Some varieties may have partial resistance, but the reaction of most varieties to the disease is unknown. Infection of foliage can cause leaves and stems to collapse in a watersoaked mass, which becomes light brown when it dries. During morning dews, cobwebby fungal strands may be evident on infected tissues. This fungus is widespread in agricultural soils. Outbreaks occur during warm, humid conditions.
Fungal activity is greatest under a dense canopy.
This fungus does not infect crowns and does not cause stand loss. Alfalfa Diseases Caused By Rhizoctonia Fungi, PPFS-42. White to gray powdery growth on leaf surfaces. Most severe in late summer and early fall. Airborne spores of the fungus are very common in Kentucky.