Larvicidal activity of crude extract of Morinda morindiodes (Jologbo)leaves on Anopheles mosquitoes larvae

Abstract

Mosquitoes are known vectors for transmitting malarial parasites. To prevent proliferation of mosquito borne diseases and to improve public health, mosquito control has been employed using unfriendly synthetic
insecticides. Alternative to these synthetic agents are natural products. The present study was designed to investigate the larvicidal activity of the Pet-ether crude extract of the leaves of Morinda morindiodes (Jologbo), Rubiaceae family, against the fourth instar larvae of Anopheles mosquitoes. A quantity of the dried and powdered leaves was exhaustively extracted by the Soxhlet extraction method using petroleum ether (60-80%). Samples of larvae were transferred into the extract at the various concentrations (50, 100, 150, 200, and 250 ppm). The mortality was observed and the dead larvae counted after 15 min., 30 min, 40 min, 1 hr, 3 hrs and 5 hrs. There were progressive increases in the lethal effect on the Anopheles larvae with respect to time and concentration. Lethality was observed from 1 hr, at a concentration of 200 ppm and by the 5th hour, all the concentrations were lethal. After probit analysis, the calculated LC₅₀ (larvae) was 55.96 ppm/5 hrs.

Keywords: Morinda morindiodes, Larvicidal, Jologbo, Malaria control, herbal pesticide.