, with the entire seed surface being coated in the Gustafson seed treater. In furrow applications were made over the seed at planting, applied with a single nozzle R&D spray boom delivering 5 gal/A (80 p.s.i.) and using one XR11003VS nozzle per row. Fertilizer was drilled into plots before planting, formulated according to results of soil tests. Additional nitrogen (final N 28 lb/A) was applied to the growing crop with irrigation 45 DAP (days after planting). Bravo WS 6SC was applied at 1.5 pt/A on a seven day interval, total of 8 applications, starting after the canopy was about 50% closed. A permanent irrigation system was established prior to the commencement of fungicide sprays and the fields were maintained at soil moisture capacity throughout the season by frequent (minimum 5 day) irrigations. Weeds were controlled by hilling and with Dual 8E at 2 pt/A 10 DAP, Basagran at 2 pt/A 20 and 40 DAP and Poast at 1.5 pt/A 58 DAP. Insects were controlled with Admire 2F at 1.25 pt/A at planting, Sevin 80S at 1.25 lb/A 31 and 55 DAP, Thiodan 3 EC at 2.33 pt/A 65 and 87 DAP and Pounce 3.2EC at 8 oz/A 48 DAP. Emergence was rated as the number of plants breaking the soil surface or fully emerged after planting. The rate of emergence was estimated as the area under the plant emergence curve (max=100) from the day of planting until 29 days after planting. The rate of canopy development was measured as the RAUCPC, relative area under the canopy development curve, calculated from day of planting to a key reference point taken as 49 DAP (about 100% canopy closure), (max = 100). Severity of stem canker was estimated as the percentage of stems per plant with greater than 5% girdling caused by R. solani, measured 70 days after planting (5 plants per sample were destructively harvested and total stem number and number affected was counted). Vines were killed with Reglone 2EC (1 pt/A on 20 Sep). Plots (25-ft row) were harvested on 29 Oct and individual treatments were weighed and graded. Samples of 50 tubers per plot were harvested 14 days after dessication (approximately 135 DAP). Tubers were washed and assessed for black scurf (R. solani) incidence (%) and severity 40 days after harvest. Severity of black scurf was measured as an index calculated by counting the number of tubers (n = 50) falling in class 0 = 0% ; 1 = 1 - 5%; 2 = 6 -10%; 3 = 11 - 15; 4 >16%surface area of tuber covered with sclerotia. The number in each class is multiplied by the class number and summed. The sum is multiplied by a constant to express as a percentage. Indices of 0 - 25 represent 0 - 5%; 26 - 50 represent 6 - 10%; 51 - 75 represent 11 - 15% and 75 - 100 >15%surface area covered with sclerotia. No seed treatment (ST) or fungicide applied at planting in-furrow (IF) was significantly different from the untreated control or from the Maxim MZ 0.5 lb (ST) commercial standard treatment in terms of the final plant stand (91 - 100%). Maxim MZ 0.75 lb (ST) emerged at a significantly lower rate [relative rate of emergence (RAUEPC)] than the untreated control. No other treatments emerged at a rate significantly different from the untreated control or from the Maxim MZ 0.5 lb (ST) commercial standard treatment. Messenger 1.4 oz/1000 ft (IF) had a significantly lower rate of canopy formation (RAUCPC) than the untreated control but no other treatments were significantly different form the untreated control or from the Maxim MZ 0.5 lb (ST) commercial standard. Seed treatments and in-furrow applications of fungicides were not phytotoxic. All treatments significantly reduced the percentage of stolons with greater than 5% girdling due to R. solani in comparison with the untreated control. Headsup 0.002 lb (ST) had significantly more stolon girdling (29.2%) in comparison to the commercial standard. No treatments significantly reduced the percent incidence of black scurf on tubers in comparison with the untreated control or the commercial seed treatment standard. All treatments significantly reduced incidence of black scurf on tubers in comparison with the untreated control. There was no significant difference in incidence of black scurf between treatments with 7.5% [Moncoat MZ 0.75 lb (ST)] to 16.3% [Maxim MZ 0.75 lb ST)] and included the commercial standard [Maxim MZ 0.5 lb (ST), 11.3%]. Messenger 1.4 oz/1000 ft (IF) and Headsup 0.002 lb (ST) had significantly greater incidence (%) of black scurf on tubers than the commercial standard. All treatments significantly reduced the severity of tuber black scurf in comparison with the untreated control. There was no significant difference in the index of severity of black scurf between treatments with indices between 1.9 [Moncoat MZ 0.75 lb (ST)] to 4.7 the commercial standard [Maxim MZ 0.5 lb (ST), 4.7]. Messenger 1.4 oz/1000 ft (IF) and Headsup 0.002 lb (ST) had significantly more severe tuber black scurf then the commercial standard but all other treatments were not significantly different in terms of severity of tuber black scurf from the commercial standard. No treatments were significantly different from the untreated control or the commercial seed treatment standard in terms of marketable or total yield. Treatment and rate/cwt (seed treatment) rate/A (in furrow) 1 Tops MZ 0.75 lb 2 Quadris 2.08SC 0.05 fl.oz/1000 ft 3 Moncoat MZ 0.75 lb 4 Moncut 70DF 0.79 oz/1000 ft 5 Moncut 70DF 1.18 oz/1000 ft 6 6% Mancozeb 1lb 7 Maxim MZ 0.5 lb 8 Maxim MZ 0.75 lb 9 Messenger 1.4 oz/1000 ft 10 Headsup 0.002 lb 11 Untreated Application timingz Plant number (%) emerged 29 days after planting Emergence (RAUEPC)y ST......... IF.......... ST......... IF.......... IF.......... ST......... ST......... ST......... IF.......... ST......... NA........ 99.5 97.0 100.0 96.0 95.0 100.0 94.5 91.0 92.5 99.0 99.5 aw a a a a a a a a a a 0.26 0.27 0.28 0.25 0.25 0.28 0.25 0.24 0.25 0.26 0.27 ab ab ab bc bc ab bc c bc ab ab Funding Industry Canopy development (RAUCPC)x 0.56 0.53 0.55 0.56 0.50 0.55 0.53 0.48 0.46 0.53 0.53 ab ab ab ab cd ab ab cd d abc abc Yield cwt/A Totalr a a a a a a a a a a a Application timingz Percent stolons with greater than 5% girdling due Incidence of black scurf on tubers (%)u Index of severity of black scurf on tubers (%)t Marketable (US1)s 357 347 349 356 346 336 351 358 345 354 ST......... IF.......... ST......... IF.......... IF.......... ST......... ST......... ST......... IF.......... 12.5 de 10.0 de 7.5 e 12.5 de 13.8 de 21.3 d 11.3 de 16.3 de 50.0 bc ef 3.4 ef 3.1 f 1.9 ef 3.4 ef 4.1 e 6.9 ef 4.7 4.7 ef 18.4 b 14.1 cd 22.8 a to R. solaniv 21.6 cdefgw 18.7 defg 15.6 fg 24.9 bcd 14.8 g 28.4 bc 22.5 cdef 18.3 defg 22.7 bcde Treatment and rate/cwt (seed treatment) rate/A (in furrow) 1 Tops MZ 0.75 lb 2 Quadris 2.08SC 0.05 fl.oz/1000 ft 3 Moncoat MZ 0.75 lb 4 Moncut 70DF 0.79 oz/1000 ft 5 Moncut 70DF 1.18 oz/1000 ft 6 6% Mancozeb 1lb 7 Maxim MZ 0.5 lb 8 Maxim MZ 0.75 lb 9 Messenger 1.4 oz/1000 ft 10 Headsup 0.002 lb 11 Untreated z Application type, seed treatment (ST), in-furrow at planting (IF), untreated (NA). y RAUEPC (max = 100), relative area under the plant emergence progress curve calculated from the day of planting to full emergence at 29 days after planting. x RAUCPC (max = 100), relative area under the canopy development curve calculated from day of planting to key reference point, 50 days after planting (about 100% canopy closure). w Values followed by the same letter are not significantly different at P = 0.05 (Tukey M ultiple Comparison). v Percentage of stems with greater than 5% girdling caused by R. solani, average of 5 plants taken 70 days after planting. u Percent incidence of tubers with sclerotia of R. solani from sample of 50 tubers per replicate. t Severity of black scurf (index calculated by counting tuber number (n = 50) falling in class 0 = 0%; 1 = 1 - 5%; 2 = 6 -10%; 3 = 11 - 15%; 4 >16%surface area. Indices of 0 - 25 cover the range 0 - 5%; 26 - 50 cover the range 6 - 10%; 51 - 75 cover the range 11 - 15% and 75 - 100 >15% surface area of tuber with sclerotia. s Marketable yield, tubers greater than 2.5" in any plane (US1 grade). r Total yield, combined total of US1 grade and tubers less than 2.5" in any plane. 387 372 374 384 377 364 384 385 368 382 366 ST......... NA........ 29.2 b 40.5 a 41.3 c 70.0 a a a a a a a a a a a a 336 POTATO (Solanum tuberosum L.‘Pike’ and ‘FL1879') Fusarium dry rot; Fusarium sambucinum Funding MPIC W. W. Kirk, R. L Schafer and D. Berry Department of Plant Pathology Michigan State University East Lansing, MI 48824 Timing of application of seed treatments, for control of fusarium dry rot in potatoes, 2002. Potato seed cvs. Pike and FL1879 was prepared for planting by cutting and inoculating with Fusarium sambucinum (dry rot) and treating with fungicidal seed treatments 2, 5 and 10days before planting (DBP). A treatment with no inoculation was included at each of the cutting dates. Potatoes free from dry rot were selected for the trials. Cut seed was inoculated with an aggressive isolate of F. sambucinum which was grown on potato-dextrose agar for 14 days. Conidia were harvested from the plates and concentration, determined by hemacytometer was adjusted to 3.4 x 103 conidia/fl.oz.. The seed pieces (160/treatment) were sprayed with 4 fl.oz. of the pathogen suspension, for a final dosage of about 0.03 fl.oz applied per tuber. Dust formulations of seed treatments were measured and added to cut seed pieces in a Gustafson revolving drum seed treater and mixed for two minutes to ensure even spread of the fungicide. In a second trial, potato seed cv. Pike was prepared for planting by cutting and inoculating with Fusarium sambucinum (dry rot) and treating with fungicidal seed treatments 2DBP. Fungicides applied as pre-planting potato seed liquid treatments were applied in water suspension at a rate of 0.02pt/cwt onto the exposed seed tuber surfaces, with the entire seed surface being coated in the seed treater. Foliar applications were applied with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Seed was planted at the Michigan State University Montcalm Potato Research Farm, Edmore, MI on 15 May into single-row by 30-ft plots (ca. 9-in. between plants to give a target population of 40 plants at 34-in. row spacing) replicated four times in a randomized complete block design. Fertilizer was drilled into plots before planting, formulated according to results of soil tests. Additional nitrogen (final N 28 lb/A) was applied to the growing crop with irrigation 45 DAP (days after planting). Bravo WS 6SC was applied at 1.5 pt/A on a seven-day interval (eight applications), starting after the canopy was about 50% closed. A permanent irrigation system was established prior to the commencement of fungicide sprays and the fields were maintained at soil moisture capacity throughout the season by frequent (minimum 5 day) irrigations. Weeds were controlled by hilling and with Dual 8E at 2 pt/A 10 DAP, Basagran at 2 pt/A 20 and 40 DAP and Poast at 1.5 pt/A 58 DAP. Insects were controlled with Admire 2F at 1.25 pt/A at planting, Sevin 80S at 1.25 lb/A 31 and 55 DAP, Thiodan 3 EC at 2.33 pt/A 65 and 87 DAP and Pounce 3.2EC at 8 fl. oz/A 48 DAP. For both trials, samples from each treatment (n = 25) were incubated at 50oF (95% RH) in controlled environment chambers for 14 days and the total number of healthy and dry rot affected sprouts was calculated in addition to the development of dry rot on the seed piece measured as percent decay. Three way analysis of variance was run for all combinations of treatments common to the two varieties, i.e. variety, presence of seed treatment, timing of treatment and presence of inoculum. Treatments were compared using two way ANOVA. Emergence was rated as the cumulative number of plants breaking the soil surface or fully emerged after planting. The rate of emergence was estimated as the area under the plant emergence curve (max=100) from the day of planting until 22 days after planting. The rate of canopy development was measured as the RAUCDC, relative area under the canopy development curve, calculated from day of planting to a key reference point taken as 58 DAP (about 100% canopy closure), (max = 100). Vines were killed with Reglone 2EC (1 pt/A on 5 Sep). Plots (40-ft row) were harvested on 9 Oct and individual treatments were weighed and graded. A three-way ANOVA showed that the effect of timing of cutting, presence of seed treatment and variety all significantly affected sprout development, percent incidence of diseased sprouts and seed-piece decay as well as stand and canopy development, however there was no effect on final marketable yield. The timing of seed cutting and application of the seed treatment Maxim MZ significantly affected the total number of developing sprouts in both varieties (Table 1). In cv. FL1879 preparing seed 5 days before planting (DBP) resulted in significantly fewer sprouts in the absence of a Maxim MZ seed treatment but was not significantly different from the corresponding non-inoculated control. Cutting and treating 2 DBP had overall less effect on sprout development in FL1879. In Pike, only the non-inoculated control prepared 2 DBP planting had significantly fewer sprouts than any of the other treatments between which was no significant difference. The effect of timing of cutting, presence of seed treatment and variety significantly affected the percentage of sprouts with symptoms of dry rot caused by F. Sambucinum (dark lesions with loss of sprout viability). Non-inoculated seed had no sprouts infected and Maxim MZ had significantly fewer diseased sprouts at 2 and 5DBP planting treatments than non-treated inoculated comparisons but at 10 DBP there was no significant effect of the seed treatment in FL1879. In Pike, non-inoculated seed had no sprouts infected and Maxim MZ had significantly fewer diseased sprouts at 2, 5 and 10 DBP planting treatments than non- treated inoculated comparisons. Non-inoculated seed had no seed-piece decay and Maxim MZ had significantly less seed- piece decay at 10 DBP planting treatments than non-treated inoculated comparisons but at 2 and 5 DBP there was no significant effect of the seed treatment in FL1879. In Pike, non-inoculated seed had no seed-piece decay and Maxim MZ had significantly less seed piece decay at 2, 5 and 10 DBP planting treatments than non-treated inoculated comparisons. Final plant stand was significantly lower in non-treated inoculated comparisons 10 DBP but no other treatments differed significantly in terms of plant stand in FL1879. In Pike, final plant stand was significantly lower in non-treated inoculated comparisons 5 and 10 DBP but no other treatments differed significantly in terms of plant stand. Rate of emergence Funding MPIC (RAUEPC) in FL1879 was significantly lower in non-treated inoculated comparisons at 10 DBP but no other treatments differed significantly in terms of RAU EPC. In Pike, RAUEPC was significantly lower in non-treated inoculated comparisons at 5 and 10 DBP but no other treatments differed significantly. Rate of canopy closure (RAUCC) in FL1879 was significantly lower in non-treated inoculated comparisons at 5 and 10 DBP but no other treatments differed significantly in terms of RAUEPC. In Pike, RAUCC was significantly lower in non-treated inoculated comparisons at 5 and 10 DBP but no other treatments differed significantly. There was no significant difference in yield between any treatments. The total number of developing sprouts was least in the non-inoculated non-treated control and the treatment 8 and was significantly less than all other treatments. Maxim M Z (treatment 1) had the most developing sprouts but not significantly different from the non-treated inoculated control. No other treatments were significantly different form the non-treated inoculated control. The percentage of diseased sprouts was highest in the non-treated inoculated control, Evolve and Myconate (which was also non-treated). All other treatments had significantly fewer diseased sprouts in comparison to the non-treated inoculated control. Maxim M Z had significantly less seed-piece decay in comparison to the non-treated inoculated control but no other treatments were significantly different from the non-treated inoculated control. Myconate (foliar treatment) had maximum plant stand significantly more than the non-treated non-inoculated and the non-treated inoculated controls. No other treatments had significantly different plant stands from either control. The RAUEPC of the Myconate treatment was significantly greater than all treatments except 6% M ancozeb however no other treatments were significantly different for the non-treated non-inoculated and the non-treated inoculated controls. The RAUCC of the Myconate, 6% Mancozeb and Headsup treatments was significantly greater than the non-treated non-inoculated and the non- treated inoculated controls. No other treatments were significantly different in terms of canopy development from the non- treated non-inoculated and the non-treated inoculated controls. There was no significant difference in yield between any treatments. Although no significant on yield was determined in these trials, the non-treated inoculated control often had the numerically lowest yield. The use of a seed treatment effective against Fusarium sambucinum appears to be justified when cutting seed in advance of planting, however, cutting five DBP appears to have an effect on sprout development. This may be explained by the recovery of apical dominance in seed cut 10 DBP, in sprouts where the effect of apical dominance was removed by cutting. The effect is less easy to explain in seed cut 2DBP, in which sprout development was apparently unaffected by cutting. This effect also appears to be variety specific as it was not observed in Pike. Maxim MZ was the most effective seed treatment, significantly more effective against F. sambucinum than Moncoat MZ, Headsup and Mancozeb. Funding MPIC Table 1. Effect of timing of seed treatment application, cutting time (days before planting) and inoculation with Fusarium sambucinum on sprout health and development and potato seed-piece viability in two potato varieties. Seed piece decay (%)w Final plant stand (%) Timing of seed Variety Rate of Marketable Total emergence (RAUEPC)v Rate of canopy closure (RAUCC)u yieldt (cwt/A) Diseased sprouts (%)x number of developing sproutsy treatment application, cutting time (days before planting) and inoculation (+)z 26.0 e 10 10 10 5 5 5 2 2 2 10 10 10 5 5 5 2 2 2 yes yes no yes yes no yes yes no yes yes no yes yes no yes yes no 342 a 324 a 340 a 346 a 348 a 368 a 345 a 322 a 379 a 332 a 303 a 375 a 366 a 311 a 358 a 328 a 302 a 350 a 0.8 efg 5.7 ab 0.0 g 0.9 efg 2.0 de 0.0 g 1.0 efg 1.6 ef 0.0 g 0.5 fg 5.8 ab 0.0 g 0.7 efg 4.2 c 0.0 g 0.1 g 3.4 cd 0.0 g 30.3 cde 39.7 bc 0.0 h 10.3 ef 25.3 e 0.0 h 6.7 def 22.7 e 0.0 h 2.3 gh 63.0 a 0.0 h 4.0 gh 32.3 cde 0.0 h 2.7 ij 38.0 def 0.0 h FL1879 2.24 bcs FL1879 2.6 a FL1879 2.6 a FL1879 2.44 abc FL1879 1.6 e FL1879 1.92 de FL1879 2.44 abc FL1879 2.48 abc FL1879 2.12 cd 2.4 abc 2.56 ab 2.6 a 2.6 ab 2.68 a 2.68 a 2.64 a 2.4 abc 1.92 d Pike Pike Pike Pike Pike Pike Pike Pike Pike 100 a 87 cd 98 ab 91 abcd 91 abcd 95 abc 99 a 94 abcd 97 ab 94 abcd 75 d 96 abc 94 abcd 73 d 92 abcd 92 abcd 88 bcd 85 d 39.0 a 7.9 a 31.0 de 5.5 ef 36.0 ab 7.4 ab 36.0 ab 6 de 28.0 de 5.9 de 38.0 a 7.5 ab 7.6 ab 33.0 bcd 6.5 bcde 32.0 cde 7.3 abc 36.0 abc 7 abcd 35.0 abc 4.8 f 7 abcd 35.0 abc 40.0 a 7 abc 4.5 f 31.0 de 6.6 bcde 35.0 abc 6 de 33.0 bcd 31.0 cde 6 de 6.1 de 32.0 cd Treatment rate/cwt (seed treatment) 1 Maxim M Z 0.5 2 None 3 None 4 Maxim MZ 0.5 lb 5 None 6 None 7 Maxim MZ 0.5 lb 8 None 9 None 10 Maxim MZ 0.5 lb 11 None 12 None 13 Maxim MZ 0.5 lb 14 None 15 None 16 Maxim MZ 0.5 lb 17 None 18 None z Potato seed cvs. Pike and FL1879 was prepared for planting by cutting and inoculating with Fusarium sambucinum (dry rot) and treating with fungicidal seed treatments 2, 5 and 10days prior to planting. A treatment with no inoculation was included at each of the cutting dates. y Total number of developing sprouts per seed piece (n = 20) after 14 days incubation at 50oF. x Percentage dry rot affected sprouts per seed piece (n = 20) after 14 days incubation at 50oF. w Percentage development of dry rot on the seed piece (n = 20) after 14 days incubation at 50oF. v RAUEPC, relative area under the plant emergence progress curve calculated from the day of planting to full emergence at 29 days after planting (max = 100). u RAUCPC, relative area under the canopy development curve calculated from day of planting to key reference point taken as 50 days after planting (about 100% canopy closure) t Marketable yield, tubers greater than 2.5" in any plane (US1 grade). s means followed by same letter are not significantly different at P < 0.05 (Fisher’s LSD). r Foliar application of Myconate 0.02 oz/A at 95% emergence on 5 Jun in 25 gal water/A at 60 psi. Table 2. Effect of seed treatment and inoculation with Fusarium sambucinum on sprout health and development and potato seed-piece viability in potato variety Pike. Funding MPIC Inoculation (+)z Total Diseased sprouts (%)x Seed piece decay (%)w Final plant stand (%) Rate of emergence (RAUEPC)v Rate of canopy closure Marketable yieldt (cwt/A) yes yes no yes yes yes yes yes 2.7 d 38.0 b 0.0 d 46.0 b 12.0 c 61.3 a 13.7 c 16.0 c 0.1 c 3.4 b 0.0 c 1.0 bc 1.8 bc 5.6 ab 1.2 bc 0.8 bc 6 de 6 de 6.1 de 6.3 cde 6.2 cde 7.5 ab 6.4 cde 6.6 bcde 92 abcd 88 bcd 85 d 91 abcd 89 bcd 100 a 92 abcd 95 abc (RAUCC)u 33.0 bcd 31.0 cde 32.0 cd 36.0 ab 34.0 abc 38.0 ab 38.0 a 36.0 ab number of developing sproutsy 2.64 a 2.4 abc 1.92 d 2.24 bc 2.44 abc 2.32 abc 2.2 c 1.88 de Treatment rate/cwt (seed treatment) rate/A (foliar) 1 Maxim MZ 0.5 lb 2 None 3 None 4 Evolve 0.5 lb/cwt 5 Moncoat MZ 0.75 lb 6 Myconate 0.02 ozj 7 Headsup 3WDG 0.1 lb 8 6% Mancozeb 1lb z Potato seed cvs. Pike was prepared for planting by cutting and inoculating with Fusarium sambucinum (dry rot) and treating with fungicidal seed treatments 2 days prior to planting. y Total number of developing sprouts per seed piece (n = 20) after 14 days incubation at 50oF. x Percentage dry rot affected sprouts per seed piece (n = 20) after 14 days incubation at 50oF. w Percentage development of dry rot on the seed piece (n = 20) after 14 days incubation at 50oF. v RAUEPC, relative area under the plant emergence progress curve calculated from the day of planting to full emergence at 29 days after planting (max = 100). u RAUCPC, relative area under the canopy development curve calculated from day of planting to key reference point taken as 50 days after planting (about 100% canopy closure) t Marketable yield, tubers greater than 2.5" in any plane (US1 grade). s means followed by same letter are not significantly different at P < 0.05 (Fisher’s LSD). r Foliar application of Myconate 0.02 oz/A at 95% emergence on 5 Jun in 25 gal water/A at 60 psi. 328 a 302 a 350 a 372 a 333 a 380 a 387 a 379 a Funding MPIC and Industry POTATO (Solanum tuberosum L.‘Snowden’) Pink rot; Phytophthora erythroseptica Pythium leak; Pythium ultimum Late blight; Phytophthora infestans W. W. Kirk, R. L Schafer and D. Berry Department of Plant Pathology Michigan State University East Lansing, MI 48824 Evaluation of fungicides as soil applications at planting and foliar applications for pink rot and Pythium leak control, 2002. Soil was inoculated with mefenoxam-sensitive Pythium ultimum and Phytophthora erythroseptica at the Michigan State University Botany Farm, East Lansing, MI on 11 May 2000 and again on 17 M ay 2001; no further inoculum was applied in 2002. Potatoes (cut seed) were planted at the Michigan State University Botany Farm, East Lansing, MI on 17 May into four- row by 50-ft plots (34-in. row spacing) replicated three times in a randomized complete block design. The four-row beds were separated by a five-foot unplanted row. Plots were irrigated at planting and soil moisture was monitored with tensiometers. Water was applied as needed with seep-hose to maintain soil moisture at a minimum of 80% field capacity. After desiccation, plots were continuously watered to encourage tuber disease development caused by the inoculated pathogens. Plots were hilled immediately before foliar sprays began. Fungicides were applied in-furrow at planting at a rate of 5 gal/A (40 p.s.i.) applied at a rate using the conversion factor: Band rate per acre = [Band width (inches)/Row spacing (inches)] * Broadcast Rate per Acre. Thereafter fungicide treatments were applied as scheduled and late blight prevention maintenance treatments of Previcur 6SC 1.2 pt/A were applied weekly from 5 Jun to 15 Aug (10 applications) with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Weeds were controlled by hilling and with Dual 8E (2 pt/A on 28May) and Poast (1.5 pt/A on 17 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 17 May) and Sevin 80S (1.25 lb on 1 and 17 Jul). Plots were rated visually for percent emergence and percent canopy closure from planting to full emergence and full canopy closure respectively and a relative rate of development was calculated for both emergence and canopy formation. Prior to application of fungicides on 19 Jun, five plants were harvested from each replicate and the number of tubers greater than 0.25" (any plane) per plant was counted. Harvests were repeated on 16 Jul (Harvest 2); 14 Aug (Harvest 3) and11 Sep (Harvest 4) and tuber number and percent of tubers with symptoms of pink rot and/or Pythium leak were assessed. Symptomatic tubers were tested with Phytophthora and Pythium specific ELISA assays. Tuber number per plant and percentage of tubers per four-plant sample were compared using two-way ANOVA for comparison of treatments at individual harvest dates and two-way repeated measures ANOV A were used to compare if the metrics changed between harvests. Vines were killed with Reglone 2EC (1 pt/A on 15 Aug). Plots (50-ft row) were harvested on 11 Sep and individual treatments were weighed and graded (tubers less than 2.5 in width in any plane were discarded and only total marketable yield was reported). A further sub sample of 10 tubers per plot were challenge inoculated with each of Pythium ultimum, Phytophthora erythroseptica, Phytophthora infestans(all mefenoxam-sensitive isolates) or a sterile rye agar core by placing an 1/8" diameter core, taken from an axenic culture of each pathogen grown on rye agar, on the surface of the tuber at its apical end. The core was covered with a 1/4" diameter Eppindorf tube, the lid of which was cut off and dipped in petroleum jelly to adhere the tube to the tuber surface, to ensure a humid microenvironment. Tubers were cut open 28 days after inoculation and the percentage of tubers with symptoms of the diseases were calculated. Taking 35 days after planting (DAP) as a key reference point, no fungicide applied in-furrow delayed emergence in comparison with treatments that were not applied in-furrow in terms of the RAUEPC. Canopy formation (RAUCDC) was not affected by any in-furrow application of any fungicide. The in-furrow applications of fungicides were not phytotoxic. At harvest 1, prior to applications of foliar fungicides, there were about 10.3 + 0.91 (n = 300 plants) tubers per plant (greater than 0.25” any plane) and no significant differences between any treatments. The total number of tubers decreased in all treatments to 6.2 + 0.71, 5.8 + 1.00 and 4.5 + 0.66 after harvests 1, 2 and 3, respectively (n = 300 plants, average of all treatments) , but there were no significant differences between treatments at harvests 2 to 4. At the final harvest (h4), all treatments except 10 and 17 had significantly more tubers than the untreated control. Tuber number decline was compared within treatments. There was a significant decline in tuber number in all treatments from harvest 1 to 4. There was generally no significant difference between harvest 2 and 3 for any treatment and treatments 3, 4, 6, 7, 8, 9, 11 and 19 did not significantly decline in tuber number between harvests 2 and 4.The percentage incidence of tubers with symptoms of pink rot or Pythium leak increased to harvest 3 then decreased at harvest 4 in all treatments. The untreated control had significantly more diseased tubers than all other treatments at harvests 2 and 3 but not at harvest 1 or 4. At harvest 2, treatment 5 had significantly more diseased tubers than treatments 1,7,9,10,11,12,13, 14, 15 and 18 but was not significantly different from any other treatment. At harvest 3, treatments 8 and 12 had significantly fewer diseased tubers than treatments 3 and 17 but were not significantly different from any other treatment. Percent incidence of diseased tubers was compared within treatments. A significant increase in percentage diseased tubers at harvest three occurred in treatments 1,4, 7, 9, 10, 11, 14, 15, 16, 17 and 18. The high incidence of diseased tubers at harvest 3 and subsequent decline at harvest 4 may have been a result of complete deterioration of infected tubers between the two harvests. Although a significant increase in incidence of Funding MPIC and Industry diseased tubers was reported at harvest 3 within treatments, the overall incidence [average of the h1 - 4 within treatments, Table 2)] was numerically lower than the non-treated control for all treatments. All treatments had significantly greater marketable and total yield than the nontreated control (Table 3). Treatments 10, 17 and 18 had significantly lower marketable yield than treatments with yield greater than 212 cwt/A. Treatment 10 and 17 