Buffalo Outdoor • May 2026 • Fort Worth, TX
Chinch Bugs vs. Grub Worms: How to Tell Which One Is Killing Your Fort Worth Lawn
Chinch bugs feed on grass blades from above the soil and create irregular brown patches in the sunniest, hottest parts of the lawn, usually starting in May or June. Grub worms feed on grass roots from below and cause spongy, easily-lifted areas that may be pulled up by birds, raccoons, or skunks. The two are confused often, but the treatments are completely different.
Two Pests, Very Different Problems
If you are seeing dead patches in your lawn and you know it is not a watering or disease problem, you are probably dealing with one of two common North Texas pests: chinch bugs or grub worms. Both create brown areas, and both get blamed for each other's damage all the time. Treating the wrong one wastes money and lets the real culprit keep going. Here is how we tell them apart on Fort Worth, Keller, Aledo, and Benbrook properties.
Chinch Bugs
Feed on grass blades above the soil. Attack in the hottest, sunniest parts of the lawn. Damage peaks in July and August. Blades stay attached and intact. Active edge often shows a yellow halo.
Grub Worms
Feed on grass roots below the soil. Damage is more random, following where beetles laid eggs. Damage typically appears late summer or fall. Grass lifts like a loose carpet. Birds and skunks dig for them.
Where the Damage Shows Up
Chinch Bug Location
Chinch bugs love heat. They almost always start in the sunniest, hottest part of the yard — often along driveways, sidewalks, or south-facing exposures. The damage spreads outward from those hot spots in irregular patches.
Grub Worm Location
Grub damage is more random. Grubs distribute themselves across the soil based on where parent beetles laid eggs the prior fall, so you might see scattered dead spots throughout the yard rather than one expanding zone.
Seasonal Timing
Damage appearing in May or June is more likely chinch bugs. Damage appearing in September or October is more likely grubs. Chinch bug damage peaks in July and August; grub damage peaks in late summer and early fall.
What the Damage Looks Like
Chinch Bug Damage
Looks like the grass simply dried out and died, even when the lawn is being watered. The blades stay attached and intact for a while. The pattern often has a yellow halo at the active edge. Killed blades stay relatively rigid for weeks because only the leaf tissue was attacked.
Grub Worm Damage
Grab the affected grass and tug — large sections often lift up like a loose carpet because the roots have been chewed off. Walking across grub-damaged areas feels spongy underfoot. Grass goes mushy at the base. Birds, skunks, or raccoons digging is a near-certain indicator.
How to Confirm Which Pest You Have
Float Test for Chinch Bugs
Cut the bottom out of a coffee can, push it a couple of inches into the soil at the active edge, and fill with water. Chinch bugs will float to the surface within minutes. Adult chinch bugs are tiny (about 1/8 inch) and black with white wing markings.
Soap Flush for Chinch Bugs
Mix 2 tablespoons of dish soap into a gallon of water and pour over a one-foot square area at the boundary between green and yellowing grass. Chinch bugs surface within minutes. Counts of 10 or more indicate an active infestation needing treatment.
Dig Test for Grubs
Cut a 6-inch square of turf about 3 inches deep at the edge of an affected area and examine the soil. White, C-shaped larvae are grubs. Five or more grubs per square foot is generally the treatment threshold.
How Each One Is Treated
Treating one pest with the other's product or timing is a common mistake we correct. The active ingredients target different life stages and feeding behaviors.
Treating Chinch Bugs
Apply an insecticide labeled for chinch bug control at the active edge of the damaged area to stop the spread. The lawn should be slightly moist but not soaked. One properly timed application usually controls the population for the season. Best applied late spring through summer.
Treating Grub Worms
Apply a different category of soil insecticide and water it in to reach the larvae below the surface. The most effective window is late summer, when newly hatched grubs are young and feeding actively. Applying in spring on mature grubs gives much weaker control.
Recovery and Prevention
Recovering from Chinch Bugs
Chinch bug damage often recovers without reseeding if treated early. The grass blades may be dead but the crowns are usually still alive, so the lawn fills back in once the bugs are gone.
Recovering from Grubs
Grub damage frequently requires reseeding or sodding because the roots are gone. Most customers see better results when grub treatment is combined with light overseeding for cool-season blends or plugging for St. Augustine.
Prevention Going Forward
For chinch bugs: preventative spring applications and addressing thatch buildup. For grubs: preventative late-summer applications timed to the egg-laying window. On properties without a grub history, we monitor rather than treat preventatively.
Other Pests That Get Confused With These Two
Sod Webworms
Ragged irregular brown patches with chewed grass blades. Similar to chinch bug damage but caused by caterpillar feeding. Requires different active ingredients.
Armyworms
Expanding brown areas as they march across the lawn feeding. Can take down significant lawn area within days during outbreak years.
Mole Crickets
Damage the soil structure as they tunnel, producing soft spongy areas that look similar to grub damage. Less common in the Fort Worth area than further south.
Fire Ants
Kill grass directly under the mound but rarely produce widespread damage patterns. Easily identified by visible mounds and ant activity.
Not Sure What's Damaging Your Lawn?
If you have damage in your Fort Worth area lawn and you are not sure what is causing it, we are glad to come diagnose it. We will check for both pests, confirm which one — or whether it is something else entirely — and put together a treatment plan that actually solves what you are seeing.
