Vermiposting and juglone

actionclawJuly 7, 2010

I've researched this a bit and havent found anything useful, done a little experimentation but not sufficient to yield anything conclusive so I'm wondering if any of you may have experience or information about this.

Juglone, a nasty substance produced by black walnut trees is toxic to many plants. (For those that aren't familiar but interested, do a search to find plenty of info.)

I try to gather all the falling leaves, nuts, etc and keep them away from the garden, composting areas, etc but it's not always possible to keep the leaves 100% segregated. Some say composting black walnut leaves is safe, others disagree. I'm not so sure so don't chance it. On the other hand, I understand that vermiposting has been found to be quite a purifier, able to eliminate all sorts of harmful substances, I believe, even viruses, diseases, etc.

I don't know if it's, first, the nut worms and isopods followed by the wigglers or if they all join in from the beginning but somebody loves the walnut materials: nuts, husk, leaves etc leaving big piles of "black gold" that I hesitate to use.

However, to further complicate matters, apparently juglone is also an effective dewormer.

" ..while the hulls are extracted and used in alternative medicine. The black walnut tree contains the chemical compound juglone, a known toxin that has well-documented herbicidal properties. Juglone is toxic to many species of animals and plant and is found in particularly high levels in the leaves, roots, husks and bark of the black walnut tree.

..."Veterinary Herbal Medicine" cite several 19th-century sources that claim black walnut to be effective in killing and expelling intestinal worms from animals..

So, my question(s) become: Can vermiposting eliminate juglone or negate the effects of juglone?

Are Walnut trees/juglone safe to (composting as opposed to parasitic/intestinal) worms?

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Although it has a long and illustrious enough history that I think it's clear that black walnut has at least some anti-parasitic properties, AFAIK, no one has ever determined WHICH kinds of worms and parasites that black walnut is effective against. Roundworms (Ascaris sp.)? Hookworms (Ancylostoma, Necator spp?) Tapeworms (Cestoda sp)? Earthworms are not even closely related to these parasitic worms.

Since we don't know how black walnut works or why, there's no way to say if it could harm the worms. Personally, I suspect it does not.

Is it in the compost? This site says probably not:
"Walnut leaves can be composted because the toxin breaks down when exposed to air, water and bacteria. The toxic effect can be degraded in two to four weeks. In soil, breakdown may take up to two months. Black walnut leaves may be composted separately, and the finished compost tested for toxicity by planting tomato seedlings in it. Sawdust mulch, fresh sawdust or chips from street tree prunings from black walnut are not suggested for plants sensitive to juglone, such as blueberry or other plants that are sensitive to juglone. However, composting of bark for a minimum of six months provides a safe mulch even for plants sensitive to juglone. "

Here is a link that might be useful: Black Walnut Toxicity

    Bookmark   July 8, 2010 at 5:23PM
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I'm aware of that, in fact, I believe I've seen that exact article. Unfortunately, I've also read others that say different. When composting there are so many variables: trying to keep things sorted, keep track of which pile is which, different rates of decomposition (of a stray nut,for example, compared to leaves), etc. etc.

I did find toxicity testing by planting tomato seedlings a good idea and have done it several times. However, even with that, if it doesn't go well, is juglone necessarily the culprit opposed to fungus or some other issue? Not every tomato seedling survives. So for better results one should use several seedlings for each test but how many tomato plants does one want to sacrifice?

Anyway, I'm familiar with the whole "safe vs unsafe to compost Walnut tree parts" issue and, as I said, at this point I'll just continue to segregate as much as possible and not risk it. Often that separate bunch of Walnut tree material seems to be largely consumed by worms leaving what looks like some high quality poop BUT I know it's from those dang Walnuts! (Yes, I have done some testing with that, as well, but haven't come to any conclusions I trust completely.)

Because composting worms are known to be such great purifiers, I'm just wondering if there's any definitive evidence whether or not they are able to filter out the harmful effects of juglone.

    Bookmark   July 14, 2010 at 3:16PM
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If you are seeking definitive proof, I suggest you do a search of the scientific literature available at your local university's library if they have a Phytopathology or Soil Ecology program.

It would be a great topic for a doctoral dissertation.

    Bookmark   July 14, 2010 at 6:46PM
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