Investigating the effects of sun hemp (Crotolaria juncea) intercropping on cucumber beetle (Diabrotica and Acalymma spp.) populations and plant vigor in a zucchini agroecosystem

Sunn hemp (Crotalaria juncea) is a tropical cover crop that offers many potential benefits when intercropped into vegetable systems. The effects of sunn hemp intercropping were studied at the Central Maryland Research and Education Center from June 2009 to August 2010. Eight field plots were established in which bare ground zucchini plots were compared to sunn hemp intercropped zucchini plots. Insect counts, plant measurements and harvest data were regularly collected from each plot throughout the growing season. By the end of the season striped cucumber beetle (Acalymma vittatum) populations were lower in sunn hemp plots. Similarly, spotted cucumber beetle (Diabrotica undecimpunctata) populations were lower in sunn hemp plots. Zucchini plants grown in sunn hemp intercropped plots were less vigorous than those in bare ground plots.