Early Blight

fungus

Alternaria solani

Common fungal disease of tomatoes and potatoes causing concentric ring lesions.

Identification

Dark brown spots with concentric rings (target pattern) on lower leaves first. Progresses upward. Yellowing around spots.

Defoliation starting from lower leaves. Reduced fruit production. Fruit lesions at stem end. Weakened plants.

Copper fungicide. Bacillus subtilis (Serenade). Remove infected lower leaves. Mulch to prevent soil splash.

Chlorothalonil (Daconil). Mancozeb. Apply at first sign.

Mulch to prevent soil splash. Prune lower branches. Stake or cage tomatoes. Water at base, not overhead. Crop rotation (2 year minimum).

Data confidence: medium | Source: curated_ipm