• Background Image

Dead Grass? Grub Worms May Be the Issue

Dead Grass? Grub Worms May Be the Issue

If you have dead spots in your beautiful lawn, chances are you want those areas restored to their dark green color as soon as possible. Usually, the culprit is damage caused by lawn grubs and immediate action is required. 

However, dead patches may also be the result of not enough watering, especially in the hot summer. Sometimes sprinklers don’t cover all the areas in a law adequately or you may have a plugged sprinkler head you are not aware of.

To narrow down the culprit, you should measure to see how much water the dead area is getting by putting a small can in the brown area. Turn on the water, which should measure about 1/4 of an inch in the can after 15 minutes of watering.

Check out our Lawn Watering Guide for additional details

If you discover the problem is with your sprinkling system, an application of Revive will restore your lawn to its dark green color. But, if the water from the sprinklers is adequate, then your lawn may have grubs.

What Are Lawn Grubs?

Lawn grubs are larvae that are hatched from eggs laid primarily by billbugs and occasionally by June beetles. They will eat and destroy the root system of the lawn, causing brown spots. If not treated quickly, they can overtake the entire lawn.

Lawn grubs come in different forms: billbug larvae (grub) look like a grain of rice with a tan head. A white grub from the June beetle is bigger and curls up into a distinctive “C” shape. The most common lawn grub in Utah comes from the billbug.

close-up of lawn grub worm

Billbugs and June beetles lay their eggs in the spring. Grub damage begins soon after the grubs hatch and start eating lawn roots, with severe symptoms beginning to appear (large dead areas) around the fourth of July (earlier in warmer areas such as Washington County).

Once the grubs have damaged your lawn, you’ll need to repair it. If it’s a small enough area, you can rake up the dead grass, fertilize and water the damaged area, and your lawn will return. If the damaged area is big enough, though, you’ll need to re-seed or lay new turf to repair your yard.

Getting Rid Of the Little Grubbers

When it comes to these little pests, a lot of people wait until they see the damage caused by the grubs before they apply something to kill them. But the key to getting rid of the grubs is to prevent or treat them.

Preventing Grubs

The best way to control lawn grubs is to prevent them by applying a systemic grub-killing insecticide during the month of May (in most locations in Utah and surrounding states). Bonide Insect & Grub Control or BioAdvanced Complete Insect Killer For Lawns are both excellent choices for grub prevention because they are systemic and can provide season-long grub control.

When the new lawn grubs hatch and emerge from their eggs, their first taste of lawn roots will contain the applied systemic insecticide, which will kill them immediately. The grubs won’t ever become a lawn-destroying menace.

Grub Treatments

If you need to treat them, then you can bring out the big gun: Bayer 24-Hour Grub Control. They will take care of your problem in 24 hours.

A second hatch of grubs is possible in late summer—late August or early September. If you see signs of a resurgence of grubs, simply apply a second application.

All three of these products (Bonide Insect & Grub Control, BioAdvanced Complete Insect Killer, and Bayer 24-Hour Grub Control) are safe for kids and pets. Just apply as directed and water in with a half-inch of water and wait for the lawn to dry.


Let Us Help

Our associates are as passionate about lawn care as you are. Stop by your local IFA Country Store and we'll be happy to answer any questions or help you solve any lawn problem, big or small.

Find an IFA Country Store near you


Originally published July 6, 2016 on www.ksl.com. Edited on May 3, 2019.