Plant apocalypse: how new diseases are destroying EU trees and crops

From ancient olive groves to root vegetables, foreign pests introduced via the bloc's open import system are causing damage worth billions - and outbreaks are on the rise

The plants slowly choke to death, wither and dry out. They die en masse, leaves dropping and bark turning grey, creating a sea of monochrome. Since scientists first discovered Xylella fastidiosa in 2013 in Puglia, Italy, it has killed a third of the region's 60 million olive trees - which once produced almost half of Italy's olive oil - many of which were centuries old. Farms stopped producing, olive mills went bankrupt and tourists avoided the area. With no known cure, the bacterium has already caused damage costing about 1bn.

The greatest part of the territory was completely destroyed," says Donato Boscia, a plant virologist and head researcher on Xylella at the Institute for Sustainable Plant Protection in Bari.