MICHIGAN STATE UNIVERSITY AGRICULTURAL EXPERIMENT STATION IN COOPERATION WITH THE MICHIGAN POTATO INDUSTRY COMMISSION 2004 MICHIGAN POTATO RESEARCH REPORT Photo on Left Left to Right: Ben Kudwa, First Last, First Last, First Last, Senator Alan Cropsey, First Last, First Last Volume 36 TABLE OF CONTENTS PAGE INTRODUCTION AND ACKNOWLEDGMENTS……………………………. 1 2004 POTATO BREEDING AND GENETICS RESEARCH REPORT 2004 POTATO VARIETY EVALUATIONS David S. Douches, J. Coombs, K. Zarka, S. Copper, L. Frank, J. Driscoll and E. Estelle…………………………………………. 5 D. S. Douches, J. Coombs, L. Frank, J. Driscoll, J. Estelle, K. Zarka, R. Hammerschmidt, and W. Kirk…………………..….……...… 18 MANAGEMENT PROFILE FOR NEW POTATO VARIETIES AND LINES DECEMBER 2004 2004 ON-FARM POTATO VARIETY TRIALS Sieg S. Snapp, Chris M. Long, Dave S. Douches, and Kitty O’Neil…...….. 50 Chris Long, Dr. Dave Douches, Fred Springborn (Montcalm), Dave Glenn (Presque Isle) and Dr. Doo-Hong Min (Upper Peninsula)..…... 56 SEED TREATMENT, IN-FURROW AND SEED PLUS FOLIAR TREATMENTS FOR CONTROL OF POTATO STEM CANKER AND BLACK SCURF, 2004 W.W. Kirk and R.L. Schafer and D. Berry, P. Wharton and P. Tumbalam………………………………..……...…………..………..... 70 Chris Long and Dr. Willie Kirk……………..……...…………..……….... 73 POTATO SEED PIECE AND VARIETAL RESPONSE TO VARIABLE RATES OF GIBBRELLIC ACID 2003-2004 MANAGING RHIZOCTONIA DISEASES OF POTATO WITH OPTIMIZED FUNGICIDE APPLICATIONS AND VARIETAL SUSCEPTIBILITY; RESULTS FROM THE FIELD EXPERIMENTS. Devan R. Berry, William W. Kirk, Phillip S. Wharton, Robert L. Schafer, and Pavani G. Tumbalam………………….……….... 78 HOST PLANT RESISTANCE AND REDUCED RATES AND FREQUENCIES OF FUNGICIDE APPLICATION TO CONTROL POTATO BLIGHT (COOPERATIVE TRIAL QUAD STATE GROUP 2004) W.W. Kirk, F. Abu El-Samen, D.S. Douches, C. Thill, J. Jang and A. Thompson……………………...….………………………………....... 98 PAGE EVALUATION OF TUBER LATE BLIGHT RESPONSE OF POTATO CULTIVARS AND ADVANCED BREEDING LINES AND THEIR POTENTIAL TO REDUCE SEED-BORNE EPIDEMICS OF LATE BLIGHT MICHIGAN STATE UNIVERSITY 2003-2004 Dr. Willie Kirk, Dr. Firas Abu El-Samen, Dr. Ray Hammerschmidt, and Dr. Dave Douches……………….……………………...….………... 104 EVALUATION OF FUNGICIDE PROGRAMS FOR POTATO LATE BLIGHT CONTROL, 2004 W.W. Kirk and R.L. Schafer and D. Berry, P. Wharton and P. Tumbalam………………………………..……...…………..……….. 118 George W. Bird…………………………………………………………. 127 MICHIGAN POTATO INDUSTRY COMMISSION 2004 NEMATOLOGY ANNUAL REPORT POTATO INSECT BIOLOGY AND MANAGEMENT Edward J. Grafius, Walter L. Pett, Beth A. Bishop, Adam M. Byrne, and Eric N. Bramble…………………………………. 142 POTATO VINE DESICCATION STUDY Christy Sprague and Gary Powell……...……………………….………. 156 SUMMARY REPORT FOR THE 2003-2004 DR. B.F. (BURT) CARGILL POTATO DEMONSTRATION STORAGE Brian Sackett, Chris Long, Dick Crawford, Todd Forbush (Techmark, Inc.), Steve Crooks, Dennis Iott, Keith Tinsey, Tim Young, Jason Walther, Troy Sackett, Randy Styma, and Ben Kudwa….……………………………………………………… 160 2004 MICHIGAN POTATO RESEARCH REPORT C. M. Long, Coordinator INTRODUCTION AND ACKNOWLEDGMENTS The 2004 Potato Research Report contains reports of the many potato research projects conducted by MSU potato researchers at several locations. The 2004 report is the 36th volume, 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. We also want to recognize Barb Smith and Lori Olin at MPIC for helping with the details of this final draft. WEATHER The overall 6-month average temperatures during the 2004 growing season were very similar to the 6-month average for the 2003 season, and were near the 15-year average (Table 1). There were no recorded temperature readings of 90 °F or above in 2004. There were 7 days in April and 2 in early May that the temperature was below 32 °F. The first daytime low, near 32 °F, during harvest occurred on September 30 with a recorded reading of 32.6 °F. There were four day time lows at or below 32 °F in October. The average maximum temperatures for July and August of 2004 were similar to the 15-year average (Table 1), but the average maximum temperature in September was 7 degrees warmer than the 15-year average. Rainfall for April through September was 17.13 inches (Table 2). Rainfall recorded during the month of May was the highest recorded for that month in 15 years. Rainfall recorded during the month of September was the lowest recorded for that month in 15 years. Irrigation at MRF was applied 13 times from June 29th to August 30th averaging 0.70 inches for each application. The total amount of irrigation water applied during this time period was 9.05 inches. 1 Table 1. The 15-year summary of average maximum and minimum temperatures (°F) during the growing season at the Montcalm Research Farm. July May June April August September 6-Month Average Year Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. 47 NA NA 1990 52 47 1991 46 46 1992 1993 46 50 50 51 1994 51 45 1995 1996 51 50 48 50 1997 52 52 1998 1999 48 51 50 49 2000 53 48 2001 51 52 2002 2003 48 49 49 49 2004 NA NA 64 71 60 70 51 54 68 66 57 66 51 50 64 59 54 75 60 59 71 70 56 70 61 63 56 56 64 67 62 43 47 42 45 43 45 44 39 51 48 49 49 42 44 46 79 81 76 81 79 82 76 80 82 84 77 83 85 81 79 57 57 51 60 55 65 59 55 60 56 57 70 58 58 53 77 82 76 74 78 81 75 79 77 77 75 78 79 77 74 55 59 50 55 55 57 57 56 56 55 57 57 58 52 54 58 60 54 61 60 60 55 57 58 62 56 58 62 58 57 58 78 80 75 79 75 82 80 73 81 76 79 72 81 82 76 78 72 69 69 64 73 70 70 69 76 73 70 69 77 72 78 71 40 34 33 34 31 31 31 37 37 34 37 36 33 37 35 74 70 70 71 72 69 69 75 73 71 72 73 72 73 72 15-Year Average 56 Table 2. 67 45 77 56 80 58 49 50 The 15-year summary of precipitation (inches per month) recorded during the growing season at the Montcalm Research Farm. Year 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 15-Year Average April 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 0.70 1.79 2.99 May 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 8.18 4.00 June 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 1.85 3.13 3.63 July 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 2.60 1.72 3.41 August September 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 2.60 1.99 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 2.06 0.32 4.32 2.69 Total 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 13.25 17.13 21.32 2 GROWING DEGREE DAYS Table 3 summarizes the cumulative, base 50°F growing degree days (GDD) for May through September, 2004. The total GDD for 2004 were 2,060 which is 196 GDD fewer than 2003, and second lowest in the 10-year average. Table 3. Growing Degree Days* - Base 50°F. Cumulative Monthly Totals Year 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 10-Year Average May 202 201 110 427 317 313 317 319 330 245 278 June 779 681 635 932 865 780 808 903 762 662 781 July 1421 1177 1211 1545 1573 1301 1441 1646 1302 1200 1382 August September 2136 1776 1637 2180 2070 1851 2079 2214 1922 1639 2348 2116 1956 2616 2401 2256 2379 2613 2256 2060 1950 2300 *1995-2004 data from the weather station at MSU Montcalm Research Farm (Michigan Automated Weather Network system Entrican, MI.) 3 PREVIOUS CROPS, SOIL TESTS AND FERTILIZERS The general potato research area utilized in 2004 was rented from Steve Comden, directly to the West of the Montcalm Research Farm. This acreage was planted to field corn in the spring of 2003, harvested in the fall and the stubble was disked under. In the spring of 2004, the recommended rate of potash was applied and disked into the corn stubble. The ground was moldboard plowed for direct potato planting. The area was not fumigated prior to potato planting. Potato early die symptoms in 2004 were believed to have been the result of the leaching of starter fertilizer due to the heavy rainfall in the month of May and not necessarily related to components of the early die complex. The soil test analysis for the general crop area was as follows: lbs/A P2O5 K2O Ca Mg pH 6.0 372 (186 ppm) 174 (87 ppm) 790 (395 ppm) 122 (61 ppm) 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 46-0-0 250 lbs/A 19 gpa 135 lbs/A 197 lbs/A 197 lbs/A 0-0-150 40-36-0 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 at 0.66 lb/A and Dual at 1.33 pints/A. Admire was applied at planting at a rate of 13.6 oz/A. Dimetholate was applied once in mid June at 1 pint/A. Fungicides used were Bravo and Manzate over 13 applications. Potato vines were desiccated with Reglone in late August and again in early September at a rate of 1 pint/A. 4 Estelle Department of Crop and Soil Sciences Michigan State University East Lansing, MI 48824 2004 POTATO BREEDING AND GENETICS RESEARCH REPORT David S. Douches, J. Coombs, K. Zarka, S. Cooper, L. Frank, J. Driscoll, and E. Cooperators: R.W. Chase, Ray Hammerschmidt, Ed Grafius Willie Kirk, George Bird, Sieg Snapp and Chris Long INTRODUCTION At Michigan State University we are breeding potatoes for the chip-processing and tablestock markets. The program is one of four integrated breeding program in the North Central region. At MSU, we conduct a multi-disciplinary program for potato breeding and variety development that integrates traditional and biotechnological approaches. In Michigan, it requires that we develop high yielding round white potatoes with excellent chip-processing from the field and/or storage. 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 13 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. The breeding goals at MSU are based upon current and future needs of the Michigan Over the years, key infrastructure changes have been established for the breeding program to make sound assessments of the breeding material moving through the 5 Each year, during the winter months, 500-1000 crosses are made using about 150 of program. These include the establishment and expansion of the scab nursery, the development of the Muck Soils Research Farm for late blight testing, the incorporation of no-choice caged studies for Colorado potato beetle assessment and the Michigan Potato Industry Commission (MPIC)-funded construction of the B.F. (Burt) Cargill Demonstration Storage adjacent to the Montcalm Research Farm. PROCEDURE I. Varietal Development the most promising cultivars and advanced breeding lines. The parents are chosen on the 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, 20-hill and 30-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 (42-48°F) and/or 50˚F storage. In addition, Chris Long evaluates the more advanced selections in the 10 cwt box bins and manages the 500 cwt. storage bins which may have MSU lines. III. Germplasm Enhancement "diploid" (2x = 24 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, late blight resistance, verticillium wilt resistance), S. With the Demonstration Storage facility adjacent to the Montcalm Research Farm To supplement the genetic base of the varietal breeding program, we have a 6 Integration of Genetic Engineering with Potato Breeding 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 12 years experience in Agrobacterium-mediated transformation to introduce genes into important potato cultivars and advanced breeding lines. We are presently using genes in vector constructs that confer resistance to Colorado potato beetle and potato tuber moth (Bt- cry3A, Bt-cry1Ia1 and avidin), potato tuber moth, late blight resistance via the RB gene, lowering glycoalkaloids (STG), and drought resistance (CBF1). 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 need for a selectable marker (antibiotic resistance) from the production of transgenic plants. RESULTS AND DISCUSSION I. Varietal Development Breeding 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 2004 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 as part of the Quad state cooperative effort. During the 2004 harvest, 1055 selections were made from the 40,000 seedlings produced. 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 2004 directly out of 42°F and 50°F storages. 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, 220 and 90 selections were made, respectively. Table 1 lists some of the potential lines for grower trials in year 2005. 7 Dr. Joe Sowokinos, Univ. of Minnesota, has conducted biochemical analyses of Efforts have been made to identify lines with good appearance, low internal defects, About 60% of the single hill selections have a chip-processing parent in their Chip-Processing pedigree. Of those selections chipped out of the field, about 85% have a SFA chip score of 1.5 or less. Based upon the pedigrees of the parents we have identified for breeding cold-chipping potato varieties, there is a diverse genetic base. We have at least eight cultivated sources of cold-chipping. Examination of pedigrees shows up to three different cold-chipping germplasm sources have been combined in these selections. Our promising chip-processing lines are MSG227-2 (scab resistant 45°F chipper), MSH095-4, MSJ036-A (scab resistant), MSH228-6 (moderate scab resistance), MSJ147-1, MSJ126- 9Y (moderate scab resistance), MSJ316-A (moderate scab resistance), MSK061-4 (moderate scab resistance) and late blight resistant chipper MSJ461-1. our best chipping lines and has discovered that our lines differ from older varieties in their proteins (UGPase) involved in chipping. Some of these lines are MSJ147-1, MSG227-2 and MSJ126-9Y. Moreover, MSJ147-1 and MSJ126-9Y have the desirable levels of acid invertase to chip process from colder storage. His analysis will also allow us target specific crosses to find improved chip-processing varieties that will allow processing from colder storage temperatures. Tablestock good cooking quality, high marketable yield and resistance to scab and late blight. 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 and yellow-fleshed lines. From our breeding 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 2004, while others were tested under replicated conditions at the Montcalm Research Farm. Promising tablestock lines include MSE221-1 as a scab resistant tablestock, MSI049-A, a bruise resistant round white with red splashes around the eyes, and N084-11, a round white with a smooth round shape and bright skin. We have a number of tablestock selections with late blight resistance. These are MSK128-A, MSL006-AY, MSL072-C, MSL179-AY, MSM171-A and MSM224-1. MSL211-3 has late blight and scab resistance. In addition, all these clones performed well in the dry land trial at Montcalm Research Farm such as Boulder and Michigan Purple and MSJ461-1. MSE192-8RUS and MSA8254-2BRUS are two russet table selections that have scab resistance, while MSL794-BRUS has late blight resistance. MSI005-20Y and MSJ033-10Y are yellow-fleshed lines with smooth round appearance and high yield potential. sale of Michigan Purple and Jacqueline Seed to the roadside stand and farm market operations. At the Great Lakes Expo the MPIC sponsored a booth where we helped promote the 8 Disease and Insect Resistance Breeding Disease screening for scab has been an on-going process since 1988. Results from the 2004 MSU scab nursery indicate that 53 of 158 lines evaluated demonstrated little to no infection to common scab. In addition, 19 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. In 2004, we expanded the scab nursery with an additional acre of land nearby. For three years we inoculated the field with Streptomyces scabies and grew scab susceptible cultivars. After 2003 we determined that the infection level was high enough to use for research. This expansion has allowed us to conduct early generation selection for scab resistance among our breeding material. We hope that this expanded effort will lead to more scab resistant lines advancing through the breeding program. In the mid-1990’s late blight re-emerged as the major fungal disease of potato in the US. Dr. Willie Kirk established foliar late blight testing at the Muck Soils Research Farm, Bath, Michigan. This location has become an excellent North American site for late blight testing because of the humid microclimate and isolation from major commercial potato production. As a result, late blight infection has been consistently achieved each year making breeding efforts to select late blight resistant germplasm very efficient. The breeding program has been able to identify advanced breeding lines with strong foliar resistance to late blight. In 2001 we released Jacqueline Lee, a yellow-fleshed tablestock potato with late blight resistance. We also have the late blight resistant lines MSI152-A and MSJ317-1, round white tablestock potatoes, and MSJ461-1, a round white chip- processor, being considered for release and commercialization. MSJ461-1, the chip- processing selection, has the same late blight resistance source Jacqueline Lee and was resistant to a US-17 genotype of Phytophthora infestans in New York this year. Our other promising late blight resistant lines that have been tested in replicated agronomic trials are MSJ317-1, MSI152-A, MSK136-2, MSL179-AY and MSL211-3 (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. The Muck Soils Research Farm is also used for early generation selection for late blight, genetic studies involving late blight resistance, screening germplasm from other US breeding programs and Dr. Kirk-led fungicide x variety management studies to determine schemes to reduce fungicide usage when late blight resistant cultivars are grown. In 2004 we also screened our RB-transgenic potatoes for their foliar resistance to late blight. With support from GREEEN, we also introduced an early generation Colorado potato beetle screen at the Montcalm Research Farm. In 2004 over 220 breeding lines 9 from the MSU potato breeding program that had Colorado potato beetle resistant germplasm in their pedigree were evaluated at the Montcalm Research Farm Beetle Nursery. The beetle pressure was extremely high leading to complete defoliation in all susceptible check lines. Percent defoliation was visually estimated during the beetle infestation in June and July. The lines were then sorted into four categories: susceptible, reduced susceptibility, moderately resistant and resistant. The majority of the lines were susceptible, but 32, 32 and 26 lines were classified as reduced susceptibility, moderately resistant and resistant, respectively. The majority of the lines that were moderately resistant or resistant can be attributed to the expression of the Bt-cry3A gene or glycoalkaloid/leptine based mechanisms. The most resistant material was selected for further advancement in the breeding program and also for use in the next round of crossing to develop beetle resistant cultivars. Concurrently, a field cage (no-choice) experiment was conducted to evaluate 6 lines. With two years of data, the glandular trichome-based resistance was not different from the susceptible cultivar. The Bt-based resistance was very effective with complete mortality. The glycoalkaloid-based resistance affected beetle behavior: clipping of the petioles was observed in the cages. Avidin-based insect resistance is being studied in the lab. This resistance may be useful in combination with other host plant resistance factors. It is a great challenge to achieve host plant resistance in a commercially acceptable line. We have some promising advanced selections with partial resistance to Colorado potato beetle. In addition, we have Bt-cry3A transgenic lines that could be commercialized if the processors renewed their acceptance and regulatory environment was modified to reduce costs. II. Evaluation of Advanced Selections for Extended Storage: MSU Potato Breeding Chip-processing Results From the MPIC Demonstration Commercial Storage (October 2003 - June 2004) 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 5 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 2003, tuber samples from 4 MSU lines plus three Frito Lay lines and Snowden in the Montcalm Research Farm trials were placed in the bin to be cooled to 49°F. Tubers from another 5 lines were placed in the bin that was to be cooled then held at 54°F. The first samples were chip-processed at MSU in October and then, each month until April 2004. Samples were evaluated for chip-processing color and quality. Table 2 summarizes the chip-processing color of select lines over the 6-month storage season. In the 49°F bin, Snowden was the check variety. From October to April all lines chip-processed acceptably. In the 54°F bin Atlantic was used as check varieties and chip-processed acceptably until April. Liberator, MSH228-6 and MSJ461-1 also chip-processed acceptably. Only MSH112-6 did not chip-process and was dropped from the program. MSG227, UEC, and Liberator were in the 500 cwt storage bins. See Chris Long’s storage report for those results and results from the box bins. 10 In 2004, about 3% of the populations evaluated as single hills were diploid. From III. Germplasm Enhancement this breeding cycle, we plan to screen the selections chip-processing from storage. In addition, selections were made from over 4,000 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 50 selections were made among the diploid material in 2004. 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 continue conducting extensive field screening for resistance to Colorado potato beetle at the Montcalm Research Farm and at the Michigan State University Horticulture Farm in 2005. In 2004 we made crosses with late blight resistant diploid lines derived from Solanum microdontum to our tetraploid lines. These progeny are being grown in the greenhouse and will be evaluated in 2005 for these late blight resistant and other agronomic characteristics. IV. Integration of Genetic Engineering with Potato Breeding 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, is the leading insect pest of potato (S. 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 2003 and 2004 to compare natural (glandular trichomes (NYL235-4) and glycoalkaloid-based (ND5822C-7)), engineered (Bt-cry3A: NO8.8, Atlantic NewLeaf, Bt-cry1Ia1: Spunta G2) host plant resistance mechanisms of potato for control of Colorado potato beetle. Six different potato lines representing 5 different host plant resistance lines 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. Twenty egg masses were placed on the plants in each cage. 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 line and the combined resistance line were effective in controlling feeding by Colorado potato beetle adults and larvae. 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. Spunta G2 was effective in limiting defoliation, but larval mortality was not as high as in the Bt-cry3a lines. Based on these results, the Bt-cry3A gene in combination with glandular trichome mechanism 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. The Bt- cry1Ia1 all is effective against Colorado potato beetle. Figure 1 shows the combined results of caged trial in 2003 and 2004. 11 Combining engineered and natural host plant resistance to Phytophthora infestans in cultivated potato General susceptibility of potato cultivars to Phytophthora infestans (Mont.) de Bary is a major concern for potato production. The major resistance gene RB was cloned from Solanum bulbocastanum Dun. a diploid (2n=2x=24) Mexican species that is highly resistant to all known races of P. infestans. The objective of this work is to combine conventionally bred sources of resistance with the RB gene via Agrobacterium transformation. Our hypothesis is that by pyramiding engineered resistance with natural plant resistance we expect to obtain stronger and more durable resistance to potato late blight. Therefore, this study was undertaken to test the effectiveness of the RB gene on its own by transforming late blight-susceptible clones (Atlantic, and the breeding line MSE149-5Y), and to test the effectiveness of the gene in combination with natural late blight resistance by transforming resistant clones (Stirling, and the advanced breeding line MSJ461-1). The RB-transgenic potato lines were tested at the Muck Soils Research Farm and we identified 3 lines to be expressing the RB gene and have foliar late blight resistance. Insecticidal activity of avidin against Colorado potato beetle larvae, Leptinotarsa decemlineata (Say) The Colorado potato beetle, Leptinotarsa decemlineata (Say), is the most destructive insect pest of potato, Solanum tuberosum (L.) in eastern North America. The insect has adapted to every insecticide used to manage it. Avidin is a protein found in chicken egg whites that has demonstrated insecticidal properties against a number of Lepidopteran and Coleopteran pests. This protein protects the chicken embryo by sequestering biotin from disease causing organisms. Biotin is an essential co-enzyme required for all organisms, including insects. Biotin is a cofactor of a carboxylase which is required for many important processes like lipogenesis, gluconeogensis, fatty acid and amino acid catabolism. Without this co-enzyme, an insect’s growth is severely stunted, eventually leading to death. The gene for avidin production has been cloned and inserted into a few crops, including maize, tobacco and potato and has demonstrated resistance to a wide spectrum of insect pests. We have expressed avidin in two potato lines: MSE149-5Y, a susceptible potato line, and ND5873-15, a high glycolakaloid line. Detached leaf bioassays were performed on transgenic and non-transgenic clones of MSE149-5Y and ND5873-15 using Colorado potato beetle neonates and third instars. Survivorship and consumption were measured every 2d over a 12d period for neonates and avidin was effective in reducing growth and increasing larval morality. USAID-funded International project to Develop Potato Tuber Moth Resistant Potatoes 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 12 Variety Release V. countries in the Middle East, is the potato tuber moth. Recently it has emerged as a pest in Washington State and has also been a serious problem in Mexico. Two transgenic 'Spunta' clones, G2 and G3, have been identified that produced high control levels of mortality in first instars of potato tuber moth in 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'. In 2004 the Spunta lines were resistant to the potato tuber moth and the Colorado potato beetle in Washington State. We are currently working with USAID, Syngenta and South Africa to commercialize the Spunta-G2 and Spunta-G3 lines. We have also transformed Atlantic, Lady Rosetta and Jacqueline Lee with the Bt-cry1Ia1 (formally cryV gene). We will be naming, releasing and protecting UEC in 2005. MSG227-2 (scab resistant chipper) and MSJ461-1 (late blight resistant chipper/tablestock) also show commercial potential. Table 3 summarizes the commercial seed production of MSU lines in 2004. VI. Development of a DNA-based Fingerprint System for Potato Varieties The ability to quickly and accurately identify potato clones is important to potato breeding programs and to the potato seed industry and commercial growers. Since 1990, the Michigan State University Potato Breeding and Genetics Program has used an isozyme-based fingerprint system to identify potato cultivars. Isozyme analysis has been an economical and effective means of discriminating potato clones; however, they require fresh, healthy tuber or leaf tissue. DNA-based fingerprinting using simple sequence repeats (SSRs or microsatellites) has been shown to discriminate between potato clones. DNA can be extracted from freeze-dried tissue. The SSR fingerprinting system developed in our lab can be used as a practical fingerprint system for cultivated potato. This research was published in the American Journal of Potato Research in 2004. 13 Table 1. Potential Lines for 2005 On-Farm Grower Trials Female Pedigree Male Comments MSC127-3 Prestile OP MSC127-3 Zarevo A7961-1 S440 MSC148-A S440 Norvalley Pike B0718-3 NY88 Tollocan ND2676-10 MSC148-A Greta B0718-3 Saginaw Gold Brodick Scab resistant Scab tolerant Scab tolerant chipper High yield cold chipper Scab tolerant chipper Late blight resistant Scab tolerant chipper Late blight resistant Scab tolerant chipper Line Processing MSG227-2 MSH228-6 MSJ036-A MSJ080-1 MSJ147-1 MSJ316-A MSJ461-1 MSK061-4 MSK136-2 MSK498-1Y Tablestock W870 BOULDER (MSF373-8) MS702-80 LIBERATOR (MSA091-1) MS702-80 MICHIGAN PURPLE MSA8254-2BRUS MSE192-8RUS MSE221-1 MSI005-20Y MSI049-A MSI152-A MSJ033-10Y A8163-8 Superior MSA097-1Y Penta Brodick Mainestay MSA097-1 MSC121-7 B0718-3 Penta NY88 Norchip Maris Piper Dryland production, large tubers Scab resistant, bright skin Bright purple skin, white flesh Scab tolerant Russet Norkotah Scab resistant russet (Norkotah replacement) MS700-83 Scab tolerant, Superior-type Yukon appearance Blackspot bruise resistant, red splashes Late blight resistant, round white Yellow, Scab resistant 14 Table 2. 2003-2004 Demonstration Storage Chip Results Michigan State University Potato Breeding and Genetics Montcalm Research Farm Chip Scores: SFA Scale† Date: 11/4/2003 12/2/2003 1/6/2004 2/12/2004 3/11/2004 4/7/2004 Sample Dates: Line Temp: 55 °F 54 °F 50 °F 50 °F 49 °F 51 °F FL1833 FL1867 FL1922 MSG227-2 MSJ080-1 MSJ147-1 SNOWDEN UEC ATLANTIC LIBERATOR MSH112-6 MSH228-6 MSJ461-1 1.5 1.0 1.0 1.0 1.0 1.0 ND 1.0 1.0 1.0 1.0 1.5 1.5 1.0 1.0 1.0 1.5 1.0 1.0 1.5 1.5 1.5 1.0 1.0 1.5 1.0 1.0 1.0 1.5 1.0 1.0 1.0 ND 1.5 1.0 1.0 1.5 1.0 1.0 1.0 ND 1.0 1.0 1.0 1.5 1.5 1.5 1.5 Temp: 55 °F 54 °F 54 °F 54 °F 54 °F 51 °F 1.5 1.5 2.0 1.0 1.5 1.0 1.0 2.5 1.0 2.0 1.5 1.0 2.0 1.5 1.5 1.5 1.0 2.0 1.0 1.0 1.5 1.0 2.0 1.5 1.5 1.5 1.0 1.0 1.5 1.5 †Snack Food Association Chip Score Ratings: 1 - 5 1: Excellent 5: Poor ND: No Data Chip scores were from two-slice samples from five tubers of each line collected at each sample date. 15 Table 3. Potato Seed Inventory 2004 MSU Potato Breeding Program Introductions Availability of Michigan Certified Seed A Cumulative Inventory LINE Jacqueline Lee (MSG274-3) Liberator (MSA091-1) Michigan Purple MSE192-8RUS MSE202-3RUS MSF099-3 MSG227-2 MSH067-3 MSH095-4 MSI152-A MSJ461-1 MINI- TUBERS (UNITS) FY1 (CWT) FY2 (CWT) FY3 (CWT) FY4 (CWT) 7901 5153 4986 3247 635 - 388 573 617 2280 7274 3 27 106 - - - - - - 5 4 - 748 1422 - - - - - - - 88 100 4150 - - - 67 1950 - - - - 1080 - - - - - - - - - - Information listed above is a cumulative count from Golden Seed Farms, Haindl & Hanson Farms, Iott Seed Farms Inc., Krueger Seed Farm, Marker Farms, Makarewicz Seed Farm, Sklarczyk Seed Farm, and Skogman Seed. Table courtesy of Chris Long. 16 Fig. 1 Colorado Potato Beetle Field Cage Trial Relative Area Under the Defoliation Curve (RAUDC) of HPR Potato Lines 0 0 1 x C D U A R 40 35 30 25 20 15 10 5 0 31 a 29 a 16 b 13 b 23a 22 ab 2003 LSD0.05 = 23.3 2004 LSD0.05 = 6.2 2003 2004 14 ab 6 c Atlantic L235-4 ND5822C-7 Spunta G2 NO8.8 Atlantic Newleaf HPR Potato Line 0.3 b 0.2 c 0.2 b 0.13 c 17 Funding: Fed. Grant/MPIC 2004 POTATO VARIETY EVALUATIONS D.S. Douches, J. Coombs, L. Frank, J. Driscoll, J. Estelle, 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 INTRODUCTION Each year we conduct a series of variety trials to assess advanced potato selections from the Michigan State University and other potato breeding programs at the Montcalm Research Farm. The evaluation also includes disease evaluation in the scab nursery and foliar and tuber late blight evaluation at the Muck Soils Research Farm. 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, and blackspot bruising are determined. PROCEDURE Eleven field experiments were conducted at the Montcalm Research Farm in Entrican, MI. They were planted as randomized complete block designs with two to 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. The field experiments were conducted on new potato ground that was in corn the previous year. harvested at two dates (Date-of-Harvest trial: Early and Late). The other field experiments were the Russet, North Central Regional, Adaptation (tablestock and chip-processors), and Preliminary (tablestock and chip-processors), Transgenic and two water management 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 45°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 18 RESULTS A. Round White Varieties: Chip-processors (Tables 1 and 2) There were 20 entries that were compared at two harvest dates. Atlantic, Snowden and four Frito Lay clones were used as checks. The plot yields were below average in the early harvest (100 days), but specific gravity values were very high due to the cool summer temperatures in July and August. Most lines increased between 30-70 cwt/a in yield for the second harvest date (140 days). We attribute the lower yields to the loss of fertilizer from the heavy spring rains. The results are summarized in Tables 1 and 2. Hollow heart and vascular discoloration were the prevalent internal defects. Note that this year we changed the format of the data table so that the internal defects are presented as percentages rather than as a count. Atlantic, Boulder, MSH067-3 and UEC showed the highest incidence of hollow heart between the two harvest dates. Vascular discoloration was only frequent in the later harvest, with MSH095-4 and Snowden being the highest. In the early harvest trial, the best yielding chipping lines were Atlantic, MSH112-6, and MSJ147-1. We have dropped MSH112-6 because it has poor chipping quality. MSJ147-1 is showing promise as a chipper out of colder storage temperatures and tissue culture plants have been distributed to the industry for larger scale testing. In the later harvest, MSJ147-1 has been consistently in the top group for the past few years. MSJ461-1, Boulder and MSF099-3 also yielded well, but Boulder had an abundance of off- types and hollow heart for the first time in 2004. MSJ461-1 is a promising chip-processing line with strong foliar resistance to late blight. MSF099-3 is dropped because of scab susceptibility. Liberator, MSG227-2 and FL1922 offer scab resistance. UEC, Liberator, MSJ461-1 and MSG227-2 are in the 500 cwt bins of the Commercial Demonstration Storage this year. Tablestock (Tables 1 and 2) Only two tablestock clones were tested in the Date of Harvest Trials in 2004. The russets are in a separate trial and the reds, along with other round whites and yellows are found in the North Central and Adaptation trials. The descriptions of Michigan Purple and Jacqueline Lee are below. Variety Characteristics specific gravity over the past 7 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 2003 and 2004 Commercial Demonstration Storage. UEC – an unknown eastern chip processing line thought to be from USDA-Beltsville. It has high yield potential and scab tolerance along with excellent chip-processing quality. It is in the 500 cwt 2002, 2003 and 2004 Commercial Demonstration Storage bins. It is being considered for naming and release in 2005. 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 LIBERATOR - a MSU selection for chip-processing with strong scab resistance. Yield and 19 The russet trial had 21 lines evaluated in 2004. GoldRush and Russet Burbank and Russet well from the 42°F MPIC demonstration storage studies. It has yielded well in some on-farm trials. It is in the 2004 500 cwt storage bins. This line will be considered for release in 2006. MSJ147-1 – a full season storage chipper that also has some early sizing. It has excellent chip- processing quality and a large percentage of A-size tubers. It has performed well in on-farm trials. MSH228-6 – a chip-processing line with moderate scab resistance. It has a good type and has performed well in on-farm trials. MSH095-4 - a mid-season maturing line with excellent chip quality and bruise susceptibility equal to Snowden. It had not yielded well in the past few years at Montcalm Research Farm or the on-farm trials. It is intermediate in scab tolerance between Atlantic and MSG227-2. MSJ461-1 – an 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 above average yield, but an intermediate specific gravity in most years. The chips show few defects. It is in the 2004 500 cwt storage bins. It has good tablestock quality too. 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. Do not let the tubers oversize. A thin skin makes this variety a challenge market on a large scale without making adjustments in harvest, washing and grading process. We regard this as a variety that can compete in the red market. It has great potential in the roadside stand and farm markets. 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. It is our best tasting potato! The strength of this selection is also its strong foliar resistance to the US8 genotype of late blight. Vine maturity is similar to Snowden. There is interest in California to market this variety. It has great potential in the roadside stand and farm markets. C. Russet Varieties (Table 3) Norkotah were the standard varieties in the trial and the results are summarized in Table 3. Scab resistance was prevalent among the lines tested. Internal quality was high except for vascular discoloration in Keystone Russet. Specific gravity measurements were above average with Russet Burbank and GoldRush having 1.084 and 1.076 readings. The yield of the overall trial was below average for 2004. Off type and cull tubers were found in all lines tested, but the frequency was generally low in 2004. In general, the highest yielding lines also had the latest vine maturity in the trials. Gemstar, Keystone Russet and Silverton Russet show the most promise, however, the varietal choice should take into account whether a new variety is a symptomless carrier of PVY. MSA8254- 2BRUS is a high yielding MSU selection that has yielded well in on-farm trials. MSL794-BRUS had foliar late blight resistance, but did not exhibit strong resistance to scab. Stampede Russet has a JACQUELINE LEE – an MSU oval/oblong tablestock selection with a high tuber set. The 20 The North Central Trial is conducted in a wide range of environments (11 locations) to provide very attractive type, but has a low yield. MSE192-8RUS has similar features. Millenium Russet was the most blackspot bruise susceptible line tested in the trial. D. North Central Regional Trial (Table 4) adaptability data for the release of new varieties from North Dakota, Minnesota, Wisconsin, Michigan and Canada. Twenty-three breeding lines and 7 check varieties were tested in Michigan. The results are presented in Table 4. The range of yield was very wide (412 cwt – 61 cwt) which is typical for this trial each year. Moreover, the yields were below average this year, while the specific gravity readings were very high. This year we sorted the table into round white, reds and russet sections. This grouping will allow more meaningful comparisons to be made when looking at the table. The MSU lines MSJ317-1, MSI152-A, MSH095-4 and MSH031-5 were the Michigan representatives included in the North Central Trial. Both MSJ317-1 and MSI152-A round white tablestock selections have nice type and both have foliar late blight resistance. We are dropping MSH031-5 and will continue to evaluate MSH095-4. The chipper W1773-7 shows high yield potential, while FV12486-2 and CV89023-2R have excellent red color. Gemstar and V1102-1 were the best-performing russet lines. E. Adaptation Trial (Tables 5A and 5B) (Snowden, Pike and Atlantic) and 25 advanced breeding lines are reported in the chip-processing trial. The trial was harvested after 140 days and the results are summarized in Table 5A. As in 2003, MSJ036-A was the highest yielding line. It also has a high specific gravity reading and scab resistance. The tuber type of MSJ036-A is also round and attractive. Other lines in the trial that show promise are MSK128-A and MSK136-2 which have foliar late blight resistance. MSM051-3, MSK061-4, MSK476-1 and MSJ126-9Y offer scab resistance with chip-processing from the MSU program. W2128-8 also showed scab resistance in 2004. The Cornell University line NY126 is a yellow-fleshed line with good type. breeding lines and new varieties are summarized in the table. The trial was harvested after 133 days and the results are summarized in Table 5B. Two red-skinned entries were tested. Dakota Jewel did not yield well in 2004, but the type and red color are attractive. Keuka Gold, a light yellow fleshed variety (NY101) from Cornell University was the highest yielding line. There are a number of promising late blight resistant lines to note: MSM224-1, MSL072-C, MSM171-A, MSM137-2, MSM183-1Y and MSL211-3. MSI049-A was the high yielding line and was also a strong performing line in the dry land trial with blackspot bruise resistance and moderate late blight resistance. MSK136-2 is a round white selection with chip-processing and strong foliar resistance to late blight. MSI005-20Y and MSJ033-10Y are scab tolerant yellow-fleshed selections that shows promise. F. Preliminary Trial (Tables 6A and 6B) The Adaptation trial was divided into chip-processing and tablestock trials. Three cultivars In the tablestock trial Onaway and Yukon Gold were the check varieties and 18 advanced 21 The Preliminary trial is the first replicated trial for evaluating new advanced selections from the MSU potato breeding program. The division of the trials was based upon chip-processing and tablestock utilization. Thirty-one advanced selections and three check varieties were reported chip- processing Preliminary trial. The chip-processing trial is summarized in Table 6A was harvested after 133 days. Most lines chip-processed well from the field. Specific gravities were high, but yield was below average. The top yielding line was MSN251-1Y, a yellow-fleshed line with scab resistance, but is late maturing. Another promising line is MSN105-1 which has both scab and late blight resistance. MSM185-1 has scab resistance and some moderate resistance to the Colorado potato beetle. MSN144-2 has some scab tolerance and high yield potential. Table 8B summarizes the tablestock lines. Interestingly, many have foliar late blight resistance. This trial was also harvested and evaluated after 133 days. Nine of the 17 lines were late blight resistant. Despite the late blight resistance, the vine maturities were not late in all cases. Seven different late blight resistance sources were also represented. The most promising lines combining tablestock qualities and late blight resistance are MSL179-AY, MSN228-5, MSL183-AY and MSM417-A. MSL179- AY also stood out in the 2003 trial. MSN188-1 is selection with purple splashes that may suit the roadside markets. NDMS7994-1RUS is a scab resistant russet selection to test further. MSN084-3 is a selection with bright, round tubers. It is a cross between Boulder and Chaleur. G. Trangenic Trial (Table 7) A field trial was conducted to evaluate Bt-cry1Ia1 transgenic potato lines. The results are summarized in Table 7. Spunta G2 and Spunta G3 have good agronomic performance and good type. Two Bt-Atlantic lines were in the trial, but were dropped because of their poor vine growth. Four of the five Bt-Lady Rosetta line performed as well as the non-transgenic Lady Rosetta, but the performance of these Lady Rosetta and the Bt-lines were poor and susceptible to hollow heart. H. Water Management Trials (Tables 8A and 8B) In 2003 and 2004 a series of field trials were conducted to compare the agronomic performance of varieties and lines when grown with and without irrigation. In 2004 20 clones were compared. In the irrigated trial, agronomic performance was typical of other irrigated trials at the Montcalm Research Farm. In the non-irrigated trial, yields were about 60%, vine maturity ratings were half, frequency of hollow heart was reduced and specific gravity was similar compared to the irrigated trial. Percent of US #1 potatoes for Michigan Purple, Boulder, Atlantic and MSJ080-1 were similar between irrigated and non-irrigated treatments. I. Potato Scab Evaluation (Table 9) common and pitted scab. 