1999 MICHIGAN POTATO RESEARCH REPORT VOLUME 31 Michigan State University Agricultural Experiment Station In Cooperation With The Michigan Potato Industry Commission THE MICHIGAN POTATO INDUSTRY COMMISSION February 18, 2000 To All Michigan Potato Growers & Shippers: The Michigan Potato Industry Commission, Michigan State University’s Agricultural Experiment Station and Cooperative Extension Service are pleased to provide you with a copy of the results from the 1999 potato research projects. This report includes research projects funded by the Michigan Potato Industry Commission, the USDA Special Grant and special allocations by the Commission. Additionally, the Commission expresses appreciation to suppliers of products for research purposes and special grants to the Commission and researchers. Providing research funding and direction to principal investigators at MSU is a function of the Michigan Potato Industry Commission’s Research Committee. The Commission is pleased to provide you with a copy of this report. Best wishes for a prosperous 2000 season. The Michigan Potato Industry Commission THE MICHIGAN POTATO INDUSTRY COMMISSION • 13109 SCHAVEY RD., STE. 7 • DEWITT, Ml 48820 • (517)669-8377 Table of Contents Page Introduction and Acknowledgments, Weather and General Management.......................................................................................................... 1 Michigan State University Potato Breeding Program — 1999 Status Report David S. Douches, K. Jastrzebski, Chris Long, K. Zarka, Kim Walters, Joe Coombs and D. Bisognin ........................................................ 5 1999 Potato Variety Evaluations Douches, R.W. Chase, K. Jastrzebski, R. Hammerschmidt, D.S. W. Kirk, C. Long, K. Walters, J. Coombs and J. Greyerbiehl ........................ 19 1999 On-Farm Potato Variety Trials Dr. Dick Chase, Dr. Dave Douches, Don Smucker, David Glenn, Paul Marks and Jim Isleib........................................................................................... 46 Effect of Whole Seed Piece Weight, Planting Density and a Soil Stimulant on Yield in Commercial Seed Potato and Chip Potato Fields Brendan A. Niemira, William W. Kirk, Robert Schafer, Jeffrey M. Stein and R. Scott Shaw ......................................................................55 Potato Seed Cutting and Seed Treatment Application: Agronomic Effect of Timing on Plant Emergence and Tuber Yield Brendan A. Niemira, William W. Kirk, Robert Schafer, Jeffrey M. Stein and R. Scott Shaw ......................................................... 61 1999 Potato Nematode Research Report George W. Bird ..............................................................................................................71 Insect Management in Potatoes —1999 Research Report Beth Bishop, Adam Byrne, John Lekovish, David Mota-Sanchez, Haddish Melakeberhan, Nathan Cottrell, Walter Pett, Chang-hui Rui, Robert Hollingsworth, Mark Whalon and Edward Grafius ............................................................................................................ 84 Page Combining Varietal Resistance with Managed Fungicide Applications for the Control of Potato Late Blight W.W. Kirk, D.S. Douches, R. Hammerschmidt, J.A. Stein, R.S. Schafer, R. Scott Shaw and B.A. Niemira .................................................103 The Role of Dimethomorph Within a Potato Late Blight (Phytophthora infestans) Control Program. Mixture Partners and Optimal Application Timing J.M. Stein, W.W. Kirk, R.L. Schafer and M.R. Durkin .................................... 109 Chemical Control of Potato Late Blight 1999 W.W. Kirk, R.L. Schafer, J.M. Stein, R. Scott Shaw and K. Baker..........113 Control of Seed-Borne Late Blight (Phytophthora infestans Mont. De Bary) Development from Treated Potato Seed-Pieces with Trichoderma atroaviride W.W. Kirk and J. McBeath............................................................................ 130 Spatial and Temporal Dynamics of Potato Production Sites in Relation to Precision Agriculture and Integrated Crop Management Systems Roger Brook, George Bird, Darryl Warncke, Scott Swinton, Dave Lusch, Mark Otto, Nate Hough, Don Smucker and Rich Hodupp............................................................................................................... 143 Calcium and Metham Effects on Potato Tuber Yield and Quality George Bird and Darryl Warncke ................................................................... 151 Potato Storage Experiments—Two Decades of Progress in Technology and Management Dr. Burt Cargill, Dr. Roger Brook, Dr. Ray Hammerschmidt, Robert Fick, Todd Forbush, Keith Tinsey and John Mills........................ 154 1999 MICHIGAN POTATO RESEARCH REPORT R.W. Chase, Coordinator INTRODUCTION AND ACKNOWLEDGMENTS The 1999 Potato Research Report contains reports of the many potato research projects conducted by MSU potato researchers at several locations. The 1999 report is the 31st report which has been prepared annually since 1969. This volume includes research projects funded by the Special Federal Grant, the Michigan Potato Industry Commission 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 of 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 acknowledge 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. A special thanks goes to Dick Crawford for the management of the MSU Montcalm Research Farm and the many details which are a part of its operation. Thanks also go to Chris Long, CSS Potato Technician. Also, a special thanks to Jodie Schonfelder for the typing and preparation of this report and to Don Smucker, Montcalm CED for maintaining the weather records from the MRF computerized weather station. WEATHER The weather during the 1999 growing season was cooler than 1998 but slightly warmer than the 15 year average (Table 1). There were nine days that the temperature reached 90F or above and seven days in April that the temperature was below 32F. The fall and harvest season weather was excellent. Rainfall for April through September was 30.16 inches which was 8 inches above the 15 year average (Table 2). Rainfall recorded during April and May were the highest for those months during the past 15 years. Irrigation applications were six and were completed in early August. Table 1. The 15 year summary of average maximum and minimum temperatures during the growing season at the Montcalm Research Farm. May May Min June June Max Min Max July July Min empty table cell April April Max Min Max 38 36 36 31 32 58 70 70 60 77 61 74 52 72 56 NA NA 64 71 60 51 70 54 68 66 57 51 66 50 64 54 59 75 60 59 71 40 34 33 34 31 31 31 37 37 56 34 69 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 15-YR. AVG. 44 46 46 46 34 43 47 42 45 43 45 44 39 51 48 44 71 77 80 82 81 77 82 76 74 78 81 75 79 77 77 78 46 50 56 53 53 55 59 50 55 55 57 57 56 56 55 54 81 82 86 88 83 79 81 76 81 79 82 76 80 82 84 81 55 59 63 60 59 58 60 54 61 60 60 55 57 58 62 59 August August September September 6-Month 6-Month Average Average Max Min Max Min Max Min 75 77 77 84 79 78 80 75 79 75 82 80 73 81 76 78 54 51 58 61 55 57 57 51 60 55 65 59 55 60 56 57 70 72 72 71 71 72 69 69 64 73 70 70 69 76 73 71 50 50 52 49 44 47 47 46 46 51 45 51 50 52 48 48 48 71 49 73 52 76 50 75 74 46 NA NA 74 52 69 46 70 50 71 49 50 72 50 69 69 48 75 52 51 73 72 49 Table 2. The 15 year summary of precipitation (inches per month) recorded during the growing season at the Montcalm Research Farm. Year April 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 15-YR. AVG. 3.63 2.24 1.82 1.82 2.43 1.87 4.76 3.07 3.47 3.84 3.65 2.46 2.02 2.40 5.49 3.00 May 1.94 4.22 1.94 0.52 2.68 4.65 3.68 0.47 3.27 2.63 1.87 3.99 3.13 2.21 5.07 2.82 June 2.78 3.20 0.84 0.56 4.85 3.53 4.03 1.18 4.32 6.04 2.30 6.28 3.54 1.82 5.82 3.41 July 2.58 2.36 1.85 2.44 0.82 3.76 5.73 3.51 2.58 5.16 5.25 3.39 2.80 0.40 4.29 3.13 August September 4.72 2.10 9.78 3.44 5.52 4.06 1.75 3.20 6.40 8.05 4.59 3.69 2.71 2.22 5.46 4.51 3.30 18.60 3.32 5.36 1.33 3.64 1.50 3.90 3.56 1.18 1.38 2.96 1.46 3.05 4.03 3.90 Total 18.95 32.72 19.55 14.14 17.62 21.51 21.45 15.33 23.60 26.90 19.04 22.77 15.66 12.10 30.16 20.77 GROWING DEGREE DAYS Table 3 summarizes the cumulative, base 50F growing degree days for May through September. The total GDD were 2,401, similar to 1991 but 200 GDD less than 1998 which was the warmest during the past decade. Table 3. Growing Degree Days* - Base 50F. empty table cell Cumulative Monthly Totals Cumulative Monthly Totals Cumulative Monthly Totals May Cumulative Monthly Totals June July August September Cumulative Monthly Totals 1991 1992 1993 1994 1995 1996 1997 1998 1999 452 282 261 231 202 201 110 427 317 1014 718 698 730 779 681 635 932 865 1632 1210 1348 1318 1421 1177 1211 1545 1573 2185 1633 1950 1780 2136 1776 1637 2180 2070 2491 1956 2153 2148 2348 2116 1956 2616 2401 *1991 and 1992 data calculated from Vestaburg weather station in Montcalm County (Dr. Jeff Andresen, Geography). 1993-1998 data from the weather station at MSU Montcalm Research Farm (Don Smucker, Montcalm County Extension Director). PREVIOUS CROPS, SOIL TESTS AND FERTILIZERS The general potato research area was planted to field com in 1998, harvested, leaving the stubble until plowing in the spring of 1999. The plot area was not fumigated and potato early die was a serious problem in 1999. The soil test analysis for the general crop area are as follows: lbs/A P2O5 lbs/A pH 6.0 473 K2O 276 lbs/ACa 700 lbs/AMg 120 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 report. Application Analysis Rate Nutrients (N-P205-K20) Broadcast at plowdown At planting At emergence Sidedress 0-0-60 19-17-0 46-0-0 46-0-0 125 lbs/A 18 gpa 125 lbs/A 200 lbs/A 0-0-75 25-23-0 58-0-0 92-0-0 HERBICIDES AND PEST CONTROL Hilling was done in late May, followed by pre-emergence Dual and Sencor at 2 pints/A and .67 lbs/A, respectively. Admire was applied at planting and Cygon was applied twice. Fungicides used were Bravo ZN and Polyram 80DF in the 11 applications. MICHIGAN STATE UNIVERSITY POTATO BREEDING PROGRAM 1999 STATUS REPORT Funding: Federal Grant/MPIC David S. Douches, K. Jastrzebski, Chris Long, K. Zarka, Kim Walters, Joe Coombs, and D. Bisognin Department of Crop and Soil Sciences Cooperators: R.W. Chase, Ray Hammerschmidt, Ed Grafius Willie Kirk and George Bird INTRODUCTION At MSU we conduct a multi-disciplinary program for potato breeding and variety development that integrates traditional and biotechnological approaches. We conduct variety trials of advanced selections (at MSU and in grower fields), through conventional crosses we develop new genetic combinations in the breeding program, 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. In addition, our program utilizes genetic engineering as a tool to introduce new genes to improve varieties and advanced germplasm. We feel that these in-house capacities (both conventional and biotechnological) put us in a position to respond and focus upon the most promising directions and can effectively integrate the breeding of improved chip-processing and tablestock potatoes. The breeding goals at MSU are based upon current and future needs of the Michigan 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, extended cold storage) and cooking quality, bruise resistance, storability, along with shape, internal quality and appearance. 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. PROCEDURE I. Varietal Development Each year, during the winter months, over 500 crosses are made between 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 being used as the breeding base for the program. Approximately 35,000 seedlings are grown annually for visual evaluation at the Montcalm and Lake City Research Farms as part of the first year selection process of this germplasm each fall. Then each selection is then evaluated for specific gravity and chip processing. These selections each represent a potential variety. This generation of new seedlings is the initial step to breed new varieties and this step is an on-going process in the MSU program. This step is followed by evaluation and selection at the 8-hill and 20-hill stages. The best selections out of the four-year process are then advanced for testing in replicated trials (Preliminary, Adaptation, Dates-of-Harvest, Grower-cooperator trials, North Central Regional Trials, Snack Food Association Trials and out-of-state trials) over time and locations. II. Germplasm enhancement We have a "diploid" (2x chromosomes) breeding program in an effort to simplify the genetic system in potato (which normally has 4x chromosomes) and exploit more efficient selection of desirable traits. In general, diploid breeding utilizes haploids (half the chromosomes) from potato varieties, and diploid wild and cultivated tuber-bearing relatives of the potato. These represent a large source of valuable germplasm, which can broaden the genetic base of the cultivated potato and also provide specific desirable traits such as tuber dry matter content, cold chipping and dormancy, along with resistance to disease, insects, and virus. 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. The diploid breeding program germplasm base at MSU is a synthesis of six species: S. tuberosum (adaptation, tuber appearance), S. phureja (cold-chipping, specific gravity), S. tarijense and S. berthaultii (tuber appearance, insect resistance), S. microdontum (late blight resistance) and S. chaconese (specific gravity, low sugars, dormancy and leptine-based insect resistance). III. Integration of Genetic Engineering with Potato Breeding Genetic engineering offers 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 is set up to use Agrobacterium-mediated transformation to introduce genes into important potato cultivars. We presently have genes that confer resistance to PVY, Colorado potato beetle, potato tuber moth, broad-spectrum disease resistance via the glucose oxidase (GO) gene, late blight resistance with the resveratrol synthase (RS) gene and cold/frost resistance (COR15). We also have the glgC16 gene (ADP-glucose pyrophosphorylase (AGPase) or starch gene) from Monsanto to modify starch and sugar levels in potato tubers. Using this gene (from Monsanto) we can manipulate the metabolism of the cultivated potato to limit the accumulation of reducing sugars during low temperature storage and to increase starch content. AGPase is a key enzyme in the starch biosynthetic pathway responsible for catalyzing the conversion of glucose-1-phosphate to ADP-glucose. Although the biochemical basis for the accumulation of reducing sugars at low temperatures has yet to be fully elucidated, this process is intimately associated with the process of starch synthesis and degradation. Monsanto provided evidence for AGPase as the rate-limiting step for starch synthesis and produced transgenic potato plants containing a bacterial AGPase gene (glgC16) under the control of the tuber-specific patatin promoter and targeted to the amyloplast via a plastid transfer peptide. IV. Evaluation of Advanced Selections for Extended Storage In 1999, the Michigan Potato Industry Commission constructed a demonstration storage facility to evaluate management systems to achieve extended storage of potatoes for chip processing. Fifteen lines and check varieties were placed in this facility this October. Throughout the winter we will be sampling the tubers for their ability to chip-process from 42F. RESULTS AND DISCUSSION For the 1999 field season over 500 crosses were planted and evaluated. Of those, 80% were crosses to select round whites. During the 1999 harvest, approximately 750 selections were made from the 35,000 seedlings grown at the Montcalm Research Farm and Lake City Experiment Station. Following harvest, specific gravity was measured and chip-processing (from 42F storage) will be tested January, 2000 directly out of storage. This storage period allows enough time for reducing sugars to accumulate in these selections. Atlantic (50F chipper) and Snowden (45F chipper) are chipped as check cultivars. When the 1998 single-hill selections were chipped directly out of 42F storage, about 20% of the single-hill selections had acceptable chip color. These selections are being evaluated as 8-hill selections in 1999. Of the 8-hill selections from 1998, 30% of the 400 clones chip-processed with acceptable color directly out of 42F, while the 200 twenty-hill selections, 25% had acceptable chip color from 42F storage. Thirty of these clones were tested in the 1999 Preliminary Trial. In addition to chip processing qualities, some of these lines also show resistance to scab and/or late blight. In summary, the frequency of good chip-processors in the breeding program has increased over the previous years even with in spite the more stringent screening temperature (42 vs. 45F storage). One of our critical objectives is to breed potato varieties that will not accumulate reducing sugars in cold storage (40F). We commonly call these varieties "cold chippers". Breeding for cold-chipping varieties requires a broad genetic base. From a broad base we can then combine genes for cold-chipping while maintaining other important characteristics for agronomic performance and host plant resistances. The probability of identifying many, cold-chippers in the initial rounds of crosses that have the required agronomic traits has been low. Therefore, we have been using a three-tier storage temperature evaluation (50, 42 and 40F) for chip processing. The testing procedure on the selections is as follows. Processing at 50F is initiated in December. Those selections that process out of 50F storage are then tested from 42 storage in January. The good 42F chippers are then tested from 40F in February. We also believe that there is no long-term value in 2-4 week reconditioning out of 40F storage. All chip-processing in our program is done directly from cold storage, however, reconditioning studies are done at times to differentiate 42F or 40F chip-processors. At this time we consider any selections that chip from 45/42F as cold sweetening resistant. These selections then form the parental material for our next cycle of crosses. From these crosses we hope to find a higher percentage of 42 and 40F chippers. If this occurs, then we can expect to continue to find a greater percentage of cold-chippers in the further rounds of crossing and selection. Based upon the pedigrees of the parents we have identified for breeding cold-chipping potato varieties, we have a diverse genetic base. We believe that we have at least eight cultivated sources of cold-chipping. We have made various hybrid combinations with these parents from which to pyramid cold-chipping traits, and the hybrid populations have been grown out, selected and evaluated (Table 1). We now have advanced into the crossing block these new MSU selections that have chip quality directly out of 42F storage. For the 1998 selections, following the 42F chip-processing results, these good processors were chipped out of 40F in February. Of all of the 8-hill and 20-hill selections, only 3 of the lines chipped acceptably from 40F. Examination of pedigrees shows that at least two different cold-chipping germplasm sources have been combined in these selections. One of our objectives is also to develop improved cultivars for the tablestock industry. Efforts have been made to identify lines with good appearance, low internal defects, high marketable yield and resistance to scab. From our efforts we have identified mostly round white lines, but we have a number of yellow fleshed and russet selections which carry many of the characteristics mentioned above. We are also looking for a dual-purpose russet, round white and improved Yukon-type yellow-fleshed potatoes. Some of the tablestock lines were tested in on- farm trials in 1999, while others were tested under replicated conditions at MRF. Our goal now is to 1) improve further on the level of scab resistance, 2) incorporate resistance to late blight, 3) select more russet lines and introduce the Bt-cry3A gene into Yukon Gold, Norwis, Onaway, MSG274-3 (late blight resistant line) and MSE018-1. In 1999, in addition to the grower-cooperator trials, we also initiated a large-scale field testing program (1 acre blocks per line on five farms) between the breeding program, the seed industry and the commercial growers called CHIPS2001 (see attachement 1). We have targeted four lines in 1999 (A091-1, NT-1, F099-3 and G274-3) and will add two lines in year 2000 (G227-2 and E246-5). We have also initiated a grower testing program for tablestock cultivars called Tablestock One-on-One (see attachement 2). In this program we work with specific growers to identify their agronomic and market needs and match up these needs with seed of advanced selections from the breeding program. Three growers participated in 1999. We also distributed a number of advanced selections to other states (California, North Carolina, Nebraska, Pennsylvania and Ontario) for agronomic evaluations. As of December, 1999 the lines that performed well include A091-1, B106-7, B107-1, E018-1, E149-5Y, E228-1, E221-1 and NT-1. Table 2 lists some of the potential lines for grower trials in year 2000. Diploid Germplasm Enhancement In recent years the diploid germplasm (20 of the best lines with differing pedigrees) formed the crossing block to generate new populations. From this material we expect to find improved diploid Solanum species parents to be used in crosses to select new varieties. These crosses were planted in 1996 and again in 1999. We have found some selections that have acceptable chip-processing quality and tuber appearance. In 1999, about 10% of the populations evaluated as single hills were diploid. From this breeding cycle, we plan to screen the selections through the three-tier storage temperature evaluation for chip­ processing. Through GREEEN funding, we were able to initate 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. In the fall, we made selections from 3,000 progeny that we segregating for leptine synthesis and day length adaptation. This winter we will determine the processing quality of the selections and the leptine levels in the foliage (via HPLC analysis). This overall germplasm enhancement effort is the base from which long-term genetic improvement of the potato varieties in the MSU breeding program is generated. Late Blight Breeding and Genetics A high priority objective of the breeding program is to identify sources of late blight resistance and use these sources for breeding varieties with late blight resistance. Based upon greenhouse screenings, we have been using USDA/ARS and European sources of late blight resistance in our crossing block. The objectives of this specific study were 1) to evaluate the potential use of LB resistant parents in varietal breeding, 2) to identify individuals that have good LB resistance combined with good tuber quality and acceptable maturity, and 3) to evaluate a selection procedure for developing LB resistant cultivars. Eight clones (B0718-3, Bertita, Bzura, Greta, Libertas, Stobrawa, Tollocan and Zarevo) with reported LB resistance and different genetic backgrounds were crossed with susceptible clones adapted to the north central United States. Seedlings of 95 families (4,750 seedlings) were evaluated in the field in 1997 based upon tuber appearance, number and defects. A total of 408 clones (9%) were selected for LB evaluations in the greenhouse and in the field using A2 mating type US-8 genotype of P. infestans. Clones with a < 10% foliar infection in the greenhouse or relative area under the disease progress curve < 0.30 in the field were selected for re-evaluation in 1999, resulting in 119 (29%) putative LB resistant clones. The LB resistant parents differed in both the ability to transmit LB resistance and in the level of LB resistance transmitted to the offspring. Tollocan and B0718-3 transmitted LB resistance in a higher level and to a higher percentage of the progeny than any other LB resistant parent evaluated in this study, while Zarevo, Greta, Libertas, and Stobrawa transmitted only moderate LB resistance to the offspring. Cluster analysis was able to rank the clones in discrete groups differing in LB resistance. Using the cluster group with intermediate resistance to LB as a threshold resulted in 80 (67% of 119 clones) selected clones. Among them, 19 clones had vine maturity readings equal or less than mid-season (Table 3). Five-LB families were represented by the clones, in which 12 clones of Tollocan, three clones of B0718-3, two clones of Stobrawa and one clone of each Libertas and Zarevo families. Using LB resistant parents as Tollocan and B0718-3 it is of value to select first for tuber quality and other agronomic characteristics than for LB resistance. We are planning to cross some of the best selections to combine different late blight resistance sources. This strategy may lead to late blight resistance with a more durable and broader genetic base. In 1999 we initiated a set of studies (via GREEEN) to identify the genes in potato associated with late blight resistance. If we can identify the genes that contribute to late blight resistance we feel that we could more effectively breed varieties with durable late blight resistance. We have focused this research on one 2x population that derives its resistance from S. microdontum and a 4x population that derives its resistance from MSG274-3. During the summer of 1999 the populations were planted at the Muck Soils Research Farm for disease evaluation and DNA marker analysis was started in the lab this fall. In addition, we are collaborating with the Scottish Crops Research Institute on this gene mapping project so that we can draw their expertise and experience in this area of research. A fall visit to Scotland helped us learn the AFLP technology so that we can quickly generate a genetic map and begin to identify the late blight resistance genes. We are also using SSR markers. The advantage of the specific SSRs we are using is that they were previously identified to be linked to late blight resistance genes in other potato lines. Our germplasm enhancement efforts have been focusing on screening wild Solatium species for late blight resistance. Numerous plant introductions from Mexico and South America were tested in the greenhouse late blight chamber. The selections that showed the strongest resistance were retested. As a result, we have identified approximately 30 lines with strong resistance that constitute a broad genetic base to work with. These lines have been crossed to our best diploid lines to introgress the late blight resistance. These populations will be planted in the field in year 2000. Genetic Engineering The Colorado potato beetle, Leptinotarsa decemlineata Say, is the leading insect pest of potato (Solanum tuberosum L.) in northern latitudes. Host plant resistance is an important tool in an integrated pest management program for controlling insect pests. During the 1998 and 1999 seasons, field studies were conducted to compare natural (glandular trichomes and leptine glycoalkaloids) and engineered (Bt-cry3A, Bt-cry5, and Bt- cry5 + glandular trichomes transgenic potato lines) host plant resistance mechanisms of potato for control of Colorado potato beetle. Twenty-two different potato lines representing five different host plant resistance mechanisms were evaluated in a choice situation under natural Colorado potato beetle pressure at the Montcalm Research Farm in Entrican, Michigan. Greenhouse-grown tissue-culture plantlets were transplanted to the field between rows of a susceptible guard Snowden in a randomized complete block design consisting of four replications of ten plants each. Observations were recorded weekly for a visual estimation of percent defoliation by Colorado potato beetles, the number of egg masses, eggs per mass, and the number of first, second, third, fourth instar larvae, and adults. The Bt-cry3A transgenic lines and high leptine expressing lines were most effective for controlling defoliation by Colorado potato beetle adults and larvae (Figure 1). Although one Bt-cry5 transgenic had significantly lower defoliation than the other Bt-cry5 lines, in general the Bt-cry5 lines were not as effective as the Bt cry3A transgenic lines The glandular trichome and Bt cry5 + glandular trichome lines proved to be ineffective in this choice field situation. Based on these results, the Bt-cry3A transgenic and high leptine lines are effective resistance mechanisms that could be incorporated in a resistance management program for control of Colorado potato beetle. The program has been conducting transformations of potato to introduce a variety of transgenes. Currently we have genetically engineered plants that express the Bt-cry3A gene to control the Colorado potato beetle, the glucose oxidase and resveratrol synthase genes for disease resistance, and the AGPase gene for low sugars and high solids. In 1999, we had an extensive field testing of our transgenic lines. In general, the transgenic lines had agronomic and tuber characteristics of the non-transgenic parent line. Of interest, we have targeted transformation with the AGPase gene towards lines that have excellent chip processing, but a below average solids content (i.e. MSE149-5Y). Using this strategy, we hope to broaden our opportunities for identifying cold-chipping cultivars. Development of Bt-crv5-transgenic potato lines for host plant resistance to potato tuber moth in Egypt Dave Douches and Joe Coombs, traveled to Egypt to harvest three field trials involving Bt-transgenic potato lines (at CIP and AGERI) (planted February 1999). The purpose of these trials was to obtain field data toward agronomic performance (CIP location) and resistance to potato tuber moth (PTM) damage to the foliage and tubers (CIP and AGERI) of these Bt-transgenic potato lines. These trials are now in their third year at AGERI and second year at CIP, and are under the supervision of Drs. Taymour El-Nasr and Magdy Madkour. In addition to the field trial harvest and evaluation, our other objective was to establish linkages with the Egyptian private and public sector (scientists and regular people) seed and commercial growers to disseminate information regarding the potential commercial use of Bt-transgenic potato lines. The field trials in 1999 involved transgenic lines derived from Atlantic (chip­ processing), L235-4 (breeding line with glandular trichome-based natural resistance), and Spunta (tablestock). Atlantic and L235-4 lines have been field tested in Egypt and the US since 1997 and 1996, respectively, while 1999 was the first field trial for Spunta lines. The CIP field trials were harvested June 7 and in the PTM trial, tubers were evaluated for PTM damage. On the average, the percent tuber moth damage was 27 and 28% for the Spunta and Atlantic cultivars, whereas the Bt-transgenic Atlantic lines averaged between 80-88% clean tubers, and the four best Bt-transgenic Spunta lines averaged 99.8-100% clean tubers. The Bt-transgenic L235-4 line (L235-4.13) had 99% clean tubers compared to the 84% clean tubers observed with L235-4. These tuber results parallel the laboratory tuber bioassays of Douches, et al. (1998) and Mohammed et al. (in Press). Following field evaluation, the clean tubers from the CIP trials were placed in the nahwalla at CIP to evaluate PTM tuber damage after one and two months of storage. In the Agronomic trial at CIP, the yields were low compared to commercial fields, however, the Bt-transgenic Spunta and Atlantic lines performed comparably to their non-transgenic cultivar. The PTM trial at AGERI was harvested June 8, 1999. On this trial, the tuber moth infection was low. Only 10% of the Atlantic tubers were damaged by PTM. The best Bt-transgenic lines showed less tuber damage (92-100% clean tubers). The clean tubers from these trials will be used for tuber bioassays and as seed for a fall trial at AGERI. Table 1. Promising Early Generation Cold-Chipping Selections from Michigan State University. LINE MSI111-A MSJ042-3 MSJ093-5 MSJ107-4 MSJ143-4 MSJ147-1 MSJ163-7R MSJ165-1 MSJ167-1 MSJ212-2 MSJ223-1 LATE BLIGHT RESISTANCE empty table cell COLD CHIPPING SPECIFIC GRAVITY (H= >1.080) PARENTAGE PARENTAGE MALE FEMALE empty table cell empty table cell X empty table cell empty table cell X empty table cell empty table cell X X X X X X X X X X X X X H H H H H H H H H H H E251-1 BRODICK E041-1 E230-6 ND01496-1 ND2417-6 PIKE PRESTILE P84-13-12 S438 ZAREVO OP ZAREVO S440 ZAREVO S440 S440 ZAREVO S440 E250-2 ZAREVO E250-2 Table 2. Potential Lines for 2000 Grower Trials TABLESTOCK COMMENTS empty table cell MSE018-1 MSE028-1 MSE221-1 MSE228-1 MSE228-11 MSF313-3 empty table cell SCAB R empty table cell empty table cell empty table cell MSF373-8 SCAB MR MSG004-3 empty table cell MSG050-2 empty table cell MSG141-3 MSG274-3 empty table cell (MSE048-2Y) empty table cell LBR empty table cell empty table cell MSE149-5Y (MSG145-1Y) SCAB MR empty table cell MSE192-8RUS SCAB R MSE202-3RUS SCAB R (MSF087-3RUS) SCAB R (MSH026-3RUS) SCAB R empty table cell empty table cell empty table cell (MSE040-6RY) MI PURPLE WOLVERINE () = Limited Seed PROCESSING COMMENTS MSA091-1 MSE018-1 MSE246-5 MSF099-3 MSF313-3 MSF373-8 (MSG015-C) SCAB SFA R empty table cell SCAB SFA MR empty table cell empty table cell SCAB MR SCAB R SCAB R SCAB MR empty table cell empty table cell empty table cell SCAB SFA R empty table cell empty table cell empty table cellempty table cell (MSH094-8) (MSH095-4) (MSH098-2) MSNT-1 MSG227-2 MSH031-5 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cellempty table cell empty table cell empty table cell empty table cell empty table cell Table 3. Late blight clones selections in 1999 based on LB reaction and maturity Clone LB Other Specific Gravity Parent Parent B0718-3(M) E251-1 B0718-3 W870 W871 B0718-3 C127-3 Libertas Stobrawa Yukon Gold Stobrawa Yukon Gold Tollocan Chaleur Tollocan(M) Conestoga Tollocan(M) Krantz Tollocan(M) Lenape Tollocan(M) Lenape Tollocan(M) NY88 Tollocan(M) Pike Tollocan(M) Snowden Tollocan(M) Snowden Tollocan(M) Superior Tollocan(M) W870 Tollocan(M) W877 Zarevo(M) MS716-15 J310-3 J319-1 J319-7 J399-1 J452-3 J452-4 J455-4 J456-2 J458-2 J459-3 J459-4 J461-1 J462-2 J464-1 J464-4 J466-3 J467-6 J468-1 J488-4 * 1 = Resistant and 2 = intermediate resistant to late blight. 1998 1.083 1.086 1.075 1.097 1.086 1.083 1.066 1.082 1.075 1.087 1.076 1.074 1.080 1.089 1.076 1.081 1.098 1.086 1.104 Tuber Appearance Rating 1998 Chip Score RAUDPC Cluster 1998 Groups* Vine Maturity Ratings 1 1 1 1 2 2 2 1 2 2 3 1 3 4 2 . 2 2 3 1 3 2 3 4 6 5 6 5 4 5 5 3 3 3 3 6 2 3 5 0.455 0.378 0.423 0.539 0.502 0.549 0.268 0.342 0.095 0.157 0.16 0.071 0.106 0.237 0.222 0.256 0.553 0.395 0.509 2 2 2 2 2 2 2 2 1 1 1 1 1 2 2 2 2 2 2 3 3 2 3 3 3 3 3 3 3 3 3 3 3 3 3 2 2 3 CHIPS2001 1. Choose 3-4 lines; Start T.C. propagation January, 1999 2. Transplant 1000 plants/line to GH 3. Transplant to field at Lake City (MSU) 4. Harvest tubers (10-20 cwt/line) 5. Plant field by Seed Grower (1/2 - 1 acre) 6. Harvest tubers (125-250 cwt) May 15, 1999 June 15, 1999 October, 1999 Spring, 2000 Fall, 2000 7. Plant commercial fields (5 acres) & seed field (1 acre) Spring, 2001 8. Harvest 300-500 cwt/line Send load to chip-processor Fill research storage bins Seed harvest for 2002 Fall, 2001 9. Chip-process storage samples Winter, 2002 Candidate Chip Line Priority Pedigree Comments MSG274-3 MSF099-3 MSNT-1 MSA091-1 MSG227-2 MSE246-5 1 2 3 4 4 4 Late blight resistant, dual table/chip Cold-chipping, exc. internals & shape Scab resistant, exc. internals Tollocan X Chaleur Snowden X Chaleur - MS702-80X Norchip Scab resistant Prestile X MSC127-3 Cold-chipping, scab resistant, exc. shape E55-27 X W870 Cold-chipping, scab resistant Tablestock One-on-One Michigan State University Potato Breeding Program The MSU potato breeding program has been generating advanced selections that have commercial potential. Many of these selections have been tested in MSU research trials and in grower-cooperator trials around the state. This year we initiated a program we call Tablestock One-on-One to cooperate with tablestock growers to evaluate specific selections on specific farms. We want to work with individual growers to understand their agronomic needs, production constraints and market targets. In this way we can identify specific advanced selections that you can test on your farm. At this time, we can supply seed for testing at small levels (10 lbs. to 100 lbs.). The goal of the on-farm testing is to compare our advanced selection to your current variety. Therefore, we want to compare the MSU line side-by-side with your currently-grown variety. Our suggestion is to plant the lines at a minimum of 3-4 row plots (depending on your planter). In this way the middle rows could be sampled for yield checks. If you are interested in testing lines or learning more about the program, please contact Dr. Dave Douches, potato breeder, at Michigan State University. You can also check out the variety images on the MSU Potato Breeding and Genetics web site (www.msu.edu/user/douchesd). Dr. Dave S. Douches Associate Professor Depart. of Crop and Soil Sciences Michigan State University East Lansing, MI 48824 517-353-3145 517-353-5174 FAX douchesd@pilot.msu.edu MSU Tablestock Breeding Lines MSE192-8RUS: A russet tablestock selection. The tubers are long with an attractive russet appearance like Russet Norkotah. In comparison to Russet Norkotah it has a bright white flesh, a good taste and expresses PVY symptoms. Its strengths are scab resistance, low incidence of internal defects, and bruise resistance. The vines have early-mid season maturity. We view this as a potential Russet Norkotah replacement. MSB106-7: A high yielding, long white type. Internal quality is excellent with a bright white flesh, however, specific gravity in only 1.070. It has performed well in Louisiana and Nebraska. We regard this as a niche variety. MSF313-3: A high yielding selection with acceptable specific gravity for chip-processing. It has cold-chipping (45°F) potential. The tubers have an attractive appearance and have excellent internal quality. Scab resistance is above average. We regard this as a potential Onaway replacement. MSG141-3: A round white selection. Tubers are smooth and round with a bright skin. Internal quality is excellent and yield potential is above average. The vines have a mid-season maturity. We regard this as a potential Onaway replacement. MSF373-8: A very high yielding selection with acceptable specific gravity for chip-processing. It will chip out-of-the-field and from 50°F storage. Produces large tubers with a low incidence of internal defects. Scab tolerance is intermediate. This selection also has tablestock potential. We regard this as a potential Onaway/Ontario replacement. MSB107-1: A high yielding selection which produces large tubers that have excellent internal characteritics. Scab tolerance is intermediate and maturity is medium-late. We regard this as a potential Onaway/Ontario replacement. MSE018-1: A very high yield potential, high specific gravity, and moderate tolerance to scab. It has a late maturity, large vine and some reduced susceptibility to late blight. Tuber appearance is bright and smooth with a round-oval shape. We regard this as a potential Katahdin replacement (baker). MSE221-1: A high yielding selection with scab resistance and a moderately early vine maturity. Tubers are netted with an attractive appearance. The internal qualitites of the tubers are excellent. We regard this as a potential Superior replacement. MSE149-5Y: A light yellow-fleshed selection with smooth, round tubers that have a bright appearance. Specific gravity is low but the selection has high yield potential. Internal qualities are excellent and the vine maturity is medium-early. We regard this as a potential Norwis replacement. MSE228-11: A selection with smooth, round tubers that have a bright attractive appearance. Internal qualities are excellent and scab resistance is intermediate. Plants have a heavy tuber set (can lead to high percentage of B sized tubers). Vine maturity is mid-season. MSG274-3: An oval/oblong table stock selection with a high tuber set. The tubers have the bright skinned, smooth and attractive appearance that is typical of many European cultivars. The tubers have very low incidence of internal defects and good baking quality. The strength of this selection is its strong foliar resistance to the US8 genotype of late blight. Vine maturity is similar to Snowden. MSG145-1Y: A selection with smooth, round tubers with a bright attractive appearance. The flesh is golden yellow. Vine maturity is mid-season. Tubers are bruise resistance. We regard this selection as a potential Yukon Gold replacement. MSE040-6RY: A red-skinned tuber with yellow flesh. The tubers are smooth and the red color is equivalent to Chieftan. Yield is intermediate and has an early vine maturity. We regard this as a novelty type. 