Abstract:
The African blue tick, Rhipicephalus (Boophilus) decoloratus, is a common tick species found in
South Africa and affects cattle production as well as vectoring pathogens in regions of Africa
and Asia. In an attempt to develop a non-toxic, lower cost and environmentally friendly tick
control method, twenty-six plant extracts were prepared from thirteen plant species using 99.5%
acetone and 99% ethanol. The adapted Shaw Larval Immersion Test (SLIT) was used to test the
efficacy of the extracts. A 1% solution of each of the plant extracts was prepared for efficacy
testing and the ethanol extracts were found to have better acaricidal activity than the acetone
extracts. The ethanol extract from the leaves and flowers of Calpurnia aurea had the best activity [Corrected Mortality (CM) = 82.9%] which was followed by the stem extract of Cissus
quadrangularis (CM = 80.4%). The plant species were screened against Vero cells and were
found to have low toxicity. From this study it is apparent that there is potential for the
development of botanicals as natural acaricides against R. (B.) decoloratus.
