When to Apply Grub Control | Best Time to Treat Your Lawn

Do you have a problem with grubs? These pests can destroy your lawn, so you need to know how to get rid of grubs in your yard.

You may have questions about how and when to apply grub control. The following information can help you understand the best time to treat your lawn.

What Are Grubs?

Lawn grubs are beetle larvae. Some of the most well-known species are the Japanese Beetle and June Bug, which occur across North America. They typically hatch during the spring and summer.

There are slight variations depending on the kind of beetle, but most larvae are short and thick. They’re white or grayish and have brown heads.

Their length ranges from less than an inch to 2 inches, and they typically curl up in a “C” shape when disturbed.

When to Apply Grub Control | Best Time to Treat Your Lawn

Beetles usually lay eggs in the soil during the spring. When the larvae hatch, they start growing and pass through three developmental stages.

They can munch on grass roots, and lawn damage usually shows up in late summer.

How to Identify a Grub Infestation

Grubs aren’t just pests. They’re decomposers that play a critical role in the ecosystem. Their job is to dethatch your lawn, eating the accumulated organic matter in the top inch of soil.

However, while they consume dead grass and leaves, they also eat the roots of turfgrass. Because of this, grubs can seriously damage your lawn if there are too many of them.

In this video, jarid will explain how to determine the difference between fungus on a lawn and grub damage:

Patches of Discolored Grass

The first sign of a grub infestation may be a patch of grass turning yellow. After that, you may notice it dries up completely.

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You can test the straw-colored grass by pulling at it. If it comes out easily, it likely means grubs have chewed through the roots.

If it’s difficult to remove from the soil, the problem is probably another, such as drought stress or damage from dog urine.

Small Holes in the Yard

Animals like raccoons, skunks, and birds feed on grubs. To get to the larvae, they dig in your yard, leaving holes.

Skunks dig shallow holes about the size of their nose. You’ll see a ring of loosened thatch or soil around each cavity. Raccoons tend to flip over pieces of sod using their front paws.

When to Apply Grub Control | Best Time to Treat Your Lawn

Soil Test

You can perform a simple test to determine whether you need to treat your lawn for grubs. Remove a small portion of grass or sod where it’s dry and brown.

You want it to be about 1 square foot in area and 2 to 3 inches deep.

You’ll likely find some grubs under the piece you remove. If you see 5 or fewer, you don’t need to worry, though it may be enough for raccoons and skunks to start poking around.

If there are 5 to 10, you may want to treat your lawn, especially if the grass seems unhealthy. Over 10 larvae per square foot are a sign you need to take action immediately.

Organic Treatment and Prevention Options

Homeowners concerned about the environment may want to try a natural option before resorting to chemicals. These treatments are safe for beneficial insects. However, they may take years to end your grub problem.

Milky Spore

If your problem is with Japanese Beetle grubs, this organic solution may work for you. Milky spore is a bacterium that’s lethal to this species. Sprinkle the powder on the affected area to eliminate the larvae.

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Beneficial Nematodes

These microscopic parasites are worms that occur in nature. They enter the grub’s body and release bacteria that eventually kill the host.

While they’re effective, the process can take up to 3 years to end your problem.

When to Apply Grub Control | Best Time to Treat Your Lawn

You need to follow these guidelines for maximum effectiveness:

  • Use the worms soon after you purchase them so they don’t die.
  • Water the grass thoroughly before and after applying the parasites.
  • Apply the treatment during the afternoon.

This solution is best for small areas of infestation. If you feel insecure applying beneficial nematodes on your own, you can pay an experienced organic lawn care professional to do it for you. They’ll know precisely how and when to use the worms to eliminate the grubs.

Dry Out the Lawn

If you always water your lawn, this technique may sound risky. However, grub eggs can only hatch under the right growing conditions, including significant amounts of moisture.

Stop watering your lawn for 3 weeks to a month. By drying out the soil, you also stop the larvae from hatching. Most types of grass bounce back and turn green again after a dry spell.

Choose Grass Carefully

Tall fescue grasses are more resistant to grubs than other kinds. They can tolerate between 12 and 14 larvae per square foot before they show damage.

When to Apply Grub Control | Best Time to Treat Your Lawn

On the other hand, varieties like perennial ryegrass and Kentucky bluegrass may suffer when there are only 8 to 10 per square foot.

Keep Your Lawn Healthy

The thicker and taller your grass, the less likely it is that beetles will lay eggs in it.

You can help your lawn grow healthy by applying nitrogen once annually in late October or early November. During the rest of the year, mow high and avoid overwatering.

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Chemical Treatments

Chemical solutions take effect more quickly than organic treatments. There are 2 types: curative and preventive.

Curative treatments eliminate grubs that already exist. The most common products use the ingredients trichlorfon and carbaryl.

Water the grass before and after applying the pesticide to ensure the soil absorbs it, and follow any other instructions on the package.

Preventive treatments help keep grubs from multiplying in the future. Products typically contain the ingredients thiamethoxam, imidacloprid, and clothianidin. You may also see the brand names Mach 2 and Merit.

If you choose to apply these products yourself, follow the directions carefully. Chemical pesticides are harmful to humans and other living creatures.

You can reduce the harm to beneficial pollinators by mowing your lawn just before applying the pesticide. In this way, there won’t be any weed flower heads to attract them to the poisoned area.

When to Apply Grub Control | Best Time to Treat Your Lawn

Timing Your Anti-Grub Treatments

In general, late spring and early summer are the best times to treat your lawn for grubs. Specific chemical treatments may affect the larva at different life stages.

For this reason, you need to follow the instructions exactly as they appear on the package for maximum effectiveness.

Preventive treatments work best if used in June or July. Brown patches typically appear in August. At this point, it’s too late to keep an infestation from occurring.

In Summary

Grubs are beetle larvae that serve as dethatchers. They also munch on the roots of your grass. If they multiply out of control, they can cause severe damage to your lawn.

Multiple organic and chemical solutions can help control the grub population. The ideal period for application varies slightly depending on the product.

However, late spring and early summer are typically the best time for preventing damage later in the year.

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Jill Sandy

I am a sustainable focus gardener. I love decorating my home backyard with beautiful landscape design and creative garden care techniques I develop myself.