Question: My St. Augustine has dead brown areas. The blades pull loose easily from the runners. What is it, and what can I do to stop it?
Answer: That's brown patch, a common and comparatively harmless fall disease. It attacks the leaf blades where they attach to the runners. That's why they pull loose so easily. You will see it in late September and through October. It is spread by moisture, so don't water at night during the fall. Turf fungicides will generally stop it in its tracks, but treat at the first signs of an outbreak. You'll see leaves starting to turn yellow in fairly distinct round patches. That's the time to treat.