Evaluation of aerosol devices for simultaneous disruption of sex pheromone communication in Cydia pomonella and Grapholita molesta (Lepidoptera: Tortricidae).
A two-year study was conducted evaluating Puffer® aerosol dispensers (Suterra LLC, Bend, OR, USA) for mating disruption of codling moth, Cydia pomonella (L.), and the oriental fruit moth, Grapholita molesta (Busck). The Puffer® dispenser consists of a pressurized metal canister loaded with pheromone active ingredients dissolved in solvent and housed within a circuit-controlled, plastic dispensing cabinet programmed to release an aerosol spray of pheromone at regular intervals. Puffers® were deployed at the label-recommended rate of 2.5 ha-1 and released ca. 5-10 mg of pheromone (depending on treatment) per 15 min during a 12-h cycle beginning each day at 15:00 h for the duration of the season. In 2005, commercially-managed apple plots (3.2-4.9 ha) were treated with Puffers® releasing both species' pheromone simultaneously (dual-species) or with twice the number of adjacently-deployed Puffers® (4-6 m apart) releasing each individual species' pheromones (single-species), while maintaining comparable overall release rates of pheromone between these two treatments. Plots 100 m away and not treated with pheromone served as the control. Disruption of male C. pomonella and G. molesta orientation to pheromone-baited traps was 46-75 and 91-98%, respectively, in Puffer®-treated plots compared with untreated controls. There was no statistical difference in moth disruption between plots treated with dual-species and single-species Puffers®. Fruit injury was not statistically different between Puffer®-treated plots and control plots not receiving pheromone. In 2006, disruption of male moth orientation to traps was 24-26 and 84-97% in Puffer®-treated plots (2.9-5.7 ha) for C. pomonella and G. molesta, respectively, compared with untreated controls. During this season, fruit injury was lower in pheromone-treated plots compared with untreated controls at mid-season, but not at pre-harvest. Combining the pheromone of both species into single Puffer® units did not decrease efficacy of disruption compared with deploying twice as many Puffers® releasing a similar amount of each individual species' pheromone suggesting that multi-species disruption using Puffers® is a viable option. However, we conclude that the efficacy of disruption attained with low-densities (2.5 ha-1) of Puffers® at the moth densities recorded in this study is insufficient for effective control of C. pomonella without input of companion insecticides.