Evaluating the Compatibility of Bacillus thuringiensis var. Kurstaki with Common Insecticides for Use in IPM Programs

Abstract

This study investigates the compatibility of selected insecticides with Bacillus thuringiensis var. kurstaki (Bt), a widely used microbial biopesticide, to assess their suitability for incorporation into integrated pest management (IPM) strategies. Compatibility was determined by evaluating Bt colonies and percentage inhibition following exposure to three different concentrations of each insecticide (10⁵, 10⁷, and 10⁹ cfu/ml). The results revealed a consistent trend in colony development and inhibition across all concentrations. Among the insecticides tested, Chlorantraniliprole 18.5 % SC exhibited the highest compatibility at 10⁹ CFU/ml, supporting the maximum Bt colony growth (12.67 Cfu/ml) and showing the lowest inhibition (4.73 %). Flubendiamide 39.35 % SC and Emamectin benzoate 5 % SG followed with colony growth of 11.33 and 10.77 Cfu/ml and inhibition percentages of 14.81 % and 19.02 %, respectively. Conversely, Profenophos 50 % EC showed the lowest compatibility, with a significantly reduced colony growth (3.67 Cfu/ml) and the highest inhibition rate (72.40 %). These findings highlight the importance of compatibility assessments in IPM programs, ensuring that chemical and microbial agents can be effectively combined without compromising the efficacy of beneficial biocontrol organisms. Such evaluations are essential for promoting sustainable pest management practices and enhancing the performance of Bt based formulations in the field.