Evaluation of larvicidal potential of flavonoid extracted from Sphaeranthus indicus Linn (Asteraceae) for controlling mosquito Culex quinquefaciatus (Culicidae) Diptera

Abstract

The entire world is facing the problem of vector borne diseases, which are one of the leading causes of deaths in developing countries. This is not because of any lapse or failure of disease control operations but due to enormous population growth of various types of vectors, among which mosquitoes are playing a major role. Their control is a difficult task due to a variety of factors including the development of insecticide resistance in the insects and environmental pollution. No doubt, the chemical insecticides will be continuously used for mosquito control but a cheap, less harmful and eco-friendly alternative is badly needed. The chemicals derived from plants, have been projected as weapons in future mosquito control programs. They act as general toxicants, growth inhibitors, reproduction inhibitors, repellents and oviposition deterrents. So far, more than thousand plants have been searched for biopesticides, not only to control the vectors, but also other pests of agricultural importance. Plants have evolved a variety of secondary metabolic compounds, some of them for providing protection from phytophagous insects. Flavonoids are phenolic secondary metabolites found in a wide range of plant tissues, possessing a common aromatic ring, bearing one or more hydroxyl substituents. Flavonoids are most commonly known for their antioxidant activity. In the present piece of research work it was observed that the flavonoid extract of Sphaeranthus indicus proved to be a very effective mosquito larvicide and can provide eco-friendly alternative to synthetic insecticides. The findings suggest that plant extracted bio-pesticides may play a major role in designing an integrated vector control program in near future.