In Vitro Evaluation of Ethanolic Extracts ofAgeratum conyzoidesandArtemisia absinthiumagainst Cattle Tick,Rhipicephalus microplus
In vitro efficacy of ethanolic extracts obtained from the aerial parts ofAgeratum conyzoidesandArtemisia absinthiumwas assessed onRhipicephalus microplususing adult immersion test (AIT). Five concentrations of the extract (1.25%, 2.5%, 5%, 10%, and 20%) with three replications for each concentration were used in the bioassay. In AIT, the maximum mortality was recorded as 40% and 66.7% at 20% concentration forA. conyzoidesandA. absinthium, respectively. Acaricidal activity was found to be higher in the extract ofA. absinthiumwith LC50and LC95values of 11.2% and 61.7%, respectively. Egg mass weight of the live ticks treated with different concentrations of the extracts was significantly(P<0.05)lower than that of control ticks; consequently, the reproductive index and oviposition values of the treated ticks were reduced significantly(P<0.05). TheA. conyzoidesinhibited 90% hatching of eggs at the 20% concentration, whereasA. absinthiumshowed 100% inhibition at 5%, 10%, and 20% concentrations. The results show thatA. absinthiumhas better acaricidal properties thanA. conyzoidesand could be useful in controllingR. microplus.