Control of multiple species of lepidopterous insect pests using a mating disrupter and reduced pesticide applications in Japanese pear orchards.

Efficacy of a mating disrupter against multiple species of lepidopterous insects was tested in Japanese pear orchards in Tottori, Japan during 1997, with the goal of reducing the amounts of insecticides and acaricides applied. Three experimental plots were set up as follows: (1) conventional control plots in which insecticides and acaricides were sprayed 14 times; (2) treatment with the mating disrupter, "Confuzer-p(R)" and application of insecticides reduced to 20% of the conventional control (Plot 1); and (3) use of the mating disrupter and 35% of the conventional control insecticide application (Plot 2). The mating disrupter seemed to be effective against Homona magnanima, Adoxophyes honmoi and Carposina niponensis in terms of the number of male moths caught in the sex pheromone trap and the percentage of injured fruit. Reduced applications of insecticides conserved to some degree the predators of spider mites, especially the predaceous thrips, Scolothrips takahashii. Acaricide application was therefore reduced to one time in Plot 1 and none in Plot 2 as compared with twice in the conventional control plot. The occurrence of minor insect pests, Eumeta japonica, Ascotis selenaria and Euproctis spp., tended to increase in Plots 1 and 2. These insects injured the pear shoots, although injury to the fruit was negligible. The cost of the control measures in Plots 1 and 2 was around 1,400 US dollars per ha as compared with 1,300 dollars in the conventional control plot.