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Late Blight

Scientific Name

Phytophthora infestans (Montagne) Bary (ITIS)

Common Name

Late blight (LB), late blight disease, potato late blight, tomato late blight


Peronospora infestans Montagne (ITIS)

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.

Late blight symptoms on Tomato -
Image use policy

Symptoms of late blight on tomato Florida Department of Agriculture and Consumer Service. Division of Plant Industry.

Find more images


  • 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 - Outbreak Map

    • USDA. National Institute of Food and Agriculture.

    • View Outbreak Map for current year or for prior years.


Selected Resources

The section below contains highly relevant resources for this species, organized by source.

International Government
State and Local Government