If you are searching for sod webworm damage pictures, the key detail is not the insect itself, but the pattern it leaves behind in the grass. Sod webworm damage shows up as small, ragged brown patches, thinning turf, and chewed blades that look scraped or frayed at the tips. Catching that pattern early lets you treat the lawn before the damage spreads across a larger section.
What Sod Webworm Damage Looks Like
Sod webworms feed on grass blades at night and hide in the thatch during the day, so the first sign is usually turf that looks dried out even after watering. The damaged grass turns brown, thin, and uneven, with patches that can start as small circles and merge into larger irregular spots. In strong sun, the lawn can look scorched from a distance.
Look closely at the blades. Sod webworm damage leaves a shredded, clipped look, not clean-cut edges. You may also see small green pellets of frass, which are insect droppings, near the base of the grass. If the area gets worse after hot evenings, that is a strong clue you are dealing with sod webworms damage, not a simple watering issue.
Signs that separate sod webworm damage from drought
Drought stress affects larger areas and the grass blades stay intact, just curled and dull. Sod webworm feeding leaves patchy spots with visible chewing and a rough texture. If you pull on the grass in a damaged area, the roots stay in place, but the top growth looks heavily grazed. That difference matters because drought and webworm damage need different fixes.
Where to Look First in the Lawn
Start in the sunniest, driest parts of the yard, since sod webworms feed most heavily there. Check along sidewalks, driveways, curb edges, slopes, and areas with thin turf. These spots heat up faster and show damage first. New sod, overfertilized lawns, and lawns with heavy thatch also attract more feeding.
Inspect the lawn in late afternoon or early evening, then again at dusk. Webworms are more active at night, and you may see moths flying low over the grass. During the day, damage can be hard to connect to the pest unless you look closely at the pattern and the blade tips.
How to Check for Sod Webworms
A simple inspection will tell you a lot. You do not need special equipment, just a knife, a bucket, and a flashlight. Use the steps below when you spot suspicious brown patches.
- Cut a one-foot square section of turf at the edge of the damaged area.
- Fold the sod back and look into the thatch layer, right above the soil.
- Search for small green, brown, or gray caterpillars curled in a C shape.
- Look for silky webbing, pellet-like droppings, and chewed grass stems.
- Walk the lawn at dusk with a flashlight and watch for larvae moving across the grass.
Finding even a few larvae in the thatch confirms the cause. If you only see brown turf with no feeding sign, check irrigation, compaction, or fungus before treating for insects.
What Sod Webworms Look Like
Sod webworm larvae are small caterpillars, usually about half an inch long when mature. They blend into the thatch, so they are easy to miss. Their color ranges from light tan to greenish or gray, and they move with a wriggling motion when disturbed. The adult moths are small and tan, with narrow wings and a resting posture that looks like a tiny triangle.
The larvae cause the damage, not the moths. If you see moths rising from the lawn in the evening, that is a sign the infestation is active and egg laying is underway. The most important clue is still the turf injury, because the insects themselves hide well during the day.
How to Treat Sod Webworm Damage
Treat the lawn as soon as you confirm active feeding. Start with irrigation, because stressed grass recovers better and insecticides work better when turf is not bone dry. Water the lawn deeply in the morning to bring the grass out of stress, then apply treatment to the feeding areas according to label directions.
Best treatment approach for homeowners
Use a lawn insecticide labeled for sod webworms, with ingredients such as bifenthrin, cyfluthrin, lambda-cyhalothrin, or carbaryl, depending on what your local store carries and what your lawn label allows. Apply in the late afternoon or early evening so the product reaches active larvae. Follow the label rate exactly, and water in only if the label directs it.
For a lighter infestation, bacillus thuringiensis var. kurstaki, or Bt, works on young caterpillars when they are actively feeding. It needs direct contact with the larvae as they eat treated grass. Mowing before treatment helps expose the thatch layer and lets the product reach the feeding zone.
How to Prevent Sod Webworms from Coming Back
Healthy turf resists damage better than stressed turf. Keep the lawn mowed at the correct height for your grass type, and avoid scalping it. Remove excess thatch if it is thicker than half an inch, because that layer gives webworms a protected place to hide and feed.
Do not overfertilize in late spring or summer. Fast, tender growth attracts more feeding and makes damage show up faster. Water deeply and less often, and inspect vulnerable spots every week during warm months. If you see moth activity plus fresh chewing, treat early instead of waiting for more brown patches to appear.