Crown Rot

• The base of the plant — the crown — turns brown, water-soaked, and soft, at or just below the soil surface
• Plant collapses or falls over at the soil line as crown tissue loses structural integrity
• White or gray mycelium visible at the crown when conditions are moist, in some cases accompanied by hard black structures (sclerotia in Sclerotinia infections)
• Roots below the affected crown may be healthy initially — the problem starts at the crown, not at root tips
• Leaves wilting and yellowing as the crown fails to transport water upward, despite adequate soil moisture
• Rotten odor from the base of the plant in advanced cases with secondary bacterial colonization

Crown rot is a clinical description more than a single disease — several pathogens can produce this pattern by attacking the plant at the soil-air interface where moisture accumulates. Phytophthora and Pythium are water molds that need free water to produce and spread spores; they are most destructive in wet, poorly drained soil. Sclerotinia sclerotiorum (white mold) produces cottony mycelium and hard black sclerotia and is favored by cool, wet conditions. Fusarium crown rots develop in warmer conditions and often affect strawberries and peppers. In all cases, wet soil at the crown combined with susceptible plant tissue creates the opening.

1. 01Correct drainage before planting susceptible crops: raised beds, mounded rows, or amended soil all reduce the wet-crown conditions that pathogens require
2. 02Plant at the correct depth — burying the crown of strawberries, basil, or tomatoes too deep concentrates moisture around the most susceptible tissue
3. 03Water at the base and avoid wetting the crown directly; drip irrigation or soaker hoses are preferable to overhead watering for susceptible perennials
4. 04Remove infected plants promptly, taking the surrounding soil, and do not replant with the same crop family in that spot
5. 05Allow soil to dry between waterings — the single most effective cultural step for reducing Phytophthora and Pythium activity
6. 06For strawberries: plant certified disease-free stock and replace beds every 3–4 years rather than renovating beds with known crown rot history

If crown rot is killing plants repeatedly in a bed where drainage seems adequate, a diagnostic lab can identify which pathogen is responsible — the distinction between Phytophthora, Sclerotinia, and Fusarium affects which fungicide, if any, is appropriate.

• Crown Rot of Vegetables and Strawberries— Penn State Extension
• Root and Crown Rots of Strawberry— UC ANR Integrated Pest Management