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Storage Bulletin - August 2015

Publication Date: 
18 September 2015

Storage Bulletin - August 2015

New CIPC labels for 2015/16 released

Further statutory product label changes to chlorpropham (CIPC) were announced in July. CIPC is an essential tool to control sprouting and is applied to about 2 million tonnes of potatoes stored each year by around 1,000 growers.

New, lower application rates for CIPC have now been approved. A gradual annual reduction in CIPC total dose was requested by the companies that hold the approvals for formulations as part of the CIPC stewardship process to ensure compliance with the Maximum Residue Level (MRL) of 10 mg/kg.

For the 2015-16 season, new statutory limits on total dose rates, approved by Chemicals Regulation Directorate (CRD) are 30 grams/tonne for the fresh market and 50 g/t for processing (including fish & chip shop supplies and peeling). The latest time of application is 14 days before removal from store for sale or processing and is also a statutory requirement.

Stewardship best practice, in-line with Red Tractor Farm Assurance and endorsed by the NAAC Applicator Group, permits just one application of up to 16 g/t in cold stores. This applies to all stores to be held below 5°C but application should be made early in storage during pull-down, before the temperature is decreased below 7°C. The lower dose is because the rate of CIPC residue decline is much lower at cold temperature.

Do not store non-target crops such as wheat and onions in stores which have been treated with CIPC.

Summary of Stewardship best practice for CIPC use, including new statutory conditions:

For further information go to

Best practice guidelines for CIPC use in box stores

Good progress has been made lately within AHDB Potatoes’ programme of trials on CIPC use in box stores. This has been reviewed by the CIPC Stewardship Technical Working Group and has increased the confidence with which recommendations can be made for store improvements to maximise performance and lower the risk of MRL exceedance.

CIPC is best applied to a location where it can enter the pallet slots quickly and easily without filling the roof space. Using a covered plenum has been an important part of best practice recommendations over the past three years and our research has shown that the risk of high residues is reduced if CIPC isn’t allowed to settle on to the top surface of the potatoes before it has had chance to move through the crop.

Most importantly, measures to enhance full air recirculation around the store will, with few exceptions, improve CIPC distribution; it is best if this air movement can be relatively slow. This means that, for standard ‘overhead throw’ stores, the addition of an air divider curtain or a suction plenum will increase airflow in the pallet slots and, when used with active ventilation, such as a slow-speed fan, will help to eliminate short circuits and distribute the CIPC fog more evenly than before. (This is akin to the circulation which is recommended best practice in bulk stores).

Positively ventilated box systems such as letterbox or Aspire-type lateral flow designs have also performed well.

Slow speed recirculation can often be achieved – as in bulk stores – by fitting an inverter/VFD to the fan. Fridge coils must be bypassed when recirculating CIPC.

However, some additions can disrupt the uniformity of air movement and are less beneficial. Examples might include the use of foam bungs which significantly increase the back pressure on circulation, or roof fans which can ‘jet’ across the store and skew the air flow.

Trials are continuing in six commercial stores in 2015/16 to further refine best practice.

Disease - watch out!

The very warm but wet weather of recent days will inevitably increase the risk of disease development and, in these conditions, crop status can change very quickly. Keep an eye out for the development of Alternaria, late blight and ‘warm weather’ rots, such as pink rot. There is also a heightened risk of bacterial infection or even breakdown to soft rot, especially if crops have become waterlogged for any time, which threatens storage quality.

For more information and advice on disease control, call SBCSR on 0800 02 82 111.

Can you help us with our R&D?

Sutton Bridge Crop Storage Research recently won significant funding from Innovate UK, as part of a large cross-industry consortium, to work on a computer-based modelling tool to optimise store airflow and fogged sprout suppressant use.  We want to recruit a young person, ideally with training in agricultural and/or software engineering, to join our team for up to two years to help us deliver this important work.

We are also looking to fill a short term research contract for approximately 9 months addressing control of bacterial breakdown. If you are interested in either position or know someone who might like to work at the cutting edge of storage R&D, please contact Adrian Cunnington or Glyn Harper on 01406 351444 or

Oliver Statham   1941-2015

It was with great regret that we recently learned of the death, after a long illness, of our former colleague, Oliver Statham. Oliver was Machinery Officer for PMB and BPC, and contributed significantly to the development of the Sutton Bridge site in the 70s, 80s and 90s. Stores he helped to design back in 1980 included features such as reverse-cycle defrost, variable pitch main fans and some of the earliest electronic zonal control systems – all well ahead of their time. He was, however, perhaps best known for his role as organiser of many highly successful, Working Machinery Demonstrations held around that period.

Our sympathies are with his wife Anne, his family and friends.

Forthcoming events

SPot Farm Walk, 11 September, Staffs

AHDB Potatoes has the final Farm Walk of the year coming up at its Strategic Potato (SPot) Farm on 11 September, 9am-11am at W B Daw & Son, Bellamour Lane, Colton, Rugeley, Staffordshire, WS15 3JR.

To register go to:

BP2015 Exhibition & Industry Dinner: 12/13 November, Harrogate

The major industry biennial gathering will be based at a new venue: Harrogate International Centre.

A more extensive seminar session and larger industry dinner are planned around the now customary trade exhibition. Book now at


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