Candidatus Liberibacter solanacearum

(Zebra chip disease)

•  Causal agent and transmission

Candidatus Liberibacter solanacearum is not cultivable bacteria (obligatory plant parasite) which is limited to the plants phloem.

Polymorphism on the genome of the bacterium resulted in the description of five haplotypes (or types of strains). Haplotypes A and B are related to Solanaceae and are transmitted by psylla Bactericera cockerelli whereas the haplotypes C, D and E are described on Apiaceae and are transmitted by the psylla Bactericera trigonica and Trioza apicalis.

• Significance and regulation

Zebra Chip disease has been described for the first time in Mexico in 1994. Since then, it has spread to several countries in Central America and in North America (it is reported in 15 States in the United States) as well as in New Zealand and Norfolk Island.

This disease has never been reported in Europe in crops of potato or other solanaceous plants; haplotypes A and B of Ca. L. solanacearum and their vector Bactericera cockerelli have never been described in Europe. The strains which have been described on Solanaceae (A and B) as well as their vector psylla, Bactericera cockerelli, are on the A1 list of EPPO (absent quarantine organisms of the EPPO region). They are also listed in France as a category I pest by Ministerial Decree of December 15, 2014.

The haplotypes C, D and E have been described on Apiaceae in several European countries on carrot and celery and their (psylla) vectors are not regulated in Europe.

More informations on the website of the CaLiso project