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 9 categorizes many of the varieties and advanced selections tested in 2004 at the MSU Soils Farm Scab Nursery over a Each year a replicated field trial at the MSU Soils Farm is conducted to assess resistance to 22 In 2004, a late blight trial was conducted at the Muck Soils Research Farm. Over 100 three-year period. 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 2004 the scab disease incidence at the nursery was typical compared to other years, and the data were separated into three categories (Resistant = 0.0-1.0; Moderately Resistant = 1.3 – 1.8; 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 9). In general, most russet lines were scab resistant. 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 MSU lines are Liberator, MSG227-2, MSE192- 8RUS, MSE202-3RUS, MSE221-1, MSH228-6, MSK409-1, MSL211-3, MSN251-1Y, MSJ126- 9Y, MSJ033-10Y, MSK061-4, MSK476-1, and MSJ036-A. The greater number of MSU lines in the resistant and moderately resistant categories indicates we are making progress in breeding more scab resistant lines for the chip-processing and tablestock markets. Scab results from the disease nursery are also found in the Trial Summaries (Tables 2-6B). J. Late Blight Trial (Table 10) entries were evaluated in replicated plots. The field was planted on June 23 and inoculated July 30 with a combinations of isolates (see Table 10 for isolates), 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. The partial results are summarized in Table 10. The first column lists the lines classified as resistant, while the second column lists select varieties that are susceptible. The late blight differential lines LBR8 and LBR9 were resistant in 2004 as in previous years (not shown in table). Twenty-eight MSU lines were highly resistant to late blight. Resistance of the MSU lines is derived from Tollocan (a Mexican variety), B0718-3 (USDA clone), AWN96518-2 (USDA clone), Stirling (Scottish variety), NY121 (Cornell University clone) and Jacqueline Lee (MSU variety). These resistant progeny indicate that we can continue to breed for resistance using this group of resistant clones. Some of the most promising late blight resistant clones are MSJ461-1, MSL159-AY, MSL179-AY, MSM171-A, MSL794-BRUS, MSL211-3, MSN105-1, MSN251-1Y, MSI152-A and MSK136-2. We find these late blight resistant lines valuable because many of them also have marketable maturity. Some 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 the selections with foliar late blight resistance. K. Blackspot Susceptibility (Table 11) 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 Increased evaluations of advanced seedlings and new varieties for their susceptibility to 23 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 11. 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 2004 the bruise levels were higher other years. The most bruise resistant lines this year were FL1922, Keystone Russet, Stampede Russet, MSA8254-2BRUS, GoldRush, MSK409-1, MSK437-A, Dakota Jewel, MSN125-2, MSN084-3, MSL183-AY, MSI049-A, BTX1544-2W/Y, MSJ317-1, NDTX4271-5R and MSE192- 8RUS. The most susceptible lines were MSEE018-1, ND2470-27, MSM183-1Y, MSL007-B, NY132, Millenium Russet, MSH095-4, UEC, FL1833, Snowden and Atlantic. 24 Table 1 LINE ATLANTIC MSH112-6 MICHIGAN PURPLE MSJ147-1 FL1833 SNOWDEN BOULDER UEC MSJ080-1 FL1879 MSF099-3 MSH095-4 MSH067-3 MSJ461-1LBR MSH094-8 MSH228-6 MSG227-2 B0766-3 JACQUELINE LEELBR LIBERATOR FL1922 FL1867 MEAN LSD0.05 DATE OF HARVEST TRIAL: EARLY HARVEST MONTCALM RESEARCH FARM AUGUST 11, 2004 (100 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV PO SP GR PERCENT (%) TUBER QUALITY3 CHIP SCORE2 HH VD IBS BC 3-YR AVG US#1 CWT/A 275 262 243 240 238 235 223 222 221 221 217 207 205 198 195 194 194 172 168 163 151 135 208 36 295 305 266 278 252 275 244 240 250 236 249 235 217 254 222 223 229 205 298 192 174 155 241 41 93 86 92 87 94 85 92 92 88 94 87 88 95 78 88 87 85 84 57 84 87 87 7 9 7 13 6 14 2 8 10 6 13 11 5 22 10 12 15 16 43 16 12 9 87 85 88 87 91 85 81 90 85 90 84 87 92 78 86 87 85 84 57 84 85 87 6 0 4 0 3 0 11 2 4 4 3 1 3 0 2 0 0 0 0 0 1 0 0 5 1 0 0 0 6 0 2 0 0 1 0 0 2 1 0 0 0 0 1 4 1.103 1.097 1.078 1.095 1.098 1.095 1.080 1.091 1.082 1.090 1.098 1.094 1.096 1.087 1.094 1.090 1.090 1.093 1.087 1.093 1.085 1.093 1.091 0.003 1.0 1.5 2.5 2.0 1.5 1.5 2.0 2.0 1.0 1.5 1.0 2.0 1.5 1.5 1.5 1.0 2.0 2.0 2.5 1.0 1.5 2.0 23 0 3 0 0 5 28 5 10 8 3 0 13 0 5 0 5 15 0 0 0 13 0 0 0 0 0 0 0 0 0 3 0 5 0 5 5 5 3 0 0 0 5 0 5 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 264 270* 265 271* 263* 213 229 225 235* 238* 219 224 200* 191 177 181* 197 - 185 194 171* 187* * Two-Year Average LBR Line(s) demonstrated foliar resistance to Late Blight ( Phytopthora infestans ) in inoculated field trials at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. 3QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Percent of 40 Oversize and/or A-size tubers cut. Planted May 3, 2004 25 Table 2 LINE ATLANTIC MSJ147-1 BOULDER MSJ461-1LBR MSF099-3 MICHIGAN PURPLE FL1833 SNOWDEN UEC MSG227-2 MSH094-8 MSH228-6 FL1879 MSJ080-1 MSH095-4 MSH067-3 B0766-3 JACQUELINE LEELBR LIBERATOR FL1922 FL1867 MEAN LSD0.05 DATE OF HARVEST TRIAL: LATE HARVEST MONTCALM RESEARCH FARM SEPTEMBER 20, 2004 (140 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV PO SP GR SCORE2 HH VD IBS BC SCAB4 MAT5 PERCENT (%) TUBER QUALITY3 CHIP 350 320 317 292 283 281 277 275 273 261 259 253 248 241 216 213 212 194 188 167 160 251 45 363 353 359 349 314 303 289 315 289 286 279 275 259 267 235 233 240 321 222 193 183 282 48 96 91 88 84 90 93 96 87 94 91 93 92 96 90 92 91 88 60 85 86 88 3 9 2 15 9 6 3 11 5 8 7 7 4 8 8 5 11 39 14 11 10 87 88 67 82 85 90 81 83 83 87 90 89 93 82 91 80 85 60 84 84 87 9 2 22 2 5 3 15 4 12 4 3 3 3 8 1 11 4 0 1 2 1 1 0 10 1 1 2 1 2 1 1 0 1 0 2 0 4 1 1 1 3 3 1.104 1.094 1.083 1.086 1.098 1.078 1.099 1.095 1.092 1.093 1.097 1.095 1.092 1.084 1.094 1.097 1.096 1.091 1.091 1.086 1.093 1.092 0.003 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 1.0 1.0 1.0 1.0 1.0 28 5 35 0 3 3 10 5 5 13 10 8 5 20 5 28 20 0 3 0 10 10 13 0 5 0 10 10 25 8 3 8 10 18 10 28 0 3 10 13 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 3 0 8 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2.4 1.8 1.8 1.8 2.5 3.3 2.0 1.9 1.5 0.8 2.0 1.3 2.5 2.3 2.5 2.7 1.8 2.7 0.3 1.0 1.5 4.0 3.8 3.5 4.0 3.5 2.5 3.5 3.5 4.0 4.0 3.3 4.3 2.3 3.5 2.8 3.5 3.8 3.5 3.3 3.0 3.0 3-YR AVG US#1 CWT/A 340 302* 353 297 311 315 289* 270 324* 280 265 270* 306* 300* 280 252* - 237 249 199* 196* * Two-Year Average LBR Line(s) demonstrated foliar resistance to Late Blight ( Phytopthora infestans ) in inoculated field trials at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. 3QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Percent of 40 Oversize and/or A-size tubers cut. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: August 12, 2004; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) Planted May 3, 2004 26 Table 3 MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS RUSSET and LONG TYPES TRIAL MONTCALM RESEARCH FARM SEPTEMBER 15, 2004 (135 DAYS) LINE GEMSTAR (A9014-2RUS)-NCR KEYSTONE RUSSET A8254-2BRUS SILVERTON RUSSET A9305-10 V1102-1-NCR MSL794-BRUSLBR A8893-1 A95409-1 MSE202-3RUS WALLOWA RUSSET MILLENIUM RUSSET GOLDRUSH MSL025-ARUS RUSSET BURBANK-NCR AC89536-5RUS RUSSET NORKOTAH-NCR ND7882b-7RUS-NCR MSE192-8RUS AC STAMPEDE RUSSET-NCR MN99460-21-NCR MEAN LSD0.05 CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV PO SP GR HH VD IBS BC SCAB3 MAT4 PERCENT (%) TUBER QUALITY2 3-YR AVG US#1 CWT/A 320 303 271 269 258 234 226 213 200 191 191 178 176 165 147 138 126 125 124 94 61 191 72 400 343 397 307 344 283 283 322 285 254 255 268 256 283 265 263 220 246 208 157 149 276 76 80 88 68 88 75 83 80 66 70 75 75 66 69 58 56 52 58 51 59 60 41 17 10 27 13 21 16 17 31 27 21 21 27 30 41 40 46 41 47 34 39 58 75 68 61 66 71 76 70 65 66 67 63 65 63 56 55 50 58 49 57 57 41 5 20 7 23 4 7 9 1 4 8 12 1 6 2 1 3 0 1 3 3 0 3 2 4 2 4 1 3 3 3 3 4 7 2 1 5 2 1 2 7 2 1 1.093 1.073 1.084 1.080 1.086 1.085 1.085 1.087 1.090 1.084 1.093 1.086 1.076 1.079 1.084 1.084 1.082 1.080 1.076 1.064 1.082 1.083 0.005 15 3 15 0 0 0 0 3 0 15 5 3 0 0 0 5 0 3 0 0 0 3 40 3 5 15 8 3 8 0 3 23 3 13 15 3 18 5 5 3 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 3 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0.8 0.5 0.0 0.0 1.5 1.0 2.0 0.5 1.8 1.0 3.0 0.3 0.0 0.8 0.8 0.3 1.3 - 1.0 0.5 2.3 4.3 4.0 4.3 4.5 4.5 1.5 3.8 3.5 3.0 4.3 3.5 3.8 2.0 4.0 3.0 3.0 1.3 1.0 2.8 2.3 1.3 - 301* 291* 193 255* - - - 212* 213 - - 198 - 195 210 - - 183 - - * Two-Year Average LBR Line(s) demonstrated foliar resistance to Late Blight ( Phytopthora infestans ) in inoculated field trials at the MSU Muck Soils Research Farm. 1SIZE: B: < 4oz.; A: 4-10oz.; OV: > 10oz.; PO: Pickouts. 2QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Percent of 40 Oversize and/or A- size tubers cut. 3SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 4MATURITY RATING: August 28, 2003; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering). Planted May 3, 2004 27 Table 4 ENTRY ROUND WHITES: W1773-7 USDA02-20066 NORVALLEY ATLANTIC SNOWDEN W2128-8 USDA02-20312 MSJ317-1LBR MSH095-4 MSI152-ALBR USDA02-20152 W1443 MSH031-5 MN99380-1 MN96001-2 V0319-1 USDA02-20059 REDS: RED PONTIAC FV12486-2 CV89023-2R VILLETA ROSE (W2275-3R) RED NORLAND MN96013-1 NORTH CENTRAL REGIONAL TRIAL MONTCALM RESEARCH FARM SEPTEMBER 6, 2004 (126 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 PERCENT (%) CHIP TUBER QUALITY3 US#1 TOTAL US#1 Bs As OV PO SP GR SCORE2 HH VD IBS BC SCAB4 MAT5 MERIT6 283 272 260 271 259 221 237 238 228 217 123 167 175 101 135 104 75 412 258 226 144 192 84 342 325 314 309 290 288 286 270 263 253 242 214 203 171 168 153 132 440 284 284 244 221 117 83 84 83 87 89 77 83 88 87 86 51 78 86 59 80 68 56 94 91 80 59 87 72 16 15 15 6 9 21 16 9 11 13 45 17 13 40 18 32 41 5 9 20 41 12 25 82 83 82 74 86 76 83 87 86 84 51 78 86 59 79 67 56 85 85 80 59 87 69 1 1 1 13 4 0 0 1 1 2 0 1 0 0 1 1 0 8 5 0 0 0 3 1 1 2 7 2 2 1 2 2 1 4 5 1 1 2 0 3 2 0 0 0 1 3 1.101 1.084 1.085 1.098 1.098 1.101 1.098 1.085 1.093 1.075 1.091 1.088 1.086 1.078 1.075 1.084 1.060 1.074 1.070 1.077 1.060 1.069 1.076 1.0 2.5 1.5 1.0 1.5 1.5 1.5 1.0 1.5 1.5 1.5 1.0 1.5 1.0 2.0 1.5 2.0 2.5 2.0 2.5 2.0 2.5 1.5 0 8 0 45 10 0 5 10 5 0 30 28 0 0 0 3 0 13 0 0 0 0 0 3 10 5 3 13 3 13 10 28 3 0 8 3 15 10 0 15 5 5 0 0 3 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1.8 - 1.5 2.4 1.9 0.7 - 2.5 2.5 1.0 - 1.0 2.7 2.0 1.5 - - 3.0 1.5 1.0 - 1.7 3.0 4.0 5.0 2.5 3.3 4.0 3.3 3.8 5.0 1.8 4.5 2.5 2.5 2.5 1.0 1.0 1.5 1.0 4.0 1.8 1.3 1.3 1.0 1.5 3 1 2 2 1 3 28 NORTH CENTRAL REGIONAL TRIAL MONTCALM RESEARCH FARM SEPTEMBER 6, 2004 (126 DAYS) ENTRY RUSSET / LONG TYPES: GEMSTAR (A9014-2RUS) V1102-1 RUSSET BURBANK ND7882b-7RUS RUSSET NORKOTAH AC STAMPEDE RUSSET MN99460-21 MEAN LSD0.05 CWT/A PERCENT OF TOTAL1 PERCENT (%) CHIP TUBER QUALITY3 US#1 TOTAL US#1 Bs As OV PO SP GR SCORE2 HH VD IBS BC SCAB4 MAT5 MERIT6 320 234 147 125 126 94 61 203 45 400 283 265 246 220 157 149 253 50 80 83 56 51 58 60 41 17 16 40 47 41 39 58 75 76 55 49 58 57 41 5 7 1 1 0 3 0 3 1 5 2 1 2 1 1.093 1.085 1.084 1.080 1.082 1.064 1.082 1.083 0.003 - - - - - - - 15 0 0 3 0 0 0 3 8 3 5 5 3 0 0 0 3 3 0 0 3 0 0 0 0 0 0 0 0.8 1.0 0.8 - 1.3 0.5 2.3 4.3 1.5 3.0 1.0 1.3 2.3 1.3 1 3 2 LBR Line(s) demonstrated foliar resistance to Late Blight ( Phytopthora infestans ) in inoculated field trials at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. 3QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Percent of 40 Oversize and/or A-size tubers cut. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: August 24, 2004; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering). 6MERIT: A Merit rating was given for the best 3 entries within each market class (rank order, 1 = best). Planted May 3, 2004 29 Table 5A LINE MSJ036-A A91814-5 MSL766-1LBR ATLANTIC NY126(Y) MSK498-1Y W2128-8 SNOWDEN MSM051-3 MSL007-B W52-26LBR MSK476-1 W2133-1 MSK061-4 MSK128-ALBR MSK049-A MSK136-2LBR MSK009-B PIKE W2154-1 MSM170-2 AF2211-9 MSM046-4 W2233-2 ADAPTATION TRIAL, CHIP-PROCESSING LINES MONTCALM RESEARCH FARM SEPTEMBER 20, 2004 (140 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV PO SP GR SCORE2 HH VD IBS BC SCAB4 MAT5 CHIP PERCENT (%) TUBER QUALITY3 362 324 317 307 280 275 268 263 260 254 251 242 240 240 237 232 231 224 223 219 213 206 197 196 386 377 341 326 297 305 329 292 279 287 285 286 276 275 267 311 280 246 249 277 250 221 247 228 94 86 93 94 94 90 81 90 93 88 88 85 87 87 89 75 82 91 90 79 85 93 80 86 6 9 5 5 5 9 16 8 6 12 12 14 13 13 11 25 17 6 9 18 14 5 19 13 86 77 66 82 85 89 81 87 88 85 87 84 84 87 89 73 82 82 89 78 83 90 80 86 8 9 27 13 9 1 0 4 6 3 1 1 3 0 0 2 0 9 1 1 2 3 0 0 0 5 2 1 1 1 3 2 0 0 0 2 0 0 1 1 0 2 1 3 1 2 1 1 1.096 1.094 1.085 1.105 1.095 1.090 1.105 1.097 1.091 1.094 1.083 1.109 1.097 1.098 1.093 1.097 1.094 1.087 1.099 1.098 1.087 1.094 1.097 1.086 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.5 1.0 1.5 1.0 1.5 1.0 1.5 1.0 1.0 1.0 1.0 1.0 1.0 1.5 18 3 5 53 8 0 0 3 10 3 0 3 3 0 0 0 0 5 0 8 0 45 0 8 5 5 0 3 3 5 10 25 0 3 0 8 13 18 0 5 0 0 5 3 0 10 15 8 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8 0 0 0 0 0 3 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.8 2.8 2.3 2.4 1.5 1.5 0.7 1.9 1.0 2.0 1.8 1.3 1.5 1.3 2.8 2.3 3.0 1.5 0.9 1.7 4.0 2.3 1.3 2.3 3.3 4.3 4.0 3.5 3.5 4.8 2.8 3.5 3.5 4.8 2.8 5.0 4.0 4.0 1.8 3.8 5.0 3.5 4.5 1.0 3.3 1.3 5.0 1.8 30 ADAPTATION TRIAL, CHIP-PROCESSING LINES MONTCALM RESEARCH FARM SEPTEMBER 20, 2004 (140 DAYS) LINE MSJ126-9Y NY132 W2145-11 MSK409-1 MEAN LSD0.05 CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV PO SP GR SCORE2 HH VD IBS BC SCAB4 MAT5 CHIP PERCENT (%) TUBER QUALITY3 192 176 171 155 241 48 213 208 201 191 276 47 90 84 85 81 10 15 14 14 86 84 85 80 4 1 0 1 0 1 1 5 1.088 1.110 1.101 1.092 1.095 0.004 1.0 1.0 1.0 1.0 3 8 3 0 5 0 0 5 0 0 0 0 0 0 0 0 1.3 1.5 1.0 1.3 1.8 4.8 3.8 2.0 LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. 3QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Percent of 40 Oversize and/or A-size tubers cut. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: August 24, 2004; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) Planted May 3, 2004 31 Table 5B LINE KEUKA GOLD MSM224-1LBR MSL072-CLBR MSI049-AMRLBR MSM171-ALBR MSJ204-3 STIRLINGLBR MSI005-20Y ONAWAY YUKON GOLD MSM137-2LBR MSM183-1YLBR MSK437-A MSM037-3 MSL211-3LBR MSL228-1 MSJ033-10Y MSK125-3MRLBR DAKOTA JEWEL MODOC MEAN LSD0.05 ADAPTATION TRIAL, TABLESTOCK LINES MONTCALM RESEARCH FARM SEPTEMBER 13, 2004 (133 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS US#1 TOTAL US#1 Bs As OV PO SP GR HH VD IBS BC SCAB3 MAT4 PERCENT (%) TUBER QUALITY2 CWT/A PERCENT OF TOTAL1 360 347 331 288 280 279 269 242 242 239 237 225 293 289 213 218 214 212 180 164 256 50 374 404 359 318 305 304 322 281 294 246 273 337 303 318 243 245 259 276 212 218 295 49 96 86 92 90 92 92 83 86 82 97 87 67 97 91 88 89 83 77 85 76 4 11 7 8 8 5 15 13 9 3 11 25 3 5 10 8 13 15 14 24 90 80 86 82 88 84 81 84 78 87 83 65 59 79 85 88 82 74 85 75 6 6 6 8 4 8 2 3 4 10 3 1 38 11 3 0 1 3 0 1 0 3 1 1 1 3 2 1 9 0 2 9 1 4 2 3 4 8 1 1 1.087 1.084 1.085 1.080 1.073 1.083 1.081 1.083 1.071 1.090 1.080 1.097 1.082 1.076 1.080 1.090 1.082 1.082 1.080 1.070 1.082 0.003 0 0 0 8 0 0 28 0 0 10 8 0 18 20 0 0 0 8 0 3 8 3 3 0 5 0 5 5 10 8 3 0 3 8 8 10 8 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 18 0 0 3 0 0 0 3 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0.8 2.3 2.0 2.3 2.5 1.7 2.3 1.3 1.0 3.0 3.0 2.3 2.0 1.3 1.3 1.8 1.0 1.8 0.8 2.0 4.5 5.0 4.5 2.5 1.3 4.5 4.3 2.3 1.3 1.3 1.0 5.0 4.8 4.8 1.5 2.3 3.3 4.3 1.0 1.8 LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials 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. Percent of 40 Oversize and/or A-size tubers cut. 3SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 4MATURITY RATING: August 24, 2004; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) Planted May 3, 2004 32 Table 6A LINE MSN251-1YLBR MSN125-2 MSM164-2Y MSN144-2 ATLANTIC MSN105-1LBR MSM057-D MSL235-AYMRLBR MSN184-2 MSM409-2Y MSM185-1MRCPB MSN065-2 MSM070-1 MSM205-A SNOWDEN MSN179-5 MSM170-B MSN174-3 MSM039-B MSN094-3 MSN236-1 MSM051-A MSN085-2Y MSN026-4 MSL292-A MSL106-AY MSL268-DLBR PRELIMINARY TRIAL, CHIP-PROCESSING LINES MONTCALM RESEARCH FARM SEPTEMBER 13, 2004 (133 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV CHIP PERCENT (%) TUBER QUALITY3 PO SP GR SCORE2 HH VD IBS BC SCAB4 MAT5 412 382 374 373 365 360 320 314 297 295 288 280 277 267 265 264 263 261 260 258 240 231 222 219 217 216 215 461 405 417 398 384 396 354 349 318 337 334 323 314 306 298 312 283 326 317 302 301 275 271 256 247 269 260 89 94 90 94 95 91 90 90 93 87 86 87 88 87 89 85 93 80 82 85 80 84 82 86 88 81 83 6 6 5 6 3 9 8 7 7 11 9 10 11 10 11 10 7 20 17 14 17 14 18 14 11 16 17 75 92 66 73 81 91 81 79 83 84 82 83 84 83 85 82 83 80 81 81 80 83 82 86 85 78 83 14 3 24 20 14 0 10 11 10 4 4 4 4 4 4 3 10 0 1 5 0 1 0 0 3 3 0 5 0 6 1 2 0 1 3 0 2 5 3 1 3 0 6 0 0 1 1 3 2 1 0 1 4 1 1.094 1.091 1.081 1.081 1.102 1.094 1.091 1.081 1.085 1.089 1.094 1.098 1.086 1.086 1.095 1.094 1.086 1.079 1.102 1.094 1.103 1.089 1.107 1.097 1.093 1.081 1.088 1.0 1.0 1.5 1.0 1.0 1.0 1.0 1.0 1.0 2.0 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 1.0 1.0 35 0 45 15 60 0 0 25 0 20 5 10 0 0 10 0 5 10 0 45 0 15 5 0 10 35 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 5 0 0 0 0 0 0 45 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1.0 2.0 1.3 1.3 2.4 1.3 2.7 1.7 - 3.0 1.0 - 1.3 2.0 1.9 1.8 1.7 1.5 1.8 1.3 1.8 3.0 2.0 1.5 2.0 2.7 2.0 5.0 5.0 5.0 4.0 3.5 4.0 4.0 5.0 4.5 4.5 5.0 2.5 3.0 3.0 3.5 3.5 2.5 3.0 4.0 5.0 4.0 3.5 3.5 3.5 2.5 3.0 3.5 33 PRELIMINARY TRIAL, CHIP-PROCESSING LINES MONTCALM RESEARCH FARM SEPTEMBER 13, 2004 (133 DAYS) LINE PIKE MSM188-1MRCPB MSM060-3 MSM053-4 MSN098-4 MSM408-B MSN209-3LBR MEAN LSD0.05 CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV CHIP PERCENT (%) TUBER QUALITY3 PO SP GR SCORE2 HH VD IBS BC SCAB4 MAT5 214 211 205 194 183 160 155 266 66 234 253 261 209 212 187 202 305 68 91 84 79 93 87 86 77 8 16 20 7 11 13 11 90 83 79 84 87 80 72 1 1 0 9 0 6 5 0 0 1 0 3 2 12 1.097 1.099 1.103 1.089 1.081 1.093 1.092 1.092 0.005 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0 10 5 55 0 0 0 0 0 10 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0.9 - 1.0 2.0 1.3 - 2.0 4.5 2.5 2.5 5.0 2.5 3.5 4.5 LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials at the MSU Muck Soils Research Farm. 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. 3QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Percent of 20 Oversize and/or A-size tubers cut. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: August 24, 2004; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) Planted May 3, 2004 34 Table 6B LINE MSL179-AYLBR MSN188-1 MSN228-5LBR MSL006-AY ARS4008-1 MSL045-AYLBR MSL183-AYLBR MSN084-11 ONAWAY MSM417-ALBR MSN077-2 MSN084-3 MSL024-AYLBR MSL175-1 NDMS7994-1RUS MSM143-ALBR MSM224-2LBR MSM148-ALBR MEAN LSD0.05 PRELIMINARY TRIAL, TABLESTOCK LINES MONTCALM RESEARCH FARM SEPTEMBER 13, 2004 (133 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV CHIP PO SP GR SCORE2 HH VD IBS PERCENT (%) TUBER QUALITY3 BC 358 305 297 292 275 272 269 250 247 245 240 213 210 166 140 138 138 132 233 87 405 366 411 324 333 297 327 261 287 304 262 229 297 171 255 193 161 204 283 79 88 83 72 90 83 92 82 96 86 81 92 93 71 97 55 72 86 64 10 15 27 9 9 8 17 4 10 18 8 6 28 3 44 28 14 35 81 82 72 87 79 89 82 74 83 79 90 88 71 80 54 72 86 64 7 1 0 3 4 3 0 21 3 1 2 5 0 17 1 0 0 0 2 2 1 1 8 0 1 0 4 1 0 1 1 0 1 0 0 0 1.088 1.087 1.088 1.088 1.079 1.077 1.073 1.069 1.070 1.089 1.084 1.075 1.077 1.077 1.089 1.082 1.079 1.091 1.081 0.003 3.0 2.5 1.0 1.5 4.0 1.5 1.0 1.5 4.0 1.0 1.0 1.5 2.0 1.5 2.5 1.0 2.5 1.0 0 10 0 0 0 0 0 5 0 40 0 0 0 0 0 0 5 0 10 0 0 15 5 0 0 0 0 0 0 0 5 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 5 0 0 35 0 0 0 15 0 0 0 0 0 0 SCAB4 MAT5 2.3 3.0 3.0 4.0 1.8 3.0 2.0 3.0 1.0 2.7 3.0 2.0 2.3 2.0 0.0 1.5 3.0 1.0 4.0 4.0 4.5 3.0 2.0 2.0 2.5 4.0 1.0 2.5 4.0 3.0 1.0 3.0 2.0 1.5 1.0 3.5 LBR Line(s) demonstrated foliar resistance to Late Blight ( Phytopthora infestans ) in inoculated field trials at the MSU Muck Soils Research 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. 3QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Percent of 20 Oversize and/or A-size tubers cut. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: August 24, 2004; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) Planted May 3, 2004 35 Table 7 LINE Spunta-G3 Spunta-G2 Atlantic Spunta Atlantic Newleaf Lady Rosetta-5.3 Lady Rosetta-5.4 Lady Rosetta-5.1 Lady Rosetta-5.2 Lady Rosetta Lady Rosetta-5.6 MEAN LSD0.05 TRANSGENIC TRIAL MONTCALM RESEARCH FARM SEPTEMBER 7, 2004 (127 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL1 US#1 TOTAL US#1 Bs As OV PO SP GR SCORE2 HH VD IBS BC SCAB4 PERCENT (%) TUBER QUALITY3 CHIP 354 324 313 234 226 114 113 104 104 97 67 186 418 380 336 278 262 210 219 213 193 200 158 261 85 85 93 84 86 54 52 49 54 49 43 11 8 5 8 12 46 48 51 40 51 56 79 79 86 75 83 54 52 49 54 49 43 5 6 7 9 4 0 0 0 0 0 0 4 7 2 8 1 0 0 0 6 1 1 1.072 1.072 1.107 1.070 1.104 1.100 1.102 1.094 1.106 1.102 1.099 1.093 2.0 2.0 1.0 2.0 1.0 1.5 1.5 1.0 1.5 1.5 1.5 1 1 10 2 7 20 10 13 16 14 2 6 3 2 7 2 1 0 0 0 0 0 4 1 3 0 1 2 0 1 0 0 0 0 0 0 0 2 0 0 0 0 0 0 1.8 2.0 2.1 2.3 2.0 nd nd nd nd 1.0 nd 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. 3QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Percent of 40 Oversize and/or A-size tubers cut. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. nd = no data Planted May 3, 2004 36 Table 8A MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS WATER MANAGEMENT TRIAL: STANDARD IRRIGATION TREATMENT MONTCALM RESEARCH FARM SEPTEMBER 24, 2004 (130 DAYS) LINE ATX91137-1RU MSJ080-1 BOULDER MSE018-1 CO089097-2R NDTX4271-5R MSJ147-1 Atlantic Michigan Purple MSI049-A NDTX4304-1R MSG227-2 MSJ461-1 Onaway Snowden BTX1544-2W/Y MSJ317-1 Russet Norkotah MSH228-6 MSE192-8RUS MEAN LSD0.05 CWT/A US#1 TOTAL 366 360 357 349 332 323 321 313 308 295 294 279 276 268 264 254 200 199 192 105 283 50 410 387 393 390 373 362 345 346 328 329 326 307 368 319 302 286 268 255 215 193 325 51 PERCENT OF TOTAL1 US#1 Bs As OV PO SP GR HH VD IBS BC MAT5 PERCENT (%) TUBER QUALITY3 89 93 91 90 89 89 93 90 94 90 90 91 75 84 87 89 74 78 90 54 9 6 2 8 10 9 7 9 4 10 9 8 25 7 13 11 23 16 5 43 84 86 56 82 87 87 92 89 87 88 89 85 75 81 84 89 74 72 87 54 5 7 35 8 2 2 1 2 7 1 1 5 0 3 3 0 0 6 3 0 1 1 8 2 1 1 0 0 2 0 1 1 0 9 0 0 2 6 5 2 0 7 13 20 0 0 13 3 3 0 0 10 0 0 13 3 13 13 27 0 0 3 0 3 13 0 0 0 0 0 7 0 3 20 20 0 0 0 13 3 0 0 0 0 0 0 0 7 0 0 0 0 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 1.076 1.084 1.082 1.092 1.083 1.073 1.094 1.103 1.077 1.078 1.062 1.088 1.085 1.069 1.096 1.082 1.086 1.077 1.086 1.078 1.083 0.003 4.7 4.0 5.0 5.0 3.7 3.0 4.3 4.7 3.0 3.0 2.0 4.0 5.0 2.7 4.0 2.0 5.0 4.0 4.0 2.7 3.8 0.9 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. 3QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Percent of 30 Oversize and/or A-size tubers cut. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: Taken August 12, 2004; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) Planted May 17, 2004 37 Table 8B LINE Michigan Purple Atlantic MSI049-A NDTX4304-1R MSJ080-1 Boulder BTX1544-2W/Y Snowden CO89097-2R Onaway ATX91137-1RU MSJ147-1 MSE018-1 MSJ461-1 MSH228-6 NDTX4271-5R MSJ317-1 MSG227-2 Russet Norkotah MSE192-8RUS MEAN LSD0.05 WATER MANAGEMENT TRIAL: NON-IRRIGATED TREATMENT MONTCALM RESEARCH FARM SEPTEMBER 15, 2004 (132 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A US#1 TOTAL 227 212 202 186 186 181 176 173 173 170 164 161 155 147 143 141 133 128 74 35 158 44 265 243 255 226 208 237 214 226 245 211 242 210 197 221 200 181 176 175 131 131 210 42 PERCENT OF TOTAL1 US#1 Bs As OV PO SP GR HH VD IBS BC MAT5 PERCENT (%) TUBER QUALITY3 86 87 79 82 89 77 83 77 71 80 68 77 79 66 71 78 76 73 56 27 11 10 18 16 10 8 16 22 25 12 29 23 19 33 17 19 20 25 39 73 85 86 79 80 87 74 82 77 70 80 68 77 78 66 69 76 76 73 56 27 1 1 1 2 2 3 1 0 1 1 0 0 1 0 2 2 0 0 0 0 4 2 3 2 1 16 2 1 4 7 3 0 2 1 12 3 4 2 5 0 0 3 0 0 0 23 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 13 0 7 3 0 3 10 7 20 10 7 23 3 7 3 27 0 7 0 0 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 0 0 0 7 0 3 0 0 3 0 0 0 0 0 0 0 0 0 0 3 0 0 1.081 1.097 1.075 1.064 1.080 1.090 1.078 1.090 1.078 1.074 1.077 1.092 1.090 1.079 1.089 1.066 1.081 1.091 1.069 1.073 1.081 0.005 1.7 2.0 1.0 1.0 2.0 3.7 1.0 1.7 1.0 1.0 1.0 2.7 3.0 2.0 3.0 1.0 4.7 2.0 1.3 1.0 1.9 0.5 1SIZE: B: <2"; A: 2-3.25"; OV: >3.25"; PO: Pickouts. 2CHIP SCORE: Snack Food Association Scale (Out of the field); Ratings: 1-5; 1: Excellent, 5: Poor. 3QUALITY: HH: Hollow Heart; BC: Brown Center; VD: Vascular Discoloration; IBS: Internal Brown Spot. Percent of 30 Oversize and/or A-size tubers cut. 4SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. 5MATURITY RATING: Taken August 12, 2004; Ratings 1-5; 1: Early (vines completely dead); 5: Late (vigorous vine, some flowering) Planted May 5, 2004 38 Table 9 2002-2004 SCAB DISEASE TRIAL SUMMARY SCAB NURSERY, EAST LANSING, MI MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS 2004 2004 RATING WORST N 2004 LINE Sorted by ascending 2004 Rating; A8254-2BRUS Goldrush MSND7994-1 Silverton Russet AC89536-5RUS Liberator Millenium Russet A8893-1 Keystone Russet Stampede Russet Keuka Gold Dakota Jewel GemStar (A9014-2) MSG227-2 MSJ036-A MSL025-ARUS Russet Burbank Pike Atlantic 5.4 CV89023-2R FL1922 Lady Rosetta MSE192-8RUS MSE202-3RUS MSI152-A MSJ033-10Y MSL045-AY MSM051-3 MSM060-3 MSM148-A MSM185-1 MSN251-1Y Onaway V1102-1 Villetta Rose W1443 W2145-11 MSH228-6 MSI005-20Y 0.0 0.0 0.0 0.0 0.3 0.3 0.3 0.5 0.5 0.5 0.7 0.8 0.8 0.8 0.8 0.8 0.8 0.9 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 1.0 1.0 1.0 1.3 1.3 2003 2003 RATING WORST N 2003 2002 2002 RATING WORST N 2002 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 3 1 1 1 1 1 1 1 1 1 1 1 2 1 1 2 2 4 4 4 4 4 4 4 2 4 2 3 4 4 4 4 4 4 7 3 1 4 5 3 3 3 3 2 4 4 2 4 1 5 2 4 4 4 4 4 0.0 1.0 - 0.3 0.0 0.0 0.7 - 0.5 0.3 - 1.0 1.0 0.8 1.3 0.7 0.5 1.5 - 3.0 1.3 2.0 0.3 0.3 3.0 - 3.0 1.0 0.7 - 3.3 - 1.4 - - - - 0.7 1.0 0 1 - 1 0 0 1 - 1 1 - 1 1 2 2 1 2 2 - 4 2 5 1 1 3 - 3 1 1 - 5 - 3 - - - - 1 1 3 2 - 3 3 3 3 - 2 3 - 3 3 6 3 3 6 8 - 3 3 3 3 3 3 - 1 1 3 - 3 - 9 - - - - 3 3 - 0.3 - - 0.0 0.0 0.0 0.0 0.5 - - 0.7 0.3 0.5 0.5 - - - - 3.0 - - 0.3 0.0 2.0 1.0 - - - - - - 1.7 - - - - 1.3 2.0 - 1 - - 0 0 0 0 1 - - 1 1 1 1 - - - - 3 - - 0 0 3 1 - - - - - - 3 - - - - 2 2 - 3 - - 2 2 3 3 2 - - 3 3 2 2 - - - - 3 - - 3 5 3 3 - - - - - - 7 - - - - 3 1 39 2004 2004 RATING WORST N 2004 2003 2003 RATING WORST N 2003 2002 2002 RATING WORST N 2002 LINE Sorted by ascending 2004 Rating; MSK061-4 MSK476-1 MSL211-3 MSM037-3 MSM164-2Y MSN094-3 MSN098-4 Russet Norkotah MSJ126-9Y MSK409-1 MSM046-4 MSM070-1 MSN105-1 MSN144-2 W2128-8 A9305-10 FL1867 FV12486-2 MN96001-2 MSK009-B MSK498-1Y MSM143-A MSM288-2Y MSN026-4 MSN174-3 NorValley NY126 NY132 UEC W2133-1 MSL235-AY MSM170-B Red Norland A95409-1 ARS4008-1 B0766-3 Boulder MSH094-8 MSJ147-1 MSJ204-3 MSJ461-1 MSK125-3 MSL228-1 MSM039-B 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.4 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.7 1.7 1.7 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 2 2 2 2 3 2 4 4 4 4 4 4 4 4 3 3 3 3 3 3 8 4 4 2 4 4 4 2 4 4 4 4 4 4 4 4 3 3 3 4 4 4 4 4 4 4 4 4 4 4 2.0 1.0 1.0 - 1.3 - - 2.0 1.3 0.7 0.7 - - - - 1.7 1.5 - - 3.0 2.7 - 2.5 - - 1.0 - - 1.3 - - - 0.7 0.0 - - 2.0 2.3 1.7 1.0 2.0 2.2 1.3 - 3 1 1 - 2 - - 2 2 1 1 - - - - 2 3 - - 3 4 - 3 - - 1 - - 2 - - - 1 0 - - 3 3 3 2 2 3 2 - 3 3 1 - 3 - - 3 3 3 3 - - - - 3 4 - - 3 3 - 2 - - 1 - - 6 - - - 3 2 - - 3 3 3 3 3 6 3 - 2.0 1.0 - - - - - - - 2.0 - - - - - - - - - - 1.3 - - - - 2.0 - - 1.5 - - - - - - - 2.5 2.3 2.0 2.0 2.7 - - - 1 2 - - - - - - - 2 - - - - - - - - - - 2 - - - - 2 - - 2 - - - - - - - 3 3 2 2 3 - - - 1 2 - - - - - - - 2 - - - - - - - - - - 3 - - - - 3 - - 4 - - - - - - - 2 3 3 2 3 - - - 40 2004 2004 RATING WORST N 2004 2003 2003 RATING WORST N 2003 2002 2002 RATING WORST N 2002 LINE Sorted by ascending 2004 Rating; MSN090-2 MSN179-5 MSN184-2 MSN236-1 SPG3 W1773-7 W2154-1 W52-26 Snowden Atlantic Newleaf FL1833 MN99380-1 Modoc MSH112-6 MSK437-A MSL007-B MSL072-C MSL175-1 MSL183-AY MSL268-D MSL292-A MSL794-BRUS MSM053-4 MSM061-A MSM084-3 MSM205-A MSN077-2 MSN085-2Y MSN125-2 MSN209-3 MSN267-14Y SPG2 Atlantic MN99460-1 MSH095-4 MSI049-A MSJ080-1 MSK049-A MSL766-1 MSM224-1 MSN188-1 MSN228-5 SP6a3 Spunta 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.9 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 2.1 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2 2 2 2 2 2 2 2 3 3 3 2 2 3 3 3 2 3 2 3 3 3 3 2 2 3 2 3 3 2 3 3 3 3 3 3 3 3 3 3 4 3 3 3 4 4 4 4 4 4 4 4 8 4 4 3 3 4 4 4 2 3 2 3 3 4 4 1 1 4 2 4 3 2 3 4 15 4 8 4 4 4 4 4 4 4 4 4 - - - - - 0.7 - - 2.4 - 1.7 - - 2.3 2.0 0.7 - 2.0 - - - - - - - 3.0 - - - - - - 2.3 - 1.7 2.3 2.0 - 2.2 - - - - 3.0 - - - - - 1 - - 3 - 2 - - 3 2 1 - 2 - - - - - - - 4 - - - - - - 4 - 2 3 2 - 3 - - - - 5 - - - - - 3 - - 12 - 3 - - 3 3 3 - 3 - - - - - - - 3 - - - - - - 11 - 3 3 3 - 6 - - - - 3 - - - - - 2.7 - - 2.0 - - - - 2.3 - - - - - - - - - - - - - - - - - - 2.7 - 2.0 2.5 2.5 2.3 - - - - - - - - - - - 3 - - 2 - - - - 3 - - - - - - - - - - - - - - - - - - 4 - 3 3 3 3 - - - - - - - - - - - 3 - - 5 - - - - 3 - - - - - - - - - - - - - - - - - - 11 - 3 2 2 3 - - - - - - 41 2004 2004 RATING WORST N 2004 2003 2003 RATING WORST N 2003 2002 2002 RATING WORST N 2002 LINE Sorted by ascending 2004 Rating; Stirling W2233-2 AF2211-9 MSL024-AY MSL179-DY MSM183-1Y Wallowa Russet FL1879 MSF099-3 MSJ317-1 MSK136-2 MSM051-A MSM171-A MSH031-5 MSL106-AY MSM057-D MSM417-A A91814-5 Jacqueline Lee MSH067-3 MSK128-A MN96013-1 MSM137-2 MSM224-2 MSM409-2Y MSN084-11 Red Pontiac Yukon Gold Michigan Purple MSL006-AY MSM170-2 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 2.7 2.7 2.7 2.7 2.8 2.8 2.8 2.8 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.3 4.0 4.0 3 3 3 3 3 3 4 3 3 3 3 3 4 3 3 3 4 3 3 3 4 3 3 4 4 3 3 4 4 4 5 4 4 3 3 3 3 3 4 4 4 4 4 4 3 3 3 3 4 4 4 4 1 4 3 4 2 4 4 4 1 4 2.7 - - - - - - - 2.7 3.7 2.0 - 2.0 1.7 - - 4.0 - 2.5 2.0 - - - - 2.7 - 3.2 2.3 2.3 - - 4 - - - - - - - 4 4 2 - 2 2 - - 5 - 3 3 - - - - 3 - 4 3 4 - - 3 - - - - - - - 3 3 3 - 3 3 - - 2 - 6 3 - - - - 3 - 6 3 6 - - - - - - - - - - 3.7 2.5 - - - 2.3 - - - - 2.7 3.0 - - - - - - 3.0 4.0 2.7 - - - - - - - - - - 4 3 - - - 3 - - - - 3 5 - - - - - - 3 5 3 - - - - - - - - - - 3 2 - - - 3 - - - - 3 3 - - - - - - 3 3 3 - - *SCAB DISEASE RATING: MSU Scab Nursery; 0: No Infection; 1: Low Infection <5%; 3: Intermediate; 5: Highly Susceptible. LSD0.05 = 1.0 LBR Line(s) demonstrated foliar resistance to Late Blight ( Phytopthora infestans ) in inoculated field trials in 2003 at the MSU Muck Soils Research Farm. 42 Table 10 2004 LATE BLIGHT VARIETY TRIAL MUCK SOILS RESEARCH FARM MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS RAUDPC1 MEAN Female Male LINE RAUDPC1 MEAN LINE Sorted by ascending RAUDPC value: Foliar Resistance Category: 0.0 MSL072-C MSL268-D 0.0 0.0 MSM183-1Y 0.3 MSM137-2 0.3 MSL766-1 Jacqueline Lee 0.4 0.4 Stirling 0.5 MSM148-A 0.7 MSL045-AY MSI152-A 0.7 0.8 MSJ461-1 1.3 MSL794-Brus 1.3 MSL603-319 MSL183-AY 1.6 1.7 MSM224-1 2.0 MSL211-3 2.3 MSK128-A MSL024-AY 2.3 2.4 MSM143-A 2.6 MSJ317-1 2.9 MSK136-2 MSM171-A 3.0 3.9 MSN209-3 4.0 MSN251-1Y 5.3 MSN228-5 W52-26 5.8 7.4 MSN105-1 7.6 MSK049-A 8.5 MSM409-2Y MSI049-A 9.4 Tollocan Jacqueline Lee Jacqueline Lee Jacqueline Lee A91846-5R Chaleur MSE033-1R NY103 Torridon Eramosa B0718-3 Tollocan SCRI variety Jacqueline Lee MSE028-1 Jacqueline Lee MSB107-1 B0718-3 Mainestay NY88 Tollocan A95053-61 A91194-4 Jacqueline Lee MSG227-2 Boulder MSB106-7 MSG301-9 Jacqueline Lee MSH094-3 AWN86514-2 MSF020-23 Jacqueline Lee MSE048-2Y Prestile B0718-3 B0718-3 Greta MSE221-1 Stirling MSJ319-1 MSJ462-2 MSG227-2 Torridon ND6947B-13 Jacqueline Lee Cornell University breeding line Jacqueline Lee MSG141-3 MSH142-2 Brodick MSJ365-6 MSJ456-4 Brodick MSC121-7 Tollocan Jacqueline Lee Jacqueline Lee Foliar Susceptibility Category (select lines) 2 : Snowden FL1879 FL1833 B0766-3 Red Pontiac Pike Atlantic Millenium Russet UEC FL1867 Keystone Russet NorValley Dakota Jewel Keuka Gold Silverton Russet Yukon Gold Wallowa Goldrush Onaway Russet Burbank Red Norland Modoc Villeta Rose Michigan Purple FL1922 15.7 16.4 20.6 22.2 22.3 22.4 22.4 22.6 22.8 23.9 24.6 25.2 26.1 26.6 27.1 27.9 28.1 28.6 29.3 29.3 30.1 30.1 30.6 35.1 35.6 LSD0.05 10.3 1 Ratings indicate the average plot RAUDPC (Relative Area Under the Disease Progress Curve). 2 111 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 10.3 and less are considered Phytopthora infestans isolates Pi02-007(US8), Pi99-2(US14), Pi95-2(US6), Pi95-3(US1) were inoculated 30 July 2004. Planted as a randomized complete block design consisting of 3 replications of 4 hill plots on 23 June 2004. 