The effects of Bacillus thuringiensis var. kurstaki (Berliner) on adults of Apis mellifera Linnaeus were evaluated. The bioassays were carried out under controlled conditions at 25±2ºC, RH 70±10% and 12-h photophase. Adults of A. mellifera were exposed to the commercial product Dipel® PM. The following methods were used: direct spraying; supplying Bt with honey aqueous solution; and by a Candy paste added to Bt. B. thuringiensis caused mortality on A. mellifera adults, independent of the method used, except at 0.25 g of Bt/100 mL added to the honey aqueous solution. B. thuringiensis added to the Candy paste showed CL50 and CL90 of 0.325 g and 2.127 g of the product to 60 g of Candy paste, respectively. Dipel® PM added to the honey aqueous solution showed CL50 and CL90 of 1.403 g and 7.759 g of B. thuringiensis/100 mL, respectively. Infection symptoms by B. thuringiensis were identified on bees adult and by isolation of this bacterium, the toxicity of B. thuringiensis on A. mellifera was confirmed.
Bee; toxicity; biological insecticide
