Efficacy of entomopathogenic fungi on mustard aphid

Two entomopathogens, Verticillium lecanii and Beauveria bassiana against Lipaphis erysimi on mustard crop. In laboratory, bioassay studies were conducted to determine the LC50 and LT50 values of these entomopathogens against L. erysimi. The cumulative corrected mortality of L. erysimi due to V. lecanii ranged from 47.50 ¿ 73.75 per cent at 7 days after treatment (DAT) whereas, due to B. bassiana it was 41.25 ¿ 66.25 per cent under laboratory conditions. The LC50 values of V. lecanii and B. bassiana against L. erysimi were 2.7 x 106 and 2.4 x 107 spores/ml, respectively. The LT50 values of V. lecanii for different concentrations against L. erysimi ranged from 99.52 ¿ 187.82 hours where the lowest LT50 value of 99.52 hours was obtained for the concentration of 1x1010 spores/ml. The LT50 values of B. bassiana against L. erysimi ranged from 117.74 - 213.28 hours where the lowest LT50 value of 117.74 hours was obtained for the concentration 1x1010 spores/ml. Field studies were carried out to assess the bioefficacy of the entomopathogens against L. erysimi where, lab cultured V. lecanii with concentration of 2.7 x 106 spores/ml recorded a mortality of 69.86 per cent while the lab culture