Sclerotinia Crown and Stem Rot
Sclerotinia sclerotiorum, Sclerotinia minor
Fungus
Stems
Roots
Leaves
Overview
A soil-borne fungal disease causing crown rot, stem rot, and wilt in many crops. Produces white cottony mycelium and hard black sclerotia. Related to White Mold but primarily attacks the crown and lower stem.
Symptoms
Water-soaked lesions at the crown and lower stem. White, cottony mycelium on affected tissue. Hard, black sclerotia inside and on stems. Wilting and collapse. Lettuce drop (entire head collapses).
Environmental Conditions
Cool
Prevention
Rotate with non-host crops. Improve air circulation. Avoid dense planting. Reduce irrigation frequency. Apply Coniothyrium minitans to soil.
Management
Remove infected plants. Apply biological controls (Coniothyrium minitans). Improve drainage. Avoid overhead irrigation. Deep tillage to bury sclerotia.