The long term storage of potatoes utilising CIPC as a sprouting inhibitor is under threat in the UK. Dr Reuben Morris of Frontier Agriculture discusses why and the action being taken to maintain its availability.
The Potato Industry CIPC Stewardship Group came into existence 5 years ago in response to residues of CIPC in potatoes that were above the Maximum Residue Level (MRL). Since then The Stewardship Group has ensured the best practice guidance for the use of CIPC in potato stores based on Sutton Bridge Crop Storage Research (SBCSR) trials is fully and rapidly implemented. The CIPC Stewardship Group website presents this guidance and is essential reading for anyone using CIPC during management of stored of potatoes.
So what further is being done to reduce the future likelihood of CIPC residues above the MRL in stored potatoes?
In the UK the majority of CIPC is hot fogged into potato stores by professional contractors who are members of the Applicators Group of The National Association of Agricultural Contractors (NAAC). This situation has enabled rapid uptake of new SBCSR best guidance on the hot fogging of CIPC. However, contractors are rarely responsible for all aspects of potato store management and so these other aspects are now being targeted in a new Stewardship Group initiative.
The potato store checklist
Trials at SBCSR have clearly shown that potato store design and management are crucial in reducing the total dose of CIPC required to inhibit sprouting during long term storage. Consequently, this season a Store Checklist has been introduced jointly by Red Tractor Assured Food Standards and The Stewardship Group.
What aspects of store management does The Checklist look to improve?
1) Store location: Do not apply CIPC to stores when it is windy. Wind 'pulls' hot fogged CIPC out of stores, reducing the dose that is retained on the potatoes. Sheltered stores are less affected by wind.
2) Store integrity: Leaks reduce the dose of CIPC that is retained on the potatoes.
3) Empty air space in store: A large head space above the pile/stack reduces the dose of CIPC that is retained on the potatoes. Avoid treating part filled stores.
4) CIPC application port(s): Are they correctly placed for even distribution the hot fog throughout the fully loaded store? Do not place boxes directly in front of ports.
5) Uniform store environment: Allow enough time after switching refrigeration off for air re-circulation to clear temperature gradients and condensation before hot fogging CIPC. This may take more than 8 hours.
6) Bulk store suitability: Is the flow of the hot fogged CIPC through the potato pile uniform? If not can the flow be balanced? Can fans running at low frequency be used to re-circulate the fog until it clears?
7) Box store suitability: Is the flow of the hot fogged CIPC through the pallet slots even? Do not over-fill boxes as this restricts the flow of the fog. Is the CIPC hot fogged into a central plenum?
If the potato store has two red scores on The Checklist it cannot be hot fogged with CIPC.
Frontier's contracting service for hot fogging of CIPC is a member of the NAAC Applicators Group and is applying The Checklist before treating stores this season. Where required, Frontier agronomists also provide store management advice as part of this service.