Avaliação do efeito acaricida do óleo resina de copaíba (Copaifera reticulata) e do extrato etanólico do resíduo da andiroba (Carapa guianensis) sobre o carrapato Dermacentor nitens

Abstract

The Dermacentor nitens tick is one of the main parasites of equine herds and is known as the horse-ear tick, which can cause diseases such as babesiosis. Differents groups of ixodicides commercial have been employed for the control these mite, however, the constant use of these products favors the emergence of resistant populations. Thus, the objective was to analyze the efficacy in vitro of copaiba resin oil and ethanolic extract of andiroba residue in different concentrations about larvae of D. nitens. The effects of concentrations 10, 5 and 2.5% of the solutions were evaluated, together with the control with Tween 80 (1%). The larval immersion test (TIL) was performed, in which approximately 100 larvae were immersed for 5 minutes in the test solutions and incubated in a biochemical oxygen demand oven for 24 hours under controlled conditions of temperature and humidity. The mortality calculation, according to the Abbott formula, revealed lethality rates for copaiba resin oil of 92.25, 87.07 and 85.93% for concentrations 10, 5 and 2.5%, respectively. The ethanolic extract of andiroba residue, in turn, showed mortality averages of 96.57, 82.01 and 76.29% for concentrations 10, 5 and 2.5%, in that order. At concentrations of 5 and 2.5%, both natural products tested showed mortality above 75%, being considered promising as potential acaricide products for this important tick species. Additional studies are needed to evaluate the in vivo efficacy of these natural products in the control of D. nitens. This is a pioneering work in tests using such products on equine tick larvae.