Vol. 4, Issue 4, Part A (2017)

Author(s): Rajasingh Raveen, Fauzia Ahmed, Muniyasamy Pandeeswari, Daniel Reegan, Samuel Tennyson, Subramanian Arivoli and Manickkam Jayakumar

Abstract: Vector control is by far the most successful method for reducing incidences of mosquito-borne diseases. Plant products have been tested as insecticides against mosquitoes as they are nontoxic to mammals and are promising candidates to replace conventional insecticides. In the present study, the bioefficacy of crude solvent leaf extracts of Alternanthera sessilis (Amaranthaceae), Amaranthus dubius (Amaranthaceae), Sesbania grandiflora (Fabaceae) and Solanum nigrum (Solanaceae) were tested on the immature stages of the dengue, chikungunya, yellow fever and Zika virus vector, Aedes aegypti. The eggs, larvae and pupae of Aedes aegypti were exposed to different concentrations viz., 62.5, 125, 250 and 500mg/L. After 24 hours of exposure, the larval and pupal per cent mortality was assessed and their LCâ‚…â‚€ and LC90 values calculated. However, per cent egg mortality was calculated after 72 hours of exposure. Among the different crude solvent extracts of the plants tested, the butanol extract of Alternanthera sessilis caused highest egg mortality rate of 86% and the ethanol extract of Solanum nigrum exhibited highest larvicidal and pupicidal activity and LC50 and LC90 values were 34.12, 88.11 and 44.15, 111.70mg/L respectively. The successful results of preliminary studies on mosquitocidal potential of plant extracts encourage further effort to investigate the bioactive compounds in those extracts that might possess good immature mosquitocidal properties when isolated in pure form.

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