Brown Patches in Zoysia lawn

Question

I live in Orlando, FL and have Zoysia in my yard. I had it sodded in March this year. It has developed brown patches in the front yard. To give you a perspective, my house faces south and, therefore, I have sun on the front lawn almost the entire day.

Interestingly, before I mowed, the entire lawn looked green (I couldn’t spot any of the brown patches that you see in the picture). I could only see it after I mowed the lawn yesterday. I normally keep about 2. 5″ – 3″ of mowing height on my lawn with the fear that my lawn might die if I mow it too low.

Another point that I would like to mention, which may not be important, is that while mowing yesterday my lawn mower could not keep up with the torque required to cut the grass and stalled a few times. Can anybody help me understand what could be possibly wrong with the lawn and how to eliminate the brown patches?

To date, I have fertilized my lawn once in May with a starter fertilizer that had Phosphorous (N-P-K) in it.
I have also sprayed Ortho Weed B-Gone once in June on the lawn.

Answer 1

It is likely a fungus, which probably spread through mowing. Most can be treated with fungicides. Here is information on a few common ones:
https://www.gardeningknowhow.com/lawn-care/lgen/grass-fungus.htm

In choosing fungicides you need to select one targeted to the specific problem, as they work differently. That being said, conditions such as brown patch and rust can be treated effectively with Banner, Daconil or Bayleton fungicide.