Small aphids clustered on the new growth — green peach and melon aphid above all. Aphidius colemani is a parasitic wasp about the size of a fungus gnat, with an unreasonable talent for finding a single aphid in a full canopy. It has no sting, no interest in you or your kitchen, and it searches efficiently at low density — exactly where sprays and predators both do worst.
It is also the least work of anything we sell. Nothing to mix, nothing to spray, no residue and no re-entry interval — you open the vial near the plants and the wasps do the finding themselves. They reach aphids tucked into growing tips and leaf undersides a spray would never wet, they keep working at densities too low for you to even see, and aphids cannot develop resistance to being parasitised. Safe around people, pets and anything you plan to eat.
What you will see is not dead aphids. The female lays one egg inside an aphid; a week or so later that aphid becomes a hard, swollen tan shell glued to the leaf — a mummy — with a neat round hole where the new wasp chewed its way out. Count mummies, not activity.
Best for: Small, scattered, early aphid colonies — green peach or melon aphid.
How many: Sizes go by plant count. Under heavy pressure take one size up, and plan a second release 7–14 days later.
Arrives as: Mummies, or already-hatched adults. Small gold-tan shells mean the wasps are either still inside or already out hunting.
Speed: Mummies at 7–12 days; the next generation of adults 4–6 days after that.
Safe around: People, pets, plants and food crops.
Not for: Potato aphid or foxglove aphid, the big pale-green and pink ones — colemani will sting them but cannot develop inside them, so Aphidius ervi is the one there. No thrips, whitefly, mites, mealybug, scale or fungus gnats.
Field Notes
Aphidius colemani
The beneficial
Species
Aphidius colemani
Common name
Aphid parasitoid
Type
Parasitic wasp — endoparasitoid
Size
2–3mm. Small dark wasp, narrow-waisted. Does not sting people
What does the killing
Successful parasitism, and only that. Aphids do drop off leaves and pause feeding while a female works a colony, but field trials show that disturbance alone does not reduce the population. Count mummies, not activity
How it works
Female lays a single egg inside a live aphid. The larva develops internally, kills the host, and the aphid hardens into a papery bronze mummy glued to the leaf. A new wasp chews out roughly a week later
Egg to adult
Roughly 2 weeks at 70°F; mummies appear in about a week
Adult lifespan
2–3 weeks with a sugar source, considerably less without
What it eats
Hunts
Small-bodied aphids — green peach aphid (Myzus persicae) and cotton/melon aphid (Aphis gossypii) above all, plus other Aphis and Myzus species
Best against
Small, scattered, early aphid colonies. Searches efficiently at low density, where sprays and predators both do worst
Also eats
Nectar and honeydew — adults need a sugar source. Flowering plants nearby extend adult lifespan
Eats opportunistically
Nothing else. No alternate host outside aphids
Won't touch
Thrips, whitefly, mites, mealybugs, scale, fungus gnats. Potato aphid and foxglove aphid — it will sting them, but it cannot develop inside them, so the aphid survives and keeps reproducing. Use Aphidius ervi for those two
What arrives
Where it works
Humidity
50–80% RH. No high-humidity requirement
Light
Needs daylight to search and fly
Establishes
Yes, while aphids are present. Population collapses when hosts run out
Running it
Deploy
Immediately on arrival. Open the container in the canopy — hang mummy cards in shade if that's the format
Release timing
Morning, in daylight. Repeat weekly while aphids are active
Compatible with
Predatory mites, Stratiolaelaps scimitus, beneficial nematodes, lacewings, ladybugs, springtails, Diglyphus, other Aphidius species
Keep separate from
Broad-spectrum and systemic insecticides — systemics move into the aphid and kill the developing wasp. Yellow sticky cards will catch adults; pull them at release
Chemical interval
One day after neem oil or insecticidal soap. Never with sulfur, at any dilution
Safe around
Pets, children, plants
