ROME (Reuters) - European countries can be forced to cull olive trees to stop the spread of a deadly bacterium, the European Union ruled on Thursday, sparking concern in a grove-dotted region of Italy.

The EU court rejected an appeal from an Italian tribunal over a European Commission order to destroy all olive trees potentially infected with the Xylella fastidiosa pathogen, called "olive tree leprosy".

The controversial cull order came into force last year in the Puglia region in Italy's "heel", but the regional Italian court suspended it and questioned the Commission directive.

In response, the Luxembourg-based EU court said in a written ruling that removing both infected plants and apparently healthy ones nearby was necessary to stop the spread of the bacteria, which is carried by flying bugs.

Puglia governor Michele Emiliano said he wanted to meet European authorities to discuss compensation for farmers affected by the "drastic measures that risk unimaginable consequences for our countryside and our economy".

In a statement, Emiliano added that he wanted "a plan to safeguard our irreplaceable woodland assets, starting from our centuries-old olive trees".

When Xylella fastidiosa, which dries out the plants' leaves, was diagnosed in Puglia in 2013, it was the first time it had been found in Europe. It later spread further north and blighted the harvest in Italy.

The EU court said it had not conclusively proved a causal link between the bacteria and the rapid drying out seen in some Italian olive trees, but said there was a "strong correlation" which justified the cull.

Matteo Salvini, leader of the eurosceptic Northern League party, hit out at the ruling, comparing the European Union to the Soviet Union. "Will the next order be to pull out all the grapevines in Chianti or the Veneto?" he asked.

Last year, a Puglia prosecutor sequestered 2,000 olive trees that had been destined for the chop and placed 10 people under investigation over their handling of the outbreak. The probe is still underway.

(Reporting by Vincenzo Damiani in Bari and Isla Binnie in Rome; Editing by Catherine Evans)