Effect of mating disruption using the major component of the sex pheromone, (z)-7-eicosen-11-one, on the peach fruit moth, Carposina sasakii Matsumura, was more pronounced at lower moth densities. When supplemented with adequate insecticide sprays, the treatment caused a drastic decrease in the pest population even at extremely high levels. Release of the common pheromonal component onto leafrollers of the tribe Archipini, (z)-11-tetradecenyl acetate, prevented the population recovery of the apple tortrix, Archips fuscocupreanus Walsingham, the Asiatic leafroller, A. braviplicanus Walsingham, and the summer fruit tortrix, Adoxophyes orana fasciata Walsingham, under conditions of reduced insecticide sprays, The effect on the last species, however, decreased remarkably under outbreak conditions. Also, a significant increase of the incidence of the brown tortrix, Pandemis heparana (Schiffermuller et Denis), occurred in a few pheromone-treated fields. Mixture of the two pheromone components, (z)- 10-tetradecenyl acetate and E4, z10-tetradecadienyl acetate, in the ratio of 10:3 showed a significant disruptive effect on the mating of the apple leafminer, Phyllonorycter ringoniella (Matsumura).