How to Control Grubs in The Lawn

Early summer beetles can leave behind their hungry grubs to feast on your grass in the late summer.

Keep Grubs from Killing Your Grass

If you have problems with beetles, such as Japanese beetles or June beetles, in the early summer and dead patches of grass appear in your lawn in late summer, you could have grubs. Grubs are the larvae of beetles, including the Japanese beetle, chafers, Oriental beetle, and billbug. They are white, C-shaped creatures that feast on the roots of grass and plants as well as other organic matter in the soil.

Signs of Grubs

There are several tell-tale signs that you may have an issue with grubs in your yard:

  • Skunks, raccoons, and birds dig up your yard. These animals love to eat large, mature grubs and will create ruts in your lawn searching for them.
  • Because grubs eat the roots holding the grass in place, the dead patches in your lawn will pull back like pieces of loose carpet.
  • Before the dead patches appear in late summer, your lawn will feel spongy when it's stepped on (like freshly laid sod).

Checking for Grubs

To see if you have a grub problem, peel back a square foot of green grass in several area throughout your lawn. If you see 6 or more grubs in each area, it may be time to treat. Usually, a properly maintained lawn can tolerate more grubs per square foot. A drought-stressed or under-fertilized lawn will grow grub damage sooner and with fewer grubs per square foot.

Grub Lifecycle

Adult beetles emerge from the soil in early summer and feed on plants in your garden before laying their eggs in the soil. Later in the summer, the grubs hatch and immediately begin to feed. The grubs will continue to eat and grow until mid-fall when they move deeper in the soil where they will survive the winter. In the spring when the soil warms up, the large, mature grubs move back up near the soil surface where they transform into the adult that emerge in early summer to repeat the process.

Controlling Grubs

The key to successful grub control is to kill them before or just as they hatch, before they begin to cause damage to your lawn or garden. Preventative grub control products should be applied in spring through early summer before or just as the grubs hatch. Always follow label directions when applying any control product.