Aphipar - Aphidius Colemani

What is it?

APHIPAR is the trade name used by Zonda Resources and Koppert Biological Systems for the parasitic wasp Aphidius colemani .  APHIPAR is used to control various aphid species in a range of crops. 

Adult wasps may vary in size from 0.5 to 1cm in length depending on the size of their hosts.  The male has longer antennae, and a rounded shaped end to his abdomen.  Females have a more pointed abdomen, and an ovipositor.  Adults are usually dark brown to black in colour.

What does it do?

The parasitic wasps (APHIPAR) actively search out and parasitise adult and juvenile green peach aphids (Myzus persicae) and adult and juvenile cotton or melon aphids (Aphis gossypii).  The adult female wasp lays an egg inside an aphid.  Four larval stages occur in aphids.  Before the larva finishes developing, it spins a cocoon in the aphid.  A parasitised aphid swells because of this, and stiffens into a leathery brown, mummy-like wrapping.   

These are referred to as mummies.  The adult wasp leaves the aphid body through a small round hole cut in the rear of the mummy. 

Aphids do not die immediately after being parasitised. Parasitised adults can still produce a few offspring, unless they are parasitised at an early stage.  Winged individuals can also be parasitised. 

The wasp not only parasitises individuals, but can also disturb entire aphid colonies.  Colonies may be disturbed by either the female parasitic wasps seeking out hosts or by male parasitic wasps looking for females.  The aphids are alarmed by this and secrete a warning pheromone which warns the whole population.  On reception of this signal, aphids often leave the leaf or fall off it.  Many aphids may die in this way.