43 Table 11 ENTRY MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS 2004 BLACKSPOT BRUISE SUSCEPTIBILITY TEST SIMULATED BRUISE SAMPLES* NUMBER OF SPOTS PER TUBER 0 5+ 1 2 3 4 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER DATE OF HARVEST: LATE HARVEST FL1922 Boulder Liberator MSH094-8 Michigan Purple MSH228-6 MSJ147-1 MSJ461-1LBR MSG227-2 MSJ080-1 FL1867 B0766-3 Jacqueline LeeLBR MSF099-3 MSH095-4 FL1879 MSH067-3 Snowden UEC FL1833 Atlantic 25 16 13 9 11 9 8 8 7 8 5 6 8 5 4 6 3 3 1 3 1 5 6 12 7 9 10 9 9 8 13 9 6 9 11 5 7 6 8 6 5 2 4 2 6 7 6 6 7 7 3 7 7 9 7 10 9 11 9 6 8 2 2 2 1 1 2 2 1 4 3 4 2 2 4 6 5 6 8 7 1 1 1 2 2 2 100 64 52 36 44 36 32 32 28 32 20 24 32 20 16 24 12 12 4 12 4 0.0 0.6 0.8 0.9 0.9 0.9 1.0 1.1 1.2 1.2 1.2 1.3 1.3 1.3 1.4 1.5 1.7 1.7 1.9 2.0 2.4 * Twenty-five 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 November 9, 2004. The table is presented in ascending order of average number of spots per tuber. LBR Line(s) demonstrated foliar resistance to Late Blight (Phytopthora infestans ) in inoculated field trials at the MSU Muck Soils Research Farm. 44 ENTRY NUMBER OF SPOTS PER TUBER 0 5+ 1 2 4 3 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER RUSSET and LONG TYPES TRIAL 24 Keystone Russet 24 AC Stampede Russet-NCR Russet Norkotah-NCR 23 22 A8254-2BRUS 22 GoldRush 20 MSL025-ARUS MSE202-3RUS 19 19 Silverton Russet 21 A9305-10 ND7882b-7rus-NCR 18 17 MSE192-8RUS 18 V1102-1-NCR 17 Wallowa Russet A8893-1 13 16 GemStar(A9014-2RUS)-NCR 14 AC89536-5rus Russet Burbank-NCR 11 8 MN99460-21-NCR MSL794-BRUSLBR 4 A95409-1 7 4 Millenium Russet 1 1 2 3 2 5 6 6 2 5 6 4 6 12 6 7 12 9 8 3 5 1 1 2 2 3 2 3 4 2 5 8 8 11 1 3 5 6 1 1 1 1 ADAPTATION TRIAL, CHIP-PROCESSING LINES MSK409-1 MSK009-B W52-26LBR MSM046-4 MSK128-ALBR MSK498-1Y MSL766-1LBR W2128-8 MSJ036-A MSK061-4 MSK136-2LBR NY126 MSJ126-9Y MSM051-3 Pike W2233-2 20 18 18 12 11 9 10 15 9 7 6 11 8 6 7 9 5 7 3 8 9 12 10 5 9 13 15 7 8 10 11 8 3 5 4 3 4 2 7 5 4 5 7 9 4 4 1 2 2 3 2 96 96 92 88 88 80 76 76 84 72 68 72 68 52 64 56 44 32 16 28 16 80 72 72 48 44 36 40 60 36 28 24 44 32 24 28 36 1 4 1 2 2 0.0 0.0 0.1 0.1 0.2 0.2 0.2 0.2 0.3 0.4 0.4 0.4 0.4 0.5 0.5 0.6 0.6 1.1 1.6 1.6 1.8 0.2 0.3 0.5 0.7 0.8 0.8 0.9 0.9 0.9 0.9 0.9 0.9 1.1 1.1 1.1 1.2 45 ENTRY W2154-1 AF2211-9 MSK476-1 MSK049-A W2145-11 W2133-1 Snowden NY132 MSL007-B Atlantic NUMBER OF SPOTS PER TUBER 0 5+ 1 4 2 3 4 2 4 4 5 3 3 1 3 3 13 11 8 8 6 8 7 7 5 2 6 11 9 9 6 7 6 10 8 11 2 1 4 3 6 4 8 7 8 5 1 1 2 2 6 1 2 3 1 1 3 1 1 1 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER 16 8 16 16 20 12 12 4 12 12 88 84 80 80 76 72 68 68 68 68 60 52 56 60 52 40 36 52 4 96 92 88 80 84 80 84 1.2 1.4 1.5 1.6 1.8 1.8 1.9 1.9 2.0 2.2 0.1 0.2 0.2 0.2 0.2 0.3 0.3 0.4 0.4 0.4 0.4 0.5 0.6 0.6 0.7 0.8 0.9 0.9 2.0 0.0 0.1 0.1 0.2 0.2 0.2 0.2 1 1 ADAPTATION TRIAL, TABLESTOCK LINES MSK437-A Dakota Jewel Modoc MSM037-3 MSI049-AMRLBR MSJ033-10Y MSL228-1 MSM171-ALBR Yukon Gold MSL072-CLBR Keuka Gold MSL211-3LBR MSJ204-3 Onaway MSI005-20Y MSM137-2LBR MSK125-3MRLBR MSM224-1LBR MSM183-1YLBR 22 21 20 20 19 18 17 17 17 17 15 13 14 15 13 10 9 13 1 3 3 5 4 6 7 8 7 7 6 9 11 8 7 6 10 11 6 5 1 1 2 1 1 3 2 6 4 3 3 12 PRELIMINARY TRIAL, CHIP-PROCESSING LINES MSN098-4 MSN209-3LBR MSM051-A MSM170-B MSN094-3 MSN125-2 MSN184-2 24 23 22 20 21 20 21 1 2 3 5 3 5 3 1 1 46 ENTRY MSL235-AYMRLBR MSN065-2 MSM188-1MRCPB MSN174-3 MSM070-1 MSN105-1LBR MSN144-2 Pike MSM164-2Y MSM408-B MSM060-3 MSL106-AY MSN026-4 MSM039-B MSN236-1 MSM053-4 MSM205-A MSN179-5 MSL268-DLBR MSM185-1MRCPB MSM409-2Y MSM057-D MSN085-2Y MSL292-A MSN251-1YLBR Atlantic Snowden PRELIMINARY TRIAL, TABLESTOCK LINES MSN084-11 MSL183-AYLBR MSN084-3 MSM143-ALBR MSN077-2 MSL175-1 NDMS7994-1RUS MSM148-ALBR MSM417-ALBR ARS4008-1 MSL045-AYLBR 24 23 22 21 21 18 13 14 13 10 10 1 2 3 4 2 6 12 9 8 10 11 2 3 5 3 2 1 NUMBER OF SPOTS PER TUBER 0 5+ 1 4 2 3 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER 20 20 19 19 19 17 18 17 16 18 14 17 13 13 14 12 10 10 11 9 7 5 6 5 7 5 4 4 4 5 5 5 8 6 6 7 4 10 3 10 7 5 10 8 10 8 10 12 10 7 10 6 7 7 1 1 1 1 1 2 2 2 1 4 2 4 5 7 3 3 5 5 8 10 3 5 5 7 80 80 76 76 76 68 72 68 64 72 56 68 52 52 56 48 40 40 44 36 28 20 24 20 28 20 16 96 92 88 84 84 72 52 56 52 40 40 1 1 1 1 1 3 2 3 1 1 2 2 6 6 7 5 1 1 1 1 1 1 1 0.2 0.2 0.3 0.3 0.3 0.3 0.4 0.4 0.4 0.4 0.5 0.6 0.6 0.7 0.7 0.8 0.9 0.9 0.9 0.9 1.0 1.3 1.3 1.5 1.5 1.7 1.8 0.0 0.1 0.1 0.2 0.2 0.3 0.5 0.5 0.7 0.8 0.8 47 NUMBER OF SPOTS PER TUBER 0 5+ 1 2 3 4 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER ENTRY MSL006-AY MSN228-5LBR MSN188-1 MSL024-AYLBR Onaway MSL179-AYLBR 11 10 6 7 4 7 6 9 11 11 13 7 2 2 2 2 2 3 3 2 4 5 5 10 8 11 9 8 9 10 3 3 4 6 9 7 14 13 10 3 1 6 2 7 4 3 4 1 2 2 1 3 3 6 5 1 4 3 6 6 8 7 2 3 1 2 4 6 1 1 3 2 5 1 1 1 4 5 4 1 1 1 1 1 2 5 2 44 40 24 28 16 28 100 100 92 92 92 92 92 88 84 88 76 76 72 60 64 60 48 44 32 20 88 88 84 72 60 52 28 24 20 28 24 1.0 1.0 1.1 1.2 1.4 1.5 0.0 0.0 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.2 0.3 0.3 0.4 0.4 0.4 0.4 0.7 0.9 1.1 1.4 0.1 0.1 0.2 0.4 0.4 0.7 0.9 1.0 1.4 1.7 2.3 WATER MANAGEMENT TRIAL 25 BTX1544-2W/Y MSI049-AMRLBR 25 23 ATX91137-1RU MSJ317-1LBR 23 23 NDTX4271-5R NDTX4304-1R 23 23 Russet Norkotah 22 MSE192-8RUS MSJ080-1 21 MSJ461-1LBR 22 19 MSG227-2 19 Onaway CO089097-2R 18 15 Boulder 16 MSH228-6 Michigan Purple 15 12 MSJ147-1 11 Snowden 8 Atlantic MSE018-1 5 TRANSGENIC TRIAL SPG2 SPG3 Spunta L.ROSE5.2 L.ROSE5.6 L.ROSE5.1 Lady Rosetta L.ROSE5.4 L.ROSE5.3 Atlantic Newleaf Atlantic 22 22 21 18 15 13 7 6 5 7 6 48 ENTRY NUMBER OF SPOTS PER TUBER 0 5+ 1 4 2 3 PERCENT (%) BRUISE FREE AVERAGE SPOTS/TUBER SNACK FOOD ASSOCIATION: BRUISE SAMPLES MSJ461-1LBR 1 A91790-13 MSF099-3 Atlantic ND5822C-7 W1773-7 Snowden AF2211-9 WI201 B01240-1 NY132 ND2470-27 17 16 13 10 8 9 10 6 7 3 15 4 5 7 8 11 15 12 5 9 7 8 1 6 2 1 4 3 1 4 9 8 7 4 1 2 4 7 2 2 10 1 1 SNACK FOOD ASSOCIATION: CHECK SAMPLES MSJ461-1LBR A91790-13 MSF099-3 Snowden W1201 W1773-3 B01240-1 AF2211-9 ND2470-27 NY132 ND5822C-7 Atlantic 25 24 24 24 23 23 22 21 21 21 19 18 1 1 1 2 2 3 4 4 4 6 6 1 1 5 3 2 68 64 52 40 32 36 40 24 28 12 60 16 100 96 96 96 92 92 88 84 84 84 76 72 0.5 0.5 0.6 0.8 0.8 0.8 1.0 1.2 1.3 1.5 1.5 1.8 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.2 0.3 49 Federal Funding and MPIC Management Profile for New Potato Varieties and Lines December 2004 Sieg S. Snapp, Chris M. Long, Dave S. Douches and Kitty O’Neil (snapp@msu.edu) Department of Crop and Soil Sciences Michigan State University, East Lansing, Michigan USA 48824 Summary Varieties and promising new lines were tested systematically for response to four nitrogen regimes at moderate and high plant population densities. Environmental consequences in terms of residual soil nitrogen and nitrogen fertilizer efficiency were tested as well as yield response and tuber quality effects. Table 1 shows the sources of nitrogen fertility, including fertilizer and poultry manure. Variety determined yield and tuber quality response, where there were highly significant interactions with nitrogen regime and plant population density. Overall, a higher plant density (8 inch seed spacing within row) provided consistently higher yields for all varieties. The only exceptions were the control variety Snowden and the new release Michigan Purple. For these varieties yield of US No1 tubers was similar for both seed spacing treatments, narrow and wide (Fig. 2 and Fig. 6). For all other varieties, US No1 tubers yields were highest for the higher plant density treated with either the recommended rate of 180 lb N/acre fertilizer, or the same rate applied as 5000 lb/acre poultry manure plus 130 lb N per acre fertilizer (Fig. 3-5). Consistently lower tuber yields resulted from application of slow-release fertilizer at the 180 lb N/acre rate. This was, however, the most environmentally-friendly treatment associated with the lowest level of residual nitrate-N in the fall soil profile (Table 2). The poultry manure (50 lb N/acre available) + 130 lb N/acre fertilizer treatment was the best economic option. It both optimized yield and reduced nitrogen inefficiency, as indicated by the moderate residual inorganic soil nitrogen observed with the manure treatment (Table 2). The available nitrogen pool in the soil was moderately reduced with the manure and in the slow release nitrogen treatments, compared to the conventional 180 and 270 nitrogen treatments. This is indicated in Fig. 1, which presents the soil nitrate pool as measured by ion exchange probes inserted in the Snowden treatment. Interestingly, the manure + 130 lb N/acre treatment was highly efficient in that it supported maximum yields at moderate petiole N levels, while at the same time building soil organic matter (preliminary data from particulate organic matter nitrogen measurements). Consistently high yield responses among the chip processing genotypes were observed for the UEC variety (Fig. and the new line MSJ461-1, significantly higher than the standard check Snowden variety. Michigan Purple also showed high yield potential across all management regimes evaluated. Tuber quality was consistently high (Fig. 7), with W1201 the only variety with a trend towards higher internal defects than the other lines. 50 Federal Funding and MPIC Table 1. Seed piece spacing compared wide (13 inch) and narrow (8 inch), in factorial combination with nitrogen treatments shown. Mich Purple spacing was wider, 10 and 15 inch. 180 lbs. Conventional 180 lbs. Manure Slow-release Conventional 270 lbs Nitrogen Treatment 180 lbs. 250 35 250 35 250 35 350 - - - - - (pounds per acre) - - - - - Fertilizer or Amendment Potash (0-0-60, pre-plant) Phosphorus (at planting) Meister T102 (40% N, pre-plant) Poultry manure (50 lbs. N/A credit = availability is assumed as 50 lbs) Urea (46-0-0) - at planting – 13 May - at hilling – 28 May - 23 June - 18 July Total N Table 2. Residual soil NO3-N and NH4-N at two depths in Snowden plots managed 91 120 120 65 182 91 65 65 65 182 5000 (3.5%N) 91 182 with one of four nitrogen fertilization treatments. Different superscripts indicate significant difference (p≤.05) 250 35 91 163 163 163 268 Depth Nitrogen Treatment 0-8" 8-20” 180 Conventional 180 Manure 180 Slow Release 270 Conventional 180 Conventional 180 Manure 180 Slow Release 270 Conventional NO3-N (ppm soil) NH4-N (ppm soil) 27.35a 27.45a 33.45ab 46.03b p=.0962 11.35a 13.10ab 12.23a 18.35b p=.0918 3.20 4.30 3.40 3.33 p=.5426 1.33 1.83 1.48 1.20 p=.4848 51 ) m p p ( d e b r o s d A e a r t i t N Federal Funding and MPIC Ion-Exchange Probe Nitrate Snowden Variety 180 Conventional 180 Manure 180 Slow 270 Conventional 80 70 60 50 40 30 20 10 0 50 60 70 80 90 100 110 Days ater Planting Fig. 1. Ion exchange probe inorganic nitrogen measurement indicate soil nitrogen availability for plant uptake. Snowden 8" 13" 500 450 400 350 300 250 200 150 100 50 0 ) A / t w c ( s r e b u t 1 . o N S U f o d e Y i l 180 Conv 180 Manure 180 Slow 270 Conv Nitrogen Source Fig. 2. Snowden ‘check’ response in 2004 to four nitrogen treatments and two seed spacing treatments, narrow (8” within row) and wide (13” within row). 52 Federal Funding and MPIC UEC N regime by spacing04 A / t w c 1 . o N S U 450 400 350 300 250 200 150 100 50 0 Narrow Wide 180Conv 180Slow 270Conv Manure Fig. 3. Yield response of variety UEC in 2004 to four nitrogen treatments and two seed spacing treatments, narrow (8” within row) and wide (13” within row). MSJ461-1 ) A / t w c ( 1 . o N S U 500 450 400 350 300 250 200 150 100 50 0 Narrow Wide 180Conv 180Slow 270Conv Manure Fig. 4. Yield response of variety MSJ461-1 in 2004 to four nitrogen treatments and two seed spacing treatments, narrow (8” within row) and wide (13” within row). 53 Federal Funding and MPIC FL1922 A / t w c 1 . o N S U 400 350 300 250 200 150 100 50 0 Narrow Wide 180Conv 180Slow 270Conv Manure Fig. 5. Yield response of variety FL1922 in 2004 to four nitrogen treatments and two seed spacing treatments, narrow (8” within row) and wide (13” within row). Michigan Purple ) A / t w c ( s r e b u t 1 . o N S U f o d e Y l i 500 450 400 350 300 250 200 150 100 50 0 5" 8" 180 Conv 180 Manure 180 Slow 270 Conv Nitrogen Source Fig. 6. Yield response of variety Michigan Purple in 2004 to four nitrogen treatments and two seed spacing treatments, narrow (8” within row) and wide (13” within row). 54 Federal Funding and MPIC Chip Quality s t c e f e D % / g n i d a e R n o r t g A 70 60 50 40 30 20 10 0 Defects Agtron FL1922 MSJ461-1 Snowden UEC W1201 Fig. 7. Chip quality as measured by internal defects and Agtron rating for five chip processing varieties and lines. 55 Funding: Federal Grant, MPIC and USPB/SFA 2004 On-Farm Potato Variety Trials Chris Long, Dr. Dave Douches, Fred Springborn (Montcalm), Dave Glenn (Presque Isle), and Dr. Doo-Hong Min (Upper Peninsula) Introduction On-farm potato variety trials were conducted with 11 farms in 2004 at a total of 12 locations. Seven of the locations evaluated processing entries and five evaluated fresh market entries. The processing cooperators were Crooks Farms, Inc. (St. Joseph / Montcalm) counties, L. Walther & Sons, Inc. (St. Joseph), Lennard Ag. Co. (Monroe), 4- L Farms, Inc. (Allegan), and Main Farms (Montcalm). The United States Potato Board/Snack Food Association (USPB / SFA) chip trial was at V & G Farms (Montcalm). Fresh market trial cooperators were Crawford Farms, Inc. (Montcalm), DuRussel’s Potato Farms, Inc. (Washtenaw), Wilk Farms (Presque Isle), Horkey Bros. (Monroe) and M.J. Van Damme Farms (Marquette). Procedure There were two types of processing trials conducted this year. The first type contained 12 entries which were compared with check varieties Atlantic, Snowden, Pike and FL1879. This trial type was conducted at Main Farms, Lennard Ag. Co., 4-L Farms, and Walthers Farms, Inc. 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 four replicated plots and harvested at two harvest dates of 115 and 158 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 five to seven lines which were compared to the variety in the field. In these trials each variety was planted in a 15’ row plot. Seed spacing and row width was 10” and 34”, respectively. Within the fresh market trials, there were 24 entries evaluated. There were 10-20 lines planted at each of the following locations; 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 7.5 to 12.25 inches depending upon grower production practices and variety. 56 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 Walther Farms, Inc. in St. Joseph County is shown separately in Table 3 (first harvest, 115 days) and Table 4 (second harvest, 158 days). The overall averages of the “Select” processing trial, which are averaged across two locations, are in Table 5. Processing Variety Highlights MSG227-2, a scab resistant clone from the Michigan State University (MSU) breeding program, had the third highest yield across all locations (Table 2). This variety had a good yield, acceptable specific gravity and superior scab resistance. Nearly 100 acres of MSG227-2 will be planted commercially in 2005. W1201 (Megachip) a University of Wisconsin release continues to show promise as a strong yielding, high specific gravity, line. There are plans to plant 60 acres commercially of this variety in Michigan in 2005. The variety bulks early and has low internal defect and possibly could be used for fresh crop. Megachip has shown some susceptibility to black spot bruise, possibly due to its high specific gravity. FL1922, a scab resistant Frito-Lay, Inc. release, has excellent processing quality but, unlike commercial results, we have been unable to show its yield potential in these trials. UEC, now “Beacon Chipper”, was only in the Walther Farms, St. Joe County data (Table 3 & 4) and Crooks Montcalm County trial (data not shown). This variety continues to perform well agronomically and has proven to store well in storage trials conducted at the Burt Cargill Demonstration Storage facility. MSJ147-1, another Michigan State clone, was a strong yielding line with good internal quality, excellent chip quality and a slight tolerance to common scab. This variety may be suitable for storage into May and June. Two varieties that were in the Crooks Farms “Select” trials and are showing some promise for further large scale evaluations are W2128-8 from the University of Wisconsin and MSJ036-A from MSU. W2128-8 has excellent chip quality and yield potential and MSJ036-A has good chip quality, very nice uniform type and excellent common scab resistance. B. USPB / SFA Chip Trial Results The Michigan location of the USPB / SFA chip trial was on the V & G Farm in Montcalm county again this year. 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 Herr Foods, Inc., Nottingham, PA. 57 USPB / SFA Chip Trial Highlights The variety in the 2004 trial that has displayed the greatest potential for commercialization was W1201 (Megachip). Yield potential and specific gravity are excellent. Internal quality of Megachip was also good. The potential for this variety to bulk early in spite of its full season maturity was excellent. The variety can exhibit deep apical eyes at times and given soil conditions, may not be a desirable trait. Megachip has shown severe black spot bruise when cold harvested. This condition may be heightened by the varieties high specific gravity. C. Fresh Market and 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 five locations; Marquette, Monroe, Montcalm, Presque Isle and Washtenaw counties. Fresh Market Variety Highlights Three russet lines are worthy of mention from the 2004 variety trial. They are MSA8254-2BRus, Gemstar Russet (A9014-2Rus) and Stampede Russet. MSA8254-2BRus has an unknown pedigree with excellent scab resistance (Table 8). MSA8254-2BRus had a 436 cwt./A US#1 yield with a 1.078 specific gravity. This variety has a nice long type. Gemstar Russet is a University of Idaho selection with a 412 cwt./A US#1 yield. It’s specific gravity was 1.078. The long type of this variety was very uniform and attractive overall. Stampede Russet is a Texas A&M selection that has an excellent table stock russet type. The overall yield of this variety appears to be low, but it has exceptional tuber type and internal quality. More testing of this clone needs to be done to manipulate yield, possibly with a change in seed spacing and/or fertilizer levels. MSJ461-1 is a foliar late blight resistant, round white variety from the MSU breeding program. This variety continues to be a strong yielding variety with an attractive appearance. This variety has a two year US#1 yield average of 444 cwt./A. The specific gravity is generally in the 1.075 to 1.080 range. MSJ461-1 is susceptible to common scab. ND3196-1R (Dakota Jewel) is a North Dakota State University release with a nice round type and an attractive red skin. Yield of this variety is generally around 300 cwt./A with an attractive marketable appearance. The flesh color of this variety is very white and uniform. MSJ033-10Y is an MSU clone with an average yield, exceptionally nice yellow flesh. Skin appearance is slightly netted with good internal quality. 58 Table 1 2004 MSU Processing Potato Variety Trials Entry Characteristics Pedigree 2003 Scab Rating** Atlantic (B6987-56) FL1879 FL1922 Monticello (NY102 or K9-29) Pike (NYE55-35) Snowden (W855) AF2211-9 Wauseon X Lenape Snowden X FL1207 - Steuben X Kanona Allegany X Atlantic B5141-6 X Wischip Atlantic X Maine Chip B0766-3 B0243-18 X B9792- 157 (Coastal Chip) 3.0 2.5 1.3 3.0 1.5 2.4 - 1.5 Early maturing, high yield check variety. Late maturing, late season storage check variety. Oval to oblong tubers, good chip quality out of late storage. Mid-season maturity, average yield, high specific gravity, good storability, low internal defects. Early maturing, early storage check variety. Late maturing, late season storage check variety. Mid-season maturity, high specific gravity, moderate scab tolerance, good tuber appearance, cold chipping potential, high yield. Mid-season maturity, high yield, uniform size, scab tolerant, round to oval shape, good chip quality until early March from 50 ºF. Average yield potential: flattened round shape, shallow eyes, low internal defects, chip color variable in storage. Mid-season maturity, smooth flat oval tubers, some hollow heart may be observed. Mid-season maturity, bruise susceptibility equal to Snowden. Mid-season maturity, slightly flattened tubers, shallow eyes, intermediate specific gravity. Mid-season maturity, high yield, nice round uniform tuber type. MSG227-2 Prestile X MSC127-3 0.5 MSH067-3 MSC127-3 X W877 MSH095-4 MSE266-2 OP MSH228-6 MSC127-3 OP MSJ036-A A7961-1 X Zarevo 2.0 1.7 0.7 1.3 **Scab rating based on 0-5 scale; 0 = most resistant and 5 = most susceptible. 59 Characteristics Entry MSJ080-1 Pedigree MSC148-A X S440 2003 Scab Rating** 2.0 MSJ147-1 Norvalley X S440 MSJ461-1 Tollocan X NY88 MSK061-4 MSC148-A X Dakota Pearl UEC* Unknown W1201 Wischip X FYF 85 W1773-7 Steuben X RHL167 W2128-8 W845 X CT80-1 W2133-1 Snowden X RHL 167 W2154-1 W936 X CT114-10 1.7 2.7 2.0 1.3 1.7 1.7 - - - Mid-season maturity, yield similar to Atlantic, low internal defects, intermediate specific gravity, smooth tuber type. Mid-season maturity, good internal quality, very good chip quality. Maturity slightly earlier than Snowden, round tubers with bright skin, low defects, strong foliar late blight resistance, chipped well 2003 Demo Storage, intermediate specific gravity. Medium to late season maturity, high specific gravity, good chip color. Mid-season maturity, high yield, some heat stress and scab tolerance. Late maturing, high yield, cold chipper 45 °F, slightly deep eyes. Mid-season maturity, medium to low specific gravity, round, smooth tubers, excellent internal quality, good chip color after 3 months at 48 ºF. Medium late maturity, slight deep eye, good size, high specific gravity, cold chipper, moderate scab tolerance. Medium late maturity, scab resistant, good internal quality, good yield, nice tuber type, average specific gravity. Medium late maturity, good size, medium flat tubers, bruise susceptible, good yield and internal quality. **Scab rating based on 0-5 scale; 0 = most resistant and 5 = most susceptible. *Unknown Eastern Chipper (UEC), now “Beacon Chipper”, was previously tested and labeled as the clone B0766-3 in the 2001-2002 Michigan “On-Farm Variety Trials”. B0766-3, a USDA Beltsville potato clone from Dr. Kathleen Haynes’ Breeding Program, Beltsville, Maryland is being considered for release. The official seed source for B0766-3 is the Uihlein Seed Farm, NY. The two clones UEC and B0766-3 have undergone fingerprint analysis at Michigan State University and the pattern of B0766-3 does not match that of UEC. Thus, the UEC clone tested was incorrectly referred to as B0766-3. No known variety or breeding clone matches the UEC fingerprint pattern to date. The origin and pedigree of UEC is currently unknown. UEC seed that is represented in this summary was obtained from Devoe Seed Farm, Limestone, ME. The initial seed stock was obtained from the Maine State Seed Farm which is the Porter Seed Farm. The Michigan State University fingerprint data of UEC shows an identical match between the Devoe Farm seed and the tissue culture plantlets at the Porter Seed Farm from which all the seed labeled as UEC has been derived. 60 Table 2 2004 Processing Potato Variety Trial Overall Average - Three Locations Allegan, Monroe, Montcalm Counties 3-YR AVG LINE MSJ080-1 FL1879 MSG227-2 MSJ147-1 MSJ461-1 MSH228-6 Snowden W1201 W1773-7 B0766-3 Atlantic MSH095-4 Pike MSH067-3 AF2211-9 FL1922 MEAN CWT/A US#1 446 411 410 405 392 392 386 386 386 346 346 330 275 273 273 170 325 TOTAL 486 434 462 437 430 430 429 424 446 388 376 349 302 306 313 218 355 US#1 92 95 89 92 91 91 90 91 86 89 92 94 90 89 86 78 89 PERCENT OF TOTAL1 OV Bs 17 8 5 18 6 7 10 7 6 8 6 21 7 10 24 4 5 13 10 10 8 19 28 4 6 8 19 8 7 13 19 1 As 75 76 83 83 85 70 83 67 81 79 73 67 85 70 79 77 PO 0 0 4 1 1 3 0 5 1 1 0 1 1 3 1 3 CHIP SP GR SCORE3 1.074 1.076 1.084 1.082 1.075 1.080 1.083 1.090 1.089 1.081 1.089 1.078 1.086 1.082 1.081 1.072 1.083 1.0 1.0 1.2 1.0 1.0 1.0 1.0 1.0 1.0 1.2 1.0 1.0 1.0 1.0 1.0 1.0 TUBER QUALITY2 VD 0 2 1 1 1 3 3 2 0 1 1 2 2 1 0 1 IBS 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 HH 1 1 1 0 1 1 0 0 1 1 2 0 1 3 2 0 TOTAL CUT 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 COMMENTS Tr surface scab Sl pitted scab No scab Surface scab Sl pitted scab Sl surface scab Scab Surface scab Surface scab Surface scab Pitted scab Sl pitted scab Tr surface scab Sl pitted scab, round to flat Pitted scab Tr surface scab BC 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 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 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 sl = (slight) tr = (trace) US#1 CWT/A - - 353 - *365 - 334 362 - - 362 326 242 - - - 61 Table 3 2004 Processing Potato Variety Trial L. Walther & Sons, Inc. (Three Rivers, MI) First Harvest1 August 26, 2004 ( 115 Days) PERCENT OF TOTAL2 US#1 Large CWT/A US#1 626 610 570 519 499 492 483 479 476 473 464 456 414 411 391 372 350 344 468 TOTAL 655 632 608 571 513 514 521 484 534 508 489 481 449 445 404 387 362 353 495 LINE ND5822C-7 FL1879 MSJ080-1 MSG227-2 W1201 B0766-3 W1773-7 UEC MSJ461-1 Snowden Atlantic MSH228-6 MSJ147-1 MSH067-3 AF2211-9 FL1922 Pike MSH095-4 AVERAGE As 95 97 94 91 97 96 93 99 89 93 95 95 92 92 97 96 97 97 95 Bs 5 3 6 9 3 4 7 1 11 7 5 5 8 8 3 4 3 3 5 Small As 95 97 94 91 97 96 93 98 89 93 94 95 92 92 97 96 97 97 95 Total Chip Defects4 17.9 15.3 6.5 4.3 2.4 29.9 0.0 14.6 0.0 4.9 15.4 0.0 2.2 0.0 23.8 4.8 0.0 4.6 SP GR 1.085 1.087 1.078 1.092 1.093 1.088 1.098 1.088 1.084 1.087 1.090 1.088 1.089 1.090 1.091 1.083 1.090 1.091 1.088 HH3 1.5 0.3 1.5 2.5 0.0 2.0 0.3 2.8 0.0 0.5 3.0 1.8 0.0 2.0 4.3 0.5 0.3 0.5 As 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 1All data presented is based on an average of four replications 2Percent of Total (Size) US#1: 2 - 4 in. Large As: >4 in. Small As: 2 - 4 in. Bs: < 2 in. 3Based on a 10 tuber raw sample 4Total Chip Defects are comprised of; undesirable color, greening, internal defects and external defects, present in one replication. Planted May 3, 2004 9" seed spacing Vine Kill: None 62 Table 4 2004 Processing Potato Variety Trial L. Walther & Sons, Inc. (Three Rivers, MI) Second Harvest1 October 8, 2004 ( 158 Days) PERCENT OF TOTAL2 Large Total Chip Defects4 17.8 24.7 25.1 31.2 1.4 12.7 2.4 11.2 22.1 0.0 10.9 0.0 12.7 13.3 0.0 3.9 0.0 7.4 SP GR 1.087 1.086 1.093 1.088 1.090 1.086 1.086 1.086 1.089 1.085 1.079 1.081 1.083 1.082 1.091 1.090 1.090 1.090 1.087 HH3 1.8 2.8 0.8 0.0 0.0 2.3 1.3 0.8 2.3 0.3 0.0 0.3 1.0 0.5 0.0 0.3 1.5 2.8 As 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 CWT/A US#1 789 656 641 620 615 589 584 564 543 538 523 492 446 441 420 410 405 379 536 TOTAL 841 687 702 666 671 615 651 671 589 589 564 533 461 538 482 451 420 431 587 LINE ND5822C-7 B0766-3 W1773-7 W1201 MSJ080-1 MSH228-6 FL1879 MSG227-2 Atlantic MSJ147-1 Snowden FL1922 UEC MSJ461-1 MSH095-4 Pike MSH067-3 AF2211-9 AVERAGE US#1 As 94 96 91 93 92 96 90 84 92 91 93 92 97 82 87 91 96 88 91 Bs 6 4 9 7 8 4 10 16 8 9 7 8 3 18 13 9 4 12 9 Small As 94 96 91 93 92 96 90 84 92 91 93 92 97 82 87 91 96 88 91 1All data presented is based on an average of four replications 2Percent of Total (Size) US#1: 2 - 4 in. Large As: >4 in. Small As: 2 - 4 in. Bs: < 2 in. 3Based on a 10 tuber raw sample 4Total Chip Defects are comprised of; undesirable color, greening, internal defects and external defects, present in one replication. Planted May 3, 2004 9" seed spacing Vine Kill: September 15, 2004 (135 Days) 63 Table 5 NUMBER OF LOCATIONS 2 2 2 2 2 LINE W2128-8 MSH228-6 W1201 MSJ036-A W2154-1 MEAN 2004 "Select" Processing Potato Variety Trial Overall Average - Crooks Farms, Inc., Two Counties Montcalm & St. Joseph Counties CWT/A TOTAL US#1 560 456 422 414 391 449 603 487 445 468 453 491 PERCENT OF TOTAL1 OV Bs 9 5 7 5 4 7 2 11 11 1 As 84 86 88 87 85 US#1 93 94 95 88 87 91 PO 2 1 1 1 2 SP GR 1.097 1.086 1.092 1.087 1.092 1.091 HH 0 1 0 0 1 TUBER QUALITY2 VD 0 0 0 1 0 IBS 0 0 1 0 0 TOTAL CUT 10 10 10 10 10 BC 0 0 0 1 0 COMMENTS Sl surface scab, flat and oblong Tr raised scab, flat and round Sl surface scab, sheep nose Tr raised scab, nice size, uniform Tr pitted scab, not uniform type 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 sl = (slight) tr = (trace) 64 Table 6 USPB / SFA Potato Variety Trial V & G Farms, Montcalm County, MI October 4, 2004 (154 DAYS) LINE MEAN ND5822C-7 A91790-13 W1201 B01240-1 MSJ461-1 SNOWDEN ATLANTIC ND2470-27 MSF099-3 W1773-7 NY132 AF2211-9 CWT/A US#1 673 490 488 487 441 416 415 408 391 384 353 324 439 TOTAL 705 543 504 526 484 438 431 426 431 421 361 360 469 US#1 95 90 97 93 91 95 96 96 91 91 98 90 94 PERCENT OF TOTAL1 OV Bs 3 25 5 9 17 3 28 3 8 7 15 4 8 3 35 3 3 9 9 9 23 2 9 1 As 70 85 80 64 84 80 88 61 82 82 75 89 PO 2 1 0 5 1 1 0 1 6 0 0 1 CHIP SP GR SCORE3 1.085 1.090 1.091 1.084 1.079 1.087 1.093 1.078 1.083 1.087 1.089 1.085 1.086 1.5 1.0 1.0 1.5 1.0 1.0 1.0 1.0 1.0 2.0 1.0 1.0 TUBER QUALITY2 VD 1 3 7 3 1 11 3 12 1 0 1 8 IBS 0 1 0 0 2 0 0 1 0 0 0 0 TOTAL CUT 30 30 30 30 30 30 30 30 30 30 30 30 SCAB4 nd nd nd nd 1.8 1.9 2.1 nd 2.5 1.8 1.5 2.3 BC 12 0 0 1 0 0 0 1 1 0 0 0 HH 14 0 0 2 2 2 2 3 8 6 4 0 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 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 nd = no data Planted: April 30, 2004 Seed Spacing : 9" Vine Kill Date: None 65 Table 7 SFA / USPB Potato Variety Trial Post Harvest Chip Quality Evaluation1 Percent Chip Defects Internal External Total Agtron Color 65.4 63.8 61.7 62.2 66.1 62.6 61.8 63.0 62.0 62.1 67.7 68.3 SFA2 Color 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.5 1.0 1.0 Specific Gravity 1.082 1.085 1.089 1.080 1.073 1.082 1.085 1.077 1.079 1.082 1.088 1.083 Entry ND5822C-7 A91790-13 5 3 1 24 1 10 7 2 0 5 0 2 1Samples collected at harvest October 4 and processed by Herr Foods Inc., Nottingham, PA on October 14, 2004 (11 days). 2SFA Color: 1 = lightest, 5 = darkest. W1201 B01240-1 MSJ461-1 SNOWDEN ATLANTIC ND2470-27 MSF099-3 W1773-7 NY132 AF2211-9 1 3 0 1 0 1 2 0 0 0 3 0 6 6 1 25 1 11 9 2 0 5 3 2 66 Table 8. 2004 MSU Freshpack Potato Variety Trials Characteristics Pedigree Entry 2003 Scab Rating* Boulder (MSF373-8) Dakota Jewel (ND3196-1R) MS702-80 X NY88 ND2223-8R X ND649-4R Dakota Pearl (ND2676-10) ND1118-1 X ND944-6 Eva (NY103) Steuben X OP Goldrush (ND1538-1 Rus) Katahdin (USDA 42667) Keuka Gold (NY101) ND450-3 Rus X Lemhi Russet USDA 40568 X USDA 24642 Steuben X Norwis Keystone Russet (AC83064-1) CalWhite X A7875-5 0.5 Marcy (NY112) Atlantic X Q155-3 Michigan Purple W870 X Maris Piper Millennium Russet (W1348 Rus) Onaway Atlantic X FL1154 Rus USDA X96-56 X Katahdin 2.0 1.0 1.0 2.8 0.3 - 1.0 1.8 3.0 1.0 1.7 High yield, large tubers, low internal defects, med. deep eyes. Early maturity, average yield, smooth round tubers, white flesh, shallow eyes, stores well, some brown center noted, nice red color out of the field. Early maturing, low internal defects, average yield, cold chipping potential at 42 °F. Mid-season maturity, above average yield, round to oval appearance, resistant to PVX and PVY. Long to oval tubers, heavy russet, check variety. Mid-season maturity, high yielding check variety. Full season maturity, high yield, pale yellow flesh, round to oval shape. Susceptible to internal heat necrosis. Medium-late maturity, high yield, good storability, good internals, resistant to black spot, short dormancy. Full season maturity, high yield, smooth round appearance. Mid-season, attractive purple skin, white flesh, high yield potential, low incidence of internal defects. Full season, dual purpose, medium to high specific gravity, moderate scab resistance, medium to long dormancy. Early maturing, high yielding check variety. *Scab rating based on a 0-5 rating; 0 = most resistant and 5 = most susceptible. 67 Characteristics High yield, bright tubers, low incidence of internal defects, mid to late season maturity. Mid-season maturity, average yield, long to oval tubers, heavy russet, check variety. Oblong to long, medium russet skin, medium yield, masks PVY. Early season maturity, oblong to long, heavy russeting, average yield potential, fresh market. Late season maturity, dual purpose, good dormancy, high Entry Reba (NY 87) Pedigree Monona X Allegany 2003 Scab Rating* 2.5 Russet Norkotah (ND534-4 Rus) ND9526-4 Rus X ND9687-5 Rus Silverton Russet (A083064-6) A76147-2 X A7875-5 Stampede Russet (TXAV657-27Rus) A9014-2Rus Rio Grande Russet AC89536-5 Rus BR7091-1 X Lemhi Russet Gem Russet X A8341-5 Butte X A8469-5 MSA8254- 2BRus MSE192-8 Rus Unknown A81163 X Russet Norkotah MSH031-5 MSB110-3 X MSC108-3 MSI005-20Y MSA097-1Y X Penta MSJ033-10Y A097-1 X Penta MSJ461-1 Tollocan X NY88 2.5 0.0 0.3 1.0 0.0 0.0 1.2 2.7 1.5 1.0 2.7 specific gravity. Mid-season maturity, high yielding, average gravity, dormancy similar to R. Norkotah. Late season maturity, dual purpose, medium specific gravity, good yield. Long russet tubers, low internal defects, bright white flesh, good cooking quality, specific gravity similar to R. Norkotah, PVY expression good. Mid-season maturity, average yield, nice appearance, res. to black spot. Early to mid-season maturity, high yielding, low internal defects, strong yellow flesh color. Mid-season maturity, strong yellow flesh color, good size profile, nice round type. Maturity slightly earlier than Snowden, round, bright skin, low defects, strong foliar late blight resistance, nice flavor, intermediate specific gravity. *Scab rating based on a 0-5 rating; 0 = most resistant and 5 = most susceptible. 68 Table 9 2004 Freshpack Potato Variety Trial Overall Averages - Five Locations Marquette, Monroe, Montcalm, Presque Isle, Washtenaw Counties 3-YR AVG NUMBER OF LOCATIONS 4 3 5 5 3 5 3 5 4 3 3 3 2 5 2 3 5 2 3 3 2 4 3 LINE Satina Onaway Keuka Gold Marcy Reba MSJ461-1 MSA8254-2BRus MSI005-20Y A9014-2Rus AC89536-5Rus Michigan Purple Keystone Russet Silverton Russet MSH031-5 Russet Norkotah Millennium Russet MSJ033-10Y Eva Stampede Russet ND3196-1R Goldrush Dakota Pearl MSE192-8Rus MEAN CWT/A TOTAL US#1 545 529 518 505 467 466 436 431 412 404 398 397 386 386 377 370 366 351 323 301 301 273 200 397 610 574 540 534 489 526 528 474 467 531 438 476 451 428 435 511 421 384 387 342 409 338 305 461 PERCENT OF TOTAL1 OV Bs 15 5 3 20 25 3 23 5 24 5 17 9 19 12 8 15 15 9 8 21 26 7 16 16 12 20 3 10 30 15 3 26 13 11 4 23 13 18 17 8 13 22 1 19 30 5 As 74 71 71 71 70 73 63 75 72 66 64 65 66 86 56 68 74 69 69 70 60 78 60 US#1 89 91 96 94 95 89 82 90 87 74 90 82 86 89 85 71 87 92 81 87 73 80 65 85 PO 6 6 1 1 1 2 5 2 4 4 3 2 2 1 1 3 2 5 1 5 5 1 4 SP GR 1.070 1.071 1.072 1.076 1.073 1.076 1.078 1.067 1.078 1.080 1.076 1.068 1.077 1.076 1.072 1.087 1.068 1.064 1.061 1.072 1.080 1.072 1.069 1.073 HH 0 0 1 1 2 1 3 0 3 3 0 2 0 0 5 2 0 0 0 3 0 0 0 TUBER QUALITY2 VD 0 0 0 0 0 0 0 0 1 0 0 1 2 0 0 0 0 0 0 0 1 0 1 IBS 2 0 2 1 0 1 0 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 TOTAL CUT 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 COMMENTS Surface scab, knobs, points Sheep nose, knobs, surface scab Uniform type, sl scab, yellow flesh Uniform type, netted skin Scab Long type Nice yellow flesh, knobs, sl scab Long type, tr scab, heavy russet Heavy russet skin, long type Scab Blocky to oval, light russet skin Bright appearance, scab, flat to oval Heavy russet skin, long type Growth crack, nice uniform type Heavy russet skin, long type Very white flesh color, good skin set Nice bright appearance, small size Heavy russet skin, long type BC 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 US#1 CWT/A - 381 457* 478* 397 444* 378* - - 309* 355 385 305 361 274 - - 316* - 274* - 275 195 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 sl = (slight) tr = (trace) 69 Seed treatments, in-furrow and seed plus foliar treatments for control of potato stem canker and black scurf, 2004. W. W. Kirk, R. L Schafer, D. Berry, P. Wharton and P. Tumbalam. Department of Plant Pathology, Michigan State University, East Lansing, MI 48824 Introduction Funding: MPIC, MSU and Industry Stem canker and black scurf of potatoes is caused by the pathogen Rhizoctonia solani (AG-3). Rhizoctonia disease is initiated by seedborne or soilborne inoculum. Seedborne inoculum is carried on seed tubers in the form of sclerotia (black scurf) or as mycelium from the previous season. When contaminated seed is planted the fungus grows from the seed surface to the developing sprout and infection of root primordia, stolon primordia and leaf primordia can occur. The sprouts can be killed at this stage and emergence may be prevented or delayed. Mycelia and sclerotia of R. solani also survive in soil and on plant debris and can cause disease independently of seedborne inoculum. Soilborne inoculum can infect potato tissue at anytime when plant organs develop in the proximity of inoculum however the plant is most severely impacted when immature sprouts, stolons and roots are infected early in the season. However, as growers in Michigan are constrained by season length and rotation requirements it is necessary to include the application of fungicides effective against R. solani in a control program. Trials at MSU and elsewhere have indicated that there are several effective fungicides that can be used to manage R. solani, either applied as seed treatments or as in-furrow at-planting applications. These fungicides include fludioxonil-based seed treatments (Maxim products), strobilurin- based products applied in-furrow [azoxystrobin (Quadris, Amistar)], and flutolonil-based fungicides [Moncoat MZ (seed treatment); Moncut (in-furrow)]. Although products are available, new standards are being developed for avoidance of resistance in pathogen populations (not necessarily R. solani) to at- risk fungicide classes such as those in group 11 [QoI-fungicides (Quinone outside Inhibitors)] which includes all the strobilurins currently registered for use on potatoes. The broad spectrum of efficacy reported in strobilurins may lead to excessive use in the future as other products such as B2 carcinogens are at risk of further limitations in usage, and therefore a management plan for their use need to be developed which is compatible with potato production in Michigan. Currently there are many fungicidal options available for control of Rhizoctonia diseases of potato and the objectives of this project therefore are to identify the efficacy of some fungicides applied as seed treatments or as in-furrow at-planting applications against the Rhizoctonia diseases, stem canker and black scurf of potatoes. Methods and materials 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 Muck Soils Experimental Station, Bath, MI on 28 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 5-ft unplanted row. Dust formulations were measured and added to cut seed pieces in a Gustafson revolving drum seed treater and mixed for 2 min 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 psi) 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 70 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 23 DAP. 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 43 DAP (about 100% canopy closure), (max = 100). Severity of stem canker was estimated as the percentage of stems per plant with greater than 10% girdling caused by R. solani, measured 43 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 13 Sep). Plots (25-ft row) were harvested on 5 Oct and individual treatments were weighed and graded. Samples of 50 tubers per plot were harvested 21 days after desiccation (99 DAP). Tubers were washed and assessed for black scurf (R. solani) incidence (%) and severity 50 days after harvest on 2 Nov. 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 > 15% 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. Maximum and minimum air temperature (oF) were 88.2 and 67.2 (Jun), 87.5 and 67.7 (Jul), 88.1 and 67.7 (Aug) and 85.3 and 66.0 (Sep). Maximum and minimum soil temperature (oF) were 74.5 and 69.8 (Jun), 77.0 and 71.9 (Jul), 78.0 and 71.4 (Aug) and 75.9 and 70.2 (Sep). Maximum and minimum soil moisture (% of field capacity) was 98.5 and 95.8 (Jun, severe flooding); 98.1 and 63.3 (Jul), 85.4 and 71.4 (Aug) and 76.8 and 79.8 (Sep). Precipitation was 4.04” (Jun), 3.68" (Jul), 1.83" (Aug) and 0.93" (Sep). No seed treatment (ST) or fungicide applied at planting in-furrow (IF) was significantly different from the untreated control or from the Moncoat MZ 0.5 lb (ST) commercial standard treatment in terms of the final plant stand. No seed treatment (ST) or fungicide applied at planting in-furrow (IF) was significantly different from the untreated control or from the Moncoat MZ 0.5 lb (ST) commercial standard treatment in terms of rate of emergence (RAUEPC). No seed treatment (ST) or fungicide applied at planting in-furrow (IF) was significantly different from the untreated control or from the Moncoat MZ 0.5 lb (ST) commercial standard treatment in terms of the rate of canopy formation (RAUCPC) except treatment 4. All treatments significantly reduced the percentage of stolons with greater than 5% girdling due to R. solani in comparison with the untreated control but there was no difference among treatments. All treatments significantly reduced the percent incidence of black scurf on tubers in comparison with the untreated control except treatment 1. There was no significant difference among treatments with 16.3 - 48.8%; 37.5 - 75.0%; and 75.0 - 96.3% incidence of tuber black scurf. All treatments significantly reduced the severity of black scurf on tubers in comparison with the untreated control except treatment 1 measured as an index on the 0 - 100 scale. There was no significant difference in the index of severity of black scurf between treatments with indices between 5.0 and 25.3; 20.0 to 42.2 and from 42.2 to 48.4. Treatments with marketable yield between 246 (non-treated control) and 312 cwt/A; and 273 and 340 cwt/A were not significantly different. There were no significant differences among treatments in total yield. 71 (RAUCPC)x abw ab a a Canopy development 23 days after planting Emergence (RAUEPC)y 97.0 98.0 100.0 100.0 Plant number (%) emerged Amistar 80WDG 0.12 oz/1000 ft Table 1. Effect of seed treatments and in-furrow at-planting applied treatments on emergence, canopy development and stem and stolon canker and black scurf incidence and severity on potatoes at the Muck Soils Research Farm, 2004. Treatment and rate/cwt (seed treatment) rate/A (in furrow)z 1 Potato Seed Treater PS 8% 1.0 lb ST........ IF......... 2 Moncut 70DF 0.79 oz/1000 ft IF......... 3 Moncut 70DF 1.18 oz/1000 ft 4 Maxim 4 FS 0.08 fl oz ST........ ST 5 Maxim 4 FS 0.08 fl oz + IF......... ST........ ST IF........ ST IF......... ST IF......... ST........ IF......... ST........ ST Foliar... NA...... 10 Tops MZ 0.75 lb 11 Amistar 80WDG 0.12 oz/1000 ft 12 Headsup 3WDG 0.1 lb 13 Headsup 3WDG 0.1 lb + Quadris 2.08SC 0.05 fl oz/1000 ft 8 Potato Seed Treater PS 8% 1.0 lb + 9 Potato Seed Treater PS 8% 1.0 lb + Headline 2.09SC 0.05 fl oz/1000 ft 6 Moncoat MZ 0.75 lb 7 Maxim 4 FS 0.08 fl oz + Amistar 80WDG 0.12 oz/1000 ft Headsup 3WDG 0.1 lb abc ab ab abcd ab ab ab ab a ab 97.5 96.0 98.0 98.5 0.26 0.27 0.27 0.24 ab ab a bcd a abc 0.18 0.18 0.18 0.16 0.27 0.26 0.26 0.27 0.18 0.18 0.19 0.13 0.19 0.17 0.28 0.26 0.29 0.25 ab ab ab ab a a 100.0 100.0 ab a ab abc a ab a ab a a 0.19 0.19 a a 0.18 0.18 ab ab 100.0 100.0 0.28 0.26 99.5 98.0 a ab 14 Untreated Amistar 80WDG 0.12 oz/1000 ft 6 Moncoat MZ 0.75 lb 7 Maxim 4 FS 0.08 fl oz + Treatment and rate/cwt (seed treatment) rate/A (in furrow)z 1 Potato Seed Treater PS 8% 1.0 lb ST........ 2 Moncut 70DF 0.79 oz/1000 ft IF......... IF......... 3 Moncut 70DF 1.18 oz/1000 ft ST........ 4 Maxim 4 FS 0.08 fl oz ST 5 Maxim 4 FS 0.08 fl oz + IF........ ST........ ST IF......... ST IF......... ST IF....... ST........ IF......... ST....... ST Foliar.. NA...... 10 Tops MZ 0.75 lb 11 Amistar 80WDG 0.12 oz/1000 ft 12 Headsup 3WDG 0.1 lb 13 Headsup 3WDG 0.1 lb + Quadris 2.08SC 0.05 fl oz/1000 ft 8 Potato Seed Treater PS 8% 1.0 lb + 9 Potato Seed Treater PS 8% 1.0 lb + Headline 2.09SC 0.05 fl oz/1000 ft Amistar 80WDG 0.12 oz/1000 ft Headsup 3WDG 0.1 lb Percent stolons with greater than 10% girdling due to R. solaniv 22.3 13.4 14.1 16.2 bw b b b 13.7 15.4 12.1 18.2 b b b b 16.1 18.0 14.2 14.0 19.9 44.9 b b b b b a Incidence of black scurf on tubers (%)u Index of severity of black scurf on tubers (%)t Yield cwt/A Totalr Marketable (US1)s 75.0 ab 25.0 c 48.8 bc 30.0 c 37.5 bc 33.8 c 18.8 c 26.3 c 17.5 c 32.5 c 16.3 c 42.5 bc 48.4 a 8.4 c 20.0 bc 11.3 c 16.9 c 25.3 bc 7.8 c 11.9 c 5.9 c 14.1 c 5.0 c 24.7 bc 273.9 ab 291.7 ab 299.7 ab 286.0 ab 339.6 a 301.0 ab 283.8 a 304.5 a 306.9 a 294.3 a 348.4 a 310.2 a 312.2 ab 323.8 a 292.6 ab 337.1 a 302.4 ab 324.7 a 292.2 ab 294.8 ab 313.0 a 333.1 a 302.5 a 303.9 a 33.8 c 96.3 a 15.3 c 42.2 ab 309.1 ab 245.5 b 316.4 a 278.6 a 14 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, day of planting to full emergence 23 days after planting. x RAUCPC (max = 100), relative area under the canopy development curve, day of planting to key reference point, 43 days after planting. w Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). v Percentage of stems with greater than 10% girdling caused by R. solani, average of 5 plants taken 43 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. 72 Funding: MPIC / Industry Potato Seed Piece and Variety Response to Variable Rates of Gibberellic Acid 2003-2004 Chris Long and Dr. Willie Kirk Departments of Crop & Soil Sciences and Plant Pathology, Michigan State University, East Lansing, MI. Introduction The Michigan potato industry is currently growing chip processing varieties that have a small set of generally large (over 3.25”) round potatoes. This can cause a problem for seed production. The resulting seed pieces of these varieties are generally oversize and the eye distribution is poor in the cut seed, thus resulting in poor quality seed and the need for higher plant populations. Commercial producers suffer equally from the small set of oversize tubers which results in reduced yield, the need for excess amounts of seed and increased internal tuber defects. The potato industry needs a way to increase tuber set and effectively decrease the size profile of these varieties. In 2003 and 2004 an experiment was conducted on two Frito-Lay, Inc. varieties, FL1879 and FL1833; in 2004 a Michigan State University (MSU) developed clone, Michigan Purple was added. Our goal was to investigate the possibility of increasing tuber set by hormonally influencing the tuber eyes’ ability to produce an increased number of stems. It has been documented that stem number directly influences tuber set (Toosey 1958). Wilkins (1958) indicates that gibberellic acid (GA) is implicated in increasing the number of stems emerging from each tuber eye. Gibberellic acid, although believed to increase the number of stems, ultimately influences tuber size and yield (Smeltzer and MacKay 1963). The objectives of this study are to: (1) establish the effectiveness of GA in inducing greater stem numbers arising from a given potato seed piece and (2) establish whether the increase in stem numbers per plant will increase tuber set and decrease tuber size of three commercially available varieties. Procedure In 2003 and 2004 two varieties, FL1879 and FL1833, were evaluated for their response to three levels of GA. In 2003, seed was obtained and cut into approximately two ounce seed pieces on May 17, 2003. The cut seed was immediately treated with 0, 4, 8, or 12 ppm Pro Gibb 4%, a trademark product of VALENT U.S.A. Corporation. Each treatment required 55 lbs of seed to plant the 3 replication randomized block design. For every 55 lbs of seed, 135 ml of distilled water was used as a carrier for the GA. The control had 135 ml of distilled water applied. The 4 ppm treatment had 0.447 ml of 4% ProGibb added to the water. The 8 ppm treatment had 0.893 ml of ProGibb added and the 12 ppm treatment had 1.34 ml of ProGibb added to the 135 ml of distilled water before it was poured onto the seed. The 55 lbs of cut seed was placed into a light industrial cement 73 mixer and the treatment solution was added. Once the seed pieces appeared uniformly wet an arbitrary amount of bark flour was added to absorb any free water. The seed was placed into plastic ventilated trays and allowed to dry. The plot was planted two days after the seed treatment was applied at the Michigan State University, Montcalm Research Farm, Entrican, Michigan on May 19, 2003. On June 26, 2003 stand counts and the stem numbers per plant were also recorded. Harvest was conducted on September 29, 2003 and total tuber yield, US#1 yield, and total tuber number for four size categories were recorded (< 1 7/8”, Pick-outs, >3 1/4” and 1 7/8” to 3 1/4”), specific gravity, and hollow heart were recorded for each replication. The procedures were very similar for the 2004 season with exception to the application rates for GA. The change in application rates will be explained in the discussion section of this article. In 2004, the application rates were 0, 1, 2 and 4 mg of active ingredient per 100 lbs. (mg a.i./cwt) of cut potato seed. Seed treatments were applied on May 7, 2004 and planting was conducted on May 17, 2004. Stand and stem counts were taken June 24, 2004. The 2004 plot was harvested on October 1, 2004. Due to poor plant stand the FL1833, 4 mg a.i. treatment was lost and no data is presented. Results In 2003 the 8 and 12 ppm treatments for both FL1879 and FL1833 significantly increased stem number (Table 1). Figure 1 depicts the effect of the GA treatments on the cut seed pieces of FL1833. As the concentration of GA increased in the FL1833 variety the US#1 yield decreased. The number of tubers under 1 7/8” increased and the number of oversize tubers decreased (>3 1/4”). The number of “A” size tubers, as well as, the total tuber count per treatment increased as GA level increased (Table 1). For the FL1879 variety, these same trends were observed up to the 8 ppm level. The 12 ppm treatment for the FL1879 variety responded more like its corresponding 4 ppm treatment (Table 1). The line along with GA treatment caused an increase of “B” size tubers. In 2004, both FL1833 and FL1879 exhibited a statistically significant increase in “B” size tubers as GA level increased (Table 1). The variety Michigan Purple displayed a 3 fold increase in the number of “B” size tubers as the GA level was increased from 0 mg a.i. to 4 mg a.i.. Figures 2 and 3 depict the effect of the GA treatments on the cut seed pieces of FL1879 and Michigan Purple, respectively. Discussion The weather at planting in 2003 was far more conducive to a successful growing season than in 2004. Rainfall in early May 2004 caused a number of delays in planting at the Montcalm Research Farm. Cut seed was treated two day prior to planting in 2003 and in 2004 there was a ten day period between seed treatment and planting. The 2004 treated seed was moved into and out of a 50 ºF cooler at least three times, which may have negatively affected seed quality prior to planting. 74 In 2003 the seed treatment rates were measured in ppm as was thought to be the industry standard for GA application. But as the industry was surveyed their GA treatment practices were found to be different, which resulted in an inconsistent seed piece response among growers. Growers were not using the same amount of water to apply a treatment to a given amount of cut seed. For example, one grower was applying 400 ml (3.2 mg a.i.) of an 8 ppm solution to one cwt. of cut seed and another grower was applying 88 ml (0.7 mg a.i.) of the same 8 ppm solution to the same amount of cut seed. As is evident here, the amount of active ingredient applied to the cut seed is influenced by the volume of the treatment solution. This appears to be a problem in identifying consistent results between growers who are treating seed with GA. In 2004 each treatment of GA was measured in mg of active ingredient per 100 pounds of cut seed (mg a.i./ cwt) which was applied by producing a 8 ppm solution and varying the volume of this solution that was applied per cwt. of cut seed. For example, to obtain 1 mg of a.i. per cwt, 125 ml of an 8 ppm GA solution was applied per 100 pounds of cut seed. For 2 mg of GA, 250 ml of the 8 ppm solution would be applied and for 4 mg, 500 ml would be applied. This appears to be a better standard when referring to amount of GA applied to cut seed. In 2005 we are hoping to repeat the study and show the results of this approach to GA application. The spring 2004 weather made it hard to draw many conclusions from this data set. Strictly looking at the results from the 2003 data, it is apparent that the GA treatments do decrease US#1 yield and oversize tuber production. An 8 ppm GA application (approximately 260 ml of solution per cwt cut seed) was the optimal treatment to increase the number of stems per hill, increase the number of “A” and “B” size tubers, while not effecting the specific gravity or number of “pick-out” tubers. Due to the poor growing conditions and seed quality going into the 2004 season, the data that resulted was not very conclusive. This study will be repeated using the mg a.i. treatment system in 2005 with the varieties FL1833, FL1879 and FL1922. Literature Cited Smeltzer, G. G. and D. C. MacKay. 1963. The influence of gibberellic acid seed treatment and seed spacing on yield and tuber size of Potatoes. Am. Potato J. 40:377- 380. Toosey, R. D. 1958. Effect of number of sprouts per set on yield and grading of main- crop potatoes. Nature 182:269-270. Wilkins, W. F. 1958. The effect of gibberellins on production of the Russet Burbank potato. Am. Potato. J. 39:729 (abs.). 75 Table 1. Gibberellic Acid Plot Averages for 2003 and 2004 Field Data GA* Level US# 1 Yield in CWT/A Total Yield in CWT/A 0 4 8 12 0 4 8 12 0 1 2 0 1 2 4 0 1 2 4 324 283 270 268 382 343 311 332 0.001 0.015 0.918 308 244 274 230 335 220 225 293 229 249 276 0.812 0.799 0.36 345 308 291 295 393 367 345 353 0.012 0.082 0.998 316 260 301 239 357 251 258 317 259 274 321 0.684 0.912 0.345 Line FL1833 FL1833 FL1833 FL1833 FL1879 FL1879 FL1879 FL1879 Line** level** Line x level** FL1833 FL1833 FL1833 FL1879 FL1879 FL1879 FL1879 MI Purple MI Purple MI Purple MI Purple Line** level** Line x level** 2003 Tuber Count Total Tuber > 3 1/4" 1 7/8" - 3 1/4" Number <1 7/8" P.O. 13 23 27 33 12 32 45 26 0.014 <0.001 0.001 2004 13 22 36 10 31 34 46 13 25 21 39 0.242 0.015 0.648 5 6 3 5 1 2 4 2 0.003 0.729 0.072 0 2 1 2 0 3 1 6 8 3 7 0.002 0.69 0.168 21 8 6 5 17 7 2 5 0.148 <0.001 0.599 12 6 3 2 1 0 1 8 4 6 2 0.025 0.107 0.367 82 114 130 128 127 163 165 169 <0.001 <0.001 0.789 104 118 127 93 159 118 136 114 98 101 135 0.426 0.537 0.519 121 152 165 171 158 204 216 202 <0.001 <0.001 0.551 128 149 167 106 192 154 183 141 133 131 183 0.554 0.303 0.472 Specific Gravity 1.088 1.086 1.087 1.089 1.082 1.081 1.081 1.083 0.001 0.58 0.956 1.091 1.092 1.094 1.087 1.088 1.088 1.088 1.078 1.076 1.075 1.077 0.001 0.989 0.434 Internal*** Tuber Defects Average # Stems/Hill HH 13 3 0 13 23 3 7 13 1.7 1.8 2.3 2.3 3.5 4.4 4.6 4.6 <0.001 0.004 0.412 1.7 1.6 1.7 2.5 2.9 3.3 4.4 2.5 2.5 2.2 2.55 0.002 0.723 0.058 0.332 0.05 0.782 15 20 3 15 17 0 5 0 0 10 0 0.396 0.645 0.788 * GA level in 2003 was recorded in ppm and in 2004 was recorded as mg of active ingredient per hundred pounds of cut seed. ** P = 0.05 *** 30 tubers per treatment were evaluated for hollow heart (HH). 76 Figure 1. Cut seed of FL1833, 28 days after treatment with GA (2003). 4 ppm 0 ppm Figure 2. Cut seed of FL1879, 28 days after treatment with GA (2004). 8 ppm 1 mg a.i. 2 mg a.i. 0 mg a.i Figure 3. Cut seed of Michigan Purple, 28 days after treatment with GA (2004). 1 mg a.i. 0 mg a.i. 2 mg a.i. 12 ppm 4 mg a.i 4 mg a.i. 77 Funding MPIC and MSU The pathogen Rhizoctonia solani (AG-3) causes stem canker and black scurf of potatoes. Managing Rhizoctonia Diseases of Potato with Optimized Fungicide Applications and Varietal Susceptibility; Results from the Field Experiments. Devan R. Berry, William W. Kirk, Phillip S. Wharton, Robert L. Schafer, and Pavani G. Tumbalam Department of Plant Pathology, Michigan State University, East Lansing, MI 48824 Phone (517) 355-4481, Fax 353-1926 (kirkw@msu.edu) Introduction Rhizoctonia diseases are initiated by seedborne or soilborne inoculum. Seedborne inoculum is carried on seed tubers in the form of sclerotia (black scurf) or as mycelium from the previous season. When contaminated seed is planted the fungus grows from the seed surface to the developing sprout and infection of root primordia, stolon primordia and leaf primordia can occur. The sprouts can be killed at this stage and emergence may be prevented or delayed. Mycelia and sclerotia of R. solani also survive in soil and on plant debris and can cause disease independently of seedborne inoculum. Soilborne inoculum can infect potato tissue at anytime when plant organs develop in the proximity of inoculum, however the plant is most severely impacted when immature sprouts, stolons and roots are infected early in the season. During early potato development in April in MI soil temperature is well within the optimal range (average about 10oC) for infection by R. solani. High temperature tends to minimize the impact of R. solani even when inoculum is abundant. Some potato varieties appear to be more sensitive than others to but there are none which exhibit high levels of resistance, however information on currently grown varieties is not available. Current recommendations for control of this disease are focused on reducing both seedborne and soilborne inoculum. It is known that minimizing the time between planting and emergence can minimize sprout infection. Crop rotation in warm climates to about three years can also reduce inoculum in the soil. As growers in MI are constrained by season length and rotation requirements it is necessary to include the application of fungicides effective against R. solani in a control program. Trials at MSU and elsewhere have indicated that there are several effective fungicides that can be used to manage R. solani, either applied as seed treatments or as in-furrow at-planting applications. These fungicides include fludioxonil- based seed treatments (Maxim products), strobilurin-based products applied in-furrow [azoxystrobin (Quadris, Amistar); pyraclostrobin (Headline), trifloxystrobin (Gem)], and flutolonil-based fungicides [Moncoat MZ (seed treatment); Moncut (in-furrow)]. Although products are available, new standards are being developed for avoidance of resistance in pathogen populations (not necessarily R. solani) to at-risk fungicide classes such as those in group 11 [QoI-fungicides (Quinone outside Inhibitors)] which includes all the strobilurines currently registered for use on potatoes. The broad spectrum of efficacy reported in strobilurines may lead to excessive use in the future as other products such as B2 carcinogens are at risk of further limitations in usage, and therefore a management plan for their use need to be developed which is compatible with potato production in MI. Currently there are many fungicide options available for control of Rhizoctonia diseases of potato however, to achieve optimal performance and preserve efficacy, a systematic approach of usage needs to be established. This approach also should address the climatic variability on the epidemiology of R. solani in potatoes to establish the threshold at which the application of fungicide intervention would have no effect. (identified below) applied at different timings during early crop development in combination with and without seed treatments on a chipping cultivar and a table stock cultivar grown in two potentially different soil temperature regimes; and B) evaluate the effect of soil temperature on currently grown varieties at the Plant Pathology Research Farm on a sand/mineral site. Materials and Methods A) The seed treatment and fungicide application timing experiment for the control of symptoms of Rhizoctonia solani was tested at two locations and on three varieties. The potato cultivar ‘Superior’ was planted in a grower’s field near Elmira, MI, while the cultivars ‘FL 1879’ and ‘Russet Norkotah’ were planted at the Michigan State University Muck Soils Research farm near Bath, MI. All three The objectives of this project therefore are to A) to identify the efficacy of some fungicides 78 Funding MPIC and MSU In-furrow Emergence In-furrow Emergence Amistar Moncut Headline Amistar Moncut Headline 14 day post- emergence Amistar Moncut Headline cultivars were tested for the control of Rhizoctonia disease symptoms under identical chemical regimes. Within each regime three chemicals, Amistar (a.i. azoxystrobin), Moncut (a.i. flutolonil), Headline (a.i. pyraclostrobin), were examined for efficacy at three application times, at-planting in-furrow, at emergence, and 14 days after emergence. Also, the efficacy of the addition of a seed treatment, Maxim (a.i., fludioxonil), in combination with the fungicides was examined at each application timing (Table 1). Table 1: Experimental layout for seed treatment and timing of application of fungicides in-furrow at- planting, emergence and post-emergence Seed treatment Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes were planted near Elmira, MI in sandy loam soil on 2 June, into four- row by 20 ft plots (approximately 13-in. between plants give a target population of 72 at 34-in. row spacing) replicated four times in a randomized complete block design. Cut ‘FL1879’ seed and whole ‘Russet Norkotah’ seed was also treated with the seed treatment one day prior to planting. Seed pieces were planted in Houghton muck soil at the Michigan State University Muck Soils Research Farm, Bath, MI on 23 June, into four- row by 20 ft plots (approximately 13-in. between plants give a target population of 72 at 34-in. row spacing) replicated four times in a randomized complete block design. The seed treatment was applied, in a water suspension of at a rate of 0.8 fl. oz/cwt in 0.8 fl. oz/cwt of water for a total final solution of 0.16 fl. oz/cwt, onto the entire seed surface. In-furrow applications were made over the seed at-planting, applied with a single nozzle R&D spray boom delivering 5 gal/A (80 psi) and using one XR11003VS nozzle per row. ‘Superior’ seed was cut and treated with the seed treatment one day prior to planting. Seed pieces 14 day post- emergence Amistar Moncut Headline Seed treatment No No No No No No No No No No Amistar Moncut Headline Amistar Moncut Headline At the Elmira site, pesticides were applied by the grower cooperator. Weeds were controlled with 1 lb/A of Lorox and 0.5 lb/A Sencor at hilling, and Eptam was applied at a rate of 3.5 pt/A (broadcast rate) 6 times throughout the growing season. Insects were controlled with Platinum applied at a rate of 0.25 pt/A at-planting, and Asana was used once at 8 oz/A. Seven applications of Bravo WS 6SC, three applications of Bravo WS 6SC with Endura 6WDG, and one application of Bravo WS 6SC with Copper Oxychloride were used as protectants against other fungal pathogens on a seven day spray schedule. Bravo WS 6SC was used at a rate of 1.5pt/A, Endura 6WDG was used at a rate of 0.16 lb/A, and Copper Oxychloride was used at a rate of 1 lb/A. Fertilizer was drilled into plots before planting, formulated according to results of soil tests at the Bath, MI location. Bravo WS 6SC was applied at 1.5 pt/A on a ten day interval, total of six applications, starting two weeks after the last application of experiment treatments. 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 with Dual 8E at 2 pt/A 15 DAP (days after planting), Basagran at 2 pt/A 25 and 45 DAP and Poast at 1.5 pt/A 63 DAP. Insects were controlled with Admire 2F at 1.25 pt/A at-planting, Sevin 80S at 1.25 lb/A 36 and 60 DAP, Thiodan 3 EC at 2.33 pt/A 70 DAP and Pounce 3.2EC at 8 oz/A 53 DAP. planting. The rate of emergence was estimated as the area under the plant emergence curve (max=100) from the day of planting until 29 DAP for ‘Superior and 20 DAP for ‘FL1879’ and ‘Russet Norkotah’. Emergence was rated as the number of plants breaking the soil surface or fully emerged after 79 Funding MPIC and MSU Tuber, stem, and stolon numbers, and percentages of stems and stolons with greater than 5% girdling caused by Rhizoctonia solani were measured via a destructive mid-season harvest (4 plants per ‘Superior’ replication, and 2 plants per replication for ‘FL1879’ and ‘Russet Norkotah’) at 50 DAP for all three varieties. Vines were killed with Reglone 2EC (1 pt/A on 1, and 23 Sep at Elmira and Bath, respectively). Plots (20-ft row) were harvested on 13 Oct and individual treatments were weighed and graded. Samples of 20 tubers per plot were washed and assessed for black scurf (R.. solani) incidence (%) and severity 13 days after harvest on 26 Oct. Severity of black scurf was measured as an index calculated by counting the number of tubers (n = 20) falling in class 0 = 0%; 1 = 1 - 5%; 2 = 6 -10%; 3 = 11 – 15%; 4 = > 15% 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. B) The variety experiment was located at the Plant Pathology farm in East Lansing, MI and tested nine potato cultivars (Atlantic, FL1833, FL1867, FL1879, Jacqueline Lee, Michigan Purple, Pike, Russet Norkotah, and Snowden). The nine varieties were planted at three times, which were done once the soil temperature at 4-in. reached a daily average of 8, 14 and 20oC. The soil temperatures were monitored at each planting time with a Cole-Parmer 12 channel scanning thermometer. Each planting took place once the threshold (8, 14, 20oC) was surpassed as a one day average. Timing 1 was planted 19 April, timing 2 on 17 May, and timing 3 on 28 June. Tubers were hand planted into pre-hilled sandy soil in four rows by 10 ft. treatments in a randomized complete block design. Plants were spaced approximately 12-in. apart, with each row having nine plants (36 plants total per replication). Vines were killed with Reglone 2EC (1 pt/A on 17 Sep). All tubers from four plants were harvested from all timings on 4 Oct. Tubers were washed and assessed for black scurf (R. solani) incidence (%) and severity 24 days after harvest on 28 Oct, as described above. Results and Conclusions The effect of seed treatment, fungicide application, and timing of the applications in-furrow at- planting, emergence or post-emergence on potato growth and development and yield (See Table 2 A- C) Fungicide treatments on ‘Superior’ with no seed treatment • The rate of emergence (RAUEPC) for applications of Headline at emergence (8) and 14 days post- emergence (9) were significantly higher than either the application of Amistar at 14 days post- emergence (3) or Headline applied at-planting (7), but there was not a significant difference between any treatment and the untreated control (10). Treatments with RAUEPC values between 0.39 - 0.44 and 0.41 - 0.45 were not significantly different. • The number of tubers was significantly higher for treatments of Moncut at all three application times (4, 5, 6), and Headline applied at emergence (8) compared to the untreated control (10). There were no other significant differences among treatments with the exception between treatment of Amistar at-planting (1) and Moncut at emergence (5). Treatments with the number of tubers between 12.0 - 16.9, 14.1 - 19.0 and 16.9 - 20.5 were not significantly different. • The number of stems for Moncut applied at emergence (5) and 14 days post-emergence (6) was significantly higher than the untreated control (10), but there was no difference among treatments. Treatments with the number of stems between 2.3 - 3.3 and 2.9 - 3.8 were not significantly different. • The stolon number was significantly higher for Amistar applied at emergence (2) and Moncut applied at emergence (5) or 14 days post-emergence (6) compared to the untreated control (10), but there was not a significant difference among them. Also, applications of Moncut at emergence (5) and 14 days post-emergence (6) were significantly higher than applications of Amistar 14 days post-emergence (3), and at-planting applications of Moncut (4) and Headline (7). Treatments with the number of stolons between 10.9 - 14.1, 11.6 - 14.6, 12.4 - 16.0 and 13.4 - 16.9 were not significantly different. • Marketable yield of Amistar applied at emergence (2) was significantly lower than either in-furrow at-planting applications of Amistar (1) or Headline (7), and Moncut applied 14 days post-emergence (6). However, no treatment was significantly different from the untreated control (10). Treatments 80 Funding MPIC and MSU with a marketable yield between 381.3 – 424.4 and 390.0 – 441.6 cwt/A were not significantly different. Fungicide treatments on ‘Superior’ with seed treatment • Headline applied at emergence (8), 14 days post-emergence (9) and Amistar applied 14 days post- emergence (3) had significantly higher rates of emergence (RAUEPC) compared to Moncut applied in-furrow at-planting (4), but there was not a significant difference between any treatment and the untreated control (10). Treatments with a RAUEPC value between 0.41 - 0.46, 0.42 - 0.47 and 0.44 - 0.49 were not significantly different. • The number of tubers was significantly higher for Headline applied at emergence (8) and 14 days post-emergence (9) compared to Moncut applied 14 days post-emergence (6) but no treatment significantly differed from the untreated control (10). Treatments with the number of tubers between 19.4 - 23.9, and 19.6 - 24.8 were not significantly different. • Headline applied at emergence (8) had a significantly higher number of stems than the application of Amistar at emergence (2), but no treatment differed significantly from the untreated control (10). Treatments with the number of stems between 3.4 – 4.4 and 3.8 – 4.8 were not significantly different. • The number of stolons was significantly higher for Headline applied at emergence (8) and 14 days post-emergence (9) compared to the untreated control (10). In addition, the number of stolons was significantly higher for Headline applied at emergence (8) compared to Amistar at emergence (2) and Moncut applied 14 days post-emergence. Treatments with the number of stolons between 16.1 – 20.8, 16.9 – 21.9, and 18.4 – 23.3 were not significantly different. • Marketable yield was not significantly different among treatments (316.5 – 372.9 cwt/A). Fungicide treatments on ‘FL1879’ with no seed treatment • There was no significant difference among treatments for the rate of emergence (RAUEPC). Treatments with RAUEPC values between 0.11 - 0.14 were not significantly different. • The number of tubers among treatments was not significantly different (23.5 – 43.6). • Moncut applied in-furrow at-planting (4) had a significantly higher number of stems compared to either the untreated control (10) or Amistar applied at emergence (2). Treatments with the number of stems between 3.3 – 5.4 and 3.8 – 6.3 were not significantly different. • Moncut applied in-furrow at-planting (4) had a significantly higher number of stolons compared to the untreated control (10). Treatments with the number of stolons between 34.1 – 49.8 and 40.0 – 59.9 were not significantly different. • Amistar applied at emergence (2) had a significantly higher marketable yield than Moncut applied 14 days post-emergence (6), but no treatment was significantly different yield from the untreated control (10). Treatments with a marketable yield between 297.1 – 429.0 and 323.6 – 506.6 were not significantly different. Fungicide treatments on ‘FL1879’ with seed treatment • The untreated control (10) had a significantly lower rate of emergence (RAUEPC) than Amistar applied in-furrow at-planting (1), Moncut applied either in-furrow at-planting (4) or 14 days post- emergence (6) and Headline applied at emergence (8). Treatments with a RAUEPC value between 0.12 - 0.16, 0.13 – 0.17 and 0.14 and 0.18 were not significantly different. • The number of tubers among treatments was not significantly different (31.5 – 45.8). • Both Amistar applied in-furrow at-planting (1) and at emergence (2) had significantly higher numbers of stems compared to either Amistar or Headline applied 14 days post-emergence (3, 9). However, no treatment was significantly different from the untreated control (10). Treatments with the number of stems between 4.5 – 7.3 and 5.0 – 7.8 were not significantly different. • The number of stolons among treatments was not significantly different (38.8 – 64.0). • Moncut applied at emergence (5) had a significantly higher marketable yield than Amistar applied in- furrow at-planting (1), but no treatment was significantly different yield from the untreated control (10). Treatments with a marketable yield between 321.1 – 409.5 and 334.9 – 421.4 were not significantly different. Fungicide treatments on ‘Russet Norkotah’ with no seed treatment 81 Funding MPIC and MSU • Headline applied in-furrow at-planting (7) had a significantly higher rate of emergence (RAUEPC) than all other treatments except Headline applied at emergence (8). Treatments with a RAUEPC value between 0.19 - 0.21 and 0.21 and 0.22 were not significantly different. • The number of tubers among treatments was not significantly different (24.8 – 33.9). • The number of stems among treatments was not significantly different (3.8 – 5.1). • Only Headline applied at emergence (8) had a significantly lower number of stolons compared to the untreated control (10). Treatments with the number of stolons between 10.0 – 15.5 and 10.3 – 16.3 were not significantly different. • Amistar applied 14 days post-emergence (3) and Moncut applied in-furrow at-planting (4) both had significantly higher marketable yields than Headline applied at emergence (8), but there was no treatment was significantly different from the untreated control (10). Treatments with a marketable yield between 155.6 – 250.8 and 219.6 – 261.5 were not significantly different. Fungicide treatments on ‘Russet Norkotah’ with seed treatment • Amistar applied at emergence (2) and 14 days post-emergence (3) and Moncut at emergence (5) had significantly higher rates of emergence (RAUEPC) compared to Moncut applied 14 days after emergence (6). In addition, both Amistar applied 14 days post-emergence (3) and Moncut applied at emergence (5) had a significantly higher rate of emergence (RAUEPC) than Headline applied in- furrow at-planting (7). However, there was no treatment that had a significant difference from the untreated control (10). Treatments with a RAUEPC value between 0.185 - 0.204, 0.188 - 0.208, and 0.195 – 0.212 were not significantly different. • The number of tubers among treatments was not significantly different (26.3 – 36.3). • The number of stems among treatments was not significantly different (4.3 – 6.0). • The number of stolons among treatments was not significantly different (10.1 – 17.1). • Marketable yield was not significantly different among treatments (177.9 – 250.4 cwt/A). The effect of seed treatment, fungicide application, and timing of the applications in-furrow at- planting, emergence or post-emergence on disease symptoms caused by Rhizoctonia solani growth and development (See Table 3 A – C) Fungicide treatments on ‘Superior’ with no seed treatment • Headline applied in-furrow at-planting (7) and 14 days post-emergence (9) had significantly lower percentages of diseased stems compared to Moncut applied in-furrow at-planting (4), but no treatment was significantly different from the untreated control (10). Treatments with the percentage of diseased stems between 13.5 – 37.5 and 16.7 – 41.7 were not significantly different. • Moncut applied in-furrow at-planting (4) had a significantly higher percentage of diseased stolons than Moncut applied 14 days post-emergence (6) or Headline applied either in-furrow at-planting (7) or at emergence (8), but no treatment was significantly different from the untreated control (10). Treatments with the percentage of diseased stolons between 1.0 – 15.7 and 4.0 -23.2 were not significantly different. • Headline applied at emergence (8) had a significantly higher incidence of Rhizoctonia sclerotia on mature tubers compared to Amistar applied 14 days post-emergence (3) and both Moncut and Headline applied in-furrow at-planting (4, 7). There was no significant difference between any treatment and the untreated control (10). Treatments with an incidence value between 0.0 – 23.8 and 7.5 – 35.0 were not significantly different. • Headline applied at emergence (8) had a significantly higher severity of Rhizoctonia sclerotia on mature tubers compared to Amistar applied 14 days post-emergence (3) and both Moncut and Headline applied in-furrow at-planting (4, 7). There was no significant difference between any treatment and the untreated control (10). Treatments with a severity value between 0.0 – 12.8 and 3.4 – 17.2 were not significantly different. Fungicide treatments on ‘Superior’ with seed treatment • The percentage of diseased stems was not significantly different among treatments (6.4 – 16.9). 82 Funding MPIC and MSU • Moncut applied 14 days post-emergence (6) had a significantly higher percentage of diseased stolons compared to the untreated control (10), all application timings of Amistar (1, 2, and 3), and both Moncut and Headline applied in-furrow at-planting (4, 7). Treatments with a percentage of diseased stems between 1.5 – 4.5 and 3.8 – 8.5 were not significantly different. • The incidence of Rhizoctonia sclerotia on mature tubers was not significantly different among treatments (0.0 – 8.8). treatments (0.0 – 5.6). • The severity of Rhizoctonia sclerotia on mature tubers was not significantly different among Fungicide treatments on ‘FL1879’ with no seed treatment • Headline applied in-furrow at-planting (7) had a significantly lower percentage of diseased stems than Headline applied at emergence (8) and Moncut applied in-furrow at-planting (4), but no treatment was significantly different from the untreated control (10). Treatments with a percentage of diseased stems between 14.8 – 42.9, 19.8 – 46.7 and 25.6 – 53.3 were not significantly different. • Amistar applied in-furrow at-planting (1) had a significantly lower percentage of diseased stolons compared to Amistar applied at emergence (2) and both Headline applied at emergence (8) and 14 days post-emergence (9), but no treatment was significantly different from the untreated control (10). Treatments with a percentage of diseased stolons between 38.8 – 70.0, 43.8 – 75.0 and 53.8 – 81.3 were not significantly different. • Headline applied at emergence (8) had a significantly higher incidence of Rhizoctonia sclerotia on mature potatoes compared to Amistar applied in-furrow at-planting (1) and Moncut applied 14 days post-emergence (6), but no treatment that was significantly different from the untreated control (10). Treatments with an incidence value between 38.8 – 70.0, 43.8 – 75.0, and 53.8 – 81.3 were not significantly different. • Headline applied at emergence (8) had a significantly higher severity of Rhizoctonia sclerotia on mature potatoes compared to Amistar applied in-furrow at-planting (1) and Moncut applied 14 days post-emergence (6), but no treatment was significantly different from the untreated control (10). Treatments with a severity value between 18.4 – 39.4, and 24.7 – 44.7 were not significantly different. Fungicide treatments on ‘FL1879’ with seed treatment • Headline applied in-furrow at-planting (7) had a significantly higher percentage of diseased stems compared to Amistar applied at emergence (2) and Headline applied 14 days post-emergence (9), but no treatment was significantly different from the untreated control (10). Treatments with a percentage of diseased stems between 11.9 – 43.1 and 23.2 – 54.1 were not significantly different. • Amistar applied at emergence (2) had a significantly lower percentage of diseased stolons compared to the untreated control (10). Treatments with a percentage of diseased stolons between 10.2 - 33.4 and 23.1 – 40.6 were not significantly different. • The incidence of Rhizoctonia sclerotia on mature tubers was not significantly different among treatments (47.5 – 77.5). treatments (21.9 – 41.9). • The severity of Rhizoctonia sclerotia on mature tubers was not significantly different among Fungicide treatments on ‘Russet Norkotah’ with no seed treatment • Headline applied at emergence (8) had a significantly lower percentage of diseased stems compared to either Headline applied in-furrow at-planting (7) or the untreated control (10). Treatments with a percentage of diseased stems between 42.1 – 72.9 and 58.1 – 82.3 were not significantly different. • The percentage of diseased stolons was not significantly different among treatments (28.6 – 54.9). • Amistar applied at emergence (2) had significantly lower incidence of Rhizoctonia sclerotia on mature tubers compared to Headline applied in-furrow at-planting (7), and either Amistar or Moncut applied 14 days post-emergence (3, 6). However, no treatment was significantly different from the untreated control (10). Treatments with an incidence value between 30.0 – 56.3 and 42.5 – 63.8 were not significant. 83 Funding MPIC and MSU • Amistar applied at emergence (2) had significantly lower severity of Rhizoctonia sclerotia on mature tubers compared to the untreated control (10), Moncut either applied in-furrow at-planting (4) or 14 days post-emergence (6), Headline applied in-furrow at-planting (7) and Amistar applied 14 days post-emergence (3). Treatments with a severity value between 10.0 – 23.8 and 17.8 – 31.6 were not significant. Fungicide treatments on ‘Russet Norkotah’ with seed treatment • Amistar applied at emergence (2) and Headline applied in-furrow at-planting (7) had significantly lower percentages of diseased stems compared to Moncut applied in-furrow at-planting (4), but no treatment was significantly different from the untreated control (10). Treatments with a percentage of diseased stems between 45.2 – 75.7 and 51.9 – 80.8 were not significantly different. • Headline applied in-furrow at-planting (7) had significantly lower percentages of diseased stolons compared to Amistar applied 14 days post-emergence (3), Moncut applied in-furrow at-planting (4), and Headline applied at emergence (8), but no treatment was significantly different from the untreated control (10). Treatments with a percentage of diseased stolons between 9.9 – 33.9 and 16.6 – 41.8 were not significantly different. • The incidence of Rhizoctonia sclerotia on mature tubers was not significantly different among • The severity of Rhizoctonia sclerotia on mature tubers was not significantly different among treatments (37.5 – 56.3). treatments (15.6 – 26.6). The effect of seed treatment on potato growth and development and yield (See Table 4) and on disease symptoms caused by Rhizoctonia solani growth and development (See Table 5) ‘Superior’ • Treatments with the seed treatment Maxim 4FS had significant increases in the rate of emergence (RAUEPC), tuber, stem and stolon number, but had a significant decrease in marketable yield when compared to treatments without the seed treatment. • Treatments with the seed treatment had a significantly lower percentage of stems and stolons with greater than 5% girdling, compared with treatments without the seed treatment. In addition, treatments with the seed treatment also significantly reduced both the incidence and severity of sclerotia formed by Rhizoctonia solani on mature tubers, when compared to treatments without the seed treatment. ‘FL1879’ • Treatments with the seed treatment Maxim 4FS had significant increases in the rate of emergence (RAUEPC), and the number of tubers, when compared to treatments without the seed treatment. However, there were not significant differences for the number of tubers, numbers of stolons or marketable yield. • The treatments with the seed treatment significantly reduced the percentage of stems with greater than 5% girdling, when compared to treatments without the seed treatment. There was no significant difference between treatments with and without the seed treatment for the percentage of stolons with greater than 5% girdling, or the incidence and severity of sclerotia formed by Rhizoctonia solani on mature tubers. ‘Russet Norkotah’ • Treatments with the seed treatment Maxim 4FS had a significant increase on the number of tubers, compared with treatments without the seed treatment. There were not significant differences between treatments with and without the seed treatment for the rate of emergence (RAUEPC), the number of tubers, numbers of stolons or marketable yield. • Treatments with the seed treatment significantly reduced the percent of solons with greater than 5% girdling, compared to treatments without the seed treatment. There was no significant difference between treatments with and without the seed treatment for the percentage of stems with greater than 5% girdling, or the incidence and severity of sclerotia formed by Rhizoctonia solani on mature tubers. 