Residual Effectiveness of Crude Ethanol Extracts of Mature Green Fruits of Endod Phytolacca dodecandra (L' Herit) against An. gambiae (Diptera: Culicidae) Larvae

Abstract

Mosquitoes are vectors of aborvirals and malaria and are a threat to public health. We evaluated residual effectiveness of crude ethanol extracts of Endod Phytolacca dodecandra (L’ Herit) leaves and mature green fruits in water against Anopheles gambiae (Diptera: Culicidae) larvae to determine duration of protection of the extract against An. gambiae mosquitoes. Stock’s solution of 80 mg/100 mls of crude ethanol extract of mature green fruits and leaves of Endod were prepared using rain harvested water and left to stand. Six such stocks’ solutions were prepared on six separate days. Each of the stock’s solutions was serially diluted to 40, 20, 10, 5 and 2.5 mg/100 ml and poured in five sets of separate plastic containers. Each container measuring 6 cm top × 5.7 cm bottom × 3.5 cm height contained a solution of a particular concentration. Twenty L3s were exposed per container. Extracts of Neem leaves and deltamethrin were used as positive and rain water alone as negative control. WHO threshold of>80% mortality was used to assess residual effectiveness. Mortality was determined after 24 hours. Resudual effectiveness was dose dependent. As low as 10 mg/100 mls solutions of freshly to two day old preparations of crude ethanol extract of mature green fruits and leaves of Endod killed more than 80% larvae. The solutions remained effective for three day only. Effectiveness reduced rapidly after day four. Crude ethanol extracts of Endod mature green fruits and leaves have a residual period of three days in water against An. gambiae larvae.