Potato growers and store managers across Great Britain are being urged to submit chlorpropham residue results by August 31, as the industry gathers evidence needed to retain the use of storage buildings previously treated with the former sprout suppressant.

GB Potatoes and the CIPC Residues Monitoring Group said the latest surveillance data showed that residues continued to decline following the withdrawal of CIPC in 2020. Around one in seven stores tested still returned a detectable residue, compared with approximately one in four during the first year of monitoring.

The reported detections remained within Great Britain’s current temporary Maximum Residue Level of 0.35mg/kg. However, the findings indicate that historic CIPC contamination can persist in potato stores several years after the chemical was last applied.

“The trend is encouraging and the industry deserves credit for the progress made. But we cannot be complacent. With around one in seven stores still showing a positive result, there is clearly more work to do, and thorough cleaning between storage seasons remains the single most important action growers can take,” said Adrian Cunnington, chair of the CIPC Residues Monitoring Group.

CRMG is particularly seeking greater participation from businesses supplying Britain’s fresh potato market. According to the group, the processing sector has strongly supported the programme, while stores serving the fresh sector remain underrepresented in the available data.

Results submitted by August 31 will be collated for submission to the Health and Safety Executive’s Chemical Regulation Division by mid-September. The evidence is intended to demonstrate continued compliance and support the retention of a temporary residue limit for potatoes held in stores with a history of CIPC use.

Growers and store managers are also being advised to clean storage buildings thoroughly between seasons, with particular attention to areas where residues can accumulate in the fabric of the store and associated equipment.