AVALIAÇÃO IN VITRO DO ÓLEO DE Carapa guianensis AUBL. (ANDIROBA) NO CONTROLE DO CARRAPATO DO BOI Rhipicephalus (Boophillus) microplus

Abstract

The indiscriminate use has generated resistance in Rhipicephalus (Boophilus) microplus, causing negative environmental impacts and making it necessary to search for alternatives to synthetic acaricides. In this regard, the objective of this study was to evaluate the in vitro biological acaricidal effect of andiroba oil in combating R. microplus. The study was conducted at IF Goiano – Campus Campos Belos from August 2022 to July 2023, in the laboratories of Chemistry, Ecotoxicology, Forage Production, and Pastures, adopting a randomized block design with three blocks and a splitplot arrangement over time (4×12). The plots consisted of the incubation periods (24, 48, 72, and 96 hours), and the subplots were formed by the different concentrations of andiroba oil (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100% andiroba oil + control). Teleogynes of R. microplus were collected from naturally infested cattle of undefined breed, sex, and age, sourced from rural properties located in the vicinity of the municipalities of Campos Belos-GO and Combinado-TO. The cattle selected for collection had not been treated with any contact acaricide for at least 30 days and systemic acaricides for at least 45 days. Each experimental unit consisted of ten teleogynes arranged in Petri dishes. The lethal dose was determined as a function of the oil concentration levels and the in vitro incubation period, by applying 10 µL of the oil to the dorsal region of the teleogynes. The data were collected, tabulated, and analyzed using R Statistical software, subjected to analysis of variance and compared by the Scott Knott mean test, and subsequently analyzed by regression, both at a 5% significance level for these quantitative treatments. There was a significant interaction between the oil concentrations and the incubation periods (P < 0.05), with high mortality rates, especially from 72 hours of incubation onward. The results indicated critical dosage thresholds, with dosages below 30% being more effective, as they reduce production costs and also decrease selection pressure and the development of tick resistance.Ifgoiano grant received to carry out research.