Potato growers and buyers have been warned against applying sprout suppressant chlorpropham (CIPC) at 2020 store loading.
The popular active, previously used on over 90% of the circa 3.5m tonnes of potatoes stored in Britain, has had withdrawal removed by the European Commission.
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 8 October – during the very early stages of potato store loading in a typical season.
This date has now been officially confirmed as the use-up date in the UK.
Dr Mike Storey, chair of the Potato Industry CIPC Stewardship Group (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,” he said.
“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,” Dr Storey added.
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, believes 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 their 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.”