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

How does weed killer get INTO the plant (leaves? roots? stem? mechanism?)

Spray vegetation killers like Roundup contain glyphosate and a toxic
surfactant. The surfactant helps spread the glyphosate on the plants'
exterior for maximum effect.

That's confusing toxicity of the surfactant with effectiveness as the
herbicidal agent--it isn't effective at all as part of the herbicide;
it's purpose is simply to serve as a surfactant to counteract surface
tension of water and wet the foliage thereby promoting takeup.

....

... It's important not to saturate the ground when using a
spray vegetation killer around vegetation you don't want destroyed
because it can easily leech into the soil and also become a systemic
poison for wanted vegetation. ...

Glyphosate breaks down and/or attaches very quickly in the soil which
renders it ineffective. Also, since its action is only via enzyme
interaction at active growing points within the plant it is not,
therefore, effective as a pre-emergent herbicide.

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