“The scientists isolated the plants from each other above ground, covering them with bags and thereby preventing airborne chemicals (one form of plant communication) from traveling from one plant to the other. Then, the team introduced the aphids. In the plants that were connected by fungi, when a single plant was infected with aphids, the other two plants began to mount their chemical defenses, secreting aphid-repelling substances that also attract the wasps that feed on aphid larvae. The plants that were not connected by mycorrhizae were apparently not warned of the attack on the single plant in their group because they secreted no defensive chemicals.”
