Beneficial Nematodes

Tier A — Proven Safe Biological OMRI Listed

Quick Facts

Type
Biological
Source
Naturally occurring soil-dwelling roundworms, primarily Steinernema and Heterorhabditis species
OMRI Listed
Yes ✓
Bee Safe
Yes
Pet Safe
Yes
Residual
Self-reproducing in favorable soil conditions; may persist for months
Best For
Soil-dwelling larvae: grubs, fungus gnat larvae, root maggots. Long-term biological suppression.

What Is Beneficial Nematodes?

Microscopic worms actively seek soil-dwelling larvae, enter through natural openings, and release symbiotic bacteria that kill the host within 24-48 hours. Nematodes reproduce inside the dead host and release a new generation to find more prey.

Source: Naturally occurring soil-dwelling roundworms, primarily Steinernema and Heterorhabditis species

What Pests Does Beneficial Nematodes Kill?

Beneficial Nematodes is effective against the following pests:

Fungus Gnats Japanese Beetles Flea Beetles Fire Ants Caterpillars (General)

How to Apply Beneficial Nematodes

Best for: Soil-dwelling larvae: grubs, fungus gnat larvae, root maggots. Long-term biological suppression.

Avoid for: Above-ground pests, dry sandy soils without irrigation, frozen ground.

Residual activity: Self-reproducing in favorable soil conditions; may persist for months

Safety Profile

CategoryRating
Bee Safety 🟢 Safe for bees
Pet Safety 🟢 Safe for pets
Overall Rating Safe — Safe for kids, pets, and bees when used as directed

Why Isn't Beneficial Nematodes Working?

If Beneficial Nematodes isn't delivering results, check these common failure modes:

Soil too dry — nematodes need consistent moisture to move through soil

UV exposure — apply in evening or on cloudy days; UV kills them on contact

Soil too cold — most species need soil temps above 55°F for activity

Wrong species — Steinernema feltiae for fungus gnats; Heterorhabditis for grubs

Dead on arrival — nematodes are living organisms; check viability before applying

Best Beneficial Nematodes Products

NaturesGoodGuys Nematodes

Live organisms

Steinernema feltiae — fungus gnat specialist

BioLogic Scanmask

Live organisms

Steinernema feltiae — established brand

NemAttack Hb

Live organisms

Heterorhabditis bacteriophora — grub specialist

Sources and Further Reading

Related Ingredients

Bacillus thuringiensis (Bt)

Tier A

Bacillus thuringiensis (Bt) is the most proven organic caterpillar control available. This naturally occurring soil bacterium produces proteins that destroy caterpillar gut linings within 24-72 hours while remaining completely safe for bees, pets, and beneficial insects.

Spinosad

Tier A

Spinosad is a naturally derived insecticide that kills thrips, caterpillars, leafminers, and fire ants through nervous system disruption. OMRI-listed and effective, but must be applied in evening hours to protect pollinators.

Insecticidal Soap

Tier A

Insecticidal soap kills aphids, whiteflies, spider mites, and mealybugs on contact by disrupting their cell membranes. It has zero residual toxicity, is safe for bees and pets, and can be made at home with pure castile soap.