Specialist · Aphids
Aphidius colemani
The best scout in the catalogue — a 2mm wasp that finds the first aphid colony before you do, and leaves a bronze mummy where it was.
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How much, and how often
Two questions — how bad it is, and how many plants. You get a size and the dates to put it out.
How bad is it?
Pick the one that sounds like your room. If you are between two, take the higher.
How many plants?
Six-inch pots. Count a large specimen with a dense canopy as three or four.
Your size and schedule
More about this dose
The three things people ask once they have their size. Open any of them.
Am I light, moderate or heavy?
Light
- A few aphids on one growing tip
- No honeydew yet, or one sticky leaf
- Nothing on the plants either side of it
Moderate
- Clusters on several stems and leaf undersides
- Sticky honeydew on the leaves below
- New growth coming in curled
- Aphids turning up on a second plant
Heavy
- Stems crowded end to end
- Sooty mould on the honeydew
- Winged aphids, which means they are leaving to start colonies elsewhere
- Ants running the stems
Colemani is at its best early, so if you are between two levels here the honest advice is to take the higher one and release sooner rather than bigger. An aphid colony doubles in under a week, and one release into a colony already running gets outrun.
Aphids reproduce without mating and give birth to live young that are already pregnant. A colony you judged as light on Monday is a different problem by Friday. Taking the higher level costs a little more once; taking the lower one usually costs you a second release two weeks later, by which point there is more to fix.
Why more than one round?
Putting it out
- Take yellow sticky cards down first. These wasps are drawn to yellow and the cards catch them very efficiently. A few days is enough.
- Release in the morning, in daylight. They need light to search and fly, and the start of a day gives them time to settle.
- Spread the material in the canopy, close to the aphids — or hang the open vial in a release box on a branch.
- Then leave it alone. Dry and undisturbed for several days while the wasps emerge. Tidying the material up mid-emergence ends the release.
- Leave the mummies on the leaves. Every bronze husk is the next wasp.
Everything else is optional. Get these four and the release has done what it can.
A cleaner way
On a display plant, tip small piles into bio-boxes or paper cups hung in the branches instead of dusting the foliage. Same dose, nothing visible on the leaf.
The failure is forgetting. Very few programs fail because the mite underperformed. They fail in week five, when the plants look fine, the reorder does not happen, and the population holding the line ages out with nothing behind it.
A schedule is the same decision, made once. A vial when it looks bad, then another when it looks bad again, is already a rhythm — just one you have to remember at the exact moment the plants look fine.
Change the size or the frequency, skip a box, pause or cancel from your account at any time.
Is this the right beneficial for your problem?
Five questions, in the order a grower actually asks them: what have you got, is this the answer to it, what will it eat, how does it do the killing, and will it survive your room.
Is this your pest?
Colemani is a specialist. It hunts small-bodied aphids and nothing else, and on those it is very hard to beat. If aphids are not what you have, the product you want is a different one.
Aphids cluster on stems and the undersides of new leaves, soft and pear-shaped, in greens and pinks and blacks. They leave sticky honeydew, and sooty mould follows it. New growth comes in curled and distorted, and the colony can double in under a week without anything arriving from outside.
Colemani is built for the small-bodied aphids — green peach and melon or cotton aphid above all. Larger species like potato and foxglove aphid are a job for ervi, its bigger cousin. Root aphids feed below the soil line, where it does not forage.
Then: is Colemani the right answer to it?
Choose this if
Choose Colemani when the aphids are small-bodied and scattered, and especially early. It is the best scout in the catalogue — a 2mm wasp that finds the first colony on a plant you had not thought to check, and kills it before you notice it was there. Each female parasitises hundreds of aphids, and every mummy she leaves behind hatches another wasp. It does not sting people or pets and there is nothing to spray.
Choose something else if
Large aphids are the limit — potato and foxglove need ervi. It needs at least twelve hours of light a day to stay active, and yellow sticky cards catch it very efficiently, so those come down around a release. And nothing about this survives a systemic insecticide, which moves into the aphid and kills the wasp developing inside it.
What it kills, and what it won't
Aphid mummies are not a second pest. A parasitised aphid hardens into a tan or gold husk glued to the leaf, and a week later a new wasp chews its way out. Those husks are the product working.
How it works
What it does to the pest, what it does on the plant, and what that leaves you looking at.
It lays inside the aphid
The female finds a live aphid and lays a single egg inside it. The larva develops in there and kills it from the inside, and the aphid hardens into a bronze mummy stuck to the leaf. No poison, no residue, no re-entry interval, and nothing for an aphid to become resistant to.
Every mummy is the next release
About a week later a new wasp chews a neat round exit hole and flies off to do the same thing. That is why a release keeps working after the adults you bought have gone — and why the one useful thing you can do is leave the mummies alone.
A scout, not a swarm
Its edge is low density. Colemani finds scattered aphids that a spray misses and a hungry predator cannot be bothered with, which is what makes it so good as an early or preventative release. The colony collapses gradually rather than overnight.
Give them sugar. Adults live two to three weeks with nectar or honeydew and considerably less without. Flowering plants nearby genuinely extend a release.
Will it work in your room?
Two things will undo a release. Yellow sticky cards catch these wasps very efficiently, so take them down for a few days. And a systemic insecticide moves into the aphid itself and kills the wasp developing inside — there is no way to run both.
About Aphidius colemani
A 2 to 3mm wasp that does not sting people and cannot be persuaded to eat anything except aphids. It has no interest in your plants, no interest in you, and a single job it does extremely well.
