(Rogers, Hale and Wszelaki)

Cucurbit crops that are largely grown in Tennessee include pumpkin, cantaloupe/muskmelon, summer squash, cucumbers and watermelon. These crops are increasingly grown as an alternative to tobacco and are a very important component in the agricultural economy of the state. Transmission of bacterial wilt is one of the most significant problem facing cucurbit production, and management of the cucumber beetles that vector the disease is a challenge in organic production.

Cucumber beetles are an annual problem in Tennessee, and populations overwinter and increase when left unmanaged. In addition to vectoring bacterial wilt, beetles chew stems and leaves and feed directly on fruit, reducing both marketable yield and quality.

Our study aims to test a novel biopesticide on the complex of disease-vectoring cucurbit pests- three species of cucumber beetles: Diabrotica undecimpunctata, Diabrotica virgifera and Acalymma vittata (Coleoptera: Chrysomelidae).

This research would benefit both conventional and organic growers in the state. Organic specialty crops are sold for premium prices, and seed is expensive. When pest populations reach threshold levels, organic growers need a viable solution to protect their crop. Conventional growers depend heavily on the broad spectrum pesticides carbaryl and bifenthrin to manage beetles, but could also benefit from rotation with biopesticides with a different mode of action that may be less detrimental to natural enemies. MOI-201(Marrone Organic Innovations) is a botanical biopesticide that is effective against both chewing and sucking insect pests and has a different mode of action than pyrethrum or neem, so has potential in resistance management programs. In preliminary tests, MO1-201 (0.6% AI) resulted in 86% mortality Diabrotica virgifera adults in 48 hr. Efficacy against D. undecimpunctata and Acalymma vittata is currently unknown. This experiment will test the efficacy of MOI-201 against these beetles, and in conjunction with Beauveria bassiana, a biopesticide with known efficacy, and carbaryl, a conventional pesticide on melons and pumpkins.

This grant proposal was funded by the IR-4 Biopesticide Program. The goal of the IR-4 Biopesticide Program is to further the development and registration of biopesticides for use in pest management systems for specialty crops or for minor uses on major crops. This project will begin in Spring 2010.