Study of chemical composition and larvicidal efficacy of secondary metabolites from aromatic phytoextracts against dengue vector: Aedes aegypti (Linn) (Diptera: Culicidae)

摘要

Mosquitoes have not only threatened human health but also adversely affect human and wild life as theyact as vector for many deadly diseases. Among vector mosquito Aedes aegypti plays a key vector role totransmit viral diseases viz. Dengue, Zika, Yellow Fever and Chikunguniya. The present scenario forvector control strategies exposes the fact of rise in resistance index of mosquitoes against variousavailable synthetic insecticides and also nonresponsive to bacterial larvicides. To overcome thesecircumstances, more emphasis should be given to bio-control strategies using secondary metabolites fromplant extracts; since, they are enriched in bioactive components with larvicidal activity. Present studyanalyzed chemical composition and larvicidal efficacy of flowers of Gliricidia sepium and seeds ofAnnona squamosa in methanolic and hexane extracts. The bioassay for larvicidal activity was carried outusing II, III, IV instar larvae of Aedes aegypti. It was observed that early instar stages showed moresensitivity to EOs as compared to later immature developing stages. The lowest LC50 values shown bysecond, third, fourth instar larvae in methanol extract of Gliricidia sepium as 38.01ppm, 45.65 ppm,60.25 ppm respectively whereas highest LC50 values against II, III, IV instar larvae of Aedes aegypti were77.62 ppm, 95.40 ppm, 128.82 ppm respectively in hexane extract of Annona squamosa. EOs ofGliricidia sepium can be used as an effective biolarvicide to control mosquitoes as environment friendlysolution.