Comparative efficacy of silver nanoparticles from agro-industrial waste of cumin, anise, and banana peel against Fusarium oxysporum on common bean (Phaseolus vulgaris)

Abstract Fusarium oxysporum , the causal agent of root rot and vascular wilt in common bean ( Phaseolus vulgaris ), represents a substantial risk to legume cultivation. The current study offers a comparative examination of the antifungal efficacy of agro-industrial wastes from cumin ( Cuminum cyminum ), anise ( Pimpinella anisum ), and banana peel ( Musa paradisiaca ), and their green-synthesized silver nanoparticles (AgNPs), against F. oxysporum infecting P. vulgaris . The biosynthesized AgNPs were found to be spherical with tiny sizes ranging from 20, 25, and 35 nm for cumin-AgNPs, anise-AgNPs, and banana peel-AgNPs, respectively. The agro-industrial waste extracts revealed a diverse range of bioactive compounds that served as reducing agents. In vitro antifungal activity revealed a dose-dependent suppression of F. oxysporum mycelial proliferation. The half-maximal effective concentrations (EC 50 ) for the crude extracts ranged from 125 to 200 µg/mL. AgNPs showed markedly improved EC 50 values, ranging from 62.5 µg/mL in cumin-AgNPs to 100 µg/mL in banana-AgNPs. In vivo greenhouse experiments on infected P. vulgaris demonstrated that all treatments significantly decreased disease severity. Soil drench application of agro-industrial waste extracts reduced disease severity to 59.64% (cumin waste), 66.52% (anise waste), and 74.86% (banana peel), compared with 85.14% in the infected control. The AgNPs fabricated from agro-industrial wastes offered enhanced protection, decreased disease severity to 36.17% (cumin-AgNPs), 43.30% (anise-AgNPs), and 51.52% (banana peel-AgNPs). The applications significantly alleviated the physiological and oxidative stress caused by F. oxysporum . The cumin-AgNPs treatment significantly restored chlorophyll a and chlorophyll b content to 2.45 and 0.92 mg/g, respectively, comparable to the healthy control (2.50 and 0.95 mg/g) and much higher than the infected control (1.10 and 0.40 mg/g). Moreover, it triggered a defense response, markedly enhancing the activities of antioxidant enzymes, including peroxidase and polyphenol oxidase, in the treated plant compared with the infected control. The current findings clearly indicate that AgNPs synthesized from agro-industrial wastes could serve as effective, sustainable nanobiopesticides, surpassing the use of a single agro-industrial waste for the integrated management of Fusarium root rot and vascular wilt in common beans.