Prolonged Adaptation as Possible Mating Disruption Mechanism in Oriental Fruit MothCydia (=Grapholita) molesta

The effects of pheromone preexposure on flight behavior of male Oriental fruit mothCydia molestawere investigated in laboratory experiments using a wind-tunnel and in an orchard through insect releases at the center of a grid of pheromone traps. In the wind-tunnel experiments, the proportion of insects performing various behavioral phases was found to depend on the intensity and duration of the adapting stimulus and the recovery time allowed between exposure and measurement, indicating adaptation of at least some elements of the sensory system. The orchard experiments exhibited similar adaptation effects at similar exposure levels, causing the entry of treated insects into the traps to be delayed compared to controls and a reduction in insects caught for the highest preexposure concentration. The levels of pheromone exposure required to produce significant adaptation were, however, found to be much higher than could be expected under conditions of release of synthetic pheromone for insect control through mating disruption.