Efficacy evaluation of methanolic extracts of Calpurnia aurea and Schinus molle plants against the cattle lice Linognathus vitulli

Abstract Background Ectoparasites of livestock in general and lice in particular pose serious economic losses to the farmer, the tanning industry, and the country as a whole. Although the treatment of ectoparasites have been attempted by various chemical agents, the efficacy of the agents hampered by the development of drug resistance. Thus, Ethnoveterinary botanicals are an alternative control strategy for being sustainable and ecologically sound. Thus, this study aims to evaluate the louscidal activity of crude methanolic extracts of Calpurnea aurea and Schinus molle plants against the cattle lice, Linognathus vituli using the in vitro Adult Immersion Test (AIT). Six graded concentrations of the crude extracts, 6.25, 12.5, 25, 50, 100 and 200 mg/ml, were tested at different time intervals, and temporal changes in tick viability were recorded for 24 hours. Results After 24hrs post-exposure, two higher concentrations (200 and 100 mg/ml) of C. aurea extract caused 100±0.0% and 96.6±3.3% lice mortality, whereas S. molle extract caused 90±5.7% and 83.3±3.3% mortality, respectively. Louscidal activity varies with the type of plant extract, concentration and exposure time. After 24 hours of exposure to the extracts, the highest mortality was recorded for extracts from C. aurea with LC50 values of 8.83 mg/ml compared to S.molle with LC50 values of 16.68 mg/ml. Conclusions The louscidal activity of the plant extracts increases with increasing exposure time and concentration as well. Thus, the plant extracts could be used against Linognatus vituli as a potential alternative for the control of lice. Keywords: Calpurnea aurea, Ethnoveterinary, lice, Adult Immersion Test, Schinus molle