A biodegradable kasugamycin prodrug nanosystem for precise fungicide delivery and sustained disease control

BACKGROUND: The poor stability and limited efficacy of biopesticides remain major bottlenecks restricting their widespread application. Herein, dual stimuli-responsive kasugamycin (KAS) prodrug nanoparticles (DAS NPs) were constructed via self-assembly by conjugating KAS with dialdehyde cellulose (DAC) through dynamic Schiff-base bonds. RESULTS: The resulting DAS NPs exhibited a small particle size, negative zeta potential and low critical micelle concentration, which improved the wettability, photostability and dilution stability of the active ingredient on rice leaves. In vitro release experiments showed rapid responsiveness of DAS NPs to acidic pH and cellulase, leading to the cleavage of dynamic Schiff-base bonds and controlled release of KAS. The nanosystem exhibited remarkable antifungal activity against rice blast in both glasshouse and field trials, effectively controlling the disease and prolonging the residual activity of KAS. Moreover, DAS NPs exhibited superior performance compared with the commercial KAS aqueous formulation in reducing rice yield losses caused by blast infection. Biological safety evaluations further confirmed excellent compatibility of DAS NPs with rice plants, aquatic organisms and soil ecosystems. CONCLUSION: This work provides field-scale validation of DAS NPs via self-assembly strategy, demonstrating substantial improvements in disease control efficacy, crop yield and grain quality. The dual stimuli-responsive design improves pesticide utilization efficiency and offers an environmentally sustainable strategy for plant disease management. © 2026 Society of Chemical Industry.