DISEASES OF SOYBEAN - BROWN SPOT

Brown spot is a disease that, in Wisconsin, has little direct impact on soybean growth and productivity. The disease is caused by the fungus Septoria glycines and is characterized by small, irregularly shaped spots or lesions on soybean leaves. These spots may enlarge and merge to form necrotic blotches. Although brown spot rarely causes yield losses on its own in Wisconsin, the disease can be an indicator of other disease problems or environmental stresses. Therefore, if you see symptoms of brown spot, check the plants for other pathogens. In particular, check for the presence of soil-borne pathogens such as Phytophthora sojae or the soybean cyst nematode, Heterodera glycines.