Fabrication a controlled-release pesticide for improving UV-shielding properties and reducing toxicity via coating polydopamine

Controlled-release formulations (CRFs) have potential applications in modern agriculture, for it can not only prolong the duration of agrochemicals but also alleviate the adverse effect on non-target organism. In this study, we constructed pyraclostrobin@SiO2@polydopamine microcapsule (Pyr@SiO2@PDA MC). The resulting microcapsule is a near-rod shape (about 1.15 μm), which has a drug-loading efficiency of 55%. Fourier transform infrared (FTIR) and thermogravimetric analysis (TG) revealed the successful entrapment of the pesticide. The coating of polydopamine (PDA) endowing the microcapsule with superior UV-shielding properties than pyraclostrobin@SiO2 microcapsule (Pyr@SiO2 MC). Compared with pyraclostrobin emulsifiable concentrate (EC), the Pyr@SiO2@PDA MC exhibited 9.07-, 5.50-, 4.93- and 4.16-fold higher fungicidal activity against Rice blast fungus (Pyricularia oryzae) at concentrations of 0.5, 1, 2 and 4 mg/L. Moreover, acute toxicity tests demonstrated that the sample on zebrafish with lower toxicity on the first day. These results showed that the obtained microcapsule may process broader application potential in agriculture.