In vitro activity of fipronil against different populations of Rhipicephalus Boophilus microplus (Acari: Ixodidae)
ABSTRACT. Cid Y.P., Magalhães V.S., Santos A.L., Florêncio C.N., Correia T.R. & Scott F.B. [In vitro activity of fipronil against different populations of Rhipicephalus Boophilus microplus (Acari: Ixodidae)]. Atividade in vitro do fipronil frente a diferentes populações de Rhiphicephalus Boophilus microplus (Acari: Ixodidae). Revista Brasileira de Medicina Veterinária, 34(Supl. 1):5-10, 2012. Universidade Federal Rural do Rio de Janeiro, Instituto de Veterinária, Seropédica, RJ 23890-000, Brasil. E-mail: firstname.lastname@example.org Laboratory tests were performed to evaluate activity of fipronil formulated as emulsifiable concentrate (EC) against different populations of the cattle tick Rhiphicephalus Boophilus microplus (UFRRJ, RGS and Lages). Tests were carried out over engorged females using immersion technique (Drumond 1973). Solutions prepared from dilution of EC were tested at concentrations of 400, 200, 100, 50 e 25 ppm. Results showed that UFRRJ strain presented lower efficacy values as compared to RGS and Lages strains at all concentrations tested, ranging between 56,93% and 76,57%, while RGS strain reported to be effective from 90,76% to 94,95%. Development of EC formulations containing fipronil enables in vitro tests allowing checking the sensitivity of R.B. microplus populations.