Progress 06/01/06 to 05/31/08
Outputs
OUTPUTS: Fourteen replicated trials on peppers, pickling cucumbers, and squash examined the efficacy of 160 different chemical treatments for the control of Phytophthora capsici. Thirteen studies were conducted on grower cooperator fields serving as both research and demonstration plots. Field experiments used pickling cucumber and pear baits to detect P. capsici in irrigation water sources in two vegetable growing regions of the state. Laboratory experiments were undertaken to investigate the effects of water temperature and zoospore concentration on infection of cucumber fruits. Collaborative laboratory studies with coworkers at Cornell used direct microscopic observation of sporangia to determine if wind dispersal is an important mechanism of spread for P. capsici. Additional greenhouse studies examined the tolerance or susceptibility of 27 commercial and experimental pepper cultivars to several isolates of P. capsici. Large scale on-farm experiments and demonstration trials were conducted in Oceana County to test biofumigant cover crops on P. capsici incidence in vine crops. Greenhouse and two field studies confirmed that Fraser fir seedlings are a new crop that is susceptible to P. capsici. Fruit age susceptibility trials were performed on eight different cucurbit crops harvested at a range of fruit development. For each crop, fruits were harvested on 2 or 3 dates; a total of 50 to 100 fruits were tested for each crop. Experiments were conducted to assess temporal germination dynamics, and the effect of nutritional status and exogenous temperature on sporangial germination behavior. Collaborative studies with coworkers at Cornell University investigated P. capsici disease development in pickling cucumber using staining procedures and light microscopy in conjunction with scanning electron microscopy. DNA was collected from 45 different isolates of P. capsici and 7 genetic markers were sequenced to identify which markers may be most informative when building soil clone libraries for assessing the soil reservoir population of P. capsici in Michigan. Information from plot work and laboratory studies was shared with stakeholders at the 2006 and 2007 Great Lakes Fruit, Vegetable and Farm Market Expo educational sessions, the 21st Annual Southeast Vegetable and Fruit Expo, the 2006 Oceana County Vegetable tour, and the 2007 Michigan State University Phytophthora and Downy Mildew Workshop. Information was also presented to EPA members during a 2007 Decision Makers Field Tour in August and to other researchers at the International Phytophthora capsici Meeting in November of 2007. Economic impact data was collected from a stakeholder survey that was administered to 73 individuals during the 2007 Michigan State University Phytophthora and Downy Mildew Workshop. Additional information on current research, meetings, recent publications, and disease fact sheets has been made available on the project website (http://plantpathology.msu.edu/labs/hausbeck/Phytophthora/Phytophthor ahome.htm). PARTICIPANTS: Dr. Mary Hausbeck, Michigan State University, was the Principal Investigator/Project Director and oversaw the entire Phytophthora project objectives, activities, and reporting to USDA. Dr. Mathieu Ngouajio, Michigan State University, was responsible for the biofumigant research component and Dr. Rebecca Grumet conducted the fruit age susceptibility research at Michigan State University. Dr. Darryl Warncke conducted the soil fertility component of the research at Michigan State University. Dr. Sofia Windstam (post-doc) provided supervised support of graduate students and conducted advanced research experiments in collaboration with Cornell University. Dr. Amanda Gevens (post-doc) supervised research in water management. Kyle Cervantes, Brian Cortright, James Counts, Jr., Tim Cunningham, Sheila Linderman and Bryan Webster, Research Assistants, were responsible for trial design, establishment of plots, oversight and maintenance of plots, harvest/data collection, statistical analyses, and aid in reporting and presentations. Graduate students, Kaori Ando, Leah Granke, Lina Quesada, and Patrick Ogutu, conducted laboratory, greenhouse, and field experiments on various crops and provided assistance with laboratory P. capsici research. Undergraduate students and labor employees were trained as field, greenhouse and laboratory support crew to assist with graduate research projects and also provided direct support for the Research Assistants over the course of this project. These included undergraduate students (Adam Bigham, Priscilla Clark, Adam Cortright, Aristarque Djoko, Jacob Gonzalez, Marc Hasenick, Kyle Heslip, Victor Kayster, Amanda Krato, Pamela Nichols, Justin Passmore, Krystal Richardson, Nick Sears, Alicia Selden, Rebekah Struck, Andrew Worth) and labor employees (Alex Cook, Joey Cooper, Jacob Eagen, Randle Finch, Garrett Freville, Halli Gutting, Lisa Henderson, Patrick Mussell, Holly Rogers, Dan Tratt). Partner organizations for this project included the Pickle Seed Research Fund, Pickle Packers International Inc. and the Pickle and Pepper Research Committee of