Gray leaf mold.........on cool season grass.
Check this site out for possible hosts and identification. There is more accurate sites with photos, so do some home work on cool season turf grasses.
Propiconazole, chlorthalonil, pacloburtazole, is some of the treatment chemicals.
Most of these isn't too cheap, so if you are doing your own lawn, you can go to the local big ticket stores and purchase OTC products to do small areas.