Larvicidal Efficacies of Certain Plant Extracts against Fourth Instar Larvae of Aedes albopictus Skuse
International Journal of Scientific Research in Biological Sciences
Asian tiger mosquito, Aedes albopictus (Diptera: Culicidae) is becoming a competent vector for dengue, chikungunya and other viruses. Most common insecticides and repellents may exert toxic effect on non-target organisms including man. Hence alternative vector management strategies need to be explored. Biopesticides including plant products may be employed as mosquito control agents. In this study, an attempt has been made to evaluate the insecticidal potential of aqueous leaf extracts of
... endrum infortunatum, Ailanthus excelsa, Aloe vera and Sesbania grandiflora on mortality of fourth instar larvae of Aedes albopictus. Larvicidal effect was studied at doses ranging from 100 to 600 ppm. The results indicate that aqueous leaf extracts of C. infortunatum (LC 50 -614.6ppm) showed a higher mortality rate than A. excelsa, A. vera and S. grandiflora. Biochemical analyses revealed an increase in protein, glycogen and lipid concentration in plant extract treated larvae, when compared to control ones, whereas amount of amino acid decreased in treated larvae. This clearly indicates a physiological as well as biochemical imbalance in larvae, induced by plant extracts. Presence of secondary metabolites such as alkaloids, flavonoids, tannins, glycosides, phenols was detected by qualitative analyses of plant extract which may contribute for its insecticidal effect. For Aloe vera, the mortality was shown at 600 ppm only (5.5%) and for Sesbania grandiflora, the mortality was shown Int.