Occurrence of Above Ground Fungal Diseases in Major Ginseng Cultivation Regions and Pesticide Resistance Evaluation

Background: Major above-ground fungal diseases of ginseng (including Alternaria blight, gray mold, and anthracnose), promoted by warm and humid conditions, reduce ginseng yield and quality. In this study, we surveyed disease occurrence in 2025 across major ginseng-producing regions in Korea, and evaluated the dominant pathogens and their fungicide resistance.<br/>Methods and Results: We conducted field surveys from May to September in 5–6-year-old ginseng fields in Cheorwon, Yeoncheon, Punggi, Jinan, Geumsan, and Eumseong, using five 3.3-m² plots per region. We defined disease incidence as the proportion of diseased leaves. We first detected Alternaria blight in May, which increased throughout summer. Gray mold occurred sporadically from May to June and increased from July onward. Anthracnose appeared early in the season and became widespread by June. Internal transcribed spacer sequencing of 714 fungal isolates detected similar proportions of Alternaria panax and Alternaria alternata among the Alternaria blight isolates, with regional differences in dominance. Colletotrichum panacicola was the predominant anthracnose isolate, whereas we identified all gray mold isolates as Botrytis cinerea. Fungicide resistance assays indicated that more than 90% of Alternaria spp. and Colletotrichum spp. isolates were resistant to azoxystrobin, and B. cinerea isolates exhibited resistance to polyoxin B and boscalid.<br/>Conclusions: The results of this study highlight early and widespread outbreaks under warm and humid conditions and emphasize the need for integrated region-specific disease management and fungicide resistance management programs.