Effective biological control for aphids! This tiny parasitic wasp (A. colemani) hones in on its prey by sensing the distress signals of infested plants as well as detecting the aphid’s honeydew secretions. Once there, it injects an egg into the aphid. When the egg hatches, the larvae begin to consume the pest from inside. The resulting wasp then emerges from the rear of the dead aphid to seek out other prey. Surviving aphids react by emitting an “alarm” pheromone which causes the colony to flee, often falling to the ground where they die.

Appropriate for garden and greenhouse use, aphid parasites can be used both as a preventive measure and to combat infestations. Adult wasps live two to three weeks and will lay eggs in as many as 300 aphids over the period of their lives, increasing the numbers of wasps as they do. Proof they’re at work can be found by searching for the brown, mummified shells left of dead aphids.