Grow only varieties with at least moderate resistance to Fusarium wilt. Use varieties with higher resistance levels in fields where the disease has been diagnosed. Annual Kentucky Alfalfa Variety Test Report, Progress Report 351. Circular or irregularly shaped spots on leaves. Spots may be tan, brown, or black, and may have yellow halos.
Leaves fall off when infections are severe.
These fungi survive in undecomposed leaf tissue on the soil surface. Spores are spread by air currents or rainsplash. Infections occur when leaves are wet with dew or rain. Serious outbreaks can occur during extended periods of humid, wet weather. Rotate away from forage legumes for at least two years.