The development of resistance in phytopathogenic fungi to conventional fungicides, coupled with escalating environmental and health concerns, necessitates the development of eco-compatible next-generation antifungal agents. This study presents the development and evaluation of novel biopolymer-based metallic-chitosan‑copper-β-glucan (CN-Cu-BG) tri-element nanocomposite (NC) synthesized via microwave-assisted methods. Detailed nanomaterial characterizations confirm the formation of uniformly spherical NCs (~41.97 nm) with integrated copper signatures indicative of successful composite formation. These embedded copper nanoparticles (Cu-NPs) within a dual biopolymer matrix have enhanced antifungal efficacy, plant immune response and yield-promoting effects. In-vitro antifungal assays against Sclerotium rolfsii (causal agent of sugarbeet root rot) and Cercospora longipes (causal agent of sugarcane brown spot) revealed complete mycelial growth inhibition at a concentration as low as 200 ppm of the CN-Cu-BG NC. Foliar application of CN-Cu-BG NC at 50 ppm in sugarbeet increased chitinase and β-glucanase activities by 673% and 681%, respectively and boosted chlorophyll content by 72%. Beet weight improved by 80%, with a 74% disease control. Multivariate analyses identified PPO, β-glucanase, chitinase and chlorophyll as key markers associated with enhanced disease control (r = 0.84-0.94). Heatmap, PCA and PLS-DA confirmed the superior performance of CN-Cu-BG NC at 50 ppm across biochemical, physiological and yield parameters. These findings demonstrate CN-Cu-BG NC as a scalable, eco-compatible nanobiopolymer offering a potent alternative to chemical fungicides, integrating nanobiotechnology with sustainable crop protection and circular bioeconomy practices.
Chavanke et al. (Fri,) studied this question.