University of Florida

Sclerotinia Stem Rot


Sclerotinia sclerotiorum


Foliar plant parts and fruit.


Lower stem canker at or above soil line, enlarging to girdle stem causing plant wilt and death; stems hollow and fill with gray-white fungus and hard, black sclerotia (1/16 - 1/2 in); fruit develop a watery decay and exhibit mycelium and sclerotia.

Pathogen Spread

Soilborne, machinery or water-carried infested soil, rain, or wind disseminated spores from germinated sclerotia at the soil line.

Favorable Conditions

Cool, moist weather (66-72 F.) for sclerotial germination and initial plant infection. Much more common in area 1 (Appendix 9) than elsewhere. A mid-winter problem, traditionally.

Sclerotinia Stem Rot Pictures

sclerotinia stem rot
Image # 108.
Sclerotinia stem rot
characteristic white mycelium on infected plant parts producing a hollowing of pith tissue.

Sclerotinia stem rot
Image # 109.
Sclerotinia stem rot-
diagnostic sclerotia; hard black in various sizes from 1/16 - 1/2 in. long that form in infected stem tissue.

Sclerotinia fruit rot
Image # 109.
Sclerotinia fruit rot-
white mycelium emerging from stem end of tomato fruit.