A biodegradable oxidized starch/carboxymethyl chitosan film coated with pesticide-loaded ZIF-8 for tomato fusarium wilt control.

Film mulching is one of the most important methods to control soil-borne diseases. However, the traditional mulch may cause microplastic pollution and soil ecological damage. Herein, a biodegradable film was developed using oxidized starch and carboxymethyl chitosan and incorporated ZIF-8 carrying fludioxonil to sustainably control soil-borne disease. The microstructure, mechanical properties, optical properties, and water barrier properties of the composite films (Flu@ZIF-8-OS/CMCS) were investigated. The results show that Flu@ZIF-8-OS/CMCS had a smooth and uniform surface and excellent light transmittance. The excellent mechanical properties of the films were verified by tensile strength, elongation at break and Young's modulus. Higher contact angle and lower water vapor permeability indicate water retention capacity of the soil was improved through using Flu@ZIF-8-OS/CMCS. Furthermore, the release properties, biological activity, degradability and safety to soil organisms of Flu@ZIF-8-OS/CMCS was determined. The addition of ZIF-8 significantly improved the film's ability to retard the release of Flu, while the Flu@ZIF-8-OS/CMCS has good soil degradability. In vitro antifungal assays and pot experiments demonstrated excellent inhibitory activity against Fusarium oxysporum f. sp. Lycopersici. Flu@ZIF-8-OS/CMCS caused only 13.33 % mortality of earthworms within 7 d. This research provides a new approach to reducing microplastic pollution and effectively managing soil-borne diseases.

Sodium alginate-carboxymethyl chitosan hydrogels loaded with difenoconazole for pH-responsive release to control wheat crown rot.

Increasing concern about environmental pollution has driven the development of controlled release formulations for agrochemicals. Due to the advantages of degradability and responsiveness to environmental stimuli, polysaccharide-based hydrogel is an ideal carrier for agrochemicals controlled release. In this study, a method-easy polysaccharide hydrogel for controlled release of difenoconazole (DZ) was prepared with sodium alginate (SA) and carboxymethyl chitosan (CMCS). Due to its three-dimensional crosslinked mesh structure, the prepared hydrogels (CSDZ) showed an agrochemical load capacity of 9.03 % and an encapsulation efficiency of 68.64 %. The release rate is faster in alkaline solution, followed by neutral solution, and slowest in an acid environment, which is consistent with the swelling behavior. Furthermore, leaching studies showed that CSDZ hydrogels have excellent protective properties for encapsulated agrochemicals. Compared with technical DZ, the results of in vitro and pot antifungal testing showed that CSDZ had a better control effect against wheat crown rot (Fusarium pseudograminearum). Safety assessment studies indicated that CSDZ hydrogels exhibit good biocompatibility on nontargeted organisms (Daphnia magna, zebrafish and Eisenia fetida) and wheat. This study aims to provide a potentially promising approach for the preparation and application of biocompatible polysaccharide-based hydrogels for agrochemical-controlled release in sustainable disease management.

Preparation and Characterization of a Novel Artemisia Oil Packaging Film and Its Application in Mango Preservation.

In this work, a new food packaging film was synthesized via blending Artemisia oil (AO) into soybean protein isolate (SPI) and gelatin (Gel) for the postharvest storage of mango. The morphological architecture and mechanical properties of the films were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and other technologies. The results show that the prepared films had relatively flat surfaces with good mechanical properties. AO enhanced the light-blocking ability of the film, increased the hydrophobicity, and affected the moisture content and water solubility of the film to a certain extent. Furthermore, the antioxidant performance and antifungal (Colletotrichum gloeosporioides) capacity of the films increased with higher AO concentration due to the presence of the active components contained in AO. During mango storage applications, the films showed good freshness retention properties. The above results indicate that SPI-Gel films containing AO have excellent physicochemical and application properties and have great potential in the field of food packaging.

Construction of Fe3O4/xSiO2/ySiO2 Nanoparticles for Pesticide Removal from Water: Improved Dispersion Stability and Adsorption Capacity.

Highly efficient and reusable adsorbents for pesticide removal from wastewater have received increasing attention. In this study, Fe3O4 was synthesized using the solvothermal method. Fe3O4/xSiO2 and Fe3O4/xSiO2/ySiO2 were obtained through layer-by-layer silica (SiO2) coating on the surface of Fe3O4. SiO2 coating improved the dispersibility of the adsorbent, which can be separated from water rapidly under the action of the external magnetic field. The adsorption capacity of the adsorbent was investigated through removing pyraclostrobin from synthetic wastewater. The adsorbent showed the highest adsorption effect at the adsorbent concentration of 1 mg mL-1, at a pH of 7, and the adsorbent time of 110 min. The fitting model of the adsorption process conformed to the second-order kinetic model and the Langmuir model. The maximum adsorption capacity of Fe3O4/xSiO2/ySiO2 nanoparticles was 94.89 mg g-1, and the removal efficiency was about 96% at adsorption equilibrium. Acetone as the eluent can effectively desorb the adsorbent, and the desorbed adsorbent had high reusability. Particularly, the removal efficiency was still greater than 86% after 9 times of reuse. These results provide a reference for designing reusable nanoparticles to effectively absorb pesticides in wastewater.

Construction and formulation optimization of prothioconazole nanoemulsions for the control of Fusarium graminearum: Enhancing activity and reducing toxicity.

In this study, the optimal emulsifier for prothioconazole nanoemulsions was initially screened based on appearance, microscopic observation, mean droplet size and polydispersity index (PDI). In addition, the BoxBehnken design method is adopted, and the optimal formula is screened with an emulsification time, emulsifier content, and solvent content as a single factor. On this basis, the nanoemulsion meets FAO standards for various indicators. The contact angle of droplets on wheat leaves was significantly reduced. This nanoemulsion also showed good inhibitory activity against Fusarium graminearum (EC50 =1.94 mg L-1), low acute toxicity to zebrafish (LC50 =26.35 mg L-1) and good biosafety to BEAS-2B cells. The nanoemulsion reduced the adverse effects of pesticide on wheat seed germination and growth. This study can help promote the design and manufacture of stable, efficient and safe agricultural nanoemulsions, and is expected to benefit the sustainable development of green plant protection.