Tag: Aphids

Aphidoletes Description

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 control aphids 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) in the summer.

Aphidoletes Usage

• Aphidoletes larvae are voracious and are better dealing with larger aphid colonies.
• They are generalist Aphid predators and attack many species of Aphids.
• It is best used from May to September.
• They cannot be stored, it needs to be used on the day of receipt.
• They are only suitable for use in a greenhouse or conservatory.
• 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. They prefer a relatively high humidity.
• They 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.
• Aphidoletes are harmless to children, pets and wildlife.

Aphid Control Products

Aphidius Description

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 as aphid pest control in greenhouses by commercial growers.

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 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, targeting 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 beneficials 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.
• Aphidius is harmless to children, pets and wildlife.

Aphid Control Products