Beauveria bassiana (Balsamo) vuillemin (Strain ITCC-4668) as acaricide against Tetranychus urticae Koch (Acari: Tetranychidae)

The bioefficacy of entomopathogenic fungi Beauveria bassiana (strain ITCC-4668) was evaluated against two spotted spider mite Tetranychus urticae Koch under field conditions. Highest reduction in T. urticae population was recorded in B. bassiana (0.3× 10⁹ conidia ml⁻¹) treated plots (62.36%) followed by Ethion 50 EC (0.05%) (61.97%), B. bassiana at 0.3×10⁸(55.59%) (56.69%) and 0.3×10⁷ conidia ml⁻¹. A significant negative correlation was found between the average number of mites and chlorophyll content (r= -0.766). In uninfected leaves higher chlorophyll content was recorded (1.016 μg/ml) as compared to mite infested leaves (0.166 μg/ml). B. bassiana treatment improved the total chlorophyll content (0.346 μg/ml), chlorophyll a (0.079 μg/ml) and chlorophyll b content (0.267μg/ml).