9 Common Tomato Diseases: Identification and Prevention

Tomato problems are usually insects, diseases, or environmental stress. Choose disease-resistant varieties (anthracnose, wilts, blight) for better success. Here's a quick diagnostic guide.

Anthracnose

Fungal. Indented yellow/brown circular spots on stems, leaves, fruit. Mulch, remove infected parts, avoid overhead watering, rotate crops yearly.

Blossom Drop

Caused by temps above 85°F or below 58°F. Plants abort flowers. Use row covers to raise night temps. Little can be done for daytime heat. Keep plants healthy to rebud after heat wave.

Blossom-End Rot

Calcium deficiency from uneven watering. Sunken dead area at fruit bottom. Water consistently, mulch 2 inches to conserve moisture.

Damping Off

Fungal. Seedlings collapse or fail to germinate. Plant at optimal soil temp, presoak seeds, use sterile mix/containers, let soil dry between waterings.

Early Blight

Fungal. Brown/black spots with dark edges on lower leaves, merging into blotches with concentric rings. Warm, wet weather spreads it. Plant resistant varieties, rotate yearly (avoid former pepper/potato spots), harvest ripe fruit promptly.

Late Blight

Water-soaked leaf areas rapidly becoming greenish-black blotches with white downy growth underneath. Fruit rots into foul masses. High humidity/dew favors it. Avoid overhead watering, mulch, rotate yearly (avoid former potato/pepper soil).

Mosaic Virus

Viral. Yellow/green mottled, distorted, cupped leaves. Remove and destroy infected plants. Buy resistant varieties.

Sunscald

Sunburn on fruit: soft, pale, dry patches. Maintain foliage cover or use shade cloth.

Verticillium Wilt

Fungal. Sudden wilting, often overnight. Lower leaves die first. Plant resistant varieties, rotate crops yearly.

Grow Great Tomatoes

With good practices, tomatoes thrive. Tips: start strong, try fun growing methods, maintain plant health.