Carrier-free co-delivery nanosystem based on prothioconazole and pyrimethanil to enhance fungicidal efficacy and reduce environmental risks.

Background: The conventional application of fungicides suffers from substantial off-target loss due to photolysis, evaporation, and rain washing, resulting in risks to the environment and human health. To address these limitations, self-assembled nanopesticides based on two kinds of fungicides have emerged as precision agrochemical delivery platforms that synchronize enhanced bioactivity with environmental risk mitigation.

Results: Herein, core-shell structured nanoparticles (PRO-PYR NPs) with an average particle size of 263 nm were fabricated based on prothioconazole (PRO) and pyrimethanil (PYR) via non-covalent interactions using co-assembly technology. The co-delivery system with acid-responsive release property enhanced both antifungal activities against Botrytis cinerea and Fusarium graminearum and duration against Botrytis cinerea. Importantly, the obtained PRO-PYR NPs could significantly improve photostability and foliage adhesion of fungicides and reduce their volatility and leaching potential. Additionally, the PRO-PYR NPs reduced genotoxicity of PRO and PYR to the root tip cells of Vicia faba and acute toxicity to zebrafish.

Conclusion: The core-shell structured nanoparticles based on two commonly used fungicides were successfully prepared by co-assembly technology to effectively improve the physicochemical properties. Carrier-free co-delivery strategy based on multiple components of fungicides could effectively enhance the control effect and lower the negative impacts associated with non-target organisms and environment for integrated pest management. © 2025 Society of Chemical Industry.