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. We regard this as a novelty type. Mean Relative Area Under the Defoliation Curve (RAUDC) Values of Host Plant Resistant Potato Lines by Colorado Potato Beetles Funding Fed. Grant/MPIC 1999 POTATO VARIETY EVALUATIONS Douches, R.W. Chase, K. Jastrzebski, R. Hammerschmidt, D.S. W. Kirk, C. Long, K. Walters, J. Coombs and J. Greyerbiehl Departments of Crop and Soil Sciences and Botany and Plant Pathology Michigan State University East Lansing, MI 48824 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 and 50 F storage), dormancy (at 50F), as well as susceptibilities to late blight, common scab, Fusarium dry rot, Erwinia soft rot and blackspot bruising are determined. Seven field experiments were conducted at the Montcalm Research Farm in Entrican, MI. They were planted in randomized complete block design with four replications. The plots were 23 feet long and spacing between plants was 12 inches. Inter-row spacing was 34 inches. Supplemental irrigation was applied as needed. The round white tuber types were harvested at two dates (Date-of-Harvest trial). The other field experiments were the Russet, North Central Regional, European, Adaptation and Preliminary 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, dormancy, disease tests, bruising and cooking tests were taken. Chip quality was assessed on 25-tuber samples, taking two slices from each tuber. Chips were fried at 365°F. The color was measured visually with the SFA 1-5 color chart. Tuber samples were also stored at 42 and 50°F for chip-processing out of storage in January and March. A. Round White Varieties Results Six varieties and 21 breeding lines were compared at two harvest dates. Atlantic, Snowden, Superior and Onaway were used as checks. The plot yields were below average in the early harvest (98 days), however, and a moderate yield increase was observed for the second harvest date (140 days). The low yields and early vine senescence were attributed to potato early die. Tuber specific gravity readings were above average. The results are presented in Tables 1 and 2. In the early harvest trial NY112, E018-1, NY120, Atlantic and MSF313-3 had the highest yields of the 27 entries. At the later harvest MSE018-1, NY112, Atlantic and MSF313-3 were still the top yielders along with MSE228-1. NY112, Atlantic and MSE018-1 were also top yielders in the on-farm processing trials, while MSE228-1 was the top yielder in the on-farm tablestock trial. Internal brown spot and hollow heart incidence were low within the trial, however vascular discoloration was more prevalent as in 1998. NY112 was the only line with significant hollow heart in the oversize tubers. Variety Characteristics MSA091-1 - a MSU selection for chip-processing with strong scab resistance. Yields in 1999 were below average, but it has performed well in other states (Nebraska, Pennsylvania and California) the late blight trials indicate a reduced susceptibility to late blight. It is in the national SFA and the North Central regional trials. It is also in the CHIPS2001 program. MSE018-1 - a MSU chip-processing selection with high yield potential. It was an outstanding yielder in the MSU and on-farm trials the past three years. Specific gravity is high and it has a good general appearance. Scab tolerance is intermediate and it has a reduced susceptibility to late blight. This line was in the 1998 SFA Trials. Chip-processing has been variable in the on-farm trials. MSE149-5Y - a MSU tablestock selection. It has high yield potential and produces attractive round tubers with a bright skin and light yellow flesh. It has been a top yielder in the on-farm trials. It chips out of 45F cold storage, but has a low specific gravity. It has been transformed with the starch gene to raise the specific gravity. These transgenic lines will be field-tested in year 2000. MSE221-1 - a MSU tablestock selection. It has high yield potential as seen in the MSU and on- farm trials. General appearance is good, but it has a netted appearance similar to Superior. It has strong resistance to scab. MSE228-1 - a MSU tablestock selection. It has high yield potential as seen in the MSU trial and on-farm trials. It has a medium vine maturity, excellent internal quality and intermediate scab tolerance. MSE246-5 - a MSU chip-processing selection. It produces round tubers, has some scab tolerance along with reduced susceptibility to late blight. It also chip-processes from 45 F cold storage and has a very high specific gravity. In the 1999 on-farm trials, despite average yield potential, the chip quality was better than many of the other lines. It is a candidate for the CHIPS2002 program. MSF099-3 - a MSU chip-processing selection. It has high specific gravity, smooth attractive tubers, excellent chip quality and will chip-process from 45 F cold storage. It yielded well on the on-far trials, but the large tubers tended to elongate. It is also scab susceptible. This line is in the CHIPS2001 program. MSF313-3 - a MSU tablestock and chip-processing selection. It has a medium vine maturity, , above average yield potential. The tubers have few defects and the shape is smooth and round with a bright appearance. It will chip-process out of the field and from storage. MSG227-2 - a MSU chip-processing selection with strong scab resistance. It has a high specific gravity, excellent chip quality and cold-chipping potential. The tubers are smooth-shaped with a flattened round appearance that is attractive. This line is a candidate for CHIPS2002. MSG274-3 - a MSU tablestock selection. It has strong late blight resistance to US8, but susceptible to scab. The line has high yield potential and a very high tuber set that can lead to a high percentage of B-size tubers. The tubers are oval with an attractive smooth shape and a bright skin. It has chipped out of the field and is in the CHDPS2001 program. MSNT-1 - an MSU chip-processing selection. It has above average yield potential, excellent chip quality and strong resistance to scab. Yield was below average in the MSU trial. It was in the 1998 and 1999 SFA trials along with the on-farm trials. It performed well in Ontario trials in 1999. It is in the CHIPS2001 program. NY112 - a Cornell University chip-processing selection. It has high yield potential and was the top yielder in the 1998 SFA trials. The specific gravity is in the range of 1.080 or lower. Blackspot bruise has been observed in simulated bruise tests in the past two years. Chipeta - a chip-processing variety released in 1993. It is a high yielding line with a moderate specific gravity. The vine is strong. Scab resistance is intermediate. B. Long Varieties Three varieties and seven breeding lines were tested in 1999. Russet Burbank and Russet Norkotah were grown as check varieties. The trial was dug at 122 days from planting and results are shown in Table 3. Early die was present in the trial resulting in early vine senescence and low yield. All specific gravity levels were below normal with Russet Burbank at 1.069. Within the 10 entries MSG088-6RUS, MSE202-3RUS and MSH026-3RUS produced the highest yields. Variety Characteristics A7961-1 - is an USDA-Aberdeen entry with good performance. It has uniform appearance, heavier russeting than Russet Burbank and minimal internal defects. It can be used for frozen- processing. It will be named in the Northwest. Innovator - a European selection that has attractive russetting and produces excellent fry color, but has a low specific gravity. MSB106-7 - a MSU tablestock selection. It has high yield potential as seen in the on-farm trials, but performed poorly at MSU. Tubers are oblong-long with a light netting. In 1999 it was the top yielder in Nebraska. MSE192-8RUS - a MSU tablestock selection. The tubers have an attractive russeting and shape. The yield in on-farm trials have been disappointing, but performed well in some on-farm trials in 1999. The vine is small which may make this line uncompetitive in small plot trials. MSE202-3RUS - a MSU dual purpose russet selection. It has a medium maturity and above average yield potential. Its specific gravity is equivalent to Russet Burbank and the tubers are long with an attractive russet skin. Scab resistance is also high. C. North Central Regional Trial The North Central Trial is conducted in a wide range of environments (10 states) to provide adaptability data for the release of new varieties from North Dakota, Minnesota, Wisconsin, Michigan and Canada. Nineteen breeding lines and seven varieties were tested in Michigan. The results are presented in Table 4. Like all the other trials, potato early die influenced the trials, making it hard to judge the yield potential of these lines. The range of yields was wide and the specific gravity was average. The MSU selections MSE018-1 and MSB107-1 performed well. The line ND2470-27 performed well as a chip-processing selection. The MSU line MSA091-1 performed well in the Nebraska trials, despite low yields at MSU. The red-skinned North Dakota line, ND5084-3R, had high yield and excellent red color, but it has a very late maturity and severely sticky stolons. D. European/Yellow Trial Fourteen European varieties and advanced selections were tested along with six yellow-fleshed MSU seedlings. Yukon Gold and Saginaw Gold were used as checks. The results are summarized in Table 5. Typically, most of the European selections and varieties tend to be late to very-late in maturity, but the vines senesced early and we observed a high percentage of 'B' size tubers. The yields were below average and varied considerably. The best performing lines in 1999 were Columbo, MSE048-2Y and Sierra. Victoria and Gigant had severely late vine senescence. Bolestra shows chip-processing potential, while Lady Claire made excellent chips despite low yields. Yukon Gold, MSE048-2Y and MSG145-1Y had the best percentage of marketable tubers. Hollow heart was noted in the oversize tubers of MSG145-1Y and MSE048-2Y. The selection MSE040- 6RY is a yellow-fleshed selection with a red skin color equivalent to Chieftain. MSA097-1Y performed below average compare to other years, but should be noted for its scab resistance. E. Adaptation Trial Nine varieties and 37 advanced breeding lines were evaluated in the Adaptation trial (Table 6). The trial was harvested after 141 days, but potato early die led to early vine senescence in late August in most cases. The highest yielding lines were MSE028-1 (tablestock), MSE273-8 (chip- processing) and MSG124-8P (blue-fleshed chip-processor). MSE028-1 has a bright skin and scab tolerance, while MSE273-8 has susceptibility to scab. IdaRose is a late maturing, red-skinned variety with promise. MSH333-3 and MSH031-5 show promise and note that MSH031-5 has an attractive bright skin and smooth appearance along with chip-processing potential. Other lines worth noting include Michigan Purple (attractive purple skin and white flesh), MSG147-3P (blue- fleshed chip-processor), MSG004-3 (bruise resistant tablestock), and MSG015-C (scab-resistant chip-processor). F. Preliminary Trial The Preliminary trial, harvested at 122 days, is the first replicated trial for evaluated new advanced selections from the MSU potato breeding program. Potato early die was a factor in this trial too. Sixty advanced selections were tested, but some were dropped from Table 7 because of poor tuber qualities noted at harvest and grading. MSF373-8 shows the highest yield potential with a high percentage of oversize tubers. It has excellent internal quality, some scab tolerance and will chip-process, but has medium-deep eyes. Other promising chip-processing lines include MSI172- 7, MSH017-C, MSI103-5, MSI002-3, MSI117-1 and MSH067-3. MSI03-5 and MSH067-3 are both scab tolerant too. Other tablestock selections with promise include MSI053-2, MSI005-20Y, MSG106-5 and MS178-8. G. Potato Scab Evaluation Each year a replicated field trial at the MSU Soils Farm is conducted to assess resistance to common and pitted scab. The varieties are ranked on a 1-5 scale 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 8A categorizes many of the varieties and advanced selections tested in 1999 at the MSU Soils Farm Scab Nursery. This disease trial is a severe test. The varieties and lines are placed into five arbitrary categories based upon scab infection level and lesion severity. A rating of 1.0 indicates zero to a trace amount of infection. A moderate resistance (1.2 - 1.8) correlates with <10% infection. These two categories are good levels of scab tolerance. Susceptible lines have greater than 25% infection with pitted lesions. Scores of 4.0 or greater are found on lines with >50% infection and severe pitted lesions. The check varieties Russet Burbank, Superior, Onaway, Red Pontiac, Yukon Gold, Atlantic and Snowden can be used as references (bolded in Table 8). Scab results are also found in the Trial Summaries (Tables 2,3,4, 5, 6 and 7). Table 8B summarizes the 1997-9 scab trial results for the varieties and lines that have been tested at least two years in the past four years. These multi-year results give a more stable rating score for the clones tested in these trials. H. Late Blight Trial In 1999 a late blight trial was conducted at the Muck Soils Research Farm. Over 170 entries were evaluated in replicated plots. The field was inoculated late-July and ratings were taken during August. Most lines were highly susceptible to the US-8 genotype of late blight. Lines with the least infection were LBR8, LBR9, AWN86514-1, B0718-3, NY121 (Q237-25), MSG274-3 and Torridon (a Scottish variety). The good agronomic and tuber qualities of MSG274-3 make this selection the strongest late blight resistant line a candidate for commercialization. Lines with reduced susceptibility to late blight are Umatilla Russet, Legend Russet (C0083008-1), B9922-11, MSG124-8P and MSA091-1. Foliar susceptibility of all the lines tested against the US-8 genotype of late blight is summarized in Table 9. I. Blackspot Susceptibility Increased evaluations of advanced seedlings and new varieties for their susceptibility to blackspot bruising has been implemented in the variety evaluation program. Check samples of 25 tubers were collected (a composite of 4 reps) from each cultivar at the time of grading. A second 25 tuber sample was similarly collected, placed in 50F storage overnight and then was placed in a hexagon plywood drum and tumbled 10 times to provide a simulated bruise. Both 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 Tables 10A and 10B. Table 10A summarizes the data for the samples receiving the simulated bruise and Table 10B, the check samples. 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. We are also hoping the uniform tuber temperature prior to bruising may help reduce variability observed in previous years. These results become more meaningful when evaluated over 3 years which reflects different growing seasons and harvest conditions. The data indicates that bruise levels were average compared to other years. The most bruise resistant lines were MSE228-1, A7961-1, MSE192- 8RUS, ND3574-5R, MSG145-1Y, MSG147-3P, MSI178-8 and MSF015-1. J. Post-harvest Disease Evaluation: Fusarium Dry Rot As part of the postharvest evaluation, resistance to Fusarium sambucinum (fusarium dry rot) was assessed by inoculating 8 whole tubers post-harvest from each line in the variety trials. The tubers were held at 20°C for approximately three weeks and then scored for dry rot infection depth and width. These data are summarized in Table 11. The clones in this table are ranked according to infection depth. Infection levels within a clone can vary as seen by the multiple tests of the check varieties. Snowden, which has tolerance to fusarium, had infections from 3.4-6.0 mm in depth. Russet Burbank infections ranged from 4.5- 5.9 mm, while Atlantic infections were from 6.3-16.6 mm. No clones showed immunity to dry rot, however, some lines show tolerance at levels equivalent to Russet Norkotah, Snowden and Superior. Some key lines with identified tolerance are MSH106-2, MSG004-3, P83-11-5, MSH031-5, MSE018-1, NY112, MSE202-3RUS, MSG227-2, MSF313-3, MSG145-1Y. ROUND WHITES: EARLY HARVEST MONTCALM RESEARCH FARM AUGUST 9, 1999 (98 DAYS) CWT/A CWT/A US#1 TOTAL Percent of Total 1 US#1 Bs As Percent of Total 1 Percent of Total 1 Percent of Total 1 OV PO Percent of Total 1 SP GR SFA† MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS TUBER QUALITY 2 HH TUBER QUALITY 2 VD TUBER QUALITY 2 IBS TUBER QUALITY 2 BC TOTAL CUT 3-YR AVG US#1 CWT/A 332 315 272 267 262 235 231 230 230 229 222 220 218 212 200 197 190 183 183 180 174 172 168 164 144 124 89 371 391 301 319 310 295 265 298 324 300 303 263 343 270 267 262 284 274 254 252 264 219 239 283 272 198 89 81 90 84 85 80 87 77 71 76 73 84 64 78 75 75 67 67 72 71 66 78 70 58 53 62 26 11 19 8 13 14 20 11 21 29 13 24 14 36 21 24 23 30 31 27 28 31 20 28 40 47 36 85 77 83 73 78 79 82 76 70 71 73 81 64 70 75 72 66 65 72 70 65 78 70 58 53 62 26 5 3 7 11 6 1 5 1 1 5 1 2 0 8 0 3 0 2 0 1 1 0 0 0 0 0 0 73 0 0 2 3 1 1 2 2 0 11 3 2 0 0 0 1 4 2 1 1 2 1 2 2 0 1 1 1.083 1.087 1.083 1.091 1.081 1.074 1.075 1.070 1.080 1.071 1.064 1.075 1.084 1.075 1.088 1.066 1.084 1.092 1.093 1.084 1.085 1.070 1.082 1.081 1.087 1.090 1.081 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 5 2 0 12 2 1 3 0 0 0 0 0 0 0 0 0 0 2 0 1 2 1 0 0 0 0 1 3 11 0 1 0 0 0 0 1 4 0 2 0 0 1 0 0 0 7 1 9 3 1 1 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1.0 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 - - 435* 256 - 259 - - - 306* 274 222 151* 177 270* 198 267* - 295* 223* 191 - - 184 176 152 160* 40 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1.081 0.003 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 340 287 33 2 QUALITY HH: HOLLOW HEART BC: BROWN CENTER VD: VASCULAR DISCOLORATION IBS: INTERNAL BROWN SPOT OUT OF THE FIELD † SNACK FOOD ASSOCIATION CHIP SCORE RATINGS: 1 - 5 1: EXCELLENT 5: POOR TABLE 1 LINE NY112 MSE018-1 NY120 ATLANTIC MSF313-3 MSF014-9 CHIPETA MSG050-2 MSE228-1 MSE221-1 ONAWAY REBA MSE228-11 NY115 MSNT-1 MSE149-5Y MSG227-2 MSF099-3 MSE246-5 SNOWDEN P83-11-5 SUPERIOR MSA091-1 MSB076-2 MSC148-A MSE250-2 MSG274-3 MEAN LSD 0.05 209 34 1 SIZE_ B: <2" A: 2-3.25" OV: >3.25" PO: PICKOUTS * TWO-YEAR AVERAGE PLANTED MAY 3, 1999 TABLE 2 LINE MSE018-1 NY112 ATLANTIC MSE228-1 MSF313-3 CHIPETA NY120 MSG050-2 MSE228-11 REBA MSF014-9 SNOWDEN ONAWAY NY115 MSE149-5Y MSE221-1 MSG227-2 MSF099-3 SUPERIOR MSNT-1 MSE246-5 P83-11-5 MSA091-1 MSG274-3 MSB076-2 MSE250-2 MSC148-A MEAN LSD 0.05 CWT/A US#1 386 385 324 321 318 296 284 283 279 254 253 247 245 244 240 240 236 230 228 228 218 201 197 178 170 159 148 252 46 ROUND WHITES: LATE HARVEST MONTCALM RESEARCH FARM SEPTEMBER 20, 1999 (140 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A PERCENT OF TOTAL 1 TOTAL PERCENT OF TOTAL 1 US#1 Bs PERCENT OF TOTAL 1 As PERCENT OF TOTAL 1 OV PO PERCENT OF TOTAL 1 SP GR sfa† TUBER QUALITY 2 HH TUBER QUALITY 2 VD TUBER QUALITY 2 IBS TUBER QUALITY 2 BC TOTAL CUT SCAB 3 MAT 4 3-YR AVG US#1 CWT/A 449 422 374 405 370 353 312 332 387 301 311 314 315 310 298 295 321 314 277 296 285 313 273 409 283 238 264 327 42 86 91 87 79 86 84 91 85 72 85 81 79 78 79 81 82 73 73 82 77 76 64 72 44 60 67 56 13 9 11 19 12 10 6 14 27 14 18 21 17 21 18 9 23 25 16 22 22 32 22 55 39 29 43 81 80 76 75 75 75 81 78 71 78 77 74 77 74 78 73 72 72 81 75 74 64 72 43 60 67 56 6 12 11 4 11 9 11 7 1 6 4 4 1 5 3 9 1 1 1 2 2 1 0 0 0 0 0 1 0 3 2 2 6 3 1 1 1 0 1 6 1 1 10 3 2 2 1 1 4 6 1 1 4 1 1.089 1.079 1.090 1.070 1.077 1.073 1.078 1.069 1.082 1.073 1.072 1.080 1.062 1.074 1.062 1.067 1.080 1.086 1.069 1.084 1.090 1.082 1.080 1.079 1.078 1.090 1.084 2.0 1.5 1.5 - 1.5 1.5 2.0 - 2.0 1.0 1.5 1.5 - 1.5 1.5 - 1.5 1.5 - 1.0 1.0 1.0 1.0 1.5 2.0 1.5 1.0 8 16 5 0 0 5 0 0 0 2 0 0 0 0 0 0 1 0 0 1 1 0 0 0 0 3 0 6 2 3 4 5 6 22 2 2 5 0 8 9 2 0 3 0 1 12 1 9 5 6 0 0 0 0 0 1 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 3.0 1.5 3.0 3.0 2.7 2.3 1.3 2.0 3.0 2.0 3.0 3.0 1.2 1.5 2.0 1.2 1.1 2.7 1.0 1.5 2.0 1.7 1.0 3.5 1.5 2.3 2.5 5.0 3.5 2.5 3.0 3.5 4.5 3.0 2.0 4.0 3.0 3.0 3.0 1.5 2.0 2.0 1.5 3.5 3.0 1.0 3.0 3.0 2.5 2.5 4.0 1.5 4.5 1.0 363 448* 312 339* - - - - 245 219* 241 236 301* 304* 274 - - 307* - 211 262* - 221 - 193 194* 166 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1.078 empty table cell 0.002 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1 SIZE B: <2" A: 2-3.25” OV: >3.25" PO: PICKOUTS 2 QualiTY HH: HOLLOW HEART BC: BROWN CENTER VD: VASCULAR DISCOLORATION IBS: INTERNAL BROWN SPOT 3 SCAB DISEASE RATING (FROM MSU SCAB NURSERY) 1: NO INFECTION 3: INTERMEDIATE 5: HIGHLY SUSCEPTABLE 4 MATURITY RATING RATINGS: 1 - 5 1: EARLY 5: LATE * TWO-YEAR AVERAGE PLANTED MAY 3, 1999 †SNACK FOOD ASSOCIATION CHIP SCORE OUT OF THE FIELD RATINGS: 1 - 5 1: EXCELLENT 5: POOR TABLE 3 LINE MSG088-6RUS MSE202-3RUS MSH026-3RUS MSB106-7 INNOVATOR A7961-1 ND4093-4RUS MSE192-8RUS RUSSET NORKOTAH RUSSET BURBANK MEAN LSD 0.05 1 SIZE B: <4oz. A: 4-10 oz. OV: >10oz. PO: PICKOUTS LONG WHITES and RUSSETS MONTCALM RESEARCH FARM SEPTEMBER 2, 1999 (122 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS cwT/A CWT/A TOTAL PERCENT OF TOTAL 1 PERCENT OF TOTAL 1 As PERCENT OF TOTAL 1 US#1 Bs US#1 PERCENT OF TOTAL 1 PO SP GR TUBER QUALITY 2 HH TUBER QUALITY 2 VD TUBER QUALITY 2 IBS TUBER QUALITY 2 BC TOTAL CUT SCAB3 MAT4 3-YR AVG US#1 CWT/A PERCENT OF TOTAL 1 OV 276 206 204 197 173 141 116 102 99 83 160 49 369 295 320 311 288 267 245 255 223 242 282 47 75 70 64 63 60 53 47 40 44 34 22 27 36 32 35 45 52 56 55 59 69 65 62 60 56 52 47 38 44 34 6 5 1 4 4 1 1 2 1 0 3 3 1 5 5 3 1 4 1 7 1.068 1.074 1.071 1.060 1.069 1.075 1.068 1.065 1.064 1.069 0 1 1 0 0 5 2 0 0 0 5 2 2 3 1 7 0 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 40 40 40 40 40 30 30 20 10 10 2.0 1.2 1.5 1.3 3.0 1.0 1.3 1.2 2.0 1.0 3.5 3.5 2.0 1.5 3.0 3.5 1.5 1.5 1.0 2.5 343* 173* - 175 232* 209 - 164* 153* 157 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1.068 empty table cell 0.002 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell HH: HOLLOW HEART 2 QUALITY BC: BROWN CENTER VD: VASCULAR DISCOLORATION IBS: INTERNAL BROWN SPOT (FROM MSU SCAB NURSERY) 3 SCAB DISEASE RATING 1: NO INFECTION 3: INTERMEDIATE 5: HIGHLY SUSCEPTABLE 4 MATURITY RATING RATINGS: 1 - 5 1: EARLY 5: LATE *TWO-YEAR AVERAGE PLANTED MAY 3, 1999 TABLE4 MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A CWT/A TOTAL LINE US#1 422 371 359 351 346 326 318 280 261 255 255 250 236 218 215 212 205 196 183 161 151 146 129 126 99 62 236 50 ND5084-3R SNOWDEN RED PONTIAC ATLANTIC MSE018-1 ND2470-27 MSB107-1 FV8957-10 W1148R NORLAND ND3574-5R MN16966 MN17922 MSE263-10 MSA091-1 W1355-1 WIS75-30 NORVALLEY MN18713 FV9649-6 ND4093-4RUSS W1348RUS RUSSET BURBANK ND2937-3 RUSSET NORKOTAH MN18153 MEAN LSD 0.05 1 size_ B: <2” A: 2-3.25” OV: >3.25” PO: PICKOUTS PLANTED MAY 3, 1999 NORTH CENTRAL REGIONAL TRIAL MONTCALM RESEARCH FARM SEPTEMBER 7,1999 (127 DAYS) PERCENT OF TOTAL 1 PERCENT OF TOTAL 1 PERCENT OF TOTAL 1 PERCENT OF TOTAL 1 US#1 Bs As OV PO PERCENT OF TOTAL 1 SP GR SFA† TUBER QUALITY 2 HH TUBER QUALITY 2 VD TUBER QUALITY 2 IBS TUBER QUALITY 2 BC TOTAL CUT SCAB3 MAT4 469 411 421 400 425 399 352 332 323 325 322 375 261 271 294 315 337 323 305 280 295 280 261 286 208 168 325 49 90 90 85 88 82 82 90 84 81 79 79 67 90 80 73 67 61 61 60 57 51 52 50 44 48 37 7 9 13 11 16 15 7 12 18 19 20 30 8 19 22 32 37 36 38 40 47 45 40 39 52 62 53 87 82 83 78 79 84 82 79 78 79 63 74 80 73 67 61 60 55 52 49 52 49 44 45 36 37 3 4 4 4 2 6 3 2 1 0 4 16 0 0 0 0 1 5 6 2 0 0 0 3 1 3 1 2 1 3 3 3 3 1 2 1 3 2 1 5 0 2 4 2 2 2 2 10 16 0 1 1.056 1.087 1.060 1.091 1.084 1.077 1.074 1.070 1.069 1.056 1.053 1.078 1.057 1.073 1.079 1.080 1.074 1.072 1.082 1.062 1.068 1.073 1.068 1.060 1.063 1.062 2.5 1.5 3.0 1.5 1.5 1.0 1.5 1.0 2.0 2.5 3.0 1.5 3.0 1.5 2.0 1.0 1.5 1.5 1.5 2.5 2.5 1.5 2.0 2.5 2.0 2.0 1 2 1 11 1 0 0 4 0 1 0 0 0 0 0 0 0 0 0 2 3 3 0 0 1 0 5 26 8 6 12 14 9 15 12 7 4 9 15 8 7 7 4 2 8 0 0 1 4 0 1 0 1 0 0 1 0 0 2 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 30 30 30 10 0 1.8 3.0 3.8 3.0 3.0 2.5 1.5 4.0 1.3 - 2.0 2.5 - 1.0 2.8 2.0 - 1.0 3.0 1.3 1.0 1.0 4.0 2.0 - - 4.0 4.5 4.0 3.5 5.0 3.0 4.0 3.0 2.5 1.0 1.0 4.0 3.0 2.0 3.0 3.5 2.0 2.5 3.0 2.0 1.0 3.0 3.5 1.0 1.0 1.5 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1.070 empty table cell 0.003 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 2 QUALITY HH: HOLLOW HEART BC: BROWN CENTER VD: VASCULAR DISCOLORATION IBS: INTERNAL BROWN SPOT 3 SCAB DISEASE RATING (FROM MSU SCAB NURSERY) 1: NO INFECTION 3: INTERMEDIATE 5: HIGHLY SUSCEPTABLE 4 MATURITY RATING RATINGS: 1-5 1: EARLY 5: LATE † SNACK FOOD ASSOCIATION CHIP SCORE OUT OF THE FIELD RATINGS: 1 - 5 1: EXCELLENT 5: POOR TABLE 5 LINE COLUMBO ACCENT MSE048-2Y SIERRA MSE222-5Y GIGANT YUKON GOLD MSG145-1Y BOLESTRA MSE226-4Y ELOGE VICTORIA TORRIDON SAGINAW GOLD ACCORD MSA097-1Y MSE040-6RY APELL MATILDA ZAREVO SW93107 LADY CLAIRE MEAN LSD 0.05 1 SIZE B: <2" A: 2-3.25” OV: > 3.25” PO: PICKOUTS YELLOW FLESH and EUROPEAN TRIAL MONTCALM RESEARCH FARM SEPTEMBER 13, 1999 (133 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS CWT/A CWT/A TOTAL US#1 PERCENT OF TOTAL 1 PERCENT OF TOTAL 1 Bs PERCENT OF TOTAL 1 As PERCENT OF TOTAL 1 PERCENT OF TOTAL 1 OV US#1 PO SP GR SFA† TUBER QUALITY 2 HH TUBER QUALITY 2 VD TUBER QUALITY 2 IBS TUBER QUALITY 2 BC TOTAL CUT SCAB 3 MAT4 304 278 277 270 255 244 242 212 207 205 187 184 170 166 151 144 140 109 107 95 91 62 186 47 444 426 343 359 376 343 279 278 334 326 328 339 358 285 322 260 318 297 349 195 258 253 321 37 69 65 81 75 68 71 87 76 62 63 57 54 48 58 47 55 44 37 31 49 35 25 30 26 16 21 26 24 12 22 34 35 41 40 48 37 51 44 55 56 68 35 61 75 67 64 78 69 65 70 77 75 62 61 56 54 47 58 47 54 43 37 31 47 35 25 1 1 3 6 3 1 10 1 0 2 1 0 0 0 0 2 0 0 0 2 0 0 1 9 3 4 6 5 1 2 5 2 2 5 5 4 2 1 1 7 1 16 4 0 1.065 1.060 1.072 1.063 1.075 1.082 1.074 - 1.070 - 1.084 1.066 - 1.066 1.076 1.090 1.073 1.080 1.074 1.068 - 1.064 1.082 1.086 1.079 1.077 2.0 4.5 - 3.5 - - 1.0 3.0 - 1.5 - 2.0 2.5 3.0 - - 3.0 1.0 0 0 7 2 2 0 2 14 0 0 0 0 0 3 0 0 0 0 0 7 0 0 0 12 0 11 0 3 3 0 6 1 0 20 5 2 0 0 2 1 4 3 1 0 0 1 0 1 0 12 0 1 0 0 6 0 2 0 2 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 30 10 30 20 0 3.2 2.0 2.0 2.3 2.7 2.5 2.5 2.0 3.0 1.1 4.0 2.0 4.0 1.3 2.3 1.0 2.0 2.7 2.8 2.8 1.8 2.0 3.0 3.0 3.0 3.5 2.5 5.0 2.0 1.5 5.0 2.0 2.0 5.0 4.5 1.0 2.5 1.5 1.5 3.0 4.0 4.0 4.0 1.5 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1.074 empty table cell 0.003 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 2 QUALITY HH: HOLLOW HEART BC: BROWN CENTER VD: VASCULAR DISCOLORATION IBS: INTERNAL BROWN SPOT 3 SCAB DISEASE RATING (FROM MSU SCAB NURSERY) 1: NO INFECTION 3: INTERMEDIATE 5: HIGHLY SUSCEPTABLE 4 MATURITY RATING RATINGS: 1 - 5 1: EARLY 5: LATE PLANTED MAY 3, 1999 † SNACK FOOD ASSOCIATION CHIP SCORE OUT OF THE FIELD RATINGS: 1 - 5 1: EXCELLENT 5: POOR TABLE 6 LINE MSE028-1 MSE273-8 MSG124-8P IDA ROSE MSH333-3 MSH031-5 MSF001-2 MSG049-4 MSH041-1 ATLANTIC MSF060-6 MSH101-2 MICHIGAN PURPLE MSH106-2 MSG147-3P MSG004-3 MSG015-C ROCKET MSG007-1 ONAWAY SNOWDEN NAVAN MSH098-2 MSH018-5 MIDAS MSH217-1 SAXON MSH384-1Y MSI201-2PY MSF002-1 MSH123-5 MSG141-1 MSH094-8 MSH380-3Y MSH228-6 MSH015-2 SUPERIOR MSH095-4 MSH419-1 MSH321-1 MSF087-3RUS MSH120-1 MSH418-1 MSH370-3 MSH361-2 NY121 MEAN LSD 0.05 1 SIZE B: <2” A: 2-3.25" OV: >3.25” PO: PICKOUTS PLANTED MAY 3, 1999 ADAPTATION TRIAL MONTCALM RESEARCH FARM SEPTEMBER 21, 1999 (141 DAYS) MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS TUBER QUALITY 2 HH TUBER QUALITY 2 VD TUBER QUALITY 2 IBS TUBER QUALITY 2 BC TOTAL CUT SCAB3 MAT4 - CWT/A US #1 CWT/A TOTAL 388 363 362 338 328 322 309 307 306 303 298 293 288 279 278 268 264 259 256 254 248 243 241 237 234 234 229 227 225 224 222 220 219 215 212 205 200 199 185 166 164 153 147 145 102 74 244 55 470 409 381 377 376 401 363 341 377 359 345 342 344 328 340 307 364 358 316 324 317 327 316 397 403 309 330 336 385 285 289 291 298 287 270 285 247 256 253 311 319 281 234 232 266 233 326 53 OV SP GR SFA† PERCENT OF TOTAL1 PERCENT OF TOTAL1 PO 3 12 24 13 5 2 3 13 6 5 1 6 7 8 3 7 2 2 1 3 3 13 7 1 0 2 1 0 1 1 PERCENT OF TOTAL 1 US #1 83 89 95 90 87 80 85 90 81 84 86 86 84 85 82 87 73 73 81 78 78 74 76 60 58 76 69 67 58 78 77 75 74 75 79 72 81 78 69 53 51 54 63 63 38 32 empty table cell empty table cell PERCENT OF TOTAL1 PERCENT OF TOTAL 1 As Bs 14 80 10 77 4 71 9 77 10 82 19 79 14 82 5 77 15 75 13 79 14 85 14 80 16 77 15 77 17 79 12 81 27 71 25 71 18 80 19 75 21 76 22 61 10 70 38 59 23 58 23 73 29 69 30 67 39 58 22 78 23 73 4 23 75 23 73 23 74 19 75 18 70 18 79 19 74 29 67 42 53 47 50 43 54 36 62 32 60 58 38 68 32 empty table cell empty table cell 2 3 2 3 10 1 3 3 5 1 3 1 5 4 0 empty table cell empty table cell 0 6 13 1 0 0 0 6 5 6 0 1 0 2 0 0 0 2 0 0 1 18 0 0 0 6 1 0 0 0 4 1 1 1 3 0 1 5 4 2 0 1 0 0 1 1 0 3 0 2 1 4 14 2 19 2 2 3 3 0 1.079 1.073 2.0 1.071 2.0 1.070 - 1.077 2.0 1.081 1.5 1.070 1.5 1.069 - 1.070 1.0 1.088 1.0 1.084 2.0 1.078 2.0 1.071 - 1.093 1.5 1.066 1.5 1.066 - 1.079 1.5 1.074 - 1.094 1.0 1.063 - 1.080 1.5 1.082 2.5 1.085 1.5 1.088 1.0 1.081 1.5 1.086 1.5 1.057 - 1.080 3.0 1.073 - 1.070 2.0 1.083 1.5 1.089 1.5 1.080 1.0 1.084 2.0 1.076 1.5 1.088 1.5 1.071 - 1.077 1.0 1.087 1.5 1.079 2.0 1.080 - 1.080 2.0 1.092 1.5 1.076 1.0 1.086 2.0 1.077 - 1.078 empty table cell empty table cell empty table cell 0.003 empty table cell 0 1 2 2 0 0 3 2 1 3 0 2 1 0 0 empty table cell empty table cell 0 1 1 4 2 2 4 2 1 2 0 1 3 0 0 0 0 11 5 0 1 1 1 1 4 3 0 3 4 6 4 0 0 4 3 1 8 11 3 0 2 7 2 2 10 0 2 10 1 2 1 4 1 5 8 3 1 0 4 0 3 0 0 3 2 0 3 0 0 0 0 0 1 5 1 0 6 0 0 1 0 1 0 0 13 0 1 0 1 1 0 0 0 0 0 2 0 2 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 2 0 2 0 0 0 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 2 0 1 0 0 0 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 30 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 30 40 30 30 40 0 0 1.0 4.5 1.3 1.3 3.3 2.0 3.5 3.3 2.3 3.0 - 3.0 3.0 1.0 2.5 3.0 1.2 2.3 1.8 1.2 3.0 2.8 2.5 2.5 1.3 3.3 1.8 3.8 3.5 3.3 1.5 1.7 2.5 3.0 1.5 1.5 1.0 2.0 3.0 - 1.0 1.2 2.5 2.0 1.0 1.0 4.5 3.5 5.0 5.0 3.5 3.0 3.5 2.0 3.0 3.5 4.0 3.0 3.0 4.0 4.0 3.5 4.0 2.5 3.0 2.0 3.0 5.0 3.5 3.5 5.0 4.5 2.5 3.0 4.0 3.0 2.5 3.0 3.0 4.0 2.0 1.5 2.5 3.0 3.0 2.0 3.0 3.0 2.0 2.0 2.0 4.0 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cellempty table cell empty table cellempty table cell empty table cell empty table cell 4 MATURITY RATING RATINGS: 1-5 1: EARLY 5: LATE 2 QUALITY HH: HOLLOW HEART BC: BROWN CENTER VD: VASCULAR DISCOLORATION IBS: INTERNAL BROWN SPOT 3SCAB DISEASE RATING (FROM MSU SCAB NURSERY) 1: NO INFECTION 3: INTERMEDIATE 5: HIGHLY SUSCEPTABLE 1†SNACK FOOD ASSOCIATION CHIP SCORE OUT OF THE FIELD RATINGS: 1 - 5 1: EXCELLENT 5: POOR TABLE 7 PRELIMINARY TRIAL MONTCALM RESEARCH FARM SEPTEMBER 2, 1999 (122 DAYS) LINE CWT/A CWT/A TOTAL US#1 PERCENT OF TOTAL 1 PERCENT OF TOTAL 1 US#1 Bs PERCENT OF TOTAL 1 As PERCENT OF TOTAL 1 OV PO SP GR SFA† PERCENT OF TOTAL 1 TUBER QUALITY 2 HH TUBER QUALITY 2 VD MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS SCAB3 MAT4 TUBER QUALITY 2 IBS TUBER QUALITY 2 BC TOTAL CUT PEDIGREE MSF373-8 MSI172-7 MSI077-5 MSH017-C MSI103-5 MSI002-3 MSH063-A MSI117-1 MSI053-2 ATLANTIC MSH067-3 MSI005-20Y MSI050-4 MSG106-5 MSH013-A MSH306-B MSI178-8 MSI057-1 B1865-2 SNOWDEN MSI004-2Y MSI160-7 MSI223-6 MSI037-7 MSI055-5 MSI083-5 MSI039-8Y MSH360-1 MSI193-5 MSI234-6Y ONAWAY MSI085-10 MSI083-4 MSI060-3 MSF015-1 MSI026-2 MSI066-2 MSI082-3 MSI005-11Y MSI168-5 MSI004-3 MSI005-12Y MSF090-9 MSH009-A MSI168-2 MSI043-1 MSF382-2 MEAN LSD 0.05 401 392 363 351 333 320 316 315 311 309 308 306 304 302 299 297 292 289 281 279 275 275 272 269 262 260 257 250 250 250 245 244 242 238 232 227 227 223 205 203 202 195 192 186 180 165 151 267 72 424 435 398 381 409 380 392 370 340 374 335 403 393 341 374 353 343 391 345 346 344 352 371 331 366 330 327 288 289 360 338 320 299 315 284 335 369 302 308 327 309 316 267 298 255 311 244 342 66 95 90 91 92 82 84 81 85 91 83 92 76 77 88 80 84 85 74 82 81 80 78 73 81 72 79 78 87 87 69 72 76 81 75 82 68 61 74 67 62 65 62 72 62 71 53 62 5 8 8 7 16 15 18 11 8 14 6 23 22 11 15 12 14 24 14 19 19 21 25 18 26 21 17 13 13 30 25 24 18 24 15 29 38 26 29 38 33 37 23 35 27 45 38 73 80 82 84 79 82 79 79 87 79 77 74 76 73 80 84 84 74 76 77 80 78 72 75 72 78 77 87 84 69 72 76 81 72 81 68 61 73 67 62 65 62 69 62 70 53 62 22 11 9 8 3 2 1 6 5 4 15 2 2 16 0 1 1 0 6 4 0 0 1 6 0 1 2 0 3 0 0 0 0 3 1 0 0 1 0 0 0 0 3 0 1 0 0 1 1 0 1 3 1 1 4 0 4 2 1 1 1 5 4 1 2 4 1 1 1 2 1 2 0 4 0 1 1 2 0 2 1 3 3 0 0 4 0 1 2 5 2 2 2 0 1.083 1.071 1.076 1.085 1.079 1.082 1.074 1.080 1.077 1.089 1.085 1.073 1.083 1.067 1.076 1.094 1.072 1.080 1.069 1.083 1.072 1.088 1.090 1.082 1.080 1.080 1.073 1.087 1.075 1.082 1.064 1.089 1.077 1.068 1.066 1.074 1.081 1.086 1.071 1.083 1.076 1.069 1.072 1.075 1.084 1.085 1.065 1.5 1.5 3.5 1.5 1.0 1.0 1.0 1.5 2.5 1.0 1.5 2.5 1.0 2.5 1.5 1.5 2.5 1.0 2.0 1.0 1.5 1.0 2.0 1.0 1.0 1.5 1.0 1.0 1.0 1.0 4.0 1.0 2.0 2.0 2.0 1.0 2.0 1.0 3.0 2.0 2.0 2.5 1.5 1.0 1.0 1.0 1.0 0 1 0 1 0 3 0 0 0 2 4 0 1 3 0 3 3 5 0 1 0 0 0 1 0 1 0 2 1 0 0 1 0 6 0 0 0 0 0 0 1 0 0 0 0 0 0 0 2 1 3 0 0 1 5 0 0 3 1 0 1 3 6 2 1 1 4 3 0 2 4 0 1 0 2 0 1 6 6 1 2 0 1 1 4 0 0 0 0 1 4 2 2 2 0 0 0 0 3 0 1 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 STOBRAWA X NDO1496 20 MS702-80 X NY88 20 NORVALLEY X F191-9 20 C084-1 X W870 20 ATL X NOVACHIP E149-5Y X LEMHI 20 20 A091-1 XF134-1 20 C121-7 X C086-7 20 PIKE X ND860-2 20 BRODICK X E234-3 20 empty table cell 20 C127-3 X W877 20 A097-1Y X PENTA 20 BRODICK X C127-3 20 PRESTILE X L235-4 20 ATL X C135-2 20 ATL X F077-8 20 NY101 X CHALEUR 20 BRODICK XF090-1 20 empty table cell 20 empty table cell 20 A097-1Y X LEMHI 20 NDA2031 -2 X F077-8 20 20 B110-3 X NDO1496-1 20 BRODICK X E263-10 20 C135-5 X B0718-3 20 B116-1Y X YUKON 20 PIKE X F077-8 20 PRESTILE X YUKON 20 W870 X I. SUNSHINE 20 empty table cell 20 C135-5 X ND01496-1 20 C135-5 X B0718-3 20 BRODICK X LEMHI 20 PIKE X W877 20 B076-2 X C135-4 20 BZURA X NDO1496-1 20 C135-4 XNDO1496-1 20 A097-1Y X PENTA 20 NDO1496-1 X F134-1 20 A097-1Y X LEMHI 20 AO97-1Y X PENTA 20 PIKE X W870 20 AO91-1 X LEMHI 20 ND01496-1 X F134-1 20 B1254-1 X F191-9 20 PIKE X L234-5 1.7 4.3 4.0 3.0 1.0 4.3 2.0 1.0 2.0 3.0 1.8 1.8 2.5 2.3 2.0 2.7 1.7 4.0 3.7 3.0 1.0 3.0 3.0 3.8 4.5 - 2.8 3.3 2.0 2.5 1.2 4.7 - 1.0 1.3 2.8 1.5 4.0 3.5 3.3 1.5 2.0 1.3 2.0 4.0 2.0 2.4 5.0 4.0 4.0 2.5 4.5 2.0 3.0 3.0 3.0 3.0 2.5 3.0 3.0 2.0 1.5 3.0 3.5 3.0 4.0 3.0 3.5 3.5 4.5 3.0 2.5 3.5 3.0 3.5 3.5 1.5 1.0 4.0 3.0 3.0 1.5 4.0 2.5 3.0 3.0 2.0 3.0 2.5 2.5 3.0 3.5 2.5 3.0 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1.078 empty table cell 0.004 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1 SIZE B: <2" A: 2-3.25” OV: > 3.25" PO: PICKOUTS 2 QUALITY.. HH: HOLLOW HEART BC: BROWN CENTER VD: VASCULAR DISCOLORATION IBS: INTERNAL BROWN SPOT 3 scab disease rating (FROM MSU SCAB NURSERY) 1: NO INFECTION 3: INTERMEDIATE 5: HIGHLY SUSCEPTABLE 4 MATURITY RATING RATINGS: 1 - 5 1: EARLY 5: LATE PLANTED MAY 3, 1999 †SNACK FOOD ASSOCIATION CHIP SCORE OUT OF THE FIELD RATINGS: 1 - 5 1: EXCELLENT 5: POOR TABLE 8A 1999 SCAB DISEASE TRIAL SCAB NURSERY, EAST LANSING, MI MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS LINE RATING LINE RATING LINE RATING LINE RATING LINE RATING 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.5 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 1.7 1.7 1.8 1.8 1.8 1.8 1.8 1.8 ACCENT B0564-9 MSE040-6RY MSE048-2Y MSE149-5Y MSE246-5 MSG050-2 MSG088-6RUS MSG145-1Y MSH009-A MSH013-A MSH031-5 MSH063-A MSH095-2 MSH370-3 MSI005-12Y MSI043-1 MSI053-2 MSI065-2Y MSI193-5 LADY CLAIRE ND3574-5R RUSSET NORKOTAH REBA VICTORIA WIS75-30 ACCORD CHIPETA MSE250-2 MSG106-5 MSH041-1 ROCKET SIERRA MSF382-2 MSC148-A MSG147-3P empty table cellGIGANT empty table cellMSH018-1 empty table cellMSH094-8 empty table cellMSH098-2 empty table cellMSH418-1 empty table cellMSI032-6 empty table cellMSI050-4 empty table cellMSI234-6Y empty table cellMN16966 empty table cellND2470-27 empty table cellYUKON GOLD empty table cellAPELL empty table cellMSE222-5Y empty table cellMSF099-3 empty table cellMSF313-3 empty table cellMSH306-B empty table cellMSF059-1 empty table cellMSI026-2 empty table cellMSI039-8Y empty table cellMATILDA empty table cellNAVAN empty table cellW1355-1 empty table cellZAREVO 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.4 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.7 2.7 2.7 2.7 2.7 2.8 2.8 2.8 2.8 2.8 2.8 2.8 ATLANTIC BOLESTRA MSE018-1 MSE228-1 MSE228-11 MSF014-9 MSF019-11 MSF105-10 FV9649-6 MSG004-3 MSH017-C MSH101-2Y MSH380-3Y MSH419-1 MSI160-7 MSI222-9 MSI223-6 INNOVATOR MI PURPLE SNOWDEN COLUMBO MSF002-1 MSG049-4 MSH217-1 MSH333-3 MSH360-1 MSI168-5 W1313 MSF001-2 MSG274-3 MSI005-11Y MSI201-2PY empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.2 3.3 3.3 3.3 3.3 3.3 3.3 3.3 3.5 3.5 3.5 3.5 B1865-2 MSH384-1Y MSI037-7 RED PONTIAC ELOGE FV8957-10 MSI057-1 MSI077-5 MSI082-3 MSI168-2 ND2937-3 TORRIDON MSI002-3 MSI172-7 P88-6-19 MSE273-8 MSI055-5 MSI085-10 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell 3.7 3.8 3.8 3.8 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.3 4.3 4.3 4.5 4.5 4.7 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell MSA091-1 MSA097-1Y A7961-1 B0564-8 MSE028-1 MSF087-3 GEM RUSSET MSH106-2 MSH361-2 MSI004-2Y MSI060-3 MSI103-5 MSI117-1 MN18713RUS NY121 RUSSET BURBANK SUPERIOR W1348RUS MSE226-4Y MSG227-2 MSE192-8RUS MSE202-3RUS MSE221-1 MSG015-C MSH120-1 ONAWAY empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 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 1.1 1.1 1.2 1.2 1.2 1.2 1.2 1.2 MSB106-7 MSF015-1 MSF056-1 MSF090-9 MSG124-8P MSH356-A IDA ROSE MIDAS ND4093-4RUS NY120 SAGINAW GOLD W1148R AF1668-60 MSB076-2 MSB107-1 MSE230-6 MSH015-2 MSH026-3RUS MSH123-5 MSH228-6 MSI004-3 MSI066-2 MSNT-1 NY112 NY115 MSF373-8 empty table cellMSG141-1 empty table cellMSI178-8 empty table cellND2676-10 empty table cellP83-11-5 empty table cellMSG007-1 empty table cellMSH067-3 empty table cellMSI005-20Y empty table cellND5084-3R empty table cellSAXON empty table cellSW93107 empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell SCAB DISEASE RATING 1: PRACTICALLY NO INFECTION 2: LOW INFECTION 3: AVG. SUSCEPTIBILITY (i.e. ATLANTIC) 4: HIGH SUSCEPTIBILITY 5: SEVERE SUSCEPTIBILITY TABLE 8B MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS SCAB DISEASE TRIAL, THREE-YEAR AVERAGES SCAB NURSERY, EAST LANSING, MI 1997 1998 1999 LINE RATING RATING RATING AVG. LINE 1997 1998 1999 RATING RATING RATING AVG. MSE246-5 MSE250-2 MSF001-2 MSF019-11 MSF099-3 MSF313-3 MSF373-8 MSG050-2 MSG124-8P MSG227-2 MSNT-1 ND2676-10 ONAWAY RED PONTIAC RUSSET BURBANK RUSSET NORKOTAH SAGINAW GOLD SNOWDEN W1313 YUKON GOLD 1.4 3.2 2.0 2.8 2.5 1.8 3.0 2.0 1.5 1.0 1.0 1.5 1.0 2.6 1.0 1.8 1.5 2.5 3.0 3.0 1.0 4.0 4.0 3.3 3.7 2.7 2.3 4.0 1.7 1.0 1.8 1.5 1.5 3.3 1.0 2.0 2.0 3.5 2.7 2.7 2.0 2.3 3.5 3.0 2.7 2.7 1.7 2.0 1.3 1.1 1.5 1.7 1.2 3.8 1.0 2.0 1.3 3.0 3.3 2.5 1.5 3.2 3.2 3.0 3.0 2.4 2.3 2.7 1.5 1.0 1.4 1.6 1.2 3.2 1.0 1.9 1.6 3.0 3.0 2.7 A7961-1 ATLANTIC MATILDA MSA091-1 MSA097-1Y MSB076-2 MSB106-7 MSB107-1 MSC148-A MSE018-1 MSE048-2Y MSE149-5Y MSE192-8RUS MSE202-3RUS MSE221-1 MSE222-5Y MSE226-4Y MSE228-1 MSE228-11 MSE230-6 1.0 3.3 2.3 1.8 1.7 1.8 1.3 1.8 2.4 2.6 2.1 2.0 1.3 1.0 1.0 3.0 1.9 2.7 1.5 1.5 1.0 3.3 2.5 1.5 2.0 1.2 2.3 1.0 3.3 3.0 1.0 1.8 1.0 - 1.5 2.0 2.3 2.8 3.2 2.3 1.0 3.0 2.8 1.0 1.0 1.5 1.3 1.5 2.5 3.0 2.0 2.0 1.2 1.2 1.2 2.7 1.1 3.0 3.0 1.5 1.0 3.2 2.5 1.4 1.6 1.5 1.6 1.4 2.7 2.9 1.7 1.9 1.2 1.1 1.2 2.6 1.8 2.8 2.6 1.8 SCAB DISEASE RATING 1: PRACTICALLY NO INFECTION 2: LOW INFECTION 3: AVG. SUSCEPTIBILITY (i.e. ATLANTIC) 4: HIGH SUSCEPTIBILITY 5: SEVERE SUSCEPTIBILITY TABLE 9 LATE BLIGHT VARIETY TRIAL MUCK SOILS RESEARCH FARM MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS Inoculated July 22, 1999 Rating based on a 28-day evaluation period RAUDPC Max = 1.000 LINE RAUDPC1 LSMEAN LINE RAUDPC LSMEAN LBR8 LBR9 MSG274-3 B0767-2 Q237-25 AWN86514-2 TORRIDON ROBIJN B0718-3 B0288-17 A90586-11 Bl865-2 ND6947B-15 LBR7 C086218-2 C0083008-1 DORITA ZAREVO NY121 B9922-11 A082611-7 LBR2 RUSSET NORKOTAH LBR5 ND6948B-12 W91-9459 ND02438-7R RED LASODA LBR3 MSG124-8P RUSSET BURBANK 2 SNOWDEN PIKE Ranger Russet 0.0336 0.0369 0.0377 0.0379 0.0452 0.0522 0.0696 0.0717 0.0742 0.0788 0.0866 0.0942 0.0957 0.1070 0.1265 0.1304 0.1427 0.1529 0.1618 0.1669 0.1673 0.1682 0.1753 0.1764 0.1772 0.1798 0.1810 0.1824 0.1836 0.1854 0.1930 0.1933 0.1959 0.2052 LBR1R2R3R4 SHEPODY NAVAN MIDAS LBR4 MSH120-1 NORDONNA NORVALLEY ND69488-5RUS GOLDRUSH GIGANT CHIPETA ACCORD BOLESTRA COLUMBO SIERRA ATLANTIC YUKON GOLD VICTORIA SAXON SUPERIOR ELOGE APELL ACCENT RED PONTIAC IDA ROSE LADY CLAIRE GEM RUSSET RED NORLAND ROCKET SAGINAW GOLD ONAWAY REBA W1355-1 0.2064 0.2066 0.2157 0.2189 0.2195 0.2257 0.2258 0.2315 0.2319 0.2345 0.2366 0.2377 0.2381 0.2397 0.2419 0.2433 0.2434 0.2445 0.2457 0.2472 0.2529 0.2564 0.2620 0.2622 0.2779 0.2781 0.2916 0.2938 0.2940 0.2962 0.2986 0.3076 0.3126 0.6101 LSD0.05 = 0.0837 1 Ratings indicate the RAUDPC (Relative Area Under the Disease Progress Curve) over the entire plot. 2 170 varieties and breeding lines were tested in all. For brevity purposes, only selected varieties and breeding lines with a RAUDPC value greater than Russet Burbank are listed. PERCENT (%) AVERAGE ROUND WHITES: LATE HARVEST SPOTS/TUBER ROUND WHITES: LATE HARVEST TABLE 10A MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS 1999 BLACKSPOT BRUISE SUSCEPTIBILITY TEST SIMULATED BRUISE SAMPLES* NUMBER OF SPOTS PER TUBER 1 3 4 NUMBER OF SPOTS PER TUBER 2 NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER BRUISE NUMBER OF SPOTS PER TUBER 0 NUMBER OF SPOTS PER TUBER 5+ empty table cell empty table cell empty table cell empty table cell empty table cell 1 empty table cell 3 empty table cell 3 empty table cell ROUND WHITES: LATE HARVEST empty table cell empty table cell empty table cell empty table cell empty table cell FREE ROUND WHITES: LATE HARVEST empty table cell empty table cell empty table cell empty table cell empty table cell 1 empty table cell VARIETY ROUND WHITES: LATE HARVESTROUND WHITES: LATE HARVESTROUND WHITES: LATE HARVESTROUND WHITES: LATE HARVEST MSE228-1 MSF014-9 MSE149-5Y MSE228-11 CHIPETA ONAWAY MSG227-2 NY115 SUPERIOR MSF099-3 P83-11-5 MSE246-5 MSC148-A MSE221-1 SNOWDEN MSG050-2 MSB076-2 MSG274-3 REBA MSA091-1 MSF313-3 MSE250-2 NY112 ATLANTIC NY120 MSE018-1 MSNT-1 ROUND WHITES: LATE HARVEST empty table cell25 1 empty table cell25 empty table cell empty table cell24 1 empty table cell25 2 empty table cell24 1 empty table cell20 1 empty table cell24 1 empty table cell23 2 empty table cell23 3 empty table cell27 6 empty table cell24 2 empty table cell26 3 empty table cell24 7 empty table cell25 8 empty table cell 5 21 empty table cell24 4 empty table cell23 6 empty table cell24 8 empty table cell 6 21 empty table cell23 6 3 26 empty table cell25 9 4 25 5 25 3 25 empty table cell24 8 10 25 LONG WHITES and RUSSETS TOTAL TUBERS ROUND WHITES: LATE HARVEST 0.240 0.280 0.292 0.360 0.417 0.450 0.458 0.522 0.565 0.704 0.958 0.962 1.000 1.120 1.143 1.167 1.261 1.292 1.381 1.435 1.500 1.560 1.760 1.960 1.960 2.250 2.480 2 empty table cell 1 3 empty table cell 4 empty table cell 3 empty table cell 4 empty table cell 3 2 3 8 empty table cell 3 6 10 6 80 72 75 72 63 70 71 57 57 59 38 38 42 36 33 25 35 29 29 22 31 16 20 20 16 4 0 20 18 18 18 15 14 17 13 13 16 9 10 10 9 7 6 8 7 6 5 8 4 5 5 4 1 4 7 5 5 8 4 5 8 7 4 10 10 6 6 7 11 5 6 5 8 9 8 7 7 8 4 5 empty table cell empty table cell 1 2 1 2 3 1 1 2 1 3 1 3 1 1 1 LONG WHITES and RUSSETS LONG WHITES and RUSSETS LONG WHITES and RUSSETS A7961-1 24 RUSSET NORKOTAH 23 MSE192-8RUS 19 1 2 2 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell25 empty table cell25 empty table cell21 96 92 90 0.040 0.080 0.095 LONG WHITES and RUSSETS LONG WHITES and RUSSETS LONG WHITES and RUSSETS LONG WHITES and RUSSETS LONG WHITES and RUSSETS LONG WHITES and RUSSETS * A-size tuber samples were collected at harvest, held at 50 F at least 12 hours, and placed in a six-sided plywood drum and rotated ten times to produce simulated bruising. Samples were abrasive-peeled and scored on October 20, 1999. The table is presented in descending order of average number of spots per tuber. NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER VARIETY RUSSET BURBANK MSH026-RUS MSE202-3RUS ND4093-4RUS INNOVATOR GEM RUSSET MSG088-6RUS MSB106-7 NUMBER OF SPOTS PER TUBER 0 18 19 13 10 14 10 10 4 1 5 6 12 12 6 7 6 9 PERCENT (%) AVERAGE SPOTS/TUBER 3 2 4 empty table cell empty table cell empty table cell NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER 5+ empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell TOTAL TUBERS empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell NORTH CENTRAL REGIONAL TRIAL BRUISE FREE 78 76 52 42 52 43 43 16 NORTH CENTRAL REGIONAL TRIAL NORTH CENTRAL REGIONAL TRIAL 0.217 0.240 0.480 0.667 0.741 0.870 1.000 1.600 23 25 25 24 27 23 23 25 1 3 3 2 2 7 5 4 7 NORTH CENTRAL REGIONAL TRIAL NORTH CENTRAL REGIONAL TRIAL NORTH CENTRAL REGIONAL TRIAL YELLOW FLESH and EUROPEAN TRIAL YELLOW FLESH and EUROPEAN TRIAL YELLOW FLESH and EUROPEAN TRIAL empty table cell empty table cell empty table cell NORTH CENTRAL