DISRUPTION OF PHEROMONE COMMUNICATION IN 3 SYMPATRIC LEAFROLLER (LEPIDOPTERA, TORTRICIDAE) PESTS OF APPLE IN BRITISH-COLUMBIA

Fruittree leafroller, Archips argyrospila (Walker), obliquebanded leaf roller, Choristoneura rosaceana (Harris), and European leafroller Arch ips rosana (Robinson), all use Z11-14:OAc and E11-14:OAc as components of their species-specific pheromone blends. Small-plot experiments (0 .09 ha) were conducted in the Okanagan Valley of British Columbia to e valuate the effects of atmospheric permeation with different concentra tions of Z11-14:OAc and E11-14:OAc, applied in a ratio of 93:7, on phe romone communication of these sympatric species. The relative response of male moths to synthetic and natural pheromone-baited traps in pher omone-treated and untreated plots was used to measure disruption of ph eromone communication. The pheromone-disruption blend was released by polyethylene tube-type dispensers applied at various densities. Catche s of A. argyrospila in synthetic pheromone traps decreased by <92 and 97% when pheromone was applied at rates of 5-10 mg/h/ha and 20-40 mg/h /ha, respectively. Catches of A. argyrospila in virgin female-baited t raps were reduced by 99% at pheromone application rates of 20-40 mg/h/ ha. Catches of C. rosaceana and A. rosana in synthetic pheromone-baite d traps decreased by 88-96% when the pheromone disruptant was applied at rates of 20-40 mg/h/ha. In pheromone-disrupted plots, more male A. argyrospila were caught in traps baited with pheromone blends of C. ro saceana and A. rosana containing a higher percentage of Z11-14:OAc tha n the reported pheromone blend of A. argyrospila. These results sugges t an alteration of the normal pheromonal response of A. argyrospila on exposure to a high concentration of Z11-14:OAc for a sustained time.