A container of aphid wasps may contain very few visible wasps. Much of the shipment can be mummified aphids, with the adults still developing inside.
This is a fairly unusual delivery arrangement, but it makes sense once you know the life cycle. The mummy protects a developing parasitoid. Your job is to place it where the adult can emerge and reach the plants.
Unsure which aphid you have? The photographing an aphid guide explains what to capture before choosing a wasp.
Check the name before opening
Colemani, ervi and matricariae are not interchangeable. Confirm that the species or mixture fits the aphids you are treating. Broadly, colemani is commonly used for green peach and melon aphids, ervi for potato and foxglove aphids, and matricariae is an option for green peach aphid. Use a confirmed identification wherever possible.
This check matters more than perfect placement. No arrangement of little cups can give a wasp a suitable host if the aphid is the wrong species.
Use the unit printed for that species
FGMN’s current packages use two different units. Colemani is sold by plant coverage; ervi and matricariae use square footage. These are retailer treatment recommendations, not equivalent greenhouse rates or guarantees of control.
| Species | FGMN ordinary coverage | Worked example |
|---|---|---|
| Colemani | 4 per plant within the listed package coverage. | Ten plants: 40 colemani. A large specimen or dense infestation needs a coverage review. |
| Ervi | 1 per square foot; separate hotspot pack: 10 for 4 square feet. | Two planted 4-by-2-foot shelves: 16 ervi total for ordinary coverage. |
| Matricariae | 1 per square foot; separate hotspot pack: 10 for 4 square feet. | A 4-square-foot concentrated hotspot: the 10-count hotspot pack. |
For area-based releases, measure the planted shelf or bench footprint and add the areas of separate shelves. For a large, layered canopy, explain its size when arranging the rate. Do not switch between plants and square feet halfway through the calculation. 4
FGMN advises moving up a package size under heavy pressure. Treat leaves crowded with live aphids, fresh colonies on additional plants, and continued spread between checks as reasons to review that higher quantity. It is a retailer adjustment, not proof that every severe infestation will respond to one size up.
Keep the mummies protected and accessible
Release on arrival, in daylight. If adults are already present, open the container beside the affected foliage and let them leave without shaking them out. Put the remaining mummies and carrier in dry, sheltered release cups mounted near the canopy. Use stable cups that will not tip during watering. Divide a carrier-based shipment among separated plant groups; keep pre-attached mummy cards intact if that is your shipment format.
Keep the release out of direct sun and away from splashing water. Do not bury the mummies in potting mix or shut an opened release inside a sealed container. Leave the release point undisturbed for at least several days. At the one-week check, retain intact mummies and ask the supplier about the remaining emergence window before discarding the carrier; shipment age and temperature affect how long this takes. [2]
Match the canopy conditions
Koppert lists 68–77°F as most effective for colemani and ervi, and 59–77°F for matricariae. Excess heat reduces performance; a sunny canopy can be hotter than the room. Keep the mummies dry, but do not confuse dry carrier with a requirement for dry air. Move sticky traps away from the release points and foliage where the wasps are searching.
For pesticides, use the species-specific compatibility lookup with the exact active ingredient and application method. There is no dependable one-day waiting rule for all oils, soaps or other sprays.
If ants are tending the colonies, interrupt their access too. Otherwise they can defend the very aphids the wasps are trying to reach.
A release calendar with something to check
For an active infestation, arrange an initial series of weekly introductions and review progress each week. Published parasitoid programs commonly use repeated introductions rather than a single release; the exact quantity and length of the course depend on species, host match and pest pressure. Photograph the same colonies before each introduction. Three releases are a starting program to assess, not a promise that the third bottle finishes the job. 5
| When | What it means | Next action |
|---|---|---|
| Arrival | Adults may already be out; other wasps remain inside mummies. | Release immediately. Record whether shipped mummies already have holes. |
| First week | New holes in shipped mummies show emergence. | Keep the cups dry and open. If none appear, ask the supplier to assess the lot and conditions. |
| About 10–14 days after introduction | New mummies on plants are a useful expected sign under suitable conditions. | Compare living aphids too. No new mummies plus expanding aphids warrants checking host match and emergence now. |
| Each weekly review | Shrinking colonies suggest progress; expanding colonies need intervention. | Continue if improving. Reduce severe hotspots and reassess quantity or a complementary predator if worsening. |
The 10–14-day guide comes from Koppert’s product instructions. It is not a declaration that an earlier living aphid was never parasitized. 5
The bottle and the plant tell different stories
Holes in the shipped mummies tell you adults emerged from those mummies. New mummies on the plant tell you a later part of the process happened there. Neither observation alone proves that aphid numbers are declining.
Take a starting photograph of several colonies, then revisit them every few days. Watch for fresh mummies, fewer live aphids and fewer newly infested tips. Leave intact mummies on the foliage where possible. If the colony is still expanding, check host fit and conditions while continuing the advised release program.
Will these wasps sting or stay in my house?
These Aphidius wasps do not sting people and do not build social nests. Adults can fly around the room, so release near the plants rather than expecting them to stay inside one pot. Nectar or honeydew can support adult survival, but a new generation requires suitable aphids. They cannot continue multiplying on furniture, people or a pest-free houseplant. 6
A failed emergence check is a reason to contact the supplier, not to crush open every mummy. Send the delivery date, photographs showing intact and opened mummies, and the minimum and maximum temperature near the release. Preserve the remaining material while it is assessed.
You do not have to see the tiny wasp at work. You do have to see the aphids making less progress.
Sources and further reading
- Prado, Jandricic and Frank (2015). Ecological Interactions Affecting the Efficacy of Aphidius colemani in Greenhouse Crops. Insects 6, 538–575. Host suitability and factors affecting control.
- Cloyd (2024). Aphidius colemani and Aphidius ervi—Biological Control Agents of Aphids. Kansas State University MF3653. Extension guidance on life stages, release and emergence.
- Zamani et al. (2007). Effect of Temperature on Life History of Aphidius colemani and Aphidius matricariae, Two Parasitoids of Aphis gossypii and Myzus persicae. Environmental Entomology 36, 263–271. Constant-temperature laboratory study; development speed and mummification are different measures.
- FGMN Nursery. Colemani package coverage and release instructions; checked October 4, 2026. Area coverage also checked against the current ervi and matricariae listings.
- Koppert. Aphipar; see also Ervipar and Aphipar-M product guidance for emergence-to-mummy expectations and conditions.
- Evergreen Growers Supply. Aphidius species technical sheet. Non-stinging adults, shipment formats and repeated release programs.
- Additional current product instructions: FGMN ervi; FGMN matricariae; Ervipar; Aphipar-M.
