Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)

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David Bracey

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #15 on: March 19, 2012, 10:20:15 PM »
There are several mis-conceptions.

Glyphosate is translocated in the phloem which is why the chemical is effective on perennial weeds; it is tranlocated to the growing tips.  In my experience however it is never truly 100% and a follow-up treatment is generaly necessary.

The herbicidal activity of glyphosate was first reported by Monsanto in 1971. There are several manufacturers of this molecule to-day and it is widely available mainly under the brand "glyphosate". There is no "best" product however some formulations have a higher concentration than others,(ie 120gm to 360g/litre) so read the label for the dosage. To complicate things further there are several salts of glyphosate available. Unfortunately the dose is often referred to as litres (of glyphosate)/hectare rather than as a percentage of dilution. I am trying to check the dilution and will post it tomorrow.

Glyphosate can be safely used around plants with bark.  Glyphosate will only kill plants with chorophyll; it acts via the chlorophyll.

I know of no scientific evidence that the continuous use of glyphosate damages soil structure however there are rumblings in some quarters. It probably revolves around how you classify soil structure. It is true that resistant species have appeared over time including rye grass, Lolium species.

I happily use a knapsak sprayer using standard pressure and a small needle point jet .  This allows you to accurately hit the target without damage to adjacent plants.
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 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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JTh

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #16 on: March 19, 2012, 11:30:12 PM »
Glyphosate is supposedly one of the least toxic pesticides around, but there seems to be increasing evidence that it may lead to hormonal disturbances at least in snails and aquatic organisms, and maybe also in humans?
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

ezeiza

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #17 on: March 19, 2012, 11:53:47 PM »
In my country, Argentina, and due to the widespread cultivation of transgenic crops, immense quantities of glyphosate are used. Yes, it provokes miscarriage in mammals (most kinds of farm animals) as the wind carries the chemical sprayed by planes. No evidence of soil damage so far but it has been found inside the grains. Small wonder the Chinese and other customers feed the transgenic soybean to animals.

David Bracey

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #18 on: March 20, 2012, 09:28:55 AM »
As promised yesterday............ I use a generic glyphosate containing 360gm/litre.  The recommended use for "easy to control annuals"
is : 50ml in 5 litres of water ie 1%.  The recommended dose for perennials is 70ml in 5 litres of water ie1.4%.  If you use a stronger or weaker product than you need to use proportionally more  less.

I have read Ezeiza`s comments and while it is true that "immense" quantities of glyphosate are used I have serious doubts that there are miscarriages due to its use.  This is an old chestnut.  The agrochemical world is very small and serious problems like this are soon identified and remedial action taken. There are many checks and balances at government and industry levels. 

JTh mentions hormonal damage; what hormone and what damage?  Its too easy to make statements like this without quoting the reference and being serious in a Forum which maintains a very high level of knowledge.

Glyphostae is toxic to most aquatic species and should not be used therefore around ponds, lakes, rivers and run-off areas.
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 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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Alisdair

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #19 on: March 20, 2012, 09:56:00 AM »
David, I don't think you are entirely right to say that glyphosate in itself is toxic to aquatic species, though if other chemicals are added to it - as perhaps they may be in non-Monsanto formulations - these other chemicals may themselves be toxic.
Glyphosate is approved for use around ponds and watercourses in the UK (and I believe in the USA) on the grounds that any toxicity is negligible. One glyphosate formulation - Roundup Pro Biactive - is specifically designed for such use; the glyphosate it contains is the same as in the normal products, but the adjuvants are slightly different.
The reason that glyphosate does not harm non-plant aquatic creatures is that - like all land-based creatures - their bodies do not contain the plant enzymes which glyphosate works by blocking.
Alisdair Aird
Gardens in SE England (Sussex); also coastal Southern Greece, and (in a very small way) South West France; MGS member (and former president); vice chairman RHS Lily Group, past chairman Cyclamen Society

David Bracey

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #20 on: March 20, 2012, 10:04:20 AM »
There is an excellent paper entitled "Glyphosate Resistant (GR) Weeds" by Nandula, Reddy et al from the University of Mississippi.

