ACARICIDAL ACTIVITY OF COMBINED COMMERCIAL STRAINS OF ENTOMOPATHOGENIC FUNGI AGAINST Amblyomma mixtum AND Rhipicephalus microplus TICKS

Abstract

<p>Background:<em> Rhipicephalus microplus</em> and <em>Amblyomma mixtum</em> are the most important tick species affecting livestock in tropical areas. They can have a direct harmful effect on cattle and humans due to transmission of pathogens of tick-borne diseases (TBD). Entomopathogenic fungi have an important role in crop pest control. However, data concerning the efficacy of use of entomopathogenic fungicombinations are scarce. <strong>Objective:</strong> For this reason, in this study, the efficacy of commercial fungal combinations was assessed: Trishok<sup>®</sup> (<em>Trichoderma </em><em>harzianaum </em>and <em>Trichoderma </em><em>virens</em>) and Esporomax<sup>® </sup>(<em>Beauveria bassiana</em>,<em> <em>Metarhizium anisopliae</em></em>, <em>Paecelomyces fumosoroseu</em>s). <strong>Methodology: </strong>Adult immersion tests were performed with six different concentrations of fungal solutions. Results: In<strong> </strong>this study, Trishok<sup>® </sup>and Esporomax<sup>® </sup>showed potential efficacy against <em>R. microplus</em>. Different concentrations of fungal application tested on <em>A. mixtum </em>did not show any effect. The observed mortality of <em>R.</em><em> microplus</em> was 85. 0 ± 2.0 and 65.0 ± 2.0 for Trishok<sup>®</sup> and Esporomax<sup>®</sup>, respectively. The estimated LC<sub>50</sub> for <em>R. microplus</em> immersed in solutions of Trishok<sup>®</sup> and Esporomax<sup>® </sup>thereof were: 6.5x10<sup>4 </sup>and3.9x10<sup>5 </sup>conidia mL<sup>-</sup><sup>1</sup>, respectively. <strong>Implications: </strong>These results should be considered in the design and implementation of alternatives based on the biological control of ticks. <strong>Conclusion</strong><strong>:</strong> We can conclude that combined commercial strains of entomopathogenic fungi have <em>in vitro</em> acaricidal activity against <em>R. microplus</em>. </p>