This study successfully synthesized Ag-doped CuO nanoparticles using a
green method with papaya leaf extract. The antibacterial and antifungal
activities of the Ag-doped CuO nanoparticles, together with CuO and Ag
control samples, were evaluated against two representative strains, the
bacterium Pseudomonas syringae and the fungus Pestalotiopsis
mucronatum. The Ag-doped CuO nanoformulation was sprayed onto
golden camellia (Camellia chrysantha) plants infected with rust and leaf
spot diseases in Ba Che commune, Quang Ninh province. The results
indicated that the suspension containing Ag-doped CuO nanoparticles
exhibited strong antibacterial and antifungal activities, in which the
inhibitory effect against P. syringae was superior to that of the individual
Ag and CuO nanoparticles; similar results were observed for P.
mucronatum. After seven days of treatment, rust and leaf spot symptoms
on golden camellia plants were markedly reduced. All plants in the
experimental area showed healthy growth and development.