First Report of Fruit Rot of Cherry and Its Control Using Fe 2 O 3 Nanoparticles Synthesized in Calotropis procera .

Cherry is a fleshy drupe, and it is grown in temperate regions of the world. It is perishable, and several biotic and abiotic factors affect its yield. During April-May 2021, a severe fruit rot of cherry was observed in Swat and adjacent areas. Diseased fruit samples were collected, and the disease-causing pathogen was isolated on PDA. Subsequent morphological, microscopic, and molecular analyses identified the isolated pathogen as Aspergillus flavus . For the control of the fruit rot disease of cherry, iron oxide nanoparticles (Fe 2 O 3 NPs) were synthesized in the leaf extract of Calotropis procera and characterized. Fourier transform infrared (FTIR) spectroscopy of synthesized Fe 2 O 3 NPs showed the presence of capping and stabilizing agents such as alcohols, aldehydes, and halo compounds. X-ray diffraction (XRD) analysis verified the form and size (32 nm) of Fe 2 O 3 NPs. Scanning electron microscopy (SEM) revealed the spinal-shaped morphology of synthesized Fe 2 O 3 NPs while X-ray diffraction (EDX) analysis displayed the occurrence of main elements in the samples. After successful preparation and characterization of NPs, their antifungal activity against A. flavus was determined by poison technique. Based on in vitro and in vivo antifungal activity analyses, it was observed that 1.0 mg/mL concentration of Fe 2 O 3 can effectively inhibit the growth of fungal mycelia and decrease the incidence of fruit rot of cherry. The results confirmed ecofriendly fungicidal role of Fe 2 O 3 and suggested that their large-scale application in the field to replace toxic chemical fungicides.