Soybeans planted in cold, wet soil are most susceptible to infection by Pythium . If a disease occurs in warm conditions, it is more likely caused by Phytophthora . Rhizoctonia and Fusarium also can cause seedling diseases. Seedling diseases from these fungi are different than those caused by Pythium and Phytophthora . Seedling blight by Rhizoctonia normally appears when warm weather begins to arrive.
Infected stems remain firm and dry.
The reddish-brown color is a good symptom to aid in diagnosing the disease. Compared with other fungi, Fusarium is a minor problem in Iowa, causing about 10 percent of seedling blight problems each year. If replanting must be done, follow these guidelines to avoid further disease damage. Work the ground to provide a better seed bed, especially if the first planting is in no-till ground. For seed rot, there are no above-ground symptoms to determine which fungus is causing the problem.