WHY PUFFERS WORK: DETERMINING THE EFFECTS OF RESIDUAL RELEASES ON CONTROL OF CODLING MOTH IN WALNUTS AND PEARS

The effective area of a pheromone plume from a single puffer, a high-dose aerosol emitter, was shown to disrupt male location of pheromone traps completely for an area ca. 75 meters by 230 meters. The end of the puffer plume appears to have exceeded the length of the orchard. Suppression of traps baited with virgin females showed a similar pattern with 100% suppression directly downwind of the puffer. Lateral suppression appears to occur for ca. 75 meters and the degree of suppression was a function of the position of the female baited traps relative to the center line of the plume. Leaves downwind of the puffer unit up to 60 meters appear to absorb pheromone from the plume and re-release the pheromone over time. In wind tunnel trials, moths would orient to plume from the pre-exposed leaves across the entire sample range. Thus, secondary release of pheromone may prove to be an important means by which pheromone levels are maintained at high levels within the tree canopy. The infrastructure for an enzyme-linked immunosorbent assay was established with our lab to look at movement by moth species in walnuts and pears. The technique was refined in the laboratory during most of the summer, and a late season field trial confirmed our ability to mark and capture moths treated with a protein marker, e.g. eggs. Thus wild codling moths can be marked using commercial insecticide application equipment and tracked for movement in response to the puffer pheromone plume.