University of Florida

Sclerotinia Stem Rot

Fungus

Sclerotinia sclerotiorum

Infects

Foliar plant parts and fruit.

Symptoms

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.