Evaluation of different adjuvants was conducted during 1991 and 1992 seasons. Field application of M. separata NPV @ 500 LE/ha along with jaggery 0.5 per cent, boric acid 0.1 per cent, buttermilk 1.0 per cent, boric acid 0.3 per cent and wholemilk 0.5 per cent registered 63.4, 65.9, 57.4 and 53.7 per cent larval mortality as against 13.9 per cent when NPV was applied alone, indicating that efficacy of the virus can be significantly increased by the addition of one of these adjuvants.