Acaricidal potential and phytochemical evaluation of ethanolic extract of Argemone mexicana against Rhipicephalus microplus

Argemone mexicana belonging to family Papaveraceae, traditionally used as medicine for jaundice, dropsy, scabies and cutaneous affections. The aim of this study was to determine the acaricidal effect of ethanolic extract of the whole plant of A. mexicana against Rhipicephalus microplus (Canestrini) by in vitro tests and deduce different phytochemical of the extract with help of Fourier-transform infrared (FTIR) spectroscopy and Gas chromatography mass spectrometry (GC-MS). The effect of plant extract on the adult and larva of R. microplus were observed by reporting its mortality and reproductive efficacy. The extract caused an adult mortality of 73.3% and larval mortality of 70.7% while the inhibition of oviposition was 77.1%. The reproductive indices ranged from 0.116 to 0.177 and LC 50 was 46.8 mg/ml. The FTIR spectroscopy analysis revealed the presence of functional groups like carboxylic acids, alkynes, alcohols, aromatic esters and alkyl hallides and GC-MS analysis depicted phytoconstituents like tetradecanoic acid, n-hexadecanoic acid and hexadecanoic acid methyl ester that may be attributed to the tick-repellant acaricidal activities of the of stem and leaves of A.mexicana. The in vitro studies on A. mexicana depicted encouraging results for use as a biopesticide against bovine tick, but further in vivo and toxicity studies are warranted in order to obtain a viable green solution against R. microplus.