TO DEVELOP EFFECTIVE STRATEGIES FOR MANAGEMENT OF PHYTOPHTHORA BLIGHT OF PUMPKINS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0202621
• Project Start Date: Oct 1, 2004
• Project End Date: Sep 30, 2010
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF ILLINOIS
2001 S. Lincoln Ave.
URBANA,IL 61801

Performing Department
CROP SCIENCES

Non Technical Summary
Phytophthora blight is the most serious disease of cucurbits and peppers. The pathogen infects more than 40 crop and weed species. This project will examine effective tactics for controlling Phytophthora blight of pumpkins and develop effective strategies for control of this disease.

Animal Health Component

50%

Research Effort Categories

Basic

40%

Applied

50%

Developmental

10%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	1429	1160	60%
212	1429	1170	40%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants;

Subject Of Investigation
1429 - Cucurbits, other;

Field Of Science
1160 - Pathology; 1170 - Epidemiology;

Keywords

vegetables

pumpkins

plant diseases

phytophthora capsici

plant disease control

disease management

integrated pest management

genetic diversity

rapd

seed treatment

plant disease resistance

cucurbita

food processing

fungus diseases (plants)

blight

survival

fungicides

epidemiology

soil borne diseases

disease detection

fungus genetics

Goals / Objectives
The main objective of this project is to develop effective strategies for management of Phytophthora blight of pumpkins, caused by Phytophthora capsici. The specific objectives of the research are: (i) detect and quantify P. capsici in soil; (ii) to determine survival of P. capsici in soil; (iii) to determine genotypic and pathogenic diversity among P. capsici isolates from pumpkin fields; and (iv) to determine the effectiveness of integrated approaches of using induced plant-resistance, seed-treatment, and fungicide spray on controlling P. capsici. Phytophthora blight is a devastating disease of cucurbits (particularly pumpkins) and peppers. Also, P. capsici infects more than 40 other crop and weed species. P. capsici is a soilborne and airborne pathogen. It may survive in soil indefinitely. P. capsici can strike host plants at any time from planting through harvest, causing seedling death, foliage blight, and fruit rot. The disease develops and spreads rapidly. At present, there is no single method to provide adequate control of P. capsici on pumpkins and other crops. No cucurbit cultivar with measurable resistance is available. Other disease management practices, including amending the soil, using cover crops, straw mulching, and using antagonistic fungi, have not provided adequate protection in cucurbits against P. capsici. The efficacy of fungicides in protecting the crops against P. capsici varies from one area to another. Among more than 40 fungicides that were tested on pumpkins in Illinois, only dimethomorph (Acrobat) provided an acceptable protection to cucurbit crops against P. capsici. Methyl bromide, a soil fumigant, has also been used to control soil-borne P. capsici. The use of methyl bromide, however, does not provide protection against air-borne inoculum of P. capsici, is often uneconomical, and it is in the phase-out transition and will not be available after 2005. Illinois has approximately 22,000 acres of pumpkins and ranks first in pumpkin production. About 90% of the commercial processing pumpkins in the United States are produced in Illinois. Also, approximately 10,000 acres of commercial farms in Illinois are planted to cucumbers, gourds, melons, squash, eggplants, peppers, and tomatoes. Yield losses up to 100% in pumpkin, other cucurbit crops, and pepper fields have been recorded in Illinois. Outcomes of this project will be to: (i) introduce new techniques for studying biology of P. capsici; (ii) manage Phytophthora blight of vegetables; (iii) enhance grower's knowledge on using integrated pest management (IMP); (iv) help to sustain production of the pumpkin crop, the most valuable vegetable crop in Illinois; (v) improving growers income; (vi) adapt new strategies for controlling Phytophthora diseases in other crops; (vii) ensure that vegetable production will be an important component of state economy; and (viii) secure safe maintenance of vegetable farms to fulfill social needs of the communities, as these farms provide various educational and recreational programs to students, tourists, and residents of the communities.

