Efficacy of Beauveria bassiana for control of the rice weevil Sitophilus oryzae (L.) (Coleoptera: Curculionidae)

Abstract

An entomopathogenic fungus, Beauveria bassiana was tested against the rice weevil Sitophilus oryzae. Bioassays were conducted by introducing 25 adult insects on 50 g of B. bassiana mixed rice in glass jars maintained at 28±2°C, and 70% RH. Mortality was monitored at five-day intervals until 25 days. At higher doses (7.6 log conidia/ml), B. bassiana produced a higher percentage of mortality up to 75.8% and F₁ adult emergence was reduced by 86.2%. At lower concentrations B. bassiana was not effective against S. oryzae. The study stresses the need for higher numbers of conidial inoculation for maximum mortality.