Battling bacterium

A farmer performs grafting on immune wild olive trees in the Salento peninsula, southern Italy. Working in an arid Italian field of crumbly soil, agronomists are battling a rampant bacterium that has already infected millions of olive trees and could threaten the entire Mediterranean basin.

Bacteria Xylella fastidiosa, which has no known cure, has devastated ancient olive trees in Italy’s southern region and beyond, causing 1.2 billion euros ($1.3 billion) of damage to the world's second olive oil exporter after Spain.