Xylella Update: Spread Continues in Southern Italy Amid Calls for Swift Action

The lat­est Xylella fas­tidiosa out­break in Puglia showed how eas­ily the bac­te­ria spreads beyond the already iden­ti­fied areas of con­tain­ment and obser­va­tion.

With eigh­teen new infected olive trees in the area of Locorotondo, not far from Bari, in Puglia, and five more in the last two weeks, the pres­ence of Xylella was con­firmed as wide­spread in more Apulian ter­ri­to­ries.

“The new infec­tions show that the dis­ease con­tin­ues to migrate,” said Savino Muraglia, pres­i­dent of the Apulian branch of the Coldiretti farm­ers asso­ci­a­tion.

“This draws a dark sce­nario caused by delays in the removal of the infected olive trees, as it hap­pened in April 2015, when it was decided not to remove 47 trees in an out­break that then car­ried on to infect 3,100 other trees, includ­ing mon­u­men­tal olive trees, and hit both the olive and land­scape her­itage of the Brindisi and Taranto province,” Muraglia said.

That sce­nario is why the local Authority on Forestry, ARIF, is push­ing for a quicker response to the new infec­tions. The insti­tu­tion con­firmed that all of the newly-found infected trees will be removed in the next few days.

“That swift response to the spread­ing of the infec­tion is an excel­lent result,” said the ARIF Extraordinary Commissioner Gennaro Ranieri, ​“due not only to the insti­tu­tional col­lab­o­ra­tion but above all to the sen­si­tiv­ity of the landown­ers.”

“Despite the suf­fer­ing caused by the felling of olive trees that rep­re­sent not only an eco­nomic resource but also a piece of fam­ily his­tory, have allowed oper­a­tions to take place imme­di­ately,” Ranieri explained.

While there have been many calls for more timely responses to new infec­tions, not all agree on the scope and means of such actions in already infected areas, also known as red zones.

In a joint state­ment, WWF Italy, the Torre Guaceto Natural Reserve Consortium and Slow Food Puglia asked the Puglia Region author­i­ties to avoid any fur­ther removal of the infected trees because ​“the only use­ful action against the fur­ther dis­sem­i­na­tion of the bac­te­ria within the red zones is to com­bat the insect car­rier.”

The three asso­ci­a­tions asked the author­i­ties to save the mon­u­men­tal olive trees and respect the deci­sion of the TAR (Regional Administrative Tribunal) that sus­pended the removal of trees in the red zones because in those areas the infec­tion is con­sid­ered endemic.

In those areas, say the asso­ci­a­tions, some farm­ers have been able to suc­cess­fully take care of their trees and even bring them back to olive oil pro­duc­tion. The idea is that farm­ers and grow­ers have the right to do what­ever they can to save their trees.

“We are try­ing to give a hand to farm­ers in those areas as we always did,” Marcello Longo, Slow Food Puglia pres­i­dent, told Olive Oil Times. ​“We set up a Slow Food pre­sid­ium for those who pro­duce olive oil in the hit areas and will be on their side at this moment, as we did before and even more dur­ing the worst times of the Covid-19 epi­demic.”

To help the farm­ers hit by Xylella in the red zones and pro­vide bet­ter resilience against infec­tions, Coldiretti asked for a spe­cial autho­riza­tion that should be given to grow­ers who would want to replace the removed olive trees with cherry and almond — trees that are much less likely to be infected by Xylella than the olives.

The asso­ci­a­tion noted that the area is well suited for trees that could bring new sources of income to farm­ers.

“The diver­si­fi­ca­tion of our crops is essen­tial to restore the area,” said Gianni Cantele, pres­i­dent of the Lecce branch of Coldiretti. Farmers, said Cantele, should be able to pro­ceed with ​“replant­ing, graft­ing, and exper­i­men­ta­tion, giv­ing pri­or­ity to all host plants belong­ing to vari­eties for which there is sci­en­tific evi­dence, although not defin­i­tive, on tol­er­ance and resis­tance to the bac­terium.”

The Italian gov­ern­ment has announced another €190 mil­lion ($214 mil­lion) against Xylella on top of the €35 mil­lion ($39 mil­lion) recently deployed. The Ministry of Agriculture allo­cated €40 mil­lion ($45 mil­lion) for the replace­ment of removed olive trees, while €25 mil­lion ($28 mil­lion) will go to the plant­ing of other kinds of trees. The remain­ing funds will be allo­cated as sol­i­dar­ity fis­cal funds for the local farm­ing com­pa­nies, with ben­e­fits extend­ing for a max­i­mum of three years.

