Grubs in Lawn: Signs, Dig Test, Thresholds by Species, When to Treat

Key takeaways

• Most turf tolerates up to 5 grubs per sq ft without visible damage, and 20 per sq ft may not show damage in healthy turf (Purdue E-271, June 2023). Cornell reports that insecticide was needed only 20 percent of the time on upstate New York lawns and fairways (Cornell IPM).
• Thresholds depend on the species, which you identify from the spine pattern under the tail: 3 to 4 May/June beetle grubs per sq ft, 5 to 8 European chafer, 8 to 10 Japanese beetle and 18 to 20 Asiatic garden beetle (Cornell IPM threshold table).
• Purdue calls early to mid-July almost always the optimum time for a preventive product (Purdue E-271); curative products work best from mid-August to early September, while grubs are still small (Rutgers FS1009).
• Scotts GrubEx1 is chlorantraniliprole (EPA Reg. No. 538-306), applied April to early August at 2.87 lb per 1,000 sq ft and watered in with about 1 inch (EPA label). Imidacloprid and thiamethoxam are ineffective against Asiatic garden beetle grubs (Rutgers).
• GardenTech’s Sevin Insect Killer Lawn Granules are bifenthrin plus zeta-cypermethrin, not carbaryl (GardenTech SDS, EPA Reg. No. 279-3346-71004); the carbaryl Sevin grub granule (432-1212) was cancelled in February 2024, and UNH Extension, citing Michigan State research, says pyrethroid-only products do not control grubs (2019 article).

What are grubs in a lawn?

Lawn grubs are the C-shaped, cream-white larvae of scarab beetles. They have a tan to chestnut head, three pairs of legs and a darker rear end, and they live in the top few inches of soil, where they chew grass roots. Purdue lists the Japanese beetle, two masked chafers, European chafer, Asiatic garden beetle, Oriental beetle, green June beetle, May/June beetles and black turfgrass ataenius as the turf species (Purdue E-271).

Fact	Figure	Source
Mature grub length	About 3/4 inch (Asiatic garden beetle) to about 1 inch (Japanese beetle, Oriental beetle, northern masked chafer) to 2 inches (green June beetle)	Rutgers FS1009
Where they feed	Mostly within 2 inches below the thatch	Rutgers FS1009
Overwintering depth	6 to 18 inches	UMD Extension
Egg hatch	About 10 days after laying (UMD); about 14 days for Japanese beetle (Penn State)	UMD; Penn State
Density most turf tolerates	Up to 5 per sq ft; under 5 rarely needs treatment	Purdue E-271
How often treatment was needed	20 percent of the time on upstate New York lawns and fairways	Cornell IPM
Best preventive timing	Early to mid-July in Indiana and nearby states	Purdue E-271
Best curative timing	Mid-August to early September, while grubs are small	Rutgers FS1009
Typical kill from a good curative treatment	75 to 90 percent	Rutgers FS1009
Thatch that blocks insecticide	More than 1/2 inch	Rutgers FS1009

Most of them are annual: adults fly and lay eggs in early to mid-summer, the grubs feed from late July into fall, move 6 to 18 inches down for winter and come back up for several weeks in spring before pupating (University of Maryland Extension). May/June beetles need 2 to 3 years per generation and do their worst damage in the second year (Purdue).

What are the signs of grubs in a lawn?

The signs of grubs in a lawn are wilting, discolored patches that do not green up after watering, turf that feels spongy and peels back like carpet because the roots are gone, and animals tearing up the sod. Purdue notes that wilting turf may take on a blue or purple cast before it collapses into dead patches (Purdue E-271). None of these signs proves grubs on its own.

Damage shows in two windows: late summer to fall, when growing grubs meet heat and dry soil, and April to May, when they feed again before pupating (Penn State Extension). Rutgers puts the fastest losses from late August through mid-October (Rutgers FS1009). Kentucky bluegrass, perennial ryegrass and creeping red fescue are the most susceptible lawns; Maryland Extension says tall fescue, zoysia and bermudagrass rarely show noticeable damage (UMD Extension). Rutgers rates tall fescue the most grub-tolerant cool-season grass and perennial ryegrass the least (Rutgers FS1009); mowing heights and seeding rates for the tolerant option are in our tall fescue guide.

Sign	Points to grubs when	Also caused by	Source
Brown or wilted patches	Patches do not respond to irrigation and grow and merge	Drought, disease, shade, compaction	Purdue; UNH
Sod peels back like carpet	Roots are chewed off and C-shaped grubs lie under the mat	Root disease (no grubs found in the dig)	Cornell; Penn State
Spongy feel underfoot	Soil under the sod is loose from tunneling	Thatch	Rutgers
Skunks, raccoons, crows, armadillos or turkeys digging	A dig confirms grubs in the same spot	Earthworms and other insects these animals also eat	Purdue; UNH
Small soil mounds with finger-wide holes	Green June beetle grubs; mounds show after heavy rain	Earthworm castings (pencil-thin holes)	UMD
Brown patches in June to July with broken stems	Not grubs: stems pull away at the crown in a tug test	Bluegrass billbug larvae	UW-Madison, Feb. 2026
Beetles at porch lights or on roses	Not a predictor of grub damage	Normal beetle flight	Purdue

How do you check a lawn for grubs?

