Acaricidal Activity o f Ethanolic a nd Volatile Extracts of The Leaves of Selected Plants Used in Veterinary Pharmacopeia on The Larvae of Rhipicephalus Microplus in Benin

Abstract

A study was conducted on the effectiveness of ethanolic and volatile e xt racts of the leaves of four plants acclimat ized in Benin on Rh ipicephalus microplustick, aiming to contribute to the research of acaricides, which are effective on these ticks and harmless to the environment. To this effect, the mod ified larvae immersion test was performed to determine the effectiveness of the e xtracts on the larvae of Rhipicephalus mic roplus aged 7 to 14 days. 5% concentration of the two types of extracts of Lantana camara L., Hyptis suaveolens (L.)Poit., Tephrosia vogelii Hook. f., and Ocimum gratissimum L. induced the Rhipicephalus microplus larval mortalities,extending from 32.5 to 88% with the ethanolic extracts on first time . Then again, essential oils extracted from these four plants led to 100% mortality from 1.25% of concentration. All the lethal doses at 50 and 90% of mo rtality of volatile extracts were statistically lower than those of the ethanolic e xtracts at 5% level of significance (P < 0.05). The extracts of Ocimum gratissimum L. and Tephrosia vogelii Hook.f were the most active in vitro against Rhipicephalus microplus larvae. The results of the present study propose that, plant extracts constitute a promising option for the natural control against the safe strains of Rhipicephalus microplus in Benin and the world.