Phoma Leaf Spots and Root Rot

HOSTS

• Beets
• Chard

DESCRIPTION

Phoma leaf spot and root rot is caused by the fungus Phoma betae.

BIOLOGY

P. betae is often introduced to fields through infected seeds and will overwinter on plant debris in the soil for extended periods. Further spread of the pathogen occurs when the spores, found in the rings of the foliar spots, are moved by wind, water, equipment, or people to new hosts.   

Plants that are infected as seedlings will exhibit symptoms of damping-off. Plants that are more mature at the time of infection will display foliar lesions.  

SYMPTOMS

• Seedling death
• Round, light brown spots with dark concentric circles on leaves. 
• Dark, necrotic lesions on plant roots. 

GENERAL MANAGEMENT

• Use certified disease-free seed.
• Employ crop rotation. Allow 3 years to pass before an area is planted with Beta genus crops again.