Efficient and environment-friendly nanopesticide delivery systems are critical for the sustainable development of agriculture. In this study, a graphene oxide nanocomposite was developed for pesticide delivery and plant protection with pyraclostrobin as the model pesticide. First, graphene oxide–pyraclostrobin nanocomposite was prepared through fast adsorption of pyraclostrobin onto graphene oxide with a maximum loading of 87.04%. The as-prepared graphene oxide–pyraclostrobin nanocomposite exhibited high stability during two years of storage, suggesting its high potential in practical application. The graphene oxide–pyraclostrobin nanocomposite could achieve temperature (25 °C, 30 °C and 35 °C) and pH (5, 7 and 9) slow-release behavior, which overcomes the burst release of conventional pyraclostrobin formulation. Furthermore, graphene oxide–pyraclostrobin nanocomposite exhibited considerable antifungal activities against Fusarium graminearum and Sclerotinia sclerotiorum both in vitro and in vivo. The cotoxicity factor assay revealed that there was a synergistic interaction when graphene oxide and pyraclostrobin were combined at the ratio of 1:1 against the mycelial growth of Fusarium graminearum and Sclerotinia sclerotiorum with co-toxicity coefficient values exceeding 100 in vitro. The control efficacy of graphene oxide–pyraclostrobin nanocomposite was 71.35% and 62.32% against Fusarium graminearum and Sclerotinia sclerotiorum in greenhouse, respectively, which was higher than that of single graphene oxide and pyraclostrobin. In general, the present study provides a candidate nanoformulation for pathogenic fungal control in plants, and may also expand the application of graphene oxide materials in controlling plant fungal pathogens and sustainable agriculture.

Plant pathogens constantly develop resistance to antimicrobial agents, and this poses great challenges to plant protection. Therefore, there is a pressing need to search for new antimicrobials. The combined use of antimicrobial agents with different antifungal mechanisms has been recognized as a promising approach to manage plant diseases. Graphene oxide (GO) is a newly emerging and highly promising antimicrobial agent against various plant pathogens in agricultural science. In this study, the inhibitory activity of GO combined with fungicides (Mancozeb, Cyproconazol and Difenoconazole) against Fusarium graminearum was investigated in vivo and in vitro. The results revealed that the combination of GO and fungicides has significant synergistic inhibitory effects on the mycelial growth, mycelial biomass and spore germination of F. graminearum relative to single fungicides. The magnitude of synergy was found to depend on the ratio of GO and fungicide in the composite. In field tests, GO–fungicides could significantly reduce the disease incidence and disease severity, exhibiting a significantly improved control efficacy on F. graminearum. The strong synergistic activity of GO with existing fungicides demonstrates the great application potential of GO in pest management.

Nanopesticides with controlled release can achieve more effective utilization of pesticides. Here, to enhance the adsorption of pesticides onto the target organisms, the formulation of pesticides with temperature-responsive release was proposed by combing graphene oxide (GO) and existing pyrethroid pesticides (cyhalothrin, bifenthrin and fenpropathrin). Pesticides were loaded onto GO nanosheets as a carrier via a simple physisorption process, and the GO–pesticide nanocomposites exhibited temperature-responsive release and excellent storage stability, which are of vital importance to the practical application. Furthermore, we assessed the bioactivity of the GO–pesticide nanocomposites against spider mites (Tetranychus urticae Koch) indoors and in the field. As a result, GO–pesticide nanocomposites had many folds higher bioactivity than individual pesticides, and could be adsorbed on the cuticle of T. urticae and surface of bean leaves with highly uniform dispersibility. The easy preparation and higher bioactivity of GO–pesticide nanocomposites indicate their promising application potential in pest control and green agriculture.

The wheat scab caused by Fusarium graminearum (F. graminearum) has seriously affected the yield and quality of wheat in China. In this study, gallic acid (GA), a natural polyphenol, was used to synthesize three azole-modified gallic acid derivatives (AGAs1–3). The antifungal activity of GA and its derivatives against F. graminearum was studied through mycelial growth rate experiments and field efficacy experiments. The results of the mycelial growth rate test showed that the EC₅₀ of AGAs–2 was 0.49 mg/mL, and that of AGAs–3 was 0.42 mg/mL. The biological activity of AGAs–3 on F. graminearum is significantly better than that of GA. The results of field efficacy tests showed that AGAs–2 and AGAs–3 significantly reduced the incidence rate and disease index of wheat scab, and the control effect reached 68.86% and 72.11%, respectively. In addition, preliminary investigation was performed on the possible interaction between AGAs–3 and F. graminearum using density functional theory (DFT). These results indicate that compound AGAs–3, because of its characteristic of imidazolium salts, has potential for use as a green and environmentally friendly plant-derived antifungal agent for plant pathogenic fungi.

Shigella dysenteriae is a highly pathogenic microorganism that can cause human bacillary dysentery by contaminating food and drinking water. This study investigated the antibacterial activity of chestnut bur polyphenol extract (CBPE) on S. dysenteriae and the underlying mechanism. The results showed that the minimum inhibitory concentration (MIC) of CBPE for S. dysenteriae was 0.4 mg/mL, and the minimum bactericidal concentration (MBC) was 1.6 mg/mL. CBPE treatment irreversibly disrupted cell morphology, decreased cell activity, and increased cell membrane permeability, cell membrane depolarization, and cell content leakage of S. dysenteriae, indicating that CBPE has obvious destructive effects on the cell membrane and cell wall of S. dysenteriae. Combined transcriptomic and metabolomics analysis revealed that CBPE inhibits S. dysenteriae by interfering with ABC protein transport, sulfur metabolism, purine metabolism, amino acid metabolism, glycerophospholipid metabolism, and some other pathways. These findings provide a theoretical basis for the prevention and treatment of S. dysenteriae infection with extract from chestnut burs.