MSU, Pickle Packers International Inc.; the Michigan Vegetable Council; and the Syngenta, DuPont, Valent, Dow and Bayer chemical companies. Collaborative studies with spore dispersal and germination and microscopy were conducted with researchers at Cornell University. Several commercial seed and chemical companies have provided financial or product support of chemical and variety screens. TARGET AUDIENCES: Research results were presented in 40 talks at local, regional, national and international extension meetings, industry meetings and national scientific meetings attended by growers, packers, processors, industry stakeholders, extension personnel, and other researchers. Regional, national and international extension meetings included the Great Lakes Fruit, Vegetable and Farm Market Expo, Ohio Fruit and Vegetable Growers Congress, Mid-Atlantic Fruit and Vegetable Convention, New England Vegetable and Berry Conference, Annual Southeast Vegetable and Fruit Expo, and Ontario Fruit and Vegetable Convention. National scientific meetings included the 1st Annual Phytophthora capsici Meeting, Cucurbitaceae 2006, and the IR-4 Phytophthora capsici Workshop. Eight of the presentations were given at the Phytophthora and Downy Mildew Workshops, hosted by Michigan State University. These workshops were attended by 80 in 2006 and 142 in 2007 and targeted growers, packers, processors, industry stakeholders, university research and extension personnel, and others. Research and demonstration plots were established in commercial growers' fields and targeted growers and industry stakeholders. The EPA Decision Makers Tour was held at research plots and presented fumigation and foliar spray trial data targeted for government officials, growers, and industry stakeholders. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Gavel 75WG (mancozeb + zoxamide) and the newly registered Presido 4FL (fluopicolide) have been identified as dual purpose fungicides that are effective against both P. capsici and downy mildew. Michigan growers are now encouraged to use well water for irrigation as part of a disease management program since P. capsici was discovered in surface water irrigation sources as a result of the baiting experiments. Laboratory studies have shown that a high percentage of cucumber fruits can be infected between temperatures of 48 to 89F when a sufficient number of zoospores are present. The commercial bell pepper cultivar Paladin (Rogers Seeds), the experimental bell pepper line PRO3-15x16R-5 (Pepper Research Inc.), and the experimental poblano XPP2548 (Sakata Seeds) were the only lines screened that were tolerant to root and crown rot infections when inoculated with a highly virulent isolate of P. capsici. All P. capsici isolates tested on Fraser fir incited disease in the seedlings regardless of incubation temperature or inoculation method. This study suggested that planting Fraser fir in fields infested with P. capsici could result in infection and that adjustments in current crop rotational schemes are needed. The cucurbit fruit-age studies determined that a reduction in susceptibility can be correlated with increasing age/size of cucurbit fruits. The effect was most dramatic in cucumber, as near complete resistance occurred when the fruit reached maturity. Melon, summer squash, and zucchini were the most susceptible to fruit infection caused by P. capsici. The use of biofumigant cover crops did not have a negative effect on disease incidence and can be safely used in a crop management program with susceptible crops. Laboratory experiments have demonstrated that direct sporangial germination is apparent within 1 hour of submerging sporangia in cucumber extract and the germination response is maximized by 3 to 4 hours, when approximately 80% or more of the sporangia have germinated. Direct germination takes place in cucumber extract at temperatures as low as 50F with an optimum around 73F. Germination decreases somewhat at higher temperatures (86F) but not significantly from the optimum. This suggested that if conditions for sporangial dispersal and germination are favorable, temperature rarely becomes a limiting factor for P. capsici infection. Scanning electron microscopy studies of zoospore-inoculated pickling cucumber fruits showed that zoospores very rapidly encysted and attached to the fruit surface (within 10 minutes after inoculation) and germinated 1 hour after inoculation. Time-lapse photography revealed that sporangia can form in as little as 90 minutes on an infected cucumber fruit surface. The stakeholder survey results represented 80,000 total acres with 31% of that acreage having some sort of P. capsici problem. Twenty of the survey participants reported an average loss of $61,409 per farm as a result of P. capsici.
Publications
- Gevens, A.J., Hausbeck, M.K., and Cortright, B.D. 2007. Downy mildew, Phytophthora continue to threaten vine crops. The Vegetable Grower News 41:46-48.
- Gevens, A.J., Hausbeck, M.K., and Cortright, B.D. 2006. Downy mildew and Phytophthora in vine crops. Proc. Great Lakes Fruit, Vegetable and Farm Market Expo, Vine Crops Session Summaries, pp. 16-17. Online.