You check a lawn for grubs by digging: cut a 1 sq ft flap of sod 2 to 4 inches deep at several spots, peel it back and count the grubs in the thatch and top 2 to 3 inches of soil. Cornell notes that salt or soapy-water drenches, which flush caterpillars to the surface, do not work on white grubs (Cornell IPM). Dig in August, when grubs are near the surface and still small.

1. Pick the date. Begin sampling in August (Northeastern IPM Center); Cornell gives early August for southeastern New York and mid-August upstate (Cornell).
2. Pick the spots. Sample the edges of thin or brown areas, sunny spots and places with a history of damage; Rutgers spaces samples 6 to 10 ft apart on lawns because grubs cluster in patches (Rutgers FS1009).
3. Cut three sides of a 12 by 12 inch square with a flat spade, 2 to 4 inches deep (Penn State), and fold the sod back like a hinge (NE IPM).
4. Break up the soil and thatch and count every grub. A 10x hand lens shows the spine pattern under the tail that tells you the species (UMD).
5. Using a golf-course cup cutter or bulb planter instead? A 4.25-inch core is about 1/10 sq ft, so multiply the average grubs per core by 10 (Northeastern IPM Center).
6. Fold the sod back, press it down and water it so the flap does not dry out (Penn State).
7. Average the counts, compare them with the threshold for the species you found, and mark which spots are over it. Treat those spots, not the whole lawn.

Worked example: the table below averages eight 4.25-inch cup-cutter cores from a hypothetical 5,000 sq ft front lawn. The arithmetic is the method; the counts are illustrative, not field data.

Step	Input	Result
Grubs found in 8 cores	0, 1, 0, 2, 1, 0, 1, 3	8 grubs
Average per core	8 grubs / 8 cores	1.0 per core
Convert to per sq ft (core = about 0.1 sq ft)	1.0 x 10	About 10 per sq ft
Species from raster	V-shaped spine row	Japanese beetle
Cornell threshold for that species	8 to 10 per sq ft	At threshold: treat the sampled area
Hot-spot cores (2, 3) vs rest	Cores with 2 and 3 grubs = 20 and 30 per sq ft	Spot-treat around those cores first

Which grub is it, and how many per square foot is too many?

The species sets the threshold. Larger grubs do more damage each, so Cornell treats 3 to 4 May/June beetle grubs per sq ft as damaging but tolerates 18 to 20 of the smaller Asiatic garden beetle (Cornell IPM). Identify grubs by the raster, the pattern of spines in front of the anal slit on the underside of the last segment, with a 10x lens (UMD Extension).

Thresholds are guides, not laws. The Northeastern IPM Center sets lower numbers for unirrigated turf and tells managers to raise them 30 percent for irrigated turf (Northeastern IPM Center). Rutgers reports well-kept tall fescue plots carrying 60 grubs per sq ft without damage (Rutgers FS1009).

Species	Raster and anal slit (10x lens)	Mature length	Cornell threshold, grubs per sq ft	NE IPM threshold, unirrigated	Life cycle	Product notes
Japanese beetle	Transverse slit; short V-shaped row of spines pointing to the head	About 1 in	8 to 10	6 to 12	1 year	Milky spore strain works only on this species; nematodes work best on it
Oriental beetle	Transverse slit; two almost parallel rows of spines	About 1 in	8	6 to 12	1 year	Nematodes less effective
European chafer	Branched (Y) slit; two rows that spread apart like an opening zipper	About 3/4 in or more	5 to 8	4 to 6	1 year	Damages at lower densities; imidacloprid somewhat less effective
Asiatic garden beetle	Branched slit; distinct semicircle of spines in front of it	About 3/4 in	18 to 20	10 to 20	1 year	Imidacloprid and thiamethoxam ineffective
Northern masked chafer	Transverse slit; scattered spines, no pattern	About 1 in	8 to 12	Not listed	1 year	Imidacloprid somewhat less effective
May/June beetles (Phyllophaga)	Two parallel rows, like a closed zipper	1 in or more	3 to 4	3 to 5	2 to 3 years	Hardest grub to control (UW-Madison)
Green June beetle	Transverse slit; two compact parallel rows; crawls on its back	About 2 in	5	Not listed	1 year	Makes soil mounds; damage at low densities
Black turfgrass ataenius	Small grub of golf turf	Small	30 to 50	Not listed	2 generations a year	Not known to damage home lawns (Purdue)

1. May/June beetle3
2. European chafer5
3. Green June beetle5
4. Oriental beetle8
5. Japanese beetle8
6. Northern masked chafer8
7. Asiatic garden beetle18

Source: Cornell University NYS IPM Program, white grub treatment threshold table Single-value thresholds (green June beetle 5, Oriental beetle 8) are shown as equal low and high ends. Black turfgrass ataenius (30 to 50, golf turf) omitted. Values are in the species table above.