84 Funding MPIC and MSU The effect of seed treatment and the timing of application of fungicides in-furrow at-planting (IF), emergence (Em), or 14 days post-emergence (PE) on potato growth and development and yield (see Table 6), and on disease symptoms caused by Rhizoctonia solani (see Table 7) ‘Superior’ with no seed treatment • There was no significant difference among application times for the rate of emergence (RAUEPC). Application times with RAUEPC values between 0.40 – 0.43 were not significantly different. Also, there was no significant difference among application times for the number of tubers (15.6 – 18.7) and the number of stems (3.1 – 3.3). Treatments that were applied at emergence (Em) had significantly higher number of stolons compared to treatments applied in-furrow at-planting (IF). Application times with the number of stolons between 12.3 – 13.8 and 13.8 – 14.9 were not significantly different. Treatments applied in-furrow at-planting (IF) had significantly higher marketable yield when compared to treatments applied at emergence (Em). Application times with a marketable yield between 391.0 – 417.8 and 417.8 – 432.1 were not significantly different. • There was no significant difference among application times for the percentage of diseased stems (18.1 – 27.5), percentage of diseased stolons (7.2 – 13.3), or the severity of R. solani on mature tubers (1.7 – 10.4). Treatments applied in-furrow at-planting (IF) had a significantly lower incidence of R. solani on mature tubers compared to treatments applied at emergence (Em). ‘Superior’ with seed treatment • The rate of emergence (RAUEPC) for treatments applied in-furrow at-planting (IF, 0.42) was significantly lower than treatments applied either at emergence (Em, 0.46) or 14 days post-emergence (PE, 0.45). Application times were not significantly different for the number of tubers (21.8 – 23.0), stems (4.0 – 4.2), stolons (19.5 – 19.6) or marketable yield (335.2 – 358.4 cwt/A). • There was no significant difference among application times for the percentage of diseased stems (8.8 – 13.7), incidence of R. solani on mature tubers (2.5 – 2.9), or the severity of R. solani on mature tubers (0.8 – 1.9). Treatments applied in-furrow at-planting (IF) had a significantly lower percentage of diseased stolons compared to treatments applied 14 days post-emergence (PE). Application times with a percentage of diseased stolons between 2.7 – 3.7 and 3.7 – 5.5 were not significantly different. ‘FL1879’ with no seed treatment • Application times were not significantly different for the rate of emergence (RAUEPC) (0.12 – 0.13), the number of tubers (35.0 – 37.5), stems (4.3 – 5.3), stolons (42.4 – 49.9), and marketable yield (369.4 – 392.5 cwt/A). • There was no significant difference among application times for either the percentage of diseased stems (37.4 – 53.3) or the percentage of diseased stolons (29.6 – 34.4). Treatments applied in-furrow at-planting (IF) had both a significantly lower incidence and severity of sclerotia formed by Rhizoctonia solani compared to treatments applied at emergence (Em). Application times with an incidence value between 51.7 – 59.2 and 59.2 – 74.6, or severity values between 24.3 – 30.5 and 30.5 – 40.7 were not significantly different. ‘FL1879’ with seed treatment • Application times were not significantly different for the rate of emergence (RAUEPC) (0.15 – 0.16), the number of tubers (36.2 – 42.5), stems (5.4 – 6.5), stolons (46.9 – 60.5), and marketable yield (359.1 – 366.1 cwt/A). • Application times were not significantly different for the percentage of diseased stems (21.5 – 41.0), percentage of diseased stolons (21.1 – 27.5), incidence of sclerotia formed by Rhizoctonia solani (56.3 – 65.4) and severity of sclerotia (27.1 – 35.3). ‘Russet Norkotah’ with no seed treatment • Application times were not significantly different for the rate of emergence (RAUEPC) (0.19 – 0.20), the number of tubers (27.7 – 29.7), stems (3.8 – 4.6), stolons (11.4 – 12.8), and marketable yield (208.0 – 249.7 cwt/A). • Application times were not significantly different for the percentage of diseased stems (57.2 – 75.0), percentage of diseased stolons (35.3 – 39.2), and incidence of sclerotia formed by Rhizoctonia solani (42.9 – 57.1). Treatments applied at emergence (Em) had a significantly lower severity of sclerotia 85 Funding MPIC and MSU formed by Rhizoctonia solani on mature tubers compared to treatments applied 14 days post- emergence (PE). Application times with a severity value between 17.7 – 23.6 and 23.6 – 26.7 were not significantly different. ‘Russet Norkotah’ with seed treatment • Application times were not significantly different for the rate of emergence (RAUEPC) (0.19 – 0.20), the number of tubers (30.9 – 32.5), stems (4.6 – 5.3), stolons (13.4 – 14.4), and marketable yield (192.9 – 228.7 cwt/A). • Application times were not significantly different for the percentage of diseased stems (60.5 – 64.2), percentage of diseased stolons (25.6 – 32.3), incidence of sclerotia formed by Rhizoctonia solani (44.2 – 50.0) and severity of sclerotia (19.2 – 22.0). The effect of planting time for nine varieties of potato, based upon soil temperature (8, 14, or 20oC), on incidence and severity of sclerotia formed by Rhizoctonia solani on mature tubers; East Lansing, MI; 2004 (See Table 8) Timing 1 (8o C) • There was no difference among cultivars for the incidence of sclerotia formed by R. solani on mature tubers (61.65 – 100). ‘FL1833’ had a significantly higher value of severity of sclerotia formed by R. solani on mature tubers compared to cultivars ‘Pike’, ‘FL1879,’ and ‘Snowden. Cultivars with a severity value between 10.92 - 22.08 and 14.61 – 29.48 were not significantly different. Timing 2 (14o C) • ‘Jacqueline Lee’ had a significantly higher incidence of sclerotia formed by R. solani on mature tubers compared to all cultivars except ‘Snowden’, ‘FL1833’, and ‘FL1879’. Cultivars with an incidence value between 4.23 – 39.28 and 13.27 – 62.83 were not significantly different. ‘Jacqueline Lee’ had a significantly higher severity of sclerotia formed by R. solani on mature tubers compared to all cultivars except ‘Snowden’, ‘FL1833’, and ‘FL1879’. Cultivars with a severity value between 0.42 – 7.19 and 4.35 – 11.54 were not significantly different. Timing 3 (20o C) • Both cultivars ‘MI Purple’ and ‘FL1879’ had a significantly lower incidence of sclerotia formed by R. solani on mature tubers compared to ‘Jacqueline Lee’, ‘Atlantic’, and ‘Snowden’. Cultivars with an incidence value between 0.0 – 15.18, 5.68 – 29.00, 15.18 – 37.02 were not significantly different. • Both cultivars ‘MI Purple’ and ‘FL1879’ had significantly lower incidence of sclerotia formed by R. solani on mature tubers compared to ‘Jacqueline Lee’, and ‘Snowden’. Cultivars with an incidence value between 0.0 – 2.14, 0.36 – 6.75, 0.57 – 7.16 and 2.14 – 8.35 were not significantly different. The effect of planting time based upon soil temperature (8, 14, or 20oC) on incidence and severity of sclerotia formed by Rhizoctonia solani on mature tubers; East Lansing, MI; 2004 (See Table 9) • Planting time 1 (8oC) had a significantly higher incidence of sclerotia formed by R. solani on mature tubers compared to planting times 2 (14oC) and 3 (20oC). • Planting time 1 (8oC) had a significantly higher severity of sclerotia formed by R. solani on mature tubers compared to planting times 2 (14oC) and 3 (20oC). • • 86 Funding MPIC and MSU Table 2a-c: The effect of seed treatment, fungicide application, and the timing of application; in-furrow at-planting (IF), emergence (Em), or 14 days post-emergence (PE) on potato growth and development and yield. Experiments located at A) Elmira, MI, ‘Superior’; B) Bath, MI, ‘FL1879’; C) Bath, MI, ‘Russet Norkotah’; 2004. Seed Treatment Application Rate of Emergence timing z Treatment Application (amount per 1000 ft) Amistar 80WDG 0.25 oz Moncut 70DF 1.18 oz Headline 0.21 fl oz Non-treated None Maxim 4FS v Amistar 0.25 oz Treatment number A 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 z Application timings: In-furrow at-planting (IF); at emergence (Em); 14 days post-emergence (PE) y RAUEPC: Relative area under the emergence progress curve (max = 100), calculated from the day of planting to 38 days after planting x Numbers of tubers, stems, and stolons are the average of 4 plants (per replicate) taken 50 days after planting w Marketable yield: all tubers greater than 2.5” in any plane (US1 grade), 84 days after planting for v Maxim 4FS at Seed treatment at 0.08 fl oz/cwt u Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison) Tuber number x bc abc bc ab a ab bc ab bc c ab ab ab ab ab b ab a a ab 14.1 16.9 14.5 19.0 20.5 17.1 14.3 18.8 15.3 12.0 22.6 20.6 22.9 23.9 19.9 19.4 22.4 24.8 24.8 19.6 (RAUEPC) y ab u 0.41 ab 0.41 b 0.39 ab 0.41 0.43 ab ab 0.44 b 0.39 a 0.45 a 0.44 0.44 ab 0.44 bc abc 0.44 ab 0.47 0.41 c abc 0.46 bc 0.43 bc 0.42 0.49 a 0.46 ab abc 0.45 Stem number x ab ab ab ab a a ab ab ab b ab b ab ab ab ab ab a ab ab 2.9 3.1 2.9 3.3 3.8 3.6 3.0 3.1 2.9 2.3 4.4 3.4 4.0 4.0 3.8 4.1 3.9 4.8 4.4 4.1 Moncut 70 DF 1.18 oz Headline 0.21 fl oz Non-treated IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE Stolon number x 13.4 14.6 12.1 11.6 16.0 16.9 11.8 14.1 12.4 10.9 19.7 16.9 19.3 18.4 18.4 17.4 20.8 23.3 21.9 16.1 abcd abc cd cd ab a cd abcd bcd d abc bc abc abc abc bc abc a ab c Marketable Yield cwt/A w 441.6 a b 381.3 ab 424.4 ab 416.1 392.6 ab a 439.1 a 438.6 ab 399.1 ab 390.0 409.6 ab a 335.6 a 316.5 a 358.9 349.5 a a 338.0 a 344.6 a 360.0 351.1 a a 371.8 372.9 a 87 Funding MPIC and MSU IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE Application Rate of Emergence timing z (RAUEPC) y Tuber number x Stem number x Treatment Application (amount per 1000 ft) Amistar 80WDG 0.25 oz Moncut 70DF 1.18 oz Headline 0.21 fl oz Non-treated Seed Treatment None Maxim 4FS v Amistar 0.25 oz Treatment number B 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 z Application timings: In-furrow at-planting (IF); at emergence (Em); 14 days post-emergence (PE) y RAUEPC: Relative area under the emergence progress curve (max = 100), calculated from the day of planting to 20 days after planting x Numbers of tubers, stems, and stolons are the average of 2 plants taken 50 days after planting w Marketable yield: all tubers greater than 2.5” in any plane (US1 grade), 90 days after planting v Maxim 4FS at Seed treatment at 0.08 fl oz/cwt u Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison) Moncut 70 DF 1.18 oz Headline 0.21 fl oz Non-treated 28.8 32.0 35.8 40.1 42.4 30.9 43.6 33.4 38.4 28.5 40.5 40.1 41.8 41.1 31.5 40.3 45.8 37.0 43.8 41.3 41.9 42.6 40.0 59.0 49.8 40.1 48.9 40.1 47.1 34.1 64.0 52.8 50.1 56.3 38.8 59.3 61.4 49.1 46.8 42.5 0.11 0.11 0.14 0.14 0.13 0.13 0.13 0.12 0.12 0.12 0.17 0.15 0.13 0.17 0.16 0.17 0.15 0.18 0.14 0.12 a a a a a a a a a a ab abc bc ab abc ab abc a abc c 4.4 3.3 3.8 6.3 5.1 4.6 5.3 5.4 4.4 3.3 7.8 7.5 4.5 5.8 5.0 7.3 6.1 5.0 4.5 5.6 ab b ab a ab ab ab ab ab b a a b ab ab ab ab ab b ab a a a a a a a a a a a a a a a a a a a a Stolon number x Marketable Yield cwt/A w ab ab ab a ab ab ab ab ab b a a a a a a a a a a 413.1 506.6 429.0 350.1 330.9 297.1 352.8 340.0 382.1 323.6 321.1 339.0 334.9 393.3 421.4 409.5 363.0 337.9 349.9 395.3 ab a ab ab ab b ab ab ab ab b ab ab ab a ab ab ab ab ab 88 Funding MPIC and MSU Treatment number Seed Treatment Treatment Application (amount per 1000 ft) Application timing z Rate of Emergence (RAUEPC) y Tuber number x Stem number x Stolon number x Marketable Yield cwt/A w 30.0 33.3 30.5 30.5 24.8 30.8 28.5 25.1 27.0 33.9 30.8 36.1 35.3 36.3 28.6 34.1 29.0 28.0 28.3 26.3 a a a a a a a a a a a a a a a a a a a a IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE 0.19 0.19 0.19 0.19 0.19 0.19 0.22 0.21 0.19 0.19 0.20 0.21 0.21 0.20 0.21 0.18 0.19 0.19 0.20 0.20 b b b b b b a ab b b abc ab a abc a c bc abc abc abc Amistar 80WDG 0.25 oz Moncut 70DF 1.18 oz Headline 0.21 fl oz Non-treated None Maxim 4FS v Amistar 0.25 oz 3.8 C 1 4.0 2 5.1 3 3.8 4 4.4 5 4.8 6 3.8 7 4.4 8 4.0 9 4.5 10 1 6.0 4.6 2 6.0 3 4.5 4 4.8 5 5.4 6 4.4 7 4.5 8 4.4 9 4.3 10 z Application timings: In-furrow at-planting (IF); at emergence (Em); 14 days post-emergence (PE) y RAUEPC: Relative area under the emergence progress curve (max = 100), calculated from the day of planting to 20 days after planting x Numbers of tubers, stems, and stolons are the average of 2 plants taken 50 days after planting w Marketable yield: all tubers greater than 2.5” in any plane (US1 grade), 90 days after planting v Maxim 4FS at Seed treatment at 0.08 fl oz/cwt u Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison) Moncut 70 DF 1.18 oz Headline 0.21 fl oz Non-treated 12.1 15.5 13.3 11.0 10.3 14.9 11.0 10.0 10.4 16.3 13.5 17.1 15.1 16.1 10.1 16.9 13.5 13.0 10.9 16.4 ab ab ab ab ab ab ab b ab a a a a a a a a a a a 250.8 242.1 261.5 255.8 226.4 240.5 219.6 155.6 247.1 232.1 191.6 228.1 194.3 209.3 237.8 250.4 177.9 220.3 224.6 191.9 ab ab a a ab ab ab b ab ab a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a 89 Funding MPIC and MSU Table 3a-c: The effect of seed treatment, fungicide application, and the timing of application; in-furrow at-planting (IF), emergence (Em), or 14 days post-emergence (PE) on disease symptoms caused by Rhizoctonia solani growth and development. Experiments located at A) Elmira, MI, ‘Superior’; B) Bath, MI, ‘FL1879’; C) Bath, MI, ‘Russet Norkotah’; 2004. Treatment number Seed Treatment Treatment Application (amount per 1000 ft) Application timing z Percentage of diseased Percentage of diseased Rhizoctonia incidence stems y stolons y Rhizoctonia severity on mature tubers w ab ab ab a ab b b b ab ab b b b b ab a b ab ab b ab u ab ab a ab ab b ab b ab a a a a a a a a a a IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE 9.1 13.3 12.6 23.2 12.2 1.0 7.7 4.0 8.0 15.7 3.3 2.7 3.6 2.1 3.8 8.5 1.8 4.5 4.5 1.5 24.5 24.7 24.0 41.7 37.5 16.7 14.1 20.2 13.5 26.6 16.9 15.8 13.0 12.2 11.3 8.3 8.2 7.8 6.9 6.4 Amistar 80WDG 0.25 oz Moncut 70DF 1.18 oz Headline 0.21 fl oz Non-treated None Maxim 4FS v Amistar 0.25 oz A 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 z Application timings: In-furrow at-planting (IF); at emergence (Em); 14 days post-emergence (PE) y Percent of stems and stolons with greater than 5% girdling caused by Rhizoctonia solani are from an average of 4 plants per replicate x Percent incidence of tubers with sclerotia of R. solani from a sample of 20 tubers per replicate taken 84 days after planting w Severity of black scurf (index calculated by counting the tuber number (n = 20 per replicate) falling into class 0 = 0%; 1 = 1 - 5%; 2 = 6 - 10%; 3 = 11 - 15%; 4 = >16% surface area. Indices of 0 to 25 cover the range 0 - 5%; 25 - 50 cover the range 6 - 10%; 51 - 75 cover the range 11 - 15%; 75 - 100 cover the range >15% surface area of the tuber with sclerotia (Taken 84 days after planting). v Maxim 4FS at Seed treatment at 0.08 fl oz/cwt u Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison) Moncut 70 DF 1.18 oz Headline 0.21 fl oz Non-treated 5.0 3.4 0.0 0.0 10.6 6.3 0.0 17.2 12.8 10.0 0.0 0.0 1.6 3.4 0.0 0.6 0.0 5.6 0.3 2.8 on mature tubers x ab 10.0 ab 7.5 b 0.0 b 0.0 23.8 ab ab 15.0 b 0.0 a 35.0 23.8 ab ab 20.0 a 0.0 a 0.0 3.8 a a 7.5 a 0.0 a 2.5 a 0.0 8.8 a a 1.3 7.5 a ab ab b b ab ab b a ab ab a a a a a a a a a a 90 Funding MPIC and MSU Application Percentage of diseased Percentage of diseased Rhizoctonia incidence timing z Treatment Seed Treatment number B 1 None 2 3 4 5 6 7 8 9 10 1 Maxim 4FS v 2 3 4 5 6 7 8 9 10 Treatment Application (amount per 1000 ft) Amistar 80WDG 0.25 oz Moncut 70DF 1.18 oz Headline 0.21 fl oz Non-treated Amistar 0.25 oz Moncut 70 DF 1.18 oz Headline 0.21 fl oz Non-treated IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE stem number y ab u 40.3 ab 38.5 ab 51.9 a 53.7 55.3 a ab 43.6 b 18.2 ab 31.4 a 64.4 50.4 ab ab 28.6 b 14.5 ab 32.9 40.3 ab ab 23.2 ab 43.1 a 54.1 26.9 ab b 11.9 38.2 ab stolon number y 41.8 abc abc 26.2 abc 25.6 ab 46.7 19.8 bc abc 32.4 c 14.8 a 53.3 abc 30.8 42.9 abc ab 23.1 b 10.2 ab 25.0 28.8 ab ab 27.8 ab 33.4 ab 24.3 25.3 ab ab 24.0 40.6 a on mature tubers x 38.8 72.5 58.8 62.5 70.0 43.8 53.8 81.3 75.0 67.5 47.5 77.5 57.5 60.0 55.0 61.3 65.0 63.8 50.0 53.8 c ab abc abc abc bc abc a ab abc a a a a a a a a a a Rhizoctonia severity on mature tubers w 18.4 38.4 29.4 29.7 39.1 22.8 24.7 44.7 39.4 35.9 21.9 41.9 31.3 28.8 29.1 32.2 30.6 35.0 25.3 24.4 b ab ab ab ab b ab a ab ab a a a a a a a a a a z Application timings: In-furrow at-planting (IF); at emergence (Em); 14 days post-emergence (PE). y Percent of stems and stolons with greater than 5% girdling caused by Rhizoctonia solani are from an average of two plants per replicate. x Percent incidence of tubers with sclerotia of Rhizoctonia solani from a sample of 20 tubers per replicate 90 days after planting w Severity of black scurf (index calculated by counting the tuber number (n = 20 per replicate) falling into class 0 = 0%; 1 = 1 - 5%; 2 = 6 - 10%; 3 = 11 - 15%; 4 = >16% surface area. Indices of 0 to 25 cover the range 0 - 5%; 25 - 50 cover the range 6 - 10%; 51 - 75 cover the range 11 - 15%; 75 - 100 cover the range >15% surface area of the tuber with sclerotia (Taken 90 days after planting). v Maxim 4FS at Seed treatment at 0.08 fl oz/cwt u Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison) 91 Seed Treatment None IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE stem number y 72.5 71.4 72.9 70.8 58.1 72.0 81.7 42.1 67.5 82.3 57.4 45.2 64.5 80.8 71.6 53.4 45.4 75.7 63.5 51.9 ab u ab ab ab ab ab a b ab a ab b ab a ab ab b ab ab ab stolon number y a 53.6 a 36.6 28.6 a a 31.5 a 31.2 a 54.9 a 30.5 38.0 a a 33.9 a 38.7 ab 31.1 22.2 ab a 37.3 a 41.8 ab 33.9 16.6 ab b 9.9 a 40.8 ab 22.8 29.7 ab Treatment Application (amount per 1000 ft) Amistar 80WDG 0.25 oz Moncut 70DF 1.18 oz Headline 0.21 fl oz Non-treated Amistar 0.25 oz Moncut 70 DF 1.18 oz Headline 0.21 fl oz Non-treated Treatment number C 1 2 3 4 5 6 7 8 9 10 1 Maxim 4FS v 2 3 4 5 6 7 8 9 10 z Application timings: In-furrow at-planting (IF); at emergence (Em); 14 days post-emergence (PE) y Percent of stems and stolons with greater than 5% girdling caused by R. solani are from an average of two plants per replicate x Percent incidence of tubers with sclerotia of R. solani from a sample of 20 tubers per replicate taken 90 days after planting w Severity of black scurf (index calculated by counting the tuber number (n = 20 per replicate) falling into class 0 = 0%; 1 = 1 - 5%; 2 = 6 - 10%; 3= 11 - 15%; 4 = >16% surface area. Indices of 0 to 25 cover the range 0 - 5%; 25 - 50 cover the range 6 - 10%; 51 - 75 cover the range 11 - 15%; 75 - 100 cover the range >15% surface area of the tuber with sclerotia (Taken 90 days after planting). v Maxim 4FS at Seed treatment at 0.08 fl oz/cwt u Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison) Rhizoctonia severity on mature tubers w 17.8 10.0 28.8 25.0 19.4 31.6 28.1 23.8 19.7 28.1 18.8 20.6 25.6 25.3 26.6 15.6 21.9 18.4 16.3 16.3 ab b a a ab a a ab ab a a a a a a a a a a a 42.5 30.0 57.5 48.8 45.0 62.5 63.8 53.8 51.3 56.3 43.8 45.0 55.0 56.3 53.8 40.0 50.0 48.8 37.5 37.5 ab b a ab ab a a ab ab ab a a a a a a a a a a Funding MPIC and MSU Application timing z Percentage of diseased Percentage of diseased Rhizoctonia incidence on mature tubers x 92 Funding MPIC and MSU Table 4: Effect of seed treatment on potato growth and development and yield; Experiments located at A) Elmira, MI, ‘Superior’; B) Bath, MI, ‘FL1879’; C) Bath, MI, ‘Russet Norkotah’; 2004 Variety and Location Seed Treatment Tuber number y Stem number y Stolon number y Rate of Emergence (RAUEPC) z b v a b a a a 0.42 0.45 0.13 0.15 0.20 0.20 16.2 22.1 35.4 40.3 29.4 31.3 b a a a a a 3.1 4.1 4.6 5.9 4.2 4.9 b a b a b a 13.4 19.2 44.4 52.1 12.5 14.3 b a a a a a Marketable Yield cwt/A x a 413.3 349.9 b a 420.9 a 441.2 a 306.2 313.4 a A B C Superior FL 1879 None Maxim 4FS w None Maxim 4FS Russet Norkotah None Maxim 4FS z RAUEPC: Relative area under the emergence progress curve (max = 100), calculated from the day of planting to 38 days after planting for “Superior,” calculated from the day of planting to 20 days after planting for “FL 1879” and “Russet Norkotah”. y Numbers of tubers, stems, and stolons are the average of 4 plants (per replicate) taken 50 days after planting for “Superior” and the average of 2 plants taken 50 days after planting for “FL 1879” and “Russet Norkotah”. x Marketable yield: all tubers greater than 2.5” in any plane (US1 grade), 84 days after planting for “Superior” and 90 days after planting for “FL 1879” and “Russet Norkotah”. w Maxim 4FS at seed treatment at 0.08 fl oz/cwt. v Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison). 93 A B C Superior FL 1879 Russet Norkotah Maxim 4FS w None None None Maxim 4FS Maxim 4FS 24.3 10.7 44.8 31.4 69.1 60.9 a v b a b a a due to R. solani z 10.7 a b 3.6 a 33.4 a 26.2 37.8 a b 28.6 on tubers (%) y 13.5 a b 3.1 a 62.4 a 59.1 51.1 a a 46.8 scurf on tubers x 6.5 a b 1.4 a 32.3 a 30.0 23.2 a a 20.5 Funding MPIC and MSU Table 5: Effect of seed treatment on disease symptoms caused by Rhizoctonia solani growth and development; Experiments located at A) Elmira, MI, ‘Superior’; B) Bath, MI, ‘FL1879’; C) Bath, MI, ‘Russet Norkotah’; 2004 Percent stems with greater than 5% girdling due to R. solani z Incidence of black scurf greater than 5% girdling Variety and Location Percent stolons with Seed Treatment Index of severity of black z Percent of stems and stolons with greater than 5% girdling caused by R. solani are from an average of 4 plants per replicate for ‘Superior’ and an average of 2 plants per replicate for ‘FL1879’ and ‘Russet Norkotah’ y Percent incidence of tubers with sclerotia of R. solani from a sample of 20 tubers per replicate taken 84 days after planting for “Superior” and 90 days after planting for “FL 1879” and “Russet Norkotah” x Severity of black scurf (index calculated by counting the tuber number (n = 20 per replicate) falling into class 0 = 0%; 1 = 1 - 5%; 2 = 6 - 10%; 3 = 11 - 15%; 4 = >16% surface area. Indices of 0 to 25 cover the range 0 - 5%; 25 - 50 cover the range 6 - 10%; 51 - 75 cover the range 11 - 15%; 75 - 100 cover the range >15% surface area of the tuber with sclerotia (Taken 84 days after planting for “Superior” and 90 days after planting for “FL 1879” and “Russet Norkotah” ). w Maxim 4FS at Seed treatment at 0.08 fl oz/cwt v Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison) 94 Funding MPIC and MSU Table 6: The effect of seed treatment and the timing of application of fungicides in-furrow at-planting (IF), emergence (Em), or 14 days post-emergence (PE) on potato growth and development and yield. Experiments located at A) Elmira, MI, ‘Superior’; B) Bath, MI, ‘FL1879’; C) Bath, MI, ‘Russet Norkotah’; 2004. Variety and Location Seed Treatment Application timing z A B C Superior None Maxim 4FS v FL1879 None Russet Norkotah Maxim 4FS v None Maxim 4FS v IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE Rate of Emergence (RAUEPC) y a u a a b a a a a a a a ab a 0.40 0.43 0.42 0.42 0.46 0.45 0.13 0.12 0.13 0.16 0.16 0.15 0.20 0.20 0.19 0.19 0.20 0.20 a a a a a Tuber number x Stem number x Stolon number x 15.8 18.7 15.6 23.0 21.8 22.4 37.5 35.9 35.0 42.5 36.2 41.9 29.7 27.7 29.4 32.0 30.9 32.5 a a a a a a a a a a a a a a a a a a 3.1 3.3 3.1 4.1 4.0 4.2 5.3 4.6 4.3 6.5 5.8 5.4 3.8 4.3 4.6 5.0 4.6 5.3 a a a a a a a a a a a a a a a a a a 12.3 14.9 13.8 19.6 19.5 19.5 49.9 44.2 42.4 60.5 46.9 52.0 11.4 11.9 12.8 14.4 13.4 14.3 b a ab a a a a a a a a a a a a a a a Total MaketableYield cwt/A w a b ab a a a a a a a a a a 432.1 391.0 417.8 348.4 335.2 358.4 372.0 392.5 369.4 359.1 366.1 364.8 242.0 208.0 249.7 192.9 228.7 223.1 a a a a a z Application timings: In-furrow at-planting (IF); at emergence (Em); 14 days post-emergence (PE) y RAUEPC: Relative area under the emergence progress curve (max = 100), calculated from the day of planting to 20 days after planting x Numbers of tubers, stems, and stolons are the average of 2 plants taken 50 days after planting w Marketable yield: all tubers greater than 2.5” in any plane (US1 grade), 90 days after planting v Maxim 4FS at Seed treatment at 0.08 fl oz/cwt u Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison) 95 Funding MPIC and MSU Table 7: The effect of seed treatment and the timing of application of fungicides in-furrow at-planting (IF), emergence (Em), or 14 days post-emergence (PE) on disease symptoms caused by Rhizoctonia solani growth and development. Experiments located at A) Elmira, MI, ‘Superior’; B) Bath, MI, ‘FL1879’; C) Bath, MI, ‘Russet Norkotah’; 2004. Variety and Location Seed Treatment Application timing z Percentage of diseased stem number y Maxim 4FS v None None Maxim 4FS v Maxim 4FS v IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE IF Em PE 26.7 27.5 18.1 8.8 7.5 13.7 37.4 41.8 53.3 41.0 21.5 29.3 75.0 57.2 70.8 61.2 64.2 60.5 Percentage of diseased stolon number y a a a b ab a a a a a a a a a a a a a 13.3 9.8 7.2 2.4 3.7 5.5 34.4 33.1 29.6 25.4 21.1 27.5 38.5 35.3 39.2 27.6 32.3 25.6 Rhizoctonia incidence Rhizoctonia severity on mature on mature tubers x 3.3 22.1 12.9 2.5 2.9 2.5 51.7 74.6 59.2 57.5 65.4 56.3 51.7 42.9 57.1 50.0 49.2 44.2 b a ab a a a b a ab a a a a a a a a a tubers w a a a a a a b a ab a a a ab b a a a a 1.7 10.4 6.4 1.1 1.9 0.8 24.3 40.7 30.5 27.1 35.3 29.6 23.6 17.7 26.7 22.0 21.9 19.2 a a a a a a a a a a a a a a a a a a A B C Superior FL1879 Russet Norkotah None z Application timings: In-furrow at-planting (IF); at emergence (Em); 14 days post-emergence (PE) y Percent of stems and stolons with greater than 5% girdling caused by R. solani are from an average of 4 plants per replicate for ‘Superior’ and an average of 2 plants per replicate for ‘FL1879’ and ‘Russet Norkotah’ x Percent incidence of tubers with sclerotia of R. solani from a sample of 20 tubers per replicate taken 84 days after planting for “Superior” and 90 days after planting for “FL 1879” and “Russet Norkotah” w Severity of black scurf (index calculated by counting the tuber number (n = 20 per replicate) falling into class 0 = 0%; 1 = 1 - 5%; 2 = 6 - 10%; 3 = 11 - 15%; 4 = >16% surface area. Indices of 0 to 25 cover the range 0 - 5%; 25 - 50 cover the range 6 - 10%; 51 - 75 cover the range 11 - 15%; 75 - 100 cover the range >15% surface area of the tuber with sclerotia (Taken 84 days after planting for “Superior” and 90 days after planting for “FL 1879” and “Russet Norkotah” ). v Maxim 4FS at Seed treatment at 0.08 fl oz/cwt u Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison) 96 Funding MPIC and MSU Table 8: Effect of variety and planting time on incidence and severity of sclerotia on potato tubers of different varieties caused by Rhizoctonia solani, East Lansing, MI. Timing 1 z Timing 2 y Timing 3 x Severity v Incidence w a u 89.4 100.0 a a 91.2 a 69.8 a 61.6 95.8 82.8 a a Severity v ab a ab b b 18.8 29.5 22.1 16.1 10.9 19.4 14.6 ab b Incidence w b 15.6 38.6 ab b 17.7 ab 39.3 13.3 b 62.8 15.7 a b Severity v b ab b ab b 3.0 6.9 2.2 7.2 1.6 3.0 3.1 a b Incidence w ab 29.0 10.0 bc bc 7.6 c 2.4 ab 15.2 0.0 9.0 c bc 6.8 1.6 1.3 0.4 2 7.2 1.5 0.6 8.3 abc bcd bcd cd ab d bcd bcd a Variety Atlantic FL 1833 FL 1867 FL 1879 Jacqueline-Lee Michigan Purple Pike Russet Norkotah Snowden 90.8 80.3 a a 17.7 17.1 ab b 4.2 26.7 b ab 0.4 4.3 b ab 5.7 37.0 bc a z Timing 1: planting done once soil temperatures at 4 inch depth reached 8oC. y Timing 2: planting done once soil temperatures at 4 inch depth reached 14oC. x Timing 3: planting done once soil temperatures at 4 inch depth reached 20oC. w Percent incidence of tubers with sclerotia of R. solani from a sample of 4 plants per replicate taken 25 October v Severity of black scurf (index calculated by counting the tuber number falling into class 0 = 0%; 1 = 1 - 5%; 2 = 6 - 10%; 3 = 11 - 15%; 4 = >16% surface area. Indices of 0 to 25 cover the range 0 - 5%; 25 - 50 cover the range 6 - 10%; 51 - 75 cover the range 11 - 15%; 75 - 100 cover the range >15% surface area of the tuber with sclerotia. u Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison). Table 9: Effect of planting time on incidence and severity of sclerotia on potato tubers of different varieties caused by Rhizoctonia solani, East Lansing, MI Time of planting z Incidence of tuber black Severity of tuber black scurf y scurf x 1 2 3 85.6 25.4 14.4 aw b b 43.6 14.3 10.0 a b b z Timing 1, 2 and 3, planted when soil temperatures at 4 inch depth reached 8, 14 and 20oC, respectively. y Percent incidence of tubers with sclerotia of R. solani from a sample of 4 plants per replicate taken 25 October x Severity of black scurf (index calculated by counting the tuber number falling into class 0 = 0%; 1 = 1 - 5%; 2 = 6 - 10%; 3 = 11 - 15%; 4 = >16% surface area. Indices of 0 to 25 cover the range 0 - 5%; 25 - 50 cover the range 6 - 10%; 51 - 75 cover the range 11 - 15%; 75 - 100 cover the range >15% surface area of the tuber with sclerotia. w Values followed by the same letter are not significantly different at a = 0.05 (Student's Pairwise Comparison). 97 Funding: MPIC, MSU and Industry Host Plant Resistance and Reduced Rates and Frequencies of Fungicide Application to Control Potato Late Blight (Co-operative trial Quad State Group 2004). W.W. Kirk1, F. Abu El-Samen1, D.S. Douches2, C. Thill3, J. Jang4 and A. Thompson5. 1Plant Pathology, 2Crop and Soil Sciences, Michigan State University, 3Crop Science, University of Minnesota, 4University of Wisconsin, 5North Dakota State University. INTRODUCTION following strategies changed late blight control Late blight of potato caused by Phytophthora infestans (Mont de Bary), is a major threat to the production of high quality potatoes. Unchecked, P. infestans can rapidly defoliate plants in the field and can infect potato tubers when spores are washed into the soil. Potato the migration of mefenoxam/metalaxyl-resistant populations of P. infestans from Mexico to North America and necessitate cultural control methods and crop protection strategies that rely primarily on protectant foliar fungicide applications. 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. There are currently few late blight resistant potato cultivars that meet commercial standards in the United States. 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. 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. In the present study, any cultivar/ABL with foliar late blight severity measured as the Relative Area Under the Disease Progress Curve [RAUDPC] value that was not significantly higher than that of Torridon was classified as late blight resistant (R). Any cultivar/ABL with a RAUDPC value significantly higher than that of Snowden or with a RAUDPC value that was not statistically different from that of Atlantic 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 Torridon but significantly lower than that of Snowden. The cultivars/ABL included in the trials from 2004 are listed in Table 1. 98 Residual Contact Fungicides Omega 5SC (Syngenta) was used for this experiment. Fungicides were applied with an ATV rear-mounted spray boom (R&D Sprayers, Opelousas, LA) 20 gal H2O/A (80 psi pressure) with three XR11003VS nozzles per row positioned 12” apart and 18” above the canopy. In the fungicide application interval and reduced dose rates trial, Omega 5SC was applied at 5, 10 and 15 day intervals at 0, 50 and 100% MRAR to the ABL and cultivars described in Table 1. The first fungicide application occurred at 24 days after planting (DAP) (21 Jul 2004) when potato plants were approximately 6” tall. Fungicides were applied until non-treated plots of susceptible controls reached about 100% diseased foliar area (4 Sep). The 5, 7, 10 and 15-day interval treatments received nine, seven, five and three applications in 2004, 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 28, 2004 in two-row by 50 ft plots (34” row spacing). Fertilizers were applied in accordance with results from soil testing carried out in the spring of each year and about 200 cwt N/A (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 cwt/A boron, manganese and magnesium, respectively were applied as chelated formulations. Cut and whole seed pieces (2.5 -5.0 oz) 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 Torridon 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 canopy and soil moisture conditions conducive for development of foliar late blight with turbine rotary garden sprinklers (Gilmour Group, Somerset, PA, U.S.A.) at 112 gal H2O A/hr and managed under standard potato agronomic practices. Weeds were controlled by hilling and with Dual 8E (2 pt/A on 28 Jun), Basagran (2 pt/A on 28 Jun and 25 Jul) and Poast (1.5 pt/A on 25 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 28 Jun), Sevin 80S (1.25 lb/A on 11 and 25 Jul), Thiodan 3EC (2.33 pt/A on 1 and 21 Aug) and Pounce 3.2EC (8 oz/A on 25 Jul). 99 Pathogen Preparation and Inoculation. Zoospore suspensions were made from P. infestans cultures of several isolates from different genetic backgrounds, including [US8, US14 and US17 genotypes, with a mixture of sensitivity to mefenoxam/metalaxyl, but A2 mating types (13)], the predominant genotypes present in the major potato growing regions of North America (12), grown on rye agar plates 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 102 sporangia/fl oz using a hemacytometer. Sporangial cultures were incubated for 2-3 hours at 40oF to stimulate zoospore release. All plots were inoculated simultaneously through an overhead sprinkler irrigation system, on July 30, 2004; by injecting the zoospore suspension of P. infestans into the irrigation water feed pipeline under 20 psi CO2 pressure and applied at a rate of about at 104 spores/fl oz on 30 Jul over the whole 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 (45 DAI in 2004). Days after inoculation were used as a key reference point for calculation of Relative Area Under the Disease Progress Curve [RAUDPC]. Microclimate Measurement Climatic variables were measured with a Campbell Weather Station equipped with air temperature and humidity sensors located within the potato canopy on site. 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 Wallin Late Blight Prediction Model 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 48 DAI. Maximum and minimum air temperature (oF) were 88.2 and 67.2 (Jun), 87.5 and 67.7 (Jul), 88.1 and 67.7 (Aug) and 85.3 and 66.0 (Sep). Maximum and minimum soil temperature (oF) were 74.5 and 69.8 (Jun), 77.0 and 71.9 (Jul), 78.0 and 71.4 (Aug) and 75.9 and 70.2 (Sep). Maximum and minimum soil moisture (% of field capacity) was 98.5 and 95.8 (Jun, severe flooding); 98.1 and 63.3 (Jul), 85.4 and 71.4 100 (Aug) and 76.8 and 79.8 (Sep). Precipitation was 4.04” (Jun), 3.68" (Jul), 1.83" (Aug) and 0.93" (Sep). The total number of late blight disease severity values (DSV) over the inoculation period was 116 and 44 (using 80% and 90% ambient %RH as bases for DSV accumulation), respectively (Figure 1). Plots were irrigated to supplement precipitation to about 0.1”/A/4 day period with overhead sprinkle irrigation. This indicated that environmental conditions were conducive to late blight development (DSV > 18). The lower and upper thresholds used to determine the efficacy of the fungicide and variety combination programs were RAUDPC = 1.4 and 25.3 (7-day 100%MRAR and non-treated, Snowden), respectively. Therefore, fungicide treatment and variety combinations with an RAUDPC NSD from Snowden, 100% MRAR, 7-day application interval, RAUDPCSF7) were defined as effective (E); combinations NSD from the non-treated Snowden control (RAUDPC = 25.3) were defined as non-effective (NE); and combinations with RAUDPC values significantly different from both standards were defined as partially effective (PE); (Table 1). Application of Omega 5SC at 50% and full rate of application at a 5 or 7-day interval resulted in effective control of late blight in all varieties. The mean RAUDPC for non- treated MSJ461-1 and Torridon ranged from 0.0 to 0.3, which were classified as resistant. Fungicide treatments did not significantly effect late blight development in either MSJ461-1 or Torridon. All cvs. /ABL were effectively protected by application of the fungicide at 50 and 100% MRAR on 5 or 7 -day intervals. The cvs./ ABL MN15620R/-yel and Villetta Rose were PE on a 10-day interval at both rates of fungicide application. Late blight was partially effectively controlled by both rates of application at a 15-day interval in Atlantic and at 50% MRAR in Freedom Russet. Late blight was not effectively controlled in Dakota Jewel (50% MRAR) at either rate of fungicide application in MN15620R/-yel on a 15-day application interval. 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. When conditions were conducive to late blight development (as in 2004), reduced amounts of fluazinam were either fully or partially effective at most application rates tested on all cultivars/ABL compared to the non-treated controls. However. in some cultivars/ABL, 50% of the MRAR of 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 usually partially effective for controlling late blight at the doses tested. However, in the resistant cultivars Torridon and MSJ461-1 the fungicides did not reduce the RAUDPC in comparison with untreated plots of these cultivars and fungicides are not required for late blight control in these entries. 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 101 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. 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. 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, National Potato Council 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. ACKNOWLEDGMENTS 102 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 2004. Cultivar/ABL1 Application frequency (days) Rate of 0 5 7 10 15 fluazinam2 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 S I R S S S RAUDPC3 24.6 ab4 S5 25.0 ab 16.2 b-e 0.0 n 23.6 ab 23.4 ab 25.3 a 0.6 mn R 23.2 ab S 13.2 d-k PE 10.0 c-g PE 21.6 a-c NE 5.1 d-l E 12.1 d-i PE f-n E 6.5 0.0 n E E 0.0 n 0.5 mn E 0.2 mn E 2.3 k-n E 1.4 k-n E 1.9 k-n E E 0.3 n 0.0 n E E 0.0 n 6.3 f-n E 1.6 k-n E . l-n E 0.6 E 0.1 n 1.4 k-n E l-n E 0.7 E 0.1 n 0.0 n E l-n E 0.7 0.3 n E E6 0.3 n 0.6 mn E 1.8 k-n E 0.6 mn E l-n E 0.7 E 0.3 n 0.0 n E E 0.0 n 3.5 i-n E 0.6 mn E E 0.3 n E 0.1 n 0.9 l-n E 0.4 mn E E 0.1 n 0.0 n E 0.2 n E 0.4 mn E j-n E 3.1 l-n E 1.0 7.1 g-n E f-n E 9.3 4.2 h-n E 3.2 j-n E 0.0 n E E 0.0 n 14.1 c-f PE 17.0 a-e NE 14.0 c-f PE 17.4 a-d NE 2.4 k-n E E 0.2 n 4.0 k-n E 2.0 h-n E E 0.1 n 0.1 n E 9.1 d-h PE 12.3 d-m PE 7.2 d-j PE 11.6 f-n PE Atlantic Dakota Jewel Freedom Russet MSJ461-1 MN15620R/-yel ND5822C-7 Snowden Torridon Villetta Rose 1 Varieties and advanced breeding lines from the Quad State potato breeding programs. 