B-1032

Potato Late Blight

By Gary Franc, Cooperative Extension Service Plant Pathologist,

University of Wyoming,

William Brown, Jr., Cooperative Extension Service Plant Pathologist,

Colorado State University, and

Eric Kerr, Cooperative Extension Service Plant Pathologist,

University of Nebraska

Late blight is a fungal disease that comes from infected seed tubers, potato cull piles, and volunteer potatoes. Epidemics are initiated by fungal spores produced on living, infected plant tissue. Spores are spread by rain, overhead irrigation, and wind. Pictures of various stages are shown along with a disease-cycle chart. A list of least and most-resistant potato varieties is given.