Aminopyralid – Killer cow muck; Killer compost.
Charlie Heasman; 7th June 2019
Skerries allotments, May 2019
Tomato plant showing classic symptoms
When I first started writing this blog I thought I’d be talking about growing healthy veg, working with nature and all things joyous. Now, for the second time in three months, I’m writing about something nasty.
You may recall that in April the subject was the huge amount of waste we allotment holders collectively produce, the illegal dumping of it, and the problems and expense of dealing with the consequences of same. I’ve a feeling that we have not seen the end of all this and that another rant may not be too far ahead in the future.
But that’s another day’s work; here and now I want to alert everyone to the dangers of herbicide contamination which can, and is, finding its way in to our allotments wreaking absolute havoc as it does so.
The problem is aminopyralid poisoning, and it’s on the increase. None of us can afford to ignore it or pretend it doesn’t exist. It does, and it’s only going to get worse.
The problem, at least in our plot, first appeared last Spring and initially we had no idea what was wrong. Our tomatoes were the first to show signs, with the growing tips curling into tight gnarled knots, the stems growing long and spindly so that they couldn’t support their own weight, and further growth ceasing altogether. Symptoms, in short, identical to those in the photos above. Not ours, incidentally; those are this year’s plants and someone else is the lucky owner.
At first we thought it must be some sort of virus, though what and where it had come from we had no idea.
Then other things started happening. Perfectly healthy broad beans – raised in modules in the polytunnel – were planted out, sat in the ground for a week or two, tried to flower when only six inches tall, and died. A row of peas was perfectly healthy and growing well for most of its length, but at one end seedlings died faster than we could replace them. All other veg seemed pretty much okay.
If this was a virus it was acting in a very strange manner indeed.
At the same time our friend Carmel, who has two plots in two different parts of the allotments was having identical problems not only with her tomatoes but also with her potatoes: all showing exactly the same leaf curl symptoms. This was a little surprising because our potatoes were perfectly fine.
The penny finally dropped: we had both used the same batch of cow manure.
One further piece of evidence was an absolute clincher as far as we were concerned. I had spread manure on most (but not all) of the allotment and nearly all of the polytunnel. In fact I ran out three quarters of the way up the second bed of the tunnel and applied compost instead. The tomatoes planted here were perfectly healthy, showing no signs of stress and stayed that way for the summer. All the rest we had to take out and replace with fresh plants, this time grown in grow bags.
Ditto the peas, which had also received compost except, as you might by now have guessed, one end which did get manure. Entirely by accident, and nothing to do with judgement, our potatoes didn’t get manure either. And stayed healthy.
We now needed absolutely no more convincing that the cow muck was in some way to blame. But how?
At this point I did what I invariably do when I’m stumped: I Googled it. The answer came up time and time again: aminopyralid. Try it yourself, there’s an ever increasing amount of information out there – most of it, significantly, from organic growers and gardeners.
In fact all of a sudden everyone seems to be waking up to and talking about the dangers. Here in Ireland Klaus Laitenberger from Green Vegetable Seeds talks about it in his June newsletter and over in Somerset organic grower and gardening guru Charles Dowding posted a Youtube video two weeks ago.
For my part, I was going to say nothing just yet because I recently started doing a trial and wanted to see the full results before saying anything. But fresh outbreaks are occurring almost weekly in Skerries allotments and it would be pretty useless to wait and warn people after the event. In any case, I have some results already and am about to share them here.
I kicked myself last year for not retaining a sample of the suspect manure for laboratory testing, which I thought would have settled the matter one way or another. (Some people were still insisting that the cause was a virus; others blamed late frost, nitrogen excess and anything else they could think of).
In fact lab testing is not an option here, mostly because it is prohibitively expensive. There probably isn’t a facility in Ireland anyway; samples would have to be sent to England or beyond. The problem is that aminopyralid can cause damage even when present in minute quantities, 1 part per billion will destroy sensitive crops such as tomatoes, potatoes and legumes, and 1 part per billion takes a lot of finding in even the most advanced laboratory.
So I had nothing to send for testing and wouldn’t have been able to afford to do so in any case.
