Potato diseases include infestations of the root, leaves and tubers caused by bacteria, fungi and other viruses. Common potato diseases include potato wart, soft rot and potato blight, according to the American Phytopathological Society. A complete list of potato diseases can be found on the U.S. Department of Agriculture website.
In the 1840s, potato blight swept through many parts of Europe, with severe infestations eliminating the crop altogether in many regions, states the United States Potato Board. As the dietary staple disappeared in Ireland, an estimated one million succumbed to starvation or disease and just as many left the country for the United States and Canada.