Beauveria bassiana: Synergistic effect with acaricides against the tick Hyalomma anatolicum anatolicum (Acari: Ixodidae)

The results of this study showed that the high mortality rates against ticks can be achieved when the entomopathogen was combined with different concentrations of deltamethrin. In contrast, neither B. bassiana AT17 nor deltamethrin alone at the same condition could cause the higher mortality than that could be done by the mixture, in addition the mixture needs less time (shorten by three to five days) to kill the ticks comparatively as shown in the table below. Table Mortality rates of H. anatolicum anatolicum treated with deltamethrin and B. bassiana. [Display omitted] ► Combination of B. bassiana and acaricides was first used for control H. anatolicum anatolicum. ► The Combination in optimal proportions was highly effective in killing the ticks. ► The combination could reduce the concentrations of B. bassiana and acaricides. Owing to the need to combat the spread of chemical acaricide resistance in ticks, we evaluated the efficacy of a mixture of the entomopathogenic fungus Beauveria bassiana AT17 and acaricides for the control of Hyalomma anatolicum anatolicum in China. A mixture of B. bassiana AT17 at the concentration of 108conidia/mL and the synthetic pyrethroid deltamethrin at concentrations of 2500, 250, 25, 5, 2.5, 0.5 and 0.25ppm was tested in vitro. The germination capability, vegetative growth, conidia production, and viability of B. bassiana AT17 were assessed and the efficacy of the mixture in killing engorged H. anatolicum anatolicum females was measured. High mortality rates were achieved when the entomopathogen was combined with different concentrations of deltamethrin. Neither B. bassiana AT17 nor deltamethrin alone at the same concentrations could cause the higher mortality rates seen with the combination. In addition the combination killed the ticks more rapidly than did either agent alone (3–5days more rapidly). Our results indicate that the mixture of B. bassiana AT17 and deltamethrin has potential as a new type of reagent for integrated control of H. anatolicum anatolicum.