Infected plants are less vigorous and have smaller leaves than healthy plants. Leaves turn yellow and wilt. Eventually leaves turn brown and have a dry appearance. The taproot and lower stem develop a gray to silvery discoloration of the epidermis (outer layer of the soybean stem). The epidermis may flake or shred away from the stem, giving the stems a tattered appearance. Internal stem and taproot tissues are reddish brown and become grayish black at maturity. When the epidermis is removed, numerous small, black microsclerotia are present.

Charcoal rot appears in hot, dry weather or after other stress conditions. The fungus survives in crop debris and has a wide host range including both corn and grain sorghum. Reducing stress factors and rotating to cereals, cotton or other nonhosts for one to two years aid in control.