Timed, metered sprays of pheromone disrupt mating of Cadra cautella (Lepidoptera: Pyralidae)

A controlled release system for dispensing insect pheromones and other semiochemicals at a specified release rate over long periods of time was developed and tested. Large quantities of pheromone were stored in pressurized canisters of metered semiochemical timed release system (MSTRS) devices kept in rooms with little thermal insulation at ambient field temperatures for more than 90 d during the summer. The devices were tested in experimental storage rooms for their efficacy as mating disruptants by releasing pheromone only or pheromone-pluspyrethroid. Pheromone required for mating disruption experiments was released upon demand from canisters for the desired duration, with no detectable decrease in effectiveness in promoting suppression of mating as the canisters aged. MSTRS devices placed in 3 m × 3 m × 3 m rooms disrupted up to 100% of the mating attempts of the almond moth, Cadra cautella (Walker) (Lepidoptera: Pyralidae), in populations consisting of freely flying virgin males and females at a 2:1 ratio, respectively, for 24 h, and disrupted up to 92% of the mating attempts for 72 h. Disruption of mating was measured directly by recapture of moths and examination of the females' bursa copulatrices for the presence of spermatophores, which were used as indicators of successful mating encounters. MSTRS devices emitting different doses of pheromone were tested for mating disruption. Strong sources, dosed with 50 μg of pheromone per spray at 15 min intervals, were the most efficacious, promoting more than 90% mating disruption, and their effect was independent of either moth population density or number of MSTRS devices used per room. Sources receiving 5 μg of pheromone per spray at 15 min intervals disrupted 60%-70% of mating, which still represented a significant level of disruption. Mating disruption was enhanced (to >80%) by the addition of 1% natural pyrethrin extract to the 5 μg pheromone sprays; 96.1% of the male population was dead after 24 h.