Show the numbers

	Threshold, low end	Threshold, high end
May/June beetle	3	4
European chafer	5	8
Green June beetle	5	5
Oriental beetle	8	8
Japanese beetle	8	10
Northern masked chafer	8	12
Asiatic garden beetle	18	20

Two cautions. Mixed populations are common, so look at several grubs from each spot (Purdue). Japanese beetle traps do not reduce the grubs in your soil and can pull more foliage-feeding adults into the yard (NC State TurfFiles); UW-Madison’s 2026 training slides say not to use them (UW-Madison).

When should you treat grubs in a lawn?

Treat grubs in one of two windows. Preventive products go down before or at egg hatch, usually June to mid-July, and Purdue says early to mid-July is almost always optimum (Purdue E-271). Curative products go down after a dig finds grubs over threshold, ideally mid-August to early September while the grubs are small (Rutgers FS1009). Spring treatments rarely pay.

Rutgers calls late-April-to-May applications the least effective and rarely justified, because the grass can outgrow most spring populations (Rutgers). NC State’s tall fescue calendar says spring curative applications are not effective (NC State AG-367). Cornell says grubs found in October are too late to treat (Cornell).

Month	What the grubs are doing (annual species)	What to do	Source
January to March	Inactive, 6 to 18 inches deep	Nothing	UMD
April to May	Back in the root zone feeding 4 to 6 weeks, then pupating 2 to 8 inches deep	Repair and reseed; skip curative products	Rutgers
June to July	Adults emerge, mate and lay eggs 1 to 4 inches deep	Preventive window; early to mid-July is the Purdue optimum	Purdue; Rutgers
Late July to August	Eggs hatch; small grubs start on roots	Dig to sample in August	NE IPM; Cornell
Mid-August to mid-September	Second and third instars feed near the surface	Curative window, spot-treat over threshold	Rutgers; Penn State
Late September to October	Large grubs; damage and animal digging peak	Trichlorfon or nematodes only; otherwise repair	Cornell
November to December	Moving down to overwinter	Nothing; plan next July	UMD

Species or region	Preventive window	Curative window	Source
Japanese beetle (Wisconsin)	June to July	August to October	UW-Madison Extension
European chafer (Wisconsin)	Late May to mid-July	August to October	UW-Madison
Northern masked chafer (Wisconsin)	June to July	August to October	UW-Madison
May/June beetle (Wisconsin)	May to early June	July to September	UW-Madison
Japanese beetle and northern masked chafer (central Pennsylvania)	Mid-June to mid-July	August to mid-September	Penn State
Tall fescue lawns (North Carolina)	June, when adults fly	After egg hatch, about 24 hours after a heavy rain	NC State AG-367
St. Augustinegrass (Texas)	June in South Texas, July in North Texas	When grubs are present over 5 to 10 per sq ft	Texas A&M EHT-144

Which grub killers work, and what do their labels require?

Grub killers fall into two groups. Long-residual preventives (chlorantraniliprole, imidacloprid, clothianidin, thiamethoxam) kill young grubs for months; fast curatives (trichlorfon, carbaryl) kill grubs already feeding but last days. UW-Madison puts preventive control at 90 percent or more and curative residual at under 10 days (UW-Madison, 2026). The table compiles the EPA-accepted label for one product per active ingredient.

