Most of the “why is my lawn dying” calls we get in the Austin area come down to a small handful of repeat offenders. Central Texas heat, humidity swings, and alkaline soil create pretty specific conditions for pests and disease — and once you know what you’re looking at, most of these are manageable. Here’s how to tell them apart.
Chinch Bugs — The #1 St. Augustine Pest in Austin
What it looks like: Yellow patches that expand outward, almost always starting in the hottest, sunniest part of the yard — often near a driveway, sidewalk, or south-facing wall that radiates heat. The grass looks drought-stressed, but here’s the tell: watering it more doesn’t fix it.
Why it happens: Chinch bugs are small (BB-sized), black insects with irregular white markings on their backs, and they thrive in hot, dry conditions. They feed on grass at the base of the blade and inject a toxin that causes the yellowing — it’s not actually a water problem, even though it looks like one.
How to confirm it: Get down on your hands and knees at the edge of a yellow patch and look closely at the soil line, or try the float test — cut both ends off a coffee can, push it a couple inches into the soil at the edge of a damaged area, fill it with water, and watch for chinch bugs floating to the surface within a few minutes.
What to do: Treat with an insecticide labeled for chinch bugs (bifenthrin and permethrin are both common active ingredients). Reapply every few weeks during peak season (June through September) until it’s resolved, since chinch bugs can have multiple generations in a single Austin summer.
Brown Patch — The Most Common Fungal Disease Here
What it looks like: Roughly circular brown or tan patches, sometimes with a slightly darker “smoke ring” edge. If you tug on a blade at the edge of the patch, it often pulls loose easily right at the base — that’s one of the more reliable ways to distinguish brown patch from other causes of yellowing.
Why it happens: Brown patch shows up in fall and spring when nights cool into the 50–75°F range with high humidity — conditions Central Texas gets reliably twice a year. Evening watering is the single biggest contributing factor, since it leaves grass blades wet overnight, which is exactly what the fungus wants.
What to do: Shift all watering to early morning if you haven’t already — this alone prevents a lot of brown patch. For active outbreaks, a fungicide labeled for brown patch (azoxystrobin and myclobutanil are common) will help. For prevention, apply MicroLife Brown Patch 5-1-3 in September before the fall disease window opens — it’s formulated specifically for this and also works as a complete fertilizer.
Gray Leaf Spot — Mid-Summer, Mostly St. Augustine
What it looks like: Small, diamond-shaped gray-brown lesions on the grass blades themselves, rather than the circular patch pattern of brown patch.
Why it happens: Hot, humid mid-summer conditions combined with excess nitrogen. It often shows up shortly after a heavy summer fertilizer application, which is one more reason to stick to the recommended fertilizing schedule rather than over-applying.
What to do: Cut back on nitrogen during peak summer heat and avoid evening watering, same as brown patch. A fungicide containing propiconazole can help an active outbreak.
Take-All Root Rot — Slower, and Easy to Misdiagnose
What it looks like: Gradual yellowing that spreads into thinning and dead patches over weeks, sometimes mistaken for a watering or nutrient problem because it develops slowly. The giveaway is underground: pull up a piece of affected sod and check the roots — they’ll be short, black, and rotten rather than white and healthy.
Why it happens: It’s a soil-borne fungus, and it’s notoriously stubborn once established. Stress on the lawn — drought, compacted soil, poor drainage — makes it worse.
What to do: There’s no quick fix. Focus on reducing stress on the lawn: improve drainage, avoid overwatering, and consider topdressing with peat moss along with a preventive MicroLife Brown Patch 5-1-3 application, which also has some effect on take-all. This one takes patience more than any single product.
Armyworms — The Fast-Moving Bermuda Threat
What it looks like: Bermuda lawns that go from fine to visibly stripped in a couple of days, typically August through October.
Why it happens: Fall armyworms move in waves and can strip a Bermuda lawn bare in 48–72 hours once they arrive in numbers — they’re one of the few lawn problems in Austin that genuinely requires fast action rather than a wait-and-see approach.
What to do: If you notice thinning grass and chewed blades in late summer or early fall, treat immediately with an insecticide labeled for armyworms rather than waiting to see if it gets worse.
When in Doubt, Do the Tug Test
A lot of these problems get confused with each other, and with simple underwatering or winter dormancy. If you’re not sure what you’re looking at: gently tug on a patch of grass. If it resists and roots hold, the lawn is alive and likely dealing with a treatable issue. If it pulls up with no resistance and no roots, that’s a stronger sign of a deeper problem — worth a call before you guess at a treatment.
For more detail on any of these, including grass-specific mowing and watering schedules, see our full Lawn Care Guide. If you’re dealing with a lawn problem right now and want a second opinion before you spend money on the wrong treatment, call us at (936) 510-0964 — we talk through this exact thing with Austin homeowners every day. And if the damage is bad enough that patches need to be replaced outright, get a quote for fresh sod.