RESUMEN
Citrus canker is a disease of economic importance and there are limited biocontrol agents available to mitigate it in an integrated manner. This study was conducted to combat citrus canker disease using biologically active nanoparticles (Ag, Cu and ZnO and 300, 900, 1200, and 1500 ppm) synthesized from macromolecules extracted from alga, Oedogonium sp. The synthesis of the nanoparticles was confirmed by UV-Vis Spectroscopy, FTIR, SEM, XRD, and DLS Zeta sizer while their efficacy was tested against Xanthomonas citri by measuring zone of inhibition. Results indicated that Ag and Cu nanoparticles at 1200 ppm exhibit the highest activity against Xanthomonas citri, followed by ZnO at 1500 ppm. The minimum inhibitory concentrations (MIC) of Ag, Cu and ZnO NPs were 1, 2 and 10 mg mL-1, respectively while minimum bactericidal concentrations (MBC) were for Ag and Cu 2, 4 mg mL-1 and for ZnO NPs more then 10 mg mL-1, were required to kill the X. citri. Bacterial growth respectively. Macromolecules extracted from algal sources can produce nanoparticles with bactericidal potential, in the order of Ag > Cu > ZnO to mitigate citrus canker disease and ensuring sustainable food production amid the growing human population.