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

Date: Wed 16 Mar 2022
Source: Farmers Weekly [summ. Mod.DHA, edited]
https://www.fwi.co.uk/arable/potatoes/disease-risk-from-illegal-potato-seed-cannot-be-overstated


Up to 1000 tonnes of Agria variety ware potatoes have been imported into the UK and supplied as uncertified seed tubers in eastern England. The Animal and Plant Health Agency (Apha) said it was aware of at least one operator attempting to circumvent plant health rules. They will pursue robust action against growers who plant illegal potato seed, as well as their suppliers, for breaching biosecurity. They are carrying out general and targeted surveillance to ensure compliance. Farmers should ensure any seed stocks are properly certified and from a reputable source.

Defra (Department for Environment, Food & Rural Affairs) said pests and diseases known to occur in Europe -- such as ring rot, brown rot, and zebra chip -- pose a serious threat to the British potato industry. Some operators are importing ware potatoes, particularly of varieties that are unavailable or difficult to grow, as seed tubers. The biosecurity risk of such practices cannot be overstated.

[byline: Johann Tasker]

--
communicated by:
ProMED

[Farm saved or other uncertified potato seed tubers are known to carry a serious biosecurity risk. They pose a threat to crop production and have frequently been reported as sources of disease outbreaks in different countries. Use of certified pathogen-free planting stock is considered vital for all cultivated species, to prevent incursions of both new pathogens and additional, potentially more severe strains of pathogens already present in an area.

The diseases mentioned above are:
1. Bacterial ring rot, caused by _Clavibacter michiganensis_ subsp. _sepedonicus_ with up to 50% yield losses; many solanaceous species (such as tomato, aubergine) are also susceptible.
2. Brown rot (also called bacterial wilt), caused by _Ralstonia solanacearum_ race 3 (biovar 2, adapted to cooler temperatures) or race 1 (prevalent in warmer areas); yield losses are mostly caused by tuber rotting.
3. Zebra chip, caused by _Candidatus_ Liberibacter solanacearum; the pathogen has also been associated with yellowing diseases of other solanaceous crops and some crops in the family Apiaceae (such as carrots).

For more information on these diseases see previous ProMED posts in the archives.

Maps
UK:
https://www.worldometers.info/img/maps/unitedkingdom_physical_map.gif and
https://promedmail.org/promed-post?place=8702126,279
Europe, overview:
http://www.edinphoto.org.uk/0_MAPS/0_map_europe_political_2001_enlarged.jpg

Pictures
Potato ring rot symptoms via:
http://www.forestryimages.org/browse/subimages.cfm?sub=11051
Potato brown rot symptoms:
https://projects.ncsu.edu/cals/course/pp728/Ralstonia/potato_field.gif
Zebra chip of potato:
https://agriculturaemar.com/wp-content/uploads/2017/01/zebra-chip-02.jpg

Links
Additional summary:
https://www.freshplaza.com/article/9410545/disease-risk-from-illegal-potato-seeds-cannot-be-overstated/
Information on potato ring rot:
https://gd.eppo.int/taxon/CORBSE
Brown rot of potato:
http://www.cabi.org/isc/datasheet/45009
Potato zebra chip disease:
https://doi.org/10.1007/s10658-010-9702-1
Bacterial taxonomy via:
https://www.uniprot.org/taxonomy/2
DEFRA:
https://www.gov.uk/government/organisations/department-for-environment-food-rural-affairs
- Mod.DHA]

See Also

2021
---
Liberibacter solanacearum - Kazakhstan: interceptions 20211103.8699421
2020
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Ralstonia, potato & tomato - Germany: (BY) alert 20201222.8037126
2019
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Liberibacter solanacearum - Finland, Germany, USA: new haplotypes 20190226.6336285
Liberibacter solanacearum - Tunisia (1st report), Finland 20190213.6311149
2018
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Wart & brown rot, potato - Georgia, Russia: interceptions 20180327.5712463
2017
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Liberibacter solanacearum, potato - Spain: (CB) 20170802.5222241
Brown rot, potato - Switzerland: alert 20170227.4868480
Brown rot, potato - Poland 20170213.4834454
2015
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Bacterial ring rot, potato - Russia: (northern) 20151113.3787802
2014
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Bacterial ring rot, potato - Europe: (France, Slovakia, Finland) 20140611.2533363
and additional items on potato diseases in the archives

Website: http://www.isid.org

Published: March 22, 2022