Meet The Grubs That Cause Your Lawn Damage

Spring has sprung, and you’re looking forward to your vibrant, deep green lawn showing itself. There’s only one problem. You’ve started noticing unexplained brown patches in your lawn. The main offender? Lawn damage from grubs. Grubs are the larva of several species of beetle. The most common in the US are white grubs, the larval stage of The European Chafer, and the Japanese Beetle.

Grubs feed on grass underneath the soil at root level. The roots are where your turf sources the water and nutrients it needs to thrive. When the root system is compromised, your grass can’t be healthy. Good lawn-care practices and preventative grub treatment can help get your lawn back on track, but first, let’s look at how you can identify grubs as the cause of your lawn damage.

Related: Pest Control for Your Lawn — A Complete Guide


The Signs of Grub Lawn Damage

Grubs aren’t the only cause of lawn damage. Harsh weather conditions, lawn diseases, or weed infestations can also harm your turf. But, for grubs specifically, there are a few signs you can keep an eye out for:

  1. Moths and beetlesArmyworms are the larval stage of the Owlet Moth. They’re also relatively common grass bugs that cause lawn problems. If you start noticing a lot of beetles and moths flying around your lawn, they’ve probably identified your grass as the perfect nursery for their offspring.
  2. More animal activity — Animals like birds, raccoons, and skunks are a big fan of grubs. If you spot animals frequently digging up or sniffing around your lawn, they’re likely searching for grubs to eat. This causes further damage to your lawn.
  3. Bouncy or soft turf — Because grubs feed on grass roots under the soil, the connection between surface turf and the root base weakens. If your grass feels spongy or bouncy underfoot, it could signify a grub infestation.
  4. Brown patches — Dry, yellow, or brown patches in your grass aren’t always a surefire sign of grubs. They could result from drought or disease, so make sure to look out for the other signs too.

You can’t solve a problem unless you know exactly what it is. Confirm your suspicions by identifying what these grass bugs look like. For more tips on identifying and treating Armyworms, Billbugs and grubs specifically, check out our useful blog.

How to Identify Grubs

Bugs are bugs, right? You could probably tell the difference between a beetle and a moth, but not their specific larvae. Here are some ways to identify common lawn grubs yourself, before you move on to treatment.

The White Grub

white grub

The lawn grub or white grub is instantly recognizable. Off-white in color, about ½ an inch in length, and plump-bodied, these are the larvae of beetles (such as June and Green June beetles). They have brown heads with three pairs of legs. Dig up suspicious-looking brown patches in your grass to find these grass bugs lying in a C-shape. More than five grubs per sq. ft indicate you might have a grub infestation.

Billbug Grubs

billbug grubs
Photo taken by Dean Mosdell


Billbug larvae are similar in appearance to lawn grubs. Like lawn grubs, they’re creamy in color with brown heads and lie in a C-shape when exposed to the air. But, unlike lawn grubs, they have no legs. Ranging from ¼ to ½ an inch long, look out for Billbug feces, light-brown sawdust-like material near the base of your grass.

Japanese Beetle Larvae

japanese beetle larve

Again, the larvae of the Japanese beetle are, in essence, another example of white grubs. Comparatively, their legs are easily visible, and their heads are light, tanned brown. Size-wise, they’re about ⅛ of an inch to 1 inch long. Distinguish these pesky pests from their hairy spines.

Masked Chafer Grubs

masked chafer grubs

The Masked Chafers’ larvae are white, and up to an inch in length. The grubs are recognizable from their dark, translucent dorsal stripes on an off-white body. On the underside of the far end of their abdomen, they have a characteristic scattering of bristles. May or June beetles have two parallel lines of bristles. They’re similar in appearance to the Black Turfgrass Ataenius Beetle larvae but are larger — with a constriction at the forward end of the abdomen.

The Grub Life-Cycle

Understanding when grubs are most likely found in your lawn helps you know when to target them most effectively. Many scarab beetles (such as the Japanese beetle) have a one-year life cycle. In contrast, June beetles have a three-year life cycle. Early midsummer is when adults tend to mate and lay eggs over the course of a couple of weeks.

Egg hatching conditions must be right, dependending on soil moisture and temperature. Mostly, beetle/moth eggs will hatch approximately two weeks after being laid. This occurs in mid-to-late summer. Once they’ve hatched, it’s feeding time. Brown patches start forming in the fall or reveal themselves in the spring after winter. The best time to kill grass bugs is while they’re still young and vulnerable. Apply your chosen pesticide in the mid-to-late summer and early fall for the best results. Consider preventative pesticides if you find grubs are a recurring problem.

Use Acelepryn to Control Grubs

Acelepryn G and Acelepryn SC

Our recommendation for an effective pesticide to treat lawn grub damage is Acelepryn. Acelepryn will target most lawn grubs, Billbugs, and more. Moreover, it won’t eliminate helpful pollinators and insects like bees and earthworms.

One application of Acelepryn will provide season-long protection for warm and cool-season grasses. Containing the active ingredient chlorantraniliprole, it’s safe for people and animals with a limited environmental impact. You can get Acelepryn in both liquid (Acelepryn SC) and granular form, but the granular form (Acelepryn G) is much easier to apply. Treat your lawn with Acelepryn at a rate of 1.8 lbs per 1,000 sq. ft. A single 25 oz bag can cover lawns between 11,000 sq. ft to 21,000 sq. ft.

For application tips, check the product label and watch our helpful YouTube video on keeping your lawn grub-free with Acelepryn.

Keeping Your Lawn Grass Bug Free

Applying pesticides isn't the only thing you can do to prevent grub damage in your lawn. Be vigilant about nearby lawns where your neighbors might themselves have grub problems. Beetles emerging into adulthood will see your lawn as a new place to lay eggs. Grubs enjoy moisture, particularly constantly moist soil. Don’t overwater your lawn, and try to keep it to an inch once a week — weather dependent.

To fix the appearance of your lawn, make sure to repair brown dead patches in your lawn by reseeding the areas affected. Good luck on your pest-free journey, and for a more comprehensive understanding of lawn care, read our Step-By-Step Guide for Getting a Golf Course Lawn.

Golf Course Lawn Store can help you on your way to achieving a Golf Course Lawn. Become the envy of your neighborhood and browse our full range of products today.