REGIONAL TRIALNORTH CENTRAL REGIONAL TRIALNORTH CENTRAL REGIONAL TRIALNORTH CENTRAL REGIONAL TRIAL ND3574-5R MN17922 NORLAND ND5084-3R FV8957-10 RED PONTIAC W1148R NORVALLEY ND4093-4RUS MSB107-1 MSE018-1 MN16966 MN18713 ATLANTIC SNOWDEN W1355-1 29 20 19 15 16 19 9 9 11 8 7 7 5 5 2 2 1 5 7 7 9 6 11 8 8 7 8 11 7 4 6 7 1 1 3 3 11 5 9 10 4 5 9 11 10 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell YELLOW FLESH and EUROPEAN TRIALYELLOW FLESH and EUROPEAN TRIALYELLOW FLESH and EUROPEAN TRIALYELLOW FLESH and EUROPEAN TRIAL MSG145-1 LADY CLAIRE YUKON GOLD COLUMBO MSE040-6RY BOLESTRA APELL ELOGE MSE048-2Y VICTORIA WIS75-30 MSA097-1Y SIERRA ZAREVO MSE226-4Y ACCORD 1 2 2 3 3 6 7 5 8 12 empty table cell 9 8 4 7 11 14 24 23 22 24 18 18 18 15 13 12 17 14 14 12 10 6 3 3 4 5 1 3 2 1 1 1 1 1 1 1 1 1 1 2 1 2 2 2 2 4 3 3 1 2 4 3 4 4 6 7 3 6 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 97 80 70 65 62 68 36 30 37 29 24 24 19 17 7 7 30 25 27 23 26 28 25 30 30 28 29 29 27 30 27 30 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 0.033 0.200 0.370 0.391 0.423 0.429 0.960 1.200 1.300 1.357 1.379 1.517 1.963 2.133 2.185 2.233 YELLOW FLESH and EUROPEAN TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell YELLOW FLESH and EUROPEAN TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell YELLOW FLESH and EUROPEAN TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 0.040 0.080 0.083 0.111 0.143 0.250 0.280 0.409 0.455 0.500 0.517 0.560 0.652 0.708 0.833 0.958 25 25 24 27 21 24 25 22 22 24 29 25 23 24 24 24 96 92 92 89 86 75 72 68 59 50 59 56 61 50 42 25 empty table cell empty table cell 1 VARIETY MATILDA ACCENT SW93107 GIGANT SAGINAW GOLD TORRIDON ND2470-27 MSE222-5Y ADAPTATION TRIAL MSG147-3P MSI201-2PY SAXON MSH370-3 MSH384-14 IDA ROSE MSF002-1 MSE028-1 MSG124-8P MSH031-5 ONAWAY MIDAS MSH041-1 MSH321-1 MSG141-3 NAVAN MSH098-2 MSH101-2 MSH361-2 MSH333-3 MSF001-2 MSH217-1 MSG004-3 MSH380-3Y SNOWDEN SUPERIOR MSH015-2 MSH228-6 ROCKET MSH018-5 MSH418-1 MSH094-8 MSH120-1 MSH123-5 TOTAL TUBERS empty table cell empty table cell 4 NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER empty table cell empty table cell NUMBER OF SPOTS PER TUBER 0 3 NUMBER OF SPOTS PER TUBER 5+ 2 5 3 8 5 2 8 4 2 7 5 2 8 7 5 2 empty table cell 4 6 2 8 6 empty table cell 6 7 ADAPTATION TRIAL 1 NUMBER OF SPOTS PER TUBER 9 8 8 7 6 5 4 2 1 2 3 3 5 4 ADAPTATION TRIAL 1 2 5 ADAPTATION TRIAL 1 empty table cell empty table cell 25 23 23 24 23 19 27 24 PERCENT (%) BRUISE FREE 32 35 9 8 9 0 7 0 AVERAGE SPOTS/TUBER 1.120 1.174 1.870 1.917 2.043 2.421 2.593 3.125 ADAPTATION TRIAL ADAPTATION TRIAL ADAPTATION TRIAL ADAPTATION TRIAL ADAPTATION TRIAL ADAPTATION TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 20 16 15 14 14 12 12 11 10 12 11 9 10 7 7 8 7 10 9 7 7 10 6 8 5 4 8 5 4 4 4 5 4 3 6 7 8 8 6 9 8 12 10 7 9 9 11 7 11 10 11 6 7 10 10 9 8 9 9 13 5 10 8 8 9 7 11 10 1 3 1 4 4 3 4 3 2 6 2 3 6 5 5 4 6 5 5 3 8 3 9 7 7 4 10 8 6 6 3 7 2 1 1 2 2 1 1 2 1 2 2 4 2 2 1 3 3 2 1 4 3 2 5 6 5 5 4 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1 1 2 1 1 1 1 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 26 24 26 25 25 25 24 25 24 24 24 24 25 19 25 25 25 24 25 25 25 26 25 25 25 26 25 24 25 25 25 24 25 25 1 1 2 2 1 1 2 1 1 1 empty table cell empty table cell empty table cell 77 67 58 56 56 48 50 44 42 50 46 38 40 37 28 32 28 42 36 28 28 38 24 32 20 15 32 21 16 16 16 21 16 12 0.231 0.375 0.538 0.640 0.680 0.680 0.708 0.720 0.750 0.792 0.833 0.875 0.880 1.000 1.040 1.040 1.080 1.083 1.160 1.200 1.240 1.269 1.320 1.320 1.320 1.346 1.400 1.458 1.520 1.560 1.560 1.583 1.640 1.640 VARIETY MSE273-8 MSH419-1 MSG007-1 MI PURPLE MSF060-6 MSF087-3 MSH095-4 MSG015-C MSH106-2 ATLANTIC MSG049-4 NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER 0 2 10 4 7 3 7 1 1 8 empty table cell 12 6 4 empty table cell 5 5 2 empty table cell 7 1 6 1 3 PRELIMINARY TRIAL 1 3 5 8 7 4 4 9 5 6 3 6 NUMBER OF SPOTS PER TUBER TOTAL TUBERS NUMBER OF SPOTS PER TUBER 5+ 1 2 2 1 NUMBER OF SPOTS PER TUBER 3 4 6 5 5 5 4 6 5 7 4 2 4 25 3 24 1 25 2 25 3 4 empty table cell25 25 3 25 2 23 3 25 3 25 8 23 3 PRELIMINARY TRIAL BRUISE FREE 16 13 4 4 0 16 0 9 0 4 4 PRELIMINARY TRIAL PRELIMINARY TRIAL 4 3 3 2 3 8 PERCENT (%) AVERAGE SPOTS/TUBER 2.080 2.125 2.200 2.200 2.360 2.400 2.400 2.478 2.520 2.960 3.043 PRELIMINARY TRIAL PRELIMINARY TRIAL PRELIMINARY TRIAL PRELIMINARY TRIALPRELIMINARY TRIAL PRELIMINARY TRIAL MSF015-1 MSI178-8 ONAWAY MSH063-A B1865-2 MSI005-20Y MSH013-A MSI005-12Y MSI039-8Y MSI077-5 MSI004-3 MSI005-11Y MSI193-5 MSF090-9 MSI002-3 MSI057-1 MSI037-7 MSI082-3 MSI103-5 MSI083-5 MSI117-1 MSI234-6Y MSF373-8 MSI168-5 MSF382-2 MSI004-2Y MSI005-5 MSI066-2 MSI160-7 MSI026-2 MSH009-A 23 19 22 20 15 17 18 17 17 16 14 15 14 16 11 13 9 15 12 12 11 12 11 12 11 12 10 18 10 11 7 1 2 4 1 1 1 1 1 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1 4 empty table cell 3 4 3 5 6 8 empty table cell 8 empty table cell 9 empty table cell 6 10 empty table cell 8 5 12 empty table cell 7 empty table cell 10 6 10 10 12 10 9 9 11 10 11 10 7 9 7 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 2 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1 empty table cell empty table cell 1 empty table cell empty table cell 1 empty table cell empty table cell 2 empty table cell 1 empty table cell empty table cell24 empty table cell23 empty table cell26 empty table cell25 empty table cell19 empty table cell23 empty table cell25 empty table cell25 empty table cell25 empty table cell25 empty table cell21 empty table cell25 empty table cell24 empty table cell25 empty table cell23 empty table cell22 empty table cell20 empty table cell25 empty table cell24 empty table cell25 empty table cell25 empty table cell25 empty table cell23 empty table cell24 empty table cell25 empty table cell25 empty table cell24 empty table cell35 empty table cell21 empty table cell24 empty table cell17 empty table cell empty table cell empty table cell empty table cell 1 3 1 3 2 3 3 2 3 2 3 6 4 2 2 empty table cell empty table cell empty table cell empty table cell 1 1 96 83 85 80 79 74 72 68 68 64 67 60 58 64 48 59 45 60 50 48 44 48 48 50 44 48 42 51 48 46 41 0.042 0.174 0.192 0.240 0.263 0.304 0.320 0.320 0.320 0.360 0.381 0.400 0.500 0.520 0.522 0.591 0.600 0.600 0.625 0.640 0.640 0.640 0.652 0.667 0.680 0.680 0.708 0.714 0.714 0.792 0.824 PERCENT (%) AVERAGE SPOTS/TUBER VARIETY MSH360-1 MSI083-4 MSI168-2 MSI085-10 SNOWDEN ATLANTIC MSI060-3 MSH017-C MSI053-2 MSG106-5 MSI223-6 MSH306-B MSH067-3 MSI043-1 MSI050-4 MSI172-7 4 1 2 1 TOTAL TUBERS NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER 5+ 1 empty table cell NUMBER OF SPOTS PER TUBER 0 13 10 9 14 9 11 7 7 6 1 8 5 4 1 1 empty table cell empty table cell empty table cell 1 NUMBER OF SPOTS PER TUBER 6 25 6 21 6 21 7 31 6 23 4 23 8 25 7 23 8 25 15 25 7 25 24 11 8 26 11 25 6 26 empty table cell 6 25 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 2 4 3 5 7 5 3 6 5 7 5 3 3 10 6 8 8 3 1 1 1 3 3 3 4 3 4 4 4 2 2 7 10 8 empty table cell empty table cell empty table cell empty table cell 3 1 1 1 3 2 1 BRUISE FREE 52 48 43 45 39 48 28 30 24 4 32 21 15 4 4 0 0.880 0.905 0.905 0.968 1.087 1.174 1.280 1.304 1.360 1.480 1.480 1.542 1.654 1.760 2.154 2.320 empty table cell empty table cell empty table cell SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL 1 1 2 SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL ND2676-10 NY115 AF1668-60 B0564-8 MSA091-1 B0564-9 MSNT-1 W1313 SNOWDEN ND2470-27 NY112 17 21 12 13 12 11 11 13 12 4 2 3 2 9 7 13 10 7 7 8 12 4 1 2 2 3 8 8 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 20 24 22 22 25 22 20 23 24 26 25 1 1 2 7 4 85 88 55 59 48 50 55 57 50 15 8 0.150 0.167 0.500 0.500 0.520 0.545 0.550 0.609 0.708 1.308 2.280 AVERAGE ROUND WHITES: LATE HARVEST SPOTS/TUBER ROUND WHITES: LATE HARVEST TABLE 10B MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS 1999 BLACKSPOT BRUISE SUSCEPTIBILITY TEST CHECK BRUISE SAMPLES** PERCENT (%) 1 3 4 21 BRUISE NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER 0 NUMBER OF SPOTS PER TUBER 5+ NUMBER OF SPOTS PER TUBER 2 TOTAL TUBERS VARIETY ROUND WHITES: LATE HARVESTROUND WHITES: LATE HARVEST ROUND WHITES: LATE HARVESTROUND WHITES: LATE HARVEST ROUND WHITES: LATE HARVEST MSE228-11 MSE149-5Y ONAWAY SNOWDEN SUPERIOR MSF014-9 P83-11-5 MSF099-3 REBA MSE228-1 NY120 MSE221-1 MSB076-2 CHIPETA MSG227-2 MSE246-5 MSC148-A MSE018-1 MSG274-3 MSA091-1 NY115 MSE250-2 MSG050-2 MSF313-3 MSNT-1 NY112 ATLANTIC ROUND WHITES: LATE HARVEST empty table cell empty table cell24 empty table cell empty table cell empty table cell empty table cell24 empty table cell empty table cell25 empty table cell empty table cell23 empty table cell empty table cell25 empty table cell empty table cell25 empty table cell empty table cell24 empty table cell24 1 empty table cell25 1 empty table cell24 1 empty table cell empty table cell23 empty table cell empty table cell23 empty table cell empty table cell23 empty table cell empty table cell23 empty table cell22 1 empty table cell25 1 empty table cell empty table cell25 empty table cell24 1 empty table cell25 3 empty table cell25 1 empty table cell25 3 empty table cell25 1 empty table cell31 1 empty table cell24 2 empty table cell23 4 22 3 LONG WHITES and RUSSETS 24 empty table cell 20 22 22 20 21 21 20 21 21 20 18 17 17 19 17 18 19 16 18 16 19 15 20 15 10 9 0.000 0.048 0.083 0.120 0.130 0.160 0.160 0.167 0.167 0.200 0.208 0.217 0.261 0.261 0.261 0.273 0.320 0.320 0.375 0.400 0.400 0.440 0.440 0.452 0.458 0.739 1.318 1 2 3 3 4 4 4 2 3 3 5 6 6 3 4 6 5 7 4 8 2 9 9 7 9 6 LONG WHITES and RUSSETS LONG WHITES and RUSSETS ROUND WHITES: LATE HARVEST empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell FREE ROUND WHITES: LATE HARVEST empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 100 95 92 88 87 84 84 83 88 84 83 78 74 74 83 77 72 76 67 72 64 76 60 65 63 43 41 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell LONG WHITES and RUSSETS LONG WHITES and RUSSETS empty table cell 1 1 1 1 1 1 2 LONG WHITES and RUSSETS LONG WHITES and RUSSETS LONG WHITES and RUSSETS MSH026-RUS MSE202-3 MSE192-8RUS 25 empty table cell 24 24 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell25 empty table cell25 empty table cell25 1 1 100 96 96 0.000 0.040 0.040 LONG WHITES and RUSSETS LONG WHITES and RUSSETS ** Tuber samples were collected at harvest, graded, and held until evaluation. Samples were abrasive-peeled and scored on October 20, 1999. NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER VARIETY 0 24 ELOGE 24 RUSSET BURBANK RUSSET NORKOTAH 24 A7961-1 23 GEM RUSSET 22 22 ND4093-4RUS 21 INNOVATOR MSG088-6RUS 20 MSB106-7 20 1 1 1 1 2 3 3 4 2 5 PERCENT (%) BRUISE NUMBER OF SPOTS PER TUBER 4 2 NUMBER OF SPOTS PER TUBER empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell NUMBER OF SPOTS PER TUBER 3 NUMBER OF SPOTS PER TUBER FREE 5+ empty table cell 96 empty table cell 96 empty table cell 96 empty table cell 92 empty table cell 88 empty table cell 88 empty table cell 84 empty table cell 87 empty table cell 80 TOTAL TUBERS empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 25 25 25 25 25 25 25 23 25 empty table cell 1 AVERAGE SPOTS/TUBER 0.040 0.040 0.040 0.080 0.120 0.120 0.160 0.174 0.200 NORTH CENTRAL REGIONAL TRIALNORTH CENTRAL REGIONAL TRIALNORTH CENTRAL REGIONAL TRIALNORTH CENTRAL REGIONAL TRIAL ND3574-5R FV8957-10 W1575-30 MN17922 NORVALLEY MSE018-1 ND5084-3R NORLAND RED PONTIAC W1148R SNOWDEN MN1696 6 MSB107-1 ND4093-4RUS W1355-1 ATLANTIC MN1871 3 ND2470-27 27 25 27 23 23 22 20 19 21 21 18 19 19 15 15 15 11 10 3 3 4 6 7 8 5 8 5 5 9 8 10 9 12 9 12 10 2 2 2 4 5 4 4 5 4 6 1 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 2 2 1 2 YELLOW FLESH and EUROPEAN TRIAL 0.100 0.107 0.129 0.207 0.233 0.267 0.269 0.296 0.321 0.321 0.448 0.516 0.588 0.607 0.788 0.806 0.821 1.000 YELLOW FLESH and EUROPEAN TRIAL 90 89 87 79 77 73 77 70 75 75 62 61 56 54 45 48 39 36 30 28 31 29 30 30 26 27 28 28 29 31 34 28 33 31 28 28 YELLOW FLESH and EUROPEAN TRIAL NORTH CENTRAL REGIONAL TRIAL NORTH CENTRAL REGIONAL TRIAL NORTH CENTRAL REGIONAL TRIAL NORTH CENTRAL REGIONAL TRIAL NORTH CENTRAL REGIONAL TRIAL NORTH CENTRAL REGIONAL TRIAL YELLOW FLESH and EUROPEAN TRIAL YELLOW FLESH and EUROPEAN TRIAL YELLOW FLESH and EUROPEAN TRIAL YELLOW FLESH and EUROPEAN TRIAL YELLOW FLESH and EUROPEAN TRIAL YELLOW FLESH and EUROPEAN TRIALYELLOW FLESH and EUROPEAN TRIAL YUKON GOLD COLUMBO MSG145-1 ACCENT ACCORD APELL BOLESTRA MSE226-4Y LADY CLAIRE SW93 107 ZAREVO 25 empty table cell 24 24 23 23 23 23 23 22 22 22 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 25 25 25 25 25 25 25 25 25 25 25 1 1 2 2 2 2 2 3 3 3 100 96 96 92 92 92 92 92 88 88 88 0.000 0.040 0.040 0.080 0.080 0.080 0.080 0.080 0.120 0.120 0.120 PERCENT (%) BRUISE AVERAGE SPOTS/TUBER 0.160 0.160 0.200 0.200 0.200 0.200 0.273 0.280 0.400 1.160 ADAPTATION TRIAL ADAPTATION TRIAL ADAPTATION TRIAL VARIETY MATILDA TORRIDON MSA097-1Y MSE048-2Y SIERRA VICTORIA MSE040-6RY GIGANT SAGINAW GOLD MSE222-5Y ADAPTATION TRIAL MSE273-8 MSG049-4 ONAWAY MSH370-3 MSH120-1 MSG007-1 MSG141-3 MSH384-1Y MSG124-8P MSH098-2 IDAROSE MSE028-1 MSF002-1 MSH031-5 MSH041-1 MSH419-1 MSH321-1 MSI201-2PY MSG004-3 MSH380-3Y MSH101-2 MSH015-2 MIDAS MI PURPLE MSH018-5 MSH123-5 MSH094-8 SAXON SUPERIOR MSH228-6 3 4 2 1 1 2 1 2 4 NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER 5+ empty table cell NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER 1 ADAPTATION TRIAL 1 TOTAL TUBERS empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell NUMBER OF SPOTS PER TUBER 0 21 22 20 21 22 20 16 19 17 9 ADAPTATION TRIAL 1 4 empty table cell 2 5 3 1 empty table cell 5 6 empty table cell 5 6 9 25 25 25 25 25 25 22 25 25 25 ADAPTATION TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell FREE 84 88 80 84 88 80 73 76 68 36 ADAPTATION TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell ADAPTATION TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1 empty table cell empty table cell 1 ADAPTATION TRIAL empty table cell 1 empty table cell 1 empty table cell 1 empty table cell 1 2 empty table cell 2 empty table cell 2 empty table cell 2 empty table cell 3 empty table cell 3 empty table cell 4 empty table cell 5 empty table cell 3 3 5 empty table cell 5 empty table cell 5 empty table cell 7 empty table cell 4 empty table cell 7 empty table cell 3 5 empty table cell 5 empty table cell 6 7 6 4 7 24 23 23 22 23 22 22 22 21 21 20 19 20 20 19 19 15 17 18 16 17 18 18 17 18 16 12 16 20 empty table cell 15 1 empty table cell 1 empty table cell 1 empty table cell 1 empty table cell 1 empty table cell 3 1 empty table cell 25 24 24 23 25 24 24 24 24 24 24 24 24 24 24 24 20 24 23 23 22 24 24 24 26 23 17 24 24 23 96 96 96 96 92 92 92 92 88 88 83 79 83 83 79 79 75 71 78 70 77 75 75 71 69 70 71 67 83 65 empty table cell 2 empty table cell 1 1 1 1 1 7 0.040 0.042 0.042 0.043 0.080 0.083 0.083 0.083 0.125 0.125 0.167 0.208 0.208 0.208 0.208 0.208 0.250 0.292 0.304 0.304 0.318 0.333 0.333 0.333 0.346 0.348 0.353 0.375 0.375 0.391 VARIETY SNOWDEN MSH418-1 MSF001-2 MSH217-1 MSH361-2 MSH333-3 MSH106-2 ROCKET MSH095-4 NAVAN MSF087-3 MSF060-6 ATLANTIC MSG015-C PRELIMINARY TRIALPRELIMINARY TRIAL MSI004-2Y MSI004-3 MSI005-20Y MSI160-7 SNOWDEN MSF015-1 MSH009-A MSI026-2 MSI039-8Y MSH360-1 MSF090-9 MSI005-11Y MSI005-12Y MSI050-4 MSI117-1 MSI193-5 ONAWAY MSI053-2 MSI037-7 B1865-2 MSI057-1 MSI083-4 MSI083-5 MSI085-10 MSI082-3 MSI103-5 25 25 25 25 21 24 24 24 24 24 23 23 23 23 23 23 23 21 15 22 23 22 18 19 21 21 3 1 2 1 1 3 1 2 3 4 6 1 1 1 4 1 1 NUMBER OF SPOTS PER TUBER 1 2 3 2 4 4 4 1 4 5 5 5 empty table cell NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER empty table cell empty table cell empty table cell empty table cell TOTAL TUBERS empty table cell empty table cell empty table cell empty table cell empty table cell NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER 0 5+ 13 16 16 19 13 13 11 10 10 11 9 8 8 4 1 9 7 3 5 6 6 7 11 7 8 8 6 4 8 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1 empty table cell 2 empty table cell 1 empty table cell 1 2 empty table cell 22 25 22 26 23 23 23 26 23 24 25 24 23 25 PRELIMINARY TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell FREE 59 64 73 73 57 57 48 38 43 46 36 33 35 16 PRELIMINARY TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 100 100 100 100 100 96 96 96 96 92 92 92 92 92 92 92 92 91 88 88 92 88 86 90 84 84 PRELIMINARY TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell 1 1 PRELIMINARY TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1 empty table cell 1 empty table cell 1 empty table cell 1 2 empty table cell 2 empty table cell 2 empty table cell 2 empty table cell 2 empty table cell 2 empty table cell 2 empty table cell 2 empty table cell 2 empty table cell 2 empty table cell 3 empty table cell 1 3 empty table cell 3 empty table cell 1 4 empty table cell 4 empty table cell PRELIMINARY TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 25 25 25 25 21 25 25 25 25 26 25 25 25 25 25 25 25 23 17 25 25 25 21 21 25 25 2 1 1 PERCENT (%) BRUISE AVERAGE SPOTS/TUBER 0.409 0.480 0.500 0.538 0.652 0.696 0.783 0.846 0.913 1.125 1.240 1.375 1.522 1.800 PRELIMINARY TRIAL PRELIMINARY TRIAL PRELIMINARY TRIAL 0.000 0.000 0.000 0.000 0.000 0.040 0.040 0.040 0.040 0.077 0.080 0.080 0.080 0.080 0.080 0.080 0.080 0.087 0.118 0.120 0.120 0.120 0.143 0.143 0.160 0.160 VARIETY MSI178-8 MSI234-6Y MSH013-A MSH063-A MSH067-3 MSI168-2 MSI066-2 MSI055-5 MSI168-5 ATLANTIC MSI002-3 MSF373-8 MSF382-2 MSG106-5 MSI060-3 MSH306-B MSH017-C MSI223-6 MSI172-7 MSI043-1 PERCENT (%) AVERAGE SPOTS/TUBER 3 2 1 NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER empty table cell TOTAL TUBERS empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell BRUISE NUMBER OF SPOTS PER TUBER 4 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell NUMBER OF SPOTS PER TUBER NUMBER OF SPOTS PER TUBER 0 5+ 21 21 18 20 21 20 29 21 22 19 20 17 19 16 16 17 15 15 13 7 FREE 84 84 82 80 84 80 85 84 88 83 80 68 79 67 76 68 60 63 52 28 SNACK FOOD ASSOCIATION TRIAL 0.160 0.160 0.182 0.200 0.200 0.200 0.206 0.240 0.240 0.304 0.320 0.360 0.375 0.417 0.429 0.480 0.520 0.583 0.760 1.400 SNACK FOOD ASSOCIATION TRIAL empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell25 empty table cell25 empty table cell22 empty table cell25 empty table cell25 empty table cell25 empty table cell34 empty table cell25 empty table cell25 empty table cell23 empty table cell25 empty table cell25 empty table cell24 empty table cell24 21 empty table cell25 empty table cell25 empty table cell24 1 empty table cell25 1 empty table cell25 SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL empty table cell empty table cell 1 1 4 4 4 5 3 5 4 2 1 2 3 7 2 6 4 5 8 4 8 8 empty table cell empty table cell empty table cell 2 1 1 1 1 2 2 2 1 5 2 4 1 1 1 1 1 1 1 1 5 SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIALSNACK FOOD ASSOCIATION TRIALSNACK FOOD ASSOCIATION TRIAL SNACK FOOD ASSOCIATION TRIAL B0564-9 ND2676-10 SNOWDEN AF1668-60 MSNT-1 MSA091-1 B0564-8 NY115 W1313 ND2470-27 NY112 26 empty table cell 24 empty table cell 24 empty table cell 25 24 23 22 22 19 18 14 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell26 empty table cell24 empty table cell24 empty table cell26 empty table cell25 empty table cell24 empty table cell24 empty table cell24 empty table cell24 empty table cell25 empty table cell22 empty table cell 1 1 1 2 2 5 4 3 2 5 1 100 100 100 96 96 96 92 92 79 72 64 0.000 0.000 0.000 0.038 0.040 0.042 0.083 0.083 0.208 0.440 0.591 TABLE 11 LINE TRIAL LESION DEPTH (mm) 1999 FUSARIUM DRY ROT TRIAL MICHIGAN STATE UNIVERSITY POTATO BREEDING and GENETICS LESION DIAMETER (mm) LINE TRIAL LESION DEPTH (mm) LESION DIAMETER (mm) LINE TRIAL LESION DEPTH (mm) LESION DIAMETER (mm) AD AD AD NC PRE PRE DOH DOH AD AD AD AD AD AD AD DOH Russet Norkotah LONG MSH106-2 Midas MSG004-3 Snowden MSI050-4 MSG106-5 NY120 P83-11-5 Navan Snowden MSH031-5 Superior MSH228-6 Ida Rose Rocket Chipeta Russet Burbank CHECK MSI193-5 Superior MN16966 MSH120-1 HLG7-3 Zarevo MSE018-1 Lady Claire MSG049-4 Russet Burbank Saxon Reba NY112 MSE202-3RUS MSF099-3 MSHI01-2 MSE246-5 Red Pontiac MSH018-5 MSG227-2 Onaway MSG007-1 MSF087-3 MSI223-6 MSH123-5 Yukon Gold MI Purple Onaway Torridon Snowden MSH380-3Y MSH361-2 MSF313-3 MSB076-2 Russet Burbank CHECK MSH370-3 MSG145-1 Snowden MSH026-3RUS PRE DOH NC AD PRE EURO DOH EURO AD LONG AD DOH DOH LONG DOH AD DOH NC AD DOH AD AD AD PRE AD EURO AD DOH EURO PRE AD AD DOH DOH AD EURO DOH LONG 2.9 3.1 3.3 3.4 3.5 3.5 3.7 3.7 3.8 3.8 3.8 3.8 3.9 4.0 4.1 4.1 4.1 4.5 4.6 4.6 4.6 4.7 4.7 4.7 4.7 4.7 4.8 4.8 4.8 4.8 4.9 4.9 5.0 5.0 5.1 5.3 5.4 5.4 5.4 5.5 5.6 5.6 5.6 5.6 5.6 5.6 5.7 5.7 5.8 5.8 5.8 5.8 5.9 5.9 5.9 6.0 6.0 11.4 7.5 7.4 6.9 8.8 7.5 14.8 9.4 11.3 12.8 7.9 8.3 7.5 10.8 8.8 12.7 9.2 9.2 8.0 9.2 14.5 10.6 10.4 10.9 11.1 12.0 10.0 13.2 10.3 10.2 10.1 10.5 10.4 11.1 13.9 8.6 14.4 11.4 10.3 10.4 9.1 9.6 10.5 14.5 10.4 10.8 21.3 10.0 9.8 10.0 11.0 14.7 11.0 12.2 23.6 11.2 17.2 PRE PRE EURO PRE NC AD EURO DOH DOH NC EURO EURO NC EURO DOH DOH NC AD PRE PRE DOH DOH LONG EURO AD EURO LONG PRE PRE AD PRE LONG EURO AD NC DOH NC PRE MSI060-3 MSI103-5 Matilda MSI168-2 ND3574-5R MSF002-1 Bolestra Atlantic MSC148-A MSE018-1 Sierra Gigant Wis75-30 MSE040-6RY MSNT-1 MSF014-9 W1355-1 MSG015-C MSI004-2Y MSI082-3 MSE221-1 MSG050-2 A7961-1 Accent MSH098-2 Accord Gem Russet Onaway MSI066-2 MSH333-3 MSH009-A Innovator MSA097-1 MSH384-1Y ND2470-27 MSA091-1 W1148R MSI055-5 MSE192-8RUS LONG B1865-2 MSH360-1 MSH094-8 MSH419-1 MSE149-5Y Norland MSI037-7 MSI083-5 MSH306-B MSE222-5Y ND4093-4RUS NC PRE MSI053-2 MSG088-6RUS LONG MSF373-8 Colombo MSI117-1 Victoria NY115 PRE PRE AD AD DOH NC PRE PRE PRE EURO PRE EURO PRE EURO DOH PRE PRE AD AD LONG PRE PRE DOH AD PRE AD AD NC 6.1 6.1 6.1 6.2 6.2 6.2 6.2 6.3 6.3 6.3 6.4 6.4 6.5 6.5 6.6 6.7 6.8 6.8 6.9 6.9 6.9 7.1 7.1 7.1 7.2 7.2 7.3 7.3 7.4 7.5 7.5 7.6 7.7 7.7 7.7 7.8 7.8 7.8 7.9 8.0 8.0 8.0 8.1 8.1 8.1 8.1 8.1 8.3 8.4 8.4 8.5 8.5 8.6 8.6 8.6 8.7 8.9 8.9 9.0 9.1 9.2 9.3 9.3 9.4 9.4 9.5 9.6 9.7 9.7 9.8 20.5 15.2 12.4 15.8 17.2 17.3 14.0 15.2 16.2 12.1 13.7 16.8 17.5 17.7 11.6 22.6 14.8 14.1 16.2 14.4 12.6 12.9 14.6 33.6 15.4 13.9 22.6 13.7 13.5 13.1 17.0 28.4 19.5 16.3 22.0 13.1 17.1 15.5 13.3 15.3 19.9 20.0 15.1 19.8 17.6 14.2 17.9 15.4 15.3 12.2 25.4 15.0 14.1 16.9 19.8 15.1 13.9 16.6 16.2 14.0 14.8 21.7 24.8 19.2 15.8 18.0 15.5 21.5 22.5 31.9 10.1 10.2 10.2 10.3 10.5 10.5 10.5 10.5 10.6 10.8 10.8 10.9 10.9 11.0 11.0 11.2 11.2 11.4 11.5 11.5 11.6 11.6 11.8 11.8 12.1 12.1 12.2 12.3 12.8 12.8 13.1 13.3 13.5 13.7 14.2 15.4 16.4 16.6 17.5 18.5 18.7 19.5 20.0 20.7 MSI172-7 PRE PRE MSH013-A HLG3-A PRE PRE MSI005-12Y AD MSH321-1 MSE228-11 DOH ND4093-4RUS LONG MSI160-7 PRE PRE MSI083-4 AD MSH015-2 AD MSH418-1 DOH MSE250-2 MN17922 NC MSG141-3 AD FV8957-10 NC MSI178-8 PRE MSG147-3P AD MSH041-1 AD PRE MSI005-20Y MSF0I5-1 PRE PRE MSI004-3 MSH095-4 AD DOH MSG274-3 Saginaw Gold EURO MSH217-1 MSI043-1 MSI085-10 MSI057-1 MSE226-4Y MSI005-11Y MSI026-2 MSF090-9 SW93107 MSE028-1 MN18713 Eloge MSB107-1 Atlantic Apell MSE048-2Y MSI002-3 ND5084-3R MSF382-2 MSG124-8P empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell AD PRE PRE PRE EURO PRE PRE PRE EURO AD NC EURO NC NC EURO EURO PRE NC PRE AD empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 20.5 28.5 18.2 31.4 14.9 19.5 19.4 17.0 16.8 17.8 17.5 20.6 26.5 15.7 30.0 21.2 16.1 19.7 22.2 24.0 20.4 21.2 15.6 27.5 16.7 24.4 26.2 17.7 27.1 25.0 30.2 19.6 20.9 20.3 17.4 24.7 30.8 28.8 29.4 38.6 38.6 25.5 34.7 51.4 empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cellempty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell MSI039-8Y empty table cell MSH017-C empty table cell NY121 empty table cell MSE273-8 empty table cell MSB106-7 empty table cell Atlantic empty table cell MSI168-5 empty table cell MSE228-1 empty table cell MSF060-6 empty table cell MSI234-6Y empty table cell MSI201-2PY empty table cell MSF001-2 empty table cell Norvalley Depth LSD 0.05 = 4.1 Diameter LSD 0.05 = 7.0 Funding: Federal Grant, MPIC and SFA 1999 On-Farm Potato Variety Trials Dr. Dick Chase, Dr. Dave Douches, Don Smucker (Montcalm), David Glenn (Presque Isle), Paul Marks (Monroe) and Jim Isleib (Alger) Introduction On-farm potato variety trials were conducted on eleven farms in 1999; four evaluating fresh market entries, five evaluating processing entries, one for yellow fresh entries and the SFA Chip Trial. The fresh market cooperators were Horkey Bros. (Monroe), Brian Williams (Sanilac), Cliff Wilk (Presque Isle) and Lippens Potato Farm (Delta). The processing trial cooperators were Crooks Potato Farms (St. Joseph), L. Walther and Sons, Inc. (St. Joseph), W.J. Lennard and Sons, Inc. (Monroe), Kevin Denniston (Allegan) and Sandyland Farms (Montcalm). The SFA Chip Trial was at V & G Farms (Montcalm) and a specialty variety trial at Fedak Farms (Bay). Procedure There were 12 entries in both the fresh market and processing trials and 14 of the total entries were from the MSU potato breeding program. For each trial, 25 pounds of seed were provided for planting in single rows. At the Walther Farm in St. Joseph County, the seed was planted so that three separate harvest dates could be evaluated. During the growing season, observation of emergence, stands, vigor, general growth and maturity are noted. At harvest, a yield check was made for each entry from a uniformly sized plot area. Size distribution, yields, specific gravity and internal defects were determined. From each processing trial location, chip samples were collected and processed in the MSU Potato Processing Lab. Results A. Freshpack Trial Results The overall average of the three locations are shown in Table 1. The yield data from the Horkey Farm in Monroe County are not included because of severe water damage (5 1/2 inches) on June 12-13. The trial locations in Sanilac and Delta County were not irrigated. NY112 (Atlantic x Q155-3). This entry is primarily targeted for chip processing. It is a high yielder with a very scurfy skin texture and medium SG. It has scab resistance similar to Superior. The only internal defect noted was 3/10 HH at the Delta County location. MSE228-1 (Russet Nugget x Spartan Pearl). Has above average yields and was the highest yielder in 1998. Specific gravity is medium-low and scab susceptibility is intermediate, similar to Atlantic and Snowden. Defects noted at harvest that were minimal were vascular discoloration, HH and growth cracks. General appearance was good. MSE149-5Y (Saginaw Gold x ND860-2). Continues to be a high yielder with a light yellow flesh and low SG. General appearance has been very good with only minimal defects of vascular discoloration and IBS noted in Delta County. It may set shallow as greening was noted in Sanilac County. Scab tolerance is better than Yukon Gold and similar to Russet Norkotah. MSE018-1 (Gemchip x W877). Was evaluated in both the fresh market and processing trials. It is a late maturing, high yielding and high specific gravity advanced seedling with an erect, large vine. It has an attractive, blocky-oval shape and is intermediate in scab susceptibility. It has variable chip quality. MSE221-1 (Superior x Spartan Pearl). Has an above average yield and very good scab resistance. It has a medium-early maturity and low SG. Growth cracks and HH have been significant and air checks were noted in Presque Isle County. Onaway. Included as a check variety. Reba (Monona x Allegany) formerly, NY87. Is a recent release from Cornell. Yields were average with bright skin and good general appearance. Scab resistance is intermediate and similar to Russet Norkotah. Hollow heart and brown center were noted at the Delta County location. MSF313-3 (Spartan Pearl x NY88). Had average yields with zero pick-outs at all locations. Internal defects were minimal and scab susceptibility is intermediate. This was a new entry to on-farm trials. MSG141-1 (Spartan Pearl x Zarevo). Had average yields. It was a new entry in 1999 and scab resistance is above average. It had a high SG and tuber sizing was in the mid-size range, minimal internal defects, very low pick-outs and good general appearance. MSE228-11 (Russet Nugget x Spartan Pearl). Had below average yields. Scab susceptibility similar to Atlantic and Snowden. Size range was generally small, zero pick- outs and some growth cracks and irregular shape in Delta County. MSE250-2 (Andover x W877). Produced a below average yield. It has been in previous processing trials and has medium-high SG and has chipped from below 50F storage. Tuber shape is blocky to oblong. MSG274-3 (Tollocan x Chaleur). Is a late maturing selection which has a high tuber set (15-18), oval shape, shallow eyes and very attractive fresh market appearance. This entry was also in the processing trial and has excellent late blight tolerance. Due to the heavy tuber set, sizing was generally small. B. Processing Trial Results Table 2 contains the overall average yields, size distribution and specific gravity from the Processing Trials in St. Joseph, Allegan, Monroe and Montcalm Counties. The data from the Walther Farm in St. Joseph County are not included in the table as there were three harvest dates and the size parameters were different. Atlantic. Check variety. Considerable HH and some IBS were the major defects. MSE018-1 (Gemchip x W877). Produced high yields similar to freshpack trials. High SG and very few pick-outs. Slight internals, mostly VD and HH. Chip scores averaged 2.0 and mostly internal defects of SED, VD and color. NY115 (Pike x NY88). Produced above average yields with low SG. Tubers are bright, good general appearance and pick-outs are very low. The chip score average 1.7 on a sample out-of-the field. During the early growth, the plants showed herbicide susceptibility but did not appear damaging. MSF099-3 (Snowden x Chaleur). Had above average yields of blocky-oval shaped tubers. SG is high and it is susceptible to scab; at the Monroe location it was severe. No internal defects were noted and the chip scores averaged 2.4. Average chip quality was 1.7. Chipeta. Had been evaluated several years ago and was judged to be a late variety. With some interest to evaluate it for out-of-the field harvest and lower N, it was included in 1999. Yields were variable and pick outs of HH and cracks averaged 8%. MSA091-1 (MS702-80 x Norchip). Had average yields and medium SG. MSA091-1 has very good scab tolerance similar to Superior. It had very good early growth. At harvest, apical IBS was noted in St. Joseph County and only traces of HH and VD. Average chip score was 1.8 with some SED and VD. Snowden. Check variety. Yields were erratic and appeared to be below those normally expected. At harvest, internal defects were minimal with some VD and HH. Average chip score was 1.7. MSG227-2 (Prestile x MSC127-3). Produced average yields with good SG. It was below average in early plant vigor with smaller plants. Scab resistance is similar to Superior. Tuber size was generally small and some growth crack was noted. Average chip score was 1.8 with mostly SED and VD. Pike. Check variety was included at three locations of St. Joseph, Allegan and Montcalm. Yields were below average and high SG. There was no internal necrosis noted at all locations. The average chip score was 1.6. MSNT-1 (MS716-15 OP). Produced below average yields and a 1.080 SG. It has very good scab tolerance and minimal internal defects. It had above average early growth and plant vigor and a trace of growth cracks. Average chip score was 1.7 and very similar to Snowden. MSE246-5 (E55-27 x W870). Produced below average yields and high SG. Size was generally small with 24% below 2 inches. Scab susceptibility is similar to Russet Norkotah, but better than Atlantic and Snowden. Early plant growth was above average with good vigor. Plants are dense and appear to be heavily branched. Internal and external at-harvest tuber defects were zero and no scab was noted at the Monroe location. Average chip score was 1.7. MSG274-3 (Tollocan x Challeur). Yields were very similar to freshpack trial with a heavy set and generally small sizing. Excellent general appearance for fresh market. The plantings at the Walther Farm in St. Joseph County were designed for three harvest intervals of 98, 119 and 140 days after planting on May 11. These data are shown in Tables 3, 4 and 5 and the sizes used were those of the Walthers Farms evaluation. Pick-outs and culls were not recorded. NY115 was the highest yielder across the three harvest dates, suggesting that it sets and sizes tubers early. MSE018-1, a late variety, shows consistent high yields and SG at 119 and 140 days. Atlantic, Snowden and Chipeta all showed considerable hollow heart. MSG274-3 had similar results when compared with the other trials. C. Specialty Variety Trial A selection of advanced seedlings with various tuber types was conducted at Fedak Farms in Bay County. The performance data are shown in Table 6. Yields were lower than normal due to a second year of being planted to potatoes. A foliar application of metribuzin was made five days before a June 24 observation and any effects are noted. Reba (Monona x Allegany). Is a release from Cornell and was tested as NY87. It has received interest in the Northeast because of a bright skin and good general appearance. It was the highest yielder with good size distribution and no pick-outs. It was slower in its early growth and showed symptoms of metribuzin injury. Scab tolerance is better than Snowden and Atlantic. MSE048-2Y (Saginaw Gold x MS702-80). Produced good yields, medium-high SG and a good yellow flesh. Emergence and early growth were average and it showed some metribuzin symptoms. Scab tolerance is better than Snowden and Atlantic. Eva [NY103-Steuben x (Neotbr x tbr)]. Has been a high yielder in most of our trials. It has a bright appearance, shallow eyes and minimal internal defects. It has intermediate scab tolerance. It showed slight metribuzin symptoms. MSE149-5Y (Saginaw Gold x ND860-2). Produced good yields of uniform size and smooth potatoes. It has a light yellow flesh. Scab tolerance is better than Yukon Gold. Plant vigor was uniform, above average and showed very slight effect from metribuzin. MI Purple. Has a purple skin and white flesh. Most of the tuber size was between 2" and 3 1/4" with no internal defects. Yukon Gold. Included as a check variety. Early growth and vigor were below the average. Some metribuzin injury was noted. MSE192-8Rus (A8163-8 x Russet Norkotah). Was slower in emergence and early growth and had a smaller plant. In some trials, the tuber type has been very good with uniform russetting, smooth and it has scab tolerance similar to Superior. It has a low SG and very minimal internal defects. NYE11-45 (Rosa x Q155-3). Is an advanced seedling from Cornell for tablestock use. It is reported to have resistance to scab and no decision has been made for release. MSA097-1Y (Superior x Norchip). Yielded below average and did have a nice yellow flesh. It has very good scab tolerance. MSE040-6RY (Rose Gold x Fontenot). Produced below average yields with a medium red skin and a good yellow flesh. Scab resistance is better than Yukon Gold. MSG274-3 (Tollocan x Chaleur). Has very good tolerance to late blight. Tuber size is small with very good fresh market appearance. MSE202-3Rus (selection from a USDA-Aberdeen cross). Produced low yields of small potatoes. D. SFA Chip Trial Michigan is one of the seven locations of the SFA Potato Chip Variety Trial sponsored by the Snack Food Association. The trial was located at V & G Farms in Stanton. There were 10 advanced seedlings which were compared with Atlantic and Snowden. The 10 entries were provided by six potato breeders: MSA091-1 and MSNT-1 (MSU-Douches); NY112 and NY115 (Cornell-Plaisted); ND2676-10 and ND2470-17 (ND-Novy); W1313 (WI-Groza); AF1668-60 (ME-Reeves) and BO564-8 and BO564-9 (USDA-Beltsville-Haynes). During 1999 the ND2676-10 advanced seedling was named Dakota Pearl and application for Plant Variety Protection has been made. Table 7 summarizes the yields, size distribution, specific gravity and relative maturity. Yields were generally lower than normal, however, five entries produced greater than 300 cwt/A of U.S. No. 1's. Atlantic was not included and Snowden yields were well below normal. Hollow heart was severe in BO564-9 and was also noted in NY112, Snowden and W1313. The latest maturing entries were NY112 and W1313. Dakota Pearl (ND2676-10), AF1668-60 and NY115 showed the earliest maturity. Entries showing the greatest tolerance to blackspot bruise were ND2676-10 and NY115. Those showing the greatest susceptibility were NY112, ND2470-27 and W1313. Table 8 summarizes the chip quality data for out-of-the field samples processed and scored at MSU and post-harvest samples chipped and scored by Jays Foods on September 29,1999. Table 1. 1999 Freshpack Potato Variety Trials Overall Average — Three Locations (Presque Isle, Sanilac, Delta) Yield Yiel d (cwt/A) (cwt/A) Percent Size Distribution Percent Size Distribution Percent Size Distribution Entry NY112 MSE228-1 MSE149-5Y MSE018-1 MSE221-1 Onaway Reba MSF313-3 MSG141-1 MSE228-11 MSE250-2 MSG274-3199 324 No. 1 392 377 369 365 348 329 306 300 300 283 203 Total 421 406 407 398 385 357 338 334 340 333 235 2-31/4" No. 1 Percent Size Distribution <2" 93 7 82 92 77 7 82 8 90 92 70 8 90 77 5 72 7 92 9 90 79 90 10 78 11 83 88 85 84 15 14 79 86 37 60 62 >3 1/4" 11 15 8 22 13 20 10 12 5 1 6 2 Table 2. 1999 MSU Potato Processing Trial Overall Average - Four Locations (St Joseph, Allegan, Monroe, Montcalm) Yield (cwt/A) Total 401 401 390 382 377 366 378 336 326 321 316 410 Yield (cwt/A) No. 1 373 339 336 334 317 313 312 281 281 265 240 239 Entry Atlantic MSE018-1 NY115 1/ MSF099-3 Chipeta MSA091-1 Snowden MSG227-2 Pike 2/ MSNT-1 MSE246-5 MSG274-3 l/ Three locations. 2/ Two locations. Percent Size Distribution Percent Size Distribution Percent Size Distribution 2-3 1/4" No. 1 Percent Size Distribution <2" 7 93 81 74 85 13 85 13 77 12 75 87 9 83 71 74 10 85 82 17 76 14 83 79 85 13 87 16 79 82 24 75 76 57 57 38 >3 1/4" 12 11 8 12 12 10 6 4 2 3 1 0 0 1 1 0 4 1 2 0 1 0 0 1 0 2 1 1 8 5 0 3 0 2 0 4 S.G. 1.087 1.079 1.079 1.097 1.080 1.073 1.082 1.083 1.092 1.091 1.099 1.087 S.G. 1.085 1.085 1.070 1.083 1.079 1.080 1.081 1.083 1.092 1.080 1.091 1.079 Percent Size Distribution Pick Outs Percent Size Distribution Pick Outs Table 3. 1999 MSU Potato Processing Trial (1) L. Walther and Sons, Inc. — St. Joseph County Yield (cwt/A) No. 1 437 387 344 340 338 322 318 318 306 301 295 260 Entry NY115 MSA091-1 MSF099-3 Snowden MSNT-1 Pike MSE018-1 Atlantic MSG274-3 MSE246-5 Chipeta MSG227-2 Yield (cwt/A) Percent Size Distribution 1/ No. 1 Total 474 92 406 95 398 87 387 88 361 94 85 377 84 379 359 89 469 65 84 359 92 320 336 77 85 1/ 1.87-4" Percent Size Distribution Percent Size Distribution 1/ <1.87" Percent Size Distribution 1/ >4" 0 0 0 0 0 0 0 0 0 0 0 0 empty table cell 92 95 87 88 94 85 84 89 65 84 92 77 empty table cell S.G. Comments 1.073 1.076 1.086 1.077 1.081 1.081 1.079 1.078 1.074 1.088 1.065 1.074 empty table cell 1.077 0/10 2/10 VD 2/10 BC 2/10 VD 3/10 BC, 1/10 BC 2/10 VD 0/10 0/10 0/10 0/10 1/10 VD, 1/10 IBS 0/10 8 5 13 12 6 15 16 11 35 16 8 23 empty table cell AVERAGE 330 385 Planted: May 11, 1999 Harvested: August 17, 1999 (98 days) Table 4. 1999 MSU Potato Processing Trial (2) L. Walther and Sons, Inc. — St. Joseph County Entry NY115 MSE018-1 Atlantic Pike Snowden MSG227-2 Chipeta MSG274-3 MSA091-1 MSF099-3 MSNT-1 MSE246-5 AVERAGE Yield No. 1 Percent Size Distribution 1/ <1.87" Yiel d (cwt/A) Total 654 3 4 652 1 584 5 580 562 3 15 611 4 539 31 736 4 474 476 10 2 408 371 93 7 Percent Size Distribution 1/ Percent Size Distribution 1/ 1.87-4” 97 96 99 95 97 85 93 69 96 90 98 93 empty table cell Percent Size Distribution 1/ >4" 0 0 0 0 0 0 3 0 0 0 0 0 empty table cell (cwt/A) No. 1 631 627 580 551 545 517 517 504 455 428 400 346 508 554 S.G. 1.084 1.084 1.084 1.091 1.080 1.083 1.077 1.085 1.080 1.082 1.078 1.092 empty table cell 1.082 97 96 99 95 97 85 96 69 96 90 98 92 Comments 2/10 HH 4/10 HH 8/10 HH 0/10 1/10 HH 1/10 HH 6/10 HH 0/10 3/10 BC 0/10 1/10 HH, 1/10 BC 0/10 empty table cell Planted: May 11, 1999 Harvested: September 7, 1999 (119 days) 1/ Sizes used in Walther Farms evaluation. Pick-outs/culls not determined. Table 5. 1999 MSU Potato Processing Trial (3) L. Walther and Sons, Inc. — St. Joseph County Yield Yiel (cwt/A) d (cwt/A) Total 590 572 572 531 533 609 449 453 424 No. 1 584 551 549 523 512 480 433 414 402 Percent Size Distribution 1/ <1.87" Percent Size Distribution 1/ 1.87-4” Percent Size Distribution 1/ Percent Size Distribution 1/ >4" 0 0 0 0 0 0 0 0 0 No. 1 98 96 95 97 95 76 91 91 94 98 96 95 97 95 76 91 91 94 2 4 5 3 5 24 9 9 6 Comments 8/10 HH 7/10 HH 2/10 int. nec. 3/10 HH, sl. scab 9/10 HH S.G. 1.083 1.079 1.077 1.087 1.077 1.078 empty table cell 1.074 1.083 1.076 2/10 HH, some gr. crack 2/10 int. nec., sticky stems 1/10 HH, 1/10 int. nec., gr. crack 91 88 422 379 387 9 12 338 336373 89 11 459 91 88 89 empty table cell 0 0 0 empty table cell 492 92 1.085 empty table cell 1.074 1.088 empty table cell 1.080 empty table cell empty table cell Sticky stems, some pointed Entry Atlantic Snowden NY115 MSE018-1 Chipeta MSG274-3 MSNT-1 MSF099-3 MSA091-1 Pike MSG227-2 MSE246-5 AVERAGE Planted: May 11, 1999 l/ Sizes used in Walther Farms evaluation. Pick-outs/culls were not determined. Harvested: September 28, 1999 (149 days) Table 6. 1999 Specialty Potato Variety Trial Fedak Farms — Bay County Yield (cwt/A) Yield (cwt/A) Percent Size Distribution Percent Size Distribution Percent Size Distribution Percent Size Distribution Entry Reba No. 1 348 Total 359 No. 1 97 <2" 3 2-3 1/4" 80 >3 1/4" 17 Percent Size Distribution Pick Outs Comments S.G. 1.080 0 MSE048-2Y Eva (NY103) MSE149-5Y MI Purple Yukon Gold MSE192-8Rus NYE11-45 MSA097-1Y MSE040-6RY MSG274-3 MSE202-3Rus AVERAGE Planted: May 10, 1999. 328 287 285 273 242 234 195 183 176 147 144 237 365 306 324 293 265 264 243 223 268 329 214 288 90 94 88 93 91 89 80 82 66 44 67 82 10 6 12 7 9 11 20 18 34 56 33 81 94 88 93 91 89 80 76 66 44 67 9 0 0 0 0 0 0 6 0 0 0 empty table cell 0 0 0 0 0 0 0 0 0 0 0 1.086 1.071 1.070 1.072 1.078 1.066 1.071 1.085 1.075 1.086 1.075 empty table cell 1.076 empty table cell empty table cell Harvested: September 17, 1999 (130 days). 2/5 sl. VD. Smooth, bright. 0/5 clean; nice yellow. 1/5 sl. VD. 0/5 smooth; uniform. 0/5 smooth white flesh. 1/5 HH. 0/5 clean, thin shape. 3/3 sl. VD; oval to oblong. 0/3 nice yellow. 0/5 med. red, nice yellow. 0 small. 1/2 sl. VD. empty table cell Table 7. 