Flight and Sexual Activity of the European Corn Borer1,2,3

Abstract

Although the European corn borer, Ostrinia nubilalis (Hübner), began flight shortly after dusk, capture of feral males in traps baited with virgin females or feral males and females captured in light traps and studies of released insects in cultivated and uncultivated corn showed that this early evening activity is not oriented toward mating. Sexual activity peaked between 2400 and 0100 h, and most of it took place in tall (57.5–117.5 cm), dense foxtailgrass ( Setaria faberii Herrn. and S. viridis (L.) Beaur.), where large numbers of both sexes aggregated. Aggregation and sexual activity occurred as much as 100 m from the nearest cornfield. The grass habitat is of major importance in the aggregating phenomenon though pheromone emission by females may also have a part. Techniques employed to disrupt pheromone communication between the sexes in cornfields might be futile because mating could occur in dense vegetation outside the cornfield.