Phenology of Lymantria dispar (Lepidoptera: Lymantriidae), male flight and the effect of moth dispersal in heterogeneous landscapes

A model of Lymantria dispar development was assembled from the published literature and used to predict the period of male moth flight in the United States. Model predictions were compared with observations made with pheromone traps in several locations throughout the United States but especially in Virginia, West Virginia and North Carolina between 1995 and 1996. The model was found to provide accurate and unbiased forecasts of the dates of 5%, 50% and 95% cumulative trap catch, particularly at lower elevations. In areas of high topographic diversity (such as West Virginia), deviations between model output and observations were minimized by basing predictions of 5% and 50% cumulative catch on minimum elevation within neighborhoods of 25-81 km(2). This model of L. dispar male flight phenology can be used to time the deployment and retrieval of pheromone traps in intensive or extensive monitoring programs. However, a better understanding of moth movement is needed to fully explain the patterns of local trap catch.