Aphidoletes aphidimyza
A small, long-legged gall midge whose orange larvae, up to 3 mm long, paralyse aphids with a toxic bite and suck them dry. It attacks more than 60 aphid species, including potato aphid, in which the common Aphidius colemani wasp cannot complete its development. It is released onto established colonies rather than preventively, needs humid conditions and moist soil to pupate in, and stops breeding when days drop below about 16 hours unless the house is lit at night.
At a glance
- Mode
- Predator — larvae only
- Rate
- 1–10 /m² per release, weekly
- Ships as
- Pupae in a bottle of carrier
- Temp
- 20–26 °C best (Biobest); 21–25 °C per US sheets; Koppert 20–30 °C
- Humidity
- High; suppliers say above 70 % RH
- Day length
- Diapauses under ~16 h without lights
How it works
The adults are delicate 2–3 mm midges that fly in the evening and at night and feed on pollen and honeydew rather than aphids. A female lays 150–200 tiny orange eggs, singly and only beside aphid colonies, over a life of one to two weeks. The eggs hatch in two to three days, and the legless orange larvae feed for about 3–10 days (supplier sheets differ), biting aphids at the leg joints, injecting a paralysing toxin and sucking out the contents. Estimates of the kill vary: Rincon-Vitova gives 3–50 aphids a day, Natural Enemies 4–65, Biobest 80–100 over the whole larval stage.
Fully fed larvae drop to the ground and spin a 2 mm silk cocoon in the top layer of moist soil or substrate; the cycle takes about three weeks at 21 °C (21–24 days by supplier). Shortening days trigger diapause in the cocoon — below 15.5 hours of light by UConn's figure, 16 by Rincon-Vitova's — so in most greenhouses it breeds only from about March to September. Rincon-Vitova reports that one 60 W bulb left on all night prevents diapause in more than half the larvae within a circle about 20 m across, provided nights stay above 15 °C.
Is it established?
There is no mummy to count. Look inside the colonies with a hand lens for the larvae and the collapsed aphids they leave.
- FIRST DAYSAdults emerging from the carrier at dusk; nothing visible on the plants yet
- WEEK 1Tiny orange eggs beside the colonies, then pale young larvae
- WEEK 2Bright orange larvae among the aphids; shrivelled, sucked-out aphid skins
- AFTERFewer live aphids in treated colonies; keep releasing weekly until control
Release & handling
Midges arrive as pupae in a bottle of carrier — vermiculite or wood fibre depending on the supplier. Koppert says apply immediately, or store for one to two days at 10–15 °C in the dark; Arbico says use within 18 hours. Do not scatter the contents: stand the opened bottle on the substrate or hang it in the crop, or put small piles onto moist growing media under the colonies, and leave it for about two weeks while the adults emerge.
Release the same day
Open at dusk if you can — the adults are active in the evening.
10–15 °C, dark
One to two days (Koppert). Other suppliers give different holding temperatures; follow your label.
On moist substrate
Under or beside the colonies, in shade, where the growing medium stays damp for pupation.
Leave it two weeks
Emergence is spread out; Rincon-Vitova expects it all within 14 days.
Pesticide sensitivity
Rincon-Vitova says insecticidal soap harms all stages and pirimicarb is slightly toxic and deters egg-laying. UC IPM's floriculture table rates acetamiprid and every pyrethroid it lists as high (medium to high) in harm to general predators. Check a product →
When to choose something else
The midge is a warm-season curative for aphid colonies. Choose something else when:
- It is autumn or winter and the house is not lit at night — the larvae diapause instead of breeding
- No aphids are present yet — midges lay only beside colonies; use a parasitoid wasp preventively
- There is no moist growing medium or soil under the crop for the larvae to pupate in
- The air is dry — suppliers want humidity above 70 %, especially for the pupae
Where to buy
Suppliers listed alphabetically, not ranked. helpfulbugs takes no commission and does not sell insects.
- Applied Bio-nomics250 / 1,000 / 3,000 / 5,000CA / US
- Arbico Organics1,000 / 2,000 / 10,000US
- Buglogical2,000 / 10,000US
- Koppert (Aphidend)1,000 / 10,000GLOBAL
Aphidoletes aphidimyza by target
Rate and timing differ by what you are releasing it against. Each page below is the program for one pest.