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National Invasive Species Information Center
U.S. Department of Agriculture
Home / Terrestrial Invasives / Terrestrial Pathogens and Diseases / Late Blight

Late Blight

View all resources
Late blight symptoms on Tomato - Invasive.org
Symptoms of late blight on tomato Florida Department of Agriculture and Consumer Service. Division of Plant Industry.
Scientific Name: 
Phytophthora infestans (Montagne) Bary (ITIS)
Synonym: 
Peronospora infestans Montagne (ITIS)
Common Name: 
Late blight (LB), late blight disease, potato late blight, tomato late blight
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)
Impact: 
Disease of potatoes and tomatoes (Fry and Goodwin 1997)
Current U.S. Distribution: 
Occurs throughout the U.S.

Spotlights

Announcing IDphy: A Tool for Phytophthora Identification (Sep 30, 2019)

USDA. APHIS. PPQ. CPHST. Identification Technology Program.

ITP and the APHIS PPQ S&T Beltsville Lab are pleased to announce the release of IDphy: Molecular and Morphological Identification of Phytopthora Based on the Types, ITP’s first pathogen tool. This website offers PPQ and its partners the most complete, valid, and up-to-date resource for identifying the culturable species of Phytophthora. IDphy includes detailed standard operating procedures for all steps involved in culturing, sequencing, and identifying suspect samples, covering both molecular and morphological methods. Some species of Phytophthora are devastating plant pathogens that have a significant impact on agriculture and natural ecosystems.

USAblight - A National Project on Tomato & Potato Late Blight in the United States
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.

Distribution / Maps / Survey Status

USAblight - Occurrence Map: Late Blight Map
USDA. National Institute of Food and Agriculture.

Images

Google Images - Late Blight
Google.
Invasive.org - Late Blight
University of Georgia. Center for Invasive Species and Ecosystem Health.

Videos

YouTube - What You Need to Know
Google. YouTube; Pennsylvania State University Outreach.

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.

Partnership
Invasive Species Compendium - Phytophthora infestans
CAB International.
New York Invasive Species Information - Late Blight

New York Invasive Species Clearinghouse.

Plantwise Technical Factsheet - Phytophthora Blight (Phytophthora infestans)
CABI. Plantwise Knowledge Bank.
International Government
Late Blight of Potato and Tomato (Mar 2016) (PDF | 292 KB)
British Columbia Ministry of Agriculture (Canada).
See also: Field Vegetables for more fact sheets.
Integrated Management of Late Blight in Potatoes

Manitoba Agriculture, Food and Rural Development (Canada).

State and Local Government
Late Blight of Tomato and Potato in Connecticut (Jun 2014) (PDF | 812 KB)
Connecticut Agricultural Experiment Station.
See also: Plants: Fruits, Vegetables, Flowers, and House Plants Fact Sheets for more resources
Academic
Potato Pest Management Guidelines - Late Blight (Mar 2019)

University of California. Statewide Integrated Pest Management Program.

Late Blight of Tomato and Potato (2018)

Virginia Tech; Virginia State University. Virginia Cooperative Extension.

Late Blight in Alaska (Revised Dec 2017) (PDF | 856 KB)

University of Alaska - Fairbanks. Cooperative Extension Service.

See also: UAF/CES Publications for more fact sheets.
Late Blight in Potato (May 2017)
North Dakota State University. Extension Service; University of Minnesota Extension.
Vegetable Diseases: Late Blight of Tomato and Potato (Feb 2010)
Purdue University (Indiana). Extension.
Insects, Pests, and Diseases: Tomato-Potato Late Blight in the Home Garden (2009)

Pennsylvania State University. Cooperative Extension.

Late Blight of Tomato (Phytophthora infestans) (Aug 2008) (PDF | 593 KB)
University of Hawaii. Cooperative Extension Service.
See also: Plant Disease Publications for more fact sheets.
Crop Knowledge Master - Phytophthora infestans
University of Hawaii. Tropical Agriculture and Human Resources. Integrated Pest Management Program.
Fact Sheets: Diseases - Late Blight and Tomato Transplant Production
University of Massachusetts - Amherst. UMass Extension. Greenhouse Crops & Floriculture Program.
Pacific Northwest Plant Disease Management Handbook - Potato (Solanum tuberosum)-Late Blight
Oregon State University. Extension Service.
Pest Alerts for Vegetables - Late Blight Information

Cornell University. New York State Integrated Pest Management Program.

Professional
Organic Alternatives for Late Blight Control in Potatoes (Mar 2004)
National Center for Appropriate Technology. National Sustainable Agriculture Information Service.
Combating Light Blight
International Potato Center.
Plant Disease Lessons - Late Blight of Potato and Tomato
American Phytopathological Society.

Citations