There Xylella fastidiosait is a pauca subspecies, it is a gram-negative bacterium well known by those who grow olive trees. This bacterium is responsible for the rapiddrying of the olive tree known as the "complex of rapid drying of the olive tree" (acronym CoDiRO).
The complex of rapid drying of the olive tree is a "new" plant disease, its appearance in Italy dates back to between 2008 and 2010, however, causing more serious damage only recently.
How does it work? By occluding the xylem vessels (the xylem is a kind of circulatory system of the plant) and by preventing vegetation. There xylella fastidiosait is currently widespread in Italy, with a particular focus on Puglia. The neighboring regions would seem unscathed but the proximity to thecrops of infected olive treesthey make fear the worst.
The gram-negative bacterium xylella fastidiosa, in fact, could reach other regions of Italy in different ways, both strictly connected to the olive trade and for activities related to the agricultural world.
In Salento the disease has caused the death of hundreds and hundreds of plants. The strain of the subspecies pauca causes a total and rapid drying of the olive treesespecially those "more adult", such assecular olive trees. While it has been observed that younger plants see less fulminant desiccation.
The Apulian outbreak worsened due to the climatic conditions of the winter of 2013-2014 which saw particularly mild temperatures and more favorable to the spread of vectors of the CoDiRo strain.
Xylella fastidiosa monitoring
The region most at risk of"import"this gram-negative bacterium is Abruzzo. In implementation of Article 4 of Ministerial Decree 12/02/2018, the Abruzzo Region has launched a monitoring and investigation plan to identify which are the "carriers" that could transmit thexylella fastidiosa infection.
Investigations have identified several species ofvector insects, in particular “xilemomize insects” ie insects thatsuck the sapfrom the “xylem” vessels where the bacterium is present.
To be clear: the insect sucks a sick plant and, together with the sap, also "takes" the gram-negative bacterium. The insect itself acts as a "vector" and when it goes to "suck" a healthy plant it will inoculate the bacterium causing the spread of disease. The xylemomic insects that can spread thexylella fastidiosaare several species of the family:
- Aphrophoridae (Philaenus, Neophilaenus, Aphrophora ... species Lepyronica coleoptrata ...)
- Cicadellidae (such as Cicadella viridis species)
The insects of the listed families are all "potential vectors", of these it has been ascertained that the species Philaenus spumarius is the main vector. The Philaenus spumarius species is commonly known asmean spittoon.
Xylella fastidiosa: how to fight
The Phytosanitary Protection Office of the Abruzzo Region in collaboration with olive companies and other trade associations, are hypothesizing different defense methods.
Among the treatments, it was observed that the use of pesticides againstolive flyreduces vector populationsmean spittoonin those olive groves that arise on soil rich in herbaceous vegetation.
Who wondershow to combat xylella fastidiosait should ask itself what are the effective prevention systems. From official investigations, slowing down the spread of its vector would mean confining the area of spread of the disease in the Puglia Region.
For plants already infected there are no alternatives tokilling. Killing is necessary to perpetuate the work of containing the disease.
To date, the "therapy"Saw major containment works to prevent thebacterium xylella fastidiosacan cross over to Puglia. The containment measures have seen the establishment of geographical bands differentiated by intensity of the eradication measures of diseased plants and, as a precaution, of healthy ones that are in a certain proximity to the outbreaks.
Those who hope for a resolutive therapy will have to put all hope away. In March 2017, a study published by the Joint Research Center of the European Commission highlighted that it is no longer possible to eliminate the bacterium from the Salento area.
The gram negative bacterium in question causes severe economic damage to agriculture, not only in the field of olive cultivation. This bacterium is responsible for the olive disease known as “CDO” acronym for olive drying complex. This disease is present in Puglia. The culprit is a subspecies of the bacterium Xylella fastidiosa.
This bacterium is responsible for othersplant diseaseslike the “Pierce's disease” of the vine and the variegated chlorosis of citrus fruits. These diseases have been eradicated after many studies.
In Puglia, there is still no plan to eliminate the subspecies of xylella fastidiosa responsible for the killing of many infected olive trees.