had significantly lower total yield than treatments with yield greater than 283 cwt/A. Some disease developed in tubers challenge inoculated with each of Pythium ultimum, Phytophthora erythroseptica, Phytophthora infestans but no treatments had significantly different percentage incidence of diseased tubers in comparison with the nontreated control for any of the pathogens (Table 4). Mefonaxam-based products generally reduced the amount of tuber disease and tuber loss regardless of application timing or formulation type. Other products also reduced the amount of tuber loss and incidence of tuber disease. Tuber loss and incidence of tuber disease even in the best treatments in this trial, under highly conducive conditions for development of Pythium leak and pink rot , was still high with up to 60% tuber loss resulting in low yields. The use of mefenoxam not indeed any product for control of Pythium leak and pink rot under highly conducive conditions remains an issue and recommendations for application of any products aimed at controlling these diseases remains speculative.. Table 1. Treatment and rate/acre 1 2 Ridomil Gold 4EC 0.1 pt (A)w Ridomil Gold 4EC 0.1 pt (A) Ridomil Gold Bravo 6WP 2.0 lb (D) Ridomil Gold Bravo 6WP 2.0 lb (D,F) Ridomil Gold Bravo 6WP 2.0 lb (F,H) Ultra Flourish 2EC 0.2 pt (A) Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Fluorinil 76.4WP 2.0 lb (D) Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Fluorinil 76.4WP 2.0 lb (D,F) Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Phostrol 4SC 4.0 pt (D); 6.0 pt (F) 3 4 5 6 7 8 9 10 Gavel 75WDG 0.48 lb (A); 2.0 lb (B,C,F,H) 11 Messenger 3WDG 0.1 lb (A); 0.28 lb (D,F,H) 12 Ridomil Gold 4EC 0.1 pt + Messenger 3WDG 0.1 lb (A) 13 Ultra Flourish 2EC 0.2 pt (A) 14 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt + Funding MPIC and Industry Emergence and Canopy development RAUEPCy RAUCDCx 0.33 0.36 0.36 0.38 0.35 0.39 0.35 0.38 0.35 0.36 0.37 0.38 0.37 0.37 0.38 0.36 0.38 0.37 0.38 0.38 0.013 0.20 0.19 0.20 0.19 0.20 0.20 0.21 0.19 0.20 0.19 0.20 0.20 0.21 0.20 0.20 0.21 0.20 0.19 0.19 0.19 0.008 % finalz 91.4 95.6 96.4 93.3 93.3 93.1 94.4 90.0 90.0 93.9 89.4 91.9 94.4 93.3 92.2 93.9 91.9 92.2 91.7 96.7 1.9 Acrobat 50WP 0.08 lb(A) 15 Acrobat 50WP 0.08 lb (A) 16 Headsup 3WDG 0.1 lb (A); 0.28 lb (D,F,H) 17 Summerdale I + II RATE 1 (A) 18 Summerdale I + II RATE 2 (A) 19 Summerdale I + II RATE 3 (A) 20 Untreated sem P = 0.05w z Percent emergence calculated as percent of maximum possible emergence in 2 x 50' rows. y Relative Area Under the Emergence Progress Curve from planting until 95% emergence [35 days after planting (dap)] in untreated control (max = 1). x Relative Area Under the Canopy Development Curve from planting until 100% canopy cover (53 dap) in untreated control (max = 1). w Application dates: A= 17 May (in-furrow at planting, Band rate per acre = [Band width (inches)/Row spacing (inches)] * Broadcast Rate per Acre) in 5 gal water/A; (foliar applications B - K), B= 5 Jun; C= 12 Jun; D= 19 Jun; E= 3 Jul; F= 17 Jul; G= 4 Aug; H= 15 Aug. u Standard error of mean included if no significant difference was calculated in ANOVA. Table 2 harvest 1z Tuber number per plantz harvest 2 harvest 3 harvest 4 harvest 1 Tubers with Pythium and/or Pink Rot (%)z harvest 4 harvest 2 harvest 3 Funding MPIC and Industry average harvest 1 to 4 (standard error) 3.9 5.95 5.2 3.64 6.0 6.40 4.7 6.69 4.4 4.22 4.2 5.74 2.8 4.36 2.9 1.67 B A A B A A B A 1.3 c B 12.7bcd A 1.4 a 9.7 cd A 6.2 bc A 9.3 cd A 0.0 bc A 14.6bc A 2.7 bc B 7.7 b 8.2 cd A A 2.5 bc A 12.7bcd A 1.2 a 1.4 a 1.5 a 1.5 a 1.6 a 0.0 c B 9.2 cd A 2.1 a 1.5 bc A 4.8 d A 1.4 a B A A B A A B A AB 0.0 c AB 0.0 c 0.0 c A C 0.0 c 0.0 c B B C A C B 12.6bcd A 8.3 cd A 5.3 cd A 3.9 d A A 5.0 d 1.4 a 2.3 a 2.1 a 1.9 a 1.7 a 1.5 bc A 1.2 c B 0.0 c B 2.7 bc B 0.0 c B 3.1 bc B A B B B B B A 15.5a 6.4 cd A 10.7cd A 9.1 cd A 20.4b A 11.3bcd A 13.3bcd A A A 30.8a 1.0 a 2.1 a 2.1 a 1.5 a 1.0 a 1.7 a 3.0 a 0.58 B 4.9 5.64 BC 4.2 3.78 2.7 2.25 A B 1.5 1.88 1.7 2.36 B 3.0 2.43 A 4.3 4.35 B 2.8 4.30 B 6.1 9.55 B 3.1 5.49 B B 4.5 5.98 A 14.1 12.3 10.5aw Av 6.2 a 5.4 a B 4.2 ab C 0.0 a Treatment and rate/acre 1 Ridomil Gold 4EC 0.1 pt (A)x 2 Ridomil Gold 4EC 0.1 pt (A) Ridomil Gold Bravo 6WP 2.0 lb (D) 3 Ridomil Gold Bravo 6WP 2.0 lb (D,F) 4 Ridomil Gold Bravo 6WP 2.0 lb (F,H) 5 Ultra Flourish 2EC 0.2 pt (A) 6 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) 7 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Fluorinil 76.4WP 2.0 lb (D) 8 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Fluorinil 76.4WP 2.0 lb (D,F) 9 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Phostrol 4SC 4.0 pt (D); 6.0 pt (F) 11.4a 10.3a 10 Gavel 75WDG 0.48 lb (A); 2.0 lb (B,C,F,H) 11 Messenger 3WDG 0.1 lb (A); 0.28 lb (D,F,H) 10.5a 12 Ridomil Gold 4EC 0.1 pt + Messenger 3WDG 0.1 lb (A) 9.8 a 13 Ultra Flourish 2EC 0.2 pt (A) 9.8 a 14 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt + Acrobat 50WP 0.08 lb(A) 15 Acrobat 50WP 0.08 lb (A) 16 Headsup 3WDG 0.1 lb (A); 0.28 lb (D,F,H) 17 Summerdale I + II RATE 1 (A) 18 Summerdale I + II RATE 2 (A) 19 Summerdale I + II RATE 3 (A) 20 Untreated sem P = 0.05u 9.5 a 9.7 a 10.3a 10.9a 9.9 a 10.2a 10.3a 10.9a 10.0a 11.0a 11.0a 10.3a 10.4a 10.1a 0.49 A A A A A A A A A A A A A A A A A A A 6.0 a 6.4 a 6.5 a 7.0 a 6.3 a 6.0 a 5.8 a 6.0 a 5.8 a 6.2 a 7.2 a 6.2 a 6.1 a 6.4 a 6.1 a 6.4 a 6.4 a 5.5 a 5.5 a 0.41 B B B B B B B B B B B B B 6.3 a 5.5 a 5.3 a 6.8 a 6.4 a 5.6 a 5.3 a 5.3 a 6.3 a 6.8 a 6.3 a 6.5 a 6.3 a B B 5.3 a BC 6.7 a 4.8 a B 6.0 a B 5.1 a B 4.3 a B 0.54 4.2 ab C B 4.6 ab B B BC 4.9 a C BC 4.5 ab C B B 5.1 a B B 5.1 a 5.0 a B B 4.7 a B B 3.9 bc C B B 4.4 ab B BC 4.6 ab C 4.6 ab C B 3.7 a 13.4a 0.0 a 0.0 a 0.0 a 0.0 a 3.7 a 5.6 a 6.4 a 3.5 a 0.0 a 0.0 a 3.1 a B 4.4 ab C 3.2 a C C 4.8 a 0.0 a B 4.8 a C 0.0 a BC 3.8 bc C 0.0 a 4.3 ab C B B B 0.0 a 4.7 a BC 6.9 a BC 3.0 c 2.21 z Five plants were selected at random from outside rows of each treatment plot on 18 Jun (Harvest 1, 1day prior to application of foliar fungicide on 19 Jun); 16 Jul (Harvest 2); 14 Aug (Harvest 3)and11 Sep (Harvest 4), tuber nu mber and percent of tubers with symptom s of pink rot and/or P ythium leak were assessed. S ymp tomatic tubers were tested w ith Phytophthora and P ythium specific E LISA assays. y Total and m arketable yield (cwt/A), tubers > 2.5" width in an y plane (estimated from 2 x 50ft row). x Application dates: A= 17 May (in-furrow at planting, Band rate per acre = [Band width (inches)/Row spacing (inches)] * Broadcast Rate per Acre) in 5 gal water/A; (foliar applications B - K), B= 5 Jun; C= 12 Jun; D= 19 Ju n; E= 3 Ju l; F= 17 Jul; G= 4 A ug; H= 15 Au g. w Values followed by the sam e lower case letter are not significantly differen t for treatment com parisons at P = 0.05 (Tukey M ultiple Com parison). v Values followed by the sam e upper case letter are n ot significantly different for harvest comparisons at P = 0.05 (Tukey Multiple C om parison); analyses com pleted after significant interactions com puted in com parison s of tuber num ber and percent incidence of d iseased tubers using a two-way repeated m easures AN OV A. u Stand ard error of mean included if no significant difference was calculated in A NO VA . Table 3. Treatment and rate/acre 1 Ridomil Gold 4EC 0.1 pt (A)y 2 Ridomil Gold 4EC 0.1 pt (A) Ridomil Gold Bravo 6WP 2.0 lb (D) 3 Ridomil Gold Bravo 6WP 2.0 lb (D,F) 4 Ridomil Gold Bravo 6WP 2.0 lb (F,H) 5 Ultra Flourish 2EC 0.2 pt (A) 6 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) 7 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Fluorinil 76.4WP 2.0 lb (D) Funding MPIC and Industry Yield cwt/Az Market-able Total 226 212 228 248 244 254 261 250 235 198 216 239 232 abx ab ab a a a a a a b ab a ab 254 253 278 296 273 303 304 297 284 235 267 278 279 ab ab ab a ab a a a a bc ab ab ab 8 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Fluorinil 76.4WP 2.0 lb (D,F) 9 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Phostrol 4SC 4.0 pt (D); 6.0 pt (F) 10 Gavel 75WDG 0.48 lb (A); 2.0 lb (B,C,F,H) 11 Messenger 3WDG 0.1 lb (A); 0.28 lb (D,F,H) 12 Ridomil Gold 4EC 0.1 pt + Messenger 3WDG 0.1 lb (A) 13 Ultra Flourish 2EC 0.2 pt (A) 14 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt + Acrobat 50WP 0.08 lb(A) 15 Acrobat 50WP 0.08 lb (A) 16 Headsup 3WDG 0.1 lb (A); 0.28 lb (D,F,H) 17 Summerdale I + II RATE 1 (A) 18 Summerdale I + II RATE 2 (A) 19 Summerdale I + II RATE 3 (A) 20 Untreated z Total and m arketable yield (cwt/A), tubers > 2.5" width in an y plane (estimated from 2 x 50ft row). y Application dates: A= 17 May (in-furrow at planting, Band rate per acre = [Band width (inches)/Row spacing (inches)] * Broadcast Rate per Acre) in 5 gal water/A; (foliar applications B - K), B = 5 Jun ; C= 12 Jun; D= 19 Ju n; E= 3 Ju l; F= 17 Jul; G= 4 A ug; H= 15 Au g. x Values followed by the sam e lower case letter are not significantly differen t for treatment com parisons at P = 0.05 (Tukey M ultiple Com parison). 264 288 288 226 255 283 183 220 239 236 181 205 224 146 ab a a bc b ab c ab a a bc ab a c Table 3. Treatment and rate/acre 1 Ridomil Gold 4EC 0.1 pt (A)y 2 Ridomil Gold 4EC 0.1 pt (A) Ridomil Gold Bravo 6WP 2.0 lb (D) 3 Ridomil Gold Bravo 6WP 2.0 lb (D,F) 4 Ridomil Gold Bravo 6WP 2.0 lb (F,H) 5 Ultra Flourish 2EC 0.2 pt (A) 6 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) 7 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Fluorinil 76.4WP 2.0 lb (D) 8 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Fluorinil 76.4WP 2.0 lb (D,F) 9 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt (A) Phostrol 4SC 4.0 pt (D); 6.0 pt (F) 10 Gavel 75WDG 0.48 lb (A); 2.0 lb (B,C,F,H) 11 Messenger 3WDG 0.1 lb (A); 0.28 lb (D,F,H) 12 Ridomil Gold 4EC 0.1 pt + Messenger 3WDG 0.1 lb (A) 13 Ultra Flourish 2EC 0.2 pt (A) 14 Ultra Flourish 2EC 0.2 pt + Phostrol 4SC 1.44 pt + Acrobat 50WP 0.08 lb(A) 15 Acrobat 50WP 0.08 lb (A) 16 Headsup 3WDG 0.1 lb (A); 0.28 lb (D,F,H) 17 Summerdale I + II RATE 1 (A) 18 Summerdale I + II RATE 2 (A) 19 Summerdale I + II RATE 3 (A) 20 Untreated sem P = 0.05x Funding MPIC and Industry Percent tubers with disease symptoms after challenge inoculationz Late blight P. infestans Pink rot P. erythroseptica Pythium leak Pythium ultimum 6.7 6.7 6.7 3.3 6.7 6.7 6.7 13.3 3.3 13.3 3.3 6.7 10.0 10.0 6.7 6.7 6.7 13.3 6.7 10.0 3.66 6.7 10.0 10.0 10.0 6.7 6.7 6.7 13.3 10.0 13.3 10.0 6.7 10.0 13.3 6.7 6.7 10.0 13.3 6.7 16.7 4.02 3.3 3.3 6.7 0.0 0.0 6.7 3.3 10.0 3.3 10.0 3.3 3.3 10.0 6.7 3.3 3.3 3.3 6.7 6.7 10.0 3.28 z Sub samples of 10 tubers per plot were challenge inoculated with each of Phytophthora infestans, Phytophthora erythroseptica and Pythium ultimum(all mefenoxam-sensitive isolates) or a sterile rye agar core by placing an 1/8" diameter core, taken from an axenic culture of each pathogen grown on rye agar, on the surface of the tuber at its apical end. The core was covered with a 1/4" diameter Eppindorf tube, the lid of which was cut off and dipped in petroleum jelly to adhere the tube to the tuber surface, to ensure a humid microenvironment. Tubers were cut open 28 days after inoculation and the percentage of tubers with symptoms of the diseases were calculated. y Application dates: A= 17 May (in-furrow at planting, Band rate per acre = [Band width (inches)/Row spacing (inches)] * Broadcast Rate per Acre) in 5 gal water/A; (foliar applications B - K), B= 5 Jun; C= 12 Jun; D= 19 Jun; E= 3 Jul; F= 17 Jul; G= 4 Aug; H= 15 Aug. x Inclusion of the sem (P=0.05) indicated that there was no significant difference among treatments. Funding: MPIC Control of Volunteer Potato (Solanum tuberosum) in a Corn (Zea mays) Rotation With Postemergence Herbicide Treatments. Chad D. Lee and Chris M. Long, Academic Specialist in Weed Science and Potato Specialist, Department of Crop and Soil Science, Michigan State University, East Lansing, Michigan 48824 Introduction Volunteer potatoes are an increasing problem in the lower peninsula of Michigan. One of the reasons that volunteer potatoes are an increasing problem is because there is the potential for 262,000 to 1,136, 000 tubers per acre to remain in the field after harvest (R. A. Boydston, unpublished data; Lumkes 1974; Lutman 1977; Perombelon 1975). Another reason for volunteer potato survival is winter soil temperatures above freezing. Soil temperatures in mid- Michigan during the 1999-2000, 2000-2001and 2001-2002 winters have not been below 32°F for a long enough period of time to freeze potato tubers (data from Montcalm County Extension). Volunteer potatoes may harbor diseases, nematodes and insects, which may infest subsequent potato crops. This concern is heightened in areas where the crop rotation interval is only two years. When volunteer potato plants are allowed to persist in rotational crops, many of the positive effects of crop rotation are lost (Boydston 2001). Volunteer potatoes are very detrimental to the Michigan seed potato industry as well. The potential for crop mixtures and virus vectoring by latent insects poses a problem for seed certification. The need for control measures to reduce or eliminate volunteer potatoes is critical. The volunteer potato lifecycle can extend over several years. The cycle begins in the initial crop year when potato tubers are deposited back into the field at harvest by a number of different avenues. There, the tubers over- winter due to the insulation of snow cover or due to the depth at which they are buried in the soil. The volunteer potatoes then sprout the following year unprotected by insecticide or fungicide in the rotational crop. If successful, the volunteer potatoes will reproduce and daughter tubers will over-winter again, leading to another generation of unwanted volunteer potatoes in the following crop. In many areas the following crop will be potato. Any possible pathogens that were contracted during the rotational year by the volunteer potatoes are now in the midst of the new potato crop. There are many different stages of the volunteer potato lifecycle. This suggests the possibility for various control tactics to reduce or prevent daughter tuber production. We examined one aspect of the volunteer potato lifecycle. We determined we could disrupt the daughter tuber lifecycle at emergence and growth prior to tuber set by herbicide applications. This led to the reduction or elimination of volunteer daughter tuber production during the current season of infection. Objectives Determine which herbicides are the most effective at controlling volunteer daughter tuber production. To achieve this objective, eight herbicides with activity on volunteer potatoes were examined. The herbicides used in this study are listed in Table 1. Most of these herbicides were evaluated alone and in a tank mixture with atrazine. Response of volunteer potatoes to these herbicide applications were evaluated 7 and 28 days after treatment. Tuber weights and numbers were recorded in September to determine herbicide impact on daughter tuber production. Table 1. Herbicides evaluated for control of volunteer potatoes. Herbicide Herbicide 1 Distinct 2 Tough 3 Buctril 4 Roundup 5 2,4-D 6 Starane 7 Callisto 8 Atrazine 9 Distinct + atrazine 10 Tough + atrazine 11 Aim + atrazine 12 2,4-D + atrazine 13 Callisto + atrazine 14 Starane + atrazine 15 Aim 16 Untreated Results Michigan State University evaluated the effectiveness of 15 postemergence herbicide treatments for volunteer potato control in corn in 2002. There are herbicides registered to control volunteer potatoes in wheat, such as Starane. (Starane is not registered for use in corn in Michigan). Callisto + atrazine and Distinct + atrazine provided the greatest volunteer potato control 7 days after application. By 28 days after application Callisto, Callisto + atrazine, Distinct and Distinct + atrazine provided the best control. These treatments stopped daughter tuber production. Therefore Callisto or Distinct, with or without atrazine, will help control volunteer potatoes in corn (Table 2). A fact sheet titled “VOLUNTEER POTATO MANAGEMENT” was published in December of 2002 and distributed to the Michigan Potato Industry. This fact sheet contains the findings from this project, as well as, general volunteer potato management strategies. Table 2. Postemergence herbicide applications in corn for volunteer potato control. Herbicides were applied on June 6, 2002 to volunteer potatoes that were 4-6 inches in height. APPLICATION POTATO DEFOLIATION DAUGHTER TUBERS DAUGHTER TUBER AFTER 28 DAYS PER PLANT* WEIGHT (OZ.) HERBICIDE TREATMENT CALLISTO COC + AMS CALLISTO + ATRAZINE COC + AMS DISTINCT + ATRAZINE ROUNDUP ULTRAMAX NIS + AMS DISTINCT NIS + AMS STARANE** ATRAZINE TOUGH ATRAZINE STARANE** 2,4-D AMINE AMS 2,4-D AMINE ATRAZINE AIM + NIS AIM ATRAZINE + NIS BUCTRIL ATRAZINE + COC TOUGH UNTREATED LSD0.05 RATE 3 OZ/A 1% V/V + 17 LB/100 GAL 3 OZ/A + 0.5 LB A/A 1% V/V + 8.5 LB/100 GAL 6 OZ/A + 0.5LB A/A 0.125% V/V + 17LB/100 GAL 0.125% V/V + 17LB/100 GAL 6 OZ/A 1.33 PT/A 0.5 LB A/A 24 FL OZ/A 0.5 LB A/A 1.33 PT/A 0.5 LB A/A 19 FL OZ/A 17 LB/100 GAL 0.5 LB A/A 0.5 LB A/A 0.33 OZ/A + 0.25% V/V 0.5 LB A/A + 0.25% V/V 0.33 OZ/A 1.5 PT/A 0.5 LB A/A + 1% V/V 24 FL OZ/A - 80 72 70 63 57 33 27 22 16 15 8 8 8 7 5 0 24 0.0 0.0 1.1 0.4 0.4 1.5 0.3 2.7 2.1 2.1 1.7 2 2.3 2.4 2.4 3.8 1.6 0.00 0.00 0.13 0.03 0.02 0.48 0.10 0.70 0.86 0.77 0.93 0.56 0.53 1.07 0.61 1.20 0.41 * An average number of tubers derived from three plants per replication and three replications per treatment. ** STARANE is not registered for use in corn. OZ/A = ounces per acre A/A = pounds of active ingredient per acre PT/A = pint per acre 1% V/V = 1 gallon per 100 gallons of spray solution 0.25% V/V = 1 quart per 100 gallons of spray solution 0.125% V/V = 1 pint per 100 gallons of spray solution MPIC Funding 2002 Report Integrated Control of Common Scab (Streptomyces scabies) in Potato I. Cultivar Resistance and Soil Moisture Treatments in Greenhouse and Field II. Inducing Resistance in Potato to Common Scab in Field Experiment III. Quantification of Pathogenic S. scabies in Greenhouse Experiment Experiments 2002 Report to MPIC Dr. D Fulbright E. C. P. Hollister1, Dr. R. Hammerschmidt1, Dr. W. Kirk1, Dr. D. Douches2, and 1Department of Plant Pathology, Michigan State University 2Department of Crop and Soil Science, Michigan State University Introduction The incidence and severity of common scab in North America is increasing due to the use of susceptible cultivars, and conducive cultural and environmental factors, such as rotation and soil moisture. Common scab of potato is caused by several gram-positive filamentous species of Streptomyces, but Streptomyces scabies is the predominant causal agent. S. scabies is an aerobic, soil-borne bacterium that causes a range of symptoms on the surface of potato tubers including superficial cork-like lesions, erumpent cushion-like raised scab, or pitted lesions, which extend through the tuber periderm into the cortex and vascular storage parenchyma. This bacterium is the most important plant pathogen in the genus Streptomyces worldwide and common scab of potato ranks fourth in severity of potato diseases. Although it has a relatively small yield impact, it significantly reduces marketability. The bacterium is introduced into fields on infected seed potatoes, but is persistent and survives indefinitely in soil, and can be distributed by soil water, wind and farm equipment. S. scabies can infect root crops such as radish, carrot, beets, turnip etc. and survives best in soils at pH 5.5 - 7.5, which is also the optimal pH for growing underground vegetable crops. Short rotations between susceptible crops increase the pathogen population and severity of the disease. Potato tubers are most susceptible to infection during early tuber development, since tubers are infected through stomata and immature lenticels yet to form a protective barrier. Mature tubers with well-developed skin are not susceptible to infection. However, infections established when the tubers are immature, expand as the tubers enlarge and lesions increase in severity over the season. S. scabies is favored by warm, dry soil at the time of tuber infection. The environmental influences on cultivar susceptibility to different strains are unknown. One of the most important management strategies in controlling potato scab is maintenance of adequate soil moisture. Irrigation impacts control of plant pathogens through effects on the physical environment of the soil and the plant surface1. Water applied early in the season to soil was shown to reduce common scab on susceptible cultivars4. Maintaining adequate soil moisture near field capacity during tuber initiation and early tuber development may aid in control. The interaction between irrigation practices and cultivar resistance on scab incidence and severity of tubers, and their affects on the population dynamics of the strains of the Streptomyces sp. in the soil is not well understood. Additionally, MPIC Funding 2002 Report quantification of the pathogen in soils has not been determined in relation to inoculum associated with infection. Although there are no effective chemicals available for controlling common scab, there are biological agents used on other plant-pathogen systems that have been effective in providing immunity against infection by a broad range of pathogens. This phenomenon is known as systemic acquired resistance (SAR). SAR occurs when a plant is treated with a chemical, an elicitor, or an incompatible pathogen, and the plant is subsequently able to send signals to biochemical pathways that are related to plant defense. These non-specific defensive symptoms can be effective in suppressing pathogens, changing the chemistry of the cell wall and cuticle, and producing antimicrobial compounds for additional protection against a broad range of pathogens. It has been well documented in cucumbers with protection against a wide range of pathogens and as well in the Solanaceous plant family, with protection of tobacco against tobacco mosaic virus5. It has not yet been determined if there are any biological agents that may reduce the occurrence and severity of common scab of potato. I. Objectives 1. Investigate the effect of varying soil moisture levels on scab incidence and severity of tubers in a controlled environment and the field. 2. Investigate the effect of cultivar resistance on scab incidence and severity of tubers in a controlled environment and the field. II. Objectives 1. Investigate the effect of four biological agents on common scab incidence and severity. 2. Investigate the effect of two different application methods of the biological agents on common scab incidence and severity. III. Objectives 1. Quantify the amount of pathogenic S. scabies in soil populations from greenhouse experiment. Methods I. Objectives 1. Investigate the effect of varying soil moisture levels on scab incidence and severity of tubers in a controlled environment and the field. 2. Investigate the effect of cultivar resistance on scab incidence and severity of tubers in a controlled environment and the field. In greenhouse experiments, soil boxes compartmentalized into sections (1’x 2’x3’) were filled with sand. The boxes were subjected to one of four soil moisture regimes varying from very low soil moisture to very high soil moisture in a completely randomized design. Soil was sterilized and subsequently inoculated with virulent S. scabies strains or treated with sterile water as a control prior to the experiment. Soil moisture probes, CS 615 Water Content Reflectometers (Campbell Scientific Instruments), were used to measure soil moisture and the data was recorded with CR10X data loggers. The boxes were planted to three varieties, two of which have been developed by the MSU Potato Breeding and Genetics Program, differing in susceptibility to common scab were: susceptible, cv Atlantic; moderately resistant, cv MSF373-8; and most resistant, MPIC Funding 2002 Report cv Liberator. Tubers were sampled after the skin had been fully developed for assessment of scab incidence and severity. In field experiment, potatoes (cut seed, cv. Atlantic, MSF373-8, and Liberator) were planted at the Michigan State University Botany and Plant Pathology Experimental Station, East Lansing, MI on 21 May into one-row by 120 ft-plots replicated 3 times and covered in black plastic to exclude additional rainfall in a split block design. All rows were irrigated until emergence and were inoculated (17 fl oz/120-ft row) with a suspension of Streptomyces strains at 106 CFU/fl oz on 30 May and repeated on 5 June. After emergence, irrigation schedules were empirically optimized to match greenhouse experiment irrigation treatments and volumetric soil moisture was verified with CS 615 Water Content Reflectometers (Campbell Scientific Instruments). Soil volumetric water content data was collected bi-weekly. Weeds were controlled by weeding, hilling and with Dual 8E at 2 pt/A 10 DAP, Basagran at 2 pt/A 20 and 40 DAP and Poast at 1.5 pt/A 58 DAP. Insects were controlled with Admire 2F at 1.25 pt/A at planting, Sevin 80S at 1.25 lb/A 31 and 55 DAP, Thiodan 3 EC at 2.33 pt/A 65 and 87 DAP and Pounce 3.2EC at 8 oz/A 48 DAP. Fungicides were applied weekly from 4 June to 7 September with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Fertilizer was drilled into plots before planting, formulated according to results of soil tests. Additional nitrogen (final N 28 lb/A) was applied to the growing crop with irrigation 45 DAP (days after planting). Plots were harvested on 10 September and individual treatments were evaluated based on scab incidence and severity. II. Objectives 1. Investigate the effect of four biological agents on common scab incidence and severity. 