Then, at the beginning of last month, I heard that someone elsewhere in the allotments had spread cowmuck over almost his entire plot and planted potatoes, with disastrous results. I don’t know the guy, I’ve never met him, but I can quite confidently tell him that he has aminopyralite contamination. I might never meet him anyway because I’m told that at this point he walked out, shut the gate, and vowed never to return. Shame.
But at least he’d left the remnants of his manure pile behind, so I helped myself to a bucketful. Back in our allotment I took soil from a bed that I knew to be clean and filled flowerpots with a 4:1 mix of earth and cowmuck. Soil was taken from the same spot, mixed 4:1 with compost and also potted up, the pots were labelled. Pea plants and two tomato plants went into each sample, were given the same subsequent treatment and kept side by side to see what transpired.
21st May, peas and tomatoes potted up.
Peas two weeks later (compost on left, cowmuck on right)
And the tomatoes
To my mind the evidence is irrefutable, but as a backup I subsequently planted a couple more tomatoes, french beans and four potatoes. These are not ready yet but I’m confidently predicting the outcome.
This might prove there’s something wrong with the cowmuck, but of course it doesn’t prove what exactly. For this we must revert to the internet, as said earlier. Google aminopyralid images and see what you get; you’ll get pictures like these. Search for written texts or videos and you’ll get the same story.
So what is this aminopyralite, and what’s the story?
It is a herbicide manufactured by Dow Chemicals and is licensed here for the control of broadleaved weeds in agricultural grassland and has been around for the last decade or so. On this side of the Atlantic it is most commonly sold under the name of Forefront; in America as Grazeon. In 2014, after much controversy, it was withdrawn from the market here (at least in the UK; I’m not altogether sure about Ireland) and that should have been the end of it. But in 2015 it was reintroduced with exactly the same formula and the only difference being enhanced safety guidelines on the packaging. One of those guidelines was that users should ensure that treated grass or hay should not be allowed to enter the compost chain.
Clearly this is not working.
Aminopyralid is absorbed by all the vegetation it is sprayed on. Broadleaf weeds die; grasses do not. But those grasses retain the chemical and one way or another (as grass, hay or silage) are eaten by cattle, sheep or horses, pass through them and end up in the manure.
It will eventually break down but no two authorities can agree on how long this will take. Estimates range from one year to five. I hope to prove here that one year is hopelessly optimistic. Back to Carmel.
Last year she carefully took all of the cowmuck that she could back out of her beds; a laborious process as one can imagine. Also, by the very nature of things, inexact. This year she rather foolishly planted her tomatoes in the same place – she won’t mind me saying so because she’s kicking herself anyway – and got the same results. Those are her tomatoes in the first two photos.
So that batch of manure at least has remained virulently active for two years so far despite Carmel’s best efforts to remove it.
Meanwhile another grower is experiencing the problem in his polytunnel this year for the first time. Again, reef everything out and replant in growbags. He is not best pleased either.
At this point I should stress, very clearly, that I am not blaming any individual for the problem in our allotments. I’ve been told the name of the farmer from whom the manure came, but I’ve never met him. Those who have tell me that he is a conscientious type who adopts best farming practices and would be appalled by all this, and I have no reason to disbelieve it.
Which leaves the question hanging in the air: where did the contamination come from?
I’m also told that he buys in some of the winter fodder for his cattle, and it is entirely possible he bought the problem in completely unwittingly on a contaminated delivery of hay. This is the crux of the problem: the stuff is so insidious, persistent and invisible that it is virtually impossible to avoid it. As if to prove the point, yet another allotment holder this year bought in horse manure, from an entirely different source, and is experiencing exactly the same problems.
So what can we do?
Apart from call for the stuff to be banned, which we should, the short and rather glib answer is to be very careful. Klaus makes an eloquent point in his blog when he calls gardeners “the canaries in the coalmine” (or was it Michael D Higgins who said it first?). It’s bitterly ironic that organic growers are the ones hardest hit by malpractice or carelessness in modern conventional farming. We are told that aminopyralite poses no risk to the human food chain but we can see that it can, and does, pass through livestock and poison future crops. It would seem reasonable to question whether it is therefore present in the meat or milk. We’re currently reassured that there’s nothing to worry about but we were told the same about thalidomide, DDT and a whole host of other things which were subsequently proven to be very bad indeed.
