Spatial and temporal changes in aphid/parasitoid distributions following an insecticide application to winter wheat.

Abstract

The densities and distributions of cereal aphid, primary and hyperparasitoid populations were monitored in a winter wheat crop before and after a pyrethroid insecticide application at two dose rates. Aphid and parasitoid populations were significantly reduced, with differing patterns of reinvasion and recovery of populations occurring over time in 4 ha plots. The importance of scale and the spatial arrangement of hosts to the evaluation of pesticide side effects on parasitoids is briefly discussed.