On 31 October 2016, ANSES received a formal request from the Directorate General for Food (DGAL) to undertake the following expert appraisal: a pest risk analysis for huanglongbing disease in the European Union.

BACKGROUND AND PURPOSE OF THE REQUEST

Huanglongbing (HLB, or citrus greening or yellow dragon disease) is currently one of the greatest threats to the health of citrus crops. Therefore, the introduction and spread of the various species of Candidatus Liberibacter spp. (CL) – three of which (Candidatus Liberibacter africanus,  americanus and asiaticus) are the causal agents of this disease – are prohibited by plant health regulations in the European Union (Annex I, Part A, Section 1 of Directive 2000/29/EC, June 2014  version).
This disease affects a large part of South-east Asia as well as America and Africa. It is absent from Europe. As for the overseas territories of France, it has been found in the West Indies  and on Reunion Island.

In the summer of 2015, the disease was suspected in a citrus orchard in the Algarve region of Portugal. Nonetheless, following additional tests for the detection of this bacterium, combined with an intensive monitoring and sampling programme, the region was declared free of ‘Candidatus Liberibacter asiaticus’ by Portugal's national plant protection organisation (NPPO) (EPPO, Rsf-1602).
Furthermore, in the same year, the disease was first reported in North Africa, specifically in Egypt, a country that exports citrus fruit to Europe (Tolba and Soliman, 2015).

Purpose of the request

In order to protect citrus-producing European Mediterranean countries from possible economic impacts arising from these bacteria, a risk assessment was requested for the entire European Union, with the aim of preventing both the introduction of this pest into Europe and its spread if introduction should occur, since one of its vectors, Trioza erytreae, is present in Portugal and Spain.
ANSES was thus asked to undertake a pest risk analysis (PRA) for Candidatus Liberibacter spp. for the entire European Union.