Veterinarija ir Zootechnika

The deficiency of tick control causes large economic losses for the health of animals and the risk of transmission of zoonotic diseases. Their control is based on the use of acaricides such as organophosphates, synthetic pyrethroids, amidines and macrocyclic lactones; however, its inappropriate use has favoured the presence of populations resistant to the main families of acaricides. This study was conducted with the objective to evaluate the resistance of Rhipicephalus (Boophilus) microplus against three widely used ixoidicides in Nicaragua, namely coumaphos, amitraz and cypermethrin, applied in the concentrations indicated by the manufacturer. For this, the techniques of Adult Immersion Test (AIT) and Larval Package Test (LPT) were applied, for which ticks were collected from farms in Western Nicaragua. The results obtained through the AIT show that coumaphos has a higher percentage of oviposition inhibition of 86%, while cypermethrin only demonstrated an oviposition of 12.9%. Mortality in adults treated with coumaphos was 97.72%, and in those treated with amitraz it was 48.8%, while cypermethrin only provided a mortality of 14.71%. In this study, the Rhipicephalus (Boophilus) microplus ticks collected from cattle were determined to have elevated levels of resistance to cypermethrin but low resistance to coumaphos.