Active ingredient (class)	Example product, EPA Reg. No.	Label timing for grubs	Lawn rate on label	Watering in	Bee statement on label
Chlorantraniliprole (diamide)	Scotts GrubEx1 (registered as GrubEx III), 538-306	Anytime between April and early August; works best before grubs hatch	2.87 lb per 1,000 sq ft; 1 application a year	About 1 inch	None
Chlorantraniliprole (diamide)	Acelepryn, 100-1489 (professional)	Early April to early September for preventive control	0.18 to 0.37 fl oz per 1,000 sq ft	Irrigate immediately or let rain move it in	None
Imidacloprid (neonicotinoid)	BioAdvanced Season Long Grub Control granules, 92564-16	Once, May through mid-August	2.4 lb per 1,000 sq ft	Water thoroughly within 24 hours	None; bans use on linden and basswood
Imidacloprid (neonicotinoid)	Merit 2F, 101563-60, label shows 432-1312 (professional)	Before egg hatch of the target pest	0.46 to 0.6 fl oz per 1,000 sq ft	Irrigate if no rain within 24 hours	Highly toxic to bees exposed to direct treatment
Clothianidin (neonicotinoid)	Arena 50 WDG, 59639-152 (professional)	Through peak egg hatch; lower rate if applied June 1 to July 15	0.14 to 0.29 oz per 1,000 sq ft; 0.1 oz June 1 to July 15 for 3 species	Enough irrigation or rain to move it through thatch	Toxic to bees for more than 5 days after treatment
Thiamethoxam (neonicotinoid)	Meridian 25WG, 100-943 (professional)	Up to 45 days before peak flight; best from peak flight to peak egg hatch	3 to 4 oz per 10,000 sq ft	Within 7 days (prevent) or 1 day (control)	Highly toxic to bees
Trichlorfon (organophosphate)	BioAdvanced 24 Hour Grub Killer Plus, 92564-40	When grubs or damage first appear; best July through September	2 lb per 1,000 sq ft; 10 lb bag covers 5,000 sq ft	Water thoroughly within 24 hours	None
Trichlorfon (organophosphate)	Dylox 420 SL, 5481-643, label shows 432-1464 (professional)	Curative; no calendar date on the label	6.9 fl oz per 1,000 sq ft	Irrigate the same day; pre-water if dry	None
Carbaryl (carbamate)	Andersons 8% Granular Carbaryl, 9198-146	When grubs feed near the surface: late March to May or July to early September	2.4 lb per 1,000 sq ft	Must be watered in immediately	Highly toxic to honeybees and other bees
Bifenthrin + zeta-cypermethrin (pyrethroids)	GardenTech Sevin Insect Killer Lawn Granules, 279-3346-71004 (base label now 101563-303)	Late summer and early fall	4 lb per 1,000 sq ft	1/2 inch immediately	None found
Paenibacillus popilliae (milky spore)	Milky Spore Powder, 63191-1	Any season when the ground is not frozen	1 level tsp every 4 ft in rows 4 ft apart; 10 oz per 2,500 sq ft	Water lightly	None; Japanese beetle grubs only

Species matters here too. Rutgers reports that imidacloprid, thiamethoxam and halofenozide are ineffective against Asiatic garden beetle grubs, and that imidacloprid is somewhat weaker on masked chafers, European chafer and green June beetle (Rutgers FS1009). Where those species dominate, chlorantraniliprole for prevention and trichlorfon for rescue match the evidence better.

What several guides say vs what the EPA record shows in 2026

Older extension pages still name products that changed or left the market. Every row below was checked in EPA’s Pesticide Product Label System in October 2026. Penn State, Rutgers and NC State pages remain useful for biology and timing; only the product names need updating.

What several guides say	What the EPA record shows	Source
GrubEx is imidacloprid (Rutgers FS1009)	Current GrubEx1 is chlorantraniliprole (538-306); the imidacloprid GrubEx 2 (538-303) was cancelled Oct. 16, 2024	GrubEx1 label
Sevin is a carbaryl curative (UNH; Rutgers)	The carbaryl Sevin Grub Killer Granules (432-1212) were cancelled Feb. 23, 2024 (EPA PPLS); GardenTech’s Sevin Insect Killer Lawn Granules (279-3346-71004) are bifenthrin plus zeta-cypermethrin, a registration transferred to Envu as 101563-303 in March 2025	GardenTech SDS; 101563-303 label
Halofenozide (MACH 2) is a preventive option (Rutgers)	All MACH 2 registrations are inactive; 62719-473 was cancelled March 17, 2015	EPA PPLS registration record
Pyrethroid-only products control grubs (some product labels list grubs)	UNH, citing Michigan State research, says lambda-cyhalothrin, gamma-cyhalothrin, bifenthrin and similar pyrethroids alone do not work on grubs; Purdue warns that products ineffective on grubs are also sold under the Sevin name	UNH; Purdue E-271, Fig. 13

How do grub killers affect bees?

Neonicotinoid and carbaryl labels carry bee warnings; the chlorantraniliprole and trichlorfon labels in the table carry none. In a University of Kentucky study, bumble bee colonies foraging on flowering white clover sprayed with clothianidin gained weight slowly and produced no new queens, while colonies on chlorantraniliprole-treated clover developed normally (Larson, Redmond and Potter, PLOS ONE, 2013).

The same study found no harm once the treated lawn was mowed to remove the clover blooms present at treatment and new blooms had formed. The practical rule: mow off flowering clover and dandelions before applying any neonicotinoid, and never let granules or spray land on blooming plants, which the Merit, Arena and Meridian labels prohibit while bees are foraging (Merit 2F label). Lawns kept with flowering clover on purpose, as described in our clover lawn guide, are the case where chlorantraniliprole fits best.

