Efficacy of fungal pathogen, Fusarium semitectum against sugarcane woolly aphid Ceratovacuna lanigera Zehntner under laboratory and greenhouse conditions was evaluated at the Department of Entomology, College of Agriculture, Shimoga during 2005-06. The results showed that earlier instars of woolly aphid are more susceptible to the fungus. Chlorpyriphos 20 EC (0.04%) was effective against woolly aphid even at 15 days after spray. The combination of F.semitectum and chlorpyriphos (0.02%) registered the highest mortality of 84.12 per cent followed by chlorpyriphos (0.04%) and F.semitectum 5.4 x 109 spores/ml and F.semitectum 2.7 X 109 spores/ml + nimbicidine  (0.03%) which registered 72.85 and 75.76 per cent mortality respectively under green house conditions.