Symptoms include the absence of bolls or abortion of immature bolls, and affected plants often grow vigorously. During late flowering, leaves may show potassium deficiency or yellowing with leaves often cupping upward and slightly reddening around the margin of the upper leaves. These foliar symptoms do not occur all the time. The most important above ground symptom is the lack of bolls on the plant. Sometimes, affected roots have blackened galls, which range from 1 mm to several cm wide.
Black root is more common in flatwood soils but has been observed in other soil types.
The problem is most common south of Tifton from Thomas County east to Wayne County and as far north as Appling County. The cause of the disorder is unknown and is currently under investigation. It is important that you notify your county Extension agent to confirm this problem. Cotton Nematode Sampling . It is time to consider sampling for cotton nematodes.