Lawn Problems
Fungus
Fungus most often shows up when the ground is too wet, too often. Over fertilizing will also help bring about this problem. It usually spreads in a circular pattern and can quickly overrun an entire yard if it’s being overwatered. Cornmeal gluten is a natural preventative for fungus, and may slow or halt the spread of a mild case. The best preventative is just paying attention to the amount you’re fertilizing and watering. Even so it can still pop up! I’ve had no luck with the cheap stuff from Home Depot. Commercial fungicide is pricey but, in my oppinion, is the only thing that does a good job dealing with this problem.
Chinch Bugs
Chinch Bugs are a super common here in Austin. They have the most dramatic affect on St. Augustine grass. You can see them if you go stare at your grass in the heat of the day. They run up and down the blades and are about the size of ants. The adults have an oval spot on their back. Usually white or blue around here. The younger ones are a little harder to distinguish. Chinch bugs show up in stressed, dry lawns! My experience is that a yard looks bad BEFORE chinch bugs show up. First thing to check is your sprinkler system to make sure that spot is getting adequate water. They usually show up near the driveway or sidewalk in the heat of summer. I suspect it’s not because they like the hot sidewalk but because that’s where the stressed out grass is.