The relative efficacy of 25 acaricides, applied topically to the engorged adults of B. microplus was in the following order: chlorfenvinphos > tetrachlorvinphos > dimethoate > chlorpyrifos > fenitrothion > dicrotophos (LC50 = 0.000897−0.00244%) > naled > propoxur > crotoxyphos > pirimiphos ethyl > coumaphos > dioxathion (LC50 = 0.00425−0.00534%) > trichlorphon > lindane > carbaryl > allyxycarb > diazinon (LC50 = 0.00737−0.0149%) > promecarb > ethion > chlorpyriphos methyl > chlormebuform (LC50 = 0.021−0.0593%) > clenpyrin > chlordimeform > pirimiphos methyl > phosphamidon (LC50 = 0.1566™0.275%).
The order of toxicity is different from their relative efficacy against the larvae of the same population of the tick. Applied implications of the results are discussed.