Aphidoletes aphidimyza — Predatory Midge for Aphid Control
How to Say It: af-ih-doh-LEE-teez af-id-ih-MY-zuh
One predator across a wide range of aphids.
Aphids rarely show up alone. One colony can turn into several within days, and different aphid species often share the same garden. Aphidoletes aphidimyza, or simply Aphidoletes,is a natural aphid control that works on more than 60 aphid species. This range makes it a good fit for vegetable gardens, ornamentals, fruit plantings and greenhouses where more than one aphid type is present.
Meet Aphidoletes
Aphidoletes is a tiny, delicate midge, a true fly and not a wasp, found naturally in North American gardens. Adults are about 2–3 mm long and mostly active at dusk, so you’re unlikely to see them. They feed on honeydew and don’t harm plants. These predatory midges come to you as pupae. Once adults emerge, they seek out aphid colonies on their own and lay their eggs right among the aphids. That puts the next generation of hungry larvae exactly where the problem is. The stage that controls aphids is the larva: a small, bright orange, legless maggot that grows to about 3 mm. Larvae feed for roughly one to two weeks. They then drop to the soil, spin a cocoon and pupate, and the cycle starts again.
One quirk about Aphidoletes is that females use a spider web, or something like it, to mate. Leaving existing webs in place helps, or you can stretch a few cotton balls thin near your plants as a stand-in.
Target Pests
- Green peach aphid
- Potato aphid
- Pea aphid
- Melon aphid
- Black bean aphid
- Rose aphid
- Lettuce aphid
- And many more other aphid species
How It Controls Pests
Adult females lay their eggs right inside aphid colonies. The larvae hatch in about 2–3 days and crawl through the colony. They paralyze each aphid with a toxin and then feed on its body fluids. A larva often kills more aphids than it eats, which adds to its impact during heavy infestations. Unlike parasitoid wasps, Aphidoletes doesn’t leave “mummies” behind. Aphids it has fed on simply shrivel and collapse.
When to Use It
Early in the infestation. Larvae need time to hatch and build up, so Aphidoletes works best at the first sign of aphids. Don’t wait for leaves to be coated in honeydew.
Spring through late summer. Shortening days and cool temperatures send larvae into a dormant state called diapause, during which they stop feeding. Outdoors, plan applications while days are long. In greenhouses and grow rooms, supplemental lighting can extend the season.
Late summer for next year. Applying in late summer, while aphids are still present, reduces the aphids that overwinter. It also sets up a predator population that becomes active again in early spring.
Hydroponics. Larvae need soil or another moist medium to pupate in. In hydroponic setups they’ll still feed on aphids but won’t establish a lasting population, so plan on repeat applications.
Application Rates
A bottle of 250 Aphidoletes pupae will cover approximately 2,500–5,000 sq. ft. at light or moderate pressure.
| Infestation | Rate | Frequency |
| Light | 1 per 20 sq. ft. | Weekly, 2–3 times |
| Moderate | 1 per 10 sq. ft. | Weekly, 2–3 times |
| Heavy | 1 per 3–5 sq. ft. | Weekly, 2–3 times |
| Field crops | 2,000–4,000 per acre | Weekly, 2–3 times |
These are general starting points — actual application should be adjusted based on pest pressure/species, plant type, and infestation severity.
Temperature & Humidity
Temperature: 50–88°F
Humidity: Pupae and pupating larvae need moist soil or media. The soil around the application spot should stay damp but not waterlogged.
Application Instructions
- Open the container next to the infested plants. Gently shake any adults that have already emerged onto the leaves.
- Spread the remaining pupae in small piles on moist soil near aphid colonies, out of direct sun.
Lay the open container on its side nearby and leave it for about 3 days so late emergers can get out. - Don’t let the pupae material dry out. Adults may not emerge from dry media.
- Take yellow sticky cards down for the first few days, because they trap adult midges. Blue cards can stay up, but keep them away from the application spot.
- Use a 10x hand lens to check progress. Full-grown larvae are easy to spot among aphids by their orange color. Young larvae are pale and much harder to see.
Pairing for Broader Aphid Control
Aphidoletes pairs well with our aphid parasitoid wasps sold individually or in the Aphid Double Mix and Aphid Triple Mix.
- Aphidius colemani - small-bodied aphids
- Aphidius ervi - large-bodied aphids
- Aphelinus abdominalis - small and large-bodied aphids
A bonus of this pairing is that you can tell who’s working. Mummified aphids come from the wasps, and collapsed, shriveled aphids point to Aphidoletes.
Avoid using Aphidoletes on the same plants as green lacewings or Amblyseius swirskii. Lacewing larvae eat Aphidoletes larvae, and A. swirskii may eat their eggs.
Sustainable Pest Management
- Biological aphid control that works alongside other IPM methods
- No mixing or spraying required
- Works in gardens, greenhouses and grow rooms
- Pairs with other natural enemies for broader control
Pro Tips
- Control ants first. Ants guard aphid colonies for their honeydew and will drive predators off.
- Monitor both aphids and larvae weekly so you can time follow-up applications.
- Keep insecticide sprays away from areas where larvae are feeding.
Storage
Put Aphidoletes out as soon as possible. Pupae that haven’t started emerging can be held at 50–59°F, out of direct sunlight, with the media kept moist. Emergence can take up to 5 days. Once adults appear, get them onto your plants right away.
FAQs
How many Aphidoletes do I need for my garden?
For light infestations, start with 1 per 20 sq. ft. For moderate, 1 per 10 sq. ft., once a week for 2–3 weeks. Heavier infestations or fast-spreading aphids may need more at hot spots, or an added aphid parasitoid.
Why can’t I see them after I put them out?
Adults are small and mostly active at dusk, and young larvae are pale and tiny. Check aphid colonies with a hand lens about a week after application. Look for orange larvae and shriveled, collapsed aphids.
Can I use Aphidoletes indoors?
Yes, as long as the plants get long days, either naturally or from grow lights, and the soil stays moist enough for larvae to pupate. Short days trigger dormancy.
How is Aphidoletes different from aphid parasitoid wasps?
Parasitoid wasps lay an egg inside each aphid and leave a mummy behind. Aphidoletes larvae feed on aphids directly and work through whole colonies. The two approaches complement each other well.
Can I use neem oil or insecticidal soap with Aphidoletes?
Contact sprays can harm larvae and emerging adults. If you need to spot-treat, do it before you put Aphidoletes out, and avoid spraying where larvae are feeding.
Will they come back next year?
Outdoors, larvae from late-season generations overwinter in cocoons in the soil and become active again in spring, as long as aphids are around to feed them.