Phytofabricated zinc oxide nanoparticles as a nanofungicide for management of Alternaria blight of Brassica

Plant pathogens resistant to the commercially available fungicides and bactericides even at higher concentrations are the biggest challenge for the farmers to control the losses due to plant diseases. The antibacterial and antifungal potential of nanomaterials makes them a suitable candidate for the control of plant diseases. Thus, the present study reports the phytofabricated zinc oxide nanoparticles (ZnO Np’s) using aqueous plant leaf extract of Terminalia bellerica (Baheda). Characterization of ZnO nanoparticles was done by ultraviolet–visible (UV–Vis) studies, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infra-red (FT–IR) analysis, and transmission electron microscopy (TEM). The presence of pure hexagonal wurtzite crystalline structure of ZnO nanoparticles was confirmed by XRD analysis. The TEM images revealed the spherical to hexagonal shaped ZnO nanoparticles with sizes ranging from 20 to 30 nm. The stabilization of synthesized ZnO nanoparticles through the interactions of terpenoids, steroids, phenylpropanoids, flavonoids, phenolic acids, and enzymes present in the leaf extract was suggested by FTIR analysis. The mechanism of the formation of ZnO nanoparticles using Terminalia bellerica (Baheda) (Tb-ZnO Np’s) as a bioactive compound is proposed. These phytofabricated ZnO nanoparticles (Tb-ZnO Np’s) have shown significant antifungal potential against Alternaria brassicae the causal agent of Alternaria blight disease/leaf spot disease in Brassica species. The microscopic results confirm the changes in mycelium morphology and reduction in the number of spore germination at 0.2 mg/mL concentration Tb-ZnO Np’s.