When to Treat for Grubs? – The Answer Is Here

Grubs, also known as Japanese beetles, are one of the most common insects that destroy the lawn by feeding on the grassroots . If you discover that your lawn is getting damaged due to the white grubs, then you have to take immediate action to control them.

Grubs are small in size and live in the soil, so detecting will not be easy. You need to treat and eliminate the grubs before they lay eggs and increase in number.

Getting rid of the insects from your lawn will be easier if you treat them at the right time. In this article, we will discuss when to treat for grubs to eliminate them from the lawn.

When to Check for Grubs?

If grubs are present in your lawn, then you will notice some signs of grub damage at first. The most common signs are:

Brown patches

The grubs eat the root of the grass, and therefore, the grass will begin to yellow and thin. You will see irregular-shaped brown patches at different parts of the lawn. It is one of the common signs, which indicates that the grubs are damaging your lawn.

Increased activity of animals

If grubs are present in your lawn, you will see an increasing number of birds, moles, skunks, and raccoons in your lawn. They feed on these white grubs,so they will damage your lawn by making innumerable holes to search for their food.

Spongy Grass

Other than the above signs, you will see that the grass of the lawn has become spongy, plus, the turf will roll up like a carpet when you lift it. These signs indicate that grubs are damaging your lawn .

If you detect these signs on your lawn, then you need to check for grubs immediately. To do that, first, you need to lift the turf and dig up the soil with a spade. Dig up to 2 to 4 inches to check whether there are grubs underneath.

If there are less than 5 grubs per square foot, then you don’t need to take any preventive measures as it is non-risky.

But if you find more than 5 grubs per square foot, then there are chances that it will increase in number and will cause further damage to your beautiful lawn. So you have to eliminate them at the right time before they increase in number.

When to Treat for Lawn Grubs?

You can start treating the grubs once you confirm that there are grubs in your lawn. The best way to kill them is by purchasing a grub killer insecticide. Different effective grub killer products come in two forms: Liquid and granular.

Purchase the one according to your necessity and start applying it on the affected areas of your lawn to kill both the adult and young grubs. Grubs become active and start hatching from late June through mid-August, so it is the best time to apply the insecticides in your lawn to kill the grubs.

If you are going to apply it by yourself, then make sure to follow the instructions that are specified on the label of the product carefully.

Next, water the affected area after applying the product so that it gets deep into the soil and kills the grubs. You can also apply them during rainfall to achieve the best results.

The above treatment is just a curative one and is effective only for a short time. So, after getting rid of grubs by using insecticides, you can apply the preventive treatment to block the grubs from coming back to your lawn again.

Frequently Asked Questions

  1. Can you treat for grubs in the fall?

Yes. You can treat for grubs in early fall as during that period the hatched grubs will be smaller in size,plus, they come closer to the soil’s surface, so killing them will be easy. Treating adult grubs are more difficult than the younger ones, so you need to get rid of them when they are in the larvae stage.

  1. How to treat grubs naturally?

There are different ways to treat the grubs naturally. You can make a spray with beneficial nematodes and use it on the brown patches of the lawn. Beneficial nematodes are roundworms that multiply over time and kill the grubs without damaging your lawn.

Or you can use milky spore to kill the grubs, but it takes time to be effective. Some people also found the mixture of neem oil and water quite helpful for treating the grubs. Moreover, you can also use garlic to get rid of the grubs.

  1. When is best time to treat for grubs?

The right time to treat grubs is in late summer to early fall as they are most active and comes near the top of the soil during that period. They feed on the grass during spring and start laying eggs in summer,  and that is when they come close to the surface of the soil. They go underneath the soil during the end of the fall and remain there till mid-spring. You can check detail for best time to treat for grubs.

  1. Can I treat for grubs in spring?

Spring is not the best time to treat the grubs as during this period the grubs feed on the grassroots and also remain deep in the soil.  So, it is best to wait till late summer or early fall to treat the grubs.

  1. How to treat for grubs in the fall?

After confirming the presence of grubs, get rid of them by applying your preferred insecticide onto the brown patches of the lawn. Moreover, fall is the best time to fertilize your lawn to make it healthy, as grubs dislike thick and long grasses for laying eggs.


Treating the grubs at the right time is the key to protect your lawn and to get rid of the white grubs. If you delay in treating them, then the grubs will increase, and it will become even harder to get rid of these insects.

It is best to deal with them when they are still smaller in size, which is during early June-mid August. I hope by reading this article, you will get enough information about when to treat for grubs at the right time.

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