Control of subterranean termite Coptotermes Curvignathus (Isoptera: Rhinotermitidae) by entomopathogen Metarhizium anisopliae var. anisopliae cultured in liquid state fermentation

Abstract

Solid state fermentation has been used for mass production of Metarhizium anisopliaemany years ago. However, solid state fermentation was time consuming, costly and unable to produce in large amount. We examined the suitability of liquid state fermentation to mass produce M. anisopliae and the effect of culture medium on fungal pathogenicity. Three different liquid medium selected for this study was Jenkins medium, Leland medium and MPOB medium. The fungus was cultured for 5 days to examine the growth rate. Yield of submerged conidia in different medium was assessed on day 3. Fungal virulence was bioassayed on termite Coptotermes curvignathus. The results indicated that Jenkins medium yielded significantly lower growth rate and dry weight (1.472 mg mL−1), but the fungus exhibited highest virulence (100% mortality on day 4) among the 3 medium studied. MPOB medium had the highest growth rate and DW yield (1.961 mg mL−1) but achieved 100% mortality only on day 6. The LC50 result showed Jenkins medium yielded the most virulent fungus culture compared to Leland medium and MPOB medium.