PROLONGED ADAPTATION AS POSSIBLE MATING DISRUPTION MECHANISM IN ORIENTAL FRUIT MOTH, CYDIA (EQUALS GRAPHOLITA) MOLESTA

The effects of pheromone preexposure on flight behavior of male Orient al fruit moth, Cydia molesta, were investigated in laboratory experime nts using a wind-tunnel and in an orchard through insect releases at t he center of a grid of pheromone traps. In the wind-tunnel experiments , the proportion of insects performing various behavioral phases was f ound to depend on the intensity and duration of the adapting stimulus and the recovery time allowed between exposure and measurement, indica ting adaptation of at least some elements of the sensory system. The o rchard experiments exhibited similar adaptation effects at similar exp osure levels, causing the entry of treated insects into the traps to b e delayed compared to controls and a reduction in insects caught for t he 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 syn thetic pheromone for insect control through mating disruption.