White grubs in lawns

White grub beetles and other lawn insects

Japanese Beetle Popillia japonica The Japanese beetle damages landscapes twice: metallic green adults chew the leaves, flowers and fruit of hundreds of plants in early summer, and their white grubs feed on grass roots underground. A review of its biology calls it the most widespread and destructive insect pest of turf, landscapes and nursery crops in the eastern United States. Masked Chafers Cyclocephala species (northern masked chafer, C. borealis; southern masked chafer, C. lurida) Masked chafers are native North American beetles whose larvae, called white grubs, feed on turfgrass roots. The adults don't feed at all; the grubs do the damage, mostly in late summer and fall. May and June Beetles Phyllophaga species May and June beetles, or June bugs, are native scarab beetles in the genus Phyllophaga. The adults buzz around porch lights on early summer nights, while their C-shaped grubs feed on roots, mostly in turf. European Chafer Amphimallon majale The European chafer is an invasive beetle whose C-shaped white grubs are a severe pest of lawns. The grubs feed longer during the year than Japanese beetle grubs, so they are considered more destructive to turf. Green June Beetle Cotinis nitida Green June beetles are large, metallic green scarabs that cruise a few feet above lawns on summer days with a loud buzz. They are harmless to people; the adults damage ripe fruit, and their oversized grubs burrow in lawns rich in organic matter. Oriental Beetle Anomala orientalis (Exomala orientalis) The oriental beetle (Anomala orientalis, also placed in the genus Exomala) is a small scarab from Asia whose white grubs chew the roots of turf and ornamental plants. It is considered the most serious grub pest of turf and woody ornamentals on Long Island, in northern New Jersey and in Connecticut, and in parts of the Northeast most lawn grubs turn out to be oriental beetles rather than Japanese beetles. Asiatic Garden Beetle Maladera formosae (long known as Maladera castanea) The Asiatic garden beetle is an imported scarab about the size and shape of a coffee bean. It hides in the soil by day and comes out at night to shred leaves and flowers, and it is so drawn to lights that it can gather in large numbers on windows and screen doors. Black Turfgrass Ataenius Ataenius spretulus The black turfgrass ataenius is a small scarab beetle whose tiny white grubs feed on grass roots. It is mainly a golf course pest of greens, tees and fairways, and it only occasionally damages home lawns. Ten-lined June Beetle Polyphylla decemlineata The ten-lined June beetle is a big, striped scarab of the western U.S. and Canada. Males fly to lights on summer nights and the beetles can hiss loudly when disturbed, but Colorado State calls them harmless. In yards the grubs rarely cause noticeable injury, though in some orchards and new poplar plantings they kill trees. Sugarcane Beetle Euetheola humilis (syn. E. rugiceps) The sugarcane beetle is a native black scarab beetle whose adults damage bermudagrass, zoysiagrass and other lawns by digging and feeding at the roots and crowns. Billbugs Sphenophorus species, e.g., S. parvulus (bluegrass billbug) and S. venatus vestitus (hunting billbug) Billbugs are small weevils with a long snout. Their legless grubs bore inside grass stems and later feed on crowns and roots, killing scattered patches that are one of the most commonly misdiagnosed lawn problems.

What white grubs are

• White grubs are the larval stage of several different scarab beetles. The beetles go through egg, grub, pupa and adult; the grub goes through three larval stages, so grubs of various sizes are often found in the soil together.^[2]
• Most turf-feeding grubs curl into a C shape when dug out. They are dirty white and soft-bodied with a brown head and three pairs of well-developed legs; green June beetle grubs are the exception, with short legs, and they rarely curl.^[2][6][8]
• Which species you'll find depends on the region. Clemson lists Japanese beetles, masked chafers, May and June beetles and green June beetles in the Southeast; NC State adds the northern masked chafer and Asiatic garden beetle. In Pennsylvania lawns, Japanese beetles and northern masked chafers are the main damaging grubs, with Asiatic garden beetle, European chafer, green June beetle, May and June beetles and Oriental beetle turning up occasionally.^[2][7][6]
• Clemson also names two scarabs that are slowly expanding their range in the Southeast: the black turfgrass ataenius and the Oriental beetle.^[2]
• Japanese beetles, masked chafers and green June beetles have a one-year life cycle. May and June beetles take longer: two to three years according to Clemson, while Penn State gives the common May or June beetle a three-year cycle.^[2][6]
• For the annual species, UMass describes a similar year: adults fly in early summer and lay eggs from late June to late July, grubs feed on roots from early July through mid autumn and again in spring, and adults emerge the next summer. The European chafer runs about two weeks ahead of the others.^[9]
• Not every grub in the soil is a pest. UW-Madison Extension says most white grubs in the Midwest are beneficial scavengers that help break down organic matter.^[8]

