Population viability analysis: a new approach for estimating the compatibility of insecticides and biocontrol agents in IPM programs

Pesticides still play a major role in the control of insect pests. In IPM programs, insecticides are often used with biocontrol agents. To avoid damaging biocontrol agents, insecticide applications are either timed to avoid exposure to the beneficial species or the insecticides are selective whereby they are more toxic to the pest species than to the biocontrol agent. Several approaches have been developed to determine the compatibility of biocontrols and insecticides and they are often based on acute mortality estimates. However, what has been lacking is an approach that takes into account the total effect (lethal and sublethal) of insecticides at the population level. In this paper, we will present a new method to determine the effects of insecticides on biocontrols. The method consists of simple stage-based stochastic matrix models based on life history data and insecticide susceptibility. The models are designed to determine whether a biocontrol agent will go to extinction during a growing season based on insecticide exposure. We will focus on braconid parasitoids in this study.