potato diseases
Although Indiana is not known for potato production, there are several large-scale potato producers in Indiana. For the most part, these producers have their fields scouted (production is mostly for processing) and diseases are managed accordingly. I do occasionally get questions about diseases and the entries below are the result. Diseases which are well known and relatively easily managed may not be reported here. An example would be early blight which must certainly occur on potato, but I have no photos from Indiana.
Black leg
Blackleg of potato-Often the first symptom one might notice is the wilt and collapse of potato plants. Upon closer examination, the stems of such plants may be dark and slimy. These symptoms may extend down into the roots and into the seed potato. Two genera may be responsible for this disease in the Midwest: Pectosporium and Dickeya. The latter genus used to be regulated.
Figure 1. Often the first symptom of black leg of potato that is noticed is a wilt. 
Figure 2. Initial symptoms of black leg of potato. 
Figure 3. The base of the stem of potato plants affected with black leg is often dark and slimy. 
Figure 4. Base of potato plant affected with black leg. 
Figure 5. Collapse, wilt and dark stems caused by black leg of potato. 
Figure 6. Black leg of potato. 
Figure 7. Dark, slimy stem of potato plant with black leg. 
Figure 8. Black leg of potato may affect only occasional plants. At least initially. Late blight
Late blight of potato-I have little experience with this disease. In fact, the photos below are scanned from 35 mm slides.
Figure 1. View of potato field with late blight. 
Figure 2. Lesion on leaf caused by late blight of potato. 
Figure 3. Lesion on leaf caused by late blight of potato. 
Figure 4. Lesion on leaf caused by late blight of potato. Scab
Scab of potato-affected potatoes may appear to have a warty appearance.
Figure 1. Scab of potato.