Resumen

NTONDINI, Z; VAN DALEN, E M S P  y  HORAK, I G. The extent of acaricide resistance in 1-, 2- and 3-host ticks on communally grazed cattle in the eastern region of the Eastern Cape Province, South Africa. J. S. Afr. Vet. Assoc. [online]. 2008, vol.79, n.3, pp.130-135. ISSN 2224-9435.

In order to determine the extent of acaricide resistance in the eastern region of the Eastern Cape Province 1-, 2- and 3-host ticks were collected from cattle at 59 dip-tanks over a period of 2 years. These ticks were tested for resistance against 3 compounds, namely amitraz, cypermethrin and chlorfenvinphos. The Shaw Larval Immersion Test detected emerging resistance to amitraz in Rhipicephalus (Boophilus) microplus at 2 dip-tanks and resistance at a 3rd. It also revealed resistance in this tick to cypermethrin at 1 dip-tank and emerging resistance to chlorfen vinphos at 8 dip-tanks and resistance at 2. Rhipicephalus evertsi evertsi was susceptible to amitraz and cypermethrin at all dip-tanks, but showed emerging resistance to chlorfenvinphos at 7 dip-tanks and resistance at 4. Rhipicephalus appendiculatus was susceptible to amitraz and chlorfenvinphos at all dip-tanks and demonstrated emerging resistance to cypermethrin at 1. With the exception of R. (B.) microplus, in which emerging resistance to amitraz was detected at 1 dip-tank by the Reproductive Estimate Test, all 3 tick species at all dip-tanks at which sufficient numbers of ticks had been collected were susceptible to the 3 acaracides in both the Egg Laying Test and the Reproductive Estimate Test. The localities at which acaricide resistance was recorded were mapped.

Palabras clave : acaricide resistance; amitraz; chlorfenvinphos; cypermethrin; Eastern Cape Province; ixodid ticks; Rhipicephalus appendiculatus; Rhipicephalus (Boophilus) microplus; Rhipicephalus evertsi evertsi.

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