- Grumet, R, and Ando, K. 2007. Breeding for resistance to downy mildew and Phytophthora rots in cucumber. Proc. Great Lakes Fruit, Vegetable and Farm Market Expo, Pickling Cucumber Session Summaries, pp. 7-10. Online.
- Hausbeck, M. 2007. Controlling Phytophthora disease on pepper. Mich. State Univ. Ext. Vegetable CAT Alert 22(14):2-3 (Aug 1). Online.
- Hausbeck, M. 2007. Phytophthora and fumigation. Mich. State Univ. Ext. Vegetable CAT Alert 22(16):3-4 (Aug 15). Online.
- Hausbeck, M. 2007. Phytophthora and irrigation water. Mich. State Univ. Ext. Vegetable CAT Alert 22(14)2-3 (Aug 8). Online.
- Gevens, A.J., Lamour, K.H., Donahoo, R., and Hausbeck, M.K. 2008. Characterization of Phytophthora capsici causing foliar and pod blight of snap bean in Michigan. Plant Dis. 92:201-209.
- Hausbeck, M.K. 2007. Phytophthora capsici - What you need to know about its biology and management. Proc. New England Vegetable and Fruit Conference, Cucurbits. Online.
- Hausbeck, M.K., Foster, J.M., and Cortright, B. 2007. Phytophthora and downy mildew update. Proc. Great Lakes Fruit, Vegetable and Farm Market Expo, Vine Crops Session Summaries, pp. 9-12. Online.
- Hausbeck, M.K. 2006. Phytophthora research update in peppers. Proc. Great Lakes Fruit, Vegetable and Farm Market Expo, Pepper Session Summaries, pp. 9-11. Online.
- Hausbeck, M. 2006. Phytophthora in pepper production: How to minimize the losses. Mich. State Univ. Ext. Vegetable CAT Alert 21(13):2-3 (Jul 19). Online.
- Ngouajio M., Hausbeck, M.K., and Counts J.W. Jr. 2008. Effects of biofumigants on pickling cucumber and summer squash production in a site infested with Phytophthora capsici. Abstr. HortScience 43:1065-1066.
- Ngouajio, M. 2007. Brassica cover crops can help vegetable systems. The Vegetable Grower News 41(12):10-11.
- Quesada-Ocampo, L.M., Fulbright, D.W., and Hausbeck, M.K. 2007. Susceptibility of Fraser fir to Phytophthora capsici. Abstr. Phytopathology 97:S95.
- Ando, K., and Grumet, R. 2008. Initiation of genomic analysis of cucumber fruit development and relationship to susceptibility to infection by Phytophthora capsici. Abstr. Plant and Animal Genome XVI, p. 278.
- Ando, K., and Grumet, R. 2007. Effect of fruit development on susceptibility of diverse cucurbits to infection by Phytophthora capsici. Abstr. HortScience 42:873.
- Ando, K., and Grumet, R. 2006. Evaluation of altered cucumber plant architecture as a means to reduce Phytophthora capsici disease incidence on cucumber fruit. J. Amer. Soc. Hort. Sci. 131:491-498.
- Ando, K., and Grumet, R. 2006. Factors influencing cucumber fruit susceptibility to infection by Phytophthora capsici. Pages 387-394 in: Proc. Cucurbitaceae 2006. G.J. Holmes, ed. Universal Press, Raleigh, NC.
