How to Get Rid of Grubs in Your Lawn

Grubs are the white, C-shaped larvae of several beetle species — most commonly Japanese beetles, June bugs (June beetles), and chafer beetles. Adult beetles lay their eggs in lawn soil during late June and July. The eggs hatch into small grubs that spend late summer and early fall feeding aggressively on grass roots just below the soil surface before burrowing deeper for winter.

The damage happens because grubs sever the root system entirely. Grass with no roots can't uptake water or nutrients, and it dies quickly in the heat of late summer. The sod literally comes loose from the ground — which is why heavily infested areas pull up in sheets, often revealing hundreds of grubs writhing in the exposed soil.

Beetle species that cause grub problems:

• Japanese Beetles — the most widespread grub pest across the eastern U.S.; adults are distinctive with copper and green coloring
• June Bugs (May beetles) — large brown beetles common in warm climates; larvae are thick and especially damaging
• European Chafer — particularly damaging in northern states; adult emergence in June is the window for egg-laying prevention
• Masked Chafer — common in the Midwest; similar life cycle to Japanese beetles
• Oriental Beetle — expanding range across the mid-Atlantic; less visible adults but destructive larvae

Knowing which beetle is responsible in your area helps with timing, since the egg-laying and larval feeding windows vary slightly by species. Japanese beetles in most regions lay eggs in July, with grubs peaking in August and September. Your local cooperative extension office can confirm what's prevalent in your zone.

The challenge with grubs is that damage often isn't visible until midsummer, when populations have grown large enough to cause widespread root destruction. Catching them early — or preventing them before they hatch — is far more effective than reacting to visible damage. Here's what to watch for at each stage.

Early warning signs (July–August):

• Irregular patches of lawn that look drought-stressed even with adequate water
• Increased bird activity — starlings, robins, and crows pecking the lawn are hunting grubs
• Skunks and raccoons digging up sections of turf overnight to feed on grubs
• Spongy, soft feeling underfoot in isolated areas

Confirmed damage signs (August–October):

• Brown dead patches that don't respond to watering — roots have been severed
• Turf that rolls back easily like a carpet with no resistance
• Visible white C-shaped larvae 1/2 to 1 inch long in the top 2–3 inches of soil
• More than 5–10 grubs per square foot indicates a damaging level infestation

To confirm grubs, cut and peel back a 1-square-foot section of turf in a suspect area and examine the soil. Count the grubs. A threshold of 5 or more per square foot in cool-season grasses (or 8–10 per square foot in warm-season grasses) is generally considered worth treating. Fewer than that and your lawn may tolerate the population without significant damage.

Grub control products fall into two categories: preventive and curative. The right choice depends on where you are in the season. Preventive products are applied before eggs hatch and work best on young larvae. Curative products are applied to existing grub populations later in the summer and fall. Using the wrong type at the wrong time significantly reduces effectiveness.

Water is critical with any grub control product. Most granular treatments need to be watered in immediately after application — at least 1/2 inch of irrigation. This moves the active ingredient into the root zone where grubs feed. Without adequate watering, the product sits on the surface where it's far less effective.

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Once you've treated the grub population, the dead patches in your lawn need to be reseeded. Grub damage creates bare spots that weeds will quickly colonize if left untreated. Early fall (September into early October) is the best window for repair — temperatures are cooler, soil retains moisture better, and grass seed germinates quickly with less competition from summer weeds.

Lawn repair steps after grub treatment:

• Rake out dead grass and debris to expose bare soil — don't skip this step
• Loosen the top inch of soil with a hand rake or dethatching rake to improve seed-to-soil contact
• Amend with a thin layer of compost or lawn soil to improve the growing medium
• Spread grass seed appropriate for your lawn type — match the existing grass variety if possible
• Lightly rake seed in and tamp down gently with the back of a rake
• Apply a starter fertilizer to support root development on new seedlings
• Keep the seeded area consistently moist until germination (7–21 days depending on variety)
• Reduce watering frequency but increase depth once seedlings are 1–2 inches tall

One common mistake is rushing to apply a weed killer over reseeded areas. Most herbicides — including pre-emergent crabgrass preventers — will kill or inhibit grass seedlings. Wait until new grass has been mowed at least 2–3 times before applying any weed control product to those areas.