Association of cypermethrin, dichlorvos and piperonyl butoxide against <i>Rhipicephalus (Boophilus) microplus</i> in naturally infested cattle

Abstract

This study evaluated the effectiveness of cypermethrin (5%) associated to dichlorvos (45%) and piperonylbutoxide (25%) against R. (B.) microplus in naturally infested cattle. Forty bovine females were selected,after three consecutive counts (days -3, -2 and -1) of engorged females of R. (B.) microplus, between 4.5and 8.0 mm in length, on the left side of each animal. For the average of these three counts, the animalswere randomized into four groups of 10 bovines each, on day zero, treated with topical administration(Spray) of this compound at a dose of 1:400 and 1:800 and the positive control group (cypermethrin 15% +chlorpirivos 25% + citronella 1%) at the dose of 1:800. To evaluate the treatment effectiveness were realizedfurther tick counts on days 3rd, 7th, 14th, 21st, 28th and 35th day post-treatment (DPT). It was found that thecombination of Cypermethrin, dichlorvos and piperonyl butoxide, for both studied doses, demonstratedeffectiveness with at least 95%, between the 3rd to 21st DPT, reducing significantly (P<0.01) the tick femalesnumber in the groups treated when they were compared to the control group, observed during all bioassay(35 days), representing an effective alternative in the chemotherapy control by the parasitism of thisixodidae.