With a strong ability to induce often lethal changes in the host plant, Xylella fastidiosa is one of the most dangerous bacteria that attacks economically important crops in many countries. In such a way that, in May 2019, the European Food Safety Authority (EFSA) reinforced the warnings regarding the spread of this disease, which is devastating olive orchards across Europe and for which there is still no cure.

Xylella fastidiosa is especially dangerous because it can stay hidden during different periods. In olive trees, for example, these periods can last a year or more. That is why it is essential to invest in research that allows the control, but also the anticipation, of outbreaks.

In Portugal, the first outbreak of the disease was registered in Vila Nova de Gaia in January 2019, but computer simulations that same year (EFSA data) indicate that the countries most at risk are those in southern Europe.

First detected in Europe in 2013, in a violet outbreak in Apulia, southern Italy, Xylella fastidiosa has since then been reported in France (Corsica and Provence-Alpes-Côte d’Azur), Spain (Balearic Islands, Valencia, Madrid), Central Italy (Tuscany) and Portugal (Porto region).

The bacterium lives in the plant’s xylem tissue and is usually spread by insect vectors that feed on the plant’s xylem. In addition to X. fastidiosa, the most reported subspecies are X. pauca, X. multiplex and X. sandyi.