IF YOU HAVE A ST. AUGUSTINE LAWN YOU MIGHT SEE THIS IN THE SPRING AND FALL

In the fall and spring when temperatures are in the 70s, brown patch fungus becomes active in lawns. St. Augustine lawn is especially vulnerable!
Brown patch usually appears as a yellow and brown circle in the lawn that gradually grows bigger, although it can also be throughout the lawn without any kind of pattern.
If discolored patch is active in your lawn, the first course of action is to reduce the watering frequency since moisture will encourage fungus activity. During cooler temperatures, grass only needs to be irrigated 1 or 2 times a week.
Most of the time, the fungus problem will correct itself, however applying fungicide is also beneficial.
When temperatures get colder than the 70s in the fall and warmer in the spring, the fungus activity ceases.
It’s important to note that the disease only affects the grass blades while the runners and roots stay intact. They will eventually regenerate more grass blades to replace those lost from disease.