Re: round-up pro

Monsanto's patent on glyphosate expired  in 2000, and since then there has
been a lot of competition, with marketing focusing on "faster-acting" and
"stronger" products.  I had always understood that using too high a
concentration would defeat its effectiveness, but manufacturers are now
adding surfactants to speed up the result.  Dr Hannah Mathers at Ohio State
University has been researching this subject for the past few years.  Here
is an excerpt from one of her papers:





Roundup Carryover Injury in Woody Plants: Roundup (glyphosate) has been
labeled foruse in ornamental plantings for over 30 years. It has been
utilized in the nursery and landscape industries extensively due to the
numerous attributes that it possesses. Some of these attributes are: limited
soil activity, non-volatile, broad-spectrum, systemic, low environmental
impact, ability to translocate throughout the plant, ease of use, and low
mammalian toxicity.  Roundup went off of patent in 2000, thus opening the
market to many generic brands of glyphosate.  In 2007, there are 41
different glyphosate products,such as Touchdown, Jury, Cornerstone, Roundup
Original Max, Roundup Pro, Roundup, Weathermax, and others. Each of these
glyphosate products utilizes various surfactants with varying doses.
Consumers tend to want a faster working product, thus the makers of
glyphosate products have incorporated many surfactants to break down the
cuticle of the plant. These products have been sold as providing better weed
control - which has not been shown in research and worse if contact is made
with nursery or landscape plants, injury may result.

Research is currently in place at Ohio State University to study different
glyphosate containing products with varying surfactants.

Glyphosate is readily broken down by microbes within the soil and is tightly
bound to clay, hence the limited soil activity. Although glyphosate is
broken down within the soil, once in the phloem of a plant, it may take
years to break down. This is considered a sublethal dose, thus causing
injury to the plant. Absorption of glyphosate is possible with thin barked
or bark with pigment (Kuhns 1992). Also, it is not yet known if glyphosate
accumulation is possible in mulch, thus contributing to glyphosate injury.
Roundup will have carry over if applied to peat (John Ahrens, personal
communications, 2007) so accumulation in mulch is possible. Injury symptoms
may not be present up to two years after absorption of glyphosate occurs
(Kuhns 1992).

There are several symptoms that will occur when a woody plant is exposed to
a sub-lethal dose of glyphosate. These include: witches broom, stunting,
bark cracking or splitting (Figures 1 and 2), loss of apical dominance,
individual dead limbs (Figure 2) (Mathers 2006), chlorosis, and/or death
(Kuhns 1992) (Ferrell et al. 2006). We speculate that the removal of suckers
and adventious shoots, especially with broad spectrum systemic postemergents
(especially new formulations of glyphosate) or shortly after mechanical
removal of suckers may be one reason for the increased severity and
frequency of bark splitting.



If you google "Hannah Mathers" and glyphosate, you will find several
articles.  Bottom line: although her research focuses on woody plants, there
is much still unknown about long term effects; I would keep my vegetables
away from it.




                                                              Josh
----- Original Message ----- From: "Theresa G." <macycat3@sbcglobal.net> 
To: <gardenchat@hort.net>
Sent: Thursday, May 22, 2008 9:24 PM
Subject: [CHAT] round-up pro



So- anybody know what the deal is with "Round-up Pro"?  How long does it
take to break down in the soil?  Is it safe to plant veggies in that area
after you used it- do all the chemicals biodegrade?? Thanks for any help-
Theresa

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