I am not perfect. I’m not even close. I’m not going to claim that, on every occasion, I immediately undo a wrong. But I try.
I’ve found that correcting wrongs as quickly as possible and as transparently as possible is much to be preferred over either denying that there was something wrong or trying to find some weasel-worded excuse to try and wriggle out of responsibility for the wrong.
I give that introduction because I’ve realised that I have been wrong about saying that Jacobaea vulgaris (syn. Senecio jacobaea), common ragwort, remains toxic when dead. The weasel-worded excuse would be to say that it should be obvious that the pyrrolizidine alkaloids (PAs) in the plant cannot last forever but the truth is that I had never thought through the decomposition process in full.
What has made me think about this is that I was sent a 2009 paper about measuring PA levels over time. The paper was written to look at a new testing method for measuring alkaloid levels in general but its conclusion is that there could be a better way to dispose of common ragwort when removed from pasture or land being used to grow animal forage.
To obtain aged samples of decaying ragwort, the authors sealed plants into black plastic sacks and left them in sunlight. The abstract says;
‘The experiments demonstrated a rapid decomposition of the toxins in ragwort stored in bags, from 340 mg/kg to less than 40 mg/kg in four weeks and virtually complete loss after 10 weeks.’
The authors conclude that further work might prove that this method of dealing with removed ragwort is preferable to incineration, currently the most common approach, though there would seem to be more effort involved in finding somewhere to hold the sacks of ragwort, away from cattle or horses, during decomposition and then having to remove the non-recyclable sacks before putting the detoxified plants into a composter.
It might be that detoxification would occur in silage removing these problems but a 1984 paper concluded that, though there was evidence of detoxification in silage, but not hay, the process was not reliable enough for ragwort contaminated silage to be used. That paper used Senecio alpinus not Jacobaea vulgaris so it is not even possible to say that common ragwort detoxifies to some extent in silage.
A further complication is that a 2004 paper found substantial differences in the type and concentration of PAs in different varieties of Senecio jacobaea.
What all this shows is that things are always more complex than we would like them to be.
I could try and excuse myself by saying that I try and make the main plant pages of this site useful for the general reader and, therefore, don’t include detailed complications for fear of deterring that reader. But, no excuse. I was wrong to say that dead ragwort was toxic without any further detail and I have now amended the plant page to give the more complex situation.
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