Susceptibility of the brown dog tick (Acari: Ixodidae) to fresh residues of acaricides: laboratory assays and comparison of susceptibility of different life stages of the lone star and American dog tick.

Abstract

Five- to 7-week-old nymphs of the brown dog tick, Rhipicephalus sanguineus (Latreille), were exposed for 22 to 24 h to residues of acetone dilutions of 27 technical acaricides on disposable glass pipettes. Effectiveness of the compounds in killing ticks ranged from an LC50 of 0.000026% for propoxur to an LC50 of 0.053% for chlordane. The relative susceptibility (LC50) of the life stages of the brown dog tick, American dog tick, Dermacentor variabilis (Say), and the lone star tick, Amblyomma americanum (L.), to four acaricides was: larvae > nymphs > adults. Each analogous stage of the brown dog tick was generally more susceptible to permethrin, diazinon, and carbary1 than the same stage of the American dog tick or the lone star tick. Brown dog ticks were less susceptible to lindane, however, indicating the need for field data on each species in control programs in which acaricides are used.