St Ausustine Grass – Brown Patch Disease
Q: What is wrong with our St Augustine grass? Noticed it on this hill after several days of rain this week with a fairly sudden onset.
A: It looks very much like brown patch disease, Rhizoctonia solani, to me. The orange rim is pretty characteristic.
Excess water is usually the cause.
The chemical propiconazole (click for sources) works pretty well to stop it.