Project Methods
A reliable wet sieving procedure to separate and quantify P. capsici oospores from soil will be developed. To develop this method, oospores will be incorporated into a pasteurized soil mix (sand:soil; 1:1) at density of 10, 1,000, 100, 10,000, and 100,000 oospores per gram of dry soil. Then, a 10 g soil sample will be suspended in 100 ml water and the suspension will be passed through 117, 57, and 20 micron sieves. Oospores will be collected and centrifuged (3 minutes at 1,200 g). Then the pellet will be suspended in 1 M sucrose solution and the suspension will be centrifuged at different g for different periods of time to determine the optimum centrifugation time for maximum oospore recovery from soil. The data will be analyzed and a model will be developed to estimate actual number of oospores in soil. To determine survival of the pathogen in soil, oospores of P. capsici will be incorporated into different soil types, placed into appropriate plastic mesh, buried in different depths (2, 10, and 25 cm) in the ground, sampled periodically (up to 5 years), and oospores will be extracted and tested for germination. Based on survival of oospores of P. capsici in soil, effective crop rotation periods for managing Phytophthora blight in commercial fields will be determined. To determine genetic and pathogenic variation in the pathogen, isolates of P. capsici from pumpkin fields in different locations in Illinois will be collected and studied. Random amplified polymorphic DNA (RAPD) markers will be employed to assess genetic variation among at least 20 isolates of P. capsici from pumpkin fields. Other molecular methods may also be used for determining genetic variation among the isolates. Pumpkin seedlings will be grown in a glasshouse and inoculated with the isolates to determine their virulence. Integrated approaches using induced plant resistance, fungicide seed treatment, and spray-applications of fungicides will be tested to develop effective strategies for control of Phytophthora blight in pumpkin fields. Seed treatment with mefenoxam or metalaxyl will be included in the integrated disease management strategies. Fungicides with potential effectiveness on controlling Phytophthora diseases (i.e., dimethomorph [Acrobat 50WP], cymoxanil [Curzate 60DF]) will be evaluated for their effectiveness on controlling P. capsici on pumpkins. Spray-applications of the effective fungicides will be further evaluated in integrated approaches with other above-mentioned control tactics. The research will be conducted in the vegetable pathology laboratory in the Department of Crop Sciences at the University of Illinois at Urbana-Champaign (UIUC), plant care facilities of the Department of Crop Sciences and the College of Agricultural, Consumer and Environmental Sciences (ACES) of UIUC, and commercial fields at Champaign, Pekin, and Shawneetown, Illinois. The vegetable pathology laboratory has enough facilities for carrying out this research study. Plant care facilities of ACES have excellent facilities to conduct glasshouse studies. Necessary commercial field areas will be provided by the growers and processing pumpkin companies to conduct field trials.

Progress 10/01/04 to 09/30/10

Outputs
OUTPUTS: Illinois ranks first in pumpkin production among all states in the nation. More than 90% of processing pumpkins produced in the United States are grown and processed in Illinois. Phytophthora blight, caused by Phytophthora capsici, is the most serious threat to production of pumpkins. The objectives of this research were: 1) to detect and quantify P. capsici in soil; 2) to determine survival of P. capsici in soil; 3) to determine genotypic and pathogenic diversity among P. capsici isolates from pumpkin fields; and 4) to determine the effectiveness of integrated approaches of red-light treatment, calcium application, seed-treatment, and fungicide spray on controlling P. capsici. For the first objective, a procedure was developed to quantify P. capsici oospores in soil by combining a sieving-centrifugation method and a real-time quantitative polymerase chain reaction (QPCR) assay. The relationship between number of oospores recovered from soil and number of oospores incorporated into the soil was Ŷ = - 0.95 + 1.31X - 0.03X2, where Ŷ = log10 of number of oospores recovered from soil and X = log10 of number of oospores incorporated into soil. The relationship between the DNA quantities of P. capsici oospores recovered form soil and the number of oospores incorporated into the soil was Ŷ = - 3.53 - 0.73X + 0.32X2, where Ŷ = log10(DNA quantity of P. capsici oospores recovered from soil) and X = log10(number of P. capsici oospores incorporated into soil). For the second objective, four soil textures with 5,000 oospores per gram dry soil were used. The infested soil samples in mesh polyester bags were placed at 2, 10, and 25 cm deep in a field. Soil samples were assayed for recovery and germination of the oospores after 1 day and 3, 6, 12, 24, 30, 36, and 48 months. Oospore recovery from soil samples was 60.60, 16.70, 10.10, 0.92, 0.41, 0.06, 0.04, and 0.004% after 1 day and 3, 6, 12, 24, 30, 36, and 48 months from burying samples in soil, respectively. Percentage of oospore germination was 53.20, 47.20, 28.97, 20.82, 15.53, 7.57, 2.74, 2.52, and 0.00 at time zero and after 1 day and 3, 6, 12, 24, 30, 36, and 48 months, respectively. For the third objective, random amplified polymorphic DNA (RAPD) markers