These dead shoots are often easily seen scattered through the field in summer and fall. This disease can move into the crown of the plant causing a bluish-black discoloration which results in damage to the whole plant. Infected plants are usually scattered throughout a stand and are detected by their yellow-green color and stunted growth. Mild symptoms consist of leaf mottling with a slight cupping or upward curling of the leaflets and some reduction in plant height. Severely infected plants are stunted and yellow-green, with many spindly stems and small, distorted leaflets.
Diseased plants are usually most evident in the regrowth after clipping.
Cross sections of taproots show a yellowish brown discoloration in contrast to the white color of healthy taproots. Wilting shoots are the first evidence of the disease. In early stages, the leaves may wilt during the day and regain turgidity at night. Bleaching of the leaves and stems follows, and a reddish tinge often develops in the leaves. Only one side of a plant may be affected at first, and after several months, the entire plant dies.