The Effects of Cover Crops on Squash Bug (Anasa tristis) Populations

Organic squash growers struggle with various diseases and insect pests that affect squash yield. One important pest, the squash bug (Anasa tristis), causes damage by feeding on xylem of cucurbits. The bug is also responsible for transmitting a bacterium, Serratia marcescens. This bacteria causes cucurbit yellow vine disease, which causes cucurbits to yellow, wilt, and decline in 5-100% of plantings (Bruton et al., 2003). Currently, organic growers utilize row covers, organic insecticides, and field sanitation techniques to control this pest, however, none of these methods are 100% effective. Field studies were conducted to analyze the affect of growing adjacent cover crops on squash bug populations. Sunn hemp (Crotalaria juncea), cow pea (Vigna unguiculata), and buckwheat (Fagopyrum esculentum) were planted adjacent to yellow squash during summer 2014. Fields were scouted weekly and squash harvested every 2-3 days. Results from the first trial suggest squash bugs showed no preference for any cover crop treatment (Poisson distribution, p=0.066) and squash yields were highest in control plots (1 way ANOVA, p=0). Slight adjustments were made in trial two to encourage better growth of cover crops and decrease competition between squash and cover crops. In trial two, control plots had the most squash bug egg masses (Poisson distribution, p=0) and buckwheat plots had fewer squash bug adults than the control (Poisson distribution, p=0.026) Yields were comparable in control, buckwheat, and cowpea plots (1 way ANOVA, p=0.036). The experiment will be repeated in the coming season to obtain more conclusive results.