Also known as the African citrus psyllid, Trioza erytreae is a biting-sucking insect that causes considerable direct damage to citrus fruits and other ornamental hosts, and is the vector of citrus greening disease. Also know as Huanglongbing disease, it is considered the most serious illness worldwide for these plant species. The disease is caused by the bacterium Candidatus liberibacter africanus.

In Africa and the Middle East, T. erytreae transmits this pathogen directly and under natural conditions; however, it has already been demonstrated in the laboratory that it also has the capacity to transmit its Asian form (Candidatus liberibacter asiaticum).

With an established presence in Africa and in some regions of the Middle East, this insect listed as a quarantine pest can also settle and spread in Mediterranean countries and has already been detected in Portugal.

Although the bacterium causing citrus greening has not been identified in Europe, the insect is present in Galicia, on the north and central coast of Portugal, in the Canary Islands and Madeira. With the vector in Portugal, the likelihood of citrus greening introduction and dispersal is high.

The presence of a quarantine pest, officially confirmed, in a part of the territory in which it was previously absent, requires the establishment of demarcated areas. The updated list of civil parishes that make up the demarcated zone (infested areas) and the buffer zone (totally or partially comprised parishes, in a surrounding area within a radius of three kilometers with no signs of the presence of T. eritreae) can be accessed through DGAV’s website.

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.