I live in Fenton MO (suburb of St Louis MO)
I have a Zoysia lawn.
I fertilize in mid-spring with Scotts with Halts. I generally do not fertilize again. To deal with what I believe to be a fungus attack, I have applied a fungicide for lawns but I don't have the container and don't remember the manufacturer.
I irrigate only in July and August, only as needed. Irrigation is not automatic.
It is an established lawn, I believe over 15 years.
I mow at a level of about 4".
I have not had a soil test.
My question is based on problems that I had 3 seasons ago and now is attacking another part of the lawn. Here is overall view of the lawn:
This is a close photo of an unaffected section of that lawn:
Here is a photo of the affected area:
Here is a photo of a wider view of the affected area:
Three seasons ago I had the same thing in another area. I applied a fungicide with a bit of water soluble fertilizer. I plugged the lawn with zoysia plugs the next season and they are filling in. I added more plugs again this season and they are doing fine. Here is a photo of the area:
Not completely better, but better than it was. What you are seeing is zoysia and some weeds, primarily Oxalis and crab grass. Generally, zoysia will crowd out weeds and did for many years.
My question is, is this a fungus and is there anything I can do to stop the spread (seems that the fungicide and light fertilizer helped three seasons ago. I'd like to be more proactive, I guess. I don't want to apply chemicals needlessly, but I want to help the lawn.
I do not have a preference between synthetic or organic solutions. However, I would love to find something that works, if possible.
Thank you for any help!