Potato processors have given the go-ahead for controlled use of an as yet non-UK-approved sprout suppressant.

Agriculture and Horticulture Development Board (AHDB) has secured an emergency authorisation (EA) for the use of 1 4 dimethylnaphthalene (known as DMN).

The approval is limited to the supply chains of some major processors, as the Chemical Regulations Division (CRD) of the Health and Safety Executive (HSE) turned down an original wider application made in August.

Approval has been granted for its controlled use on a limited number of varieties, pre-nominated by member companies of the Potato Processors Association (PPA).

These varieties will be used for crisp and French fry manufactures and a limited tonnage can only be used from long-term storage to supply the nominating companies.

DMN will only be applied to stored crops by contractor members of the National Association of Agricultural Contractors’ (NAAC) post-harvest treatment group.

To qualify for treatment, under the EA, other sprout control products must be known not to have worked or be able to work. Crops will be tested to ensure they meet eligibility criteria agreed with CRD as a condition of the approval.

Potatoes may only be supplied to factories where the waste will be segregated as part of a stewardship process. This is because it is also a condition of the EA that treated potatoes cannot be used to feed livestock.

Adrian Cunnington, head of crop storage research at AHDB, said: “Without access to DMN for the final three months of storage, the crisping sector would’ve had to resort to bringing crops in from overseas to fulfil the storage-gap.

“We estimate this would have cost around £20m and left British growers without a market for their crops. Gaining this EA has been a long and complex process, especially when you include our original application made in the summer that would have covered over 500,000 tonnes of potatoes – but we are glad to have got it over the line in the nick of time.

“AHDB applies for 70% of the emergency approvals in the potato and horticulture sectors, and has robust research programmes to show that other products do not work in certain situations.”

An application for full UK approval of 1,4 Sight, the product containing DMN, has been submitted to CRD by manufacturer DormFresh and is currently under consideration.

This will allow it to become more widely available once fully approved. It is currently authorised for use in eight European countries.