Larvicidal potency of Spatholobus parviflorus (DC.) Kuntze against Aedes albopictus (Diptera: Culicidae).

Abstract

Aedes albopictus (Diptera: Culicidae) is one well-established vector of a series of mosquito-borne diseases. The larval stage of their life cycle is best suited to control a large population of mosquitoes easily. Controlling the larval stage of such vectors can also control the spread of the pandemic disease through the vector. Larvicides, which are synthetic, is a promising solution now. This kind of synthetic larvicides affects humans and animals equally and damages the environment through unscientific and widespread use. Beyond that, their continued use could create selection pressure and, thus, a resistant population. Plant-based larvicide is a way to overcome the shortcomings of synthetic larvicides. This study infers the larvicidal potency of Spatholobus parviflorus (DC.) Kuntze solvent extracts (SPSE) and crude water extracts (SPWE) against Aedes albopictus, using the dose-response larvicidal assay. The assay conducted using different concentrations of extract (0.1, 0.2, 0.3, 0.4, and 0.5%) and standard (bleaching powder), with the concentrations 0.01, 0.02, 0.03, 0.04 and 0.05%. The nourishment of the larvae is maintained by supplementing each of the Petri plates with 10 mg of larval food. The mortality of the nascent is recorded in a successive time interval of 12 h, up to 72 h. A significant (P<0.05) mortality was observed in SPWE of the leaf. The observed data analyses using Log probit analysis, and the highest LC50 (lethal concentration to kill 50% of the population), 0.57 mg/ml, is observed at the 24th h of the larvicidal assay. The lowest LC50, 0.35 mg/ml is observed at the 60th h of the larvicidal assay. In conclusion, the results show that S. parviflorus leaf water extract (SLWE) has significant larvicidal activity against A. albopictus, and this is the first account for the larvicidal potency of S. parviflorus. The study concludes that S. parviflorus is an excellent candidate plant for the development of a plant-based larvicide. This possibly influences a reduction in the use of typical household bleach and conventional chemical larvicides.