The objectives of this research were to determine the effects of water, humidity, UV light and temperature on the release rate of oriental fruit moth, Grapholita molesta (Busck), pheromone from 3MTM microencapsulated sprayable pheromone (Phase V formulation). The application of water to pheromone samples was a principal factor in pheromone release from microcapsules. The driving force for the release of pheromone was likely the swelling and contraction of microcapsules resulting from daily addition and evaporation of water. Photographs of microcapsules to which water was added daily showed that this swell-shrink stress process resulted in the rupture of microcapsules. Samples to which water was not added did not exhibit this swell-shrink stress process, and pheromone release was negligible. Pheromone was released more rapidly under low compared with high humidity levels, probably because water evaporated more quickly and completely at low humidity. After two weeks of adding water, microcapsules were sufficiently ruptured to sustain a steady release rate without re-application of water. In all experiments where water was added, the release rate of pheromone was highest during the first two weeks. This effect was most prominent at higher temperatures, probably because water evaporated more quickly, enabling pheromone molecules to diffuse faster. UV light had a minimal effect on the release of pheromone.
Species 1: Lepidoptera Tortricidae Grapholita molesta (Oriental Fruit Moth)
Keywords: controlled release, sprayable pheromone
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