Cercospora Leaf Spot (fungus – Cercospora beticola): Cercospora leaf spot causes small, brown lesions with reddish-purple borders. As the spots enlarge, the center becomes gray with purple borders. Severe infection causes the leaves to drop. Crop residue should be plowed under. High humidity and temperatures around 75 to 80 degrees F are optimum for fungal growth. Foliar sprays with a preventative fungicide should be applied when symptoms first appear.
Curly Top (virus): Plants infected with curly top die prematurely. Young leaves roll inward and eventually turn yellow and die. (See section on Curly Top)
Mosaic (virus): Leaves appear puckered and mottled with light and dark green areas. Plants are stunted. Chlorosis occurs on infected leaves.
Powdery Mildew (fungus – Erysiphe polygoni): This is a relatively new disease of both sugar and table beets. Infected leaves are covered by a white, powdery fungal growth. Affected leaves turn red. Sulfur-containing fungicides are recommended.
Root Knot Nematodes: (See Root Knot Nematodes)
Southern Blight: (See Southern Blight)