2. Investigate the effect of two different application methods of the biological agents on common scab incidence and severity. Potatoes (cut seed; cv. Snowden) were planted at the Michigan State University Muck Soils Experimental Station, Bath, MI on 7 June into two-row by 25-ft plots (34-in row spacing) replicated four times in a randomized complete block design. The two-row beds were separated by a five-foot unplanted row. All rows were irrigated until emergence and were inoculated (3.4 fl oz/25-ft row) with a suspension of Streptomyces strains at 106 CFU/fl oz on 13 August. Weeds and insects were controlled as described above at similar times. Applications of Messenger (Eden Bioscience), Elexa4 (Glycogenesis, Inc.), Myconate (VAMTech, L.L.C. ), and Heads Up (Northern Quinoa Corp. ) were applied according to specified labeled rate as in furrow and foliar treatment methods: In furrow applications of Messenger (0.42 lbs/A in 25 gal of water), Myconate (0.08 lbs/A in 25 gal of water), Elexa (11.83 pts/A in 25 gal of water) and Heads Up (0.15 lbs/A in 25 gal of water) were made over the seed at planting, applied with a single nozzle R&D spray boom delivering 5 gal/A (80 p.s.i.) and using one XR11003VS nozzle per row. Foliar applications of Messenger (1.7 lbs/A in 25 gal of water), Elexa (47.3 pts/A in 25 gal of water), Heads Up (.0.60 lbs/A in 25 gal of water) and Myconate (0.31 lbs/A in 25 gal of water) were made over the rows, applied with a single nozzle R&D spray boom delivering 25 gal/A (80 MPIC Funding 2002 Report p.s.i.) and using one XR11003VS nozzle per row on 15 and 22 July. Vines were killed with Reglone 2EC (1 pt/A on 20 September). Vines were killed with Reglone 2EC (1 pt/A on 20 September). Plots (25-ft row) were harvested on 27 September and individual treatments were evaluated based on scab incidence and severity. III. Objectives 1. Quantify the amount of pathogenic S. scabies in soil populations from greenhouse experiment. Soil samples were collected from each compartmentalized greenhouse box by obtaining approximately 300 g soil from tuber zone depth of soil. Large stones and plant debris were removed from each sample and DNA was extracted directly from 1 g of soil by the method of McVeigh et al. Primers derived from nec1, a pathogenicity factor gene in Streptomyces spp., were developed using Primer Express® Software (Applied Biosystems®). Primer and template concentrations were empirically optimized with SYBR Green PCR Master Mix and each sample was replicated 4 times and the trial was executed twice. Results In the greenhouse experiment, Atlantic at 10 percent volumetric water had average of approximately 10-25 percent of the surface area covered with scab. When the soil moisture was increased to 14 percent volumetric water content, the incidence of scab was reduced to an average cover of 8 percent. The 21 percent volumetric soil water demonstrated further reduction to less than 5 percent average scab per tuber, and the disease was eliminated at the highest soil moisture content. The average scab incidence for the intermediately susceptible cultivar, MSF373-8, at the 9 percent soil moisture had slightly more than 5 percent scab cover. The infections were less than 5 percent when the soil moisture was increased to 14 percent. When the volumetric soil moisture was increased to 21 percent and 29 percent, scab infection was absent. The least susceptible cultivar, Liberator had no scab infection at all four soil volumetric water contents. The field trial that mimicked the greenhouse experiments had less scab infection, but similar trends. The volumetric water contents were similar to the greenhouse experiments as the four irrigation treatments were within 2 percent of the corresponding treatment (Figure 2). Atlantic, the susceptible cultivar, had an average scab incidence of approximately 14 percent at the 10 percent volumetric soil moisture. When the soil moisture is increased to 16 percent, the average scab infections on the tubers was decreased to 9 percent. With 21 percent soil moisture, the average scab incidence was further decreased to approximately 6 percent, and with the 27 percent soil moisture, scab infections were decreased on average to less than 5 percent. The intermediately susceptible cultivar, MSF373-8, had an average scab cover of only 4 percent at the 10 percent volumetric water content. Scab infections were decreased by half when the water content was increased to 16 percent volumetric soil water. At 21 and 27 percent volumetric soil moisture, the average scab incidence was less than 1 percent. Scab infections on the least susceptible cultivar, Liberator, were less than 1 percent at all soil MPIC Funding 2002 Report Figure 1. Effects of volumetric water treatments on average scab development for susceptible (Atlantic), intermediately susceptible (MSF373-8) and least susceptible (Liberator) in greenhouse experiment. ATLANTIC MSF373-8 LIBERATOR 10-25 5-10 0-5 0 10-25 5-10 0-5 0 10-25 5-10 0-5 0 Inoculated Control Inoculated Control Inoculated Control r e v o C b a c S t n e c r e P Volumetric Water Content (%) 14 21 9 29 Figure 2. Effects of volumetric water treatments on average scab development for susceptible (Atlantic), intermediately susceptible (MSF373-8) and least susceptible (Liberator) in field experiment. Effects of Irrigation on Average Scab Severity: Field Results ) r e v o C % ( y t i r e v e S b a c S e g a r e v A 20 18 16 14 12 10 8 6 4 2 0 Atlantic MSF373-8 Liberator 10 16 21 27 Volumetric Water Content (%) MPIC Funding 2002 Report 20 20 15 15 5 5 0 10 10 25 25 30 30 ) r e v o C % Treatment In Furrow Method Elexa Heads Up Messenger Myconate Untreated Foliar Spray Method ( y t i r e v e S b a c S e g a r e v A Figure 3. Effects of four plant defense compounds and two application methods on average severity of scab on susceptible cultivar Atlantic. moisture contents. At 10 percent volumetric water content, the average scab cover was approximately 1 percent. The average scab severity was slightly decreased with the 16 percent volumetric soil water, and slightly increased with the 21 percent soil moisture treatment. When the soil moisture was further increased to 27 percent, the average scab incidence approached zero percent. In the natural chemical field trial, the in furrow application methods for Elexa and Myconate showed a slight decrease in scab infection when compared to the control, reducing the average scab severity from approximately 17 percent (infection of the control) to 11 and 12 percent cover, respectively (Figure 3). The in furrow applications of Heads Up and Messenger did not decrease the incidence of scab, but rather increased infections to 18 and almost 23 percent scab cover, respectively. The foliar spray method of Heads Up demonstrated a decrease in infection incidence by nearly half, to approximately 8 percent. The foliar applications of Elexa, Messenger, and Myconate either did not decrease scab incidence or increased the average scab severity of tubers. The preliminary results of quantification of pathogenic Streptomyces scabies from the greenhouse experiment showed that the samples clustered into two groups, where the mean quantity of DNA of the pathogen was low, 1e-7 pg/mL or was slightly higher at 1e-5 pg/mL. The soils that clustered in the low DNA group were either uninoculated treatments or were inoculated and treated with high soil moisture. The soils that were inoculated and treated with the two lower soil volumetric water contents had more DNA according to the preliminary assay. Conclusion The greenhouse experiment validates previous experiments and what others have shown, which is irrigation provides an effective means to control potato common scab4. It is evident that applying soil moisture will reduce the infection by the pathogen (Figures 1 MPIC Funding 2002 Report and 2). For both the greenhouse experiment and the field experiment, increasing the percentage of soil moisture reduced the infection. Also, the criticalness of cultivar selection has been demonstrated. The use of more resistant cultivars reduced scab infections when irrigation alone could not (Figure 2). In the greenhouse, the resistant cultivar showed no signs of infection by S. scabies at all soil moistures. This may infer that the least susceptible cultivars may need less irrigation than the more susceptible cultivars to avoid infection. In the field experiment, the resistant cultivar had little infection, regardless of scab infection. At this time the interaction of genotype x environment has not yet been determined at what soil moisture the least susceptible cultivar would become susceptible to scab infection. More experiments must be conducted to further understand this phenomenon between the host, pathogen, and the environment. These must be continued in the controlled environment and also in the field to assure applicability to the industry. The biological agents used in the field to induce resistance against the pathogen provided no protection. All treatments of the four natural elicitors did not prove to be efficacious and in fact, some control treatments had less scab infection than the biological treatments. Although these were not effective, there should be more tests of other products that may induce resistant to common scab. Additionally, the effects of experiments using more frequent applications and in conjunction with irrigation to suppress the pathogen may provide effective have not been demonstrated. The preliminary quantification results suggest that the pathogen seems to grow better in the drier environment, as evidenced by DNA quantification. References 1. Cook, R.J. and Baker, R.J. 1983. The Nature and Practice of Biological Control of Plant Pathogens. American Phytopathological Society: St. Paul, 416-421. 2. Elesawy, A.A., and Szabo, I. M. 1979. Isolation and Characterization of Streptomyces scabies Strains From Scab Lesions of Potato Tubers: Designation of the Neotype Strain of Streptomyces scabies. Acta Microbiologica Academiae Scientarum Hungaricae. 26, 311-320. 3. Hooker, W.J. 1981. Compendium of Potato Diseases. American Phytopathological Society: St. Paul, 33-34. 4. Lapwood, D.H., Wellings, L. W., and Hawkins, J. H. 1973. Irrigation as a Practical Means to Control Potato Common Scab (Streptomyces scabies): Final Experiment and Conclusions. Plant Pathology. 22: 35-41. 5. Lucas, J.A. 1998. Plant Pathology and Plant Pathogens. Blackwell Science. United Kingdom, 160-164. 6. McVeigh, H.P., Munro, J., and Embley, T.M. 1996. Molecular evidence for the presence of novel actinomycete lineages in a temperate forest soil. Journal of Industrial Microbiology. 17: 197-204. Funding: Federal Research Project MPIC 2002 Nematode Research Annual Report Michigan Potato Industry Commission George W. Bird Department of Entomology Michigan State University Potato Early-Die Resistance/Tolerance Research.- Twenty-one potato lines/varieties were evaluated in 2002 for tolerance or resistance to potato early-die. F 349-Y (Rose Gold x WI 877) exhibited resistance characteristics in 1998, 2000 and 2001. It yielded well in 2002 under early-die conditions; however, there was more nematode reproduction than in previous years. There is a possibility that the early-die resistance could be related to the Actinomycetes associated with this line. E 228-1 exhibited characteristics of tolerance in 1998, 1999, 2000 and 2001. It was not evaluated in 2002. The parents, Russet Nugget and Spartan Pearl need to be evaluated in relation to resistance to potato early-die. Eight additional lines/varioeties appeared to be tolerant to potato early-die in the 2002 trial (Tables 1,2,4 and 5). These include Bannock Russett and Michigan Purple in addition to lines from New York, Wisconsin and Michigan. All three of these states have similar potato early-die disease complexes Seven lines designated as potentially tolerant in previous years were not evaluated in 2002. Nine varieties (Atlantic, Goldrush, Jacqueline Lee, Liberator, Onaway, Pike, Russett Norkotah, Snowden and Superior) and two lines (E-149-Y5 and F099-3) have been designated as susceptible to potato early-die (Table 5). Two additional lines tested in 2002 were put in the probably susceptible category and eleven additional lines not tested in 2002. Observations related to six other lines are inconclusive. An additional three lines in this category were not evaluated in 2001. Based on multiple-year performance, data for four of the varieties/lines evaluated were inconclusive. Four lines not evaluated in 2001 have previously been placed in the inconclusive category. Observations about all of the lines/varieties tested since 1998 are recorded in Table 6. Cover Crop Research.- Various cover crops were evaluated in 2002 in relation to their suitability for control of root-lesion (Pratylenchus penetrans), northern root-knot (Meloidogyne hapla) and sugar beet cyst (Heterodera schachtii) nematodes. Nematode reproduction on cover crops is variety specific (Tables 7-9). Cover crop breeding programs designed to develop nematode trap crops have resulted in spectacular results for control of the sugar beet cyst nematode (Table 10). Tillage System/Soil Quality Research.- The 10-Year-Term Potato Crop rotation trial funded by MPIC from 1991 through 2000 resulted in a new classification system for soil quality. This was presented to MPIC in 2002. Considerable interested has been generated in the system, which is the basis for much of the current MSU Nematology Research Program. It appears that much of the land at the Montcalm Potato Research Farm would be classified in Category IV (degraded soil that responds to management) and some sites as Category V (degraded soil that does not respond to management. A long-term strategy needs to be developed at this site for soil quality restoration. Without potato early-die management, many areas on the farm yield 200 cwt or less. Based on these findings, a potato, wheat/clover, corn/clover system was initiated in 2001 to enhance the soil quality over a period of six-years. Alternative tillage systems (mold board plow vs chisel plow) was used as the major variable for the research project. It is beginning to appear that the highest tuber yields are associated with the chisel plow system (Table 11). This may be reflected by changes in the soil food web induced by the tillage system. 2002 data from the MSU Nematology Program indicates that most of the microbes and associated nematodes are located in the litter layer (Figures 1 and 2). Nematode population density data are inclusive and will probably require complete nematode community structure assessment for an understanding the dynamics of the soil biology (Table 12). Soil Quality Research.- A long-term soil quality research project was started in 2001 in cooperation with Dr. Snapp. The project uses two ranges at the Montcalm Potato Research Farm and consists of site consists of 72 plots. The 2001 objectives were to establish base-line information about the quality of the soil using a system of nematode community structure analysis. Research conducted by the MSU Nematology Program throughout Michigan, Iowa, Pennsylvania and Canada has shown this procedure to be highly sensitive in detection of soil quality differences among farming practices and locations. Because nematodes are involved in many different aspects of the below-ground food webs, their reproduction amplifies what is going on in the system and can be used for assessment of soil quality. The current hypothesis is that most Michigan soils should have a total nematode population density of between 500 and 3,000 per 1000 cm3 soil. The population, however, must be composed of a mixture of the different types of feeding groups, including significant number of bacterial and fungal feeding nematodes. After the initial baseline analysis of the research site, the entire area was fumigated with 75 gpa of metham. This was done so the research could be initiated under uniform soil conditions. Total nematode population densities were reduced more than 50% with the soil fumigation (Figure 3). By the end of the growing season, population densities were about twice what they were prior to soil fumigation. There was a significant decline in the population density during the winter months. The population dynamics associated with the bacterial feeding nematodes was similar to that of the total population (Figure 4). Although it took longer for the fungal feeding nematodes to rebound, the 2002 early- season population density was higher than the final 2001 fall density (Figure 5). The soil fumigation reduced to plant feeding nematodes to an almost non-detectable level (Table 6). They had, however, recovered by the end of the 2001 growing season. The omnivores (Figure 7) and the carnivores (Table 8) were most seriously impacted by soil fumigation. This was expected because of their food chain roles and overall nature of their life cycles. The research site was also used to evaluate the research sampling protocol used at the Montcalm Potato Research Farm. Six soil cores combined into a single sample was adequate for determination of the population densities of most types of nematodes (Figures 8-9). Population densities of plant feeding nematodes; however, were under estimated using this procedure (Figure 10). The nematode population density information from dividing each 4-row by 50 foot plot into two subplots was not significantly different from dividing the research unit into four subplots. Precision Agriculture Research.- Most of the progress on the potato precision agriculture research project was associated with the soil quality/rotation site at the Montcalm Potato Farm. It is imperative that the project be completed in the near future. Resources exist for a conference. AS indicated at the MPIC meeting last summer, ist is possible that the meeting could have a water resources component. Table 1. 2002 Michigan State University Potato Early-Die Nematode Tolerance- Resistance Research Late Season Foliage Index. ____________________________________________________________________ Variety/Line Late Season Foliage Index (0-5) Non-Fumigated Fumigated Difference 1. MSE202-3 Rus 2. Jacqueline Lee 3. Goldrush 4. Bannock Russet 5. Russet Norkotah 6. MSF349 1RY 7. Atlantic 8. NY 120 9. MSG227-2 10. ND5084-3R 11. MSF099-3 12. 13. Michigan Purple 14. MSH094-8 15. 16. 17. 18. 19. MSH095-04 20. W1201 21. Superior +1.25(0.04) +0.74(0.15) +0.50(0.09) +0.20(0.20) +3.50(0.09) +0.20(0.36) +0.45(0.09) +0.95(0.13) +0.50(0.09) +1.25(0.11) +0.75(0.11) +1.25(0.10) +1.20(0.10) +0.00(0.50) +0.70(0.11) -0.05(0.50) +0.95(0.05) +1.00(0.13) +0.75(0.03) +0.00(n.a.) +0.75(0.11) ______________________________________________________________________ 4.25cd 3.25bc 1.5a 5.0a 4.5cd 4.5cd 3.25bc 3.75bc 3.5bc 4.75cd 3.75bc 3.75bc 4.0c 3.0b 4.0c 1.75a 3.25bc 3.5bc 3.25bc 4.0c 1.75a 3.0c 2.5bc 1.0a 4.8d 1.0a 4.3d 2.8c 2.8c 3.0cd 3.5cd 3.0c 2.5bc 2.8c 3.0c 3.3c 1.8ab 2.3bc 2.5bc 2.5bc 4.0d 1.0a NY112 Onaway Snowden Pike Liberator 1. MSE202-3 Rus1,3 2. Jacqueline Lee 3. Goldrush1,2,3 4. Bannock Russet 5. Russet Norkotah 6. MSF349 1RY 7. Atlantic 8. NY 1202 9. MSG227-2 10. ND5084-3R 11. MSF099-31,3 12. Liberator1 13. Michigan Purple 14. MSH094-81 15. NY112 16. Onaway1,2,3 17. Snowden2 18. Pike 19. MSH095-041,2,3 20. W1201 21. Superior1,2,3 22.2 31.6 24.0 32.3 19.0 38.0 25.3 29.9 16.0 31.0 21.1 22.6 32.2 18.4 22.0 31.1 24.2 15.5 27.1 29.3 20.6 28.8 47.9 32.3 40.9 22.6 46.9 28.7 32.1 17.8 41.7 27.4 32.4 42.6 21.9b 21.7 46.5 27.6 19.5 38.0 27.0 29.9 +6.6(0.002) +16.3(0.02) +7.3(0.04) +8.6(0.13) +3.6(0.19) +8.9(0.12) +3.4(0.25) +2.3(0.34) +1.9(0.29) +10.7(0.07) +6.3(0.03) +9.8(0.08) +10.4(0.0.06) +3.5(0.07) -0.07(0.47) +15.4(0.0005) +3.2(0.14) +4.0(0.12) +10.9(0.05) -2.3(0.32) +9.3(0.02) Table 2. 2002 Michigan State University Potato Early-Die Nematode Tolerance- Resistance Research Tuber Yields. ____________________________________________________________________ Variety/Line Difference ____________________________________________________________________ ______________________________________ Non-Fumigated Tuber Yield Fumigated ______________________________________________________________________ 1Soil fumigation significantly (P = <0.05) A size tuber yield. 2Soil fumigation significantly (P = <0.05) Oversize tuber yield. 3Soil fumigation significantly (P = <0.05) total marketable tuber yield. Table 3. 2002 Michigan State University Potato Early-Die Nematode Tolerance- Resistance Research Scab Index. ____________________________________________________________________ Variety/Line _____________________________________________________________________ ______________________________________ Scab Index (0-5) Non-Fumigated Fumigated Difference - 1. MSE202-3 Rus 0.25(0.31) 1.00 0.75 3.75 0.25 0.50 2.00 5.00 3.75 2.0 1.75 3.75 3.00 2.25 4.00 1.75 2.50 1.75 3.25 2.25 2.50 2.00 2.00 2. Jacqueline Lee 3. Goldrush 4. Bannock Russet 5. Russet Norkotah 6. MSF349 1RY 7. Atlantic 8. NY 120 9. MSG227-2 10. ND5084-3R 11. MSF099-3 12. Liberator 13. Michigan Purple 14. MSH094-8 15. NY112 16. Onaway 17. Snowden 18. Pike 19. MSH095-04 20. W1201 21. Superior -0.50(0.10) -0.25(0.04) 0.00(0.50) +1.00(0.07) 0.00(0.50) -0.25(0.27) +0.50(0.34) +0.50(0.10) +0.25(0.17) +0.25(0.31) -1.50(0.003) -0.37(0.08) -0.12(0.40) +0.25(0.34) +1.25(0.001) 0.00(0.50) -1.00(0.10) -0.25(0.34) 0.00(0.50) -1.50(0.001) ______________________________________________________________________ 3.25 0.00 0.50 3.00 5.00 3.50 2.5 1.25 4.00 3.25 0.75 3.63 1.63 2.75 3.00 3.25 1.25 2.25 2.00 0.50 Table 4. 2002 Michigan State University Potato Early-Die Nematode Tolerance- Resistance Research Mid-Season Root-Lesion Nematode Population Densities. ______________________________________________________________________ Variety/Line ________________________________________________________________________ Pratylenchus penetrans per 1.0 gram of root tissue1 _________________________________________ Non-Fumigated Fumigated Difference -27.0 -12.0 1.5 -16.5 -23.8 1. MSE202-3 Rus 2. Jacqueline Lee 3. Goldrush 4. Bannock Russet 5. Russet Norkotah 6. MSF349 1RY 7. Atlantic 8. NY 120 9. MSG227-2 10. ND5084-3R 11. MSF099-3 12. Liberator 13. Michigan Purple 14. MSH094-8 15. NY112 16. Onaway 17. Snowden 18. Pike 19. MSH095-04 20. W1201 21. Superior 16.5 27.0 20.0 28.0 19.0 27.8 33.3 5.5 26.0 18.5 19.8 21.5 16.5 31.5 19.5 16.3 42.8 22.3 30.5 13.5 0.0 23.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -20.0 -28.0 -19.0 -27.8 -33.3 -5.5 -26.0 -18.5 -19.8 -21.5 -16.5 -31.5 -19.5 -16.3 -42.8 -22.3 -30.5 _______________________________________________________________________ 1Soil fumigation (P = < 0.001) Varieties/Lines (P = 0.994) Replicates (P= <0.001) Table 5. Summary of 2001 Michigan State University Potato Early-Die Nematode Tolerance-Resistance Research. _____________________________________________________________ Probable Resistance High yield in presence of potato early-die conditions and limited root-lesion nematode reproduction. MSF349-1RY (98, 00, 01, 02) Needs an additional year of data. Rose Gold x WI 877 Working with Dave Douches on the potentials of these lines since MSF349-1RY is highly susceptible to scab. It is possible that the extensive presence of the scab Actinomycetes could be related to the Potato Early-Die Disease Complex Response. Tolerant High yield in presence of potato early-die conditions with normal root-lesion nematode reproduction MSE228-1 (98, 99, 00, 01) Four years of consistent data. Russet Nugget x Spartan Pearl. Need to work with Dave Douches in detail on the parents. Probable Tolerance Two additional years of PED evaluation are needed for the following six potato lines/varieties. Bannock Russett (02) W1201 (02) NY 120 (01, 02) NY 112 (01, 02) MSG 227-2 (00 susceptible, 01 tolerant, 02 tolerant) MSH 094-8 (01, 02) MI Purple (00 tolerant, 01 susceptible, 02 tolerant) Lines/varieties not evaluated in 2002 MSE 028-1 (00) MSE 273-8 (00) MSF 018-1 (99, 00) MSF 060-6 (00) MSF 373-8 (98, 00) MSH 333-3 (01 W1431 (01) Table 5 (continued). Susceptible Low yields in presence of potato early-die conditions, normal or high root-lesion nematode reproduction, and good response to soil fumigation. Atlantic (97, 99, 00, 01, 02) MSE 149-5Y (98, 99, 00,01) MSF 099-3 (99, 00, 01, 02) Goldrush (02) Jacqueline Lee, MSG 274-3 (99, 00, 01, 02) Liberator, MSA 091 (01, 02) Onaway (01, 02) Pike (02) Russet Norkotah (02) Snowden (97, 99, 00, 01, 02) Superior (01, 02) Probable Susceptibility MSE 202-3 Rus (00, 01, 02) MSH 095-4 (01, 02) Not tested in 2002 MSB 076G-3 (01) MSB 106-7 (00) MSE 221-1 (00, 01) MSG 015-C (01) MSG 124-85 (00) MSH 026-3 Rus (01) MSP 81-11-5 (00) W1368 (01) W1386 (01) Inconclusive MSG 004-3 (00 susceptible, 01 tolerant) MSH 031-5 (00 tolerant, 01 susceptible) Not evaluated in 2001 MSB 107-1 (98 inconclusive, 99 susceptible, 00 tolerant) MSF 313-3 (98 susceptible, 00 tolerant) MSG 050-2 (99 possible resistance, 00 susceptible) MSE 048-2Y (98 possible tolerant., 99 susceptible, 00 susceptible) __________________________________________________________________ Table 6. Potato early-die line/variety observations. _______________________________________________________________________. Possible Resistance - MSF349-1RY (98, 00, 01, 02) Lowest root-lesion nematode reproduction in trial. Extremely high scab susceptibility. Tolerant - MSE228-1 (98, 99, 00, 01, 02) Second lowest root-lesion nematode reproduction in trial. Probable Tolerance - Bannock Russett (02) - MSB 107-1 (98 inconclusive, 99 susceptible, 00 tolerant) - MSE 028-1 (00) Scab tolerant. - MSE 273-8 (00) Root-knot nematode host. - MSF 018-1 (99, 00) - MSF 060-6 (00) Scab tolerant. - MSF 313-3 (98 susceptible, 00 tolerant) Scab susceptible. - MSF 373-3 (98, 00) Root knot nematode host. - MSG 227-2 (00, susceptible, 01 tolerant, 02 tolerant) - MSH 031-5 (00) Scab susceptible. - MSH094-8 (01, 02) - MSH 333-3 (01) - MI Purple (00, susceptible, 01 tolerant, 02, tolerant) Scab susceptible - NY 112 (01, 02) - NY 120 (01, 02) - W1201 (02) Highly Susceptible - MSE-149-5Y (98, 99, 00) Scab tolerant. - Atlantic (97, 99, 00, 02) Very good root-lesion nematode host - F099-3 (99, 00, 01, 02) - Goldrush (02) - Jacqueline Lee (02) - Liberator (02) - Onaway (01, 02) - Pike (02) - Russet Norkotah (02) - Snowden (97, 99, 00, 02) Very good root-lesion nematode host - Superior (01, 02) The standard of PED susceptibility! Susceptible Probable Susceptibility - MSA 091-1 (01) - MSB 076G-3 (01) - MSB106-7 (00) Root knot nematode host. Scab tolerant. - MSE 202-E Rus (00) Root knot nematode host. Scab tolerant. - MSE 221-1 (00) Excellent root knot nematode host. - MSF 099-3 (99, 00, 02) Scab susceptible. - MSG 050-2 (99 possible resistance, 00) Good root-lesion host. Table 6. Continued. - MSG124-85 (00) - MSG274-3 (99, 00) Scab susceptible. Probable High Susceptibility - MSE 048-2Y (98 possible tol., 99, 00) - MSG 004-3 (00) Excellent root-lesion nematode host. RK host. Scab tolerant. - MSP 81-11-5 (00) Excellent root knot nematode host. Scab susceptible. ________________________________________________________________________ Total Cysts 0.0 a 0.0 a WC 282 Vernal H. schachtii per 100 cm3 soil _____________________________________ Females Table 7. Influence of cover crop varieties on the reproduction of sugar beet cyst nematode (Heterodera schachtii). ___________________________________________________________________ Cover Crop (Variety) ___________________________________________________________________ Alfalfa Clover Oil Seed Radish Adagio Arena Colonel Rimbo Dackon Common Generic Cowpea Cabbage Soybean, 3.2 a 2.4 a 0.6 a 6.0 a 65.4 c 112.8 bc 51.6 bc 64.8 b Crimson Sweet Yellow, Blossom 2.6 ab 1.2 ab 1.0 ab 2.4 ab 47.4 bc 31.2 ab Early Jersey Wakefield 134.8 c 27.4 ab 160.2 c 5.8 a 3.6 a 1.6 a 8.4 a 0.0 a 0.0 a 0.4 a 0.2 a 0.2 a 0.0 a 0.0 a 0.0 a Red Ripper 0.6 a 0.2 a 0.0 a 0.7 a 0.7 a Kenwood 94 0.0 a 0.0 a 0.0 a 87.8 c Beta 5977 173.4 d 265.2 d Sugar Beet _______________________________________________________________ Trial B Mean 28 a 6 a 20 ab 95 b WC 282 Vernal Crimson Sweet Yellow, Blossom M. hapla per 100 cm3 soil _________________________________________ Trial A Table 8. Influence of cover crop varieties on the reproduction of the northern root-knot nematode (Meloidogyne hapla.. _______________________________________________________________________ Cover Crop (Variety) ________________________________________________________________________ Alfalfa Clover Oil Seed Radish Adagio Arena Colonel Rimbo Dackon Common Generic Cowpea Soybean Tomato, 334 510 bc 480 bc 312 2,340 c 1,734 105 330 bc 306 425 445 bc 158 ab 143 ab 1,128 bc 50 a 160 b 281 b 407 b 3,360 c 2,925 c 3,143 0 a 1,050 c 15,638 d 10,720 d 13,179 5 736 Kenwood 94 Red Ripper 24 51 10 a 421 b Rutgers 1,107 bc 8,150 d 4,629 ____________________________________________________________________ Notes on the host status of Potato and Sudax for M. hapla. - In general, most varieties of potato are similar to tomato in their suitability for reproduction of M. hapla - Sudax is a non-host for M. hapla. There should be no reproduction. 