The present study describes the biosynthesis of silver nanoparticles, using the fungus
Penicillium verrucosum
. The silver nanoparticles were synthesised by reacting silver nitrate (AgNO
3
) with the cell free filtrates of the fungal culture, and were then characterized by UV–visible spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive, and X-ray diffraction analysis to further evaluate their successful biosynthesis, optical and morphological features (size and shape), and crystallinity. The bioactivity of the synthesized nanoparticles against two phytopathogenic fungi i.e:
Fusarium chlamydosporum
and
Aspergillus flavus
was evaluated using nanomaterial seeding media. These biogenic silver nanoparticles were polydisperse in nature, with a size of 10–12 nm. With regard to the antifungal activity, 150 ppm of the nanoparticles suppressed the growth of
F. chlamydosporum
and
A. flavus
by about 50%. To the best of our knowledge, this is the first report on the use of
P. verrucosum
to synthesise silver nanoparticles. The present study demonstrates a novel, simple, and eco-friendly process for the generation of biofunctionally useful biogenic nanoparticles.