A
ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>
Date: June 4, 2008
Source:
NZ Ministry of Agriculture and Forestry (MAF) media centre
[edited] <http://www.maf.govt.nz/mafnet/press/2008/080604tomatoes.htm>
New bacterium affects fresh
tomatoes and capsicums
MAF Biosecurity New Zealand (MAFBNZ) has today [4 Jun 2008]
withdrawn phytosanitary certification for New Zealand fresh
tomato and capsicum export produce until further notice,
following the confirmation of a new disease-causing bacterium in
3 commercial hothouse operations in the North Island.
MAFBNZ Director of Border Standards, Tim Knox, says the
withdrawal of phytosanitary certification is a precautionary
measure until more information about the bacterium is available.
Mr Knox says little is known about if or how the bacterium may
have entered New Zealand, or its transmission, effect, and
distribution -- "we have initiated a programme of research to
answer these questions. The results of this research will help
determine the feasibility of options for managing the disease.
Initial findings suggest that the bacterium may be transmitted
by a small insect called the tomato/potato psyllid -- there are
no considered human health issues associated with the bacterium
or with eating [affected] tomatoes or capsicum."
Mr Knox says MAFBNZ is working closely with Horticulture New
Zealand and sector representatives from the fresh tomato and
capsicum industry to discuss the situation and consider possible
response options.
Communicated by:
ProMED-mail
<promed@promedmail.org>
[The bacterium has been identified as a previously undescribed
species belonging to the genus _Candidatus_ Liberibacter (E.
Yamoah, MAF Biosecurity, personal communication). It affects
both the growth and quality of plants and reduces yield.
Symptoms have been detected in both leaves and fruit of tomato
and capsicum and may vary across varieties and growing
conditions in glasshouse or field crops.
Symptoms in tomatoes include leaf curling and yellowing,
stunting of the plant, and leaf stalks may become very
elongated. Fruit may be distorted with a strawberry-like
appearance and fruit development may be uneven. However,
infected fruits may also be asymptomatic and therefore pose a
risk for biosecurity. Symptoms in capsicums include pale green
or yellow leaves with spiky tips, leaf distortion, shortening of
leaf stalks, flower drop, and dieback of plant tops.
The discovery of this new pathogen is very significant since
only a few members of _Ca._ Liberibacter (a genus of fastidious
phloem-inhabiting bacteria) have been characterised so far. The
genus includes the pathogens causing citrus greening
(huanglongbing, HLB) in different parts of the world (_Ca._ L.
asiaticus, africanus, and americanus). HLB is one of the most
damaging diseases of citrus crops affecting leaves and fruits.
For more information on HLB see links and previous ProMED-mail
posts in the archives below.
HLB is transmitted by citrus psyllid vectors and is restricted
to _Citrus_ and close relatives because of the narrow host range
of its specific vectors. The tomato (or potato) psyllid
_Paratrioza
(Bactericera) cockerelli_ suspected to be a vector of the new
Liberibacter species has a rather wide host range including
species in 20 plant families (with strong preference for
solanaceous species), and this can be expected to impact on the
epidemiology of this new disease.
Maps of New Zealand
<http://www.backpack-newzealand.com/images/new-zealand-map.gif>
and <http://healthmap.org/promed?v=-42.4,172.7,5>
Pictures
Tomato/potato psyllids:
<http://insects.tamu.edu/images/insects/common/images/a-txt/aimg91.html>
(adults)
<http://www.insectimages.org/browse/detail.cfm?imgnum=1327131>
(immatures) Citrus greening symptoms and vectors, photo gallery:
<http://www.aphis.usda.gov/plant_health/plant_pest_info/citrus_greening/gallery.shtml>
Links
Additional news story, including symptom description:
<http://www.scoop.co.nz/stories/SC0806/S00004.htm>
Information on tomato/potato psyllid:
<http://insects.tamu.edu/fieldguide/aimg91.html>
and
<http://www.academicjournals.org/AJAR/PDF/pdf%202008/Jan/Abdullah.pdf>
_P. cockerelli_ taxonomy:
<http://zipcodezoo.com/Animals/P/Paratrioza_cockerelli.asp>
Genus _Ca._ Liberibacter taxonomy and species list:
<http://beta.uniprot.org/taxonomy/34019>
Citrus greening data sheet:
<http://spdn.ifas.ufl.edu/EPPO_data_sheet.pdf>.
- Mod.DHA]
[see also in
the
archive:
Huanglongbing, citrus - Bhutan: (Chukha) 20080520.1676
2008
----
Huanglongbing, citrus - USA: (TX), vector quarantine
20071212.4000 Huanglongbing, citrus - Viet Nam, USA: new
biocontrol 20070912.3018 Huanglongbing & citrus tristeza virus,
citrus - Philippines (NV) 20070709.2175 Huanglongbing, citrus -
Pakistan, US (FL) 20070616.1961] |
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