were employed to assess genetic variation among 24 isolates of P. capsici from 10 fields. Inoculation of pumpkin seedlings in the greenhouse revealed that the isolates belonging to six distinct genetic groups differing significantly in virulence. For the fourth objective, the following management approach was concluded and recommended to the growers. Phytophthora blight of pumpkin and other cucurbits can be effectively managed by crop rotation for at least 3 years with nonhosts, seed treatments with mefenoxam (Apron XL LS, at 0.64 fl oz/100 lb seed) prior to sowing seed, disking infected plants in localized areas in the field in early season to prevent inoculum build up, and spray-applications of effective fungicides (e.g., dimethomorph, famoxadone + cymoxanil, mandipropamid, cyazofamid, and fluopicolide). Red-light treatment and applications of calcium did not provide season long protection of crops against P. capsici. PARTICIPANTS: M. Babadoost (PI). Research and extension plant pathologist for vegetable crops, Department of Crop Sciences, University of Illinois. Has been working on management of Phytophthora blight and other diseases of vegetables in Illinois for about four years. He will be involved in all aspects of laboratory, greenhouse, and field research. S.Z. Islam. Senior Research Specialist, Department of Crop Sciences, University of Illinois. Is one of the pioneers in inducing plant resistance by red-light treatment. He has been working on management of Phytophthora diseases of vegetables in Illinois for four years. S.Z. Islam will be responsible for conducting laboratory, glasshouse, and filed research. He will also assist the PI in analyzing data and preparing publications. T.P. Laatsch (Collaborator). Agriculture Manager, Nestle Food Company. Has more than 20 years of experience on production of processing pumpkin. He will collaborate in conducting the trials and provide facilities for field trials at Pekin, Illinois as needed. Part-time students employed to assist the PI and the research specialist to carry out the study. Institutions involved: Department of Crops Sciences, University of Illinois at Urbana-Champaign. TARGET AUDIENCES: Growers, extension educators, industry personnel, students, and researchers. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Illinois produces approximately 35,000 acres of cucurbit crops (cucumber, cantaloupe, gourd, pumpkin, squash, and watermelon) annually. More than 90% of the processing pumpkins produced in the U.S. are grown and processed in Illinois. Phytophthora blight, caused by Phytophthora capsici, is the most serious threat to production of cucurbits Illinois, as well as nationwide. Surveys conducted in 1999 and 2000 showed up to 100% crop losses in pumpkin fields in Illinois. Research was initiated in 1999 to develop a short-term solution and to establish a long-term strategy to manage Phytophthora blight of vegetables. The initial research focused on processing pumpkin and bell pepper, hosts most susceptible to P. capsici. The objective of this research was to develop effective control for Phytophthora blight and save the highly unique processing pumpkin industry, as well as other cucurbits and peppers. No variety of pumpkin, or other cucurbits, with measurable resistance to P. capsici was found. Intensive research was conducted in the laboratory, greenhouse, and field during 2000-2010 to determine effective fungicides for control of P. capsici. Among more than 50 fungicides with potential effects on Phytophthora, only six of them were found to be effective against foliar blight and fruit rot of cucurbits caused by P. capsici in Illinois. All of these fungicides received registration for use on cucurbits, to a good extent, based on the data generated in Illinois. A significant accomplishment on management of Phytophthora blight of cucurbits was development by seed treatment to control seedling death of plants caused by P. capsici during the early growth stages of the plants. Seed treated with Apron XL LS (mefenoxam), which effectively protects seedlings against P. capsici until about 5 weeks after sowing seeds, was developed and is now widely used. The cost for this seed treatment is less than $0.10 per acre. By combining Apron seed treatment with applications of effective fungicides, yield losses in cucurbit fields were reduced from up to 100% to less than 10%. As a result, acreage of processing pumpkins increased by 133% from 1998 to 2011. Due to the devastating effect of Phytophthora blight on processing pumpkin yields, the processing pumpkin industry in Illinois was at the risk of complete loss in 2000. Developing effective methods for control of the disease saved this high-value industry. Since 2004, the program of my program has focused on developing effective integrated approaches for control of P. capsici. Cropping rotation is a fundamental approach in management of plant diseases. To develop effective cropping rotations, we first studied and determined the host range of P. capsici in Illinois (2004 Plant Disease 88:485-489). Then, we developed reliable methods for assessing survival of P. capsici in the fields (2008 Plant Disease 92:143-149), which enabled us to determine that P. capsici does not survive in the soil in Illinois for more than four years. Thus, we concluded that at least three years of cropping rotation with non-host crops is needed for effective management of P. capsici in vegetable crops.

