On Apr 25, 1:35*pm, "Pat" wrote:
"Elmo" wrote in message

...



On Sun, 25 Apr 2010 17:06:15 +0000 (UTC), Elmo wrote:

Mostly, I'm left with huge tangles of poison-oak stems ... so I ask ....
WHERE does weed killer get INTO the plant and how?

This journal article implies only the leaves can uptake the glyphosate ....
both the underside and the upper side ... but HOW do they do that?
http://www.jstor.org/pss/4043711

What is the mechanism of uptake?

Bear in mind, leaves act like a child drinks from a straw ... i.e., water
transpires OUT causing a vacuum which brings water and nutrients in from
the ROOTS ... but glyphosate isn't applied to the roots ... it's applied
to
the leaves.

It's all very confusing ... if the leaves are transpiring OUTWARD, why
would they suck in the wet glyphosate? What's the mechanism to suck INWARD
water from the leaf?

There are better brush killers than roundup. *Brush killers are absorbed
thru the leaves. *They also can be applied to a fresh cut stump in a
concentrated form. *I would be using Garlon instead of roundup. *I would
apply it to the leaves a few days before I cut the plant down. *When I cut
the plant down I might also paint some on the stump. *I would then reapply
it to any regrowth from the roots every few weeks. *The best time to use a
brush killer is when the plant is actively growing in the spring. *I might
also buy a couple of goats to help with the regrowth.

Herbicides that are absorbed through the leaves can be rendered
ineffective if mixed to strongly. This is because of their systemic
nature. It takes time for the active ingredient to make it to the
roots. If excessive ingredients are present it just kills the leaves
and leaves the roots. Unfortunately the public demand was to have
instant results so lines of herbicides were placed on the market that
killed leaves and little else.

Jimmie