Chitosan-Copper Hybrid Nanoflowers: A Novel Nanopesticide for Controlling <i>Rhizoctonia solani</i> Infection in Crops

Copper-based nanomaterials are effective alternatives to traditional pesticides due to their antibacterial properties. However, the high cost and low dispersity limit their application. In this study, we synthesized cost-effective, eco-friendly, and stable chitosan-copper hybrid nanoflowers (CS-Cu HNFs) through facile self-assembly to manage agricultural diseases caused by the fungal pathogen (<i>Rhizoctonia solani</i>). The results show that CS-Cu HNFs, which utilized chitosan and copper phosphate as primary scaffolds, were formed via a series of nucleation, aggregation, self-assembly, and anisotropic growth processes. 200 mg/L CS-Cu HNFs exhibited an excellent inhibitory effect on <i>R. solani</i>, which was 6.11 times that of CuO nanoparticles, despite CS-Cu HNFs containing only 45% of Cu as that in CuO nanoparticles. Additionally, CS-Cu HNFs significantly reduced <i>R. solani</i> infection in various crops and displayed broad-spectrum antibacterial activity. This research provides new insights into the preparation and application of organic-inorganic hybrid nanoflowers as nanopesticides.