This study aimed to synthesize silver nanoparticles (AgNPs) by pomegranate and orange
peel extracts using a low concentration of AgNO3 solution to controlearly blight of tomato caused by
Alternaria solani. The pathogen was isolated from infected tomato plants growing in different areas of
Saudi Arabia. The isolates of this pathogen were morphologically and molecularly identified. Extracts
from peels of pomegranate and orange fruits effectively developed a simple, quick, eco-friendly and
economical method through a synthesis of AgNPs as antifungal agents against A. solani. Phenolic
content in the pomegranate peel extract was greater than orange peel extract. Phenolic compounds
showed a variation of both peel extracts as identified and quantified by High-Performance Liquid
Chromatography. The phenolic composition displayed variability as the pomegranate peel extract
exhibited an exorbitant amount of Quercitrin (23.62 mg/g DW), while orange peel extract recorded
a high amount of Chlorogenic acid (5.92 mg/g DW). Biosynthesized AgNPs were characterized
using UV- visible spectroscopy which recorded an average wavelength of 437 nm and 450 nm for
pomegranate and orange peels, respectively. Fourier-transform infrared spectroscopy exhibited
32x73.24, 2223.71, 2047.29 and 1972.46 cm􀀀1, and 3260.70, 1634.62, 1376.62 and 1243.76 cm􀀀1 for
pomegranate and orange peels, respectively. Transmission electron microscopy showed spherical
shape of nanoparticles. Zetasizer analysis presented negative charge values; 􀀀16.9 and 􀀀19.5 mV
with average particle sizes 8 and 14 nm fin case of pomegranate and orange peels, respectively.
In vitro, antifungal assay was done to estimate the possibility of biosynthesized AgNPs and crude
extracts of fruit peels to reduce the mycelial growth of A. solani. AgNPs displayed more fungal
mycelial inhibition than crude extracts of two peels and AgNO3. We recommend the use of AgNPs
synthesized from fruit peels for controlling fungal plant pathogens and may be applied broadly and
safely in place by using the chemical fungicides, which display high toxicity for humans.