Common Tomato Diseases and Disorders
Diseases
Late Blight—Phytophthora infestans
** Late Blight is a very serious disease. If you suspect Late Blight in your garden, please contact the University of Maine Cooperative Extension, Pest Management Office at 800-287-0279 **
Brown, leathery spots on the top and sides of fruit. In humid conditions, white mold also forms.
Spots start out pale green, usually near the edges of tips, then turn brown to purplish-black. In humid conditions a fuzzy mold appears on the undersides of leaves.
Black and brown spots appear and spread. In high humidity, entire vines can be killed very quickly.
Early Blight—Alternaria solani
Dark, sunken spots on the stem end of fruits.
One or two spots per leaf, each ¼ to ½ inch diameter. Spots have tan centers with concentric rings and yellow halos.
Dark, sunken cankers at or above the soil line.
Anthracnose—Colletotrichum coccodes
Depressed, circular lesions up to 5 inches in diameter on ripe fruit.
As lesions mature, they develop concentric rings and become dotted with small black specks.
In moist weather, masses of salmon-colored spores may form on the lesion surface.
Bacterial Spot—Xanthomonas campestris
Fruit lesions start as tiny raised blisters.
Lesions increase in size and become brown and scab-like.
On leaves, stems and fruits, brown circular lesions, less than 1/10 inch in diameter.
Bacterial Canker—Clavibacter michiganensis
Distinctive spots are white and slightly raised initially, then raised with dark-colored center and white halos, each about 1/16 inch in diameter. The white halo later turns brown.
Leaflets begin to turn brown at the edges, then die back progressively toward the leaf midrib.
Often only one side of a plant is affected at first, but symptoms eventually spread.
Tomato Leaf Spot—Septoria lycopersici
Fruit is not affected, although sunscald can be a problem due to foliage loss.
Numerous brown spots on leaves, each about 1/16 inch in diameter. They do not have a yellow halo and they do have black specks in the center.
First symptoms are usually on lower leaves after the first fruit sets. Disease spreads from oldest to youngest growth.
White Mold (Sclerotinia stem rot)—Sclerotinia sclerotiorum
Fruit is not affected. Infected stems are soft with a light gray bleached appearance.
White mold appears on plants during flowering.
Hard, black sclerotia with white interiors form inside stems.
Physiological
Blossom End Rot
First appears as a sunken, brownish black spot ½ to 1 inch in diameter at the blossom end of the fruit.
Spots gradually increase in size.
Blossom end rot is caused by a calcium deficiency related to fluctuations in available moisture.
Sunscald
Occurs on green tomato fruit exposed to the sun.
Initially a whitish shiny area, the bleached tissues gradually collapse, forming a slightly sunken area that may become pale yellowish and wrinkled as the fruit ripens.
The killed tissue is invaded by secondary organisms which cause the fruit to decay.
Catfacing
Misshapen fruit with irregular bulges at the blossom end and bands of leathery scar tissue.
Catfacing is caused by cold weather at the time of blossom set.
Catfacing is most common in the large-fruited "beefsteak" type tomatoes.
Fruit Cracking
Cracking is due to rapid fruit development and wide fluctuations in water availablity.
Radial growth cracks radiate from the stem.
Concentric cracks encircle the fruit, usually on the shoulders.
