Effect of Difluhenzuron on the Canopy Arthropod Community in a Central Appalachian Forest

Abstract
Little is known of the effects of diflubenzuron on the nontarget forest arthropod community. We hypothesized that the use of this compound in gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), control may cause indiscriminate reduction of nontarget arthropods. This, in turn, might be an important loss of food for forest birds and small mammals. In a 2-yr replicated study we sampled canopy arthropods with pole pruners for up to 3 mo following application of diflubenzuron. Due to a strong trend over time and large between-tree variance in canopy arthropod abundance and taxonomic richness, intensive sampling was required to reveal the treatment effect. Besides reductions in gypsy moth larvae, significant reductions due to diflubenzuron application were found mainly in canopy macrolepidoptera and non-lepidopteran mandibulate herbivores. Sucking herbivorous insects, microlepidoptera, and predaceous arthropods were not affected.