Resistance to acaricides in ticks in the Eastern Cape Province
Whitehead, G.B.
South African Medical Journal 47(8): 342-344
1973
ISSN/ISBN: 0256-9574 PMID: 4120787 Document Number: 69360
The history of the development of acaricide resistance in Boophilus decoloratus (Koch) in the eastern Cape Province of South Africa is briefly reviewed. Arsenic, to which resistance appeared in 1938, was replaced first by BHC, to which resistance appeared after 18 months of general use, and then by DDT, to which resistance appeared after about 5 years. Various organophosphates and carbamates that replaced DDT for tick control have been used effectively for nearly 15 years, but organophosphate-resistant ticks have been recorded from isolated areas. Resistance to chlorinated hydrocarbons has also been recorded in Rhipicephalus evertsi Neum. and R. appendiculatus Neum. The biochemical mechanisms of resistance in ticks are described, and attention is drawn to the problem posed by the fact that routine dipping of cattle in different acaricides results in the selection of strains of ticks with a progressively wider spectrum of resistance.