The parasitic wasp Aphidius matricariae attacks the green peach aphid, and A. colemani attacks both green peach and melon aphids. These small (less than 1/8 inch) parasitic wasps lay their eggs inside the aphid. The aphids are killed as the developing larvae first feed upon them and then spin their cocoons. The dead aphids turn into tan "mummies". A round exit hole is formed when the parasitic wasp emerges.