Xylella: The Plague Killing Puglia’s Ancient Olives
Of all the threats to the olive, this is the one that keeps me up at night. Xylella fastidiosa is a bacterium with no cure, and since 2013 it has been turning the silver groves of southern Italy into grey skeletons.
What it is
Xylella fastidiosa is a bacterial pathogen, spread by sap-sucking insects, that clogs a tree’s water-carrying vessels until it withers and dies. It was confirmed on olive trees in Puglia in October 2013 — the first time it had ever been recorded in the European Union — and by 2015 the infected zone had exploded across the Salento, the deep south of the region.
Why it is a catastrophe
There is no cure. Containment means cutting down infected and surrounding trees — and in Puglia that has meant felling vast numbers of olives, including centuries-old monuments that had survived everything else history threw at them. Over the years that followed, millions of trees were lost, and ancient varieties like the Cellina di Nardò were hit hardest. Replanting now leans on resistant cultivars.
We marvel at thousand-year-old olive trees as if they’re immortal. Xylella is the proof that they aren’t. A landscape that took two millennia to build can be lost in a few years to a pathogen no one saw coming — and a warming, more-connected world makes such plagues more likely, not less. It’s the most sobering story in olives, and it’s still being written.
Background and ongoing monitoring: European Food Safety Authority (EFSA), Xylella fastidiosa.