A WARNING has been issued to potato store managers not to apply the sprouting suppressant, chlorpropham, on crops going in to store in 2020.

The Potato Industry CIPC Stewardship Group (PICSG) said the popular active, previously used on more than 90% of the 3.5m tonnes of potatoes stored in Britain, had withdrawal removed by the European Commission on January 8.

The maximum ‘use-up’ period of nine months was set by the EU, with member states able to set their own date within that timeframe. This means the last possible use-up date is October 8 – during the very early

stages of potato store loading in a typical season – and a date now officially confirmed as the use-up date in the UK.

Dr Mike Storey, chair of the PICSG, said that businesses who have not been monitoring technical messages will be at risk of crops not passing inspection:

“This will become an issue at the point at which the maximum residue level (MRL) of CIPC allowable on potatoes for human consumption – which is currently 10 parts per million (ppm), drops to a new temporary MRL (tMRL). We think this will happen before the 2020 harvest comes out of store.

“We don’t yet know the tMRL rate, although AHDB has been part of a Europe-wide effort to submit data from commercial stores to inform this. We know where we hope it will be and it is at a level that will be achievable if you’re using stores that have previously used CIPC, as long as cleaning guidelines are followed. But if you apply CIPC to crop this year, it will not pass an inspection,” he warned.

Some countries, including potato superpower Belgium, have taken this possibility out of the equation by bringing the use-up period forward to June.

Adrian Cunnington, head of crop storage research at AHDB, believed many growers are aware of the changes and will know that the 2019 harvest is the last that can be treated with CIPC.

He said: “Most growers are on top of this situation, but we are still receiving some worrying reports that there are producers who are not fully aware of the changes and consequences.

“Any grower who applies CIPC in autumn, 2020, is at high risk of being unable to sell that crop. Our message is quite simple when it comes to CIPC at 2020 store loading – if you fog them, you can’t flog them.”

Alternative products are available – see the AHDB website’s storage hub – and to help store managers prepare, AHDB is offering free one-to-one potato store visits via its new Storage Network.

The Storage Network is delivered by Sutton Bridge Crop Storage Research and a group of independent advisors trained by specialists. Alongside eight additional storage research projects, it is part of an £800,000 ring-fenced fund to help the industry deal with the withdrawal of CIPC.