Pectin-coated hollow organosilicon construction of a dual pH and pectinase stimulation-responsive prochloraz delivery system for the control of rice sheath blight

BACKGROUND Rice sheath blight, caused by Rhizoctonia solani ( R. solani) poses a significant threat to global rice production. Although prochloraz (PRO) is an effective fungicide, its poor photostability and low water solubility severely limit its field performance. We developed a sustainable, stimuli-responsive delivery system to enhance PRO efficacy and minimize environmental risks. RESULTS Multilayered mesoporous nanoparticles (MSN@PMO) were synthesized via a hard-template route and converted into hollow periodic mesoporous organosilicas (H-PMO) by sodium carbonate etching. PRO was encapsulated in H-PMO and sealed with pectin, yielding a dual pH/pectinase responsive formulation (Pec@PRO-H-PMO, PPHP). PPHP exhibited sustained release for 144 h under acidic and enzymatic conditions, and showed markedly improved photostability, foliar adhesion and rainfastness compared with PRO technical concentrate (PRO TC) and PRO water emulsion (PRO EW). Bioassays demonstrated that PPHP exhibited 1.8 times greater antifungal activity against R. solani compared to PRO TC. Ecotoxicological analysis revealed 11.9 times higher zebrafish median lethal concentration (LC₅₀) values than PRO TC over 80% viability of human bronchial epithelial (BEAS-2B) cells at 18.4 mg/L, suggesting improved biosafety. CONCLUSIONS The dual pH/pectinase triggered release of PPHP enhanced pesticide utilization and improved safety. This strategy presents a novel approach for developing stimuli-responsive pesticide delivery systems, aiming to strengthen crop disease control efficiency and mitigate environmental risks. © 2025 Society of Chemical Industry.