ABSTRACT

A resistance-monitoring program was established at the University of Arkansas in 2002 to annually gauge changes in major pest susceptibilities to insecticidal proteins in transgenic crops and shifts in regional and temporal susceptibility to major modes of action common to critical conventional insecticides. Nineteen colonies of Lepidoptera were collected and assayed for susceptibility to Cry1Ac and Cry2Ab proteins. The bollworm, Helicoverpa zea, exhibited more variability in susceptibility then other species tested. Variation among field colonies was 15-to 22-fold. Laboratory susceptible colonies were 5-to 80-fold more susceptible then some field colonies. Susceptibilities of field collected insects to acephate, cypermethrin, malathion, and spinosad were measured by a treated glass vial technique. Base-line data were collected for several species of noctuid moths and important hemipteran pests. An overview of first year results and benchmark data are presented in this paper.