By M. Putnam
Cause The soilborne fungus Verticillium dahliae. The relationship of the strains of V. dahliae that affect ginseng to the Verticillium diseases of other crops such as potatoes has not been determined. The fungus grows into the xylem where it colonizes the plant through mycelial growth and conidial production. Fluid movement in the xylem passively transports the conidia. Once in the xylem, this fungus partially blocks water movement and produces toxins that result in wilt symptoms.
Symptoms Foliar symptoms are premature reddening or yellowing, or wilting while green. Vascular tissue in affected roots is discolored a dark brown to black, which appears as a dark ring in cross-section.
Sampling Send soil samples to any of various private and public laboratories to assay for Verticillium propagules.
Cultural control
- Do not plant on land known to be infested with Verticillium.
- Do not track soil from infested areas into clean areas. Clean boots, equipment, and tools before leaving an infested area.
- Rotate with weed-free alfalfa or cereal crops.
Chemical control Preplant fumigation with metam-sodium reduced inoculum levels in the soil but did not prevent the pathogen from being reintroduced via soil from infected areas.
Reference Murthy, H.N., Dalawai, D., Park, S.Y., and Paek, K.Y. 2018. Endophytes of Ginseng. In, Endophytes and Secondary Metabolites. Reference Series in Phytochemistry. Springer, Cham.