Soybeans were scouted at the R4 (full pod) growth stage and yellowing/brown discoloration of leaves and wilt were observed in patches across the field. Samples were taken and the issue was confirmed by the NC State Plant, Disease and Insect clinic to be Cercospora Leaf & Stem Blight. This is a foliar disease that is caused by the pathogen Cercospora kikuchii, also the causal agent of purple seed stain. While common in soybeans, this disease rarely causes significant yield losses for North Carolina producers.
Crop rotation with non-host crops such as small grains or corn may help reduce pathogen loads in crop residue. Tillage can also help reduce pathogen loads. Fungicides might reduce observed disease, but they have not been shown to reduce the incidence of purple seed stain.
