# The Seed Potatoes (Scotland) Regulations 2015, Paragraph 5: Allowable surface area cover

Extent: S

(1) This paragraph applies, for the purposes of regulation 16(1) and (3), to seed potatoes to which Table II, III (a), (b) or (c) or IV applies.
(2) Subject to sub-paragraph (3), an authorised officer may deem a potato in any sample of seed potatoes to which this paragraph applies not to be affected by a disease in Group III, specified in column 1 of the Table in relation to a potato of that grade when, in the officer's opinion—
(a) the surface area of the potato affected by the disease is less than the percentage surface area in the entry corresponding to the disease in column 5 of the Table; and
(b) the potato has at least two eyes at the rose end wholly unaffected by the disease.
(3) Sub-paragraph (2) does not apply when the disease Powdery Scab (Spongospora subterranea (Wallr.) Lagerh) takes its cankerous form.
TABLE I
GB GRADE PBTC PRODUCED IN SCOTLAND
Column 1Diseases, pests, damage and defects
Column 2Individual Tolerances
Group I
Potato Wart Disease (Synchytrium endobioticum (Schilb) Perc.)
Nil
Potato Tuber Eelworm (Ditylenchus destructor Thorne)
Nil
Potato Cyst Nematode (Globodera spp. infesting potatoes)
Nil
Ring Rot (Clavibacter michiganensis subsp.sepedonicus (Spieck & Kotth) Daviset al.)
Nil
Brown Rot (Ralstonia solanacearum (Smith) Yabuuchiet al.)
Nil
Potato Tuber Moth (Phthorimaea operculella (Zell))
Nil
Potato Spindle Tuber Viroid
Nil
Colorado Beetle (Leptinotarsa decemlineata (Say))
Nil
Candidatus Liberibacter solanacearum Liefting et al., [LIBEPS
Nil
Group II
Blackleg (Pectobacterium spp.)
Nil
Dickeyaspp.
Nil
Rots including Wet Rot but other than rots specified in Group I
Nil
Frost damaged tubers
Nil
Group III
Skin spot (Polyscytalum pustulans (Owen & Wakefield) Ellis)
Nil
Black scurf (Rhizoctonia solani Kühn)
Nil
Common scab (Streptomyces spp.)
Nil
Powdery scab (Spongospora subterranea) (Wallr) Lagerh.f.sp.subterranea)
Nil
Group IV
External blemishes or tubers other than diseased tubers whose shape is atypical for the variety
Nil
Superficial necrosis caused by strains of Potato Virus Y
Nil
Shrivelled tubers
Nil
Group V
Dirt or extraneous matter
1.0%
TABLE II
GB GRADE PB PRODUCED IN SCOTLAND
Column 1Diseases, pests, damage and defects
Column 2Individual Tolerances
Column 3Group Tolerances
Column 4Collective Group Tolerances
Column 5Allowable % surface area cover
Group I
Potato Wart Disease (Synchytrium endobioticum (Schilb) Perc.)
Nil
Potato Tuber
Nil
Eelworm (Ditylenchus destructor Thorne)
Potato Cyst Nematode (Globodera spp. infesting potatoes)
Nil
Ring Rot (Clavibacter michiganensis subsp.sepedonicus (Spieck & Kotth) Daviset al.)
Nil
Brown Rot (Ralstonia solanacearum (Smith) Yabuuchiet al.)
Nil
Potato Tuber Moth (Phthorimaea operculella (Zell))
Nil
Potato Spindle Tuber Viroid
Nil
Colorado Beetle (Leptinotarsa decemlineata (Say))
Nil
Candidatus Liberibacter solanacearum Liefting et al., [LIBEPS
Nil
Group II
Blackleg (Pectobacterium spp.)
Nil
0.2%
}
Dickeyaspp.
Nil
}
Rots, other than rots specified in Group I
0.2%
}
Frost damaged tubers
0.2%
}
Group III
Skin spot (Polyscytalum pustulans (Owen & Wakefield) Ellis)
0.2%
5.0%
}
Black scurf (Rhizoctonia solani Kühn)
1.0%
}
6.0%
10.0%
Common scab (Streptomyces spp.)
