Knowledge of the effects of pesticides on biological control agents is necessary for successful implementation of integrated pest management programs. Laboratory bioassays were conducted to evaluate the effects of diazinon and acetamiprid on life history and life-table parameters of Neoseiulus californicus as an important natural enemy of spider mites. The insecticides tested caused a significant reduction in the net fecundity/fertility throughout the trial. The results indicated that adverse effects of the insecticides on population growth of N. californicus were significant. For diazinon the intrinsic rate of increase (rm), the net reproduction rate (R0) and finite rate of increase (λ) were reduced 5.75, 15.5 and 1.2- fold in comparison to the control treatment, respectively. These criteria for acetamiprid were 1.53, 2.08 and 1.7- fold in the same order. The intrinsic rate of increase (rm), the net reproduction rate (R0) and finite rate of increase (λ) significantly reduced in treated female compared to control. It could be concluded that lethal concentrations can significantly reduce the population growth of N. californicus and this adverse effect should be considered in integrated pest management programs.
