Can someone please tell me what is going on with this yard in Oklahoma. It is Tiff grass was sprayed in October with simazine and in March with pendulum and fertilized in early May. I dug up 1 foot deep in dead areas to see if it was grubs and none were present. I did notice some really small tree roots beneath the surface from a near by neighbors tree. This has been coming on since last summer and getting worse. The areas almost look rotted. I would like to know what this , and whats causing it and how to fix the problem or I'm gonna end up losing the whole yard.. Anyone who can comment on this and give me their opinion Id really appreciate. Thanks.