PATHOGENICITY OF BEAUVERIA BASSIANA (BALSAMO) VUILLEMIN ISOLATE MZ674187 AGAINST TWO SPOTTED SPIDER MITE, TETRANYCHUS URTICAE KOCHAbarna, V.P., Vishnupriya, R., Sathiah, N. and Sendhilvel, V.Abstract The two spotted spider mite, Tetranychus urticae Koch is a polyphagous pest causing severe yield loss to an extent of 50 per cent in vegetables. The management of two spotted spider mite mostly rely on acaricides. The continuous use of acaricides resulted in rapid development of resistance in mites. In this study, an investigation was made to assess the pathogenicity of the Beauveria bassiana isolate (MZ674187) against two spotted spider mites. The pathogenicity of the isolate was assessed by treating the two spotted spider mite with different conidial load of B. bassiana MZ674187 ranging from 1 x 103 to 1 x 109 conidia/ml in laboratory conditions. Mortality of the mites were observed at 24 hours interval and the results indicate that the mite mortality increased when the conidia concentration was increased. The mortality of the mites was in the range of 14.4 per cent to 82.22 percent at the conidial load of 1 x 103conidia/ml and 1 x 109 conidia/ml respectively at 9th day after inoculation. The median lethal dose and median lethal time were calculated and was found to be 1.55 x106 conidia/ml and 111.01 hours respectively. |