[Optimization of synthesizing silver nanoparticles from Trichoderma strains for inhibition of Fusarium oxysporum]

With the popularity of green concepts, the use of biological method to synthesize metal nanoparticles is a favored method. Silver nanoparticles (AgNPs) have attracted more and more attention in the control of agricultural diseases, because of their strong antifungal activity and not easy inducing resistance for pathogens. In this study, Trichoderma citrinoviride and Trichoderma velutinous were used to study the most suitable synthesis conditions for AgNPs, and their antifungal activity against Fusarium oxysporum. The silver nanoparticles had an absorbance peak at 400-500 nm, the most suitable synthesis conditions were at standing and light with CL method (mycelium filtrate), AgNO₃ concentration of 2.0 mmol/L, pH of 7, and reaction temperature of 45 °C. AgNPs synthesized by T. citrinoviride and T. velutinous inhibited F. oxysporum, the inhibition effect was better with the increase of silver nanoparticle concentration. When the concentration of AgNPs was 200 mg/L, the antifungal rate from T. citrinoviride and T. velutinous was 33.75% and 36.08%, respectively.