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Posted 06 September 2007. PMN Crop News.

New Resources from MSU Help Growers Identify, Control Potato Diseases

Michigan State University.

East Lansing, Michigan (August 22, 2007)--Managing and controlling potato diseases is a complex task for growers, but thanks to efforts by plant pathologists at Michigan State University (MSU), their job has gotten a bit easier. Farmers now have access to eight bulletins, a pocket-sized scouting guide and a Web site that they can refer to for help in identifying and controlling potato diseases.


Willie Kirk and Phill Wharton, plant pathologists at MSU, developed the Web site,, and scouting guide, “A Pocket Guide to Disease Scouting in Michigan Potatoes” (bulletin E-2998), as reference tools to help farmers identify common potato diseases in Michigan. “Our goal is to provide the state’s potato growers with the science-based information they need to make decisions to control and prevent potato diseases,” Wharton said. The scouting guide was developed as a pocket reference text for use in disease scouting in potato fields. It includes lists of the basic symptoms for each disease, photos, a description of disease cycles, and details on how to distinguish between diseases with similar symptoms. When growers detect disease symptoms in their crop, they can refer to the scouting guide to make a preliminary disease diagnosis. They should then send a plant sample to the MSU Center for Plant Diagnostic Services or to their local county MSU Extension office to confirm disease identification. “Hopefully, the scouting guide will help farmers make preliminary diagnoses of any diseases that may exist in their fields,” Wharton said. “Growers should use the guide in combination with the bulletins, which have detailed information on each disease and suggest recommended cultural, biological and chemical control options. “It is important to identify diseases at an early stage because several diseases may have similar-looking symptoms. For example, foliar lesions of gray mold and early blight -- controllable diseases in Michigan -- have similar-looking lesions to late blight, a very serious disease that may result in the loss of an entire crop if it’s not caught early,” he said. “It’s important to be able to distinguish between the lesions of these three diseases because immediate action needs to be taken if late blight is discovered in a potato field.” Growers may refer to the bulletins or the Web site for control options once a disease is confirmed in their fields. Wharton said the Web site is basically an electronic version of the printed bulletins. It provides up-to-date recommendations, news, alerts and the same basic information as the scouting guide. The eight bulletins are: “Late Blight” (bulletin E-2945), “White Mold” (E-2989), “Common Scab of Potato” (E-2990), “Early Blight” (E-2991), “Fusarium Dry Rot” (E-2992), “Pink Rot” (E-2993), “Rhizoctonia Stem Canker and Black Scurf of Potato” (E-2994) and “Potato Seed Health Management” (E-2995). The late blight bulletin costs $2; the others cost $1.50 each. The scouting guide, “A Pocket Guide to Disease Scouting in Michigan Potatoes” (E-2998), costs $10 per copy. Bulletins can be downloaded as PDFs at or purchased through the MSU Bulletin Office, The research conducted by Kirk and Wharton that appears in the bulletins and on the Web site received funding from Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs), Michigan’s plant agriculture initiative at MSU. Production of the Web site was also funded by Project GREEEN. Founded in 1997, Project GREEEN is a cooperative effort between plant-based commodities and businesses together with the Michigan Agricultural Experiment Station, MSU Extension and the Michigan Department of Agriculture to advance Michigan’s economy through its plant-based agriculture. Its mission is to develop research and educational programs in response to industry needs, ensure and improve food safety, and protect and preserve the quality of the environment. To learn more about Michigan’s plant agriculture initiative at MSU, visit

Sara Long
517-432-1555, ext. 170