Oviposition altering and Ovicidal Efficacy of Root extracts of Argemone mexicana against Dengue Vector, Aedes aegypti (Diptera: Culicidae)

Abstract

Laboratory evaluations were carried out to evaluate the oviposition altering and ovicidal efficacy of root extracts of Argemone mexicana against the dengue vector Aedes aegypti. The extracts were prepared in five different solvents; petroleum ether, hexane, benzene, acetone and ethanol. Our studies established the efficacy of the non-polar extracts over the polar extracts. The oviposition deterrence studies established the petroleum ether root extract as the most efficient extract, with percent effective deterrence of 21% at 40 ppm reaching to 100% at 1000 ppm. The petroleum ether root extract also showed a high effectual deterrence at 100 ppm (ED% - 73%) at which other extracts were rendered comparatively ineffective. Most of the other extracts were not found to be significantly effective at lower concentration but showed gradual increase in the deterrent potential with increasing concentrations. On 24 h exposure of freshly laid eggs of Ae. aegypti with different root extracts, the non-polar extracts showed appreciable ovicidal potential at higher concentrations. The petroleum ether and hexane root extracts proved to be the most effective ovicides against Ae. aegypti eggs causing only 4.9 and 8.9% hatch respectively at the highest concentration. The benzene root extracts showed an appreciable decrease in the egg hatchability at higher concentrations but could not sustain their ovicidal effect at lower concentrations. The polar extracts, however, were the least effective ovicidal agents.