Potato growers using metaldehyde slug pellets this spring are being reminded to follow stewardship guidelines and keep the active ingredient out of watercourses.
The reminder comes after water companies reported the worst autumn for the detection of metaldehyde in watercourses since 2017. Wet autumn weather made drinking water catchments particularly vulnerable.
Metaldehyde pellets are being phased out because of environmental concerns. Defra says alternative pesticides containing ferric phosphate provide effective control without the same risks to water and wildlife.
Water companies reported 168 cases of metaldehyde limits being exceeded in abstracted water last autumn. For one company, this meant shutting 14 abstraction facilities for 127 days when they should be filling reservoirs ready for the summer.
Affinity Water catchment manager Alister Leggatt, who represents Water UK, said: “This issue has had a knock-on impact on our ability to provide safe and affordable drinking water to our networks in a number of regions.”
David Cameron, chairman of the Metaldehyde Stewardship Group, said: “Stocks of the slug pellet cannot be sold after the end of February 2021 – but farmers may continue to use up existing stocks until 31 March 2022.
“We’re therefore urging responsible use of pellets right up until the end of the use-up period to help stop metaldehyde reaching watercourses in all areas of the UK – especially in drinking water catchments.”
Metaldehyde slug pellets should only by used as part of an Integrated Pest Management (IPM) programme. Growers should contact their local water companies for information about any available support.
Soil and stubble management, planting methods, slug trapping and monitoring should all be part of a good slug control programme. If pellets are needed, growers should abide by all stewardship guidelines.
Mr Cameron said it was important to minimise the risk of metaldehyde reaching watercourses. “It is critical that this continues right up until the use up deadline date of 31 March 2022 to safeguard water quality.”