Simultaneous disruption of pheromone communication in Choristoneura rosaceana and Pandemis limitata with pheromone and antagonist blends

In British Columbia, trapping and wind-tunnel studies demonstrated that (Z) -9-tetradecenyl acetate (Z9-14:OAc), a minor component of the sex pheromone for Pandemis limitata, acted as a pheromone antagonist to a sympatric spec ies, Choristoneura rosaceana. Addition of >1% Z9-14:OAc to the four-compone nt C. rosaceana pheromone in a wind tunnel resulted in significant reductio ns in the proportion of male C. rosaceana that wing fanned, locked on to th e plume in flight, oriented upwind, and made source contact, compared to th e responses to the pheromone alone. Disruption of pheromone communication w as tested in 33.3 x 33.3-m plots, at a release rate of 10 mg/ha/hr using Co nrel fiber dispensers. Z9-14:OAc applied alone did not disrupt orientation to virgin-female-baited traps for either C. rosaceana or P. limitata. A 1:1 mixture of Z9-14:OAc and the four-component C. rosaceana pheromone was as effective as the pheromone alone at disrupting orientation of C. rosaceana males to virgin-female-baited traps, demonstrating that disruption apparent ly did not occur through false-trail following. The 1 : 1 mixture of Z9-14: OAc and the C. rosaceana pheromone also reduced catches of P. limitata mal es in virgin-female-baited traps, but not significantly more than the 83% d isruption caused by the pheromone alone. Therefore, the C. rosaceana pherom one could be used alone or with Z9-14:OAc to disrupt communication and, pre sumably, mating in both leafrollers simultaneously.