I received a call from a guy saying his yard was turning brown. So I checked it out and his yard is approximately 3 years old and the front yard was sod and looks great. The back yard was seeded with a "quality" bluegrass blend according to the customer. I did not see any circular patterns or any other distinct patterns. He waters 2-3 times per week for about 45-60 minutes on each station. We have had timely rains and 90 + temperatures.The lack of a pattern make me think subsurface insect, but I did not notice any grubs, etc. Any thoughts?