Toxicity of pesticides to Tetranychus urticae Koch (Acari:Tetranychidae) and their side effects on Neoseiulus californicus (Acari:Phytoseiidae)

ABSTRACTThe present study was conducted to determine the direct and residual effects of five pesticides, namely abamectin, bifenthrin, dimethoate, propargite and sulphur against Tetranychus urticae and residual toxicity of these pesticides to Neoseiulus californicus adults. In the laboratory trials, except dimethoate, all the pesticide treatments caused 100% mortality of T. urticae adults within 24–48 hours. When toxicity to eggs was tested, the egg mortality for all pesticide treatments was significantly higher than the control. Except dimethoate, all the pesticides caused >90% egg mortality. In potted bean plants, all the pesticide treatments caused significant mortality of T. urticae populations over control up to 21 days. The residual effects of pesticides were tested on T. urticae and N. californicus using a leaf disc system in the laboratory. Mites were exposed to freshly sprayed leaf disc and after at 3, 7, 14 and 21. Abamectin showed higher efficacy against T. urticae but low toxicity against N. c...