Pathogenicity of entomopathogenic fungus Beauveria bassiana against orchid weevil Orchidophilus aterrimus (Coleoptera: Curculionidae)

Orchidophilus aterrimus is one important insect pest of orchids in Indonesia, and its management typically requires intense insecticide use. The utilization of entomopathogenic fungi such as Beauveria bassiana is a promising component of integrated pest control for order Coleoptera. This study aimed to evaluate the pathogenicity of the entomopathogenic fungus B. bassiana to control O. aterrimus in orchids. The research was conducted at the Laboratory of Entomology of the Indonesian Ornamental Crops Research Institute. The study used a completely randomized design with four replications. The treatments of conidia density of B. bassiana was 0 (as a control), 105, 106, 107, 108, and 109 conidia per mL, respectively. The application method was direct contact. The results showed that B. bassiana could infect the adult weevil. The highest mortality (86.9%) and fastest mortality time (4 days) were found at a conidia density of 109. The efficacy of B. bassiana generally increased at higher conidia concentrations. LC50 and LC95 values for weevil adults mortality were 1.6 x 107 and 2.17 x 1010 conidia/mL. The findings of this study indicated that the entomopathogenic fungus B. bassiana has significant potential for controlling O. aterrimus and should be developed into a biological pesticide as a part of the integrated orchid pest control program.