Signs of grub damage

• Grub-damaged turf wilts quickly and yellows, the soil can feel spongy, and the sod may pull up easily because the roots are gone. Penn State adds that heavily damaged sod can be rolled back like a piece of carpet.^[2][6]
• Skunks, raccoons and armadillos digging for grubs can cause more damage than the grubs themselves. Penn State and UW-Madison also name crows, moles and turkeys among the animals that feed on grub-infested turf.^[2][6][8]
• Damage is often patchy because grubs concentrate in parts of a lawn, and rainfall or irrigation can hide root loss, so sample several areas instead of judging by the grass alone. With fewer grubs, the lawn may just look thin.^[2]
• In Pennsylvania, dead or dying patches show up mostly in spring (April and May) and in late summer and fall (September and October).^[6]
• After sampling, water the spots you dug so they don't dry out and die.^[6]

Which grub is it? Reading the raster

• The raster is a set of hairs, spines and bare spaces on the underside of the last abdominal segment, in front of the anus. Lay the grub on its back, rinse that area with water, and use a 10X hand lens.^[6][2]
• Japanese beetle grubs have a distinct V-shaped raster. Masked chafer grubs have a random pattern; Clemson counts 25 to 30 coarse, hooked spines around the anal opening on the southern masked chafer.^[2][6]
• May and June beetle grubs have two lengthwise rows of spines with stouter, more randomly arranged spines around them. Green June beetle grubs have two faint rows surrounded by many short spines, and they lie more or less straight instead of curling up.^[2]
• Full-grown Japanese beetle and northern masked chafer grubs are a little over 1 inch long. Mature green June beetle grubs are about 2 inches long and feed mostly on decaying organic matter rather than roots.^[6][2]
• To send grubs to an extension office for identification, Clemson says to drop them into water that has just boiled and been taken off the heat, leave them for three or four minutes, dry them on a paper towel, and store them in rubbing alcohol. Grubs not killed this way turn black and are much harder to identify.^[2]

How many is too many, by species

Clemson's general rule is that healthy, unstressed turf tolerates 5 to 7 grubs per square foot and poorly managed turf shows damage at lower numbers. The species figures below are Clemson's too.^[2]

• Japanese beetle: healthy, unstressed turf can usually tolerate about 10 grubs per square foot, but because skunks, armadillos and raccoons dig for them, 6 to 8 per square foot may be a safer treatment trigger.^[2]
• Southern masked chafer: well-managed turf may tolerate 20 per square foot, while stressed turf shows symptoms at 8 or more. Populations of 40 or more per square foot are fairly common, and damage is worst in late summer and fall, especially in drought and heat.^[2]
• May and June beetles: more than 7 grubs per square foot can strip the roots completely, and the usual threshold is 4 to 5. Aim at the first and second larval stages, which are easier to kill.^[2]
• Green June beetle: the grubs don't eat grass, but their tunneling and the soil piles they push up cause problems above 5 to 7 per square foot. After treatment they come to the surface, within 12 hours according to Clemson, and may need to be removed because they smell as they decay; other species die in the soil.^[2][7]

Treatment at a glance

There are two approaches. Preventive insecticides give long-lasting protection but have to be down before the grubs are a problem; curative ones work for a short time against grubs already feeding. The full treatment guide has products by active ingredient, timing windows and bee protection.^[8][7][9]

• Small, young grubs are easiest to control; based on when adult beetles are active, that's usually late June to early July. NC State notes that curative treatments in late summer or fall usually work better than spring ones because the grubs are small then; UMass says that once grubs are full-size, often by mid-September, curative treatments seldom cut numbers by more than 50%.^[2][7][9]
• Preventive products (imidacloprid, chlorantraniliprole, clothianidin) go down in spring, April through May, according to Clemson; curative contact products such as trichlorfon go down in July and August. Water granules in right away. Timing advice differs by region: UMass found in New England that early imidacloprid may not last long enough for grubs active in July and August, and recommends neonicotinoids between mid-June and early August; UW-Madison says to apply preventives around or just before egg-laying.^[2][9][8]
• Water matters. NC State recommends irrigating a day or two before a treatment in dry weather, because grubs move deeper in dry soil, and watering most grub insecticides in afterward; carbaryl used for green June beetles is the exception and shouldn't be watered in.^[7][2]
• Biological options: milky spore disease, the most widely used biological grub control, gives variable results; beneficial nematodes work best on small grubs; Bt products for grubs have shown only marginal control. Others are less hopeful: UW-Madison says milky spore hasn't been found effective in recent university research, and Penn State calls results with insect-parasitic nematodes inconsistent.^[2][8][6]
• Keeping the lawn vigorous with proper watering, fertilizing and mowing helps it tolerate grub feeding.^[8][2]