Which states restrict neonicotinoid grub products?

As of October 2026, the 12 states below limit neonicotinoids (imidacloprid, clothianidin, thiamethoxam, dinotefuran, acetamiprid) on lawns. New Jersey, Nevada and Maine bar turf use by everyone, and New York’s turf ban on imidacloprid and thiamethoxam starts December 31, 2026. Most of the rest limit sale and use to certified applicators. Chlorantraniliprole, trichlorfon and carbaryl are not neonicotinoids, and none of these laws restricts them.

State	Rule for lawn and turf use	Effective	Source
New York	No outdoor ornamental or turf use by anyone; exceptions for agriculture, structural treatments within 1 ft of a foundation and invasive pests on woody plants	Clothianidin and dinotefuran Dec. 31, 2024; imidacloprid, thiamethoxam and acetamiprid Dec. 31, 2026	N.Y. ECL 33-1301(13)
New Jersey	No outdoor non-agricultural use, homeowner or licensed pro	Oct. 31, 2023	NJDEP Compliance Advisory 2025-07
Nevada	No purchase or use on plants, turf included, except commercial agriculture	Jan. 1, 2024	AB 162 (2023)
Maine	Imidacloprid, clothianidin, dinotefuran and thiamethoxam prohibited for all persons in outdoor residential landscapes, lawns and turf included	Rule adopted Aug. 5, 2021	Maine Board of Pesticides Control
Connecticut	Restricted use (certified applicators only); from 2027 no neonicotinoid use on lawns and turf without a state finding	Restricted since 2018; use ban Oct. 1, 2027	Public Act 25-33, sec. 32
Washington	No use on nonproduction ornamentals, trees and turf except licensed applications, tree injection or agriculture	Jan. 1, 2026	RCW 15.58.485
California	Turf and ornamental products sold only by licensed dealers and used only by certified commercial applicators	Jan. 1, 2025	CDPR notice on AB 363
Maryland	Use limited to certified applicators, farmers and veterinarians; sale only to certified applicators or farmers	Jan. 1, 2018	Md. Code, Agric. 5-2A-02
Massachusetts	Turf, tree, shrub and ornamental products are state restricted use	July 1, 2022	MDAR neonicotinoid FAQ
Vermont	Outdoor-labeled products registered as restricted use (certified applicators only)	In force	6 V.S.A. 918
Colorado	Only licensed dealers may sell neonicotinoid products	2023 act; dealer-only sales from 2024	SB23-266
Minnesota	No statewide ban; cities of the first class may ban pollinator-lethal pesticides	2023 law	Minn. Stat. 18B.09

Product labels add their own geography. The GrubEx1, Acelepryn and BioAdvanced imidacloprid labels prohibit sale and use in Nassau, Suffolk, Kings and Queens counties of New York (GrubEx1 label; Acelepryn label), and Cornell notes that on Long Island imidacloprid may be applied only by a certified applicator (Cornell IPM). Anyone applying grub control for pay needs a state pesticide license; our guide to the pesticide applicator license for lawn care lists the turf category in each state.

Do natural grub treatments work?

Some do, inconsistently. Beneficial nematodes (Heterorhabditis bacteriophora) give good control of Japanese beetle grubs but less of Oriental beetle, Asiatic garden beetle and European chafer (Rutgers FS1009). Milky spore is the weakest bet: Purdue says commercial formulations act only on Japanese beetle grubs and have not proven effective as a stand-alone single application (Purdue E-271).

Method	What one guide says	What other primary sources report	Source
Milky spore	Works best applied late September or early October on soil pH 6 to 7; effects last many years (NC State TurfFiles)	Japanese beetle only (label); not effective in recent university research (UW-Madison); not shown effective in the Northeast (NE IPM); spring soils in northern New England too cold (UNH)	Label; UW; NE IPM; UNH
Beneficial nematodes (H. bacteriophora)	Good on Japanese beetle grubs; weaker on Oriental beetle, Asiatic garden beetle, European chafer	Best on larger grubs as a curative; refrigerate, apply early morning or evening, irrigate immediately, under 50 psi with screens removed	Rutgers; Purdue
Bacillus thuringiensis galleriae (Btg)	35 to 100 percent control, varying by species (Purdue)	70 to 80 percent on young Japanese beetle and masked chafer grubs; some granular trials failed (UMD)	Purdue; UMD
Metarhizium brunneum fungus	40 to 70 percent control from fall applications on older grubs (Purdue)	Up to 50 percent lower grub density in 3-year studies (UMD)	Purdue; UMD
Dish soap or salt drench	Popular online	Does not bring white grubs to the surface; works on caterpillars only	Cornell IPM
Japanese beetle traps	Sold to cut beetle numbers	No real impact on grubs in the soil; can attract adults	NC State
Letting the lawn go dry in July	Kills eggs and young grubs	Works on eggs, but the grass browns until watered; irrigation in July attracts egg-laying females	Penn State; Rutgers

1. Chemical curative, successful treatments (Rutgers)75
2. Btg, all trials (Purdue)35
3. Btg on young grubs (UMD)70
4. Metarhizium, fall applications (Purdue)40

Source: Rutgers FS1009; Purdue E-271 (June 2023); University of Maryland Extension Milky spore and beneficial nematodes are not charted because the sources give no comparable percentage. Ranges are in the table above.

