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Ware and seed growers now covered by PCN legislation

1 August 2011

All growers should be aware that the PCN Directive that came into effect in July 2010 covers all potatoes for replanting and not just certified seed, says Mark Prentice.

The new EU PCN directive has implications for ware land and farm-saved seed as well as certified seed. Mark Prentice, AHDB Potatoes head of seed and export, emphasises that all growers should take the time to understand the implications of the change in legislation and what it means for them.

He also mentions that there are differences in the way the Scottish Government and Fera have implemented the directive, advising growers who have any concerns to contact their local inspectorate.

Ware Survey
Mark Prentice, AHDB Potatoes head of seed and export, points out that as a result of the PCN Directive that became law in 2010, 0.5% (600-700) hectares of land used for growing ware crops will be selected annually for PCN testing.

“Both Fera and the Scottish Government need to conduct surveys to comply with the directive,” explains Mark. “As they must notify the EU with findings before April each year, potato fields will be selected post-crop for testing by March.

“This seems like a pragmatic approach. The ware grower has the maximum time to ensure all the crop from a selected field is marketed before the results are known, and any action is taken. Any positive findings will mean that the land will be placed under a control programme and if there are any remaining potatoes in store these will need to be marketed under ‘Notice’.”

Control Programmes
One aspect of the new regulations that has not changed is that any field that is officially tested and comes back positive for PCN will be officially registered as infested with PCN, but a new element is that it will be subject to a Control Programme.

 “Previously, other than for potatoes lifted early, the use of resistant varieties was stipulated, which for Globodera pallida was very difficult and really restricted the use of PCN-infested land,” explains Mark.

“However, options have been freed up and are now more flexible. As long as growers can demonstrate that actions will ‘suppress’ PCN over time, there is now no restriction on variety. In effect, varietal resistance is now one part of a wider programme of measures, including rotation and nematicides.

“This is going to result in a more case-by-case approach between the grower and the authorities. This may mean more initial work for the grower, but potentially frees up the land to remain in viable ware production. Growers will now be able to continue cultivating varieties demanded by the market.”

Mark explains that all the grower will have to do is liaise with the local inspectorate to develop a control programme that can demonstrate that their future action will ‘suppress’ (rather than not increase) the level of PCN in that field. Fera and the Scottish Government have each published guidance on the process, including advice on the range of options available.

“The authorities will rely on the agreed Control Programme to demonstrate that PCN is being suppressed,” continues Mark. “Clearly this programme will need to rely on sound science and best practice to demonstrate it is sustainable.”

There will be no automatic follow up tests on this, unless the grower wishes to try and have the land declared free from PCN after the minimum statutory six year gap.

Mark advises any growers who have land that is officially registered as infested to speak to their local inspectorate, taking the opportunity to engage in dialogue with them and come up with an appropriate plan for each field.

For options moving forward, growers should also contact their agronomist or farm adviser.

AHDB Potatoes are reviewing historic research and PCN modelling software, to help growers and agronomist develop Control Programmes where appropriate. New research is also looking to help fill in gaps in knowledge, including resistance ratings for new varieties.

 Mark emphasises that the official control programmes only affect land that has been tested by the government and registered as infested.

Farm-saved seed
The new Directive stipulates that a pre-planting test needs to be carried out for all potatoes for planting, but there is a derogation for  farm-saved seed which is to be replanted within the same  ‘place of production’. However, there are differences between how this is being implemented in Scotland and England & Wales, Mark reminds growers.

In Scotland, the place of production is defined by the ‘farm code’. Where production units have been amalgamated they will need to be within the same parish or be contiguous across a parish boundary. Growers who are planning to produce farm saved seed, and who may need to move it away from ‘the place of production’, should speak to their local area office about having the land tested for PCN before planting.

It is important to remember that any positive finding will result in the field being subject to a control programme, which includes a ban on using it for any seed production, including farm saved seed.

However, in England and Wales, farm-saved seed is allowed to be moved to any land in the same ownership or operational management. In effect, this is the status quo, which was agreed following a consultation on this issue and in response to the different PCN situation in England and Wales. However, this is of some concern for PCN spread given the large area over which many businesses now operate. 

“Best Practice would indicate that the status of PCN should be determined if farm saved seed is to be moved over any distance, and Fera has produced some guidance on this” he states.

Seed potatoes
Harmonisation of sampling rates across the EU presents both benefits and challenges to growers, comments Mark.

“As the new ‘reduced’ sample rate is four times as great as previously, there is potential for a higher rate of PCN detection,” he says.

“However, all growers will have the scope to determine the size of the field they have sampled. This has both advantages and disadvantages.

 “In Scotland where charging has been introduced, it will work out cheaper if farmers choose to include more land in each parcel sampled. However, if PCN is detected, a larger area will have failed and be subject to restrictions. The devil is in the detail, and it is important that growers consider this carefully.”

Where a grower is faced with an official positive result, there is a decision to make about whether it will be possible to eradicate PCN, and for it to be brought back in to seed production. This will depend on many factors, not least the population level of PCN found.

Mark advises seed growers with any positive official test to discuss the possibilities of PCN eradication with the authorities and their agronomist.

It will be a minimum of 6 years before the grower will be able to request another test to try and have it declared PCN free.

For more details and guidance on the Scottish legislation please visit

For more details and guidance on the English and Welsh legislation, and additional factsheets, click here.

For further information and advice please email Mark on

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