1999 SFA Chip Trial — V & G Farms Yiel d (cwt/A) Yiel d (cwt/A) Percent Size Distribution Percent Size Distribution Percent Size Distribution Percent Size Distribution No. 1 Entry NY112 410 358 W1313 344 ND2470-27 MSNT-1 328 317 MSA091-1 AF1668-60 296 274 ND2676-10 BO564-8 271 BO564-9 239 212 NY115 Snowden 196 AVERAGE 295 Total 438 418 431 395 360 322 364 307 269 256 237 345 No. 1 94 86 80 83 88 92 75 88 89 83 83 85 <2" 6 11 14 17 10 8 25 11 10 18 17 >3 1/4" 2-3 1/4" 22 72 83 3 69 11 3 80 19 69 4 88 2 73 11 77 24 65 6 76 6 77 empty table cell empty table cell empty table cell Comments 4/30 HH, 1/30 VD 3/30 HH, 1/30 BC Pick Percent Size Distribution Outs S.G. 1.073 1.091 1.071 Clean 1.081 1.079 1.077 1.071 1.068 1.064 1.066 1.082 empty table cell 1.075 empty table cell 1/30 HH 1/30 IBS 3/30 VD; 1/30 BC 1/30 BC 3/30 VD; 1/30 IBS 26/30 HH 1/30 VD; 1/30 IBS 3/30 HH; 2/30 VD 0 3 6 0 2 0 0 1 1 0 0 % Vine Maturity (8/30/99 15 15 60 85 80 95 100 90 90 95 50 empty table cell Table 8. empty table cell 1999 SFA Chip Quality Out of Field Samples 1/ Post Harvest Samples 2/ Post Harvest Samples 2/ Internal External Out of Field Samples 1/ SFA Score 1.5 1.5 2.0 1.5 1.5 2.0 2.5 2.0 2.5 2.0 1.5 Defect Comments Sl. SED, VD Scab, color, HH, VD SED, scab, VD Sl. SED, HH, color Sl. SED, VD, sl. color SED, color, sl. VD Sl. SED, VD, dark centers SED, HH, dark centers SED, HH, color, VD Color Sl. SED, VD, HH NY112 W1313 ND2470-27 MSNT-1 MSA091-1 AF1668-60 ND2476-10 BO564-8 BO564-9 NY115 Snowden l/ Samples collected at harvest on September 23 and chipped on September 24 at MSU Potato Processing Lab. SFA color score on acceptable chips only after defect chips were removed. SED = stem end discoloration, VD = vascular discoloration, HH = hollow heart. Post Harvest Samples 2/ Agtron Color 66.8 69.7 63.3 64.5 64.5 67.1 67.8 66.3 62.3 63.6 64.1 5.0 4.8 12.8 3.6 12.1 2.0 4.4 2.4 3.0 6.6 4.1 0 0 0.8 0 0 0 0 0 0 0 0 Post Harvest Samples 2/ Total 5.0 4.8 13.6 3.6 12.1 2.0 4.4 2.4 3.0 6.6 4.1 2/ Samples collected at harvest on September 23 and sent to Jays Foods, LCC in Chicago. Samples were processed and scored on September 29, 1999. Funding: MPIC Effect of Whole Seed Piece Weight, Planting Density and a Soil Stimulant on Yield in Commercial Seed Potato and Chip Potato Fields Brendan A. Niemira 1, William W. Kirk 2, Robert Schafer 2, Jeffrey M. Stein 2 and R. Scott Shaw 2 1 USDA-ARS-Eastern Regional Research Center, Food Safety Research Unit, Wyndmoor, PA 19038 Department of Botany and Plant Pathology, Michigan State University, East Lansing, MI 48824 Abstract Whole seed pieces were compared to cut seed pieces on commercial seed potato and chip potato farms. The seed piece weight and planting density were varied in the seed potato field and a mycorrhizal soil stimulant was applied to 2oz whole pieces and cut pieces in a separate treatment. Overall yields from 2oz seed pieces planted at 6" (36" row spacing) were not different between cut and whole seed, although whole seed tended to result in a higher proportion of smaller (<2oz) tubers in the seed potato field. Large seed pieces (6oz) and closer spacing (3") tended to increase yield per acre, but significantly decrease yield per pound of seed. Wider spacing (9") had no effect on yield per acre and significantly increased yield per pound of seed. Application of the soil stimulant had no significant effect on yields. Plot Designs Grower-initiated field trials of whole and cut seed were conducted on two separate commercial potato farms in Michigan. Potato seed pieces were planted and cultivated as per good agricultural practice. For test plots in both locations, Myconate was dissolved in water and applied as a soil drench to the base of the potato plant (cv. FL1833) once the plants had reached approximately 10" in height, before row closure. Dose rate was l0mg Myconate per plant. Growth and development of the canopy in treated and untreated plants was observed. At season’s end, potatoes were harvested, sorted by size and weighed. Seed potato field The trial examining planting density and seed size was conducted at lott Seed Farms, Kalkaska, ML The plots consisted of eight rows, 36" row spacing, 50' in length, four plots per treatment. The industry standard practice is to plant cut potato seed pieces weighing 2oz at 6" spacing in rows 36" apart. For this trial, three treatments examined whole seed weighing approximately 2oz, 3.5oz or 6oz, planted at 6" spacing. Two additional treatments examined whole seed pieces, 2oz, planted at 3" or at 9" spacing. Myconate was applied to plants arising from 2oz cut seed pieces and 2oz whole seed pieces using 6" spacing. The trial was hand-planted on May 18, Myconate was applied on June 23, and the four center rows of each eight-row plot were hand-harvested on September 17. The results of this study are in Fig. 1. The results of other treatments in the agronomic trial are presented in Fig. 2 and Fig. 3 for comparison. Chipping potato field A full-scale trial of whole seed vs. the industry standard of cut seed was conducted near Cass City, MI conducted by Walther Farms, Clio, MI. The overall trial covered 100 acres, 50 acres planted to 2oz cut seed pieces, 50 acres planted to 2oz whole seed pieces. Pieces were planted at 6" spacing, with 36" row spacing. The Myconate test plots consisted of eight rows, 50’ in length, four plots per seed type. The fields were machine planted on May 25, Myconate was applied to the plots on July 9 and plots were separately machine harvested, sorted and weighed by the grower in conjunction with the harvest of the rest of the field on September 27. The results of this trial are in Fig. 4. Results and discussion Overall yields from 2oz seed pieces planted at 6" (36" row spacing) were not different between cut and whole seed, although whole seed tended to result in a higher proportion of smaller (<2oz) tubers in the seed potato field (Fig. 2). Large seed pieces (6oz) and closer spacing (3") tended to increase yield per acre (Fig. 2), but significantly decrease yield per pound of seed (Fig. 3). Wider spacing (9") had no effect on yield per acre (Fig. 2) and significantly increased yield per pound of seed (Fig. 3). Yields from plants treated with the soil stimulant did not differ significantly from the industry standard practice at either test location. Planting of whole seed eliminates seed cutting as a preparation step. Also, tubers which are held intact are less susceptible to tuber rots (Erwinia carotovora and Fusarium sambucinum). In this study, cut seed was treated with a fludioxinil product (Maxim) immediately after cutting, and there were no differences in emergence percentage. The necessity for potato seed treatments may be reduced for seed that is not cut, however. The increase in yield per acre resulting from closer seed spacing or the use of large (3.5oz) or very large (6oz) whole seed pieces should be considered carefully in light of the increased seed requirements and seed handling costs. However, the increased proportion of small tubers may be of sufficient interest to a seed potato grower to warrant further investigation into the interaction of seed preparation and spacing. The authors wish to that lott Seed Farms, L. Walther and Sons, Inc., and VAMTech for support of this research. Mention of a product or brand name does not constitute an endorsement. Fig. 1. Whole vs. cut seed, myconate trials gross sample yields, 2oz pieces, 6" spacing Samples consisted of 200 row-feet, planted at 36" spacing, four plots per treatment. Myconate was applied as a soil drench when the plants were 10 inches high. Letters above a column indicate significant (P<0.05) difference from industry standard treatment (2oz cut pieces, 6" spacing) in TOTAL yield. Letters to the side of a column indicate significant difference from industry standard for yield of LARGE or SMALL tubers (see legend). Fig. 2. Whole vs. cut seed gross sample yields per acre (est.) Samples consisted of 200 row-feet, planted at 36” spacing, four plots per treatment. Yields per acre are estimated from the 200 row-foot samples. Letters above a column indicate significant (P<0.05) difference from industry standard treatment (2oz cut pieces, 6" spacing) in TOTAL yield (ANOVA, SNK). Letters to the side of a column indicate significant difference from industry standard for yield of LARGE or SMALL tubers (see legend). Fig. 3. Whole vs. cut seed sample yields per pound of seed Samples consisted of 200 row-feet, planted at 36" spacing, four plots per treatment. Yields per pound of seed are calculated based on the seed used for the entire 200 row-foot sample. Letters above a column indicate significant (P<0.05) difference from industry standard treatment (2oz cut pieces, 6“ spacing) in TOTAL yield (ANOVA, SNK). Letters to the side of a column indicate significant difference from industry standard for yield of LARGE or SMALL tubers (see legend). Fig. 4. Effect of Myconate on whole vs. cut seed, mechanically harvest chipping potato field Effect of cutting potato seed and the application of myconate on yield of potatoes (cv. FL 1833) in a comercial field operation (co-operator Walther Farms). Bars are sem (p = 0.05) no significant differences between treatments. Potato seed cutting and seed treatment application: agronomic effect of timing on plant emergence and tuber yield Funding: MPIC Brendan A. Niemira 1, William W. Kirk 2, Robert Schafer 2, Jeffrey M. Stein 2 and R. Scott 1: USDA-ARS- Eastern Regional Research Center, Food Safety Research Unit, 600 E. Mermaid Ln., Wyndmoor, PA, 19038; 2:Dept. Botany and Plant Pathology, Michigan State University, East Lansing, MI Shaw 2 48824. ABSTRACT In the second year of a two-year study, seed potatoes (cv. Onaway and Russet Burbank) were cut at different times: 180, 150, 120, 90, 60, 30, 10, 5, 2, 1 and 0 days before planting (DBP). A subset of these were treated with a fludioxinil-based seed treatment (Maxim) at the time of cutting, at the time of planting or left untreated. The plants were assessed for emergence, canopy development and yield. At the earliest cutting dates (180, 150, 120, 90 DBP), seed treatment at the time of cutting prevented reductions in biomass, emergence and yield seen in cohort seed treated at the time of planting or cohort seed left untreated. Date of chemical treatment was not a factor in later seed cutting dates. This variable response to the seed treatment date was not observed with R. Burbank. Although Onaway was more sensitive than R. Burbank to detrimental effects of very early seed cutting, immediate treatment of the cut seed negated these effects. Introduction Potato production in North America commonly includes the use of certified seed. This seed is frequently cut before planting to increase the plants set from each pound of seed. This practice can lead to the development of pathogens such as Fusarium dry rot (Fusarium sambucinum) and soft rot (Erwinia carotovora) in cut seed pieces. In deciding how far in advance to cut seed, growers must balance the time required to allow full suberization of the cut surface of the tuber with the danger of creating and maintaining an environment that may encourage pathogen development. An additional consideration is the management effort of a cutting operation in the period preceding planting. The logistical challenges of moving seed from controlled storage to a cutting operation site, back to storage and then to planting equipment are compounded by the increased use of potato seed treatments applied pre-planting. The most advantageous time to apply seed treatments, especially in relation to seed cutting, is not fully established. Seed treatments that suppress the development of seed-borne pathogens may counteract the negative consequences of a long delay between seed cutting and planting. The objectives of this experiment were to determine the effect on plant emergence, growth and tuber yield of a) varying delay between potato seed cutting and planting, b) varying timing of seed treatment application with respect to seed cutting, and c) varying late blight disease pressure (high and low). Materials and Methods Seed potatoes (cv. Onaway and R. Burbank) were held in storage, 42°F, 95% rel. humidity. Seed potatoes were cut by hand at 180, 150, 120, 90, 60, 30, 10, 5, 2, 1 and 0 days before planting. On each cutting date, 100 cut pieces were immediately treated with a fludioxinil-based seed treatment (0.5 lb/cwt) (Maxim, a product of Novartis) and placed in storage, 42°F, 95% rel. humidity, until the day of planting. On each cutting date, a separate group of 100 cut pieces were held in storage until the day of planting, and treated just before planting. On each cutting date, a separate group of 100 cut pieces were held in storage until the day of planting, and were planted with no seed treatment. On the day of planting, seed potatoes were cut, immediately treated and planted, while a separate group of seed potatoes were cut, planted, and the seed treatment applied in furrow over the cut pieces. Each treatment was hand planted with 25 seed pieces, and repeated 4 times. Treatments were examined for emergence and canopy development at 33 DAP. Canopy volume was calculated by an ellipsoidal approximation. The volume of an ellipsoid is derived as: V=(4/3)(π)(ABC), where A, B an C are the semiaxes of the ellipsoid. In a potato plant, A=plant height (h) and B=C=radius of plant at ground level (r). The volume of the individual plant is therefore derived as: Vplant=(4/3)(π)(hr2). The average plant estimation is derived from and average of the two largest and the two smallest emerged plants. Total treatment canopy volume is the average single plant volume for each treatment multiplied by the number of emerged plants. Tubers were harvested and yields were recorded. Dta were examined with one-way analysis of variance (ANOVA). Results There were significant difference between the different cutting dates. For Onaway, the earliest cutting dates were generally detrimental to biomass (Fig. 1) and emergence (Fig. 2). Seed treatment at the time of cutting alleviated this, relative to cohort seed that was left untreated, or stored untreated until the day of planting. Reduced biomass and emergence resulted in reduced yield for these treatments (Fig.3). Later cutting dates did not show significant differences. For R. Burbank, there were no significant differences between earlier and later cutting dates in biomass (Fig.4), emergence (Fig.5) or yield (Fig.6). When yield data is combined by the date of cutting (Fig. 7), R. Burbank shows a slight trend toward increased yield as the interval between cutting and planting decreases. Onaway shows no clear pattern. Yield data combined by the date of treating (including those seed pieces left untreated, Fig. 8), does not show a clear pattern for either variety. Discussion In this study, Onaway was more sensitive to detrimental effects of very early cutting than was R. Burbank. Application of the chemical seed treatment was effective at reducing this negative impact for seed cut very early, but had no clear effect on seed cut closer to the date of planting. In general, variability in results was more pronounced for seed cut earlier than later. Under commercial seed storage conditions, this variability may be a primary factor in how early seed cutting and/or treatment is implemented. Mention of a product and/or brand name does not constitute an endorsement. Fig. 1. Total biomass in row under various cutting/treating patterns (33 DAP): ONAWAY Fig. 2. Emergence (%) under various cutting/treating patterns (33 DAP): ONAWAY Fig. 3. Yield under various cutting/treating patterns: ONAWAY Trials conducted at MSU’s Montcalm Potato Research Farm, 1999. Bars indicate standard deviation, n=4. Fig. 4. Total biomass in row under various cutting/treating patterns (33 DAP): R. BURBANK Fig. 5. Emergence (%) under various cutting/treating patterns (33 DAP): R. BURBANK Fig. 6. Yield under various cutting/treating patterns: R. BURBANK Trials conducted at MSU’s Montcalm Potato Research Farm, 1999. Bars indicate standard deviation, n=4. Fig. 7. Yield, average by cutting date (treating dates combined) Trials conducted at MSU’s Montcalm Potato Research Farm, 1999. Bars indicate standard deviation, n=4. Fig. 8. Yield, average by treating date (cutting dates combined) Trials conducted at MSU’s Montcalm Potato Research Farm, 1999. Bars indicate standard deviation, n=4. 1999 POTATO NEMATODE RESEARCH REPORT GEORGE W. BIRD, PROFESSOR OF NEMATOLOGY DEPARTMENT OF ENTOMOLOGY MICHIGAN STATE UNIVERSITY The 1999 MP1C-MSU Potato Nematode Research Report consists of a summary of the results of four projects: 1) two nematicide trials funded jointly by MPIC, MSU and agribusiness; 2) potato cultivar/line and glucose-oxidase transgenic line evaluation for resistance/tolerance/susceptibility to plant-parasitic nematodes and the potato early-die disease complex funded jointly by USDA and MSU, 3) long-term potato farming systems research for development of alternative potato nematode and potato early-die disease complex management tactics funded jointly by MPIC and MSU; and 4) precision agriculture research for nematode and potato early-die disease complex management, funded jointly by MPIC and MSU. The report consists of descriptions of the projects, project results, key findings and new references of significance.. 1999 Nematicide Trials - Two nematicide trials were conducted at the Montcalm Potato Research Farm. The first trial used the potato variety Pike and was designed to evaluate various fumigant and non-fumigant nematicides in relation to tuber yield and quality responses and nematode population suppression. It consisted of eight treatments (five fumigant and three non- fumigant) and an associated check (Table 1). The research site was infested with both root-lesion and northern root-knot nematodes. The highest total, A-size and jumbo-size tuber yields were associated with metham pre-plant soil injected at 75 gallons per acre in a 3:1 water to product mixture. The second nematicide trial involved the potato variety Snowden and was part of the first year of the Montcalm Potato Research Farm Precision Agriculture Initiative. Metham was used on a pre-plant soil injection basis at 75 gallons per acre in a 3:1 water to product mixture. The site was infested with a low population density of root-lesion nematode. Excellent nematode control was obtained in addition to a tuber yield response of 125 to 175 cwt per acre (Table 2). Key Findings: 1. Temik 15 G is an excellent nematicide for control of root-lesion nematodes. It is not, however, as good a nematicide for management of northern root-knot nematodes. 2. Recent FQPA information indicates that most Mocap used in potato production in the west is applied at 90 lbs per acre. This is in agreement with MSU research. 3. Proper application of metham is essential for optimal benefits from this material. It must be mixed with at least 3 parts water to 1 part product for the 37.5 gallon per acre to provide consistent nematode control and tuber yield response. 4. Vydate 2L can be phytotoxic when it is applied on an at-plant basis with poor quality seed. 5. The 1,3-D component of Telone C-35 is essential for optimal nematode control and tuber yield response. Telone C-35 applied in-row at 6 gallons per acre is not adequate under Michigan conditions. Potato Cultivar/Line Evaluation for Resistance/Tolerance/Susceptibiiity to Nematodes and the Potato Early-Die Disease Complex.- 1999 was the third year of the potato nematode/early- die component of the USDA Project. During the first years, twenty-two potato lines/varieties were field evaluated in relation to their susceptibility/tolerance/resistance to potato nematodes and the early-die disease complex. Definitions for these terms are provided in Table 3. Twenty-five lines/cultivars were evaluated in 1999 (Table 4). The evaluation criteria used in 1999 are those developed at MSU for evaluation of resistance and tolerance in soybean lines to the soybean cyst nematode. Four data points, relative yield in nematode-infested soil, tolerance index, relative yield in fumigated soil and a PED index are reported for each line/cultivar. One line (MSG 050-2) was identified as having possible resistance to the root-lesion nematode (Table 5). The other lines and cultivars were identified as tolerant, having possible tolerance or susceptible. In general, there was excellent agreement between the 1998 and 1999 evaluations. It is recommended that this work not only continue, but that formal breeding for root-lesion and northern root-knot nematode resistance be added to the program. The interactive literature database of potato germplasm with known resistance, tolerance and susceptibility to Pratylenchus spp., Meloidogyne spp., Verticillium spp., Ditylenchus destructor, Globodera rostochiensis and G. pallida was completed in 1998 and maintained and updated throughout 1999. It can be accessed at Http://nematode.ent.msu.edu/nematology. Microtubers of Spunta, SGO-1, SGO-3 and SGO-9 were planted at the Montcalm Potato Research Farm in 1999 and subjected to one of the following four treatments (1. Root wounding plus inoculation with Verticillium dahliae, 2. root wounding, 3. inoculation with V. dahliae, or a non-disturbed. SGO-3 emergence was very slow and tuber yields were low compared to the other three lines. No significant differences were observed among the treatments or the other three lines. Key Findings. 1. MSU Nematology Program definitions for resistance, tolerance and susceptibility have been formalized. 2. The potato nematode resistance website is being maintained and updated. 3. A significant number of lines and cultivars have been identified with potential resistance or tolerance to the root-lesion nematode. 4. A series of transgenic lines have been evaluated. 5. It is being recommended that the program be expanded to include formal breeding for resistance to root-lesion and northern root-knot nematodes. 1991-2000 Potato Farming Systems Trial.- The year 2000 is scheduled as the tenth and final year for the Long-Term Farming Systems Trial (Table 6). Because of the potential future value of the site, there appears to be significant interest in maintaining it for an additional period of time. During the past decade the plant parasitic nematode problem associated with the site has changed from one dominated by the root-lesion nematode to several farming systems that have high population densities of the northern root-knot nematode (Table 7). In 1999, Russet Norkotah tuber yields were once again highest in the two-year alfalfa conventional farming system (Table 8). For the past three years, the root-lesion nematode resistant alfalfa variety WL 252HQ, has been used, resulting in the lowest end-of-season population density of this nematode (Table 9). Corn, wheat, buckwheat and the two-year alfalfa system suppress population densities of the northern root-knot nematode. The buckwheat and the two-year alfalfa systems are the only ones that suppress both root-lesion and the northern root-knot nematodes. A summary of expected nematode control is presented in Table 10. The project is also evaluating responses of other types of nematodes and microbes to the different farming systems. For example, at-harvest population densities of bacterial feeding nematodes are highest following wheat and buckwheat compared to the other potato farming systems. At- harvest population densities of fungivores were low, and the highest levels of omnivores were associated with alfalfa. The highest population densities of endomycorrizal spores were recovered from the conventional continuous potato system and following two years of com. Population densities of both oligocheates and carnivorous nematodes were relatively low. Key Findings. 1. When corn and wheat are removed from potato production systems in sandy soils, there is a high probability that it will result in development of a northern root-knot nematode problem. Although these crops are good hosts for root-lesion nematodes, they are very valuable in suppressing northern root-knot nemtodes. 2. Root-lesion nematode resistant alfalfa provides excellent suppresion of this nematode. After two years of growth, associated population densities of the northern root-knot nematode are relatively low. 3. Buckwheat is a poor host of both the root-lesion and northern root-knot nematodes. 4. The project resulted in a major conceptual change in thinking, evolving from a rotation crop to a potato farming system concept. 5. The significance of soil quality in relation to nematode problems and nematode management developed directly from this project. 6. Several aspects of the award winning publication entitled “Michigan Field Crop Ecology” and the associated education programs would not have been possible without this farming system project experience (MSU Extension Bulletin E-2646).. 7. It is anticipated that a new publication entitled, “Michigan Field Crop Pest Ecology and Management” will be available for distribution before the end of the MPIC Research Committee Meeting. The overall philosophy of this book is that “If the grower knows why, he will teach himself how (Liberty Hyde Bailey, 1916)”. Many aspects of the chapter entitled “Nematodes and Soil Quality” are based on the findings and experiences associated with this project (MSU Extension Bulltein E-2704). 8. The idea of the importance and urgent need for root-lesion and northen root­ knot nematode resistant potato varieties evolved from experiences associated with the long-term potato farming systems trial. Precision Agriculture/Potato Nematode Projects - It has been known for at least 25 years that populations of plant parasitic nematodes are distributed in fields in a clumped or aggregate manner. For the past two decades that MSU Extension Nematology Program has recommended that a stratified system be used for collection of soil and root tissue samples for nematode analysis. In general, this has not been possible because the lack of appropriate geo-referencing and associated data-base technology. 1999 was the first year that the MSU Nematology Program formally participated in potato research activities under the heading of Precision Agriculture. Two projects were initiated, one at the Montcalm Potato Research Farm and the other at Anderson Brothers. The current objective of the Montcalm project is to geo-reference and characterize three research ranges: with special reference to calcium and nematode management. This work is being done jointly with Dr. Warncke and Dr. Brook. It will be recommended that the project be expanded to geo-referencing and characterizing the entire research farm, as a prototype project for MSU Land Management. The second project is being conducted at an Andersen Brother Farm in Vestaberg, Michigan. This is being done jointly with Dr. Brook, Dr. Warncke and Mark Otto of Agribusiness Consultants. The nematode component of one 62.1 acre site was characterized in 1999 and the results being used for year 2000 management decisions. Other precision agriculture nematology research is being conduct in carrot and soybean production systems. It is anticipated by sugar beets will be added to the list in the near future. Initial Findings. The technologies of precision agriculture appear to be ideal for: 1) characterization of field population of plant parasitic nematodes, 2) identification of specific locations of low yields associated with nematode problems, and 3) use in the implication of variable tactic/rate nematode management procedures. New References of Significance to Potato Producers.- Michigan Field Crop Ecology (1998). MSU Extension Bulletin E-2646. 86 pp. This very well illustrated and award winning publication contains information about nitrogen, carbon, covercrops, nematodes, insects, soil ecology, pest management and the principles of ecology. The book was designed and written based on needs identified by Michigan farmers. Prior to publication, the initial draft of the book was reviewed in a public hearing, and then the final draft evaluated by selected Michigan farmers. Michigan Field Crop Pest Ecology and Management (2000). MSU Extension Bulletin E-2704. 102 pp. This recently published book contains new and innovative ways of presenting information about the ecology and management of weeds, insects, and plant pathogens. It also contains chapters about soil ecology and how nematodes relate to soil quality. The book uses case studies of three Michigan farms as reference points for discussion. It also contains lists and evaluations of key management practices. Table 1. 1999 Potato Nematicide Trial (Montcalm Potato Research Farm). Treatment Tuber yield (cwt) Stand (50 ft) Nematodes 1 (100 cm3 soil) Total Tuber yield (cwt) A size Tuber yield (cwt) Jumbo Control Metham (37.5 gal/A) Metham (75 gal/A) Telone II (12 gal/A) Telone C-35 (12 gal/A) Telone C-35 (6 gal/A) Temik 15G (20 lbs/A) Mocap 10G (30 lbs/A) Vydate 2L (2 gal/A) ANOVA 359abc 387bc 455c 406bc 306a 319a 390a 348a 322ab 273a 292ab 382bc 382a 238a 243a 330a 330a 190a 21a 41b 41b 33b 24a 19a 20a 20a 28ab 69bc 65bc 68bc 60b 59b 53ab 63bc 76c 38a 706 3 5 8 5 331 23 50 337 <0.01 <0.01 <0.01 <0.01 0.081 1 Root-lesion and northern root-knot nematodes (7/21/1999) Table 2. 1999 Montcalm Potato Research Farm Precision Agriculture Trial tuber yields and mid­ season nematode population densities. Treatment Control Gypsum Metham (75 gal/A) Metham (75 gal/A) & Gypsum Tuber yield (Cwt/acre) Root-lesion nematodes (No. per 1.0 g root tissue) 255.3 a 297.7 a 430.6 b 422.5 b 11.7 a 60.0 b 0.00 a 0.00 a Table 3. Nematology definitions for host plant resistance, tolerance and susceptibility. Resistance: Cultivars/lines containing genes that prevent nematodes from entering roots, reproducing and causing significant yield losses are known as resistant varieties/lines. With some crops, genes for resistance provide resistance to only a limited number of races of a specific nematode. If a single source of resistance is used in a location for a long period of time, it is possible for composition of a race complex to change and the resistance to break down. Tolerance: Cultivars/lines that allow nematodes to invade roots and reproduce without causing significant yield loss are known as tolerant varieties/lines. Tolerance can be an important tool for use in nematode management. It can be used to reduce selection pressure associated with the break kown of resistant cultivars. Susceptibility: Cultivars/lines that allow plant pathogenic nematodes to invade roots, reproduce and cause significant crop yield losses are known as susceptible varieties/lines. Rotation of susceptible and resistant varieties can be used to decrease risk associated with the break down of resistant varieties/lines. Table 4. 1999 Potato Early-Die Resistance/Tolerance/Susceptibility Research Line/Variety Relative Yield (Infested soil) Tolerance index Relative Yield (Fumigated soil) PED Index (0.0-5.0) Superior MSB 106-7 MSE 192-8 MSE 149-5Y MSN 4-T MSF 099-3 Atlantic MSA 091-1 MSG 227-2 Onaway MSB 107-1 Russet Norkotah Russet Burbank MSE 226-4Y MSE 246-5 MSE 228-11 MSE 048-2Y MSE 018-1 Snowden Reddale MSE 228-1 MSE 033-1 MSG 050-2 MSG 274-3 MSF 373-8 0.56 0.44 0.39 0.68 0.62 0.51 0.57 0.47 0.28 0.66 0.46 0.38 0.30 0.52 . 0.55 0.95 0.51 0.75 0.51 0.77 0.70 1.00 0.79 0.50 0.36 0.67 1.09 0.75 0.78 0.75 0.72 0.78 0.67 0.56 0.71 0.65 0.75 0.61 0.69 1.23 1.19 0.65 0.96 0.72 0.92 0.89 0.93 1.09 0.50 0.83 0.79 0.38 0.50 0.82 0.78 0.67 0.69 0.67 0.48 0.87 0.67 0.49 0.48 0.71 0.77 0.42 0.74 0.73 0.67 0.78 0.71 1.00 0.68 0.93 0.40 5.00 4.25 3.23 3.25 2.75 2.50 3.00 2.75 3.25 3.75 1.25 4.00 3.25 2.25 2.75 3.00 2.00 ---- 2.75 3.00 2.50 4.25 4.00 2.75 1.67 Table 5. Summary of the results of the 1997-1998 Potato Early-Die and Nematode Tolerance/Resistance Research. 1997. Possible Tolerance Chieftain empty table cell empty table cell empty table cell empty table cell empty table cell 1998 Possible Resistance F349-1RY empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1999 Possible Resistance MSG 050-2 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1997. Susceptible Atlantic Onaway Russett Burbank Russet Norkotah Shepody Snowden empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell Possible Tolerance 1998 E226-4Y E228-1 E-228-11 F373-8 G104-6 G119-1R MSB107-1 1 E048-2Y1 Chieftain 1998 Susceptible E018-1 F-313-3 E149-5Y Russett Burbank Reddale Shepody Superior empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell Inconclusive 1998 B107-1 C103-2 E026-B E030-4 E033-1RD empty table cell empty table cell empty table cell empty table cell 1999 Tolerance Reddale MSE 228-11 1 MSE018-1 MSE-228-1 MSE 033-1 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell Possible Tolerance 1999 MSB 106-7 MSE 246-5 MSF 337-8 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1999 Susceptible Superior 2 MSE 192-8 MSE 149 5Y MSN 4-T MSF 099-3 Atlantic MSA 091-1 MSG 227-2 Onaway MSB 107-1 Russet Norkotah Russet Burbank MSE 226-4Y MSE 048-2Y Snowden MSG 274-3 'Tolerant cultivars/lines in boldface were evaluated in both 1998 and 1999. Susceptible cultivars/lines in boldface yield exceptional well in fumigated soil. Table 6. Description of the crops and soil nutrition programs used in a 10-Year Farming System - Nematode Management Research Project (1991-2000) at the Montcalm Potato Research Farm in Entrican, Michigan. Farming System 1 2 3 4 5 6 7 8 9 10 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Potato Rye1 Alfalfa1 Oats Rye1 Oats Rye1 Oats Rye1 Oats Rye1 Oats Rye1 Oats Rye1 Oats Rye1 Oats Rye1 Potato Rye1 Potato Rye1 Alfalfa1 Potato Rye1 Potato Rye1 Potato1 Alfalfa1 Alfalfa1 Potato Rye1 Soybean Rye1 Soybean Rye1 Soybean Rye1 Soybean Rye1 Soybean Rye1 Potato Rye1 Alfalfa1 Light red kidney beans, Rye1 Light red kidney beans, Rye1 Light red kidney beans, Rye1 Light red kidney beans, Rye1 Potato Rye1 Potato Rye1 Potato1 Potato Rye1 Potato Rye1 Alfalfa1 Alfalfa1 Potato Rye1 Hairy vetch1 Nematode mix1 Alfalfa1 Annual rye grass1 Potato Rye2 Alfalfa1 Potato Rye1 Potato Rye1 Oats1 Alfalfa1 Oats/Red Clover1 Alfalfa1 Potato Rye1 Potato Rye1 Buckwheat Rye1 Potato Rye3 Potato Rye1 Potato Rye1 Alfalfa3 Alfalfa3 Potato Rye1 Potato Clover1 Potato Clover3 Alfalfa1 Wheat Clover1 Potato Alfalfa1 Alfalfa1 Green pea1 Oil seed radish1 Potato Rye1 Oilseed radish Rye3 Corn Clover1 Potato Rye1 Wheat Clover1 Potato Rye3 Alfalfa1 Potato Potato Rye1 Corn Clover1 Potato Rye3 Potato Alfalfa1 Wheat Alfalfa1 Alfalfa1 Potato Alfalfa1 Alfalfa1 Corn Potato Green pea1 Potato Rye2 Oil seed radish1 Potato Rye1 Buckwheat Clover3 Potato Clover3 Buckwheat Clover3 Green pea1 Buckwheat 2 Potato Rye1 Buckwheat Rye3 Potato Clover3 Buckwheat Clover3 Potato Clover3 1 Conventional soil nutrition program. 2 30 T/A cow manure compost. 3 Alternative soil nutrition program. Farming System Descriptions: Continuous Potato (No. 1 and No. 3) Potato-Wheat-Rye Rotation (No. 2, No. 5, and No. 8) 2-year Alfalfa-Potato (No. 4, No. 6, No. 7) Buckwheat-Potato (No. 9 and No. 10) October 20,1999 Table 7. 1999 mid-season population densities of root-lesion and northern root-knot nematodes recovered from root tissue associated with ten potato farming systems at the Montcalm Potato Research Station. Farming System (1999 crop) Nematodes per 1.0 gram root tissue Root lesion Root-knot Nematodes per 1.0 gram root tissue Nematodes per 1.0 gram root tissue Total 1. Continuous potato-c (Potato) 120 cd 2. Wheat/corn/potato-c (Wheat) 86 bcd 3. Continuous potato-a (Potato) 138 d 4. 2nd-year alfalfa-c (Alfalfa) 40 ab 5. Wheat/corn/potato-c (Potato) 129 d 6. lst-year alfalfa-c (Alfalfa) 7. Potato/alfalfa-c (Potato) 46 ab 37 ab 8. Wheat/corn/potato-c (Corn) 61 abc 9. Potato/buckwheat-a (Potato) 74 bcd 10. Potato/buckwheat-a (Buckwheat) 2.5 a 636 b 14 a 506 b 55 a 60 a 26 a 144 a 14a 61 a <1 a 756 b 100 a 644 b 95 a 189 a 73 a 181 a 75 a 146 a 1.6 a Table 8. Relative potato tuber yields associated with a Ten-Year Farming System/Nematode Management Research Project at the Michigan State University Montcalm Potato Research Farm in Entrican, Michigan. Farm system 1 2 3 4 5 6 7 8 9 Oats2 Soybean2 Oats2 Soybean2 10 Oats2 Soybean2 Crop 1991 Potato2 Alfalfa2 Alfalfa2 Oats2 Oats2 Oats2 Oats2 1992 Crop Potato2 Potato2 Crop 1993 Potato2 Potato2 Alfalfa2 Potato2 Alfalfa2 Potato2 Soybean2 Soybean2 Alfalfa2 Potato2 Alfalfa2 Light red kidney beans2 Light red kidney beans2 Light red kidney beans2 Light red kidney beans2 Crop Potato2 Crop 1994 Potato2 Potato2 1995 Potato2 Hairy vetch2 Nematode tri-mix2 Alfalfa2 Annual rye grass2 Alfalfa2 Potato2 Alfalfa2 Alfalfa2 Potato2 Potato2 Crop 1996 Potato2 Potato2 Oats2 Alfalfa2 Oats/Red clover2 Alfalfa3 Potato2 Green peas2 Oil seed radish3 Potato2 Green peas2 Potato3 Oil seed radish3 Crop 1997 Potato2 Buck­ wheat3 Potato4 Potato2 Potato2 Alfalfa4 Alfalfa4 Oil seed radish4 Potato2 Green peas2 Buck­ wheat3 Potato2 Buck­ wheat4 Crop Crop 1999 1998 Potato2 Potato2 Potato2 Wheat2 Potato4 Potato4 Alfalfa2 Wheat2 Potato2 Alfalfa2 Alfalfa2 Potato2 Alfalfa2 Potato2 — Corn 2 Corn2 — Buck­ wheat4 Potato4 Potato4 — Buck­ wheat4 — Relative Yield, U.S. No. 1 Potato Tubers 1 Relative Yield, U.S. No. 1 Potato Tubers 1 1991 Relative Yield, U.S. No. 1 Potato Tubers 1 1.00 — Relative Yield, U.S. No. 1 Potato Tubers 1 Relative Yield, U.S. No. 1 Potato Tubers 1 1992 0.69 1.00 1994 0.29 0.34 1993 0.34 0.54 1995 0.79 — 1996 0.87 0.95 Relative Yield, U.S. No. 1 Potato Tubers 1 Relative Yield, U.S. No. 1 Potato Tubers 1 1997 0.45 — Relative Yield, U.S. No. 1 Potato Tubers 1 1998 0.61 0.77 Relative Yield, U.S. No. 1 Potato Tubers 1 1999 0.33 — — — — — — — 0.97 — 1.00 — 0.53 — — — — — — — — — — — — — 0.57 1.00 0.32 — — — — 1.00 — — — — — 1.05 1.00 0.88 — — 1.00 — — 1.14 — 0.93 — 0.97 0.33 — — 1.00 — — 0.56 — 0.74 — 1.00 — 0.56 — 1.35 — 0.86 — 1 Relative yields calculated by assigning a yield of 1.0 to the standard farming system (2 years of alfalfa followed by one year of potato) and dividing the U.S. No. 1 tuber yields for each farming system by the U.S. No. 1 tuber yield for the standard. The two exceptions were in 1991 and 1992, where the U.S. No. 1 tuber yields for the only potato system and the potato system following a single year of alfalfa were used as the standard, and in 1996 and 1997 when situations of over-yielding existed. 2 Conventional potato production soil nutrition program. 3 Application of 30 T/A of cow manure compost. 4 Alternative potato production soil nutrition program. Table 9. 1999 At-harvest population densities of root-lesion, northern root-knot and ring nematodes recovered from 100 cm3 soil associated with ten potato farming systems at the Montcalm Potato Research Station. Farming System (1999 crop) Nematodes per 100 cm3 soil Nematodes per 100 cm3 soil Root lesion Root-knot Nematodes per 100 cm3 soil Ring 1. Continuous potato-c (Potato) 2. Wheat/corn/potato-c (Wheat) 29 a 66 c 3. Continuous potato-a (Potato) 34 ab 4. 