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Storage Bulletin - September 2010

Publication Date: 
20 September 2010

This season's potato crop is later than usual for many people, and with wet weather adding further delay, it is going to be important to be vigilant in assessing quality entering store. As the harvest moves later into the autumn the risk of disease generally increases, especially if this is accompanied by wet field conditions.

Disease levels over the summer have tended to be low but at Sutton Bridge we have seen the early signs of rots in samples brought in over the last couple of weeks, ranging from lenticellular breakdown (akin to pit rot) to tuber blight.

On a more positive note, blemish disease levels have been reduced by the short growing season, albeit at the expense of yield. But the relatively warm and wet conditions of the last month will have been good conditions to encourage many of the bacteria and fungi and, although ambient temperatures are now falling, they are still more than high enough to encourage spread. So do keep an eye out for the tell-tale signs of something going awry - such as soil clinging to a few tubers (associated with pink rot) or irregular dark patches on the tuber skin, which can highlight a problem with blight.

Be prepared to blow plenty of air through the crop as soon as it can be practically achieved. Take specific steps to ensure air can circulate through the potatoes but without short circuiting back to the fan. If you have positive ventilation systems such as letterboxes, use them! It is also important to manage temperatures as crops go into store so there is no more than 4-5C difference between the incoming crop and the crop in store. Failure to manage temperature differentials almost always leads to condensation which will quickly undo any benefit of drying and result in the spread of disease.


With the continued need to minimise our use of post-harvest chemicals, it is important to take on board the latest thinking on the use of CIPC.

This includes timing the first application for optimal control and there is increasing evidence that the first application should, for all but the most dormant of varieties, be put on around 14 days after store loading. There is more benefit to be gained from putting on the CIPC at the right time than the right temperature, so approval holders are keen to see the first application go on in a timely fashion, even if this means making the application with crop temperatures as high as 10 or 12C.

The only exception to this approach could be needed in skin spot susceptible varieties in situations where temperatures fall below, about 8C. Here adequate curing needs to have taken place before the CIPC goes on.

If you are storing in bulk, there is a mountain of data building up to support the use of inverters (speed controllers) on fans to assist with application. The technique provides more uniform application (and therefore residues), has the advantage of lowering running costs for many fans and can even reduce the need for chemical use which helps to provide an even more  rapid payback on the investment.Visit and for further information.
One key issue to consider if you are contemplating CIPC use is whether your store is actually up to the job. Under the auspices of the CIPC Stewardship scheme, a new checklist has just been launched to allow you to run a self-check on your store before it is treated. This is a stepping stone towards a more rigorous requirement for assessment which will be needed under Assured Produce in due course. So why not get a head start, download a form from and run the check on your store now? It takes less than 10 minutes to complete!

Visit and for further information.


Sutton Bride has run a Storage Discussion Group for levy payers and their agronomists for several years now, which has met three times a year (twice at SBCSR and once off site) to discuss topical matters. The format for the Group meetings will be reviewed in the coming months so, if you are interested in joining and contributing to the debate, please drop a line to Adrian Cunnington ( and we will send you more information.


Many thanks to all our bulletin subscribers who came along to our recent Storage Event at Sutton Bridge CSR. We felt it was a very well supported day where delegates could get to focus on many aspects of storage. We were delighted to see as many as 250 people on site to listen to the presentations and share the opening of our new stores by Lord Taylor of Holbeach with us.

Email us at if you'd like to receive an electronic copy of the presenations.


Don't forget the PCL Seed Industry Event which takes place on 26 October 2010 at Crieff Hydro. The programme includes a storage workshop by Adrian Cunnington of SBCSR. Visit for more information.

Also, those of you looking for some intensive store management training - or simply a refresher - may wish to make a note of the provisional dates for the next residential PCL Store Managers' Course, scheduled for 17/18 February 2011 at Sutton Bridge and King's Lynn. If you wish to receive full details when they become available in November, please drop a line to Kate Balloch at SBCSR ( or call her on 01406 359418.

Finally a date for your long term diary. The World Potato Congress will be held in the UK for only the second time in its history when it is hosted by AHDB Potatoes in Edinburgh from 27-30 May 2012.

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