How to Recognize, Manage and Prevent Early Blight on Tomato, Potato, Eggplant and Other Wild Plants

An example of early blight on tomato stems...
An example of early blight on tomato stems...
...and on the actual tomato fruit.
...and on the actual tomato fruit.

Recognizing Early Blight

  • Early blight is a fungus that attacks tomato plants, potato plants, eggplants and other wild plants that are tomato-related. You will think you are seeing spots and a bull's eye when you have early blight, as it appears as small brown to black spots, which are usual oval, but sometimes irregularly shaped.
  • The spots will appear on the leaves and the tissue around the spots may turn yellow. Often, the entire leaf turns yellow. The bull's eye appears when concentric rings in the legion form and appear to be a "target" of sorts.
  • The first leaves to become infected are the oldest and the lowest on the plant. They begin to droop and become very dry. Then, they die.
  • Tubers are also affected by early blight, but not as often as the leaves. The tuber lesions look like dark, sunken spots. Tomatoes that are infected will develop dark and leathery sunken spots near the stem. The spots on tubers are large and may have concentric ridges similar to the ones on infected leaves.

Managing Early Blight Fungus

  • The only way to manage early blight is to get rid of all signs as soon as you see them. Remove and destroy the spotted leaves, and rake and burn the dry vines of the affected plants after harvest has been completed.
  • You might want to spray with a fungicide containing chlorothalonil, but contact the local Cooperative Extension office before you do so because some fungicides are for regional use only, and you just might not be in the right region to use that particular fungicide.
  • DO NOT COMPOST infected tubers.

Preventing Early Blight

  • As you have read in my articles time after time, don't plant the varieties of these plants that are not resistant to the disease that your plants are stuck with. Check with your local Cooperative Extension office if you want to find out which ones are resistant in your zone, or you can use seed potatoes that have been certified as disease free by your state's department of agriculture.
  • Rotate the crops that get early blight with crops that do NOT get early blight. These are some additional tips that will help in your plight to end the blight.
  • Avoid overhead watering
  • Don't water during cool, cloudy conditions
  • Learn proper fertilization techniques
  • Thin the plants so that they receive enough light and air to reach all parts
  • Handle carefully during harvest - fungus can enter through bruises
  • Eliminate weeds as much as possible
  • Clean up! and Destroy all debris!
  • Conditions that are favorable for early blight are times of heavy dew, heavy rain and warm air temperatures. This fungus, Alternaria solani, is more severe toward the end of the growing season. The spores that spread this disease can survive in plant debris for a year or more.


Fried green tomatoes for supper?  I don't think so!
Fried green tomatoes for supper? I don't think so!
Concentric circles like these on the leave of tomato plants are a sign of early blight.
Concentric circles like these on the leave of tomato plants are a sign of early blight.

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Comments 2 comments

Casey White profile image

Casey White 4 years ago from United States Author

Thank you for stopping by. Sometimes we all just need a little nudge to keep us going in the right direction with our plants.


chspublish profile image

chspublish 4 years ago from Ireland

Very good advice, because I have to admit I can be quite careless and your well-laid out hub is more than reminding me to keep watch and do the right things. Good growing!

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