During late 2007 and 2008, many gardeners, allotment holders and commercial growers reported abnormal growth of their crops. This damage has now been attributed to the presence of the herbicide aminopyralid in manure used as a fertiliser and growing medium. There is, quite simply, “muck” in the muck.
Aminopyralid is a commercial herbicide that kills treated plants by altering their hormonal growth, and it is manufactured by the company DowAgro. It is the active ingredient in a number of different preparations:
* Banish
* Forefront
* Halcyon
* Pharoah
* Runway
* Synero
* Upfront
All of these are commercial preparations that were available only to professional growers and farmers, except Banish, which was marketed as a herbicide for use on domestic lawns. (I say ‘were’ because in July 2008 DowAgro suspended sale of aminopyralid products.)
Aminopyralid is a selective hormone-based herbicide for the treatment of broadleaf plants. In plain English, it is a weedkiller that kills broad-leafed weeds such as dock and ragwort, but leaves the surrounding crop (usually grassland in the UK) unharmed. It does this by binding to the target plant and imitating hormones called ‘auxins’. This results in rapid and uncontrolled cell division within the plant. This is called ‘epinasty’, and it results in the death of the plant.
The problem with aminopyralid is that, because it binds itself to organic matter, it persists for a long time; for as long as there is some organic matter it can bind itself to, it will remain present. It persists for so long, in fact, that DowAgro advises that ’susceptible crops’ (including a great many grown by the average gardener or allotment holder) should not be grown on treated land for at least two calendar years after spraying. Some scientists believe that aminopyralid can remain on treated grass for at least eighteen months after spraying, not necessarily killing the grass (remember, aminopyralid is ’selective’ so won’t affect some plants), but there nevertheless.
“a weedkiller sprayed more than one year ago, that has passed through an animal’s gut, was kicked around on a stable door, stored in a muck heap on a field, then on an allotment site and was finally dug into or mulched on to beds last winter is killing sensitive crops and will continue to do so for the next year . . .” - Shirley Murray, Quoted in The Observer, June 29th 2008
Organic matter that has been treated with aminopyralid does not necessarily stay on treated land. It may be eaten by ruminants such as cattle, either in the field or as silage, in which case the aminopyralid will pass through the animal and into its manure. It may be turned into hay and used to feed or bed a horse, in which case it will, again, pass through the animal and into its manure. On amenity land, treated grass may be cut, and the cuttings composted. In each case, the aminopyralid will persist as long as the organic matter does, and so the treated material is likely to end up miles away and on someone’s growing beds. If contaminated compost or manure is brought into your garden or allotment, the aminopyralid will be brought in with it, and could cause epinasty and death of your own plants. It doesn’t necessarily have to be your vegetables. It could just as easily be your prize dahlias. Click here for a list of the most commonly affected plants.
DowAgro are aware that the aminopyralid in its products does not break down in manure, and that affected manure therefore poses a serious risk to crops grown in it. DowAgro apparently believes that this is not their responsibility or their problem. DowAgro consider themselves entirely blameless; after all;
“Any DowAgroSciences product with potential to cause such an effect (e.g. those containing a substance known as aminopyralid) carry warnings on the product label and specific directions as to appropriate conditions of use.” - DowAgro Notice to Allotment Holders, June 2008
According to Dow, it’s your own fault if your crops are damaged and your land poisoned; you should have asked the manure supplier about a chemical you never knew existed. DEFRA take a similar line - Phil Woolas, the Minister for the Environment, states that “The difficulty lies not in the use of the herbicide products as such, but in the subsequent use of the manure”.
This defense is simply not good enough. Aminopyralid is being widely misused, and it is innocent people who pay the price of this. At the moment, aminopyralid has affected an unlucky minority. In the future, it could change the agricultural landscape and the live of every one of us. We will pay for the industry’s mistakes and for DowAgro’s greed.