Beneficial Nematodes, Let Them do Your Dirty Work

How Microscopic Worms can Get Rid of Grubs and Other Soil Pests

When you choose an organic approach to caring for your outdoor lawn and landscape, the goal is help build up healthy populations of beneficial insects that can help you keep the bad bugs at bay. Ladybugs, lacewings, praying mantis and other beneficial insects can help you control invasions of destructive pests without the use of chemicals. While most of these beneficial insects live above ground, there is one very important beneficial critter you may never know is there...the beneficial nematode.

Beneficial nematodes help control lawn pests such as grubs.

What are beneficial nematodes?

Beneficial nematodes are are microscopic, non-segmented round worms that live and multiply in the soil. These are not to be confused with pest nematodes, such as root-knot nematodes that can cause a lot of plant damage. Beneficial nematodes prey on insects in their larval stage underground. However, they are known to sometimes feed above ground on the adults of insects such as fire ants.

If you have persistent problems with grubs (the larval stage of the June beetle), fire ants, fleas or chiggers, beneficial nematodes might just be your best weapon.

But that’s not all beneficial nematodes eat...in fact they can control about 230 different kinds of insects including:

• Japanese beetles

• Cut worms

• Wire worms

• Weevils

• Fungus gnat larvae

• TICKS - yes ticks. While nematodes will have less limited control efficacy on young larvae, they've actually shown to have a bigger impact on engorged female ticks in the soil
  
  

How do they operate? Nematodes kill their target by burrowing into the larva’s body cavity, then releasing a bacterial that kills it. YIKES.

One of the biggest benefits of using beneficial nematodes is that they won’t harm earthworms in your soil, or reptiles, pets, or people. Plus, they get along nicely with other beneficials such as ladybugs and their larvae since ladybug larvae don’t pupate near the soil.

How do you apply them?

You release beneficial nematodes by simply mixing them into water, then spraying or pouring them onto your soil. The early morning or evening is a great time to apply them to your landscape, as they prefer cooler soil temperatures. Don’t plan to apply them during the heat of the day. It’s best if your soil is healthy and the texture is loose. Remember, healthy, crumbly soil full of bioactivity is the best breeding ground for microbes and insects that benefit your landscape.

And yes, you can also add beneficial nematodes to container grown plants, greenhouse plants, and houseplants to control root damaging pests.

Once you have applied your beneficial nematodes, you’ll want to ensure the soil doesn’t completely dry out soon after. Keeping your soil moist will ensure their populations thrive and multiplies. Once your beneficial nematodes are living underground, they are still susceptible to non-selective pesticides. So avoid spraying them after you’ve put down nematodes.

Keep in mind that it will take a few weeks for the nematodes to begin having an effect. As with all organic methods, patience is key. A healthy population of beneficial nematodes may continue controlling soil pests for several years, or you may want to re-apply them annually in areas where soils dry out regularly.

What about dry heat?

It's important to note that beneficial nematodes do require some consistency of dampness in the soil as well as some shade, so you'll find they are less effective in the hottest part of the summer in full sun lawn areas. But the spring and fall seasons are the best times to deploy nematodes and weather conditions are more favorable for them during these times. Since fall is right around the corner, now's the time to plan you fall nematode applications.

And of course you can use them 365 year-round in potted plants or indoor houseplants.