The effectiveness of spinosad and microclimate for use in integrated pest management of thrips on greenhouse cucumbers in Ontario (Amblyseius cucumeris, Orius insidiosus, Encarsia formosa)

Insecticide resistance and the demand for pesticide reduction have led to increased interest in integrated pest management (IPM) programs for the control of western flower thrips (WFT). Spinosad was effective against immature and adult WFT by direct, direct/residual and residual contact applications. It had minimal impact on the biological control agent (BCA), Amblyseius cucumeris, and timed applications should improve its compatibility with Orius insidiosus and Encarsia formosa. Increasing the efficacy of BCA also has IPM potential. A. cucumeris exhibited both increased predation and oviposition at a higher temperature. These functions were not affected by changes in vapor pressure deficit (VPD). Predation by Orius was not influenced by temperature or VPD. Spinosad's unique mode of action, selective toxicity, and limited persistence make it an ideal biocide for greenhouse IPM. Information on the effect of microclimate on BCA biology can be used to modify seasonal release rates of BCA and thus further improve the effectiveness of thrips IPM on greenhouse cucumbers.