One thing we could do in the meantime is to stop using weedkillers ourselves. Most in the allotments don’t anyway; a disappointingly large minority still do. Perhaps if they come to realise that these sprays are not only bad for the environment but bad for themselves they will stop.
So, no sprays and no manure. What’s next? We have to get our fertilisers from somewhere, right? Buying ready made proprietary brands of compost should be safe.
It should, but it still might not be so.
Manufacturers will go to great lengths to ensure that their supply chain is not contaminated – it’s in their best interests to do so – but it can, and does occasionally, happen. Levingtons, a name to be trusted, fell foul in 2016 when customers complained of failing crops. In fairness to the company they admitted liability and ‘compensated’ the victims with replacement plants and suchlike; small comfort for anyone who’s just lost the best part of a season’s production.
This from one anguished lady:
Jan H says:
Levingtons are selling contaminated Grow Bags again this year. Ironically I bought 20 of their Grow Bags with vouchers that they gave me as part of my compensation for last years lost crop. I am now in the process of losing all my crops again except for those which I planted in my homemade compost which are all growing normally. I would urge anyone with twisted, distorted and deformed plants to shout about it. How do we get this stopped? We are being sold poisonous compost to grow our food in. Who in authority can put some weight to this and get it stopped? I am witnessing 5 months of work wasting away, all that labour and a lost crop again…….
Sustainable Skerries 
Charlie, you are to be congratulated on your extensive blog of Aminopyralid. Sadly, our allotment association/council does nothing to educate plot holders on the use of herbicides or weedkillers. One plot holder spend £££’s on a weed killer he buys online to spray mares-tail and is convinced it works, but it doesn’t.
Perhaps the only sure way to avoid contamination from AP is to make more compost from our own green waste. This can be difficult I agree to make the quantities required, however I have been able recently to have access to spent hops, this helps bulk out the the compost pile and seems to make an excellent product.
Newcomers to allotments need to be educated on the benefits of home composting could be a start and councils educated on the use of weed killers.
Thanks again for your report.
Thanks Ron, totally agree with your comment about making our own compost. That is exactly what the wife and I decided last year when we got our AP attack: no more buying in. We stepped up our compost production and now produce more than enough to fill our needs.
We are lucky in that relatively few people in our allotment compost so I intercept their green waste and it goes into my bins. Then mix with a little(!) woodchip to bring up the carbon ratio, and I can turn a batch round in 4 months if I try hard.
I’m also trying to spread the word on the benefits of composting, aware that I might be shooting myself in the foot because if everyone does it there’ll be no surplus for me. I’ll cross that bridge when I come to it!
And no, no amount of weedkiller kills mares-tail.
Closed loop systems are the answer here, so a proportion of your allotment or garden should be used to produce fertility. No system dependent upon external inputs is sustainable anyway, and sustainable we must be.
Agree completely Mark.
I had exactly the same problem about 10 maybe 15 years ago with clopylarid infection in large walled garden where I worked in Scotland. It took us ages to finally identify it and we traced it to the leaves we had allowed the council to dump with us to make leaf mould. Little did we know the council at that time was spraying the parks and ground under the trees with this chemical. Otherwise we were completely organic. I believe then it was sold in a lawn weed and feed product too but I had believed it had been banned so sad to hear it has re-emerges. Totally devastated the kerb side compost recycling project in California which had to be stopped. Only solution was to dump all of our leaf mould and work a completely closed system using only what we produced ourselves in the garden
Thanks Jan, I’m happy to report that to the best of my knowledge our local CC don’t use it, but I’ve emailed our Green Party councillor asking him to make enquiries.
In any case, it’s in their own best interests not to spray because otherwise they risk contaminating their own kerbside compost recycling.
This is almost identical to our experiences about 10 year’s ago see here http://ossettweather.com/glallotments.co.uk/acmanure.html in our case the problem was horse manure. The compost contamination tends to be chlopyralid which is an ingredient in lawn weedkillers. If disposed of incorrectly treated lawn clippings find their way into green waste which is then used in commercial compost. Report your experiences to the CRD and Dow.