2nd-year alfalfa-c (Alfalfa) 5. Wheat/corn/potato-c (Potato) 6. lst-year alfalfa-c (Alfalfa) 7. Potato/alfalfa-c (Potato) 8. Wheat/corn/potato-c (Corn) 14 a 63 c 19a 27 a 24 a 9. Potato/buckwheat-a (Potato) 59 bc 10. Potato/buckwheat-a (Buckwheat) 34 ab 349 bc 39 a 395 cd 33 a 91 ab 181 ab 589 d 14a 208 abc 27 a 0a 26 a 11 a 80 b 8a 143 c 25 a 1 a 1 a 1 a Table 10. Pratylenchus penetrans (root-lesion nematode and Meloidogyne hpala (northern root­ knot nematode management summary for potato production. Procedure Expected nematode control 1 Expected nematode control 1 Root lesion nematode Northern root-knot nematode Metham (75 gal/A) Metham (37.5 gal/A) Telone II (12 gal/A) Mocap 10G (9.0 lbs a.i./A) Temik 15G(3.0 lbs a.i./A) Vydate 2L (2.0 gal/A) Alfalfa (2-year rotation) Oilseed Radish (green manure) Mocap 10G (3.0 lbs a.i./A) Buckwheat (rotation crop) Wheat (rotation crop) Corn (rotation crop) Peas, green beans, pickles, dry beans, soybeans, and carrots (rotation crops) 99% 90% 90% 80% 80% 75% 75% 70% 70% 50% 0% 0% 0% 95% 85% 85% 80% 70% 85% 75% 70% 70% 90% 90% 90% 0% 1 Expected potato nematode control estimates based on comparative mid-season potato root population densities of the penetrans root-lesion and northern root-knot nematodes. Funding: Fed. Grant/MPIC/GREEEN/Indus Insect Management in Potatoes 1999 Research Report Beth Bishop, Adam Byrne, John Lekovish, David Mota-Sanchez, Haddish Melakeberhan, Nathan Cottrell, Walter Pett, Chang-hui Rui, Robert Hollingworth, Mark Whalon, and Edward Grafius Department of Entomology and Center for Integrated Plant Systems Michigan State University. Summary: During the 1999 growing season, Colorado potato beetle populations in most of Michigan were low to moderate. Aphid and potato leafhopper numbers were also reported as moderate. Admire ® and Provado® (imidacloprid, Bayer Corp.) continued to provide adequate control of Colorado potato beetle and aphids. Fulfill (Novartis Corp) received federal registration late in the year, and should provide good control of aphids in future years. During 1999, our research focused again on resistance to Admire® (imidacloprid) in the Colorado potato beetle. Objectives included: 1) surveying Colorado potato beetle field populations for resistance to Admire®, thiamethoxam, (Novartis Corp) and previously-used insecticides, 2) determining how fast the level of resistance to imidacloprid increases in response to selection pressure, 3) studying how resistance to imidacloprid is inherited, and 4) evaluating the influence of synergists on imidacloprid toxicity to determine possible mechanisms of resistance. We also continued our studies of biological control of Colorado potato beetle. We evaluated the effect of imidacloprid use on biological control by examining the interaction between imidacloprid poisoning in Colorado potato beetles and predation by ground beetles. We also began a new project to assess the potential for biological control of Colorado potato beetle with entomopathogenic nematodes and Beauvaria bassiana,. Finally, we conducted several insecticide trials to determine the efficacy of registered and experimental insecticides for control of Colorado potato beetle and potato leafhopper. Bioassays of Colorado potato beetle populations collected throughout Michigan and some out-of-state locations yielded LD 50 values for imidacloprid that were similar to those obtained in previous years. Artificial selection with imidacloprid in the laboratory increased the resistance of Michigan potato beeties, but did so slowly; after six generations of selection, beetles were only 1.7 times more resistant than the original population. Studies conducted in 1998 and 1999 indicate that resistance to imidacloprid in the Colorado potato beetle is inherited autosomally as a recessive trait. These results collectively support the idea that, in most cases, resistance to imidacloprid develops slowly, at least at first. Methods to manage and reduce the risk of resistance development may be more successful for imidacloprid than for some other insecticides. Populations collected from Long Island, NY expressed higher levels of resistance compared with susceptible, Michigan and upstate NY populations. Bioassays of slightly resistant and highly resistant Colorado potato beetles with the synergist piperonyl butoxide indicate that mixed function oxidases are an important mechanism, though not the only mechanism for resistance to imidacloprid. LD 50 values for thiamethoxam were significantly correlated with LD 50 values for imidacloprid in Colorado potato beetle populations for the second year in a row, indicating the strong possibility of cross resistance. Petri dish resistance test kits revealed that resistance to Furadan, Imidan and Thiodan is still present, to a substantial degree, in most Michigan Colorado potato beetle populations, even though these insecticides have been rarely used since 1995. Biological control studies indicate that imidacloprid-poisoned Colorado potato beetles may be preyed upon in the field. Predatory ground beetles that consume poisoned potato beetles sometimes show signs of imidacloprid poisoning. More research is needed to determine the precise influence of imidacloprid treatment on predation. Both entomopathogenic nematodes and the fungal disease Beauveria bassiana show promise as biocontrol tools for Colorado potato beetle. Admire (imidacloprid) resistance in Colorado potato beetle Imidacloprid, (Admire®, Provado®, Bayer Corp.) a neonicotinyl insecticide, was first registered for use on potatoes in 1995. It immediately became the primary means to control organophosphate, pyrethroid and carbamate-resistant Colorado potato beetles in Michigan and other areas of the U.S. (Grafius, 1997). Because Colorado potato beetle has demonstrated an ability to evolve resistance to virtually any insecticide used to control it (Bishop and Grafius 1996), and because imidacloprid is so widely used, concerns about development of imidacloprid resistance in Colorado potato beetle have been present ever since. In 1997, low levels of resistance were detected in a Michigan Colorado potato beetle population. That same year a population from Long Island, NY was found to be 100-fold more resistant than susceptible populations (Zhao et al. in press). On Long Island growers experienced reduced potato beetle control in many fields, indicating that the efficacy of imidacloprid against Colorado potato beetie has declined in that area (MacNeil 2000). We began to investigate the potential development of imidacloprid resistance in the Colorado potato beetle in 1995 and have continued that research each year. The insecticides used in this study included imidacloprid (98.7%, technical grade), provided by Bayer (Kansas City MO), piperonyl butoxide (90%, technical grade), supplied by Aldrich Chemical Company, Inc., and piperonyl butoxide, (98% technical grade), provided by Chem Service, West Chester, PA. Survey of resistance in field populations of Colorado potato beetle Once again we assessed the level of imidacloprid resistance in field-collected Colorado potato beetle populations from Michigan and other locations. Many of these populations were also assessed for their susceptibility to thiamethoxam, another neonicotinyl insecticide (Novartis Corp.) that may be registered soon for use on potatoes. Finally, to determine if several years without exposure to previously-used (1995 and earlier) insecticides would reduce resistance to these insecticides, several field-collected populations were tested using the petri dish resistance test kit (Bishop and Grafius 1991). Two different studies were conducted. In the first study, nine Colorado potato beetle populations were collected from seven different Michigan counties (Kent, Midland, Montcalm, Mecosta, Delta, Houghton, and Berrien). Cooperators also sent us populations from Maine, Wisconsin, Minnesota, and New York. Five of the Michigan populations, four out-of-state populations, and one highly resistant laboratory population collected from Long Island, NY in 1997, were tested for resistance to both imidacloprid and thiamethoxam. Colorado potato beetle adults were either stored at room temperature (25±1°C) and fed foliage daily or, for long term storage, were kept in a controlled environment chamber (11±1°C) and fed weekly. Before each bioassay, potato beetles were combined and randomly assigned to treatments. Beetles were treated with 1 pl of a known concentration of acetone/insecticide solution applied to their abdomen. After treatment, beetles were placed in petri dishes lined with filter paper and provided with fresh potato foliage. The petri dishes were stored at 25±1°C and the foliage and filter paper were checked daily and changed as needed. Each population was first screened to determine their relative susceptibility to imidacloprid and thiamethoxam; three concentrations of insecticide/acetone solution plus an acetone-only control were applied to 10 beetles each. Based on results of this screen, a range of five concentrations, plus an acetone control, was selected for each population. Each bioassay was replicated up to three times using serial dilutions prepared on different dates. Within each bioassay, from 12-15 beetles were treated with each concentration (4- 5 beetles per dish and 3 dishes per concentration). The responses of the beetles were assessed 7 and 10 days after treatment. A beetle was classified as dead if its abdomen was shrunken, it did not move when the legs or tarsi were pinched, and its elytra were darkened. Dead beetles were removed from the dish. A beetle was classified as walking if it was able to grasp a pencil and walk forward normally. A beetle was classified as poisoned if the 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. Probit analyses were conducted on all data obtained using Polo PC© statistical software. The LD50 values for imidacloprid at 7 and 10 days after treatment did not vary significantly between populations (overlapping 95% confidence limits) (Table 1). LD50’s 7 days after treatment ranged from 0.039 μg (Mecosta 1) to 0.070 μg (Kent) for Michigan populations. This is similar to the range of LD50 values found for Michigan potato beetle populations in 1998. The LD50 ‘s for out-of-state populations ranged from 0.029 pg (Maine) to 0.102 μg (Upstate New York). Basically, these values correspond to levels of insecticide resistance generally found in these areas, and are very similar to the values found in 1998. As with imidacloprid, the LD50 values for thiamethoxam did not vary significantly between populations (overlapping 95% confidence limits) (Table 2). For Michigan populations, LD50 ‘s 7 days after treatment ranged from 0.059 μg (Mecosta 1) to 0.124 pg (Kent). This is similar to the range of LD50 valuess found for Michigan potato beetle populations in 1998. The LD50 ‘s for out-of-state populations ranged from 0.045 pg (Maine) to 0.101 pg (Upstate New York). In general, the LD50 values for thiamethoxam in 1999 were slightly higher than those obtained in 1998. However, once again the relative resistance to imidacloprid (as measured by LD50) in Colorado potato beetle populations was significantly correlated with the relative resistance to thiamethoxam. Populations with the highest LD50 values for imidacloprid also had the highest LD50 values for thiamethoxam. Correspondingly, populations with the lowest LD50 ‘s for imidacloprid also had the lowest LD50 ‘s for thiamethoxam. Table 1. LD50’s (μg per beetle) for Colorado potato beetle populations treated with imidacloprid 7 and 10 days after treatment. 7 days after treatment 7 days after treatment 95% C.L. LD50(μg) ___ 10 days after treatment 10 days after treatment 95% C.L. LD50(μg) 0.067 0.058 0.039 0.085 Out-of-state populations Out-of-state populations 0.029 0.067 0.086 0.102 Maine Wisconsin Minnesota New York Laboratory StrainLaboratory Strain Long Island 1.458 0.070 0.049-0.102 empty table cell Michigan populationsMichigan populationsMichigan populationsMichigan populationsMichigan populations Kent Midland Montcalm Mecosta 1 Mecosta 2 0.054 - 0.086 0.048 - 0.071 0.028 - 0.053 0.065-0.120 0.057 - 0.090 0.055 - 0.082 0.047 - 0.094 0.056 - 0.099 0.069 0.067 0.065 0.073 0.047-0.096 0.067 Out-of-state populationsOut-of-state populations Out-of-state populations 0.022 - 0.038 0.056 - 0.078 0.050-0.141 0.080-0.126 Laboratory Strain 0.514-2.527 0.029 0.077 0.082 0.122 0.022 - 0.037 0.066 - 0.090 0.055-0.132 0.097-0.151 Laboratory StrainLaboratory Strain 0.980-3.000 1.940 Table 2 LD50's (μg per beetle) for Colorado potato beetle populations treated with thiamethoxam 7 and 10 days after treatment. empty table cell 7 days after treatment LD50(μg) Kent Midland Montcalm Mecosta 1 Mecosta 2 Michigan populations Michigan populations 0.124 0.074 0.060 0.059 0.072 Out-of-state populations Out-of-state populations 0.045 0.089 0.069 0.101 Maine Wisconsin Minnesota New York Laboratory StrainLaboratory Strain er treatment 7 days aft 95% C.L. 10 days after treatment 10 days after treatment 95% C.L. LD50(μg) Michigan populationsMichigan populationsMichigan populations 0.068-1.000 0.060 - 0.093 0.050 - 0.072 0.042 - 0.085 0.060 - 0.088 0.070 0.067 0.063 0.053 0.075 0.040 - 0.222 0.054 - 0.083 0.052 - 0.076 0.038 - 0.074 0.062 - 0.093 Out-of-state populationsOut-of-state populations Out-of-state populations 0.032 - 0.056 0.073 - 0.107 0.056 - 0.086 0.068-0.140 0.045 0.078 0.061 0.110 0.028 - 0.058 0.064 - 0.093 0.049 - 0.075 0.075 - 0.150 Laboratory Strain Laboratory StrainLaboratory Strain Long Island 0.149 0.110-0.204 0.147 0.108-0.200 Figure 1. Percent of Colorado potato beetles from 9 different Michigan populations affected (dead or poisoned) by Furadan (carbofuran), Imidan (phosmet) and Thiodan (endosulfan) after being exposed to these insecticides in petri dish resistance test kits. Nine Michigan populations from 6 counties (Delta, Houghton, Kent, Midland, Mecosta, and Montcalm), were tested for resistance to insecticides that, because of extensive use, most Michigan populations were resistant to before 1995. Petri dish resistant test kits were used (Bishop and Grafius 1991) and included separate tests for resistance to Furadan (carbofuran), Imidan (phosmet), and Thiodan (endosulfan), among others. Resistance is indicated by less than 70% of beetles affected by the insecticide. Resistance to Furadan (carbofuran) and Imidan (phosmet) was still present in most populations tested (Figure 1), although, compared with results from 1990-1994, the proportion of resistant individuals may have declined slightly. Resistance to Thiodan (endosulfan) declined during the years between 1995 and 1999, and many of the tested populations may be adequately controlled by this insecticide. However, previous experience has shown that control would likely be lost within one or two growing seasons after its reintroduction. The Houghton population was collected from an organic farm and has not been exposed to synethetic insecticides directly. As expected this population was not resistant to Furadan (carbofuran) or Thiodan (endosulfan). However, a low level of resistance to Imidan (phosmet) was present. This may have resulted from the historical use of organophosphates to control mosquitoes and blackflies in the Upper Peninsula. In the second study, field populations of Colorado potato beetles in areas of heavy imidacloprid use were monitored for resistance by calculating the time required for half of the beetles to be affected by a given dose of imidacloprid (knock down time 50 [KD 50]). Five field populations of Colorado Potato Beetle were collected in Long Island, NY in August, 1999 an additional population (Suffolk) was collected in July, 1997 (Zhao et al. 1998) and maintained without selection in the laboratory. Two other populations were collected from Hudson, NY and Midland, MI. The susceptible colony (S69), was collected in Michigan potato fields and has been reared in the laboratory at MSU for 10 years without exposure to insecticides. Topical bioassays were used to assay adult resistance. Technical-grade imidacloprid was diluted with acetone. A dose of 3.16 μg of a.i./beetle was used. For each concentration, 10 beetles were treated with 1 μl of solution on the ventral area of the abdomen. After treatment, beetles were placed in petri dishes and were fed potato leaves. Control beetles were treated with acetone alone. Three replications were performed. Knockdown of beetles was assessed periodically for 24 hours after treatment, and at 24 hours, and 3, 5, 7, and 10 days after treatment. Beetles that were unable to stand on their legs and walk a body length were considered knocked down. Beetles that did not move and showed a progressive darkening were considered dead. Table 3. The knockdown response of several strains of Colorado potato beetle to imidacloprid and imidacloprid plus piperonyl butoxide (PBO) Imidacloprid Imidacloprid Imidaclopridplus PBO Imidaclopridplus PBO Imidaclopridplus PBO population a KD50 slope ± SE Imidacloprid b RR a KD50 slope ± SE b RR Midland, MI 32 (28, 36) 3.0 ±0.3 0.46 27 (25, 30) 5.0 ±0.5 0.96 Susceptible 68 (63, 75) 4.0 ±0.3 Hudson, NY 77 (69, 85) 3.3 ±0.3 Suffolk, LI 106 (96, 116) 3.9 ±0.3 Jamesport, LI 135 (117, 157) 2.1 ±0.1 Calverton, LI 142 (125, 160) 3.1 ±0.2 Zilverton, LI 266 (216, 322) 2.8 ±0.3 Rutkoski, LI 318(293, 344) 3.4 ±0.2 1 1.1 1.5 2 2.1 3.9 4.6 Wells, LI 515 (466, 574) 3.2 ±0.4 7.5 RR= Ratio of resistance. KD50 of field population / KD50 susceptible population. a KD50 = Knock down fifty (minutes) 28(26,31) 4.5 ±0.5 58 (54, 61) 7.1 ±0.6 91 (84, 98) 6.8 ±0.9 132 (120,146) 4.1 ±0.3 89 (81, 99) 3.9 ±0.3 172(152,193) 2.8 ±0.2 2.7 ±0.3 164(141,185) 325 (281, 337) 2.7 ±0.3 1 2 3.2 4.6 3.1 6 5.7 11.3 Figure 2. Knockdown (KD50) of several strains of CPB by imidacloprid and imidacloprid + PBO. Data were analyzed by probit analysis (SAS Institute, 1988). Knock down (KD50), fiducial limits, and slopes were determined. The resistance ratios were calculated as KD50 value of the resistance colony (Long Island) divided by the KD50 value of the susceptible colony (S69). To analyze the data for knock down beetles 10 days after treatment, an arcsine transformation was used with a factorial experimental design (populations (nine) and insecticide(alone or mixed) as factors). We used the PROC GLM procedure of SAS. Knock down time ratios of Long Island populations ranged from 1.5 to 7.5 (Table 3) and Figure 2). The highest levels of Colorado potato beetle resistance were found at Wells, Rutkoski and Zilverton locations where these populations experienced eight or more imidacloprid treatments since 1995 (Admire and / or Provado). The Hudson, NY and Midland, MI population exhibited lower levels of resistance than the Long Island populations. Growers with the most resistant populations used Provado as a foliar application the first year or two (1995,1996) without using Admire in-furrow compared with growers at the Janesport site, which has the least resistant beetles, who used Admire in-furrow all four years,. The amount of active ingredient present in potato plants is higher and lasts longer for the Admire in-furrow treatments than for Provado treatments. Maybe this condition prevents the survival of some heterozygous resistant beetles. In contrast, Provado treatment has good efficacy initially. However, decay of imidacloprid residues is faster for Provado-treated plants, allowing the survival of heterozygous beetles. In addition, foliar treatments of Provado do not cover 100 % of the plant. The levels of resistance as determined by knockdown ratios in this study are lower in comparison with bioassays evaluated 7 to 10 days after treatment (results of previous bioassays evaluated in this manner indicated up to 150-fold levels of resistance). However, determination of knockdown ratios is a quicker way of diagnosing resistance. Speed of development of resistance to imidacloprid in the Colorado potato beetle Our major objective was to determine how rapidly resistance to imidacloprid increased with selection by the insecticide. We selected two different populations, a Michigan population with low-levels of resistance, and a highly resistant population from Long Island NY. Each generation individuals were treated with a dose of imidacloprid that produced 50 to 75% mortality and survivors were used to start the next generation. The resistant strain (Evans) adults and large larvae were originally collected in Montcalm County, Michigan from July to September, 1997. Two generations were reared in the laboratory without exposure to insecticide. Bioassays were conducted in March, 1998 on adults two generations removed from the original field population. Bioassays were conducted as described above in the section “Survey of resistance in field populations of Colorado potato beetle.” Susceptibility to imidacloprid was about 4.6-fold compared with a susceptible strain. The survivors of the 0.2 μg dose (15 of 41) were used to continue the strain. Adults (now 3 generations removed from the field) emerging from the culture were treated at a dose of 0.2 μg/adult. Survivors (51 adults) designated as S1 generation reproduced, and offspring were cultured to 2nd instars and used to start selection for resistance to imidacloprid. Each generation, second instars were treated topically with imidacloprid. The dose increased from 0.22 μg/larva to 0.66 μg/larva during successive selections to maintain 60-80% mortality. About 1000 2nd instars were used in each selection and survivors were cultured to the next generation. To assess the increase in level of resistance to imidacloprid, bioassays were conducted before selection and after each 2-3 selections using adults and the topical application method described above. Intoxication was evaluated at one, three, five, seven, and ten days after treatment. Beetles were supplied with fresh potato leaves during the bioassays. Beetles were recorded as walking, poisoned, or dead by the criteria described in the above section “Survey of resistance in field populations of Colorado potato beetle.” Data were analyzed by probit analysis. Lack of overlap between LD50 95% fiducial limits indicated significant differences (P<0.05). To maintain between 50% and 75% mortality during selections, the concentration of imidacloprid was increased from 0.22 μg per larva to 0.66 μg per larva. Resistance to imidacloprid developed slowly between generations. The resistance ratio based on LD50 values at seven days after treatment increased by 1.7-fold by the S6 generation of adults. The slope changed from 2.83 (generation S0) to 1.80 ( generation S6), indicating an increase of heterogeneity (Table 4). Table 4. LD50 (μg/beetle), slope and resistance ratio (LD50 Sn/LD50 S0) of Colorado potato beetles. “Evans” strain, after 3 and 6 generations of selection. generation slope (st. error) LD50 (95% f. 1.) 3 days after treatment S0 3.04(0.51) 0.064 (0.043-0.095) 3 days after treatment S3 S6 3 days after treatment 3.02 (0.55) 2.02 (0.35) 0.099 (0.064-0.15) 0.14(0.087-0.21) 7 days after treatment S0 2.83 (0.49) 0.11 (0.070-0.16) 7 days after treatment S3 S6 7 days after treatment 2.97 (0.53) 1.80(0.33) 0.11 (0.075-0.17) 0.19 (0.12-0.31) 10 days after treatment S0 2.60 (0.45) 0.12(0.074-0.18) 2.68 (0.49) 10 days after treatment S3 1.92 (0.34) S6 10 days after treatment 0.13 (0.082-0.2) 0.21 (0.14-0.32) 2- 0.68 17.38 6.15 1.37 5.65 4.69 1.86 2.81 3.46 R ratio empty table cell 1.5 2.2 empty table cell 1 1.7 empty table cell 1.1 1.8 Starting with the S6 generation, selections were done on adults using 1.0μg imidacloprid per beetle (for the S6 generation) and 1.5 μg imidacloprid per beetle (for the S7 generation). Survivors were used to start the next generation. At present, the Evans strain is 11 generations removed from the field. Eight generations have been selected with imidacloprid, either at the adult or 2nd instar stage. We are continuing selection and bioassays to determine how continued selection affects the speed of resistance development. To determine how selection with imidacloprid would affect a population that already showed a high level of resistance, we began a potato beetle population in June 1998 (NY-sel) using individuals from a laboratory strain originally collected from a potato field on Long Island, NY in 1997. The LD50 of the original strain was 2.422 (1.581—>3.710) μg/beetle, 100-fold more resistant than our most susceptible potato beetle strain. Individuals were selected with imidacloprid as adults each generation using the topical application method described above. A dose of imidacloprid was chosen that produced 50 to 75% mortality. Survivors of the selection were used to start the next generation. At this point we have selected five generations of NY-selected strain. The dose of imidacloprid needed to produce 50 to 75% mortality increased from 5.0 μg/beetle to 10.0 μg/beetle. Inheritance of resistance to imidacloprid in the Colorado potato beetle In 1998 we found that resistance to imidacloprid found in the highly-resistant Long Island strain was inherited autosomally and in an incompletely recessive manner. In 1999 we investigated the inheritance of imidacloprid resistance in Evans strain. The susceptible strain (UP) beetles were collected at the Hughes' Organic Farm in Houghton Co. in the upper peninsula of Michigan in July 1995 by Walter Pett. NY-sel resistant strain (NY-sel) beetles were collected at Sidor's farm, Mattituck, Long Island, NY on July 30, 1997 by Dale D. Moyer, Cornell Cooperative Extension, Riverhead, NY. After they were received, beetles were selected using a dose of 5.0 μg/adult using imidacloprid several times. All strains were reared at 25 ± 1°C and 16/8 hour light dark cycle on potato plants grown in greenhouse without exposure to any insecticide. The Evans strain was topically treated with imidacloprid at 0.22 μg per 2nd instar larva for two generations to obtain high homogeneity. The UP and Evans strains were reciprocally crossed (RS and SR) as "single pair" matings to produce F1 offspring. Newly emerged virgin males and females of each strain were separated until mating. One male and one female were paired in a plastic cup and fed with fresh potato leaves. There were 20 pairs for each of the reciprocal crosses. Progeny from each of the reciprocal crosses were tested. 20 pairs of backcrosses between F1 (SR) males and UP females were mated to determine whether resistance is inherited as a monogenic or polygenic trait. Chi-square values from observed and expected responses of the F1 backcrossed progeny were calculated to test the hypothesis that the resistance was monofactorially inherited (Preisler et al. 1990). No significant differences in the LD50 values were observed between the progeny of two reciprocal crosses. The degree of dominance of resistance was -0.29 and -1.27 in the progeny of the two reciprocal crosses and -0.57 based on pooled results (Table 5). This indicated that resistance to imidacloprid was inherited as incompletely recessive without sex linkage. The x2 analyses of response ratio statistics from backcrosses for a monogenic model showed insignificant deviation between observed and expected responses, indicating that one loci may be responsible for resistance to imidacloprid in the Evans-R strain. In 1998, our research indicated that more than one loci is involved in the inheritance of imidacloprid resistance in the Long Island strain. This difference may explain why the Evans strain shows very low levels of resistance while the Long Island strain is already 100-fold resistant to imidacloprid. Table 5. LD50 (μg/beetle), slope, resistance ratio and dominance of susceptible (UP) Colorado potato beetles and beetles with low levels of resistance (Evans) and 2- R ratio dominance empty table cell empty table cellempty table cell 17.3 4.27 2.08 4.75 7.86 5.65 9.21 1.52 5.05 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1.6 1.2 0.9 1.1 empty table cell -0.29 -1.27 -0.57 _____ offspring of reciprocal crosses. strain slope (st. error) LD50 (95% f. 1.) empty table cell 3 days after treatment UP Evans 3 days after treatment 3 days after treatment 1 F1 3.02(0.55) 2.39 (0.38) empty table cell 0.099 (0.064-0.15) 0.091 (0.061-0.13) 3 days after treatment 2 F1 1.91 (0.37) 0.069 (0.04-0.12) 2.23 (0.25) 3 days after treatment pooled 7 days after treatment UP Evans 7 days after treatment 7 days after treatment1F1 1.96(0.31) 2.97 (0.53) 2.08 (0.36) 0.083 (0.066-0.1) 0.071 (0.045-0.22) 0.11 (0.075-0.17) 0.083 (0.054-0.13) 7 days after treatment2F1 1.73 (0.36) 0.067 (0.037-0.12) 1.97 (0.24) 7 days after treatment pooled 1 Evans female x UP male 2 Evans male x UP female 0.078 (0.06-0.1) The NY-sel and Evans strains were reciprocally crossed as "single pair" matings to produce the F1 generation. The degree of dominance of imidacloprid resistance in the progeny of crosses between the Evans and NY-Sel strains was -0.34, -0.21, and -0.29 at three, seven, and ten days after treatment (Table 6). This suggests that imidacloprid resistance is inherited as incompletely recessive. The slope value of 0.9 indicates a high degree of heterogeneity in the progeny. Mechanisms of resistance to imidacloprid in the Colorado potato beetle and the effect of synergists Piperonyl butoxide (PBO) is a synergist that increases toxicity of insecticides in resistant Colorado potato beetles by blocking detoxification enzymes (MFO’s). Thus, an increase in toxicity of an insecticide after the addition of PBO means that those particular potato beetles use these enzymes as a mechanism of resistance. In 1998 we found that the addition of PBO reduced the resistance to imidacloprid in highly resistant (LI) beetles, although it did not make the beeties completely susceptible. In 1999, two studies were conducted evaluating the effect of piperonyl butoxide (PBO) on resistance to imidacloprid in Colorado potato beetle populations. Five Long Island, NY populations, one upstate New York population and one Midland, Michigan population were collected and bioassayed for resistance for imidacloprid, as described above ( “survey of resistance in field populations of Colorado potato beetle” ). The same populations were also exposed to PBO before imidacloprid was applied. Previous experiments showed that 5 μg/beetle of PBO did not cause mortality or adverse effects on the feeding behavior of the susceptible and resistant populations. PBO was applied an hour before the insecticide treatment. Table 6. LD50 (μg/beetle), slope, resistance ratio and dominance of highly-resistant (NY- sel) Colorado potato beetles and beetles with low levels of resistance (Evans) and offspring of reciprocal crosses. strain slope (st. error) LD50 (95% f.l.) 2- R ratio dominance 7 days after treatment UP Evans 7 days after treatment NY- 7 days after treatment sel 7 days after treatment1 F1 1.96(0.31) 1.80 (0.33) 1.85 (0.36) 0.90 (0.36) 10 days after treatment 1.52(0.29) UP 1.92(0.34) 10 days after treatment Evans 1.79(0.35) NY- 10 days after treatment sel 10 days after treatment 1 F1 0.90 (0.36) 0.071 (0.045-0.22) 0.19(0.12-0.31) 2.19(1.36-3.52) 0.5 (0.045-5.51) 0.083 (0.052-0.28) 0.21 (0.14-0.32) 2.44 (1.52-3.9) 0.5 (0.045-5.51) 7.86 4.69 2.16 0.07 4.72 3.46 0.97 0.07 empty table cell empty table cell empty table cell -0.21 empty table cell empty table cell empty table cell -0.29 1 2.7 30.8 7 1 2.5 29.4 6 PBO reduced the time for knock down in response to imidacloprid in most of the populations except for the Janesport, Suffolk and Midland populations (Table 3, Figure 2). Despite the reduction in the knock down time in the most resistant Long Island populations, PBO only partially suppressed resistance. Treatments using imidacloprid mixed with PBO suppressed the resistance in most of the populations indicating that P450 complex is a factor in the resistance to imidacloprid. However, in the Wells and Zilverton populations there was only a partial suppression of the resistance suggesting that other mechanisms of resistance may play an important role. The PBO dose may not have been high enough to totally inhibit detoxification enzymes, but, higher doses can cause mortality and reduce feeding behavior. We are conducting further research to learn more about mechanisms of resistance to imidacloprid in the Colorado potato beetle. The second study tested the effect of PBO on imidacloprid resistance in the Evans populations (low resistance, Michigan population). PBO was topically applied one hour prior to an imodacloprid bioassay using adults of the Evans strain. The dose of PBO was 1 μg per adult. To obtain high homogeneity, three generations of second instars were topically treated with imidacloprid at 2.2 ng per larva (1st and 2nd generations) and 4.4 ng per larva (3rd generation). Offspring were used for the synergism tests. Five serial doses of imidacloprid plus PBO, plus a PBO control, were used and the tests were replicated at least three times. Exposure to PBO decreased the resistance ratios of Evans potato beetles treated imidacloprid from 1.6 to 0.9, 7 days after treatment (Table 7). PBO significantly synergized imidacloprid 10 days after treatment in the Evans strain. These results indicate that mixed-function oxidase activity (which is inhibited by PBO) may be the major mechanism by which resistance develops. Table 7. LD50 (μg/beetle), slope, resistance ratio and synergist ratio of imidacloprid susceptible (UP) Colorado potato beetles and beetles with low levels of resistance to imidacloprid (Evans) with and without exposure to piperonyl butoxide (PBO). strain with PBO slope (st. error) LD50 (95% f.l.) 2 - S ratio R ratio no no yes 3 days after treatment UP 3 days after treatment Evans Evans 3 days after treatment 7 days after treatment UP Evans 7 days after treatment Evans 7 days after treatment no no yes 3.02 (0.35) 0.099 (0.064-0.15) n/a n/a 2.70 (0.57) 0.043 (0.027-0.067) 1.96(0.31) 2.97 (0.53) 2.33 (0.49) 0.071 (0.045-0.22) 0.11 (0.075-0.17) 0.062(0.037-0.1) 17.38 n/a 1.31 7.86 5.65 2.15 empty table cell empty table cell empty table cell empty table cell empty table cell 2.3 empty table cell 1 empty table cell1.6 0.9 1.8 Biological control of Colorado potato beetle Interaction between imidacloprid poisoning in Colorado potato beetle and predation by ground beetles. In 1998, we began a project to determine the effects of imidacloprid-poisoning in Colorado potato beetles on predation by ground beetles. Colorado potato beetles exposed to imidacloprid in the laboratory are often initially knocked off the plant and show signs of poisoning for several days, before recovering. We tested whether, in the field, these poisoned beetles would be vulnerable to predation, and, if so, would ingestion of poisoned potato beetles affect predatory ground beetles. Colorado potato beetles from a laboratory strain with low levels of imidacloprid resistance were treated in the laboratory with 0.2 μg of imidacloprid. After 2 hours, potato beetles showing symptoms of poisoning were placed in the bottom of a 100 x 15 mm plastic petri dish lined with filter paper (4-5 beetles per dish). Half of the dishes were left uncovered, and the other half were placed inside a nylon “knee-high” stocking, that was stretched over the petri dish and tied with a knot. One pair of petri dishes (covered and uncovered) was placed in each of 10 different locations in a potato field at the MSU Muck Research Farm, Bath MI. Dishes were checked 1 day, 2 days and 3 days later. The beetles left in each dish were counted and classified as “walking”, “poisoned” or “dead” (see section above for classification criteria). Dead beetles were removed . This test was repeated weekly for a total of four weeks (27 July, 4 Aug, 9 Aug, and 16 Aug 1999). Data are still being analyzed. During the first week (July 27), none of the poisoned beetles recovered over the three days of the test. Six beetles (13%) were missing from uncovered dishes the first day. Five beetles (11%) were missing the second day and eight beetles (17.7%) were missing the third day. In 1998 this study was conducted at the same location and up to 30% of beetles from uncovered dishes were missing by the first day. These beetles may have been consumed by predators, and evidence of predation (partially-eaten beetles and parts) was observed. Implications of imidacloprid on predatory ground beetles (Carabidae) In 1998 we had few beetles to work with. Ground beetles that fed on poisoned Colorado potato beetles did show symptoms of imidacloprid poisoning (extended legs, shaky legs and antennae, and uncoordinated movement). To collect ground beetles to replicate this study in 1999, pitfall traps were placed in tall grass adjacent to vegetable research plots at the MSU Muck Research Farm, Bath MI, on 19 Aug 1999. Traps were checked regularly from 21 Aug to 20 Sep, and any captured Pterostichus melanarus ground beetles were transported to the lab. Each beetle was placed in a large petri dish with moist filter paper and cotton ball and an untreated Colorado potato beetle. All ground beetles were starved for two days prior to testing. Two tests were conducted, one on 9 Sep and one on 20 Sep. Ten ground beetles were used in the first test and eight in the second. Ground beetles were randomly given either an untreated Colorado potato beetle or a Colorado potato beetle that had been poisoned by a topical application of 0.2 μg imidacloprid. Colorado potato beetles were treated two hours before being given to the ground beetles; this allowed us to use visibly poisoned beetles. Petri dishes were inspected at 4, 24, 48, and 72 hours, and any poisoning or mortality of either Colorado potato beetle or ground beetles was recorded, as was evidence of predation. The two tests provided very different results. Six ground beetles (3 with untreated beetles, 3 with poisoned beetles) in the first trial fed on the Colorado potato beetle, but none showed signs of poisoning and all survived the trial. One ground beetle (paired with an imidacloprid-treated Colorado potato beetle) showed signs of poisoning, yet no indications of predation were detected. In the second trial, most ground beetles attacked their Colorado potato beetle, but only one ground beetle consumed its Colorado potato beetle. This predation took place between days 3 and 4, and the ground beetie showed signs of poisoning at 72 hours. Four beetles died, two of which showed clear signs of poisoning. Biological control by entomopathogenic nematodes and Beauveria bassiana Soil samples were taken from four different locations in Michigan, washed and nematodes were extracted. Currently, no entomopathogenic nematodes have been found. To test if foliar application of nematodes would be effective in the field, a solution of approximately 500 nematodes per ml of water was applied to potato leaves at room temperature (~24° C). Complete evaporation occurred in less than 15 minutes at which time all nematodes were dead. This indicates that foliar application may not be effective in the field. Soil application may be more appropriate. Preliminary findings show that the best time to infect Colorado potato beetle is during the last (4th) instar, since they burrow into the soil to pupate, and soil applications of nematodes could target this stage. To test the pathogenicity of the entomopathogenic nematode Heterorhabditis marelatus, (Liu and Berry), a piece of filter paper was placed into a petri dish and inoculated with a 1 ml solution containing -200 nematodes. Ten 4th instar Colorado potato beetle were then added. By two days, 100% of the treated instars were dead. None of the control insects were dead (treated with pure water). Further investigations will determine the most effective concentration of nematodes to use and the environmental conditions conducive to infection. Initial tests to determine the efficacy of Beauveria bassiana as a biological control agent for Colorado potato beetie were conducted. Three concentrations of BotaniGard ES (Mycotech Corp.), within the recommended field rates were sprayed onto filter paper contained in petri dishes and 2nd instar Colorado potato beetle were added. After a few days fungal infection was observed in treated larvae. Studies are continuing to determine the most effective concentrations and environmental conditions conducive to infection. Insecticide Tests Colorado potato beetle control, 1999 Sixteen insecticide treatments (Table 8) were tested at the MSU Montcalm Research Farm, Entrican, MI for control of Colorado potato beetle. ‘ Snowden’ potatoes were planted 12 inches apart with a 34-inch row spacing on 11 May. Treatments were replicated four times in a RCB design. Plots were 50 ft long and three rows wide. Five treatments were applied at planting. Admire was applied to seed pieces as an in-furrow spray using a single nozzle hand held boom (30 gpa, 35psi). Both Maxim + CGA 293343 treatments were pre-mixed dusts applied to seed pieces (in a plastic tub) before they were planted. Another treatment consisted of a dust application of Maxim followed by an in-furrow spray of Platinum. Lastly, a dust application of Maxim was followed by sprinkling a granular fertilizer impregnated with Platinum over the seed pieces in furrow. Foliar treatments were first applied at 80% Colorado potato beetle hatch on 15 Jun. Subsequent first-generation sprays were applied on 22 Jun, 30 Jun, and 6 Jul. Avaunt (all rates) and Kryocide/Spintor (Kryocide on first and third, Spintor on second and fourth applications) were applied on each of the spray dates. Agenda (high rate) was applied on 15 Jun only, and Agenda (low rate) and Actara were applied on 15 Jun and 30 Jun. Spintor (all rates) was applied on 15 Jun and 22 Jun. Post-spray counts were made two days after each application and consisted of complete counts of Colorado potato beetle adults and larvae (small and large) on five plants from the middle row of each plot. Defoliation ratings were taken on 29 Jun and 13 Jul. Maintenance sprays of Agrimek (16 Jul and 29 Jul) and Baythroid (22 Jul) were applied to all treatments to control second generation Colorado potato beetle. 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 and significance was found at the 0.05 level with Fisher’s Protected LSD. There were significant differences in the seasonal means of egg masses, small larvae, and large larvae among treatments and check plots (Table 8). All treatments resulted in significantly fewer large larvae than the check on 24 June, 2 Jul, and 8 Jul. However, no significant differences were found between treatments on these dates, an effect most likely due to low Colorado potato beetle pressure. While most treatments provided good control of large larvae, the five treatments applied at planting provided the most consistent control. There was no significant effect between treatments on overall Seasonal mean of 1st-generation CPB/plant Seasonal mean of 1st-generation CPB/plant Egg Masses 0.162 bcd 0.050abc 0.150abcd 0.225 cd 0.238 d Seasonal mean of1st-generation CPB/plant Small Larvae 0.525abcd 0.006a 0.444abc 0.256ab 1.494 d Seasonal mean of 1st-generation CPB/plant Large Larvae 0.038a 0.100a 0.000a 0.000a 0.325ab Adults 0.000a 0.025abc 0.000a 0.000a 0.000a 0.287 d 1.494 d 0.325ab 0.013ab 0.275 d 0.775 bcd 0.250ab 0.000a 0.225 d 0.775 bcd 0.025ab 0.000a 0.038ab 0.006a 0.013a 0.006a 0.062a 0.025a 0.050abc 0.088 bc 0.250ab 0.100 cd 0.100a 0.000a 0.075abc 0.075abc Table 8. Seasonal mean number of Colorado potato beeltes per plant. Treatment/formulation Actara 25WG Admire 2Fa Agenda 1.67SC Agenda 1.67SC Avaunt 30WG + PBO-8 + Dyne-amic Avaunt 30WG + PBO-8 + Dyne-amic Avaunt 30WG + PBO-8+ Dyne-amic Kryocide 96 + Spintor 2SC Maxim 0.5 DSb + Platinum 2SCa Maxim 0.5 DSb + Platinum 2SC (1999 Impregnation)c Maxim 0.5 DS + CGA 293343 (1:2 prepack)b Rate 14.2 g (AI)/acre 13.0 fl oz (Form)/acre 0.038 lb (AI)/acre 0.05 lb (AI)/acre 0.045 lb (AI)/acre 0.25 lb (AI)/acre 0.15 gal (Form)/acre 0.065 lb (AI)/acre 0.25 lb (AI)/acre 0.15 gal (Form)/acre 0.11 lb (AI)/acre 0.25 lb (AI)/acre 0.15 gal (Form)/acre 9.6 lb (AI)/acre 4.5 fl oz (Form)/acre 8.0 oz (Form)/cwt 6.5 fl oz (Form)/acre 8.0 oz (Form)/cwt 250 lb (Form)/acre 8.0 oz (Form)/cwt Maxim 0.5 DS + CGA 293343 (1:2.4 prepack)b 8.0 oz (Form)/cwt 0.050abc 0.000a 3.0 fl oz (Form)/acre 4.5 fl oz (Form)/acre 6.0 fl oz (Form)/acre Spintor 2SC Spintor 2SC Spintor 2SC Untreated check 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. a treatment applied in-furrow at planting b treatment applied to seed pieces as dust before planting c fertilizer sprinkled over seed pieces in-furrow at planting 0.150abcd 0.262 d 0.288 d 0.213 cd 0.325abc 1.438 cd 0.737 bcd 0.962 bcd 0.525 b 0.563 b 0.337ab 4.200 c 0.000a 0.038abc 0.062abc 0.175 d empty table cell Table 9. Mean potato yield (pounds per row) harvested and mean defoliation rating d on two dates. CPB trial Defoliation rating d Defoliation rating d Size A Yield (lb/plot) 97.50 103.65 91.55 99.40 81.90 Yield (lb/plot) Size B 4.40abc 6.20 cde 5.95 bcde 5.00abcde 4.05ab Yield (lb/plot) Total 101.90 109.85 97.50 104.40 89.95 29 Jun 1.00 bc 0.00abc 1.00 bc 1.00 bc 1.00 bc 13 Jul 0.50abc 0.75 bcd 0.50abc 0.00a 1.00 cd 102.85 5.10abcde 107.95 1.50 c 1.00 cd 96.05 4.65abcd 100.70 1.00 bc 1.00 cd 98.90 5.75 bcde 104.65 0.75abc 0.50abc 88.50 5.70 bcde 94.23 83.75 3.20a 86.95 0.00a 0.00a 0.25ab 0.75 bcd Rate 14.2 g (AI)/acre 13.0 fl oz (Form)/acre 0.038 lb (AI)/acre 0.05 lb (AI)/acre 0.045 lb (AI)/acre 0.25 lb (AI)/acre 0.15 gal (Form)/acre 0.065 lb (AI)/acre 0.25 lb (AI)/acre 0.15 gal (Form)/acre 0.11 lb (AI)/acre 0.25 lb (AI)/acre 0.15 gal (Form)/acre 9.6 lb (AI)/acre 4.5 fl oz (Form)/acre 8.0 oz (Form)/cwt 6.5 fl oz (Form)/acre 8.0 oz (Form)/cwt 250 lb (Form)/acre Treatment/formulation Actara 25WG Admire 2Fa Agenda 1.67SC Agenda 1.67SC Avaunt 30WG + Avaunt 30WG + PBO-8 + Dyne-amic PBO-8 + Dyne-amic Avaunt 30WG + PBO-8+ Dyne-amic Kryocide 96 + Spintor 2SC Maxim 0.5 DSb + Platinum 2SCa Maxim 0.5 DSb + Platinum 2SC (1999 Impregnation)c Maxim 0.5 DS + CGA 293343 (1:2 prepack)b Maxim 0.5 DS + CGA 293343 (1:2.4 8.0 oz (Form)/cwt 8.0 oz (Form)/cwt 82.55 6.35 de 88.90 0.25ab 0.75ab 8.0 oz (Form)/cwt 8.0 oz (Form)/cwt 91.70 4.60abcd 96.30 0.25ab 0.25ab 3.0 fl oz (Form)/acre 4.5 fl oz (Form)/acre 6.0 fl oz (Form)/acre prepack)b Spintor 2SC Spintor 2SC Spintor 2SC Untreated check Means within a column followed by different letters are significantly different (P<0.05, Fisher’s Protected LSD). a treatment applied in-furrow at planting b treatment applied to seed pieces as dust before planting c fertilizer sprinkled over seed pieces in-furrow at planting d Defoliation rating: 0, no defoliation; 1, slight damage to leaflets; 2, at least 50% defoliation of some compound leaves; 6.10 cde 6.60 e 6.60 e 4.65abcd 1.00 bc 0.75abc 1.00 bc 3.00 d 106.80 104.20 97.20 93.95 100.70 97.60 90.60 89.30 1.25 d 1.00 cd 1.00 cd 2.25 e empty table cell yield (Table 9). The highest yields were harvested from plots treated with Admire, Avaunt (0.065 lb. AI/acre), and Spintor (3 fl oz/acre), respectively. Compared with the check, defoliation ratings were significantly lower for all treatments. Potato leafhopper control, 1999: Seven insecticide treatments (Table 10) were tested at the MSU Montcalm Research Farm, Entrican, MI for control of potato leafhopper (PLH). ‘Atlantic’ Bt by NatureMark® seed potatoes were planted 12 inches apart with a 34-inch row spacing on 20 May. Plots were 50 ft single rows arranged in a RCB design with four replications per treatment. Five treatments were applied at planting. Admire was applied to seed pieces as an in-furrow spray using a single nozzle hand held boom (30 gpa, 35 psi). Both Maxim + CGA 293343 treatments were pre-mixed dusts applied to the seed pieces before they were planted. Another treatment consisted of a dust application of Maxim followed by an in-furrow spray of Platinum. Lastly, a dust application of Maxim was followed by sprinkling a granular fertilizer, impregnated with Platinum, over the seed pieces in the furrow. The foliar treatment, Actara, was applied when potato leafhopper numbers exceeded 1.0 adults/sweep or 0.5 adults/sweep and nymphs were present Actara was sprayed on 30 Jun, 13 Jul, 20 Jul, 26 Jul, and 3 Aug. Post-spray counts were conducted two days after each application. Both a sweep net sample (ten sweeps per plot) and a visual count of potato leafhopper adults and nymphs on six leaves (two near top, two from middle, and two near base of plant) from five randomly selected plants were performed on each plot. On 1 Sep, each plot was harvested mechanically and the tubers were separated by size and weighed. Data were analyzed using two-way ANOVA and significance was found at the 0.05 level with Fisher’s Protected LSD. There were no significant differences in the seasonal means of potato leafhopper adults and nymphs among treatments and check plots for either sampling technique (Table 10). Also, there was no significant effect between treatments on overall yield (Table 11). The highest yields were harvested from plots treated with Maxim + Platinum (1999 Impregnation), Maxim + CGA 293343 (1:2 prepack), and Maxim + Platinum. Literature Cited: Bishop, B.A. and E.J. Grafius. 