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Dead grass? Utah grubs may be to blame

Dead grass? Utah grubs may be to blame

(Hall | Stewart Lawn + Landscape)

This archived news story is available only for your personal, non-commercial use. Information in the story may be outdated or superseded by additional information. Reading or replaying the story in its archived form does not constitute a republication of the story.

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 lawn 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. 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.


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.


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). Hi Yield Grub Free Zone, Amdro Quick Kill and Bayer Season Long Grub Control are 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.


If you need to treat them, then you can bring out the big guns: Bayer 24-Hour Grub Control or Amdro Quick Kill. 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 resurgence of grubs, simply apply a second application.)

All four of these products (Hi Yield Grub Free Zone, Amdro Quick Kill, Bayer Season Long Grub Control 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.

Intermountain Farmers


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