Yesterday I played my first every round of foot golf on a course in Sapphire. Many of the fairways looked like this. So, what so you think the problem is, or is there a problem?
When I trouble shoot turf problems, the first thing I look at is the pattern of browning or dead turf. This is because if there are straight lines involved, it likely involves human error or vandalism. Grass never dies in straight lines in nature. Roundup being sprayed on grass is an example of where it might die in a straight line.
The second thing I would check for is depth of rooting. By simply tugging on the turf, it shouldn't pull up like a toupee. This time of year, it should be well rooted. If it's not, that signals to me a grub problem, or other root feeding insect.
Finally, observing the leaf blade for mycelium or lesions will be clear giveaways of a fungal pathogen. However, this time of year, fungus isn't a common problem.
In this case, one must look at the stand of grass. It turns out, it isn't a grass at all, rather yellow nutsedge, a weed. Nutsedge behaves like a summer annual in that the first frost will result in dieback. All summer long, this grass looking like sedge, served fine in the rough of this golf course. However, by not controlling it when it was in smaller patches, they now have this to deal with. It outcompeted all the turf in these areas leaving bare ground. We see this weed a lot in our environment because it stays so damp most of the time. On #10 specifically, it thrives as the creek water is constantly depositing seed on the fairway and rough.