ProMED
http://www.promedmail.org

Source: North American Plant Protection Organization (NAPPO) [edited]
https://www.pestalerts.org/official-pest-report/new-report-potato-wart-synchytrium-endobioticum-prince-edward-island-canada-0

The Canadian Food Inspection Agency (CFIA) has recently confirmed the presence of potato wart (_Synchytrium endobioticum_) in 2 fields on a farm in Prince Edward Island (PEI). Potato wart is a regulated quarantine pest in Canada. [It] reduces yield and can make potatoes unmarketable.

The CFIA has placed the fields under quarantine and is carrying out official control measures under the authority of the federal Plant Protection Act and Plant Protection Regulations, and as part of Canada's Potato Wart Domestic Long-Term Management Plan. Measures include surveillance; controlling the movement of equipment, tubers, plant material and soil; cleaning and disinfecting machinery to prevent spread of the pest.

The CFIA, the PEI government and PEI industry associations are working together collaboratively to control this pest. The Potato Wart Domestic Long-Term Management Plan was established after an initial finding of potato wart in PEI in 2000 [ProMED-mail post 20001028.1877] in order to respond to detections of the pest and to prevent trade disruptions.
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[Potato wart disease (PW) 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 has also been reported from a number of locations in the Americas, Australasia, and Africa. The pathogen can also affect tomato and some solanaceous weeds.

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. Plant vigour is reduced, both quantity and quality of harvested tubers are severely affected. Diagnosis requires laboratory confirmation, as similar symptoms can be caused by other pathogens. The fungus goes through cycles of proliferation and re-infection 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 pathogen exclusion by quarantine regulations and the control of local pathogen spread. Use of certified clean seed tubers is crucial, contaminated seed lines pose major risks of losses both in yield and international trade. Fungicides are ineffective, but some experimental fumigation treatments have been shown to kill resting sporangia (see link below).

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.

After its first detection on PEI in 2000, as mentioned above (ProMED-mail post 20001028.1877), attempts to confine the pathogen to the site of its initial discovery have unfortunately been unsuccessful. New outbreaks were detected previously also in 2007 and 2014 (ProMED-mail posts 20071102.3559 & 20140901.2738758).

Maps
Canada (with provinces):
http://mapsof.net/uploads/static-maps/Canada_Provinces_and_territories_map.png
Prince Edward Island:
http://homer.ca/images/peimap.gif

Pictures
Potato wart symptoms:
http://3.bp.blogspot.com/-Z2I9uCcxJIk/T4B8yBdYhMI/AAAAAAAAAow/OtwqNyxejak/s1600/potato+wart+disease.jpg,
http://ephytia.inra.fr/en/I/29780/Gale-verruqueuse1 and
http://www.forestryimages.org/images/768x512/0454023.jpg
_S. endobioticum_, microscopy:
https://bugwoodcloud.org/images/768x512/0454042.jpg

Links
Additional news stories:
https://spudsmart.com/potato-wart-found-in-p-e-i-potato-fields/ and
https://potatoes.news/wart-disease-nevertheless-strikes-potato-varieties-with-high-resistance-thanks-to-precipitation/
Information on potato wart disease:
https://gd.eppo.int/taxon/SYNCEN (with country information),
https://planthealthportal.defra.gov.uk/assets/factsheets/pwd.pdf,
https://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=52315,
http://www.inspection.gc.ca/english/plaveg/pestrava/synend/tech/synende.shtml,
http://www.sciencedaily.com/releases/2007/06/070618102406.htm and
https://www.cabi.org/isc/datasheet/52315
Potato wart life cycle:
http://joelfloydillustration.com/images/pathogens/potatowart_lifecycle_jf.jpg
_S. endobioticum_ taxonomy:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=120395
- Mod.DHA]