37 b 81 bc 43 b 86 WC 282 Vernal 1.0 g root Sum 6 a 5 a P. penetransl __________________________________ 100 cm3 soil Table 9. Influence of cover crop varieties on the reproduction of the root-lesion nematode, Pratylenchus penetrans. ________________________________________________________________ Cover Crop (Variety) ________________________________________________________________ Alfalfa Clover Oil Seed Radish Adagio Colonel Rimbo Dackon Common Generic Cowpea Cabbage _____________________________________________________________________ 29 ab 84 bc 81 c 217 c 100 bc 90 c 36 ab 3 a 30 ab 26 ab 3 a 29 ab 55 ab 136 c 51 ab 49 b 46 ab 27 ab 24 ab 9 a 2 a 5 a Crimson Yellow Blossom Sweet 29 ab 101 bc Early Jersey Wakefield 26 ab 14 a Red Ripper 72 bc Notes on the host status of Potato and Sudax for P. penetrans. - In general, most varieties of potato are fair hosts for reproduction of P. penetrans. This nematode, however, is pathogenic and also a predisposition agent for diseases complexes. - Sudax incorporated as a green manure crop at green pod stage provides P. penetrans control through its chemical degradation products. Yield 1.0 a 1.2 bc 1.7 d 1.3 bc 5.4 a 1.1 ab 1.6 cd 18.1 d 61.0 a 11.3 b 6.7 ab 15.01 c 14.96 c 83.8 bc 72.8 ab 99.7 cd 119.8 d 125.3 d No. Beets Wt./Beet (lbs) (tons/acre) Table 10 2001-2002 Oilseed Radish Sugar Beet Cyst Nematode Research Trial.1 _______________________________________________________________________ Cropping Sequence (2001) ________________________________________________________________________ Dry Beans/Oilseed Radish Dry Beans OSR/Dry Beans OSR/Fallow/OSR Fallow/OSR/OSR Oilseed Radish/OSR/OSR _______________________________________________________________________ 1Data based on six replications of two 50 ft rows spaced 30 inches apart. B J A 20.4 17.5 0.4 0.4 Total 380.2 0.333 1.000 0.233 0.307 106.5 196.0 142.5 247.0 Tuber yield (cwt) ______________________________________________________ Table 11. Influence of soil tillage on 2001 and 2002 potato tuber yields. ________________________________________________________________________ Tillage ________________________________________________________________________ 2001 Mold board plow Chisel plow T-test statistics 2002 Mold board plow Chisel plow T-test statistics ________________________________________________________________________ 0.2253 487.4 451.7 0.299 381.6 0.064 0.067 1.2 0.5 40.3 35.3 Root-Lesion Nematodes ________________________________________________ 1.0 g root tissue ________________________ 7/19/01 10/15/01 5/13/02 7/19/01 10/15/01 10/3/02 23a 65a 28a 100 cm3 soil Potato Wheat/clover Corn/clover 344a 124bc 185a 8a 99a 78b _____________________ Table 12. Influence of soil tillage and three agronomic crops on the population dynamics of the root-lesion nematode (Pratylenchus penetrans). Tillage/Crop Moldboard plow Chisel plow 130 a 1,550 270 ab ------ 316 b 1,820 169 a 1,730 278 ab ------ 960 529 b 351a 62b 261a 6a 284a 160c Potato Wheat/clover Corn/clover 39a 52 a 37a ----- 1,975 ----- ----- 1,841 ----- Funding: USDA/MPIC Potato Insect Biology and Management Report to the Michigan Potato Industry Commission January 16, 2003 Summary Beth Bishop, Ed Grafius, Adam Byrne, Walt Pett, and Eric Bramble Resistance to imidacloprid and thiamethoxam. For the first time, high levels of resistance to imidacloprid were found outside of Long Island NY. Colorado potato beetles from a commercial site in Delaware were over 100 fold resistant to imidacloprid and over 10 fold resistant to thiamethoxam compared to susceptible beetles and beetles from a commercial site in Pennsylvania were over 25 fold resistant to imidacloprid compared to susceptible beetles. Beetles originally collected in Montcalm Co. MI and selected for approximately 20 generations in the laboratory are over 100 fold resistant to imidacloprid compared to susceptible beetles, indicating the potential for resistance development in Michigan. Resistance to imidacloprid was highly correlated with resistance to thiamethoxam, although thiamethoxam resistance was at a much lower level, indicating that the benefits of rotating between the two for resistance management purposes will be limited. Effectiveness of registered and experimental insecticides. A number of registered and new insecticides provided excellent control of Colorado potato beetle. Mean numbers of large larvae per plant were reduced from 5.2 to 5.7 per plant in untreated plots to 0.3 larvae per plant or less in all treatments. Yields were 50 to 74 lb/45 ft in treated plots compared to 27 to 35 lb/45 ft in untreated plots. Duration of effectiveness of imidacloprid and thiamethoxam. Effective length of control for adult Colorado potato beetles was much longer on mineral soil than muck, as expected. Thiamethoxam, applied either to the seed or in furrow, provided somewhat longer control than imidacloprid on mineral soil. On muck soil, seed treatments provided longer control than in furrow applications for either product. A number of mid to late season problems were reported in 2002; these may relate to length of control as it is affected by rainfall and level of susceptibility of the Colorado potato beetle and the timing of movement of beetles into fields from overwintering sites or volunteers. Controlling aphids on potatoes with Fulfill® (pymetrozine). Significant mortality was caused by Fulfill treatment even for aphids placed on plants 8 days after application. Mortality did not reach high levels until 4 days after exposure. However, feeding stopped within 1 day of exposure to Fulfill in most situations. Fulfill is a highly effective material for aphid control but the delayed mortality will need to be considered when fields are sampled for effectiveness following treatment. Resistance to Imidacloprid and Thiamethoxam Imidacloprid (Admire, Provado) has been the predominant insecticide for Colorado potato beetle control since its registration in 1995. Such long term and widespread use of one compound greatly increases the chances for resistance development. In 2002, thiamethoxam (Platinum, Actara), a neonicotinoid like imidacloprid, but in a different chemical subclass, became available for commercial use. The similarities between these two compounds warrant careful scrutiny for resistance and cross-resistance development. The objectives of this study were to continue gathering data on baseline susceptibility to imidacloprid and thiamethoxam in Colorado potato beetle populations collected from Michigan and other regions of the United States. A second objective was to determine if susceptibility to thiamethoxam was correlated with susceptibility to imidacloprid. To accomplish these objectives, 24 Colorado potato beetle populations (7 Michigan populations, 13 populations collected in other states, and 4 laboratory populations) were bioassayed with imidacloprid and/or thiamethoxam (Table 1). Methods During 2002, seven Colorado potato beetle populations were collected from five different Michigan counties (Houghton, Mecosta, Montcalm, Newaygo, and St. Joseph). Syngenta representatives and other cooperators also provided one population each from Delaware, Maine, Pennsylvania, and Washington, two populations from Minnesota and New York and five populations from Wisconsin. Four populations maintained in the laboratory were also tested. One was a susceptible strain collected from the Upper Peninsula of Michigan in 1999 (Hughes). The second was a resistant strain collected from Long Island, New York in 1997 and maintained without selection. The third was a highly resistant strain collected from Long Island, New York in 1999 (Jamesport), also maintained without selection. The fourth was collected in 1997 from Montcalm County, Michigan and emergent adults from each generation were selected with imidacloprid (doses adjusted to target 60-80% mortality). Colorado potato beetle adults were either stored at room temperature and fed foliage daily or, for longer storage, kept in controlled environment chambers (11±1o C) and fed weekly. Beetles were treated with 1 µl of acetone/insecticide solution of known concentration applied to the abdomen using a 50 µl Hamilton microsyringe. Following treatment, beetles were placed in 100 mm polystyrene petri dishes lined with Whatman No. 1 filter paper and provided with fresh potato foliage. The petri dishes were kept at 25±1o C and the foliage and filter paper were checked daily and changed as needed. Each population was first screened to determine relative susceptibility to imidacloprid and thiamethoxam by testing 10 beetles each with three concentrations of insecticide/acetone solution. Based on the results of these screens, a range of five concentrations was selected for each population to be assayed and each bioassay was replicated up to three times. In each replicate, 10-15 beetles were treated with each concentration (three to five beetles per dish and two to three dishes per concentration). The responses of the beetles were assessed 7 days post treatment. A beetle was classified as dead if its abdomen was shrunken, it did not move when its legs or tarsi were pinched, and its elytra were darkened. A beetle was classified as walking if it was able to grasp a pencil and walk forward normally. A beetle was classified as poisoned if its legs were extended and shaking, it was unable to right itself or grasp a pencil, and it was unable to walk forward normally at least one body length. Data were analyzed using probit analysis (SAS System v8.01). Results The LD50 values for imidacloprid, 7 days post treatment, ranged from 0.016 µg/beetle (Hughes Farm) to 0.097 µg/beetle (Montcalm Farm) for Michigan populations and 0.029 µg/beetle (Hancock, WI) to 6.100 µg/beetle (Kujawski, NY) for out-of-state populations (Table 2). The values for the Michigan and out-of-state populations were consistent with those obtained for Colorado potato beetles in the same areas in previous years. The population from Little Creek, DE had an LD50 of 5.051 µg/beetle, which was the highest we have recorded away from Long Island, NY; it should be noted that we had not tested beetles from this area prior to this season. Laboratory population LD50 values for imidacloprid ranged from 0.031 µg/beetle (Hughes) to 2.809 µg/beetle (Evans). Resistance in the Little Creek DE population was 163 fold, compared to the susceptible Hughes laboratory strain (Figure 1). LD50 values for thiamethoxam, 7 days post treatment, ranged from 0.018 µg/beetle (Hughes Farm) to 0.077 µg/beetle (Rodney) for Michigan populations and 0.025 µg/beetle (Hancock, WI) to 0.468 µg/beetle (Deerfield, MA) for out-of-state populations (Table 3). The values for Deerfield, MA (0.468 µg/beetle), Kujawski, NY (0.431 µg/beetle) and Little Creek, DE (0.383 µg/beetle) were all much higher than the highest value recorded in previous seasons (0.194 µg/beetle from Kujawski, NY in 2001). Confidence limits were not obtained for these populations due to low sample size or high heterogeneity within the populations. All other field populations were consistent with previous seasons. Laboratory population LD50 values for thiamethoxam ranged from 0.044 µg/beetle (Hughes) to 0.241 µg/beetle (Jamesport). The relative susceptibility to imidacloprid (as measured by LD50) in Colorado potato beetle populations was significantly correlated with the relative susceptibility to thiamethoxam (Figure 2). That is, if an individual beetle strain had a high LD50 to imidacloprid, the LD50 to thiamethoxam was also somewhat high. This result was also found in 1998, 1999, and 2000. Now that thiamethoxam is registered and becoming widely used, we expect to see LD50s for thiamethoxam increase more rapidly. Table 1. Colorado potato beetle populations bioassayed for susceptibility to imidacloprid and thiamethoxam in 2002. Michigan populations Grant Adults were collected from volunteer potato plants in a commercial corn field in Newaygo Co. on 21 June 2002. Hughes Farm Adults were collected from an organic potato farm near Calumet, Houghton Co. on 2 July 2002. Johnson Adults were collected from a commercial potato field in St. Joseph Co. on 18 July 2002. Montcalm Farm Adults were collected from the MSU Potato Research Farm in Montcalm Co. on 11 and 13 June 2002. Rodney Adults were collected from a commercial potato field in Rodney, Mecosta Co. on 11 July 2002. St. Joseph Adults were collected from a commercial potato field in St. Joseph Co. on 18 July 2002. Syngenta Fourth instars were collected from the same commercial field in St. Joseph Co. as the St. Joseph population on 18 July 2002. Out-of-state populations Chetek, Wisconsin Adults were collected from a soy bean field, planted with potatoes in 2001, near Chetek, WI on 8 August 2002. Deerfield, Massachusetts Adults were collected from Savage Farm of South Deerfield, MA on 31 July 2002. Dilworth, Minnesota Adults were collected from untreated potatoes in a research plot near Dilworth, MN on 8 August 2002. Ephrata, Washington Adults were from a commercial farm near Ephrata, WA on 8 August 2002. Hancock, Wisconsin Adults were collected from the University of Wisconsin Hancock Research Farm on 20 August 2002. Kujawski, New York Adults were collected from Kujawski Farms of Jamesport, NY on 3 June 2002. Little Creek, Delaware Adults were collected from a field in Little Creek, DE on 25 June 2002. Miller, Wisconsin Adults were collected from Miller Farms, WI on 20 August 2002. Penn, Pennsylvania Adults were collected from a field in Sacramento, PA on 22 July 2002. Rose, New York Adults were collected from a research field in North Rose, NY on 29 July 2002. Rosemount, Minnesota Adults were collected from the Rosemount Research Station, Rosemount, MN on 13 June 2002. WC, Wisconsin Adults were received on 15 August 2002. WI-BC, Wisconsin Adults were received on 15 August 2002. Laboratory populations Evans Collected from Montcalm Co., MI in summer 1997. Adults from each generation were selected with imidacloprid doses targeting 60-80% mortality. Hughes Collected from an organic potato farm near Calumet, MI in July 1999. Maintained in the laboratory without selection. Jamesport Collected in the field on Long Island, NY in August 1999. Maintained in the laboratory without selection. Long Island Collected in the field on Long Island, NY in summer 1997. Maintained in the laboratory without selection. Strain 7 days post-treatment Table 2. LD50 values (µg/beetle, amount lethal to 50% of the population) and 95% fiducial limits for Colorado potato beetle populations treated with imidacloprid at 7 days after treatment. 95% fiducial limits LD50 0.023 0.016 0.097 0.056 0.127 0.092 0.034 0.029 6.100 5.051 0.132 0.704 0.091 0.039 0.096 2.809 0.031 2.196 0.018-0.027 0.014-0.018 0.077-0.137 0.003-0.218 0.080-0.105 0.024-0.041 0.022-0.036 Michigan populations Grant Hughes Farm Montcalm Farm Rodney out-of-state populations Chetek, WI Dilworth, MN Ephrata, WA Hancock, WI Kujawski, NY Little Creek, DE Miller, WI Penn, PA Rose, NY Rosemount, MN WC, WI laboratory populations Evans Hughes Long Island * 95% fiducial limits not available to do either low sample size or high heterogeneity 2.874-428.670 0.099-0.229 0.375-0.969 0.074-0.108 0.033-0.052 2.001-5.252 0.026-0.039 1.388-4.460 * * * Strain 7 days post-treatment LD50 Table 3. LD50 values (µg/beetle, amount lethal to 50% of the population) and 95% fiducial limits for Colorado potato beetle populations treated with thiamethoxam at 7 days after treatment. 95% fiducial limits 0.018 0.048 0.064 0.077 0.054 0.039 0.008-0.039 0.035-0.059 0.036-0.097 0.066-0.089 0.044-0.063 0.027-0.049 Michigan populations Hughes Farm Johnson Montcalm Farm Rodney St. Joseph Syngenta out-of-state populations Chetek, WI Deerfield, MA Dilworth, MN Ephrata, WA Hancock, WI Kujawski, NY Little Creek, DE Miller, WI Rose, NY Rosemount, MN WI-BC, WI laboratory populations Evans Hughes Jamesport Long Island * 95% fiducial limits not available due to either low sample size or high heterogeneity 0.054 0.468 0.060 0.049 0.025 0.431 0.383 0.053 0.082 0.034 0.065 1.64E-09-0.318 0.038-0.050 0.055-0.634 0.169-0.250 0.030-0.039 0.047-0.119 0.140 0.044 0.241 0.204 * * * * * 0.046-0.064 0.049-0.079 0.019-0.034 0.004-0.087 A. Imidacloprid 163 22 91 71 15 10 5 0 20 15 10 5 0 B. Thiamethoxam Figure 1. Resistance ratios of Colorado potato beetle strains to imidacloprid and thiamethoxam compared to the susceptible Hughes laboratory strain. * denotes high variability 0.6 0.5 0.4 0.3 0.2 0.1 0 A. y = 0.0624x + 0.0435 r2 = 0.952 0 2 4 6 8 imidacloprid LD50 (µg/beetle 0.1 B. 0.08 0.06 0.04 0.02 0 0.00 0.02 y = 0.3229x + 0.0241 R2 = 0.5157 0.06 0.04 imidacloprid LD50 (µg/beetle) 0.08 0.10 0.12 0.14 Figure 2. Correlation between susceptibility to imidacloprid and thiamethoxam. A. All populations. B. Only populations outside of Long Island with minimal variability and calculated fiducial limits (see Tables 2 and 3). Effectiveness of Registered and Experimental Insecticides Eighteen insecticide treatments (Table 4) were tested at the MSU Montcalm Research Farm, Entrican, MI for control of CPB. ‘Snowden’ potatoes were planted 12 inches apart with a 34- inch row spacing on 15 May. Treatments were replicated four times in a RCB design. Plots were 45 ft long and three rows wide. Eleven treatments were applied at planting. Admire 2F, Platinum 2SC, Platinum Ridomil Gold, and V10112 20SG(100 + 150 g ai/ acre) were applied as in-furrow sprays using a single nozzle hand held boom (30 gpa, 35 psi). Tops-MZ-Gaucho was applied as a dust to seed pieces prior to planting (in a plastic tub). Cruiser and Genesis were applied to seed pieces with 200 ml of water using a spray bottle, also prior to planting. Foliar treatments were first applied at approximately 80% CPB hatch on 18 Jun. Subsequent first-generation sprays for most treatments were applied on 25 Jun, 2 Jul, and 9 Jul (depending on treatment, Table 4). Post-spray counts of CPB adults and larvae (small and large) on five randomly selected plants from the middle row of each plot were made 2 days after each application. Defoliation ratings were taken on 1 Jul and 17 Jul by assessing five randomly chosen plants from the middle row of each plot. A maintenance spray of Agrimek (16 oz./A) was applied to all plots on 1 Aug to control summer adult CPB. On 10 Sep, the middle row of each plot was harvested mechanically, and the tubers were separated by size and weighed. Data were analyzed using two-way ANOVA (treatment and block) and significant differences were determined at the 0.05 level with Fisher’s Protected LSD test. Populations on the four sample dates averaged 5.2 to 5.7 large larvae per plant in untreated plots and 0.3 adults per plant. There were significant differences between treated and untreated plots in the seasonal means of small larvae, large larvae, and adults (Table 4). Treatments resulted in significantly fewer small and large larvae than in the untreated plots in nearly all cases. There were also significant differences between treatments in total yield and yield of size A potatoes (Table 5). Defoliation ratings were significantly lower for all treatments than for untreated plots on 1 Jul and 17 Jul. Table 4. Seasonal mean number of Colorado potato beetle egg masses, small larvae, large larvae, and adults per plant. Application dates Seasonal mean number of 1st-generation CPB/plant Large Larvae Adults 0.1ab 0.1a 0.1a 0.1a 0.1a 0.1a 0.1a 0.0a 0.0a 0.0a 0.1a 0.1a 0.0a 0.0a Small Larvae 1.2a 0.4a 0.2a 0.0a 0.0a 0.0a 0.0a Egg Masses 0.5 gh 0.5 fgh 0.0ab 0.1abc 0.0ab 0.0a 0.0ab 18 Jun, 9 Jul 18 Jun at planting at planting at planting at planting at planting Rate 1.5 oz./acre 3.0 oz./acre 12 fl. oz./acre 15 fl. oz./acre 19 fl. oz./acre 0.15 fl. oz./cwt. 0.60 fl oz./cwt. 0.75 lbs./cwt. 0.45 oz./1000 row ft. 0.55 oz./1000 row ft. 34 fl. oz./acre 4.5 fl. oz./acre 12 oz./cwt. 100 g ai/acre 150 g ai/acre 20 g ai/acre 20 g ai/acre 0.07% v/v 40 g ai/acre 40 g ai/acre 0.07%v/v Treatment/formulation Actara 25WG Actara 25WG Admire 2Fa Admire 2Fa Admire 2Fa Cruiser 5FSc Genesisc + TOPS MZb Platinum 2SCa Platinum 2SCa Platinum Ridomil Golda Spintor 2SC Tops-MZ-Gauchob V10112 20 SGa V10112 20 SGa V10112 20 SG V10112 20 SG + Silwet L-77 V10112 20 SG V10112 20 SG + Silwet L-77 Untreated check 1 Untreated check 2 Means within a column followed by different letters are significantly different (P<0.05, Fisher’s Protected LSD). atreatment applied in furrow at planting b treatment applied to seed pieces as dust before planting ctreatment sprayed onto seed pieces with a spray bottle and 200 ml water before planting at planting at planting at planting 18 Jun, 25 Jun, 2 Jul at planting at planting at planting 18 Jun, 2 Jul, 9 Jul 18 Jun, 2 Jul, 9 Jul 0.0ab 0.0a 0.0ab 0.4 efgh 0.0ab 0.0ab 0.0ab 0.3 def 0.2 bcd 0.0a 0.0a 0.0a 0.7a 0.0a 0.0a 0.0a 0.5a 0.7a 18 Jun, 2 Jul 18 Jun, 2 Jul 0.5 efgh 0.6 h 0.3 defg 0.3 defg 2.5 bc 3.5 c 1.3ab 1.0a 0.0a 0.0a 0.0a 0.0a 0.2a 0.0a 0.0a 0.3b 0.3b 0.2a 0.1a 5.7 b 5.2 b 0.0a 0.0a 0.0a 0.0a 0.1a 0.1ab 0.0a 0.0a 0.1a 0.1a 0.1a 0.3 c 0.3 bc Table 5. Mean yield (weight/45 row ft) harvested and defoliation ratings taken on two sampling dates. Yield (lb/45 row ft) Defoliation ratingc Size B 1 Jul 1.0a 1.1ab 1.0a 1.0a 1.0a 1.0a 1.1ab Size A 51.3 cd 61.1 cdef 60.3 cdef 69.4 ef 64.6 def 64.4 def 67.3 def Total 54.4 cde 64.9 cdef 63.1 cdef 73.0 f 68.4 def 67.7 def 71.8 ef Application dates 18 Jun, 9 Jul 18 Jun at planting at planting at planting at planting at planting Rate 1.5 oz./acre 3.0 oz./acre 12 fl. oz./acre 15 fl. oz./acre 19 fl. oz./acre 0.15 fl. oz./cwt. 0.60 fl oz./cwt. 0.75 lbs./cwt. 0.45 oz./1000 row ft. 0.55 oz./1000 row ft. 34 fl. oz./acre 4.5 fl. oz./acre 12 oz./cwt. 100 g ai/acre 150 g ai/acre 20 g ai/acre 20 g ai/acre 0.07 % v/v 40 g ai/acre 40 g ai/acre 0.07% v/v Treatment/formulation Actara 25WG Actara 25WG Admire 2Fa Admire 2Fa Admire 2Fa Cruiser 5FSc Genesis + TOPS MZb Platinum 2SCa Platinum 2SCa Platinum Ridomil Golda Spintor 2SC Tops-MZ-Gauchob V10112 20 SGa V10112 20 SGa V10112 20 SG V10112 20 SG + Silwet L-77 V10112 20 SG V10112 20 SG + Silwet L-77 Untreated check 1 Untreated check 2 Means within a column followed by different letters are significantly different (P<0.05, Fisher’s Protected LSD). a treatment applied in-furrow at planting b treatment applied to seed pieces as dust before planting c Defoliation rating: 1, no defoliation; 2, 1-25% defoliation; 3, 26-50% defoliation; 4, 51-75% defoliation; 5, 76-100% defoliation. at planting at planting at planting 18 Jun, 25 Jun, 2 Jul at planting at planting at planting 18 Jun, 2 Jul, 9 Jul 18 Jun, 2 Jul, 9 Jul 57.3 cdef 70.4 f 58.8 cdef 46.0 bc 70.0 ef 52.9 cde 66.0 def 54.1 cdef 59.1 cdef 61.4 cdef 73.9 f 63.1 cdef 49.5 bc 73.4 f 56.5 cdef 69.9 def 57.4 cdef 63.5 cdef 3.1 3.8 2.8 3.6 3.8 3.3 4.5 4.1 3.5 4.3 3.5 3.4 3.6 3.9 3.3 4.4 3.8 3.1 2.9 2.8 1.0a 1.0a 1.0a 1.0a 1.0a 1.0a 1.0a 1.3 b 1.6 c 1.1ab 1.2ab 18 Jun, 2 Jul 18 Jun, 2 Jul 34.8ab 26.7a 2.2 d 2.4 d 49.9 cd 58.5 cdef 31.9ab 23.9a 53.7 cd 61.6 cdef 17 Jul 1.0a 1.1a 1.0a 1.0a 1.0a 1.0a 1.0a 1.0a 1.0a 1.0a 1.2a 1.0a 1.0a 1.0a 1.1a 1.0a 1.0a 1.2a 2.4 b 3.1 b Duration of Effectiveness of Imidacloprid and Thiamethoxam Imidacloprid and thiamethoxam are mainly used at planting, either as in-furrow applications or seed treatments prior to planting. As for any soil insecticide, effectiveness declines as time goes by. The length of control will depend on initial application rate, the susceptibility of the pest, and environmental factors such as soil type and rainfall or irrigation. Our objectives were to see if the chemical used, the type of application, and the soil type interact to affect length of control. Methods Potatoes were planted at the Montcalm Potato Research Farm, on 15 May, as a part of the insecticide trial described above. A second planting was made at the Michigan State University Muck Crops Research Farm, Bath Michigan, on 21 May. Soil was McBride Sandy Loam at the Montcalm Farm and Houghton Muck (77% organic matter) at the Muck Crops Research Farm. Potatoes were planted and grown following standard commercial practices of fertilization, hilling, irrigation, and herbicide treatment. Application rates used were the maximum recommended commercial rates of imidacloprid or thiamethoxam, either applied in furrow at planting or as seed treatments, as described in the insecticide evaluation section above. Foliage was picked from treated plants in the field, placed in a cooler with ice and kept refrigerated until used on the next day. Foliage was also collected from untreated plants to correct for beetle mortality not due to insecticide. At the Montcalm Farm, foliage was collected to start the assays on12 and 26 June and 10 and 17 July (28, 42, 56, and 63 days after planting). At the Muck Farm, foliage was collected to start the assays on 19 June and 3 July (29 and 43 days after planting). Leaves with petioles in vials of distilled water were placed in petri dishes (5 dishes per treatment) and five CPB were added to each dish. Foliage was collected again from the field and replaced in the petri dishes after 2 days. Mortality was assessed after 4 days. Beetles were judged as dead or poisoned if they were unable to walk forward one body length. Treatment Admire 2F Gaucho Genesis Platinum 2SC Cruiser 5FS Active ingredient Application method imidacloprid imidacloprid imidacloprid thiamethoxam thiamethoxam in furrow seed treatment seed treatment in furrow seed treatment Rate 15 fl oz/A 12 oz/cwt 0.6 fl oz/cwt 0.55 fl oz/1000 row ft 0.15 fl oz/cwt Results At the Montcalm Farm, initial mortality at 28 days after planting (12 June) was 70 to 100% (Figure 3). Mortality declined rapidly in all but the Platinum treatment (thiamethoxam, in furrow). By 63 days after planting (17 July), mortality was less than 50% for all treatments. At the Muck Farm, with highly organic soil, control was less than 30% in the in furrow treatments even on the first sample date, 29 days after planting (19 June). Mortality in all treatments was at or near zero by 43 days after planting (3 July). This short residual activity is common for soil insecticides in muck soil; the organic material in the soil often binds with the insecticide, reducing effectiveness. In the muck soil, the seed treatments of both imidacloprid and thiamethoxam gave much better control than in furrow applications, likely due to less opportunity for soil binding. The interactions between application method and soil type indicate the complicated nature of soil/insecticide interactions. Usually, under commercial situations, any of the treatments studied would give effective control of overwintered adults, which generally arrive shortly after plant emergence. Small larvae are much more sensitive than adults, so larval control would be longer than the length of adult control observed in this study. Thus, control through the first generation would be expected. If there was little or no immigration of beetles into the field later in the season, no further insecticide treatment for Colorado potato beetle would be necessary. In 2002, there were a number of reports of mid to late season problems in Michigan and throughout the US. These may have been situations where adults arrived late into the field because of late emergence from overwintering or previous feeding on volunteer potatoes. Length of adult control would also be reduced if low levels of insecticide resistance were present in late-emerging adults. In addition, heavy rainfall shortly after planting could result in leaching of the chemical below the root zone and reduced length of control. In 2003 we hope to continue research into these interactions. 100.0 80.0 60.0 40.0 20.0 0.0 100 80 60 40 20 0 Montcalm Farm 25 35 45 55 65 Days after planting Muck Farm 25 35 45 55 65 Days after planting Admire Gaucho Genesis Platinum Cruiser Admire Gaucho Genesis Platinum Cruiser Figure 3. Length of control of adult CPB for imidacloprid and thiamethoxam formulations and application methods in sandy loam and muck soil. Length of larval control would be significantly longer. Controlling aphids on potatoes with Fulfill (pymetrozine). Several species of aphids colonize and flourish on potatoes, including the potato aphid (Macrosiphum euphorbiae) and the green peach aphid (Myzus persicae). Aphids are a sporadic pest; their numbers vary considerably from year to year. Aphid problems often begin late in the growing season. Overuse of insecticides such as pyrethroids, which kill natural enemies while only minimally impacting aphids, can lead to outbreaks. Green peach aphids especially, can quickly develop resistance to conventional insecticides, also leading to population build-ups. Once established, aphids reproduce rapidly on potato plants. They suck plant juices, deform foliage, reduce photosynthetic capacity and reduce yield. Aphids also transmit viruses, including potato leafroll virus and potato virus Y. Both are vectored by feeding of infected aphids. Potato virus Y is a nonpersistent virus, which means it is transmitted very quickly by many species of aphids and insecticides do not prevent its spread. Potato leafroll virus is a persistent virus which requires a period of incubation in the green peach aphid before transmission. Fulfill®, (pymetrozine, Syngenta) is a novel chemical control product that specifically targets aphids. Unlike conventional insecticides it paralyzes the muscles that allow the aphid to suck plant juices. Consequently, aphids exposed to Fulfill quickly cease feeding. After several days, aphids eventually starve to death. Because it has such a specific effect on a specific group, Fulfill does not affect natural enemies or beneficial insects. However, assessing efficacy of Fulfill is challenging since aphids may still be alive on the plant even though the insecticide is working. Several questions arise because of this novel mode of action—how long does it take for aphids exposed to treated foliage to die? How long after application is Fulfill effective against newly-colonizing aphids? —how long after application does the material inhibit feeding? The objective of this study was to address these questions by artificially infesting treated foliage with aphids at different time intervals after treatment and to evaluate the effects of Fulfill on feeding and mortality over time. Methods Aphids were obtained from a natural infestation on potted potato plants growing in a greenhouse. Foliage was obtained from six-week old potato plants (planted 24 Apr) that were grown in a separate (pest free) greenhouse. On 4 Jun 2002, 10 potted potato plants were sprayed with Fulfill 50 WG (2.75 fl. oz at 30 gpa using a hand-held CO2 sprayer). An additional 10 plants were set aside as untreated controls. After the spray had dried, five leaves (one from each of five different plants) were collected from both Fulfill-treated and untreated potato plants. The foliage was brought back to the lab and leaves were individually placed in water-picks. Each leaf was placed in a separate petri dish lined with filter paper (10 dishes total, five containing untreated foliage, five containing Fulfill-treated foliage. Aphids were transferred individually with paint brushes from infested plants onto leaves in petri dishes. Ten aphids were placed in each dish. After aphids were transferred, the dishes were sealed with parafilm. Additional sets of 10 dishes each were set up, as described above, on 5 June (1 day after treatment), 6 June (2 days after treatment), 7 June (3 days after treatment), 11 June (7 days after treatment) and 12 June (8 days after treatment). Aphids were examined each weekday after set up. The number of dead and live aphids were counted and dead aphids were removed. Each live aphid was classified, where possible, as feeding (mouthparts [stylets] inserted into leaf), walking on foliage, on foliage, but not feeding, or off of foliage. Foliage was replaced and necessary. The number of dead vs. live aphids each day was compared between Fulfill and untreated foliage using a X2 test (JMP statistical software). The number of live aphids feeding vs. not feeding was also tested. Results: In all cases, aphid mortality was higher on Fulfill-treated foliage than on untreated foliage (Table 6). Mortality was minimal on both treated and untreated foliage for the first day after exposure, but increased dramatically on the Fulfill-treated foliage after 3 to 4 days. After the first few days, mortality was significantly higher on Fulfill-treated foliage than on untreated foliage. Mortality on untreated and treated foliage increased significantly when dishes were left unchecked for several days (Table 6—after consecutive NE (not evaluated). Fulfill treatment had good residual and continued to cause significant aphid mortality even in aphids that were placed on foliage 7-8 days after the application was made (Figure 4). Fulfill inhibited aphid feeding dramatically (Table 7). In all cases, the percentage of live aphids that were feeding was lower (in many cases much, much lower) on Fulfill-treated foliage than on untreated foliage. In most cases, this difference was statistically significant. Feeding was inhibited for the entire period they were on the foliage. Even aphids that were placed on treated foliage 8 days after the application was made did not feed. The percentage of aphids feeding on Fulfill-treated foliage increased with time on foliage, but considering the high mortality on treated foliage (Table 6, Figure 4) very few aphids actually fed. All and all, Fulfill had good efficacy on aphids, including mortality and feeding inhibition. It had residual effectiveness of at least 10 days. Further studies using techniques to reduce control mortality (which were learned in the previous study) would further clarify the efficacy and residual activity of Fulfill (pymetrozine). Table 6. Cumulative percent mortality of aphids placed on Fulfill-treated and untreated potato foliage. Aphids were placed on foliage 0 to 8 days after foliage was treated. 