Effect of relative humidity on the efficacy of entomopathogen Beauveria bassiana-based mycopesticide against red spider mite Tetranychus macfarlanei

Tetranychus macfarlanei is a potential threat to various economically important crops. Chemical control widely used this spider mite, but the exclusive reliance on chemical acaricides now being questioned, and entomopathogens are emerging as promising alternative. The efficacy of largely depends abiotic factors like temperature, humidity, rainfall etc. experiments were conducted determine effect relative humidity entomopathogen Beauveria bassiana (strain GHA), marketed BotaniGard ES, against adult female egg stages T. under laboratory conditions. Adult females eggs treated with three concentrations (1×106, 1×107, 1×108 conidia/ml), virulence was assessed mites held at levels (55, 75, 95 ± 2% RH) 25 1 °C. results showed that mortalities dose-dependent, there certainly synergistic efficacy. When above conditions, highest 86.4 91% recorded concentration conidia/mL 75 RH, respectively, after six days treatment. LT50 values 28.7 h 33.4 RH in conidia/ml, which significantly lower than for other levels. This study identified conidia/ml B. best possible combination manage mite.