Show the numbers

	Low end	High end
Chemical curative, successful treatments (Rutgers)	75	90
Btg, all trials (Purdue)	35	100
Btg on young grubs (UMD)	70	80
Metarhizium, fall applications (Purdue)	40	70

Nematodes carry no EPA registration number to check: federal rules exempt biological control agents other than microorganisms and viruses from registration (40 CFR 152.20), while milky spore, a bacterium, is registered (EPA Reg. No. 63191-1). For nematodes, buy from a supplier that ships cold and states the species and count, and keep the soil moist for 1 to 2 weeks after application (Rutgers).

How much does grub control cost?

Grub control costs about $4.90 to $6.40 per 1,000 sq ft for one application of a retail granule bought from the maker on Oct. 28, 2026: GrubEx1 $5.95 to $6.40, trichlorfon $4.90 to $5.80 and imidacloprid $5.65 to $5.80. Milky spore runs $9.35 to $14.00 and nematodes $1.82 to $25.00 per 1,000 sq ft, depending on pack size. Bag size moves the price more than brand does.

Product (active ingredient)	Seller and price, Oct. 28, 2026	Coverage	Cost per 1,000 sq ft
Scotts GrubEx1 (chlorantraniliprole)	Scotts, $31.99; $59.49	5,000 sq ft; 10,000 sq ft	$6.40; $5.95
BioAdvanced 24 Hour Grub Killer Plus (trichlorfon)	BioAdvanced, $28.99 for 10 lb; $48.99 for 20 lb	5,000 sq ft; 10,000 sq ft	$5.80; $4.90
BioAdvanced Season Long Grub Control Plus Turf Revitalizer (imidacloprid)	BioAdvanced, $28.99 for 12 lb; $56.49 for 24 lb	5,000 sq ft; 10,000 sq ft	$5.80; $5.65
BioAdvanced Season Long Grub Control Ready-to-Spread (lambda-cyhalothrin, a pyrethroid)	BioAdvanced, $18.49 for 10 lb	5,000 sq ft	$3.70
Acelepryn G (chlorantraniliprole 0.2%, professional)	Intermountain Turf, $107.10; Sunspot Supply, $127.50, 25 lb	10,870 to 21,739 sq ft at the label rate of 1.15 to 2.3 lb per 1,000 sq ft	$4.93 to $11.73
Sevin 2% granules (carbaryl; the Sevin carbaryl grub granule registration, 432-1212, was cancelled in 2024, so this may be older stock)	Paris Farmers Union, $15.99 for 10 lb	4,292 sq ft	$3.73
St. Gabriel Milky Spore Powder (Japanese beetle grubs only)	ARBICO Organics, $34.99 for 10 oz; $93.49 for 40 oz	2,500 sq ft; 10,000 sq ft	$14.00; $9.35 (one-time)
NemaSeek Hb nematodes (H. bacteriophora)	ARBICO Organics, $40.00 for 5 million; $47.25 for 10 million; $79.20 for 50 million	1,600 sq ft; 3,200 sq ft; 1 acre	$25.00; $14.77; $1.82, plus shipping
Professional grub control, municipal bid (product not named)	Middletown, Conn., Bid 2025-019, item 39: $75, $250 and $275 per acre	Per acre	$1.72 to $6.31
Professional organic grub control, same bid	Item 83: $901 and $1,150 per acre	Per acre	$20.68 to $26.40

1. Lambda-cyhalothrin granule3.70
2. Carbaryl granule3.73
3. Trichlorfon (24 Hour Grub Killer Plus)4.90
4. Imidacloprid (Season Long Plus)5.65
5. Chlorantraniliprole (GrubEx1)5.95
6. Chlorantraniliprole (Acelepryn G)4.93
7. Milky spore powder9.35
8. Hb nematodes1.82
9. Pro bid, conventional (Middletown, Conn.)1.72

Source: Manufacturer and retailer list prices checked Oct. 28, 2026; City of Middletown, Conn., Bid 2025-019 tabulation Single-pack products show equal low and high values. Nematode low end is the 1-acre pack. Prices and sellers are in the table above.

