Hello,

Based on what I see in your images, this looks a lot like Dollar Spot. Dollar spot is characterized by round, bleached-out or straw-colored spots, ranging from the size of a quarter to the size of a silver dollar. Spots appear as sunken areas in the turf, especially low mown turfgrass (0.5 inches or less). Fluffy white mycelia can be seen when fungus is actively growing during morning periods of heavy dew. Symptoms on individual grass blades appear as bleached-out or tan lesions that are often accompanied by reddish brown bands present at the outer edge of the leaf lesion (except on annual bluegrass).

Dollar spot occurs when daytime temperatures are between 59-88° F (15-31° C) and disease development is favored by warm, humid weather followed by cool nights that produce heavy dews.

Management
Dollar spot (Clarireedia jacksonii) is the most prevalent disease on turfgrass in Michigan. The symptoms of dollar spot are straw-colored spots on leaf blades that form patches in turf about the size of a silver dollar or larger when they start to coalesce. Dollar spot occurs when temperatures are between 60 and 90-degrees Fahrenheit, with high humidity levels. In Joe Vargas’ book, “Management of Turfgrass Diseases,” the cultural management practices he recommends for dollar spot infestations include keeping nitrogen fertilization levels and soil moisture adequate to facilitate turfgrass growth. However, in some cases the cultural management practices will not be enough to suppress or mask the symptoms of dollar spot, and a fungicide program may be necessary.

Dollar spot can be managed with the use of many systemic fungicides like myclobutanil, fenarimol, propiconazole, boscalid, and triadimefon applied every two to three weeks, or with contact fungicides like chlorothalonil applied every 7-10 days. Many products containing combinations of contact and systemic fungicides can also be effective in controlling the disease. MAKE SURE YOU READ AND FOLLOW THE DIRECTIONS ON THE LABEL!

More information at these links.

Dollar Spot - Turf (msu.edu)

Lawn turf update - July 6, 2023 - Turf (msu.edu)

I recommend that you get a confirmed and precise identification of the problem, I recommend you send all your images by e-mail to the MSU Plant & Pest Diagnostics Lab. The experts there can also provide you with the best treatment options. Their email is <personal data hidden> - Please include your name – The lab will let you know if they need a sample sent. FYI – The lab may also ask for additional images too.

Their website is at this link:

Plant & Pest Diagnostics (msu.edu)

Their Contact Information is at this link:

Contact Us - Plant & Pest Diagnostics (msu.edu)

This link will explain the details on submitting a sample to MSU Plant & Pest Diagnostics Lab:

Submit Samples - Plant & Pest Diagnostics (msu.edu)

I hope this helps!