doi:10.1038/nindia.2013.147 Published online 11 November 2013
Researchers have synthesized copper nanoparticles capable of killing fungi that infect important agricultural crops . These nanoparticles could be used as a next-generation agricultural pesticide.
Copper compounds have long been used in agricultural fungicides. However, fungi have grown resistant to existing pesticides. Furthermore, existing synthetic pesticides are harmful to humans. There is thus a need to develop new pesticides that can be used to realize sustainable agriculture without having harmful effects on humans.
To produce a new ecofriendly pesticide, the researchers synthesized copper nanoparticles by reacting copper nitrate and isopropyl alcohol in the presence of a surfactant, cetyl trimethylammonium bromide. They then tested the antifungal efficacy of the nanoparticles against four pathogenic fungi: Phoma destructiva, Curvularia lunata, Alternaria alternata and Fusarium oxysporum. They also compared the antifungal efficacy of the nanoparticles with that of a commercial antifungal agent, bavistin.
The nanoparticles showed remarkable antifungal activity against the four pathogenic fungi. Two of the pathogenic fungi (C. lunata and A. alternate) exhibited resistance to bavistin, but were sensitive to the nanoparticles. The nanoparticles showed maximum antifungal activity against C. lunata followed by A. alternate and minimum activity against P. destructiva.
As copper is a micronutrient of crops, plants will take up any excess nanoparticles. In addition, excess nanoparticles can be detoxified naturally by the benign fungi that are present in the roots of plants. "The nanoparticles can be used as a novel antifungal agent in agriculture to control plant pathogenic fungi as well as a potent disinfectant in poultry and animal husbandry," says Mahendra Rai, a co-author of the study.