How to Spot a Grub Problem: Birds and Animals Digging in Your Lawn

Carrion crow (Corvus corone) foraging on lawn
Nick Upton/2020VISION/Getty Images

Homeowners often struggle with skunks, raccoons, armadillos, robins, moles, or crows devastating a turf lawn by digging it full of holes, never realizing the real cause. These animals do not dig for the fun of it, but because there is something under the ground they are after: grubs.

Many hard-shelled beetles found in the residential landscape may infest the ground with their larvae, which are collectively known as grubs. Japanese beetles and June bugs are some of the common beetles that infest lawns and gardens with ugly white or yellow grubs that eat the roots of garden plants and lawn grasses. In most cases, this is what the small animals and birds are looking for in your lawn. Control the grubs and you control the animals digging up your lawn. 

Animals as Natural Pest Control

Normally, a small amount of feeding in your lawn by birds and small creatures is not a cause for alarm, but a form of natural pest control. There is no reason to leap to methods for attacking the animals and birds themselves, and in many cases, it's best to do nothing. Birds poking holes in your lawn not only rid it of damaging grubs but they also naturally aerate the soil. Some of the many birds that eat lawn grubs include crows, starlings, grosbeaks, magpies, robins, and blue jays. In fact, the more birds in your yard, the better off your garden and lawn will be in terms of pest control.

But large birds and small animals can devastate a lawn if the grub problem is severe, and the answer is not to attack the birds, but to get at the source of the problem leading to the feast.

If you suspect you have a grub problem, take a closer look at your soil. If you have more than five grubs per square foot of lawn, it is considered an infestation and action should be taken. It is not hard to determine if you have grubs. The dead patches of lawn have had their roots severed, and if you pull back on the patch of dead lawn, it will come up easily. If you have a grub problem, you likely will see the ugly white or yellow C-shaped grubs just under the turf layer. 

cockchafer larvae
Alexander Matvienko / Getty Images

Natural Controls for Grubs

Be wary of using synthetic chemical controls for grubs, since these poisons will also affect good garden insects as well as the songbirds that might eat the poisoned grubs. Consider non-chemical approaches:

  • Apply beneficial nematodes to your lawn. Nematodes are microscopic worms. In their larval form, nematode worms eat grubs. Nematodes can be purchased at garden centers or from online retailers. 
  • Spread castor oil granules over your lawn. This will control grubs, and with the grubs gone, so will be the moles, skunks, raccoons, crows, and other creatures eating them. 
  • Apply neem oil to garden plants to discourage Japanese beetles and other hard-shelled beetles. Controlling the beetles themselves will prevent them from reproducing and infesting the lawn with their larvae. 

Using Chemicals

Synthetic chemicals should be a last resort and used only after natural solutions have failed. When purchasing a chemical control, remember that products containing Merit (imidacloprid) or Mach-2 (halofenozide) are for treating the insect eggs in the spring and useless for late summer and early fall applications. When the grubs are already present, it will be necessary to use a chemical like Dylox (trichlorfon) or Sevin (carbaryl).

Water well in the area product application area to get results. It is only effective when it penetrates down beneath the turfgrass root level. Always follow label directions precisely.