In vitro analysis of the action of acaricides on Boophilus microplus strains (Canestrini, 1887) taken from dairy cattle from northeast area of the São Paulo State

Abstract

The susceptibility of Boophilus microplus ticks to nine insecticides was evaluated in vitro through immersion test. The insecticides contained the following compounds: Alphamethrin + Dichlorvos, Amitraz, Cypermethrin, Cypermethrin + Chlorphenvinphos, Coumaphos, Deltamethrin, Dichlorvos + Cypermethrin, Dichlorvos + Chlorphenvinphos and Zetacypermethrin. Ticks were collected from dairy cows in 17 properties of the northeast of the Sao Paulo State. Only three formulations reached recommended effectiveness (³ 95,0%): Cypermethrin + Chlorphenvinphos in nine properties, with average 89,69% ± 15,49, Dichlorvos + Chlorphenvinphos in eight, with average 91,22% ± 11,50 and the Amitraz in seven, with 78,62% ± 24,47. The results did not differ significantly (P > 0,05) from each other.