1991. An on-farm insecticide resistance test kit for Colorado potato beetle (Coleoptera: Chrysomelidae). American Potato Journal 68: 53-64. Bishop, B.A. and E.J. Grafius. 1996. Insecticide resistance in the Colorado potato beetle. p 355-377 In: Chyrsomelidae Biology, Vol I: The Classification, Phylogeny and Genetics. P.H.A. Jolivet and M.L. Cox (eds.). SPB Academic Publishing, Amsterdam, the Netherlands. Grafius, E. J. 1997. Economic impact of insecticide resistance in the Colorado potato beetle (Coleoptera: Chrysomelidae) on the Michigan potato industry. J. Econ. Entomol. 90(5): 1138-1143. MacNeil, C.R.. 2000. Resistance to Admire/Provado detected on Long Island. Vegetable Grower’s News 34(1): 22. SAS Institute. 1988. SAS / Stat user’s guide, version 6 ed. SAS Institute, Cary, NC. Zhao, J., B. A. Bishop, and E. J. Grafius. 1998. Inheritance and synergism of resistance to imidacloprid in the Colorado Potato Beetle (Coleoptera: Chrysomelidae) (In press) Table 10. Seasonal mean number of potato leafhopper (PLH) adults and nymps per 10 sweeps and per 6 leaves. Seasonal mean of PLH/10 sweeps Seasonal mean of PLH/10 sweeps PLH nymph PLH adult Seasonal mean of PLH/six leaves Seasonal mean of PLH/six leaves PLH nymph PLH adult 6.167 4.375 5.250 0.042 0.375 0.000 0.233 0.375 0.142 0.100 0.033 0.025 5.041 5.334 3.208 4.750 0.042 0.000 0.042 0.000 0.143 0.183 0.133 0.233 0.033 0.033 0.008 0.117 Size A Yield (lb/plot) 34.80 32.60 38.25 43.60 38.60 37.60 33.25 Yield (lb/plot) Size B 2.20 2.60 2.70 Total Yield (lb/plot) 37.00 35.20 40.95 1.85 2.75 2.05 2.40 45.45 41.35 39.65 35.65 Table 11. Mean yield of potatoes (pounds per row), potato leafhopper trial Treatment/formulation Actara 25WG Admire 2Fa Maxim 0.5 DSb + Platinum 2SCa Maxim 0.5 DSb + Platinum 2SC(1999 Impregnation)c Maxim 0.5 DS + CGA 293343 (1:2 prepack)b Maxim 0.5 DS + CGA 293343 (1:2.4 prepack)b Untreated check Rate 14.2 g (AI)/acre 13.0 fl oz (Form)/acre 8.0 oz (Form)/acre 6.5 fl oz (Form)/acre 8.0 oz (Form)/acre 250 lb (Form)/acre 8.0 oz (Form)/acre 8.0 oz (Form)/acre empty table cell Treatment/formulation Actara 25WG Admire 2Fa Maxim 0.5 DSb + Platinum 2SCa Maxim 0.5 DSb + Platinum 2SC(1999 Impregnation)c Maxim 0.5 DS + CGA 293343 (1:2 prepack)b Maxim 0.5 DS + CGA 293343 (1:2.4 prepack)b Rate 14.2 g (Al)/acre 13.0 fl oz (Form)/acre 8.0 oz (Form)/acre 6.5 fl oz (Form)/acre 8.0 oz (Form)/acre 250 lb (Form)/acre 8.0 oz (Form)/acre 8.0 oz (Form)/acre Untreated check a treatment applied in-furrow at planting b treatment applied to seed pieces as dust before planting c fertilizer sprinkled over seed pieces in-furrow at planting empty table cell Funding: GREEEN Combining Varietal Resistance with Managed Fungicide Applications for the Control of Potato Late Blight. W. W. Kirk 1, D. S. Douches 2 , R. Hammerschmidt 1, J. A. Stein 1, R.S. Schafer 1, R. Scott Shaw 1 and B.A. Niemira 1. Departments:1 Botany and Plant Pathology, 2 Crop and Soil Sciences (DSD) Contact address, 35 Plant Biology, Botany and Plant Pathology, Michigan State University, East Lansing MI48824, (517) 353-4481, Fax (517) 353-1926, e-mail kirkw@msu.edu Introduction Late blight (Phytophthora infestans) is a major threat to the production of high quality potatoes in Michigan. The appearance of a more aggressive strain of P. infestans (US8), resistance of this pathogen to metalaxyl and the potential loss of some currently effective protective fungicides, compounds the serious nature of this problem. The economics of crop production demand that cost effective crop protection is a prime concern for the whole industry. Public pressure to reduce crop production inputs without compromising crop quality is increasing. The North American late blight workshop held at Tucson, AZ in 1997 identified that the development of integrated crop protection programs that focus on durable resistance to potato late blight should be considered as a priority for the North American potato industry. Durable resistance was defined as production systems that utilized potato cultivars with reduced susceptibility to late blight in combination with managed fungicide applications. Successful, long-term control of this disease will require a combined effort that will incorporate the use of carefully managed fungicide programs, resistant varieties developed through breeding and the use of novel resistance mechanisms such as those achieved via genetic engineering. The objective of this research was aimed at developing the tools necessary to control late blight using fungicides in combination with heritable host resistance. Experiments in 1999 were set up to evaluate the efficacy of crop protection programs against potato late blight utilizing fungicides with a) reduced amounts of commercially available fungicide and with reduced amounts of novel fungicides with lower amounts of active ingredient fungicides and b) with reduced amounts of commercially available fungicide at reduced application frequency. Materials and methods Potato tubers were planted at the Michigan State University Muck Soils Experimental Station, Bath, MI on 1 June into two-row by 25-foot plots, (experiment a, reduced amounts of fungicide) and two-row by 12-foot plots (experiment b, reduced amounts of commercially available fungicide at reduced application frequency). Both experiments were planted with 9-inch between plants and at 34-inch row spacing) replicated four times in a randomized complete block design. The two-row beds were separated by a five-foot blank row. Plots were irrigated as needed with sprinklers and were hilled immediately before sprays began. All plants were inoculated (100 ml/25-foot row) with a zoospore suspension of Phytophthora infestans US8 (insensitive to metalaxyl, A2 mating type) genotype (103 zoospores/ml) on 23 Jul. Fungicides were applied from 25 Jun to 13 Aug (9 applications expt. a, 5 - 15 applications expt. b) with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Weeds were controlled by hilling and with Dual 8E (2 pt/A on 5 Jun), Basagran (2 pt/A on 15 Jun and 5 Jul) and Poast (1.5 pt/A on 23 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 26 Jun), Sevin 80S (1.25 lb on 1 and 23 Jul), Thiodan 3EC (2.33 pt/A on 1 and 21 Aug) and Pounce 3.2EC (8 oz/A on 23 Jul). Plots were rated visually for percentage foliar area affected by late blight on 23, 31 Jul, 7, 14 and 23 Aug. Late blight disease severity values were calculated using the Wallin model from temperature and relative humidity values recorded at canopy level with a remote access weather station. Experiment a) active ingredient and variety interaction trial: the fungicides chlorothalonil (Bravo WS 6SC) and fluazinam 5SC were applied at 33, 67 and 100% of the recommended field application rates. Chemical treatments were begun before inoculation with the US8-A2 biotype of P. infestans (three applications). Experiment b) application timing frequency and variety interaction trial: the fungicide chlorothalonil (Bravo WS 6SC) was applied at 33, 67 and 100% of the recommended field application rates at intervals of 5, 10 and 15 days in two varieties varying in susceptibility to late blight, MSG 274-3 (moderately resistant) and Snowden (susceptible). Chemical treatments were begun before inoculation with the US8-A2 biotype of P. infestans and varied from four applications (5 day program), 3 applications (10 day program) and 2 applications (15 day program). Foliar late blight was assessed at various times after inoculation, with 32 days after inoculation (dai) taken as a key reference point. The average amount of disease that developed over the disease progress period was expressed as the relative area under the disease progress curve (RAUDPC). The area under the disease progress curve (AUDPC) was calculated by adding the area under the linear progression of disease between each successive estimation of disease from inoculation to 32 days after inoculation. The RAUDPC is calculated by dividing the measured AUDPC by the maximum AUDPC (100 x duration of the epidemic, from inoculation to 100% plant death). The RAUDPC was expressed with a maximum value of 100. An arbitrary scale of resistance to late blight was determined related to RAUDPC: 0-5, resistant; 5 - 10, moderately resistant; 10 - 20 moderately susceptible; > 20 susceptible. Data were analyzed by three-way analysis of variance and means compared at P = 0.05 level of significance by a multiple range comparison of means (Tukey, SAS). Varietal Selection Varieties for the active ingredient and variety interaction trial were selected form the 1998 breeding program late blight assessment trial. This material consisted of commercial cultivars, putative resistant germplasm and advanced breeding lines from MSU and other university potato breeding programs. No fungicides were applied during the season. Inoculation with the US8 biotype of P. infestans was made 23 Jul when foliage was vigorous and healthy. Foliar disease was assessed frequently after 'inoculation (minimum 5 days) and RAUDPC (see above) was calculated to evaluate disease development over the season until 28 days after inoculation. The varieties that had low RAUDPC values (10 - 20) and with the best agronomic qualities were selected for inclusion in the 1999 active ingredient and variety interaction trial. The variety and the advance breeding line selected for the application timing frequency and variety interaction trial were selected as representative lines which were susceptible or moderately resistant to late blight consistently over three years of variety trials (data presented in late blight assessment reports, Michigan Potato Research Report 1996 - 1998). Results, 1999 field season: Late blight developed rapidly during August and untreated controls in susceptible varieties reached 85 - 95% foliar infection by 14 Aug. The accumulated late blight disease severity values from June 13 to Aug 30 were 78, which indicated that environmental conditions were highly conducive for the development of late blight. Experiment a) active ingredient and variety interaction trial: The varieties had significantly different responses to the inoculation of P. infestans, US8 biotype (Fig 1, 0 rate of fungicide application). All varieties tested were classified as susceptible to late blight (RAUDPC > 20) were in the untreated controls except G 274-3 which was classified as moderately resistant (RAUDPC 5 - 10). A091-1 had significantly lower RAUDPC value (ca. 22) than the most susceptible varieties Atlantic, Snowden and E246-5 (≥40). Varieties E018-1, FL1833 and FL1533 had RAUDPC values between 30 and 40 and FL1625 and A091-1 were between 20 - 30. Most fungicide programs (chlorothalonil and fluazinam, full rate) applied as protectants reduced the level of late blight foliar infection significantly (p = 0.05) compared to the untreated control of the most susceptible variety (Snowden) at the full rate of application in all varieties (Fig 1). Fungicide application rates of 0.33 of chlorothalonil and fluazinam did not affect the RAUDPC value of G274-3 however rates of 0.67 and 1.0 of both fungicides reduced the RAUDPC values to below 5 (Fig 1). The reduction in RAUDPC in G274-3 was not statistically significant (p = 0.05) between rates of fungicide from 0-1.0 of either fungicide. Fungicide application rates of 100% chlorothalonil decreased the RAUDPC to about 10 in only Atlantic, FL1833 and E246-5 (Fig 1). There was a clear reduction in RAUDPC with increase in dose application rate for most varieties however, in some varieties e.g. A091-1, there was little change in RAUDPC between 0.0 and 0.33 rates after application of either fungicide. There was some indication that some varieties responded more to chlorothalonil (e.g. FL1833) than to fluazinam (e.g. FL1533) at the lowest rate of application (Fig 1) however most varieties responded more to fluazinam than to chlorothalonil at 0.33 application rate. Generally, the reduction in RAUDPC was linear between 0 and 0.67 application rates in most varieties then a lower reduction from 0.67 to 1.0 application rate for both fungicides (Fig 1). Experiment b) application timing frequency and variety interaction trial: G274-3 and Snowden had significantly different responses to the inoculation of P. infestans, US8 biotype (Fig 2, 0 rate of fungicide application). Snowden was classified as susceptible to late blight (RAUDPC > 20) but G274-3 was classified as moderately resistant (RAUDPC 5-10). The interval and rate of application of chlorothalonil made no significant difference to the RAUDPC recorded in G274-3, which was less than 5 for all combinations (Fig 2). In Snowden, application of chlorothalonil at 0.33 -1.0 full rate of application at 5 day application intervals significantly reduced the RAUDPC (to between 5 and 10) in comparison to the untreated Snowden control (Fig 2). There were no significant differences between the application rates of chlorothalonil at the 5 day application interval. At the 10 and 15 day application intervals the RAUDPC remained > 20 at all rates and intervals except at the 10 day interval, full application rate which was close to 20 (Fig 2). Discussion Combination of varietal resistance with chemical applications can provide effective disease control. This can be accomplished at lower rates of application with a conventional fungicide e.g chlorothalonil (Bravo WS 6SC) or with the novel fungicide fluazinam with a lower amount of active ingredient. In previous years, reduced amounts of both chlorothalonil and fluazinam were effective at all application rates tested on all varieties in comparison with the untreated controls. However, in 1999 the environmental conditions were more favorable for the development of late blight and the lowest application rates proved unsatisfactory. The least susceptible varieties as in previous years e.g. G274-3 did not respond to application of rates greater than 33% of the full recommended rate of either fungicide. This suggests that for control of current biotypes of late blight in the US, a fungicide program is barely necessary except perhaps for control of other pathogens such as early blight (Alternaria solani). Trials conducted in 1997 and 1998, suggested that an application interval of 10 days only resulted in acceptable disease control in the least susceptible varieties and advanced breeding lines treated with 100% of the recommended rate of chlorothalonil. The results in 1999 confirmed this result. Application of fungicides at 10 and 15 day application intervals gave unsatisfactory control of late blight at all rates of chlorothalonil tested. The efficacy of fluazinam at an application interval of 10 or 15 days at reduced application rates was not evaluated. The similarity in efficacy against late blight between chlorothalonil and fluazinam in the 1998 trials suggests that fluazinam may not be effective at reduced application rates beyond a 7-day application interval. The activity of fluazinam at reduced rates of application and decreased frequency of application interval against late blight needs to be determined in the varieties that were least susceptible to late blight. The opportunity for reduction of fungicide applications by managing the rate of application of traditional fungicides and novel fungicides with lower amounts of active ingredient in varieties less susceptible to late blight is clear. More critical dose response studies are required for new chemicals to establish effective rates of application for the control of late blight. The efficacy of reduced rates of these fungicides against other potato pathogens such as A. solani (early blight) has not been established and may prove to be a major constraint in the adoption of managed rate fungicide applications. The MSU advanced selection, G274-3, was the advanced breeding line with the most outstanding foliar resistance in the trial. G-274-3 also has good horticultural characteristics. G274-3 will continue to be used as a parent to transfer resistance to other genetic backgrounds and be developed as a commercial line. The varieties falling into the moderately susceptible category may be protected with reduced application rates of protectant fungicides and some of these lines will be evaluated in 1999 in the managed fungicide application trial. Some of the lines that are most resistant to late blight will be used as parental material in the MSU Potato Breeding Project. This group included many unadapted varieties and breeding lines. Figure 1. Relative area under the disease progress curve (max = 100) in potato varieties and advanced breeding lines protected with reduced and full rates of chlorothalonil or fluazinam and inoculated with P. infestans (US8, A2). Cvs ranked in decreasing order of susceptibility to P. infestans (determined in this trial). Accumulated late blight Disease Severity Values = 78 from June 13 to August 30, 1999. Figure 2. Effect of dose rate and application frequency on late blight development in moderately resistant (MSG 274-3) and sensitive (Snowden) potato varieties. Black symbols = Snowden, White symbols = MSG 274-3; ■, 5 day, •, 10 day and ♦, 15 day application frequency. Accumulated late blight Disease Severity Values = 78 from June 13 to August 30, 1999. The Role of Dimethomorph within a Potato Late Blight (Phytophthora infestans) Control Program. Mixture partners and optimal application timing. Funding: Industry J.M. Stein, W.W. Kirk, R.L. Schafer and M.R. Durkin Room 35 Plant Biology Building, Department of Botany and Plant Pathology Michigan State University, East Lansing, MI 48824, USA Introduction Potato late blight (Phytophthora infestans) is the most important potato pathogen in the United States. Yield loss is direct through tuber infection and the associated rot or indirect through a reduction of photosynthetic potential. Control of late blight is achieved by cultural practices and foliar fungicide based control programs. In Michigan the standard program consists of regular preventative applications of chlorothalonil (e.g. Bravo WS) or EBDC (e.g. Penncozeb) based fungicides. The initiation of fungicide application typically occurs prior to row closure. Spray program factors may be partly based upon weather conditions. When late blight is present, or when weather conditions are conducive to disease, additional or alternative fungicides may be employed. These fungicides may also have properties (e.g. antisporulation or curative) that allow for the specific positioning of the product at certain points within the season and under certain conditions. Field trials were conducted in the presence of late blight in order to evaluate the optimal placement and rate of dimethomorph and mixture partners within a chlorothalonil based foliar fungicide control program with respect to foliar disease levels and tuber loss due to late blight. Methods Cut potato seed (cv. Snowden) was planted at the Michigan State University Muck Soils Experimental Station, Bath, MI on 6 June 1999 into two-row by 25-foot plots (34-inch row spacing) replicated four times in a randomized complete block design. The two-row beds were separated by a five-foot unplanted row. Weeds were controlled by hilling and with Dual 8E (2 pt/A on 5 Jun), Basagran (2 pt/A on 15 Jun and 5 Jul) and Poast (1.5 pt/A on 23 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 6 Jun), Sevin 80S (1.25 Ib/A on 1 and 23 Jul), Thiodan 3EC (2.33 pt/A on 1 and 21 Aug) and Pounce 3.2EC (8 oz/A on 23 Jul). Plots were irrigated as needed with sprinklers and managed under standard potato agronomic practices. Plots were inoculated (3.38 fl-oz/25-foot plot) with a mixed isolate zoospore suspension of Phytophthora infestans US8/A2 at 104 spores/fl-oz on 10 Aug. Fungicides were applied with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Application commenced on 6 July and continued on a seven day schedule for a total of eight applications. See Table 1 for fungicide programs. Vines were killed with Diquat 2EC (1 pt/A on 28 Aug and 4 Sep). The number of plants emerged per row for both rows within each plot was counted on 16 July. Plots were rated visually for percentage foliar area affected by late blight on 6, 13, 20, and 28 Aug and 8 Sept. The relative area under the disease progress curve (RAUDPC) was calculated for each treatment. On 9 Aug four plants per plot were destructively harvested and the number and size of tubers per plant was counted. Tubers were separated into two groups, those smaller than (size B), or larger than (size A), ~1.25 inch diameter. On 21 Sep plots were harvested mechanically and yields were taken for each size group. The number of tubers per plot was then counted and an area under the tuber loss curve (AUTLC) was generated for both size classes. This is a season long measure of the number of tubers per plant. Larger AUTLC values indicated that tuber survival was greater over the growing season. Excluding the untreated control and season-long mancozeb (Penncozeb) or chlorothalonil (Bravo WS) programs, each control program was based on chlorothalonil applications with a 7 day spray interval. The first replacement program consisted of two dimethomorph-based (Acrobat 50 WP) fungicide(s) applications prior to inoculation. The second program consisted of one application prior to inoculation and one prior to dessication. Rates used for dimethomorph and mancozeb are based upon those used in the label rate application of Acrobat MZ 69WP (2.251b/A). Increased rate dimethomorph applications were twice the label rate. Chlorothalonil rates followed recommendations on the product label. Results Foliar and yield results are in Table 1. The level of foliar infection for the fungicide programs was significantly lower than the untreated control for each assessment. In only the final foliar assessment did fungicide programs differ significantly from each other. The program in which mancozeb and dimethomorph were co-applied as replacements for chlorothalonil one application before inoculation and dessication had significantly lower foliar disease than the double rate dimethomorph treatment with the same application timing. The remaining programs did not differ from the previously listed programs. The RAUDPC followed the same trend as final foliar disease. The program with the highest marketable yield was the season-long mancozeb program. Six of ten fungicide programs had significantly lower marketable yield. Additional variation existed, but no patterns were noted. The total yield per plot did not differ significantly between treatments. Tuber number results are in Table 2. At the first tuber assessment point differences existed in the number of size B (< ~ 1.25 inch) tubers per plant, but not the number of marketable sized (size A) tubers per plant. A similar trend existed for the final number of tubers per plant for both size grades. For the size B tubers, the untreated control had the largest AUTLC value. The fungicide programs had significant differences. For the marketable tuber size class no significant differences existed between treatments for the AUTLC. Discussion In terms of foliar disease, all of the fungicide programs were as effective as the season long chlorothalonil program, but none were significantly better. Excluding the difference between the program in which mancozeb and dimethomorph were co-applied as replacements for chlorothalonil one application before inoculation and dessication and the double rate dimethomorph treatment with the same application timing, the programs were essentially identical in terms of late blight foliar disease levels. The programs with early or full season mancozeb use tended to have increased yield regardless of the level of foliar late blight. This effect may be due to activity against non-target pathogens such as Alternaria solani. The use of dimethomorph alone, at both label and twice label rates for each timing program, tended to have increased foliar infection levels and reduced yield. Since the amount of active applied was relatively small, this was not surprising. The number of emerged plants per experimental plot did not differ significantly, indicating statistically acceptable comparisons of tuber number and AUTLC. The lack of significant differences between the number of marketable tubers per plant and the AUTLC for each treatment suggested that programs with larger yields were undergoing more tuber bulking and producing larger tubers without increasing tuber number. The use of both chlorothalonil and mancozeb as mixture partners for dimethomorph is feasible. Economic considerations do not support the addition of dimethomorph as no apparent benefit was gained. However, recent legislative (FQPA) activities may eventually call for the reduction of the amount of chlorothalonil and mancozeb applied. The examination of reduced rate chlorothalonil or mancozeb applications with full rate dimethomorph may allow for an overall reduction in restricted fungicide usage without compromising efficacy. Additionally, certain fungicides with specific effects upon the pathogen and the optimal placement of these products within a prophylactic fungicide based program should be examined further. Table 1. Treatments, schedule and rate of active components applied. Percent foliar late blight at each assessment date, relative area under the disease progress curve (RAUDPC) values, and yield for both marketable and total tubers._____________________________________________________ Treatment Bravo WS 6SC, Bravo WS 6SC Bravo WS 6SC, Penncozeb 80DF Bravo WS 6SC, Bravo WS 6SC + Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Bravo WS 6SC + Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Penncozeb 80DF + Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Penncozeb 80DF + Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Acrobat 50WP, Bravo WS 6SC Untreated 4-8 1 2,8 3-7 1 2-3 1 2-8 1 2-8 1 2-3 Schedule1 Rate Active (Ibs/A) 0.75, 1.00 0.75, 1.35 0.75, 1.00 + 0.20, 1.00 0.75, 1.00 + 0.20, 1.00 0.75, 1.35 + 0.20, 1.00 0.75, 1.35 + 0.20, 1.00 0.75, 0.20, 1.00 0.75, 0.20, 1.00 0.75, 0.40, 1.00 0.75, 0.40, 1.00 n/a 3-7 1 2-3 4-8 1 2,8 3-7 1 2-3 4-8 1 2,8 3-7 n/a 4-8 1 2,8 Percent Foliar Blight 2 Percent Foliar Blight 2 Percent Foliar Blight 2 Percent Foliar Blight 2 RAUDPC3 Yield (cwt/A) Yield (cwt/A) 8/13/99 8/20/99 8/28/99 9/08/99 Size A4 Total 0.00 a5 0.66 a 2.66 a 68.33 ab 0.13 ab 257.2 bc 294.9 a 0.00 a 0.33 a 2.33 a 61.66 ab 0.12 ab 311.7 a 343.8 a 0.00 a 0.00 a 2.33 a 70.00 ab 0.13 ab 240.6 bcd 280.1 a 0.00 a 1.00 a 2.00 a 56.66 ab 0.11 ab 279.7 abc 310.4 a 0.00 a 0.66 a 3.66 a 56.66 ab 0.11 ab 289.6 ab 318.2 a 0.00 a 0.00 a 0.33 a 53.33 a 0.10 a 229.2 cd 260.2 a 0.00 a 0.33 a 1.66 a 68.33 ab 0.13 ab 250.1 bc 298.4 a 0.33 a 0.66 a 1.33 a 66.66 ab 0.12 ab 226.8 cd 251.4 a 0.00 a 0.00 a 1.00 a 66.66 ab 0.12 ab 260.0 abc 303.7 a 0.00 a 0.66 a 2.66 a 71.66 b 0.14 b 241.4 bcd 277.3 a 4.00 b 26.00 b 93.33 b 100.0 c 0.52 c 192.3 d 250.3 a 1. Application schedule; 6, 13, 20, 27 July, 3, 10, 17, 24 Aug. 2. The foliar assessment on 6 Aug. represents a pre-inoculation assessment and was NSD at a = 0.05 (LSD) 3. Relative Area Under the Disease Progress Curve 4. Represents tubers > ~1.25 inch diameter 5. Values followed by the same numbers are NSD at α = 0.05 (LSD) Table 2. Treatments and schedule. Number of tubers per plant at both assessment points and the area under the tuber loss curve (AUTLC) for tubers sizes.__________________________________ Treatment Schedule 1 Number of Tubers/Plant 2 Number of Tubers/Plant 2 AUTLC 3 AUTLC 3 Bravo WS 6SC, Bravo WS 6SC Bravo WS 6SC, Penncozeb 80DF Bravo WS 6SC, Bravo WS 6SC + Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Bravo WS 6SC + Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Penncozeb 80DF + Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Penncozeb 80DF + Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Acrobat 50WP, Bravo WS 6SC Bravo WS 6SC, Acrobat 50WP, Bravo WS 6SC Untreated Number of Tubers/Plant 28/09/99 8/09/99 9/21/99 Number of Tubers/Plant 29/21/99 Size B Size A B A B A 7.78 ab4 4.74 a 2.73 bc 7.10 a 63.09 abc 74.00 a 10.32 c 7.43 a 2.55 bc 9.02 a 77.29 cd 98.74 a 7.95 abc 3.97 a 3.06 abc 8.14 a 66.06 abc 65.08 a 8.67 bc 4.74 a 2.30 bc 7.15 a 65.87 abc 72.82 a 9.30 bc 5.01 a 1.90 a 6.87 a 67.26 bc 72.99 a 6.07 a 5.90 a 2.39 bc 7.39 a 50.80 a 76.32 a 7 26 ab 5.32 a 4.06 bc 7.58 a 68.00 bc 80.76 a 7.75 ab 4.40 a 2.01 a 7.59 a 58.60 ab 69.00 a 7.07 ab 4.10 a 3.41 bc 6.42 a 62.94 abc 70.17 a 7.45 ab 7.80 a 2.65 bc 7.10 a 60.70 ab 85.37 a 9.46 bc 4.69 a 5.46 d 6.81 a 89.60 d 70.78 a 1 2-8 1 2-8 1 2-3 4-8 1 2,8 3-7 1 2-3 4-8 1 2,8 3-7 1 2-3 4-8 1 2,8 3-7 1 2-3 4-8 1 2,8 3-7 n/a 1. Application schedule; 6, 13, 20, 27 July, 3, 10, 17, 24 Aug. 2. Size B: tubers <~ 1.25 inch diameter, Size A: tubers >~1.25 inch diameter 3. Area Under the Tuber Loss Curve - larger values mean more tubers. 4. Values followed by the same numbers are NSD at α = 0.05 (LSD) Funding: Industry Chemical control of potato late blight 1999 W.W. Kirk, R.L. Schafer, J.M. Stein, R. Scott Shaw and K. Baker Room 35 Plant Biology Building, Department of Botany and Plant Pathology Michigan State University, East Lansing, MI 48824, USA Introduction Potato late blight (Phytophthora infestans) is the most important potato pathogen in Michigan. For five years in succession, successful epidemics have been established at the Michigan State University Experimental Research Farm, Bath, ML In 1999, several foliar fungicide efficacy trials were carried out to establish the efficacy of fungicides applied to control established infections and to prevent infections from becoming established. The following report outlines the efficacy of many products tested under different levels of disease conditions. Methods Potatoes (cut seed) were planted at the Michigan State University Muck Soils Experimental Station, Bath, MI on 29 May into two-row by 25-ft plots (34-in. row spacing) replicated four times in a randomized complete block design. The two-row beds were separated by a five-foot unplanted row. Plots were irrigated as needed with sprinklers and were hilled immediately before sprays began. The center and outside guard double rows were inoculated (3.4 fl oz/25-foot row) with a zoospore suspension of Phytophthora infestans US8 biotype (insensitive to metalaxyl, A2 mating type) at 10 4 spores/fl oz on 23 Jul. Fungicides were applied weekly (unless otherwise stated) from 25 Jun to 13 Aug (9 applications) with an ATV rear-mounted R&D spray boom delivering 25 gal/A (80 p.s.i.) and using three XR11003VS nozzles per row. Weeds were controlled by hilling and with Dual 8E (2 pt/A on 5 Jun), Basagran (2 pt/A on 15 Jun and 5 Jul) and Poast (1.5 pt/A on 23 Jul). Insects were controlled with Admire 2F (20 fl oz/A at planting on 26 Jun), Sevin 80S (1.25 lb on 1 and 23 Jul), Thiodan 3EC (2.33 pt/A on 1 and 21 Aug) and Pounce 3.2EC (8 oz/A on 23 Jul). Plots were rated visually for percentage foliar area affected by late blight on 23, 31 Jul, 7, 14, 23 and 28 Aug when there was 100% foliar infection in the untreated plots. The relative area under the disease progress curve was calculated for each treatment. Vines were killed with Diquat 2EC (1 pt/A on 10 Sep). Plots (25 ft row) were harvested on 28 Sept and individual treatments were weighed and graded. Results (general) Late blight developed rapidly during August and untreated controls reached 85 - 95% foliar infection by 14 Aug. Botrytis cinerea and Alternaria solani developed during the last week of August, and potato plants in some treatments were severely infected. Most fungicide programs with seven-day application intervals applied as protectants reduced the level of late blight foliar infection significantly compared to the untreated control. Results are presented by trial blocks. In general yields were low due to late planting, extremely high late blight pressure and early desiccation of the plots. No significant tuber rot was detected 90 days after storage in any treatment. General Conclusion Under the conditions experienced at the research farm in 1999, it was clear that the initial applications of protectant fungicides are vital for effective control of potato late blight. Protectant products must be applied in order to build up a residual base to prevent initial infections of potato late blight. Trial 1. EVALUATION OF QUADRIS 2.08SC, FLUAZINAM AND BRAVO ZN WS 6SC MIXED PROGRAMS AND BRAVO ZN 6SC + SUPERTIN 80WP PROGRAMS FOR POTATO LATE BLIGHT CONTROL, 1999: Introduction Quadris 2.08SC contains azoxystrobin and was registered for use as a late blight and early blight fungicide in 1999. This trial compared programs of Quadris 2.08SC in alternation with Bravo WS 6SC and Fluazinam 5SC with Bravo WS 6SC ± SuperTin 80WP programs. Foliar disease (Table 1) Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 85 - 95% foliar infection by 20 Aug. Botrytis cinerea developed during the last week of Aug and potato plants in some treatments were severely infected. Final foliar late blight: Taking 36 days after inoculation (dai) as a key reference point, all fungicide programs with seven-day application intervals reduced the level of late blight foliar infection significantly compared to the untreated control. The two Quadris 2.08SC and Bravo ZN WS 6SC alternating programs and the standard Bravo ZN WS 6SC program were not significantly different (p = 0.05). However, the Quadris 2.08SC and Bravo ZN WS 6SC alternating program with Fluazinam 5SC had significantly (p=0.05) less foliar late blight than the Quadris 2.08SC and Bravo ZN WS 6SC alternating programs initiated with Quadris 2.08SC and the standard Bravo ZN WS 6SC program. Programs where the addition of Supertin 80WP (0.161b/A) to Bravo ZN WS 6SC was delayed by two weeks were not significantly different (p=0.05) but the program where the addition of Supertin was delayed by two weeks had significantly less (p = 0.05) foliar late blight at the end of the evaluation period than the standard Bravo ZN WS 6SC program. The season-long increasing rate Bravo ZN WS 6SC + Supertin 80WP had significantly (p = 0.05) less foliar late blight than the Bravo ZN WS 6SC alternating program but was not significantly different (p = 0.05) from the season-long highest rate program of the Bravo ZN WS 6SC + Supertin 80WP program (1.5 pt + 0.19 lb/A). A clear dose response was observed from the increased rates of Bravo ZN WS 6SC + Supertin 80WP programs however only the lowest (0.75 pt + 0.06 Ib/A) and highest rates (1.5 pt + 0.19 Ib/A) were significantly different (p = 0.05). RAUDPC: the average amount of foliar late blight over the season from inoculation to 36 dai was significantly reduced by all fungicide programs with seven-day application intervals compared to the untreated control. The program where the addition of Supertin was delayed by two weeks and the Bravo ZN WS 6SC + Supertin 80WP (1.5 pt + 0.19 lb/A) had significantly less foliar late blight than the Quadris 2.08SC and Bravo ZN WS 6SC alternating programs initiated with Quadris 2.08SC, the standard Bravo ZN WS 6SC programs and the Bravo ZN WS 6SC + Supertin 80WP (0.75 pt + 0.06 lb/A) season-long program. None of the other programs were significantly different (p = 0.05) from each other. Yield: In general yields were low due to late planting, extremely high late blight pressure and early desiccation of the plots. Quadris 2.08SC and Bravo ZN WS 6SC alternating programs the program where the addition of Supertin 80WP (0.161b/A) to Bravo ZN WS 6SC was delayed by two weeks and the season- long Bravo ZN WS 6SC 1.0 pt/A + Supertin 80WP 0.09 lb/A had significantly (p = 0.05)higher yields in the US 1 size grade than the untreated check. The Quadris 2.08SC and Bravo ZN WS 6SC alternating programs (initiated with Quadris 2.08SC) had significantly (p = 0.05)higher yields in the US 1 size grade than the program where the addition of Supertin 80WP (0.161b/A) to Bravo ZN WS 6SC was applied two weeks after the initial fungicide applications. There were no other significant differences (p = 0.05) between treatments in the US 1 size grade. The Quadris 2.08SC and Bravo ZN WS 6SC alternating programs (initiated with Quadris 2.08SC), the Quadris 2.08SC and Bravo ZN WS 6SC alternating program with Fluazinam 5SC, the program where the addition of Supertin 80WP (0.161b/A) to Bravo ZN WS 6SC was delayed by two weeks and the season-long Bravo ZN WS 6SC 1.0 pt/A + Supertin 80WP 0.09 lb/A had significantly (p = 0.05)higher total yield than the untreated check. There were no other significant differences (p = 0.05) between treatments in total yield. Phytotoxicity was not noted in any of the treatments. Conclusions and Recommendations Quadris 2.08SC applied at 0.8 pt/A can be recommended as an effective fungicide applied early within protectant protection programs in alternation with an appropriate residual fungicide for the control of foliar late blight. The addition of SuperTin 80WP to Bravo ZN WS 6SC improved late blight control in several combination types especially when it was applied after inoculation of P. infestans. All products are applied at full recommended rate, unless specified. No recommendations can be made for the application of any product at rates less than those tested. Table 1. Treatment and rate/acre Quadris 208SC 0.80 pt (A,C,E3).............................. Bravo ZN WS 6SC 1.5 pt (B,D,F,G,H,I) Final foliar disease (%) 36 dai 1 47.5 bc4 RAUDPC 2 max= 100 0-32 dai 9.3b Bravo ZN WS 6SC 1.5 pt (A,C,E,G,H,I)............... Quadris 2.08SC 0.8 pt (B,D,F) 37.5 ab 32.5 a Quadris 2.08SC 0.8 pt (A,D).................................... Fluazinam 5SC 0.42 pt (B,E) Bravo ZN WS 6SC 1.5 pt (C,F,G,H,I) Bravo ZN WS 6SC 1.5 pt (A,B,C,D,E,F,G,H,I).... 47.5 bc 33.8 a Bravo ZN WS 6SC 1.5 pt (A,B,C,D)....................... Bravo ZN WS 6SC 1.5 pt (E,F,G,H,I) + Supertin 80WP 0.16lb 37.5a 35.0a Bravo ZN WS 6SC 1.5 pt (A,B).................... Bravo ZN WS 6SC 1.5 pt (C,D,E,F,G,H,I) + Supertin 80WP 0.16 lb Bravo ZN WS 6SC 0.75 pt (A,B)............................ + Supertin 80WP 0.06 lb pt Bravo ZN WS 6SC 1.0 pt (C,D,E,F) + Supertin 80WP 0.09 lb pt Bravo ZN WS 6SC 1.5pt (G,H,I) + Supertin 80WP 0.19 lb pt Bravo ZN WS 6SC 0.75 pt (A,B,C,D,E,F,G,H,I)... + Supertin 80WP 0.06 lb pt Bravo ZN WS 6SC 1.0 pt (A,B,C,D,E,F,G,H,I).... + Supertin 80WP 0.09 lb pt Bravo ZN WS 6SC 1.5pt (A,B,C,D,E,F,G,H,I)...... + Supertin 80WP 0.19 lb Untreated......................................................... 51.3c 42.5abc 32.5a 100d 8.5ab 7.3ab 9.8b 6.3a 7.8ab 7.8ab 9.8b 7.5ab 6.0a 19.2c Yield (cwt/acre) US1 Yield (cwt/acre) Total 115 a 100 ab 83 abc 94 abc 107 ab 231 a 207 ab 213 a 200 ab 216 a 82 bc 190 ab 94 abc 196 ab 89 abc 101 ab 91 abc 66 c 194 ab 210 a 192 ab 154 b 1 Days after inoculation with Phytophthora infestans, US8, A2. 2 RAUDPC, relative area under the disease progress curve calculated from the day of inoculation to the last evaluation of late blight. 3 Application dates: A= 23 Jun; B= 1 Jul; C= 8 Jul; D= 15 Jul; E= 22 Jul; F= 30 Jul; G= 7 Aug; H= 14 Aug; I= 21 Aug. 4 Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Trial 2. EVALUATION OF CGA 279202 50WDG, ULTRA FLOURISH 4EC + DITHANE 75DF, BRAVO ZN WS 6SC + CHAMP 4.6FL ALTERNATED WITH DITHANE 75DF + AGRITIN 80WP AND PENNCOZEB 75DF-BASED PROGRAMS FOR POTATO LATE BLIGHT CONTROL, 1999 Introduction Novartis are developing a novel strobilurine, CGA 279202 50WDG which was tested in this trial in programs in combination and alternated with Dithane 75DF. Ridomil Gold is recommended in Michigan for the control of tuber pathogens such as pink rot and Pythium leak. Soil applications of Ridomil Gold were tested in this trial along with the more traditional application recommendations for both products. In addition, programs with Ultra Flourish 4EC + Dithane 75DF, new formulations of Champ and Agritin 80WP were tested along with Penncozeb 75DF programs alone and in combination with Quadris 2.08SC. Additional Methods Ridomil 2EC was applied to the soil after planting in treatments 4 and 5 in Table 2. Foliar disease (Table 2) Final foliar late blight: Taking 36 days after inoculation (dai) as a key reference point, all fungicide programs with seven-day application intervals reduced the level of late blight foliar infection significantly compared to the untreated control. The Ridomil Gold 4EC 0.1 pt/A at planting followed by CGA 279202 50WDG 0.251b/A mixed with or alternated with Dithane 75DF 2.0 lb/A and the Ultra Flourish 4EC 0.38 pt/A + Dithane 75DF 2.0 lb/A programs gave significantly better control of final foliar late blight than other programs in this trial. The Bravo ZN WS 6SC + Champ 4.6FL alternated with Dithane 75DF 2.0 lb/A + Agritin 80WP 0.19 lb/A and the Bravo ZN WS 6SC 1.5 pt/A+ Ultra Champ 37.5DF 2.5 lb/A programs were not significantly different from the various Penncozeb 75DF-based programs. RAUDPC: the average amount of foliar late blight over the season from 0 to 36 dai was significantly reduced by all fungicide programs with seven-day application intervals compared to the untreated control. The Ridomil Gold 4EC 0.1pt/A at planting followed by CGA 279202 50WDG 0.251b/A mixed with or alternated with Dithane 75DF 2.0 lb/A and the Ultra Flourish 4EC 0.38pt/A + Dithane 75DF 2.0 lb/A programs gave significantly better control of foliar late blight over the season than other programs in this trial. Yield: In general, yields were low due to late planting, extremely high late blight pressure and early desiccation of the plots. There were no other significant differences between treatments in the US 1 or total size grade. Phytotoxicity was not noted in any of the treatments. Conclusions and Recommendations CGA 279202 50WDG (Flint 50WDG) mixed with or alternated with Dithane 75DF 2.0 lb/A should be recommended as an effective fungicide program for the control of foliar late blight. Ultra Flourish 4EC + Dithane 75DF programs should be recommended as an effective fungicide program for the control of foliar late blight. The inclusion of Ridomil Gold EC + Bravo WS 6SC in preventative strategies should continue to be recommended for effective control of foliar late blight. Penncozeb 75DF programs should be recommended as an effective fungicide program for the control of foliar late blight. All products are applied at full recommended rate, unless specified. No recommendations can be made for the application of any product at rates less than those tested. Table 2. Treatment and rate/acre Bravo ZN WS 6SC 1.5 pt (B, D, F, H)3...................... + Champ 4.6FL 2.67 pt Dithane 75DF 2.0 lb (C,E,G,I) + Agritin 80WP 0.19 lb Bravo ZN WS 6SC 1.5 pt (B,C,D,E,F,G,H,I)......... + Ultra Champ 37.5 DF 2.5 lb Dithane 75DF 2.0 lb (B,C,D,E,F,G,H,I)............... + Ultra Flourish 4EC 0.38 pt Ridomil Gold 4EC 0.10 pt (A).............................. CGA 279202 50WDG 0.25 lb (B,D,F,H) + Nufilm 0.125EC 1.0 pt Dithane 75DF 2.0 lb (C,E,G,I) Ridomil Gold 4EC 0.1 pt (A)................................... CGA 279202 50WDG 0.25 lb (B,C,D,E,F,G,H,I) + Nufilm 0.125 EC 1.0 pt +Dithane 75DF 2.0 lb Penncozeb 75DF 1.0 lb (B).................................... Penncozeb 75DF 1.67 lb (C,D,E,F,G) Penncozeb 75DF 2.0 lb (H, I) Penncozeb 75DF 1.0 lb (B,D)................................ Quadris 2.08SC 0.8 pt (C,E,G) Penncozeb 75DF 1.67 lb (F,H) Penncozeb 75DF 2.0 lb (I,J) Final foliar disease (%) 36 dai1 d4 56.3 RAUDPC2 max = 100 0 - 36 dai 1 9.8 c Yield (cwt/acre) Yield (cwt/acre) US1 239 a Total 345 a 58.8 d 10.3 c 237 a 350 a 28.8 ab 5.0 ab 264 a 392 a 27.5 a 4.3 a 259 a 362 a 33.8 ab 4.3 a 229 a 331 a 45.0 bc 7.8 bc 221 a 314 a 58.8 d 9.8 c 236 a 338 a Untreated.............................................................. 100 e 32.3 d 181 a 272 a 1 Days after inoculation with Phytophthora infestans, US8, A2. 2 RAUDPC, relative area under the disease progress curve calculated from the day of inoculation to the last evaluation of late blight. 3 Application dates: A= 26 May; B= 23 Jun; C= 1 Jul; D= 8 Jul; E= 15 Jul; F= 22 Jul; G= 30 Jul; H= 7 Aug; I= 14 Aug; J= 21 Aug. 4 Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Trial 3. EVALUATION OF EQUUS 6SC AND MANZATE 75DF + SUPERTIN 80WP PROGRAMS FOR POTATO LATE BLIGHT CONTROL, 1999 Introduction Griffin are introducing a new product in 2000, Equus 6SC (chlorothalonil). Combinations and alternating programs of Equus 6SC with Manzate 75DF, Supertin 80WP and Kocide 4.5FL at different rates and timings within protectant strategy programs were evaluated for the control of foliar and tuber blight. In addition, Manex II was evaluated for the control of foliar blight. Additional method Supertin was added to Diquat in some treatments at desiccation. Foliar disease (Table 3) Late blight developed slowly after inoculation then rapidly during Aug, and untreated controls reached 85 - 95% foliar infection by 20 Aug. Botrytis cinerea developed during the last week of Aug and potato plants in some treatments were severely infected. Final foliar late blight: Taking 36 days after inoculation (dai) as a key reference point, all fungicide programs with seven-day application intervals reduced the level of late blight foliar infection significantly compared to the untreated control. The mixed programs initiated by either Manzate 75DF 2.0 lb/A or Equus 6SC and continued with Manzate 75DF 2.0 lb/A + Supertin 80 WP 0.16 lb/A (6 applications) and the Equus 6SC 1.5 pt/A + Kocide 4.5LF 2.67 pt/A had the lowest final foliar late blight of all programs but were not significantly different from any other programs except Manex II 4SC 3.0 pt/A which had significantly more foliar late blight. RAUDPC: the average amount of foliar late blight over the season from 0 to 36 dai was significantly reduced by all fungicide programs with seven-day application intervals compared to the untreated control. None of the other programs were significantly different from each other. Yield: In general, yields were low due to late planting, extremely high late blight pressure and early desiccation of the plots. All programs, except the Equus 6SC 1.5 pt/A + Kocide 4.5 LF 2.67 pt/A program, had significantly higher yields in the US 1 size grade than the untreated check. There were no significant differences between fungicide programs in the US 1 size grade. All programs, except the Equus 6SC 1.5 pt/A + Kocide 4.5 LF 2.67 pt/A, Equus 6SC 1.5 pt/A, Equus 6SC 1.5 pt/A + Equus 0.135SC 0.06 pt/A and the Equus 6SC 1.5 pt/A (applications 1-3) followed by Manzate 75WP 2.0 lb/A + Supertin 80WP 0.16 lb/A (applications 4-9) followed by Supertin 80WP 0.16 lb/A + Diquat 36.4EC 1.0 pt/A at desiccation, followed by Kocide 4.5 LF 2.67 pt/A 3 days prior to harvest program, had significantly higher total yield than the untreated check. There were no other significant differences between fungicide programs in total yield. Phytotoxicity was not noted in any of the treatments. Conclusions and Recommendations Manzate + Supertin should be recommended as an effective fungicide combination for the control of foliar late blight. Equus 6SC combinations and alternating programs of Equus 6SC with Manzate 75DF, Supertin 80WP and Kocide 4.5FL at different rates and timings within protectant strategy programs should be recommended as an effective fungicide combination for the control of foliar late blight. All products are applied at full recommended rate, unless specified. No recommendations can be made for the application of any product at rates less than those tested. Table 3. Treatment and rate/acre Equus 6SC 1.5 pt (A,B,C,D,E,F,G,H,I 3) ............................... Equus 6SC 1.5 pt (A,B,C,D,E,F,G,H,I).................. ........ . + Kocide 4.5LF 2.67 pt Final foliar disease (%) 36 dai 1 43.8 ab4 41.3 ab Manex II 4SC 3.0 pt (A,B,C,D,E,F,G,H,I)........................... 53.8 b Manzate 75WP 2.0 lb (A,B,C)..................................... .......... Manzate 75WP 2.0 lb (D,E,F,G,H,I) + Supertin 80WP 0.16 lb Supertin 80WP 0.23 lb + Diquat 36.4 EC 1.0 pt (J) Kocide 4.5LF 2.67 pt (K) 36.3 a RAUDPC 2 max = 100 0 - 32 dai 9.5 a 8.3 a 10.0 a 7.0 a Yield (cwt/acre) US1 207 a 193 ab 252 a 230 a Total Yield (cwt/acre) 305 ab 297 ab 351 a 371 a Equus 6SC 1.5 pt (A,B,C)..................................................... Manzate 75WP 2.0 lb (D,E,F,G,H,I) + Supertin 80WP 0.16 lb Supertin 80WP 0.23 lb + Diquat 36.4EC 1.0 pt (J) Kocide 4.5LF 2.67 pt (K) Equus 6SC 1.5 pt (A,C, E,G, I).............. .............................. Manzate 75WP 2.0 lb (B,D,F,H) Equus 6SC 1.5 pt (A,B,C).................................................... Equus 6SC 1.5 pt (D,E,F,G,H,I) + Supertin 80WP 0.16 lb Supertin 80WP 0.23 lb + Diquat 36.4 EC 1.0 pt (J) Kocide 4.5LF 2.67 pt (K) 32.5 a 6.5 a 217 a 310 ab 45.0 ab 9.3 a 241 a 347 a 41.3 ab 7.5 a 217 a 321 a Untreated ................................................................................... 100 c 22.0 b 123 b 215 b 1 Days after inoculation with Phytophthora infestans, US8, A2. 2 RAUDPC, relative area under the disease progress curve calculated from the day of inoculation to the last evaluation of late blight. 3 Application dates: A= 23 Jun; B= 1 Jul; C= 8 Jul; D= 15 Jul; E= 22 Jul; F= 30 Jul; G= 7 Aug; H= 14 Aug; I= 21 Aug; J= 10 Sep; K= 15 Sep. 4 Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Trial 4. EVALUATION OF QUADRIS 2.08SC BASED PROGRAMS, CHLOROTHALONIL(ECHO AND BRAVO) BASED PROGRAMS AND OXIDATE SC PROGRAMS FOR POTATO LATE BLIGHT CONTROL, 1999 Introduction The effect of initiating programs with either Quadris or Bravo ZN was also evaluated with Quadris 2.08 SC applied at both the recommended rates for early blight and late blight control. In addition, an increasing rate of Bravo ZN WS 4.2SC was compared with the Echo 6SC and Echo ZN 6.25SC, chlorothalonil products. Foliar disease (Table 4) Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 85 - 95% foliar infection by 20 Aug. This trial experienced very high late blight pressure. Botrytis cinerea developed during the last week of Aug and potato plants in some treatments were severely infected. Final foliar late blight: Taking 36 days after inoculation (dai) as a key reference point, all fungicide programs with seven-day application intervals, except the Oxidate SC 8.0 pt/A program, reduced the level of late blight foliar infection significantly compared to the untreated control. The final amount of foliar late blight at the final evaluation date was not significantly different between any other treatments except that the Bravo ZN WS 6SC 1.0 pt/A with Quadris 2.08SC 0.8 pt/A program had significantly more foliar late blight than the increasing rate of Bravo ZN WS 6SC program and the Echo ZN 6.25SC 2.13 pt/A program. RAUDPC: The average amount of foliar late blight over the season from 0 to 36 dai was significantly reduced by all fungicide programs with seven-day application intervals compared to the untreated control. The Oxidate SC 8.0 pt/A program had a significantly higher RAUDPC than all other fungicide programs. Yield: In general, yields were low due to late planting, extremely high late blight pressure and early desiccation of the plots. All of the fungicide programs except Oxidate SC 8.0 pt/A had significantly higher yields in the US 1 size grade than the untreated check. Echo ZN WS 6SC and Echo 6SC programs had significantly higher yields in the US 1 size grade than the Oxidate 6SC 8.0 pt/A program. There were no other significant differences between treatments in the US 1 size grade. Only the Echo 6SC program had significantly higher total yield than the untreated check. There were no other significant differences between treatments in total yield. Phytotoxicity was not noted in any of the treatments. Conclusions and Recommendations Bravo ZN and Echo 6SC and Echo ZN 6.25SC should be recommended as effective fungicides for the control of foliar late blight applied on a 7day schedule. The effect of initiating the late blight control program with either Bravo ZN or Quadris had no effect on late blight development and it is recommended that the program could be started with either fungicide. The effect of increasing the rate of Quadris 2.08SC from 0.4 to 0.8 pt/A within a protectant program had no effect on late blight control and hence the lower of the two rates is adequate within a seven-day management strategy to control late blight. All products are applied at full recommended rate, unless specified. No recommendations can be made for the application of any product at rates less than those tested. Table 4. Treatment and rate/acre Bravo ZN WS 6SC 0.5 pt (A,B3) Bravo ZN WS 6SC 1.0 pt (C,D,E) Bravo ZN WS 6SC 1.5 pt (I,J,K,L) ............................. ... Final foliar disease (%) 36 dai 1 53.8 a4 RAUDPC 2 max = 100 0 - 36 dai 9.5 a Yield (cwt/acre) Yield (cwt/acre) US1 122 ab Total 235 ab Quadris 2.08SC 0.8 pt (A,C,E,J,L)......................... Bravo ZN WS 6SC 1.5 pt (B,G,I,K) ... 58.8 ab 10.8 a 131 ab 239 ab Bravo ZN WS 6SC 1.0 pt (A,C,E,J,L)................... Quadris 2.08SC 0.8 pt (B,G,I,K) ... 62.5 b 10.5 a 133 ab 244 ab Quadris 2.08SC 0.4 pt (A,C,E,J,L)........................ Bravo ZN 4 SC 1.5 pt (B,G,I,K) ... 58.8 ab 11.5 a 144 ab 263 ab Bravo ZN WS 6SC 1.5 pt (A,C,E,J,L)................... Quadris 2.08SC 0.4 pt (B,G,I,K) ... 60.0 ab 11.3 a 144 ab 251 ab Quadris 2.08SC 0.4 pt (A,E).................................... Bravo ZN WS 6SC 1.0 pt (B,C) Bravo ZN WS 6SC 1.5 pt (H,I,J,K,L) ... 57.5 ab 10.2 a 136 ab 240 ab Bravo ZN WS 6SC 1.5 pt (A,B,C,D,E,I,J,K,L)..... ... 60.0 ab Echo ZN 6.25SC 2.13 pt (A,B,C,D,E,I,J,K,L)....... .. 53.8 a Echo 6SC 1.5 pt (A,B,C,D,E,I,J,K,L)..................... ... 60.0 ab 12.0 a 10.2 a 12.3 a Oxidate SC 8.0 pt (A,B,C,D,E,F,G,H,I,J,K,L)....... ... 95.5 c 23.3 b Oxidate SC 8.0 pt (A,B,C,D,E,I,J,K,L)................... + Bravo ZN WS 6SC 1.5 pt 53.8 a 9.3 a 127 ab 155 a 148 a 98 bc 139 ab 258 ab 242 ab 278 a 200 ab 235 ab Untreated..................................................................... 100 c 29.5 c 71 c 187 b 1 Days after inoculation with Phytophthora infestans, US 8, A2. 2 RAUDPC, relative area under the disease progress curve calculated from the day of inoculation to the last evaluation of late blight. 3 Application dates: A= 23 Jun; B= 1 Jul; C= 8 Jul; D= 15 Jul; E= 22 Jul; F=23 Jul; G=24 Jul; H=25 Jul; I= 30 Jul; J= 7 Aug; K= 14 Aug; L= 21 Aug. 4 Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Trial 5 EVALUATION OF RATE RESPONSE OF ACROBAT 50WP + BRAVO WS 6SC AND TATTOO 6.25SC PROGRAMS FOR POTATO LATE BLIGHT CONTROL, 1999 Introduction Reduced rates of Tattoo C and Acrobat MZ were compared to the standard Bravo WS program in this trial for the control of foliar blight. Additional Methodology Two program initiation dates were compared, the first initiated on the accumulation of 10 late blight disease severity values (DSV) and the second initiated on the accumulation of 20 DSV. The DSV were accumulated using the Wallin model measured from an in-canopy Spectrum Instruments Weather Sation with remote cellular modem access Foliar disease (Table 5) All fungicide programs with seven-day application intervals reduced the level of late blight foliar Late blight developed slowly after inoculation then rapidly during Aug and untreated controls reached 85-95% foliar infection by 20 Aug. Botrytis cinerea developed during the last week of Aug and potato plants in some treatments were severely infected. Final foliar late blight and RAUDPC: Applications of most treatments at increasing rates initiated at 10DSV tended to result in better late blight control than their corresponding treatments initiated at 20DSV. However, the differences were not always statistically significant (p = 0.05). Applications of all treatments at increasing rates initiated at 10DSV: Taking 36 days after inoculation (dai) as a key reference point, all fungicide programs with seven-day application intervals reduced the level of late blight foliar infection significantly compared to the untreated control except the two lowest application rates of Tattoo C 6.25SC programs initiated at 10DSV. There were significant (p = 0.05) differences between Bravo WS 6SC (full application rate), Acrobat 50WP + Bravo WS 6SC and Tattoo C 6.25SC (applied at 0.25, 0.5, 0.75 and 1.0 of full application rate). Generally, the lowest application rates of Acrobat 50WP + Bravo WS 6SC and Tattoo C 6.25SCgave significantly poorer late blight control than the 0.75 and 1.0 application rates. There were no significant (p = 0.05) differences between Bravo WS 6SC (full application rate), Acrobat 50WP + Bravo WS 6SC and Tattoo C 6.25SC applied at 0.75and 1.0 of full application rate. Applications of all treatments at increasing rates initiated at 20DSV: all fungicide programs with seven-day application intervals reduced the level of late blight foliar infection significantly compared to the untreated control. Only the full application rates of Acrobat 50WP + Bravo WS 6SC and Tattoo C 6.25SC resulted in levels of late blight control achieved with 0.5 of the full application rate when the programs were initiated earlier. Yield: In general yields were low due to late planting, extremely high late blight pressure and early desiccation of the plots. There were few treatments with significant differences (p = 0.05) between fungicide programs in the US 1 size grade although generally the higher rate programs had higher yields. There were no significant differences (p = 0.05) between fungicide programs in total yield. Phytotoxicity was not noted in any of the treatments. Conclusions and Recommendations Tattoo C and Acrobat 50WP + Bravo WS applied season long at about 0.75 -1.0 of the recommended full rate of application gave similar levels of control to the standard programmed application of Bravo WS, full season when started at either 10 DSV. At lower rates under high disease pressure, late blight control was much reduced. Tattoo C and Acrobat 50WP + Bravo WS applied season long at about 0.75 -1.0 of the recommended full rate of application gave similar levels of control to the standard programmed application of Bravo WS, full season when started at either 20 DSV. At lower rates under high disease pressure, late blight control was much reduced. Delaying the initiation of the protectant programs resulted in lower levels of late blight control at corresponding treatments and rates regardless of the products used. All products are applied at full recommended rate, unless specified. No recommendations can be made for the application of any product at rates less than those tested. Table 5. Treatment and rate/acre Bravo WS 6SC 1.5 pt (A,B,C,D,E,F,G,H) Final foliar disease (%) 36 dai1 50.0 abc RAUDPC2 max = 100 0-32 dai 11.6 abc US1 194 ab Tattoo C 6.25SC 0.58 pt (A,B,C,D,E,F,G,H) Tattoo C 6.25SC 1.15 pt (A,B,C,D,E,F,G,H) 93.3 82.5 hi 20.2 f 172 ab fghi 15.7 cde 198 ab Tattoo C 6.25SC 1.75 pt (A,B,C,D,E,F,G,H) 46.3 ab Tattoo C 6.25SC 2.3 pt (A,B,C,D,E,F,G,H) 42.5 a 9.7 a 9.0 a 80.0 fgh 15.2 cde Yield (cwt/acre) Yield (cwt/acre) Total 316 a 280 a 320 a 344 a 336 a 304 a 202 a 206 a 206 a Bravo WS 6SC 1.5 pt (C,D,E,F,G,H) 68.8 cdefg Acrobat 50WP 0.1 lb (A,B,C,D,E,F,G,H) + Bravo WS 6SC 0.25 pt Acrobat 50WP 0.2 lb (A,B,C,D,E,F,G,H) + Bravo WS 6SC 0.5 pt Acrobat 50WP 0.3 lb (A,B,C,D,E,F,G,H) + Bravo WS 6SC 0.75 pt Acrobat 50WP 0.4 lb (A,B,C,D,E,F,G,H) + Bravo WS 6SC 1.0 pt Tattoo C 6.25SC 0.58 pt (C,D,E,F,G,H) Tattoo C 6.25SC 1.15 pt (C,D,E,F,G,H) Tattoo C 6.25SC 1.75 pt (C,D,E,F,G,H) Tattoo C 6.25SC 2.3 pt (C,D,E,F,G,H) Acrobat 50WP 0.1 lb (C,D,E,F,G,H) + Bravo WS 6SC 0.25 pt Acrobat 50WP 0.2 lb (C,D,E,F,G,H) + Bravo WS 6SC 0.5 pt Acrobat 50WP 0.3 lb (C,D,E,F,G,H) + Bravo WS 6SC 0.75 pt Acrobat 50WP 0.4 lb (C,D,E,F,G,H) + Bravo WS 6SC 1.0 pt 63.8 bcdef 12.2 abc 198 ab 332 a 56.3 abcd 10.5 ab 196 ab 316 a 42.5 a 9.1 a 204 a 322 a 15.3 15.8 cde cdef 188 ab 204 a 14.3 bcde 176 ab 15.6 cde 181 ab 14.3 bcde ghi 16.8 178 ab 164 ab defgh defgh defgh cdefg 75.0 73.8 76.3 67.5 85.0 324 a 310 a 322 a 308 a 329 a 324 a 75.0 defgh 17.1 195 ab 337 a 75.0 defgh 15.2 cde 188 ab 334 a 62.5 bcde 13.1 bcd 190 ab 320 a def def Untreated 100 i 28.2 g 124 b 258 a 1 Days after inoculation with Phytophthora infestans, US8, A2. 2 RAUDPC, relative area under the disease progress curve calculated from the day of inoculation to the last evaluation of late blight. 3 Application dates: 10 Late blight severity values at A= 8 Jul; B= 15 Jul; C= 22 Jul; D= 30 Jul; E= 7 Aug; F= 14 Aug; G= 21 Aug; H= 28 Aug. 20 Late blight severity values at C= 22 Jul; D= 30 Jul; E= 7 Aug; F= 14 Aug; G= 21 Aug; H= 28 Aug. 4 Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Trial 6. Comparison of control of potato late blight (Phytophthora infestans) attained with Polyram and Curzate 60DF + Polyram in combination with adjuvants. Introduction This trial compared the contribution that different adjuvants made to late blight control when applied with a surface residual fungicide (Polyram 80DF) and with a translaminar/systemic fungicide (Curzate 60DF + Polyram 80DF). Additional Methods This trial block was not directly inoculated. The block was close to other trial blocks that had been inoculated as described in the general methods section. Foliar disease (Table 6) Late blight developed slowly after inoculation then rapidly during Aug, and untreated controls reached 85-95% foliar infection by 20 Aug. Botrytis cinerea developed during the last week of Aug and potato plants in some treatments were severely infected. Final foliar late blight: Taking 36 days after inoculation (dai) as a key reference point, Polyram 80DF 2.0 Ib/A, Polyram 80DF 2.0 Ib/A + Tactic SC 0.25 pt/A, Polyram 80DF 2.0 Ib/A + Activator SC 0.25 pt/A, Curzate 60DF 0.21 lb/A + Polyram 80DF 1.5 lb/A, Curzate 60DF 0.21 lb/A + Polyram 80DF 1.5 lb/A + Li700 SC 0.25 pt/A and Curzate 60DF 0.21 lb/A + Polyram 80DF 1.5 lb/A + Activator SC 0.25 pt/A were not significantly different from the untreated control. All other fungicide programs with seven-day application intervals reduced the level of late blight foliar infection significantly compared to the untreated control. However, no fungicide programs with or without adjuvants were significantly different from each other. RAUDPC: the average amount of foliar late blight over the season from 0 to 36 dai was significantly reduced by all fungicide programs with seven-day application intervals compared to the untreated control. However, no fungicide programs with or without adjuvants were significantly different from each other and in general late blight control was poor. Yield: In general, yields were low due to late planting, extremely high late blight pressure and early desiccation of the plots. The Curzate 60DF 0.21 lb/A + Polyram 80DF 1.5 lb/A + Tactic 0.25 pt/A program had significantly higher yields in the US 1 size grade than the untreated check and the Curzate 60DF 0.21 lb/A + Polyram 80DF 1.5 lb/A program. There were no other significant differences between treatments in the US 1 size grade and no other treatments had significantly higher yields in the US 1 size grade than the untreated check. Only the Polyram 80DF 1.5 lb/A program had significantly higher total yield than the untreated check. There were no other significant differences between treatments in total yield. Phytotoxicity was not noted in any of the treatments. Conclusions and Recommendations Curzate 60DF applied in combination with Polyram 80DF gave moderate control of late blight and could be recommended for control of potato late blight under moderately conducive late blight conditions. Polyram 80DF gave moderate control of late blight and could be recommended for control of potato late blight under moderately conducive late blight conditions. The addition of Tactic, Li700 or Activator 90 to Curzate 60DF + Polyram 80DF or Polyram 80DF programs season long made no significant difference to the level of control of late blight and their addition is not justified for late blight control, however, their addition did tend to reduce the level of foliar late blight. All products are applied at full recommended rate, unless specified. No recommendations can be made for the application of any product at rates less than those tested. Table 6. Treatment and rate/acre Polyram 80DF 2.0 lb (A,B,C,D,E,F,G,H,I)3........................ Polyram 80DF 2.0 lb (A,B,C,D,E,F,G,H,I)........................ + Tactic SC 0.25 pt Polyram 80DF 2.0 lb (A,B,C,D,E,F,G,H,I)........ ................ + Li700 SC 0.25 pt Polyram 80DF 2.0 lb (A,B,C,D,E,F,G,H,I)........... ....... + Activator 90SC 0.25 pt Curzate 60DF 0.21 lb (A,B,C,D,E,F,G,H,I)................. + Polyram 80DF 1.5 lb Curzate 60WP 0.21 lb (A,B,C,D,E,F,G,H,I)........................ + Polyram 80DF 1.5 lb + Tactic SC 0.25 pt Curzate 60WP 0.21 lb (A,B,C,D,E,F,G,H,I).............. + Polyram 80DF 1.5 lb+ Li700 SC 0.25 pt Curzate 60WP 0.21 lb (A,B,C,D,E,F,G,H,I)..... ................... + Polyram 80DF 1.5 lb + Activator 90SC 0.25 pt Final foliar disease (%) 36 dai 1 80.0 ab4 82.5 ab RAUDPC2 max = 100 0-32 dai 15.5 a 19.5 a Yield (cwt/acre) Yield (cwt/acre) US1 146 ab 120 ab Total 279 a 248 ab 78.8 a 17.5 a 149 ab 247 ab 81.3 ab 17.8 a 155 ab 253 ab 87.0 ab 20.8 a 102 b 217 ab 78.8 a 17.0 a 164 a 262 ab 86.3 ab 20.0 a 123 ab 231 ab 80.0 ab 17.5 a 134 ab 257 ab Untreated...................................................... ........................... 100 b 30.3 b 103 b 205 b 1 Days after inoculation with Phytophthora infestans, US8, A2. 2 RAUDPC, relative area under the disease progress curve calculated from the day of inoculation to the last evaluation of late blight. 3 Application dates: A= 23 Jun; B= 1 Jul; C= 8 Jul; D= 15 Jul; E= 22 Jul; F= 30 Jul; G= 7 Aug; H= 14 Aug; I= 21 Aug. 4 Values followed by the same letter are not significantly different at P = 0.05 (Tukey Multiple Comparison). Trial 7. Comparison of control of established potato late blight (Phytophthora infestans) attained with fungicides. Introduction This trial compared the efficacy of various fungicides with applied after late blight had started to develop within the crop. Three timings were evaluated, fungicide programs initiated (5 day interval, 3 applications) at a) 72 h before inoculation, b) 72 h after inoculation, c) when 1% and d) when 5% of the foliage showed late blight symptoms. Previous trials from 1995 - 1997 have shown that at infection levels above 5% foliar infection, no fungicides can contain the infection under continued conducive late blight conditions. Additional Methods Fungicides were applied on a 5 day interval for 15 days (3 applications). Fungicide applications were initiated at 4different timings a) 72 h before inoculation (72 hbi), b) 72 h after inoculation (72 hai), c) when plants were 1% infected and d) when plants were 3-5% infected. The first timing began on 20 July, the second on 26 Jul, the third on 1 Aug and the fourth on 3 Aug 1999. Foliar disease (Fig 1) Late blight developed rapidly during August and untreated controls reached 85-95% foliar infection by 14 Aug. Partial control of late blight was achieved when some of the fungicides were applied 72 hour before and after inoculation. No fungicide treatments gave control of late blight when the initiation of the control programs were delayed until 1 or 5% foliar infection. Chlorothalonil (Bravo WS6SC), dimethomorph (Acrobat 50WP) + chlorothalonil or + triphenyltin OH (Supertin 80WP), cymoxanil (Curzate 60DF) + chlorothalonil, propamocarb + chlorothalonil (Tattoo C 6.25SC), mancozeb (Manzate 75DF) + triphenyltin OH (full and double rate of application) programs all had significantly less late blight than the untreated control (RAUDPC) at each timing comparison. All other programs were not significantly different from the untreated plots. The mean infections were shown for each timing and indicate the overall level of infection at each timing comparison. The treatments initiated 72 hai had lower overall mean infection than any other initiation timing however the programs initiated 72 hbi had similar levels of late blight control. The programs initiated at 1 and 5% foliar infection had similar levels of late blight infection but were much greater than those programs initiated at 72 hai and 72 hbi. Conclusions and Recommendations Mancozeb (Manzate 75DF 2.0 Ib/A) + triphenyltin OH (Supertin 80WP 0.44 Ib/A, double rate of labeled application) applied 72 h after inoculation and repeated twice at 5 day intervals reduced late blight development more than any other treatment. This combination could be recommended for control of potato late blight under conducive late blight conditions after infection is known to have occurred and should be included as an emergency control program to prevent late blight from developing from infection loci. Chlorothalonil (Bravo WS6SC), dimethomorph (Acrobat 50WP) + chlorothalonil or + triphenyltin OH (Supertin 80WP), cymoxanil (Curzate 60DF) + chlorothalonil, propamocarb + chlorothalonil (Tattoo C 6.25SC), mancozeb (Manzate 75DF) + triphenyltin OH (full rate of application) programs all had significantly less late blight than the untreated control (RAUDPC) at each timing comparison. These combinations could be recommended for control of potato late blight under conducive late blight conditions after infection is known to have occurred within fields or areas where late blight is present. Non-preventative application of any fungicide for late blight control should not be considered for management of late blight. All products are applied at full recommended rate, unless specified. No recommendations can be made for the application of any product at rates less than those tested. Figure 1. The effect of fungicides on the average amount of foliar late blight over the 36 day infection period (RAUDPC) on containing established foliar late blight. Initial applications applied 72 hours before inoculation (72 hbi), 72 hours after inoculation (72 hai), at 1% visible foliar infection and at 5% visible foliar infection and re-applied at 5 day intervals for a total of three applications. Rates are lb/A active ingredient. Funding: MPIC Control of Seed-Borne Late Blight (Phytophthora infestans Mont. De Bary) Development from Treated Potato Seed-Pieces with Trichoderma atroaviride. W. W. Kirk1 and J. McBeath2 1 Department of Botany and Plant Pathology, Michigan State University, East Lansing, MI 48824, USA,2 Department of Agriculture, University of Alaska, Fairbanks. INTRODUCTION Potato late blight caused by Phytophthora infestans (Mont. De Bary) is the most important potato disease in North America.1 Control of late blight is traditionally achieved by cultural controls and crop protection strategies that rely on applications of foliar fungicides.2 Late blight is readily transmitted by seed-borne inoculum3,4 and consequently, immature stems and leaves may be exposed to late blight from infected seed pieces. Other seed-borne pathogens of potatoes, such as Fusarium spp. and Rhizoctonia solani, can be effectively controlled by application of fungicides to the seed piece.5,6 Similarly, prevention of establishment of late blight infection transmitted from infected to disease-free seed pieces by seed treatments has been demonstrated.7 Active ingredients in seed piece treatments may prevent early season establishment of late blight by persisting on the immature foliage after the plant has emerged from the soil.8 The objectives of this study were to determine the efficacy of T. atroaviride applied to potato seed­ pieces against potato late blight under different infection mechanisms. Experiments in controlled environments and in the field were conducted between 1998 and 1999 to establish the efficacy of a T. atroaviride along with a variety of fungicides applied to the seed-pieces in controlling tuber- borne and foliar phases of late blight. Three separate simulations of late blight infection mechanisms and potential prevention of late blight establishment are described: infection carry-over within tubers stored for seed and infected during seed cropping in the prior growing season, transmission of late blight between infected and non-infected seed-pieces during seed cutting, and infection of the immature canopy after exposure to aerial inoculum. MATERIALS AND METHODS 2.1 Selection and Preparation of Potatoes Seed tubers of potatoes(cv. Snowden) harvested from crops in Michigan with no record of foliar or tuber late blight were selected for freedom from other diseases and uniformity of size (35 - 55 mm diameter size grade). After harvest, the tubers were stored at 4°C in the dark for at least 80 days, then transferred to 18°C, (14 h photo-period) to break dormancy 9. Prior to storage the tubers were washed in distilled water, disinfected for 2 h in 2% commercial bleach solution (Clorox), dried and stored until used. The number of leaf initials at the time of seed treatment was established by counting the number of leaf initials on sprouts from apical, lateral and basal regions of the tuber under a dissecting microscope (n = 20 sprouts). Seed treatments were applied after inoculation. The timing of cutting of seed tubers into seed-pieces and application of seed-piece fungicides were dependent on the simulated infection mechanism and were described in the following sections. Seed-pieces were planted 48 - 72 h after the seed treatments were applied. 2.2 Experiment Design Experiments testing infection transmission mechanisms from seed-pieces infected during the seed production season, transmission of infection from infected seed-pieces to late blight free seed-pieces and infection of the immature canopy were conducted during each of three runs in controlled environments and in the field in 1998 - 99. The controlled environment experiments were carried out in temperature and humidity-controlled environment chambers. The chambers (3.4 m3) were situated within green houses and covered with 1mm transparent polyethylethene. Natural light was supplemented by high-pressure sodium lamps, 400w 14h-10h day-night. Relative humidity was maintained at greater than 90% by timer controlled humidifiers (Herrmidifier model 500). Temperature typically ranged between 15 - 24°C. Ten plants per treatment were used for each experiment in concurrent experiments. 2.2.1 Seed tuber infection simulation and inoculation This study examined the effect of seed treatments on suppressing transmission of P. infestans from infected seed tubers to emerging sprouts. Tubers were inoculated with a zoospore suspension (10 3 zoospores m1 -1) genotype of P. infestans US8 (insensitive to metalaxyl, A2 mating type) from cultures grown on rye agar plates10 for 14 days in the dark at 15°C. Sporangia were harvested from the petri dishes by rinsing the mycelial/sporangial mat in cold (4°C) sterile, distilled H2O 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 106 sporangia ml-1 using a hemacytometer. Tubers were inoculated with about 0.1 ml of the zoospore suspension (ca. 100 zoospores) injected to a depth of 2.0 mm below the periderm and 1.0 cm from the main apical sprout. The wound was covered with a smear of petroleum jelly to prevent desiccation. Seed treatments were applied 24 h after inoculation. 2.2.2 Transmission of infection at seed cutting simulation Transmission of late blight infection at seed cutting was simulated by cutting seed and immediately exposing the seed to late blight inoculum. 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, removed and seed treatments were immediately applied. The homogenate was prepared from 20 plate cultures (9 cm diameter x 15 mm depth petri plates). Each plate produced between 10 5 - 10 6 spores ml-1 from 50 ml of wash water. An estimate of the amount of mycelium from each plate was not attempted. 2.2.3 Foliar infection simulation and inoculation The effect of seed treatments applied to non-infected tubers on foliar infection was examined. Foliar late blight was evaluated on plants inoculated with late blight after the plants had emerged. After they reached the rapid expansion phase (15 days after emergence, 15 cm tall with an average of 10 main leaves on each stem), the plants in the chambers were inoculated with 1000 ml of a 103 zoospore ml-1 suspension, delivered as an aerosol. Plants were exposed to high relative humidity conditions (RH = 100%), for 8 h prior to inoculation to wet the leaves. In the field experiments all the rows were inoculated (100 ml 12 m-1 row) with a zoospore suspension (103 zoospore ml-1) on 27 July, 1999. 2.2.4 Application of seed treatments (controlled environment and field experiments). Conventional seed treatment fungicides were applied to whole seed for use in the transmission of late blight from seed harvested the previous season. Seed tubers cut once were used for experiments to examine transmission during seed-cutting and protection of the immature canopy from aerial inoculum. Treatment trade names, application rates, manufacturers and chemical compositions are listed in Table 1. Seed treatments were applied when sprouts had broken dormancy. Sprouts averaged 15 leaf initials at the time of application (15.1 ± 0.45, n = 20), with about eight internodes between the base of the sprout and the first emerged leaf. The amount of fungicide required to treat the seed tubers was calculated from manufacturer recommended seed application rates, e.g. for dust (D) formulations. Transmission of late blight from a) infected seed and b) seed infected at cutting included inoculated and untreated seed tubers (negative control) and uninoculated and untreated seed tubers (positive control). The foliar infection experiments included potato plants that developed from seed tubers that were untreated and uninoculated (positive control). TABLE 1. Fungicides applied: trade names, manufacturers and active ingredients Trade name Maxim MZ 0.5D Trichoderma atroaviride 2.3 Field experiments Rate of application kg/tonne 0.5 1.0 Manufacturer Active ingredient Novartis 0.5% fludioxinil + 6% mancozeb empty table cell empty table cell The field experiments were planted at the Michigan State University Muck Soils Research Station, Bath, MI on 1 June, 1999, in five-row by five plant plots, 86 cm row spacing, total 25 plants, replicated six times in a randomized complete block design. Plots were irrigated as needed with sprinklers and were hilled immediately after emergence. No foliar fungicides were applied to the field experiment. Weeds were controlled by hilling and with metolachlor at 0.46 kg/ha 10 dap (days after planting), bentazon salt at 0.12 kg/ha, 20 and 40 dap and sethoxydim at 0.05 kg/ha, 58-60 dap. Insects were controlled with imidacloprid at 1.4 kg/ha at planting, carbaryl at 1.4 kg/ha, 31 and 55 dap, endosulfan at 0.98 kg/ha, 65 and 87 dap and permethrin at 0.56 kg/ha, 48 dap. 2.4 Data collection Plant emergence was rated in all experiments. Rate of emergence was calculated as the relative area under the plant emergence progress curve (RAUEPC) with a modification of the method used to calculate the relative area under the disease progress curve (RAUDPC) The AUEPC was calculated by adding the area under the linear progression of number of plants emerged between each successive estimation of emergence from planting to full emergence. The RAUEPC was calculated by dividing the measured AUEPC by the maximum AUEPC (100 x duration of the emergence period, from planting to full or final plant number emerged). 14. Plots (field) and individual plants in each treatment (controlled environments) were rated visually for percent leaf area with symptoms of late blight. The average amount of disease that developed over the disease progress period was expressed as the relative area under the disease progress curve (RAUDPC) which is used extensively to measure disease progress over a given time period11,12,13 15. The area under the disease progress curve (AUDPC) was calculated by adding the area under the linear progression of disease between each successive estimation of disease from inoculation to 100% plant death The RAUDPC is calculated by dividing the measured AUDPC by the maximum AUDPC (100 x duration of the epidemic, from inoculation to 100% plant death). 14 14. In the controlled environment foliar inoculation experiment, the ratio of infected to non-infected leaves was calculated with respect to the position of the leaf on the main stem at 14 days after inoculation. Number of leaves with symptoms was evaluated at each main stem leaf position above the soil surface, and the ratio of infected to non-infected leaves was calculated for each treatment. The first leaf above the soil was counted as leaf one. A leaf was considered infected if it had one or more late blight lesions on any of the leaflets or the petiole. The stem that was apically dominant [i) had most main stem leaves, ii) and had the greatest stem diameter] was selected for the evaluation on each of 10 separate plants. Data were analyzed by two-way analysis of variance and means compared at p = 0.05 level of significance by a multiple range comparison of means (Tukey, SigmaStat). Data were combined in the controlled environment experiments (1998-99) because the variation between separate treatments in different runs of the experiment were not different. RESULTS Controlled environment experiments Seed tuber infection simulation and inoculation Plant emergence did not exceed 20%, except in the uninoculated untreated control, regardless of the seed treatment (Figure 1). With some of the treatments, fewer plants emerged than the untreated control but differences were not statistically significant (p = 0.05). The rate of emergence (RAUEPC) and number of plants emerged after tubers were inoculated by injection and treated with any seed treatment was significantly lower than the untreated and uninoculated control (Figure 1). 3.1.2 Transmission of infection at seed cutting simulation The rate of emergence (RAUEPC) and number of plants emerged was not significantly different than the untreated and uninoculated control or the untreated and inoculated control for any inoculated seed treatment combinations (Figure 2). 3.1.3 Foliar infection simulation and inoculation Tubers that were not inoculated but were treated with a seed treatment emerged at a rate (RAUEPC) not significantly different than the uninoculated and untreated control in the previously described simulations i.e. final stand count was 80 - 100% for all treatments and rate of emergence (RAUEPC) about 0.35 - 0.40. The number of plants emerged was not significantly different between treatments. Initial foliage symptoms of late blight were significantly (p = 0.05) reduced by all seed-piece treatments ten days after inoculation in comparison with the untreated and inoculated check, however stem infection was not significantly reduced (Figure 3). The rate of late blight development (RAUDPC) after inoculation over a 21 day period was significantly higher in all treatments in comparison with the untreated and uninoculated control but not significantly different from the untreated and inoculated control (Figure 3). The number of infected leaves was determined at each main stem leaf position above the soil surface, and the ratio of infected to non-infected leaves was calculated for each treatment 14 days after inoculation (Figure 4). In some of the plants that developed from treated seed, the lower leaves on the main stem had a lower ratio of infected leaves in positions 1 to about 3 (leaf 1 being the leaf closest to the soil and 6 a mid­ stem leaf). The ratio of infected leaves among treatments was similar to the untreated plots above leaf position 6. T. atroaviride and fludioxinil + mancozeb seed-piece treatments had low ratios of infected leaves from the lower canopy (leaves 1- 3), (Figure 4). For all treatments, the ratio of diseased to non-diseased leaves was lower in leaf positions above 10 (Figure 4). 3.2 Field Experiments 3.2.1 Tuber inoculation experiments The number of emerged plants that developed from inoculated seed-pieces did not exceed 25%, regardless of the seed treatment (Figure 5). All treatments and the untreated inoculated control had significantly less plants emerge in comparison with the untreated and uninoculated control (Figure 5). No late blight was observed on plants that emerged. 3.2.2 Transmission of infection at seed cutting simulation Rate of emergence (RAUEPC) and percent emergence of plants after the cut surfaces of seed tubers were inoculated and treated with T. atroaviride and fludioxinil + mancozeb seed-piece treatments was not significantly different than that of the untreated and uninoculated control (Figure 5), but was higher than that of untreated and inoculated tubers. T. atroaviride and fludioxinil + mancozeb and the untreated and uninoculated control had close to 100% emergence than the untreated and inoculated control Figure 5). No plants with lesions caused by late blight were observed after emergence of plants that developed from tubers exposed to the cut face inoculation. 