Aphidius colemani is a slender, black insect with brown legs, long antennae and conspicuous wing venation. Its size depends on the size of the parasitized aphid, but is usually about 2 mm. The female has a pointed abdomen, while the male's abdomen is round-shaped. The female Aphidius deposits an egg in an aphid. She bends her abdomen under her legs and injects an egg in the aphid with her ovipositor. This takes only a fraction of a second.

The wasp parasitizes adults and nymphs. During the egg stage of the wasp (the first 3 days after parasitation), the aphid even eats more than normal and secretes more honeydew. Parasitized aphid adults or 4th instars keep on producing progeny.

Then, the Aphidius larva starts eating the aphid from inside, starting with the non-vital parts. Seven days after parasitation (at 21°C or 70°F) it fixes the aphid onto the leaf, and forms a silken cocoon which makes the aphid swell. The outside of the aphid becomes brown and leather-like, and is then called a mummy. Four days after the beginning of the mummification (at 21°C or 70°F) an adult Aphidius leaves the mummy through a round hole.

The total development of Aphidius colemani takes 14 days at 21°C (70°F), which is longer than aphid development in optimal circumstances (9 days). However, this is largely compensated by the hundreds of eggs Aphidius lays. The main part of these eggs is laid during the first 4 days. An adult Aphidius lives for 2-3 weeks.

The parasitic wasp finds aphid colonies from a long distance by "alarm signals" produced by an infected plant. At shorter distance it smells the honeydew. The adult Aphidius feeds on honeydew. In the presence of an Aphidius in an aphid colony, aphids often secrete 'alarm pheromones'. The other aphids start to panic, and often let themselves fall down, and usually die on the ground.

Male Aphidius emerge from unfertilized eggs. These are deposited soon after mating or at the end of the female's life. The ratio females-males is usually about 2:1.

The life cycle of Aphidius ervi resembles Aphidius colemani very much, but their hosts are different. For more information concerning the biology of A. ervi check Ervi-M-System.

Several wasp species parasitize Aphidius larvae or pupae. A hyperparasite deposits an egg in the larva or young pupa of Aphidius. After hyperparasitation, the mummy stage takes place a few days longer than the usual four days for a non-parasitized Aphidius. Hyperparasites leave the mummy through a hole with a jagged edge, and not through a round hole as Aphidius does. Aphidius also usually leaves the lid of the exit hole attached to the mummy.

Aphidius-Mix-System can be released on all crops on which the compatible hosts occur. In view of the fast reproduction of aphids, they have to be controlled early. These parasitic wasps are very suited for preventative control. In several greenhouse crops, such as sweet pepper, cucumber, eggplant, rose and chrysanthemum, preventative weekly introductions of minimally 0.15 Aphidius/m² are recommended.

As soon as aphids are detected on sticky plates (BUG-SCAN^®) or on the plants, quantities are increased to 0.5-1 Aphidius/m²/week, depending on the crop and the situation, for at least 3 weeks.

In the case of a curative treatment often the gall midge Aphidoletes aphidimyza is released simultaneously. Further developed infestation are tackled with the ladybird Adalia bipunctata. From summer on, aphid control with Aphidius colemani can be hampered by hyperparasites.
 

Aphidius-Mix-System is delivered in a bottle of 500 Aphidius colemani and 250 Aphidius ervi mummies with buckwheat as carrier. The mummies are sprinkled in Bio-Boxes that are hung in the crop.
Aphidius-Mix-System can be stored briefly at 6-8°C and RH >85%.

• Aphidius-Mix has to be introduced preventatively for good aphid control.
• Aphidius colemani is very efficient for the biological control of the cotton aphid (Aphis gossypii) and the green peach aphid (Myzus persicae).
• Aphidius ervi is effective for the biological control of potato aphid (Macrosiphum euphorbiae) and glasshouse potato aphid (Aulacorthum solani).
• As soon as aphids are spotted, introduce larger quantities of Aphidius colemani and Aphidius ervi in combination with the Aphidoletes-System. Consult the Biobest introduction scheme concerning the amount of Aphidius colemani to be introduced.
• Sprinkle the mummies in pots which are hung in the vegetation or on a cut leaf hung in the plants. Some days after the introduction the mummies will hatch. The first parasitized aphids (mummies) can be spotted about 2 weeks later.

NB Aphidius colemani and Aphidius ervi are sensitive to several pesticides.Be careful when using pesticides to control other pests and diseases. Always check the Biobest side effects manual.

• With the combined introduction of these 2 parasitic wasps one controls a whole range of aphids.
• Applicable in many crops.
• Also controls well the cotton aphid and "red aphid".
• Preventative introduction possible.
• Good searching ability.
• High number of eggs per female.
• Parasitation is easy to recognize (mummies).
• Population maintains also at low infestations.