Minimum tolerances
(Updated 16 July 2019)
Some countries have particular phytosanitary requirements for the presence of pests, diseases, faults and disorders in the potatoes being presented for marketing.
However, where an importing country does not specify a phytosanitary requirement or condition for a specific disease, pest, type of damage or defect that is listed in Scottish regulations, the Scottish minimum export tolerances for tuber inspections are applicable and must be met before a Phytosanitary Certificate can be issued for export of the tubers.
Seed potatoes - minimum tolerances
The tolerances below will be applied unless the importing country's requirements are stricter.
| Disease, pest, damage or defect | Individual tolerance 1 | Individual allowable surface area cover | Group tolerance 1 | Collective tolerance groups II, III & IV |
|---|---|---|---|---|
| GROUP I | NIL | |||
| Wart disease | NIL | - | ||
| Potato tuber eelworm | NIL | - | ||
| Potato cyst nematodes | NIL | - | ||
| Ring rot | NIL | - | ||
| Brown rot | NIL | - | ||
| Potato tuber moth | NIL | - | ||
| Potato Spindle Tuber Viroid | NIL | - | ||
| Colorado beetle | NIL | - | ||
| GROUP II | 0.2% | |||
| Rots including Blight | 0.2% | - | ||
| Blackleg/bacterial soft rot (Pectobacterium spp.) | 0.2% | - | ||
| Blackleg/bacterial soft rot (Dickeya spp.) | 0.0% | - | ||
| Gangrene/Dry rot/Wet rot | 0.2% | - | ||
| GROUP III | 1.5% | |||
| Skin spot | 0.5% | 12.5% | ||
| Black scurf | 1.5% | 12.5% | ||
| Common scab | 1.5% | 12.5% | ||
| Powdery scab | 1.5% | 12.5% | ||
| GROUP IV | 3.0% | |||
| Externally blemished or atypically shaped tubers 2 | 1.0% | - | ||
| Superficial necrosis by PVY | 0.1% | - | ||
| External necrosis by other viruses | 2.0% | - | ||
| 4.7% | ||||
| GROUP V | 0.5% | |||
| Dirt or other extraneous matter | 0.5% | - |
1 Tolerances are by weight
2 Includes tubers wrinkeled or dehydrated due to silver scurf (Helminthosporium solani)
Ware potatoes - minimum tolerances
The tolerances below will be applied unless the importing country's requirements are stricter.
| Disease, pest, damage and defect | Tolerance 1 | Allowable surface area cover |
|---|---|---|
| Rot diseases blight, dry rot, pink rot, watery wound rot, bacterial rots, blackleg, pit rot, gangrene, frost |
1% |
|
| Surface diseases skin spot, black scurf, common scab, powdery scab, silver scurf |
2% | 12.5% per disease |
| Virus diseases and internal defects | 2% | |
| Damaged and misshapen tubers | 1% | |
| Greening | 1% | 12.5% 2 |
| Aggregate of the 5 groups above | 6% | |
| Soil and other extraneous matter | 0.5% |
1 Tolerances are by weight
2 No surface area cover allowed if the greening is more than skin deep