The presence of dark brown or reddish lesions on the stem and lower main root confirms seedling disease. Microscopic examination of the damaged tissue is sometimes necessary to identify specific disease pathogens involved. Southern stem blight damages a wide range of host plants, including soybeans. The fungus is most active during summer, and survives in the soil and on plant debris. Soybean losses to the disease vary considerably, but generally the damage occurs as localized areas of dead plants scattered across fields.
Economic losses occur in some instances.
Pod and stem blight occurs in every soybean-producing area of the United States and in many foreign countries. It is usually a late season disease, favored by warm, humid weather. It is a major cause of seed damage which results in poor seed quality. The fungus lives from season to season on seed or on crop residue. The most characteristic symptom of this disease is the arrangement of black fruiting structures in linear rows on the stems.