Click on images to view full-size
Identification and Control Information
- Tomato Diseases and Disorders (includes information on most of those listed) [PDF]—Iowa State University Extension
- Tomato Leaf and Fruit Diseases and Disorders (includes information on many of those listed plus others) [PDF]—Kansas State University Cooperative Extension
- Recognizing Tomato Problems (PDF)—Colorado State University Extension
Late Blight
- Late Blight of Potato and Tomato: Resources and Alerts—University of Massachusetts Extension
- Late Blight on Tomato—Cornell University, Long Island Horticultural Research & Extension Center
- Late Blight Management for Fall, Winter and Spring (PDF)—University of Massachusetts Extension
- Gardening After Late Blight (PDF)—University of Maine Cooperative Extension
- Late Blight of Potato and Tomato (PDF)—Maryland Cooperative Extension
- Late Blight: A Serious Disease of Potatoes and Tomatoes (PDF)—Cornell University Cooperative Extension
- Information about Tomato Late Blight including Organic Products—North Carolina State University Cooperative Extension
- Fact Sheet with Symptoms and Management Strategies—Cornell University
- Managing Late Blight in Tomato and Potato–An Essential Part of Gardening (PDF)—Cornell University
- Late Blight: Frequently Asked Questions by Gardeners, Growers & Consumers (PDF)—Cornell University
Early Blight
- Tomato Disorders: Early Blight and Septoria Leaf Spot (PDF)—University of Wisconsin Extension
- Early Blight of Tomato (PDF)—University of Maine Cooperative Extension
- Early Blight of Tomatoes (PDF)—Virginia Cooperative Extension
- Early Blight on Tomatoes and Potatoes (PDF)—Florida Cooperative Extension Service
- Early Blight and Septoria Leaf Spot of Tomato (PDF)—Cornell University Cooperative Extension
Anthracnose
- Anthracnose of Tomatoes (PDF)—The Ohio State University Extension
- Anthracnose of Tomatoes (PDF)—AVRDC–The World Vegetable Center
Bacterial Spot and Bacterial Canker
- Bacterial Canker of Tomato (PDF)—University of Kentucky Cooperative Extension Service
Tomato Leaf Spot (Septoria)
- Septoria Leaf Spot of Tomato (PDF)—University of Maine Cooperative Extension
- Tomato Disorders: Early Blight and Septoria Leaf Spot (PDF)—University of Wisconsin Extension
- Early Blight and Septoria Leaf Spot of Tomato (PDF)—Cornell University Cooperative Extension
- Septoria Leaf Spot of Tomatoes (PDF)—The Ohio State University Extension
- Early Blight and Septoria Leaf Spot of Tomato (PDF)—Cornell University Cooperative Extension
White Mold
- Pest Management: White Mold of Vegetables (PDF)—University of Maine Cooperative Extension
Blossom End Rot
- Blossom-End Rot of Tomato, Pepper, and Eggplant (PDF)—The Ohio State University Extension
- Blossom End Rot of Tomatoes and Other Vegetables (PDF)—South Dakota State University Cooperative Extension Service
- Tomatoes: Blossom End Rot, Sunscald, Catfacing (PDF)—Oklahoma State University Cooperative Extension Service
- Plant Disease Control: Tomato Blossom-end Rot—Oregon State University Extension
Sunscald
- Tomato Disorders: Sunscald (PDF)—AVRDC–The World Vegetable Center
- Tomatoes: Blossom End Rot, Sunscald, Catfacing (PDF)—Oklahoma State University Cooperative Extension Service
Catfacing
- Catfacing (PDF)—AVRDC–The World Vegetable Center
- Tomatoes: Blossom End Rot, Sunscald, Catfacing (PDF)—Oklahoma State University Cooperative Extension Service
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[Photos, left to right: Robert Wick, University of Massachusetts, Bugwood.org; Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org; Department of Horticulture Website at Cornell University; Yuan-Min Shen, Taichung District Agricultural Research and Extension Station, Bugwood.org; Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org; Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org; USDA; Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org; Apsnet.org; Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org; Ufl.edu; Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org; Heinz USA Archive, Bugwood.org; Heinz USA Archive, Bugwood.org; UMass Extension; MU Extension Plant Diagnostic Clinic; William M. Brown Jr., Bugwood.org; ISU Plant Disease Clinic; Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org; Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org; Iowa State University Extension; Tim Coolong, University of Kentucky; Patrick Byers, MU Extension; Howard F. Schwartz, Colorado State University, Bugwood.org; Queen's Printer for Ontario, 2009; Queen's Printer for Ontario, 2009; M.E. Bartolo, Bugwood.org; Queen's Printer for Ontario, 2009; Univ of California Extension; Texas AgriLife Extension Service, Texas A&M System; Paul Bachi, University of Kentucky Research & Education Center, Bugwood.org ]