Four kinds of entomopathogenic fungi, Beauveria bassiana, Paecilomyces fumosaroseus, P. farinosus and Metarhizium anisopliae, were used to infect Myzus persicae and Aphidius gifuensis by ways of immersing the target insects in spore suspension and spraying them with spore powder. Mortalities of M. persicae infected for 8 d by the four fungi were 100%, 78.00% - 95.00%, 90.00% and 66.67%, respectively, which were remarkably higher than that of the control group (1.67% - 3.33%); and mortalities of A. gifuensis attacked for 3 d by the same four fungi were 79.67% - 80.33%, 20.00% - 26.67%, 46.67%, and 26.67% - 60.00%, respectively. Infection by P. fumosaroseus resulted in the same mortality with the control group, and P. fumosaroseus was chosen as the potential fungus to be carried by the wasp for infection of aphids. Three ways: immersing parasitized aphids by spore suspension, spraying parasitized aphids with spore powder and forcing female wasps to creep over spore powder f! or infection, were employed to make female bees convey the fungus. The three ways had little impact activities of the female wasps. The number of spores (0.755 x 108 - 0.785 x 108) carried by each wasp in the former two ways, however, was much lower than in the last way (4.535 x 108 - 5.293 x 108). Further test revealed that infecting A. gifuensis with fungi could result in aphid mortality of 86.0% in the laboratory, which represents an increase of 24.3% as compared with that of non-fungi-carrying wasps. Aphidius gifuensis (Aphidiidae). Aphidius gifuensis: Biological control, Control potential, Fungal diseases, Beauveria bassiana, Metarhizium anisopliae, Paecilomyces farinosus, Paecilomyces fumosaroseus. Arthropods; Hymenopterans; Insects; Invertebrates. none