Early Blight - Vegetables

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Early blight is a very common foliar disease of tomato plants that can result in defoliation and reduced yields. It can also infect eggplant. The fungus overwinters in soil and plant debris and can also be transmitted on seed and transplants. Early blight is typically splashed by rainfall onto lower leaves early in the season. Infections begin as small brown spots on older leaves that quickly enlarge. A yellow halo usually surrounds the lesions. The lesions develop a "bulls-eye" pattern of concentric rings that can be seen with a hand lens. Individual lesions enlarge and coalesce and can kill entire leaves. The disease can also move to stems and fruits and produce dark lesions. When leaves die, fruits become more vulnerable to sunscald. Infected, dead leaves may stick to fruits. The disease can spread during wet or dry weather but is favored by rainfall and heavy dews. The disease spores are wind-blown, allowing the disease to spread through a garden or neighborhood.

Click an image to enlarge

early blight on tomato fruit early blight spots on leaf close up of lesion
Early blight symptoms on fruit
Early blight spots on foliage
Close-up of lesion with bulls-eye pattern
early blight on tomato plant early blight lesions with yellow spots
Late stage symptoms on tomato plant
Lesions with yellow halo on foliage

Management:

If early blight is a persistent problem:

  1. Select resistant varieties of tomato.
  2. Monitor transplants carefully for signs of this disease.
  3. Keep plants well mulched to minimize soil splashing.
  4. Provide adequate spacing to increase air circulation and remove all suckers that emerge from the plant base.
  5. Remove and destroy badly infected lower leaves to slow the upward spread of the disease.
  6. Rogue out badly infected plants and remove infected plant debris at the end of the season.
  7. Apply a chemical fungicide or an organic fungicide (fixed copper) according to label directions, early in the season, when symptoms appear to slow the spread of the disease. This may be helpful where the disease causes severe blighting each year leading to reduced yields.
  8. Diseased plant parts can be shredded and composted if "hot composting" techniques are used (pile temperatures should exceed 120° F throughout and piles should be turned two to three times).
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