Common in summer
Chinch Bug Damage: How to Spot and Confirm It
Chinch bugs are tiny insects that suck the juices from grass in hot, dry, sunny spots — common in St. Augustine and other warm-season lawns. Their damage looks like drought that keeps spreading even though you're watering, which is the tell that sends you looking for the bugs themselves.
How to tell
- Yellow-then-brown patches in the hottest, sunniest, driest part of the lawn.
- Damage that keeps expanding despite regular watering — unlike plain drought, which responds to water.
- Tiny black-and-white insects (and smaller red nymphs) when you part the grass at a patch edge.
- Worst along sidewalks, driveways, and south-facing edges where it's hottest.
What to do
- Step 1
Part the grass and look
At the edge of a spreading patch — where damaged meets healthy — part the grass to the soil and watch for the fast-moving black-and-white adults and reddish nymphs. Confirming them is what separates chinch bugs from simple heat stress.
- Step 2
Use water to tell them apart
Plain drought greens back up after a deep soak; chinch-bug damage keeps spreading anyway. If watering isn't stopping it and you find the insects, it's chinch bugs.
- Step 3
Treat only what's confirmed, with a labeled product
If you confirm chinch bugs, choose an insecticide labeled both for chinch bugs and for your grass — some products injure St. Augustine — and treat the affected area. Reseed or plug killed spots once they're gone.
Always read and follow the product label — it is the legal authority on rates, timing, and safety. These windows are regional estimates, not a prescription; defer to the label and your local extension office.
Preventing it next season
Mow high, water deeply, and avoid excess nitrogen and thatch, which chinch bugs favor. A healthy, properly watered lawn is far more resistant, and catching them early keeps the damage small.
Frequently asked questions
- How can I tell chinch bugs from drought?
- Both look like browning in hot, dry spots, but drought recovers after a deep watering and chinch-bug damage keeps spreading despite water. Part the grass at a patch edge — if you see tiny black-and-white insects, it's chinch bugs.
- What grass do chinch bugs attack most?
- St. Augustine is especially prone to chinch bugs, though they affect other warm-season and some cool-season lawns too. Always confirm the insects before treating, and use a product labeled for your grass type.