Using Beneficial Nematodes To Control Garden Pests

Beneficial nematodes are a healthy and all-natural proactive pest solution that kills bugs before they ever have a chance to destroy your plants. In this post, I’ll tell you exactly how they work and when to apply them. Then I’ll give you step-by-step instructions for how to spread nematodes in your garden.

Skip the chemical pesticides this season. Beneficial nematodes are a totally organic, chemical-free solution to your garden pest insect problems.

With these natural predators, you can control damaging bugs before they ever emerge from the soil. The best part is that they only attack the bad bugs, and won’t harm pollinators or other beneficial insects.

These helpful nematodes will kill the grubs that grow into detrimental insects before they ever have a chance to eat your plants. When applied correctly, they will continue to protect your garden all season long.

Below, I will tell you how they work, and show you when and how to apply them in order to keep your garden pest-free.

Here’s what you’ll find in this guide for using beneficial nematodes to control garden pests…

What Are Beneficial Nematodes

Beneficial nematodes are microscopic organisms that are commonly used to control many different types of garden insect pests.

They live in the soil, where they are found naturally. Plus, they’re completely organic, non-toxic, and safe to use around people and pets.

Types Of Beneficial Nematodes

It’s important to understand that there are different types of beneficial nematodes, and their prey can vary by species. All kinds will feed on various pest insect larvae, but they don’t feed on everything.

So, for best results, you should know what type of insect pest you’re targeting. That way, you can be sure to get the best type of nematodes that prey on that specific pest.

Check the package to make sure the kind you buy targets your specific insect pest. If you have more than one kind of bug you want to get rid of, you may need to apply different species of beneficial nematodes. Don’t worry, they won’t harm each other.

Some packages come with several different species mixed together, so one application can target a larger array of bad bugs. So, if you’re targeting multiple pests, you may want to buy a mixed package.

What Do Beneficial Nematodes Look Like?

They are invisible to the naked eye. However, if you were to look at them under a microscope, beneficial nematodes look like long roundworms.

Sounds gross, I know, so it’s probably a good thing that we can’t see them. Don’t worry, they won’t crawl on you or anything like that. They live underground.

Box of beneficial nematodes and supplies for applying

Are Nematodes Good For Your Garden?

There’s no question that beneficial nematodes are good for your garden. They help to naturally control tons of different pest insects. That means you don’t have to worry about using harmful pesticides in your yard. Yeah!

However, if you don’t have any trouble with bad bugs, then there’s no reason to apply them. They don’t have any other benefit to the garden, and will only die off if there’s not a large population of pray for them to feed on.

What Do Beneficial Nematodes Kill?

Beneficial nematodes kill grubs and other insects when they’re in their larval and pupal stages in the soil, before they emerge as adults. Though they attack most soil-dwelling bugs, they leave earthworms alone.

Since they kill over 200 different types of insects, I won’t attempt to name them all here. But, on a large scale, beneficial nematodes can be used to control fleas, beetles, ants, flies, termites, and many other types of undesirable bugs.

Grub worm in my garden

Do Beneficial Nematodes Really Work?

Yes, absolutely. It’s hard to trust that they are doing anything, since you can’t see them. And you’re not going to see any dead bugs around either, because they all die underground.

But after a few weeks, you should start to notice the population of the adult bugs is beginning to decline.

I’ve definitely seen a significant decrease in the amount of flea beetles and ants in my gardens, and the Japanese beetle population seemed smaller the last few years too.

How Do Beneficial Nematodes Work?

They are parasites that enter the body of their host, and then release a type of bacteria that kills them. The beneficial nematodes then feed on the dead grubs from the inside out. Once they’re done, they move on to find another host.

Sounds horrible, doesn’t it. Well, there’s more! They also mate inside the host, where the babies feed on the dead insect as they grow as well. Eek! I’m glad I’m not a bug.

Once the pest population dies down, the nematodes also start to naturally die off. So, it’s usually best to reapply at least once a year for recurring pest infestations.

How To Use Beneficial Nematodes

In this section, I’ll give you some general guidelines for when and how to apply beneficial nematodes in your yard and garden.

But, you should always follow the instructions on the package. Those will give you the best methods for mixing and applying your purchased species.

Container of 7 million nematodes

When To Apply Beneficial Nematodes

If you’re wondering what time of the year to apply beneficial nematodes, it somewhat depends on what you’re trying to control.

Once the adult bugs emerge, these useful parasites do not affect them. So it’s important to apply the nematodes at the right time, while the larvae is still in the ground.

