Question
We live in South Carolina and have bermuda grass that is watered by sprinkler systems for 75 minutes once a week at 3 AM.  We have small brown circular spots that we need help identifying and treating.  In the morning when the dew is on the grass the spots look like they are covered with dust.  When you rake them the dust goes airborne and the spot is brown.  We have gotten a lot of rain during the last two weeks.  I have also noticed the same spots on neighbors lawns.  We are cutting the grass at 1-1.5 inches.  Due to high temperatures should keep it cut a little higher? (3rd notch on a Snapper rather than 2nd)
Thank you for taking the time to read and answer my question.  Robbie

Answer
Hi Robbie;
I have no idea how high that setting is. I set mi mower blades to cut 3 inches high, so whatever givs that height.
That sounds like WAY too little water.
How many minutes it is watered, does not matter. The depth of saturation is what you go by.
In temps in the upper 90s to the 100s, you could be losing up to 50% of the water through evaporation.
I water till it is wet to a depth of at least 6 inches.
I water with soaker hoses because they do not spray into the air, so no water is lost through evaporation.
It sounds like you have a fungus.
Whether it is Brown Patch or some other, it IS a fungus.
Apply 10 to 15 pounds horticultural corn meal per 1000, sq.ft, and that will kill the fungus.
Charlotte