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

With the bacteria spreading beyond predictability, an evolving patchwork of strategies aim to identify and contain outbreaks.

Infected olive tree (bacterium Xylella fastidiosa), Salento, Italy
Jun. 17, 2020
By Paolo DeAndreis
Infected olive tree (bacterium Xylella fastidiosa), Salento, Italy

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

We need to change the approach and inten­sify both pre­ven­tion and inter­ven­tion activ­i­ties.- Coldiretti, Italian Farmers’ Association

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.

See Also:Xylella Fastidiosa

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.”


Olives trees in Salento infected with Xylella

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 7th 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.”


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