Evaluation of the efficacy of fospirate-treated collars against the brown dog tick.

Experimental tick infestations on dogs were done to determine the initial kill and residual effectiveness of a 15% fospirate-treated plastic colar against the brown dog tick, Rhipicephalus sanguineus (Latreille). The mean initial kill, determined 4 days after collar application (day 4), was 56.4%. The mean residual effectiveness of fospirate collars on test days 18, 33, 45, 61, 74, 88, and 112 was 89.1, 77.4, 89.5, 78.6, 73.2, 69.0, and 55.0% control, respectively.