Cornell UniversityCollege of Agriculture and Life Sciences
Department of Horticulture
Department of Plant Pathology
  and Plant-Microbe Biology

Department of Entomology
CCE of Suffolk County
Long Island Horticultural Research and Education Center
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Serving the research and extension needs
of Long Island's horticultural industries.


Vegetable Pathology contact:

Dr. Meg McGrath
mtm3@cornell.edu
3059 Sound Ave.
Riverhead, NY 11901
(631) 727-3595
(631) 727-3611 (fax)

All photographs in this gallery were taken by Meg McGrath unless otherwise noted. For permission to use Meg's, please email her: mtm3@cornell.edu
 

Early blight of tomatoes

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The main symptom of early blight is round leaf spots with a characteristic target appearance due to the dark concentric rings that develop in most spots. They are about .5 inch in diameter. Spots first appear on older leaves near the base of the plant. The causal fungal pathogen also produces symptoms on stems and fruit. Young seedlings can be killed by stem lesions developing at their base. Sources of the pathogen are infested seed, debris from infected plants left in or on the soil (where it can survive at least 1 year), and spores from other affected plants dispersed typically short distances by wind, water, insects, or animals.

Below: Early blight symptoms first appear on older leaves near the base of the plant.

early blight on tomato

Below: Tomato leaves infected with early blight.

early blight on tomato

Below: Note the 'target' appearance of concentric rings. The causal fungus can also cause symptoms on stems and fruit.

early blight on tomato

Below: Early blight on tomato stem.

early blight on tomato

Below: Symptoms of early blight on fruit calyx and stem.

early blight on tomato

Return to disease photo index.


Copyright by the Department of Horticulture Website at Cornell University.