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Storage Bulletin - October 2012

Publication Date: 
16 October 2012


All levy payers who store should have received a letter about CIPC use in the last week. It contains some very important news about the status of CIPC under the current Stewardship scheme. If you haven’t yet read it, please do so. If you don’t have a copy, please go to the Stewardship webpage at for the full text. A summary of the key points is provided below:

There are important developments in the use of CIPC and a real risk of revocation (withdrawal of the chemical’s approval for use).

The Advisory Committee on Pesticides (ACP) has been monitoring the CIPC Stewardship scheme. There has been a good response by industry but there is still a need to ensure that everyone involved in the use of CIPC is fully committed to the Stewardship Programme and is adhering to best practice. Recent results of official monitoring still include some high residues that exceed the Maximum Residue Level (MRL). This could have potential health implications for some consumers. Both the ACP and the Defra committee on Pesticide Residues in Food (PRiF) are very concerned.

The industry needs to demonstrate it can ensure MRL exceedances will not continue to occur with CIPC. If it fails to resolve these concerns, ACP will have no choice but to recommend regulatory action. This could result in revocation of CIPC.

A loss of CIPC would have serious implications for the potato industry and we all must work together to prevent any further exceedances. There is a customer-driven requirement for compliance with Red Tractor Assurance. From this season, auditing all stores will be a key requirement of this scheme for all CIPC users. Compliance requires crop owners to demonstrate that a check has been carried out to ensure stores are suitable for CIPC use, before any application is carried out. Download a checklist from or ask your contractor for a copy — they can’t fill it in for you. Act now so you’re ready before you need CIPC!

Without doubt, once-in-a-century rainfall events have set us all some significant challenges in 2012, to say the least. The impact on agriculture has been widespread and potato storage is no exception. The problems of a late and difficult harvest on top of the turmoil of a troublesome growing season are now really starting to focus the minds of many of you.

Top of the task list when it comes to storage is to dry the crop when it comes into store. To do this it is imperative to get rid of the loose soil as it is simply impossible to drive air through such a densely packed mass, even with forced ventilation systems. This may entail pre-grading crop as it enters storage and, whilst this is common practice in many areas, it could be another step that just has to be taken for those more used to loading directly into boxes, for example. Without it, storage life of crop that is wet or contains rots is bound to be compromised. Soil can hopefully be returned to the field…

Don’t overfill boxes - you need a space between boxes for air (and CIPC) to distribute effectively. Once in the store, it is critical that potatoes are effectively ventilated with plenty of air. This will dry potatoes and, eventually, any caked-on soil. In the current situation, with colder nights ever more prevalent, the important thing is to keep temperatures high enough to cure any skinning or damage caused by mechanical handling, stones, clods etc. and to avoid blowing warm, moist air onto cooler potatoes as this will cause condensation and undo all the good of that initial ventilation.
Remember that as temperatures drop away, the time taken for the potato to form that all-important barrier to disease ingress and moisture loss gets longer (see table).

  • Potato temperature (°C)         Days for initial barrier to form         Days for complete wound healing
  •         5 and below                                          7 – 14                                             21 – 42
  •       10                                                               4                                                   7 – 14
  •       20                                                            1 – 2                                                 3 –  6

Tied in with this is the timing of the first CIPC application. For CIPC to be most effective (this includes minimising the amount required) it must be applied before the break of dormancy, to a dry crop - but once it is applied wound healing will cease. There has been a successful policy of making the initial application during pull-down in recent seasons and, in all but the most extreme cases where crops are at risk of infection, this should continue.

Whilst yields and size are generally down, quality problems that are being reported currently include a high incidence of greening (crops have generally grown high in the ridge due to comparatively easy access to water), growth cracking and hollow heart. The latter requires some pro-active QC to detect it - don’t wait until store unloading to find out! Blight and blackleg are also around and, whilst drier conditions in some areas in recent weeks have helped reduce their impact, where the rain has continued to fall they will remain an active threat to a crop’s suitability for storage.

Some crops this year will inevitably be marginal in terms of their suitability for storage. If a crop has any signs of rot (eg blackleg, tuber blight, pink rot) in it or there is simply no way to force air through it, its condition can change very rapidly so it is vital to inspect the store frequently (daily for the first month). If unforeseen changes are showing up, take corrective action quickly (call Sutton Bridge for advice on 0800 02 82 111) before the crop becomes unsaleable and a difficult year gets worse.

Further information
FREE storage advice 0800 02 82 111 or
CIPC Best Practice information


Seed Industry Event, Crieff, Perthshire, 20 November
 Please see  or call 0247 647 8772 for further information.

Storage Day, Sutton Bridge CSR, Lincs. 29 November, 10am-4pm
in association with Crop Systems and Restrain
A practically-focused day for all growers, store managers and agronomists.
Benefit from the latest research and advice as experts discuss key crop storage challenges and provide guidance on how to get the best from your storage.
BASIS & NRoSO accredited talks, practical displays & demonstrations.
Seminar programme (repeated morning and afternoon):
Adrian Cunnington: Making changes with real impact on storage efficiency
David Hudson: CIPC use under Red Tractor Assurance in 2012
Emma Garrod: Opportunities for storage in field vegetables
Panel discussions with specialists from leading fresh and processing markets
Submit your questions to these Question Time-style debates.
Potato disease clinic - learn how to identify common diseases and disorders. Bring your own samples!
Trade stands. All the leading storage specialists will be on hand. A few places are still available.
EXTRA - Join us at our Industry Reception in King’s Lynn with guest speaker Nick Tapp
(Head of Agri-Business, Bidwells) on 28 November, 6 - 8pm.
Free registration now.
See the event webpage at or call 01406 351444 for more details.


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