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Snow mould

Appearance: Pink or whitish-gray fuzzy or cottony mat of mould will appear on the surface of your lawn during the spring melt. In some instances, there will be dead patches in your lawn where the mat appears. The mould rarely kills the grass outright; however, it may take most of the summer for your grass to recover.

Cause: The mould spores are always in your lawn; however, snow mold flourishes when there is a prolonged snow melt in the spring.

Growing Season: Spring, as the snow melts.

IPM Toolkit:

  • Preventive tools:

    • Do not fertilize later than August 15. Fertilized lawns are very soft and succulent; perfect conditions for snow mould to grow in the spring.
    • Remove leaves and other organic debris from your lawn in the fall, which encourages mould to grow.
    • Follow healthy lawn practices to mow grass at the proper height and reduce thatch.
  • Physical tools:

    • Encourage snow to melt quickly by spreading out large snow piles or area of snow compaction.
  • Biological tools:

    • Not Applicable
  • Least toxic chemical tools:

    • There are no least toxic chemical tools available to control snow mould.