Ground Beetle Activity in Apple Orchards under Reduced Pesticide Management Regimes

Analyses of pitfall traps in Washington and Oregon apple orchards revealed that predatory ground beetles (Coleoptera: Carabidae) were strongly susceptible to applications of broad-spectrum, neural-active insecticides. When compared with orchard blocks managed without broad-spectrum insecticides, orchard blocks under conventionally managed regimes had significantly lower populations of ground beetles. The carabid species Pterostichus adstrictus Eschscholtz and P. melanarius Illiger constituted 89% of all ground beetles collected over two growing seasons. Laboratory feeding studies with Pterostichus spp. and Harpalus pensylvanicus showed that these ground beetles have the potential to be important predators of overwintering larvae of codling moth [Cydia pomonella (L.)] and of cutworm larvae (Lepidoptera: Noctuidae).