Toxicity of insecticides used in the Brazilian melon crop to the honey bee Apis mellifera under laboratory conditions

This study aimed at evaluating the toxicity of insecticides used in melon crop (Cucumis melo L.) on adults of Apis mellifera L. (Hymenoptera: Apidae) under laboratory conditions. Three ways of exposure were used: direct spraying, feeding with insecticide contaminated diet, and contact with sprayed leaves. Bees were exposed to the insecticides abamectin, acetamiprid, cartap chloride, chlorfenapyr, cyromazin, deltamethrin, thiamethoxam, flufenoxuron, and pyriproxyfen at the highest dosages recommended by the manufacturers for the melon crop in Brazil. Results indicated that, regardless of how the bees were exposed to insecticides, thiamethoxam, abamectin, and chlorfenapyr were extremely toxic to adults of A. mellifera. Acetamiprid, deltamethrin, and cartap chloride were most toxic when directly sprayed on the bees. Cyromazin and pyriproxyfen caused low mortality rates to A. mellifera, whereas flufenoxuron caused moderate mortality when fed to adult bees.