Metaldehyde reduction results promising

Early indications suggest the metaldehyde stewardship campaign has helped reduce the amount of the slug pellet active ingredient entering watercourses.

But maximum levels have been exceeded in some instances showing that more needs to be done to promote responsible use of metaldehyde slug pellets.

The campaign promotes and encourages the responsible use of slug pellets to minimise the environmental impact of their use and, in particular prevent, the active ingredient entering watercourses.

Initial data show levels of metaldehyde detected in watercourses has significantly reduced, said Metaldehyde Stewardship Group spokesman Colin Myram.

“Levels increased slightly in November and then declined, but they are nowhere near as high as last year.”

But the results, which included data from water company tests and Voluntary Initiative catchment studies, only ran up to mid-December. “We are still waiting for results for the rest of December and January,” he said. “When these are available we need to meet the water companies and discus the results in more detail before we can determine the final picture.”

Guidelines for pellet use 

– 5m no-pellet buffer around all water courses and ditches

– Keep pellets out of field margins; switch off when turning; treat headland last

– Don’t pellet if heavy rain forecast or leaching and/or run-off likely

– 700g/ha max per year; 250g/ha max per application; adjust rate to pellet size

– Treat according to need, use trapping

It was too early to determine the exact reasons for the reduction but it was probably a combination of better stewardship and reduced pellet use, he said.

“Market research shows that farmer awareness of metaldehyde stewardship is very good, but it was also a very dry season and pellet use was down dramatically.” The introduction of pellets with lower metaldehyde concentrations would also have helped, he added.

But despite the reduction, maximum metaldehyde levels had been exceeded in some cases. “Data show that there were some peaks after rainfall when drains would have been flowing and there would be greater risk of run-off.”

Direct application of pellets into watercourses could also be to blame, he noted. “As yet we don’t have enough information to pinpoint the sources, but we will be looking into this in more detail.”

Despite the marked reduction in metaldehyde levels, the campaign needed to maintain its momentum. “We need to stop exceedances taking place which will involve coming up with new ideas for reducing levels as well as continued promotion of metaldehyde best practice,” said Mr Myram.

For more information on responsible metaldehyde use visit our slug pellet academy at

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