Developing Methods for Determining Survival of Phytophthora capsici in Soil for Establishing Effective Cropping Rotations for Sustainable Vegetable Production

View the project final report

• 2006 annual report

Commodities

• Agronomic: corn, soybeans
• Fruits: melons
• Vegetables: beans, cucurbits, eggplant, peas (culinary), peppers, sweet corn, tomatoes
• Additional Plants: ornamentals

Practices

• Animal Production: preventive practices
• Crop Production: application rate management, intercropping
• Education and Training: demonstration, display, extension, farmer to farmer, on-farm/ranch research, participatory research, technical assistance, workshop
• Farm Business Management: budgets/cost and returns, risk management
• Natural Resources/Environment: biodiversity, soil stabilization
• Pest Management: cultural control, economic threshold, field monitoring/scouting, genetic resistance, integrated pest management, prevention, sanitation, soil solarization, weather monitoring, weed ecology
• Production Systems: agroecosystems
• Soil Management: organic matter, soil analysis
• Sustainable Communities: sustainability measures

Approximately 30,000 acres are planted to cucurbits, eggplant, peppers, and tomatoes in Illinois. This represents 90% of the commercial processing pumpkins produced in the United States. Annual production of cucurbits, eggplant, peppers, and tomatoes in the North Central region exceeds 140,000 acres. Phytophthora blight, caused by Phytophthora capsici, has become one of the most serious threats to production of cucurbits, eggplant, peppers, and tomatoes in the North Central region, causing yield losses of up to 100%. P. capsici is a soilborne pathogen and survives as oospores in the soil. This pathogen causes damping-off, foliar blight, and fruit rot on the host plants. There is no method available to provide adequate control of P. capsici on vegetables. No cucurbit cultivar with measurable resistance against P. capsici is available. Several control measures need to be used in a management program to minimize crop losses to this disease. Crop rotation would play a significant role in the management of this disease. Although host range of P. capsici was recently determined, there are not effective cropping rotations available for management of Phytophthora blight of vegetable. This is because there is no reliable method for determining P. capsici inoculum, thus survival of the pathogen, in the soil. This proposal is a two-year project to develop reliable techniques for detection and quantification of P. capsici in soil for establishing effective cropping rotations for sustainable vegetable production. The specific objectives of this research are as follows: (i) to develop a reliable wet sieving-centrifugation method for extraction and enumeration of oospores of P. capsici from soil; (ii) to study survival of oospores of P. capsici in soils; and (iii) to develop a quantitative polymerase chain reaction (QPCR) protocol for determining oospore density of P. capsici in soil. The results of this research will be presented to growers, food processors, extension personnel, and at the regional and national meetings. Results also will be published in newsletters, websites, and refereed journals (i.e., Plant Disease and HortScience). Implementation of the results of this research will be rapid and the growers will benefit from the findings in this research.

Short-term outcomes of this research would be development of reliable methods for detection and quantification of Phytophthora capsici in soil. A wet-sieving-centrifugation method to extract and enumerate oospores of P. capsici from different soil types will be established. Also, a quantitative polymerase chain reaction (QPCR) procedure for determining density of oospores of P. capsici in soil will be developed. Intermediate- and long-term outcomes of this study will be determining survival of P. capsici in soil, establishing effective cropping rotations, reducing use of pesticides, establishing effective strategies for management of one of the most destructive diseases of vegetables, and increasing profitability of vegetable production; thus, establishing sustainable vegetable production and food security in the North Central region.