A ProMED-mail post

<http://www.promedmail.org>

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International Society for Infectious Diseases <http://www.isid.org>

Date: Thu 15 May 2014

Source: FreshPlaza [edited]

<http://www.freshplaza.com/article/120878/Disease-noticed-in-French-carrots>

Over the last 2 winters [2012/13, 2013/14], producers from the 2 main carrot production zones have noticed black marks on the roots towards the end of storage. These symptoms were observed in Aquitaine, Lower Normandy, and Brittany.

These rather dry lesions begin as small browny-black dots along the root. They are no more than 2mm deep. They grow up to 1-2cm in size in an irregular form.

Identification was carried out at INRA [National Agricultural Research Institut] where they found it to be a grey-green fungus which grows very slowly in Petri dishes and resembles _Rhexocercosporidium carotae_.

--

communicated by:

ProMED-mail

<promed@promedmail.org>

[Black spot disease is a serious problem in carrots in northern Europe. It can be caused by several fungi, including _Pseudocercosporidium carotae_ (previously _Rhexocercosporidium carotae_). Leaf spots may occur in the field, but roots usually only become affected after harvest and continue to develop black blotches during time in storage. Cultivars vary in susceptibility, and up to 80 per cent incidence has been reported in some cases. Umbelliferous weeds appear to serve as pathogen reservoirs.

Research is still needed on the epidemiology of _P. carotae_. It is suspected that the fungus can be spread by soil, mechanical means, and possibly with plant material, including seed. Environmental conditions during the cropping season are thought to contribute to disease severity. Until further information on epidemiology becomes available, disease management may include phytosanitation and crop rotation.

It appears from the report above that the diagnosis of the pathogen in France still awaits final confirmation.

Maps

France:

<http://worldatlas.com/webimage/countrys/europe/lgcolor/frcolor.htm>

Regions of France:

<http://www.gite.com/art/france-map/map-of-france-regions.jpg>

Pictures

Black spot disease on carrot roots:

<http://www.lr.no/media/ring/1043/gulrotsvartflekk%20t%20korr%20foto%20Mariann%20Wikstr%C3%B8m.jpg>

Links

Information on _P. carotae_ black spot:

<http://www.gartneriraadgivningen.dk/NR/rdonlyres/1E808518-8AD6-4911-B693-18090C732BB1/0/MariannochSaraDanmark2012.pdf>

and

<http://link.springer.com/article/10.1007%2Fs10658-006-9098-0/fulltext.html>

Carrot black spot disease:

<http://orgprints.org/7314/1/Black_spot_diseases_in_carrot.pdf>

_P. carotae_ taxonomy and synonyms:

<http://www.indexfungorum.org/names/NamesRecord.asp?RecordID=104667>

and

<http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=104667>.

- Mod.DHA

A HealthMap/ProMED-mail map can be accessed at:

<http://healthmap.org/promed/p/100>.]

Website: http://www.isid.org

Published: May 22, 2014