Laboratory bioassays were conducted to evaluate the effects of a series of insecticides concentrations onlife history and life-table parameters of Neoseiulus californicusis an important natural enemythat feeds on many spider. The European red mite, Panonychus ulmi, an important pest in Iran apple orchards, was used as prey. The insecticides testedcaused a significant reduction in the net fecundity/fertility throughout the trial. The results indicated that adverse effects of the insecticideson population growth of N. californicus were significant. The intrinsic rate of increase (r m ) the net reproduction rate (R 0 ) and finite rate of increase (λ) were significant reduced in treated female compared to control. It could beconcluded that lethal concentrations can significantly reduce the population growth of N. californicus and this should be considered in integrated pest management programs.
