Aphidius ervi
A parasitoid wasp of about 3 mm — larger and darker than Aphidius colemani — sold for the big aphids that colemani does not control: potato aphid and foxglove (glasshouse potato) aphid. The female lays an egg inside the aphid, which swells into a leathery golden-brown mummy before a new wasp cuts its way out. Like colemani, it is released weekly while aphids are expected, not after they have taken over.
At a glance
- Mode
- Parasitoid — one egg per host
- Rate
- 0.25–2 /m² per release, weekly
- Ships as
- Mummies in buckwheat hulls
- Temp
- 20–25 °C best; active from 10 °C
- Pairs with
- Aphidoletes gall midge (Biobest)
- Setting
- Greenhouse and indoor crops
How it works
The female finds colonies by the smell of honeydew and the alarm signals of attacked plants, and Koppert describes her as more aggressive than colemani, chasing aphids to lay in them. Biobest puts one female's output at up to 350 aphids. Adults take only nectar and water. Size depends on the host: wasps reared on large aphids are much bigger than colemani, but ones reared on Myzus are the same size.
Inside the aphid the larva feeds, then pupates in the swollen skin, which hardens into a leathery golden-brown mummy; the adult leaves through a round hole at the rear, five to ten days after mummification. The whole cycle takes about 19 days at 21 °C (Buglogical). In alfalfa fields it is one of the two main parasites of pea aphid, though UC IPM notes the pink form of pea aphid partly resists it.
Is it established?
As with colemani, the mummy is the evidence. Check the stems and trusses where potato aphid sits, not only the leaf undersides.
- FIRST DAYSAdults emerging from the carrier; nothing yet visible on the aphids
- DAYS 10–14First large, leathery golden-brown mummies near the release points
- LATERMummies with a round exit hole at the rear — the next generation is out
- AFTERMummies spreading through the colonies; continue weekly while aphids are expected
Release & handling
Mummies arrive in a bottle of buckwheat hulls. Koppert says apply them straight away, or store for one to two days at 8–10 °C in the dark; Arbico says release within 18 hours but keep the box cool at 18–25 °C (65–77 °F) — the two suppliers disagree on holding temperature, so follow the one you bought from. Tip the carrier onto rockwool slabs or into release boxes, keep it dry and do not move it for a few days.
Release the same day
Adults start emerging soon after arrival. Get them into the crop.
Follow the label
Koppert: 8–10 °C, dark, 1–2 days. Arbico: 18–25 °C out of sun, within 18 hours.
Dry, undisturbed
On rockwool slabs or in release boxes near colonies, out of direct sun and irrigation.
Keep ants off
Arbico's release instructions say to protect the wasps from ants.
Pesticide sensitivity
UC IPM rates pyrethroids, acetamiprid and spinosad as highly harmful to parasitoids, azadirachtin as moderately to highly harmful, neem oil and soil-applied imidacloprid as moderately harmful, and insecticidal soap and narrow-range oil as low risk. Check a product →
When to choose something else
Aphidius ervi is the wasp for large aphids. Choose something else when:
- The aphid is green peach or melon aphid only — Aphidius colemani is sold for those and costs far less per wasp
- Colonies are already dense — add a predator such as the gall midge Aphidoletes aphidimyza on the hot spots; Buglogical says predators may be needed once infestations are established, and Biobest recommends the pairing
- The house runs above 30 °C — Koppert says it is not effective there
- You have small and large aphids together — suppliers sell colemani–ervi mixes
Where to buy
Suppliers listed alphabetically, not ranked. helpfulbugs takes no commission and does not sell insects.
- Arbico Organics250 / 500 / 1,000 / 5,000US
- Buglogical250 / 500 / 1,000US
- Koppert (Ervipar)250 / 500 / 5,000GLOBAL
- LS Systems (Erviline)250 / 500 / 2,000UK
Aphidius ervi by target
Rate and timing differ by what you are releasing it against. Each page below is the program for one pest.