It is necessary to explore eco-friendly antimicrobial agents to resolve problems such as pathogen resistance and pesticide residues. In this study, Mentha haplocalyx leaf extract was applied to biosynthesize nano silver using a microwave-assisted method. The detailed properties of the nano silver were systematically revealed by several analytical methods. The antifungal activity of nano silver and synergistic antifungal effects of nano silver conjugated with pesticides against Curvularia lunata were determined. Pathogen invasion was significantly inhibited (57.3%) on detached and intravital maize leaves when the concentration of nano silver was 200 μg mL⁻¹, with an inhibition zone diameter of 12.5 ± 1.18 mm. In addition, a clear synergistic antifungal effect of nano silver conjugated with epoxiconazole was observed at volume ratios of 8:2 and 9:1, while the toxicity ratios were 1.18 and 1.11, respectively. These results not only provide a new avenue for pathogen management, but also enable reduced dosages of antibiotics and pesticides to mitigate or avoid emergence of drug-resistant pathogens.

Synergistic antifungal activity of biosynthesized silver nanoparticles combined with mancozeb against Botryosphaeria dothidea was carried out. Indexes of colony growth, colony formation, and inhibition zone were measured to reveal their antifungal effect. The results showed that silver nanoparticles synthesized by llexchinensis Sims leaf were near spherical with the average size of 14 nm. The inhibition rate and diameter of inhibition zone reached 81.9% and 12.6 ± 1.25 mm when the concentration of silver nanoparticles was 200 μg/mL. In addition, distinct synergistic antifungal activity was detected when silver nanoparticles were combined with mancozeb at the volume ratios of 1:9 and 8:2, and the toxic ratio was 1.32 and 1.14, respectively. As one kind of non-antibiotic bacteriostatic substances, silver nanoparticles would be substitute or supplement with fungicide to resolve pesticide residue and pathogen resistance that plagued agricultural for a long time.

Synthesis of metal nanoparticles through biological method becomes more and more prevalent owing to its incomparable advantages. Eco-friendly silver nanoparticles (AgNPs) were synthesized by Cinnamomum camphora leaf extract through microwave, and spectrophotometry was applied to determine the optimalbiosynthesis process. It contained 20 ml of leaf extract, 4 mM AgNO₃, and pH seven over medium-high heat. TEM images displayed that synthesized AgNPs were near spherical and roughly in the range of 6–32 nm. Such synthesized AgNPs exhibited prominent antimicrobial activity against Rhizoctonia solani. The inhibition rate of colony growth and the diameter of inhibition zone reached 81.7% and 20.5 mm when the concentration of AgNPs was 200 μg/mL.The initial results provide a new idea and method for integrative control of phytopathogens, and it’s likely to resolve the perplexing problems in agricultural production.