Mosquito borne diseases are one of the most public health problems in the developing countries. Larviciding is a successful way of reducing mosquito densities in their breeding places before they emerge into adults. The present study aims at exploring the Costus speciosus Koen aqueous extracts for larvicidal property. Larvicidal potential of stem, leaf and rhizomes of Costus speciosus aqueous extracts were evaluated against third and fourth instar larvae (Aedes aegypti). Aqueous extracts was prepared by maceration technique, and the larvicidal assay was carried out at 5 test concentrations of 100, 250, 500, 1000, 2000 μg/ml. Larvicidal potential was determined at 0, 1, 2, 3, 4, 5, 6, 12 and 24 hours and the percentage mortality was calculated. All the extracts had shown dose dependent activity with the maximum larvicidal potential was seen at 2000mcg/ml for leaf, stem and rhizome. It can be concluded that, larvicidal potential of the leaves are better than that of the other parts such as rhizomes and stem.
