How to Get Rid of Lawn Grubs (and Prevent Them)

If sections of your lawn are turning brown for no obvious reason, the grass feels spongy underfoot, or skunks and birds keep tearing up the turf overnight, lawn grubs are a prime suspect. These plump white larvae feed on grass roots just below the surface, and a heavy infestation can kill large patches in a matter of weeks. The good news: grubs are easy to confirm, easy to count, and very treatable once you understand the timing.

Part of our Pest Control guide →

In this guide

1. What are lawn grubs?
2. Signs you have a grub problem
3. The tug-and-dig test to confirm grubs
4. Treatment options: preventive vs curative
5. Organic and natural grub control
6. How to apply and water in grub treatments
7. Preventing grubs with a healthy lawn
8. Frequently asked questions

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What are lawn grubs?

Lawn grubs (often called white grubs) are the larval stage of several beetles, most commonly Japanese beetles, June beetles (also called May beetles), and European chafers and masked chafers. The adult beetles lay eggs in your turf during summer, and the eggs hatch into C-shaped, creamy-white larvae with tan heads and visible legs near the front. They live in the soil just beneath the grass and spend their days eating grass roots.

Because grubs sever the roots that anchor and feed your grass, infested turf loses its ability to take up water and nutrients. That is why grub damage often looks like drought stress at first, even when you have been watering. Understanding this life cycle is the key to timing treatment correctly, which we cover below. Grub control is one piece of a healthy lawn program alongside your lawn fertilizer schedule and overall outdoor living guide.

The grub life cycle in brief

• Early-to-mid summer: Adult beetles emerge, mate, and lay eggs in the lawn.
• Mid-to-late summer: Eggs hatch into tiny, hungry young grubs that feed near the surface — this is when damage starts.
• Fall: Grubs grow large and feed heavily, then burrow deeper as the soil cools.
• Spring: Grubs move back up to feed briefly before pupating into adult beetles, completing the cycle.

Signs you have a grub problem

A few grubs are normal in any healthy lawn and cause no harm. The signs below point to a population large enough to act on, especially when you see several of them together.

• Irregular brown patches that appear in late summer or fall and keep spreading, even with adequate watering.
• Turf that lifts like a carpet or loose sod — because the roots have been chewed away, the grass detaches easily from the soil.
• A spongy, springy feel when you walk across the affected area.
• Animals digging — skunks, raccoons, moles, and birds tear up the lawn at night to feast on the grubs, leaving small holes and flipped-up sod.
• Wilting grass that does not green up after rain or irrigation.

Grub damage is easy to confuse with other problems such as drought, fungal disease, or pet urine. Brown spots that are not caused by grubs may need overseeding instead — see our guide on how to fix bare spots in lawn once the underlying cause is handled. The surest way to tell grubs apart is to dig and count.

The tug-and-dig test to confirm grubs

Before you buy any product, confirm that grubs are actually the problem and that there are enough of them to justify treatment. This takes about ten minutes.

How to do the test

1. Tug test first: Grab a handful of the affected grass and pull. If it lifts away easily like a loose rug, the roots are gone — a strong grub indicator.
2. Cut a square: Using a spade, cut three sides of a 1-foot-by-1-foot square about 2 to 3 inches deep at the edge of a damaged patch, then fold it back.
3. Count the grubs: Sift through the soil and roots and count the C-shaped white larvae you find.
4. Check several spots: Repeat in two or three locations, including the edges of brown patches where active feeding happens, and average your counts.
5. Replace the sod: Fold the flap back down, press it in, and water it so it re-roots.

Reading the threshold

• 0-4 grubs per square foot: Normal. No treatment needed in a healthy lawn.
• 5-10 grubs per square foot: The action threshold for most lawns. Treat, especially if the grass is already thin or stressed.
• 10+ grubs per square foot: A heavy infestation that will cause visible damage. Treat promptly.

A vigorous, well-fed lawn can tolerate more grubs than a thin one, so a dense lawn might shrug off 8 grubs while a struggling lawn shows damage at 5.

Treatment options: preventive vs curative

The single most important factor in grub control is timing. Products fall into two categories, and using the wrong one at the wrong time wastes money and may not work at all.

