REPO - A SIMULATION-MODEL THAT EXPLORES COLORADO POTATO BEETLE (COLEOPTERA, CHRYSOMELIDAE) ADAPTATION TO INSECTICIDES

A simulation model (REPO) was developed to predict the rate of resistance development in Colorado potato beetle, Leptinotarsa decemlineata (Say), given various genetic, biological, and management conditions. Values used in exploring variables in the model were chosen to reflect the range of possibilities encountered in field populations of Colorado potato beetle. REPO is different from other resistance management models in that it is temperature-driven, considers age-specific selection, describes the pattern of immigration of colonists, and uses survivorship functions to describe dynamic relationships among genotypes during insecticide selection. The life history of Colorado potato beetle in North Carolina and other areas is presented as a backdrop to model exploration of some of the unique features of this pest that could influence resistance evolution. Foremost among ecological and management factors influencing rate of resistance development were the arrival period of colonizing beetles, timing of insecticide applications, action thresholds, and age-specific selection. Relevance of these findings to management of Colorado potato beetle and future research on this insect is discussed.