Mint oil has been used successfully in the pre-pack sector in the UK to control sprouting. Its use in warmer storage this season is generally new, according to a news article published by AHDB.
Recently, there have been a few reports of product build-up in its liquid form on crops in processing stores in Britain, leading to some localised issues. The key to the effectiveness of mint oil is to keep the active as a fog during application.
AHDB provides some tips to help potato growers and storage managers achieve this.
Spearmint oil has been used for a number of years already in the industry, in particular for the fresh-pack market. The take-up has been relatively more recent for the processing sector and this season, there have been reports of build-up of the active in its liquid form. In extreme cases, this has led to store breakdowns as result of prolonged high-speed fan use.
It starts with keeping the crop dry
Mint oil is applied to the crop as a hot fog. In the presence of residual moisture on the crop however, this mint hot fog can ‘coalesce’ or collect and convert to a liquid, which can lead to concentrated deposits in some areas of a store.
To ensure the removal of excess moisture in the crop, it is recommended to run fans without cooling for 24h prior to application. Make sure to work with your contractor to set up the store correctly.
Striking a balance
Reduced speed fans will enable effective redistribution of mint oil throughout the crop and will provide a good balance between moving enough air, and therefore fog, and risking any concentrated deposits of mint oil on the crop.
Refer to the BIOX-M product label for further details on use of fans and recommended fan speeds for effective product distribution.
The new generation of potato sprout suppressants are all much more volatile (i.e. remain in the gaseous phase) than CIPC. So it is important to ensure there is no unnecessary and uncontrolled air exchange in the store, especially for 2-3 days after application, as this will increase product loss and reduce efficacy. It will also hasten the need to re-apply.
As an immediate measure, take steps to ensure stores are sealed as much as is practicable to prevent this and consider store upgrades for next season if the risk is considered significant.
How AHDB can help
Watch back the AHDB storage webinar where Adrian Cunnington highlights the importance of keeping the crop dry ahead of product application. Link to 28:08 in the video. Have you been having any issues following sprout suppressant application? Call the Storage Advice Line on 0800 02 82 111 to discuss your situation.