Effect of local strains of Beauveria bassiana (Bb024) and Metarhizium anisopliae (M7/2) against the fallweb worm Hyphantria cunea (Lepidoptera: Arctiidae) in Georgia

Abstract: The indigenous isolates of the entomopathogenic fungi Beauveria bassiana (Bb-024)and Metarhizium anisopliae (M7/2) against fifth to seventh instars larvae of Hyphantria cunea intwo concentrations of 1 x 107 and 1 x 108 conidia ml-1 were tested in the laboratory. Maximummortality of larvae was observed 4-9 d after treatment. Both isolates were pathogenic to H. cunealarvae. The mean mortality caused by B. bassiana ranged from 59.8% to 84.3% and that ofM. anisopliae ranged from 52% to 68%. The living larvae hidden under leaves and cordon madecocoons and transformed into pupae. The adult moths appeared from the overwintering pupae.They began to emerge massively and mated. The emergence of adults of B. bassiana was 69.6%,that of M. anisopliae was 60%, and that of the control was 55.7%. The larvae hatched 7 to 10 dlater (the hatching rates were: B. bassiana – 76.3%, M. anisopliae – 70%, control – 89.5%). Incase of B. bassiana treatment, dimorphic males emerged from pupae often showing undevelopedwings.