STUDIES ON THE EFFICACY OF SOME COMMONLY USED ACARICIDES

The evaluation of three commonly used acaricides was conducted against the cattle tick Boophilus microplus and the dog tick Rhipicephalus sanguineus. The commonly used synthetic pyrethroids, cypermethrin and deltamethrin (0.05, 0.1 and 0.2% concentrations) and a formamidine compound amitraz (0.1, 0.2 and 0.3% concentrations) were tested against different stages of the cattle tick and the dog tick. The tea bag method was used in the study with all stages of ticks, filter paper impregnation method was used against adult male ticks and larvae and immersion method was used against larvae and adult engorged female ticks. The FAO recommended adult immersion test with discriminating doses (AIT-DD) was carried out to know the resistance development if any. Among the acaricides used amitraz was found to be more effective followed by deltamethrin and then cypermethrin. Amitraz has not shown any resistance to both the species of ticks used in the present study. Among the three in vitro tests used to evaluate efficacy of acaricide, the immersion method fared better in efficacy followed by the tea bag method and filter paper impregnation method.