New to beneficials?
Five things that catch almost everyone the first time.
After you release it
What actually changes, how fast, and the one thing not to tidy up.
How you'll know it's working
Bronze mummies appearing on the leaves after about a week. That is the product working, not a new pest, and it is the clearest evidence any beneficial in this catalogue gives you.
Aphid numbers fall from there, because each mummy produces another wasp. The collapse is gradual rather than overnight, and the honeydew stops before the colony looks any smaller.
Leave the mummies alone. Each one on a leaf is an unhatched wasp. Wiping the leaves down loses that second generation, so this is the rare case where leaving things a bit untidy is the better call.
Getting it to you
What is in the vial, how it travels, and what happens if it arrives wrong.
What arrives
Mummies in a wood chip carrier — small tan aphid shells, each with a wasp finishing development inside. They are supposed to look inert.
Adults chew out over the following days and leave a neat round exit hole behind as your receipt. You may also find some have already emerged in transit, which is equally normal.
Release the morning it arrives. These wasps need daylight to search and fly, so the start of a day gives them time to settle and find the colonies. Adults have a very short life and cannot be stored.
When it ships, and when it lands
Shipping
We ship when they're ready to travel. Live orders go out Monday to Thursday. If a colony needs a beat to peak, or we're propagating a fresh batch, yours might hold up to a week. All mites and insects ship 2-day or Overnight depending on what's best for them.
When it lands
Open it that morning. Take yellow sticky cards down first. Spread the material out in the canopy near the aphids, or hang the open vial in a release box, and then leave it dry and undisturbed for several days while the wasps emerge. Tidying the material up mid-emergence ends the release.
About the ones that don't make it
Some of them die on the way. That is why we send more than you paid for.
A mummy is a hardened aphid the size of a pinhead, and it ships in a vial, in a van, for two days.
Roughly 15% will not survive that. We cannot prevent it, so we price it in: the number on the label gets counted out, and then the cushion goes in on top of it.
Your 100-wasp vial leaves here holding more than 100. The ones that do not make it are already paid for.
If you can see them
Ladybugs, lacewing larvae, Orius — the minute pirate bug — and the beetles. Tip a few onto white paper and give them twenty minutes at room temperature before you judge anybody.
Cold insects are genuinely good at playing dead. The deceased have been known to get up and walk off the counter.
Still more than about one in seven not moving? Photograph them and file a report.
The photo is not us doubting you. It is how we tell a bad batch from a bad courier day from a mailbox that hit 104°F.
If you can't see them
Mites, nematodes, eggs — and mummies, which is what this one ships as. A vial of tan husks looks the same whether the wasps inside are alive or not, and no photograph settles that. So we don't ask you to take one.
You file the report and our entomologist takes you through the diagnostic instead — the tap test on dark paper, where the box sat, what your room was doing, and then what the pest is doing about ten days later.
The exit holes are the real answer here. Give it a few days and look for small neat round holes in the husks — that is the release working, and it is worth checking before you file anything.
Seventy-two hours from delivery, either way, with your order number. Replacement or store credit, your pick.
What it does not reach
Three gaps this page has already named, and the beneficial that closes each one.
Potato and foxglove aphid need the larger wasp
Colemani is sized for green peach and melon aphid. Against the big, long-legged aphids — potato, foxglove — it is outmatched, and Aphidius ervi is the one built for them. If you are not sure which you have, the rule of thumb is body length: a green peach aphid is about 2mm, a potato aphid closer to 4.
Root aphids are below where this wasp forages
Being straight with you: the evidence for treating root aphids biologically is thinner than the labels across this industry suggest. Stratiolaelaps scimitus is the one agent with a published field trial against a root aphid, and that was one significant season out of two — worth trying, not a cure. Isolating new plants from established ones is the best-supported thing you can do.
Down for the release, back up to measure it
These wasps are drawn to yellow, and a card catches them as efficiently as it catches anything else — so take yours down for a few days around a release. Then put them back. Winged aphids on a yellow card are the early warning that a colony has started shipping out to other plants, which is exactly when you want to know.
Two cheap things that make the rest work harder. Blue cards give you the dated count this page keeps asking you to read. Breeder's Blend is pollen and Artemia; it keeps the population fed through the lull when prey gets scarce.
Questions
Do they sting humans?
No. Aphidius colemani are tiny parasitoids that only "sting" aphids to lay eggs. They are completely harmless to people and pets.
How do I know they are working?
Look for "mummies"—aphids that have turned into hard, tan, or gold-colored shells. This is proof that the wasps are breeding in your garden.
Can I use them with yellow sticky traps?
Use caution. Wasps are attracted to yellow traps. If you have a high wasp population, consider removing sticky traps for a few days during the initial release.
Can I use them with Neem Oil?
No. Neem and other oils will kill the wasps on contact. Stop all sprays 7 days before release. A synthetic pesticide is weeks, not days.
Do they work on Root Aphids?
No. Aphidius colemani hunts aphids on the foliage, and root aphids feed below the soil line where it does not forage. Honestly, the evidence for treating root aphids biologically is thinner than the labels across this industry suggest. The soil-dwelling mite Stratiolaelaps scimitus is the one agent with a published field trial against a root aphid, and that was one significant season out of two — worth trying, not a cure. Isolating new plants from established ones is the best-supported thing you can do.
How long do they live?
Adults live for about 7 to 14 days, but each female can parasitize hundreds of aphids during that time.