Surfactant-enhanced extension, deposition, and efficient delivery of iron-based metal-organic framework nanoparticles...

Metal-organic framework (MOF) nanocarrier systems have been widely studied for their effectiveness in controlling plant pests and diseases under indoor conditions. However, their field efficacy, environmental degradation dynamics, and biosafety remain insufficiently explored. In this study, we systematically evaluated the wetting properties of eight surfactants on rice leaf surfaces and identified polyethylene glycol octylphenyl ether (TX-100) as the most effective surfactant. TX-100 significantly enhances the adhesion and retention of pectin-coated iron-based metal-organic framework nanoparticles loaded with thifluzamide (TF@Fe-MOF-PT NPs) on rice leaves and stems. Compared to thifluzamide suspension concentrate (TF SC), the TF@Fe-MOF-PT formulation demonstrates superior field efficacy against rice sheath blight (RSB), achieving over 80 % disease control at 21 days post-application. The degradation dynamics of TF@Fe-MOF-PT follow a biphasic pattern: an initial rapid translocation from leaves to roots and stems within the first 10 days, followed by a slow-release phase that ensures prolonged disease suppression. Fluorescent labeling studies reveal that TF@Fe-MOF-PT can be transported upwards through both roots and leaves, accumulating in the glumes via the panicle-neck nodes while avoiding direct transport to the grain. Environmental toxicity assessments indicate that TF@Fe-MOF-PT exhibits significantly lower acute toxicity in adult zebrafish and reduced developmental toxicity in embryos compared to TF SC. High-concentration TF exposure induces severe intestinal apoptosis in adult zebrafish and embryonic malformations. In summary, this study highlights the advantages of using the TF@Fe-MOF-PT nanodelivery system in combination with TX-100 at the superhydrophobic interface of rice leaves. This approach enhances pesticide efficacy, prolongs its persistence, and improves safety.