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Crops in store

25 August 2011

The cold winter weather creates a challenge as temperature differences between the crop in-store and external ambient conditions extend. This month’s Storage Bulletin from Sutton Bridge Experimental Unit (SBEU) has essential advice on how to avoid wet crops by controlling condensation levels to ensure crop quality is maintained.

Wet crops can become a real issue at this time of year, as cold weather can result in structural condensation on the roof – even where insulation levels are good. This is purely a result of the extended temperature difference across the structure combined with the naturally high humidity of the potato storage environment. Structural condensation invariably results in the roof 'dripping' and as soon as this causes the crop to get wet, then there is cause for concern. If you have roof space heating installed, all the better. But, if not, take action to avoid wetting by ensuring good ventilation of the roof area. You can even resort to gentle heating, if necessary, to reduce the humidity of the roof air a little but not enough to significantly heat the crop.

 Also, in periods of very cold weather, as we have been experiencing recently, make sure that any leaks in the store structure are sealed up well. Cold air combined with high winds can quickly chill any crop in the line of a draught. Take care with flushing as low external air temperatures will affect fry colours - you may wish to blend external and recirculated air manually if your system doesn't do this automatically for you. Remember to maintain regular inspections and sample and assess crops in the way your customer routinely keeps a check on quality. Look out for any signs of a change on crop condition in stores which have marginal insulation levels; quite a lot of temporary stores could fall into that bracket this year and be at risk if cold temperatures persist.

 Also watch out for wetness if you are planning to add a dose of CIPC, as this could result in uneven distribution of the chemical. To combat the risk, recirculate extensively before treatment; don't skimp on this as merely moving warm moist air from the roof space to the base of the store could make things worse. Keep the fans running until there is a uniform crop condition throughout the store - then go in with the fogger.

 The industry Code of Practice for the use of CIPC is available online at The guide provides further information on effective CIPC use. If you require a hard copy, please contact SBEU on 0800 02 82 111 or email

New sprout suppressant gains experimental permit
Xeda, a French agrochemical company, has received a provisional approval from the UK's Chemicals Regulation Directorate for its Spearmint Oil potato sprout suppressant. Spearmint Oil is Annex 1 listed in the EU. Efficacy trials on the product, called Biox-M, were carried out at SBEU in 2008/9 and the product has now gained approval in Belgium. 

 Biox-M is contractor-applied using proprietary, electric fogging equipment and is being marketed in the UK by Juno (Plant Protection) Ltd. Although the approval date precludes exclusive treatments, it is understood that some stores will be treated with Biox-M this season.

Forthcoming events

LAMMA 2010
Wednesday 20th & Thursday 21st January – visit the Sutton Bridge stand (no 941, Hall 9) at the UK's biggest agricultural machinery show held at Newark Showground, Notts. See or call 0845 331 6123.

Fruit Logistica 2010
AHDB Potatoes will be making its debut at this huge event held in Berlin from February3rd to 5th. We're on Stand B17 in Hall 3.2. See

PCL Winter Forums
The AHDB Potatoes will be holding these over a three day period in Huntingdon, covering  Blight, Soils & Water and Energy on February 9, 10 and 11 respectively. As well as benefitting from technical updates on each day, there is the chance to join in strategy discussions where future parameters for R&D and knowledge transfer will be considered.

 The Blight Forum’s keynote speaker is Paul Birch, who has been involved in mapping the blight genome. At the Soil & Water event, Mark Stalham of Cambridge University Farm will talk about the soil/water interaction and its effects on disease control, quality and yield.

 At the Energy Forum, SBEU's Adrian Cunnington will give an update on work assessing energy use in potato stores and Tim Pratt, Technical Director of Farm Energy will concentrate on the Feed in Tariff, renewable heat incentives, carbon reduction commitment and how to make money from them. Also Simon Christian, project manager of Biograss Greenfinch Ltd, will give the low-down on setting up an anaerobic digestion plant.

PCL Store Managers’ Course
Our annual two day training course on store management will be held on March 16th to 17th at Boroughbridge in Yorkshire. A certificate is supplied on successful completion of the course. Call 01406 351444 to request a booking form and full details or visit

 Finally, best wishes for a Merry Christmas and a Happy New Year to all our Storage Bulletin subscribers.

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