Potato haulms showing typical symptoms of aminopyralid poisoning. Growth is stunted and the edges of the leaves curl upwards in a strange spoon-like pattern. Photo © Green Lane Allotments.
If you're not yet acquainted with the news that gardens and allotments across Britain are being contaminated with a toxic herbicide residue, you can read the full story in today's Observer. There's also a very detailed article (with more pictures of contaminated plants) from some of the growers affected at Green Lane Allotments, who kindly provided the photo.
The gist of it is this. Gardeners have been finding their plants growing a distorted mess of curled up leaves with an almost fernlike appearance. The leaves curl upward tightly in a spoon shape, and the plants are stunted and don't grow properly. The curled leaves get worse near the top of the plant. It's known to affect tomatoes, potatoes, peas, beans, carrots and salad vegetables, but possibly not courgettes. Fruits and tubers either don't form at all or are distorted and sometimes rotten. The symptoms are those of hormone weedkiller poisoning, and it's showing up in organic gardens.
The poisoning has been traced to manure, which most of us use abundantly on our gardens. Specifically to manure evacuated from the backsides of animals fed on hay or silage made from grass which had been sprayed with aminopyralid, a hormone herbicide made by Dow AgroScience.
Thus the buck stops with Dow AgroScience, but I think we can expect them to squirm every which way to avoid being held accountable. They'll most certainly try to blame it on the farmers. There is a reason it's called AggroScience.
Aminopyralid is used on grassland to kill off meadow weeds. It's a new product, introduced in the UK in 2006 and is not licensed for use on food crops. Treated grass is fed to livestock, and the toxin stays in the grass matter as it passes through the animals' system and lingers in the manure even after lengthy periods of stacking. Then the following season gardeners spread it on their plots. As the manure breaks down in the soil the aminopyralid is released and poisons the crops. Nobody (not even Dow) knows whether the poisoned crops are safe to eat or not, because the stuff has never been tested on food crops.
I certainly add my voice to those calling for an immediate withdrawal of aminopyralid products and for some chain of accountability.
If you think you've got aminopyralid poisoning in your garden, I suggest you get in touch with one of the campaign groups like the one at Green Lane Allotments or refer to their blogs for the latest advice on how to deal with it. The RHS also has an information page about it. There may be some chance of making Dow face up to their responsibilities if confronted with enough evidence from enough people.
If you don't yet have a problem, I suggest being extremely careful about sourcing manure, including bagged compost products that may contain it ... or avoid manure altogether for the moment. If you buy hay to feed to animals whose manure you then spread on the garden, be very cautious even if your hay comes from a trusted supplier. The problem has been reported across the whole of the British Isles but I'm not sure what the situation is in other countries. It's also important not to panic if you see poor growth or distorted leaves in your vegetable plants ... the symptoms of aminopyralid poisoning are very specific. If your plants don't look like the photo above, you haven't got it.