Interseeding cover crops into established corn fields affects invertebrate abundance and diversity and elevates the activity of generalist predators.

Abstract

Ecologically simplified corn fields lack the plant diversity-derived resources necessary for supporting robust beneficial insect populations capable of preventing pest outbreaks. Interseeding cover crops into established corn is a way that farmers can diversify cropland plant communities and restore ecosystem functions. Here, we examine how foliar, epigeic, and subterranean arthropod communities differ between corn monocultures and corn interseeded with cover crops. We also examine how predator activity and predation are affected by interseeded cover crops in corn fields. Predators, herbivores, numerous individual taxa, and all combined arthropods were more abundant on the soil surface in interseeded corn fields. Adding cover crops also increased the number of epigeic species. Within the subterranean environment, community structure was similar in the bare soil and interseeded corn fields, and only 4 commonly collected species differed in abundance. Below-ground arthropod diversity increased when cover crops were interseeded in corn fields. Community characteristics in the corn foliage were not affected by the cover crops. Twice as many wax moth (Galleria mellonella (L.)) sentinel larvae were eaten by generalist predators in cover-cropped corn (45.5%) than in corn monocultures (22.6%). The effect of cover crops on corn stand density and yield varied significantly between study locations. Diversification of the corn agroecosystem by interseeding cover crops had a spatially compartmentalized effect on invertebrates in corn fields, favoring the abundance and diversity of surface-dwelling invertebrate fauna and predator activity. This management tool should be further explored by researchers and farmers, as it is a viable method for conserving biodiversity and bolstering biological control of crop pests.