Higher dose of B.bassiana (10⁸ fungal spores/ml) showed higher effectiveness against third instar larvae of Helicoverpa armigera with percent mortality of larvae up to 10 DAT. The efficacy inclined gradually with advancement of time but persisted up to 10 days after treatment to induce 90 percent mortality. The B.bassiana (10⁷ fungal spores/ml) at 10 DAT shows 76.66 percent mortality. From the result it is concluded that the mortality was time dose dependent. As the dose increased the mortality was also increase and vice-versa.