Disruption of Light-Brown Apple Moth Epiphyas-Postvittana (Walker) (Lepidoptera, Tortricidae) Trapping in Nelson, New-Zealand

Abstract

Disruption of lightbrown apple moth trapping was tested as a prelude to assessment of mating dis- ruption; polyethylene dispensers releasing the known sex pheromone components, (E)-11-tetradecenyl acetate and (E,E)-9,ll-tetradecadien-l-yl acetate, at an estimated rate of 25 mg ha-' per hour in apple orchards in Nelson, New Zealand. A total of 2953 wild and 850 laboratory-reared males were marked and released at 16 sites in two pheromone-treated and two untreated blocks. No captures were recorded in sticky traps baited with virgin females or synthetic pheromones in pheromone-treated blocks, but 455 males were caught in untreated blocks, indicating complete prevention of trapping in the presence of the dispensers releasing synthetic pheromone. Individual dispensers released an estimated 4000-fold more pheromone per hour than females. Recapture of wild and laboratory-reared males averaged 28% and 31% respectively, in untreated blocks and surrounding traps. Removal of dispensers resulted in renewed capture inside previously treated blocks. Dispersal distances of wild and laboratory-reared males were not significantly different inside untreated blocks, but the mean time taken before recapture was twice as great for laboratory-reared moths (P<O.05). Wild males showed a greater tendency to disperse out of blocks (P<O.05). Dispersal distances exceeded 400 m for several moths. The daily survival or retention rate of wild moths inside release blocks was estimated to be 63%, although this rose to 74% when external traps were included. A maximum age of 19 days was recorded. Female moths mated with equal frequency when caged with males in pheromone-treated or untreated blocks.