Different Kinds of Tomato Blight and How to Tell Them Apart

At least two common tomato problems are referred to as tomato blight and another one is often thrown into the same mix: early blight, late blight, and Septoria leaf spot.

3 most common types of tomato blight with Tomato Dirt

They’re each caused by different funguses. You can tell these three problems apart by what they look like, what parts of the tomato they affect, and when their symptoms appear. But the good news is this: all three can be treated and controlled similarly with biofungicides or fungicides and by practicing good preventative care.

  Early Blight Late Blight Septoria
Photo

Photo: University of Minnesota Extension


Photo: Iowa State University


Photo: Cornell University

Cause fungus: Alternaria solani fungus: Phytophthora infestans fungus: Septoria lycopersici
Characteristics Dark, concentric spots ¼ - ½” on lower leaves and stems

Spots on fruit near stems

Lower leaves yellow and drop
Blue-gray spots on leaves which turn brown

Dropped leaves

Irregular brown, greasy spots on fruit

White mold rings on spots

Small black or brown spots on the lower leaves

Lower leaves yellow and drop
Parts affected leaves
stem
fruit
leaves
stem
fruit
leaves
stem
Timing early- to mid-season

in wet weather
mid- to late-season

in wet weather
early- to mid-season

in wet weather



Tomato problems from diseases

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How to identify and treat late blight ...

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Tomato hornworm: how to identify and control it ...

Tomato worms-cutworms: keep them away with stem collars ...

Stink bugs: how to identify and control them on tomato plants...


Tomato problems from growing conditions

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Why a tomato cracks and what to do about it ..

Tomato sunscald: why too much sun can be hazardous to tomatoes...

Blossom Drop: why fruit doesn't set and what to do about it ...

How to identify and treat phosphorus deficiency in tomatoes ....

Are bumps on tomato stems harmful to plants?

How to identify tomato problems and prevent them...

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