Chromolaena odorata (L.) R.M. King & H. Rob. Leaf Extract as Potential Control Agent for Rhipicephalus microplus Canestrini, 1888
The huge economic losses due to tick infestation in livestock and the problems associated with the use of synthetic acaricides require cheaper and safer interventions for tick control. This study investigated the potential use of dichloromethane crude extract of Chromolaena odorata leaves in the control of Rhipicephalus microplus using glass plate repellency bioassay and topical application procedures. The percentage tick repellency at 3.125 mg/ml and higher concentrations of the extract ranged from 33 to 80. The extract exhibited lethal effects on R. microplus with LC50 of 22.60 mg/ml. The mean percentage tick mortality was significantly higher compared with that of the control at 6.25 mg/ml (p = 0.044), 12.5 mg/ml (p = 0.017), 25 mg/ml (p = 0.006) and 50 mg/ml (p < 0.0001) of the extract. Tick mortalities for all concentrations of the extract were significantly higher compared with that of Amiraz 20, a synthetic acaricide commonly used in livestock production. The extract demonstrates potent acaricidal properties and may serve as potential source for developing acaricidal compounds.