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Metaldehyde: Advice for autumn crops

Metaldehyde is a slug pellet that can contaminate watercourses, especially when it rains. Here's how to avoid that happening.

The Environment Agency is calling on growers to think ‘slope, soil and stream’ when they apply metaldehyde based slug pellets to crops this autumn.

It is important growers adhere to the current guidelines on metaldehyde use to avoid contaminating watercourses and protect drinking water supplies.

Metaldehyde is the pesticide that most often causes risks to drinking water sources, especially in the autumn. Farmers need to operate ‘best practice’ to avoid pollution. If metaldehyde enters watercourses it can potentially threaten drinking water quality.

Good practice from farmers is required to prevent metaldehyde entering watercourses. This includes taking into consideration:

  • The slope of the field. Steeper fields are a higher risk.
  • The drainage status of the field. Heavy soils and under-draining are a high risk.
  • The proximity of watercourses or ditches. Fields adjacent to these are high risk.
  • The current and predicted weather. Saturated soils and heavy rain can cause a high risk of runoff.
  • The filling and wash down area of the pellet applicator. Areas which run off to drains or watercourses will have a high risk of pollution.

Visit www.wiyby.co.uk and enter the relevant postcode to find out if your land is in a high risk area (safeguard zone) for metaldehyde.

Metaldehyde Stewardship Group guidelines promote restrictions to prevent the pesticide from causing water pollution:

  • Use minimum active per ha to avoid drainage and run-off losses
  • Maximum application rate 210g metaldehyde active substance/ha* For additional protection of water, suppliers/BASIS advisors may recommend rates reduced to 160g active substance/ha or less*
  • Maximum total dose from 1 August to 31 December: 210g metaldehyde active substance/ha* For additional protection of water, suppliers/BASIS advisers may recommend rates reduced to 160g active substance/ha or less*
  • Maximum total dose rate: 700g metaldehyde active substance/ha/calendar year*
  • No pellets to be applied within six metres of a watercourse
  • Do not apply when heavy rain is forecast
  • If drains are flowing do not apply metaldehyde based slug pellets

*from any combination of metaldehyde products. 700g is also the statutory limit.

Alternatives, such as ferric phosphate, are available and you should consider using this or other modes of control if you are in an area where metaldehyde is identified as a risk to drinking water sources.

For further advice contact the Metaldehyde Stewardship Group on 0845 177 0117 or visit their website at www.getpelletwise.co.uk.

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