Typical symptoms of Rhizoctonia root rot are reddish brown lesions on stems along the soil line. Symptoms of Fusarium root rot are dark discolorations, although some Fusarium species also can cause reddish brown discoloration on soybean roots. Usually, plants can grow out of root rot problems and symptoms disappear as the season progresses into late July and August. Under severe infection, which is rare, infected plants wilt and die in patches. Root rot damage caused by Rhizoctonia and Fusarium can be reduced by cultivation.
Cultivation mounds soil around the base of soybean plants, which promotes new growth of roots.
However, if the growth conditions are not good for quick recovery, root rot problems may occur after midsummer. Note fields with severe root rot and consider using seed treatment when growing the next soybean crop. There are no resistant varieties available to Rhizcotonia root rot and Fusarium root rot. Keep in mind that factors other than fungi could be causing the root problems or interacting with root rot fungi. Stresses such as iron chlorosis, herbicide injury, potassium deficiency, and even minor hail injury can weaken plants, making them more susceptible to pathogenic soilborne fungi.