Potato Review

www.potatoreview.com POTATO REVIEW JANUARY/FEBRUARY 2021 41 STORAGE authorisation was not granted, as well as reviewing the impact that a livestock feeding ban would have on the sector. Knowing that CIPC would not be available for the 2020/21 storage season, the campaign kicked-o in earnest in January 2020, with a forum held at Fera’s premises in York attended by Defra and CRD sta , jointly hosted by the PPA and the Fresh Potato Suppliers Association (FPSA), and attended by growers such as Tim Rooke. reats to the industry were highlighted to the audience in a number of presentations, with the aim of building their understanding of the situation. is was followed up with visits to a number of stores varying from modern, well- sealed ones with good ventilation to older, less e cient ones. AHDB Crop protection senior scientist: Pesticide Regulation, Joe Martin, said: “We ensured that requests for more information, such as additional information on the stewardship programme, and mechanisms for limiting the number of potatoes treated with 1.4DMN were answered as quickly as possible. We were also asked questions regarding Red Tractor Assured Food Standards.” Some of the questions were at very short notice, but, given the urgency of the situation, all di erent stakeholders pulled together to ensure CRD had the relevant information to present to its Expert Committee on Pesticides (ECP), he added. Andrew said the original scenarios identi ed that around 750,000 tonnes of potatoes across mid and late storage would ideally need to be treated with1,4- DMN. However, the nature of Emergency Authorisations (which the regulation states should be for “limited and controlled use”) meant that such a high volume would not receive approval. Such authorisations are usually to address acute problems for minor crops, rather than a large and important sector such as potatoes. Andrew said: “As we moved forward with the application, the regulator deemed that the use of 1,4-DMN on even 10% of the UK crop production was still not considered to be limited enough. “As a result we had to work with AHDB to evaluate, based upon the available evidence from their trials and other sources, which were the varieties with the worst problems amongst those destined for late storage presented the greatest risk, and as result the nal submission was for approval for use on a much more limited 196,000 tonnes.” COLLABORATION BETWEEN SUPPLY CHAIN MEMBERS Collaborating with other growers and supply chain representatives in the request for emergency approval for DMN is Tim Rooke, Vice Chairman of the NFU potato forum who grows potatoes for crisping and also supplies McCain Foods. Tim grows around 240 ha of potatoes, two thirds of which are for crisping while the others are for chipping, he is reliant on long term storage often reaching into May or June so his customers have a steady and reliable supply throughout the year. He, alongside other growers and members of the supply chain, had written to their MPs, about the problems the sector is facing since the withdrawal of CIPC, and in January 2020 attended the meeting with the regulators at York. “It was a collaborative event that included everyone from agronomists and crop advisers to the processors,” he said. “We also took them out and showed them around stores and explained why approval is so important for the sector and to help them understand the impacts of losing a chemical for which there is no direct replacement.” Although ethylene and mint oil have approval for use as sprout suppressants, and they work for potatoes in cold stores destined for the fresh-pack sector, where the tubers are more dormant, they are not e ective on processing potatoes. is is a huge headache for growers like Tim. “Chipping and crisping potatoes have to be held at ambient temperatures of 8-9deg.C to maintain fry colours. As a result, the tubers are not as dormant as they are at cooler temperatures,” he said. “ e approved alternative sprout suppressants are poorly suited to processing storage. Ethylene can cause the sugars to spike at the warmer temperatures. ese sugar spikes result in a darker fry colour which is unacceptable to the processors.” Blanching the potatoes to whiten the colour after a sugar spike may be a solution for French fry processing but it is not an option for crisping manufacture because it changes the texture. e other approved alternative, spearmint oil, despite having clearance for processing potatoes, had performed poorly in research done in stores at the higher range of temperatures such as 8-10deg.C over long term storage. He emphasises the di cult situation that the sector is in, which will become even worse as the storage season goes on. “We followed the advice of AHDB and applied maleic hydrazide in the eld before harvesting. e chemical is perhaps better known for controlling volunteers, but can help prevent sprouting and research has shown it to be a successful pre-treatment for the other alternatives. “ is will take us through until early in the New Year, but after that we will be stepping into the unknown. at’s why the industry needs solutions such as the emergency approval of DMN.” ➜ Adrian Cunnington said AHDB estimates this EA has saved the industry £20m