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Recognizing and addressing grub infestations

October 19, 2020

By Josiah Anderson

Lawns face many threats, not the least of which is grubs. The larvae of certain types of insects, including beetles, grubs feed on the roots of grass and plants and can turn even the greenest, most impressive lawns into unsightly eyesores.

Many homeowners spend lots of time tending to their lawns, so the effects of grub infestations can be especially frustrating. Learning to recognize what grub infestations look like and how to address them can help homeowners restore their lawns as quickly as possible.

What do grub infestations look like?

According to the University of Illinois Extension, lawns affected by grub infestations will show wilting and browning of irregularly shaped areas. But grass that is turning brown is not always indicative of a grub infestation, as numerous factors can cause grass to turn brown.

Homeowners who suspect their lawns have been infested with grubs can approach spots where brown grass is meeting green grass and pull up the sod. Grubs appear slimy and C-shaped, and 10 or more within a square foot of sod is a sign that grubs have taken over.

Another potential indicator of grub infestations is holes or dirt channels in the lawn. These might be a byproduct of skunks, moles and raccoons digging up the lawn in search of grubs to eat.

Soft, spongy ground that is easy to pull up may also be indicative of grub infestations.

When are grub infestations likely to occur?

The timing of grub infestations may depend on geography. Homeowners who suspect their lawns have been infested by grubs can consult with lawn care professionals to determine if that’s likely. Some grub infestations discovered in the spring may actually be byproducts of infestations that began in the previous fall.

How can grub infestations be treated?

One way to treat grub infestations is to remove thatch from lawns. Thatch can harbor grubs by shielding them from pesticide applications. Aerating a lawn allows air, water and nutrients to penetrate the soil, fostering stronger roots that promote healthier lawns. Aerating also removes thatch, taking grubs’ shelters away in the process.

Another way to combat grub infestations is to water deeply and infrequently, which encourages strong roots. Grubs prefer moist soil, and beetles are less likely to lay eggs that become grubs in lawns that are watered infrequently and deeply.

Insecticides can be applied to treat grub infestations, but insecticides might be most effective at preventing such infestations rather than treating existing ones. If grub infestations are discovered early, insecticides can prevent the problem from spreading.

Grub infestations can be an unsightly nuisance. But such problems can be solved if recognized and addressed quickly.