How to Manage Pests

Pests in Gardens and Landscapes

Early blight on tomatoes—Alternaria solani

Symptoms of early blight include black or brown spots, usually about 1 cm in diameter, that appear on leaves, stems, and fruit. Leaf spots are leathery and often have a pattern of concentric rings. They usually appear on older leaves first. Fruit spots are sunken and dry and also have a concentric pattern.


Spores of early blight are carried by wind and require moisture for germination and infection. The disease can cause severe damage if conditions remain cool and humid for several days after a rain. Avoid overhead irrigation. Crop rotation is useful in infested gardens. Copper fungicides applied at the first sign of infestation and repeated every 7 to 10 days may provide control.

Fruit spots caused by early blight
Fruit spots caused by early blight

Spots on stems
Spots on stems

Statewide IPM Program, Agriculture and Natural Resources, University of California
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