Insecticidal activity of metallic nanopesticides synthesized from natural resources: A review

Abstract

Insects are a major source of human diseases and agricultural loss, but actual insecticides are highly toxic for humans, thus calling for advanced pesticides. For instance, metallic nanoparticles have recetly attracted research attention as pesticides, because metallic nanoparticles can be synthesized from natural resources by green methods. Here we review metal-based nanoparticles as insecticides to fight mosquitos, ticks, blood-feeding parasites, and crop pests. Metal nanoparticles are made of gold, copper, iron, palladium, and nickel, and oxides of zinc, titanium, aluminum, iron, copper, magnesium, and cadmium. Toxicity is induced by intrinsic properties of nanoparticles, release of metal ions, redox disequilibrium, enzyme inactivation, and genetic damage. We also compare metal nanopesticides with traditional pesticides. We found that metallic nanoparticles exhibited larvicidal and pupicidal activities against various mosquito vectors of dengue fever, malaria, and other diseases. The phytochemicals of the raw natural materials for the synthesis of metallic nanoparticles may also creat pesticidal properties. Insecticidal efficacy is controlled by sizes, shapes, and charges of nanoparticles. Issues regarding the realistic usage of metallic nanopesticides, such as the appropriate dosage, insecticidal efficiency in the field, and their potential risks to human health and the eco-environment, require further investigation.