Investigations of mechanisms of pheromone communication disruption of Choristoneura rosaceana (Harris) in a wind tunnel

Although atmospheric treatment with synthetic pheromone is used commerciall y to control several lepidopteran pests, little is known about how mate-fin ding behavior is altered by this procedure. Mechanisms of disruption of the mate-finding behavior-of Choristoneura rosaceana (Lepinoptera: Tortricidae ) were examined in wind tunnel bioassays. Male moths were exposed to synthe tic sex pheromone or pheromone components prior to or during upwind Fight t o a calling virgin female The proportion of males successfully contracting a calling female was reduced only when the synthetic pheromone treatment wa s presented simultaneously. A synthetic source of the attractive four compo nent pheromone placed upwind of a calling female was more effective than a less attractive true-component blend in achieving disorientation. Habituati on of the central nervous system does not appear to be a significant factor in disruption of mate-finding behavior of male C. rosaceana, as exposure t o pheromone prior to the bioassay did not alter the proportion of males tha t achieved subsequent upwind Fight. Disruption of mate-finding behavior of C. rosaceana in a wind tunnel is probably the result of a combination of me chanisms including adaptation of antennal receptors, camouflage of the fema le-produced plume, and false-trail following which contributed to the addit ive disruption effect observed with the most attractive four-component pher omone.