Relative attractiveness of incomplete and complete blends of synthetic pheromone to male obliquebanded leafroller (Lepidoptera: Tortricidae) moths in a flight tunnel and in apple orchards: implications for sex pheromone-mediated mating disruption of this species.

The relative attractiveness of synthetic Choristoneura rosaceana (Harris) pheromone consisting of the major compound Z-11-tetradecenyl acetate (Z11-14:OAc), or the major compound plus one, two, or all three of the minor compounds E-11-tetradecenyl acetate (E11-14:OAc), Z-11-tetradecenol (Z11-14:OH), and Z-11-tetradecenal (Z11-14:Ald), in amounts similar to those in the natural pheromone, was compared in a flight tunnel and in apple orchards. In the flight tunnel, there was an increase in the proportion of moths that were activated when E11-14:OAc was combined with the main compound, but no detectible additional increases in response with the addition of Z11-14:OH and Z11-14:Ald. The time required for activation was twice as long when using the major compound than when using the major compound and one or more of the minor compounds. There was a trend of increase in the proportion of males initiating the take-off, lock-on, close-in, and touchdown phases of upwind flight when progressively more complete blends were used. The time required for the initiation of these behavioral phases was statistically similar for each treatment. The proportion of moths landing at the pheromone source was 10 times greater when using the complete blend than when using the main compound alone. Similar results were obtained in apple orchards, where the four-compound blend was 17-55 times more attractive than the main compound. The superior attractiveness of the four-compound pheromone compared with the major compound, or to the major compound plus the minor compound E11-14:OAc, suggests that it would be the most effective synthetic pheromone if competitive attraction were an important mechanism of disruption in this species.