A roadside stop reveals why every young River Red Gum was dying

Roadside investigations of psyllids, ants and eucs

Driving a country highway, a field biologist notices that every young River Red Gum recruit looks dead or dying, and only that species. Stopping to look closer, he finds leaves riddled with holes and meat ants crawling through the canopy — the signature of a psyllid outbreak. He traces the likely cause to plant chemistry rather than drought, and finds a 1994 study that overturns his water-stress theory.