Bioefficacy of Metarhizium anisopliae (Metchnikoff) Sorokin on Cowpea Aphid (Aphis crassivora Koch)

Laboratory bioassay studies were carried with nine different conidial concentrations of Metarhizium anisopliae (Metchnikoff) Sorokin ranging from 1×103 to 1×1011 conidia/ml against the adults of Aphis craccivora Koch. Mortality of the aphid was monitored at 24 h (1day) interval up to five days. The data of corrected per cent mortality at different time intervals indicated that the mortality of the aphid increased with increase in time interval. In the highest concentration (1011conidia/ml) 83.83% mortality was obtained. This was followed by a mortality of 64.72 and 52.96% in the conidial concentration of 1×1010 conidia/ml and 1×109conidia/ml. However, mortality of the treated aphid declined with decrease in concentrations with a lowest mortality of 17.65% at 1×103conidia/ml. The result from the present study showed that M. anisopliae can be used as a promising bio control agent for the management of A. craccivora.