Influence of weeds within Zea mays crop plantings on populations of adult Diabrotica barberi and Diabrotica virgifera virgifera

Abstract

The influence of weeds in corn plantings on abundance of adult Diabrotica barberi Smith & Lawrence and Diabrotica virgifera virgifera Le Conte (Coleoptera: Chrysomelidae) was examined. Four treatments were established: corn without weeds, corn principally with broadleaf weeds, corn principally with grassy weeds, and corn with a mixture of broadleaf and grassy weeds. Significantly greater numbers of D. barberi adults were collected from corn in treatments with broadleaf weeds than from corn in treatments without broadleaf weeds for both years of the study. Relative abundance of adult D. barberi on corn was not significantly different between treatments containing grassy weeds and treatments without grasses either year. Neither broadleaf nor grassy weeds significantly affected adult populations of D. virgifera virgifera either season; however, significantly more western corn rootworm beetles were collected from mixed weeds than from broadleaf or grassy weeds in 1989. The presence of broadleaf weeds in corn plantings could result in greater numbers of D. barberi adults on corn plants, and possibly greater oviposition.