Abundance of Nontarget Foliage-Dwelling Insects After Insecticide Treatment for Adult European Corn Borer (Lepidoptera: Pyralidae)

Species composition and seasonal abundance of the insect fauna were identified from the foliage of mating and resting sites of European corn borer (ECB), Ostrinia nubilalis (Hubner). A total of 99,519 foliage-dwelling insects was collected during 1983 and 1984. Homoptera, Hemiptera, Hymenoptera, and Diptera accounted for 89% of the total fauna captured. The Chalcididae were the most abundant insects captured from the foliage of action sites. The major herbivores identified from ECB adult action sites were Athysanus argentarium Metcalf, Draeculacephala anticox (Walker), and Leptopterna spp. Coleomegilla maculata (De Geer) and Hippodamia convergens (Guerin-Meneville) were the most abundant predators inhabiting the grassy canopy of ECB adult action sites. Peak predator abundance coincided with early season population peaks of the foliage herbivores. The role of ECB adult action sites as a possible source of predators for Iowa cornfields is discussed. The effects of carbaryl and fen valerate applied for spring- and summer-generation adult ECB control were tested on the foliage-dwelling insects in action sites. Only one species, A. argentarium , was significantly reduced by spring applications of carbaryl and fenvalerate to the foliage of ECB adult action sites. A. argentarium was significantly reduced for 28 d post treatment during 1983 and for 7 d in 1984. Summer adult control had minimal impact on the foliage insects. Foliage predator populations were not negatively affected by the application of insecticides. Therefore, application of carbaryl and fenvalerate for controlling ECB adults in action sites resulted in minimal disruption of the foliage-dwelling insect community.