They review the GR problem around the world and identify 7 weed species "naturally resistant" to glyphosate including C. arvensis, Commelina, C. album and A theohrasti.  From my experience I would also include Portulaca oleracea.

"Evolved resistance" due to continuous glyphosate use lists Ambrosia, Conyza species, Eleusine, Lolium , Plantago, Amaranthus tuberculatus.  In general these are not serious weeds of mediterranean areas.

The authors go on to say that if continuous glyphosate use is mainatined there is a good possibility that the usefulness of glyphosate will be diminished.  They go on that the answer is Herbicide Rotation, which of course is good agricultural practice.
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

David Bracey

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #21 on: March 20, 2012, 10:13:12 AM »
Alisdair you may well be correct that the adjuvants are more toxic to aquatic species that glyphosate.  However  if I read the literature and the French label it definitely states not to use glyphosate around water. 

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 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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Alisdair

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #22 on: March 20, 2012, 11:03:37 AM »
I don't know about David's French glyphosate formulations, but anyone wanting to use Roundup safely on or around water will find these detailed instructions helpful.
Alisdair Aird
Gardens in SE England (Sussex); also coastal Southern Greece, and (in a very small way) South West France; MGS member (and former president); vice chairman RHS Lily Group, past chairman Cyclamen Society

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JTh

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #23 on: March 20, 2012, 12:58:19 PM »
I should have been more specific and said that there are some indications that glyphosate  may cause disruption in hormone signalling, here are a few references:

‘Rana pipiens tadpoles chronically exposed to environmentally relevant concentrations of POEA or glyphosate formulations containing POEA showed decreased snout-vent length at metamorphosis and increased time to metamorphosis, tail damage, and gonadal abnormalities. These effects may be caused, in some part, by disruption of hormone signaling, because thyroid hormone receptor beta mRNA transcript levels were elevated by exposure to formulations containing glyphosate and POEA. Taken together, the data suggest that surfactant composition must be considered in the evaluation of toxicity of glyphosate-based herbicides. (see Toxicity of glyphosate-based pesticides to four North American frog species. Howe CM, Berrill M, Pauli BD, Helbing CC, Werry K, Veldhoen N.  http://www.ncbi.nlm.nih.gov/pubmed/15352482)

There is an interview during a meeting in Denmark with Prof. Gilles-Eric Seralini, where he says that ‘My team has noticed that Roundup disrupts hormones (chemical messengers) which are modulating the oestrogen synthesis. Oestrogens are known as female hormones, but today we know that they are important for bone growth and testicular function at very low doses. So a modulation of oestrogen synthesis could account for sperm decline, increase in cancers and sexual malformations. So we have to be careful with the hormonal effects of GM crops and the associated herbicides.’ see http://www.ecochem.com/ENN_glyphosate(2).html

Walsh, L.P. 2000. Roundup inhibits steroidogenesis by disrupting steroidogenic acute regulatory (StAR) protein expression. Environ. Health Persp. 108:769-776. is another  study on effects on hormones. These scientists at Texas Tech University studied the effect of a glyphosate containing herbicide on hormone production. They looked at hormone production by Leydig cells, located in the testes, which play a crucial role in male reproductive function. The scientists showed that exposure to a Roundup herbicide reduced sex hormone production in these cells by 94 percent.

R. Hokanson et al. in their study: Alteration of estrogen-regulated gene expression in human cells induced by the agricultural and horticultural herbicide glyphosate (Human and Experimental Ecology (2007) 26,747—752 wrote: ‘Gene expression is altered in mammalian cells (MCF-7 cells), by exposure to a variety of chemicals that mimic steroid hormones or interact with endocrine receptors or their co-factors. Among those populations chronically exposed to these endocrine disruptive chemicals are persons, and their families, who are employed in agriculture or horticulture, or who use agricultural/horticultural chemicals. Among the chemicals most commonly used, both commercially and in the home, is the herbicide glyphosate. Although glyphosate is commonly considered to be relatively non-toxic, we utilized in vitro DNA microarray analysis of this chemical to evaluate its capacity to alter the expression of a variety of genes in human cells.’

