🍅 Tomato How hard it is to control: ★★★☆☆ 3/5

Early blight on tomato

A fungal disease (Alternaria solani, A. alternata) attacking tomato leaves, stems and fruit. The give-away is spots zoned into concentric rings, like a shooting target.

Symptom photos

Early blight — Leaf — lesions zoned in concentric rings — Leaf — lesions zoned in concentric rings Photo: Clemson University - USDA Cooperative Extension Slide Series, licence CC BY 3.0 us

Early blight — Stem — brown lesion covered in spores — Stem — brown lesion covered in spores Photo: Clemson University - USDA Cooperative Extension Slide Series, licence CC BY 3.0 us

Early blight — Leaves — dark spots with a distinct yellow halo — Leaves — dark spots with a distinct yellow halo Photo: Dwight Sipler from Stow, MA, USA, licence CC BY 2.0

Early blight — Fruits — sunken, zoned rot next to the stalk — Fruits — sunken, zoned rot next to the stalk Photo: Michal Maňas, licence CC BY 4.0

Symptoms

Brown spots zoned into concentric rings
Yellow halo around the spots on leaves
Spots appear first on the oldest, lowest leaves
Dark, sunken spots on stalks and at the stem end of the fruit
Leaves drying and dropping from the bottom of the plant upwards

What it does to the crop

Leaf loss and sunscald on the exposed fruit
Smaller, poorly colored fruit
Fruit rotting from the stem end
A shorter cropping season

What encourages it

Warm, humid weather at 24-29°C
Leaves alternately wet and dry
Tomatoes grown after tomatoes or potatoes
Plants weakened by nitrogen shortage and drought

Prevention

Rotate with a 3-4 year break for nightshades
Remove lower leaves that touch the soil
Mulch and drip-irrigate without wetting the foliage
Tie plants up so air moves through them
Remove and destroy crop debris after harvest

⚠️ Before you reach for a spray

This atlas is informational and still growing — different diseases can look almost identical. Confirm the diagnosis and read the product label before applying any plant protection product. If you are unsure, ask your local extension or advisory service.

Keep the disease atlas with you in the garden

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