Early Blight
Dark brown to black spots develop on older leaves, often with distinctive concentric rings that create a target-like pattern. Affected leaves gradually turn yellow, dry out, and fall off. Stems may develop dark lesions, and fruits can develop dark, sunken spots near the stem end, reducing both yield and fruit quality.
Dark brown to black spots develop on older leaves, often with distinctive concentric rings that create a target-like pattern. Affected leaves gradually turn yellow, dry out, and fall off. Stems may develop dark lesions, and fruits can develop dark, sunken spots near the stem end, reducing both yield and fruit quality.
Early blight is caused by the fungus Alternaria solani. The disease spreads through infected plant debris, contaminated soil, wind, rain splash, and overhead watering. Warm temperatures, high humidity, and prolonged leaf wetness greatly increase the risk of infection.
Remove and destroy infected leaves and plant debris immediately. Avoid overhead watering and water at the base of the plant early in the day. Improve air circulation through proper spacing and pruning. Apply a suitable fungicide according to the product label if the disease continues to spread. Rotate crops and avoid planting tomatoes or potatoes in the same location each year.
Plant disease-resistant varieties whenever possible. Space plants properly to improve airflow, mulch around plants to reduce soil splash, remove infected plant debris at the end of the season, and practice crop rotation for at least 2–3 years. Keep foliage as dry as possible by watering at the base of the plant.