A push towards a more mod­u­lar approach to the Xylella out­break, based on areas with dif­fer­ent lev­els of infec­tion, came in the last few days from the European Union Food Safety Authority (EFSA).

In its new guide­lines for EU mem­ber states deal­ing with the many chal­lenges posed by the mon­i­tor­ing of the dis­ease, EFSA pro­vides meth­ods to dif­fer­en­ti­ate the sur­veyed areas.

“Based on exam­ples,” said EFSA in a note, ​“three dif­fer­ent sur­vey designs are sim­u­lated: detec­tion sur­veys to sub­stan­ti­ate pest free­dom, delim­it­ing sur­veys to deter­mine the bound­aries of an infected zone, and buffer zone sur­veys to mon­i­tor a zone ensur­ing pest detec­tion at a low level of preva­lence.”

For EFSA that ​“extremely flex­i­ble approaches allow sur­veys to be tai­lored to each spe­cific sit­u­a­tion in the mem­ber states, tak­ing into account the host plants, vec­tors, cli­mate suit­abil­ity and resources avail­able.”

The European Commission will con­clude a pub­lic con­sul­ta­tion on July 7^th to define a new approach to the Xylella con­tain­ment. While the EU pro­posal reit­er­ates the need for the removal of the infected trees, it also eases some pre­vi­ous mea­sures.

It pro­vided for the halv­ing, from 100 to 50 meters, of the radius within which the plants not infected by Xylella should be cut, the reduc­tion of the buffer areas and removal of the vine from the list of plants that are sus­cep­ti­ble to infec­tion. In the newly defined areas, mon­u­men­tal trees and other plants con­sid­ered of cul­tural and social rel­e­vance will be spared from erad­i­ca­tion.

In a note, Coldiretti stressed the urgency of strong European coor­di­na­tion to com­bat Xylella. ​“The dis­ease has been detected in France, Spain, Germany and Portugal, with the bac­te­ria spread­ing north,” the Italian farm­ers asso­ci­a­tion noted. ​“We need to change the approach and inten­sify both pre­ven­tion and inter­ven­tion activ­i­ties.”

Until now, sev­eral coun­tries chose to pro­ceed with national poli­cies on the mat­ter, like the U.K., where the gov­ern­ment and the European Union are cur­rently debat­ing the ban intro­duced by London to halt the import of any plant, like olive, laven­der or rose­mary, that the British Government believes could be Xylella car­ri­ers.

EFSA has stressed that the most chal­leng­ing task of all remains the detec­tion of the infec­tion, which has shown to be able to spread well beyond pre­dictabil­ity.

The mon­i­tor­ing cam­paigns are mostly focused on trees that show symp­toms of the bac­te­ria even if trees with no symp­toms at all can prop­a­gate the infec­tion. With the goal of early detec­tion, tech­nol­ogy can play a key role. Just a few days ago, the Apulian aero­space tech­nol­ogy com­pany DTA pre­sented its ​“Redox” project, a sys­tem for the aer­ial mon­i­tor­ing of the Xylella-infected areas.

With its insti­tu­tional part­ners, like the National Research Council (CNR) and the Aviation Authority (ENAV), DTA is devel­op­ing an inte­grated tech­nol­ogy for the mon­i­tor­ing in vast areas, using drones and ther­mal sen­sors.

The goal is to deploy tech­nolo­gies and pro­ce­dures for the acqui­si­tion, trans­mis­sion, stor­age, pro­cess­ing and shar­ing of remote sens­ing data acquired with dig­i­tal sen­sors mounted on satel­lites, air­planes, drones and ter­res­trial plat­forms that iden­tify olive trees infected with Xylella fas­tidiosa even before the onset of symp­toms vis­i­ble to the naked eye.

“The use of hyper­spec­tral sen­sors and ther­mal cham­bers made avail­able by CNR,” said the com­pany in a note, ​“will guar­an­tee con­tin­u­ous mon­i­tor­ing of large areas, even tens of thou­sands of square kilo­me­ters, like an entire region.”

• Ministry of Agriculture funds against Xylella


• EU pro­posal on Xylella con­tain­ment