[permaculture] Re: a herbicide for organic agriculture perhaps

Lawrence F. London, Jr. lfl at intrex.net
Sun Sep 22 16:15:17 EDT 2002


Subject: Re: a herbicide for organic agriculture perhaps
Date: Sun, 22 Sep 2002 13:32:40 +0800
From: David Menne <menne at IINET.NET.AU>
To: SANET-MG at LISTS.IFAS.UFL.EDU

Followed this up as the subject of trying to move towards safer herbicides
is always of interest to me. Even more interesting was that
"In fact, the knapweed leads a bizarre existence by producing two mirror
images of catechin. One form, known as negative catechin, is the
plant-killing poison, while its mirror twin, positive
catechin, kills off disease-causing bacteria in the soil."

Might need to be careful regarding first assessing any significant effects
on the Soil-Food-Web ?

In any event regarding the allelopathy :
1. Found that Centaurea maculosa is not poisonous : " it is consumed by
livestock [only when other vegetation is unavailable]. The plant releases a
toxin that reduces growth of forage species.
2. It is described [for us aliens unfamiliar with this weed - although I
notice in New South Wales it falls into the highest Weed Category, must
report & fully destroy] on :
http://www.ext.nodak.edu/extpubs/plantsci/weeds/w842w.htm

3. Agrimonia eupatoria L. (Agrimony, Sticklewort) might be a better source
of catechin
It has "Long used as a substitute for tea in Europe", and might be grown as
a value-adding byproduct of forestry as a high-value speciality crops are
cultivated under the protection of a forest canopy that has been modified
and managed to provide the appropriate conditions(*) - providing short-term
income while high-quality trees are being grown for wood products.

[This is suggested on http://www.agroforestry.co.uk/forfarm.html so
obviously the alleopathy does not harm the trees ? And replacing the full
sun noted as a requirement elsewhere is not critical ?]
(*)The amount of light in the stands is altered by thinning, pruning, or
adding trees to achieve 5-40% crown cover.
The estimable Jim Duke notes that Agrimony contains 2.6% catechin in the
whole plant [easier to harvest than roots] - also notes very useful
quantities of Ursolic Acid which is very much a medicinal cure-all; should
one start putting up extraction plants and equipment.

In any event, agricultually one might not extract the Catechin - instead,
lay "hay" on the ground for it to leach into the weed root zones ?


   AGRIMONOLIDE Plant: DUKE1992A

   ALPHA-AMYRIN Plant: DUKE1992A

   APIGENIN-GLUCOSIDE Plant: DUKE1992A

   CATECHIN Plant 26,000 ppm; DUKE1992A

   CATECHIN-TANNIN Leaf: DUKE1992A

   CERYL-ALCOHOL Plant: DUKE1992A

   COUMARINS Plant: DUKE1992A

   ELLAGIN-TANNIN Leaf: DUKE1992A

   FAT Seed 350,000 ppm; DUKE1992A

   GALLO-TANNIN Root: DUKE1992A

   LUTEOLIN-GLUCOSIDE Plant: DUKE1992A

   PALMITIC-ACID Plant: DUKE1992A

   QUERCETIN-GLUCOSIDE Plant: DUKE1992A

   QUERCITRIN Leaf: DUKE1992A

   SILICIC-ACID Exocarp 120,000 ppm; DUKE1992A

   STEARIC-ACID Plant: DUKE1992A

   TANNIN Leaf 50,000 - 80,000 ppm DUKE1992A

   THIAMIN Leaf 2.4 ppm; DUKE1992A

   TRITERPENES Plant 15,000 ppm; DUKE1992A

   URSOLIC-ACID Plant 6,000 ppm; DUKE1992A
David Menne : http://www.plantsfood.com

"We can't solve problems by using the same kind of thinking we used when we
created them" - Albert Einstein (1879-1955)





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