What You Need To Know About Controlling Grubs With Scotts® GrubEx®

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Scotts® GrubEx® (Amazon) is a specialized product designed to eradicate the Japanese beetle larvae wreaking havoc on your lawn from beneath.

These grubs live by gobbling up your grass roots, and this will eventually kill your lawn.

Lawn Grub

Left untreated, grubs can ruin your lawn in a single season.

Luckily, GrubEx is an extremely effective, easy to use tool in the fight against Japanese beetle grubs.

In this article, we provide sound information to help you make the best use of this excellent product.

  • More about Scotts GrubEx at Amazon

How Can You Tell There Are Grubs In Your Lawn?

If the grubs take hold, you won’t have any problem seeing the large swathes of dead, brown grass, but you don’t want to let it get bad.

It’s important to develop a habit of examining your lawn closely and frequently to spot the signs of trouble.

It’s the only way to know exactly when you should apply GrubEx.

Watch for these three signs of grubs:

Brown, Dry Spots

Brown, dry spots: Of course, during the hot summer months or in times of drought, your grass may dry out, wilt and turn brown from lack of water, but if you see this happening during cooler, wetter months, you should suspect grubs or other subterranean pests, such as moles and voles.

Damage In Sunny Areas

Damage in sunny areas: Grubs like to be in areas where the soil is warm.

If you notice the south side of your lawn seems to be showing more signs of damage than other areas, suspect grubs.


Beetles: If you see beetles bumbling about in your grass or flying just above it in the early summer, you know they are laying eggs.

If you don’t have grubs already, you soon will!

What Is The Best Time To Treat For Grubs?

It’s important to follow the instructions on the GrubEx packaging very closely because precision in both timing and application are essential.

Early May, June and July is the best time to apply this product.

Remember the beetles lay eggs in early summer.

The small grubs hatch in the middle of the summer.

GrubEx works as a preventative by preventing eggs from maturing and hatching, so you want to apply it late in the spring and be sure it is present in the soil through mid-summer.

One application can last for about four months.

An annual application is recommended. Learn more about Scotts GrubEx at Amazon

How Quickly Does GrubEx Work?

It’s important to understand this product does not work by killing grubs.

It works by preventing eggs from maturing, so it works as soon as eggs are present.

It’s essential to get it in place before the beetles begin laying eggs.

How Should GrubEx Be Applied?

It’s best to use a rotary or drop spreader to apply the pesticide evenly over the surface of your yard at a rate of 2.87 pounds per 1000 square feet.

  • Follow up by giving your lawn a good watering to activate the product.
  • Water for about half an hour or to a depth of about half an inch.
  • Keep pets and kids off the turf until the water has soaked in completely, and the grass is dry.

Can GrubEx Be Applied In The Fall?

It’s important not to apply the product at the wrong time of year.

For example, if you apply it in the fall, it will no longer be effective in the early spring.

Additionally, you should avoid applying it when heavy rain is expected, as this will naturally wash away and dilute the product.

This could negatively impact its effectiveness.

How Do I Reseed My Lawn After Grub Damage?

If you already have severe grub damage to your lawn, it’s a good idea to remove the grass and either put in new sod or reseed the entire lawn before your first application of Grub Ex.

If you only have small areas of damage, laying sod is preferable to seeding.

Can I Apply GrubEx And Fertilizer At The Same Time?

Apply the two products simultaneously, but it’s better to apply fertilizer when you reseed your lawn or put down new sod and make the application of GrubEx separately.

Do lawn repair and the fertilizing either in the autumn or in the early springtime.

Follow these steps:

  • Use a rake to remove dead grass.
  • For very thick thatch, scrape it off with a spade.
  • Compost or otherwise dispose of the dead grass.
  • Use an aerator to loosen and aerate the soil.
  • Be sure to get the whole area by walking the machine across your lawn, just like a mower.
  • Good aeration will help your subsequent application of GrubEx to soak in better.
  • Choose your grass seed carefully to be sure of matching your existing lawn.
  • Follow packaging instructions to broadcast the right amount of seed to cover your square footage correctly.
  • Broadcast the seed over the damaged areas and rake lightly to incorporate it into the surface of the soil.
  • Toss out straw lightly to help keep the seed in place and protect it against birds.
  • Water deeply, and be sure to keep the soil moist until the grass has sprouted and become established.
  • Gradually back off watering as the grass matures.
  • When it is 6″ inches high, walk on and mow it.
  • Once the grass has matured, you’ll want to apply some fertilizer.
  • If it’s late spring, apply GrubEx at the same time if you wish.
  • Be sure to use straight fertilizer containing no other ingredients.
  • Do this just before a scheduled watering.

Follow packaging instructions to get the right amount of each product.

Use a drop spreader, and be sure to cover the entire lawn.

Remember to water after applying fertilizer and/or GrubEx.

Is Grub Control Necessary Every Year?

Although it is theoretically possible to eradicate all of the Japanese beetle grubs from your lawn one year and not have them come back the next, it’s not very likely.

It just takes one or two Japanese beetles to lay lots of eggs and produce lots of grubs.

GrubEx does not have a repellent effect on the beetles, so your best bet is to make the application of this product part of your annual lawn care routine.

Is GrubEx Safe For Vegetable Gardens?

This product is for lawn care only.

Remember to read and follow packaging instructions closely.

The label is the law.

Use of GrubEx for anything other than lawn care is a violation of federal law.

GrubEx Is The Best Choice For Japanese Beetle Grub Control

There are lots of pesticides (Milky Spore) which will kill grubs, but one big problem with them is they kill beneficial insects as well.

GrubEx insecticide is guaranteed to be safe for beneficial fauna such as earthworms, bees, predatory wasps, and other types of wildlife.

If you follow the instructions to the letter, you should not have to apply the product more than once annually.

Make a habit of an annual, pre-emptive application, and you will never need to worry about Japanese beetle grub damage again.

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