Hi Sue,
I’ve just read the manure section on your website (which took me some time let me tell you!) and I have to say that it is no fault of yours that not everyone knows of the problem. Well done and keep it up.
I’m not sure how much of a problem AP has been in Ireland over the years; we were completely unaware of it until we got our contamination last year. When we did it was easy for us to Google the information because there was by then so much on the net from the UK.
I have to say that this year there are more cases in our allotments than ever before, so the problem most definitely is not going away.
Is it ok to share this with our local allotment FB group?
This has happened to me in Cheshire and I feel heart broken, angry and, at times, over-faced by the fall-out and how to deal with it. Luckily being ‘No-dig’ I’ve scraped off as much of the horse manure as possible (I know it won’t be enough) and, after a conversation with an equally concerned and shocked stable-owner, have been able to return it to his heap. I cleared all the edible crops as there is no way I would want to eat any of it and cut it up as usual layering into my compost heap with card etc BUT of course this was more wasted time as it puts the contaminants back into the cycle. Now I’ve got to find a way of disposing of a pallet compost bin full, and so it goes on. What a nightmare.
Hi Fiona,
share by all means, the whole idea is to make everyone aware. At least your stable owner was willing to take it back, but you’re still left with a whole knock-on pile of other problems. We share your pain; it happened to us. The fact that you’re No Dig helps as it was easier to scrape most of it off.
I think it might be a good idea for a copy of your results, to be sent to the Scottish Agricultural College (That’s what they called it when I was young and I don’t know if it still uses the same name).
My point is: you may be re-creating the wheel – or you may have discovered something of extreme importance.
One way, or the other, this surely requires much further investigation
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Thanks a mill for writing this post. It’s shocking but good to know.
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I cant believe this! Im using my own well rotted horse manure from piles that range from 4yrs old to 18months old and am having these issues with my crops.
I try to avoid sprayed forage for the horses, but farmers lie and tell you what they think you want to hear.
AP is obviously used by large and small forage producers alike as ive imported great quality haylage from the uk into ireland and also used irish forage. I thought these past years i’m a crap gardener as my crops dont seem to be doing well! Truly, i thought it was me! The only good cropping ive had are initial years before getting horses and using horse manure!
Potatoes always fail, so i gave up growing them – in fact i grow because i enjoy it knowing the yield will be minimal!…all this time due to AP.
Twisting leaves grace my beds year in year out – even yellowing of cucumbers that were doing well in compost, then planted into a soil and manure bed, start to twist, go yellow….i have the most odd shaped cucumbers growing, especially this year.
Im so disheartened tbh. For yrs of failure of crops and now i know why. Id rather it be my ineptitude than an insiduous poison in my soil and my manure as i spend thousands per yr in forage for 2 horses to get the best quality feed….and hours mucking out etc to produce the best rotted manure for my farm!! im so deflated as i *thought* my organic practices were organic!! Damn….makes me wanna give up farming altogether tbh, especially if those in industry know AP is highly toxic as compost and withdrew it, only to allow it to be used again.
Wow….i just realised a manure pile i have been using for a specific crop has been rotting for 7 years and that crops new leaf emergence produced twisted leaves, some folded up in half shut together.
So there’s proof that AP remains inert for years and is not affected by hot composting processes.
Try finding true organic feed for animals – the hay is loaded with dock and ragwort, catsear and numerous other Seriously toxic weeds for horses. Even buttercup is toxic to horses in haylage, but not in hay. So farmers feel forced to spray due to these very harmful weeds to livestock.
The old fashioned way was to go out in the fields and dig them up by hand. Try doing that with 100 acres! I dont blame the farmers, theyre not to know the consequences of these chemicals, until the have to rely on crops themselves and fail like i have for yrs!
Ive had ragwort and Catsear infect my land from hay with it in, the seeds germinating on my farm despite me trying to rot it down out the way. I spend a lot of time cutting and digging up noxious weeds ever since due to this, and i only have just under 10 acres.
