Selectivity of Five Insecticides for Codling Moth 1 Control: Effects on the Twospotted Spider Mite 2 and Its Predators

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Abstract
Five insecticides were tested against Laspeyresia pomonella (L.), and their effects on Tetranychus urticae (Koch) and its predators were determined. The broadspectrum insecticides permethrin (0.013%), azinphos-methyl (0.05%) and leptophos (0.045%) gave equal control of L. pomonella under a 3-weekly programme of 7 sprays. Poorer control was given by the selective chemicals chlordimeform (0.05%) and diflubenzuron (0.05%). Both chlordimeform and permethrin suppressed T. urticae populations. No predators of mites were found on pennethrin treated trees and very few were found on trees sprayed with the organophosphates. Chlordimeform appeared relatively harmless to all stages of Stethorus spp. and diflubenzuron appeared harmless to Stethorus adults, but was toxic to the eggs. Small numbers of predatory mites of 3 species were recovered from diflubenzuron treated trees towards the end of the season.