Hello,
like most of the houses in our neighborhood we are having trouble keeping a healthy looking lawn. About 20% of the grass blades are perpetually yellow or brown. It seems mostly random, but it is worse in some places. The lawn guy came by yesterday and said, yup, you got grubs. I found a few last spring when we planted a tree, and it seemed like raccoons were digging up the lawn then too, so this sounded plausible. Today I dug up a few squares of grass and found exactly zero grubs. I have not noticed any digging since the spring either. So, what is going on? It does not seem related to heat or water. It has been a cool summer. On the shady side of the house it is more moist and the grass grows faster and thicker, but still lots of brown and yellow.