Home › Plant diseases › Early blight

Plant diseases

Early blight

Alternaria solani and Alternaria linariae · Fungus

Also called target spot (Australia).

Illustration

Brown spots with target-like rings on the oldest, lowest leaves of tomatoes and potatoes, spreading upwards. Removing the lower leaves, mulching and good spacing slow it down.

How to spot it

• Brown-black spots on the oldest, lowest leaves first.
• Spots about 1 cm across, with concentric 'bullseye' rings and a yellow halo.
• Spots merging, and the lower leaves dying.
• Dark, sunken, ringed spots on fruit; dark sunken patches on potato tubers.

Easily confused with

Where it's a problem

• Australia: Common, and often called target spot (in the USA, target spot is a different tomato disease).
• North America: Common.
• United Kingdom: Not a common problem in British gardens.

What to do

1. Use clean seed and healthy seedlings.
2. Space plants for airflow.
3. Mulch to stop soil splashing onto the leaves, and water at the base.
4. Remove the lowest leaves, then any infected ones.
5. Rotate crops, keeping tomatoes and potatoes out of the same bed for 2–3 years or more.

If you use a fungicide, choose one labelled for early blight and follow the label and local rules. Sprays only protect, and work best started before symptoms appear.

Follow your local council's guidance for disposing of diseased plant material.

Free account, no card needed. You sign up or sign in first, then the scanner opens.

Sources

• University of Maryland Extension: Early blight of tomatoes
• Clemson University HGIC: Tomato diseases and disorders
• Pacific Pests, Pathogens and Weeds: Tomato early blight
• University of Wisconsin–Madison Extension: Early blight
• University of California IPM: Early blight

Facts checked Sunday 27 September 2026. General guidance only: follow your local council, agency and product label.