When you think about protecting your lawn and garden from pests, microscopic organisms probably aren't the first thing that comes to mind. But beneath the soil, beneficial nematodes can play an important role in managing certain insect pests.
These microscopic roundworms occur naturally in soil, and specific species are used as biological pest-control products. Once applied correctly, they seek out susceptible pest larvae or other immature insect stages in the soil.
Understanding what nematodes are, why they're used, when and where to apply them, and how to apply them properly can help gardeners get better results.
What Are Beneficial Nematodes?
Nematodes are microscopic, worm like organisms found naturally in many environments. There are thousands of species, and they don't all behave the same way.
Some nematodes feed on plants, fungi, or bacteria, while others are entomopathogenic nematodes, meaning they parasitize insects. These are the beneficial nematodes used in many biological pest-control products.
After entering a susceptible insect host, the nematodes release symbiotic bacteria that multiply and kill the host. The nematodes then reproduce inside it before their offspring move back into the soil in search of additional hosts.
So while you can't see them working, there's a lot happening beneath the surface.
Why Do Gardeners Use Nematodes?
Beneficial nematodes provide gardeners with a biological way to target certain pests during vulnerable stages of their life cycles.
Depending on the nematode species and product, they may be used against pests such as:
- White grubs
- Fungus gnat larvae
- Flea larvae
- Certain weevil larvae
- Cutworms
- Other susceptible soil-dwelling insect stages
One of the biggest advantages is that properly selected beneficial nematodes target susceptible insect hosts rather than acting like a broad-spectrum insecticide.
However, nematodes aren't a universal solution. Different nematode species target different pests, so identifying the pest first is an important part of choosing the right product.
Who Should Consider Using Nematodes?
Beneficial nematodes can be useful for homeowners and gardeners dealing with a pest that spends a susceptible stage of its life in soil or another moist growing medium.
They may be appropriate for:
- Home lawns
- Vegetable gardens
- Flower beds
- Ornamental gardens
- Raised beds
- Greenhouses and containers, depending on the target pest and product
Before applying anything, determine what pest is actually causing the damage. Brown grass, damaged roots or struggling plants can have many causes, and applying nematodes for the wrong pest won't solve the problem.
When Should Nematodes Be Applied?
Timing is one of the most important parts of successful nematode application.
Nematodes need to be applied when their target pest is present in a vulnerable stage. The ideal timing therefore varies depending on the pest and nematode species you're using.
Environmental conditions matter too. Because beneficial nematodes are living organisms, they require moisture to move through the soil.
For best results:
- Follow the temperature requirements listed on the product.
- Apply when the soil is moist.
- Avoid applying to extremely hot or dry soil.
- Avoid intense sunlight when possible because ultraviolet light can harm nematodes.
- Evening or cloudy conditions can be useful for application.
- Keep the treated area appropriately moist after application according to the product directions.
Don't rely on the calendar alone. The target pest's life cycle and the product label should determine your application timing.
Where Do Nematodes Work?
Beneficial nematodes work best where their target insects are located and where there is enough moisture for the nematodes to move.
Depending on the product, this could include:
Lawns: Certain nematodes may be used against susceptible soil-dwelling larvae beneath turf.
Garden beds: They may help manage particular pests living around plant roots or in the surrounding soil.
Containers and greenhouses: Certain species can be used against pests such as fungus gnat larvae in moist growing media.
Applying nematodes to the wrong location is unlikely to help. If the target pest lives primarily on leaves while the nematode species you're using hunts underground, the two may never meet.
How Do You Apply Beneficial Nematodes?
Nematodes are living organisms, so proper handling is essential.
1. Read Your Product Instructions
Always begin with the directions for the specific nematode product you're using. Storage requirements, application rates, compatible equipment and temperature ranges can vary.
2. Prepare the Area
If the soil is dry, it may need to be watered before application. Moist soil provides the environment nematodes need to move and locate hosts.
3. Mix as Directed
Nematode products are generally mixed or dispersed in water according to their package instructions.
Keep the solution moving or agitated when directed because nematodes can settle.
4. Apply to the Target Area
Depending on the product, application may be made using equipment such as a watering can, sprayer or hose-end nematode applicator.
If using a sprayer, follow the product directions regarding filters, screens, pressure and nozzle openings. Equipment that isn't suitable for living nematodes can reduce the number that reach the soil alive.
5. Water Them Into the Soil
After application, irrigation is often used to wash nematodes from the plant or grass surface and into the soil where the target pests are located.
6. Maintain Moisture
Don't allow the treated soil to immediately dry out. Follow the product's directions for post-application watering so the nematodes have time to move through the soil and find hosts.
Why Moisture Matters So Much
Think of nematodes as microscopic organisms that need a thin film of water around soil particles to move effectively.
If the soil becomes too dry, their movement and survival can decline. On the other hand, the goal isn't to leave the lawn or garden waterlogged.
Moist, not flooded, is the general idea, with the specific product directions taking priority.
Are All Nematodes Good for Your Garden?
No, and this is an important distinction.
"Nematode" describes an enormous group of organisms. Some are harmless, some play useful roles in soil ecosystems, some are used for insect pest management, and others are plant-parasitic nematodes that can damage plant roots.
The products sold for biological insect control contain specifically selected beneficial, insect-parasitic species.
That's why simply saying "nematodes kill garden pests" isn't quite accurate. The right nematode must meet the right pest at the right stage and under suitable conditions.
Common Nematode Mistakes to Avoid
Even a good product may perform poorly when it's applied incorrectly. Common mistakes include:
- Applying nematodes without identifying the pest
- Choosing a nematode species that doesn't target that pest
- Applying when the target insect isn't at a susceptible stage
- Letting the soil become too dry
- Leaving the product in hot conditions or direct sunlight
- Using unsuitable application equipment
- Ignoring storage or expiration instructions
- Assuming one application will control every type of garden pest
Remember, these are living biological controls, not conventional chemical pesticides. How they're stored and applied matters.
Beneficial nematodes may be tiny, but when they're matched with the correct pest and applied under the right conditions, they can be a useful addition to an integrated pest-management plan.
Success comes down to three things: identify the pest, choose the appropriate nematode product, and apply it correctly. Pay particular attention to timing, soil moisture, temperature, sunlight and the instructions provided with your product.
With a little knowledge about what's happening beneath your lawn or garden, these microscopic helpers can become another useful tool in your gardening routine.
🌱 Give Your Garden a Helping Hand
Visit Ritchie Feed & Seed to explore beneficial nematodes and application supplies for your lawn and garden. https://www.ritchiefeed.com/