Preventive control (apply early summer)

Preventive products containing chlorantraniliprole (and older options like imidacloprid) are applied before or around egg-hatch — roughly late spring through mid-July in most regions. They settle into the soil and kill the tiny young grubs as they begin feeding. Chlorantraniliprole is a popular choice because it has a low impact on bees and other beneficial insects when used as directed. Apply it once early in the season as insurance if you had grubs last year or live in an area with heavy beetle pressure. Browse preventive grub control products to compare options.

Curative control (apply late summer to early fall)

If you already have active grubs and a count above the threshold, you need a fast-acting curative product. Trichlorfon is the most common curative active ingredient — it works on the larger, actively feeding grubs present in late summer and early fall. Curative products are not a long-term preventive; they knock down the current population quickly. Apply when grubs are young and feeding near the surface (typically August through September), because large fall grubs and dormant spring grubs are much harder to kill. You can find curative grub killer at most garden retailers.

Quick timing cheat sheet

• You had grubs last year and want insurance: Apply a preventive (chlorantraniliprole) in late spring or early summer.
• You see damage and confirmed grubs now (late summer/fall): Apply a curative (trichlorfon).
• It is spring and you see grubs: Wait. Spring treatments are unreliable; plan a preventive for early summer instead.

Organic and natural grub control

If you prefer to skip synthetic insecticides, two biological options can suppress grubs, though they work more slowly and benefit from patience.

Beneficial nematodes

Beneficial nematodes (look for Heterorhabditis bacteriophora) are microscopic worms that hunt down and infect grubs in the soil. They are most effective applied in late summer or early fall against young grubs, when the soil is warm and moist. Nematodes are living organisms, so buy fresh stock, apply in the evening or on a cloudy day to avoid UV light, and water the lawn before and after application to move them into the root zone. Shop for beneficial nematodes and follow the package storage instructions closely.

Milky spore

Milky spore (Paenibacillus popilliae) is a naturally occurring bacterium that specifically targets Japanese beetle grubs. Once applied, it can establish in the soil and provide long-term suppression for years. The catch: it works only on Japanese beetle larvae (not other beetle species), and it can take a few seasons to build up enough spore concentration to make a noticeable dent. Think of milky spore as a slow, long-game tool rather than a quick fix.

How to apply and water in grub treatments

Almost every grub product — synthetic or organic — needs to reach the soil where the grubs live, and that means watering it in. The application is just as important as the product choice.

• Read the label rate. Apply granules or liquid evenly across the lawn at the labeled rate using a spreader or hose-end sprayer.
• Water it in immediately. Most products need about 0.5 inch of water right after application to carry the active ingredient down into the root zone. Skipping this step is the most common reason treatments fail.
• Mow first if needed. Cutting the grass before application helps the product reach the soil surface.
• Keep the area moist for nematodes — they die out if the soil dries between application and establishment.
• Wear gloves and keep kids and pets off the lawn until granules are watered in and the surface is dry, per the label.

Preventing grubs with a healthy lawn

The best long-term defense against grubs is a thick, deeply rooted lawn that can tolerate a modest grub population and recover quickly from feeding. Cultural practices matter as much as any product.

• Water deeply and infrequently. Frequent shallow watering keeps the surface moist, which is exactly where beetles prefer to lay eggs. Deep, occasional watering encourages deep roots that withstand grub feeding. During peak egg-laying in midsummer, letting the surface dry out can even reduce egg survival.
• Mow high. Keeping cool-season grasses around 3 to 4 inches shades the soil and supports deeper roots, making the lawn more resilient.
• Feed appropriately. A balanced feeding program builds density without overdoing nitrogen. Follow a sensible lawn fertilizer schedule and choose from the best lawn fertilizers for your grass type.
• Overseed thin areas so there are no weak, sparse patches for damage to take hold.
• Aerate compacted soil to promote strong root growth and better water movement.

You do not need to apply preventive insecticide every year by default. Reserve preventive treatments for lawns with a confirmed history of grub damage, and let scouting (the dig test) guide curative treatment for everyone else.

Frequently asked questions