Aphidius ervi — Parasitic Wasp for Potato, Foxglove & Pea Aphids
How to Say It: uh-FID-ee-us ER-vye
Built for the big aphids that smaller parasites pass over.
Potato and foxglove aphids are large, fast-feeding aphids that can yellow and twist leaves even before their numbers look serious. Most aphid parasites are too small to handle them well. Aphidius ervi is the larger wasp that takes them on, turning them into golden mummies from the inside out.
What They Are
A. ervi is a parasitoid wasp, closely related to Aphidius colemani but bigger, and it specializes in large-bodied aphids. Despite looking like a tiny, delicate fly, it is a determined hunter. Females search plant by plant and lay their eggs inside the aphids they find.
Aphids It Targets
Primary:
- Potato aphid
- Foxglove aphid
- Pea aphid
Secondary:
- Rose aphid
- Other large-bodied aphid species
How It Works
The female wasp lays one egg inside each aphid she finds. As the larva grows, it consumes the aphid from within. The aphid’s body then swells and hardens into a golden mummy, and the young wasp pupates inside it. When it’s ready, the new adult cuts a round lid in the back of the mummy and goes looking for more aphids to parasitize.
When to Use
Bring in A. ervi when you see large aphids, or as a preventive in crops that tend to attract them: peppers, eggplant, tomatoes, potatoes, and roses. It stays active in cooler conditions than many aphid parasites, which makes it useful in spring and fall.
NOTE: short day lengths can send it into dormancy, so activity may slow in late fall and winter. For winter aphid control under short days, A. colemani is the better choice for small aphids.
Application Rates
| Aphid pressure | Rate | How often |
| Preventive or light | 1 per 10 sq. ft. | Weekly, 2–3 applications |
| Moderate | 2–3 per 10 sq. ft. | Weekly, 2–3 applications |
| Heavy or hot spots | Up to 5 per 10 sq. ft. | Weekly, 2–3 applications |
These are general starting points — actual application should be adjusted based on pest pressure/species, plant type, and infestation severity.
Temperature & Humidity Range
Temperature: 50°F to 86°F
Humidity: 60–80% relative humidity
How to Apply
- Gently sprinkle the mummies onto leaves of affected plants, or into a hanging release box. Never put them on the soil.
- Set the open container on its side among the plants for 24 hours so the last wasps can make their way out.
- Keep the mummies dry and undisturbed for a few days.
- Take down yellow sticky traps for the first few days so they don’t catch the wasps.
Signs It’s Working
Within 10–14 days, look for golden mummies on the leaves. A neat, round hole in the back means a new adult has emerged and joined the hunt. Control is typically achieved once about 80% of the aphids are parasitized.
Black mummies point to aphid parasitism by Aphelinus abdominalis instead.”
Pairing for Broader Aphid Control
A. ervi covers the big aphids.
- If you also have small ones, like green peach or melon aphids, add A. colemani.
- For a heavy outbreak, add Aphidoletes aphidimyza, a predator that feeds directly on aphids.
Not sure which aphids you have? The Aphid Double Mix pairs A. ervi with A. colemani. The Aphid Triple Mix adds Aphelinus abdominalis for the widest coverage.
Safe, Sustainable Pest Management
- 100% natural biological control agent
- Safe to use around people and pets
- Safe for vegetables, fruit, and other edible crops
- Fits into any integrated pest management (IPM) program
- No protective gear needed
Storage & Handling
Use your order as soon as it arrives. If you need to wait, keep it at room temperature, never refrigerated, and out of direct sunlight until the wasps begin to emerge.
FAQs
How many Aphidius ervi do I need?
Start with 1 wasp per 10 sq. ft. each week for prevention or light pressure, and go up to 5 per 10 sq. ft. for active colonies. Most growers apply weekly for 2–3 weeks.
How do I know if I need A. ervi or A. colemani?
Look at the size of your aphids. Big ones, like potato, foxglove and pea aphids, call for A. ervi. Small ones, like green peach and melon aphids, call for A. colemani. Have both, or not sure? The Aphid Double Mix covers both.
Why does A. ervi slow down in winter?
Short days can trigger a dormant phase, so it may be less active from late fall into winter. A. colemani doesn’t respond to day length the same way, so it’s the go-to for small aphids under short days.
Will these wasps sting people or pets?
No. They’re only a few millimeters long and only interested in aphids.
Can I spray neem oil or insecticidal soap while using A. ervi?
Not on the plants where the wasps are working. Sprays can kill adult wasps and the young developing inside the mummies. If you’ve used a long-lasting broad-spectrum insecticide, wait at least four weeks before adding Aphidius.
What do jagged holes in mummies mean?
A hyperparasitoid, a tiny wasp that attacks Aphidius inside the aphid, has emerged. A few are normal. If you see many, add Aphidoletes aphidimyza, which hyperparasitoids don’t affect.