So, for example, late spring or early summer is the best time to apply them for Japanese beetles, because the larvae are very close to the soil surface at that time.

Late summer into early fall is also a good application time, so they’ll kill the soil-dwellers before they have a chance to overwinter.

As for the time of day to do it, beneficial nematodes travel best when the soil is moist, and direct sunlight will kill them. So, if you can, plan to apply them on a cloudy and/or rainy day when the temperature is between 45-95 degrees F.

If it’s not cloudy, then the best time of the day to do it is after the sun goes down in the evening, to avoid any direct sun exposure.

How To Apply Beneficial Nematodes

Applying beneficial nematodes is a pretty easy process. Before starting, make sure you read the instructions on the package. But below are the basic steps.

It’s important to apply them right after mixing with water. You can’t store them after they’ve been activated. So allow at least one hour of time in order to complete all of these steps.

You don’t need any fancy equipment, and will probably have the necessary supplies around the house.

Supplies Needed:

• Beneficial nematodes
• Hose end sprayer attachment or hand pump sprayer
• Garden hose (if using a hose sprayer)
• 5 gallon bucket
• Water
• Strainer or screen material (optional: if yours came in packing material)

Nematodes sprayer for garden hose

Step 1: Activate the beneficial nematodes – First, pour the container of nematodes into water, and allow them to soak. This will activate them.

To do this, pour about 1 gallon of tepid water into a 5 gallon bucket, and then add the contents of the package. Stir it all together, and let it sit for 30 minutes.

Step 2: Water the yard – While your beneficial nematodes are soaking, water your yard and gardens thoroughly (if it’s not raining).

Do not skip this step because they travel best in damp conditions. The soil should be moist, but not saturated or soggy.

Soaking nematode solution in water

Step 3: Strain out the packing material – If your nematodes came in packing material like mine did, then you should strain out the largest pieces to avoid clogging your sprayer.

You can use a kitchen strainer or a piece of old screen material to do this. Remember, they are invisible to the naked eye.

So you’re not going to see anything swimming around in the water. You just have to trust that they are in there.

Step 4: Add the mixture to your sprayer – Fill your hose sprayer attachment or with the water and nematode mixture, or add a small amount to your hand pump.

If you’re using a manual pump sprayer, you’ll need to add more water to the mixture to further dilute it, so the application will go farther. To avoid blockage, remove any screens or filters in your sprayer.

Step 5: Apply the beneficial nematodes – Now you can simply walk all around, spraying the mixture in your yard and gardens as you go.

Shake the sprayer once in a while as you’re applying to make sure the beneficial nematodes are being distributed evenly, and not sinking to the bottom.

Step 6: Water your yard again – Once you’re done spraying, thoroughly water your yard and gardens again, so the nematodes have plenty of moisture to move around. You’ll also want to keep the soil moist for a week or two if there’s no rain in the forecast.

Spraying beneficial nematodes in my yard

FAQs

In this section, I’ll answer some of the most frequently asked questions about using beneficial nematodes for pest control. If you can’t find an answer to your question here, then ask it in the comments below.

How long does it take for nematodes to work?

Though it only takes a day or two for beneficial nematodes to start killing pests, it takes a bit of time before you’ll start to notice a change.

You should start to see a difference in about 2 weeks, as the emerging adult populations slowly begin to decrease.

Do beneficial nematodes survive winter?

Beneficial nematodes go dormant during the winter, and can survive until spring. However, in climates with harsh winters (like ours here in Minnesota), many of them will die off.

So the population can decrease quite a bit during the winter. That’s why it’s a good idea to reapply them every year.

Are beneficial nematodes harmful to humans?

No. Beneficial nematodes are completely harmless to humans, pets, and other animals, as well as insects like ladybugs, bees, and other pollinators, birds, fish, amphibians, and reptiles.

Is it safe to apply beneficial nematodes in my vegetable garden?

Yes! Beneficial nematodes are all-natural, non-toxic, and completely safe to use in any area of your yard, including the vegetable garden.

Beneficial nematodes are a great way to use nature to control harmful garden bugs. With only one application each year, they will go on killing the pests, all while leaving your beneficial insects and pollinators alone.

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• How To Protect Grapes From Birds & Insects
• All About Ladybugs & Why They’re Good For Your Garden
• Grapevine Beetle Information & Organic Control Tips

Share your tips or experience with using beneficial nematodes for garden pest control in the comments below.