It is probably not glyphosate alone, but the cocktail of this and other factors that may constiute a threat, among them modified insecticidal Bt toxins that are produced by GM plants which have developed resistance to glyphosate, ref. Mesnage R, Clair E, Gress S, Then C, Székács A, Séralini GE. Cytotoxicity on human cells of Cry1Ab and Cry1Ac Bt insecticidal toxins alone or with a glyphosate-based herbicide. J Appl Toxicol. 2012 Feb 15. doi: 10.1002/jat.2712. From the abstract:
‘ In these results, we argue that modified Bt toxins are not inert on nontarget human cells, and that they can present combined side-effects with other residues of pesticides specific to GM plants.’

In a study by Céline Gasniera, et al: Glyphosate-based herbicides are toxic and endocrine disruptors in human cell lines. Toxicology Volume 262, Issue 3, 21 August 2009, Pages 184–191, http://www.sciencedirect.com/science/article/pii/S0300483X09003047) they say that it is probably not glyphosate that is the most toxic component in various Roundup formulations, but  that other ingredients in the formulations  disrupt hormone function more efficiently than purified glyphosate. The findings show that the formulations act against the hormones to produce anti-estrogenic and anti-androgenic effects. There is a synopsis of this article here: http://www.environmentalhealthnews.org/ehs/newscience/roundup-mix-more-toxic-to-liver-cells-than-glyphosate/
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

pamela

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #24 on: March 20, 2012, 02:30:16 PM »
Thank you Alisdair, Anita, Ezeiza, Jorun and David, I now have a much clearer picture of this. Everyone has been most helpful.
Jávea, Costa Blanca, Spain
Min temp 5c max temp 38c  Rainfall 550 mm 

"Who passes by sees the leaves;
 Who asks, sees the roots."
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Hilary

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #25 on: March 15, 2020, 09:47:59 AM »
Oxalis pes-caprae, Bermuda Buttercup

Looking through THE MEDITERRANEAN GARDEN number 84, April 2016
 I came across an article by Fleur Pavlidis.
 Oxalis pes-caprae: AN INVASIVE SPECIES

This is a very detailed article, about how she copes with this invasive plant in her garden, which I think would be very informative for you who have gardens

Since I don't expect to have a postage stamp depicting this flower, I thought I would go out for a walk looking for the Bermuda Buttercup at the base of trees in the pavement, against walls and in the, mostly untended, beds near the sea. It was a very hot day, for the season, mid-March and in some places the leaves were turning yellow

In the evening I discovered that I did have a stamp and had used it in.this very  Forum.
http://www.mgsforum.org/smf/index.php?action=search2

There is a long discussion about the problem of invasive Oxalis pes-caprae which is where I am going to post this
Since all the places I snapped the Bermuda Buttercup were untended, the feeling that they were invasive and to be destroyed immediately was  missing and they made a cheerful sight.
MGS member
Living in Korinthos, Greece.
No garden but two balconies, one facing south and the other north.
Most of my plants are succulents which need little care

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Charithea

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #26 on: March 16, 2020, 05:06:06 PM »
Oh Hilary. The hours I spent removing these Pests.
I garden in Cyprus, in a flat old farming field, alt. approx. 30 m asl.

Hilary

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #27 on: March 16, 2020, 05:25:18 PM »
Yes, but you must admit that under some circumstances they look pretty
MGS member
Living in Korinthos, Greece.
No garden but two balconies, one facing south and the other north.
Most of my plants are succulents which need little care

Caroline

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #28 on: March 16, 2020, 11:06:02 PM »
Couldn't possibly concede that! Extermination the only answer...
I am establishing a garden on Waiheke Island, 35 minutes out of Auckland. The site is windy, the clay soil dries out quickly in summer and is like plasticine in winter, but it is still very rewarding. Water is an issue, as we depend on tanks. I'm looking forward to sharing ideas. Caroline

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Alisdair

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Re: Controlling Oxalis pes-caprae (bermuda clover, bermuda buttercup)
« Reply #29 on: March 18, 2020, 09:20:26 AM »
Hear hear!!!
Alisdair Aird
Gardens in SE England (Sussex); also coastal Southern Greece, and (in a very small way) South West France; MGS member (and former president); vice chairman RHS Lily Group, past chairman Cyclamen Society