Virulence of Native Isolates of Metarhizium anisopliae and Beauveria bassiana Against Helicoverpa armigera in Nepal

Abstract

The native isolates of entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana, were evaluated against the third instar larvae of the chickpea pod borer, Helicoverpa armigera, for mortality, infection rate and LT50 under laboratory conditions in Nepal. Out of four isolates of M. anisopliae and two isolates of B. bassiana evaluated, M. anisopliae M1 and B. bassiana B3, were the most virulent ones of all isolates evaluated, with a concentration at 10^7 conidia/ml. The M1 and B3 isolates had the highest mortality rates and required the shortest time to kill the larvae of H. armigera. After treatment with M1 and B1 isolates for 10 days, the larval mortality exceeded 85%. These data lay the ground work for further studies in optimizing the effectiveness of indigenous virulent isolates, M. anisopliae M1 and B. bassiana B3 against H. armigera in Nepal.