Acaricide evaluation of natural derivatives of Achyrocline satureioides and Schinus lentiscifolius in association with biotechnological products obtained from entomopathogenic fungi on the bovine tick Rhipicephalus (Boophilus) microplus

Abstract

Despite the prominence and social and commercial importance of bovine breeding, infestations by ectoparasites, mainly by the tick Rhipicephalus (Boophilus) microplus, present a great economic impediment. Control is currently carried out using synthetic carrapaticides and its indiscriminate use has contributed to the emergence of resistance of the parasites most of the molecules available. Thus effective, economically viable and potentially safe alternatives should be investigated, such as the use of natural derivatives associated with entomopathogenic fungi. This project is part of the PhD student Rafaela Regina Fantatto and aims to evaluate plant extracts of Achyrocline satureioides and Schinus lentiscifolius associated with the entomopathogenic fungus Beauveria bassiana, as well as the enzyme chitinase produced by it, on different stages of the life cycle of the bovine tick R. (B.) microplus. Plant extracts will be phytochemically characterized by spectrometric and liquid chromatography techniques. The enzyme chitinase will be produced by B. bassiana fungus in liquid fermentation submerged in orbital shaker. Carrapaticidal activity of plant extracts, fungus, chitinase and associations thereof will be analyzed by in vitro tests such as immersion test of engorged females, impregnated paper contact test and larval immersion test. Preliminary studies have shown that crude ethanol extracts from A. satureioides and S. lentiscifolius do not inhibit B. bassiana at the concentration of 1.25 mg/ml, a promising result that allows the association tests proposed in this project. (AU)