Xylella fastidiosa: the parasitic bacterium of the olive tree

The recent history of agriculture is full of catastrophes due to the onset or development of new pathogens or parasites: these events can be limited to certain continents, as has happened to the potato plant in Europe, the coffee plantations in South East Asia, to the pear and citrus fruit-trees in America, or can be extended globally (as in the case of the vine).

The vine cultivation was, until the middle of the nineteenth century, devoid of any real plant or animal pests capable of destroying plantations; but with the exchange of new study material, new pathogens were introduced: these progressed slowly but inexorably from the second half of the 18th century and risked extinguishing the species, due to the fact that the Vitis Vinifera had no real defence against them.

For the olive trees, the new threat is the Xylella fastidiosa, a bacteria that invades woody tissues and causes decay and desiccation of the plant. Since no means of killing the pathogen has been found, attempts have been made to limit its diffusion.

Having been introduced a few years ago in the Leccese province, it has found a variety extremely susceptible to its attack, the cultivar Cellina di Nardò, which is present on the territory with millions of secular plants: in many cases these plants have not been cured and the bacterium has spread rapidly, among the uncertainties of the technicians and of the public opinion, torn between safeguarding the heritage of centuries-old plants from explantation, or safeguarding the entire traditional olive tree growing from contamination.

How to treat Xylella fastidiosa

Currently, an attempt is being made to hinder its spread by creating a phytosanitary barrier capable of containing the infestation with certain areas and prohibiting the diffusion of plant material outside the affected areas; the international community looks with extreme attention and concern to the attempts to combat it, since the Xylella not only threatens the olive tree, but other components of the Mediterranean, and, having found no resistent varieties, it could become a threat to the ecosystem and its landscape.