Aphid Pest Solution: Aphidius & Aphidoletes
Aphidius (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 Defenders Mixed Aphid Control (APH25) consists of 2 species, Aphidius ervi and Aphidius colemani, sold as just-hatching mummies. A. ervi attacks the commoner large species and A. colemani the common small species of aphid likely to be found inside.
Aphidius Life Cycle
One 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.
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 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 Eradicoat(TM) organic spray, targetting colonies before or after introducing Aphidius (leave a week after initial release). In this way colonies are reduced, allowing Aphidius to operate more efficiently on any survivors. Partially "Eradicoated" aphids also seem more susceptible to Aphidius attack.
- 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 Eradicoat 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 Eradicoat(TM) 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 and will not become a pest in its own right.
Aphidoletes (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 controlaphids in greenhouses .
Aphidoletes Life Cycle
Aphidoletes 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) under summer daylength.
- Aphidoletes larvae are voracious and are better dealing with larger aphid colonies.
- 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.
- If the floor in the area being treated is covered or solid, repeat introductions may be needed, as Aphidoletes needs soil/compost in which to pupate.
- Like all Defenders biological controls, Aphidoletes is harmless to children, pets and wildlife and will not become a pest in its own right.
Biological Aphid Control Product Details
Defenders supply Aphidius in tubes of 100 A. colemani plus 50 A. ervi and Aphidoletes in tubes of 250. Both products are simply released in the area to be treated.
Aphidius Aphid Control Mix
150 Aphidius mix is sufficient to treat an area of approx. 5 square metres of low aphid infestation.
ERA05, ERA10, ERA50
All packs of Aphidius & Aphidoletes are sent with complete instructions, and a free information sheet on Biological Aphid Control entitled "Your Questions Answered".
Remember! Biological controls are living creatures and can be effected by chemical usage. If you've used any persistent pesticides recently check with us before ordering Aphidius or Aphidoletes. As a general rule stop using pyrethrum 4 days before, derris 1-2 weeks before and soft soap insecticides 1 day before releasing Aphidius or Aphidoletes.