In vitro evaluation of the acaricidal potential of Beauveria bassiana DS3.17 on the common tick (Rhipicephalus microplus) in Oaxaca, Mexico

Abstract

The tick Rhipicephalus microplus causes damage to cattle farming, has a great economic impact, and significantly influences the productivity and commercial competitiveness of the sector, mainly in tropical and subtropical areas of the country, generating annual losses of millions. Currently, the control of the ectoparasite using biological agents (mainly entomopathogenic fungi) has a high potential to reduce tick populations. The objective of the present study was to evaluate in vitro the acaricidal potential of Beauveria bassiana DS3.17 on engorged R. microplus females, by immersion of the mite in different concentrations of conidia of the fungus to determine the effects on reproductive parameters (total egg weight, hatching percentage, oviposition and nutrition indices). The evaluated concentrations of B. bassiana DS3.17 showed an acaricidal effect of up to 93.2 % in adults and a change in the behavior of the biological parameters of adult females, inhibiting oviposition between 75.84 and 79.60 %. As for the estimated reproduction index, a control of 45.23 to 83.79 % was obtained, the nutrition index was 10.21 and 10.67 %. The study showed a change in the behavior of reproductive parameters when B. bassiana DS3.17 was used, and each of the results showed significant differences; the concentrations of conidia affected the reproduction of the parasite with respect to the control, therefore, B. bassiana DS3.17 presented an acaricidal potential for the control of the tick.