Herbicide warning

Before purchasing mulches or manures for your garden, ensure that they don’t come from pastures treated with a broad-leaf weed killer.
A relatively new herbicide (weed killer) ingredient, aminopyralid kills broad-leaf plants by disrupting plant cell growth. It does not affect grasses, but can remain active in them, and manures from animals that eat sprayed grasses, until it is completely broken down by composting or soil microbes.
Some readers may remember that, 16 months ago, I drew attention to the devastation this herbicide caused in UK gardens, rendering garden beds unusable for almost two years, after contaminated pasture was used as mulch, or uncomposted manures were dug into garden beds. UK residents were advised not to eat any produce from affected garden beds.
Despite extensive problems in the UK, and the fact that aminopyralid is highly mobile in soil, our Australian Pesticides and Veterinary Medicine Authority (APVMA) has approved herbicides containing aminopyralid under the names; ‘Hotshot’, ‘Starane’, and ‘Grazon’.
The APVMA Manager – Public Affairs told me that the APVMA requires products that contain aminopyralid to include on the label the following instructions: The herbicide is not be used on land to be cultivated for crops for up to 24 months. The herbicide is not to be applied to crops or pastures, which are intended to be cut for the production of compost, mulches or mushroom substrate to be used for susceptible crops or plants, as straw, hay or other plant material treated with this herbicide may damage the plants. Manure from animals grazing treated areas or feeding on treated hay is not to be used for growing broadleaf crops, ornamentals or orchards as injury to susceptible plants may occur.
However, these warnings do not help the many gardeners who are unlikely to ever see the herbicide label and, completely unaware of any potential problem, may inadvertently purchase contaminated products.
To test manures and mulch for herbicide residue, see: Manure and mulch warning update
If you are unfortunate enough to have beds affected by this herbicide, click here for treatment information.

11 thoughts on “Herbicide warning

  1. Can I apply hot hot with a wiper to prevent soil contamination. Does hot shot kill the seed if applied to flowering plants? Cheers

    No, Stewart, if you water the garden, or it rains, it will contaminate the soil, and it remains active for a long time. If you read the article you would know how persistent and damaging these products are to unintended targets. I do not recommend their use.

  2. Hi all, The dow site has a link to the hotshot material data safety sheet, which can be useful whe the label on the container is lost or faded.
    The warnings and plantback periods are clearly stated
    If you want to determing if your soil is still affected by residual, they suggest that you try and grow sample of a known number of seeds of a control crop and check for numbers of successful germination and crop health.
    See the section on soil bioassay Cheers

    Thanks, Mark. I did provide the information on how to test manure and mulch for herbicide residue in my post, Manure and mulch warning update. But some readers may not have seen it.

  3. Great blog, does Hotshot affect cats does anyone know as my cat got really sick after landlord sprayed
    Hi Terry, is your cat ok? In the case of suspected animal poisoning, you should immediately contact your vet. Pesticides and herbicides contain a cocktail of ingredients and your vet will be able to assess from Hotshot’s Material Safety Data Sheet (MSDS) if any are toxic to your pet.
    (Hotshot also contains napthalene and kerosene). Many of these chemicals can be absorbed through the skin (paws) and cats lick their fur to groom themselves.
    Information about the contents of various pesticides and herbicides can be found on the Australian Pesticide and Veterinary Medicine Authority (APVMA) website. Hotshot has APVMA Approval Number: 59173 – Lyn

  4. Hi Lyn
    Our neighbouring property has just been bought by a wealthy investor.
    He has just sprayed $50,000 of Grazon, a product containing aminopyralids, on his blackberries (by helicopter of course). I know this because it was talked up all over town!!
    Thankfully there is a high ridge along our boundary so the spray did not contaminate our land but I am horrified to think of all that toxic poison flowing down the gullies and rivers once it has attacked the blackberry.
    The stupid thing is the blackberry will recover and grow again but the uninformed farmers down the river will suffer ongoing toxicity.
    Thanks for your article. I will post a blog on this topic on my own site.
    Do you mind if I refer to your post?
    Thanks very much

    Catherine Hickson

  5. Aminopyralid is a big problem in the UK and an increasing problem in Australia and the US.

    Read George Monbiot’s recent blog and article in the Guardian this week. He’s gathering information about affected people so that something can be done about the chemical.

    Read this in the Guardian

    And this about the first case in the UK that is actually being seriously considered by the officialdom.

  6. I am so upset about this. I have a tiny yard, and 3 compost bins. Does anyone know how fast this stuff breaks down in a compost bin?
    If your problem is caused by affected manure, empty each bin in turn, replacing the contents – and dampen it with water, if necessary. Also add a sprinkling of lime or dolomite every 20 cm while refilling the bins. Then every week or two, turn over and mix the contents (checking that it is consistently damp) until the mixture has cooled down. Repeated mixing of the compost to aerate it will speed up the breakdown of the organic matter. The compost materials also reduce in size as they decompose. Don’t forget to add more lime if it has a sharp or sour smell.
    Depending on your climate zone, compost that is regularly turned can mature in 6-8 weeks in warmer areas and 3 months in cool areas. – Lyn

  7. Again excellent advice. But in general its nice to see a good blog on organic gardening especially for people new like me to growing there own organic veggies.

  8. This is excellent advice. Especially for those of us who are into gardening. Blogging is great, I am relatively new to it but I really like doing it. I probably like blogging because I like gardening. Lol.

  9. Hi Lyn, The problem is even if you ask the people selling the mulch 9 times out of 10 they can’t give you the info you want as they don’t know where their products come from,…..better start growing my own mulch then!!!

    I would be reluctant to buy these products from suppliers to do not know where they come from, and are not prepared to find out, Gabriella. These are suppliers who are only interested in a fast buck, and don’t care what sort of problems you have. Tell the supplier that it is too big a risk to take to have your garden unusable for a long period.
    If customer reluctance begins to affect their sales, they will soon start doing their homework, and ensure that they are providing a safe product. – Lyn

  10. gee this is a real worry. I buy lucerne and straw from our local produce store.. how on earth could i find out if herbacides are used?
    *sigh* and here I was thinking I am organic producing my own vegies..

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