PI-009: Seed Potato Tuber Inspection
Appendix 1: Standards for Tubers – Seeds Regulations Part II

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Table 1: Standards for tubers as stated in the Seeds Regulations Part II.
Disease or Defect Tolerance by Count
at Shipping Point
Tolerance by Count at Destination
Soft rot or wet breakdown 0.1 % 0.5 %
Dry rot, including late blight 1.0 % 1.0 %
Scab and Rhizoctonia combinedTable Note 7
  • (a) light
  • (b) moderate

10.0 %
5.0 %

10.0 %
5.0 %

Stem-end discolouration due to top-killing, frost, heat or drought, with penetration from 6 mm to 13 mm 4.0 % 4.0 %
Malformed and damage 2.0 % 3.0 %
Total number of diseases and defectsTable Note 8 5.0 % 5.0 %

Table Notes

Table Note 7

The total of the combined light, and combined moderate Scab and Rhizoctonia categories must not exceed 10%. No severe Scab or Rhizoctonia is allowed.

Return to table note 7 referrer

Table Note 8

The total of combined tolerances for diseases and defects (not including light scab, light Rhizoctonia and stem-end discolouration), shall not exceed 5% of the total number of tubers in the lot.

Return to table note 8 referrer

Table 2: Describes the conditions of tubers and the tolerance by count of each
Condition Tolerance by Count
Tubers that are not firm 2.0 %
Outgrown sprouts (exceeding 20 mm) 10.0 %
Pressure bruises 5.0 %
Oversize and undersize 5.0 % by weight
Table 3: Describes the conditions of tubers and the tolerance by count of each
Varietal Mixture Tolerance by Count
Nuclear 0.0%
Pre-Elite 0.0%
Elite I 0.0%
Elite II 0.0%
Elite III 0.05 %
Elite IV 0.1 %
Foundation 0.2 %
Certified 0.5 %

Note: Descriptions and tolerances are for reference only; refer to Seeds Regulations Part II for complete information

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