Achieving a healthy lawn can be a daunting task if you can’t determine the root of the problem. Grubs, which are a general classification for a wide range of beetles, including Japanese beetles and June beetles, feed on the roots and leaves of the grass and cause many unsightly lawn problems. But finding out if they’re the cause of your lawn woes is half the battle. Here’s how to identify a grub problem in your lawn or garden.
For a surefire way to determine if grubs are eating your grass, dig up a few 2-inch deep, 1-foot around samples of dirt from a dead patch in the lawn. Sift through the dirt and look for C-shaped white grubs. These are the larvae of European chafer beetles, which are common in Michigan.
In Colorado, you may also have a grub problem if you see sawdust-like material present on your grass. This can be a sign of a billbug infestation. Billbugs in the damaging stage are .25 to .5 inches long and are white or cream with a brown head. If you can see eight or more bugs per square foot, you should consider getting a professional grub treatment immediately.
If you’d rather not dig up grass, you can test the likelihood of grubs’ presence by observing the damage to the lawn. Grubs can cause the grass to wilt and turn brown — generally in patches — causing an uneven, unhealthy appearance. Grubs are also known to cause your grass to become spongy, which allows you to roll back the sod like carpet to get a better look at the soil.
Grubs are also a desirable source of food for many animals, including birds, skunks and raccoons, so be sure to keep an eye out for any holes that appear to have been dug up by small animals. Because other factors, like dry and hot weather, can also contribute to brown patches in the grass, digging up the soil is the best way to decide if grubs are the culprit.