Evaluation of two species of entomopathogenic fungi against white grub, Holotrichia consanguinea (Blanchard) infesting potato in Maharashtra, India

摘要

The efficacy of two entomopathogenic fungi, Metarhizium anisopliae andBeauveria bassiana, against white grub, Holotrichia consanguinea infesting potato crop was studied under laboratory and field conditions. The estimated LC_(50) of M. anisopliae andB. bassiana towards third instar larvae of H. consanguinea were 5.76 x 10~5 and 7.50 x 10~5 conidia ml~(-1), respectively. The LT_(50) of M. anisopliae and B. bassiana at the concentration of 8 x 10s conidia ml~(-1) against third instar larvae of H. consanguinea were 4.88 and 6.73 days, respectively. In field experiments, M. anisopliae @ 2 x 10~(12) conidia ha~(-1) was found to be effective with an average efficacy of 46.74%, while it was 41.32% in phorate 10G @ 25kg ha~(-1). The maximum mycosis was recorded with the use of M. anisopliae (44.44%). The tuber infestation was statistically lowest (6.91%) and yield of marketable tubers highest (27.6t ha~(-1)) with the use of M. anisopliae as against 27.85% and 17.8t ha~(-1) in untreated plot, respectively.