NEW APPROACHES TO CONTROL FILARIAL PARASITE AND ITS VECTORS USING SELECTED NATURAL EXTRACTS AS SAFE CONTROL AGENTS

Abstract

The present study was conducted to evaluate the mosquito larvicidal effect of some plant extracts against Culex pipiens , the main vector of lymphatic filariasis in Egypt. From eighteen plant extracts screened for their larvicidal activity against Cx. pipiens larvae, only eleven showed toxicity with different grades. Petroleum ether extracts of both Achillea (Ac.) fragrantissima and Nerium (N.) oleander were the most toxic plant extracts with LC50 values of 45.23 and 95.7 ppm respectively. The present results revealed that larvae were more susceptible to petroleum ether extract as a whole than their fraction. Phytochemical screening of Ac. fragrantissima and N. oleander using gas liquid chromatography was carried out to identify their hydrocarbons, sterols and/or triterpenes as well as fatty acid content. Culex p1pwns larvae were susceptible to insecticide (cyphenothrin) and IGR (chlorfluazuron). •. The addition of small concentration (LC10) of cyphenothrin to different concentrations of Ac. fragrantissima increased its efficacy comparing to • insecticide alone. The third instar larvae were exposed to sublethal concentrations (LC40) of both Ac. fragrantissima, cyphenothrii1 and their mixture and N. oleander. Achillea fragrantissima cyphenothrin and their mixture gave more effect than N. oleande on fecundity, e.gg hatching, pupation and se. x ratio. Treatment 6f Cx. pipiens larvae with sublethal concentration (LC40) of Ac. .fragrantissima, cyphenothrin and their mixture affected vect'of. competance to Wuchereria bancrofti including ingestion of, microfilariae, infection, infective and survival rates, distribution ofL3 larvae in mosquito adults and experimental index.