The causal fungus is soil borne. The disease is worse in moist conditions. No chemical controls are listed. The early symptoms of black leg are dark sunken cankers at the stem base or light brown circular spots on the leaves. Plants wilt when the canker girdles the stem.
Black specks form in the cankers and spots.
The disease is easily spread and overwinters in diseased crop residues. No chemical controls are listed. Alternaria Leaf Spot Spots with dark concentric circles form on the lower leaves. A dusty fungal growth occurs on the spots in moist weather. When the crop is stored, the spots enlarge.