Pre-treat weeds with soapy water before spraying weed killer?

J Burns wrote: Stormin Mormon wrote:
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Why do you have your line-length set to 50-odd characters instead of, say, 72?
Regarding roundup, the only place I use that is in my parkinglot at $dayjob and on the road in front of my house (in the cracks around the curbs) or on my driveway. There is no other place where spraying roundup in my yard wouldn't kill either grass or something that my SO would kill me for.
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I buy Roundup in premixed 5-liter hand-pump sprayer:
http://ecx.images-amazon.com/images/I/41PD3g7sAdL.jpg
When it's all used up, I clean it with hot water, use some lacquer thinner to wipe away the painted-on label, and use it as a sprayer for Ortho weed-b-gon.
The Roundup I buy in that 5-liter ready-to-use sprayer contains:
- glyphosate (present as isopropylamine salt)
preservatives - 5-chloro-2-methyl-4-isothiazolin-3-one - 2-methyl-4-isothiazolin-3-one
Nothing else is listed. No other chemicals, no surfactants.
Could those "preservatives" function as surfactants?
According to this:
http://pmep.cce.cornell.edu/profiles/extoxnet/dienochlor-glyphosate/glyphosate-ext.html
=================Glyphosate is practically non-toxic to fish. However, Roundup was more toxic to fish than was glyphosate. An additive used in the Roundup formulation (modified tallow amine used as a surfactant) is apparently more toxic to fish than many common surfactants. For this reason, the formulation for use in aquatic situations (Rodeo) omits this ingredient. The surfactant is used to allow the compound to readily dissolve in solution and to keep the compound from balling up on the leaf surface. ================== This is wikipedia's page for polyethoxylated tallow amine surfactants:
http://en.wikipedia.org/wiki/Polyethoxylated_tallow_amine
==============Roundup Pro is a formulation of glyphosate that contains a phosphate ester neutralized polyethoxylated tallow amine surfactant; as of 1997 there was no published information regarding the chemical differences between the surfactant in Roundup and Roundup Pro.
The polyethoxylated tallow amine used as a surfactant in Roundup is referred to in the literature as MON 0139 or polyoxyethyleneamine (POEA). Presumably, the Roundup surfactant is a derivative of tallow, a complex mixture of fat from the fatty tissue of cattle or sheep.
POEA is 15% of Roundup formulations and the phosphate ester neutralized polyethoxylated tallow amine surfactant is 14.5% of Roundup Pro.
Surfactants are generally required to be used with glyphosate to allow effective uptake of glyphosate, which is hydrophilic, across plant cuticles, which are hydrophobic, and reduces the amount of glyphosate washed off plants by rain. ============== Does premixed Roundup available in the US contain surfactants?
I spray insecticidal soap on a few locust trees to kill aphids, and might start mixing it with Roundup and Weed-B-Gon as an experiment. This soap contains:
- Alkanolamine salts of fatty acids (25%)