Publications

• Babadoost, M. 2008. Fungicide evaluation for control of Phytophthora blight and downy mildew of processing pumpkin, 2007. Plant Disease Management Report 2(63): V164.
• Babadoost, M. 2008. Phytophthora capsici: a serious threat to vegetable industries in the world. Phytopathology (supplement), 98 (6): S197.
• Babadoost, M. 2008. Major fruit rots of cucurbits in Illinois. Agronomy Day 2007, The 52st Annual Agronomy Day, Dept. of Crop Sciences, UIUC, The Crop Science Research and Education Center, Urbana, IL: 28.
• Babadoost, M. and Islam, S.Z. 2009. Fungicides for control of Phytophthora blight (Phytophthora capsici) of pumpkin in Illinois. Proceedings of the 2nd International Phytophthora capsici Conference, Duck Cay, FL, 1-2 December 2009: page 21.
• Thru Ppoyil, S.B., Babadoost, M. and Kushad, M.M. 2009. Effectiveness of Brassica short-cycle cover crops in managing Phytophthora capsici and Fusarium spp. in cucurbit fields. The American Phytopathological Society, North Central Division. Ames, IA, June 21-23, 2009. Abstract.
• Eranthodi, A., Babadoost, M. and Trierweiler, B. 2010. Thermotherapy for control of fungal pathogens in propagative rootstocks of horseradish. HortScience 45 (4): 599-604.
• Babadoost, M. 2010. Evaluation of fungicides for control of Phytophthora blight of processing pumpkin, 2009. Plant Dis. Management Rep. 4 (65):V096.
• Babadoost, M. 2010. Phytophthora blight of cucurbits crop. Illinois Fruit and Vegetable News, Volume 16, Number 6: 55-56.
• Babadoost, M. and Islam, S.Z. 2005. Efficacy of selected fungicides for control of Phytophthora blight (Phytophthora capsici) in processing pumpkin diseases in Illinois in 2005. Pages 36-42 in 9th Annual Illinois Fruit and Vegetable Research Report.
• Babadoost, M. and Islam, S.Z. 2005. Fungicide evaluation for control of Phytophthora blight of processing pumpkin, 2005. Fung. & Nemat. Tests 61: V023.
• Babadoost, M., Swiader, J.S. and Islam, S.Z. 2006. To develop and implement effective tactics for management of Phytophthora blight of vegetables. Pages 2-3. In USDA-CSREES, North Central Region Integrated Pest Management Grants Program.
• Babadoost, M., Islam, S.Z., Pavon, C. and Tian, D. 2006. Strategies for management of Phytophthora blight (Phytophthora capsici) of cucurbits. 5th National Integrated Pest Management Symposium, April 4-6, 2006, St. Louis, Missouri. Abstract of papers: P084, page 83.
• Pavon, C. and Babadoost, M. 2006. Detection and quantification of Phytophthora capsici oospores in soil with real-time quantitative polymerase chain reaction. Phytopathology 96:S91, In the Abstracts of papers of joint meeting of APS, CPS, and MSA. July 29-August 2, 2006, Quebec City, Canada.
• Babadoost, M. 2006. Phytophthora blight of cucurbits. Illinois Fruit and Vegetable News, Volume 12, Number 8: 82.
• Pavon, C. and Babadoost, M. 2006. Determining density of Phytophthora capsici oospores in soil. Pages 507-514 in Proceedings of Cucurbitaceae 2006, September 17-21, 2006, North Carolina State University, Asheville, NC, USA.
• Babadoost, M. and Jurgens, A. 2006. Evaluating efficacy of fungicides for control of Phytophthora blight (Phytophthora capsici) in processing pumpkin in Illinois in 2006. Pages 42-47 in 10th Annual Illinois Fruit and Vegetable Research Report.
• Babadoost, M. 2007. Evaluation of fungicides for control of Phytophthora blight of processing pumpkin, 2006. Plant Disease Management Report 1(62): V029.
• Babadoost, M. 2007. An IPM strategy for managing Phytophthora blight (Phytophthora capsici) in cucurbit fields. HortScience 42: 872.
• Jasinski J., Pilcher, C., Weinzierl. R., Babbadoost, M., Maynard, M., Gunter, C., Breinling, J. Myers, N., Welty, C., LeBoeuf, J. and Roddy, E. 2007. Assessing IPM Adoption of North Central Region Pumpkin Growers. Poster presentation, National Entomological Society, 2007.
• Babadoost, M. 2007. Fruit rots of pumpkin. A CD Video prepared by the Great Lake Vegetable Working Group. Distributed in the U.S. and Canada.
• Pavon, C.F., Babadoost, M. and Lambert, K.N. 2008. Quantification of Phytophthora capsici oospores in soil by sieving-centrifugation and real-time polymerase chain reaction. Plant Dis. 92:143-149.
• Babadoost, M., Tian, D., Islam, S.Z. and Pavon, C. 2008. Challenges and options in managing Phytophthora blight (Phytophthora capsici) of cucurbits. Proceedings of Cucurbitaceae 2008, May 21-24, 2008, Avignon, France: 399-406.
• Babadoost, M. 2008. Phytophthora blight of cucurbits. Illinois Fruit and Vegetable News, Volume 14, Number 7: 60-61.

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: Illinois ranks first in pumpkin production among all states in the nation. More than 90% of processing pumpkins produced in the United States are grown and processed in Illinois. Phytophthora blight, caused by Phytophthora capsici, is the most serious threat to production and the pumpkin industry and other cucurbit crops in Illinois and worldwide. P. capsici survives as oospores (thick-walled spores) in soil and attacks host plants throughout the growing season. The objective of this research is to develop effective strategies for management of Phytophthora blight in pumpkin fields. Results of the research on survival of P. capsici oospores in soil and efficacy of selected fungicides for control of Phytophthora blight are reported here. Four different soil types were autoclaved to eradicate contaminated microorganisms. The autoclaved soil samples were infested with oospores of P. capsici to give a density of 5,000 oospores per gram of dry soil. Aliquots of 18 g of the infested soils were placed in 15-micro meter mesh polyester bags, which were sealed and placed at 2, 10, and 25 cm depths in PVC tubes containing the same field soil as the infested soil. Tubes were buried vertically in the ground of a commercial field at Champaign, IL, in October 2004. Also, mesh bags containing infested soil were placed on the soil surface. Mesh bags were removed and soil samples were assayed for recovery and germination of P. capsici oospores after 3, 6, 12, 18, 24, 30, 36, and 48 months, using the sucrose-centrifugation method developed in our laboratory. Oospore recovery from soil samples inside PVC tubes was 16.7, 10.1, 0.9, 0.4, 0.06, 0.04, and 0.004% after 3, 6, 12, 18, 24, 30, 36, and 48 months, respectively. There were no significant differences in percentage of oospore recovery either among the soil types or among the burial depths. The percentage of oospore germination was 29.0, 13.3, 7.6, 2.7, 2.5, and 0.0% after 3, 12, 18, 24, 30, 36, and 48 months, respectively. After 36 months from incorporating oospores into soil, no oospore was recovered from the bags placed on the soil. In 2009, 14 fungicides, including Aliette, Apron XL LS, BAS65100F, Bravo Weather Stik, Forum, Gavel, Kocide-3000, Presidio, Ranman, Revus, Ridomil Gold SC, Ridomil Gold Copper, Tanos, and an experimental fungicide, in 30 treatments, were evaluated for their efficacy for control of P. capsici on pumpkins. Percentage of vine infection with P. capsici in all treatments, except Ridomil Gold SC treatment only, was significantly lower than that in the untreated check. No vine infection was observed in the plots of two treatments, including the treatment with spray-applications of Tanos plus Activator-90 alternated with Gavel plus Activator-90 and the treatment with a soil application of Ridomil Gold SC and spray-applications of Revus plus Kocide-3000 plus Activator-90 alternated with Ridomil Gold Copper. Percent of fruit infection ranged from 2.70 to 41.05%. The lowest percentage of fruit infection (2.70%) was in the plots received a soil-application of Ridomil Gold SC plus Presidio and spray-applications of Presidio plus Gavel alternated with Tanos plus Bravo Weather Stik. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The pumpkin industry is the most valuable vegetable industry in Illinois. Results of this research are helping the pumpkin industry to continue to be a significant component of the Illinois agricultural economy. Production of pumpkins, particularly production of processing pumpkins, in Illinois is increasing. For example, the acreage of processing pumpkins increased by more than 80% in the past nine years. Due to the market demand and effectively controlling Phytophthora blight, processed pumpkin production is expected to exceed 13,000 acres in 2010 (an increase of about 20% over the 2009 production).