0 Days after treatment when aphids were placed on foliage 1 2 7 8 Days on Foliage 0.0% Fulfill Untr Fulfill Untr Fulfill Untr 1.8% 0.0% 0.0% 8.0% 4.9% 4.2% NE 2.2% 2.1% 19.1% 7.4%* NE 27.9% 13.0% NE NE 88.5% 48.7%* 90.4% 45.7%* 94.7% 48.9%* 90.3% 59.4%* 95.2% 68.1%* 100.0% 67.9%* 1 2 3 4 5 6 7 8 Untr =untreated NE= mortality not evaluated * Percent mortality is significantly different between Fulfill and untreated foliage (P<0.05). Fulfill Untr Fulfill Untr 2.4% 8.1% 0.0%* 22.2% 2.5%* 24.4% 13.0%* 59.3% 3.8%* NE NE NE NE NE NE 82.3% 69.4% NE NE Table 7. Percent of live aphids placed on Fulfill-treated and untreated potato foliage that were feeding (stylet inserted into plant tissue). Aphids were placed on foliage 0 to 8 days after pymetrozine application was made. 0 Days after treatment when aphids were placed on foliage 1 2 7 8 Days on Foliage 1 2 3 4 5 6 7 8 Untr =untreated NE= mortality not evaluated Fulfill Untr Fulfill Untr Fulfill Untr Fulfill Untr 0.0% 61.5%* 0.0% 96.6%* 0.0% 96.3%* 0.0% 83.3%* 4.4% 83.8%* 7.1% 87.0%* 13.8% 81.9%* 54.5% 98.0%* 45.5% 73.1% 48.4% 77.5%* Fulfill Untr 0.0% 0.0% 70.0%* 60.0% 96.0%* 0.0% 62.5% 16.7% 41.5% 0.0% 66.7% none 82.4% alive 100% s d i h p A f o y t i l a t r o M t n e c r e P e v i t a l u m u C 80% 60% 40% 20% 0% 0 Number of Days after Treatment Aphids were Placed on Foliage one seven zero five two eight 1 2 3 4 5 6 7 8 Days on Foliage Figure 4. Mortality of aphids compared to days left on treated foliage. Different symbols represent different delays after treatment before aphids were placed on the foliage. Funding: Federal Grant and GREEEN Nitrogen and Spacing as Factors in Production of Advanced Breeding Lines (Tablestock and Chip Processing) From Michigan State University Chris M. Long, Dr. Sieg S. Snapp, Dr. D. S. Douches, and Dr. R. W. Chase. Department of Crop and Soil Sciences, Michigan State University, East Lansing, Michigan, USA 48824 Introduction A profile of plant response to nitrogen (N) management and spacing is crucial information for the rapid assessment and uptake of new varieties by the potato industry. The objectives of this study were to investigate the response of promising new lines to plant population density (narrow and wide within-row spacing, from 8 to 15 inches and fertilizer levels from 180 to 360 lb/ A. The response of four new lines from the Michigan State University potato breeding program were compared to the chip-processor Snowden over a two year period (2001-2002 growing seasons). Materials and Methods Nitrogen and spacing profiles were developed for the following varieties: Liberator, (MSA091-1, Chip Processor) Snowden (Check, Chip Processor) MSG227-2 (Chip Processor) Jacqueline Lee (MSG274-3, Tablestock) MSE192-8Rus (Tablestock) Liberator (MSA091-1), a 50 ºF storage chipper with tolerance to common scab (Streptomyces scabies Thaxter), MSG227-2, a cold storage (45 ºF) chipper with common scab tolerance, MSE192-8Rus, a russet tablestock line with excellent internal quality and MSG274-3, a European type tablestock line tolerant to the US 8 genotype of Phytophthora infestans. A randomized split-split design trial was conducted at the Montcalm Research Farm in Central Michigan on a Alfic Fragiorthod loamy sand soil during the summers of 2001 and 2002. Treatments are listed below in Table 1. Table 1. Treatment List. NARROW SPACING WIDE SPACING LINE Liberator MSG227-2 Snowden MSE192-8Rus Jacqueline Lee N LEVEL lb/A 180, 270, 360 180, 270, 360 180, 270, 360 180, 270, 360 180, 270, 360 Inches 8” 8” 8” 8” 10” Inches 13” 13” 13” 13” 15” Results Leaf canopy cover was measured in two ways: vigor score and light transmission through canopy, correlated with leaf area index (LAI). Both methods indicated that wider spacing reduced vigor and canopy closure. Overall, Liberator had the most vigorous vine (Table 2.). As shown in Tables 2, 4, 6, and 7, respectively the narrow (8”) spacing and 180 lb. N/A level produced the highest US#1 yield levels which are as follows: Liberator 374 cwt/A, MSG227-2 450 cwt/A, Snowden 391 cwt/A and Michigan Purple 379 cwt/A. Table 3 and 5 show MSE192- 8Rus and Jacqueline Lee obtaining their highest US#1 yields at 270 lb. N/A. Compared to wide spacing, narrow spacing consistently increased yields of the chip processing lines by approximately 10 to 25% (Tables 2, 4 and 6). Nitrogen level had the greatest influence on yield for the tablestock lines. During the 2001 season, petiole nitrate status reflected nitrogen responses of the two tablestock lines, where an increase in yield and higher petiole nitrate was observed when comparing 180 N to 270 N levels. However, in 2002 “luxury” uptake of nitrogen occurred as shown by the petiole nitrate levels associated with the 360 N treatment, which was not reflected in a yield increase (Figures 1-11). Conclusions • There appears to be a trade-off between plant population density and nitrogen fertility management for these varieties, where a narrow row spacing (higher plant population density) provides maximum yield potential at lower and recommended nitrogen levels (180 lb N/A). This optimizes N efficiency. • Petiole N level late in the growing season indicates plant nitrogen status. This indicates that petiole nitrate monitoring is a useful indicator of efficiencies of nitrogen management strategies, but not necessarily an early indicator which can be used to help mid-season nitrogen fertility decisions. • The highest yield levels for Snowden, Liberator and MSG227-2 were recorded at the 180 N level and high planting density (8” spacing). • Jacqueline Lee and MSE192-8Rus exhibited a yield increase when the nitrogen level was increased from 180 to 270 lb N/A. No yield increase was observed when the level was increased to 360 lb N/A. • No response was observed for any variety when the nitrogen level was increased to 360 lb N/A and is not recommended in any fertility, production program. • The three chipping varieties are stored in the Cargill Demonstration storage and will be evaluated for storage quality over the 2002-2003 storage season with the results being reported at a later date. • An additional trade-off exists between nitrogen level, plant population and tuber size distribution which is evident in the Snowden variety. The highest yield for this variety was reported at low N and 8” spacing, but the optimum size distribution occurs at low nitrogen and wide spacing. Commercial producers have chosen a reduction in yield to gain a larger percent of production in the US#1 size category. TABLE 2. LINE LIBERATOR LIBERATOR LIBERATOR LIBERATOR LIBERATOR LIBERATOR TABLE 3. LINE MSE192-8Rus MSE192-8Rus MSE192-8Rus MSE192-8Rus MSE192-8Rus MSE192-8Rus TABLE 4. LINE MSG227-2 MSG227-2 MSG227-2 MSG227-2 MSG227-2 MSG227-2 Yield and Quality Performance of Avanced Breeding Lines and Snowden Control in a Nitrogen Management Profile at the Montcalm Research Farm Averaged Over 2001 and 2002. Nitrogen Level in Pounds Per Acre; In-furrow Spacing, Narrow (8" OR 10") and Wide (13" OR 15") NITROGEN LEVEL 180 270 360 180 270 360 LSD0.05 US#1 YIELD SPACING (CWT/A) NARROW 374 NARROW 361 NARROW 343 309 331 307 41 WIDE WIDE WIDE NITROGEN LEVEL 180 270 360 180 270 360 LSD0.05 US#1 YIELD SPACING (CWT/A) NARROW 247 NARROW 258 NARROW 202 230 257 234 40 WIDE WIDE WIDE NITROGEN LEVEL 180 270 360 180 270 360 LSD0.05 US#1 YIELD SPACING (CWT/A) NARROW 450 NARROW 436 NARROW 378 369 378 352 56 WIDE WIDE WIDE PERCENT OF TOTAL YIELD PERCENT* "B" SPECIFIC INTERNAL SIZE PICKOUTS OVERSIZE GRAVITY DEFECTS 8.6 8.2 10.0 7.9 6.8 7.8 9.2 9.3 9.4 12.5 14.6 15.6 2.7 3.7 5.1 4.3 5.9 5.9 30 25 24 24 29 16 1.076 1.075 1.073 1.074 1.074 1.073 0.002 PERCENT OF TOTAL YIELD PERCENT* "B" SPECIFIC INTERNAL SIZE PICKOUTS OVERSIZE GRAVITY DEFECTS 31.1 28.2 35.2 24.1 20.6 22.3 3.7 5.4 5.2 10.2 10.9 9.9 2.6 3.5 6.6 5.4 6.5 10.6 5 5 5 0 3 6 1.063 1.062 1.061 1.062 1.063 1.061 0.001 PERCENT OF TOTAL YIELD PERCENT* "B" SPECIFIC INTERNAL SIZE PICKOUTS OVERSIZE GRAVITY DEFECTS 8.5 8.2 10.8 5.7 4.9 6.8 6.8 3.9 6.0 13.3 10.2 8.0 3.7 3.8 8.0 6.2 10.8 10.5 15 3 10 15 8 5 1.071 1.072 1.070 1.071 1.070 1.070 0.002 NUMBER OF TUBERS PER PLANT "B" "A" SIZE PICKOUTS OVERSIZE SIZE 1.51 4.68 4.69 1.45 4.89 1.75 5.86 2.02 6.16 1.74 1.90 5.26 0.91 0.43 0.20 0.23 0.23 0.40 0.52 0.50 0.17 0.16 0.18 0.25 0.21 0.29 0.35 0.13 VIGOR** US#1 RATING LAI*** 4.87 3.15 3.25 4.92 3.05 5.11 2.25 6.25 2.98 6.68 5.77 2.95 1.07 0.88 5.00 4.75 5.00 4.25 5.00 5.00 0.48 NUMBER OF TUBERS PER PLANT "B" "A" SIZE PICKOUTS OVERSIZE SIZE 3.51 4.03 3.72 3.56 2.96 4.21 4.29 4.91 5.23 4.04 4.61 4.30 0.88 0.86 0.09 0.13 0.12 0.34 0.41 0.32 0.14 0.12 0.16 0.23 0.31 0.36 0.65 0.22 VIGOR** US#1 RATING LAI*** 2.10 3.60 2.88 3.85 3.20 3.08 5.25 1.30 2.18 5.64 2.60 4.93 0.86 0.39 4.00 4.00 3.75 3.00 3.25 3.25 0.57 NUMBER OF TUBERS PER PLANT "B" "A" SIZE PICKOUTS OVERSIZE SIZE 1.77 6.28 5.93 1.60 5.03 2.07 7.15 1.63 6.49 1.53 2.00 6.93 1.09 0.70 0.22 0.12 0.18 0.54 0.45 0.34 0.22 0.20 0.20 0.43 0.45 0.74 0.81 0.36 VIGOR** US#1 RATING LAI*** 6.50 2.73 2.43 6.05 2.83 5.21 2.35 7.70 2.63 6.94 7.27 2.03 0.85 1.13 3.75 4.00 4.00 2.75 3.25 3.25 0.55 * PERCENT INTERNAL DEFECTS are based on an average across four reps each rep containing ten tubers each. ** VIGOR RATING is a 1 - 5 rating where 5 represents a flower plant canopy and a 1 represents a dead canopy. 2001 Data Only. *** LEAF AREA INDEX is a quantitative measure of leaf canopy. The greater the LAI number the more vigorous the canopy. 2001 Data Only. **** 2002 Data only. BOLD indicates highest yield Yield and Quality Performance of Avanced Breeding Lines and Snowden Control in a Nitrogen Management Profile at the Montcalm Research Farm Averaged Over 2001 and 2002. Nitrogen Level in Pounds Per Acre; In-furrow Spacing, Narrow (8" OR 10") and Wide (13" OR 15") TABLE 5. LINE JACQUELINE LEE JACQUELINE LEE JACQUELINE LEE JACQUELINE LEE JACQUELINE LEE JACQUELINE LEE TABLE 6. LINE SNOWDEN SNOWDEN SNOWDEN SNOWDEN SNOWDEN SNOWDEN TABLE 7.**** LINE MICHIGAN PURPLE MICHIGAN PURPLE NITROGEN LEVEL 180 270 360 180 270 360 LSD0.05 US#1 YIELD SPACING (CWT/A) NARROW 269 NARROW 284 NARROW 243 263 296 256 50 WIDE WIDE WIDE NITROGEN LEVEL 180 270 360 180 270 360 LSD0.05 US#1 YIELD SPACING (CWT/A) NARROW 391 NARROW 352 NARROW 332 343 333 328 46 WIDE WIDE WIDE NITROGEN LEVEL 180 180 LSD0.05 US#1 YIELD SPACING (CWT/A) NARROW 379 353 69 WIDE PERCENT OF TOTAL YIELD PERCENT* "B" SPECIFIC INTERNAL SIZE PICKOUTS OVERSIZE GRAVITY DEFECTS 36.9 33.7 37.9 31.9 28.3 30.2 4.1 4.9 7.4 7.1 5.8 6.6 0.9 1.6 1.2 1.2 2.7 2.2 3 4 1 5 4 4 1.071 1.071 1.071 1.072 1.071 1.071 0.002 PERCENT OF TOTAL YIELD PERCENT* "B" SPECIFIC INTERNAL SIZE PICKOUTS OVERSIZE GRAVITY DEFECTS 15.6 18.0 21.9 11.1 12.0 13.2 2.7 2.1 1.5 3.6 4.5 5.2 0.3 0.9 0.7 1.1 0.9 1.3 23 15 16 19 20 24 1.073 1.073 1.072 1.072 1.072 1.071 0.002 PERCENT OF TOTAL YIELD PERCENT* "B" SPECIFIC INTERNAL SIZE PICKOUTS OVERSIZE GRAVITY DEFECTS 3.7 2.8 9.1 15.9 7.0 8.3 3 5 1.061 1.061 0.004 NUMBER OF TUBERS PER PLANT "B" "A" SIZE PICKOUTS OVERSIZE SIZE 5.95 7.74 5.95 8.27 8.81 5.95 8.52 10.25 8.45 9.02 7.30 7.07 3.12 1.33 0.04 0.11 0.13 0.06 0.16 0.12 0.13 0.34 0.41 0.59 0.69 0.60 0.62 0.38 NUMBER OF TUBERS PER PLANT "B" "A" SIZE PICKOUTS OVERSIZE SIZE 6.42 3.01 6.01 3.42 6.12 3.94 9.10 2.84 8.19 2.92 3.24 7.93 1.11 0.74 0.07 0.07 0.04 0.15 0.16 0.19 0.10 0.03 0.04 0.05 0.07 0.06 0.11 0.08 NUMBER OF TUBERS PER PLANT "B" "A" SIZE PICKOUTS OVERSIZE SIZE 4.84 0.82 5.81 0.82 0.77 0.75 0.26 0.52 0.25 0.18 0.40 0.19 VIGOR** US#1 RATING LAI*** 1.83 5.99 2.53 6.07 6.08 2.68 1.90 8.58 2.38 8.60 1.75 7.41 1.33 1.11 4.50 4.75 4.50 3.75 4.00 3.75 0.76 VIGOR** US#1 RATING LAI*** 2.88 6.49 2.73 6.07 2.63 6.17 1.65 9.25 1.23 8.31 8.12 2.48 1.45 1.11 4.00 4.25 4.00 3.25 3.75 3.50 0.76 US#1 5.10 6.33 0.88 * PERCENT INTERNAL DEFECTS are based on an average across four reps each rep containing ten tubers each. ** VIGOR RATING is a 1 - 5 rating where 5 represents a flower plant canopy and a 1 represents a dead canopy. 2001 Data Only. *** LEAF AREA INDEX is a quantitative measure of leaf canopy. The greater the LAI number the more vigorous the canopy. 2001 Data Only. **** 2002 Data only. BOLD indicates highest yield Figure 1. ) m p p ( n i l e v e L e t a r t i N 2001 Average Petiole Nitrate Levels For Liberator (MSA091-1) 40000 35000 30000 25000 20000 15000 10000 7/6/2001 7/13/2001 7/20/2001 7/27/2001 8/3/2001 8/10/2001 8/17/2001 Sampling Date 2001 Average Petiole Nitrate Levels For MSE192-8Rus Figure 2. ) m p p ( n i l e v e L e t a r t i N 40000 35000 30000 25000 20000 15000 10000 Figure 3. ) m p p ( n i l e v e L e t a r t i N 7/6/2001 7/13/2001 7/20/2001 7/27/2001 8/3/2001 8/10/2001 8/17/2001 Sampling Date 2001 Average Petiole Nitrate Levels For MSG227-2 40000 35000 30000 25000 20000 15000 10000 7/6/2001 7/13/2001 7/20/2001 7/27/2001 8/3/2001 8/10/2001 8/17/2001 Sampling Date 180 N 270 N 360 N 180 N 270 N 360 N 180 N 270 N 360 N 2001 Average Petiole Nitrate Levels For Jacqueline Lee(MSG274-3) Figure 4. 40000 35000 30000 25000 20000 15000 10000 ) m p p ( n i l e v e L e t a r t i N 7/6/2001 7/13/2001 7/20/2001 7/27/2001 8/3/2001 8/10/2001 8/17/2001 Sampling Date 2001 Average Petiole Nitrate Levels For Snowden Figure 5. 40000 35000 30000 25000 20000 15000 10000 ) m p p ( n i l e v e L e t a r t i N 7/6/2001 7/13/2001 7/20/2001 7/27/2001 8/3/2001 8/10/2001 8/17/2001 Sampling Date 180 N 270 N 360 N 180 N 270 N 360 N Figure 6. ) m p p ( n i l e v e L e t a r t i l N e o i t e P 2002 Average Petiole Nitrate Levels For Liberator (MSA091-1) 30000 25000 20000 15000 10000 5000 7/3/2002 7/17/2002 7/31/2002 8/15/2002 Sampling Date 2002 Average Petiole Nitrate Levels For MSE192-8Rus Figure 7. 30000 25000 ) m p p ( n 20000 i l e v e L e t a r t i N e l o i t e P 15000 10000 5000 7/3/2002 7/17/2002 7/31/2002 8/15/2002 Sampling Date 2002 Average Petiole Nitrate Levels For MSG227-2 Figure 8. 30000 25000 ) m p p ( n 20000 i l e v e L e t a r t i N e l o i t e P 15000 10000 5000 7/3/2002 7/17/2002 7/31/2002 8/15/2002 Sampling Date 180 N 270 N 360 N 180 N 270 N 360 N 180 N 270 N 360 N 2002 Average Petiole Nitrate Levels For Jacqueline Lee (MSG274-3) Figure 9. 30000 25000 ) m p p ( n 20000 i l e v e L e t a r t i N e l o i t e P 15000 10000 5000 7/3/2002 7/17/2002 7/31/2002 8/15/2002 Sampling Date 2002 Average Petiole Nitrate Levels For Snowden Figure 10. 30000 25000 ) m p p ( n 20000 i l e v e L e t a r t i l N e o i t e P 15000 10000 5000 7/3/2002 7/17/2002 7/31/2002 8/15/2002 Sampling Date 2002 Average Petiole Nitrate Levels For Michigan Purple Figure 11. 30000 25000 ) m p p ( n 20000 i l e v e L e t a r t i N e l o i t e P 15000 10000 5000 7/3/2002 7/17/2002 7/31/2002 8/15/2002 Sampling Date 180 N 270 N 360 N 180 N 270 N 360 N 180 N Funding: GREEEN, IFAFS Improving Productivity and Soil Quality in Short Potato Rotations 2002 Research Report Sieg Snapp, Judith Nyiraneza and Kitty O’Neil Departments of Horticulture and Crop and Soil Science Michigan State University, East Lansing, MI 48824 Summary A 6-year study of short potato rotations and cover crops was implemented in 2001 at 2 locations in Michigan, at the Montcalm Research Farm near Entrican, and at the Southwest Michigan Research Extension Center near Benton Harbor. Potatoes are rotated with snap beans, corn or wheat with or without one of 3 different cover crops. Some rotations are also split for a composted poultry manure comparison. Objectives of the experiment are to monitor yield and quality of crops harvested and to monitor improvements in soil quality over time. This report presents findings from the 2002 growing season at the Montcalm Research Farm location. Potato and snap bean yields were increased with the application of 2.5 T/acre composted poultry manure. Compost application did not affect incidence of common scab on potato tubers. Rye or rye + hairy vetch cover crop increased potato and snap bean yield compared with a bare winter fallow (no cover crop). Introduction Potato production in Michigan has become more intensive as urbanization and land values have increased in potato producing areas. This has led to increased use of short two-year rotations, alternating potatoes with corn, wheat, beans or other vegetables. Depletion of organic matter in these rotations is a problem, particularly on well-drained sandy soils. Growers widely use winter cereals as cover crops in Michigan to protect soil from wind erosion, and to help maintain soil organic matter (SOM). Maintenance of SOM is critical for successful long-term production. Depletion of SOM results in reduction of soil water holding capacity. Researchers have estimated that for each 0.5% loss of organic matter, water holding capacity is reduced by 10%. Loss of SOM also results in a reduction in nutrient availability and nutrient buffering capacity which increases fertilization requirements. Soil structure, texture and tilth are damaged with loss of SOM and more problems with soil crusting and poor drainage occur. Increased requirements for fumigation have also been associated with losses of SOM. Growers must actively manage for maintenance and improvement of SOM to compensate for intensive tillage and minimal residues associated with potato rotations. Effective methods for improving soil organic matter are regular application of livestock manure or compost, use of cover crops between principle crops, use of green manure crops, and maximizing return of crop residues. Rotating potatoes with reduced tillage crops such as winter wheat or no-till soybeans will also help maintain SOM. Methods Field Experiments: A 6-year trial was initiated in 2001 at the Montcalm Research Farm in Entrican and at the Southwest Michigan Research and Extension Center (SWMREC) near Benton Harbor. Both sites have well-drained, loamy sand to sandy loam soils that are common soil types used to produce a wide range of vegetable crops. At the Montcalm Research Farm the soil is a Montcalm/McBride loamy sand and at SWMREC the soil is an Oakville series fine sand transition to loamy sand (Table 1.). The two sites provide information about performance under a conventional potato production environment at a southern Michigan location with a warmer spring, and a cooler central Michigan location. Table 1. Soil texture and chemical properties for 0-8” depth at the Montcalm Research Farm plot Organic C, % Texture, % sand Calcium, ppm Average Range Average Range Average Range 0.4 – 3.6 1.5 78 63 - 89 388 200 - 1000 The trial includes seven 2-year potato rotations and one 3-year rotation system with 3 cover crop options (see Table 2). Table 2. Rotation, cover crop and compost treatments used in long-term potato rotation experiment at Montcalm Research Farm and SWMREC Cover Crop Rotation Manure 2Y 2Y 2Y 2Y 2Y 2Y 2Y 3Y + or - compost + or - compost + or - compost Bare (no cover crop) Potato / Snap Bean Rye Potato / Snap Bean Rye + Hairy Vetch Potato / Snap Bean Rye after Potatoes, Bare after Corn Potato / Corn Rye + Hairy Vetch Potato / Corn Wheat after Potatoes, Rye after Wheat Potato / Wheat Potato / Wheat Wheat / Red Clover (frost seeded) Potato / Corn / Wheat Rye+Hairy Vetch or Wheat+Clover 1. 2. 3. 4. 5. 6. 7. 8. Rotation treatment 1 represents a worst-case system where soil is left bare after potato harvest. Treatment 8 is included as a best-case option with a 3 year rotation using less tillage and cereal+legume cover crops. Rotation treatments 2 and 4 represent commonly used rotations and winter cover crops for Michigan potato growers. Three snap bean rotation treatments were split for a composted poultry manure treatment comparison. Dry poultry manure compost was applied to split plots at 2.5 T / acre in the spring before planting. Principle crops and cover crops were planted with standard commercial equipment. Varieties and hybrids used are listed in Table 3. Fertilizer was applied to potato plots at the recommended rate of 180 lb N/acre. Plots were irrigated as needed. Cover crops were planted after principle crops were harvested in the fall except for red clover which was frost-seeded into wheat in the spring. Standard pest and weed control measures were used. Table 3. Varieties of principle and cover crops used in long-term potato rotation experiment at Montcalm Research Farm and SWMREC Crop Potato Snap Bean Sweet Corn Wheat Rye Hairy Vetch Red Clover Variety or Hybrid Snowden HiStyle Jackpot Caledonia Wheeler Common Mammoth This report focuses on the 3 snap bean rotation treatments (numbered 1 through 3 in Table 1) at the Montcalm Research Farm location for the 2002 growing season. Potatoes were harvested on 26 September 2002. Tubers were graded manually into size and cull categories and weighed. Snap beans were harvested on 26 August 2002. Row sections were harvested and were manually separated into bean pods and stems and weighed. Results and Discussion Application of composted poultry manure increased yield in both potatoes and snap beans. Rye and rye + hairy vetch cover crops also increased yields of potatoes and snap beans over no cover crop (see Figures 1 and 2). The combination of cover crop and compost application had an additive effect for potatoes, resulting in the highest yields of US No. 1 tubers (Figure 1). Scab was unaffected by compost application in this experiment (Figure 3), but in a related container experiment, poultry manure compost did increase incidence of common scab (Nyiraneza and Snapp, unpublished data). In a related experiment, we found that the rye cover crop released nitrogen very late in the growing season, while the combination of rye cover crop and poultry manure constantly released nitrogen at an optimal time for potato production (Figure 4). Effects of cover crop and composted poultry manure on soil quality parameters are being examined. Detectable improvements are expected to take 2 or 3 years. Table 3. Yields of US No. 1 potato tubers and fresh bean pods in long-term potato rotation experiment at Montcalm Research Farm and SWMREC Bare (no cover crop) Cereal (rye or wheat) Rye + Hairy Vetch Wheat + Clover Potato Yield US No. 1 cwt/A 230 243 273 251 N 23 23 24 11 SE 15 15 16 18 Snap Bean Yield Fresh lb./A 6760 11845 11476 N 16 16 16 SE 1632 716 950 ) A / t w c ( l i d e Y 1 . o N S U + Compost - Compost 500 400 300 200 100 0 Bare Rye Rye + Vetch Cover Crop Treatment Figure 1. US No. 1 tuber yield (cwt/acre) by cover crop and compost treatment ) A / . l i b l ( d e Y n a e B h s e r F - Compost + Compost 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 Bare Rye Rye + Vetch Cover Crop Treatment Figure 2. Fresh snap bean yield (lb./acre) by cover crop and compost treatment ) 4 o t 0 ( g n i t a R b a c S - Compost + Compost 1.0 0.8 0.6 0.4 0.2 0.0 Rye Rye + Vetch Bare Cover Crop Treatment Figure 3. Scab Rating (0 to 4) of tubers by cover crop and compost application / 2 m c m p p N - e t a r t i N 30 25 20 15 10 5 0 y a M - 4 2 Bare Rye Compost Compost+Rye n u J - 3 n u J - 3 1 n u J - 3 2 l u J - 3 l u J - 3 1 l u J - 3 2 g u A - 2 Figure 4. Nitrogen mineralization curve for cover crops and composted poultry manure. (Nyiraneza and Snapp, unpublished data) Additional Resources Additional information regarding manure and compost application is available online from the Michigan Manure Resources Network (web2.msue.msu.edu/manure) and from the Michigan Agriculture Environmental Assurance Program (www.maeap.org). Cover crop information is available from the Kellogg Biological Station Cover Crops program (www.kbs.msu.edu/Extension/Covercrops/home.htm) and from the Sustainable Agriculture Network (www.sare.org/htdocs/pubs/mccp) Calcium Nutrition for Improved Quality and Storage of Potatoes 2002 Research Report Funding: MPIC Sieg Snapp, Chris Long and Deirdre Holcroft Departments of Horticulture and Crop and Soil Science Michigan State University, East Lansing, MI 48824 Summary Improvements in potato yield, quality and storability remain primary objectives for Michigan potato growers and researchers. Experiments were designed and implemented in 2002 to monitor yield, quality and storability responses of Pike and 1879 varieties with differing nitrogen and calcium fertilization management. No significant treatment effects were observed in the 1879 experiment. In the Pike experiment, no significant nitrogen treatment effects were observed, however calcium treatments resulted in several significant effects. Poultry manure compost improved yield of total, US No. 1, A and B size tubers and increased specific gravity compared with the untreated control. Compost and CaNO3 applied once did not reduce tuber defects, but gypsum and split-applied CaNO3 reduced internal brown spot and total tuber defects. Compost increased scab rating of Pike tubers. Storage effects of calcium and nitrogen treatments will be monitored for both varieties through winter months. Introduction National potato markets have become increasingly competitive for Michigan potato growers. As chip and tablestock potato buyers continue to raise minimum acceptable quality standards, Michigan potato growers must respond by continuing to improve the quality of their produce to meet and exceed these higher acceptability standards. Growers can gain competitive advantage if they can achieve and maintain outstanding potato quality and if they are able to store high quality tubers longer into the spring months. Proper management of nitrogen (N) and calcium (Ca) nutrition in the field can directly affect these fundamental goals. For optimal yield and quality, these 2 nutrients must be available in adequate levels at the critical stages of plant growth and tuber development. The ‘Pike’ variety has commonly been susceptible to internal necrosis, internal brown spot or brown center tuber defects. Calcium fertilization has been shown to be a critical element for optimal tuber development, resistance to post-harvest soft rots and for improved storage reconditioning. (Chase et al, 1990; Erribhi et al, 1998; Palta, 1996). Results of trials have not been uniformly conclusive, however. Methods Two field experiments were conducted on sandy loam soil at the Montcalm Research Farm, Entrican, MI. Soil properties are listed in Table 1. Four-row plots were applied with fertilizer treatments before planting and split N and Ca applications were applied at hilling and at blossom stage as specified by treatment design. Plots were planted on 1 May and harvested 155 days later on 3 October, 2002. Table 1. Soil profile organic carbon, texture and chemical characteristics of trial site for calcium nutrition study, Montcalm Research Farm, 2002. Topsoil (0-8 in) Subsoil (8-20 in) Deep subsoil (20-32in) Silt Clay Organic C - - - - - - - - - - % - - - - - - - - - - Sand 0.62 0.22 0.23 78 77 63 13 12 16 9 11 1 pH P Mg - - - - - - - - lb/acre - - - - - - - - Ca K 6.25 313 6.95 80 228 145 690 850 246 290 6.88 33 163 1480 322 Experiment 1 was designed to compare N and Ca nutrient sources for ‘Pike’ variety potatoes. Each Ca treatment provided 200 lb. Ca: 1. Calcium nitrate (CaNO3) in a single pre-plant application, 2. CaNO3 in a split application (1/3 pre-plant, 1/3 at hilling, and 1/3 at blossom stage), 3. Poultry manure compost (10% Ca) applied pre-plant at 2.5 tons / acre, 4. Gypsum applied in a single pre-plant application, and 5. Untreated control receiving no Ca fertilization. Each Ca treatment was combined with N fertilizer for a total of 180 or 360 lb. N/acre Nitrogen credits were given for the CaNO3 and the poultry manure compost. Experiment 2 was designed to Ca sources for Frito Lay ‘1879’ variety potatoes. Calcium treatments were: 1. CaNO3 to provide 200 lb. / A in a single pre-plant application, 2. CaNO3 to provide 200 lb. / A in a split application (1/3 pre-plant, 1/3 at hilling, and 1/3 at blossom stage), 3. Poultry manure compost (10% Ca) to provide 200 lb./A applied pre-plant at 2.5 tons / A, 4. Gypsum at 200 lb. Ca / A applied in a single pre-plant application, 5. Gypsum at 400 lb. Ca / A applied in a single pre-plant application, and 6. Untreated control receiving no Ca fertilization. Nitrogen fertilization was 200 lb. /A for all treatments with credits given for the CaNO3 and poultry manure compost. A 40 lb. credit was used for poultry manure compost assuming 30% release of N through mineralization. Tubers were harvested and graded into A size, B size, oversize and grade-out categories. A subsample of tubers were inspected for internal defects and several samples were designated for laboratory analyses and for long-term storage in the Cargill Demonstration Storage building. Results and Discussion Experiment 1. Nitrogen treatment had no significant effects on yield or quality of Pike tubers. Calcium treatments did not affect tuber Ca concentrations significantly (Figure 1). Calcium concentrations averaged 0.035% across treatments, lower than 2001 levels. Average yield for all treatments in the Pike experiment was 301 cwt/acre. Average yield of US No. 1 tubers was 276 cwt/A. Yield of total, US No. 1, A size, B size and oversize tubers was significantly affected by Ca treatment (Figure 2). Poultry manure compost improved yield of total, US No. 1, A and B size tubers and increased specific gravity compared with control (Figures 3 and 4). Poultry manure compost and a single application of 200 lb. CaNO3 did not reduce tuber defects. Gypsum and split-applied CaNO3 reduced internal brown spot and total tuber defects (p<.15) (Figure 5). Compost increased scab rating (p<.06) (Figure 6). Storage effects will be monitored through winter months Experiment 2. Calcium treatments had no significant effects on yield or quality of 1879 tubers (Figures 7 and 8). Storage effects will be monitored through winter months Conclusions The effects of poultry manure compost on yields and quality look promising. Yield was increased by 50 cwt / acre compared to control for 4 out of 5 trials using compost. Other calcium treatments did not increase yields or improve tuber quality. Calcium content of tubers was not affected though this is often difficult to achieve especially during a dry season such as 2002. Questions remain about the mode of action of poultry manure compost. It is unclear at this point whether poultry compost effects are due to Ca, as a slow-release N source or as a more physical soil quality effect. Similar effects have been observed in other experiments by our lab. We are continuing to monitor quality in the demonstration storage and will report later on these results. References Chase, R., G.H. Silva, and R.B. Kitchen. 