How to Manage Pests

Pests in Gardens and Landscapes

Early blight—Alternaria solani

Early blight is primarily a disease of stressed or senescing plants. Symptoms appear first on the oldest foliage. Affected leaves develop circular to angular dark brown lesions 3 to 4 mm in diameter. Concentric rings often form in lesions to produce a characteristic target-board effect. Severely infected leaves turn yellow and drop. Dark brown lesions develop on stems in later stages of the disease. Infected tubers show a brown, corky dry rot.

Life cycle


Early blight can be minimized by maintaining optimum growing conditions, including proper fertilization, irrigation, and management of other pests. Grow later maturing, longer season varieties.

Early blight lesions on leaf
Early blight lesions on leaf
Lesions on stemLesions on stem

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