A: The likeliest problem right now is chinch bug damage. We’re talking with a lot of people who are seeing this problem right now… in fact it’s the single most common turf issue we’ve been seeing lately.
Chinch bugs feed on St. Augustine during the summer months, and can do a lot of damage. They’ll start in the hottest, driest parts of your yard – near your air conditioner, near the curb, sidewalk, alley, or any similar area which is hot, dry, and especially where the soil compaction is the worst. They’ll suck sap from the turf, and their feeding also injects a harmful enzyme into the turfgrass that continues the damage. The grass will remain well rooted (as opposed to grub damage later, when the turf won’t be all that well rooted down), but entire runners can die. This problem is worse in lawns which are not mowed often enough; long pieces of cut grass encourage a thick thatch, which then encourages the chinch bugs.
This problem is best treated with Bonide Insect & Grub Killer, although any turf insecticide labeled for chinch bugs can get the job done if properly applied. Fertilize the St. Augustine well this September to encourage regrowth. Mow often, and if your soil is heavily compacted or your thatch is thick, aerate the lawn.
One last piece of chinch bug information worth mentioning; many species of ants and predatory insects feed on chinch bugs, so if you’re in the habit of applying insecticide to the lawn on a regular basis to wipe out all the ants, you may well be working against your own best interests. Treat for insects when you have a genuine problem, but try not to get into a habit of constant insecticide applications. If you do, the moment you halt your treatments for any reason, problems like this tend to explode for a while.