Publications

• Babadoost, M. and Jurgens, A. 2009. Evaluation of an experimental fungicide for control of Phytophthora Blight (Phytophthora capsici) in processing pumpkin in Illinois, 2008. 12th Annual Illinois Fruit and Vegetable Research Reports: 57-60.
• Babadoost, M. and Jurgens, A. 2008. Efficacy of selected fungicides for control of Phytophthora blight (Phytophthora capsici) in processing pumpkin in Illinois, 2008. 12th Annual Illinois Fruit and Vegetable Research Reports: 61-65.
• Babadoost, M. and Zitter, T.A. 2008. Fruit rots of pumpkin: A serious threat to the pumpkin industry. Plant Disease 93: 772-782.
• Babadoost, M. and Islam, S. 2009. Fungicides for control of Phytophthora blight (Phytophthora capsici) of pumpkin in Illinois. Proceedings of the 2nd International Phytophthora capsici Conference, Duck Cay, FL, 1-2 December 2009: page 21.
• Babadoost, M. 2009. Management of diseases in pumpkin fields. Pumpkin Workshop, Illinois Specialty Growers Meeting. Springfield, IL, 7 January 2009.
• Babadoost, M. 2009. Cucurbit diseases. Southern Illinois Commercial Vegetable School. Mt. Vernon, IL, 11 February 2009.
• Babadoost, M. 2009. Chemical control of Phytophthora blight (Phytophthora capsici) of pumpkin in Illinois. Phytopathology 99: S6.
• Babadoost, M. 2009. Cucurbit and tomato diseases. Illinois Fruit and Vegetable News, Volume 15, Number 11: 107-110.
• Babadoost, M. 2009. Integrated approaches for management of Phytophthora blight (Phytophthora capsici) of cucurbits. The 4th International Cucurbitaceae Symposium, Changsha, Hunan, China, 21-24 September 2009. The Abstracts of Papers, Abstract OS4-5 (pages 36-37).
• Babadoost, M. and Pavon, C. 2009. Survival of Phytophthora capsici oospores in soil. Proceedings of the 2nd International Phytophthora capsici Conference, Duck Cay, FL, 1-2 December 2009: page 11.
• Babadoost, M. 2009. Updates on tomato and cucurbit diseases. Stateline (IL-WI) Illinois-Wisconsin Fruit and Vegetable Growers Meetings. Harvard, IL, 16 February 2009.
• Babadoost, M. 2009. Management of pumpkin diseases. Western Illinois and Eastern Iowa Growers Meeting. Quincy, IL, 17 February 2009.
• Babadoost, M. 2009. Vegetable diseases updates. Northeast Illinois Vegetable Growers Meeting. Kankakee, IL, 18 February 2009.
• Babadoost, M. 2009. Pumpkin diseases. Illinois pumpkin field day (a multi-sate field meeting). Champaign, IL, 10 September 2009.
• Babadoost, M. 2009. Pumpkin and Phytophthora blight. A presentation in the Department of Crop Sciences, University of Illinois, Urbana-Champaign, 4 September 2009.

Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: Illinois, with annual production of approximately 20,000 acres of pumpkins, ranks first in pumpkin production among the states in the nation. More than 90% of processing pumpkins produced in the U.S. are grown and processed in Illinois. Phytophthora blight, caused by Phytophthora capsici, is the most serious threat to production and the industries of pumpkins and other cucurbit crops (cucumbers, gourds, melons, squashes) in Illinois and worldwide. P. capsici survives as oospores (thick-walled spores) in soil for more than three years and attack host plants throughout the growing season. No single method provides adequate control of P. capsici on pumpkins and other crops. There is no measurable resistance in pumpkin or other cucurbit cultivars against P. capsici. The objective of this research is to develop effective strategies for management of Phytophthora blight in pumpkin fields. This is a report on the results of the studies on survival of P. capsici oospores in soil and effectiveness of new fungicides for control of Phytophthora blight. Four soil types, including one clay loam, one silt clay loam, and two silt loams, were autoclaved to eradicate contaminated microorganisms. The autoclaved soil samples were infested with oospores of P. capsici to give a density of 5,000 oospores per gram of dry soil. Aliquots of 18 grams of the infested soils were placed in 15-miro meter mesh polyester bags, which were sealed and placed at 2, 10, and 25 cm depths in PVC tubes containing the same field soil as the infested bags. Tubes were buried vertically in the ground of a commercial field in Champaign, Illinois, in October of 2004. Soil samples were assayed for recovery and germination of P. capsici oospores after 3, 6, 12, 18, 24, 30, 36, and 48 months from incorporating the spores into soil, using the sucrose-centrifugation method developed in our laboratory. Oospore recovery from soil samples was 16.7, 10.1, 0.9, 0.4, 0.06, and 0.04% after 3, 6, 12, 18, 24, 30, and 36 months from incorporation of spores into soil, respectively. Soil samples recovered after 48 moths from incorporation of spores in soils are being processed and the results will be reported later. There were no significant differences in percentage of oospore recovery either among the soil types or among the burial depths. The percentage of oospore germination was 29.0, 13.3, 7.6, 2.7, and 2.5% after 3, 12, 18, 24, 30, and 36 months from incorporation of the spores into soil, respectively. In 2008, 13 fungicides, Apron XL LS, Bravo Weather Stik 6F, Cuprofix Ultra 40DF, Forum 4.16SC, Gavel 75DF, Kocide-3000 46.1DF, Previcur Flex 6F, Presidio 4SC, Ranman 400F, Revus 2.09SC, Ridomil Gold 480SL, Ridomil Gold Copper 65WP, and Tanos 50DWG, with potential of controlling Phytophthora pathogens were evaluated for their efficacy for control of P. capsici on pumpkins. Fungicides BAS 65100F (a new fungicide), Revus (mandipropamid), fluopicolide (Presidio 4SC), Forum (dimethomorph), Tanos (famoxadone + cymoxanil), Ranman (cyazofamid), and Zaxomide (Gavel 75DF) were effective for control of P. capsici on pumpkin in Illinois. PARTICIPANTS: The field trials were visited by the growers and extension personnel. The results of this study are presented to the growers, extension educators, agribusiness personnel, and scientists in various local, regional, national, and international meetings. TARGET AUDIENCES: Vegetable growers, extension educators/specialists, agribusiness personnel, and scientists. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The pumpkin industry is the most valuable vegetable industry in Illinois. Results of this research will help to assure that the pumpkin industry will continue to be a significant component of the Illinois agricultural economy.

Publications

• Babadoost, M. 2008. Phytophthora blight of cucurbits. Illinois Fruit and Vegetable News, Volume 14, Number 7: 60-61.
• Babadoost, M. 2008. Fungicide evaluation for control of Phytophthora blight and downy mildew of processing pumpkin, 2007. Plant Disease Management Report 2(63): V164.
• Babadoost, M. 2008. Phytophthora capsici: A serious threat to vegetable industries in the world. Phytopathology (supplement), 98 (6): S197.
• Babadoost, M. 2008. Major fruit rots of cucurbits in Illinois. Agronomy Day 2007, The 52st Annual Agronomy Day, Dept. of Crop Sciences, UIUC, The Crop Science Research and Education Center, Urbana, IL: 28.
• Babadoost, M. and Zitter, T.A. 2008. The fruit rots of pumpkin: a serious threat to pumpkin industry. Plant Disease 92 (Under Review).
• Babadoost, M. Fruit rots of pumpkin. 2007. A CD Video prepared by the Great Lake Vegetable Working Group. Distributed in the US and Canada.
• Babadoost, M., Tian, D., Islam, S.Z., and Pavon, C. 2008. Challenges and options in managing Phytophthora blight (Phytophthora capsici) of cucurbits. Proceedings of Cucurbitaceae 2008, May 21-24, 2008, Avignon, France: 399-406.

Progress 01/01/07 to 12/31/07

Outputs
Illinois, with annual production of approximately 20,000 acres of pumpkins, ranks first in pumpkin production in the nation. More than 90% of processing pumpkins produced in the U.S. are grown and processed in Illinois. Phytophthora blight, caused by Phytophthora capsici, is the most serious threat to production and industry of pumpkins and other cucurbit crops (cucumbers, gourds, melons, squashes) in Illinois and worldwide. Crop losses of up to 100% in pumpkin and other cucurbit fields have been recorded in various parts of Illinois. This pathogen survives as oospores (thick-walled spores) in soil for more than three years and attack host plant throughout the growing season. At present, there is no single method to provide adequate control of P. capsici on pumpkins and other crops. There is no measurable resistance in pumpkin or other cucurbit cultivars against P. capsici. The objective of this research is to develop effective strategies for management of Phytophthora blight in pumpkin fields. This report is the result of the studies on survival of P. capsici oospores in soil and effective fungicides for control of Phytophthora blight. Four soil types, including one clay loam, one silt clay loam, and two silt loams, collected from commercial fields in Champaign (east central), Collinsville (southwest), Pekin (north central), and Shawneetown (southeast), Illinois, were autoclaved to eradicate contaminated microorganisms. The autoclaved soil samples were infested with oospores of P. capsici to give a density of 5,000 oospores per gram of dry soil. Aliquots of 18 g of the infested soils were placed in 15-micro meter mesh polyester bags, which were sealed and placed at 2, 10, and 25 cm depths in PVC tubes containing the same field soil as the infested bags. Tubes were buried vertically in the ground of a commercial field in Champaign, IL, in October 2004. Soil samples were assayed for recovery and germination of P. capsici oospores after 3, 6, 12, 18, 24, 30, and 36 months from incorporating the spores into soil, using the sucrose-centrifugation method developed in our laboratory. Oospore recovery from soil samples was 16.7, 10.1, 0.9, 0.4, 0.06, and 0.04% after 3, 6, 12, 18, 24, 30, and 36 months from incorporation of spores into soil, respectively. There were no significant differences in percentage of oospore recovery either among the soil types or among the burial depths. The percentage of oospore germination was 29.0, 13.3, 7.6, 2.7, and 2.5% after 3, 12, 18, 24, 30, and 36 months from incorporation of the spores into soil, respectively. More than 50 fungicides with potential of controlling Phytophthora pathogens were evaluated for their efficacy for control of P. capsici on pumpkins. The most effective fungicides for control of P. capsici in Illinois were dimethomorph (Acrobat, Forum), famoxadone + cymoxanil (Tanos), cyazofamid (Ranman), mandipropamid (Revus), and captan.

