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Dextran has emerged as a promising biopolymer carrier for controlled release formulations of pesticides. In this study, pH-sensitive acetalated dextran microparticles (Pyr@Ac-Dex) are prepared to encapsulate and control the release of pyraclostrobin (Pyr). In vitro fungicidal activity experiments showed that the prepared Pyr@Ac-Dex particles show comparable fungicidal ability against S. sclerotiorum compared to that of Pyr technical. In a 10-day pot experiment, the control efficacy of the Pyr@Ac-Dex treatment against S. sclerotiorum (77.1%) is significantly higher than that of Pyr emulsifiable concentrate (Pyr EC) treatment (42.4%). Photodegradation experiments show that compared to Pyr technical, Pyr@Ac-Dex doubles the half-life of Pyr in water. Acute toxicity experiments show that Pyr@Ac-Dex significantly reduced the acute exposure toxicity of Pyr to zebrafish. This study provides an environmentally friendly, feasible, and sustainable strategy for plant disease management. [Display omitted] [ABSTRACT FROM AUTHOR]

Lignin sulfonate (LS), a waste material from the paper pulping, was modified with benzoic anhydride to obtain benzoylated lignin sulfonates of adjustable hydrophilicity (BLS). When BLS was combined with difenoconazole (Di), a broad-spectrum fungicide, lignin-based, non-crosslinked nanoparticles were obtained either by solvent exchange or solvent evaporation. When a mass ratio of 1:5 LS: benzoic anhydride was used, the Di release from Di@BLS 5 after 1248 h was ca. 74 %, while a commercial difenoconazole microemulsion (Di ME) reached 100 % already after 96 h, proving the sustained release from the lignin nanocarriers. The formulation of Di in lignin-based nanocarriers also improved the UV stability and the foliar retention of Di compared to the commercial formulation of the fungicide. Bioactivity assay showed that Di@BLS 5 exhibited high activities and duration against strawberry anthracnose (Colletotrichum gloeosporioides). Overall, the construction of fungicide delivery nano-platform using BLS via a simple non-crosslinked approach is a novel and promising way to develop new formulations for nanopesticide and the development of sustainable agriculture. [Display omitted] [ABSTRACT FROM AUTHOR]