Beauveria bassiana (Ascomycota: Hypocreales) is a fungus that grows naturally in soils throughout the world and acts as a parasite on various arthropod species, causing white muscardine disease and it is being used as a biological insecticide to control a number of pests. It can infect more than 700 species of arthropods and its use as microbial insecticides is a more appropriate approach to suppress pest population in the present scenario of integrated pest management. This potential pathogen is mass produced and marketed as various formulations. In this context, a field experiment was conducted to investigate the effective dosage of Beauveria bassiana against rice leaf folder, Cnaphalocrocis medinalis Guenee (Lepidoptera: Pyralidae) under normal field conditions. Among the dosages tested, increased dose of Beauveria bassiana 1.15% w/w had caused higher mortality of larval population of Cnaphalocrocis medinalis and less infestation percentage of rice plants. The grain yield was observed higher in the plot treated with Beauveria bassiana 1.15% w/w @ 3 kg/ha than other treatments. Hence, Beauveria bassiana 1.15% w/w @ 3 kg/ha can be recommended to control the rice leaf folder Cnapholocrocis medinalis in the rice field for effective management.
