A shorter dormancy in potatoes means sprouting is likely to occur earlier than normal, with experts urging growers to fog stores with the sprout suppressant chlorpropham as early as possible this autumn.

The warmer, brighter conditions during the growing season will have resulted in a short dormancy period, warns Adrian Briddon, Potato Council technologist and member of the Potato Industry CIPC Stewardship Group (PICSG).

Early fogging is also crucial in avoiding CIPC (chlorpropham) residues in potatoes, as highlighted by a new stewardship initiative this autumn (see panel).

“This strategy [going early] improves product efficacy and, where applicable, extends the interval period between applications,” he says.

There are no prescriptive time periods for CIPC applications, however Mr Briddon stresses that it is important to see CIPC as a preventative rather than a curative measure to comply with stewardship objectives.

“As soon as the crop is dried and cured, CIPC should be applied,” he advises.

“It’s therefore important to plan ahead and contact fogging contractors before the crop is harvested, so they’re lined up well in advance.”

This autumn also sees changes to CIPC product labels with new advice. This includes applying it within three weeks of harvest, or at the earliest occasion thereafter, even in the absence of signs of breaking dormancy.

In cold stores, CIPC should only be used once, with applications carried out before temperatures fall below 7C, he says.

A further change is to require fans to recirculate store air for at least six hours before CIPC application, without cooling – positive ventilation is recommended in all store types during treatment.

‘Be CIPC compliant’ initiative

The industry initiative launched in July aims to prevent CIPC residues being found in fresh and processed potatoes above maximum limits, thus securing its future use.

In addition to the new on-label advice, completing a CIPC store checklist is now a requirement under Red Tractor rules, having previously being voluntary.

The PICSG has also secured a commitment from the supply chain, with both the potato processors association and fresh potato suppliers association committed to only source potatoes from CIPC-compliant stores.

The campaign website (www.cipccompliant.co.uk) has information including best-practice tips, research findings, CIPC store checklists and the latest news.

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