If you want to know how to get rid of cutworms, apply a targeted pesticide or biological control in the evening — that’s when larvae emerge from the soil to feed. The most effective options are Btk and spinosad for natural control, or bifenthrin for severe infestations.
Cutworms are moth larvae that cut grass and plant stems at the soil line overnight. Peak season is late spring through summer. If you wake up to patchy, wilted grass that looks clipped at the base, cutworms are a likely culprit.
If cutworms have already damaged your lawn, Lawn Love connects you with local lawn care professionals who can help it recover with mowing, seeding, and fertilization.
| Key takeaways |
|---|
| • Treat in late afternoon or evening, since cutworms hide in soil during the day. • Confirm the infestation first with the soapy water test (1 tbsp dish soap per gallon of water). • Natural options (Btk, spinosad, nematodes) work best on young larvae early in the season. |
How to spot cutworms
Before treating, confirm you’re dealing with cutworms and not another pest. They leave specific signs in lawns and garden beds.
What they look like
Cutworms are soft-bodied caterpillars, 1 to 2 inches long, that curl into a C-shape when you disturb them. They can be gray, brown, black, or greenish, sometimes with faint stripes or spots. They have smooth, greasy-looking skin and small, hard head capsules. You’ll almost always find them as larvae, not adult moths.
What cutworm damage looks like
Cutworms feed at night, chewing grass stems and crowns just above the soil. Signs to watch for:
- Patchy, wilted grass that looks clipped at the base, despite adequate watering
- More birds than usual. They show up fast when cutworms are near the surface
- Small round holes in the thatch where larvae burrow during the day
Cutworm damage usually starts as small, irregular patches of thinning or browning turf, not broad, uniform dead areas, says Dr. Douglas S. Richmond, professor and extension specialist at Purdue University in West Lafayette, Indiana. A key clue: grass blades often look clipped or chewed near the crown, almost as if cut. Because cutworms feed at night, damage can appear suddenly.
Not all cutworms do the same kind of damage.
- Glassy cutworms are translucent and greenish-white with an almost see-through skin. They stay underground and feed on roots.
- Variegated cutworms have mottled brown, gray, and yellowish markings. Unlike most cutworms, they climb trees, shrubs, and garden plants and eat just about everything.
Young, tender plants take the worst hit. Adult moths don’t harm grass or plants at all.
Read more: Signs of Lawn Pest Damage vs. Disease vs. Drought Stress
How to test for cutworms
Scout at dusk, after dark, or early in the morning, when cutworms are most likely feeding or near the surface. During the day, they hide in the thatch or upper soil. Two quick ways to confirm cutworms before you start treating:
- Soapy water test. Mix 1 tablespoon of dish soap with 1 gallon of water, pour it over a suspect patch in the evening, and wait a few minutes. Cutworms will wriggle to the surface.
- Dig test. Check around damaged plants and sift through the top inch of soil near grass crowns. Larvae burrow into the thatch or use aeration holes to hide during the day.
“The most common mistake is treating before confirming the cause,” Richmond says. Homeowners often see a brown patch and reach for insecticide when the real culprit is disease, drought stress, dog urine, or another pest entirely. Confirm first, then treat.
How many is too many? That depends on your lawn’s health.
- Stressed or thin lawns: Treat at 2 to 6 larvae per square yard (NC State Extension). This is a conservative, early-action threshold.
- Healthy, well-watered lawns: Treat at 10 to 15 per square yard when you see visible damage (USU Extension).
Richmond says that in many home lawns, cutworm damage is localized and temporary, and healthy turf often recovers on its own. Natural enemies like ground beetles, birds, and parasitic insects help keep populations in check. Treatment is justified when you’re still finding active larvae and the lawn is continuing to lose turf.
How to get rid of cutworms naturally
If you catch the infestation early, start with natural and organic options. Natural methods work best on young larvae. If damage is already widespread, skip ahead to the pesticides section or combine both approaches.
Natural cutworm treatment comparison
| Treatment | Results | Best for |
| Nematodes | 2–5 days | Soil-stage larvae |
| Diatomaceous earth (DE) | 3–7 days | Dry conditions, mild infestations |
| Bacillus thuringiensis kurstaki (Btk) | 2–4 days | Young larvae, most selective |
| Spinosad | 1–2 days | Most infestations, pollinator-safe |
Beneficial nematodes
Beneficial nematodes are microscopic organisms that hunt cutworm larvae in the soil, infect them, and kill them within days. Safe for people, pets, and beneficial insects.
- Where to buy: Local nurseries, online retailers, farm supply stores
- Estimated cost: $20 to $40 per package
- How to apply: Mix with water, apply with a sprayer or watering can. USU Extension recommends 25 million nematodes per 1,000 sq ft
- When to use: Early spring or late summer in moist soil. Apply morning or evening to protect from UV
Pro tip: Beneficial nematodes need moist soil to survive. Water the area the day before you apply them.
Diatomaceous earth
Diatomaceous earth (DE) is a fine powder made from fossilized algae. It scratches through cutworm exoskeletons and dries them out. Use food-grade DE only. Safe for people, pets, and the environment.
- Where to buy: Garden centers, online stores, pet stores
- Estimated cost: $20 to $50 per bag
- How to apply: Duster or spreader for even coverage
- When to use: Dry conditions, early morning or evening. Wet DE doesn’t work
Bacillus thuringiensis kurstaki (Btk)
Btk is a naturally occurring bacteria that kills caterpillars by disrupting their digestive system. It doesn’t harm beneficial insects like bees, ladybugs, or predatory beetles, making it the most selective option in this list.
- Where to buy: Garden centers, nurseries, online retailers, farm supply stores
- Estimated cost: $10 to $30 per bottle, larger quantities upwards of $80
- How to apply: Sprayer or watering can
- When to use: When cutworms are young; Btk works best on small larvae
Spinosad
Spinosad comes from Saccharopolyspora spinosa bacteria and attacks cutworm nervous systems. It spares most beneficial insects as long as you don’t spray midday when pollinators are out. Safe around family and pets.
- Where to buy: Garden centers, nurseries, online shops
- Estimated cost: $20 to $30 per bottle
- How to apply: Sprayer or watering can
- When to use: Early morning or evening; wait at least 7 days between applications
Birds
Robins, sparrows, and other insect-eating birds are natural cutworm predators. Attract them to your yard with bird feeders, birdbaths, native shrubs, and berry-producing plants.
Pesticides that work against cutworms
If you’re not seeing results from natural methods after 7 to 10 days, it’s time to try something stronger: pesticides. Apply in late afternoon or evening when cutworms emerge to feed.
Chemical cutworm treatment comparison
| Treatment | Results | Best for |
| Cutworm bait | 1–3 days | Targeted surface feeding |
| Bifenthrin | A few hours to 2 days | Severe infestations |
| Carbaryl | A few hours | Last resort only |
Cutworm bait
Granular baits with spinosad or bifenthrin are made for cutworms and other surface-feeding caterpillars. Scatter them in the evening so they’re ready when larvae emerge. Baits target surface feeders specifically, so the risk to beneficial insects is minimal compared to broadcast sprays. They work well for targeting problem patches near garden beds or spots where spray coverage is tricky.
- Where to buy: Garden centers, farm supply stores
- Estimated cost: $15 to $30 per bag
- How to apply: Broadcast spreader or by hand, in the evening
- When to use: Active feeding periods in spring or summer
Bifenthrin
Bifenthrin is a fast-acting pyrethroid with a longer residual than most alternatives. It also poses risks to pollinators and beneficial insects, so avoid applying near flowers or when pollinators are active.
- Where to buy: Garden stores, farm supply centers, online retailers
- Estimated cost: $15 to $30, bulk around $100+
- How to apply: Sprayer or broadcast spreader
- When to use: Early spring or summer during active feeding
Carbaryl
Carbaryl kills cutworms on contact and by ingestion. It’s effective but also harms bees, ladybugs, parasitic wasps, lacewings, and earthworms. Use as a last resort.
- Where to buy: Garden centers, online stores
- Estimated cost: $20 to $200, depending on quantity
- How to apply: Sprayer or dust applicator
- When to use: Early season or at first sign of damage
Lawn maintenance practices that control cutworms
Good lawn care reduces the conditions cutworms need to thrive. These practices won’t eliminate an active infestation on their own, but they matter for prevention.
Mow properly
Mow to the right height for your grass type. Cut too short, and you stress the grass, which makes it easy pickings for pests. Leave it too tall, and you’re giving cutworms the shady, humid cover they love. Switch up your mowing direction and timing to keep them guessing.
Pro tip: A few extra mows during cutworm season won’t eliminate an active infestation, but they reduce cover and keep larvae more exposed.
Read more:
Water correctly
Water deeply and less often. Deep watering builds deeper roots, which makes your lawn tougher overall. It also pushes cutworms toward the surface, where birds can pick them off.
Aim for about 1 inch per week (including rain), applied in the early morning. Avoid overwatering. Soggy soil helps cutworms hide and can attract grubs and lawn fungus.
Pro tip: Water a patch of lawn before sunset, then grab a flashlight. If cutworms are present, you’ll see them surface.
Read more:
Limit outdoor lighting
Adam G. Dale, associate professor and associate chair at the University of Florida Extension, says cutworm moths are attracted to bright lights at night. Turn off outdoor lights when you can, or switch to motion-activated lighting. Fewer moths mean fewer eggs.
My tip: If you need outdoor lights for safety, try red lights. Moths can’t see them.
Remove leaves and debris
Cutworms shelter in leaf piles, grass clippings, and thatch during the day. Regular raking and dethatching strips away their cover. Aerating in spring or fall keeps thatch in check and your grass healthier overall.
My tip: Clear leaves the same day they fall, or within 48 hours at most. Even a couple of days is enough for pests to move in.
Read more: How to Get Rid of Armyworms
FAQs
Yes. Small patches usually fill in within a few weeks with proper watering and fertilization. Moderate damage may need overseeding. Large dead patches where cutworms destroyed grass crowns may require reseeding or sod.
No grass type is immune. NC State Extension says black cutworms target closely mowed bentgrass and Poa annua, both mostly golf course grasses, and that Kentucky bluegrass is a non-preferred host. For home lawns, keeping your grass healthy matters more than the species you’re growing.
Neem oil can disrupt cutworm development and deter egg-laying, but it won’t knock out an active infestation. For prevention, mix 1 teaspoon of neem oil with 4 cups of water and a small amount of dish soap, then spray problem areas in the evening. For active infestations, pair neem with Btk or spinosad.
Get your lawn back on track
Cutworms can do real damage before you even realize they’re there. But once you have the infestation under control, local lawn care professionals can help your lawn recover with mowing, fertilization, and seeding so it comes back thicker and healthier than before.
Read more:
How to Get Rid of Sod Webworms
Common Spring Lawn Pests
What is Overseeding?
Main Image: A green cutworm caterpillar curls up on a leaf. Photo Credit: Diane N. Ennis / Adobe Stock
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