Effects of carbon and nitrogen sources and ratio on the germination, growth and sporulation characteristics of Metarhizium anisopliae and Beauveria bassiana isolates.

Abstract

The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana are ubiquitous and widespread with well documented broad-spectrum myco-pesticidal effects. It has been reported that nutrient source is an integral determinant of growth and virulence of entomopathogenic fungi. Nutrient based studies also impart light towards the identification of most commendable media for laboratory assays as well as selection of the tolerant isolates. With such a perspective, an in-vitro study was undertaken to evaluate conidial germination, mycelial growth and spore yield of fourteen M. anisopliae and seventeen B. bassiana isolates and the effect of different carbon and nitrogen sources on these characteristics were studied. The different isolates showed significant variation with respect to the differing preference for the nutrient sources. From this study it was inferred that isolate UM2 (M. anisoplaie) and AB1 (B. bassiana) exhibited commendable growth potentials on almost all the nutrient sources studied, and were basically more robust isolates and holds high affirmations for commercial usage as biopesticides.   Key words: Metarhizium anisopliae, nutrition, germination, growth, sporulation,Beauveria bassiana.