IntroductionBeauveria spp. andDastarcus helophoroidesFairmaire adults were simultaneously released to attack elder larvae or pupae ofMonochamus alternatusin pine forests in China. However, little is known about the pathogenicity virulence and biosafety ofBeauveriaspp. on beneficial adults ofD. helophoroides, and specificBeauveria bassiana(Bb) strains should be selected for synthetic release together withD. helophoroides.MethodsA total of 17 strains ofBeauveriaspp. were collected, isolated, and purified, and then their mortality, cadaver rate, LT50, spore production, spore germination rate, and growth rate ofD. helophoroideadults were calculated based on 0–20 days data after spore suspension and powder contact.Results and discussionThe lethality rate of BbMQ, BbFD, and BbMH-03 strains toD. helophoroidesexceeded 50%, and the cadaver rate reached 70.6%, among which the mortality rate (82.22%), cadaver rate (47.78%), spore production (1.32 × 109spores/ml), spore germination rate (94.71%), colony dimension (49.15 mm2), and LT50(10.62 d) of the BbMQ strain were significantly higher than those of other strains (P< 0.01), and the mortality ofD. helophoroidesadults increased significantly with increased spore suspension concentration, with the highest mortality reaching 92.22%. This strain was identified asBeauveria bassianaby morphological and molecular methods, while the BbWYS strain had a minimum lethality of only 5.56%, which was safer compared to other strains of adultD. helophoroide. Consequently, the biological characteristics and pathogenicity of differentBeauveria bassianastrains varied significantly in their effects onD. helophoroideadults, and the safety of different strains should be assessed when they are released or sprayed to control multiple pests in the forest. The BbMQ strain should not be simultaneously sprayed with releasingD. helophoroideadults in the same forest, while the BbWYS strain can be used in concert withD. helophoroideto synergize their effect.