Plant-mediated synthesis of silver nanoparticles from Vinca rosea and their application against wheat pathogenic fungi

This study reports an eco-friendly, sustainable approach to synthesizing silver nanoparticles (Ag NPs) using Vinca rosea L. (Catharanthus roseus) leaf extract. The plant extract served as a natural reducing and stabilizing agent, eliminating the need for hazardous chemicals. Formation of Ag NPs was confirmed by UV–visible spectroscopy, which showed a characteristic surface plasmon resonance peak at 425 nm, while scanning electron microscopy (SEM) revealed predominantly cubical nanoparticles with sizes ranging from 48 to 67 nm. The antifungal efficacy of the biosynthesized Ag NPs was evaluated against two major wheat pathogens, Fusarium graminearum and Bipolaris sorokiniana, using the poisoned food technique at concentrations of 125–1000 µg/mL. The Ag NPs exhibited strong, dose-dependent antifungal activity against F. graminearum and B. sorokiniana compared with the aqueous extract at 1000 µg/mL, with ED50 values of 65 and 70 µg/mL, respectively. In contrast, the aqueous leaf extract showed comparatively lower inhibition, with ED50 values of 173 µg/mL for F. graminearum and 156 µg/mL for B. sorokiniana. The antifungal performance of the Ag NPs was comparable to that of the commercial fungicide propiconazole (Tilt 25 EC). The enhanced activity of the Ag NPs is attributed to their nanoscale size, high surface reactivity, and synergistic interaction between silver ions and plant-derived phytochemicals. These findings demonstrate that V. rosea-mediated Ag NPs represent a cost-effective, scalable, and environmentally benign alternative to synthetic fungicides, with promising applications in sustainable agriculture and plant disease management.