Development of Microbial Communities to Suppress Tomato Foliar Pathogens

View the project final report

Commodities

• Vegetables: tomatoes

Practices

• Crop Production: greenhouses
• Pest Management: biological control, prevention
• Production Systems: organic agriculture

Currently, there are no reliable methods for controlling bacterial diseases of tomatoes beyond copper-containing bactericides, antibiotics or plant defense activators. Alternative approaches, such as biological control agents have the potential to substitute or combine with IPM strategies employed by farmers to provide more robust disease control. The overall goal of this project is to test the feasibility of different cost-effective techniques for transferring foliar microbial communities to provide a management option of bacterial diseases of tomato. Plant material will be collected from commercially grown tomato fields in Pennsylvania and will be cycled to select for foliar microbial communities that suppress tomato bacterial diseases. Seedlings will be inoculated with these selected communities using several methods followed by a challenge with either the speck or spot pathogens to assess disease progression. The microbial communities transfer methods that exhibit the least amount of disease will then be further tested to identify the optimal amount of plant material required for disease suppression and if plant material from the previous growing season can be used in our selected method(s). We believe our ‘community approach’ has the potential to be superior to commercial single organism formulations in that our approach will provide more robust and consistent disease control resulting from multiple distinct mechanisms of pathogen control. Additionally, if this approach is successful, it could potentially be applied for controlling additional foliar fungal and bacterial vegetable crop pathogens. Results will be communicated in publications and presentations geared towards farmers, extension personnel and agricultural researchers.

In this project, I propose to develop transfer methods of tomato foliar microbial communities effective at suppressing either bacterial spot or speck. I hypothesize that a community of microorganisms will provide increased plant health and prevent disease development to a greater extent than a single organism application, and that these microbes can be efficiently and economically transferred with dry plant material.

The specific objectives of this proposal are:
1. Develop a method for transferring communities via leaf application during germination in the greenhouse. Expected outcome: This objective will identify the efficacy of foliar microbial community transfer using plant material.
2. Determine the amount of plant material required for detectable disease suppression. Expected outcome: This objective will establish the amount of plant material needed for disease suppression to inform the economic feasibility of each transfer method.
3. Assess the efficacy of plant material that is stored over an extended period of time for disease reduction. Expected outcome: This objective will indicate whether plant material can be stored long-term prior to application and still retain effectiveness.

Overall, this project will provide a method for designing a more sustainable crop system for protecting crops from diseases in the short-term, and potentially long-term in the field. This research will provide the critical data that will aid in selecting methods that could be incorporated into current growing practices in an economically feasible manner.