Dead circle in St. Augustine grass (grown, spring, shade, buy)

[DaleElson]

I have a dead circle of St. Augustine in my yard. It start out about 3ft in diameter, and has grown over the last 5-6 years to be about 12 feet in diameter. St Augustine runners will enter the circle, but they die off by the winter. Some tufts of winter grassed sprout, but they do not thrive, and die off in the winter. 95% of the circle is dirt. The area is not differently shaded or exposed to the sun or watered, than the rest of the lawn. Any ideas?

Thanks!!!!!
Dale

[gentlearts]

Either a grub or a fungus. You can buy a product to combat either at your garden center. If it is a symmetrical circle, I'd bet on a fungus.
The fungus we had on our centipede grass was a perfect circle.

[wit-nit]

St. Augustine grass is susceptible to brown patch, which is a fungus that will cause brown spots to develop in the lawn, but it rarely kills the grass. It almost always recovers when environmental conditions improve.
Brown patch develops rapidly when air temperatures are between 75 and 85 degrees and wet conditions are present. Spring, fall and sometimes mild winter conditions provide ideal conditions for disease development.
There are several remedies, read more...
SEEDS FOR THOUGHT: St. Augustine grass is susceptible to disease - Midland Reporter-Telegram