Show the numbers

	Low	High
Lambda-cyhalothrin granule	3.70	3.70
Carbaryl granule	3.73	3.73
Trichlorfon (24 Hour Grub Killer Plus)	4.90	5.80
Imidacloprid (Season Long Plus)	5.65	5.80
Chlorantraniliprole (GrubEx1)	5.95	6.40
Chlorantraniliprole (Acelepryn G)	4.93	11.73
Milky spore powder	9.35	14
Hb nematodes	1.82	25
Pro bid, conventional (Middletown, Conn.)	1.72	6.31

Area to treat, in thousands of sq ft: 5 = 5,000 sq ft (x 1,000 sq ft)Product (retail cost per 1,000 sq ft, Oct. 2026)GrubEx1, chlorantraniliprole ($5.95 to $6.40)24 Hour Grub Killer Plus, trichlorfon ($4.90 to $5.80)Season Long Plus, imidacloprid ($5.65 to $5.80)Acelepryn G, chlorantraniliprole ($4.93 to $11.73)Milky spore powder, one-time ($9.35 to $14.00)Hb nematodes ($1.82 to $25.00, plus shipping)How much of that area you treatWhole area (preventive)Half (spots over threshold)A quarter (spots over threshold)

Water to apply at 1/4 inch (gallons)

779

Water to apply at 1 inch, GrubEx1 label (gallons)

3,117

GrubEx1 product at 2.87 lb per 1,000 sq ft (lb)

14.4

Estimated product cost$30 to $30

Cost = area x share treated x cost per 1,000 sq ft from our Oct. 28, 2026 price table. You buy whole bags, so the checkout total can be higher. Water: 1 inch over 1,000 sq ft = 623 gallons. Follow the label on your product.

Worked example: a 5,000 sq ft lawn where an August dig put 1,200 sq ft over threshold. The table compares a whole-lawn preventive next year with spot treatment now, using the label rates and Oct. 28, 2026 prices above.

Option	Area	Product needed at label rate	What you buy	Cost
Spot curative now: trichlorfon	1,200 sq ft	2 lb x 1.2 = 2.4 lb	One 10 lb bag	$28.99 (7.6 lb left; label allows 3 applications a year)
Spot curative now: Hb nematodes	1,200 sq ft	5 million covers 1,600 sq ft	One 5 million pack	$40.00 plus shipping
Whole-lawn preventive next season: GrubEx1	5,000 sq ft	2.87 lb x 5 = 14.35 lb	One 5,000 sq ft bag	$31.99
Water in GrubEx1 at about 1 inch	5,000 sq ft	623.4 gal x 5	About 3,117 gallons	Your water rate
Municipal bid rate, conventional	5,000 sq ft = 0.115 acre	Contractor supplies	Service	$8.61 to $31.57 at $75 to $275 per acre; home-lawn visits add trip minimums

Municipal bid prices understate what a homeowner pays, because they price acres of park turf in one visit. When a lawn company quotes grub control, ask for the active ingredient, whether it is preventive or curative, whether the price covers spot treatment of sampled areas only, and who waters it in. Our commercial lawn care guide shows how the same bid tabulation prices other program steps.

How do you apply grub control so it reaches the grubs?

Grub insecticides only work in the root zone, so the steps that matter are thatch, water and timing. Rutgers advises irrigating about 1/4 inch right after treatment (Rutgers FS1009), UW-Madison says about 1/2 inch (UW-Madison), and the GrubEx1 label says about 1 inch (label). Follow the label on your bag; it is the legal instruction.

1. Confirm the need with a dig and note which spots are over the threshold for your species (Cornell).
2. Measure thatch. If it is over 1/2 inch, dethatch first, because thatch binds the insecticide (Rutgers; UMD). Our dethatching cost guide covers when a power rake is worth paying for.
3. Mow first, and mow off any flowering clover or dandelions if you are using a neonicotinoid or carbaryl (Larson et al., 2013; UNH).
4. For a curative product in dry weather, water the day before so grubs move up toward the surface (NC State; Dylox 420 SL label).
5. Set the spreader to the label rate: for example 2.87 lb per 1,000 sq ft for GrubEx1 or 2 lb per 1,000 sq ft for 24 Hour Grub Killer Plus. Spread granules on dry grass so they sift into the thatch.
6. Water in on the label schedule: within 24 hours for the BioAdvanced products, the same day for Dylox, immediately for carbaryl. Exception: NC State says carbaryl aimed at green June beetles should not be watered in (NC State).
7. Check results after 1 to 2 weeks and no later than 3: treated grubs turn yellow or brown. If the first product failed, switch to a different chemical class (Rutgers).

