Ticks and tick-borne diseases continues to be a global problem with direct and indirect impact on both humans and animals. The use of acaricides has been a common tick control method because of their ease of use and commercial availability; however, there are rising cases of resistance to synthetic acaricides, resulting in serious economic losses. This study aimed to evaluate the acaricidal activity of crude extracts and fractions from the leaves of Croton hirtus against the cattle tick Rhipicephalus annulatus. An adult immersion test method was adopted to assess the acaricidal potential of the C. hirtus extract and fractions at varied concentrations (1–20%), with 2% Tween-80 and 2% cypermethrin serving as negative and positive controls, respectively. Field ticks from cattle were collected, grouped (n = 10), and exposed to various test preparations. Tarsal reflexes, photosensitivity, reproductive indices, and oviposition inhibition were measured at 6 h post-immersion and daily for 14 days. Microsoft Excel® 2017 spreadsheet was used for data collation, and results were analysed with one-way ANOVA and Tukey HSD test on GraphPad (Prism 7), with p ≤ 0.05 considered statistically significant. Findings showed 100% tick mortality and a 95% inhibition of oviposition with the chloroform fraction (1%). The egg mass varied across the treatment groups, with the chloroform fraction being the least (< 10 mg), while the aqueous extract and other fractions were like the negative control. The mean adult mortality rate was not statistically different across the treatments. The chloroform fraction (1%) of C. hirtus leaves exhibited superior acaricidal activity against R. annulatus ticks compared with other fractions. Future research should explore and document the mechanisms of action of this essential oil as a natural tick control remedy.
Adekoya et al. (Mon,) studied this question.