Screening of Acaricides for Control of One-Host Ticks, 1982

Larvae of Boophilus annulatus (Say), the cattle tick, and B. microplus (Canestrini), the southern cattle tick, in colony at the Cattle Fever Tick Research Laboratory, Falcon Heights, TX, and Anocentor nitens (Neumann), the tropical horse tick and Dermacentor albipictus (Packard), the winter tick, in colony at Kerrville, IX, are placed onto cattle. Engorged females that detacn naturally are tested. Usually candidate compounds (technical materials) are formulated as emulsifiable concentrates containing 25% active ingredient (AI), 65% xylene and 10% Triton X-100. Compounds not soluble in xylene are usually formulated (14.3% AI) in a 1:1 mixture of N-methyl-2-pyrrolidinone and the xylene, Triton X-100 combination. Commercial wettable powders or emulsifiable concentrates may be used. All formulations are mixed with water immediately before treatment. Acaricides are routinely tested at 1, 0.1, and 0.01% AI; the lesser concentrations are obtained by serial dilution of the 1% concentration. For treatment, ticks are washed, dried, sorted into groups of 10, weighed, and placed into 20-25 ml of acaricide, which is stirred vigorously for 30 sec and then poured through a screen that retains the ticks.