If soil is wet, Phytophthora may continue to develop on the soybean stem, resulting in chocolate brown discoloration from the soil line up, a unique symptom of this disease. Soybean seedling disease caused by Rhizoctonia exhibits different symptoms from those caused by Phytophthora . Seedling blight by Rhizoctonia normally appears when the weather becomes warm. Unlike Phytophthora damping-off, stem discoloration by Rhizoctonia is usually limited to the cortical layer of the main root and hypocotyl. Infected stems remain firm and dry.
Root rot is visible on severely infected plants.
Enlarge Seedling disease by Rhizoctonia . This season, replanting from severe damping-off may be rare. If replanting is needed, you can avoid disease damage in the replanted soybeans by considering seed treatment to reduce the risk of further damping-off. Use seed treatments that contain Apron because it is effective against Phytophthora , and Rival or Maxim because they are effective in controlling Rhizoctonia . Also, take disease notes for future use.