About a month ago I had roll on Kikuya lawn planted. Since then the area has had a lot of rain and irrigation and everything seemed to be going okay until recently when portions started thinning out. Below are pictures of what I mean.
Here you can see the part that is thinning out vs. a healthier part. It seems to be spreading and started out as a much smaller area.
Here is a close up of the grass at the troublesome area.
I have no idea what is doing this. I haven't been able to spot any pests or ants and have been very careful when mowing the lawn.
Is there any way to determine the cause?