Buttercup and ragwort toxin cant even be baled as the toxin leaches and infects the whole bale of forage. I almost lost one horse to wet buttercup toxicity in haylage.
Ive run out of answers/option….what are the solutions? Are there any ‘safe’ broadleaf compostable sprays that dont damage crops when manure is used?
Sorry to rant but after yrs of crop failures…and finding out about AP, how unpreventable it is to me to source forage free of it as a horse and crop owner….wits end has been reached!! Daaaammmnn!!
Hi Bee,
sorry for the late reply, I really must check the comments section more often!
Wow, you’re faced with a whole suite of problems and I’m not sure I can help much but first things first:
At least you now know you’re not a crap gardener! When we first got our contamination we didn’t know what was going on either and it was only because others were sharing information on the net that we were able to find out what it was. That’s why I wrote the post: the more information shared the better.
We immediately decided to go ‘closed loop’, no more buying in of manure or compost (I think I mentioned that even proprietary brands can be affected). This was easy for us to do because we are in a municipal allotment and many of our neighbours don’t bother composting at all; we simply stepped up production and diverted their green waste away from where they were dumping it and into our compost bins instead. Also, because we live in a seaside town we can collect as much seaweed as we like. ‘Brown’ material comes from woodchip delivered by local tree firms who are glad to get rid of it. You might not have any of these options, but if you can manage something similar at least your horticultural problems will be solved.
It took us just two years to get completely free of residual contamination and now we’re fine.
Allotment gardening is my area of expertise; horses are another matter. ‘One end kicks and the other end bites’ is nearly the extent of my knowledge. I gather that your horses are your primary focus so I apologise.
I understand from my reading that horses are more susceptible to AP poisoning than cattle or sheep and I know that ragwort is bad news for all three. I did not know that docks, catsear and buttercups in haylage are toxic to horses. No doubt the buttercup problem can be solved by avoiding haylage, but that still leaves the other three.
At least ragwort and docks have the advantage of being large and easy to see once a haybale is broken open so can be picked out (yes, it’s extra work!) So that leaves the catsear.
As any livestock farmer will tell you, a strong healthy sward will suppress weeds, so maybe it would be worth considering reseeding your pastures? More expense of course, but horses are notoriously bad grazers in respect of grassland management so I imagine it would be necessary periodically anyway. The one thing I know you’re not going to do is perpetuate the AP problem by using it yourself.
Thanks for your input, I’m about to repost it as another blogpost and good luck in the meantime.
Hi SK!
Thank you for your suggestions!
Before i discovered the AP issue contaminating my crops, i spent the spring re-seeding 2 acres to hopefully make my own hay. Evidently i somehow pre-cognitively knew i’d be needing to as i’m struggling to find ‘genuine’ organic hay locally as forage alternative.
I’m glad to at least, finally, after years of failed crops, know what the root cause of the problem has been!
I have many tonnes of contaminated manure piles so im considering turning them into ‘manure bricks’ and burning it!! That should destroy the aminopyralid herbicide at least!! LOL!
There’s many out there using local sourced manure from stables and suffering a terrible or slow growing crops – so i think the solution is to raise awareness as much as possible – which i have been on horse forums for those who like to grow veg too, and to alert them not to allow their manure to go to gardeners if they dont know how the crop is produced.
Charles Dowding on youtube has alerted many to the issue with videos…and i believe he has started a petition to get AP banned again – it was once banned but was allowed back on the market.
Dow chemicals have stated their labels state not to compost the product the herbicide AP is sprayed on, but users of the herbicide dont pass that info onto the end user of the product, unfortunately.
Upon further research, its not just aminopyralid based herbicides which contaminate manure and inhibit human food crop growth, there’s a few other chemicals that do the same, as Dow chemicals paid to have a few tested, and others turned out to be an issue too. If memory serves i think it was a research study done in kentucky, usa. I googled it.
You’re right about adopting a more ‘closed loop’ approach. I’m doing the same now and this year have started huge compost piles from organic material from the farm.
Fingers crossed the awareness grows and many of these damaging chemicals of the agri-industry get banned in the future, as contamination, as proven, is easily happening even under the most scrupulous measures…i.e commercial sold compost labelled ‘organic’ or even commercial sold bagged horse manure labelled ‘organic’ can easily have herbicide residues.
