Surveying parasitoids of cucurbit pests in conventional and organic cucurbits in Kentucky

Cucurbits are an important, high-value crop for both conventional and organic farmers and are valued at $1.43 billion of the annual $11 billion US vegetable industry. Two major pests in this system are the striped cucumber beetle (Acalymma vittatum) and the spotted cucumber beetle (Diabrotica undecimpunctata howardi), both of which can damage plants by feeding and spread of bacterial wilt (Erwinia tracheiphila). Much research has be placed on controlling these pests through chemical controls, plant breeding programs, and pest barriers, such as row covers; but they still remain a formidable problem for both conventional and organic growers. The use of biological control agents for the control of these pests has been understudied, but preliminary studies have shown that two Tachinidae parasitoids (Celatoria setosa and C. diabronticae) and two Braconidae parasitoids (Centisus diabrotica and Syrrhizus diabroticae) are found in Eastern North America (Smyth and Hoffmann,2010). The major goals of this project are to expand upon previous studies of these parasitoids and survey their presence in Kentucky. Our study focuses on comparing parasitoid populations from four conventional and four organic cucurbit growing farms in central Kentucky. Bi-weekly surveys of cucumber beetle and parasitoid populations began at the time beetle emergence (early May 2015) and will be continued until the first hard frost (mid-November 2015). The results of this study will help us to identify important cucumber beetle parasitoids in Kentucky, and understand their population changes throughout the growing season on both conventional and organic farms.  We hope to apply what we learn to lead to new, more sustainable pest control options that will be applicable for cucurbit growers in our state and region.

Smyth, R.R., M.P. Hoffmann. 2010. Seasonal incidence of two co-occurring adult parasitoids of Acalymma vittatum in New York State: Centistes (Syrrhizus) dibroticae and Celatoria setosa. BioControl 55: pp. 219-228