SUMMARY
Compatibility studies are essential for the integration and simultaneous use of chemical and biological pest control methods since they are necessary for an Integrated Pest Management (IPM) program. In this work, the aim was to evaluate the compatibility of insecticides used in soybean and cotton crops for pest control with Bacillus thuringiensis (Bt). The in vitro inoculation technique was used with B. thuringiensis var. kurstaki and B. thuringiensis var. aizawai, in culture medium containing the following insecticides: beta-cyfluthrin (Bulldock®), methomyl (Bazuka®), thiamethoxam + lambda-cialotrina (Engeo Pleno®), zeta-cypermethrin (Fury 200®), acetamiprid (Saurus®), bifenthrin + carbosulfano (Talisman®) and bifenthrin (Talstar®), in Petri dishes. The Petri dishes were taken to the B.O.D. (Biological Oxygen Demand), at a temperature of 30 ± 1 ºC, 70 ± 10% RH (relative humidity) and a photophase of 12 h, for 24 hours. Colony growth was measured, and Colony Forming Units (CFU) counted in the total area of the Petri dish. The product that allowed growth to be significantly equal to or higher than the control was established as compatible, and the one that did not allow growth or was significantly less than the control was incompatible. It was found that all insecticides were classified as incompatible with the bioinsecticide.