Codling Moth, Cydia pomonella, Captures in Monitoring Traps as Influenced by Proximately to Competing Female-Like- vs. High-Releasing Pheromone Point Sources

This research tested the hypothesis that a codling moth male, Cydia pomonella L., selects the sex pheromone plume of highest concentration when encountering overlapping plumes of differing concentrations. A plume of normal concentration generated by a female-like lure (7 ηg/h), and a plume of high concentration generated by a polyethylene sex pheromone “rope” dispenser, Isomate-C® Plus (6,000 ηg/h), were deployed at various distances and elevations from a standard monitoring trap (Pherocon® VI delta trap) deployed in an abandoned apple orchard. Moth captures in lure-baited traps in the tree canopy were significantly inhibited when the plume from the rope was nearby. However, the concentrated plume from the rope positioned below the monitoring trap at distances of 50 cm or more did not influence moth capture significantly. When the plume from the rope was positioned at the same elevation as the lure, moth captures were reduced significantly only when the separation was 50 cm or less. Our data: 1) falsify the hypothesis that codling moth males are able to select plumes of normal pheromone concentration when exposed simultaneously to plumes of high vs. normal concentrations; 2) confirm that codling moth males favor more vs. less concentrated plumes; and 3) provide further support for competitive attraction as the disruptive mechanism for the Isomate-C® Plus.