A field bio-efficacy of Brigade-BL (Beauveria bassiana) an entomopathogenic fungi was evaluated against mealy bugs (Meconellicoccus hirsutus) on Thompson Seedless grapes at National Research Centre on Grapes, Manjri, Pune during 2014-15. The experiment was conducted in RBD with five replications on foundation pruning and fruit pruning. Results obtained revealed that application of Brigade-BL @ 5.0 ml/L with two sprayings resulted in reduction of mealy bug colonies upto 67.82% in foundation pruning as compared to control. Likewise, at fruiting pruning, after fifth spray of Brigade-BL @ 5.0 ml/L recorded 75.68% reduction in mealy bug population and increase in fruit yield of 92.44% over control. Similarly, there was no any abnormality and phytotoxic effect observed by spraying Brigade-BL on grapevines. Likewise, Brigade-BL was found compatible with Buprofezin 25 SC chemical insecticide.