Scotts and Vitax, the manufacturers of lawn herbicide products containing clopyralid, have been asked to tighten up labelling to make sure that gardeners do not see their crops damaged by green compost containing grass cuttings contaminated with the herbicide.
The companies have been provided with wording that must appear on all amateur products that contain clopyralid.
It reads: "After treatment, leave the clippings from the first mowing on the lawn. The next three mowings should be composted well, for at least nine months, before being used as a mulch. Do not dispose of the grass clippings via council composting schemes."
The update summarises the outcome of considerations of clopyralid following a review by the Waste & Resources Action Programme into the risk of damage from aminopyralid and clopyralid residues, which it said was low. The Chemicals Regulation Directorate (CRD) has said new wording will be obligatory from 15 February 2014.
A Scotts representative said: "The CRD has advised us that we will need to revise our existing wording on our labels to their phrasing. This is to ensure that all labels throughout the industry are the same. We have until 15 February 2014 to comply, so obviously it will not be an issue for us to do this."
Vitax technical manager David Senior added: "We welcome any clarification and standardisation of label advice to ensure the safe and responsible use of amateur products with clopyralid.
"All new production will be labelled in accordance with the latest requirements to ensure all products comply by February 2014."
But Pesticides Action Network policy officer Nick Mole said: "There is plenty of evidence that people won't read the small print. Whether the information will make any difference, I don't know."
A Health & Safety Executive representative said: "There is no human health aspect to this regulatory action." She added that "all those using pesticides are expected to read the product's label and to follow the use instructions including any post-treatment measures".
Managing the risk of chemicals on crops
Three years ago, aminopyralid hit the headlines after it was found to be damaging allotment crops fertilised using horse manure from animals that had eaten grass treated with it.
The ingredient was later reintroduced under "a stringent stewardship programme devised to prevent inadvertent movement of manure from farms".
Aminopyralid is only applied to land grazed by cattle or sheep - not land where forage will be conserved.
The Waste & Resources Action Programme review concluded that the risk of damage from weedkillers in compost was low. But there have been discussions aimed at improving the clarity of product labels containing clopyralid.Products that need new labels:
- Scotts Evergreen Gun Lawn Weedkiller and Evergreen Lawn Weedkiller;
- Scotts Verdone Extra and Verdone Extra Ready to Use;
- Scotts Weedol Gun Lawn Weedkiller and Weedol Lawn Weedkiller;
- Vitax LawnClear2, LawnClear2 Feed & Weed, LawnClear2 Ready to Use.