1990. Nitrogen and spacing effects on tuber yield and quality of Russet Norkotah and Spartan Pearl. Am Potato J. 67:542-545 Errebhi, M. C.J. Rosen, S.C. Gupta and D.E. Birong. 1998. Potato yield response and nitrate leaching as influenced by nitrogen management. Agron. J. 90:10-15. Palta, J.P. 1996. Role of calcium in plant responses to stresses: Linking basic research to the solution of practical problems. HortScience 31:51-57. 0.05 0.04 0.03 0.02 0.01 0.00 CaNO3 1X CaNO3 Split Compost Control Gypsum ) % ( i m u c a C l r e b u T Figure 1. Pike experiment. Tuber Ca concentrations (%) for different Ca treatments. Each Ca treatment provided 200 lb./A Ca except control which received 0 Ca. 1.074 y t i v a r G c i f i c e p S 1.072 1.070 1.068 1.066 A B B B C CaNO3 1X CaNO3 Split Compost Control Gypsum A / t ) w c ( d e Y i l ) A / t w c ( d e Y l i Total Yield US No. 1 Yield A B B B B 400 300 200 100 0 CaNO3 1X CaNO3 Split Compost Control Gypsum Figure 2 Pike experiment. Yield of total and US No. 1 tubers for different Ca treatments. Each Ca treatment provided 200 lb./A Ca except control which received 0 Ca. ABC=different letters indicate significant difference (P<.01) 350 300 250 200 25 0 A size tubers B size tubers Oversize tubers A B B B B CaNO3 1X CaNO3 Split Compost Control Gypsum Figure 3. Pike experiment. Tuber specific gravity for different Ca treatments. Each Ca treatment provided 200 lb./A Ca except control which received 0 Ca. ABC=different letters indicate significant difference (P<.01) Figure 4. Pike experiment. Yield of A size, B size and oversize tubers for different Ca treatments. Each Ca treatment provided 200 lb./A Ca except control which received 0 Ca. ABC=different letters indicate significant difference (P<.01) 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 Internal Brown Spot Total Tuber Defects A AB a AB ab ab B b B b s t c e e D f r e b u T Control Gypsum CaNO3 1X CaNO3 Split Compost Figure 5. Pike experiment. Frequency of total tuber defects and internal brown spot for different Ca treatments. Each Ca treatment provided 200 lb./A Ca except control which received 0 Ca. ABC, abc=different letters indicate significant difference (P<.15) ) 4 o t 0 ( g n i t a R b a c S 1.0 0.8 0.6 0.4 0.2 A AB AB B B CaNO3 1X CaNO3 Split Compost 0.0 Figure 6. Pike experiment. Tuber scab rating for different Ca treatments. Each Ca treatment provided 200 lb./A Ca except control which received 0 Ca. ABC=different letters indicate significant difference (P<.06) Gypsum Control ) A / t w c ( d e Y l i r e b u T 400 300 200 100 0 Total Yield US No. 1 Yield Total Tuber Defects Hollow Heart Defect Internal Brown Spot ) y c n e u q e r f ( s t c e e D f r e b u T 0.4 0.3 0.2 0.1 0.0 CaNO3 1X CaNO3 Split Compost Control Gypsum 200Gypsum 400 CaNO3 1X CaNO3 Split Compost Control Gypsum 200Gypsum 400 Figure 7. 1879 experiment. Yield of total and US No. 1 tubers for different Ca treatments. Yields were not different for different treatments. Figure 8. 1879 experiment. Frequency of total tuber defects, hollow heart and internal brown spot for different Ca treatments. Defect frequencies were not different for different treatments. Funding MPIC Tolerance of Mycelium of Different Genotypes of Phytophthora Infestans (Mont.) De Bary to Exposure to Temperature below 0oC for Extended Durations. William W. Kirk Department of Plant Pathology, Michigan State University, East Lansing, 48824. INTRODUCTION Late blight of potato, caused by Phytophthora infestans (Mont.) de Bary, is a devastating disease that affects all potato growing regions in the world and has become a major factor adversely affecting potato production in the Northern United States (9). The source of annual epidemics of late blight of potato caused by P. infestans has lead to debate as to the relative importance of over wintering sources of inoculum (23). Late blight over winters in potato tubers that are intended for replanting as seed (5,11,16,27), but the infection may also be harbored in waste or cull potato tubers (3,29) or within late blight infected volunteer potatoes returned to the soil during harvest the previous season, although it is generally agreed this source is of minor importance (8,29). In North America, the probability that infected potato stems or foliage will emerge from an infected tuber is difficult to estimate as several factors can influence the fate of the infected tuber (20,24), temperature being one of the most important (18). The survival of viable host tissue from infection through dormancy to re-emergence the following spring is vital for survival of P. infestans (29). Many investigators have used in vitro and soil assays to study the optimal and lethal upper temperatures for growth of Phytophthora spp. (2,4,15,28). The survival of P. nicotianae chlamydospores in soil was reduced considerably when temperatures were raised above 45oC (4). No studies have been found that examine the ability for P. infestans mycelium to survive at temperatures below zero. P. infestans can survive within infected tubers at 3oC as stored seed (18), however the fate of mycelium of P. infestans within potato tubers exposed to temperatures below 0oC has not been monitored. The objectives of this study were to investigate the ability of different genotypes of P. infestans to survive in vitro at temperatures below 0oC and to determine the duration of exposure at a range of temperatures below 0oC that was lethal to mycelium. MATERIALS AND METHODS Isolate descriptions. Isolates of four genotypes of P. infestans were obtained from foliage of potatoes with symptoms of late blight. The genotypes were determined by isozyme analysis (10), mefenoxam sensitivity (6) and mating type and were obtained from Kirk, MI (US1, mefenoxam sensitive, A1 mating type, MI95-6), Kirk, MI (US8, mefenoxam insensitive, A2 mating type, MI95-7, ATCC MYA-1769), Gudmestad, ND (US11, mefenoxam insensitive, A1 mating type, ND207-4) and Kirk, MI (US14, mefenoxam insensitive, A2 mating type, MI96-1). The isolates were maintained on sterile rye seed stock cultures and re-propagated from the long-term storage stock for each experiment on rye agar. Substrate optimization. Prior to the experiment, several calibrations were performed. Determination of the optimal volume of clarified rye agar added to the 60 mm petri dishes that could be used to optimize the reflectance characteristics for the digital image analysis procedure (described below) was conducted. Clarified rye agar was prepared by Funding MPIC washing 100g organically produced rye seed which was boiled for 1 h in dH2O, strained through cheese cloth to which was added 15g agar, 7.5g sucrose and dH2O to bring the solution to 1L final volume. Volumes of 5, 10, 15 and 20 ml rye agar were pored into Petri dishes (60 mm diameter) and the reflectance intensity determined by digital image analysis. The scanned images were the rye petri plates without cover lids. The petri plates were placed open-surface down on a glass plate, 40 x 30 cm and 2 mm thick. The glass plate was used to prevent surface contamination of the scanner glass and permitted multiple samples to be prepared and moved to the scanner for image production. The glass plate was transferred to a flatbed scanner (HP ScanJet 4c, Hewlett-Packard Co., Houston, TX) controlled by an IBM-compatible PC. A 486DX2-80 CPU and a RAM capacity of 32 MB were adequate for the image processing. Scanner control software (DeskScan II ver. 2.4, Hewlett-Packard, Co., Houston, TX) generated an image of the petri plate agar surfaces against a black background. The image was formed from light reflected from the agar surfaces. The brightness value of the image controlled the light intensity of every pixel in the image. The contrast value controlled the differences between light and dark regions of the image. While the scanner control software was able to automatically adjust the brightness and contrast of the image by comparing the relative area of the pale rye agar surfaces against the black background, the settings were manually set to 180 units (brightness) and 200 units (contrast) to ensure consistent readings. A photograph-quality image was taken and stored for analysis. A typical image in Tagged Image Format (*.tif) occupies about 1 megabyte. The image files created with the scanner software were loaded into the image analysis software (SigmaScan Pro ver. 5.0.0 build number 3981, SPSS Science, 233 S. Wacker Drive, 11th floor, Chicago, IL 60606-6307). The black background has 0 light intensity units (LIU), while pure white has 255 LIU. The clarified rye was pale gray. The image of the clarified rye surface was selected for analysis, and isolated from the adjacent regions of the image. The image was unedited. The area was selected with the “fill” tool, which encompassed all pixels within a given area brighter than the cut-off threshold. The area selection cut-off threshold was set to 10 LIU, effectively allowing the software to exclude all parts of the image darker than 10 LIU, e.g. the black background. The average reflective intensity (ARI) of all the pixels within the image gave a measurement of the plate without any growth of the sample. The calibrations resulted in optimal agar volumes of 10 ml substrate/60 mm diameter petri plates with mean ARI = 90. Determination of developmental stage of sporangia on mycelial plugs after transfer from parent cultures. As the objective of the experiment was to determine the influence of duration of exposure of temperatures less than 0oC on mycelial survival, it was necessary to determine the length of time for all sporangia to germinate after transfer of mycelial plugs from parent cultures. P. infestans cultures of each isolate were grown on sterol-free rye agar plates for 14 days in the dark at 12oC. Ten 5 mm diameter cores were removed from the growing edge of each of 10 plates. The cores were placed into 10 ml distilled H2O in test tubes and stirred on a magnetic stirrer for 1 hour to dislodge sporangia. The suspension was strained through four layers of cheesecloth and the concentration of sporangia was calculated using a haemacytometer. The number of non- germinated and germinated sporangia was counted at the time of transfer and again two days after incubation at 4oC. After two days only empty sporangia were observed in any Funding MPIC of the isolates tested and a pre-treatment of two days incubation at 4oC in the dark was imposed on all freshly transferred cores prior to exposure to temperature treatments. Temperature exposure studies. The first set of temperature exposure experiments were conducted over a 24 h period. Fifty plates of each isolate were prepared 48 h prior to introduction to the temperature treatment. The plates were labeled with culture ID numbers and exposure times and bound together with parafilm and placed together on a fitted plastic loading tray transferred to a PTC-1 Peltier-effect temperature cabinet controlled by a PELT-3 Peltier-effect temperature controller (Sable Systems International, 2887 Green Valley Parkway #299, Henderson, NV 89014). The PTC-1 chambers were positioned in temperature-controlled environment chambers, 1.8 m3 volume (Environmental Growth Chambers, Chagrin Falls Ohio, USA) at 5oC. The PELT-3 Peltier-effect temperature controller was set for the exposure temperature 2 h prior to the start of the experiment. The tray with the culture plates was placed into the PTC-1 Peltier-effect temperature cabinet quickly to minimize temperature increase. Temperature equilibration was measured after the door of the chamber was opened, and at 0oC set temperature, temperature rose to 5oC after the door was opened and dropped to -0.3oC in 1.5 hr. At -3, -5, -10 and -20oC set temperatures, temperature rose to -1.2, -1.5, - 3.5 and -4.8oC and recovered in 1.1, 1.3, 1.5 and 1.4 h respectively. Exposure times were measured from when the set temperature was reached. Plates were removed after exposures of 1, 4, 8, 12 and 24 h. Temperature treatments were 0, -3, -5, -10 and -20oC. After plates were removed from the PTC-1 Peltier-effect temperature cabinet they were stored in the light at 12oC. After 14 days a sample (replication 1 of the experiment only) of 5 plates was scanned to determine amount of growth of mycelium. The second set of plates (n = 5) was retained for 28 days prior to evaluation. The lids were removed from the plates and the plates were placed face down and images generated (as described above). The experiment was repeated twice over the period from December 2000 to February 2001. The second and third replications of the experiment were evaluated 28 days after the temperature treatments. The second set of temperature exposure experiments were conducted over a 7 day period. Temperature exposure treatments were selected after analysis of the first experiments (exposure over a 24 h period). The experiment was set up as described above except plates were removed from the PTC-1 Peltier-effect temperature cabinet after exposures of 1, 2, 3, 4 and 5 days. Temperature treatments were 0, -3 and -5oC. The experiment was repeated twice over the period from March to April 2001. Plates were scanned 28 days after removal from the temperature exposure treatment. Data analysis. The relation between the ARI and weight of individual cultures was determined by linear regression (SigmaStat ver. 2.03, Jandel Scientific, San Rafael, CA). Interactions between temperature and duration of exposure were determined by three- way ANOVA for each replication of both experiments (24 h and 120 h maximum exposure) and if the replications were not significantly different at p = 0.05 the data were combined into a single analysis and an LSD generated for comparison of all treatments. To determine if mycelium survived exposure to the thermal treatment, the ARI of treated mycelium were compared to the ARI of a non-inoculated control (negative control) which was added to each exposure treatment using Bonferri analysis (SigmaStat ver. 2.03, Jandel Scientific, San Rafael, CA). Funding MPIC RESULTS Temperature exposure studies. Survival of isolates of different genotypes of P. infestans exposed to temperatures from 0 to -20oC for different durations up to 24 hours measured as ARI (LIU) of images of cultures incubated for 4 weeks after exposure at 12oC is shown in Table 1. All isolates survived exposure to 0 and -3oC for up to 24 h exposure except isolate 207-4 (US 11, A1) which did not survive exposure to -3oC for 12 or 24 h. Exposure to -5oC for up to 24 h was not lethal for the US8 genotype but 24 h exposure was lethal to the US14 genotype which survived exposure up to 12 h. The A1 genotype US1 was not able to survive exposure of greater than 1 h at -5oC but the genotype US11 survived after exposure of up to 8 h. All genotypes except US11 survived 1 h exposure to –10 oC and both A2 genotypes survived exposure to –10 oC up to 4 h. No genotypes survived exposure to -20oC. All isolates of the genotypes of P. infestans survived in vitro exposure up to 120 h at 0 oC (Table 2). Both A1 genotypes survived exposure of up to 48 h at –3oC and the US8 genotype survived exposure to 72 h but the US14 genotype survived after 120 h exposure. A1 genotypes did not survive exposure of 24 h at –5oC but both A2 genotypes showed some potential for recovery up 24 h after exposure to -5oC and US14 sometimes recovered even after 96 h exposure (Table 2). DISCUSSION The digital method of assessment of survival of mycelium of Phytophthora infestans in vitro relies on light reflectance from developing mycelium and therefore an increased average reflective intensity (ARI). Other studies have made use of light reflectance from biological materials that differ in the darkness of the sample e.g. Niemira et al., (1999) compared the differences between a common non-destructive visual rating system with the destructive digital method showed the potential for the use of computerized image generation and analysis for estimation of the amount and rate of tuber tissue infection caused by P. infestans. Image analysis is quantitative and objective and scanned images can be stored for future comparisons. Consistency of sample preparation was an essential element in the scanning method. The relation between the ARI and mycelium weight was direct and established that ARI is a good estimation of survival of the temperature exposed samples. Radial growth of mycelium on plates may overestimate survival potential especially if the mycelium is growing sparsely. In this analysis, only the difference from non-inoculated plates was determined as an indicator of survival potential after exposure of mycelium to a range of temperatures for different durations. Although it is not possible to determine beyond doubt that some sporangia survived the pre-treatments prior to temperature exposure, all steps to ensure minimal production of sporangia in the parent cultures was attempted i.e. incubation in the dark at 12oC on sterol-free growth medium and then acclimatization at 4oC prior to exposure to the temperature treatment. As only empty sporangia were detected after this pre-treatment it was concluded that the plugs exposed to the temperature treatments consisted only of mycelium. No encysted zoospores were observed with the microscopic investigations. The apparent increased tolerance of the two A2 genotypes of P. infestans to lower temperatures is cause for concern. Reports of increased average temperature in the Great Lakes region of the US has resulted in greater potential for survival of volunteer potatoes in fields and culled potatoes (1) which can potentially harbor inoculum of P. infestans. Funding MPIC As the environment in which the mycelium of P. infestans survives (potato tubers) is less frequently exposed to temperatures which normally cause substrate breakdown (about –3oC) the risk of survival of blighted tubers surviving winter also increases. Tolerance to temperature in the range of 0 to -3oC and the continued use of foliar applications of mefenoxam in potatoes for control of tuber disease such as pink rot caused by Phytophthora erythroseptica (25) may have resulted in the predominance of the US8 (A2, mefenoxam resistant) genotype in the Midwestern potato production areas of the US. Different genotypes of P. infestans vary in aggressiveness and virulence in foliar infections (19,21). This study supports the view that the US8 genotype is more virulent than those biotypes isolated prior to 1994 (17) and may partially contribute to a mechanism by which this increased virulence can be explained. As few commercial cultivars have substantive field resistance to foliar infection caused by US8 biotypes of P. infestans (7,12) the potential for survival of mycelium in tubers and production of initial inoculum in succeeding years is ominous for potato production. The estimated base temperature for the development of P. infestans infection of tuber tissue has been reported to be about 3oC when tuber tissue was used as substrate (18). Base temperatures refer to the temperature at which development ceases (22)but are not good indicators of survival potential as mechanisms for tolerance to temperatures below the base temperature for development are known to exist in other fungi(26). Tubers are thought to be at greatest risk from infection by P. infestans, and perhaps other primary and secondary pathogens, immediately after harvest when tuber pulp temperatures are highest. Tuber vulnerability may persist into the first few weeks of storage prior to adjustment of the tuber tissue to the ambient temperature in store (11). A similar mechanism may occur for volunteer tubers left in fields after harvest. Further work on the tolerance of mycelium from a wider range of isolates of P. infestans representative of genotypes not tested in this study and also of genotypes already tested is underway to determine if this tolerance is typical of the genotypes that have largely replaced the clonal lineage (US1) found prior to 1990. Attempts so far to determine survival of mycelium of P. infestans within tubers has failed due to degradation of tuber tissue at -3oC. In addition, as potato growers have commented on the apparent tolerance to ambient temperature in excess of 30oC and recovery potential of lesions after exposure to arid conditions (13,14)the tolerance of mycelium to temperatures in excess of 30oC is also being determined. This material was prepared with the support from the Michigan Potato Industry ACKNOWLEDGMENTS Commission. Funding MPIC Figure 1. Example of images of Phytophthora infestans incubated on plates for 28 days after exposure to different durations of temperature. These are images of Pi95-7 (US8) exposed to -3oC for different durations then incubated at 12oC for 28 days. The values are the average reflective intensities (ARI) in light intensity units (LIU) as measured with Sigma Scan. Plates with no detectable growth of mycelium had ARI values of less than 100 LIU. Note the plate at the bottom left of the figure with minimal growth of mycelium and an ARI > 100. Funding MPIC Bollen, G. J. 1985. Lethal temperatures of soil fungi. In Ecology and Boyd, A. E. W. 1974. Sources of potato late blight (Phytophthora infestans) in the Coelho, L., D. J. Mitchell, and D. O. Chellemi. 2000. Thermal inactivation of 1 Baker, K.M., W.W. Kirk, J.A. Andresen, and J.M.. Stein. 2002. A problem case study: Influence of climatic trends on late blight epidemiology in potatoes. Paper read at Proceedings of the 26th International Horticultural Congress and Exhibition (IHC2002), at Toronto, Ontario, Canada. 2 Management of Soilborne Plant Pathogens, edited by A. D. R. C. A. Parker, K.J. Moore, P. T. W. Wong, and J. F. Kollmorgen. St. Paul, MN: The American Phytopathological Society. 3 east of Scotland. Plant Pathology 23:30 - 36. 4 Phytophthora nicotianae. Phytopathology 90:1089-1097. 5 Davidse, LC, J Henken, A van Dalen, ABK Jespers, and BC Mantel. 1989. Nine years of practical experience with phenylamide resistance in Phytophthora infestans in the Netherlands. Netherlands Journal of Plant Pathology 95 (Suppl. 1):197-213. 6 Deahl, K L, S P DeMuth, S L Sinder, and A Revera-Pena. 1995. Identification of mating types and metalaxyl resistance in North American populations of Phytophthora infestans. American Pot J 72:35-50. 7 Douches, DS, WW Kirk, K Jastrzebski, C Long, and R Hammerschmidt. 1997. Susceptibility of potato varieties and advanced breeding lines (Solanum tuberosum L) to Phytophthora infestans (Mont) de Bary in greenhouse screenings. American Potato Journal 74 (2):75-86. 8 central Washington State. Plant Disease 66:452-455. 9 blight in the United States. Plant Disease 81 (12):1349-1357. 10 electrophoresis for rapid identification of allozyme genotypes of Phytophthora infestans. Plant Disease 79 (11):1181-1185. 11 Sensitive and Metalaxyl-Resistant Isolates of Phytophthora infestans to Whole Potato- Tubers As Affected By Tuber Aging and Storage. Phytoparasitica 23 (2):165-175. 12 Relative resistances of potato clones in response to new and old populations of Phytophthora infestans. Plant Disease 80 (5):575-578. 13 selected late blight fungicides. Plant Disease 84 (10):1116-1120. 14 the Columbia Basin of Washington and Oregon. Plant Disease 82 (6):642-645. 15 E. DeVay. 1991. Thermal sensitivity of three species of Phytophthora and the effect of soil solarization on their survival. Plant Disease 75:1160-1164. Kadish, D, and Y Cohen. 1992. Late blight (Phyophthora infestans (Mont) De 16 Bary) development from potato seed-pieces treated with fungicides. Pesticide Science 55:1151-58. Johnson, Dennis A. 1998. Expansion of potato late blight forecasting models for Goodwin, S. B., R. E. Schneider, and W. E. Fry. 1995. Use of cellulose-acetate Easton, GD. 1982. Late blight of potatoes and prediction of epidemics in arid Fry, W. E., and S. B. Goodwin. 1997. Re-emergence of potato and tomato late Juarez-Palacios, C. , R. Felix-Gastelum, R. J. Wakeman, E. J. Paplomatas, and J. Grinberger, M., D. Kadish, and Y. Cohen. 1995. Infectivity of Metalaxyl- Inglis, D. A., D. A. Johnson, D. E. Legard, W. E. Fry, and P. B. Hamm. 1996. Johnson, D. A., T. F. Cummings, and B. Geary. 2000. Postinfection activity of Funding MPIC Kato, M., E. S. Mizubuti, S. B. Goodwin, and W. E. Fry. 1997. Sensitivity to Kirk, W. W., B.A. Niemira, and J. M. Stein. 2001. Influence of Storage Lambert, D.H., A.I. Currier, and M.O. Olanya. 1998. Transmission of Monteith, J.L. 1977. Climate and the efficiency of crop production in Britain. Partpillo, H.M., M.L. Powelson, and D.A. Inglis. 2000. Seedborne Phytophthora 17 protectant fungicides and pathogenic fitness of clonal lineages of Phytophthora infestans in the United States. Phytopathology 87 (9):973-978. 18 Temperature on Rate of Potato Tuber Tissue Infection Caused by Different Biotypes of Phytophthora infestans (Mont.) de Bary estimated by digital image analysis. Potato Research 44:86 – 96. Lambert, D. H., and A. I. Currier. 1997. Differences in tuber rot development for 19 North American clones of Phytophthora infestans. American Potato Journal 74 (1):39- 43. 20 Phytophthora infestans in cut potato seed. American Journal of Potato Research 75 (6):257-263. Miller, J. S., and D. A. Johnson. 2000. Competitive fitness of Phytophthora 21 infestans isolates under semiarid field conditions. Phytopathology 90 (3):220-227. 22 Philosophical Transactions of the Royal Society of London B281:277 - 297. 23 infestans: Rate of transmission and effect on stand in five potato cultivars. American Journal of Potato Research 77:415. 24 Powelson, M. L., and D. A. Inglis. 1999. Foliar fungicides as protective seed piece treatments for management of late blight of potatoes. Plant Disease 83 (3):265- 268. 25 Secor, G.A., and N.C. Gudmestad. 1999. Managing fungal diseases of potato. Canadian Journal of Plant Pathology-Revue Canadienne De Phytopathologie 21:212- 221. 26 and antifreeze activities in pathogenesis and growth of snow molds. Phytopathology 90:354 - 361. 27 infestans, tevens enige nieuwe bestrijdingsmogelijkheden. Tijdschr. Planteziekten. 62:69- 156. 28 Phytophthora cinnamomi and on growth of its avocado host. Phytopathology 71:925-928. 29 late blight epidemics: Disease foci, disease gradients, and infection sources. Phytopathology 88 (8):754-763. Snider, S.S., T. Hsiang, Zhao. G., and M Griffith. 2000. Role of ice nucleation Zentmyer, G. A. 1981. The effect of temperature on growth and pathogenesis of Zwankhuizen, M. J., F. Govers, and J. C. Zadoks. 1998. Development of potato Van der Zaag, D.E. 1956. Overwintering en epidemiologie van Phytophthora Funding CSREES Sedreal Special Grant Host Plant Resistance and Reduced Rates and Frequencies of Fungicide Application to Control Potato Late Blight (Co-operative trial Quad State Group 2002). W.W. Kirk1, J.B, Muhinyuza1, D.S. Douches2, C. Thill3, J. Jang4 and A. Thompson 5. 