Dispersal of Adult European Corn Borer (Lepidoptera: Crambidae) Within and Proximal to Irrigated and Non-irrigated Corn

The European corn borer, Ostrinia nubilalis</it> (Hübner), causes economic damage to corn, Zea mays</it> L., throughout the Corn Belt. Because this insect has become the primary target of Bacillus thuringiensis</it> Berliner (Bt) transgenic corn, current efforts addressing the management of O. nubilalis</it> resistance to Bt corn require information on adult European corn borer dispersal and factors affecting its dispersal. In 1998 we conducted mark-release-recapture, release-recapture, and caged-mating studies to directly measure and compare local dispersal patterns of O. nubilalis</it> adults within and proximal to irrigated and non-irrigated cornfields. Releases of marked adults were made corresponding to the first and second flight of O. nubilalis</it> in eastern Nebraska. Adult dispersal was significantly different between irrigated and non-irrigated cornfields. Released adults tended to remain in and near irrigated cornfields, but dispersed out of and away from non-irrigated cornfields. When released at the edge of the cornfield, neither male nor unmated female O. nubilalis</it> displayed an initial tendency to move out of irrigated corn and into the mixed smooth bromegrass (Bromus inermis</it> Leyss) and broadleaf-weed field edge. Mating efficiency in a late-season cornfield was not significantly different than in dense foxtail (Setaria</it> spp.). Generally, we found that adult O. nubilalis</it> dispersal may vary depending on variables such as action-site availability and agronomic practices and their interaction with O. nubilalis</it> life history.