Modification of responses by Campylomma verbasci (Heteroptera: Miridae) to pheromone blends in atmospheres permeated with synthetic sex pheromone or individual components

Trapping experiments were conducted in orchards to test the hypothesis that exposure of the mullein bug, Campylomma verbasci (Meyer), to atmospheres permeated with its synthetic sex pheromone, a 94:6 blend of butyl butyrate (BB) and (E)-crotyl butyrate (CB), or BE or CB alone, would alter the pheromone responses of males toward off-ratio blends. Exposure to the natural 94:6 blend shifted the response preference away from the natural ratio to blends enriched in BB, including a 99:1 blend, which is normally significantly less attractive than the natural ratio. In an atmosphere permeated with CB, male mullein bugs were as responsive to blends containing 20, 33, and 43% CB, up to seven times the natural percentage, as they were to the 94:6 blend. In an atmosphere permeated with BB, responses to five blends ranging from 94:6 to 99:1 BB:CB were not significantly different, whereas in an untreated atmosphere blends of 98:2 and 99:1 were significantly less attractive than the 94:6 blend. Individual components appeared to disrupt pheromone communication primarily through the creation of a sensory imbalance and modified interpretation of pheromone blend ratios, whereas disruption by the complete pheromone blend apparently involves several mechanisms, including false-trail following and camouflage. Disruption of pheromone communication was most effective with the natural 94:6 sex pheromone blend.