Not grubs? Chinch bugs

• A treatment threshold is about 20 to 25 per square foot, found by kneeling, parting the grass at the edge of a damaged area, or flooding a bottomless can pushed into the soil. In the can test, adults and nymphs float up within five minutes; sample at the edges of the damaged area.^[3]
• The southern chinch bug is a major pest of St. Augustinegrass and also feeds on zoysia, bermuda and centipede grass, injecting a toxin that yellows and kills the grass.^[3]
• Damage starts spotty and shows first where grass is heat-stressed, such as along driveways, sidewalks and roads; lush, heavily fertilized lawns with thick thatch are most at risk.^[3]
• Reduce thatch, water properly and don't over-fertilize; some St. Augustinegrass cultivars, such as Floratam, resist them, though resistance may be breaking down in parts of Florida.^[3]
• In many parts of Florida chinch bugs resist older organophosphate and carbamate insecticides.^[3]

Not grubs? Fall armyworms

• To check, pour 1 to 2 tablespoons of lemon dish soap in 1 to 2 gallons of water over a square yard beside the damage; armyworms come up within 10 minutes.^[4]
• Caterpillars up to 1-1/2 inches long with an inverted Y on the head; they feed in groups early and late in the day and can brown a lawn in hours, usually in late summer.^[4][14]
• Moths drawn to bright lights lay up to 1,000 eggs a night in furry, cream-colored masses on grass blades, fence posts and siding. NC State says the eggs hatch within 2 to 10 days.^[4][14]
• Most feeding happens in the last larval stages (Clemson says over 93% of foliage is eaten after the fourth), so early damage can look like drought.^[4]
• Contact insecticides such as bifenthrin, cyfluthrin, cypermethrin, lambda-cyhalothrin, permethrin or spinosad stop further damage; avoid irrigation for 24 hours after. Check the label first: a January 2026 label for one lambda-cyhalothrin product, for example, no longer allows application to residential lawns.^[4][5]

Not grubs? Sod webworms

• Sod webworm caterpillars grow to about 3/4 inch (NC State gives 5/8 to 1 inch), with dark spots on each segment. They feed mostly at night and leave small brown patches of closely cropped grass that merge into large ones where many larvae are feeding.^[11][10]
• The adults are small, dull, snouted moths that fly over the lawn at dusk and fold their wings tightly against the body at rest.^[11][10]
• To check, Penn State notes that monitoring references often suggest 2 tablespoons of dishwashing liquid in 2 gallons of water sprinkled over 1 square yard; the soapy water irritates the caterpillars and drives them to the surface, and 10 to 15 larvae per square yard may warrant treatment. Pencil-sized holes in the patches can mean birds have been probing for them.^[11]
• Rule out dog urine: it leaves a yellow-to-brown patch with a very green border and no clipped grass blades.^[11]

Not grubs? Mole crickets

• Mole crickets have front legs built for digging, like a mole's. Tawny mole crickets grow to 1-1/2 to 2 inches and the southern mole cricket to 1 to 1-1/2 inches.^[12]
• They tunnel through the soil just under the turf, which can badly damage closely managed grass. The tawny mole cricket feeds almost only on grass roots and shoots; the southern mole cricket mostly eats small soil animals.^[12][13]
• In South Carolina they are mainly a pest of sandy coastal areas. NC State says coarser bermudagrass cultivars are less susceptible than the finer-textured hybrids.^[12][13]
• To check, Clemson suggests mixing 1 to 2 fluid ounces of liquid dish soap in a gallon of water and pouring it over 2 square feet where you've seen tunneling.^[12]

Crayfish chimneys

• Mud 'chimneys' in wet, saturated parts of a lawn in spring are built by burrowing crayfish. The tunnels below can be three or four feet long, running in several directions, and usually end underwater.^[1]
• No chemicals are labeled for crayfish, and home remedies can contaminate water. Improve drainage, replace the lawn in wet spots with native plants that tolerate damp soil, and knock chimneys down before mowing to protect the mower.^[1]

Common questions

Are the white grubs in my garden soil a problem?