Impacts
The pumpkin industry is the most valuable vegetable industry in Illinois. Results of this research will help to assure that pumpkin industry will continue to be a significant component of Illinois' agricultural economy.

Publications

• Babadoost, M. and Jurgens, A. 2006. Evaluating efficacy of fungicides for control of Phytophthora blight (Phytophthora capsici) in processing pumpkin in Illinois in 2006. Pages 42-47 in 10th Annual Illinois Fruit and Vegetable Research Report.
• Babadoost, M. 2007. Evaluation of fungicides for control of Phytophthora blight of processing pumpkin, 2006. Plant Disease Management Report 1(62): V029.
• Babadoost, M. 2007. An IPM strategy for managing Phytophthora blight (Phytophthora capsici) in cucurbit fields. HortScience 42: 872.
• Babadoost, M. and Pavon, C. 2007. Survival of Phytophthora capsici oospores in soil. Phytopathology (Supplement) 97 (7): S6.
• Babadoost, M. and Pavon, C. 2007. Survival of Phytophthora capsici in soil. First International Phytophthora capsici Conference. 27-29, 2007, Islamorada, Florida. Program Book: 11.
• Jasinski J., Pilcher, C., Weinzierl, R., Babbadoost, M., Maynard, M., Gunter, C., Breinling, J. Myers, N., Welty, C., LeBoeuf, J. and Roddy, E. 2007. Assessing IPM Adoption of North Central Region Pumpkin Growers. Poster presentation, National Entomological Society, 2007.
• Pavon, C.F., Babadoost, M. and Lambert, K.N. 2008. Quantification of Phytophthora capsici oospores in soil by sieving-centrifugation and real-time polymerase chain reaction. Plant Dis. 92:143-149.

Progress 01/01/06 to 12/31/06

Outputs
Illinois, with annual production of approximately 10,000 acres of processing pumpkins (representing more than (90% of processing pumpkins produced in the U.S.) and 10,000-12,000 acres of jack-o-lantern pumpkins, ranks first in pumpkin production among the states in the nation. Phytophthora blight, caused by Phytophthora capsici, is the most serious threat to production of pumpkins and other cucurbit crops (cucumbers, gourds, melons, squashes) in Illinois. Yield losses of up to 100% in pumpkin and other cucurbit fields have been recorded. This pathogen survives as oospores (thick-walled spores) in soil for several years and attack host plant throughout the growing season. At present, there is no single method to provide adequate control of P. capsici on pumpkins and other crops. There is no measurable resistance in pumpkin cultivars against P. capsici. The goal of this research is to develop effective strategies for management of Phytophthora blight in pumpkin fields. This report is focusing on detection and quantification of oospores of P. capsici in soil. A sucrose-centrifugation method was developed to extract oospores of P. capsici from soil. The relationship between the number of oospores recovered from soil and the number of oospores incorporated into the soil was Ŷ= -0.75 + 1.21X -0.02X2 (R2=0.98), where Ŷ = log10 of the number of oospores recovered from soil and X = log10 of the number of oospores in soil. The oospores were germinated after treating with 0.1% KMnO4 solution for 10 minutes. Using the developed sucrose-centrifugation method, oospores of P. capsici were successfully extracted from soil samples collected from commercial fields. A real-time quantitative polymerase chain reaction (QPCR) protocol was developed to assay the density of P. capsici oospores in soil. PCR-inhibition was avoided by extracting oospores from soil using the sucrose-centrifugation method. The relationship between the amount of DNA measured and the number of oospores of P. capsici included in the test was Ŷ = - 3.57 - 0.54X + 0.30X2 (R2 = 0.93), where Ŷ = log10 (ng of P. capsici DNA), X = log10 (number of oospores). In 2004, a trial has been set up at University of Illinois Vegetable Research Station to study survival of oospores of P. capsici in soil. Oospores of P. capsici were incorporated into four different soil types, infested soils with P. capsici oospores were placed in the oospore-proof mesh and buried at 0, 2, 10, and 25 cm deep. The soil samples were recovered after 1, 3, 6, 12, and 24 months and tested for presence of viable P. capsici oospores. Two years after burring infested soils in the ground, P. capsici oospores were recovered from soils and germinated. The results showed that P. capsici oospores survive in the soil for more than two years.

