How to Get Rid of Lawn Grubs (and Tell if You Really Have Them)

Half the people treating their lawn for grubs don’t have a grub problem. 

They have a drought problem, a fungus problem, or a dog that pees in the same spot. Pesticide goes down anyway, money gets spent, and the brown patches stay brown. 

Before you buy anything, you need to know what you’re actually looking at.

The real test takes about two minutes. 

Cut a one-square-foot flap of turf with a shovel, peel it back like a carpet, and count the white C-shaped larvae in the soil underneath. Five or fewer per square foot is normal, every lawn has some. Six to nine is borderline. Ten or more is a genuine infestation worth treating.

That’s the whole diagnostic. Skip it, and you’re guessing.

What Grub Damage Actually Looks Like

Grubs eat grass roots, so damaged turf pulls up like a loose toupee. 

No resistance, no anchored roots, just a mat of dead grass lifting cleanly off the soil. This is the giveaway that separates grub damage from drought stress, where the grass stays rooted even when it’s crispy.

The other tell is wildlife. 

Skunks, raccoons, crows, and moles tear up lawns hunting grubs. If you wake up to a yard that looks like someone went at it with a garden fork overnight, something is eating well down there. 

Birds working a single patch repeatedly is a softer signal but worth noting.

Damage typically shows up in late summer through fall, when grubs are largest and feeding hardest. A lawn that browned out in July is almost certainly not grubs, it’s heat and water.

Timing Is Everything

Grub control products fall into two categories, and using the wrong one at the wrong time wastes the application entirely.

• Preventive products (chlorantraniliprole, imidacloprid) go down in late spring to early summer, roughly May through early July, in most of the country. They sit in the soil and kill grubs as they hatch from eggs. Apply these in the fall, and you’re months late, the grubs are already large, and the chemistry doesn’t work as well on mature larvae.
  
• Curative products (carbaryl, trichlorfon) kill grubs that are already there and actively feeding. Apply these in late summer or early fall when you’ve confirmed an active infestation. They’re harsher, work fast, and need watering in immediately after application, a quarter to half an inch of water within hours, or they break down on the surface before reaching the soil.

Don’t apply curative products in spring. Grubs come up to feed briefly, then pupate into beetles. You’d be poisoning the lawn to kill insects that are about to leave on their own.

The Biological Options

Beneficial nematodes, specifically Heterorhabditis bacteriophora, are microscopic worms that hunt grubs in the soil. 

They work, but the conditions have to be right: soil temperature above 60°F, moist soil before and after application, and application in the evening or on an overcast day because UV light kills them. 

Buy them from a supplier with refrigerated shipping, not off a shelf where they’ve been sitting at room temperature for six months.

Milky spore is the other commonly recommended biological control. It targets Japanese beetle grubs specifically and does nothing for European chafers, masked chafers, or June beetles. If you don’t know which species you have, milky spore is a coin flip.

What to Actually Do

If your grub count is under ten per square foot and the lawn looks fine, do nothing. Healthy turf tolerates a low grub population without visible damage.

If you have confirmed damage and counted high numbers in summer or early fall, use a curative product, water it in properly, and overseed the dead patches once the grubs are dead. Don’t reseed before treatment, you’ll just feed the next generation.

If you had grub damage last year and want to prevent a repeat, use a preventive product the following spring. One application, timed correctly, handles the whole season.

The Lawn Itself Does Most of the Work

Beetles lay eggs in short, stressed, dry lawns because the soil is warm and accessible. 

Tall grass, mowed at three to four inches, shades the soil and discourages egg-laying. Deep, infrequent watering builds root systems that survive moderate grub feeding without browning. 

A lawn that gets mowed too short and watered five minutes a day is the lawn beetle’s target.

The single best long-term grub strategy is mowing higher and watering deeper, and it costs nothing. Keeping your lawn healthy starts with reducing stress across the whole yard. Aiper’s smart irrigation system can help you achieve precise moisture control, making it easier to maintain deep-root hydration while automating your seasonal watering schedule for a resilient, thriving landscape.