Bugs & Grubs In Utah Lawns

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Grub in the lawn


Lawn grubs are the larvae of scarab beetles that dwell under the soil surface, which is where they do most of the damage to your lawn. The adult beetles they will become, as well as other bugs, can also cause damage and make it difficult to maintain healthy turf. Below is some useful information on how to detect a lawn grub infestation.

White Grubs

white grubs in soil

Scarab beetles mate and lay eggs in your soil. The scarab beetles’ larvae are called white grubs, which could be considered the “true” species of lawn grub. These are the white and crescent-shaped larvae that most people picture when they think of grubs. Japanese beetles, June beetles, and masked chafer beetles are some of the most common scarab beetles in the Salt Lake City area, and the white grubs they produce ravage grass roots. Thinning blades of grass, spongy turf, dead patches, and detached roots are all direct results of a white grub infestation.

While these grubs will destroy your lawn, they are harmless to humans, so it is important to examine any areas that show signs of grub damage. The holes they eat through the grass roots make the turf soft and able to peel back easily. Reach out for professional help immediately if you notice any of these signs.


Billbug sitting on a stem

In the larval stage, billbugs are often difficult to differentiate from white grubs. A key difference between these grubs is that billbug larvae do not have legs, and white grubs have 6 legs near their heads. While billbug grubs are also slightly more plump than white grubs, they only measure about half the length of white grubs. The turf damage caused by older larvae is similar to that of a white grub; they feed on the roots and the lower crown area of your grass. Younger billbug grubs eat higher up on the crown of the plant, which will quickly kill the individual grass blades.

When examining your turf, you will notice the ends of the grass blades are chewed and snap right off with ease. Billbug larvae also produce an excrement that is easily identifiable. If you are dealing with a billbug grub invasion, you will likely notice a sawdust-like white powder that they are known to leave in their wake.

Bluegrass Weevils

Weevil sitting on a stem

Both the larval and adult forms of this beetle can cause serious damage to your lawn. This species of beetle gets its name from Kentucky bluegrass, which is a type of turf where this weevil is frequently found. This beetle and its offspring do enjoy the environment created by Kentucky bluegrass, but it can also be found in other popular Utah turfs, such as perennial ryegrass or tall fescue. Their grubs cause yellow spots to form all over your lawn due to them feeding within the stem of the grass. Bluegrass weevil grubs are only between ⅛-¼ the size of white grubs from June beetles.

If you have a bluegrass weevil grub infestation, you will be able to pull up the turf more easily than undamaged turf, but there will be a bit more resistance than you would experience with a white grub infestation. Adult bluegrass weevils chew all around the outside of grass blades and down into the crown. Lawn damage from these weevils typically peaks between July and late summer when the adults of the previous generation and the larvae of the next generation attack your turf all at once.

Chinch Bugs

Box elder bug resting on a leaf

The chinch bug is one of the most prevalent lawn destroyers in the area. The life cycle of the chinch bug does not include a larval stage, but the harm they cause to your lawn is quite similar to the harm caused by a lawn grub or other types of beetles. The youngest form of a chinch bug, known as a nymph, can be identified by its bright red color and white stripe across its body. These tiny bugs can easily be missed and allowed to grow into much more harmful adult bugs.

Chinch bugs have mouthparts that are designed to pierce leaves and grass and suck out the water. The holes they bite in the plants prevent water from being properly distributed, causing the plant to die. Because of the nature of the lawn damage caused by these bugs, watering will never be able to repair the parts of your lawn they destroy.


common lawn grubs

These larvae are typically green or brown in color and have dark heads. The larval, or caterpillar, form of this insect will feed on many different types of plants, including your lawn. They enjoy warm-season turfgrasses, such as Bermudagrass or St. Augustinegrass, but they will also feast on bluegrass, vegetable gardens, grain fields, and anywhere else they can find any form of organic sustenance. The name, “armyworm,” comes from their traveling habits, as large populations will quickly band together to create swarms while they search for food.

When it comes to your lawn, an armyworm invasion can be detected by the “window pane” effect they create on blades of grass. The larva will chew away the top green layer of the grass and leave behind holes, or “windows,” in the grass blades. Adult armyworms are moths, and seeing moths flying in a zigzag pattern across your lawn is a good indicator of armyworms.

Sod Webworms

identifying sod moth

The offspring of these moths are another form of caterpillars that are similar to armyworms. They are usually smaller than armyworms, with a brownish color with dark spots throughout their bodies. Both warm- and cool-season grasses can attract sod webworms. Small and irregular brown patches will begin to form across your lawn if you have a webworm population.

Unlike armyworms, sod webworms’ larvae will only be found feeding at night. During the daytime, webworm larvae can be found burrowed under the soil, which is a quick and easy way to identify the type of larvae you are seeing. Similarly to armyworms, the appearance of moths zipping all over your yard could also mean a sod webworm infestation.

How To Spot Damage

The signs of grub damage are often confused with other harmful factors that can affect your turf, such as lawn diseases, drought stress, compaction, and more. In order to properly treat and remove a grub population from your lawn, you must first know how to identify a grub infestation.

Lawn Turf Pulled Back

Detecting lawn grubs can be as easy as pouring soapy water over the infected area and waiting to see the grubs rise to the surface. Other easy methods of identification include simply raking over the damaged area or getting on your hands and knees to look.

  • Dead Patches - Lawn grubs leave behind irregular, discolored patches on your turf. Areas taken over by an infestation will likely contain thinning or dead patches of grass. Though many factors can cause similar-looking patches, grub-damaged grass will typically have a spongy feel under your feet.
  • Weak/Detached Roots - Grubs get their sustenance from the roots of your lawn, which will quickly become weaker once the grubs eat away at them. If you can reach down and pull up or peel back the damaged grass with little resistance, you are likely dealing with grubs that have weakened your lawn's roots.
  • Presence Of Larger Animals - If grub populations are allowed to grow, you will likely start to see larger animals in your yard that can cause their own damage. Birds, skunks, moles, raccoons, and other critters feed on grubs, and they will destroy your yard as they dig and hunt.

Professional Grub Control In Utah

The technicians at Holmes Lawn & Pest have been providing professional grub control in Salt Lake City since we first opened our doors. We know what signs to look for and how to treat grub infestations, and we will walk you through the best ways to prevent further invasions from ever happening. As part of our fertilization service, we offer grub control at strategic times throughout the season to protect your lawn from anything and everything!

Don’t wait until it’s too late! Call us at (801) 616-5296, and we will be happy to help you with your grub problem in any way we can!

We hope you enoyed this blog about the most common pests in Utah, Boxelder bugs are a very common and very intersting pest here in Utah. Check out this article to learn everything you need to know on this insect.

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