Product or source	Watering-in instruction	Gallons per 1,000 sq ft
GrubEx1 label	About 1 inch, to activate	About 623
Sevin Insect Killer Lawn Granules label (grubs)	1/2 inch immediately	About 312
UW-Madison Extension	About 1/2 inch after any grub product	About 312
Rutgers FS1009	About 1/4 inch immediately after treatment	About 156
24 Hour Grub Killer Plus label	Water thoroughly within 24 hours	Depth not stated
Dylox 420 SL label	Irrigate the same day; pre-water if dry	Depth not stated

A sprinkler’s output in inches per hour sets the run time for those depths; our lawn watering guide shows the catch-can test for measuring it.

Should you treat, wait or repair?

Treat only when a dig finds grubs at or above the threshold for the species present (3 to 20 per sq ft, depending on species) and the calendar still gives the product a target. Below threshold, or after October, the better spend is on recovery. The table and flowchart below hold the same logic, from the extension thresholds and the label windows above.

If your situation is	Do this	Why (source)
Every sample under 5 grubs per sq ft	Do not treat; mow high and water in late summer	Most turf tolerates up to 5 per sq ft (Purdue)
Japanese beetle, Oriental beetle or masked chafer at 8 or more per sq ft, found mid-August to mid-September	Spot-treat with trichlorfon or carbaryl and water in the same day	Small grubs, short-residual curatives work (Rutgers; Cornell)
European chafer at 5 or more per sq ft	Curative now; next year a chlorantraniliprole preventive	Damages at lower densities (Purdue); imidacloprid weaker (Rutgers)
Asiatic garden beetle at 18 to 20 per sq ft	Avoid imidacloprid and thiamethoxam; use chlorantraniliprole or trichlorfon	Those two neonicotinoids are ineffective on this species (Rutgers)
May/June beetle at 3 or more per sq ft	Curative July to September	Large grubs, 2 to 3 year cycle (UW-Madison; Cornell)
Grub damage last year on the same lawn	One preventive: chlorantraniliprole April to early August, or a neonicotinoid early to mid-July	Labels; Purdue optimum timing (Purdue)
Grubs found in October, or in April to May	Skip insecticide; reseed bare spots and fertilize in fall	Too late or rarely justified (Cornell; Rutgers)
Animals digging but the dig finds few grubs	Do not treat for grubs; repair turf	Animals also eat earthworms (UNH); Milorganite at 0.02 lb per sq ft cut further digging 75 percent or more (Purdue)
Thatch over 1/2 inch	Dethatch before any grub product	Thatch binds the insecticide (Rutgers)
Lawn in Nassau, Suffolk, Kings or Queens County, N.Y.	Do not use GrubEx1, Acelepryn or the BioAdvanced imidacloprid granule	Labels prohibit sale and use there (GrubEx1 label)

1. 1Did a 1 sq ft dig find fewer grubs than the threshold for your species (5 for most)?

   YesDo not treat. Mow high, water in late summer and dig again next August (Purdue, Cornell).

   NoGo to the next question

2. 2Is it October, or April to May?

   YesSkip insecticide. Reseed bare spots, feed in fall, and plan a preventive application for June to July (Cornell, Rutgers).

   NoGo to the next question

3. 3Is it mid-August to mid-September with grubs over threshold?

   YesCurative: spot-treat with trichlorfon or carbaryl at the label rate and water in the same day.

   NoGo to the next question

4. 4Are the grubs Asiatic garden beetle?

   YesUse chlorantraniliprole or trichlorfon; imidacloprid and thiamethoxam are ineffective on this species (Rutgers).

   NoGo to the next question

5. 5Did this lawn have grub damage last year?

   YesPreventive: chlorantraniliprole April to early August, or a neonicotinoid in early to mid-July, mowing off flowering weeds first.

   NoMonitor only: dig in August and decide then.

Source: Purdue E-271, Cornell IPM, Rutgers FS1009, EPA product labels

Recovery is usually possible while the crowns are still green, because grubs chew roots close to the soil surface rather than the shoots (Rutgers). Cornell recommends regular watering, good fertility and reseeding damaged areas, and reports that fall nitrogen speeds recovery from grub damage (Cornell IPM). On cool-season lawns, reseed bare patches from late August to September; our guide on how to overseed a lawn gives seeding rates, and our lawn care schedule places grub work in the rest of the year. More turf problems and grass profiles are collected in our Turf and Trees section.

Decision	Number to use	Source
Treat or not	Species threshold: 3 to 4 (May/June) up to 18 to 20 (Asiatic garden beetle) per sq ft	Cornell
Preventive date	Early to mid-July (neonicotinoids); April to early August (GrubEx1)	Purdue; label
Curative date	Mid-August to early September	Rutgers
Water in	1/4 to 1 inch, per label	GrubEx1; Rutgers

This page is general information, not pesticide advice. The label is the law: read and follow the label on the product you buy, and check your state’s rules before applying any insecticide.