During seed cutting, bacteria from infected tubers are smeared on the cutting knives and healthy seed pieces then become infected. Ring rot bacteria can survive for five years in dried potato stems and for two years on dry burlap, plastic or plywood surfaces. The bacteria, however, live only a short time in soil and are normally killed between fall and winter if all plant debris is plowed down. Bacterial Soft Rot Bacterial soft rot is a common and often serious storage disease of potatoes. It is caused by the bacterium Erwinia carotovora var.
Infected tubers are slimy and foul smelling.
Bacterial soft rot commonly invades frozen tubers and those that have moisture on the surface. Moisture may condense on cold seed piece that are planted into warm, moist soil and soft rot can develop. Soft rot may also cause rapid and severe breakdown of washed and packaged fresh-market potatoes if they are not completely dried prior to packaging. Early season potatoes with immature skin are most susceptible to this soft rot. Blackleg Blackleg is a common disease of potato plants caused by the bacterium Erwinia carotovora var.