3.2.3 Foliar inoculation experiments No significant difference (p = 0.05) was observed in rate of emergence or final plant stand between any treatments emerged from treated seed tubers21 days after planting, final stand count was 90 - 100% for all treatments and rate of emergence (RAUEC) about 0.5 - 0.55. Foliar late blight progress (RAUDPC) after inoculation of the immature canopy, in plants that developed from untreated and treated seed-pieces (all fungicide treatments) was not significantly higher (p = 0.05) in comparison with the untreated/uninoculated control which became infected soon after the inoculation and late blight developed to a final infection level of 100% and RAUDPC of about 0.30 for all treatments. DISCUSSION Potato seed piece treatments are useful for the control of seed-borne diseases such as black scurf and stem canker (Rhizoctonia solani), silver scurf (Helminthosporium solani) and dry rot (Fusarium spp)5, 16, 17. These results confirm that the addition of active ingredients that are effective in the management of foliar late blight e.g. mancozeb to existing seed treatments expands their spectrum of activity. However, it is the first indication that a biological control agent T. atroaviride, is as effective as conventional fungicides for the control of seed-borne late blight. The simulation of different phases of infection of potato late blight identified effective treatments for seed-borne late blight and aerial infection of the immature canopy. Pathogens such as silver scurf, black scurf and dry rot, typically rely on seed infection to establish a moderate level of sprout infection, thereby initiating the seasonal epidemic on stems either above or below ground 18. Severe infection of the sprout with P. infestans results in premature sprout death and non-emergence3. No seed treatments effectively controlled late blight spread inside the tuber. The application of seed treatments to infected seed did not enhance emergence and did not prevent disease developing on some of the emerged sprouts. Internal tuber infections were not controlled with the seed treatments tested. The low number of emerged plants and decreased rate of emergence indicated that sprouts were becoming infected and killed prior to emerging from the soil. The mechanism of infection of sprouts by P. infestans has not been fully described but a study by Kirk et al. (unpublished) has shown that infection of developing sprouts on potato tubers is initiated in connecting tissue at the point of attachment of the sprout to the mother tuber. The development of products for late blight control is currently focused on products to prevent the transmission of the disease at seed cutting7. Simulation of cut surface spread of late blight from tuber to tuber in this study confirmed that cut surfaces exposed for as little as 30 seconds to late blight inoculum are readily infected. The cut surface is readily infected by P. infestans7 but is also accessible to the active ingredients and biocontrol agents contained in the seed treatments. Infection may have been partially inhibited by the T. atroaviride and mancozeb component of the seed treatments. Mancozeb does not penetrate foliar tissue and the pathogen evades the fungicide once penetration has taken place19 therefore mancozeb may not move far from the site of application on tuber tissue. The cut surface of the tuber may allow mancozeb to move sufficiently far inside the cut tuber to prevent the establishment of late blight and prevent the infection of sprouts. However, T. atroaviride is systemic in plant tissue (reference please) and may prevent late blight infection of sprouts in cut seed where the application of the seed treatment is delayed in blight infected seed-lots. It is not expected that T. atroaviride applied as a seed-piece treatment would be fully effective and the risk of plants emerging from the soil with late blight remains even when seed treatments with components effective against late blight are included in the formulation. The reduced rate of emergence of plants after treatment with seed treatments that did not contain mancozeb was evident. A slower rate of emergence may enable the late blight infection to become established and either kill the developing sprout or allow the infection to be carried above ground and initiate a new crop infection. These results confirm other findings7 that pre-cutting and use of seed treatments (specific and unspecific for late blight) may increase the risk of blight spreading from the seed to the sprout and ultimately to foliage. Secondary spread of late blight between plants may occur at an early stage in canopy development. The effect of biological and conventional seed treatments may endure sufficiently to help reduce the vulnerability of immature leaves to infection by P. infestans. Seed-piece treatments reduced overall disease in the immature canopy after foliar inoculation with P. infestans in controlled environment experiments. This was especially true for leaves near the base of the stem, but not all leaves were protected from late blight. Leaves that had a reduced ratio of infection were at the base of the main stem and may have been exposed to the seed treatments at the time of application. Immature leaf primordia were less than 0.5 cm in length at the time of treatment20 and biocontrol agents and fungicides applied to seed may accumulate on tuber structures such as developing sprouts. The accumulated biocontrol agents and fungicides are likely to be stored, dispersed and taken up (if systemic) by the developing leaf, stolon and root primordia present on these sprouts. Redistribution of active ingredients may result in effective dose accumulations on the developing leaves and internodes. Leaves at the base of the stem in some varieties are less susceptible to late blight infection than leaves close to the flower21. Corresponding field studies designed to examine the effect of seed treatments on subsequent foliar infection did not confirm the controlled environment studies. The quantity of P. infestans inoculum and conducive environment in the field studies allowed infection of all unprotected foliage and resulted in rapid and complete plant death. Seed health and quality is of paramount importance to seed and commercial growers in potato crop production6. Although it is not possible at present to be completely certain that a potato seed lot is 100% free of late blight, it is prudent to plant seed that meets established seed certification standards. The application of appropriate seed treatments to healthy seed may seem counterintuitive. However, the potential for late blight to establish itself in young post-emergence foliage before prophylactic fungicide applications begin suggests that additional early season protection may be warranted in potato growing areas with a history of late blight. Seed treatment applied to healthy seed may provide some protection against early season late blight and may persist sufficiently to overlap with the beginning of conventional foliar fungicide applications, providing more complete protection. Some seed treatment fungicides, such as the fludioxinil + mancozeb and thiophanate-methyl + cymoxanil + mancozeb have systemic and non-systemic fungicide components. These formulations suppressed late blight development in newly emerged plants in controlled environments. It was encouraging that T. atroaviride attained levels of late blight control similar to fludioxinil + mancozeb. The precise timing of application of seed treatments in relation to seed cutting, sprout development and timing of planting requires further study. ACKNOWLEDGMENTS This research was funded in part by the Michigan Agricultural Experiment Station, the Michigan Potato Growers Commission, Gustafson, Inc. and Novartis Crop Protection, Inc. Mention of a brand or trade name does not constitute an endorsement. REFERENCES 1. Inglis, D.N., Johnson, D.A., Legard D.E., Fry W.E., & Hamm P.B., Relative resistance of potato clones in response to new and old populations of Phytophthora infestans. Plant Disease, 80 (1996): 575 - 78. 2. Lacy, M.L. & Hammerschmidt, R., Diseases of potato: late blight. Extension Bulletin Michigan State University, East Lansing, MI 48824 (1995) E-1802. 3. Kadish, D. & Y. Cohen., Over seasoning of metalaxyl-sensitive and metalaxyl-resistant isolates of Phytophthora infestans in potato tubers. Phytopath., 82 (1992):887-889 4. Lambert, D.H.& Currier, A. I., Differences in tuber rot development for North American clones of Phytophthora infestans. American Pot. J., 74 (1997):39 - 43. 5. Kirk, W.W., Leadbeater, A. J., Burgess, P. J., Wale, S. J. & Oxley, S.J.P., Control of potato stem and skin diseases with fenpiclonil seed treatments in Northern Britain. Proc. Crop Protection in Northern Britain Conf., (1993) 313-318. 6. Secor, G.A. & N.C. Gudmestad. 1993., Handling and planting seed tubers In R.C. Rowe ed. Potato Health Management, APS Press, St. Paul, MN, (1993) pp. 27-34. 7. Lambert, D.H., Currier A.I. &.Olanya, M., Transmission of Phytophthora infestans in cut potato seed. American J. of Pot. Research, 75 (1998): 257 - 263. 8. Fillipov, A.V., Kuzentzova, M. A, Barlyuk T.I.,. Rogozhin A. N & Pyushpeki V. D., Influence of potato tuber treatments with fludioxinil on development of fungal diseases. Proc. Brighton Crop Prot. Conference Proc. Pests and diseases, 1 (1996) 269 - 74. 9. Plissey, E.S., Maintaining tuber health during harvest, storage and post-storage handling. In R.C. Rowe ed. Potato Health Management, APS Press, St. Paul, MN, (1993) pp. 41 - 54. 10. Deahl, K L., DeMuth S. P., Sinder, S. L, & Rivera-Pena, A., Identification of mating types and metalaxyl resistance in North American populations of Phytophthora infestans. American Pot. J. 72(1) (1995): 35-50. 11. Kirk, W.W., B.J. Kitchen, & J.M. Stein, Late blight control with fungicides. Fungicide and Nematicide Tests, 51 (1996): 159 - 167. 12. Kirk, W.W., Stein J.M., B.J. Kitchen & Niemira, B.A., Late blight control with fungicides. Fungicide and Nematicide Tests, 52 (1997): 149. 13. Kirk, W.W., Stein, J.M., Schafer, R.L. & Niemira B.A., Evaluation fungicides for potato late blight control. Fungicide and Nematicide Tests, 1999, (In press, 8 reports). 14. Campbell, C. L. & Madden, L. V., Introduction to Plant Disease Epidemiology, 1990. John Wiley and Sons, New York. 15. Pritchard, P. M., Hausbeck, M. K. & Heins, R. D., The influence of diurnal temperatures on the postharvest susceptibility of Poinsettia to Botrytis cinerea. Plant Disease, 80 (1998): 1011 - 1014. 16. Hide, G. A. & Lapwood, D.H., Disease aspects of potato production. In P.M. Harris ed. The Potato Crop: the scientific basis for improvement, 1982, pp 409 - 439. Chapman and Hall, London. 17. Frazier, M. J., Shetty, K. K., Kleinkopf, G. E. & Nolte, P., Management of silver scurf (Helminthosporium solani) with fungicide seed treatments and storage practices. American J. of Pot. Res., 75 (1998): 129- 135. 18. 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. 19. Schwinn, F. J. & Margot, P., Control with chemicals. In D. S. Ingram and P. H. Williams, eds. Phytophthora infestans, The Cause of Late Blight of Potato. Advances in Plant Pathology, Vol. 7(1991): 225-265. 20. Kirk, W.W., Davies, H.V. & Marshall, B., The effect of temperature on the initiation of leaf primordia in developing potato sprouts. J. of Exp. Botany, 36:171(1985), 1634 - 1643. 21. Carnegie, S. F. & Colhoun, J., Susceptibility of potato leaves to Phytophthora infestans in relation to plant age and leaf position. Phytopath., 104 (1982): 157 - 67. Figure 1. Final plant stand (max = 1) and rate of plant emergence (max = 1) of potato plants that emerged from fungicide-treated seed pieces. Seed tubers inoculated by sub- peridermal injection with P. infestans 24 h before seed treatments applied (averages of 3 experiments). Figure 2. Final plant stand (max = 1) and rate of plant emergence (max = 1) of potato plants that emerged from fungicide-treated seed pieces. Seed tubers inoculated by exposure of cut surface of seed tuber to mycelial/rye agar homogenate of P. infestans 0.5 h before seed treatments applied (averages of 3 experiments). Figure 3. Foliar and stem late blight infection of potato plants that emerged from fungicide- treated seed pieces. Plants inoculated with P. infestans by foliar aerosol of zoospore suspension 10 days after emergence and evaluated 14 days after inoculation (averages of 3 experiments). Figure 4. Ratio of infected:healthy potato leaves inoculated with P. infestans in relation to leaf position on the main stem (averages of 3 experiments). Foliar infection of potato plants that emerged from fungicide-treated seed pieces. Plants inoculated with P. infestans by foliar aerosol of zoospore suspension 10 days after emergence and evaluated 14 days after inoculation (averages of 3 experiments). Figure 5. Final plant stand (max = 1) and rate of plant emergence (max = 1) of potato plants that emerged from fungicide-treated seed pieces. Injected - seed tubers inoculated by sub- peridermal injection with P. infestans 24 h before seed treatments applied, cut face - seed tubers inoculated by esposure of cut surface of seed tuber to mycelial/rye agar homogenate of P. infestans 0.5 h before seed treatments applied(averages of 3 experiments). MPIC Funding: MSU Potato Precision Ag Team Spatial and Temporal Dynamics of Potato Production Sites in Relation to Precision Agriculture and Integrated Crop Management Systems Potato Precision Ag Team: • Roger Brook, Agricultural Engineering (coordinator) • George Bird, Entomology (nematodes, verticillium and potato early die) • Darryl Warncke, Crop & Soil Sciences (soil fertility) • Scott Swinton, Agricultural Economics (profitability assessment) • Dave Lusch, Center for Remote Sensing (analysis of aerial imagery) • Mark Otto, Agri-Business Consultants (crop management) • Nate Hough, Agricultural Engineering (data analysis) • Don Smucker, Montcalm Co. Extension (extension liaison; information dissemination) • Rich Hodupp, St. Joesph Co. Extension (extension liaison; information dissemination) Project Goal: To evaluate the value and utility of precision agriculture practices, systems and concepts in the production of potatoes grown under Michigan conditions Specific Objectives: • to investigate the relationship between tuber quality (yield, size and market quality) and soil quality (soil properties, fertility, nematodes, disease, particularly in relation to supplemental calcium • to understand the role of precision agriculture technologies in reducing within field variation for Michigan potatoes Funding: MPIC for field sampling; In-Kind for sample analysis and field management; MAES/MSUE for technical support (starting fall 1999). Research sites have been established in two potato production areas: • Montcalm Co. — two fields of about 60 acres each; one planted to potatoes (Pikes) in 1999 and the other to be planted to potatoes in 2000; primary soils are yellow sand mapped as Mancelona loamy sand and black sand mapped as Gladwin loamy sand and Palo sandy loam; we anticipate planting the 1999 field to potates in 2001 • St. Joseph Co. — a 440 acre block, with potatoes in a three year rotation with seed com; approximately 1/3 of the block is planted to potatoes each year; we anticipate planting the 1999 potato area to potatoes in 2002 Much of our efforts this year have centered on field characteristics that relate to the 1999 and 2000 potato crops. • elevation (topographic) mapping - the research sites were mapped with a high- accuracy GPS system to establish both field elevation and electrical conductivity (EM38) characteristics. • fertility sampling - in Montcalm Co., the 1999 field was sampled by the grower during the fall, 1998 on a 2.5-acre grid; the 2000 field was sampled on a 1-acre grid. The total St. Joseph site was sampled on a 1-acre grid, including all major and minor nutrients. • potato early die risk assessment - the 2000 field in Montcalm Co. was sampled on a 1-acre grid for nematodes and verticillium. Calcium vs. Fumigation (Montcalm Co. research site) The 1999 research site in Montcalm Co. was used to conduct an experiment to look at the interaction of calcium and fumigation. Fumigation was applied to the southern half of the field fall 1998 using metham applied at 37.5 gal/acre. The field was planted using Pike variety potatoes on May 1-3, 1999. Supplemental calcium (pelletized gypsum) was applied to the whole field at 200 lb/acre at cultivation, with the exception of a strip of about 10-acres in each of the fumigation treated and not-treated sections of the field (see Figure 1). Additional calcium was supplied by calcium nitrate applied as a top-dress. Prior to harvest, sample points were identified for locations of tuber samples to be taken for tuber quality analysis. There were four sample points identified for each of the four treatment combinations (see Figure 1). During harvest, potato yield was monitored on the harvester using a HarvestMaster yield monitoring system. At each of the 16 sampling locations, samples of approximately 50- tubers each of large tubers (larger than 3 inches) and normal tubers (1-1/2 - 2-1/2 inches) were taken for quality analysis. Soil samples were also taken at each sampling location. For each sample, 25 tubers were cut and evaluated for internal quality problems unique to the Pike variety. The tubers in each sample were classified as either no-defects, moderate internal defects or severe internal defects. Calcium (both pulp and peel) were determined for each sample for the no-defect tubers and for the defect tubers. The normal tubers were analyzed for sugars, chip color and total chip defects (both defect and non-defect tubers). Table 1 illustrates the treatment combination effects for percent non-defect tubers. Table 1. Average of %no-defect tubers by treatment for Montcalm potato field 1999. empty table cell All Samples Added Calcium No Added Calcium Fumigated normal Fumigated large Not Fumigated normal Not Fumigated large All Samples normal All Samples large 95 54 96 78 96 66 79 39 86 67 83 53 87 47 91 73 89 60 Preparations for Montcalm Co. 2000 Potatoes Calcium management is one focus of this project. The research site has relatively high calcium values compared to county averages (average 1,393 lbs. Ca per acre; range <500 to 3000). In most of the field, we would not expect a yield response from supplemental calcium applications. We are interested in the effects of supplemental calcium on tuber quality. Magnesium levels are low. Soil test values below 75 are considered deficient. Supplemental Mg applications will need to be made. Magnesium and potassium also can interact with calcium and need to be considered when making supplemental calcium applications. Since the Mg values are low, we may be able to manipulate treatments to evaluate magnesium's impact on calcium uptake. Previous research has shown that plant parasitic nematodes are distributed as aggregates or clumps in crop fields. Prior to development of geo-referencing technologies of precision agriculture, it was very difficult to implement the type of stratified sampling required for optimal nematode analysis. The nematode data illustrates an area of about 5 acres of severe root-lesion risk in the 62 acre field. The Verticillium data illustrates an area of about 2 acres in the field with a population density >16 colonies per gram of soil. When the root-lesion nematode and Verticillium data are incorporated into a Potato Early-Die disease risk index, 16 acres of the 62 acre field are shown to have a high or severe PED risk for the next potato crop. Figure 1. Field layout and sample points for the Montcalm field 1999; the bottom section of the field was fumigated, the top section was not; strips without supplemental calcium are indicated; available calcium values from sampling fall 1998. Field Boundary Start Location: Latitude: 43.43744131 Longitude: -84.87099467 No. of Observations: 30 Minimum Ca: 300 Maximum Ca:3100 Average Ca: 1197 Figure 2. Potato yield map (cwt/acre) for the Montcalm field 1999; average yeild 417 cwt/acre; each of the three center legend ranges represents 20% of the data points; data points greater than 500 cwt/acre probably represent start/stop points or areas where 16-rows were harvested, but the yield monitor was set to 8-rows; data points less than 300 cwt probably represent row ends. Appendix Table A. Soil test results for the Montcalm field, sampled at harvest 1999. % No Defect % No Defect Large Tubers Normal Tubers Sample * 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 88 80 64 84 40 84 72 68 40 52 40 24 44 84 44 44 96 88 88 92 76 96 100 92 76 84 76 80 92 92 100 96 pH 5.6 5.4 5.3 5.2 5.6 5.6 5.5 5.8 5.6 6.1 5.8 5.9 5.7 5.8 5.9 5.8 Pounds per Acre Pounds per Acre P 190 254 254 190 247 200 190 200 190 154 240 262 247 190 174 166 K 326 379 305 284 284 358 200 242 221 263 337 253 170 200 221 274 ppm Ca 2000 2100 700 500 800 1000 600 700 500 800 900 800 700 800 800 800 ppm Mg 236 245 95 74 147 209 126 158 126 209 218 209 255 218 189 218 * Samples 1, 6, 7, 8, 13, 14, 15, 16 had supplemental calcium; samples 9-16 were fumigated Appendix Table B. Tuber pulp and periderm calcium for the Montcalm field 1999. Large Tubers Large Tubers % No Defect Periderm Ca (%DM basis) Pulp Ca (%DM basis) Normal Tubers Normal Tubers Periderm % No Defect Ca (%DM basis) Pulp Ca (%DM basis) Sample * 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 d 2 nd d 3 nd d 4 nd d 5 nd d 6 nd d 7 nd d 8 nd d 9 nd d 10 nd d 11 nd d 12 nd d 13 nd d 14 nd d 15 nd d 16 nd 0.04 0.054 0.033 0.044 0.040 0.041 0.035 0.041 0.033 0.033 88 80 88 64 96 d ** 0.141 1 nd ** empty table cell 0.153 0.135 empty table cell 0.184 0.042 0.041 0.041 0.049 empty table cellempty table cell 88 0.163 empty table cell0.132 0.139 empty table cell0.175 0.106 empty table cellempty table cellempty table cellempty table cell0.130 0.094 empty table cell0.089 0.198 empty table cell0.191 0.133 empty table cell0.147 96 84 84 76 92 40 0.102 empty table cell 0.083 0.115 empty table cell 0.124 0.123 empty table cell 0.131 0.112 empty table cell 0.128 0.115 empty table cell 0.106 72 68 100 92 84 52 40 40 empty table cellempty table cell 76 empty table cell0.112 0.099 empty table cell0.087 0.125 empty table cellempty table cellempty table cellempty table cell0.176 0.079 empty table cell0.079 0.103 empty table cell0.133 0.073 empty table cell0.129 0.091 empty table cell0.101 0.119 empty table cell0.117 0.074 empty table cell 0.113 0.118 empty table cell 0.100 0.117 empty table cell 0.113 0.130 empty table cell 0.130 0.119 empty table cell 0.183 0.113 empty table cell 0.114 0.093 empty table cell 0.103 0.03 0.032 0.026 0.037 0.037 0.035 0.030 0.041 0.042 0.037 0.029 0.045 0.035 0.033 empty table cell0.171 0.157 empty table cell0.154 100 44 44 76 92 96 92 24 44 80 84 0.050 0.060 0.030 0.049 0.038 0.045 0.036 0.037 0.048 0.046 0.036 0.049 0.039 0.046 0.033 0.024 0.047 0.032 0.038 0.038 0.037 0.029 0.040 0.028 0.036 0.036 0.044 0.034 0.034 0.052 empty table cellempty table cell empty table cellempty table cell * Samples 1, 6, 7, 8, 13, 14, 15, 16 had supplemental calcium; samples 9-16 were fumigated ** d = tubers from sample that had defects; nd = tubers from sample without defects Appendix Table C. Sugar content analysis and chip score and rating for normal size tuber samples for the Montcalm field 1999. Sample * %No Defect Chip Score % Color Defects % Total Defects empty table cell empty table cellempty table cell empty table cell empty table cell empty table cell empty table cellempty table cell empty table cell empty table cell 13.3 0 13.3 20 100 13.3 0.234 0.346 0.168 0.003 0.004 0.003 * Samples 1, 6, 7, 8, 13, 14, 15, 16 had supplemental calcium; samples 9-16 were ** d = tubers from sample that had defects; nd = tubers from sample without defects Sucrose Rating 0.34 0.243 0.316 0.269 0.232 0.206 0.262 0.262 0.366 0.305 0.32 0.288 Glucose Rating 0.004 0.003 0.004 0.002 0.003 0.002 0.003 0.003 0.005 0.002 0.005 0.003 0.191 0.284 0.314 0.161 0.211 0.206 0.196 0.249 0.226 0.161 0.234 0.224 0.209 0.29 0.2 0.003 0.003 0.002 0.003 0.005 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.002 0.003 0.003 50 6.7 50 13.3 50 13.3 75 10 50 13.3 100 0 20 17 0 50 10 50 0 33.3 0 50 0 25 0 50 20 0 6.7 50 13.3 0 13.3 0 10 0 13.3 0 0 20 0 0 0 6.7 0 0 0 0 0 0 0 0 0 20 88 88 96 1 empty table cell 1 1 empty table cell 1 1 empty table cell 1 1 empty table cell 1 1 empty table cell 1 1 empty table cell 1 92 76 96 100 84 92 76 empty table cell 1 1 empty table cell 1 1 empty table cell 1 1 empty table cell 1 1 empty table cell 1 1 empty table cell 1 1 empty table cell 1 1 empty table cell 1 76 92 92 80 100 empty table cell 1 1 empty table cell 1 96 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 d ** nd ** d nd d nd d nd d nd d nd d nd d nd d nd d nd d nd d nd d nd d nd d nd d nd fumigated Misc. Funding: MSU Potato Precision Ag Team Calcium And Metham Effects on Potato Tuber Yield and Quality George Bird, Dept of Entomology Darryl Warncke, Dept. of Crop and Soil Sciences New technologies are enabling measurement of field and soil properties and potato tuber yields and quality by site specifically. A better understanding of the landscape, soil and biological factor effects on potato growth, development and subsequent tuber quality and yield will improve production of quality potato tubers. Factors that may influence tuber yield and quality are insufficient available calcium in soil and the early die complex generally involving verticillium and parasitic nematodes. This study focused on the effects of supplemental calcium and fumigation and was located in the NW 1 range of the Montcalm Potato Research Farm. All plots were sampled to determine the soil pH, available nutrient status, and the nematode population. The soil fertility data are presented in appendix table A. Two main treatments were applied separately and in combination (Table 1). In April after the soil had warmed up the soil was fumigated with 75 gallons of metham per acre. The soil was opened up with secondary tillage two weeks prior to planting. Calcium (294 lb/A) as calcium sulfate (1000 lb/A) was broadcast and incorporated prior to planting. Additional calcium (100 lb/A) as calcium nitrate was top-dressed directly over the row at tuber initiation. Planting occurred on May 14. Tubers were harvested on September 24. Samples of 2.5 to 3.25 inch diameter tubers were placed in 50°F storage. In December, 25 tubers were sliced, inspected for defects and fried for chips. Another sample of 24 tubers were bruised in an octagonal tumbler. After being at room temperature for 3 days the tubers were peeled and inspected for bruises. RESULTS Fumigation with metham had a significant effect on tuber yield and tuber size (Table 1). Calcium had a much smaller effect. The combination of metham and calcium resulted in the greatest yield and highest percent of over 3 inch tubers. The NW1 range has considerable variability in topography that resulted in considerable variability in yield data and a significant replication effect. The replications (3 and 4) with the lowest yields had the lowest elevation and some plots were quite wet at times during the growing season. Herbicide application was also missed in some plots in these two replicates which had an adverse effect. The tubers grown in fumigated soil had significantly less stem-end discoloration and vascular discoloration (Table 3). Supplemental calcium had little effect on the occurrence the various defects. Table 1. Potato (cv Snowden) yield and quality as influenced by supplemental calcium and metham. Treatment Check Calcium x metham z Calcium + metham Lsd .05 Total Yield 266 297 436 424 85 >3” 6.2 8.1 18.1 13.9 6.2 Size Distribution Size Distribution 2-3” 71.3 71.3 70.9 72.6 <2" Size Distribution Specific Gravity 1.074 1.073 1.075 1.075 19.1 16.8 8.1 10.2 ns 8.8 ns x Calcium sulfate was broadcast and incorporated at 1000 lb/A. In addition 100 lb calcium per acre, as calcium nitrate, was topdressed directly over the row. x metham was injected at 75 gallons per acre. Table 2. Location (replicate) effect on potato (cv Snowden) yield and quality the calcium and metham treatments. Replicate 1 north 2 3 4 5 6 south Lsd .05 Total Yield 404 372 236 349 387 388 139 Size Distribution >3” 14.2 14.1 3.5 10.5 12.8 14.3 Size Distribution Size Distribution <2” 2-3” 71.2 10.8 69.3 12.6 67.0 25.6 73.0 12.6 9.2 75.0 73.6 10.4 9.2 7.3 10.0 Specific Gravity 1.075 1.075 1.068 1.074 1.076 1.076 .002 x Calcium sulfate was broadcast and incorporated at 1000 lb/A. In addition 100 lb calcium per acre, as calcium nitrate, was topdressed directly over the row. z metham was injected at 75 gallons per acre. Table 3. Influenced of supplemental calcium and metham on potato (cv Snowden) tuber and chip quality. Treatment Check Calcium x metham z Calcium + metham Lsd .05 Bruise Index 1.93 2.29 2.48 2.20 ns Stem-End Discoloration 2.3 2.0 0.8 1.2 Vascular Discoloration 2.7 3.3 0.7 1.0 1.2 1.1 Hollow Heart 0.5 0.7 1.0 0.0 0.9 Chip Color 1.4 1.6 1.6 1.6 ns x Calcium sulfate was broadcast and incorporated at 1000 lb/A. In addition 100 lb calcium per acre, as calcium nitrate, was topdressed directly over the row. z metham was injected at 75 gallons per acre. Appendix Table A. Soil pH and extractable P, K, Ca and Mg values for all plots sampled prior to application of treatments. Plot Rep Trtmt. pH BpH 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 6 4 3 1 2 4 2 1 3 1 2 4 3 1 3 4 2 1 2 3 4 3 4 1 2 5.5 5.9 5.9 6.1 6.0 6.1 6.0 6.1 5.9 5.7 5.8 5.9 5.9 5.9 6.0 6.0 6.1 6.2 6.2 5.8 5.9 6.1 6.3 6.0 6.7 6.8 6.8 6.9 6.9 6.9 6.9 7.0 6.9 6.8 6.7 6.8 6.9 6.9 6.9 7.0 7.0 7.0 7.0 6.8 6.7 6.9 7.0 6.9 P 458 388 376 388 352 364 388 330 302 330 408 392 342 352 330 320 320 342 330 424 528 376 342 320 K 270 300 320 320 330 370 360 330 330 320 470 370 320 280 340 270 300 290 350 370 430 370 290 260 Ca 490 760 690 380 860 820 840 920 860 850 1030 870 810 550 610 720 740 760 780 720 900 740 700 580 Mg 105 106 146 124 166 135 75 155 145 146 170 150 195 124 108 121 96 135 118 139 127 173 154 153 Bray Pl extractable P. Ammonium acetate extractable K, Ca and Mg. MPIC and Federal Funding: MSU Potato Storage Team POTATO STORAGE EXPERIMENTS Two Decades of Progress in Technology and Management Round 1 :1986-1989 Dr. Burt Cargill, Dr. Roger Brook, Todd Forbush, Keith Tinsey, John Mills Agricultural Engineering Department, Michigan State University Storage Location: Sandyland Farms, Montcalm Co. Objective: test the influence of different rates of airflow on the performance of chip potatoes in storage. Methods Construct three experimental storage bins • 8' x 8' floor area, 18' high • independent ventilation • control using Fancom 1056 computer • different airflow rates 1.5, 3.0 & variable 0 - 3.0 CFM/cwt Fill in the fall with Atlantic variety potatoes • sample bags placed at three levels for total weight loss • temperature sensors at four levels in the pile • sample from three levels for sugar content and chip color Storage temperature management • pre-conditioning: 60°F at 92-95% RH • cool down: 1 - 2°F per week to 50°F • holding: 50°F at 95% RH Results for 1988-1989 Storage Season empty table cell ventilation, cfm/cwt Bin #1 1.5 Bin #2 Bin #3 3.0 variable*** 67 0 0.028 0.74 8.8 61 2 0.011 0.45 7.0 62 8 0.023 1.1 10.0 68 3 0.023 0.90 7.9 65 0 0.032 0.49 9.3 4' level color * 4' level appearance ** 4' level % glucose 4' level sucrose rating 4' level weight loss, % 8' level color * 8' level appearance ** 8' level % glucose 8' level sucrose rating 8' level weight loss, % 12' level color * 12' level appearance ** 12' level % glucose 12' level sucrose rating 12' level weight loss, % * Agtron scale calibrated red mode 0 and 90 ** quality criterea: 0 = excellent; 15 = not acceptable *** average of variable ventilation rate was 1.0 58 1 0.032 0.70 5.6 64 3 0.017 0.41 5.6 61 0 0.039 0.70 6.1 0.63 0 0.028 0.65 6.2 CFM/cwt Conclusions • Three years of research • Average weight loss not a function of ventilation rate • Weight loss more uniform at higher ventilation rates • Pre-conditioning management strategy produced high quality potatoes from 50°F storage after 135 days • Environmental control was effectively carried out using the Fancom environmental control computer More Information Michigan Potato Research Report. 1987, 1988. Simulated potato storage research. Forbush, T.D. 1989. Influence of Ventilation Rate on Potato Quality Out-of Storage. M.S. Thesis, Forbush, T.D. and Brook, R.C. 1993. Influence of airflow rate on chip potato storage management. Michigan State University. Am. Potato J. 70:869-883. Round 2: 1990-1991 Dr. Roger Brook, Robert Fick Agricuultural Engineering Department, Michigan State University Dr. Ray Hammerschmidt Botany and Plant Pathology Department, Michigan State University Storage Location: Bishop Potato Farms, Bay Co. Objective: To store Atlantic and W855 (Snowden) potatoes for an extended season. Methods Move two research bins to Bay Co. • modify bins to have same fan (capable of 3.0 cfm/cwt) • install new Fancom 656 storage controller • fill one bin with Atlantic potatoes and one with W855 (Snowden) potatoes Environmental control goals • Atlantic desired pile temperature 50°F • W855 desired pile temperature 45°F • maximum difference between pile and ventilation temperature 4°F • maximum difference between any two pile temperature sensors 2°F • relative humidity controlled above 90% Dates and Sampling Sep. 26, 1990 • Harvest • Cooling begins Oct. 31, 1990 • Sprout inhibitor Nov. 12, 1990 • Holding begins Jan 22, 1991 • Experiment ends Apr. 9, 1991 Sampled bi-weekly for sugar content, wound healing ability and Fusarium resistance Figure 1. Schematic cross-section of potato storage research bins Conclusions • no significant difference in sucrose or glucose sugar contents between levels in any research bin • all samples had acceptable fry color • both varieties exhibited near constant ability to suberize and to restrict dry rot developemnt; after January the ability of both varieties to carry out these two functions declined • Snowden appeared to have somewhat greater wound healing ability • Snowden potatoes appeared to sprout earlier than the Atlantics, suggesting a need for faster cooling Recommendations • Snowden potatoes at 45°F respond similar to Atlantic potatoes stored at 50°F • uniform and gradual temperature changes are important for maintaining potato color and quality through extended storage • temperature of the cooling air should be maintained above 42°F at all times Round 3: 1992-1993 Dr. Roger Brook, Robert Fick Agricultural Engineering Department, Michigan State University Storage Locations: Bishop Potato Farms, Bay Co. and lott Seed Potato Farm, Kalkaska Co. Objective: investigate storage temperature management on out-of storage quality of Snowden potatoes Methods Move the remaining research bin to Kalkaska Co. • modify bins to have same fan (capable of 3.0 cfm/cwt) • install new Fancom 656 storage controller • fill one bin with Atlantic potatoes Desired storage temperature • Bin #1 - 45°F • Bin #2 — cool til color develops; warm til color disappears • Bin#3-40°F Environmental control goals • difference between pile sensors 0.5°F • difference between pile and ventilation air 4°F • minimum plenum temperature 42°F • relative humidity 95% Storage Dates and Paameters 1992-1993 empty table cell Bin #2 Bin #l Bay Co. 10/5/92 59 1.5 24 24 3 of 12 10/25/92 location harvest date harvest temp, °F ventilation rate fan run times, hr - suberization - cooling - holding start cooling cooling rate, °F/day 0.3 start holding holding temp, °F market date 12/9/92 45 3/31/93 Bay Co. 10/5/92 59 1.5 24 24 3 of 12 10/25/92 0.3 12/17/92 min 42 3/30/93 Bin #3 Kalkaska Co. 9/16/92 72 1.5 24 24 3 of 12 10/15/92 0.5 11/125/92 39 4/21/93 Results See figure on the following page for results from the 1992-1993 storage season. Snowden Storage Recommendations • wound healing at 55°F and 95% RH for 2 weeks • pre-condition at 55°F until color reaches desired level; glucose about 0.01% • cool tubers quickly at 0.5°F/day to a temperature of 50°F; uniform and gradual temperature changes are important for maintaining potato quality and color • maintain difference between pile temperature and ventilation air temperature at no more than 3°F • continue cooling to 45°F at a rate of 0.3°F/day, using ventilation air temperatures of no less than 43°F More Information Michigan Potato Research Report. 1993. Potato Storage Research. Fick, R.J. 1993. Experiments On The Long-Term Storage Of Chipping Potatoes. Ph.D. Thesis, Fick, R.J. and Brook, R.C. 1999. Threshold sugar concentrations in Snowden potatoes during storage. Michigan State University. Amer. J. Potato Res. 76:357-362. Figure 2. Temperature and sugar concentrations for samples taken during the 1992-1993 storage season (sucrose data was divided by 10 before plotting). Bin 1 (located at Bishop Farms) had a holding temperature of 45°F; bin 2 (located at Bishop Farms) had a holding temperature of 42°F; bin 3 (located at lott Farm) had a holding temperature of 40°F. Bins were not actively managed relative to sugars. Round 4: 1994-1997 Dr. Roger Brook Agricultural Engineering Department, Michigan State University Storage Location: Bishop Potato Farms Objective: monitor selected varieties during using different temperature management strategies. Methods During the summer of 1995, Bishop Potato Farms constructed a new storage facility. Within that storage, they designed four research bins similar to those used in the previous studies. These bins were used during the subsequent three storage seasons. 1995- 1996 Storage Season: Snowden variety potatoes were placed in bins 21 (desired holding temperature 42°F) and 22 (desired holding temperature 45°F). Lemhi Russet variety potatoes were placed in bin 23 and Pike variety potatoes were placed in bin 24. All the potatoes were grown in Bay Co. by Bishop Potato Farms. The storage bins were actively managed relative to sugar contents of the bi­ weekly tuber samples. The Lemhi Russet potatoes were marketed for french fry production in late December, 1995. The other potatoes were marketed for potato chips in early April, 1996. 1996- 1997 Storage Season: Snowden and Pike variety potatoes were grown in Montcalm Co. and in St. Joseph Co. The Snowden potatoes were stored in bins 21 and 22, with a desired holding temperature of 45°F. The Pike potatoes were stored in bins 23 and 24, with a desired holding temperature of 50°F. The storage bins were actively managed relative to sugar contents of the bi-weekly tuber samples. The Pike potatoes were marketed in mid-February, 1997. The Snowden potatoes were held into early June, but were not successfully marketed due to excess glucose content. 1997- 1998 Storage Season: Snowden variety potatoes were placed in bins 23 and 24. Selected numbered varieties were placed in bins 21 and 22. All potatoes were grown in Bay Co. by Bishop Potato Farms. The storage bins were actively managed relative to sugar contents of the bi-weekly samples. All potatoes were successfully marketed in late February, 1998. Results Potato sample data for the three storage seasons is presented in the figures on the following pages. Figure 3. Temperature and sugar contents for tuber samples taken during the 1995-1996 storage season. Top two lines are temperatures for the two bins with a range of 40-60°F; middle two lines are sucrose rating (divided by 10 before plotting); bottom two lines are glucose content. Bin 21 had Snowden potatoes with a desired holding temperature of 42°F; bin 22 had Snowden potatoes with a desired holding temperature of 45°F; bin 23 had Lemhi Russet ( LR) potatoes; and bin 24 had Pike potatoes. Figure 4. Temperature and sugar contents for tuber samples taken during the 1996- 1997 storage season. Top two lines are temperatures for the two bins with a range of 40-60°F; middle two lines are sucrose rating (divided by 10 before plotting); bottom two lines are glucose content. Bin 21 had Snowden potatoes grown in Montcalm Co. with a desired holding temperature of 45°F; bin 22 had Snowden potatoes grown in St. Joseph Co. with a desired holding temperature of 45°F; bin 23 had Pike potatoes grown in Montcalm Co. with a desired holding temperature of 50°F; and bin 24 had Pike potatoes grown in St. Joseph Co. with a desired holding temperature of 50°F. Figure 5. Temperature and sugar contents for tuber samples taken during the 1997-1998 storage season. Top two lines are temperatures for the two bins with a range of 40-60°F; middle two lines are sucrose rating (divided by 10 before plotting); bottom two lines are glucose content. Bins 23 and 24 had Snowden potatoes; bins 21 and 22 had selected numbered varieties. Round 5: 1999-20?? Michigan Potato Industry Storage & Handling Committee Objective: investigate management strategies, technologies and varieties to help Michigan growers reduce risk during extended season storage of chip potatoes. Chip Potato Extended Season Storage • • • Varieties - cold chipping for minimal low temperature response (long-term) Storage Control - temperature, humidity, oxygen Storage Management - temperature control relative to potato needs and weather conditions Methods The Michigan potato industry, through the Michigan Potato Industry Commission, purchased land adjacent to the Montcalm potato research farm in the spring of 1999 and constructed on that land an experimental storage building containing six research bins. The bins are 10' x’ 12' by 18' high, holding an estimated 500 cwt. of potatoes. Each bin has an independent air control and management system similar to the previous research bins. The building was finished in the fall of 1999 and filled with Snowden variety potatoes. The storage management protocol for the bins are as follows: Bin 1: potatoes planted June 5 and harvested October 18; desired holding temperature 46°F; comparison with bins 5 and 6 for different planting dates; potatoes were purchased from Sandyland Farms Bin 2: potatoes planted May 23 and harvested October 5; desired holding temperature 46°F; comparison with bins 3 and 4 for different storage temperatures; potatoes were purchased from V&G Farms Bin 3: potatoes planted May 23 and harvested October 5; desired holding temperature 38°F; comparison with bins 2 and 4 for different storage temperatures; potatoes were purchased from V&G Farms Bin 4: potatoes planted May 23 and harvested October 5; desired holding temperature 42°F; comparison with bins 2 and 3 for different storage temperatures; potatoes were purchased from V&G Farms Bin 5: potatoes planted May 15 and harvested September 25; desired holding temperature 46°F; comparison with bins 1 and 6 for different planting dates; potatoes were purchased from Sandyland Farms Bin 6: potatoes planted May 4 and harvested September 18; desired holding temperature 46°F; comparison with bins 5 and 6 for different planting dates; potatoes were purchased from Sandyland Farms The bins are being actively managed by the storage & handling committee relative to sugar contents of the bi-weekly tuber samples from each bin. Sprout inhibitor was applied to all bins on December 29, 1999.