Interference with the mate-finding communication system of the Chinese tortrix Cydia trasias (Lep., Olethreutidae) using synthetic sex pheromones

Abstract: Interference with the mate-finding communication system of Cydia trasias (Meyrick) using sex pheromone dispensers (60% E8,E10-dodecadienyl acetate and 40% E8,E10-dodecadien-1-ol, 0.5 mg/dispenser) was investigated in three plots of the Chinese scholar-tree, Sophora japonica L., in Beijing, China, in 2000. Treatments were evaluated by pheromone-baited traps, caged virgin females, pupating and hibernating populations on tree trunks, and assessment of larval damage in petioles and seed pods. Six to eight natural rubber septum dispensers were placed in each tree at the pheromone-treated plots at three separate periods: at the beginning of overwintering generation flight, the first- and the second-generation flights. Application of pheromone dispensers reduced the incidence of mating of virgin females in treated plots relative to those in the control plots. Pheromone-baited trap catches were lowered on average by 96%, suggesting a high level of disruption. Average larval density on tree trunks was significantly lower in the pheromone-treated plots than in the untreated control plots. The mean percentage of Chinese scholar-tree petioles infested with first- and second-generation larvae, and seed pods infested with third-generation larvae was significantly greater in untreated control plots than in pheromone-treatment plots. These results suggest that disruption of pheromone-based communication in C. trasias is prospective, with synthetic sex pheromone on trees in urban environments.