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Progress 06/01/06 to 05/31/07
Outputs
P. capsici was recovered from 5 MI surface water sites (mid-Jun to mid-Aug 2006): 3 on a southwest river system, a naturally-fed pond in the northwest, and for the 1st time in the Pentwater River (a major waterway used heavily for irrigation in the northwest vegetable growing region). P. capsici appears not to overwinter in water sources; it was last detected on 6 Sep 2005 and first detected on 14 Jun 2006. Cucumber fruits (21 cultivars, 10 plant introductions) were screened for disease resistance; cultivars Sassy, Feisty, Cross Country, Classy F1, Vlaspik, and Moxie had reduced spore production, confirming results from 1999-2005. A trial tested 11 pepper cultivars and breeding lines for disease resistance by planting them in an infested field. Drought prevented disease, but an important horticultural characteristic was evaluated. Cultivar Alliance (P. capsici-tolerant) was least affected by silvering (fruit defect), while Red Knight fruits were unmarketable. Cucurbit
fruits were tested for age-related loss in susceptibility to P. capsici. All crops had some loss in susceptibility; cucumber was most dramatic, while zucchini, melon, watermelon, pumpkin, butternut and acorn squashes showed reduced susceptibility with age. Yellow summer squash was the most susceptible at all ages. The effects of Brassica (brown, oriental mustards) and oilseed radish cover crops, and raised versus flat planting beds on P. capsici of pickling cucumber and yellow squash were tested in experiments on a commercial farm. Beneficial effects of the cover crops were more evident in the flat bed compared with the raised bed system, but due to severe disease pressure they were not high enough for the cover crops to be used as stand-alone tools. Fraser fir was first reported to be a host to P. capsici in 2006. Products (25, including 3 biopesticides, 3 reduced-risk and 5 experimental fungicides) were tested alone and in combination (88 treatments) in 6 field trials during 2006
for management of P. capsici. V-10161 4FL (fluopicolide) limited acorn squash plant death to 28.9% compared to the untreated (62.5% death), and produced 8.3% diseased cucumber fruit compared to the untreated (22.5%) in spray trials. V-10161 4FL also limited plant death when applied through drip irrigation. V-10162 5.73FL (fluopicolide + propamocarb) significantly decreased pepper plant death by 65% and increased yield by 75% when applied as a drench at transplant and as a weekly foliar spray compared to the untreated. Phytophthora Fact Sheets were developed and distributed to growers at the Oceana Co. Vegetable Tour (24 Jul 2006), the P. capsici Workshop, and are available online at the project website. The P. capsici Workshop (E. Lansing, 24 Jan 2007) featured a "hands-on" laboratory and educators from Michigan State, North Carolina State and Purdue Universities. Research results were presented at Cucurbitaceae 2006 (Asheville, NC, 17-21 Sep 2006), the Vine Crops Session of the Great
Lakes Fruit, Vegetable and Farm Market Expo (Grand Rapids, 6 Dec 2006, 254 attendees) and at the Cucumber Reporting Session (E. Lansing, 11 Jan 2007, attendees represent 95% of processing cucumber acreage).
Impacts
MI produced 12 P. capsici-susceptible crops valued at $132 million on 62,260 acres in 2006. MI ranks in the top 11 states for production of 8 of these crops, including 1st for pickle, 2nd for squash, and 4th for fresh market cucumber, processing snap bean, processing tomato. Finding P. capsici in MI agricultural water impacted nearly 4,000 acres of vegetables. In response, 6 wells have been drilled for uncontaminated irrigation water. For crops with age-associated increase in resistance, fungicide protection will be most critical at the early stages of fruit development. Fraser fir was found to be a host to P. capsici. P. capsici is a threat to the MI's Christmas tree industry, as Fraser firs comprised 25.5% (crop value, $10.6 million) of Christmas tree sales (grown on 7,600 acres) in 2004. Where vegetable and Christmas tree production occur in the same regions, growers will need to be especially aware of this pathogen's ability to infect vegetables and Fraser fir, and
of the unsuitability of Fraser firs as a rotation crop. Positive effects of cover crops on P. capsici management were limited in magnitude, suggesting that they should be combined with other management tools. The Phytophthora Workshop was attended by 142 growers, industry and extension personnel and researchers from MI, 7 other states and Canada. Previous attendance of this workshop was 40-50 people. MI growers are aware that Phytophthora management is critical to the future of MI's vegetable industry; they are actively seeking management options to control this devastating disease.
Publications
- Gevens, A.J., Lamour, K.H., Donahoo, R., Hausbeck, M.K. 2007. Characterization of Phytophthora capsici from Michigan surface irrigation water. Phytopathology 97:421-428.
- Hausbeck, M.K., Cortright, B.D. 2007. Evaluation of fungicides and applications for management of Phytophthora blight of pepper, 2006. Plant Disease Management Reports 1:V139.
- Gevens, A.J., Ando, K., Lamour, K.H., Grumet, R., Hausbeck, M.K. 2006. A detached cucumber fruit method to screen for resistance to Phytophthora capsici and effect of fruit age on susceptibility to infection. Plant Dis. 90:1276-1282.
- Hausbeck, M.K., Gevens, A.J., Cortright, B. 2006. Integrating cultural and chemical strategies to control Phytophthora capsici and limit its spread. Pp. 427-435 in: Proc. of Cucurbitaceae 2006. G.J. Holmes, ed. Universal Press, Raleigh, NC.
- Gevens, A.J., Donahoo, R.S., Lamour, K.H., Hausbeck, M.K. 2006. Identification and characterization of Phytophthora capsici on bean in Michigan. Abstr. Phytopathology 96:S39.
- Ando, K., Grumet, R., Terpstra, K., Kelly, J.D. 2007. Manipulation of plant architecture to enhance crop disease control. CAB Reviews: Perspectives in Agriculture, Veterinary Medicine, Nutrition and Natural Resources 2, No. 26. 8 pp.
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