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

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 chlorfenvinphos 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

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

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 chlorfenvinphos 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

Displacement of Rhipicephalus decoloratus by Rhipicephalus microplus (Acari: Ixodidae) in the Eastern Cape Province, South Africa

The objective of the study was to establish to what extent the native tick species Rhipicephalus decoloratus had been displaced by the invasive introduced tick, Rhipicephalus microplus at two communally grazed areas in the Eastern Cape Province, South Africa. To this end ticks were collected monthly from 5 cattle over a period of 2 years and from 10 drag-samples of the vegetation over a period of one year at each locality. Whereas 10 years previously only R. decoloratus and no R. microplus had been recorded in the vicinity of the two sites, R. microplus now comprised the bulk of collections at both. Furthermore, significantly greater numbers of R. microplus were collected from cattle at both localities during the 2nd year of the survey than during the 1st (P<0.05 and P<0.01). In addition to 83 instances of intraspecific coupling, there were 17 instances of R. microplus males coupled with R. decoloratus females. Collections made from cattle and goats on 2 farms close to the study sites revealed that R. microplus was present on both host species and that it significantly outnumbered R. decoloratus on one of the farms (P<0.001). R. decoloratus and R. microplus larvae as well as larvae exhibiting characteristics of both species were collected from the vegetation.National Research Foundation of South Africa.http://www.springerlink.com/content/100158/hb2013ab201