Southern blight causes a gradual wilting of the plant, and the plant eventually dies without changing color. The fungus girdles the stem at the soil line and a large brown irregular lesion is visible there. The lesion is covered by a whitish mat of fungus, and small, spherical, orange/tan colored fruiting bodies (scelerotia) are visible on the lesion.
High temperature and wet conditions promote the disease. Spores can survive in the soil for several years. Good sanitation (including removing and burning infected plants), extended crop rotations, and careful water management are key elements in controlling this disease.