Our Top NEMAforce™ SF for Fungus Gnat control

NEMAforce™ SF – (50/250 million)

$46.78

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NEMAforce™ SF for Fungus Gnat control

Beneficial nematodes that kill fungus gnat larvae in 24–48 hours — Steinernema feltiae.

What it targets

NEMAforce™ SF is Steinernema feltiae — an entomopathogenic nematode (EPN) that hunts fungus gnat larvae in the top inch or two of growing media. The vendor's primary targets are fungus gnat larvae (Sciaridae — Bradysia, Sciara, Lycoriella), shore fly larvae, mushroom fly larvae, and the soil-pupating stages of western flower thrips, onion thrips, and several other thrips species. The larvae are the only stage of these pests that damage roots; nematodes kill them before they can pupate into the adults you see on your sticky cards.

Pair NEMAforce™ SF with Amblyseius cucumeris on the foliage side of a thrips program — cucumeris hits the 1st larval instar on leaves, NEMAforce SF cleans up the pupae dropping into the media. For long-term fungus-gnat suppression, layer with Dalotia coriaria or Stratiolaelaps scimitus: the nematodes deliver the knock-down on hot spots, the rove beetles and predatory mites stay resident in the media for the long preventive layer.

Adult fungus gnat (Bradysia) — the dark-winged fly whose larvae NEMAforce SF kills in the soil — Adult fungus gnat (*Bradysia*) — the dark-winged fly you see on sticky cards. NEMAforce™ SF kills the larvae in the soil before they can pupate into the next generation of adults.

How it works

The infective juvenile (IJ) stage of Steinernema feltiae is what ships in the tray. IJs enter a host larva through a natural opening — mouth, anus, spiracle — and once inside they release a symbiotic bacterium, Xenorhabdus sp. The bacterium does the killing; the larva dies in 24–48 hours. The nematodes then grow and reproduce inside the cadaver, and the next generation of IJs leaves the dead host in search of fresh prey. One application becomes self-replicating in the media as long as conditions stay favorable.

S. feltiae is the right EPN for shallow, active pests because it lives 1–2 inches below the media surface and uses a mixed "cruising + ambush" foraging style — it doesn't burrow deep, and it actively follows prey cues rather than just sitting in wait. Optimal soil temperature is 50–78°F (10–26°C); below 50°F activity stalls, and above ~85°F the nematodes desiccate quickly. Moisture matters as much as temperature: the media surface needs to be moist when you apply, and you have to keep it moist for at least two weeks after for the IJs to find hosts and reproduce.

Steinernema feltiae nematode under a microscope — the infective juvenile stage — *Steinernema feltiae* infective juvenile — a microscopic nematode roughly 0.5–1 mm long. Each tray contains millions; you'll never see one without a microscope.

Crops, environments, and climate

Crops it supports

Ornamentals Hemp / Cannabis Vegetables Mushrooms Soft fruits Tree nurseries

Environments

Greenhouses Indoor facilities Propagation houses Hydroponic systems Mushroom cultivation

Storage & disposal

On receipt, remove the trays from the shipping packaging and either use immediately or refrigerate at 41°F (5°C). Do not freeze. Ensure good air circulation around each tray in the cooler. Check the expiration date on the package — do not use product that's expired or has been incorrectly stored. Unused or outdated product (and packaging) can be disposed of on-site or at any approved waste-disposal facility per federal and local regulations.

Mixing & application

Equipment prep

NEMAforce™ SF goes through standard spray equipment: tank sprayers, backpack sprayers, and irrigation injection systems. Remove filters 50 mesh or finer from the equipment and nozzles — the nematodes are larger than fine-mesh openings and will be filtered out. Don't exceed 300 psi pump pressure (high pressure damages the IJs). Don't use systems with nozzle apertures smaller than 0.5 mm.

Mixing the tank

Moisten the media to about 75% capacity before application. Fill the spray vessel or stock tank with half the required volume of cool, clean water. Start agitation, then add the required number of nematode trays. Continue agitating while you fill the tank to the final volume. The total spray volume needs to be enough to wash nematodes down to 1–2 inches below the media surface. Maintain agitation through the entire application — nematodes settle out fast.

