none The susceptibility of male and female Pholetesor ornigis (Weed) to the pyrethroid insecticides permethrin, fenvalerate, and deltamethrin, the organophosphorous insecticides azinphosmethyl and phosmet, and the carbamate insecticide methomyl, was compared in the laboratory using two populations from Norfolk County, Ontario. Female P. ornigis were more susceptible than males to permethrin. There was no sexual difference in the susceptibility of P. ornigis to the other five insecticides tested. The implications of these results for the biological control potential of P. ornigis in commercial apple orchards are discussed. Results suggest that P. ornigis from Norfolk County have low levels of resistance to permethrin (3.3-fold), fenvalerate (2.2-fold), and methomyl (4.1-fold).