This type of hymenopter is the most used and versatile aphid parasitoid worldwide. Despite its vast range, it is particularly efficient against Aphis gossypii and Myzus persicae, so it is used a lot in biological control, and especially for strawberries, peppers, aubergines and cucurbitaceae.
Adults are small wasps, 2-3 millimetres long with black bodies and antennas almost as long as their entire bodies. Females look for aphids and, when they find their victim, the bend their abdomen forwards and deposit an egg inside of the aphid's body. The latter is not killed, but continues to live and even eats more.
Inside the aphid though, the larva continues to grow and, in a few days, it devours the body of the aphid entirely and pupates. The body of the aphid swells and turns brown, until it becomes a so-called mummy (in the photo below).Ten days after it has been laid, a new adult Aphidius emerges from the body of the aphid through a hole in the rear part.
As with all parasitoids, the Aphidius colemani has a very good research capability, so it is ideal for preventive use. In fact, as aphids are particularly dangerous, a prompt introduction is advisable. It is possible to introduce few parasitoids, but they must be introduced repeatedly for a number of weeks in a row, so a parasitoid/guest balance can be reached before aphids cause too much damage.
Depending on the case, the total introduction should be of 2 to 6 parasitoids per square metre.
Aphidius colemani are supplied as pre-parasitized aphids in practical packs, and it is possible that some adults are already in there when launched. Just introduce the adults, if any, and distribute the mummies on leaves or using small containers.