Typhula blight

Typhula blight is a fungal disease that affects turfgrass, particularly in cold, wet conditions. It is caused by the fungus species Typhula incarnata and Typhula ishikariensis, which are members of the Typhulaceae family. The disease is also commonly known as snow mold, due to its tendency to develop under snow cover.

Symptoms and Identification

The primary symptom of Typhula blight is the appearance of irregularly shaped, straw-colored patches on the turf. These patches can range in size from a few inches to several feet in diameter. The grass blades within the patches may be covered with a cottony, white mycelium that is most visible when the turf is wet.

In addition to the visible symptoms, Typhula blight can be identified by the presence of small, round sclerotia on the infected grass blades. These sclerotia are the survival structures of the fungus, and they can be either red-brown (Typhula incarnata) or black (Typhula ishikariensis).

Disease Cycle

The Typhula blight disease cycle begins when the sclerotia germinate in response to cold, wet conditions. The resulting mycelium infects the turfgrass, causing the visible symptoms of the disease. The fungus continues to grow and produce new sclerotia throughout the winter, under the protection of the snow cover.

When the snow melts in the spring, the sclerotia remain on the turf and in the soil, where they can survive until the next winter. The disease can therefore recur year after year, unless effective control measures are implemented.

Management and Control

Management of Typhula blight involves a combination of cultural practices and fungicide applications. Cultural practices include maintaining a balanced soil pH, avoiding excessive nitrogen fertilization, and removing snow from the turf as quickly as possible.

Fungicides can be used to control Typhula blight, but they must be applied before the snow cover forms. The most effective fungicides for this purpose are those that contain the active ingredients iprodione, propiconazole, or thiophanate-methyl.

See Also

• List of turfgrass diseases
• Snow mold
• Fungicide