Comparing the effectiveness of sexual communication disruption in the oriental fruit moth (Grapholitha molesta) using different combinations and dosages of its pheromone blend

Abstract

The relative efficacy of disruptant blends comprised of different combinations of the Oriental fruit moth's pheromone components was determined in field tests. Disruption was evaluated by comparing male moth catch at synthetic and female-baited traps in disruptant and non-treatment areas. Three atmospheric dosages of a 8-dodecenyl acetate (93.5%Z∶6.5%E) blend, representing two successive 10-fold decreases in concentration (2.5 × 10⁻² g/hectare/day to 2.5 × 10⁻⁴ g/hectare/day) were tested alone and in combination with an additional percentage of (Z)-8-dodecen-1-ol. Male moth orientation to traps was eliminated in plots exposed to the two highest binary acetate dosages. However, significantly more males were captured in synthetic-baited traps in the lowest acetate-alone treatment, indicating a diminution of disruption efficiency. In contrast, inclusion of (Z)-8-dodecen-1-ol in the disruptant blend effected essentially complete disruption of orientation at all concentrations tested. Mating success ofG. molesta pairs confined in small cages apparently was not affected by the presence of relatively high concentrations of the binary acetate and the acetate-alcohol blends. This suggests that habituation and/or adaptation of male response, at least for comparatively “close-range” behaviors, did not occur.