Paco, a very good boy, gets a pat on the head amidst his efforts to detect Xylella (Credit: Agostino Petroni) Xylella fastiodiosa is a bacterium that clogs the xylem (the vessels that carry water from the roots to the leaves) of trees and other woody plants and slowly chokes them to death.You might also like: - Italy's plan to save Venice from sinking - The lost generation of ancient trees - The vegan leather made from flowers With its 60 million olive trees, Puglia used to produce up to 50% of Italy's olive oil, but in just a few years, Xylella infected and killed 21 million trees, many of which were several centuries old.However, the regional governor President Michele Emiliano was initially sceptical about a link between Xylella and the rapid desiccation of olive trees."The President has launched an important action of listening to everyone, organising public assemblies, personally participating in all the events to which he was invited, to bring an issue as complex, dramatic and divisive as Xylella into the context of a civil dialogue," the spokesperson said.The Labrador is not the only breed to make an excellent super-sniffer, as Ellis the seven-year-old springer spaniel can attest (Credit: Agostino Petroni) As the bacteria keeps spreading northward at a rate of about 20km (12 miles) per year, popping up in other regions of Italy and Europe too, governments are concerned, while scientists and plant inspectors are racing to contain the disease and prevent it from spreading further."