Abstract:In order to select some high pathogenicity strains in the entomogenous fungi as biological control agent against Carposina sasakii (Matsumura), a destructive pest in fruit orchards, the five fungal strains in three species were studied. The five strains were originally isolated from the natural diseased larvae of C.sasakii infesting in Shanxi Province, China. Their virulence was evaluated by comparing the diseased symptom, infected insect mortality, and the activities of the subtilisin-like protease, chitinase, and lipase of the strains. The results showed significant difference in the host insect‘s diseased symptom and mortality among the five different strains. After 10 days post infected, the highest host mortality 89.3% were found in the experimental section of the strain Beauveria bassiana BbTST05, and meanwhile, the activities of subtilisin-like protease, chitinase, and lipase of the strain all were the highest in the five strains. Thus, it was the highest virulence strain against C.sasakii. The strain Isaria farinosa IfTSL02 caused higher host mortality and showed higher activities of subtilisin-like protease and chitinase. However, the host mortalities caused by the three strains FoTSL01, FoTSL03, and FoTSL04 of Fusarium oxysporum were all below 61%, and the activities of the three extracellular enzymes of these three strains were lower. Therefore, the two strains BbTST05 and IfTSL02 could be used to control C.sasakii.