Source: Fresh Plaza [summ. Mod.DHA, edited]
The Ministry of Agriculture of Kazakhstan has confiscated 228 tons of seed potatoes from Germany, the Netherlands, and France, as well as 46.4 kg [102.3 lb] of carrot seeds from France contaminated with a dangerous bacterium. The presence of _Candidatus_ Liberibacter solanacearum in potato batches was confirmed by the Almaty Zonal Quarantine Laboratory.
[_Candidatus_ Liberibacter solanacearum (Lso) was found to be associated with zebra chip (ZC) of potato, as well as a yellowing disease of tomato and capsicum in New Zealand. Lso has since also been associated with yellowing diseases of other solanaceous crops and some crops in the family Apiaceae (such as carrots). Main vectors of Lso are the potato psyllid (_Bactericera cockerelli_) in solanaceous host and carrot psyllids (_Trioza apicalis_, _B. trigonica_) in Apiaceae.
The current Lso species is divided into haplotypes: A and B affecting Solanaceae; C, D, and E affecting Apiaceae. Both groups of haplotypes have been reported from North America and New Zealand. Carrot haplotypes have been reported from Europe (ProMED posts 20120713.1199961, 20151009.3702151, 20161130.4666613), northern Africa (ProMED post 20141121.2978030), and the Middle East (ProMED post 20170130.4803773). Potato haplotypes A and B are still considered absent from the European/Mediterranean region. However, haplotype E was also detected in potatoes in Spain [ProMED post 20170802.5222241], representing the 1st report of a haplotype being able to infect both Apiaceae and Solanaceae.
Additional haplotypes, hosts, and vector species are being reported (ProMED post 20190226.6336285) from different regions, further adding to the complexity of the epidemiology and biology of this pathogen. More research is needed on Lso and its haplotypes, its global distribution, and any potential biosecurity implications. Transmission of Lso with or through carrot seeds is still being investigated. Until there is clear confirmation either way, treating seeds as a quarantine risk, as in the case above, is the responsible approach.
Only a few members of _Candidatus_ Liberibacter have been characterised so far, including the pathogens causing citrus greening (see previous ProMED posts in the archives). However, contrary to Lso, greening has a narrow host range limited to citrus crops, due to the host specificity of its psyllid vectors.
http://www.ezilon.com/maps/images/asia/political-map-of-Kazakhstan.gif (with provinces)
Zebra chip of potato:
https://planthealthportal.defra.gov.uk/assets/uploads/Zebra-chip-slices2.jpg (processed and unprocessed infected tubers)
https://gd.eppo.int/media/data/taxon/L/LIBEPS/pics/1024x0/1939.jpg (compared with healthy)
Lso symptoms on tomato:
Information on _Ca._ Liberibacter solanacearum:
https://gd.eppo.int/taxon/LIBEPS (with pictures),
Information on potato zebra chip disease:
Potential Lso transmission via carrot seeds:
Information on Lso psyllid vectors:
_Ca._ L. solanacearum taxonomy:
Taxonomy and information for psyllid vectors (with pictures) via: