Chafer grubs are the larvae of chafer beetles, and they’re one of the most common causes of mysterious brown patches and torn-up turf in lawns. These C-shaped, white grubs live in the soil and feed on grass roots, often going unnoticed until the damage is severe or wildlife starts ripping up your lawn to eat them.
What Chafer Grubs Look Like
Chafer grubs have stout, white-to-gray bodies that curl into a distinctive C shape when at rest. They straighten out when crawling. Three pairs of legs cluster near an orange-brown head, and the rear end of the body often appears darker because of soil visible through the skin. Depending on species, a fully grown grub ranges from about ¾ inch to 2 inches long when straightened out.
Several species cause lawn damage. The European chafer and masked chafer are among the most widespread. Telling species apart requires a magnifier (10x or stronger) to examine the pattern of tiny bristles on the underside of the last abdominal segment, a feature called the raster pattern, which is unique to each species. For practical purposes, though, most homeowners don’t need to identify the exact species. If you’re pulling up loose turf and finding white, C-shaped grubs underneath, you have a chafer grub problem.
People sometimes confuse chafer grubs with leatherjackets, the larvae of crane flies. The difference is straightforward: chafer grubs have legs and a visible head capsule, while leatherjackets are legless, grayish-brown, and lack a distinct head.
How They Damage Your Lawn
Chafer grubs eat grass roots. As the root system is destroyed, patches of lawn turn yellowish and feel spongy underfoot. You can often peel back affected turf like a carpet because there are no roots anchoring it to the soil. Damage is most obvious between autumn and spring, when the grubs are largest and feeding most actively.
The grubs themselves are only half the problem. Birds (particularly crows, magpies, jays, and rooks), badgers, and foxes will tear up large sections of turf to reach the grubs underneath. This secondary damage from foraging animals is often far more dramatic and visible than the root feeding itself. You might wake up to find strips of lawn peeled back or scattered across the garden.
Damaging populations tend to be very localized and sporadic. One lawn on a street might be devastated while neighboring properties are untouched. European chafer in particular prefers dry, well-drained soils, so infestations are often heaviest in sunny areas, on slopes, or in sandy soil.
When Grubs Are Active
Adult chafer beetles emerge in early to midsummer, mate, and lay eggs in the soil. The eggs hatch within a few weeks, and the tiny grubs begin feeding on grass roots through late summer and autumn. As temperatures drop, they burrow deeper into the soil to overwinter. In spring, they move back toward the surface to resume feeding before eventually pupating and emerging as adult beetles to restart the cycle.
This timing matters for control. The best window to target chafer grubs is when they’re small and feeding near the surface, typically late summer through early autumn. By the time you notice severe damage in late autumn or winter, the grubs are larger, harder to kill, and may have already moved deeper into the soil.
Biological Control With Nematodes
The most widely recommended non-chemical treatment is applying parasitic nematodes, microscopic worms that infect and kill grubs in the soil. The species used against chafer grubs actively hunts its prey underground, making it well suited for targeting grubs that are spread through the root zone.
Success depends heavily on soil conditions. The nematodes need soil temperatures above 68°F (20°C) to be effective, which typically limits application to late summer or early autumn in most climates. They’re also sensitive to drying out, so you need to water the lawn before and after application, then keep the soil moist for at least two weeks. In heavy clay soils, nematodes may struggle to move through the ground, while sandy soils may need extra irrigation to prevent them from desiccating.
Apply nematodes in early morning or evening to avoid UV exposure from sunlight, which kills them quickly. They’re mixed into water and applied with a sprayer or watering can directly onto the soil. Research suggests a minimum density of roughly 24,000 nematodes per square foot for effective control. If you’re using a sprayer, agitate the solution every five minutes or so to keep the nematodes evenly distributed and supplied with oxygen. Most suppliers include specific instructions for mixing rates and application volumes.
Nematodes won’t produce the instant results of a chemical treatment. They work over days to weeks, and a single application may not eliminate every grub. But they pose no risk to pets, children, wildlife, or beneficial insects, which makes them the go-to choice for most home lawns.
Chemical Treatment Options
Professional-grade insecticides based on the active ingredient chlorantraniliprole are available for turf use and can provide season-long grub control with a single application in spring. This product is registered under the EPA’s Reduced Risk Program, meaning it meets criteria for lower risk to human health, non-target organisms, or the environment compared to conventional alternatives. It’s primarily used by lawn care professionals and golf course managers rather than homeowners.
Chemical options for homeowners vary by country and region. In the UK, for example, most chemical grub treatments have been withdrawn from amateur use, making nematodes and cultural practices the only realistic options. In parts of the US, products containing chlorantraniliprole or other active ingredients may be available at garden centers, but registration status varies by state and even by county. Check local regulations before purchasing.
Lawn Care Practices That Reduce Risk
Healthy, well-maintained turf can tolerate moderate grub populations without showing visible damage, and certain lawn care habits actively discourage chafer beetles from laying eggs in the first place.
Mowing height makes a real difference. Keeping grass at 3 to 4 inches tall promotes deeper root growth and a denser canopy that’s more resilient to root feeding. Short-cropped lawns are more vulnerable because there’s less root mass to absorb the loss. Proper fertilization supports this dense growth, giving the grass the resources to outpace grub damage.
Irrigation is perhaps the single most effective cultural control. European chafer beetles prefer laying eggs in dry soil, and infestations are rarely a problem in turf that’s watered regularly enough to keep the soil consistently moist. If your lawn is in a dry, sunny spot with sandy or well-drained soil, regular watering during summer does double duty: it discourages egg-laying and helps the grass recover from any feeding that does occur.
These practices also support a diverse community of soil organisms, including predatory beetles and other insects that naturally keep grub numbers in check. A biologically active lawn is far less likely to develop the kind of explosive grub populations that cause visible damage.
Repairing Grub-Damaged Turf
Once you’ve addressed the grub population, damaged areas usually need reseeding. Rake away dead grass and any loose debris, lightly fork or aerate the bare soil, and overseed with a grass mix appropriate for your conditions. Keep the newly seeded areas moist until the grass is established. Early autumn is ideal for reseeding in most climates because soil is still warm enough for germination, and the grass has time to establish roots before winter.
For areas where wildlife has torn up turf that still has intact roots, you can often press or roll the torn pieces back into place and water thoroughly. If the root system hasn’t been completely destroyed, the turf will usually reattach within a couple of weeks.