Aphid Pest Solution: Aphidius & Aphidoletes

Aphidius Description

AphidiusAphidius (Pronounced: AY-FID-EE-USS) is a small slender winged parasitic wasp about 2mm long and black in colour. The female lays single eggs into immature aphids (greenfly or blackfly).

A parasitised aphid appears swollen & "mummified", ranging in colour from gold or bronze to brown or black.

Aphidius is widely used to control aphids in greenhouses by commercial growers.

The Aphid Control (APH500) consists of 500 Aphidius colmani sold as just-hatching mummies. 

Aphidius Life Cycle

Aphidius Life CycleOne female Aphidius lays up to 100 eggs in her lifetime. Eggs are laid into immature aphids.

After the Aphidius egg hatches, the larva develops inside the growing aphid, eventually killing it. The parasitised aphid then takes on a mummified appearance. (see left)

The parasite fixes the dead aphid to the leaf with a silk thread. Then the Aphidius larva spins a cocoon inside the aphid, from which it finally emerges as an adult wasp. A circular emergence hole can be seen in the back of the aphid.

The complete life cycle takes about 3 weeks at 20ºC (68ºF).

Aphidius Usage

  • Aphidius is ideally introduced as soon as single aphids are seen on the plants. It works much better on small, isolated patches of aphids, rather than large colonies.
  • Once established, large aphid populations can be hard to get rid of.  Use SB Plant Invigorator organic spray, targetting colonies before introducing Aphidius (which can be released as soon as the SB treated leaves are dry).   In this way colonies are reduced, allowing Aphidius to operate more efficiently on any survivors.  However SB should NOT be used once the benficials have been released
  • Aphidius is a strong flier. Ideally, vents and/or doors near plants being treated need to be closed or netted over to prevent Aphidius from escaping.
  • Aphidius is more efficient on some plants than others, and seems to prefer non-hairy leaves.
  • Aphidius is only recommended for use in a greenhouse or conservatory.  In the garden, naturally occurring Aphidius and other parasites and predators will usually appear spontaneously.  Spraying colonies with SB Plant invigorator  organic spray will often help this natural process.  Beware not to use toxic chemical pesticides in the same way.  The opposite effect may be achieved, as aphids become resistant and natural beneficials are killed.
  • A minimum temperature of 10ºC (50ºF) is required. At lower temperatures, use SB Plant invigorator to keep numbers down until Aphidius can be introduced.
  • A temperature of 18ºC (64ºF) is desirable for at least a couple of hours a day to allow the parasites to be at their most active.
  • Aphidius cannot be stored, it needs to be used on the day of receipt.
  • You will know when Aphidius is working as you will be able to see parasitised or "mummified" aphids on the leaves.
  • Like all Defenders biological controls, Aphidius is harmless to children, pets and wildlife.

Aphidoletes Description

AphidoletesAphidoletes (Pronounced AY-FID-O-LEE-TEES) is a small midge, 2mm long and slender with long legs. Males have long, grey, "feathered" antennae and females have more simple antennae.

Most often seen are the larvae, which are maggot-like and about 3mm long when fully grown. They are yellow-orange to orange-red in colour and can be seen in aphid colonies.

Aphidoletes is used by commercial growers, usually in combination with Aphidius, to control aphids in greenhouses .

Aphidoletes Life Cycle

Aphidoletes Life CycleAphidoletes adults feed on aphid honeydew and are active at dusk and during the night. During the day they rest hanging in cobwebs in dark corners.  The bright orange-red eggs are laid among or near to aphid colonies.  Females lay up to 100 eggs in their lifetime (about a week).

After 2 to 3 days, eggs hatch into minute larvae. They are voracious predators and will kill and eat many aphids until fully grown just a week after hatching.  Even a small larva can paralyse and feed from a fully-grown aphid.

When fully grown the larvae fall to the ground, burrow into the soil and spin cocoons that they reinforce with particles of soil. After a few days the larva begins to pupate.

In day length less than 15 hours, larvae do not pupate.  Instead they go into "suspended animation", until day length increases, at which time they re-awaken to complete development into Aphidoletes adults.

The complete life cycle takes about 3 weeks at 20ºC (68ºF) in the summer.

Aphidoletes Usage

  • Aphidoletes larvae are voracious and are better dealing with larger aphid colonies.
  • Aphidoletes are generalist Aphid predators and attack many species of Aphids.
  • Aphidoletes is best used from May to September.
  • Aphidoletes cannot be stored, it needs to be used on the day of receipt.
  • Aphidoletes is only suitable for use in a greenhouse or conservatory.
  • Aphidoletes adults need a minimum night time temperature of 15ºC (60ºF) for egg laying. However, a temperature of 18ºC (64ºF) is desirable for at least a couple of hours a day. Aphidoletes prefer a relatively high humidity.
  • Aphidoletes needs soil/compost in which to pupate. If the plants being treated are on a concrete floor, they will not be able to complete their life cycle so repeat introductions may be needed.
  • Like all Defenders biological controls, Aphidoletes is harmless to children, pets and wildlife.

Biological Aphid Control Product Details


Product Name

Product Code

Area Treated

Aphidius colemani  Aphid parasites


 A, colemani is sufficient to treat an area of approx. 20 square metres of low aphid infestation.

Aphidoletes - Aphid predators


Aphidoletes is sufficient to treat an area of approx. 20 square metres of high aphid infestation.

Aphidoletes -Aphid predators


Aphidoletes is sufficient to treat an area of approx. 40 square metres of high aphid infestation. 

All packs of Aphidius & Aphidoletes are sent with full release instructions contained in the document wallet on the package.

Remember! Biological controls are living creatures and can be effected by chemical usage. If you've used any pesticides recently check with us before ordering Aphidius or Aphidoletes as it may not be possible to use them.For heavy infestations of Aphids, to spot treat a small outbreak, or if it is too cold, you can use SB Plant Invigorator, an organic spray. This will target colonies and reduce the population. The beneficials can be released as soon as the SB treated leaves are dry but it should not be used after their release.