The move lifts a voluntary suspension of approval for sales and use, which the company sought in July 2008 after sensitive crops on some allotments and gardens were affected by manure containing traces of the herbicide.
Farmers use the product to control pernicious and poisonous weeds such as ragwort, thistles and docks in pasture. In specific formulations it also has the potential to control invasive weeds, such as Japanese knotweed, in amenity areas and industrial sites, Dow AgroSciences said.
Since sales and use were suspended, farmers have campaigned for the product's return because of the high levels of longlasting weed control aminopyralid-based products offer. Those who have used the product since its launch in 2006 saw improved pasture and enjoyed increased output from their fields, compared to that offered by other products on sale to control weeds in grassland.
Dow AgroSciences said it would not seek to reintroduce aminopyralid before ways were found to minimise the risk of any repeat of the "unfortunate incidents" of the past two seasons.
The active ingredient will be reintroduced with new recommendations and "a stringent stewardship programme devised to prevent inadvertent movement of manure from farms". Key to this is the requirement that products containing aminopyralid are only applied to land that will be grazed by cattle or sheep, not land where forage will be conserved. This requirement aims to ensure manure generated from treated grassland remains on the pasture. Problems have arisen when conserved forage from treated pasture was fed to housed livestock and manure created in large quantities.
Supporting these new recommendations is an enhanced stewardship package that will require anyone supplying or advising on the use of aminopyralid to be retrained in the details of product use. Those applying or using products containing aminopyralid are required to confirm in writing that they have been instructed on product use and manure management issues. These records form part of a user-traceability system.
"The new stewardship requirements are stringent. We believe they will mitigate against manure leaving farms where aminopyralid has been used and so help to safeguard against sensitive crops being affected," said Andy Bailey, Dow AgroSciences' principal biologist for grassland herbicides.
"The changes to how aminopyralid products will be used and the associated stewardship plan should allay concerns among gardeners and allotment-holders over using manure. However, it remains good practice to know the provenance of any manure as other materials can contaminate manure."
NFU deputy president Meurig Raymond said: "We are pleased to see the suspension on the use of aminopyralid lifted. Many grassland farmers have found this a particularly valuable product in improving grassland and controlling pernicious weeds, such as ragwort and thistle.
"However, it is clear that those recommending and using the products have a duty to follow the stringent new label instructions. Not only is it a legal obligation, but important for the reputation of the industry."
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