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Potato stocks up 23 per cent during first season for lower CIPC rates

1 March 2018

Growers urged to ensure continuing use of ‘active recirculation’ in stores in line with new label requirements

Dr Mike Storey, AHDB’s Head of Resource Management and Chair of the Industry CIPC Stewardship Group, said: “We have been working with the industry for some years now overseeing a ‘step down’ process as part of  CIPC Stewardship. The companies that hold approvals have reduced rates, which helps ensure compliance with the Maximum Residue Level (MRL) of 10 mg/kg.”

For the 2017-18 storage 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. These must not be exceeded. 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, compliance with 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:

 

High stock levels

The introduction of the lower rate has coincided with the highest level of potatoes stored for six years. AHDB Potatoes recently released their November stocks figure at 3.6m tonnes. This followed a growing season that saw five per cent increase in planted area to 122,779ha coupled with one of the highest average yields on record (49.3t/ha).

Growers have commented that this, and a wet harvest, has caused problems in stores but these do not appear to be in connection with the new CIPC rates.

Russell Price of Russell Price Farm Services Ltd. said: “There were some issues with rots developing in stores early in the storage season and we had to move some crop early. We have a plan to meet contracts and moving away from this can create a concern for growers in terms of store management, cash flow and our customer’s ability to take material early, which thankfully they were able to accommodate.

“Things seem to have settled down now and the crop is storing well. The CIPC seems to be working at the new rates and we’ve had no issues with early sprouting. It looks as if the crop will hold.”

No fan, no fog​

Dr Storey said that a shortage of storage space created issues for some growers: “The high stock levels did mean that some growers were looking to use stores that had not been modified to meet new label requirements. CIPC contractors did not treat these and crop had to be moved. “

Critically, fans are required, with CIPC needing to be actively recirculated at low speed during the application process, and until the fog has cleared. This applies to all applications throughout the season.  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 is normally 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 http://www.cipccompliant.co.uk/uploads/fileman/cipcapplicationguide.pdf

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 (0.01mg/kg).

More information is available in the Store Assessment of the Red Tractor Combinable Crops protocol at http://assurance.redtractor.org.uk/contentfiles/Farmers-5611.pdf

Growers having storage issues can contact AHDB Potatoes storage advice line free on 0800 02 82 111.

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