Pathogenicity of Beauveria Bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae) and Crude Secondary Metabolites against Dendroctonus Micans (Kugelann,1974) (Coleoptera: Curculionidae)

Abstract

Beauveria bassiana (Balsamo-Vuillemin, 1912) (Hypocreales: Clavicipitaceae) is a valuable source of natural bioactive compounds, particularly secondary metabolites. This study, conducted in 2024 at Trabzon Forest Pests and Biological Control Laboratory, aimed to evaluate the insecticidal efficacy of a crude ethyl acetate extract of its secondary metabolites against Dendroctonus micans (Kugelann, 1794) (Coleoptera: Curculionidae) larvae and its antimicrobial activities. Pa-4 strain caused 100% mortality of D. micans larvae within ten days of 1 x 10(9) spores/mL, and the LC50 value was determined to be 1.63 x 10(5) spores/mL. The crude secondary metabolites extract concentration was 0.065 g/mL in the biomass and insoluble residues (mycelial extract) and 0.68 g/mL in the supernatant. The LC50 value for micelle-extract was 1019 ppm, while for the supernatant extract it was 1382 ppm (p<0.05). The antimicrobial activity of the crude secondary metabolites mycelial extract exhibited the largest zone of inhibition against Enterococcus faecalis ATCC 51299, with a diameter of 9.73 mm, followed by Bacillus subtilis ATCC 6633 (9.28 mm), and Candida albicans ATCC 10351 (6.94 mm) (p<0.001). This study suggests that the Pa-4 strain and crude secondary metabolites extract could be potential agents for the biological control of D. micans and antimicrobial properties.