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.
