In vitro acaricidal activity of ocimum gratissimum essential oil on rhipicephalus sanguineus, amblyomma sculptum and rhipicephalus microplus larvae

Abstract

The essential oil use for veterinary ectoparasites control may be an excellent alternative to synthetic compounds marketed, as a way to reduce negative impacts on human health, and the environment. The incidence of different tick species in different locations is a result of the environmental characteristics of the national territory. Among the veterinary interest species are Amblyomma sculptum, Rhipicephalus microplus and Rhipicephalus sanguineus. Ocimum sp essential oils (EOs) exhibit a range of biological activities such as insecticide, acaricide and insect repellency. The aim of this study was to evaluate in vitro activity and establish the LC50 of Ocimum gratissimum EO against A. sculptum, R. microplus and R. sanguineus larvae in order to explore the potential use of this essential oil in tick control. The bioassay results showed that O. gratissimum essential oil exhibited great acaricidal activity against all larvae tick tested in the evaluated concentration range. Larvicidal activity was more pronounced for R. microplus (LC50= 2.0 mg.mL-1) when compared to A. sculptum (LC50= 5.5 mg.mL-1) and R. sanguineus (LC50= 6.2 mg.mL-1). These results are promising for the development of herbal products to obtain an alternative method of controlling tick larvae while minimizing the use of synthetic products.