5.0%
}
33.3%
Powdery scab (Spongospora subterranea (Wallr) Lagerh.f.sp.subterranea)
1.0%
}
10.0%
Group IV
External blemishes or tubers other than diseased tubers whose shape is atypical for the variety
3.0%
3.0%
}
Superficial necrosis caused by strains of Potato Virus Y
Nil
}
Shrivelled tubers
0.5%
}
Group V
Dirt or extraneous matter
1%
1%
TABLE III
GB GRADE S, SE AND E AND TEST AND TRIAL SEED POTATOES
a) GB GRADE S PRODUCED IN SCOTLAND
Column 1Diseases, pests, damage and defects
Column 2Individual Tolerances
Column 3Group Tolerances
Column 4Collective Group Tolerances
Column 5Allowable % surface area cover
Group I
Potato Wart Disease (Synchytrium endobioticum (Schilb) Perc.)
Nil
Potato Tuber Eelworm (Ditylenchus destructor Thorne)
Nil
Potato Cyst Nematode (Globodera spp. infesting potatoes)
Nil
Ring Rot (Clavibacter michiganensis subsp.sepedonicus (Spieck & Kotth) Daviset al.)
Nil
Brown Rot (Ralstonia solanacearum (Smith) Yabuuchiet al.)
Nil
Potato Tuber Moth (Phthorimaea operculella (Zell)
Nil
Potato Spindle Tuber Viroid
Nil
Colorado Beetle (Leptinotarsa decemlineata (Say)
Nil
Candidatus Liberibacter solanacearum Liefting et al., [LIBEPS
Nil
Group II
Dickeyaspp.
Nil
}
Rots, other than rots specified in Group I
0.5%
0.5%
}
(of which Wet Rot)
(0.2%)
}
Frost damaged tubers
0.5%
}
Group III
Skin spot (Polyscytalum pustulans (Owen & Wakefield) Ellis)
0.5%
5.0%
}
12.5%
Black scurf (Rhizoctonia solani Kühn)
5.0%
}
6.0%
10.0%
Common scab (Streptomyces spp.)
5.0%
}
33.3%
Powdery scab (Spongospora subterranea (Wallr) Lagerh.f.sp.subterranea)
3.0%
}
10.0%
Group IV
External blemishes or tubers other than diseased tubers whose shape is atypical for the variety
3.0%
3.0%
}
Superficial necrosis caused by strains of Potato Virus Y
0.1%
}
Shrivelled tubers
1.0%
}
Group V
Dirt or extraneous matter
1.0%
1.0%
b) GB GRADE SE PRODUCED IN SCOTLAND
Column 1Diseases, pests, damage and defects
Column 2Individual Tolerances
Column 3Group Tolerances
Column 4Collective Group Tolerances
Column 5Allowable % surface area cover
Group I
Potato Wart Disease (Synchytrium endobioticum (Schilb) Perc.)
Nil
Potato Tuber Eelworm (Ditylenchus destructor Thorne)
Nil
Potato Cyst Nematode (Globodera spp. infesting potatoes)
Nil
Ring Rot (Clavibacter michiganensis subsp.sepedonicus (Spieck & Kotth) Daviset al.)
Nil
Brown Rot (Ralstonia solanacearum (Smith) Yabuuchiet al.)
Nil
Potato Tuber Moth (Phthorimaea operculella (Zell))
Nil
Potato Spindle Tuber Viroid
Nil
Colorado Beetle (Leptinotarsa decemlineata (Say))
Nil
Candidatus Liberibacter solanacearum Liefting et al., [LIBEPS
Nil
Group II
Dickeyaspp.
Nil
}
Rots, other than rots specified in Group I
0.5%
}
(of which Wet Rot)
(0.2%)
}
Frost damaged tubers
0.5%
}
Group III
Skin spot (Polyscytalum pustulans (Owen & Wakefield) Ellis)
0.5%
5.0%
}
12.5%
Black scurf (Rhizoctonia solani Kühn)
5.0%
}
6.0%
10.0%
Common scab (Streptomyces spp.)
