Vol. 9, Issue 7, Part S (2025)

The colonies of novel PDKV Bacillus thuringiensis strains from the wettable powder and suspension concentrate formulations raised on L.B. medium were counted using colony counter. Among the suspension concentrate formulation, the highest spore count was recorded in PDKV Bt SY-4-75 SC with 17.6×10⁸ CFU/ml, followed by PDKV Bt SA-20-75 SC with 16.5×10⁸ CFU /ml, PDKV Bt SGn-4-75 SC with 14.7×10⁸ CFU/ml and PDKV Bt SGn-5-75 SC with 13.2×10⁸ CFU/ml. Among the wettable powder formulations, the highest spore count was recorded in PDKV Bt SY-4-25 WP with 5.85×10⁸ CFU/ml, followed by PDKV Bt SA-20-25 WP with 5.5×10⁸ CFU/ml, PDKV Bt SGn-4-25 WP with 4.9×10⁸ CFU/ml and PDKV Bt SGn-5-25 WP with 4.4×10⁸ CFU/ml. All the formulations recorded CFU counts above the standard Bt kurstaki 5% WP (5 × 10⁷ spore/mg) commercial formulation. The studies revealed suitability of L. B. medium for culturing of all the novel PDKV Bt strains.