Septoria Leaf Spot

fungus

Septoria lycopersici

Very common tomato disease causing small spots with dark borders and light centers.

Identification

Numerous small (1/8 inch) circular spots with dark brown borders and gray-tan centers. Tiny black dots (pycnidia) visible in centers with magnification.

Damage & Symptoms

Starts on lower leaves, progresses upward. Severe defoliation. Reduced fruit size and sunscald on exposed fruit.

Organic Control

Copper spray. Bacillus subtilis. Remove lower leaves. Mulch to prevent splash.

Chemical Control

Chlorothalonil. Mancozeb. Apply preventively.

Prevention

Mulch tomatoes. Prune lower leaves. Stake or cage. Water at base. Crop rotation (2 years). Disease-free transplants.

Data confidence: medium | Source: curated_ipm