5.0%
}
33.3%
Powdery scab (Spongospora subterranea (Wallr) Lagerh.f.sp.subterranea)
3.0%
}
10.0%
Group IV
External blemishes or tubers other than diseased tubers whose shape is atypical for the variety
3.0%
3.0%
}
Superficial necrosis caused by strains of Potato Virus Y
0.1%
}
Shrivelled tubers
1.0%
}
Group V
Dirt or extraneous matter
1.0%
1.0%
c) GB GRADE E AND TEST AND TRIAL SEED POTATOES PRODUCED IN SCOTLAND
Column 1Diseases, pests, damage and defects
Column 2Individual Tolerances
Column 3Group Tolerances
Column 4Collective Group Tolerances
Column 5Allowable % surface area cover
Group I
Potato Wart Disease (Synchytrium endobioticum (Schilb) Perc.)
Nil
Potato Tuber Eelworm (Ditylenchus destructor Thorne)
Nil
Potato Cyst Nematode (Globodera spp. infesting potatoes)
Nil
Ring Rot (Clavibacter michiganensis subsp.sepedonicus(Spieck & Kotth) Daviset al.)
Nil
Brown Rot (Ralstonia solanacearum (Smith) Yabuuchiet al.)
Nil
Potato Tuber Moth (Phthorimaea operculella(Zell))
Nil
Potato Spindle Tuber Viroid
Nil
Colorado Beetle (Leptinotarsa decemlineata (Say))
Nil
Candidatus Liberibacter solanacearum Liefting et al., [LIBEPS
Nil
Group II
Dickeyaspp.
Nil
}
Rots, other than rots specified in Group I
0.5%
0.5%
}
(of which Wet Rot)
(0.2%)
}
Frost damaged tubers
0.5%
}
Group III
Skin spot (Polyscytalum pustulans (Owen & Wakefield) Ellis)
0.5%
5.0%
}
12.5%
Black scurf (Rhizoctonia solani Kühn)
5.0%
}
10.0%
Common scab (Streptomyces spp.)
5.0%
}
6.0%
33.3%
Powdery scab (Spongospora subterranea (Wallr) Lagerh.f.sp.subterranea)
3.0%
}
10.0%
Group IV
External blemishes or tubers other than diseased tubers whose shape is atypical for the variety
3.0%
3.0%
}
Superficial necrosis caused by strains of Potato Virus Y
0.1%
}
Shrivelled tubers
1.0%
}
Group V
Dirt or extraneous matter
1.0%
TABLE IV
BASIC SEED POTATOES INTENDED FOR MARKETS OUTSIDE THE British Islands
Column 1Diseases, pests, damage and defects
Column 2Individual Tolerances
Column 3Group Tolerances
Column 4Collective Group Tolerances
Column 5Allowable % surface area cover
Group I
Potato Wart Disease (Synchytrium endobioticum (Schilb) Perc.)
Nil
Potato Tuber Eelworm (Ditylenchus destructor Thorne)
Nil
Potato Cyst Nematode (Globodera spp. infesting potatoes)
Nil
Ring Rot (Clavibacter michiganensis subsp.sepedonicus (Spieck & Kotth) Daviset al.)
Nil
Brown Rot (Ralstonia solanacearum (Smith) Yabuuchiet al.)
Nil
Potato Tuber Moth (Phthorimaea operculella (Zell))
Nil
Potato Spindle Tuber Viroid
Nil
Colorado Beetle (Leptinotarsa decemlineata (Say))
Nil
Group II
Dickeyaspp.
Nil
}
Rots including Wet Rot but other than rots specified in Group I
0.2%
0.2%
}
Frost damaged tubers
0.2%
}
Group III
Skin spot (Polyscytalum pustulans (Owen & Wakefield) Ellis)
0.5%
1.5%
}
12.5%
Black scurf (Rhizoctonia solani Kühn)
1.5%
}
4.7%
12.5%
Common scab (Streptomyces spp.)
1.5%
}
12.5%
Powdery scab (Spongospora subterranea (Wallr) Lagerh.f.sp.subterranea)
1.5%
}
12.5%
Group IV
External blemishes or tubers other than diseased tubers whose shape is atypical for the variety
1.0%
3.0%
}
Superficial necrosis caused by strains of Potato Virus Y
0.1%
}
External necrosis (caused by viruses other than Potato Virus Y)
2.0%
}
Shrivelled tubers
2.0%
}
Group V
Dirt or extraneous matter
0.5%

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Source: https://www.legislation.gov.uk/ssi/2015/395/schedule/6/paragraph/5 (the official version)
Page: https://openlegislation.uk/seed-potatoes-scotland-regulations-2015/schedule-6/paragraph-5
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.