Biology and Management of the Pecan Nut Casebearer (Lepidoptera: Pyralidae)

Abstract

The pecan nut casebearer, Acrobasis nuxvorella Neunzig, is a key pest of pecan nut production throughout the pecan producing regions of the central and southwestern United States and northern Mexico. Economic loss is primarily due to first-generation larvae that feed internally in developing nutlets soon after pollination in the spring. Damage by second-generation and third-generation larvae can also result in economic loss. We summarize pecan nut casebearer distribution, life history, crop injury, and current management practices including orchard scouting, monitoring adult activity with pheromone traps, and chemical, biological and regulatory controls. Insecticides are the sole means of controlling pecan nut casebearer but must be properly timed to kill young larvae before they tunnel into pecan nuts. Effective management requires orchard scouting to assess egg abundance and nut entry by larvae to determine the need for and optimum timing of insecticide treatment. An on-line, degree-day model, PNCforecast, uses pheromone trap data to predict oviposition activity and optimum dates for sampling orchards to assess pecan nut casebearer egg infestations. This IPM program is enhanced by the availability of diacylhydrazine insecticides that are toxic to Lepidoptera larva but preserve beneficial insects that suppress secondary pests of pecans.