Contaminated manure                                                                  June 2008
Farmyard manure tainted with a powerful pesticide residue is causing abnormal growth of vegetable crops, leading to a surge of complaints from allotment holders and gardeners.

The suspect manure originates from farms using the hormone-based herbicide aminopyralid, which is found in products marketed by Dow AgroSciences Ltd and is normally sprayed on pasture land to control weeds.

Manure from animals fed on these treated pastures is believed to contain enough chemical residue  to damage susceptible crops including potatoes, beans, peas, carrots and salad vegetables. Ornamental plants such as delphinium, phlox and roses may also be at risk.

Symptoms of damage include distorted foliage, with cupping of leaves and fern-like growth. The shoot tips grow pale, narrow and distorted, with prominent veining on the foliage. Growth generally is very stunted, leaving most crops unusable.
There are no remedies once damage has occurred and no assurance that affected produce will be safe to consume. However, there is no suggestion that children, pets, gardeners or wildlife are at risk.

There is currently no testing kit or way for growers to diagnose whether their manure is tainted. The Pesticides Safety Directorate are advising anyone who suspects their crops have been affected by contaminated manure to contact the supplier and try to confirm whether an aminopyralid product was used on any grass, hay or silage fed to the animals which produced the manure. It may be necessary to trace the original source if the grass, hay or silage was obtained from elsewhere.

If aminopyralid or one of the following products - Banish, Forefront, Halcyon, Pharaoh, Pro-Banish, or Runway - was used, then the affected grower should contact Dow AgroSciences for further advice at

This e-mail address is being protected from spam bots, you need JavaScript enabled to view it. This will help the company and the Pesticides Safety Directorate gather information on this issue.

The Royal Horticultural Society (RHS), which has received a number of calls about the problem, has issued further advice to growers regarding what to do with stacked manure and buying manure in the future.

RHS has advised that any potential residues in stacked manure can remain for extended periods, even up to two years. The best advice is to return the unused manure to the supplier for them to spread on grassland. If this is not possible, it should be spread on grassy areas. Well-rotted crumbly manure can be lightly spread on lawns in late winter. As a last resort, tainted manure can be consigned to the council refuse.

When buying manure in the future, growers should seek assurances from the supplier that the manure has not come from animals fed on grass or straw bedding treated with hormone weedkillers, especially aminopyralid products.
The Federation of City Farms and Community Gardens is monitoring this situation and will update its members as appropriate.
Federation of City Farms and Community Gardens.
Reg. Charity No. 294494
Registered in England No: 2011023
Registered Office: The GreenHouse, Hereford Street, Bristol BS3 4N