Not always. UW-Madison Extension says most white grubs in the Midwest are beneficial scavengers that break down organic matter. The ones to worry about are the turf-root feeders, and you find out by counting grubs per square foot in a lawn that is showing damage.^[8][2]

Do I need to treat for grubs every year?

Not by default. Thresholds depend on the species and the lawn's health, so sample several spots first. Penn State says a set number is hard to fix, but 5 to 10 per square foot is often used for curative treatment.^[6][2]

Why are grubs lying on my driveway in the morning?

Those are probably green June beetle grubs. Older ones come to the surface at night and often end up on pavement or in gutters in the early morning; trapped on hot pavement, they die and smell as they decay.^[2]

Lawn grub and lawn insect guides

Start with the treatment guide if you've counted grubs above threshold, or the identification guide if you haven't found grubs yet.

• How to get rid of grubs in the lawn: thresholds, timing and products
• Lawn insect pests: how to tell which one you have
• How to get rid of Japanese beetles (adults and grubs)
• Beneficial nematodes for grubs
• How to get rid of billbugs (legless lawn grubs)
• How to get rid of chinch bugs
• How to get rid of armyworms and sod webworms
• How to get rid of crane flies in the lawn

Sources

1. Clemson Cooperative Extension Home & Garden Information Center, “Crawfish Chimneys (HGIC, April 13, 2023).” hgic.clemson.edu/factsheet/crawfish-chimneys/ (accessed 2026-11-10)
2. Clemson Cooperative Extension Home & Garden Information Center, “White Grub Management in Turfgrass (HGIC).” hgic.clemson.edu/factsheet/white-grub-management-in-turfgrass/ (accessed 2026-11-10)
3. Clemson Cooperative Extension Home & Garden Information Center, “Chinch Bugs (HGIC 2487).” hgic.clemson.edu/factsheet/chinch-bugs/ (accessed 2026-11-10)
4. Clemson Cooperative Extension Home & Garden Information Center, “Armyworms: Identification, Damage, & Control in Turfgrass (HGIC 2159, updated July 15, 2025).” hgic.clemson.edu/factsheet/armyworms-identification-damage-control-in-turfgrass/ (accessed 2026-11-10)
5. U.S. EPA Pesticide Product Label System, “Demand CS Insecticide label, EPA Reg. No. 100-1066 (EPA-stamped, Jan. 28, 2026).” www3.epa.gov/pesticides/chem_search/ppls/000100-01066-20260128.pdf (accessed 2026-11-10)
6. Penn State Extension, “White Grubs in Home Lawns.” extension.psu.edu/white-grubs-in-home-lawns (accessed 2026-11-10)
7. NC State Extension, “White Grubs in Turf.” content.ces.ncsu.edu/white-grubs-in-turf (accessed 2026-11-10)
8. University of Wisconsin-Madison Extension, Wisconsin Horticulture, “White Grub Control in Turfgrass.” hort.extension.wisc.edu/articles/grub-control-home-lawn/ (accessed 2026-11-10)
9. UMass Amherst Center for Agriculture, Food, and the Environment, Turf Program, “Current Insecticide Approaches for White Grub Control.” www.umass.edu/agriculture-food-environment/turf/fact-sheets/current-insecticide-approaches-for-white-grub-control (accessed 2026-11-10)
10. NC State Extension, “Sod Webworms in Turf.” content.ces.ncsu.edu/sod-webworm-in-turf (accessed 2026-11-10)
11. Penn State Extension, “Sod Webworms in Home Lawns.” extension.psu.edu/sod-webworms-in-home-lawns (accessed 2026-11-10)
12. Clemson Cooperative Extension Home & Garden Information Center, “Mole Cricket Management in Turfgrass (HGIC).” hgic.clemson.edu/factsheet/mole-cricket-management-in-turfgrass/ (accessed 2026-11-10)
13. NC State Extension, “Mole Crickets in Turf (TurfFiles).” content.ces.ncsu.edu/mole-cricket-in-turf (accessed 2026-11-10)
14. NC State Extension, “Fall Armyworms in Turf.” content.ces.ncsu.edu/fall-armyworm-in-turf (accessed 2026-11-10)