I have been having a problem with grass turning brown in my z-52 zoysia grass. I thought it was a fungus but I have sprayed it with Immunox fungicide a couple of times over the last 3 weeks. Could this be an insect problem? Could the immunox be making the grass worse? I sprayed only in the morning before temperatures exceeded 75 degrees. The pictures below were taken this morning---a week and a half after the last time I sprayed.

It was planted as sod 2 years ago and was solid, beautiful bright green until a month ago.

The strange thing is that so many of the pieces seem to have shallow roots and have a couple of green leaves but the rest and the sheaths are brown then there are some that are totally dead.

I always really appreciate the expertise you guys share here!