Acaricidal activity of eugenol on Rhipicephalus microplus (Acari: Ixodidae) and Dermacentor nitens (Acari: Ixodidae) larvae.

The aim of this study was to evaluate the acaricidal activity of eugenol, with different solubilizations and concentrations, on Rhipicephalus microplus and Dermacentor nitens larvae and to determine the lethal time. The study consisted of four experiments, and the mortality was assessed using the larval packet test with adaptations. The mortality observed in the first experiment was 100 % for all the groups treated with eugenol solubilized in different solvents. In the second, the hydroethanolic formulation of eugenol was used, and the mortality rates for R. microplus and D. nitens was 100 % starting from the concentration of 5.0 μl/ml. In the third experiment, the mortality was 100 % for larvae of both R. microplus and D. nitens after 1 h of contact. And in the fourth experiment, the mortality was above 90 % and statistically similar (p > 0.05) for the four methods the test evaluated.