Bacterial Ring Rot: Yet another devastating disease of potato

Ring Rot Symptoms

Ring rot is primarily a disease of stored tubers and seed potatoes, where it produces black or brown lines just below the surface of the potato. As the disease progresses, these lines will extend and thicken as the potato rots from the inside out. This most often happens during storage but can also happen in the field if plants are infected at the start of the season. If infected during the growing season, potato plants do not always show signs of disease. If present, symptoms tend to mimic other wilts and develop wilting, yellowing, leaf rolling, and dieback. Infected tubers can cause entire batches of seed potatoes to be rejected or rot entire harvests over the winter during storage. Ring rot is difficult to identify since it mimics many other diseases, both in tubers and plants. Other diseases and conditions that resemble ring rot that are present in South Dakota include Potato Leafroll Virus, Verticillium Wilt, Potato Virus Y, and Charcoal Rot, as well as freezing damage in stored tubers.