1Plant Pathology, 2Crop and Soil Sciences, Michigan State University, 3Crop Science, University of Minnesota, 4University of Wisconsin, 5North Dakota State University. INTRODUCTION Late blight of potato caused by Phytophthora infestans (Mont de Bary), is a major threat to the production of high quality potatoes (12). Unchecked, P. infestans can rapidly defoliate plants in the field and can infect potato tubers when spores are washed into the soil (15). Potato late blight control strategies changed following the migration of mefenoxam/metalaxyl-resistant populations of P. infestans from Mexico to North America (12) and necessitate cultural control methods and crop protection strategies that rely primarily on protectant foliar fungicide applications (12, 18). There are several potential methods for reducing fungicide inputs in potato crop management. These include the use of fungicides with less active ingredient, reduced application rates, longer application intervals and a combination of any of these strategies. In addition, Fry (10, 11) observed that a combination of cultivar resistance and regular applications of protective fungicides reduced foliar late blight infection in potato. There are currently no late blight resistant potato cultivars that meet commercial standards in the United States. However, controlled environment and field trials at Michigan State University have identified certain foreign cultivars and advanced breeding lines (ABL) that are less susceptible to foliar late blight in the absence of fungicides than important cultivars grown and developed in the United States (e.g. Snowden, Atlantic, Russet Burbank) (4, 5, 6, 7). Typical fungicide application programs use a 5-7 day spray interval depending on environmental conditions and grower preference. The frequent fungicide spray intervals and rates currently used by growers to control late blight are expensive and more economical control measures are needed. In April 2001, it was agreed to form an alliance in potato research areas between North Dakota, Minnesota, Wisconsin and Michigan, this has been formally recognized as the Quad State group (now an NCT 190). In 2001, a pilot study was carried out at MSU by Kirk to determine the feasibility of the co-operation. The four breeding programs submitted varieties and a late blight field trial was implemented at the Muck Soils Research Farm, Laingsburg, MI. The results of this co-operation were very positive and have highlighted some of the constraints that growers have on accepting new varieties into their programs. It was agreed to repeat the experiment in 2002. Therefore, the objective of this research was to determine if acceptable control of foliar late blight can be achieved by using increased fungicide spray intervals and reduced application rates of residual contact fungicides on potato germplasm with a range of susceptibility to late blight developed at each of the four potato breeding programs in Michigan, Minnesota, North Dakota and Wisconsin. MATERIALS AND METHODS Potato Germplasm Previous experiments from the co-operating breeding programs have identified potato cultivars and advanced breeding lines (ABL) with different responses to foliar late blight. Jacqueline Lee has consistently been one of the most late blight resistant ABL in five years of testing at Michigan State University and was released in 2001 whereas; Snowden has consistently been one of the most susceptible (5,6,7,8). In the present study, any cultivar/ABL with foliar late blight severity measured as the Relative Area Under the Disease Progress Curve [RAUDPC (1)] value that was not significantly higher than that of Jacqueline Lee was classified as late blight resistant (R). Any cultivar/ABL with a RAUDPC value significantly higher than that of Snowden or with Funding CSREES Sedreal Special Grant a RAUDPC value that was not statistically different from that of Snowden was classified as late blight susceptible (S). Cultivars/ABL were classified as moderately resistant (M) if the RAUDPC value was significantly higher than that of Jacqueline Lee but significantly lower than that of Snowden. The potato cultivars/ABL used to assess the efficacy of reduced fungicide application rate varied among years but always included late blight susceptible controls (e.g. Snowden and Atlantic) and cultivars/ABL classified as moderately resistant or resistant to late blight (5,6,7,8). The susceptible cultivar Snowden and the resistant cultivar Jacqueline Lee was used to assess the efficacy of increased fungicide application intervals in combination with reduced application rates of chlorothalonil against potato late blight. The cultivars/ABL included in the trials from 2002 are listed in Table 1. Residual Contact Fungicides Field experiments to evaluate the efficacy of various fungicide protection strategies against late blight were conducted during 2001. Fluazinam 5SC (non-commercial formulation, ISK Biosciences Corporation, 5966 Heisley Road, PO Box 8000, Mentor, OH 44061-8000) was used. The manufacturer’s recommended application rate (MRAR) was 0.15 ai/ha/application and 1.5 kg ai/ha/season for fluazinam (23). Fungicides were applied with an ATV rear-mounted spray boom (R&D Sprayers, Opelousas, LA, U.S.A.) that traveled at 1 m/s, delivered 230 l H 2O/ha (3.5 kg/cm2 pressure) with three XR11003VS nozzles per row positioned 30 cm apart and 45 cm above the canopy. In the fungicide application interval and reduced dose rates trial, fluazinam 5SC was applied at 5, 10 and 15 day intervals at 0, 50 and 100% MRAR (16) to the ABL and cultivars described in Table 1. The first fungicide application occurred at 27 days after planting (DAP) (June 27 2002) when potato plants were approximately 15 cm tall. Fungicides were applied until non-treated plots of susceptible controls reached about 100% diseased foliar area. The 5, 10 and 15-day interval treatments received twelve, eight and six applications in 2002, respectively. Experimental Design and Agronomic Practices All experiments were conducted at the Michigan State University Muck Soils Research Station, Bath, MI (90% organic muck soil). Soils were plowed to 20 cm depth during October following harvest of preceding crops. Soils were prepared for planting with a mechanical cultivator in early May and fertilizer applied during final bed preparation on the day of planting. Cultivars/ABL were planted on June 9, 2002 in two-row by 8 m plots (0.9 m row spacing). Fertilizers were applied in accordance with results from soil testing carried out in the spring of each year and about 250 kg N/ha (total N) was applied in two equal doses at planting and hilling. Additional micronutrients were applied according to petiole sampling recommendations and in all years. Approximately 0.2, 0.3 and 0.2 kg/ha boron, manganese and magnesium, respectively were applied as chelated formulations. Cut and whole seed pieces (75-150g) of selected cultivars and ABL were used in all experiments. The experimental design for the fungicide application interval and reduced dose rate trials was a randomized complete block design with four replications. If a fungicide treatment on a cultivar/ABL resulted in an RAUDPC that was not significantly higher than non-treated Jacqueline Lee, then it was classified as effective late blight control (E). Any fungicide treatment and cultivar/ABL combination in which the RAUDPC was significantly higher than, or was not significantly different from that of non-treated Snowden was classified as a non-effective (NE) treatment. Furthermore, if a fungicide treatment on a cultivar/ABL resulted in an RAUDPC significantly higher than that of non-treated Jacqueline Lee but significantly less than that of non- treated Snowden, the treatment was classified as providing intermediate late blight control (I). When relative humidity (RH) dipped below 80% (measured with RH sensors mounted within the canopy, described below), a mist irrigation system (described below) was turned on to maintain RH at >95% within the plant canopy. Plots were irrigated as necessary to maintain Funding CSREES Sedreal Special Grant canopy and soil moisture conditions conducive for development of foliar late blight (16) with turbine rotary garden sprinklers (Gilmour Group, Somerset, PA, U.S.A.) at 1055 l H2O ha/hr and managed under standard potato agronomic practices. Weeds were controlled by hilling and with metolachlor at 2.3 l/ha 10 days after planting (DAP), bentazon salt at 2.3 l/ha, 20 and 40 DAP and sethoxydim at 1.8 l/ha, 60 DAP. Insects were controlled with imidacloprid at 1.4 kg/ha at planting, carbaryl at 1.4 kg/ha, 31 and 55 DAP, endosulfan at 2.7 l/ha, 65 and 87 DAP and permethrin at 0.56 kg/ha, 48 DAP. Pathogen Preparation and Inoculation. Zoospore suspensions were made from P. infestans cultures of a single isolate, [MI 95-7, US8 genotype, insensitive to mefenoxam/metalaxyl, A2 mating type (13)], the predominant biotype present in the major potato growing regions of North America (12), grown on rye agar plates (3) for 14 days in the dark at 15oC. Sporangia were harvested from the rye agar plates by rinsing the mycelial/sporangial mat in cold (4oC) sterile, distilled water and scraping the mycelial/sporangial mat from the agar surface with a rubber policeman. The mycelial/sporangial suspension was stirred with a magnetic stirrer for 1 hour. The suspension was strained through four layers of cheesecloth and the concentration of sporangia was adjusted to about 1 x 103 sporangia/ml using a hemacytometer. Sporangial cultures were incubated for 2-3 hours at 4°C to stimulate zoospore release. All plots were inoculated simultaneously through an overhead sprinkler irrigation system, on July 27, 2002; by injecting the zoospore suspension of P. infestans into the irrigation water feed pipeline under 0.5 kg/cm2 CO2 pressure and applied at a rate of about 150 ml of inoculum solution/m 2 trial area. The amount and rate of inoculum applied was estimated from prior calibration of the irrigation system (described above) and was intended to expose all potato foliage to inoculum of P. infestans. Disease Evaluation and Data Analysis As soon as late blight symptoms were detected (about 7 days after inoculation, DAI), each plant within each plot was visually rated at 3 to 5 day intervals for percent leaf and stem (foliar) area with late blight lesions. The mean percent blighted foliar area per treatment was calculated. Evaluations continued until untreated plots of susceptible cultivars reached 100% foliar area diseased (39 DAI in 2001). Days after inoculation were used as a key reference point for calculation of Relative Area Under the Disease Progress Curve [RAUDPC (1)]. Microclimate Measurement Climatic variables were measured with a Davis Weather Station equipped with air temperature and humidity sensors located within the potato canopy on site (Spectrum Groweather ET Station, Spectrum Technologies, Inc., 23839 W. Andrew Road, Plainfield, IL 60544). Microclimate within the potato canopy was monitored beginning when 50% of the potato plants had emerged and ending when canopies of healthy plants reached 100% senescence. The W allin Late Blight Prediction Model (22) was developed in the Eastern United States under conditions similar to those in Michigan and was adapted to local conditions (1). Late blight disease severity values (DSV) were estimated from the Wallin Late Blight Prediction Model and accumulated from inoculation to final evaluation to estimate the conduciveness of the environment for late blight development. RESULTS Microclimate conditions Late blight developed rapidly during August; non-treated susceptible controls reached about 100% diseased foliar area 39 DAI. Accumulated DSV from inoculation to 100% senescence of healthy plants was 121. This indicated that environmental conditions were conducive to late blight development (DSV > 18) (22). Funding CSREES Sedreal Special Grant 2002 Varieties were included from the Quad State potato breeding programs. The RAUDPC values are shown in Table 1. The cultivars and ABL are ranked in order of increasing RAUDPC in untreated plots. Application of fluazinam at full rate of application at a 5-day interval resulted in effective control in all varieties. The mean RAUDPC for non-treated Jacqueline Lee and Torridon was about 0.03, which were classified as resistant. Fungicide treatments did not significantly effect late blight development in either Jacqueline Lee or Torridon The thresholds used to determine the efficacy of the fungicide and variety combination programs were RAUDPC = 1.79 and 33.1. Therefore, fungicide treatment and variety combinations with an RAUDPC < 5.52 (NSD from Snowden, 100% MRAR, 5-day application interval, RAUDPC SF5) were defined as effective (E); combinations NSD from the non-treated Snowden control (RAUDPC > 29.6) were defined as non-effective (NE); and combinations with RAUDPC values significantly different from both standards were defined as partially effective (PE); (Table 1). ABL W1355-1 and WI 1386 were effectively protected by application of the fungicide at 100% MRAR on 5 and 10-day intervals and control was PE on a 15-day interval. At the 50% MRAR, treatments were effective on a 5-day interval and PE at a 10 and 15-day intervals. These ABL was the most responsive of the susceptible cultivars/ABL to fungicide applications. Snowden, MN19515 and MN19350 were effectively protected by the fungicide at 50 and 100% of the fungicide applied at 5-day intervals and PE at 50 and 100% MRAR at 10 and 15-day intervals. Dakota Pearl and Dakota Rose were effectively protected by the fungicide at 100% MRAR at a 5-day interval. At all other rates and application intervals the fungicide was partially effective (PE). DISCUSSION The results of this study were consistent with previous studies and indicate that a combination of cultivar/ABL resistance and managed application of protective fungicides will reduce foliar late blight to acceptable levels in most situations (10,11,21). When conditions were moderately conducive to late blight development (as in 2002), reduced amounts of fluazinam were either fully or partially effective at all application rates tested on all cultivars/ABL compared to the non- treated controls. In some cultivars/ABL, 50% of the MRAR of either fungicide was sufficient to achieve acceptable control, whereas other cultivars/ABL required 100% MRAR to control late blight. On late blight susceptible cultivars, applications of fluazinam at either 10 or 15-day intervals were usualyr partially effective for controlling late blight at the doses tested. However, in the resistant cultivars Torridon and Jacqueline Lee the fungicides did not reduce the RAUDPC in comparison with untreated plots of these cultivars. The opportunity to manage late blight by applying reduced rates of fungicides at increased spray intervals to cultivars less susceptible to late blight was demonstrated in this study. In addition, the efficacy of reduced rates and increased application intervals of fungicides against other potato pathogens such as early blight has not been established and may prove to be a major constraint in the adoption of managed fungicide applications. As new cultivars with enhanced late blight resistance are developed and released it will be important to provide growers with recommendations for the most effective and economical chemical control of late blight in these new cultivars. In the future, the type of information gathered in this study will be used to develop models, based on cultivar resistance and response to fungicide application, to advise and guide growers as to which fungicide, rate and frequency of application is required to provide protection against late blight. Climatic conditions within the canopy will also impact choice of fungicide and rate and frequency of application (1). Therefore, new cultivars will need to be carefully screened in the manner described in this study, over several seasons in order to develop accurate models for fungicide application. Funding CSREES Sedreal Special Grant ACKNO WLEDGMENTS This research was funded in part by the Michigan Agricultural Experiment Station GREEEN (Generating Research and Extension to meet Economic and Environmental Needs) Project GR 99/111, Michigan Potato Industry Commission and supported in principal by the Quad State group. Special thanks to Rob Schafer for technical expertise. Mention of a brand or trade name does not constitute an endorsement. Table 1. Efficacy of fluazinam applied at reduced rates and frequencies on potato cultivars and Advanced breeding lines from North Central US potato breeding programs, MSU 2002. Cultivar/ABL Rate of Funding CSREES Sedreal Special Grant fluazinam1 Application frequency (days) 0 RAUDPC2 w3 0.0 R4 5 10 15 E5 E E E w w 0.0 0.0 vw 0.13 vw 0.06 E E E E w w 0.0 0.0 vw 0.13 w 0.06 E E E E 10.18 3.94 PE E ij 17.68 PE pqrst 15.92 PE d f 18.97 PE 14.81 PE E E E E tuvw 6.08 vw 3.92 rstu stuv 6.60 6.71 PE E PE PE nopq 7.08 6.25 qrst PE klmno PE mnop lmno 10.00 PE lmno 9.38 PE PE opqrs 15.77 PE E stuv 14.25 PE e f 22.63 PE 18.02 PE E E E E tuvw 5.52 uvw 3.44 PE E opqr rstu 8.02 6.08 PE jklmn nopq PE tuvw 14.54 PE tuvw 8.42 PE h 17.98 PE jklm 12.38 PE d hi w w vw d g j jk c de Torridon Jacqueline Lee Dakota Pearl W1355-1 MN19350 Dakota Rose WI 1386 MN19515 0 50 100 0 50 100 0 50 100 0 50 100 0 50 100 0 50 100 0 50 100 0 50 100 0 50 100 0.27 vw R 28.46 28.49 29.56 29.63 32.35 33.00 b b b b a a I I I I S S 0.0 0.0 0.06 0.13 1.83 0.94 3.69 2.92 5.15 2.98 2.27 1.44 2.04 1.65 Snowden 33.19 a S E E g jkl 3.44 1.79 rstu 13.04 PE tuvw 8.88 PE 23.04 PE 9.67 PE 1 Application rate of fluazinam as percent of manufacturer’s recommended rate (full rate = 0.6 pt/A) 2 Relative area under the disease progress curve from inoculation to 100% late blight in susceptible control (Snowden); max = 100. 3 Means followed by the same letter were not significantly different at p = 0.05; comparison between all combinations of fungicide application rate and frequency of application in all cultivars/ABL. 4 Susceptibility of nontreated control to late blight; R = Resistant, not significantly different from Jacqueline Lee (nontreated); S = Susceptible, not significantly different from Snowden (nontreated); I = Intermediate, significantly different from both Jacqueline Lee and Snowden (nontreated). 5 Effectiveness of fungicide treatment in comparison to Snowden treated with a full application rate of fluazinam at a 5-day interval or with nontreated Snowden control; E = RAUDPC NSD from treated Snowden control; PE significantly different from treated Snowden control and nontreated control; NE = NSD from Snowden nontreated control at p = 0.05. j c Funding CSREES Sedreal Special Grant LITERATURE CITED 1. Baker, K.M, J.A. Andresen, W.W. Kirk and J.M. Stein. 2000. Crop disease mitigation: Daily risk modeling for Michigan potato growers. 4 th International Conference on Integrating GIS and Environmental M ode ling (G IS/E M 4). B anff, Alb erta, C anad a, 2-8 Sept., 2000. http://lithophyte.ngdc.noaa.gov/cgi-bin/subview3.cgi/. Paper 522. 2. Campbell, C.L. 1990. Introduction to plant disease epidemiology. New York, John W iley and Sons. 3. Deahl, K.L. and S.P. Demuth. 1995. Identification of mating types and metalaxyl resistance in North- American populations of Phytophthora infestans. American Pot. J. 74(2): 35-49. 4. Douches, D.S., W.W. Kirk, K. Jastrzebski, C. Long and R. Hammerschmidt. 1997. Susceptibility of potato varieties and advanced breeding lines (Solanum tuberosum L.) to Phytophthora infestans (Mont.) de Bary in greenhouse screenings. American Pot. J 74:75-86. 5. Douches, D.S., R.W. Chase, K. Jastrzebski, R. Hammerschmidt. W.W. Kirk, C. Long, K. Walters and J. Coombs. 1997. Potato Variety Evaluations. Michigan Potato Research Report: 29:5-32. 6. Douches, D.S. R.W. Chase, K. Jastrzebski, R. Hammerschmidt, W.W. Kirk, C. Long, K. Walters, J. Coombs and J. Greyerbiehl. 1998. Potato Variety Evaluations. Michigan Potato Research Report: 30:11-35. 7. Douches, D.S. R.W. Chase, K. Jastrzebski, R. Hammerschmidt, W.W. Kirk, C. Long, K. Walters, J. Coombs and J. Greyerbiehl. 1999. Potato Variety Evaluations. Michigan Potato Research Report: 31:1-45 8. Douches, J. Coombs, C. Long, K. Zarka, K. W alters and D. Bisognin. 2000. Potato Variety Evaluations. Michigan Potato Research Report: 32:5-54. The 9. Environmental Protection Agency. 1996. http://www.epa.gov/opppsps1/fqpa/. food quality protection act of 1996. 10. Fry, W.E. 1977a. Integrated effects of polygenic resistance and protective fungicide on development of potato late blight. Phytopathology 65:908-911. 11. Fry, W.E. 1977b. Integrated control of potato late blight- effects of polygenic resistance and techniques of timing fungicide applications. Phytopathology 67:415-420. 12. Fry, W.E. and S.B. Goodwin. 1997. Re-emergence of potato and tomato late blight in the United States. Plant Dis. 81:1349-1357. 13. Goodwin, S.B., R.E. Schneider and W .E. Fry. 1995. Use of cellulose-acetate electrophoresis for rapid identification of allozyme genotypes of Phytophthora infestans. Plant Dis. 79:1181-1185. 14. Gray, J.I. and M.E. W halon. 1996. The assessment of pesticides at risk in the future of Michigan food and feed plant agriculture: A process. East Lansing, Michigan, Michigan Agricultural Experiment Station: Special Report: 15. 15. Lambert, D.H. and A.I. Currier. 1997. Differences in tuber rot development for North American clones of Phytophthora infestans. American Pot. J. 74:39-43. 16. Madden, L.V. and G. Hughes. 1995. Plant disease incidence: distributions, heterogeneity, and temporal analysis. Annual Review of Phytopathology 33:529-564. 17. Schwinn FJ and Margot P, Control with chemicals, In Advances in plant pathology. Phytophthora infestans, the cause of potato late blight, 7, ed. Ingram DS & PH Williams. Academic Press Limited, San Diego, CA USA,, pp. 225-265 (1991). 18. Secor, G.A. and N.C. Gudmestad. 1999. Managing fungal diseases of potato. Can. J. Plant Pathol. 21:212-221. Agricultural Genomics 3:4-6. 19. Sender, A.J. 2000. TIGR develops "potato chip" microarray to aid hunt for disease resistance genes. 20. Syngenta US Website. 2001. http://www.syngenta.com/. 21. Van der Plank, J.E. 1968. Disease resistance in plants. New York, Academic Press. 22. Wallin, J.R. 1953. The production and survival of sporangia of Phytophthora infestans on tomato and potato plants in the field. Phytopathology 43:505-508. 23. Zeneca UK W ebsite. 2001. http://www.zeneca-crop.co.uk/. POTATO (Solanum tuberosum L.‘FL1879’) Late blight; Phytophthora infestans Funding: Industry W. W. Kirk, R. L Schafer and D. Berry Department of Plant Pathology Michigan State University East Lansing, MI 48824 Evaluation of Headline programs for potato late blight control, 2002. Potatoes [cut seed, treated with Maxim M Z 0.5D (0.5 lb/cwt)] were planted at the Michigan State University M uck Soils Experimental Station, Bath, MI on 5 Jun into two-row by 25-ft plots (34-in row spacing), separated by a five-foot unplanted row and replicated four times in a randomized complete block design. Plots were irrigated as needed with sprinklers and were hilled immediately before sprays began. All rows were inoculated (3.4 fl oz/25-ft row) with a zoospore suspension of Phytophthora infestans US8 biotype (insensitive to mefenoxam, A2 mating type) at 104 spores/fl oz on 27 Jul. All fungicides in this trial were applied on a 7-day interval from 23 Jun to 21 Aug (9 applications) with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Weeds were controlled by hilling and with Dual 8E (2 pt/A on 20 Jun), Basagran (2 pt/A on 20 Jun and 15 Jul) and Poast (1.5 pt/A on 28 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 15 Jun), Sevin 80S (1.25 lb/A on 1 and 28 Jul), Thiodan 3EC (2.33 pt/A on 1 and 21 Aug) and Pounce 3.2EC (8 oz/A on 28 Jul). Plots were rated visually for percentage foliar area affected by late blight on 27 Jul; 6, 12, 20, 27 Aug [6 days after final application (DAFA)] and 7 Sep (17 DAFA) when there was 100% foliar infection in the untreated plots. The relative area under the disease progress curve was calculated for each treatment from date of inoculation, 27 Jul to 7 Sep, a period of 42 days. Vines were killed with Reglone 2EC (1 pt/A on 8 Sep). Maximum and minimum air temperature (oF) were 92.1 and 64.4 (Jun), 92.5 and 72.5 (Jul), 88.7 and 68.6 (Aug) and 91.3 and 64.8. Maximum and minimum soil temperature (oF) were 82.0 and 70.8 (Jun), 84.6 and 74.2 (Jul), 84.3 and 74.2 (Aug) and 82.3 and 69.3 (to 7 Sep). Precipitation was 0.32" (Jun), 1.14" (Jul), 0.41" (Aug) and 0.0" (to 7 Sep). Plots were irrigated to supplement precipitation to about 1"/A/4 day period with overhead sprinkler irrigation. Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 100% foliar infection by 7 Sep. From 50% emergence to harvest, 100 late blight disease severity values were accumulated (base 80% ambient relative humidity). Taking 31 days after inoculation (DAI) as a key reference point, all fungicide programs reduced the foliar late blight significantly compared to the untreated control. Taking 42 DAI as a key reference point, there was almost complete defoliation of the untreated control due to late blight and all fungicide programs had significantly less foliar late blight than the untreated control. Programs 6 and 8 had significantly greater foliar late blight than all other programs. Program 7 had significantly greater foliar late blight than programs with 5.3% or less foliar late blight. All other programs were not significantly different from each other. All fungicide programs significantly reduced the average amount of foliar late blight over the season (RAUDPC) compared to the untreated control. Application programs 6 and 8 had significantly higher RAUDPC values than all other programs. All other programs had RAUDPC values less than 1.70 and were not significantly different from each other. Phytotoxicity was not noted in any of the treatments. Treatment and rate/acre 1 Headline 2SC 0.58 pt (A,B,C,D,E,F,G,H,I)w......................….......................... 2 Headline 2SC 0.77 pt (A,B,C,D,E,F,G,H,I)........................….......................... 3 Headline 2SC 0.58 pt (A,C,E,G,I) BAS510 70WDG 0.14 lb + BAS545 400SC 0.17 pt + Silwet 0.13 pt (B,D,F,H)............................................................................... 4 BAS536F 18.7 WP 1.66 lb (A,B,C,D,E,F,G,I)................................................. 5 BAS536F 18.7 WP 1.66 lb + Silwet 70SC 0.13 pt (A,B,C,D,E,F,G,H,I)......... 6 BAS536F 18.7 WP 1.66 lb (A,C,E,G,I) Foliar late blight (%) 31 DAIz 6 DAFAy 42 DAI 17 DAFA 1.5 1.6 1.8 2.9 1.0 b v b b b b 3.3 4.5 5.3 6.8 6.0 d d d cd cd RAUDPCx 0 - 42 DAI 0.58 0.72 0.78 1.12 0.71 c c c c c BAS510 70WDG 0.14 lb + BAS545 400SC 0.17 pt + Silwet 0.13 pt (B,D,F,H)................................................................................... 7 BAS536F 18.7 WP 1.66 lb (A,C,E,G,I); Bravo WS SC 1.5 pt (B,D,F,H)........ 8 Quadris 2.08SC 0.96 pt (A,C,E,G,I); Bravo WS SC 1.5 pt (B,D,F,H)............. 9 Untreated.......................................................................................................... z Days after inoculation with Phytophthora infestans, US8, A2. y Days after final application of fungicide. x RAUDPC, relative area under the disease progress curve calculated from day of inoculation to last evaluation of late blight. Maximum value = 100. w Application dates: A= 23 Jun; B= 1 Jul; C= 8 Jul; D= 15 Jul; E= 22 Jul; F= 30 Jul; G= 7 Aug; H= 14 Aug; I= 21Aug. v Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). b 25.0 c 12.0 23.8 b 100.0 a b 3.31 c 1.70 3.53 b 34.92 a 7.0 3.6 8.3 87.5 b b b a POTATO (Solanum tuberosum L.‘FL1879’) Late blight; Phytophthora infestans Funding: Industry W. W. Kirk, R. L Schafer and D. Berry Department of Plant Pathology Michigan State University East Lansing, MI 48824 Evaluation of Reason, Scala, Gavel, and EBDC-based programs for potato late blight control, 2002. Potatoes [cut seed, treated with Maxim M Z 0.5D (0.5 lb/cwt)] were planted at the Michigan State University M uck Soils Experimental Station, Bath, MI on 5 Jun into two-row by 25-ft plots (34-in row spacing), separated by a five-foot unplanted row and replicated four times in a randomized complete block design. Plots were irrigated as needed with sprinklers and were hilled immediately before sprays began. All rows were inoculated (3.4 fl oz/25-ft row) with a zoospore suspension of Phytophthora infestans US8 biotype (insensitive to mefenoxam, A2 mating type) at 104 spores/fl oz on 27 Jul. All fungicides in this trial were applied on a 7-day interval from 23 Jun to 21 Aug (9 applications) with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Weeds were controlled by hilling and with Dual 8E (2 pt/A on 20 Jun), Basagran (2 pt/A on 20 Jun and 15 Jul) and Poast (1.5 pt/A on 28 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 15 Jun), Sevin 80S (1.25 lb/A on 1 and 28 Jul), Thiodan 3EC (2.33 pt/A on 1 and 21 Aug) and Pounce 3.2EC (8 oz/A on 28 Jul). Plots were rated visually for percentage foliar area affected by late blight on 27 Jul; 6, 12, 20, 27 Aug; 3 Sep [13 days after final application (DAFA)] and 7 Sep (DAFA) when there was 100% foliar infection in the untreated plots. The relative area under the disease progress curve was calculated for each treatment from date of inoculation, 27 Jul to 7 Sep, a period of 42 days. Vines were killed with Reglone 2EC (1 pt/A on 8 Sep). Plots (2 x 25-ft row) were harvested on 5 Oct and individual treatments were weighed and graded. Maximum and minimum air temperature (oF) were 92.1 and 64.4 (Jun), 92.5 and 72.5 (Jul), 88.7 and 68.6 (Aug) and 91.3 and 64.8. Maximum and minimum soil temperature (oF) were 82.0 and 70.8 (Jun), 84.6 and 74.2 (Jul), 84.3 and 74.2 (Aug) and 82.3 and 69.3 (to 7 Sep). Precipitation was 0.32" (Jun), 1.14" (Jul), 0.41" (Aug) and 0.0" (to 7 Sep). Plots were irrigated to supplement precipitation to about 1"/A/4 day period with overhead sprinkler irrigation. Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 100% foliar infection by 7 Sep. From 50% emergence to harvest, 100 late blight disease severity values were accumulated (base 80% ambient relative humidity). Taking 38 days after inoculation (DAI) as a key reference point, all fungicide programs reduced the foliar late blight significantly compared to the untreated control. Program 10 had significantly greater foliar late blight than all other programs. All other programs were not significantly different from each other. T aking 42 DAI as a key reference point, there was complete defoliation of the untreated control due to late blight and all fungicide programs had significantly less foliar late blight than the untreated control. Program 6 had significantly greater foliar late blight than all other programs. Programs 1 and 4 had significantly less foliar late blight than all other programs except 7 and 9. All remaining programs were not significantly different from each other. All fungicide programs significantly reduced the average amount of foliar late blight over the season (RAUDPC, 0 to 42 DAI) compared to the untreated control. Application program 6 had a significantly higher RAUDPC value than all other programs with values of 4.17 or lower. Program 10 had a significantly higher RAUDPC value than programs with values of 2.31 or lower. All other programs were not significantly different from each other. Programs 5, 6, 7, 8 and 9 had significantly higher US1 yield than the untreated control and programs 5, 7 and 9 had significantly higher US1 yield than program 2. No other programs had US1 yields significantly different than the untreated control. There were no significant differences among treatments in terms of total yield. Phytotoxicity was not noted in any of the treatments. Foliar late blight (%) RAUDPCx 38 DAIz 0 - 42 DAI 13 DAFAy 42 DAI 17 DAFA Funding: Industry Yield (cwt/A) US1 Total 13.8 d 22.5 c 13.8 d 2.72 cd 237 abc 324 a 3.44 cd 230 ab 301 a 1.83 d 248 abc 339 a 21.3 c 2.48 cd 240 abc 322 a 21.3 c 48.8 b 20.0 cd 3.50 cd 6.87 b 3.01 cd 274 c 261 bc 271 c 346 a 331 a 335 a Treatment and rate/acre 1 Bravo WS 6SC 0.76 pt (A,B,C); 1.5 pt (D,E,F,G,H,I)w.............................. 4.5 dv 2 Bravo WS 6SC 0.76 pt (A,B,C) Reason 4SC 0.75 pt + Bond 3.8SC 0.25 pt (D,E,F,G,H,I)......................... 4.5 D 3 Bravo WS 6SC 0.76 pt (A,B,C) 4 Bravo WS 6SC 0.76 pt (A,B,C) Reason 4SC 0.51 pt + Scala 3.2SC 0.64 pt (D,E,F,G,H,I).......................... 4.5 D Reason 4SC 0.51 pt + Bond 3.8SC 0.25 pt (D,E,F,G) Bravo WS 6SC 0.76 pt + Previcur 6SC 1.2 pt (H,I)................................... 7.8 cd 5 Bravo WS 6SC 0.76 pt (A,B,C,H,I) Bravo WS 6SC 0.76 pt + Previcur 6SC 1.2 pt (H,I)................................... 8.3 cd 6 TD 2390 5.8WDG 6.0 lb (A,B,C,D,E,F,G,H,I).......................................... 8.3 cd 7 Penncozeb 75WP 2.0 lb (A,B,C,D,E,F,G,H,I)........................................... 9.0 cd 8 Gavel 75WDG 6.0 lb (A,B,F,G,H,I) Dithane RS 75DF 2.0 lb (C,D,E)................................................................ 9.5 cd 9 Gavel 75WDG 6.0 lb (A,B,C,D,E,F,G,H,I)................................................ 10.8 C 10 Dithane RS 75DF 2.0 lb (A,B,C,D,E,F,G,H,I).......................................... 16.3 B 11 Untreated.................................................................................................... 91.5 A z Days after inoculation with Phytophthora infestans, US8, A2. y Days after final application of fungicide. x RAUDPC, relative area under the disease progress curve calculated from day of inoculation to last evaluation of late blight. Maximum value = 100. w Application dates: A= 23 Jun; B= 1 Jul; C= 8 Jul; D= 15 Jul; E= 22 Jul; F= 30 Jul; G= 7 Aug; H= 14 Aug; I= 21Aug. v Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). 251 bc 277 c 239 abc 210 a 3.22 cd 2.31 d 4.17 c 27.60a 23.8 c 17.5 cd 23.8 c 100.0a 336 a 353 a 314 a 280 a POTATO (Solanum tuberosum L.‘Pike’) Late blight; Phytophthora infestans Early blight; Alternaria solani White mold; Sclerotinia sclerotiorum Gray mold; Botrytis cinerea Funding: Industry W. W. Kirk, R. L Schafer and D. Berry Department of Plant Pathology Michigan State University East Lansing, MI 48824 Evaluation of Sonata-based products and fungicide programs for foliar disease control, 2002 Potatoes (cut seed) were planted at the Michigan State University Muck Soils Experimental Station, Bath, MI on 5 Jun into two-row by 25-ft plots (34-in row spacing) replicated four times in a randomized complete block design. The two-row beds were separated by a five-foot unplanted row. Plots were irrigated as needed with sprinklers and were hilled immediately before sprays began. All fungicides in this trial were applied on a 7-day interval from 23 Jun to 21 Aug (total 9 applications) from 1 Jul to 27 Aug with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Weeds were controlled by hilling and with Dual 8E (2 pt/A on 20 Jun), Basagran (2 pt/A on 20 Jun and 15 Jul) and Poast (1.5 pt/A on 28 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 15 Jun), Sevin 80S (1.25 lb/A on 1 and 28 Jul), Thiodan 3EC (2.33 pt/A on 1 and 21 Aug) and Pounce 3.2EC (8 oz/A on 28 Jul). Plots were rated visually for percentage foliar area affected by early blight and white mold on 18, 31 Jul; 24 Aug and 26 Sep. A single evaluation of foliar late blight and Botrytis foliar blight was made on 26 Sep. The relative area under the disease progress curve was calculated for each treatment from 30 day after planting (DAP) until 113 DAP, a period of 83 days. Vines were killed with Reglone 2EC (1 pt/A on 3 Oct). Plots (25-ft row) were harvested on 12 Oct and individual treatments were weighed and graded. Maximum and minimum air temperature (oF) were 92.1 and 64.4 (Jun), 92.5 and 72.5 (Jul), 88.7 and 68.6 (Aug) and 91.3 and 64.8. Maximum and minimum soil temperature (oF) were 82.0 and 70.8 (Jun), 84.6 and 74.2 (Jul), 84.3 and 74.2 (Aug) and 82.3 and 69.3 (to 7 Sep). Precipitation was 0.32" (Jun), 1.14" (Jul), 0.41" (Aug) and 0.0" (to 7 Sep). Plots were irrigated to supplement precipitation to about 1"/A/4 day period with overhead sprinkler irrigation. Early blight developed slowly during Jul and Aug then increased during Sep, but untreated controls only reached about 20% foliar area affected for early blight 113 DAP. Taking 113 DAP as a key reference point all application programs reduced the early blight foliar infection significantly compared to the untreated control. Programs 9 and 10 had significantly less foliar early blight than programs with 9.5% or more foliar early blight. Taking 30 - 113 DAP as a disease development period, all programs had significantly less foliar early blight than the untreated control. Program 9 had the least early blight over the evaluation period and significantly less than programs 1, 2, 3, 4, 5 and 7. Program 10 had significantly less early blight over the evaluation period than programs 1, 2, 3, 4 and 7. Programs 1, 2 and 7 had the most early blight over the evaluation period but were not significantly different from programs 3, 4 and 5. White mold developed slowly during Jul and Aug then increased during Sep, but untreated controls only reached about 16% stem area affected 113 DAP. Taking 113 DAP as a key reference point all application programs reduced stem white mold significantly compared to the untreated control. Application program 8 had the least stem white mold (2.5% severity) but was not significantly different from programs 1, 2, 3, 5 and 6. There was no significant difference among programs with 3.8 to 7.5% stem white mold (programs 1, 2, 3, 5, 6, 7 and 10). There was no significant difference among programs with 7.5 to 9.5% stem white mold (programs 4, 9 and 10). Taking 30 - 113 DAP as a disease development period, all programs had significantly less stem white mold than the untreated control. Program 8 had the least white mold over the evaluation period and significantly less than programs 4, 7, 9 and 10 but not significantly different from programs 1, 2, 3, 5 and 6. Late blight spread to the trial area from adjacent trials in which late blight was present about 90 DAP. Untreated control plots had an average of 31.3% foliar late blight 113 DAP. All programs except program 1 had significantly less foliar late blight compared to the untreated control. Programs 6, 7 and 9 had significantly less foliar late blight than all other programs. Gray mold reached about 35% in the untreated control 113 DAP and all application programs reduced the gray mold foliar infection significantly compared to the untreated control. Programs 8 and 9 had significantly less gray mold than programs with 10.8% or more gray mold. Program 7 had significantly greater gray mold than all other programs except program 2. Yield was not correlated with increasing severity of foliar early blight, white mold, late blight or gray mold and there was no significant difference among any treatments in terms of marketable yield. Phytotoxicity was not noted in any of the treatments. Funding: Industry Foliar late blight (%)x 113 DAP Foliar gray mold (%)w 113 DAP Yield (cwt/A) US1 Foliar early blight (%) Stem white mold (% severity) 113 DAPz RAUDPCy 30 - 113 113 DAP RAUDPC 30 - 113 DAP 5.0 b 5.0 b 3.8 de 4.0 de DAP 2.5 d 2.8 cd 26.3 ab 21.3 bcd 6.0 def 13.3 bc 3.9 bc 4.3 cde 2.7 cd 18.8 bcd 11.3 cd 3.8 bcd 9.5 b 5.3 b 22.5 bc 11.3 cd 315 a 321 a 351 a 353 a Treatment and rate/acre 1 QRD 286 1SC 4 pt (A,B,C,D,E,F,G,H,I)v.............. 12.5 bu 2 QRD 286 1SC 8 pt (A,B,C,D,E,F,G,H,I)................ 12.5 b 3 QRD 137 1WP 2 lb + Kocide 2000 50DF 2 lb (A,B,C,D,E,F,G,H,I)......... 9.5 b 4 QRD 137 1WP 4 lb + 5 Quadris 2SC 0.38 pt + Kocide 2000 50DF 2 lb (A,B,C,D,E,F,G,H,I)......... 9.5 bc Bravo WS 2SC 1.5 pt (A,C) QRD 286 1SC 8 pt (B,D) Bravo WS 2SC 1.5 pt (E,F,G,H,I)........................... 6 Quadris 2SC 0.38375 pt + Bravo WS 2SC 1.5 pt (A,C) Bravo WS 2SC 1.5 pt (D,E,F,G,H,I)....................... 7 Penncozeb 75DF 2 lb (A,B) 8.8 bcd 3.5 bcde 5.0 cde 3.3 bcd 13.8 d 10.8 cd 350 a 7.5 cd 2.9 cdef 4.3 cde 2.9 cd 2.5 e 10.0 cde 323 a Topsin-M 70WP 1 lb + Penncozeb 75DF 2 lb (C,D) Bravo WS 2SC 1.5 pt (E,F,G,H,I)........................... 12.5 b 8 BAS510 70WDG 0.41 lb (A,B,C,D,E,F,G,H,I)....... 5.0 cd 4.3 d 9 Headline 2SC 0.38 pt (A,B,C,D,E,F,G,H,I)............ 10 Quadris 2SC 0.38 pt (A,B,C,D,E,F,G,H,I).............. 4.5 d 11 Untreated................................................................. 22.5 a z Days after planting (5 Jun). y RAUDPC, relative area under the disease progress curve calculated from 30 DAP to 113 DAP. x Late blight leaf area diseased, inoculum spread from inoculated plots within 10 m of trial plot, [Phytophthora infestans (US8, A2 mating type, mefenoxam-insensitive)]. w Botrytis cinerea, natural inoculum, percent leaf area diseased. v Application dates: A= 23 Jun; B= 1 Jul; C= 8 Jul; D= 15 Jul; E= 22 Jul; F= 30 Jul; G= 7 Aug; H= 14 Aug; I= 21Aug. u Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). 17.5 b 4.5 ef 4.3 f 8.8 cdef 35.0 a 5.0 cd 2.5 e 8.3 bc 7.5 bcd 16.3 a 4.8 b 2.0 def 1.6 f 1.9 ef 8.9 a 4.5 e 16.3 cd 3.3 e 15.8 cd 31.3 a 3.6 bc 1.4 d 4.6 bc 4.4 bc 9.0 a 331 a 348 a 344 a 357 a 322 a POTATO (Solanum tuberosum L.‘FL1879’) Late blight; Phytophthora infestans Funding: Industry W. W. Kirk, R. L Schafer and D. Berry Department of Plant Pathology Michigan State University East Lansing, MI 48824 Evaluation of Headline, Ranman, EBDC and chlorothalonil-based programs for potato late blight control, 2002. Potatoes [cut seed, treated with Maxim M Z 0.5D (0.5 lb/cwt)] were planted at the Michigan State University M uck Soils Experimental Station, Bath, MI on 5 Jun into two-row by 25-ft plots (34-in row spacing), separated by a five-foot unplanted row and replicated four times in a randomized complete block design. Plots were irrigated as needed with sprinklers and were hilled immediately before sprays began. All rows were inoculated (3.4 fl oz/25-ft row) with a zoospore suspension of Phytophthora infestans US8 biotype (insensitive to mefenoxam, A2 mating type) at 104 spores/fl oz on 27 Jul. All fungicides in this trial were applied on a 7-day interval from 23 Jun to 21 Aug (9 applications) with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Weeds were controlled by hilling and with Dual 8E (2 pt/A on 20 Jun), Basagran (2 pt/A on 20 Jun and 15 Jul) and Poast (1.5 pt/A on 28 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 15 Jun), Sevin 80S (1.25 lb/A on 1 and 28 Jul), Thiodan 3EC (2.33 pt/A on 1 and 21 Aug) and Pounce 3.2EC (8 oz/A on 28 Jul). Plots were rated visually for percentage foliar area affected by late blight on 27 Jul; 6, 12, 20, 27 Aug [6 days after final application (DAFA)] and 7 Sep (17 DAFA) when there was 100% foliar infection in the untreated plots. The relative area under the disease progress curve was calculated for each treatment from date of inoculation, 27 Jul to 7 Sep, a period of 42 days. Vines were killed with Reglone 2EC (1 pt/A on 8 Sep). Plots (2 x 25-ft row) were harvested on 5 Oct and individual treatments were weighed and graded. Maximum and minimum air temperature (oF) were 92.1 and 64.4 (Jun), 92.5 and 72.5 (Jul), 88.7 and 68.6 (Aug) and 91.3 and 64.8. M aximum and minimum soil temperature (oF) were 82.0 and 70.8 (Jun), 84.6 and 74.2 (Jul), 84.3 and 74.2 (Aug) and 82.3 and 69.3 (to 7 Sep). Precipitation was 0.32" (Jun), 1.14" (Jul), 0.41" (Aug) and 0.0" (to 7 Sep). Plots were irrigated to supplement precipitation to about 1"/A/4 day period with overhead sprinkler irrigation. Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 100% foliar infection by 7 Sep. From 50% emergence to harvest, 100 late blight disease severity values were accumulated (base 80% ambient relative humidity). Taking 31 days after inoculation (DAI) as a key reference point, all fungicide programs reduced the foliar late blight significantly compared to the untreated control. Programs 12 and 15 had significantly greater foliar late blight than programs with less than 1.75% foliar late blight. Taking 42 DAI as a key reference point, there was complete defoliation of the untreated control due to late blight and all fungicide programs had significantly less foliar late blight than the untreated control. Program 12 had significantly greater foliar late blight than all other programs except 1 and 15. Programs 1 and 15 had significantly greater foliar than late blight programs with 5.0% foliar late blight. Programs 2, 5, 11 and 22 had significantly more foliar late blight than programs with less than 3.75% foliar late blight. All other programs were not significantly different from each other. All fungicide programs significantly reduced the average amount of foliar late blight over the season (RAUDPC, 0 to 37 DAI) compared to the untreated control. Application programs 12 had a significantly higher RAUDPC value than all other programs with values below 0.6. All other programs except program 15 had RAUDPC values < 1.19 and were not significantly different from each other. All programs had significantly greater US1 yield compared to the untreated control. There were no significant differences between programs with US1 yield from 245 to 278 cwt/A and programs with US1 yield from 229 to 260 cwt/A. All programs except program 19 had significantly greater total yield compared to the untreated control. There were no significant differences between programs with total yield from 292 to 333 cwt/A and programs from 316 to 358 cwt/A. Phytotoxicity was not noted in any of the treatments. Foliar late blight (%) RAUDPCx 0 - 42 DAI 31 DAIz 6 DAFAy Treatment and rate/A 1 Echo ZN 6SC 2.13 pt (A,B,C,D,E,F,G,H,I)w.............................................. 2.62 bcdv 2 Echo ZN 6SC 1.5 pt + Quadris 2.08SC 0.28 pt (A,C) 42DAI 13 DAFA 1.19 bcd 9.00 bc Funding: Industry Yield (cwt/A) US1 Total 275 a 357 a Echo ZN 6SC 1.5 pt (B,D,E,H.I) Polyram 80WP 2.0 lb + Super Tin 80WP 0.23 lb (F,G)............................. 1.60 cd 3 Echo ZN 6SC 2.13 pt (A,B,D,F,H,I);Gem 50WP 0.19 lb (C,E,G)............. 1.75 cd 4 Ranman 40SC 0.13 pt + Silwet I-77 6SC 0.1 pt (A,B,C,D,E,F,G,H,I)...... 1.75 cd 5 Ranman 40SC 0.17 + Silwet I-77 6SC 0.1 pt (A,B,C,D,E,F,G,H,I)........... 3.25 bc 6 Ranman 40SC 0.13 pt + Silwet I-77 6SC 0.1 pt (A,B,D,F,H,I) BAS536F 18.7 WP 1.66 lb (C,E,G)............................................................ 0.87 cd 7 Ranman 40SC 0.17 pt + Silwet I-77 6SC 0.1 pt (A,B,D,F,H,I) BAS536F 18.7 WP 1.66 lb (C,E,G)............................................................ 0.80 d 8 Ranman 40SC 0.13 pt + Silwet I-77 6SC 0.1 pt (A,D,G) Headline 2SC 0.77 pt (B.E.H) BAS550 50WP 0.4 lb + Polyram 80WP 2.0 lb (C,F,I)............................... 0.77 d 9 Ranman 40SC 0.13 pt (A,C,E,G,I); Headline 2SC 0.77 pt (B.D,F,H)........ 1.07 cd 10 Headline 2SC 0.77 pt (A,C); Bravo WS 6SC 1.5 pt (B,H) Polyram 80WP 2.0 lb + Agri Tin 80WP 0.16 lb (D,E,F,G.I)...................... 1.58 cd 11 Headline 2SC 0.77 pt (A,C); Bravo WS 6SC 1.5 pt (B,H) Polyram 80WP 2.0 lb + Acrobat 50WP 0.4 lb (D,E,F,G.I)......................... 2.35 bcd 12 Bravo WS 6SC 1.5 pt (A,C,E,G,I) Messenger 3WDG 0.38 lb (B.D,F,H)......................................................... 4.25 b 13 Bravo WS 6SC 1.5 pt + Champ DP 4.6FL2.67 pt (A,B,C,D) Dithane RS 75DF 1.5 lb + Champ DP 4.6FL2.0 pt + Agri Tin 80WP 0.13 lb (E,F,G.I)................................................................ 1.12 cd 14 Bravo WS 6SC 1.5 pt + Champ DP 4.6FL2.67 pt (A,B,C,D) Dithane RS 75DF 1.5 lb + Champ DP 4.6FL2.0 pt + Phostrol 53.6SC 8.0 pt (E,F,G.I)................................................................. 0.83 cd 15 Bravo WS 6SC 1.5 pt + Champ DP 4.6FL2.67 pt (A,B,C,D) Champ DP 4.6FL2.0 pt + Phostrol 53.6SC 8.0 pt (E,F,G.I)....................... 4.25 b 16 Quadris 2.08SC 0.4 pt + Bravo WS SC 1.5 pt (A) Bravo WS 6SC 1.5 pt + Champ DP 4.6FL2.67 pt (B,D) Bravo WS 6SC 1.5 pt + Acrobat 50WP 0.4 lb (C,H) Dithane RS 75DF 1.5 lb + Champ DP 4.6FL2.0 pt + Agri Tin 80WP 0.16 lb + Phostrol 53.6SC 8.0 pt (E,F,G.I)........................ 0.65 d 17 Quadris 2.08SC 0.4 pt + Equus SC 1.5 pt (A); Equus SC 1.5 pt (B,D) Equus SC 1.5 pt + Acrobat 50WP 0.4 lb (C,H) Equus SC 1.5 pt + Kocide4.5FL 2.67 pt (E,F,G.I)..................................... 1.75 cd 18 Quadris 2.08SC 0.4 pt + Equus SC 1.5 pt (A,C,E); Equus SC 1.5 pt (B,D) Manzate 75WP 2.0 lb + Super Tin 80WP 0.16 lb (F,G,H,I)....................... 0.70 d 19 Quadris 2.08SC 0.4 pt + Equus SC 1.5 pt (A,C,E) Equus SC 1.5 pt (B,D) Equus SC 1.5 pt + Super Tin 80WP 0.16 lb (F,G,H,I)................................ 1.20 cd 20 Headline 2SC 0.77 pt + Polyram 80WP 2.0 lb (A,B,C) Ranman 40SC 0.13 pt + Polyram 80WP 2.0 lb (D,E,F,G) Polyram 80WP 2.0 lb + Agri Tin 80WP 0.16 lb (H,I)................................ 1.20 cd 21 Headline 2SC 0.77 pt + Polyram 80WP 2.0 lb (A,B,C) Acrobat 50WP 0.4 lb + Polyram 80WP 2.0 lb (D,E,F,G) Polyram 80WP 2.0 lb + Agri Tin 80WP 0.16 lb (H,I)................................ 1.25 cd 22 Headline 2SC 0.77 pt + Polyram 80WP 2.0 lb (A,B,C) Curzate 60DF 0.2 lb + Polyram 80WP 2.0 lb (D,E,F,G) Polyram 80WP 2.0 lb + Agri Tin 80WP 0.16 lb (H,I)................................ 1.50 cd 6.50 cd 5.00 de 5.00 de 6.50 cd 0.81 bcd 0.73 bcd 0.72 bcd 1.11 bcd 278 a 259 abcd 240 bcd 246 abcd 354 a 342 ab 318 abc 316 abc 4.50 de 0.53 cd 237 cd 323 abc 3.25 e 0.41 cd 276 a 344 ab 2.50 e 3.75 e 0.34 cd 0.49 cd 273 ab 264 abc 337 ab 335 ab 4.75 de 0.73 bcd 269 ab 335 ab 6.75 cd 0.97 bcd 237 cd 321 abc 13.00b 1.90 b 258 abcd 340 ab 3.00 e 0.45 cd 230 cd 306 bc 2.00 e 0.31 cd 260 abcd 337 ab 9.00 bc 1.53 bc 237 cd 324 abc 1.50 e 0.24 d 251 abcd 327 abc 5.25 cde 0.73 bcd 247 abcd 317 abc 2.00 e 0.29 cd 245 abcd 308 bc 4.75 de 0.60 cd 229 d 292 cd 3.50 e 0.50 cd 241 bcd 309 bc 4.00 de 0.57 cd 273 ab 348 ab 8.75 cd 0.99 bcd 234 cd 316 abc 23 Headline 2SC 0.77 pt + Polyram 80WP 2.0 lb (A,B,C) Previcur 6SC 1.2 pt + Polyram 80WP 2.0 lb (D,E,F,G) Polyram 80WP 2.0 lb + Agri Tin 80WP 0.16 lb (H,I)................................ 0.92 cd 24 Untreated.................................................................................................... 83.75a z Days after inoculation with Phytophthora infestans, US8, A2. YDays after final application of fungicide. X RAUDPC, relative area under the disease progress curve calculated from day of inoculation to last evaluation of late blight. Maximum value of 100. W Application dates: A= 23 Jun; B= 1 Jul; C= 8 Jul; D= 15 Jul; E= 22 Jul; F= 30 Jul; G= 7 Aug; H= 14 Aug; I= 21Aug. V Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). 333 abc 263 d 4.00 de 100.0a 0.52 cd 27.86a 264 ab 182 e POTATO (Solanum tuberosum L.‘FL1879’) Late blight; Phytophthora infestans Early blight; Alternaria alternata Funding: Industry W. W. Kirk, R. L Schafer and D. Berry Department of Plant Pathology Michigan State University East Lansing, MI 48824 Evaluation of Tanos, Famoxate and Curzate programs for potato late blight and Alternaria spp. control, 2002. Potatoes [cut seed, treated with Maxim M Z 0.5D (0.5 lb/cwt)] were planted at the Michigan State University M uck Soils Experimental Station, Bath, MI on 5 Jun into two-row by 25-ft plots (34-in row spacing), separated by a five-foot unplanted row and replicated four times in a randomized complete block design. Plots were irrigated as needed with sprinklers and were hilled immediately before sprays began. All rows were inoculated (3.4 fl oz/25-ft row) with a zoospore suspension of Phytophthora infestans US8 biotype (insensitive to mefenoxam, A2 mating type) at 104 spores/fl oz on 27 Jul. All fungicides in this trial were applied on a 7-day interval from 23 Jun to 21 Aug (9 applications) with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Weeds were controlled by hilling and with Dual 8E (2 pt/A on 20 Jun), Basagran (2 pt/A on 20 Jun and 15 Jul) and Poast (1.5 pt/A on 28 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 15 Jun), Sevin 80S (1.25 lb/A on 1 and 28 Jul), Thiodan 3EC (2.33 pt/A on 1 and 21 Aug) and Pounce 3.2EC (8 oz/A on 28 Jul). Plots were rated visually for percentage foliar area affected by late blight on 27 Jul; 6, 12, 20, 27 Aug; 3 Sep [13 days after final application (DAFA)] and 7 Sep (17 DAFA) when there was 100% foliar infection in the untreated plots and for Alternaria spp. foliar blight on 7 Sep (17 DAFA). The relative area under the disease progress curve was calculated for each treatment from date of inoculation, 27 Jul to 7 Sep, a period of 42 days. Vines were killed with Reglone 2EC (1 pt/A on 8 Sep). Plots (2 x 25-ft row) were harvested on 5 Oct and individual treatments were weighed and graded. Maximum and minimum air temperature (oF) were 92.1 and 64.4 (Jun), 92.5 and 72.5 (Jul), 88.7 and 68.6 (Aug) and 91.3 and 64.8. Maximum and minimum soil temperature (oF) were 82.0 and 70.8 (Jun), 84.6 and 74.2 (Jul), 84.3 and 74.2 (Aug) and 82.3 and 69.3 (to 7 Sep). Precipitation was 0.32" (Jun), 1.14" (Jul), 0.41" (Aug) and 0.0" (to 7 Sep). Plots were irrigated to supplement precipitation to about 1"/A/4 day period with overhead sprinkler irrigation. Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 100% foliar infection by 7 Sep. From 50% emergence to harvest, 100 late blight disease severity values were accumulated (base 80% ambient relative humidity). Taking 38 days after inoculation [(DAI), 13 DAFA] as a key reference point, all fungicide programs reduced the foliar late blight significantly compared to the untreated control. Programs 1, 4, 5 and 10 had significantly greater foliar late blight than programs with less than 4.5% foliar late blight. All other programs were not significantly different from each other. Taking 42 DAI (17 DAFA)as a key reference point, there was almost complete defoliation of the untreated control due to late blight and all fungicide programs had significantly less foliar late blight than the untreated control. Program 4 had significantly greater foliar late blight than all other programs with 30.0% or less foliar late blight and program 10 with programs with 20.0% or less foliar late blight. Programs 1, 5, 6 and 9 were not significantly different from each other but programs 1 and 5 had significantly greater foliar late blight than programs with 11.5% or less foliar late blight All other programs were not significantly different from each other. All fungicide programs significantly reduced the average amount of foliar late blight over the season (RAUDPC, 0 to 42 DAI) compared to the untreated control. Application programs 4 and 10 had significantly higher RAUD PC values than all other programs with values below or equal to 1.99. Programs 1 and 5 had significantly higher RAUDPC values than program 3. Alternaria alternata was present throughout the season and programs 8 and 9 had significantly more A. alternata lesions than any other programs. Programs 6 and 11 had the lowest amount of A. alternata blight, significantly less than programs 1, 3, 7, 8, 9 and 10 but were not significantly different from any other programs. There were no significant differences in yield between any treatments. Phytotoxicity was not noted in any of the treatments. Funding: Industry Foliar late blight (%) 38 DAIz 13 DAFAb 42 DAI 17 DAFA RAUDPCx Yield (cwt/A) US1 Foliar Alternaria alternata (%) 17 DAFA 9.5 bcv 18.8 d 3.28 bc 31.3 bc 322 a 3.5 d 8.3 e 1.25 cd 13.8 de 337 a 2.8 d 7.5 e 1.03 d 25.0 bcd 310 a 38.8 b 4.89 b 12.5 de 332 a 20.0 d 3.45 bc 17.5 cde 334 a 3.0 d 4.0 d 4.5 d 12.0 de 10.8 e 11.5 e 1.59 cd 1.57 cd 1.59 cd 8.8 e 37.5 b 41.3 a 344 a 330 a 320 a Treatment and rate/A 1 KQ667 68.8WDG 1.0lb (A,C); Bravo WS 6SC 1.5pt (B) Curzate 60DF 0.21 lb + Bravo WS 6SC 1.0 pt (D,F,H) KQ667 68.8WDG 1.0lb + Curzate 60DF 0.21 lb (E,G,I)w ...... 2 KQ667 68.8WDG 1.5lb (A,C); Bravo WS 6SC 1.5pt (B) Curzate 60DF 0.21 lb + Bravo WS 6SC 1.0 pt (D,F,H) KQ667 68.8WDG 1.5lb + Curzate 60DF 0.21 lb (E,G,I)......... 3 KQ667 68.8WDG 2.0lb (A,C); Bravo WS 6SC 1.5pt (B) Curzate 60DF 0.21 lb + Bravo WS 6SC 1.0 pt (D,F,H) KQ667 68.8WDG 2.0lb + Curzate 60DF 0.21 lb (E,G,I)......... 4 KQ667 68.8WDG 1.5lb (A,C); Manzate 75WP 2.0 lb (B) Curzate 60DF 0.21 lb + Manzate 75WP 2.0 lb (D,F,H) KQ667 68.8WDG 1.5lb + Curzate 60DF 0.21 lb (E,G,I)......... 12.5 b 5 KP481 50WDG 0.31 lb + Manzate 75WP 1.0 lb (A,C) Bravo WS 6SC 1.5pt (B) Curzate 60DF 0.21 lb + Bravo WS 6SC 1.0 pt (D,F,G,H,I) KP481 50WDG 0.5 lb + Manzate 75WP 1.0 lb + Curzate 60DF 0.21 lb (E)......................................................... 10.0 b 6 Quadris 2.08SC 0.78 pt (A,C); Bravo WS 6SC 0.75pt (B) Curzate 60DF 0.21 lb + Bravo WS 6SC 1.0 pt (D,F,G,H,I) Curzate 60DF 0.21 lb + Quadris 2.08SC 0.78 pt (E)............... 7 Bravo WS 6SC 1.5 pt (A,B,C) Curzate 60DF 0.21 lb + Bravo WS 6SC 1.0 pt (D,E,F,G,H,I). 8 Manzate 75WP 1.5 lb (A,B); Quadris 2.08SC 0.39 pt (C) Curzate 60DF 0.21 lb + Equus ZN 6SC 1.5 pt (D,E,F,G,H,I).. 9 Manzate 75WP 1.5 lb (A,B); Quadris 2.08SC 0.39 pt (C) Equus ZN 6SC 1.5 pt + Super Tin 80WP 0.16 lb (D,E,F,G,H,I)………………………. 5.0 cd 10 Quadris 2.08SC 0.39 pt (A,C) Curzate 60DF 0.21 lb + Polyram 80DF 2.0 lb (B,D,E,F,G,H,I)……………………….. 11.3 b 11 KQ667 68.8WDG 1.5lb (A,B,C) 14.5 de 1.99 cd 55.0 a 367 a 30.0 c 4.32 b 27.5 bcd 355 a KQ667 68.8WDG 1.5lb + Curzate 60DF 0.21 lb (D,E,F,G,H,I)…………………………. 2.5 d 12 Untreated.................................................................................. 96.5 a z Days after inoculation with Phytophthora infestans, US8, A2. y Days after final application of fungicide. x RAUDPC, relative area under the disease progress curve calculated from day of inoculation to last evaluation of late blight. 0-42 DAI w Application dates: A= 23 Jun; B= 1 Jul; C= 8 Jul; D= 15 Jul; E= 22 Jul; F= 30 Jul; G= 7 Aug; H= 14 Aug; I= 21Aug. v Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). u No data as vines were defoliated by late blight. 1.28 cd 40.8 a 10.3 e 99.5 a 321 a 250 a 7.5 e ndu Funding: MPIC Summary Report for the 2001-2002 Dr. B. F. (Burt) Cargill Potato Demonstration Storage Brian Sackett, Chris Long, Dick Crawford, Todd Forbush (Techmark, Inc.), Steve Crooks, Greg Perkins, Tim Young, Jason Walther, Don Smucker (Montcalm CED) Troy Sackett, Randy Styma and Paul Main Introduction This is a summary report of the 2001-2002 Dr. B.F. (Burt) Cargill Potato Demonstration Storage Annual Report Volume 1. This report is design to provide a short summary of the 2001-2002 storage committee activities. To obtain a copy of the full 2001-2002 Demonstration Storage Report please contact the Michigan Potato Industry Commission office (517-669-8377) or Chris Long at Michigan State University. The full report will be provided to you free of charge. Summary and Highlights The 2001-2002 storage season marked a time for expansion of the objectives for the Storage and Handling Committee. Previously, the committee’s objective was to evaluate the storage protocols and storage management practices of commercial potato varieties utilized by Michigan growers. In the 2001-2002 storage season, the committee broadened their objectives by utilizing the storage performance of novel potato lines, from national breeding programs, as a selection criteria to evaluate the adaptability of new lines to the Michigan potato industry. Currently the Storage and Handling Committee’s objectives are twofold: 1.) to develop and evaluate storage techniques and provide storage recommendation for commercially available varieties and 2.) to evaluate promising new breeding material for its benefit to the Michigan potato industry through storage profile development. In order to effectively evaluate multiple breeding lines at one time, Bin #1 was converted to a box bin storage. Bin #1 can hold 20, 10 cwt. boxes which gives the committee the flexibility to develop storage profiles on 20 varieties at any one time. From the results from the box bin, three lines were selected to be grown in the bulk bins for the 2002-2003 storage season. Those lines are B0766-3, Liberator (MSA091-1) and W1201. The results of these storage profiles are described in the full report. This storage season marked the first time a variety developed at Michigan State University has reached a level for commercial processing. 550 cwt. of the breeding line MSF099-3 was processed at UTZ quality Foods on April 4, 2002. This line was stored in bulk bin #2. Overall, the variety performed well in storage in spite of some field frost prior to bin loading. As a result of its satisfactory performance, MSF099-3 was selected to be stored in a bulk bin in the 2002-2003 storage season. Bins #3 and #4 contained FL1879. Both bins performed very well into April with excellent chip quality.