Derris dust

Following my post on organophosphates and ADHD, one of my blog readers asked for more information about derris dust (rotenone) that has been popular with organic gardeners for pest control as rotenone is an organic pesticide made from the roots of a tropical plant. It also has a long history as a piscicide (fish killer).
Rotenone works by shutting down energy production in cells, which makes it a neurotoxin. Research linked it with Parkinson’s Disease, but this was largely discounted as the rats in the research had rotenone injected directly into their brains, which is not a very fair trial.
In 2007, the USEPA published a Re-registration Eligibility Decision (RED) assessing only the risks of contact from its use as a piscicide (i.e. swimming in or drinking treated water). The RED stated that small children and foetuses were more susceptible to the effects of rotenone.
According to Environmental Health News, researchers have found that rotenone selectively destroys dopamine-producing cells in petri dishes. (The full document on this research must be purchased).
In 2010, another study was published about research in mice that showed a progression of Parkinson’s-like symptoms after mice were fed low doses of rotenone over a period of time. The research found that concentrations in the central nervous system were below detectable limits, yet still induced Parkinson’s Disease pathology.

Australia’s APVMA has reviewed rotenone and decided that it can still be used as a pesticide. However, both Canada and the United States are phasing out the use of rotenone for everything except its use as a fish poison. In Canada, for example, rotenone could not be sold for livestock, gardening, or domestic pet use after the end of 2008, and existing stocks can’t be used after the end of 2012.

I certainly don’t recommend the use of Derris dust, but gardeners must make their own evaluations of this pesticide.

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7 Responses to Derris dust

  1. Chris says:

    Thanks for this useful post. It just goes to show that some organic based pesticides can be quite harmful indeed. I will be looking for other alternatives for my brassicas next season.
    Chris, avoiding pests on brassicas can sometimes be as simple as correcting the soil pH. Brassicas can only absorb both the trace elements they need for healthy growth and natural pest resistance if the soil they are growing in has a pH close to neutral. Too acid or too alkaline and the butterflies and moths lay their eggs underneath the leaves. – Lyn

  2. Amy says:

    Today I accidentally ate unwashed spinach covered by Derris dust. Later on I vomited and had a bad diarrhea. Since it has been very popular with local organic gardeners I never had a doubt but I don’t think I ever use it in future. I will stick to my homemade garlic/chilli spray from now on. I am still in shock that this happened today. I will swap my veggies bed soil with flower bed tomorrow. Now I am feeling not so comfortable buying my veggies even from the local certified organic producer. Thank you for posting this info.

  3. JennyH says:

    Who would be an Australian?? I won’t be waiting for our regulators to ban this product in gardens. I will ditch mine now. I tried some eucalyptus and lavender oil but it was too strong and the little plants have shriveled up. I will try diluting it a lot more and start working on soil pH.
    What pests were you using the eucalyptus and lavender oil on, Jenny? – Lyn

  4. Diane says:

    Hi, I bought some Rotenone to eradicate the mites/lice on my free range chooks.
    Is this really a dangerous dust? Could it affect their eggs?

    Hi Diane, I certainly don’t recommend using derris dust (rotenone). It is a neurotoxin. Can’t refer to any research regarding eggs, but foetuses and children are more susceptible to its effects.
    This article provides some information about it – Derris dust
    All we have ever done to treat and prevent lice and mites is sprinkle elemental sulphur (flowers of sulphur) and agricultural lime on their perches, in their nest boxes and around where the hens take dust baths. A pinch of sulphur per bird in feed on a regular basis also makes the birds resistant to lice, mites, fleas and ticks. – Lyn

  5. Diane says:

    Thank you so much for the advice. I will remove the Rotenone immediately…..the chickens hate it as much as I do 🙂

  6. norman boldt says:

    I’m looking for some rotenone or derris dust to kill off a pond with ruff fish .. can you help. I have a aquaculture Lic to raise Perch and Blurgills

    Sorry Norman, can’t help you. I’m an organic gardener and never use rotenone or derris dust. – Lyn

  7. Gerald Bradley says:

    I am urgently looking for an alternative to Derris Dust for treating gooseberry plants. I read above a mention of garlic/chilli spray but no details were given. I would really appreciate some details. Thank you, Gerald
    Sorry for the delay in replying, Gerald, but you haven’t said what is affecting your gooseberries, or where you live. Is it aphids, mites, grubs, or are you trying to grow them in an unsuitable climate zone (which makes them vulnerable to pest attack)? There is not one solution for all these problems.

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