Evaluating Response of Mass-Reared and Irradiated Navel Orangeworm, (Lepidoptera: Pyralidae), to Crude Female Pheromone Extract.

The navel orangeworm, (Lepidoptera: Pyralidae), is a key pest of almonds and pistachios in California. Larvae directly feed on nuts, reducing quality and yield, and adults can introduce fungi that produce aflatoxins. The development of sterile insect technique (SIT) is currently being explored as a management tool for this pest. Large quantities of are mass-reared, irradiated, and shipped to California from a USDA APHIS facility in Phoenix, AZ. Preliminary field releases of sterile from this facility resulted in poor recovery of males in pheromone traps, raising concerns that mass-reared male may not be responding to pheromone from virgin females. In this study, a wind tunnel was used to evaluate the response of both irradiated and non-irradiated mass-reared males to crude pheromone extract from females, and their performance was compared to two strains of locally reared non-irradiated . While initial responses associated with pheromone detection where similar between mass-reared and locally reared moths, a lower proportion of the mass-reared moths ultimately made contact with the pheromone source. Surprisingly, the addition of irradiation did not further decrease their performance. While mass-reared moths respond to pheromone, their ability to locate and make contact with the pheromone source appears to be impeded. The underlying mechanism remains unclear, but is likely related to damage incurred during the mass-rearing and shipping process.