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The Seed Potato Certification Authority is meeting on 16th August to consider some rule changes.  As part of that discussion the Authority is keen to obtain the views of growers.


Proposed rule changes to be discussed include:

  • Introduction of a tolerance for Liberibacter symptoms.
  • Rules allowing rejection of part seed crops.
  • Audit and approval of tissue culture and minituber production facilities.


There will also be discussion led by visiting seed potato inspector, Willem Schrage, a visiting seed potato inspector from the USA.  Willem has recently retired from a long career inspecting seed crops in the Netherlands, Canada, and the USA.  We think his insights will be very valuable for seed growers and inspectors.  Willem is being hosted by Potatoes NZ and will be travelling with his wife Gail.  They will be in Canterbury from Sunday 14th to Wednesday 17th, and then in Pukekohe for the Agronomists’ forum on Thursday 18th.

Details of Proposed Changes:

At the 6 April meeting of the Seed Potato Certification Authority several changes to the rules were proposed.  The Authority is seeking your feedback on these proposed rule changes before they are implemented for next season.


If you are unable to attend the meeting but wish to make a comment on the proposed rule changes, please contact the Secretary (Stephen Ogden at or a member of the Authority.

1.  Liberibacter.  It is proposed that a tolerance for Liberibacter be introduced for the coming season.  In the last season the Authority asked inspectors to note the level of Liberibacter symptoms in seed potato crops.  Overall the inspectors suggested that the incidence in crops was not more than 0.2%.  It is therefore proposed that the Liberibacter tolerance will be the same as the virus tolerance for each generation.

2.  Rejection of parts of a seedline.  Authority members were recently asked to consider a situation where an inspector had passed a portion of a registered crop and rejected another portion.  The members agreed with the recommendation to accept the inspector’s decision and to consider a rule change to clarify the circumstances when this was acceptable.  The rules do not currently allow for a seedline to be separated and a portion excluded.  However, this has been done in the past and is allowed in many overseas schemes.  The Authority has proposed a rule change to allow this.


3.   Tissue culture and mini-tuber production facilities.  The Authority has required that all registered facilities producing tissue culture and mini-tubers are audited and approved as meeting the requirements specified in the rules.  It is proposed that in October the rules are changed to require that only material from audited and approved facilities may be registered into the seed scheme.  One facility has already been recommended for approval and two others are well on their way to being approved.