If you’re seeing small, round patches of discolored grass in your otherwise healthy lawn, you may have dollar spot fungus.  Unfortunately, these spots don’t have any monetary value.  (Do you get the play on words?  Ha!)  Dollar spot can be found in both cool season and warm season turfs, so no lawn is safe. Know that ignoring the problem won’t make it go away but Turf Masters can! 

Dollar Spot Identification

The fungus that causes dollar spot is called Clarireedia jacksonii (formerly Sclerotinia homoeocarpa). When this fungus takes over, you will see small, circular, straw‑colored, sunken patches that are about two to six inches in diameter. The circular patches are typically the size of a silver dollar, which is where the disease gets its name. However, in severe cases, spots can grow very large and be irregularly shaped . These damaged areas or brown patch areas are best seen in the early morning when dew is present on grass blades and the pathogen is active.  You may even see a white, cottony, growth called mycelium in the affected patches. 

Dollar spot can be present when the temperature ranges from 50°F to nearly 90°F, but flourishes when the temperatures are between 60°F and 70°F. These warm temperatures combined with prolonged periods of wetness can encourage growth of the fungus. 

The disease can spread in a variety of ways.

  • Lawn mowers
  • Other lawn equipment
  • Infected grass clippings
  • Shoes (walking in the grass)
  • Wind
  • Water

Fun fact: Landscapers, golf course superintendents, and other turfgrass professionals spend more money on chemicals to control this fungus than any other disease. 

Preventing Dollar Spot

Fortunately, dollar spot is fairly sporadic but can have a variety of causes.  Because of this, preventative treatments are not effective; however, general lawn care practices can help reduce the likelihood of this disease.  Here are some tips:

  • Water deeply and infrequently versus shallow and frequently.  Dry or drought conditions encourage dollar spot. Most turfgrasses need at least one inch of water once per week and more during extremely hot or dry spells.
  • Fertilize your lawn at the appropriate times and use a professional.  Incorrect amounts of nitrogen can cause dollar spot.
  • Mow your lawn at regular intervals with a sharp blade.  Mowing below recommended heights can dry and scorch grass and soil. Grass blades shield the soil from wind and sun, helping regulate temperature and moisture levels. 
  • Reduce thatch build-up by collecting grass clippings. Removing thatch deeper than one inch also helps eliminate excess moisture and reduce turfgrass stress, while removing sources of bacteria that may lead to dollar spot.
  • Core aerate your lawn annually in the spring or summer.

Fungal diseases in your lawn can not only be embarrassing but are often difficult to eradicate without the appropriate products and proper care.

If you have any questions on how you can best care for your lawn and prevent fungal diseases such as dollar spot, let us know.  If you have a severe case of dollar spot, fungicides can sometimes help.  We’re here to help. Contact Turf Masters today.


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Categories: Lawn Diseases