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First potato storage season for new lower CIPC rates

Publication Date: 
18 September 2017

In agreement with ‘Step Down’ processes, new lower application rates for CIPC use for the coming season (2017-18) have now been approved.

Mike Storey, AHDB’s Head of Resource Management and Chair of the Industry CIPC Stewardship Group, said: “As part of the CIPC Stewardship process, requests are made by companies that hold approvals to formulate new rates, which helps ensure compliance with the Maximum Residue Level (MRL of 10 mg/kg.”

For the 2017-18 season, the new statutory limits for total dose, approved by Chemicals Regulation Directorate (CRD) are 36 grams/tonne for processing (including fish & chip shop supplies and peeling) and 24 g/t for the fresh market. The maximum individual dose is reduced to 12g/tonne. The latest time of application is 14 days before removal from store for sale or processing and is a statutory requirement.

Additionally, Stewardship best practice, endorsed by the NAAC’s CIPC Applicator Group and Red Tractor Farm Assurance, continues to allow just one application of up to 12 g/t in cold stores as CIPC residue declines more slowly at low temperature.  This applies to all stores that will be held below 5°C. This application should be made early in storage during pull-down, before the temperature is decreased below 7°C, for maximum efficacy.

Summary of Stewardship best practice for CIPC use in 2017/18:

No fan, no fog​

Critically for 2017, fans will be required, with CIPC needing to be actively recirculated at low speed during the application process, and until the fog has cleared. CIPC applications will not be made if fog is not able to be recirculated. This is for residue control purposes as well as efficacy at the lower dose rates.

In stores with positive ventilation (bulk stores and some box stores), active recirculation will mostly be achieved by fitting a Variable Frequency Drive (VFD) and using the store’s ventilations system. In overhead throw box stores active recirculation can be brought about using an air separator to create an ‘open suction’ system or plenums. Different approaches are detailed in the PICSG’s CIPC Application: A Store Owner’s Guide, which is available at

It is recommended that users consult their NAAC CIPC Applicator to discuss this requirement now to ensure that, if steps have not yet been taken to modify stores, applications can still be made this season.

Finally, it is important to note any food, feed or seed, other than ware potatoes, should not be held in stores, which have been treated with CIPC. This is because CIPC penetrates the store fabric and is then re-released risking damaging seed and contaminating food and feed.  The Maximum Residue Level for CIPC in anything other than potatoes is the limit of detection (around 0.01mg/kg).

More information is available in the Store Assessment of the Red Tractor Combinable Crops protocol at

For further information, see the PICSG ‘Be CIPC Compliant’ website -

CIPC and alternative UK Sprout Suppressants

Due to its efficacy and modest cost, CIPC has been the sprout suppressant of choice on a global level for over fifty years. Regulatory pressures in the UK, and the stewardship response, has reduced the amount of CIPC available, which has resulted in a resurgence of interest in alternatives

Research carried out at AHDB’s Sutton Bridge Crop Storage Research has been looking into alternatives, which are at various stages of the regulatory process.

Adrian Briddon, Senior Scientist at Sutton Bridge, said: “For the fresh potato sector, I think we have become less dependent on CIPC over recent years and official government figures show some of the alternatives are being used. 

“For the processing sector though, this regulatory pressure is causing the most problems, because the scope of alternatives is more limited, and cost is more critical. Maleic hydrazide, applied in the field is being used more generally across the industry, which is helped by the benefit of volunteer control.

“However, ethylene and spearmint oil have only really achieved success in the fresh potato sector so far. While alternative sprout suppressants may not be considered as effective, their use in combination with CIPC may be more effective than just the sum of the parts i.e. synergy. Results of Glyn Harper’s work on CIPC with ethylene threw up some interesting outcomes and is now of particular interest.

How we use Sprout suppressants  

Most of the new alternative sprout suppressants are volatile, oily liquids and one is a gas. These compounds each require a different store management approach and a specific understanding of the application conditions required.

Because of a loss of apical dominance, treatments can have a modifying effect on stem numbers and some are being used successfully in seed management. In addition, some of the essential oils are also reported to control some pathogens.

Because they form vapour in store, many of the new sprout suppressants need longer store closure periods after application, to ensure complete ‘uptake’ of products. In many cases 24 hours is likely to be a minimum label requirement, so for processing stores, different types of equipment are likely to be used. The new products tend to be more dynamic compounds, being gases and vapours.

This may mean applications need to be more frequent, but buildings can subsequently be used for storage of other commodities and seed potatoes. This is not the case with CIPC, where a risk of cross-contamination persists for many years.

Further reading​



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