Typhula Blight

• Typhula blight spores grow in thatch and at the grass' root zone when temperatures dip to 50 degrees in the fall, according to the University of Massachusetts. During this time, sclerotia begins germinating. Actively growing grass often hides the symptoms. These fungi need moisture and cool temperatures. Snow and temperatures between 34 to 36 degrees allow them to spread over the yard, according to the University of Massachusetts.
  
  

Damage

• Infected turf peeks out as snow melts in the springtime. Gardeners can see the extent of their typhula blight damage, which includes circular patches of discolored gray and black grass. These patches vary in size. They can be a couple inches in diameter or up to 40 inches in diameter. If the damage is moderate, grass can recover from the disease in a few months. Badly damaged areas may need reseeding in the spring. Once the damage is done, there is no reason to apply a fungicide in the spring months, as the fungal spores stop spreading in the heat.
  
  

Fungicides

• Fungicides help prevent typhula blight from infecting your yard. Timing is important part in preventing typhula blight. Apply the fungicide before it snows but not too early, as the fungicide degrades in the sun, according to Don Dale from Turf Magazine. Using a mix of a fungicide containing iprodione with a another containing chlorothalonil provides protection from typhula blight fungal spores and other fungal diseases, according to Dale.
  
  

Cultural Management

• Staying with your mowing routine in the fall reduces the risk of infection. Allowing the grass to grow high creates a hospitable environment for spores. Avoid late-season fertilizing. Excessive nitrogen stresses the lawn, making the grass blades more susceptible for typhula blight damage. Stop fertilizing the lawn after October.