How to Get Rid of Grubs (2024)

4 Ways to Get Rid of Grubs

Nearly all lawns have a few grubs, but they rarely cause trouble unless their population soars.

Before treating your lawn for grubs, the first step is to make sure that your brown grass is being caused by grub damage vs. fungus, overwatering, disease, or other pests or challenges. To determine if grubs are the culprit, remove a square foot of sod, about 3 inches deep, from the center of a brown patch. Sift through it and look for milky white C-shaped larvae. The insects can vary in length from ½ inch to 1 inch, depending on the species of beetle they will eventually become.

If you find 10 or more grubs in the sod you removed, it’s time to formulate a treatment plan. We’ve put together the best ways, both natural and chemical, to deter and/or kill grubs.

1. Introduce Nematodes

If you’re looking for a natural way to rid your lawn of grubs, consider introducing beneficial nematodes to your lawn. Nematodes (typically of the Heterorhabditis bacteriophora, or Hb, variety) are microscopic parasites that invade grubs’ bodies, releasing bacteria that multiply and ultimately kill the host grub.

It can take up to 3 years for nematodes to establish a colony large enough to eradicate a large population of grubs, but going this route means you won’t have to treat your lawn with chemicals. If you’re using nematodes to control grubs in your yard, keep in mind the following guidelines:

• Order nematodes from a reputable source; they are living organisms that must be transported with care (usually refrigerated) and applied soon after they arrive.
• Always follow the nematode producer’s instructions for application.
• Know what you’re buying: Certain species of nematode only control certain species of grub.
• Nematodes may need to be applied when the species of grubs they control are active in the soil.
• While the nematodes are getting established, keep the soil moist and don’t let it go dry.
• Apply nematodes on an overcast day, or in the early morning or evening, as exposure to light or heat can kill them.
• To control an infestation, nematodes may need to be applied every 2 weeks until the infestation subsides. If using nematodes preventively, apply 2 to 3 times a season.

2. Apply Milky Spore

Available in powder form at a garden center or at online retailers, Bacillus popilliae spores, sold as milky spore, infect grubs with a fatal disease known as milky disease. As they die, the grubs release yet more spores into the soil, which are then ingested by other grubs. Milky spore is organic and won’t harm your lawn, but it’s deadly to grubs.

Like nematodes, milky spore isn’t a quick fix. It takes a few years to develop enough of the beneficial spores to rid the yard of grubs. But once established in the soil, the “disease” effectively wards off grubs.

There are, however, some caveats. Milky spore is effective only on grubs of the Japanese beetle, which has spread throughout most of the eastern and central states but isn’t yet common in the West. If your brown patches are caused by some other grub, milky spore won’t help. Making things even trickier, it can be tough to tell one grub from another. Hairs on the hind end of the abdomen of a Japanese beetle grub form a distinctive V-shape, but you need a hand lens to see them. As well, milky spore is less effective in colder climates where spring soils aren’t warm enough for the disease to thrive. Finally, recent studies have suggested that milky spore may not be as effective at controlling grubs as initially thought. But if you’re certain you’re dealing with grubs of the Japanese beetle, milky spore can be the way to go.

3. Don’t Fight Drought

Beetle eggs need moisture to survive, so if you have a grub problem, you can try drying out your lawn to make it as inhospitable as possible.

If you experience drought conditions during the summer months, when adult beetles lay their eggs, take advantage of the dry conditions by making the conscious decision not to water your lawn for 3 or 4 weeks to further dry out the soil. The eggs will eventually die, which will reduce next year’s crop of larvae.

Your lawn will dry out, too, but as long as your grass is in good condition, it should spring back to health when you resume watering.

4. Chemical Control

Chemical-based grub control can be very effective, but keep in mind that these chemicals can kill both beneficial insects and grubs. Take care to understand the manufacturer’s instructions for safe use, and be sure to consider the risks that chemical lawn treatments can pose for children and pets.

Generally speaking, chemical treatments fall into two categories: curative and preventive.

• Curatives, which are designed to kill immature larvae, should be applied in late summer or early fall when young grubs are actively feeding on grass roots. Look for a product that contains trichlorfon, such as Dylox. Note that curatives do not affect grubs that have already developed into pupae.
• If you’ve had a grub problem in the past, or if you’ve spotted telltale brown patches in your neighbor’s yard, applying a preventive grub-control product will reduce the risk of your lawn becoming infested. These treatments are typically applied in late spring/early summer. While they will stop the next generation of grubs, they have little effect on any young grubs that are currently chomping away in your grass. Look for preventive products that contain either imidacloprid (such as Merit) or halofenozide (such as Mach 2).

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