Aphidoletes Needs an Exit

You open the container and see carrier material. No dramatic movement. No tiny cavalry forming ranks.

Aphidoletes commonly arrives as pupae, so stillness is expected. The adult midges have to emerge before they can find aphids and lay the eggs that become hunting larvae. Your first job is to give them a good place to emerge.

Put the release point near the problem

For FGMN’s pupae in carrier, set the open bottle low beside the affected plants, in shade on damp potting mix. The damp mix is beneath the bottle; do not pour water into the bottle. Release on arrival; dusk or low light suits the adults’ evening activity. Keep the carrier in the bottle, with a clear exit. Do not shake it over the leaves, flood it, or seal it inside a bag. Keep it away from direct sun, heaters, fan blasts and watering splash.

Sheltered emergence pointPupation habitat beneath plants

On one or two plants, a nearby sheltered position is enough to work with. You do not need to place one pupa beside every aphid. In glasshouse research, adults emerged successfully from open bottles of carrier; the authors also observed eggs on plants well away from the release point. That supports letting the adult do the searching, without promising a particular flight distance in your home. [3]

Check the place where the insects will live

Measure temperature and humidity beside the plants, including after the lights go off. A practical target is about 68–79°F around the foliage and relative humidity above 70%; egg laying becomes restricted around 59°F and below. The peer-reviewed review identifies warmth, humidity, mating sites and pupation sites as separate requirements. Warm daytime air does not compensate for a cold night. 1

A damp pot is not proof of humid air. Conversely, do not keep roots saturated just to help an insect: maintain appropriate plant watering and choose a sheltered emergence location. A dry open living room may be a poor fit even when its daytime temperature looks right.

Mature larvae later need a pupation site. Slightly moist potting mix beneath the canopy may provide one; a dry shelf does not. Short days can also send the next generation into dormancy. For a winter release, check the actual light schedule with the supplier before relying on establishment. Continuous bright lighting is not a substitute for a suitable day–night cycle. Repeat releases can replace a missing second generation; they cannot fix conditions that prevent the first adults from laying eggs.

Measure the plant area before choosing a quantity

FGMN’s current package coverage is area-based: 16 midges for 16 square feet, 50 for 50 square feet, or 100 for 100 square feet. The separate hotspot package contains 10 for a 4-square-foot patch. These are FGMN package recommendations, not a universal rate established by a houseplant trial. 4

For example, a planted shelf 4 feet long and 2 feet deep occupies 8 square feet. Two such shelves total 16 square feet. Include the affected plant area on both shelves; do not count an entire empty room or just the small circles of potting mix. If two groups are separated, arrange an emergence point near each, using separately supplied containers or an approved release-box method rather than scattering the pupae.

A few localized colonies fit the ordinary coverage calculation. Aphids covering multiple new leaves, spreading to additional plants, or returning between checks indicate heavier pressure. Use the hotspot option for a localized 4-square-foot patch and ask for a treatment rate for a larger severe outbreak; do not extrapolate a tiny hotspot pack across an entire room.

The first evening is not the whole treatment

First come adults, then eggs, then feeding larvae. The exact pace depends on the shipment's development and the conditions around it. Begin checking after release, but do not judge the entire treatment by whether adults are flying around in daylight.

Adult emergesEggs beside aphidsLarvae feed

Take a quick photograph of a few infested growing tips and leaf undersides when releasing; do not hold the shipment to collect a baseline. Return to those same places every few days. Look for orange larvae and changes in live aphid numbers; a comparable view tells you more than trying to remember whether Tuesday looked worse.

Book the next check as well as the next release

For an active aphid infestation, we recommend repeat releases every 7 days until control is established. Each weekly release uses a fresh shipment; do not hold back part of the original bottle for later weeks. Compare the same colonies twice a week and review the whole treatment at each weekly release: are larvae present, are live aphids declining, and are new colonies appearing? If the infestation is expanding, change the conditions, coverage or treatment choice now. Repeating an unsuitable release is not a plan.

You can pause repeat releases when successive checks show the existing colonies continuing to shrink and no new colonies appearing on fresh growth. Keep checking after you pause, and resume weekly releases if colonies begin expanding again. A few orange larvae show that predators are active; they do not, by themselves, tell you the aphids are under control.

Keep the emergence bottle in its protected position during the first week. Check the opening and inner wall briefly each day without shaking out the carrier. If you see no adults or larvae by that review, send the supplier the delivery date, a bottle photograph, and your day/night temperature and humidity readings. This is a practical troubleshooting checkpoint, not a test proving the pupae are dead. The results guide separates emergence from feeding.

Move exposed sticky cards away from the release and active colonies so they do not intercept the emerging adults. Check the exact pesticide product in a beneficial-organism compatibility database; a dry spray residue is not automatically harmless. High densities of generalist predatory mites can also eat midge eggs, so tell your supplier if you are already using swirskii. More beneficials does not always mean more of every beneficial.

Interrupt ant access before release if ants are tending the colonies. Otherwise, you are placing the predator beside the aphids’ security detail.

The bottle is the departure lounge. Keep it usable long enough for the passengers to leave.

Sources and further reading

1. Boulanger et al. (2019). Optimizing aphid biocontrol with the predator Aphidoletes aphidimyza, based on biology and ecology. Pest Management Science 75, 1479–1493. Review of establishment, mating, climate and diapause.
2. Cornell University. Aphidoletes aphidimyza. Extension guide to appearance, feeding and life stages; practical guidance supplementing the peer-reviewed research.
3. Van Schelt and Mulder (2000). Improved methods of testing and release of Aphidoletes aphidimyza for aphid control in glasshouses. European Journal of Entomology 97, 511–515.
4. FGMN Nursery. Current package counts, coverage and shipment format. Checked October 4, 2026; retailer guidance.