The Effect of Flowering Cover Crops on Beneficial Insects

Nicole Quinn, Dan Brainard, and Zsofia Szendrei
Department of Entomology, Michigan State University

Presented at the All Scientist Meeting (2015-04-15 to 2015-04-16 )

Cucumbers (Cucumis sativus) are one of the most widely grown crops of the North Central Region, yet they are also one of the most likely to face pollination and biological control deficits. Natural enemies and pollinators require additional nutritional and habitat resources that are not found in conventional agricultural fields. The addition of flowering cover crops within the field could provide these resources. As of now, information on this topic, especially in cucumbers, remains limited. We hypothesized that pollinator and natural enemy abundance would increase in plots containing flower strips and that the effect would be greatest in the rows closest to the flower strips. Five flower strip treatments were used: 1) cucumbers (control), 2) crimson clover (Trifolium incarnatum), 3) buckwheat (Fagopyrum esculentum), 4) yellow mustard, (Brassica hirta), or 5) sweet alyssum (Lobularia maritima). Flowers were planted within the field in a randomized complete block design with six replications in the 2015 growing season. While honey bees (Apis mellifera) and most native bees were not affected by flowering cover crop treatment, squash bees (Peponapis pruinosa) were significantly less abundant in plots containing buckwheat or mustard compared to plots containing only cucumber. Distance away from the floral strips was not a significant factor. Natural enemies were generally more abundant in flowering cover crop treatments than in the cucumber (control) treatment. The inclusion of flower strips in cucumber fields can increase beneficial insect activity, however, care must be taken in selecting flowering cover crops, as flowers that support natural enemies may inhibit pollinators or vice versa.