Abstract

A study was conducted on the effectiveness of ethanolic and volatile extracts of the leaves of four plants acclimatized in Benin on Rhipicephalus microplus tick, aiming to contribute to the research of acaricides, which are effective on these ticks and harmless to the environment. To this effect, the modified larvae immersion test was performed to determine the effectiveness of the extracts on the larvae of Rhipicephalus microplus aged 7 to 14 days.
5% concentration of the two types of extracts of Lantana camara L., Hyptis suaveolens (L.)Poit., Tephrosia vogeliiHook. 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 mortality of volatile extracts were statistically lower than those of the ethanolic extracts at 5% level of significance (P < 0.05). The extracts of Ocimum gratissimum L. and Tephrosia vogeliiHook.f were the most activein vitroagainst 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.

Key words: larvae, Rhipicephalus microplus, Lantana camara, Hyptis suaveolens, Tephrosia vogelii, Ocimum gratissimum, Benin