Our Top Fly Parasites for Fly Control
Fly Parasites for Fly Control
Fly parasites for barns, dairies, feedlots — non-stinging wasps that target filth-fly pupae.
01
What it targets
FLYforce™ is a blend of three filth-fly pupal parasitoids — tiny, non-stinging wasps that operators of horse barns, dairies, cattle feedlots, hog and poultry operations, kennels, racetracks, composting sites, and landfills use to break the fly cycle before adults emerge. The species mix in each pouch is Muscidifurax raptorellus, Muscidifurax zaraptor, and Spalangia cameroni — the three commercial pteromalids with the strongest research record against the common house fly (Musca domestica) and the other manure-breeding filth flies (stable fly, lesser house fly, blow flies, soldier flies, etc.). The wasps are pre-parasitized fly pupae shipped in pine shavings; adult wasps emerge over a few days and hunt fresh fly pupae in your manure pack.
Layer FLYforce with the rest of an integrated fly program — tight manure management, regular waste removal, fly tape and bait stations at peak activity windows, and selective use of labelled insecticides only where biology can't reach. The wasps do their best work in the dry zones at the edges of the manure pack and around perimeter fence lines where flies puparate; manure that stays consistently wet and gets removed weekly almost takes care of itself. Use the Fly Parasite Calculator on the site to size the right pouch for the headcount you're running.
02
How it works
An adult fly parasitoid finds a fly pupa, drills the pupal case with her ovipositor, and lays up to five eggs inside. The eggs hatch, the larvae consume the developing fly from the inside out (endoparasitism), and what emerges from the pupal case ten to fourteen days later is a new generation of wasps — not a new fly. Three species in one pouch covers different habits: Spalangia cameroni burrows deeper into the manure pack to find buried pupae; the two Muscidifurax species hunt the surface and the edges. Stacking surface-active and burrowing parasitoids dramatically increases overall suppression by hitting pupae at multiple substrate levels.
The wasps are nocturnal and tiny (a few millimeters long), so you won't see them at work. They don't sting, don't bite, don't bother humans or animals. The cycle they break is the one that matters: parasitized pupae produce wasps instead of flies. Over weeks of regular releases, the standing fly population drops because fewer pupae successfully complete development. They like dry conditions, normal stable temperatures, and a manure pack that isn't being constantly disturbed.
03
Where to use it
Animals and operations
Horse barns & stables
Dairies
Cattle feedlots
Swine operations
Poultry (on wire)
Kennels & pet facilities
Llama / alpaca / sheep / goat
Zoos & racetracks
Other sites
Compost piles
Landfills
Refuse / dumpster zones
Hatching stations
04
Receiving the shipment
Each shipment is a pouch (or bag, for bulk) of pre-parasitized fly pupae mixed with pine-shavings carrier. The package can be held at room temperature briefly, but release within 48 hours of receipt for best emergence. If you need more coverage area than one pouch will reach, mix the contents with additional clean shavings to spread the distribution.
05
Instructions of use
Where to sprinkle
Spread the shavings around stalls, feeding areas, manure storage sites, the edges of the manure pack, and any waste-accumulation zone where flies puparate. Keep releases in protected spots — not in direct hoof traffic, not in standing water, not where rain pounds them down. Compost piles, refuse-disposal sites, and landfills get treated the same way: along the dry edges, not the wet core.
Hatching stations — ant & bird protection
Ants and birds will both raid loose pupae before the wasps emerge. A simple hatching station (covered container with an exit hole for the emerging wasps) protects the pupae through the emergence window. Useful in barns with ant pressure, in open compost areas, or anywhere predation cuts your hatch rate.
Season-long schedule — the part most growers get wrong
Start early to mid-spring, before fly pressure has built. Run releases every 3–4 weeks through the early season, then tighten to every 1–2 weeks as pressure climbs through July and August (peak fly season in most regions). If you wait to start until you're already seeing flies, you're playing catch-up — flies reproduce far faster than the parasitoids do, and a single late start will cost you a doubled rate or two before the population converges. Set up recurring shipments at the front of the season; the operations that succeed all do.
06
Monitoring & advisories
Monitor for
- Sticky fly tape, spot cards, and bait traps in stall corners and around feed bunks — track week-over-week, not absolute numbers.
- Manure sampling for fly pupae and parasitized pupae — parasitized pupae are darker and often have a small round exit hole when the wasps have emerged.
- Adult fly counts in the morning and at dusk — peak activity windows. Falling counts after 2–3 release cycles is the outcome metric.
- Fewer maggots in fresh manure, less buzz around the water troughs, calmer animals at the bunk.
Advisories
- This is living product. Release within 48 hours of receipt; don't refrigerate.
- Wet conditions kill emergence. Don't release where rain or wash-down water pools, and don't put pouches directly under leaking water lines.
- Biological control is one layer — not the whole program. Pair with regular manure removal, fly traps, and selective insecticide use; expect to lean on cultural controls more in dry, dusty barns where fly cycles compress.
- Insecticide compatibility matters — broad-spectrum sprays will kill emerging wasps. Use barrier sprays where flies rest, not in the pupation zones.
- Birds and ants both eat the pupae. Use a hatching station if either is a problem at your release sites.
07
Release rates — by animal type
| Animal type | Quantity per animal group | Cadence |
|---|---|---|
| Horses routine | 7,500 wasps per every 5 horses | Every 2–4 weeks |
| Cattle, Buffalo heavier pressure | 7,500 per every 5 animals | Every 1–3 weeks |
| Goats, Sheep, Dogs routine | 7,500 per every 15 animals | Every 2–4 weeks |
| Miniatures, Burros routine | 7,500 per every 10 animals | Every 2–4 weeks |
| Swine heavier pressure | 7,500 per every 10 animals | Every 1–2 weeks |
| Chickens / Turkeys (on wire) poultry-house | 7,500 per every 2,000 birds | Every 1–2 weeks |
| Ostriches, Emus routine | 7,500 per every 15 birds | Every 2–4 weeks |
| Llamas, Alpacas routine | 7,500 per every 10 animals | Every 2–4 weeks |
| Feedlots, Dairies, Zoos & other consult | Call 1.855.289.1441 for a sizing | Per program |
| Rates are starting points — step up in peak fly months and after a missed release. Recurring scheduled shipments are the cheapest way to keep the schedule honest; ask about a season-long subscription at order time. | ||
⚑
The timing trap
Start before you see flies. Most programs that fail start too late. Release in early to mid-spring at the modest rates above; by the time peak pressure hits in July–August you'll already have generations of parasitoids resident in the manure pack. If you start mid-season, plan on at least one or two doubled rates before the population catches up.
08
Life cycle
The whole egg-larva-pupa development happens inside the host fly pupa. What you see externally is a darkened, hardened pupal case with a clean round exit hole once the wasps emerge.
1
Egg
2
Larva
3
Pupa (in host)
4
Adult
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 in field settings. Many variables affect fly-parasitoid performance: insecticide applications, manure management practices, ant and bird predation on pupae, weather, and the existing fly population at the time of first release. 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 released.
This is one layer of an integrated program. Sound manure management, sticky and bait trapping, and selective use of labelled insecticides remain essential. The wasps make all of those layers more effective; they don't replace them.