Efficacy of <i>Azadirachta indica</i> Extract and the Green Synthesized Silver Nanoparticles Against the <i>Aspergillus</i> spp. Causing Pomegranate Fruit Rot in Taif Governorate, Saudi Arabia

Despite being prone to fungal diseases, particularly those caused by Aspergillus species, the pomegranate fruit is greatly esteemed for its nutritional value and health benefits. Fungal infections can inflict significant damage and may produce mycotoxins, which pose serious risks to human health. Species of Aspergillus are responsible for causing diseases that affect pomegranate fruit in Taif, Saudi Arabia. This study aims to assess the efficacy of neem extract and its silver nanoparticles as antifungal agents against these infections. Upon reviewing their morphological and genetic traits, the predominant species identified were Aspergillus niger, Aspergillus versicolor and Aspergillus tubingensis. Laboratory-based studies indicate that neem extract, administered at a dose of 5000 ppm, inhibited the growth of fungal colonies by as much as 56.25%. The antifungal effectiveness of silver nanoparticles derived from neem extract showed considerable improvement. Applying neem-silver nanoparticles resulted in a 76.6% increase in growth inhibition, while disease pathogenicity decreased on artificially inoculated fruits from 55.83% in the control to 0.00% in A. versicolor when tested at the concentration of 5000 ppm. The ethanol-based neem nanoparticles effectively halted the formation of A. niger fungal spores at a radius of 7 mm, in contrast to the 33 mm observed in the control. Evidence suggests that neem-based formulations, particularly those that are nano-formulated, could serve as a viable alternative to synthetic fungicides. This study is unique in evaluating the antifungal efficacy of neem crude extract and its green synthesized silver nanoparticles in managing pomegranate fungal diseases in Taif region. Therefore, it provides new evidence that natural bio-fungicides can extend the shelf life of food and reduce the environmental impact associated with chemical farming practices.