Control of Fusarium wilt disease of tomato and improvement of some growth factors through green synthesized zinc oxide nanoparticles

Fusarium wilt of tomato is a destructive disease worldwide, causing economic losses every year. In this research, a biological method was used to control the disease. Metabolite solution of Trichoderma harzianum was used for green synthesis of zinc oxide nanoparticles (ZnO-NPs) from zinc nitrate (ZnNO₃), and GC/MS analysis of metabolite was performed. Then, the antifungal activity of the synthesized ZnO-NPs was evaluated in vitro and in vivo conditions. Results were compared to different concentrations of Iprodione+Carbendazim (Rovral-TS®) fungicide. Synthesized ZnO-NPs were characterized using ultraviolet-visible spectrometry (UV-Vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). UV-Vis spectra showed an intense peak at 339 nm. X-ray diffraction pattern showed the crystalline nature of the ZnO-NPs. FTIR revealed various functional groups including phenols, ketones, aldehydes, aliphatic and primary amines, nitriles, alkanes and alkynes in synthesized ZnO-NPs. The size of the ZnO-NPs was determined to be in the range of 25–60 nm. Based on atomic absorption spectroscopy, the foliar application of synthesized ZnO-NPs led to acceptable level of zinc concentration in the leaves and it can be useful to compensate zinc deficiency. Some growth factors showed relative improvement compared to the control and some of them were not significantly different. Complete inhibition of mycelia growth of F. oxysporum was observed in 100 µg/ml concentration of ZnO-NPs in vitro conditions and disease severity was significantly reduced in vivo conditions, indicating that green synthesized ZnO-NPs gave better results in low concentration than the fungicide.