Impacts
The pumpkin industry is the most valuable vegetable industry in Illinois. Results of this research will help to assure that the pumpkin industry will continue to be a significant component of the Illinois agricultural economy. With the new finding in this research, we are getting closer to offering effective cropping rotations for management of Phytophthora blight of cucurbit crops.

Publications

• Babadoost, M. and Islam, S.Z. 2005. Efficacy of selected fungicides for control of Phytophthora blight (Phytophthora capsici) in processing pumpkin diseases in Illinois in 2005. Pages 36-42 in 9th Annual Illinois Fruit and Vegetable Research Report.
• Pavon, C. and Babadoost, M. 2006. Determining density of Phytophthora capsici oospores in soil. Pages 507-514. In: Proceedings of Cucurbitaceae 2006, September 17-21, 2006, North Carolina State University, Asheville, NC, USA.
• Babadoost, M. and Islam, S.Z. 2005. Fungicide evaluation for control of Phytophthora blight of processing pumpkin. Fung. and Nemat. Tests 61: V023.
• Babadoost, M., Swiader, J.S. and Islam, S.Z. 2006. To develop and implement effective tactics for management of Phytophthora blight of vegetables. Pages 2-3. In USDA-CSREES, North Central Region Integrated Pest Management Grants Program.
• Babadoost, M., Islam, S.Z., Pavon, C. and Tian, D. 2006. Strategies for management of Phytophthora blight (Phytophthora capsici) of cucurbits. 5th National Integrated Pest Management Symposium, April 4-6, 2006, St. Louis, Missouri. Abstract of papers: P084, page 83.
• Pavon, C. and Babadoost, M. 2006. Detection and quantification of Phytophthora capsici oospores in soil with real-time quantitative polymerase chain reaction. Phytopathology 96:S91, In: Abstracts of papers of joint meeting of APS, CPS, and MSA. July 29-August 2, 2006, Quebec City, Canada.
• Babadoost, M. 2006. Phytophthora blight of cucurbits. Illinois Fruit and Vegetable News, Volume 12, Number 8: 82.

Progress 01/01/05 to 12/31/05

Outputs
Illinois with approximately 22,000 acres of pumpkins ranks first in pumpkin production among the states. About 90% of the commercial processing pumpkins in the United States are produced in about 10,000 acres in Illinois. Phytophthora blight, caused by Phytophthora capsici, has become one of the most serious threats to production and industry of pumpkins and other cucurbit crops (cucumbers, gourds, melons, squash) in Illinois. Yield losses of up to 100% in pumpkin fields have recorded. This pathogen survives as oospores (thick-walled spores) in soil for several years and attack host plants at any time during the growing season. At present, there is no single method to provide adequate control of P. capsici on pumpkins and other crops. There is no measurable resistance in pumpkin cultivars against P. capsici. A recommended practice for reducing the incidence of this disease in pumpkin fields would be an integrated approach combining crop rotation, seed treatment, induction of plant resistance, sanitation, and management of field moisture. This research was initiated to develop effective strategies for management of Phytophthora blight in pumpkin fields. The first step in developing effective integrated approach for management of Phytophthora blight in pumpkin fields is developing effective cropping rotations and evaluating efficacy of fungicides for control of the disease. For developing effective cropping rotations, survival of the pathogen (P. capsici) in the soil must be determined. To determine survival of P. capsici in soil, we initiated studies to develop a reliable method for extraction and enumeration of oospores of the pathogen in soil. Five soil types were infested with oospores of P. capsici to produce 102, 103, 104, or 105 spores per 10-g of air-dried soil. Each 10-g of infested soil was processed using our sieving-sucrose-centrifugation method to extract and enumerate oospores in the soil samples. The relationship between oospores recovered and oospores incorporated into soil was Ŷ= -1.311+1.472X-0.047X2. Also, soil samples were collected from eight commercial fields in three counties with a history of Phytophthora blight, and oospores of P. capsici were successfully extracted from soil using the above-mentioned sieving-sucrose-centrifugation method. A trial was conducted in an irrigated field near Pekin, IL. The field was naturally infested with P. capsici. Processing pumpkin cultivar Dickinson was planted in May. Seeds were slurry-treated with Apron XL LS (0.64 fl oz/100 lb seed) two days prior to sowing. Seeds were sown 18-inch apart in single-row plots, 20-feet long. Seventeen fungicides in 23 different combinations (23 treatments) were applied to soil and foliage. Also, an untreated check was considered. Due to the drier weather and soil conditions than normal, there was not a considerable incidence of seedling death in the plots. Some of the treatments provided satisfactory control of Phytophthora vine blight and fruit rot. Vine infection and fruit rot were significantly higher in untreated plots than some of the fungicide-treated plots. Marketable fruit number and yield were the lowest in untreated check plots.

Impacts
The pumpkin industry is the most valuable vegetable industry in Illinois. Results of this research will help to assure that the pumpkin industry will continue to be a significant component of Illinois agricultural economy.

Publications

• Babadoost, M. and Islam, S.Z. 2005. Fungicide evaluation for control of Phytophthora blight of processing pumpkin. Fung. and Nemat. Tests 61(Submitted).