White Mold

HOSTS

• Brassicas
• Beans
• Brussel sprouts
• Leafy greens
• Potato
• Root crops
• Solanaceous crops
• Ornamental plants
• Weeds

DESCRIPTION

White mold is a fungal disease caused by Sclerotinia sclerotiorum. The pathogen has a wide host range that includes fruit and vegetable crops and ornamentals. Depending on the affected host, the disease can be called different names such as cottony soft rot in carrots, drop in lettuce, and head rot in cabbage.

BIOLOGY

S. sclerotiorum produces hard, black structures called sclerotia during late summer and early fall. The sclerotia can survive dormant in the soil for extended periods. When conditions are wet and cool, optimally 60 °F to 70 °F, the sclerotia will produce fruiting bodies which release spores. The spores are spread by wind and water to new hosts.

SYMPTOMS

• White fungal growth that often starts around the soil line. 
• Hard, dark structures that develop on and within infected plant tissue. 
• Wilted stems and foliage 

GENERAL MANAGEMENT

• Remove and dispose of infected plants. 
• Manage weeds as they can serve as alternative hosts for the disease.
• Minimize moisture on plants by utilizing drip irrigation and providing space between crops for ventilation.
• Rotate with nonsusceptible crops such as grains or corn to reduce disease build-up.