Grubs, also called grubworms or white grubs, are the larvae of May or June beetles. They feed on the roots of lawns, flowers and vegetables and can cause severe lawn damage if there is a heavy infestation. They live underground and for this reason they are often overlooked as a cause of lawn damage. Look for these signs if you think you may have grubs in your yard.
A dying lawn is one of the most common signs of grubs. The grass will gradually thin and turn yellow. Eventually it dies, leaving brown patches throughout the yard. The patches that signify a grub problem are usually irregularly shaped and not the circular shape associated with fungal diseases like brown patch.
Grubs damage grass by eating its roots. This causes the grass to die and the roots to become detached from the grass. The brown patches in lawns that are infested with grubs can often be lifted in one piece like carpet because they no longer have roots to hold them down.
If you suspect grubs may be causing problems in your yard, dig up a few square-foot areas in your yard and look for them. If you find white, C-shaped wormlike creatures with tan or brown heads and three sets of legs, you have white grubs. Treat your lawn with an insecticide for grubworm control if you find five or more in a square-foot area.
White grubs can attract other animals such as wasps, armadillos, moles, raccoons and birds to your lawn, too. However, these animals are not a sure sign of a grubworm infestation. They may be interested in other organisms like earthworms. If you do find an increase in other kinds of pests adding to the damage in your yard, you may want to inspect the areas for grubs to be sure.