An aqueous extract of Maerua edulis (Gilg & Ben) DeWolf tuber is as effective as a commercial synthetic acaricide in controlling ticks on cattle in vivo

Farmers in Zimbabwe claim that plant extracts of Cissus quadrangularis, Aloe vera and Maerua edulis are effective in controlling cattle ticks. On-station experiments were conducted at Henderson Research Station to determine the in-vivo efficacy of crude aqueous extracts of Cissus quadrangularis (succulent stems), Aloe vera (succulent leaves) and Maerua edulis (leaves and tuber) at concentrations of 15%, 15% and 10% w/v respectively, against cattle ticks. An amitraz-based acaricide and water were used as positive and negative controls, respectively. Thirty Mashona steers were allocated to the six treatments in a completely randomised design experiment where each animal was an experimental unit replicated five times. The animals were each sprayed weekly with 5 L of the test or control solutions using a knapsack sprayer after which full body tick counts were recorded every other day for seven weeks. The experiments were conducted between January and February when conditions are optimal for tick development. The M. edulis tuber extract was as effective as the amitraz-based commercial acaricide. The other three plants extracts were, however, as ineffective as the negative control (water). Maerua edulis tuber plus soapy water-oil extract is effective against cattle ticks and have potential to be developed into an acaricidal product and thus benefit mostly resource-challenged smallholder farmers who cannot afford commercial synthetic acaricides. In vivo studies using acaricidal plants are rare.