Managing Snow Mold Diseases of Winter Cereals and Turf

Most snow mold pathogens cause plant injury only under prolonged snow cover, so snow mold diseases are severe primarily in regions where snow cover persists for more than 100 days. Even within these regions, disease occurrence and severity varies greatly from year to year. When disease is severe, individual fungal colonies coalesce, resulting in substantial losses in plant stand (20). In other years, pathogen growth is limited and losses are insignificant. Infection foci develop with a pattern and species composition determined by snow cover, microhabitat (28) and inoculum load. Several approaches to the control of snow mold diseases have been investigated, including the use of resistant cultivars, snow removal, modified management practices, fungicides, and biological control. To date, the greatest success has been achieved with fungicides and resistant cultivars, but recent progress in biological control indicates strong promise in this area as well. Since most control measures must be initiated before snowfall (before disease severity is known), their cost-effectiveness is particularly important.