Introduced Pests Outreach Project

Potato Wart

(Click on an image below to see the captioned full-size version)
Figure 1
Figure 2
Figure 3

Scientific Name: Synchytrium endobioticum

Common Name: Potato Wart

Known Hosts:
The primary cultivated host is potato (Solanum tuberosum). Also infects wild hosts in the genus Solanum.

The only above ground symptom that may be noticeable is a reduction in vigor. Only symptoms below ground are apparent.
Rough, warty growths at the base of the stems (Figure 1).
Eyes develop into warty, cauliflower-like outgrowths that can be cut more easily than the tuber.
Growths are white below ground, green when exposed to light, and darken with age.
The warts range from the size of a pea to large masses that cover the entire tuber (Figure 2).

Similar disease or symptoms:
Powdery scab
See the University of Maine Cooperative Extension Bulletin # 2436, Powdery Scab of Potatoes, for a description of symptoms.

Fact sheets and references:
APHIS Pest Detection and Management

NAPIS- Links for information on potato wart

North American Plant Protection Organization Phytosanitary Alert System

Canadian Food Inspection Agency: Information on biology, distribution, and identification of potato wart symptoms

United Kingdom Department for Environment, Food and Rural Affairs: Descriptions and photos of symptoms and information on measures taken against potato wart in the UK

Data Sheet on Potato Wart from EPPO: Contains information on hosts, biology, distribution, detection and identification, means of movement and dispersal, and phytosanitary measures

Hooker, W.J., editor. 1981. Compendium of Potato Diseases. American Phytopathological Society. St. Paul, Minnesota, USA.

Rich, A.E. 1983 Potato Disease. Academic Press, New York, New York.

last reviewed December 30, 2014

Massachusetts Department of Agricultural Resources
The Massachusetts Introduced Pests Outreach Project is maintained by staff at the Massachusetts Dept. of Agricultural Resources. This website was made possible, in part, by a Cooperative Agreement from the United States Department of Agriculture's Animal and Plant Health Inspection Service (USDA APHIS). It may not necessarily express APHIS' views.