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Late Blight

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Late blight symptoms on Tomato -
Scientific Name:
Phytophthora infestans (Montagne) Bary (ITIS)
Peronospora infestans Montagne (ITIS)
Common Name:
Late blight (LB), late blight disease, potato late blight, tomato late blight
Symptoms of late blight on tomato Florida Department of Agriculture and Consumer Service. Division of Plant Industry.


  • USDA. National Institute of Food and Agriculture.
    A national cooperative effort (funded by USDA-NIFA) on Late Blight of Tomato and Potato in the U.S. This site serves as an information portal on late blight. You can report disease occurrences, submit a sample online, observe disease occurrence maps, and sign up for text disease alerts. There are also useful links to a decision support system, and information about identification and management of the disease.
Native To:
Possibly Mexico (Fry and Goodwin 1997)
Date of U.S. Introduction:
First appeared in the U.S. in the 1840s; new aggressive strains of the disease were discovered in the 1990s (Fry and Goodwin 1997)
Means of Introduction:
Possibly introduced through infected tomatoes imported from Mexico (Fry and Goodwin 1997)
Disease of potatoes and tomatoes (Fry and Goodwin 1997)
Current U.S. Distribution:
Occurs throughout the U.S.

Distribution/Maps/Survey Status



Selected Resources

The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for Late Blight.

International Government

British Columbia Ministry of Agriculture (Canada).
See also: Field Vegetables for more fact sheets.

Manitoba Agriculture, Food and Rural Development (Canada).

State and Local Government


University of California. Statewide Integrated Pest Management Program.

University of Alaska - Fairbanks. Cooperative Extension Service.

See also: UAF/CES Publications for more fact sheets.
North Dakota State University. Extension Service; University of Minnesota Extension.
Virginia Tech; Virginia State University. Virginia Cooperative Extension.
Purdue University (Indiana). Extension.
University of Hawaii. Cooperative Extension Service.
See also: Plant Disease Publications for more fact sheets.
University of Hawaii. Tropical Agriculture and Human Resources. Integrated Pest Management Program.
University of Massachusetts - Amherst. UMass Extension. Greenhouse Crops & Floriculture Program.

Cornell University. New York State Integrated Pest Management Program.


National Center for Appropriate Technology. National Sustainable Agriculture Information Service.
International Potato Center.
Consultative Group on International Agricultural Research.
American Phytopathological Society.