White Mold (Sclerotinia): Identification, Control & Prevention

White mold (Sclerotinia) affects 360+ plants, including beans, peas, lettuce, and brassicas. On tomatoes it's called timber rot. Symptoms: water-soaked spots on blossoms, stems, leaves, pods; wilting, yellowing, death; pod rot. Most susceptible during flowering; seedlings also vulnerable. Spores release in cool weather, wind-borne. Early destruction of infected plants is critical.

Identification

• Water-soaked stem lesions; plant may look healthy above.
• Individual stem wilting with tan base discoloration.
• Tan to dark brown stem lesions; dense cottony growth in high humidity.

Control

• Destroy diseased plants immediately.
• Remove infected soil; replace with clean soil.
• Use plastic/mulch barrier over infected ground.

Prevention

• Well-drained soil; proper spacing; avoid poor air circulation.
• Water early day; avoid wetting tops.
• Spray approved fungicide pre-bloom and again a week later.
• Control weeds—alternate hosts.
• Remove all crop residue post-harvest; spores survive winter.