Tunable Release Poly(butylene oxalate) Fungicide Nanocarrier for Long-Term Fusarium Crown Rot Management

The design of intelligent pesticide delivery systems based on the characteristics of soil-borne diseases is of great significance for improving pesticide utilization efficiency and achieving long-lasting disease control. Herein, a cost-effective and degradable functional poly(butylene oxalate) (PBO) material was constructed and applied for the encapsulation of metconazole (MEZ) to develop a sustained-release pesticide delivery system (MEZ@PBO). The optimized MEZ@PBO was mainly distributed within the 200-300 nm range, with a fungicide-loading capacity reaching 55.7%. Release experiments confirmed the regulatory effect of the PBO molecular weight on the release rate, with higher molecular weight resulting in a longer sustained release period, thereby prolonging the duration of efficacy. MEZ@PBO significantly enhances the photostability of the fungicide while preventing pesticide loss caused by leaching. Moreover, pot experiments indicated that MEZ@PBO achieved long-lasting control of the Fusarium crown rot. After 14 days, the inhibition rate against Fusarium crown rot was 37.9 and 22.4% higher than those of the metconazole technical material and commercial formulation, respectively. Biosafety evaluation and degradation tests further confirmed the environmental friendliness and crop safety. This work offers a promising strategy for enhancing the stability, release control, and efficacy of fungicides in sustainable agriculture.