I am very pleased with my St. Augustine lawn. Despite dire predictions, it has not yet frozen in winter but it has spread handily in moderate shade.
But a problem that was discovered in 1991 by folks in Florida and Texas is called “take all disease”. It can wipe out a St. Augustine lawn.
Now it has hit Georgia in a big way!
Take all disease can also affect bermuda, zoysia and centipede lawns.
Here is a good article from Neil Sperry in Texas.
Take all disease is often confused with brown patch.
Symptoms of take all disease (yellow patches) are seen in fall and spring. Dead spots appear in summer.
Grass leaf blades separate easily from stems with brown patch, blades resist your tug with take all disease.
A homeowner treatment that does not involve fungicides is to put down a 1/2-inch layer of brown Canadian peat moss. Break the peat into small pieces and distribute it evenly over the grass. It is best if you mow the yard first.
Water thoroughly after the peat is spread to settle it to the soil surface. That acidic layer, in contact with the runners, retards development of the fungus and allows the grass to regrow strongly.
You’ll need one 3.8 cu ft bale of peat moss per 1000 sq ft.