To get rid of grubs in your yard, identify the species first (Japanese beetle, June beetle, and chafer grubs are the most common), apply beneficial nematodes in spring or fall as a natural treatment, or use milky spore (slower but lasts years), or chemical grub killer (imidacloprid or chlorantraniliprole) for severe infestations. Treat in late summer to early fall when grubs are young and near the surface. Prevention beats cure: a thick, healthy lawn naturally resists grub damage.
What are grubs and why they damage lawns
Lawn grubs are the larval stage of various beetle species. The most common in US lawns:
- Japanese beetle grubs — the most common lawn pest. Adults are metallic green/copper beetles that swarm in summer. Grubs feed on grass roots through fall and spring.
- June/May beetle grubs — larger grubs, 1-2 year lifecycle. Common in the Midwest and South.
- European chafer grubs — major problem in the Northeast. Heaviest feeders.
- Northern masked chafer — similar damage to Japanese beetles but slightly different timing.
- Asiatic garden beetle — smaller grubs, often go unnoticed until lawn damage appears.
All look similar: C-shaped, white to cream-colored, brown head, 6 legs near the head. ½-1 inch long when mature.
The damage: grubs feed on grass roots underground. Affected lawn areas turn brown, feel spongy when walked on, and can be pulled up like a loose rug (because there are no roots holding it down). Damage is most visible in late summer (August-September) and early spring.
How to tell if you have a grub problem
Confirm grub damage before treating. False alarms are common — many other lawn problems look similar.
The pull-up test: Grab a section of dying grass and pull. If it lifts up like loose carpet with no resistance, grubs are likely. If it stays rooted, the problem is something else.
The dig test: Cut a 12″×12″ square of sod with a spade and lift it. Count the grubs visible in the soil beneath. The threshold for treatment:
- 0-4 grubs per square foot: healthy lawn handles this naturally. Don’t treat.
- 5-9 grubs per square foot: borderline. Treat if damage is visible.
- 10+ grubs per square foot: definitely treat. Damage is imminent or already occurring.
Other signs: increased animal activity (skunks, raccoons, birds digging up your lawn), brown patches that don’t respond to watering, large flocks of starlings probing the grass.
When to treat for grubs
Timing matters more than which product you choose. Treat at the wrong time and even the best product won’t work.
- Late July to mid-September: ideal window. Grubs are small and near the surface, where treatments reach them easily.
- Early spring (April-May): second-best window. Grubs are active again after winter but still near the surface.
- Avoid: mid-summer (June) when grubs aren’t there yet, and mid-fall through winter when grubs burrow deep below treatment depth.
Natural treatments
Beneficial nematodes
Microscopic worms that hunt and kill grubs. Effective and completely safe for kids, pets, and beneficial insects.
- Species to use: Heterorhabditis bacteriophora (Hb nematodes) for white grubs
- Application: Mix with water, apply with a sprayer. Soil must be moist before and after application.
- Cost: $20-40 for treating 1,000-2,500 sq ft
- Effectiveness: 70-90% reduction when applied correctly
- Storage: living organisms — refrigerate until use, apply within a few days of receiving
Milky spore
A bacterial disease that infects Japanese beetle grubs specifically (not effective against other species). Once established in the soil, milky spore reproduces and provides ongoing protection for 10-15 years.
- Effectiveness: only works on Japanese beetle grubs
- Time to effect: 1-3 years to build up sufficient spore concentration
- Cost: $30-50 for a 1-lb container treating ~7,000 sq ft
- Long-term value: high — once established, protection lasts a decade or more
Encourage natural predators
- Birds: starlings, robins, and grackles eat grubs aggressively. Don’t discourage them in problem areas (even if they’re tearing up the lawn — that’s the cure for the disease).
- Beneficial insects: ground beetles and certain wasps prey on grubs.
- Healthy soil microbes: rich soil with diverse microbial life naturally suppresses grub populations.
Chemical treatments
For severe infestations (10+ grubs per square foot), chemical treatments work faster than natural options.
- Imidacloprid (sold as Merit, Scotts GrubEx with imidacloprid): preventive treatment, applied early summer before grubs hatch. Effective for entire season.
- Chlorantraniliprole (Scotts GrubEx): season-long preventive, lower toxicity than imidacloprid. Most modern grub products use this.
- Trichlorfon (Dylox): curative treatment for active infestations. Kills existing grubs within 1-2 weeks. Apply only when grubs are already present and damage is visible.
- Carbaryl (Sevin): less commonly used today; broad-spectrum insecticide.
Application notes:
- Water in immediately after application — granules need to reach soil where grubs live
- Apply when rain is expected or water with ½ inch of irrigation
- Keep pets and kids off the lawn until dry
- Note: imidacloprid is harmful to bees — avoid applying when lawn is in bloom (white clover, etc.)
Repairing grub damage
After eliminating the grubs, repair the lawn:
- Remove dead sod — pull up the loose carpet of dead grass
- Loosen the soil — rake or rotary cultivator to break the surface
- Topdress with quality soil — ¼-½ inch of lawn soil over the prepared area. See our lawn soil vs topsoil guide
- Reseed or sod — match your existing grass species. Sod recovers faster; seed is cheaper
- Water consistently — keep soil moist (not soaked) for 14-21 days during establishment
Long-term grub prevention
- Maintain a healthy lawn — proper mowing height (3 inches+ for most grasses), deep watering, balanced fertilization. Strong roots resist grub damage
- Core aerate annually — reduces compaction, improves root depth, makes lawns more resilient
- Skip the perfect lawn — a yard with diverse plant life (clover, dandelions) supports natural predators
- Time irrigation — beetles prefer to lay eggs in moist soil. Reducing irrigation in late June through July (when adults are laying eggs) can reduce next year’s grub population
- Reduce porch and yard lighting — adult beetles are attracted to lights at night, then lay eggs nearby
Frequently asked questions
Do I have grubs or just dead grass?
Pull up a section of dying grass. If it lifts like a rug with no roots, it’s grubs. If it stays rooted, the problem is drought, disease, or fertilizer burn — different fixes apply.
Will grubs go away on their own?
Small populations (under 5 per square foot) yes — healthy lawns handle them. Heavy infestations (10+) won’t resolve naturally and need treatment.
Is Scotts GrubEx safe for pets?
When applied per label and watered in, yes — once dry, pets can return to the lawn. Keep pets off during application and until granules are watered in and dry. Never let pets eat treated granules directly.
Can I treat for grubs and overseed at the same time?
Yes — fall is the ideal time for both. Apply grub treatment first, water in, then overseed 1-2 weeks later. Some products are safe for new seed immediately; check labels.
Are grubs harmful to humans or pets?
No. Grubs don’t bite, sting, or transmit diseases. The damage is only to lawn turf.
Find lawn care suppliers near you
Need to repair grub damage with fresh sod or quality lawn soil? Topsoil.com lists landscape suppliers across the US who carry sod, topsoil, and lawn soil blends.
Related guides: Lawn Soil vs Topsoil, How to Make Well-Drained Soil.
