Snow mold
Typhula blight
Causal Agent:
- Typhula spp. fungi are responsible for causing Typhula blight, also known as gray snow mold or speckled snow mold.
Hosts:
- Typhula blight affects various cool-season grasses, including turfgrasses and winter wheat.
Symptoms:
- Circular Patches: Circular to irregular patches of damaged or dead grass appear in affected areas.
- White to Gray Mold: Infected grass may be covered with a white to gray mycelial mat during wet and cool conditions.
- Pink "Fringe": In some cases, a pinkish "fringe" may appear at the outer edges of the patches.
- Distinct Borders: Patches often have distinct borders between healthy and infected areas.
Disease Development:
- Favorable Conditions: Typhula blight thrives in cold, wet, and humid conditions, typically during late fall, winter, and early spring when snow cover is present.
- Snow Cover: The presence of snow provides insulation, creating a microenvironment conducive to disease development.
- Fungal Growth: The fungus grows within the snowpack, infecting the grass beneath.
Identification:
- Distinct Patches: Identify circular or irregular patches with damaged or dead grass.
- Mycelial Mat: In wet conditions, look for a white to gray mycelial mat covering the infected grass.
Management:
Cultural Practices:
- Avoid Nitrogen Fertilization: Reduce late-season nitrogen fertilization to minimize lush grass growth, making the turf less susceptible.
- Improve Air Circulation: Prune trees and shrubs to improve air circulation and sunlight penetration.
- Snow Removal: Promptly remove snow from affected areas to expose the turf to air and sunlight.
Chemical Control:
- Fungicide Application: Application of fungicides, especially in the fall before snow cover, can help prevent or reduce Typhula blight.
Resistant Varieties:
- Choose Resistant Varieties: Select turfgrass varieties that are resistant or less susceptible to Typhula blight.
Post-Disease Practices:
- Overseed: Reseed affected areas in the spring or fall with disease-resistant grass varieties.
Regular Monitoring:
- Scouting: Regularly monitor turfgrass areas for signs of Typhula blight, especially during periods of snow cover and favorable conditions.
