SUSCEPTIBILITY OF MALE CODLING MOTH (LEPIDOPTERA, TORTRICIDAE) TO AZINPHOSMETHYL IN MISSOURI

Male codling moth, Cydia pomonella (L.), from four commercial apple or chards and one experimental research orchard located in central and we st-central Missouri were examined for susceptibility to azinphosmethyl during the 1993 and 1994 field seasons. Moths were captured in sex ph eromone traps and assayed by topical application of technical grade ma terial. The LD50 Of the most susceptible population, located in the ex perimental research orchard, was 0.08 mu g per moth, and the LD50 Of t he most resistant population was 1.10 mu g per moth. Three of the four commercial orchard sites had populations of codling moth with a resis tance ratio significantly greater than that of the susceptible populat ion.