2 Application rate of fluazinam as percent of manufacturer’s recommended rate (full rate = 0.6 pt/A) 3 Relative area under the disease progress curve from inoculation to 100% late blight in susceptible control (Snowden); max = 100. 4 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. 5 Susceptibility of non-treated control to late blight; R = Resistant, not significantly different from Torridon (non-treated); S = Susceptible, not significantly different from Snowden (non-treated); I = Intermediate, significantly different from both Torridon and Snowden (non-treated). 6 Effectiveness of fungicide treatment in comparison to Snowden treated with a full application rate of fluazinam at a 5-day interval or with non-treated Snowden control; E = RAUDPC NSD from treated Snowden control; PE significantly different from treated Snowden control and non-treated control; NE = NSD from Snowden non-treated control at p = 0.05. . 3.9 l-n E 1.2 h-n E 8.4 e-n E f-n E 5.7 E 0.1 n 0.1 n E 103 Funding: MPIC, MSU and Industry Evaluation of Tuber Late Blight Response of potato cultivars and advanced breeding lines and their potential to reduce seed-borne epidemics of late blight. Michigan State University 2003 – 2004. Dr. Willie Kirk1, Dr. Firas Abu-EL Samen1, Dr. Ray Hammerschmidt1, and Dr. Dave Douches2. 1Department Plant Pathology, 2 Crop and Soil Science, MSU, East Lansing, MI 48824, phone: 517 353 4481,e-mail: kirkw@msu.edu. Introduction Late blight of potato, caused by Phytophthora infestans, is a major worldwide threat to the production of high quality potatoes. Late blight is readily transmitted by seed-borne inoculum (Kirk et al. 1999) and consequently, immature stems and leaves may be exposed to late blight from infected seed pieces. Recent work has indicated that the new immigrant clones, especially US-8 genotype, are more aggressive in tubers and sprouts. The new genotypes of late blight are 10 times more likely to produce infected sprouts than their predecessor, US-1 (Stevenson, 1993). Potato breeding efforts at MSU have resulted in varieties that are largely resistant to foliar late blight (Kirk et al 2001a) but not significantly less susceptible than other varieties in terms of tuber blight resistance (Kirk et al. 2001b). The transmission dynamics of late blight inoculum from seed to sprout and ultimately to the stem are still largely unknown and have been tested with only a limited number of varieties of potato and isolates of P. infestans. In this study, advanced breeding lines (MSU and other germplasm sources) will be evaluated for resistance to tuber blight. Subsequently, tubers will be under seed storage conditions and after storage prepared for planting by increasing temperature in the storage. Transmission of late blight from seed to foliage will be evaluated and potential risk measured. Potentially, the release of varieties with resistance to foliar and tuber blight will be of great economic benefit to the industry and to the environment and reduces the risk of threats to food security. Objectives 1. Evaluate late blight response of potato tubers of advanced breeding lines from the MSU and other potato breeding programs to the US-8 genotype of P. infestans. 2. Evaluate the potential for late blight to be transmitted from seed to foliage in potato cultivars and advanced breeding lines to a variety of P. infestans genotypes. 3. Evaluate late blight response of potato tubers from different cultivars and advanced breeding lines using five different genotypes of the late blight pathogen (P. infestans). Materials and methods Tubers for the experiments were obtained from the potato breeding program at MSU and breeding programs in Wisconsin, Minnesota and North Dakota. Potato tubers were stored at 38oF (3oC) in the dark at 90% relative humidity until used. Tubers for all the experiments were within the size grade range 50 - 150 mm diameter (any plane). Visual examination of a random sample of tubers from each entry (n = 2) for disease symptoms indicated that the tubers were free from late blight. The sample was further tested with the ELISA immuno-diagnostic Alert Multi-well kit (Alert Multiwell Kit - Phytophthora sp. Neogen Corporation, Lansing, MI, USA). P. infestans was not detected in any of the tubers. Three experiments were carried out in this study and were repeated in 2003 and 2004. In experiment (1), potato tubers from cultivars and advanced breeding lines were evaluated for tuber blight susceptibility against the US-8 genotype 104 of P. infestans. In this experiment, tubers were inoculated followed by storage at 50oF (10oC) for 30 days and blight severity was evaluated by an image analysis technique. In experiment (2), sixteen potato cultivars and ABL were inoculated with five different genotypes of P. infestans (US-1, US-6, US-8, US-11 and US-14) into a freshly cut tuber surface, incubated for 5 days at 50F (10oC), then planted at the Muck Soils Research Farm, Laingsburg, MI and plant emergence and foliar late blight was evaluated. In experiment (3), tubers from potato cultivars and ABL used in experiment 2 were inoculated as in experiment 2 and were incubated for 30 days at 50oF (10oC). Tubers were then cut and evaluated for blight severity using image analysis technique. P. infestans culturing and inoculations: Cultures of P. infestans were propagated on rye agar petri plates for 14 days in the dark at 17oC. Prior to inoculation, all tubers were washed in distilled H2O to remove soil. The tubers were then surface sterilized by soaking in 2% sodium hypochlorite (Clorox 5.25%) solution for 30 min. Tubers were dried in a controlled environment with continuous airflow at 15oC in dry air (30% relative humidity) for four hours prior to inoculation. Tuber tissue inoculation Experiment 1 Evaluation of potato cv/ABL tuber susceptibility to US-8 genotype Sporangia were harvested from the petri dishes by rinsing the mycelium/sporangia mat in cold (4oC) sterile, distilled H2O and scraping the agar surface with a rubber policeman. The mycelium/sporangia suspension was stirred with a magnetic stirrer for 1 hour. The suspension was strained through four layers of cheesecloth and sporangia concentration was adjusted to about 1 x 106 total sporangia ml-1 (discharged and non-discharged) with the aid of a haemacytometer. The sporangial suspensions were stored for 2 h at 4oC to encourage zoospore release from the sporangia. The washed, surface-sterilized tubers were inoculated by a sub- peridermal injection of a sporangia suspension of 2 x 105 ml -1 with a hypodermic syringe and needle at the apical end of the tuber about 1 cm from the dominant sprout to a maximum depth of 1 cm. In total fifty five cultivars and ABL were tested in 2003 and forty nine in 2004 (Table 1). Ten tubers from each cultivar/ABL were inoculated as above and were incubated in a temperature-controlled environment chamber, 1.8 m3 volume (Environmental Growth Chambers, Chagrin Falls Ohio, USA) at 50oF (10oC). Three replicates per cv/ ABL were inoculated. In total 30 tubers were tested for each cultivar or ABL. Relative humidity was maintained at 90% within the chamber. The non-inoculated control tubers (n=10 x 3 rep.) were inoculated with cold (4oC) sterile distilled H2O and incubated under the same conditions as above. Experiment 2 Blight Transmission in seed tubers As in experiment 1, but a smaller number of cultivars/ ABL were inoculated with five different genotypes of Phytophthora infestans, US1, US6, US8, US11 and US14. Sixteen cultivar/ABL were inoculated with P. infestans genotypes (Table 2). The seed tuber was cut into two pieces with a sterile knife. The exposed cut surface was placed face down on a 14 day old, homogenized mixture of mycelium and sporangia of P. infestans in rye agar for 30 s. The homogenate was prepared from 20 plate cultures (9 cm diameter x 15 mm depth petri plates). Each plate produced between 105 - 106 spores ml-1 from 50 ml of wash water. An estimate of the 105 amount of mycelium from each plate was not attempted. Following inoculation tubers were incubated for 5 days at 50oF (10oC). Tubers (n=8 per cv./ABL) were then planted at the MSU Muck Soils research Farm and irrigated with adequate moisture to allow emergence. Plant stand, rate of emergence and foliar late blight especially on stems, and immature foliage were evaluated. Experiment 3 Evaluation of blight severity in storage at 10C Potato cultivars and advanced breeding lines used for the transmission experiment (experiment 2) were evaluated for tuber blight in storage. Tubers were inoculated in the same manner as in experiment 2 and were then stored in the dark in net bags within ventilated plastic boxes (8 tubers/box). Disease development rates within tubers in relation to storage temperature were known from previous experiments and a single sampling date was selected about 30 days after inoculation (DAI). Sample size was n = 8 tubers plus 8 control tubers per variety/genotype combination. Tuber blight severity measurements with digital image analysis A digital image analysis technique was used to assess tuber tissue infection. Briefly, the scanned surface was the cut face of a sample tuber. A sharp knife was used to ensure a smooth cut face. Fresh-cut tuber sections were placed cut 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 plate was transferred to a flatbed scanner (Epson perfection 4870) controlled by PC. Scanner control software (Adobe Photoshop version 7.0) generated an image of the cut tuber surfaces against a black background. The image was formed from light reflected from the cut tuber 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 size of the pale tuber surfaces against the black background. A photograph-quality image was taken and stored for analysis (e.g. Fig. 1). A typical image in Tagged Image Format (*.tif) occupies 1 megabyte. Typical ARI values for a range of infected and uninfected cut tuber surfaces were shown on Figure 1. The image files created with the scanner software were loaded into the image analysis software (Sigma Scan Pro ver. 5.0, Jandel Scientific, San Rafael, CA). The black background has 0 light intensity units (LIU), while pure white has 255 LIU. Disease-free and blemish-free tuber tissue is pale. Diseased or blemished tuber tissue is darkened. The image of the cut tuber surface was selected for analysis, and isolated from the adjacent regions of the image. The image was carefully cropped for irregularly shaped tubers to remove the image of the adjacent tuber skin, and the image of the cut surface was unedited. The area was selected with the Afill@ 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 infection severity of the tuber tissue of each sample. The ARI was measured in sections from the apical, middle and basal regions of the tuber, approximately 25% (apical), 50% (middle) and 75% (basal) of the length of the tuber (respectively) as measured from the apical end. The amount of late blight infected tissue per 106 tuber was expressed as a single value (Mean ARI) calculated as the average ARI of the apical, middle and basal sections evaluated 30 DAI. Tuber rot severity was expressed relative to the ARI of the non-inoculated treatments for each cv./ABL. Relative average reflective intensity of a treatment was calculated as follows: % RARI = [1- Mean ARI treatment / Mean ARI control] *100; % RARI has a minimum value of zero (no visible symptoms) and maximum value of 100 (Tuber surface is completely blackened). Data were analyzed by analysis of variance ANOVA using SAS program. Data Analysis The presence of P. infestans in sample tubers was confirmed by ELISA (described above) and by isolating pure cultures of P. infestans from the infected tuber tissue and successful re- inoculation of potato tubers and leaves. Treatment effects were determined by ANOVA, and grouped as most susceptible within the parameters of the varieties sampled. Cultivars and ABL were considered resistant to tuber blight if their RARI values were not significantly different from the least susceptible cultivar or ABL among the cv./ABL evaluated. Cultivars and ABL were considered susceptible if their RARI values were not significantly different from the most susceptible cv/ABL. Cultivars and ABL that were significantly different from both the most susceptible and least susceptible cv/ABL were considered moderately susceptible. All comparisons were made relative the cv/ABL included in each experiment. For experiment 1, the mean RARI of individual tubers was compared to that of non-inoculated controls of the same variety/ABL. For experiment 2, the number of emerged plants was measured over a 60 day period after planting and the final plant stand and relative area under the emergence progress curve was calculated. For experiment 3, comparisons were made among different genotypes within individual cvs. /ABL. Results Experiment 1 In both 2003 and 2004 trials, cultivars and ABL tested demonstrated variable levels of susceptibility to tuber late blight. In 2003 the relative average reflective intensity values of tubers had a minimum value of 4.3 (ABL WTS 1212-6) and maximum of 35.8 for the cultivar Russet Norkotah. Significant differences in tuber susceptibility were observed among different cv./ABL and were accordingly categorized into three classes (susceptible, moderately susceptible and resistant). Cultivars and ABL that were not significantly different form the most susceptible cultivar/ABL (Russet Norkotah in 2003) were classified as susceptible. This included 10 cv./ABL that had RARI values of 26.9-35.8. Cultivars and ABL that were not significantly different from the least susceptible cv/ABL (ABL WTS 1212-6) were classified as resistant (16 cv/ABL) (Table 1), these cvs/ABL had a RARI values of 4.3 to 12.4. Other cvs./ABL that were significantly different from both the most susceptible and least susceptible cv/ABL were classified as moderately susceptible ( 28 cv/ABL) (Table 1). Similarly In 2004 trial the cvs./ABL had a wide range of susceptibilities to tuber blight and were classified in the same manner as in 2003 trial. The advanced breeding line MSK027C had the lowest RARI value of 6.5, while the ABL Fl1922 had the highest RARI value of 34.7. Cultivars and ABL were categorized according to their significant differences of RARI values 107 from the most susceptible and least susceptible cv/ABL. Accordingly the resistant cv/ABL are those with RARI values between 6.5 and 14.9 which included 3 cv/ABL. The susceptible cvs/ABL were those that were not significantly different from the most susceptible advanced breeding line FL 1922. The range of RARI for this category was 27.1-34.7. Other cvs./ABL were classified as moderately susceptible and had a rang of RARI of 14.9 to 26.1 (Table 1). Experiment 2 The analyses of variance indicated that overall the US-8 genotype was the most virulent and aggressive of those tested reflected by poor emergence and plant stand across most cvs/ABL in both 2003 and 2004 trails, followed by the US14 genotype (Table 2 & 3). The US1 and US6 genotypes were rarely virulent and were the least aggressive causing only moderate reductions in emergence across cvs/ABL (Table 2 & 3). The rate of emergence and number of plants emerged was significantly different from the non-inoculated control for most cv/ABL inoculated with US8 and US14. Cultivars and ABL inoculated with other genotypes (US11, US6 and US1) were in most cases not significantly different from the non-inoculated controls (Tables 2, 3, 4). There is a wide range in tuber susceptibility to US8 which is clearly a virulent and aggressive genotype of P. infestans. As U8 is the predominant genotype of P. infestans in North America it would be prudent to continue to screen and develop novel sources of resistance including germplasm from other sources. However, as US8 suddenly appeared and quickly impacted potato production significantly during the 1990s, it would also be prudent to screen promising cultivars/ABL for their reaction to other genotypes of P. infestans. Despite that most cultivars and ABL inoculated with the US-8 genotype had poor emergence and high rate of tissue rotting and deterioration, there were some cases in some cultivars and ABL were emergence occurred (e.g. Fl1867, Torridon and Snowden). These emerged plants, although small percentage had a potential to start an epidemic in the field. However, foliar symptoms of late blight were not detected in 2003 or 2004 trails. Experiment 3 The rate of tuber tissue rotting and discoloration after inoculation with different genotypes was evaluated 30 days post inoculation. Cultivars and ABL demonstrated variable responses to different genotypes of P. infestans. Consistent with results from the transmission experiment (experiment 2) the US-8 genotype caused the highest level of tuber rotting as observed from the values of RARI of scanned tuber sections in both 2003 and 2004 trials (Tables 5 & 6). However values of RARI where higher in 2003 compared to 2004. In 2003 trial values of RARI ranged from 0 to 42.72 while in 2004 the RARI values were between 0 and 28.33 (Tables 5,6). The US-6 and US-1 genotypes caused the lowest level of tuber rotting in all cultivars and ABL tested. In 2003 trial, among the cv./ABL tested, the cultivar Pike demonstrated the highest level of tuber rotting across all P. Infestans genotype with mean RARI value of 36.15, followed by the cv./ABL I157-A, J317-1, Jacqueline Lee, J319-A, J461-A, Torridon, J319-7, Fl 1879, J453-4Y, Atlantic and J456_Y respectively (Table 5). In 2004, trial the cv. Atlantic demonstrated the highest level of tuber resistance against P. infestans across all genotypes tested with mean RARI value of 0.71. The highest level of tuber susceptibility occurred in the ABL MN 98642 with mean RARI value of 9.42 across all genotypes tested. 108 Table 1. Susceptibility of tubers of potato cultivars/ABL to the US8 genotype of Phytophthora infestans. Cultivar/ABL 2004 FL1922 RARI 34.70 32.20 32.00 31.30 29.40 28.00 27.10 26.10 25.60 25.50 25.40 24.00 24.00 23.80 23.60 23.60 23.50 23.20 22.80 21.90 21.80 21.70 21.40 21.10 20.40 20.20 20.20 20.10 19.40 19.00 18.80 18.70 18.70 18.70 18.60 18.20 17.60 17.40 17.20 16.80 16.80 16.60 16.30 15.60 14.90 a S a-b S a-b S a-c S a-d S a-e S a-f S b-g S b-h S b-h S b-h MS c-i MS c-i MS c-i MS c-i MS c-i MS c-i MS d-j MS d-j MS d-k MS d-k MS d-k MS e-l MS e-l MS e-l MS e-l MS f-l MS MS f-l f-l MS g-l MS g-l MS g-l MS g-l MS g-l MS g-l MS h-l MS i-l MS i-m MS i-m MS i-m MS i-m MS i-m MS i-m MS j-m MS k-m R FL1879 Tuber late blight susceptibility index Cultivar/ABL 2003 Russet Norkotah Snowden MSJ462-AB MSJ343-1 MSJ456-2Y MSJ319-7 MSJ319-1 MSJ317-1 MSK101-2 MSJ453-4Y Atlantic MSJ334-2Y MSJ461-1 MSJ453-4YA MSK136-2A MSJ462-A MSJ438-2 MSI157-A CIPLBR 46 MSJ307-2 CIPLBR 50 MSK136-2 AWN86514-2 MSK 458-2 ho26-3rus WTS 1210-4 CIPLBR 24 MSKO34-1 Jacqueline Lee. Lee MSJ464-5 MSJ457-2 MSJ456-4Y Torridon MSK128-1 BO718-3 CIPLBR 33 CIPLBR 07 CIPLBR 01 CIPLBR 12 WTS 1217-7 CIPLBR 02 CIPLBR 39 CIPLBR 20 A90586-11 LBR 9 RARI 35.80 ac S 32.90 a-b S 31.30 a-c S 31.20 a-c S 28.90 a-d S 28.80 a-d S 28.20 a-e S 28.10 a-e S 27.80 a-e S 27.10 a-f S 26.90 a-g S 26.70 b-g MS 26.30 b-g MS 25.70 b-h MS 24.90 b-h MS 24.80 b-h MS 24.40 b-i MS 23.60 c-j MS 22.00 d-k MS 21.90 d-k MS 21.80 d-k MS 21.80 d-k MS 21.30 d-l MS 21.30 d-l MS 21.30 d-l MS 21.30 d-l MS 20.40 d-m MS 20.20 d-m MS 20.00 d-m MS 19.60 e-m MS 19.40 e-m MS 18.30 f-n MS 17.90 g-o MS 16.60 h-p MS i-q 15.60 MS MS i-q 15.50 MS 15.10 j-r MS 14.20 k-r 14.00 k-r MS R 12.40 l-s R 11.80 m-s R 11.70 m-s 9.90 n-s R R 9.90 n-s 9.60 n-s R Onaway Liberator Ach7340_2W MSL175_B MSH067_3 MSM182_1 MSL179_AY MSH360_1 MSL211_3 MSM183_1 Jacqueline Lee MSM414-3Y MSL737_A MSG227_2 MSM171_A MSM224-1 A95053_61 MSK128_A MSL210_A MSF 373_8 MSJ080_1 Snowden MSM140_B MSH094_8 MSM418-5 MSF099 MSH095_4 MSH112_6 MSJ147-1 MSK124_A MSj461_1 A97039_51 MSj1671 MSL159_AY FL1867 Dakota Pearl MSM417-A MSM205_A MSL045_AY MSM409-2Y Pike FL1833 A96895-58 lb 109 R R R R R R R R R R Atlantic BO766_3 MSH228_6 MSK027C 13.90 13.80 9.80 6.50 l-n l-n m-n n R R R R CIPLBR 18 CIPLBR 19 WTS 1217-3 CIPLBR 08 CIPLBR 05 CIPLBR 4 BO767-2 CIPLBR 38 LBR 8 WTS 1212-6 9.00 o-s 8.60 p-s 8.40 p-s 8.20 p-s 8.20 p-s 7.50 p-s 7.20 q-s rs 6.10 4.40 s s 4.30 a Normalized susceptibility score expressed % RARI=[1- Mean ARI treatment / Mean ARI control ] *100; % RARI has a minimum value of zero (no visible symptoms) and maximum value of 100 (Tuber surface is completely blackened). Mean average reflective intensity of n = 30 tubers cut three times at apical, middle and basal region of inoculated potato tubers in light intensity units where LIU 0 = black and 255 = white b Advanced breeding line. c Mean ARI within cultivar/ABL followed by the same letter are not significantly different at P = 0.05 (Tukey multiple comparison test). 110 Cultivar/ ABLc Atlantic J-Lee Pike Torridon FL1879 I157-A J317-1 J319-7 J319-A J453-4Y J456-Y J461-1 inoculated US1 US6 US8 US11 US14 2.5 0.0 2.1 control a 76.7 72.1 ad 68.3 b 49.6 a 7.5 52.9 b 39.6 a 0.0 47.5 a 70.4 63.3 a 68.8 a 37.1 bc 70.4 69.2 a 8.8 51.7 a 12.5 ab 41.3 48.8 66.7 a 60.8 ab 39.2 ab 21.7 ab 67.1 a 48.8 54.2 a 44.2 ab 64.6 68.8 57.1 a 30.4 ab 58.3 b 50.4 a 7.5 59.2 a 25.4 b a 3.3 c 64.2 b b a 1.3 b 20.4 b a 0.0 b b 3.3 a 1.7 b 40.0 ab b a 0.0 d 67.1 ab 13.3 cd cd b b b a 2.1 c 62.9 a 19.2 bc a 0.0 b 34.2 ab 30.8 ab b a 0.0 b 42.1 c 44.2 ab 0.0 c 18.3 bc a 17.5 ab 22.1 ab a a 30.0 ab 0.0 b 19.2 ab 0.0 0.0 3.3 0.0 a 9.6 Table 2 . Survival after planting of potato cultivars and Advanced Breeding Lines inoculated with different genotypes of Phytophthora infestans in 2003. Mean RAUEPCa Genotype of Phytophthora infestans b Non- a RAUEPC, relative area under the percent plant emergence progress curve calculated from 0 - 60 days after planting [full final emergence ( max = 100)]. b Genotype classification according to Goodwin et al. 1995. c Advanced breeding line. d Values followed by the same letter are not significantly different at P = 0.05 for comparisons of mean RAUEPC among different genotypes of P. infestans within each cultivar/ABL (Tukey Multiple Comparison). 111 Table 3: Survival after planting of potato cultivars and Advanced Breeding Lines inoculated with different genotypes of Phytophthora infestans in 2004. Mean RAUEPCa Control Cv/ABLc 86.63 Atlantic 65.92 FL1833 66.10 FL1867 82.20 FL1879 II-152-A 74.95 Jacqueline Lee 78.73 56.33 MN15620 48.36 MN98642 MSJ317-1 68.09 80.16 MSJ461-1 78.07 ND2443 71.21 ND5822C-7 Pike 68.06 83.05 Snowden 81.25 Torridon Megachip 73.86 Phytophthora infestans genotypesb US11 US1 US14 74.31 a-f US6 US8 a-bd 75.29 a-e 82.10 a-c 82.31 a-c 0.00 a-h 84.24 a-c 43.78 d-m 49.55 b-m 77.99 a-d 0.29 20.23 k-o 80.51 a-d 2.97 a-h 67.53 a-g 54.21 a-l 57.44 a-k 83.45 a-c 0.00 88.90 a 62.69 a-i a-c 65.76 a-h 65.15 a-i 38.90 e-n 77.01 a-d 3.73 a-e a-d 76.99 a-d 77.65 a-d 72.38 a-g 76.64 a-d 3.89 a-k 59.72 a-j 65.92 a-h 53.44 a-m 57.97 a-j 2.65 c-m 62.21 a-i 56.73 a-k 29.24 h-o 47.11 c-m 0.00 a-g 70.44 a-g 37.26 f-o 0.29 28.10 i-o 78.87 a-d 77.44 a-d 0.00 a-d 81.06 a-d 76.14 a-e 73.57 a-g 71.66 a-g 1.40 a-d 75.45 a-e 64.62 a-i 66.13 a-h 74.92 a-e 1.27 a-g 73.01 a-g 64.12 a-i a-g 59.06 a-j 16.53 m-o 0.00 71.93 a-g 0.00 2.12 a-c a-d 75.37 a-e 86.39 a-b 80.46 a-d 84.59 a-c 16.71 a-g 79.95 a-d 56.94 a-k 18.22 l-o 76.99 a-d 0.29 82.47 a-c 50.66 b-m 36.68 g-o 22.78 j-o 64.62 a-i o o o n-o o n-o n-o n-o o o o n-o o o n-o l-o o a RAUEPC, relative area under the percent plant emergence progress curve calculated from 0 - 25 days after planting [full final emergence ( max = 100)]. b Genotype classification according to Goodwin et al. 1995. c Advanced breeding line. d Values followed by the same letter are not significantly different at P = 0.05 for comparisons of mean RAUEPC among different genotypes of P. infestans within each cultivar/ABL (Tukey Multiple Comparison). 112 Table 4: Percent plant sand after planting of potato cultivars and Advanced Breeding Lines inoculated with different genotypes of Phytophthora infestans in 2004. Percentage Plant Stand %a Phytophthora infestans genotypes b US11 US14 US6 US1 Cv/ABLc Control Atlantic FL1833 FL1867 FL1879 I152-A Jack lee MN15620 MN98642 MS317-1 MSJ461 ND2443 US8 100.00 a d 87.50 a-d 96.88 a-b 87.50 a-d 96.88 a-b 0.00 k k 81.25 a-e 96.88 a-b 53.13 b-i 56.25 a-i 90.63 a-c 0.00 j-k a-e 81.25 a-e 62.50 a-i 21.88 h-k 93.75 a-b 3.13 78.13 k a-b 100.00 96.88 a 75.00 a-f 71.88 a-g 96.88 a-b 0.00 j-k 87.50 a-d 81.25 a-e 68.75 a-g 46.88 c-j 90.63 a-c 6.25 j-k a-b 87.50 a-d 87.50 a-d 84.38 a-d 87.50 a-d 3.13 96.88 k a-d 78.13 a-e 75.00 a-f 65.63 a-h 78.13 a-e 0.00 84.38 k a-i 84.38 a-d 68.75 a-g 37.50 e-k 62.50 a-i 0.00 62.50 k 93.75 a-b 90.63 a-c 43.75 d-k 31.25 f-k 87.50 a-d 0.00 k a 100.00 100.00 a 90.63 a-c 93.75 a-b 87.50 a-d 0.00 j-k a-b 87.50 a-d 75.00 a-f 87.50 a-d 81.25 a-e 3.13 93.75 k a-d 78.13 a-e 71.88 a-g 71.88 a-g 84.38 a-d 0.00 87.50 k 75.00 a-f 71.88 a-g 18.75 i-k k 87.50 a-d 0.00 a-b 93.75 a-b 56.25 a-i 43.75 d-k 28.13 g-k 0.00 93.75 k a-c 87.50 a-d 93.75 a-b 93.75 a-b 96.88 ab 21.88 h-k 90.63 87.50 a-d 93.75 a-b 65.63 a-h 21.88 h-k 90.63 abc 0.00 k Snowden Torridon W1201 ND5822C-7 Pike 0.00 a Percentage plant stand calculated from 0 – 60 days after planting [full final plant stand ( max = 100)]. b Genotype classification according to Goodwin et al. 1995. c Advanced breeding line. d Values followed by the same letter are not significantly different at P = 0.05 for comparisons of mean percent plant stand among different genotypes of P. infestans within each cultivar/ABL (Tukey Multiple Comparison). 113 Table 5. Susceptibility of tubers of potato cultivars and advanced breeding lines to different genotypes of Phytophthora infestans in 2003; susceptibility is expressed in terms of relative average reflective intensity (RARI%). CV/ABL a US-1 Phytophthora infestans genotypes US-6 US-11 US-8 US-14 Atlantic J-Lee Pike Torridon FL1879 I157-A J317-1 J319-7 J319-A J453-4Y J456-Y J461-1 RARI b 0.00 41.59 42.25 0.00 13.21 42.45 29.25 0.00 13.15 12.15 14.08 41.31 0.00 12.62 12.21 0.00 0.00 12.26 12.74 11.74 12.68 0.00 0.47 0.47 a c c c a b d c a b b c d a b b a a b b b b a a a 42.45 40.65 42.72 41.98 41.04 41.04 41.51 42.25 41.78 29.91 11.27 27.23 c c c c d d d c d c b c 0.00 12.62 41.31 13.21 0.00 28.30 28.77 0.00 28.64 0.93 11.74 13.62 a b c b a c c a c a b b 12.74 41.59 42.25 41.04 28.30 41.51 41.51 41.31 42.25 29.44 12.68 42.25 b c c c c d d c d c b-c d a Cultivar /Advanced breeding line. b Normalized susceptibility score expressed % RARI=[1- Mean ARI treatment / Mean ARI control ] *100; % RARI has a minimum value of zero (no visible symptoms) and maximum value of 100 (Tuber surface is completely blackened). Mean average reflective intensity of n = 30 tubers cut three times at apical, middle and basal region of inoculated potato tubers in light intensity units where LIU 0 = black and 255 = white c Mean RARI within cultivar/ABL followed by the same letter are not significantly different at P = 0.05 (Tukey multiple comparison test). 114 Table 6. Susceptibility of tubers of potato cultivars and advanced breeding lines to different genotypes of Phytophthora infestans; susceptibility is expressed in terms of relative average reflective intensity (RARI%). Phytophthora infestans genotypes Pi 98_1 (US-14) Pi 96_2 (US-6) Pi02007 (US-8) Pi 96_1 (US-11) Pi 95_3 (US-1) RARI b r-s g-o k-s j-s f-n g-q r-s r-s r-s j-s g-p h-s j-s s c 0.00 h-s 5.92 o-s 1.29 i-s 4.71 e-m 8.02 f-n 7.74 j-s 3.86 k-s 3.27 2.38 m-s 6.24 h-r 3.90 j-s 1.96 m-s 2.64 l-s 0.37 7.44 3.35 4.46 7.78 6.93 0.16 0.67 0.60 4.48 7.09 6.08 4.70 Jacqueline Lee CV/ABL a Atlantic I-152 A J461-1 MN 98642 Mn15620 MS317-1 ND 2443 ND5822C7 Pike Snowden Torridon Megachip r-s 0.56 10.79 e-i 2.50 m-s q-s 0.77 1.15 p-s p-s 1.05 j-s 3.90 0.17 r-s o-s 1.38 r-s 0.55 5.84 h-s p-s 1.07 1.23 p-s 0.19 5.82 2.66 1.71 8.73 8.70 2.78 0.93 0.98 14.08 5.69 0.36 4.90 r-s h-s l-s n-s e-l e-l l-s q-s p-s c-e h-s r-s i-s 2.48 m-s j-s 4.27 28.33 a e-k 9.08 21.42 b e-i 11.10 e-j 9.60 17.30 b-d d-g 12.55 d-g 12.77 19.01 b-c c-f 13.73 11.77 d-h a Cultivar /Advanced breeding line. b Normalized susceptibility score expressed % RARI = [1- Mean ARI treatment / Mean ARI control] *100; % RARI has a minimum value of zero (no visible symptoms) and maximum value of 100 (Tuber surface is completely blackened). Mean average reflective intensity of n = 8 tubers cut three times at apical, middle and basal region of inoculated potato tubers in light intensity units where LIU 0 = black and 255 = white c Mean RARI within cultivar/ABL followed by the same letter are not significantly different at P = 0.05 (Tukey multiple comparison test). 115 Figure 1. Scanned images of blighted tubers with RARI values. Higher values indicate more darkening due to greater susceptibility to Phytophthora infestans. 116 References Kirk, W.W., Felcher, K.J., Douches, D.S., Coombs. J., Stein, J.M., Baker, K.M. and Hammerschmidt, R. (2001a). Effect of host plant resistance and reduced rates and frequencies of fungicide application to control potato late blight. Plant Disease 85(10): 1113-1118. Kirk, W.W., K. J. Felcher, D. S. Douches, B. A. Niemira and R. Hammerschmidt. (2001b) Susceptibility of potato (Solanum tuberosum l.) foliage and tubers to the US8 genotype of Phytophthora infestans, Amer. J. Potato Res.78:319-322. Kirk, W.W., B.A. Niemira and J.M. Stein. (2001c). Influence of storage 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. Stevenson, W.R., Management of early blight and late blight. In R.C. Rowe ed. Potato Health Management, APS Press, St. Paul, MN, (1993) pp. 141-148. 117 Funding: MPIC, MSU and Industry Potato late blight caused by Phytophthora infestans (Mont. de Bary) is the most Evaluation of fungicide programs for potato late blight control, 2004. W. W. Kirk, R. L Schafer, D. Berry, P. Wharton and P. Tumbalam. Department of Plant Pathology, Michigan State University, East Lansing, MI 48824 Introduction important foliar and tuber disease of potato, both in the field and in storage. Late blight causes rapid defoliation of plants in the field and can infect potato tubers when spores are washed into the soil. Potato late blight management strategies have changed considerably following the migration of metalaxyl resistant isolates of P. infestans from Mexico to North America and necessitate utilization of cultural control measures and modification of the previous chemical control practices. The new strategies rely on reducing fungicide inputs, and this can be achieved by introducing new fungicides or integrating new fungicides with specific activity against late blight and lower amount of active ingredient. The lack of availability of varieties with host resistance necessitates cultural control methods and crop protection strategies that rely primarily on protectant foliar fungicide applications. Fully-protectant foliar fungicide programs usually begin before the predicted onset of potato late blight, consist of fungicide applications that continue throughout the growing season at regular intervals, and may be initiated by weather-based potato late blight prediction models. Full protectant programs potentially require unnecessary input in seasons that are non-conducive to potato late blight development, and may have the most environmental impact; however they have the least failure risk. Risk of failure may occur for several reasons; presence of late blight contaminated seed; highly conducive environmental conditions that enhance sporulation and infection; fungicide misapplication or application at sub-effective rates, therefore, many growers initiate fungicide application programs early in the season and continue until vines are fully desiccated at frequency of 5 to 7 day intervals with the maximum labeled rates of protectant fungicides to ensure late blight free produce. The Muck Soils Research Farm, Bath, Michigan is the designated location for potato late blight research at Michigan State University. This location has been an ideal testing site for foliar reaction to P. infestans because: 1) of its isolation from potato production regions, 2) a humid microclimate that is conducive to the development and spread of late blight disease, and 3) consistent P. infestans infection levels over years. New fungicide products require evaluation and the objective of this program is to test the efficacy of fungicides under extremely conducive conditions in the presence of aggressive strains of the pathogen P. infestans. Method and materials Potatoes [cut seed, treated with Maxim MZ 0.5D (0.5 lb/cwt)] were planted at the Michigan State University Muck Soils Experimental Station, Bath, MI on 28 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 30 Jul. All fungicides in this trial were applied on a 7-day interval from 21 Jul to 8 Sep (8 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. The pivot trial was 118 chemigated on a 7-day interval from 21 Jul to 27 Aug (7 applications) with a Valley Irrigation overhead single span pivot delivering 5,000 gal water/A per application (see Table 4). Weeds were controlled by hilling and with Dual 8E (2 pt/A on 28 Jun), Basagran (2 pt/A on 28 Jun and 25 Jul) and Poast (1.5 pt/A on 25 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 28 Jun), Sevin 80S (1.25 lb/A on 11 and 25 Jul), Thiodan 3EC (2.33 pt/A on 1 and 21 Aug) and Pounce 3.2EC (8 oz/A on 25 Jul). Plots were rated visually for percentage foliar area affected by late blight on 30 Jul; 11, 17, 24 Aug and 2 and 13 Sep [5 days after final application (DAFA), 45 days after inoculation (DAI)] 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, 30 Jul to 13 Sep, a period of 45 days. Vines were killed with Reglone 2EC (1 pt/A on 13 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 88.2 and 67.2 (Jun), 87.5 and 67.7 (Jul), 88.1 and 67.7 (Aug) and 85.3 and 66.0 (Sep). Maximum and minimum soil temperature (oF) were 74.5 and 69.8 (Jun), 77.0 and 71.9 (Jul), 78.0 and 71.4 (Aug) and 75.9 and 70.2 (Sep). Maximum and minimum soil moisture (% of field capacity) was 98.5 and 95.8 (Jun, severe flooding); 98.1 and 63.3 (Jul), 85.4 and 71.4 (Aug) and 76.8 and 79.8 (Sep). Precipitation was 4.04” (Jun), 3.68" (Jul), 1.83" (Aug) and 0.93" (Sep). The total number of late blight disease severity values (DSV) over the inoculation period was 116 and 44 (using 80% and 90% ambient %RH as bases for DSV accumulation), respectively (Figure 1). Plots were irrigated to supplement precipitation to about 0.5"/A/4 day period with overhead sprinkle irrigation. Results Block 1 Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 100% foliar infection by 13 Sep. Taking 34 DAI as a key reference point, all fungicide programs reduced the foliar late blight significantly compared to the untreated control except programs 16 and 17. Programs with 0.4 to 2.1% foliar late were not significantly different. Taking 45 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 except programs 16 and 17. Programs with 1.8 - 11.8% foliar late blight; and those with 11.8 - 25.0% foliar late blight were not significantly different. All fungicide programs significantly reduced the average amount of foliar late blight over the season (RAUDPC, 0 to 45 DAI) compared to the untreated control except programs 16 and 17. Application programs with RAUDPC values between 0.35 and 4.62 were not significantly different. All treatments had significantly greater marketable yield in comparison to the non-treated control except programs 16 and 17. Programs with marketable yield from 304 - 409 cwt/A, from 269 - 373 cwt/A, and from 186 - 291 cwt/A were not significantly different. All treatments had significantly greater total yield in comparison to the non-treated control except programs 16 and 17. Treatments with total yield between 351 and 467 cwt/A; 315 and 428 cwt/A; between 242 and 359 cwt/A; and between 227 and 339 cwt/A were not significantly different. Phytotoxicity was not noted in any of the treatments. 119 Table 1. Efficacy of fungicides applied by ground equipment against foliar late blight (Block 1); MSU 2004. RAUDPCx Max (100) 0 - 45 DAI 4.62 b 0.47 b 0.50 b 0.46 b Yield (cwt/A) US1 Total 345 ab 373 ab 322 ab 306 ab 401 ab 428 ab 383 ab 371 ab 3.3 c 0.56 b 304 ab 382 ab 3.5 c 0.58 b 291 bc 353 abc 2.8 c 0.54 b 298 b 359 abc 2.0 c 0.39 b 333 ab 396 ab 3.0 c 0.59 b 281 bc 338 bcd 1.8 c 0.35 b 298 b 374 ab 3.3 c 0.51 b 304 ab 352 abc Foliar late blight (%) 34 DAIz 45 DAI 5 DAFAy 25.0 b 1.8 c 2.8 c 2.5 c Treatment and rate/acre 1 Dithane RS 75DF 1.5 lb (A,B,C,D,E,F,G,Hw).................................... 6.3 bv 2 Gavel 75DF 2.0lb (A,B,C,D,E,F,G,H)................................................ 0.7 b 3 Echo ZN 2.13 pt (A,B,C,D,E,F,G,H).................................................. 0.5 b 4 Echo 825 1.38 pt (A,B,C,D,E,F,G,H,I) .............................................. 0.5 b 5 Echo ZN 2.13 pt + Amistar 80WDG 0.13 lb (A,C); Echo ZN 2.13 pt (B,D,E,F,G,H)......................................................... 0.6 b 6 Bravo WS 6SC 1.5 pt (A,B,C,E,F); Omega 5SC 0.5 pt (D,G); Ranman 40SC 0.17 pt + Silwet 6SC 0.1 pt (H)................................. 0.5 b 7 Bravo WS 6SC 1.5 pt (A,B,C,D,F,H); Ranman 40SC 0.17 pt + Silwet 6SC 0.1 pt (E,G).............................. 0.7 b 8 Bravo WS 6SC 1.5 pt (A,B,C,G); Omega 5SC 0.5 pt (D,H); Ranman 40SC 0.17 pt + Silwet 6SC 0.1 pt (E,G).............................. 0.5 b 9 Bravo WS 6SC 1.5 pt (A,B); Ranman 40SC 0.17 pt + Silwet 6SC 0.1 pt (C,E,G); Omega 5SC 0.5 pt (D,F,H)................................................................. 0.8 b 10 Bravo WS 6SC 1.5 pt + Amistar 80WDG 0.13 lb (A,C); Bravo WS 6SC 1.5 pt (B,D,E,F,G,H)................................................. 0.4 b 11 Equus 6SC 1.5 pt + Amistar 80WDG 0.13 lb (A,C); Equus 6SC 1.5 pt (B,D,E,F,G,H)........................................................ 0.4 b 12 Equus ZN 2.13 pt + Amistar 80WDG 0.13 lb (A,C); 4.5 c 92.5 a 0.82 b 24.6 a 291 bc 104 e 353 abc 171 e Equus ZN 2.13 pt (B,D,E,F,G,H)........................................................ 0.8 b 13 Untreated............................................................................................ 56.3 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. w Application dates: A= 21 Jul; B= 28 Jul; C= 4 Aug; D= 11 Aug; E= 18 Aug; F= 25 Aug; G= 1 Sep; H= 8 Sep. v Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Block 2 Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 100% foliar infection by 13 Sep. Taking 34 DAI as a key reference point, all fungicide programs reduced the foliar late blight significantly compared to the untreated control. Programs with 0.4 to 8.0% foliar late were not significantly different. Taking 45 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. Programs with 1.5 - 8.8% foliar late blight; 2.5- 12.8% foliar late blight; 5.3- 15.0% foliar late blight; 7.8- 17.3% foliar late blight; 12.8 - 22.5% foliar late blight; 17.3 - 27.5% foliar late blight; and 22.5 - 28.8% foliar late blight were not significantly different. All fungicide programs significantly reduced the average amount of foliar late blight over the season (RAUDPC, 0 to 45 DAI) compared to the untreated control. Application programs with RAUDPC values between 0.30 and 4.07; and 0.95 and 5.43 were not significantly different. Most treatments had significantly greater marketable yield in comparison to the non-treated control except programs with less than 293 cwt/A. Programs with marketable yield from 259 - 374 cwt/A were not significantly different. All treatments had significantly greater total yield in comparison to the non-treated control except programs with less than 361 cwt/A. Treatments with total yield between 296 and 421 cwt/A were not significantly different. Phytotoxicity was not noted in any of the treatments. 