Xylella Outbreak in Apulian Buffer Zone Puts Millenary Trees at Risk

One of the most rel­e­vant olive oil pro­duc­ing areas in the south­ern Italian region of Puglia is once again under the attack from Xylella fas­tidiosa.

A new out­break of the deadly plant pathogen has been dis­cov­ered by the Italian author­i­ties in sev­eral olive trees close to Monopoli, in what is con­sid­ered the epi­demic buffer zone, a crit­i­cal mon­i­tor­ing area located between the infected and the safe zones.

“We found the infec­tion spread to 50 olive trees in the Monopoli sur­round­ings,” the Xylella experts from the Regional Agency of Water and Forestry (Arif) wrote.

“The olive trees are part of the buffer zone that lies along Road 16,” the agen­cy’s sci­en­tists added. ​“They are part of the mon­u­men­tal olive tree val­ley, which is the coastal Adriatic strip (of trees) that passes from north to south through the safe zone, the buffer zone, the con­tain­ment and the infected areas.”

The pres­ence of the bac­te­ria in that loca­tion is unprece­dented. Apulian gov­er­nor Michele Emiliano said that the new infec­tions are ​“another con­fir­ma­tion that this dis­ease spreads in an unpre­dictable way, with out­breaks pop­ping up in the mid­dle of areas where the infec­tion level until that moment is con­sid­ered very low or non-exis­tent.”

“It is the first time that we find infected trees in the buffer zone, in its north­ern bor­der, just by the safe zone,” the sci­en­tists from Arif added. ​“One of those trees is actu­ally part of what we con­sid­ered the safe zone.”

The sci­en­tists empha­sized how the prox­im­ity of the infected area to Road 16 sug­gests that the road may have played a role in the out­break of the Xylella in this new area.

The spit­tle­bug, one of the main vec­tors of the dis­ease, is noto­ri­ously attracted to cars and is often moved around the region by means of human trans­porta­tion.

Researchers are now at work to mea­sure the scope of the out­break and estab­lish a new buffer zone around the infected trees. Examinations of sam­ples has already begun.

As pre­scribed by the European Union’s Xylella con­tain­ment mea­sures, those analy­ses will iden­tify which trees and other plants have to be removed in the area and lead to the estab­lish­ment of a rede­fined buffer zone.

The local author­i­ties stressed that the mon­i­tor­ing oper­a­tions in the sur­round­ings are now being extended beyond the pre­scribed 100-meter (330-foot) radius around the infected plants.

“The out­break has been dis­cov­ered thanks to the annual mon­i­tor­ing oper­a­tions that already led to the exam­i­na­tion of more than 100,000 sam­ples, of which only 149 have been found to be infected,” the Arif sci­en­tists said.

The lat­est out­break comes as the tree removal oper­a­tions are under­way in the nearby areas of Ostuni, Fasano and Cisternino, where almost 80 infected trees were iden­ti­fied in the past few weeks.

The local branch of the farm­ers asso­ci­a­tion, Coldiretti, asked that the new out­break, which is directly men­ac­ing the region’s famed mil­lenary olive trees, push all inter­ested par­ties toward a new approach.

“In Fasano, Ostuni, Carovigno and Monopoli, there are more than 250,000 olive trees, of extra­or­di­nary value, con­sid­ered by UNESCO for its world her­itage list,” the Coldiretti Puglia pres­i­dent, Savino Muraglia, said. ​“We can­not allow this immense her­itage to be lost.”

Coldiretti has already been crit­i­cal of the author­i­ties’ efforts to stem the spread of the dis­ease and said ​“there is still no shared strat­egy among regional, national and European author­i­ties to stop the dis­ease.”

In the last six years, Xylella fas­tidiosa has impacted olive orchards across the region, caus­ing €1.6 bil­lion (almost $1.9 bil­lion) worth of dam­age.

According to Coldiretti, the dis­ease con­tin­ues to spread north­ward in Italy and the European Food Safety Authority has also warned of new out­breaks that are tak­ing place in other mem­ber states, includ­ing France, Spain, Portugal and Germany.

• Puglian regional gov­ern­ment
• Arif Puglia
• Coldiretti