Agave angustifolia1 Extracts as Natural Larvicides and Growth Inhibitors against Aedes aegypti and Culex quinquefasciatus2 Mosquitoes

Larvicidal and growth inhibitory (RGI) effects of crude extracts (ethanol, methanol, hexane) were studied using World Health Organization guidelines. Chemical analysis confirmed alkaloids, anthraquinones, coumarins, flavonoids, tannins, and terpenoids in the extracts. Ethanolic extract killed 100% of Aedes aegypti (L.) within 72 hours, with LC50 and LC90 values of 259.18 and 272.25 ppm. Hexane extract at 48 and 72 hours had 803.19 pp LC50 and 1133.55 ppm LC90 , while methanolic extract had 348.78 and 251-95 ppm for LC50 and LC90 . Against Culex quinquefasciatus (Say), ethanolic extract was most effective (LC50 : 89.56 ppm, LC90 : 1,035.33 ppm). Hexane extract had limited efficacy (LC50 : 2667.84 ppm), and methanolic extract had LC50 of 59.8 ppm. Methanolic extract prolonged pupal stages, with delays of 2.27 and 2.36 days at concentrations of 125 and 62.5 ppm, resulting in RGI of 1.67 and 1.74 for Ae. aegypti . Hexane extract extended insect development by 9.64 and 9.34 days at concentrations of 1,000 and 500 ppm, yielding RGI of 0.22 and 0.77. For Cx. quinquefasciatus , ethanolic extract at 62.5 ppm had RGI of 0.22, while methanolic extract at least concentration had RGI of 0.25, with extended larval and pupal periods of 16.25 and 2.87 days. Hexane extract at 125 and 62.5 ppm prolonged the larval period to 27.25 and 29.87 days. In summary, ethanol and methanol extracts are promising secondary metabolites for alternative mosquito control, showing potential for research and development in insecticide strategies.