ABSTRACT
Pyrus communis is a common fruit of temperate region, its domestication and origin is at two different points, Asia and China. Pear fruits bearing brown spot symptoms were picked, and pathogen was isolated and poured on Potato Dextrose Agar (PDA) media. On basis of molecular and molecular analyses, this isolated pathogen was identified as Alternaria alternata. Zinc oxide nanoparticles (ZnO NPs) were prepared from Theveti peruviana leaf extract and were characterized through various techniques Fourier Transform Infrared Spectroscopy (FTIR) analysis of prepared ZnO NPs depicted the presence of agents responsible for stabilization and reduction such as alkenes, alkynes, nitro compounds, alkyl halides, aromatic compounds and aliphatic amines. X-ray diffraction (XRD) analysis confirmed the size (27 nm) and crystalline nature of ZnO NPs. Scanning electron microscopy (SEM) depicted the irregular shape of the prepared ZnO NPs. Mass percentage of zinc (79.84%) and oxygen (20.16%) was depicted using Energy Dispersive X-Ray (EDX) analysis. The in vitro and in vivo antifungal activity (A.F) of prepared NPs against A. alternata was confirmed by poisoned food technique and wound inoculation method. On the basis of which it was concluded that 1.0 mg/mL concentration of ZnO NPs could effectively inhibit A. alteranata growth and minimize the risk of brown spot of pear. SEM images of A. alternata under 1 mg/mL NPs showed the deformation in morphology of A. alternata. ZnO NPs also aided in the preservation of its various organoleptic and biochemical properties. The high percentage of soluble solids, firmness, ascorbic acid and sugars demonstrated its high quality. It has been concluded that 1 mg/mL ZnO NPs can effectively control brown spot of pear while maintaining its quality. In addition, the method might be applied to control emerging diseases in an ecofriendly way to meet the global food demand. RESEARCH HIGHLIGHTS: Isolation and characterization of pathogen causing brown spot in pear. Pathogenicity of A. alternata was checked on healthy fruits. Thevetia peruviana leaf extract was used for the synthesis, characterization and antifungal assay of ZnO Nanoparticles. Green synthesized nanoparticles can be economically effective alternative fungicide for the large scale in agriculture fields.