Abstract:Effects of a strain of entomopathogenic fungus Beauveria bassiana, Bb0062 on parasitic behavior of aphid parasitoid Aphidius gifuensis was evaluated in laboratory. The bioassay indicated that B.bassiana had high virulence on A.gifuensis, and LT50s of the parasitoid shorted with increasing conidia doses sprayed. The aphid sprayed fungus or 0.05% Tween-80 was used to rear A.gifuensis and results showed that parasitic rate of the parasitoid to healthy aphid (52.54%) was significantly higher than that to aphid sprayed fungus (40.19%), which suggested that the fungus could influence the parasitic behavior of the parasitoid by infecting its host aphid. On 0, 1, 3, and 5 days after fungus exposure, the parasitic rate of A.gifuensis adults was decreased by 21.0%, 17.2%, 33.3% and 30.4%, and parasitic time of the parasitoid was shorted by 35.9%, 38.7%, 53.1% and 39.7% compared to the control, respectively. Based on these results, it suggested that B.bassiana has adverse effect on parasitic behavior of parasitoid A.gifuensis.