Bioassays for measuring the acaricides susceptibility of catlle tick Boophilus microplus (Canestrini, 1887) in São Paulo state, Brazil

Abstract

The susceptibility of Boophilus microplus tick to acaricides was evaluated on farms located in different regions of Sao Paulo State. The method used for the evaluation was the immersion of engorged tick females in commercial formulation of the chemical groups organophosphate, pyrethroids, amitraz and the association between organophosphate and pyrethroid. The efficacy of pyrethroid acaricides was lower than 50% in all regions studied. The association between the organophosphate and pyrethroid had the mean efficacy higher than 90% in the North Region, and the amitraz had efficacy higher than 90% in the Northwest and Southern Regions. This work shows the low efficacy of pirethroids acaricides on Boophilus microplus in Sao Paulo State nowadays