Eficácia de uma formulação contendo diclorvós e clorfenvinfós sobre Rhipicephalus microplus em condições de campo

Abstract

The aim of this study was to evaluate the in vivo efficacy of a commercial acaricide formulation containing an association of organophosphates (dichlorvos and chlorfenvinphos), administered topically, by spraying, in adult cattle naturally infested with Rhipicephalus microplus. For this, cattle naturally infested and without previous contact with acaricides were used. For group selection, engorged females measuring between 4.5 and 8.0 mm in length were counted on days -7, -4 and -1. Animals that had a count of more than 20 ticks were selected for the study. The animals were divided into two groups: the treated group and the control group, both composed of 10 animals, with similar tick infestation. In the control group, the animals were sprayed with drinking water, with 1 liter of water for each 100 kg of the animal, while in the treated group, the animals were sprayed with an acaricide association containing chlorfenvinphos and dichlorvos at a concentration of 600 mg/mL, obeying the same dose, 1 liter of the formulation for each 100 kg of the animal. Tick counts were performed by individually inspecting each animal every 7 days for 28 days. The counts were performed with the animals contained in a containment trunk, verifying the number of ticks present on the left side of the cattle. As a result, it was found that the association of chlorfenvinphos with dichlorvos was effective between 96.6% and 85.1%, reaching an average of 92.3%. Therefore, the commercial acaricide formulation containing dichlorvos and chlorfenvinphos administered by means of spraying is effective in vivo for controlling infestation by R. microplus in cattle in the recôncavo region of Bahia.