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I am so glad that I read your article. Recently I enquired about purchasing some manure and or compost for my raised beds. My garden is in Ireland and I am not sure if we have this problem here but all the same it is better to be safe than sorry. So far I have only used seaweed and I think that I will stick with that. Thank you for your well researched article.
Hi and thanks for your kind comments.
Yes, we do have this problem here in Ireland so please be careful (the post was about our allotment in North County Dublin).
We have since gone ‘closed loop’ and only use our own compost plus seaweed. I wrote that back in 2019 and since then there have been more outbreaks on our allotment complex.
Can I ask where you got the link to the post from btw? I’d be grateful if you could tell me.
Hi. I got the link on facebook on a group called Irish gardeners I’m sure. someone shared this link:
https://sustainableskerries.com/2019/06/07/aminopyralid-killer-cow-muck-killer-compost/?fbclid=IwAR2_KI2GLJp6FiH83COaaQcGkN_b5k1MkWREqmzfExG9IlB573geGByn1II
it sure if interesting information. Kind regards from Agnes
Hi, thanks for highlighting this. I’ve had this experience this year for the first time. I got my manure from a trusted friend. Is there anything we can do to stop it?
Hi Maire,
Once you’ve got the contaminated manure mixed in with your soil, it’s a waiting game for the soil microbes to digest the chemicals. Depending on which chemicals were used, depends on how long it’ll break down.
If you’ve used the manure as a top-dressing on your soil, you can diligently scrape it off, to lessen the damage to current and future plants.
Manure from cows and horses can be a mixture of chemicals as grassland is sprayed with persistent herbicides that can take 2yrs to be digested by soil microbes, and bedding like straw which commonly gets sprayed with glyphosate, can take a year to break down in the soil.
My manure piles have a mixture of chemicals (unbeknownst to me at the time of using the manure) and i am now in year 2 of crops in contaminated beds and the plants are suffering – mostly tomato and courgettes, beans, sweetcorn. Lettuce seems to be able to grow – i guess due to it being a simpler ‘life form’ of the plant kingdom, in comparison to fruiting plants.
Courgettes barely grow – slow growth, yellow leaves, still – in year 2. A 4 inch dressing was used and mixed into the soil.
I’ve discovered seeds from infected plants, if they germinate stay very small and barely develop.
I am hoping year 3 will be better. All i can say is its best to plant something in affected beds, as the plants themselves create more soil microbe life – so perhaps a green ‘crop’ of barley or other simple grasses, that you then till back into the soil. It keeps the soil active and more likely to break down the chemicals faster than leaving the beds bare, and hoping existing microbes do the job. We have to grow soil microbes to break down the chemicals…’sacrificial’ plants will encourage a broader soil microbe population.
Soil temperature, moisture and PH affect how well the soil microbes break down the chemicals. So keep soil fairly moist, warm, with a 6.5 ph – an environment microbes prefer – to aid them to break down the chemicals.
I am curious if mushroom spawn can break down these chemicals faster. Oyster mushrooms mycelium has been tested for being able to clean up water after oil spills. Mushrooms absorb toxicity so the fruiting bodies should not be eaten, but due to their capacity for digesting toxicity, i am curious if they would be useful to neutralise persistent agri-chemicals, im yet to personally test this.
Thank you very much for that very useful information.
This happened to us last year from manure – all our peppers, chilis and half our tomatoes gone. Same as you we couldn’t figure it out for ages, no signs of viruses or pests. Then my husband sent me a picture of pyralidded (that’s what we call it now haha) peppers and although we didn’t want to believe the horror stories, it was so obvious what we were dealing with.
This year (we live in the middle East so now is the time) we are digging out as much of the contaminated beds as possible and using them for brassicas and corn, and using home compost on the previously infected beds and crossing our fingers.
One thing to note, we saved Moonglow tomato seeds from last year. We started them last month and already they are showing the leaf curl 😦 they were also really slow to germinate. Other purchased seeds show no signs. So be aware of this if you are saving your heirloom seeds it may just be better to repurchase.
A worldwide problem for sure!