Stand reductions may be limited to small, scattered thin or dead spots or the entire stand may be killed. Hard, black sclerotia form on the alfalfa root just below the soil surface. In severe cases, they are visible in the dead alfalfa leaf litter on the soil surface. The black sclerotia are off-white to gray colored inside. They are usually 1 to 5 mm in diameter.
Infections can occur on established stands.
Symptoms are like those of young stands. Leaves and stems turn yellow or grayish-green and then collapse. Sometimes affected plants may have a few green shoots remaining even though the other shoots have died back. Sclerotia usually appear in the crown areas or inside the dead stems. If the crowns are severely affected, the plants eventually die.