In vitro effect of seven essential oils on the reproduction of the cattle tick Rhipicephalus microplus

Abstract

The acaricidal effect of seven essential oils was examined <i>in vitro</i> against the cattle tick (<i>Rhipicephalus microplus</i>). Engorged female ticks were manually collected in farms of Southern Brazil and placed into petri dishes (<i>n</i> = 10) in order to test the following oils: juniper (<i>Juniperus communis</i>), palmarosa (<i>Cymbopogon martinii</i>), cedar (<i>Cedrus atlantica</i>), lemon grass (<i>Cymbopogon citratus</i>), ginger (<i>Zingiber officinale</i>), geranium (<i>Pelargonium graveolens</i>) and bergamot (<i>Citrus aurantium var bergamia</i>) at concentrations of 1%, 5%, and 10% each. A control group was used to validate the tests containing Triton X-100 only. Treatment effectiveness was measured considering inhibition of tick oviposition (partial or total), egg's weight, and hatchability. <i>C. martinii</i>, <i>C. citratus</i> and <i>C. atlantica</i> essential oils showed efficacy higher than 99% at all concentrations tested. In addition, <i>J. communis</i>, <i>Z. officinale</i>, <i>P. graveolens</i>, and <i>C. aurantium var bergamia</i> oils showed efficiency ranging from 73% to 95%, depending on the concentration tested, where higher concentrations showed greater efficacy. It was concluded that essential oils can affect tick reproduction <i>in vitro</i> by inhibiting oviposition and hatchability.