..........where you live, I'm betting you have Bahia grass and that's the culprit. Bahia grows 2 to 4 inches a day, goes to seed, and has a stalk like a weed-whacker line. Check the bay areas of the wing/stab where the holes/slits are. Bet you find the top of the grass stalk or seeds. I'm having this problem in my area, especially after all the rain we've had lately.
It's so bad, I've posted (Clubhouse) a question about how to eradicate this. I have a couple of good leads, but this stuff is hard to kill. For now - just cut, and cut often.