Larvicidal activity of pristine Alpha-MnO sub(2) nanostructures: An environmentally benign approach for combating mosquito (Diptera: Culicidae) menace

Abstract

Diseases transmitted by mosquitoes claim more than 700,000 lives annually. Mosquitoes are the vectors for the transmission of parasites, bacteria and viruses. The present work highlights the mosquito larvicidal activity of manganese oxide (MnO sub(2)) nanoparticles. MnO sub(2) nanoparticles synthesized by the wet chemical redox method were characterized using Powder X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron microscope (TEM). XRD and TEM studies reveal that the synthesized MnO sub(2) nanocrystals have a hollandite (Alpha-MnO sub(2)) structure with a sea-urchin like morphology having a high surface area. Larvicidal activity of MnO sub(2) nanoparticles was assessed against the larvae of Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti), and Anopheles stephensi (An. stephensi), and reveals the toxic nature of the nanoparticles against larvae of all the three mosquito species tested. Maximum efficacy has been observed against Cx. quinquefasciatus larvae, with LC sub(50) value of 5.39 ppm, followed by Ae. aegypti at 8.283 ppm and 168.324 ppm against An. stephensi. This study demonstrates toxic effects exerted by the chemically synthesized MnO sub(2) nanoparticles in a species-specific manner. Overall, this study highlights the potential of MnO sub(2) nanoparticles as an effective mosquito control agent.