ERETforce™ for Whitefly Control
Eretmocerus eremicus — an ectoparasitic wasp for Bemisia whitefly control.
01
What it targets
ERETforce™ is Eretmocerus eremicus, a tiny (~0.8–1 mm) ectoparasitic wasp native to the southern California and Arizona deserts. Its primary host is the tobacco / sweet potato whitefly (Bemisia tabaci, MEAM1 includes what was formerly called silverleaf, B. argentifolii). It also handles other Bemisia species and can take some Trialeurodes as a secondary host, but for a clean Trialeurodes vaporariorum (greenhouse whitefly) job, switch to Encarsia formosa instead — that’s the species-match call most growers get wrong on the first release.
Eretmocerus is best released early — preventively or against low-to-medium pressure — before whitefly populations explode. On crops with severe established outbreaks, knock down the adults with a selective insecticide first, wait the residue out, then bring Eretmocerus in for sustained control. The wasp ships as parasitized whitefly scales (pupae) on hanging cards, blister packs, or loose in vials with bran flakes — the format depends on the SKU.
02
How it works
The mechanism is the most important detail on the page. Eretmocerus eremicus females lay eggs underneath 2nd, 3rd, and 4th instar whitefly nymphs (preferring the 2nd) — this is ectoparasitism. The wasp larva hatches outside the host, then chews its way in and develops through three larval stages, slowly killing the nymph from inside. The parasitized scale darkens to a gold-brown as the wasp develops, and pupation completes inside a light-brown case visible on the leaf underside. This differs from Encarsia formosa, which lays eggs inside the same nymphal stages (endoparasitism) and turns the scale black. Two parasitoids, same host stages, different parasitism modes — useful when you want to layer them on a mixed Bemisia + Trialeurodes outbreak.
Each Eretmocerus female parasitizes up to 150 whitefly nymphs over her lifespan. Roughly 50–65% of every release is female. Beyond parasitism, Eretmocerus shows significant host-feeding activity — the female pierces and consumes additional whitefly nymphs directly, on top of those she parasitizes. UMass Extension and ScienceDirect reviews note this host-feeding can be a major mode of pest suppression separate from parasitism alone, effectively making Eretmocerus part predator on top of being a parasitoid.
Heat tolerance — the desert origin advantage
Optimal performance runs 70–95°F with relative humidity at or below 60%. Because the species is native to American deserts, it tolerates daytime peaks reported as high as 113°F as well as cool desert nights — making it the right pick for greenhouse tomato and pepper houses that run hot and dry through summer, and for interior crops where humidity stays low. Cooler conditions slow reproduction; the vendor benchmark is a 24-hour average of at least 68°F for reliable establishment.
03
Crops, environments, and climate
Crops it supports
Vegetable crops
Tomato & pepper
Soft fruits
Ornamental crops
Poinsettia
Hemp / Cannabis
Environments
Greenhouses
Indoor facilities
Fields & row crops
Interiorscapes
Gardens
04
Storage
Release ERETforce™ on the day of arrival whenever possible. Pupae are most viable fresh; brief refrigeration is acceptable only if a same-day release isn’t possible. Don’t use product past its use-by date.
05
Instructions of use
Hanging cards & blister packs
Hang cards or blister packs on lower-canopy foliage near plants showing whitefly activity. Keep them out of direct sun and condensation drip; the parasitized scales need stable conditions while the adult wasps emerge over several days. Position cards every few plants in a hot spot; spread them more evenly across the crop for preventive releases. The adults exit on their own and disperse to find whitefly nymphs.
Loose pupae in vials
For the 30 ml vial format, sprinkle the pupae mixed with bran flakes lightly across the leaf surfaces of plants with whitefly pressure. Avoid clumping — even distribution gives the emerging wasps the best access to host nymphs. Don’t apply in direct sun; choose the cool part of the day.
Pull yellow sticky cards temporarily
Yellow sticky traps will catch adult Eretmocerus and pull them out of the canopy. Remove yellow cards before release and leave them down for the first few days. If you need to monitor for whitefly adults afterward, use blue cards for thrips, and run yellow cards for fungus gnats only two days a week — not continuously — while a population is establishing.
06
Monitoring & advisories
Monitor for
- Parasitized whitefly scales on the leaf underside turning gold-brown as the wasp develops. The developing larva remains partially visible inside — not fully concealed the way it is under Encarsia (which turns scales black).
- Light-brown pupal cases on the leaf underside — the final stage before adult emergence.
- Falling whitefly nymph counts on scouting routes 10–21 days after release. The first generation of new adult wasps emerges in roughly two to three weeks.
- Adult wasps in flight at sunrise and sunset around lower-canopy leaves where whitefly nymphs concentrate.
- Lower honeydew and reduced sooty-mold development as nymph populations drop.
Advisories
- Species match matters. For greenhouse whitefly (Trialeurodes vaporariorum), Encarsia formosa is the better fit. For Bemisia tabaci and related Bemisia spp., Eretmocerus is the right choice — the heat tolerance and ectoparasitism behavior favor it over Encarsia on tobacco-whitefly outbreaks.
- Ants defend whiteflies to protect honeydew. Control ants with barriers or boric-acid baits before release.
- Heavy honeydew can foul the wasps — they spend too much time cleaning themselves instead of parasitizing. Wash plants down at high pressure with soap and water before release if the crop is honeydew-saturated.
- For severe established outbreaks, knock adults down with a selective insecticide first, wait the residue out per the label, then release Eretmocerus into a manageable nymph population. Throwing the wasp at an outbreak alone won’t work fast enough.
- Some crops are “whitefly magnets” (poinsettia, tomato, cotton-family ornamentals) and need weekly releases instead of bi-weekly through peak pressure windows.
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Release rates — for conventional crops
| Classification | Rate | Interval |
|---|---|---|
| Preventive / low infestation preventive | 0.5–2 per 10 sq. ft. | Weekly to bi-weekly |
| Medium infestation active | 5–20 per 10 sq. ft. | Weekly until nymph counts drop |
| “Whitefly magnet” crops active | Same medium rate | Weekly through peak pressure |
| ERETforce™ ships as pupae on cards (5,000 / 10,000 / 15,000 per card), in blister packs (7,500 or 15,000), or loose in a 30 ml vial (10,000). Match the SKU to the canopy size and pressure level. | ||
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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.
08
Life cycle
The Eretmocerus eremicus life cycle runs egg → three larval stages → pupa → adult, with all immature development taking place on or inside the host whitefly nymph. Total immature development runs ~18 days under optimum conditions. Adults emerge from the leaf-underside pupal case to find new whitefly nymphs.
1
Egg
2
Larva
3
Pupa
4
Adult
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See it in action
Disclosures
Live-product policy. Beneficial Insectary works to guarantee the live delivery of fresh organisms. Replacements or credits are offered for compromised shipments when customers report issues or concerns within 24 hours — 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 methods, and other cultural, physical, or mechanical controls — can shift biocontrol-agent and pest populations. Long- or short-term establishment after release can’t be guaranteed, and refunds, discounts, or credits are not offered on products that have already been released.