In order to reduce the usage amount of pesticide fertilizers and protect the natural environment, seed coating agents are receiving increased wide concern. In this study, the active constituent (pesticide) and inactive components (surfactants and film former) of the seed coating agents were screened and optimized by the wet sand processing superfine grinding method. The fungal inhibition test of pesticides showed that thifluzamide, fludioxonil, pyraclostrobin, and difenoconazole have an obvious fungal inhibitory effect on wheat sharp eyespot, take-all, and root rot. LAE-9 and polyacrylamide + carboxymethyl cellulose (CMC) is recommended for the safe surfactant and film former, respectively, based on the seed germination test. Moreover, 6% difenoconazole · fludioxonil flowable concentrate for seed coating (FSC) stimulates the seedling growth of wheat, advances the growth of root, and improves biomass in the field trial, meanwhile, the control efficiency reached above 80%. Thus, we suggested it can be used as an effective seed coating agent for the control of soil-borne diseases in wheat. The seed coating agent has the characteristics of disease prevention, increasing crop yield, and safety of environment, which is of significance in practical application.

Rhizobium is a Gram-negative bacterium, which dissolves minerals, produces growth hormones, promotes root growth, and protects plants from different soil-borne pathogens. In the present study, roots, stalks, and fresh weight of maize (Zea mays L.) were significantly increased after soaking in Bradyrhizobium japonicum compared with the control. Subsequently, transcriptome sequencing results of the whole maize plant soaked in B. japonicum showed that multiple growth and development-related genes were up-regulated more than 100-fold compared to the control. Furthermore, the abundance of plant growth promoting bacteria, such as Acidobacteria Subgroup_6 and Chloroflexi KD4-96, were increased significantly. On the contrary, the abundance of multiple pathogens, such as Curvularia, Fusarium and Mycocentrospora, were significantly decreased. Moreover, inoculation with B. japonicum could inhibit the infection of the pathogen Fusarium graminearum in maize. These results suggest that soaking seeds in B. japonicum may affect the expression of maize growth and development-related genes as the bacteria changes the soil microorganism community structure. These findings may help to expand the application of B. japonicum in crop production and provide new opportunities for food security.

Wheat sharp eyespot is a prevalent soil-borne disease that causes substantial economic losses in agriculture. Metconazole, a new triazole broad-spectrum fungicide, has demonstrated effective control of soil-borne diseases. Multi-walled carbon nanotubes (MWCNTs) are an innovative adsorbent material known for their large surface area and high absorptive capacity. This study identifies MWCNTs as the optimal adsorption material for metconazole, achieving an adsorption rate of 85.27% under optimal conditions (stirring time of 30 min and feeding ratio of 6:1). The optimized formula consists of 1.5% dispersant sodium wood, 1% emulsifier BY-112, 2% AEO-15, 3% glycol, 3% filmogen, and 4% red dyes. A 0.5% MWCNT–metconazole suspension concentrate for seed coating (FSC) significantly enhances the inhibitory effect of metconazole on wheat growth and promotes root development. At the tillering stage, a coating ratio of 1:100 shows a marked impact on wheat growth, and MWCNTs can improve the control effect of metconazole to Rhizoctonia cerealis. This work offers a novel approach for applying metconazole in a wheat suspension concentrate for seed coating.