Snow mold

The causative agent of the disease is the fungus Sclerotinia nivalis (synonym Microdochium nivale), which causes a serious infectious condition known as snow mold. This pathogen acts as a facultative parasite that survives in the soil and on crop residues as mycelium or conidia, ready to infect plants when the appropriate environment is present.

The main crops susceptible to infection include winter cereals such as wheat, rye, barley, and triticale. Furthermore, the disease poses a significant threat to perennial forage grasses used in pastures and turf management, especially in regions with severe winters and prolonged snow cover melting periods.

Symptoms become visible immediately after the snow melts. Plants are covered with a dense white or pinkish fungal mycelium. The affected tissues lose their chlorophyll, turning gray or brown, and eventually rot, which often leads to the death of the tillering node and complete plant collapse.

The development of the pathogen is favored by low temperatures, with an optimal range between 0 and 10 degrees Celsius. Key factors contributing to the spread of the disease are high humidity levels, thick snow cover on unfrozen soil, and a long, cool spring that sustains the activity of the fungus on weakened crops.

The harmfulness of the disease is reflected in the thinning of plant stands and the resulting loss of yield, often requiring total reseeding. To protect crops, it is essential to employ an integrated approach: seed treatment with fungicides, crop rotation, avoiding excessive nitrogen fertilization before winter, and selecting resistant crop varieties.