Select resistant soybean varieties to manage disease
Plants affected by brown stem rot will have some root rot, but it won’t be as extensive as plants with SDS where the root system will have a deteriorated tap-root and lateral roots will only be evident in the upper soil profile. Plants will typically pull easily and there may be a dark blue fungal growth on the roots with SDS. Plants affected by brown stem rot will not have root rot symptoms.
Split the Stems. With any root and stem rot disease it is critical that you split the stems to accurately identify the disease. This is particularly true when trying to differentiate between SDS and brown stem rot. With SDS the center of the stem will not be discolored; discoloration will be confined to the outer stem layers. The root cortex also will be discolored — a light-gray to brown — and may extend up the stem. Brown stem rot will discolor the center of the stem and typically will be brown from the soil line going up. Examination of the split stem may show discoloration starting at the nodes.
Variety selection will be your best option for managing both BSR and SDS. Fields with high levels of SDS should not be planted early in future years and should be managed to reduce compactions. Fields with brown stem rot will benefit from longer rotations, but fields with SDS will not be affected by rotation.