A slide-dip bioassay using laboratory colonies revealed that apple aphid, Aphis pomi DeGeer, was more susceptible to esfenvalerate and methomyl, but less susceptible to azinphosmethyl than spirea aphid, A. spiraecola Patch. Susceptibility to endosulfan and chlorpyrifos was not significantly different between the two species. For A. pomi, order of insecticide toxicity was esfenvalerate > methomyl > endosulfan > chlorpyrifos > azinphosmethyl. For A. spiraecola, order of toxicity was esfenvalerate > methomyl > azinphosmethyl > chlorpyrifos > endosulfan. Knowledge of which species was present in a given apple orchard and the selective use of insecticides could result in more efficient aphid control while reducing toxicity to predators used in IPM programs.
Author notes
2Published with the approval of the Director of the West Virginia Agricultural and Forestry Experiment Station as Scientific Article No. 2154. This research was supported with funds appropriated from the Hatch Act. This article reports the results only. Mention of a proprietary product does not constitute an endorsement or a recommendation for its use by West Virginia University or USDA.
3Appalachian Fruit Research Station, USDA-ARS, Kearneysville, WV 25430.