[1] It is native to the northeastern United States but has been introduced to other parts of the world as a biological pest control agent.

The adult A. mali is a tiny black wasp slightly smaller than its woolly aphid host.

When ready to emerge, the adult chews its way out through the upper surface of the aphid, leaving a neat round hole.

[2] Introduced from its native region to other apple growing areas, A. mali was one of the earliest examples of controlling pests biologically.

It works best in conjunction with other generalist predators such as lady beetles, lacewings, the larvae of hoverflies and the plant bug Deraeocoris brevis, and is negatively impacted by the use of chemical pesticides.