Evaluation of the Antifungal and Biochemical Activities of Fungicides and Biological Agents against Ginseng Sclerotinia Root Rot Caused by Sclerotinia nivalis

The objective of this study was to identify effective agents for the prevention and control of ginseng <i>Sclerotinia</i> root rot disease caused by <i>Sclerotinia nivalis</i>. The inhibitory effects of 16 chemical fungicides and 10 biocontrol agents (strains) on mycelial growth and sclerotium formation in <i>S. nivalis</i> were determined using a plate confrontation essay. The results showed that the best chemical agents for inhibiting the mycelial growth and sclerotium formation of <i>S. nivalis</i> were fluconazole and fludioxonil, while <i>Bacillus amyloliquefaciens</i> FS6 and <i>B. subtilis</i> (Kono) were the best biocontrol agents (strains). The results of field trials in 2022 and 2023 showed that the control effects of fluconazole and fludioxonil on ginseng <i>Sclerotinia</i> root rot disease were 90.60-98.16%, and those of the biocontrol agents <i>B. amyloliquefaciens</i> FS6 and <i>B. subtilis</i> (Kono) were 94.80-97.24%, respectively. Chemical agents produced abnormal and twisted mycelia, while the biocontrol agents increased mycelial branching, dilated the mycelium tip, and revealed an abnormal balloon. All of the fungicides decreased the ergosterol content, changed the cell membrane permeability, and increased the protein and nucleic acid permeability. These results suggest that these are potential agents for controlling ginseng <i>Sclerotinia</i> root rot disease, and their biochemical mechanisms of chemical and biocontrol of this disease were demonstrated.