The Combined Effect of the Association of Extractives from Schinus lentiscifolius on the Fungus Beauveria bassiana Against the Tick Rhipicephalus microplus

Abstract

The cattle tick Rhipicephalus microplus causes substantial economic losses worldwide and has developed resistance to several synthetic acaricides. Therefore, the search for sustainable alternatives for tick control has intensified. Plant-derived compounds and entomopathogenic fungi, such as Beauveria bassiana, represent promising candidates for integrated control strategies. This study evaluated the in vitro effects of Schinus lentiscifolius extracts of different polarities, used alone or in combination with B. bassiana, against different developmental stages of R. microplus. The activity of the plant extracts, fungal conidia, and their combinations was assessed using adult immersion, larval packet, and larval immersion assays. The combined treatments increased larval mortality compared with the extracts used alone in both larval assays. In the larval packet and larval immersion assays, the crude ethanolic extract of S. lentiscifolius combined with B. bassiana achieved 100% mortality at 20 mg/mL. However, the effects observed against engorged females were limited. These findings indicate that the combination of S. lentiscifolius extracts and B. bassiana has promising in vitro larvicidal activity against R. microplus. Further studies are needed to characterize the interaction between the agents and to evaluate their efficacy and safety under in vivo and field conditions.