MD. ASLAM KHAN

The available isolates of B. thuringiensis were evaluated for their efficacy against the Bihar having caterpillar both alone and in combination with a synthetic insecticide endosulfan. Lowest LC„ was noticed in case of Btk HD-73 and highest in case of Btk path-1. In ascending order LC,. values were as Btk HD-73, Bt sotto, Bt aizawai, Bt N 1 C 1, Btk HD-1, Bt thuringiensis, Dipel, Bt entomocidus, Bt galleriae and Btk Path-] . The lowest LC90 was found in case of Bt sotto whereas, lowest Lcs and LC„ were recorded in case of Bt NIC1. Twenty four hours after treatment the highest larval mortality, 86.67 per cent, was observed in case of endosulfan, 0.07 with Dipel, 0.075 per cent. However, eight days after treatment mixture of endosulfan with Dipel at 0.035 and 0.03 per cent, respectively caused 96.67 per cent larval mortality.