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POSTERS: Biological control

Plant metabolite-based resistance to Oidium neolycopersici in organic- and high tunnel-grown tomato
Erica Fealko - University of Kentucky. Emily Pfeufer- University of Kentucky, Pradeep Kachroo- University of Kentucky, April Lamb- University of Kentucky

Powdery mildew of tomato, caused by Oidium neolycopersici, can result in significant yield loss in high tunnel production. Induction of plant defenses with non-synthetic materials may be an avenue for disease management in organic systems. To this end, a fermentation by-product, which contains multiple naturally occurring plant defense inducers, was assayed to determine its effect against powdery mildew in a high tunnel tomato production study. Treatments included Nordox (copper hydroxide), and Companion (Bacillus subtilis GB03) as grower standards, along with a filtered and unfiltered version of the fermentation by-product. High tunnel-grown tomato plants were inoculated with O. neolycopersici (3.7 x 104conidia/ml) and foliar symptoms were rated. The fermentation by-product significantly reduced (P<0.05) powdery mildew compared to the inoculated control and Companion, and was similar to the protectant standard Nordox. These results suggest that the fermentation by-product reduces powdery mildew similar to a protectant-based grower standard. Molecular analyses suggest that the plant defense inducers present in the fermentation by-product confer resistance by priming for plant defense. Together, these results suggest that fermentation-by product can be as effective as currently marketed disease management products, and its efficacy is derived at least partially by induced resistance.