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Author Topic: Calling our chemists : opinions on DockStar / asulam  (Read 1485 times)

SallyintNorth

  • Joined Feb 2011
  • Cornwall
  • Rarely short of an opinion but I mean well
    • Trelay Cohousing Community
Calling our chemists : opinions on DockStar / asulam
« on: April 25, 2018, 04:16:24 pm »
I've discovered that the hay and haylage I've been using since midwinter is from grass treated with DockStar.

Reading about asulam (the active ingredient in DockStar) I have concluded that persistence through into muck doesn't look like being an issue, so am planning on using some of the pony poo in the compost for our vegetable and salad growing.

However, having read about asulam being banned by the EU for use on food crops, I am now a bit glum about having fed grass treated with it to livestock we are planning to eat :(

We aren't organic, but do try to be as chemical-free as we can - so this is a bit of a blow.  And I've fed a lot of this haylage to our dairy cow too - including a bit as a milking-time treat before we dried her off.  Should I not do that in her next (impending) lactation?  She loves it - but we like to think that her milk is a very pure product! 

Any of our chemists able to tell me a bit more about it? 
Don't listen to the money men - they know the price of everything and the value of nothing

Live in a cohousing community with small farm for our own use.  Dairy cows (rearing their own calves for beef), pigs, sheep for meat and fleece, ducks and hens for eggs, veg and fruit growing

Womble

  • Joined Mar 2009
  • Stirlingshire, Central Scotland
Re: Calling our chemists : opinions on DockStar / asulam
« Reply #1 on: April 25, 2018, 05:11:52 pm »
The active ingredient in Dow Doxstar Pro looks to be fluroxypyr (is that the same as asulam, Sally?), and there's a fair bit of information on it here.

The most relevant pieces of information I can see are:

Mammals - Acute oral LD50 (mg kg-1)   > 2000
Mammals - Short term dietary NOEL   (mg kg-1)   > 80
Soil degradation (days) (aerobic)   DT50 (typical)   13.1, Non-persistent
DT50 (lab at 20oC)   13.1, Non-persistent
DT50 (field)   51, Moderately persistent
Dissipation rate RL50 on and in plant matrix 5.5

What that means in practical terms is that it doesn't degrade all that quickly when applied to plants or soil (some of these substances degrade extremely quickly in daylight, which is a great thing - they do their job and then promptly disappear!). However, there is presumably a decent length of time between spraying the fields and haymaking, and again a good length of time between haymaking and Daisy munching it, so that will significantly reduce the concentration she is exposed to.

To (badly) interpret the toxicology data, If Daisy weighs 400kg, you'd have to force feed her 800g of the stuff as a still-active ingredient to give her a 50% chance of death. Also, looking at the "NOEL", which is the anticipated no-effect-level, you could feed her up to 32g of it on a short term basis and expect to see no effect on her health whatsoever. Practically, I don't see how you could feed her anywhere near that amount, even if you tried (you could even do a BOFP* calculation based on the field application rate and hay yield per hectare to put your mind at rest, if you felt so inclined).

So, if fields can be grazed a week after application, and that's been tested as safe for both animal and human health, it seems to me that the dose Daisy receives will be significantly smaller. The same goes for any lettuces grown in affected dung or horse muck.

Of course, it's hard to relate that directly to concentrations in milk, and subsequently any health effects on people who drink it. However, I'd cheerfully drink a pint of milk alongside my lettuce sandwich, and would not worry in the slightest.

Does that help?  It certainly passed ten minutes for me when I should have been doing something else less interesting!




*Back of Fag Packet  ;)


« Last Edit: April 25, 2018, 07:37:38 pm by Womble »
"All fungi are edible. Some fungi are only edible once." -Terry Pratchett

SallyintNorth

  • Joined Feb 2011
  • Cornwall
  • Rarely short of an opinion but I mean well
    • Trelay Cohousing Community
Re: Calling our chemists : opinions on DockStar / asulam
« Reply #2 on: April 25, 2018, 08:28:56 pm »
Well I just found my bookmark about Grazon / *pyralids, and I am much reassured, because there's absolutely nothing like this on the DockStar leaflet.  I didn't read the DockStar Pro one mind...

Aminopyralid, clopyralid, and picloram I think all pass through into manure, and are even present after composting.  Grazon contains clopyralid.

It does say on the label:
"Do not use any plant material treated with GRAZON 90 for composting or
mulching.
Do not use manure from animals fed on crops treated with GRAZON 90 for
composting."

:bookmark:  Thanks for the definitive list of persistent-through-hay-and-digestion weedkilkers, foobar :thumbsup:
Don't listen to the money men - they know the price of everything and the value of nothing

Live in a cohousing community with small farm for our own use.  Dairy cows (rearing their own calves for beef), pigs, sheep for meat and fleece, ducks and hens for eggs, veg and fruit growing

SallyintNorth

  • Joined Feb 2011
  • Cornwall
  • Rarely short of an opinion but I mean well
    • Trelay Cohousing Community
Re: Calling our chemists : opinions on DockStar / asulam
« Reply #3 on: April 25, 2018, 08:29:18 pm »
Thank you Womble  :-*
Don't listen to the money men - they know the price of everything and the value of nothing

Live in a cohousing community with small farm for our own use.  Dairy cows (rearing their own calves for beef), pigs, sheep for meat and fleece, ducks and hens for eggs, veg and fruit growing

 
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