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Published Date: 2018-01-05 04:00:53
Subject: PRO/PL> Liberibacter solanacearum, parsley - Australia: 1st rep (NS)
Archive Number: 20180105.5538875
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases

Date: August 2017
Source: Nursery & Garden Industry Australia (NGIA) [edited]

_Candidatus_ Liberibacter solanacearum has been detected in New South Wales in the Italian Giant variety of imported parsley seed. In most cases, the bacterium does not damage parsley plants but has the potential to cause serious damage to some other Apiaceae crops which include carrot, celery, chervil, fennel, and parsnip.

This is the 1st time this bacterium has been detected in Australia. Whilst [it] is spread by psyllids, these particular psyllids are not present in Australia.

The seeds originated in France but were imported through a supplier in Italy. The NSW Department of Primary Industries is tracing the affected seeds [to] determine the extent of their distribution. These seeds were imported prior to emergency measures introduced in April 2017.

communicated by:
IBIS (International Biosecurity Intelligence System)

[Only a few members of _Candidatus_ Liberibacter have been characterised so far, including the pathogens causing citrus greening (see previous ProMED-mail posts in the archives) which is limited to these crops due to the host specificity of the psyllid vectors.

_Ca._ 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. Main vectors of Lso are the potato psyllid (_Bactericera cockerelli_) in solanaceous host and carrot psyllids (_Trioza apicalis_, _Bactericera trigonica_) in Apiaceae. These vectors have a much wider host range than the greening vectors and additional vector species are also being identified, further extending potential host range and economic impact of Lso.

The 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 the Americas and New Zealand. Carrot haplotypes have been reported from Europe (ProMED-mail posts 20120713.119996120151009.3702151,20161130.4666613), northern Africa (ProMED-mail post 20141121.2978030) and the Middle East (ProMED-mail post 20170130.4803773). However, haplotype E was recently also detected in potatoes in Spain [ProMED-mail post 20170802.5222241], representing the 1st report of a haplotype being able to infect both Apiaceae and Solanaceae. This suggests that a lot more research is needed on epidemiology, biology and distribution of Lso worldwide.

Lso haplotypes D and E were shown to be present in different cultivars of commercial parsley seed from different sources in the UK (see link below). Thus, Lso infection in commercial parsley appears to be widespread but largely asymptomatic. Furthermore, Lso vector psyllids feed on this crop. This makes parsley a likely reservoir host for Lso and thus an international quarantine risk.

(This report was received by ProMED-mail with delay, but it is of ongoing significance.)

Australia (with states):

Lso affected carrot: and (compared with healthy)
Lso symptoms on tomato: and
Zebra chip of potato:,, and (processed infected tuber, compared with healthy)
Lso, microscopy:
Lso photo gallery:
Carrot psyllid:

Additional news story:
NGIA biosecurity alert:
Information on _Ca._ Liberibacter solanacearum:,,, and via
Lso haplotypes: and
Lso on parsley seed:
Information on Lso psyllid vectors:,,, and
Information on potato zebra chip disease: and
_Ca._ L. solanacearum taxonomy:
Genus _Ca._ Liberibacter taxonomy and species list:
Information and resources for psyllids: - Mod.DHA]

See Also

Liberibacter, carrot - Greece: 1st rep (TC) 20171112.5435078
Liberibacter solanacearum, potato - Spain: (CB) 20170802.5222241
Liberibacter, carrot - Israel: 1st rep 20170130.4803773
Liberibacter, carrot - Sweden: (HA) 20161130.4666613
Liberibacter, carrot - Germany: 1st rep (NI) 20151009.3702151
Liberibacter, solanaceous crops - Norfolk Island: 1st rep. 20150417.3303297
Liberibacter, carrot - Africa: 1st rep, Morocco 20141121.2978030
Liberibacter, vegetable crops - multicountry 20120713.1199961
and older items in the archives

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