Antifungal activity of biosynthesized silver nanoparticles against three maize leaf phytopathogens

Bamboo leaf extract was applied to biosynthesize silver nanoparticles in condition of silver nitrate (AgNO/sub 3/). Several parameters like extract volume, concentration of AgNO/sub 3/, and potential of hydrogen (pH) were carried out to confirm the optimized synthesis system. Synthesized silver nanoparticles were characterized through UV-Vis spectrophotometer, transmission electron microscope (TEM), scanning electron microscope (SEM), and energy dispersive X-ray detector (EDX). In addition, inhibition effect of silver nanoparticles towards three maize leaf phytopathogens of Bipolaris maydis, Exserohilum turcicum, and Curvularia lunata was determined. The optimized biosynthesis condition included 15 mL extract, 8 mM AgNO3 at pH 7. The obtained nanoparticles with an average size of 13 nm demonstrated prominent antifungal activity against the three phytopathogens, and the highest inhibition rate reached 93.6% at 200 μg/mL of silver nanoparticles. In addition, when the concentration reached 100 μg/mL the conidia germination of these three pathogens was completely inhibited. The results obtained here provide a neotype pathway for comprehensive control phytopathogens, and it is possible to screen one kind of novel bacteriostatic agents. (author)