Chiang Mai Journal of Science

The activities of six entomopathogenic fungal isolates, collected from naturally infected insects, were tested against fruit fly Bactrocera spp. pupa (Diptera: Tephritidae) and evaluated in vitro with different conidial concentrations. All tested isolates were pathogenic to fruit fly pupa. According to the 50% lethal concentration, Metarhizium flavoviride CMUCDCT01, Paecilomyces lilacinus CMUCDMT02 and Beauveria bassiana CMUCDMF03 had the highest pathogenicity at the conidial concentration of (1×10⁸ spore ml^-1). Mortality of pupa varied from 25.89% to 100% in M. flavoviride, 22.22 to 100% in P. lilacinus and 29.67% to 100% in B. bassiana. In soil bioassays, pupal mortality was not significantly different between drenching and premixing the conidial suspension with soil. However, the mycelia structure of fungal isolate CMUCDMF03 was recorded in premixing of the conidial solution with soil. According to our investigation of antimicrobial activity of fungal isolates, certain isolates produce antibacterial and antifungal activity in different cultured media without the addition of insect-derived materials.