In the past most inexpensive pesticides readily available to farmers have been effective against pests but harmful to predators and parasitoids. As a result, pesticide use has been largely incompatible with integrated pest management programs. However, recent losses of some traditional broad-spectrum pesticides (e.g. phosdrin, parathion) along with the advent of newer more selective pesticides is now raising the possibility of more effective and efficient pest management via a combination of biological and chemical control. Through a series of field and laboratory experiments, we explored ways of reducing our reliance upon pesticide spraying while fostering control by natural enemies. We developed a protocol for controlling three aphid species: Cabbage aphids (Brevicoryne brassicae), Green peach aphids (Myzus persicae) and Turnip aphids (Hydaphis pseudobrassicae), which are the principle pests of crucifer crops in the Pacific Northwest United States. This protocol consisted of limited spraying of a selective insecticide, Fulfill such that the effectiveness of a specialist parasitoid, Diaeretilla rapae and a generalist coccinellid, Coccinella septempuncatata was enhanced. To further our understanding of the interactions of these different control techniques, we examined pesticide effects on the two natural enemies of crucifer aphids, by developing life tables after exposure to a range of pesticide concentrations. Life table data was used to pick field concentrations of Fulfill. Field results were compared to acute mortality and life table data to determine which gave the best estimate of field effectiveness.
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA