In vitro efficacy of Carapa guianensis Aublet (Meliaceae) oil on Damalinia (Bovicola) ovis Schrank (1781)

Abstract

Productivity in small ruminants can be compromised due to lice infestations. This pest infestation is controlled by the administration of insecticides, and their excessive use causes resistance. New control alternatives are being investigated, especially the use of phytotherapeutics. Research using the oil from Carapa guianensis (andiroba) has shown insecticidal action on feline and goat lice specimens. The present study aimed to evaluate the efficacy of C. guianensis seed oil, in vitro, on Damalinia (Bovicola) ovis. Nine hundred specimens of D. (Bovicola) ovis were randomly assigned into groups and were subjected to different treatments: (G1) 1,000 to 15.6 mg/mL of C. guianensis oil; (G2) 3% Tween 80 (negative control); and (G3) amitraz 1.25 g/mL (positive control). Data presentation was expressed as mean efficacy ± standard deviation using the statistical program SPSS version 23.0 and statistical differences of the experimental groups were obtained by Kruskal-Wallis and Friedman. Probit Regression was performed to obtain CI₅₀ and CI₉₀, with a significance level of p < 0.05. The oil with a concentration of 1,000 mg/mL had an efficacy of 94% after 24 hours of exposure, differing statistically from the positive and negative control (p < 0.05). The IC₅₀ and IC₉₀ values were 439.21 mg/mL and 807.09 mg/mL, respectively. The action of the oil on the specimens was independent whether it was an adult female, male, or nymph. It is concluded that C. guianensis oil showed in vitro insecticidal effect against D. (Bovicola) ovis.