PRO/PL> Wart disease, potato

Published Date: 2012-08-20 10:30:51
Subject: PRO/PL Wart disease, potato – UK: (N Ireland) eradication
Archive Number: 20120820.1252253

WART DISEASE, POTATO – UK: (NORTHERN IRELAND) ERADICATION
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A ProMED-mail post
http://www.promedmail.org
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International Society for Infectious Diseases
http://www.isid.org

Date: Fri 17 Aug 2012

Source: FreshPlaza [edited]

http://www.freshplaza.com/news_detail.asp?id=99728

Northern Ireland free of potato wart disease after 50 years

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750 fields in Northern Ireland have faced potato growing restrictions for the past 50 years, but this is now at an end.

The fields were once contaminated by potato wart disease, which affected Ireland in the early 20th century. Northern Ireland has not had a case since 1959, but the disease is virulent and can remain in the soil for over 30 years. As a result the fields had to be kept clear of seed potatoes until now, when the restrictions have been lifted.

This restrictions applied to some 70 000 acres [about 173 000 acres] of cultivation overall. The move to remove the restrictions comes after 10 years of sampling and testing of affected land, between 2001 and 2011.

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Communicated by:

ProMED-mail

promed@promedmail.org

[Potato wart disease is caused by the fungus _Synchytrium endobioticum_, which is considered one of the most important pathogens of the crop. It is endemic in Europe and also reported from a number of locations in the Americas, Australasia, and Africa. The pathogen can also affect tomato and some solanaceous weeds and has been included in the quarantine lists of the European Plant Protection Organisation (EPPO).

On infected tubers, 'eyes' develop into characteristic warty, cauliflower-like swellings. If infected early, the whole tuber can be replaced by a warty proliferation. Warts darken with age and eventually rot and disintegrate. Diagnosis requires laboratory confirmation as similar symptoms can be caused by other pathogens. The fungus goes through cycles of proliferation and reinfection as long as cool, wet conditions prevail and is therefore less damaging in warm, light, well drained soils.

The disease is spread with soil (for example on farm tools), by infected seed tubers, and also in manure from animals fed on infected potatoes. The fungus can survive in soil for up to 40 years in the absence of a host. Disease management is based on the control of pathogen spread since fungicides are ineffective. There are several pathotypes defined by their virulence on different host cultivars. Potato varieties resistant to a number of them have been developed but new pathogen strains are emerging compromising the efficacy of host plant resistance.

A potato wart free status of Northern Ireland will result in economic and trade advantages for regional potato growers. Furthermore, this represents an important achievement since eradication of plant pathogens is extremely difficult and rarely successful.

Maps

UK:

http://www.lib.utexas.edu/maps/europe/united_kingdom.gif and

http://healthmap.org/r/1KlI

Pictures

Potato wart symptoms:

http://www.agf.gov.bc.ca/cropprot/images/wart.jpg,

http://www.apsnet.org/publications/apsnetfeatures/Article%20Images/Potato_Fig01.jpg,

http://www.forestryimages.org/images/768x512/0454023.jpg,

http://agri.nv.gov/images/potato%20wart.jpg, and

http://plant-disease.ippc.orst.edu/plant_images/PotatoWartSingleTuber2.jpg

Photo gallery of tuber symptoms and fungal structures: