Q. Dear Neil: This is JaMur zoysia planted in my yard in 2006. Itâs almost one-half acre in size and it has done well. I fertilized it two weeks ago with 5-20-15. Most of the yard did well with the feeding, but one section started this discoloring in brown circles. It has progressed very rapidly. What is it, and how can I stop it?.A. A. This is a large patch, also called brown patch. You may recognize it from St. Augustine lawns, but itâs a problem in zoysias as well. It attacks the leaf blades at the bases of their sheaths. They will pull loose very easily. And, as you observed, it starts in circles, and until they grow together, the circles are very noticeable. It can do damage to zoysia, so you would want to apply the fungicide Azoxystrobin to slow its spread. Hopefully the grass will green back up soon. The fungus is more active in cool, wet weather, and we certainly had plenty of both in May. And, by the way, as to your choice of fertilizer ⦠was that based on a soil test from the Texas A&M Soil Testing Laboratory at College Station? Itâs ultimately rare to see them calling for that little nitrogen and that much phosphorus. We are almost always told to avoid phosphorus (middle number) and apply a high-nitrogen (first number) product with much of the nitrogen in slow-release form. You might want to double check your test results.