This is safe, effective biological control for indoor and outdoor use. People, pet, and planet-safe, and trusted by professionals. Application is simple: mix the easy-release powder with water and apply like you're watering your plants, no special equipment required.
Fungus Gnat, Thrips Pupae, & Cool-Season Soil Pest Control
Fungus gnat larvae and thrips pupae live right in the top layer of growing medium — exactly where Steinernema feltiae (Sf) operates. It stays active in cooler soil temperatures that would slow other species down, making it the standard choice for greenhouse and container pest problems.
Widely used in greenhouse settings and shoulder-season applications, Sf is the nematode of choice when cold tolerance and fungus gnat control are the priority.
What Are Beneficial Nematodes?
Sf uses an intermediate foraging strategy, sometimes described as "shallow cruising," that falls between Sc's sit-and-wait ambush style and Hb's deep, active cruising. It works the shallow upper layer of soil or growing medium rather than the surface (Sc's zone) or the deeper root zone (Hb's zone) — which is exactly where fungus gnat larvae, shore fly larvae, and thrips pupae actually live.
What do Sf Nematodes Target?
Targets fungus gnats (Sciarid), thrips pupae, cabbage maggot, gall midge, humpbacked (phorid) flies, leafminers, onion maggot, root maggot, lesser cornstalk borer, raspberry crown borer, and ticks (in combination with Hb). Plus armyworms, codling moth, cutworms, garden webworms, hornworms, webworms, asparagus beetle, Colorado potato beetle, cucumber beetle, white grub, billbug, mint root borer, crane fly, house & filth fly, shore fly, ant queens and red fire ants, and flea larvae/pupae, shared with Hb and/or Sc.
How It Works
The life cycle follows the same pattern as other beneficial nematodes: eggs hatch into non-feeding juveniles, which molt into infective juveniles that search the shallow soil layer for hosts, infect them with bacteria, and feed on the cadaver before repeating the cycle. What sets Sf apart is timing tolerance — it's the most cold-tolerant of the three species we carry.
When to Use Sf Nematodes?
Optimal application when soil temperature is between 59°F and 79°F
- Early Spring (Mar-Apr): Target overwintering pests once soil temperatures reach 42°F+
- Late Spring/Early Summer (May-Jun): Interrupt first-generation pests to prevent summer pest outbreaks
- Mid-Summer (Jul-Aug): Maintain control during peak pest activity
- Fall (Sept-Oct): Reduce next year's pest problems by applying nematodes before pests go into dormancy for winter
Application Rates
These are general starting points — actual application should be adjusted based on pest species, plant type, and infestation severity. Monitor pest and predator populations regularly to gauge how well the program is working.
| Application | Rate |
| Preventative/Light Infestation | 5 million nematodes per 300 sq. ft. |
| Moderate/Heavy Infestation | 5 million nematodes per 50 sq. ft. |
Soil Temperature & Moisture
- Optimal Soil temperature: 59°F - 79°F (General soil temperature 42°F-95°F)
- Sf needs consistently moist soil. Avoid drying out
- Keep soil moist for two weeks following application; avoid runoff
Application
Nematodes aren't a chemical, so effectiveness isn't reduced by the water volume used. Adjust concentration based on infestation severity and area size. Introduce indoors at any time, or outdoors in the morning, evening, or on a cloudy day; nematodes are sensitive to UV light, so direct sunlight should be avoided.
Application Instructions
- Prepare Soil — ensure soil is moist before application; dry soil prevents nematode movement.
- Activate/Mix Solution — mix nematodes with 59–69°F water; water volume depends on infestation level and treatment area size.
- Apply Evenly — distribute using a sprayer, watering can, or irrigation system.
- Keep Moist — water immediately after application and maintain soil moisture for 2 weeks; avoid runoff or waterlogging.
Watering Can or Pump Sprayer:
- Moisten the soil beforehand to improve habitat; avoid runoff.
- Mix nematodes with 1–5 gallons of water (59–69°F) to cover the desired area, diluting as needed for coverage.
- Apply the solution to the desired area — full, even coverage isn't necessary, since nematodes will move through the soil on their own. Use within 6 hours of activation.
- Water the treated area immediately after application, and keep soil moist for two weeks.
Hose-End Sprayer:
Use room-temperature water and let the nematode powder sit for 15 minutes to fully dissolve before spraying. Remove any screen filter first.
| 5 million | Add all nematodes to the reservoir, fill to the 5 gallon mark. Spray until empty. |
| 10 million | Add all nematodes to the reservoir, fill to the 10 gallon mark. Spray until empty. |
| 25 million | Divide in half. Fill reservoir to the 15-gallon mark, mix in one half, spray until empty. Repeat twice. |
| 50 million | Divide into thirds. Fill reservoir to the 15-gallon mark, mix in one third, spray until empty. Repeat three times. |
Other Hose-End Sprayers (dial-style):
Use room-temperature water and let the nematode powder sit for 15 minutes to fully dissolve before spraying. Remove any screen filter first.
| Package Size | Preventative/Light | Moderate/Heavy |
| 5 million | 4 oz | 8oz |
| 10 million | 4 oz | 8 oz |
| 25 million | 1.5 oz | 8 oz |
| 50 million | 4 tsp | 5 oz |
Pairing for Full-Spectrum Soil-Pest Control
Sf nematodes work well alongside Hypoaspis miles for layered soil coverage. Nematodes work deeper in the soil profile targeting grubs and beetle larvae, while Hypoaspis miles patrol the surface layer for fungus gnats and thrips pupae. For broader soil-pest coverage in a single treatment, HB is also available blended with SF and SC nematode species.
Safe, Sustainable Pest Management
- 100% natural — no chemical residue
- Safe around people and pets
- Safe for use on edible crops
- Fits seamlessly into existing IPM programs
- Requires no protective equipment
Storage
Your nematodes arrive in a bubble mailer with an ice pack — the ice pack will likely be melted and the package may feel warm on arrival. This is normal; the product remains safe to use. Refrigerate the unopened package until ready to apply. If storage is necessary, store at 36–45°F for no more than 30 days, in a dark place. Do not freeze.