Imidacloprid Tolerance in the Green Peach Aphid (Myzus persicae) in North Carolina: The Role of Geographic Origin and Color

Neonicotinoid insecticides are a widely used family of active ingredients that offer a systemic protection against green peach aphid (Myzus persicae) in tobacco (Nicotiana tabacum) fields in North Carolina. In this experiment we wanted to determine if there are aphid clones with high tolerance to imidacloprid, and if geographic origin and color might affect tolerance to the pesticide. We collected aphids from infested tobacco plants from four different research stations in North Carolina. Aphids were separated by collecting point within each station and three to five different subpopulations from each research station were maintained. Average LC50 to the pesticide was measured by exposing adult aphids to artificial diet with five different concentrations of laboratory-grade imidacloprid for 72 hours. We fitted a Generalized Linear Model, with a binomial response (Dead and Total aphids) and color and geographic origin as factors. We determined the best model using AIC and tested the effect of each factor. Results show that tolerance to imidacloprid varies between 1.1 mg/L to 14.8 mg/L in adults and 1.8 mg/L to 5.4 mg/L in nymphs. The clones that are more tolerant are not geographically clustered and color seem to have a weak effect in adults.