120 Table 2. Efficacy of fungicides applied by ground equipment against foliar late blight (Block 2); MSU 2004. Treatment and rate/acre 1 Reason 500SC 0.26 pt + Dithane RS 75DG 1.0 lb + Bond 500SC 0.5 pt (A,C,E,Gw) Dithane RS 75DG 2.0 lb (B,D,F,H).................................................... 2.8 bv 27.5 bc 4.04 bc 259 ab 313 ab Foliar late blight (%) 34 DAIz 45 DAI 5 DAFAy RAUDPCx Max = 100 0 - 45 DAI Yield (cwt/A) US1 Total 2 Reason 500SC 0.26 pt + Echo 720SC 1.0 pt + Bond 500SC 0.5 pt (A,C,E,G) Dithane RS 75DG 2.0 lb (B,D,F,H).................................................... 2.4 b 3 Bravo ZN 6SC 2.13 pt (A,C,E,G,H); Endura 6WDG 0.16 lb + Bravo WS 6SC 1.0 pt (B,D)........................ 0.8 b 4 Bravo ZN 6SC 2.13 pt (A,C,E,G,H); Headline 2SC 0.38 pt + Bravo WS 6SC 1.0 pt (B,D)......................... 0.6 b 5 Bravo ZN 6SC 2.13 pt (A,C,E,G,H); Headline 2SC 0.38 pt + Bravo WS 6SC 1.0 pt (B); Endura 6WDG 0.16 lb + Bravo WS 6SC 1.0 pt (D)........................... 0.6 b 6 Bravo ZN 6SC 2.13 pt (A,C,E,G,H); Endura 6WDG 0.16 lb + Bravo WS 6SC 1.0 pt (B); Headline 2SC 0.38 pt + Bravo WS 6SC 1.0 pt (D)............................. 0.5 b 7 Bravo ZN 6SC 2.13 pt (A,C,G,H); Endura 6WDG 0.16 lb + Bravo WS 6SC 1.0 pt (B,E); Headline 2SC 0.38 pt + Bravo WS 6SC 1.0 pt (D)............................. 0.4 b 8 Bravo ZN 6SC 2.13 pt (A,C,G,H); Headline 2SC 0.38 pt + Bravo WS 6SC 1.0 pt (B,E); Endura 6WDG 0.16 lb + Bravo WS 6SC 1.0 pt (D)........................... 0.4 b 9 Bravo ZN 6SC 2.13 pt (A,C,F,G,H); Endura 6WDG 0.16 lb + Bravo WS 6SC 1.0 pt (B,D); Headline 2SC 0.38 pt + Bravo WS 6SC 1.0 pt (E)............................. 0.7 b 10 Bravo ZN 6SC 2.13 pt (A,C,F,G,H); Headline 2SC 0.38 pt + Bravo WS 6SC 1.0 pt (B,D); Endura 6WDG 0.16 lb + Bravo WS 6SC 1.0 pt (E)............................ 0.5 b 11 Bravo Ultrex 82.5 WDG 1.08 lb (A,B,C,D,E,F,G,H)......................... 0.8 b 12 Bravo Ultrex 82.5 WDG 0.74 lb (A,B,C,D,E,F,G,H)......................... 4.5 b 13 Dithane RS 75WDG 2.0 lb (A,B,C,D,E,F,G,H)................................. 3.0 b 14 Amistar 80WDG 0.13 lb + Bravo WS 6SC 1.5 pt (A,C); Bravo WS 6SC 1.5 pt (B,D,E,G); Sonata (QRD 286) 4.0 pt + Biotune (QRD 602) 0.5 pt (F, H)............ 8.0 b 15 Amistar 80WDG 0.13 lb + Bravo WS 6SC 1.5 pt (A,C); 15.0 def 2.44 bc 310 a 359 ab 3.0 gh 0.59 c 266 ab 305 ab 5.3 fgh 0.83 c 343 a 397 a 2.8 gh 0.51 c 322 a 368 a 1.8 h 0.37 c 351 a 394 a 2.5 gh 0.40 c 316 a 360 ab 1.5 h 0.30 c 350 a 401 a 2.5 gh 0.50 c 374 a 421 a 0.54 c 3.3 gh 3.5 gh 0.65 c 17.3 cde 3.16 bc 27.5 bc 4.07 bc 334 a 261 ab 307 a 321 a 374 a 296 ab 361 ab 368 a 28.8 b 5.43 b 293 ab 348 ab 8.8 efgh 1.63 bc 3.79 bc 27.0 bc 100 a 31.5 a Bravo WS 6SC 1.5 pt (B,D,E,G); Sonata (QRD 286) 4.0 pt + Kocide 2000 6DF 2.0 lb + Biotune (QRD 602) 0.5 pt (F,H)......................................................... 2.1 b 16 Penncozeb 75DF 2.0 lb (A,B,C,D,E,F,G,H)....................................... 2.0 b 17 Untreated............................................................................................ 71.3 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. w Application dates: A= 21 Jul; B= 28 Jul; C= 4 Aug; D= 11 Aug; E= 18 Aug; F= 25 Aug; G= 1 Sep; H= 8 Sep. v Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Block 3 (Ground and Chemigation comparison of Tanos applciation) In both the pivot and ground application trials, ate blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 100% foliar infection by 13 Sep. In the ground application trial, taking 34 DAI as a key reference point, all fungicide programs reduced the foliar late blight significantly compared to the untreated control. Programs with less than 0.9 to 4.5% foliar late were not significantly different. Taking 45 DAI as a key reference point, there 312 a 317 a 170 b 368 a 370 a 234 b 121 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. Programs with 2.5 - 7.0% foliar late blight; and those with 27.5% (program 5) and those with 40.0 - 50.0% foliar late blight were not significantly different. All fungicide programs significantly reduced the average amount of foliar late blight over the season (RAUDPC, 0 to 45 DAI) compared to the untreated control. Application programs with RAUDPC values between 0.53 to 1.09; those with RAUDPC values 1.09 to 3.92; those with RAUDPC values 3.92 to 6.52; and those with RAUDPC values 6.32 to 7.26 were not significantly different. All treatments had significantly greater marketable yield in comparison to the non-treated control but there was no difference among treatments. All treatments had significantly greater total yield in comparison to the non-treated control but there was difference among treatments with total yield between 264 and 312 cwt/A and between 272 and 319 cwt/A. In the pivot trial, taking 25 DAI as a key reference point, all fungicide programs reduced the foliar late blight significantly compared to the untreated control. Taking 34 DAI as a key reference point, there was close to 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 with 1.3 to 2.7% foliar late blight; and those with 2.7 to 6.5% foliar late blight were not significantly different. All fungicide programs significantly reduced the average amount of foliar late blight over the season (RAUDPC, 0 to 45 DAI) compared to the untreated control. There were no significant differences in RAUDPC among application programs. All treatments had significantly greater marketable and total yield in comparison to the non-treated control but there was no difference among treatments. Phytotoxicity was not noted in any of the treatments. 122 Treatment and rate/acre 1 Tanos 50WDG 0.25 lb + Manzate 75DF 1.5 lb (A,C,E,G)w Manzate 75DF 2.0 lb (B,D,F,H)................................................... 2 Tanos 50WDG 0.39 lb + Manzate 75DF 1.5 lb (A,C,E,G) Manzate 75DF 2.0 lb (B,D,F,H)................................................... 3 Tanos 50WDG 0.5 lb + Manzate 75DF 1.5 lb (A,C,E,G) Manzate 75DF 2.0 lb (B,D,F,H)................................................... 4 Tanos 50WDG 0.5 lb + Manzate 75DF 1.5 lb (A,C,E,G) Bravo WS 6SC 1.5 pt (B,D,F,H)................................................. 5 Tanos 50WDG 0.39 lb + Super Tin 80WP 0.16 lb (A,C,E,G) Manzate 75DF 2.0 lb + Super Tin 80WP 0.16 lb (B,D,F,H)........ 6 Manzate 75DF 2.0 lb (B,D,F,H)................................................... 7 Amistar 80WDG 0.13 lb (A,C,E,G) Foliar late blight (%) 34 DAIz 45 DAI 5 DAFAy RAUDPCx Max = 100 0 - 45 DAI US1 Yield (cwt/A) Total 4.3 ax 42.5 b 6.32 bc 261 a 307 ab 3.3 a 3.3 a 0.9 a 2.1 a 4.5 a 40.0 b 5.74 bc 269 a 312 ab 46.3 b 6.52 bc 224 a 274 ab 2.5 d 0.53 e 252 a 298 ab 27.5 c 50.0 b 3.92 cd 7.26 b 269 a 226 a 319 a 264 b Bravo WS 6SC 1.5 lb (B,D,F,H).................................................. 0.9 a 8 Untreated...................................................................................... 82.5 b 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. w Application dates: A= 21 Jul; B= 28 Jul; C= 4 Aug; D= 11 Aug; E= 18 Aug; F= 25 Aug; G= 1 Sep; H= 8 Sep. v Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Pivot application 1.09 de 33.37 a 7.0 d 100.0 a 230 a 87 b 272 ab 136 c Table 3. Efficacy and comparison of fungicides applied by ground and chemigation equipment against foliar late blight (Block 3); MSU 2004. Ground application Treatment and rate/acre 1 Tanos 50WDG 0.5 lb + Manzate 75DF 1.5 lb (A,C,E,G)x Manzate 75DF 2.0 lb (B,D,F)....................................................... 2 Tanos 50WDG 0.5 lb + Manzate 75DF 1.5 lb (A,C,E,G) Bravo WS 6SC 1.5 pt (B,D,F)..................................................... 3 Amistar 80WDG 0.13 lb (A,C,E,G) Foliar late blight (%) 25 DAIz 34 DAI RAUDPCy Max = 100 0 - 34 DAI US1 Yield (cwt/A) Total 2.1 bw 6.5 b 1.36 b 256 a 390 a 0.9 b 2.7 bc 0.57 b 247 a 399 a 267 a 139 b 1.3 c 94.4 a 408 a 303 b 0.30 b 23.68 a Bravo WS 6SC 1.5 lb (B,D,F)...................................................... 0.6 b 4 Untreated...................................................................................... 46.5 a z Days after inoculation with Phytophthora infestans, US8, A2. y RAUDPC, relative area under the disease progress curve calculated from day of inoculation to last evaluation of late blight. x Application dates: A= 15 Jul; B= 22 Jul; C= 19 Jul; D= 5 Aug; E= 12 Aug; F= 19 Aug; G= 27 Aug. w Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Block 4 Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 100% foliar infection by 13 Sep. Taking 34 DAI as a key reference point, all fungicide programs reduced the foliar late blight significantly compared to the untreated control. Programs with 0.7 to 1.6% foliar late were not significantly different. Taking 45 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. Programs with 1.0 - 4.5% foliar late blight were not significantly different. All fungicide programs significantly reduced the average amount of foliar late blight over the season (RAUDPC, 0 to 45 DAI) compared to the untreated control. Application programs with RAUDPC values between 0.34 123 and 0.89 were not significantly different. All treatments had significantly greater marketable and total yield in comparison to the non-treated control. Programs with marketable yield from 223 - 274 cwt/A; and from 242 - 307 cwt/A were not significantly different. Treatments with total yield between 297 and 327 cwt/A were not significantly different. Phytotoxicity was not noted in any of the treatments. Table 4. Efficacy of fungicides applied by ground equipment against foliar late blight (Block 4); MSU 2004. Foliar late blight (%) 34 DAIz 45 DAI 5 DAFAy RAUDPCx Max = 100 0 - 45 DAI Yield (cwt/A) US1 Total 297 b 293 b 364 b 310 b 301 b 327 b 148 a 0.3 b 25.9a 1.0 b 100.0 a 274 bc 75 a 0.8 b 0.9 b 0.6 b 0.9 b 0.7 b 3.0 b 4.5 b 2.1 b 2.9 b 3.0 b 245 bc 223 b 307 c 268 bc 242 bc Treatment and rate/acre 1 Bravo WS 6SC 1.5 pt (A-Hw)............................................................. 1.4 bv 2 Bravo WS 6SC 0.75 pt (A-H)............................................................. 1.1 b 3 Acrobat 50 WP 0.4 lb + Dithane RS 75WDG 2.0 lb (A-H)............... 0.8 b 4 BAS 550 SC 0.38 pt + Dithane RS 75WDG 2.0 lb (A-H).................. 1.6 b 5 BAS 550 SC 0.38 pt + Parafnic Oil 75SC 0.5 pt (A-H)...................... 1.0 b BAS 550 SC 0.38 pt + Parafnic Oil 75SC 0.5 pt + 6 Dithane RS 75WDG 2.0 lb (A-H)....................................................... 0.7 b 7 Untreated............................................................................................ 47.5 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. w Application dates: A= 21 Jul; B= 28 Jul; C= 4 Aug; D= 11 Aug; E= 18 Aug; F= 25 Aug; G= 1 Sep; H= 8 Sep. v Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Block 5 Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 100% foliar infection by 13 Sep. Taking 34 DAI as a key reference point, all fungicide programs reduced the foliar late blight significantly compared to the untreated control. Programs with 0.58 to 2.80 % foliar late were not significantly different. Taking 45 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. Programs with 1.75 – 5.5 % foliar late blight were not significantly different. All fungicide programs significantly reduced the average amount of foliar late blight over the season (RAUDPC, 0 to 45 DAI) compared to the untreated control. Application programs with RAUDPC values between 0.40 and 5.3 were not significantly different. All treatments had significantly greater marketable yield in comparison to the non-treated control except program 3. Programs with marketable yield from 193 - 276 cwt/A were not significantly different. All treatments had significantly greater total yield in comparison to the non-treated control except program 3. Treatments with total yield between 239 and 332 cwt/A were not significantly different. Although treatments 1 and 2 had zero incidence of tubers with symptoms or signs of late blight there was no significant difference among any treatments or the non-treated control. Phytotoxicity was not noted in any of the treatments. 124 Table 5. Efficacy of fungicides applied by ground equipment against foliar late blight (Block 5); MSU 2004. Foliar late blight (%) 45 DAI 5DAFAy 34 DAIz RAUDPCx Max = 100 0 - 45 DAI Yield (cwt/A) US1 Total Tuber LBw Treatment and rate of application/A 1 Calguard 1.0 pt + Rezist 2.0 pt + Sugar Mover 1.0 pt + Bravo WS 6SC 1.5 pt (A,Bv) Calguard 1.0 pt + Rezist 2.0 pt + Sugar Mover 1.0 pt + Previcur 1.2 pt (C,D,E,F) 2 Calguard 1.0 pt + Sugar Mover 1.0 pt + Bravo WS 6SC 1.5 pt (A,B) Calguard 1.0 pt + Sugar Mover 1.0 pt + Previcur 1.2 pt (C,D,E,F) 3 Calguard 1.0 pt + Rezist 2.0 pt + 0.85 bu 1.75 c 0.4 b 256 2.80 b 5.5 c 1.4 b 233 a a LSD (p = 0.05)t Sugar Mover 1.0 pt (A,B,C,D,E,F) 2.75 4 Bravo WS 6SC 1.5 pt (A,B,C,D,E,F) 0.58 5 Untreated.................................................................... 65.0 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. w Incidence of tubers with symptoms or signs of potato late blight 82 days after harvest. v Application dates: A= 4 Aug; B= 11 Aug; C= 18 Aug; D= 25 Aug; E= 1 Sep; F= 8 Sep. u Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). t Least significant difference at p = 0.05 if no significant difference amongst mean values for any measurement. 193 276 84 37.5 2.5 100 ab a b 5.3 0.4 28.0 b b a b b a b c a 315 a 0.0 284 239 332 145 a ab a b 0.0 4.4 9.0 7.6 18.53 125 V S D d e t l a u m u c c A 140 120 100 80 60 40 20 0 Accumulated DSV from planting to desiccation 28 Jun - 15 Sep 2004. Late blight first noted in non-treated plots 12 DAI. Inoculation 32 days after planting In canopy monitor Monitor 45 cm above canopy 0 20 40 80 Days after planting (28 June) 60 100 120 Figure 1. Accumualted late blight disease sevetiy values from planting to desiccation. 126 Michigan Potato Industry Commission 2004 Nematology Annual Report George W. Bird, Professor Department of Entomology, Michigan State University The 2004 Michigan State University Potato Nematode Research Program consisted of the following three projects: 1. Evaluation of potato lines and varieties for tolerance or resistance to the Potato Early-Die Disease Complex (Federal Project funded). 2. Impact of alternative tillage practices on tuber yield and root-lesion nematodes associated with potato production (MPIC funded). 3. Identification of the impacts of an alternate short-tem potato/vegetable cropping system trial and a soil quality restoration trial on soil quality as measured by nematode community structure analysis (MPIC funded). A history of the Potato Early-Die Disease Complex Research in Michigan is included as an introduction to the 2004 Annual Report. The section entitled, Evaluation of Potato Varieties and Breeding Lines for Tolerance to Early-Die, was published in the February 2005 issue of the Michigan Potato News Line. History of the Potato Early-Die Disease Complex Research in Michigan When I arrived at Michigan State University in August of 1973, Michigan potato growers were just beginning to recognize the significance of potato early-die. A few farms were experimenting with soil fumigants such as D-D, Telone and Vorlex for control of this disease complex. The objective of this article is to: 1) review what has happened in MI during the last three decades in relation to potato early-die, 2) briefly describe my views about future research needs and 3) outline the current management recommendations. Nature and Extent of the Problem.- The potato early-die disease complex is caused by an interaction between the root-lesion nematode (Pratylenchus penetrans) and a fungus known as Verticillium dahliae. It is usually most severe in coarse textured soils (sands and sandy loams). A 1975 survey funded by MIPC indicated that the root-lesion nematode was present in 63.6% of MI potato fields. In a similar survey in 1982, this nematode was recovered from 93.8% of the acreage sampled. In 2004, the potato early- die disease complex remains as a serious challenge to about 50% of MI potato acreage. MI tuber yields in the presence of potato early-die can be as low as 150 cwt/acre, whereas they can exceed 500 cwt/acre in the absence of this problem. The problem is most severe in sites that are degraded or of low soil quality. The overall concept of soil quality is discussed in this article. 127 action thresholds In the late 1980s and early 1990s, our nematology laboratory began a comprehensive research program to learn more about the nature of the underground growth and development of the potato plant. Much to my surprise, the situation was more complex than expected. The below ground part of the potato plant consists of eight different parts (seed piece, basal roots, below ground stems, nodal roots, stolons, stolon roots, tubers and tuber roots). All of these parts have different functions and develop at different times. We learned that when root-lesion nematodes are present, basal root growth is inhibited within the first three weeks after planting, leading to low tuber yields at harvest. It was then discovered that root-lesion nematodes can directly invade stolon tissue, stolon roots and tuber roots, leading to further reductions in potato yield potential and tuber quality. Thresholds-Predictive Models.- Research designed to determine root-lesion nematode and Verticillium population densities required for a potato early-die problem and management was funded by MPIC in the late 1970s. This work resulted in the potato early-die currently used by MSU Diagnostic Services, www.cips.msu.edu/diagnostsics. It is strongly encouraged that all MI potato land that is not making its yield goals or is known to have a high risk to potato early-die be periodically sampled for both the root-lesion nematode and V. dahliae. Nematicide Use and Research.- Research on fumigant and non-fumigant nematicides was conducted at MSU from 1974 through 1999. This work consisted of evaluation of fumigant nematicides such as Telone, Telone II, Vorlex, Vidden-D, Soil-Brom, Nemagon and Fumazone; non-fumigant nematicides such as Temik, Mocap, Vydate, Mocap and Furadan; and chemigants such as Vapam and Busan 1020. Many experimental compounds were also evaluated. In recent years, the MSU Bird Nematology Laboratory has also evaluated a large number of bionematicides. Shortly after MI potato growers began to use D-D, Telone or Vorlex for nematode control, the non-fumigant nematicide-insecticide, Temik 15G was registered for use in potato production. I previously had five years of experience with this product as a cotton nematologist at the University of Georgia. Temik was used on about 50% of the MI potato acreage the first year it was available and 75% the second year. The third year, Temik usage was reduced to about 50% of the acreage, where it remained as long as this product was available in MI for use in potato production. Temik was easy to apply, did an excellent job of controlling root-lesion nematodes, was less expensive than most other nematicides and also provided control of some economically important potato insect pests. Chemigation became popular in MI potato production in the mid-1980s. Initially, chemigants such as Vapam or Busan 1020 were applied through center-pivot irrigation systems, resulting in outstanding root-lesion nematode control and extremely high tuber yields. Later, systems were developed for application through travelers and ground- driven equipment. Chemigation remains an important component of MI potato production in 2004. 128 When Temik, an organocarbamate, was banned for use in Michigan, most potato growers using this product switched to Mocap, an organophosphate. Although Mocap is an excellent product for root-lesion nematode control, it does not move very well in soil water like Temik. Mocap must be thoroughly incorporated into the soil. The MI potato production system did not have a very good way to incorporate this product and results were often less satisfactory than that previously experienced through the use of Temik or a chemigant. In recent years there has been a significant increase in the use of Vydate, an organocarbamate, for root-lesion nematode control in MI potato production. The MPIC pesticide use survey is excellent and provides information that is currently not available for most other MI commodities. I strongly encourage the industry to continue this initiative. Resistant Varieties.- Research on the severity of potato early-die associated with various potato varieties was conducted with relatively little success between 1975 and 1997. In 1998, the Bird-Nematology Laboratory at MSU began to evaluate selected varieties and lines associated with Dr. Douches potato breeding program. The results of this USDA-funded initiative is described in detail in the 2003 Michigan Potato Research Report. A number of lines with potato early-die tolerance have been identified, and one line has exhibited possible resistance. If I have one regret in relation to my potato-early die research program, it would be that the resistant variety program was not started much earlier. The availability of numerous excellent soybean cyst nematode resistant soybean varieties has had a major positive impact on the MI soybean industry. During the past year I have started a new sugar beet cyst nematode resistant variety program that looks promising. Biological Control.- There are two types of biological control in relation to nematodes that relate to potato production. The first uses living organisms to control plant-parasitic nematodes, such as the root-lesion nematode. Many potential biological control agents have been evaluated during the past decade for management of potato dearly-die in MI. Most of the candidates have worked well under laboratory conditions. None of them, however, have been successful in our trials under field conditions. The second aspect relates important group of nematodes known as entomopathogenic nematodes. These are used as biological control agents for insects, such as the Colorado potato beetle. A number of entomopathogenic nematode products are commercially available and some provide excellent insect control in specific situations. It is my opinion that this area has excellent potential for future insect control in MI potato production. Crop Rotation – Farming Systems.- In 1990, MPIC began to fund a long-term (10 year) crop rotation study designed to manage potato early-die. One of the first things learned was that late 1st-year alfalfa and 2nd-year alfalfa were very different than alfalfa grown in pots under greenhouse conditions. With very few exceptions, the highest tuber yields and least amount of potato early-die were associated with potato crops following two years of alfalfa. Another revelation was that when corn and wheat were removed to an 129 from the system, risk to crop loss caused by northern root-knot nematodes increases. By 1995, it became readily apparent that the potato early-die problem could not be resolved through simple crop rotation and that many aspects of the production system had to be taken into consideration. The project was redesigned into a farming systems trial which lead to a realization of the importance of overall soil quality in relation to the incidence of potato early-die. In 1979, MPIC began to fund a seven-year integrated project that was designed to investigate interactions between soil nutrition, potato early-die management and other potato production challenges. The 1979–1985 Michigan Potato Research Reports are full of data related to this project. Unfortunately, the project was about 10 to 15 years ahead of its time and both the researchers and the potato growers were unable to appreciate the potential significance of the work and plan adequately for the next steps. In the late 1990s, research with the techniques and equipment associated with precision agriculture were evaluated in relation to their use in potato early-die management. Commercial potato fields were mapped in relation to the physical and chemical properties of the soil and also for root-lesion nematode population densities and associated tuber yields. It was shown that the technology of precision agriculture was excellent for identification of sites and parts of fields with a high risk of potato early-die. The procedures of precision agriculture clearly demonstrated that under commercial field conditions, risk to early-die and low tuber yields were highly correlated with coarse textured soils, high population densities of root-lesion nematodes and various other soil factors associated with degraded or poor quality soil. Currently, there are two major farming system trials at the Montcalm Potato Research Station. One is designed to determine the impact of different tillage systems on potato early-die. This is a six-year trial. After the first six years, it appears that risk to potato early-die and root-lesion nematodes is less with a chisel-till system than with the conventional mold-board plot system. The second trial involves a two-year rotation with snap beans and sweet corn in addition to various cover crops and organic amendments. Soil Quality.- Today, it is well known that most nematodes in MI are not plant parasites like the root-lesion nematode. The vast majority of nematodes in MI feed on bacteria and fungi. It is through this process that they mineralize nutrients such as nitrogen, and make it readily available for plant growth and development. In many sites the highest population densities of these beneficial nematodes are in the litter layer or o-horizon and not below the soil surface. Population densities of bacterial and fungal feeding nematodes are frequently low in poor quality or degraded soils having a high risk to potato early-die. This frequently results in: 1) an increase in population densities of plant parasitic nematodes like the root-lesion nematode, 2) damage to basal roots, nodal roots, stolons, stolon roots and tuber roots, 3) disruption of soil nutrient cycling and reduced availability for use by the potato plant and 4) early plant death with low tuber yields. A high quality soil is one that resists degradation and responds to management. It contains a high diversity of different types of bacteria, fungi and fauna. This results in 130 the soil structure and enrichment properties necessary for optimal plant growth. Recent studies has shown that specific chemicals previously used in potato production for control of infectious diseases caused by fungi and insect pests can have direct and indirect negative impacts on some types of bacterial and fungal feeding nematodes. In addition to disrupting soil nutrient cycles, this allows nematodes that are less sensitive to these chemicals to increase their population densities. The root-lesion nematode is one that has been identified as being among those that are tolerant to these chemicals! Does this mean that potato early-die is actually an unexpected result of some of our farming practices? Recent investigations have also demonstrated that both inorganic fertilizers and herbicides can impact soil ecosystems in ways that alter nutrient cycling and may reduce overall soil quality. During the past 50 years, research on the role of soil fauna in relation to nutrient cycling has been very limited. It is now being recognized that soil fauna are an essential component of a high quality soil. By definition, a high quality soil is one that does not have a potato early-die problem. One long-term research project at Montcalm is designed to demonstrate the importance of high quality soil in relation to eliminating risk to potato early-die. This project was started at the end of the 2003 growing season. It is designed as a soil renovation initiative. Various crop rotations, soil tillage procedures and soil amendments are being used. The objective is to enhance the soil’s Structure Index and Enrichment Index through a long-term increase in the quality and quantity of soil organic matter. Detailed description of the Structure Index and Enrichment Index concepts in relation to potato production and reduction in potato early-die risk will be the topic of future articles and presentations. These terms were introduced to the Michigan potato industry at the 2004 Montcalm Potato Research Farm Field Day. Future Research Needs.- When I look back over the last 30 years, I believe that it was a mistake to separate Michigan potato research into its university disciplines. As all growers are very well aware, everything in a potato production system (late blight, Colorado potato beetle, early-die, plant genetics, plant nutrition, seed piece storage- quality, water use, soil quality, etc) impacts all other parts of the system. The original MPIC Integrated Project is an example of the type of research necessary for long-term success of the industry. This, however, must be supplemented with projects designed to provide short-term answers to immediate issues while work is progressing on how the system should really work (a work in progress that will never and should never be completed). My goal is to continue to provide the MI potato industry with chemical, biological, cultural and genetic potato early-die controls. I strongly believe, however, that the potato early-die problem can be eliminated through enhancement of soil quality. I plan to make this a major component of my MSU research activities and look forward to interacting with the MI potato industry on this topic. Early-Die Management Recommendations.- It is essential that every potato grower have an understanding of the early-die risk associated with each field. The best way to do this is through keeping high quality long-term records of potato yields, tuber quality and crop rotations for each site. If yield goals are not being obtained, soil and root tissue should be submitted to MSU Diagnostic Services for analysis for root-lesion nematodes, 131 Verticillim dahliae and early-die risk. The MSU early-die threshold chart can be used to determine future risk to early-die. It must be remembered that once seed pieces have been planted in a site with high risk to early-die, it is almost impossible to control the problem. Prevention, therefore is the only appropriate strategy. This should include rotations designed to reduce population densities of root-lesion nematodes and V. dahliae, use of varieties that have a history of yielding reasonably well in early-die sites, and maintenance of optimal soil nutrition and moisture. When population densities of root-lesion nematodes or V. dahliae exceed their individual or joint action thresholds, it may be necessary to apply a nematicide. If appropriate, chemigation with metham or fumigation with Telone II should be done the fall before potato planting. The nematicidal rate of metham is all that is necessary for early-die control. Application rates and methods are described on page 91 of MSU Extension Bulletin E-312, entitled 2004 Insect, Disease and Nematode Control for Commercial Vegetables. If desirable, Vydate should be applied at planting as described in MSU Ext Bulletin E-312. Use of this material as a foliar spray for Colorado potato beetle control will also reduce risk to early-die, providing a pre-plant or at-plant nematicide has also been used. If Mocap is used, every possible attempt should be made to incorporate this product. MSU research data show that the best way to use this product is on a pre-plant incorporated basis. Mid-season root densities of lesion nematodes can provide as excellent indication of the success of nematode control, early-die risk and potential tuber yield. The key to elimination of risk to early-die is currently believed to be soil organic matter. Both the quality and quantity of soil organic matter are thought to be important. Michigan potato growers should ask themselves the following four questions about each of their potato fields. - What was the soil organic matter content 150 years ago? - What was the soil organic matter content 10 years ago? - What is the current soil organic matter content? - What do you want the soil organic matter content to be 10 years from now? If the soil organic matter in a field has declined or is less than optimal for highly structured ecosystems that have the enrichment capabilities required for profitable potato production, the quality and quantity of the soil organic matter needs to be enhanced. During the past five years I have been surprised at how little soil organic matter exists in some coarse textured soils in MI and how much organic matter exists at other coarse textured sites. Anything that can be done to improve the long-term organic matter content of MI potato soils should reduce risk to early-die. In my soil classification system, soils with an early-die problem are degraded soils. Some of these respond to management and some do not. In either case, a soil renovation project is probably warranted to improve soil quality. During the past 10 years, science has begun to recognize that nematode community structure can be used as an indicator of the quality of soil, water and air. MSU Diagnostic Services offers a nematode community 132 structure assessment. This procedure is being used as part of the soil renovation project at the Montcalm Potato Research Farm Evaluation of Potato Varieties and Breeding Lines for Tolerance to Early-Die Since 1998, selected potato varieties and lines have been evaluated annually at the Montcalm Potato Research Farm for tolerance to the Early-Die Disease Complex. This work has been supported by the USDA Potato Grant and done in cooperation with the MSU Potato Breeding Program under the direction of Dr. Dave Douches. Twenty-two lines and varieties were evaluated in 2004. Five exhibited tolerance (Table 1), based on their relative high yields, lack of response to soil fumigation and support of normal root population densities of the root-lesion nematode, Pratylenchus penetrans (Table 2). The varieties-lines exhibiting PED tolerance included Boulder (formerly F373-3), WI 1201 (to be named Megachip), FL 1879 and UEC (Unknown Eastern Chipper). Boulder was described by Douches et al. in 2003 (Am. Potato Res. 80:345-352). Seventeen additional lines-varieties, including three PED susceptible standards, were susceptible to PED in 2004. There were no significant differences among the mid-season nematode population densities for any of the 22 varieties-lines. Mid-season root population densities associated with plants grown under non-fumigated conditions were higher than expected. A metham fumigation rate of 37.5 gpa was used in 2004; whereas, 75 gpa was used for the 1998-2003 evaluations. In summary, this research has demonstrated that one potato variety, Boulder (MS 702 x NY 88) and one line, MSE 228-1 (Russet Nugget x Spartan Pearl) are tolerant to PED and suitable for in PED risk sites (Table 3). Thirteen additional lines-varieties have exhibited tolerance, but require one to three additional years of evaluation before they can be classified as tolerant to PED. Ten varieties and three lines have been classified as susceptible to PED and should not be planted on PED risk sites without the use of soil fumigation, chemigation, non-fumigant nematicides or alternative PED managaement practices. Twenty-one lines have exhibited susceptibility, but require one to three additional years of evaluation before they can be classified as susceptible to PED. An additional nine lines have exhibited variable response to soil fumigation, indicating inconclusive results in relation to PED susceptibility-tolerance. One highly scab susceptible line, MSF 349-1RY (Rose Gold x WI 877) exhibited four years of resistance to PED without having any specific known source of resistance. This was followed by tolerant and susceptible responses in 2003 and 2004, respectively. It is thought that the highly unique resistant reaction was antibiotic mediated through the extensive Actinomycete pressure associated with this line. Impact of Tillage on Potato Tuber Yield and Root-Lesion Nematodes The research consists of two tillage systems (chisel plow and mold board plow) used in a three-year rotation with potato, wheat and corn. Clover is frost-seeded into the wheat. It is a six-year trial with two cycles of the three-year rotation. At the end of the first four years of the research project designed to determine the impact of tillage (chisel plow vs 133 mold board plow) on potato tuber yield and population dynamics of the root-lesion nematode (Pratylenchus penetrans), total tuber yields associated with the chisel plow system were 21% greater than those associated with the mold board plow system (Table 4). A-size tuber yields associated with the chisel plow system were 25% greater than those associated with the mold board plow system (Table 5). This response appeared to stabilize during the third year of the research project. Distinct patterns of root-lesion nematode population dynamics are becoming evident (Tables 5 & 6). At the beginning of the growing season, most the root-lesion nematodes associated with the wheat and cover are in root tissue (see 2003 MPIC Annual Report). In general, soil root-lesion nematode population densities at this time a lower than those associated with the plots previously in potato or corn (Table 6). Mid-season population densities of root-lesion nematodes are higher in corn and wheat/clover, compared to potato (Table 7). Soil Quality of Short Term Potato/Vegetable Rotation Systems The short-term potato/vegetable rotation trial was established by Dr. Snapp in 2001. It consists of nine cropping systems, in a two-year rotation, with both potato and snap bean produced annually for each of seven of the system. Each system is also done with and without a manure input. During the past 50 years, very little research has been done on the role of soil biology in relation to soil nutrient mineralization. This very important chapter of the soil science text book has yet to be written. The 2004 MPIC report on the nematode part of the cropping systems project will focus on the nature of the impacts of nematodes and other soil fauna on making nutrients available for potato production. Nematodes and other soil fauna are responsible for mineralization of about 38% of the biologically-mediated soil nutrient mineralization. Bacterial-feeding nematodes can be responsible for about 67% of the nutrients mineralized by soil fauna. Recently, nematologists have developed a comprehensive model for prediction of soil quality based on structural and enrichment indices. This system has been modified for use in Michigan and will serve as the basis for the soil quality assessment associated with this cropping systems research project. Soil Quality Restoration Trial In 2003, a soil quality restoration research site was established at the Montcalm Potato Research Farm. This is a cooperative projective with George Bird, Sieglinde Snapp, Willie Kirk and Mark Otto serving as co-principal investigators. The trial consists of four soil management systems: 1) Control (wheat/rye/potato, fumigated), 2) Wheat & Mustard (wheat/mustard & rye/potato), 3) Ultra-Biofumigant (mustard & rye/sudax/ mustard & rye/potato and 4) Ultra-Legume (vetch & rye/soybean green manure/vetch & rye/potato. Bacterial feeding nematodes were significant higher in the ultra –biofumigant treatment at the end of the 2004 growing season, compared to the control (Table 8). Population densities of fungivores, omnivores and carnivores were low, indicating a degraded soil quality in all of the systems. It appeared that control of plant-parasitic nematodes was obtained with both the soil fumigation treatment and the ultra- 134 biofumigant treatment. The mycorrhizae situation in regards to potato production is still unclear and the low population densities of oligocheates is an additional indication of a degraded soil with both poor structural and enrichment properties. Table 1. Tuber yields associated with the 2004 potato variety-line Montcalm Potato Research Farm field trial for evaluation of tolerance to Potato Early-Die (PED). PED tolerant Fumigated Non-fumigated Yield Adv P 359 cwt/a -5.6 0.476 353 cwt/a -11.3 0.330 327 cwt/a -32.1 0.226 316 cwt/a 0.445 247 cwt/a -11.7 0.377 0.32 298 cwt/a 220 cwt/a 220 cwt/a 283 cwt/a 302 cwt/a 290 cwt/a 351 cwt/a 286 cwt/a 300 cwt/a 193 cwt/a 269 cwt/a 254 cwt/a 341 cwt/a 248 cwt/a 5.4 8.6 7.3 6.0 6.0 10.7 11.4 15.0 18.7 18.7 20.1 23.2 24.3 39.9 0.373 0.220 0.453 0.330 0.300 0.111 0.27 0.170 0.133 0.112 0.041 0.109 0.045 0.021 271 cwt/a 248 cwt/a 216 cwt/a 21.4 28.6 44.9 0.107 0.040 0.042 lines-varieties 1. WI 1201 (Megachip) 339 cwt/a 2. FL 1879 313 cwt/a 3. H095-4 222 cwt/a 4. Boulder (F373-3) 317 cwt/a 5. UEC 218 cwt/a PED susceptible lines-varieties 1. FL 1833 2. FL 1867 3. FL 1922 4. H067-3 5. Spunta 6. G227-2 7. Marcy (NY112) 8. MI Purple 9. I005-20Y 10. E192-8Rus 11. E-018-1 12. F349-1RY 13. J461-1 14. H094-8 PED susceptible standards 1. Snowden 2. Atlantic 3. Russet Norkodah 314 cwt/a 239 cwt/a 236 cwt/a 266 cwt/a 320 cwt/a 321 cwt/a 391 cwt/a 329 cwt/a 356 cwt/a 229 cwt/a 323 cwt/a 313 cwt/c 424 cwt/a 347 cwt/a 329 cwt/a 319 cwt/a 313 cwt/a 135 Varieties-lines 1. WI 1201 (Megachip) 2. FL 1879 4. H095-4 5. Boulder (F373-3) 6. UEC PED susceptible lines-varieties 1. FL 1833 2. FL 1867 3. FL 1922 4. H067-3 5. Spunta 6. G227-2 7. Marcy (NY112) 8. MI Purple 9. I005-20Y 10. E192-8Rus 11. E-018-1 12. F349-1RY 13. J461-1 14. H094-8 PED susceptible standards 1. Snowden 2. Atlantic 3. Russet Norkodah 219 51 163 191 166 183 243 139 188 81 80 164 210 280 309 169 271 119 390 136 193 250 6 24 10 20 7 45 5 2 13 5 25 15 25 24 11 3 13 10 9 3 11 4 Table 2. Mid-season root population density of root-lesion nematodes (Pratylenchus penetrans) associated with 22 potato varieties-lines evaluated in 2004 for tolerance to Potato Early-Die (PED). PED tolerant Root-lesion nematodes per 100 cm3 soil Non-fumigated Fumigated 136 Table 3. Summary of 1998-2004 Michigan State University Potato Early-Die Nematode Tolerance-Resistance Research conducted at the Montcalm Potato Research Farm. _____________________________________________________________ Potato Early-Die Tolerant Variety-Line High yield in presence of potato early-die conditions with normal root-lesion nematode reproduction during four or more growing seasons. Boulder, MSF 373-3 (98, 00, 03, 04) MSE 228-1, Russet Nuggett x Spartan Pearl (98, 99, 00, 01) Probable Tolerance Variety-Lines WI 1201 (02, 04) MSH 095-4 (03) MSJ 316-A (03) NY 120 (01, 02) MSH 333-3 (01 MSE 028-1 (00) MSF 060-6 (00) Susceptible Varieties and Lines One to three years of additional PED evaluation are required. MSE 018-1 (99, 00, 03) MSJ 461-1 (03) Bannock Russett (02) MSH 094-8 (01, 02) WI 1431 (01) MSE 273-8 (00) 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, 03, 04) Russet Norkotah (02, 03, 04) Jacqueline Lee, MSG 274-3 (99, 00, 01, 02) Liberator, MSA091 (01, 02) Onaway (01, 02, 03) Superior (01, 02, 03) MSE 202-3 Rus (00, 01, 02, 03) MSE 149-5Y (98, 99, 00,01) Russet Burbank (03) Pike (02) MSF 099-3 (99, 00, 01, 02) Snowden (97, 99, 00, 01, 02, 03, 04) Goldrush (02, 03) 137 One to three years of additional PED evaluation are required. MSH 067-3 (03, 04) MSE 192-8Rus (03, 04) WI 1836-3Rus (03) MSK 061-4 (03) MSJ 167-1 (03) MSG 015-C (010 MSP 81-11-5 (00) MSH094-8 (03, 04) MSE 221-1 (00, 01, 03) NDTX 4271-SR (03) MSJ 317-1 (03) MSB 076G-3 (01) MSG 124-85 (00) WI 1368 (01) MSG 227-2 (03, 04) BO 766-3 (03) MS I005-20Y (03) MSF 099-3 (03) MSB 106-7 (00) MSH 026-3 Rus (01) WI 1386 (01) Variable response to soil fumigation, additional information required. MI Purple (00 tolerant, 01 susceptible, 02 tolerant, 03 susceptible, 04 susceptible) NY112, Marcy (01 tolerant, 02 tolerant, 04 susceptible) MSG 227-2 (00 susceptible, 01 tolerant, 02 tolerant) MSG 004-3 (00 susceptible, 01 tolerant) MSH 031-5 (00 tolerant, 01 susceptible) 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) Highly Unique Response MSF349-1RY (98, 00, 01, 02 resistant; 03 tolerant; 04 susceptible) Rose Gold x WI 877, highly susceptible to scab. The resistant reaction most likely was antibiotic mediated through extensive Actinomycetes pressure in 98, 00, 01 and 02, but not in 04. Table 3 (continued) Probable Susceptibility Inconclusive 138 2001 0.33 180 196 382 0.09 0.01 134 232 236 247 487 280 299 0.64 0.00 2002 2003 2004 Mean Table 4. 2001-2004 influence of alternative tillage systems on potato tuber yield (cwt/acre). _________________________________________________________________ Tillage _______________________________________________________________ Chisel Plow Mold Board Plow T Test P Value __________________________________________________________________ Table 5. 2001-2004 influence of alternative tillage systems on A-size potato tuber yield (cwt/acre). _______________________________________________________________________ Tillage _______________________________________________________________________ Chisel Plow Mold Board Plow T Test P Value ________________________________________________________________________ 2003 2004 Mean 0.00 0.09 0.01 340 103 202 452 159 256 220 165 0.31 0.23 272 2001 2002 203 139 2003 2004 160 c 62 b 6 a 2001 2002 111 c 86 abc 24 a 110 bc 97 bc 33 ab 42 a 43 a 67 ab 124 b 76 b 7 a 76 b 107 bc 6 a 102 c 131 bc 95 bc Corn Potato Wheat 78 b 124 bc 8 a Table 6. Early-season soil population densities of root-lesion nematodes (Pratylenchus penetrans)associated with alternative potato production till systems. _______________________________________________________________________ System _______________________________________________________________________ Chisel plow Corn Potato Wheat Mold board plow _______________________________________________________________________ Table 7. Mid-season (1.0 g root tissue) population densities of root-lesion nematodes (Pratylenchus penetrans)associated with alternative potato production till systems. _______________________________________________________________________ System _______________________________________________________________________ Chisel plow Corn Potato Wheat Mold board plow _______________________________________________________________________ 304 bc 46 a 132 ab 520 b 169 a 278 ab 316 b 130 a 270 ab 525 b 216 a 450 b Corn Potato Wheat 323 ab 134 a 424 b 382 c 54 a 87 a 453 b 154 a 423 b 2001 2002 2003 145 a 125 a 524 b 2004 140 Soil restoration treatment Table 8. 2004 end-of-season nematode population densities associated with the Montcalm Potato Research Farm soil restoration trial. _______________________________________________________________________ Nematode Guild (P) Control Wheat/Mustard Ultra-Biofumigant Ultra-Legume ________________________________________________________________________ Bacterivores (0.001) Fungivores (0.252) Herbivores (0.088) Omnivores (0.300) Carnivores (1.000) Mycorrhizae (0.113 Oligocheates (0.159) ________________________________________________________________________ 579 b 229 ab 13 30 18 0 50 1 44 a 9 2 4 0 25 3 265 ab 31 81 14 0 41 8 25 14 15 0 23 5 141 Funding USDA, MPIC Potato Insect Biology and Management Report to the Michigan Potato Industry Commission January 12, 2005 Edward J. Grafius, Walter L. Pett, Beth A. Bishop, Adam M. Byrne, and Eric N. Bramble Outline. I. II. III. Resistance of Colorado potato beetle populations to imidacloprid and thiamethoxam was evaluated for field populations from Michigan, as well as other locations in the Midwest and locations in the northeastern and western U.S. Field insecticide evaluations of registered and experimental insecticides. Effectiveness of Fulfill® treated potato plants for preventing transmission of PVY by aphids. I. Resistance of Colorado potato beetle populations to imidacloprid and thiamethoxam. Imidacloprid (Admire®, Provado®) has been the primary 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®), also a neonicotinoid, became available for commercial use. The similarities between these two compounds warrant careful scrutiny for resistance and cross-resistance development. Our objectives were to continue gathering data on baseline susceptibility to imidacloprid and thiamethoxam in Colorado potato beetle populations collected from commercial potato fields in 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, 21 Colorado potato beetle populations (six Michigan populations, 11 populations collected in other states, and four laboratory populations) were bioassayed with imidacloprid and/or thiamethoxam. 142 Methods During 2004, six Colorado potato beetle populations were collected from three different Michigan counties (Isabella, Mecosta, and Montcalm). Syngenta representatives and other cooperators also provided one population each from Delaware, Idaho, Massachusetts, New York, and Washington, two populations from Minnesota, and four populations from Wisconsin. Four strains maintained in the laboratory were also tested (Table I.1). Colorado potato beetle adults were either kept at room temperature (25±1o C) and fed foliage daily or, for longer term 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 ventral surface of the abdomen using a 50 µl Hamilton® microsyringe. Following treatment, beetles were placed in 100 mm diameter petri dishes lined with Whatman® No. 1 filter paper and provided with fresh potato foliage. They were kept at 25±1o C and the foliage and filter paper were checked daily and changed as needed. A preliminary screen was conducted on each population to determine relative susceptibility to imidacloprid and thiamethoxam by testing 10 beetles each with four 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, 9-15 beetles were treated with each concentration (three to five beetles per dish and three dishes per concentration). Beetle response was 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 and healthy 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. Dead and poisoned beetle numbers were pooled for analysis. Data were analyzed using standard log-probit analysis (SAS® System v8.01). Results Imidacloprid. The LD50 values for imidacloprid, 7 days post treatment, ranged from 0.027 µg/beetle (Newell) to 0.828 µg/beetle (Mecosta) for Michigan populations and from 0.031 µg/beetle (Eltopia, WA) to 7.675 µg/beetle (Little Creek, DE) for out-of-state populations (Table I.2, Figure I.1). For the first time in the Midwest, significant levels of resistance to imidacloprid were discovered. Beetles from the Mecosta (0.828 µg/beetle) and Sackett (0.572 µg/beetle) samples were 23-fold and 16-fold resistant to imidacolprid, respectively, compared to the susceptible New Jersey strain (LD50 = 0.036 µg/beetle). The two samples were from fields on the same farm, ca. 1 km apart, and are believed to be from the same population. The Sackett beetles were overwintering adults from 2003 and the Mecosta beetles were newly emerged summer adults. Populations from 143 Massachusetts and Delaware both showed high levels of resistance, providing results very similar to those from the same sites in previous years. The values for LD50 Minnesota, Washington, Wisconsin, and the rest of Michigan were at or near susceptible levels, consistent with results obtained for Colorado potato beetles from the same areas in previous years. Due to high mortality prior to testing, the Idaho population was not bioassayed, but the preliminary screens indicated that it was also a highly susceptible population. Thiamethoxam. LD50 values for thiamethoxam, 7 days post treatment, ranged from 0.018 µg/beetle (Isabella) to 0.339 µg/beetle (Sackett) for Michigan populations and from 0.033 µg/beetle (Hancock, WI) to 0.635 µg/beetle (Little Creek, DE) for out-of-state populations (Table I.3, Figure I.2). The Little Creek, DE (19-fold resistant) and Northampton, MA (11-fold resistant) populations both showed elevated levels of resistance to thiamethoxam when compared to the susceptible New Jersey strain (LD50 = 0.033 µg/beetle). Likewise, the Sackett (10 fold) and Mecosta (5 fold) populations showed higher levels of tolerance than we have previously detected in Michigan. All other field populations were consistent with results from previous seasons. As with imidacloprid, the Idaho population was not bioassayed, but the preliminary screens indicated it was a highly susceptible population. Susceptibility to imidacloprid (as measured by LD50) in field-collected Colorado potato beetle populations was highly correlated with susceptibility to thiamethoxam (Figure I.3). This result was also found in 1998, 1999, 2000, 2002, and 2003. This clearly shows that selection with imidacloprid over the past 10 years has also selected for resistance to thiamethoxam, although at a much lower level than imidacloprid resistance. Laboratory strain LD50 values ranged from 0.036 µg/beetle (New Jersey) to 8.995 µg/beetle (Hadley) for imidacloprid and from 0.033 µg/beetle (New Jersey) to 1.222 µg/beetle (Hadley) for thiamethoxam. The Hadley strain was collected from a commercial field in Massachusetts in 2003 and was the first field population to show elevated resistance to thiamethoxam (LD50 = 0.867 µg/beetle). Survivors from bioassays in 2003 were used to start a laboratory strain, and emergent adults from each generation have been selected with thiamethoxam doses targeting 60-90% mortality. After five generations, there has been an increase in the thiamethoxam LD50 value, but the difference was not significant due to overlapping confidence intervals. Despite frequent selection pressure, this strain still exhibits high variability in its response to thiamethoxam, suggesting that complex genetic factors may be involved. Adults from a susceptible strain that originated from an organic potato farm in Michigan’s Upper Peninsula were selected with thiamethoxam to start the S-Sel strain. Each generation, adults were selected with thiamethoxam doses targeting 60-90% mortality. The strain was maintained for nine generations, with bioassays conducted every third generation. The thiamethoxam LD50 increased from 0.044 µg/beetle (95% fiducial limit = 0.038-0.050) to 0.814 µg/beetle (95% fiducial limit = 0.695-0.982) by the ninth generation. Despite no exposure, the imidacloprid LD50 also increased from 0.031 µg/beetle (95% fiducial limit = 0.026-0.039) to 1.151 µg/beetle (95% fiducial limit = 144 0.930-1.643) by the ninth generation. These numbers are roughly a 25-fold increase in resistance to thiamethoxam and a 32-fold increase in resistance to imidacloprid, when compared to the New Jersey susceptible strain. In contrast, the Fiesta strain showed an entirely different pattern in response to selection with thiamethoxam. The Fiesta strain was started by selecting adults from a resistant strain collected at Long Island, NY. The strain was also maintained for nine generations and bioassayed every third generation. The thiamethoxam LD50 showed an initial increase by the third generation (from 0.241 µg/beetle to 0.455 µg/beetle), but then decreased by the ninth generation (0.290 µg/beetle). It is unclear why this population showed no significant increase in the level of resistance to thiamethoxam. Summary - Resistance to imidacloprid continues to increase in the eastern U.S. - Resistance to imidacloprid appeared for the first tiem in a field population in - Resistance to thiamethoxam, first detected in 2003, has appeared in two more the Midwest in 2004 locations in 2004 (DE and MA) - Laboratory selection shows that thiamethoxam resistance can increase rapidly with selection but results are variable - Under lab selection with thiamethoxam, resistance to imidacloprid remains stable or increases 145 Table I.1. Colorado potato beetle populations bioassayed for susceptibility to imidacloprid and thiamethoxam in 2004. Michigan populations Anderson Adults were collected by Mark Otto from a commercial potato field in Montcalm Co. on 19 July 2004. Isabella Adults were collected by Mark Otto from a commercial potato field in Isabella Co. on 9 August 2004. Mecosta Adults were collected by Mark Otto from a commercial potato field in Mecosta Co. on 26 July 2004. Montcalm Farm Adults were collected from the Michigan State University Montcalm Potato Research Farm in Montcalm Co. on 22 July 2004. Newell Adults were collected by Mark Otto from a commercial potato field near Trufant, Montcalm Co. on 27 and 31 July 2004. Sackett Adults were collected by Mark Otto from a commercial potato field in Mecosta Co. on 1 June 2004. Out-of-state populations Clear Lake, Minnesota Adults were collected by Brett Miller, Syngenta Crop Protection, Inc., from untreated edges of a commercial potato field near Clear Lake, MN on 19 August 2004. Coloma, Wisconsin Adults were collected by Steve Dierks, University of Wisconsin-Madison, from the Jacobs West field, Coloma Farms Inc. on 10 August 2004. Eltopia, Washington Adults were collected by Chris Clemens, Syngenta Crop Protection Inc., from untreated potatoes at a research farm in Eltopia, WA on 13 August 2004. Gyndon, Minnesota Adults were collected by Don Carey, North Dakota State University, from untreated potatoes near Gyndon, MN on 4 August 2004. Hancock, Wisconsin Adults were provided by Jeff Wyman, University of Wisconsin-Madison, from the Hancock Agricultural Research Station, Waushara Co. on 29 July 2004. Hudson, New York Adults were collected by Kurt Jones, Syngenta Crop Protection, Inc., from untreated potatoes at the Syngenta Eastern Region Technical Center, Hudson, NY on 2 June 2004. Little Creek, Delaware Adults were collected by Joanne Whalen, Extension IPM Specialist at University of Delaware, from a commercial potato field near Little Creek, DE on 23 June 2004. Northampton, Massachusetts Adults were collected by Sandra Shinn, Syngenta Crop Protection Inc., in Northampton, MA on 12 July 2003. Oakley, Idaho Adults were collected by Marty Schraer, Syngenta Crop Protection Inc., from untreated potatoes near Oakley, ID on 28 June 2004. Plover, Wisconsin Adults were provided by Jeff Wyman, University of Wisconsin-Madison, from a commercial potato field in Ellis, WI on 16 August 2004. Prairie, Wisconsin Adults were collected by Ronnie Wolosek, University of Wisconsin-Madison, from a commercial potato field in Plover, WI on 9 August 2004. Laboratory strains Fiesta Originally collected from Jamesport, Long Island, NY in August 1999 and maintained in the laboratory without selection. Starting in 2002, adults and subsequent offspring were selected with thiamethoxam doses targeting 60-80% mortality. Hadley Collected from Hadley, MA in July 2003. Adults from each generation have been selected with thiamethoxam doses targeting 60-80% mortality. New Jersey Adults obtained from the Phillip Alampi Beneficial Insects Rearing Laboratory, New Jersey Department of Agriculture. NY-Sel Collected from Long Island, NY in 1997 and adults were selected with imidacloprid doses targeting 60- 80% mortality to maintain resistance. S-Sel Collected from an organic farm near Calumet, MI in 1999. Adults from each generation were selected with thiamethoxam doses targeting 60-80% mortality. 146 Table I.2. LD50 values (µg/beetle) and 95% fiducial limits for Colorado potato beetle populations treated with imidacloprid at 7 days after treatment. Michigan populations Anderson Isabella Mecosta Montcalm Farm Newell Sackett out-of-state populations Clear Lake, MN Coloma, WI Eltopia, WA Gyndon, MN Hancock, WI Hudson, NY Little Creek, DE Northampton, MA Plover, WI Prairie, WI laboratory strains Fiesta Hadley New Jersey NY-Sel S-Sel LD50 0.088 0.058 0.828 0.047 0.027 0.572 0.106 0.108 0.031 0.044 0.066 0.076 7.675 2.327 0.120 0.072 1.164 8.995 0.036 7.207 1.151 95% fiducial limits 0.077-0.099 0.039-0.073 0.363-1.114 0.034-0.059 0.003-0.050 0.374-0.740 0.081-0.158 0.091-0.128 0.020-0.042 0.032-0.055 0.016-0.100 0.057-0.133 4.500-523.878 1.825-3.331 0.019-0.226 0.059-0.084 0.326-1.765 * 0.032-0.041 5.473-11.700 0.930-1.643 147 Table I.3. LD50 values (µg/beetle) and 95% fiducial limits for Colorado potato beetle populations treated with thiamethoxam at 7 days after treatment. Michigan populations Anderson Isabella Mecosta Montcalm Farm Newell Sackett out-of-state populations Clear Lake, MN Coloma, WI Gyndon, MN Hancock, WI Hudson, NY Little Creek, DE Northampton, MA Plover, WI Prairie, WI laboratory strains Fiesta Hadley New Jersey NY-Sel S-Sel LD50 0.057 0.018 0.171 0.056 0.036 0.339 0.045 0.056 0.046 0.033 0.047 0.635 0.355 0.072 0.042 0.290 1.222 0.033 0.687 0.814 95% fiducial limits 0.047-0.064 * 0.144-0.199 0.036-0.080 0.013-0.049 0.272-0.393 0.037-0.053 0.037-0.070 0.041-0.052 0.000-0.070 0.024-0.064 0.543-0.724 0.282-0.483 0.001-0.126 0.022-0.055 0.245-0.333 0.606-8.708 0.029-0.037 0.536-1.055 0.695-0.982 148 Dose lethal to 50% (µg/beetle) (7.7 µg) Imidacloprid - 2004 3 2.5 2 1.5 1 0.5 0 I M , l l e w e N Y N , n o s d u H E D , k e e r C e l t t i L A M , n o t p m a h t r o N I M , t t e k c a S I M , n o s r e d n A I M , a l l e b a s I I M , a t s o c e M I W , a m o l o C I M , m r a F m l a c t n o M Susceptible LD50 I W , r e v o l P I W , e i r i a r P N M , n o d n y G A W , a i p o t l E N M , e k a L r a e l C I W , k c o c n a H Figure I.1. Doses lethal to 50% of Colorado potato beetle populations to imidacloprid. 149 Thiamethoxam - 2004 1 Dose lethal to 50% (µg/beetle) 0.5 Susceptible LD50 0 A M , n o t p m a h t r o N E D , k e e r C e l t t i L I M , l l e w e N Y N , n o s d u H I M , t t e k c a S I M , n o s r e d n A I M , a l l e b a s I I M , a t s o c e M I W , a m o l o C I M , m r a F m l a c t n o M I W , k c o c n a H I W , r e v o l P I W , e i r i a r P N M , n o d n y G N M , e k a L r a e l C Figure I.2. Doses lethal to 50% of Colorado potato beetle populations to thiamethoxam 150 0.8 0.6 0.4 0.2 ) e l t e e b / g µ ( 0 5 D L m a x o h t e m a i h t 0 0 y = 0.0792x + 0.0735 R2 = 0.8271 2 4 6 8 imidacloprid LD50 (µg/beetle) Figure I.3. Correlation between susceptibility to imidacloprid and thiamethoxam for all field populations tested in 2003 (n=14). 151 II. Field insecticide evaluations of registered and experimental insecticides. The Colorado potato beetle (CPB) is one of the most widespread and destructive insect pests to potato crops in the northeastern United States and Canada. Their ability to develop resistance to insecticides makes it very important to continue testing new chemistries and the efficacy of existing compounds. Methods Fourteen insecticide treatments (Table II.1) were compared to two untreated controls at the Michigan State University Montcalm Research Farm, Entrican, MI for control of CPB. ‘Atlantic’ potatoes were planted 12 in. apart, with 34 in. row spacing on 6 May 2004. Treatments were replicated four times in a RCB design. Plots were 40 ft long and three rows wide. Admire, Belay, Platinum, and one rate of V10112 (seven treatments total) were applied as in-furrow sprays at planting, using a single-nozzle hand-held boom (30 gpa, 30 psi). Foliar treatments were first applied at greater than 50% egg hatch on 14 Jun. Subsequent first-generation sprays for most treatments were applied on 22 Jun, 29 Jun, and 6 Jul (depending on treatment, Table 1). Post-spray counts of CPB adults and larvae (small and large) on five randomly selected plants for the middle row of each plot were made 2 d after each foliar application. Defoliation ratings were taken on 6 Jul and 22 Jul by assessing five randomly chosen plants from the middle row of each plot. On 1 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 with Fisher’s Protected LSD test (p=0.05). There were significant differences between treated and untreated plots in the seasonal means of egg masses, small larvae, large larvae, and adults (Table II.1). Numbers of small larvae include larvae that were still on the egg masses and had not begun to feed on foliage, resulting in high variability in these numbers. All treatments resulted in significantly fewer large larvae and adults than in the untreated plots. There were also significant differences among treatments in overall yield and defoliation ratings (Table II.2). 152 Table II.1. Seasonal mean number of Colorado potato beetle egg masses, small larvae, large larvae, and adults per plant. Treatment/formulation Admire 2F Admire 2F Belay 16 Belay 16 Clutch Clutch Leverage 2.7SE Platinum FS Platinum FS Provado Spintor 2 SC V10112 20 SG V10112 20 SG V10112 20 SG untreated check 1 untreated check 2 P value Means within a column followed by different letters are significantly different (P<0.05, Fisher’s Protected LSD). Data transformed for analysis with log (x+1), means presented in non-transformed units. Seasonal mean of 1st-generation CPB Application dates at planting at planting at planting at planting 14 Jun, 22 Jun 14 Jun, 6 Jul 14 Jun, 29 Jun, 6 Jul at planting at planting 14 Jun, 29 Jun 22 Jun, 29 Jun, 6 Jul 14 Jun, 29 Jun 14 Jun, 6 Jul at planting Large Larvae Adults 0.5 bc 1.5 b 0.5 bc 1.9 b 0.0a 0.2ab 0.2ab 0.0a 0.2ab 0.2a 0.2ab 0.2a 0.2a 0.2ab 0.3ab 0.2a 0.5 bc 0.2a 0.2ab 0.4a 0.5a 0.3ab 0.2ab 0.2a 0.1a 0.5a 3.0 c 0.4abc 1.8 d 13.0 d 1.0 c 9.2 d 0.0001 0.0001 Rate 13 fl oz/acre 16 fl oz/acre 12 oz/acre 18 oz/acre 1.5 oz/acre 2.0 oz/acre 3.75 fl oz/acre 6.5 oz/acre 8.0 oz/acre 3.75 oz/acre 4.5 oz/acre 60 g AI/acre 80 g AI/acre 120 g AI/acre Egg Masses 0.5 cde 0.5 de 0.0a 0.0ab 0.5 de 0.4 cde 0.4 cde 0.2abcd 0.3abcde 0.3 cde 0.4 cde 0.4 cde 0.4 cde 0.3 cde 0.6 e 0.2abc 0.0112 Small Larvae 3.0 bc 3.3 c 0.3a 0.0a 2.7 cd 3.6 cdef 3.2 cdef 0.6ab 0.4ab 3.3 cd 8.6 fg 3.1 cdef 3.5 cdef 3.0 cde 11.1 g 6.9 efg 0.0001 153 Table II.2. Mean yield (weight/40 row ft) harvested and defoliation ratings taken on two sampling dates. Rate 13 fl oz/acre 16 fl oz/acre 12 oz/acre 18 oz/acre 1.5 oz/acre 2.0 oz/acre 3.75 fl oz/acre 6.5 oz/acre 8.0 oz/acre 3.75 oz/acre 4.5 oz/acre 60 g AI/acre 80 g AI/acre 120 g AI/acre Treatment/formulation Admire 2F Admire 2F Belay 16 Belay 16 Clutch Clutch Leverage 2.7SE Platinum FS Platinum FS Provado Spintor 2SC V10112 20 SG V10112 20 SG V10112 20 SG untreated check 1 untreated check 2 P value Means within a column followed by different letters are significantly different (P<0.05, Fisher’s Protected LSD). a Size A = tubers greater than 2 inches. Size B = tubers that are 2 inches or less. b Defoliation rating: 1, no defoliation; 2, 1-25% defoliation; 3, 26-50% defoliation; 4, 51-75% defoliation; 5, 76-100% defoliation. Yield (lb/40 row ft) Defoliation ratingb 20 Jul Application dates at planting 1.6ab 1.4a at planting 1.0a at planting at planting 1.0a 1.2a 14 Jun, 22 Jun 1.0a 14 Jun, 6 Jul 1.2a 14 Jun, 29 Jun, 6 Jul at planting 1.2a 1.0a at planting 1.2a 14 Jun, 29 Jun 1.2a 22 Jun, 29 Jun, 6 Jul 14 Jun, 29 Jun 1.2a 1.1a 14 Jun, 6 Jul 1.4a at planting 3.2 c 2.2 b 0.0001 Size Aa 63.6 d 57.8 bcd 63.8 d 62.0 cd 58.3 bcd 46.2ab 57.9 bcd 58.2 bcd 62.2 cd 46.4ab 55.0 bcd 58.4 bcd 60.1 bcd 49.2 bcd 33.4a 48.1abc 0.0207 Size Ba Total 3.8 3.0 3.6 3.5 3.4 3.8 4.1 4.2 2.9 3.0 3.9 3.5 3.1 4.2 2.8 2.9 0.3313 67.4 e 60.8 bcde 67.4 e 65.5 de 61.7 bcde 50.0abc 62.0 bcde 62.4 bcde 65.1 cde 49.4ab 58.9 bcde 61.9 bcde 63.2 bcde 53.5 bcde 36.1a 50.9abcd 0.0121 6 Jul 1.0a 1.1a 1.0a 1.0a 1.0a 1.2a 1.0a 1.0a 1.0a 1.0a 1.0a 1.0a 1.2a 1.2a 2.4 c 1.8 b 0.0001 154 III. Effectiveness of Fulfill® treated potato plants for preventing transmission of PVY by aphids. Methods A foliar field rate (2.75 oz/A) application of Fulfill® was applied to 16 virus-free 4-week old ‘Atlantic’ potato plants grown in plastic pots. A population of potato aphids was established on ‘Atlantic’ potato plants that were rub inoculated with PVY infected tubers. Aphids were maintained on these plants for one week prior to the start of the test. Five PVY infectious potato aphids were placed on individual Fulfill® treated plants 1, 3, and 6 days after spray application. Additionally, five PVY infectious aphids were placed on individual virus-free untreated plants on the same dates as above to serve as a positive control. Each treatment was replicated four times. Aphid survival was determined 6 days after the aphids were placed on the plants. Results No living aphids were found on any of the Fulfill® treated plants regardless of when the aphids were placed on the plants. The number of aphids on the untreated plants increased to >20, 7 days after initial placement. The potato plants that were rub inoculated with PVY infected tubers and meant to serve as the infection source were not infected by this technique. No PVY symptoms were observed in any of the plants. We plan to repeat the experiment starting January 17, 2005 as we now have PVY infected plants. 155 Potato Vine Desiccation Study Christy Sprague and Gary Powell, Department of Crop and Soil Sciences Snowden potatoes were planted at the Montcalm research station to evaluate chemical desiccation of potato foliage. Herbicides were applied on August 12 to actively growing potatoes (approximately 20% flowering), and again eleven days later on August 23 to ‘yellowing’ potatoes past flowering. Two treatments of ‘Rely’ (glufosinate) were applied as a single application, at both timings, at a rate of 3 pints of product per acre. ‘Regone’ (diquat) was applied as a split application at 1 pint per acre at both application timings. ‘Aim’ (carfentrazone) 2EC was applied as a split application at 1.6 fluid ounce followed by 2.0 fluid ounce, and another treatment of 2.0 fluid ounces at the second application timing only. Potato stem desiccation, potato leaf desiccation, and common lambsquarters control were visually evaluated at 7 and 19 days after herbicide application. Potatoes were harvested 33 days after application and evaluated for tuber yield and quality. Rely applied at the 1st application timing resulted in greater stem desiccation than Rely applied at the 2nd application. Reglone and Aim applied in split applications resulted in potato leaf and stem desiccation similar to a single application of Rely in the 1st application. A single application of Aim applied at the 2nd timing resulted in less desiccation of potato stems and leaves than when applied at the 1st application. Potato yield was significantly higher in the untreated control than any of the desiccation treatments. When Aim was applied as a split application there was a trend towards higher potato yield as compared to the other desiccation treatments, although this was not significant. No significant difference in potato quality or specific gravity were observed between any of the treatments in this study. 156 SOLTU POTATO CHEAL Common lambsquarters MSU Weed Science Research Program B L. POST Aug-23-04 Chenopodium album L. Potato Vine Kill Trial ID: POT-01 Study Dir.: Sprague, Powell Conducted: Montcalm Investigator: MSU Crop and Soil Science Weed Control Date Planted: May-17-04 Row Spacing: 34 IN Variety: Snowden No. of Reps: 4 Population: % OM: 2.1 Soil Type: Sandy Loam pH: 5.3 Plot Size: 10 X 30 FT Design: RANDOMIZED COMPLETE BLOCK Tillage: Spring Moldboard Plow. Previous Crop: Corn Crop and Weed Description Weed Code Common Name Scientific Name 1. Crop Code Common Name 1. Application Description Application Timing: Date Treated: Time Treated: % Cloud Cover: Air Temp., Unit: % Relative Humidity: 65 Wind Speed/Unit/Dir: 0 mph - Soil Temp., Unit: Soil/Leaf Surface M: 5 5 Soil Moist (1=w 5=d): 2 Crop Stage at Each Application Crop Name: SOLTU SOLTU Height (In.): Stage (L): Weed Stage at Each Application Weed 1 Name: CHEAL CHEAL Height (In.): Stage (L): Weed Density (plants/sq. ft.) Date: Aug-12-04 Weed Name: CHEAL Density: 2-10 ft Application Equipment Appl Sprayer Speed Nozzle Nozzle Nozzle Nozzle Boom A B A POST Aug-12-04 1:45 PM 11:00 AM 75 64 F 90 78 F 63 3 mph n 71 F 5 5 4 Type AirMix 11003 38" AirMix 11003 38" Height Spacing Width GPA Carrier PSI 27 27 120" 19 Water 120" 19 Water 20" 20" 15-20 20%flower 15-20 yellowing 40-50 many 40-50 many Type Cub Cub A A 1 MPH 3.8 3.8 Size 63 F B B 157 1 1 Rely Rely Grow Appl Stg Code MSU Weed Science Research Program Form Form Rate Conc Type Rate Unit Potato Vine Kill Trial ID: POT-01 Study Dir.: Sprague, Powell Conducted: Montcalm Investigator: MSU Crop and Soil Science Weed Control Weed Code Crop Code Rating Data Type Rating Unit Rating Date Trt-Eval Interval Trt Treatment No. Name 1 2 3 3 3 3 4 5 5 5 5 6 6 LSD (P=.05) Standard Deviation CV A 0.025 LB A/A post 1 A % V/V post 0.032 LB A/A L. post B 1 % V/V L. post B A 1 post A 0.25 % V/V post 1 L. post B 0.25 % V/V L. post B Reglone Activator 90 NIS Reglone Activator 90 NIS 0.032 LB A/A post 1 % V/V post Aim MSO Aim MSO Untreated Control 15.3 9.9 22.87 9.0 5.8 10.39 13.6 8.8 16.3 14.4 9.4 31.0 EC L EC L 43 85 L. post B Aim MSO EC L L L L L 2 2 2 2 55 PT/A PT/A PT/A PT/A 3 3 L L 0 25 0 68 0 36 post A 64 73 A A 63 78 2 38 56 88 45 74 0 33 95 95 97 38 98 84 14.8 9.8 11.65 SOLTU stem % desicat SOLTU overall % desicati SOLTU leaf % desicat Aug-19-04 Aug-19-04 Aug-19-04 Aug-19-04 Aug-31-04 Aug-31-04 Aug-31-04 Sep-14-04 7 DA-A SOLTU Skin Set 0-10 CHEAL control percent CHEAL control percent SOLTU stem % desicat SOLTU leaf % desicat 33 DA-A 19 DA-A 19 DA-A 19 DA-A 7 DA-A 7 DA-A 7 DA-A 91 78 98 24 92 85 56 86 0 89 79 89 0 0 0 0 0 0 11.9 7.9 10.3 13.7 9.1 13.45 0.0 0.0 0.0 158 1 1 3 3 Rely Rely Grow Appl Stg Code MSU Weed Science Research Program Form Form Rate Conc Type Rate Unit Potato Vine Kill Trial ID: POT-01 Study Dir.: Sprague, Powell Conducted: Montcalm Investigator: MSU Crop and Soil Science Weed Control Weed Code Crop Code Rating Data Type Rating Unit Rating Date Trt-Eval Interval Trt Treatment No. Name 1 2 3 3 3 3 4 5 5 5 5 6 6 LSD (P=.05) Standard Deviation CV A 0.025 LB A/A post 1 A % V/V post 0.032 LB A/A L. post B 1 % V/V L. post B A 1 post A 0.25 % V/V post 1 L. post B 0.25 % V/V L. post B Reglone Activator 90 NIS Reglone Activator 90 NIS 0.032 LB A/A post 1 % V/V post Aim MSO Aim MSO 0.0025 0.0017 0.18 Untreated Control 44.2 29.3 17.64 1.17 0.77 185.9 EC L EC L L. post B Aim MSO 0.0 0.0 0.0 EC L L L L L 2 2 2 2 0 0 0 0 0.923 0.924 0.923 0.5 0.0 0.922 1.0 0.8 0.3 243 172 0.927 139 153 143 PT/A post 0.925 PT/A PT/A PT/A L L A 0 0 2 A A 0.0 146 SOLTU SOLTU SOLTU Stem End HollowHeart Specific Gravity 0-10 Sep-14-04 Sep-14-04 Sep-14-04 Sep-14-04 Sep-14-04 Sep-14-04 Sep-14-04 33 DA-A 33 DA-A SOLTU CWT/A USA #1 SOLTU CWT/A B's SOLTU CWT/A Knob's SOLTU CWT/A Total 33 DA-A 33 DA-A 33 DA-A 33 DA-A 33 DA-A 0-10 19 16 16 16 26 1.1 0.0 0.3 0.5 0.0 160 170 159 260 198 15 0.0 161 7.9 5.2 28.84 1.52 1.01 315.3 48.9 32.4 17.57 159 Funding: MPIC Summary Report for the 2003-2004 Dr. B. F. (Burt) Cargill Potato Demonstration Storage Brian Sackett, Chris Long, Dick Crawford, Todd Forbush (Techmark, Inc.), Steve Crooks, Dennis Iott, Keith Tinsey, Tim Young, Jason Walther, Troy Sackett, Randy Styma and Ben Kudwa Introduction This is a summary report of the 2003-2004 Dr. B.F. (Burt) Cargill Potato Demonstration Storage Annual Report Volume 3. This report is designed to provide a short summary of the 2003-2004 storage committee activities. To obtain a copy of the full 2003-2004 Demonstration Storage Report please contact the Michigan Potato Industry Commission office (517-669-8377) or Chris Long at Michigan State University (517-355-0271 ext.#193). The full report will be provided to you free of charge. Summary and Highlights The 2003 growing season was notably dry. The Montcalm County region had over 7.5 inches of rainfall which was under the 15 year average for this location. There were a limited number of days that the day time high temperature reached 90 ºF or above. These conditions resulted in slightly lower specific gravity numbers for our region and some increases in internal defects such as stem end discoloration and internal necrosis. The storage season was dry and this helped to reduce the number of pathological issues that are more common in wetter seasons. The goal of the MPIC Storage and Handling Committee for the 2003-2004 storage season was to develop storage profiles on three promising advanced seedlings. Liberator (MSA091-1) is from the potato breeding program at Michigan State University. UEC*, now “Beacon Chipper”, is a clone that has an unknown origin and pedigree but is of great interest in Michigan, and is likely to be jointly released by the states of Michigan and Maine. Megachip (W1201) originated from the breeding program at the University of Wisconsin, Madison, overseen by Dr. Jiming Jiang. The committee’s main objective was to determine what the optimal storage temperature was for each variety, while maintaining acceptable storage quality. Also of interest was the level of pressure bruise damage that may be incurred by each variety at a given storage temperature. A brief description of each varieties storage performance is provided. The goal for the variety Liberator was to evaluate its longevity at a given storage temperature. The potatoes in bulk bins 2 and 3 were planted and harvested at the same time. The committee chose to hold bin 2 at 52 ºF and positioned this bulk bin for an April-May shipping period. Bin 3 was designated for a shorter term storage profile and was held at 55 ºF. The Megachip variety, based on its maturity, was slated for a long term storage profile and plans were made to store it at 50 ºF. It was planned to be 160 processed during a March to May shipping window. The committee chose to evaluate UEC on the basis of its planting date and how the planting date would impact the physiological age and storability of this variety. The early planted UEC’s were held at 51 ºF and slated for January/February sale. The UEC’s in bin 6 were planted later and positioned for sale in March or April. The holding temperature for this bin was designated to be 48 ºF. The results for the bulk bins were as follows: The Liberators (MSA091-1) in bulk bin 2 and 3 struggled with internal sugar defects all season. All attempts to remove sugar by increasing internal respiration appeared not to have a great impact. The bins were not processed due to our inability to clean-up internal sugars. Megachip (W1201) was shipped for processing, but due to internal sugars and a high level of black spot bruise, possibly resulting from high specific gravity and cold harvest conditions, the load was rejected. Beacon Chipper (UEC) in bins 5 and 6 were shipped successfully on February 26, 2004 and April 1, 2004 with 5% and 1% defects noted at the processing plant, respectively. Promising varieties in the box bin trial were MSG227-2 and MSJ461-1. These varieties will be considered for larger scale evaluations in the 2004-2005 storage season. *Unknown Eastern Chipper (UEC), now “Beacon Chipper”, was previously tested and labeled as the clone B0766-3. B0766-3, a USDA Beltsville potato clone from Dr. Kathleen Haynes’ Breeding Program, Beltsville, Maryland is being considered for release. The official seed source for B0766-3 is the Uihlein Seed Farm, NY. The two clones UEC and B0766-3 have undergone fingerprint analysis at Michigan State University and the pattern of B0766-3 does not match that of UEC. Thus, the UEC clone tested was incorrectly referred to as B0766-3. No known variety or breeding clone matches the UEC fingerprint pattern to date. The origin and pedigree of UEC is unknown. UEC seed that was tested and reported in the 2001-2002, 2002-2003 and 2003-2004 Cargill Potato Demonstration Storage Annual Report Volumes 1, 2 and 3 was obtained from Devoe Seed Farm, Limestone, ME. The initial seed stock was obtained from the Maine State Seed Farm which is the Porter Seed Farm. The Michigan State University fingerprint data of UEC shows an identical match between the Devoe Farm seed and the tissue culture plantlets at the Porter Seed Farm from which all the seed labeled as UEC has been derived. BEACON CHIPPER Unknown Eastern Chipper, (UEC) 161