Disease

Septoria leaf spot

Septoria lycopersici and related species

A fungus that spots tomato leaves from the bottom up. It does not usually infect fruit, but can strip a plant of leaves.

Signs

Warm, wet weather and splashing water. The fungus survives on debris and on nightshade weeds.

Tomato, pepper & eggplant; Lettuce, spinach & herbs.

Treatment by crop

Cultural, biological and chemical options in the order to use them, and notes written for each crop.

Identification is free. Treatment is on the Home and Pro plans.

Open in the key See plans

Look the plant over, leaf undersides included. Are insects, mites, slugs, eggs, webbing or droppings on it?
No, only damage or discoloration
Where is the problem?
Leaves
What does the leaf damage look like?
Distinct spots or lesions
Where on the plant are the spots?
Older, lower leaves first, moving up
What do the spots look like?
Many small round spots with pale centers

Not a match? Start the key or describe what you see.

More from university Extension: search Extension pages on septoria leaf spot, or find a plant diagnostic lab through your state's Extension.