# The Seed Potatoes (Wales) Regulations 2016, Part 3: Basic seed potatoes and certified seed potatoes produced in Wales


Column 1
Column 2
Column 3
Column 4
Specified diseases or pests, damage and defects
Individual tolerances
Group tolerances
Collective group tolerances
Group I
Wart Disease (Synchytrium endobioticum (Schlib) Perc)
Nil
-
-
Potato Tuber Eelworm (Ditylenchus destructor Thorne)
Nil
-
-
Potato Cyst Nematode (Globodera species infesting potatoes)
Nil
-
-
Ring Rot (Clavibacter michiganensis (Smith) Davis et al spp sepedonicus (Spieck & Kotth) Davis et al)
Nil
-
-
Brown Rot (Ralstonia solanacearum (Smith) Yabuuchi et al)
Nil
-
-
Potato Spindle Tuber Viroid
Nil
-
-
Colorado Beetle (Lepinotarsa decemlineata (Say))
Nil
-
-
Candidatus Liberibacter solanacearum Liefting et al
Nil
-
-
Candidatus Phytoplasma solani Quaglino et al
Nil
-
-
Group II
Blight (Phytophthora infestans (Mont) de Bary)
0.5%
)
)
Blackleg (Dickeya Samson et al. spp. or Pectobacterium Waldee emend. Hauben et al. spp. or both)
0.5%
)
)
Soft Rots including Watery Wound Rot (Pythium ultimum Trow)
0.5%
)
)
Pink Rot (Phytophthora erythroseptica Pethybridge) and Pit Rot
0.5%
) 0.5%
)
Dry Rot (Fusarium species)
0.5%
)
)
Gangrene (Phoma species)
0.5%
)
)
Frost damaged tubers
0.5%
)
)
Any of these Group II defects that present as a wet rot symptom
0.2%
)
)6.0% for basic seed potatoes and 8.0% for certified seed potatoes
Group III
Skin spot (Polyscytalum pustulans (Owen & Wakefield) M B Ellis)
0.5% except GB grade E, GB grade A and GB grade B grades; 2.0% for GB grade E, GB grade A and GB grade B grades only
)
)
Powdery scab (Spongospora subterranea (Wallr) Legerh)
3.0%
) 5.0%
)
Provided that seed potatoes which have at least two eyes at the rose end that are wholly unaffected and less than one-tenth of whose surface area has been affected are deemed to be unaffected by the disease (except where powdery scab takes its cankerous form)
Group IV
Black scurf as caused by Thanatephorus cucumeris (A.B. Frank) Donk Provided that seed potatoes which have at least two eyes at the rose end that are wholly unaffected and less than one-tenth of whose surface area has been affected are deemed to be unaffected by the disease
5.0%
)
)
Common Scab (Streptomyces species) Provided that seed potatoes which have at least two eyes at the rose end that are wholly unaffected and less than one-third of whose surface area has been affected are deemed to be unaffected by the disease
5.0%
)
)
Group V
External blemishes including damaged tubers or tubers other than diseased tubers whose shape is atypical for the variety
3.0%
)
)
Shrivelled tubers due to excessive dehydration or dehydration caused by silver scurf (Helminthosporium solani)
1.0%
) 3.0%
)
Superficial necrosis caused by strains of potato virus Y
0.1%
)
)
Group VI
Dirt or other extraneous matter
1.0%
-
-

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Source: https://www.legislation.gov.uk/wsi/2016/106/schedule/3/part/3 (the official version)
Page: https://openlegislation.uk/seed-potatoes-wales-regulations-2016/schedule-3/part-3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.