Application timing

Apply early morning or evening to avoid daytime desiccation. If you're spraying foliage (for thrips), do it on an overcast day, use as little water as possible to cover the leaf surfaces, add a wetting agent, and keep humidity high — a light mist of plain water about 30 minutes after application helps. Maintain media moisture for at least two weeks after application so the IJs can find and reproduce in hosts. Do not spot treat — treat the entire crop at the appropriate rate.

Monitoring & advisories

Monitor for

Yellow sticky cards placed just above the soil level — track adult fungus gnat counts week-over-week. Sticky cards monitor; they don't control.
The potato-slice test: drop a thin slice of raw potato cut-side-down on the media for 24 hours; fungus gnat larvae will burrow into it and confirm presence/density.
Reduced larval activity in the media 7–10 days after application — the outcome that matters. You won't see the nematodes themselves; S. feltiae is microscopic.
Fewer adults on sticky cards 10–14 days after application as the larval generation fails to pupate.

Advisories

Do not subdivide a tray. Once opened, use the entire tray immediately — partial use destroys the gel matrix that keeps IJs viable.
Use cool water for mixing; keep the tank out of direct sunlight. Heat kills IJs in minutes.
Strip out fine filters (50 mesh or finer) from spray equipment. Cap pump pressure at 300 psi. Nozzles must be 0.5 mm or larger.
Soil temperature is the limit. S. feltiae works at 50–78°F (10–26°C); above ~85°F or below 50°F activity drops sharply.
Maintain media moisture for at least two weeks after application. Dry media kills IJs faster than anything else.
Pair with Dalotia or Stratiolaelaps for season-long resident control — nematodes are knock-down, the soil predators are persistent.

Application rates — for conventional crops

Target & pressure	Rate	Spray volume
Soil / media — preventive routine	50M per 1,100 sq.ft. · 250M per 5,500 sq.ft.	30–50 gal per 1,000 sq.ft.
Soil / media — lower frequency maintenance	50M per 550 sq.ft. · 250M per 2,750 sq.ft.	~30–50 gal per 1,000 sq.ft.
Foliage — light thrips infestation step up	50M per 4,400 sq.ft. · 250M per 22,000 sq.ft.	~2.5 gal per 1,000 sq.ft.
Foliage — heavy thrips infestation outbreak	50M per 2,200 sq.ft. · 250M per 11,000 sq.ft.	~2.5 gal per 1,000 sq.ft.
Soil applications: repeat every 2–3 weeks (preventive cadence) or every 4–6 weeks (maintenance). Foliage applications: once or twice weekly through the infestation. Trays come in 50 million and 250 million IJ sizes.

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Cannabis Alert

Conventional release rates are usually not sufficient for cannabis growers. We recommend you double the rate or contact us for personalized help. NEMAforce™ SF integrates cleanly with most cannabis IPM programs — zero REI, no residue, safe up to harvest — making it one of the few options for late-flower fungus gnat or thrips pressure.

Life cycle

Steinernema feltiae runs most of its life cycle in vivo — inside the body of a host insect. Only the third-stage infective juvenile leaves the dead host to find new prey. The IJs in your tray are that dispersal stage.

Stages 1–3

In-vivo inside the host larva

Stage 4 (IJ)

Exits dead host, searches for new prey

Infection

24–48 hr kill via Xenorhabdus bacterium

Adult

In-vivo · reproduces in the cadaver

See it in action

Disclosures

Live-product policy. Beneficial Insectary works to guarantee live delivery of fresh organisms. Replacements or credits are offered for compromised shipments when issues are reported within 24 hours of receipt — and before any organisms suspected of viability issues are released. Don't discard the product; you may be asked to return the shipment for analysis.

Establishment of biocontrol agents. Many variables — pesticide applications, watering practices, storage, cultural and physical controls — affect EPN and pest populations across crops. Cool media, high humidity, and continuous moisture make all the difference. Because of these variables, long- or short-term establishment cannot be guaranteed after release, and refunds, discounts, or credits are not offered on products that have already been applied.

Worker safety. Steinernema feltiae is a registered biological pesticide that's exempt from federal residue tolerance requirements and carries a 0-hour REI. Safe for workers, beneficial insects, pets, and pollinators on the crop.