Green Light on Herbicides
A Roundup on
Glyphosate
History, Use, Issues, and Alternatives By Jeffrey Derr, Ph.D., Professor of Weed Science, Virginia Tech
G
lyphosate has been in the news quite a bit recently. You probably have seen the ads on television concerning glyphosate and human health. In this article I discuss some background infor- mation on this herbicide as well as scientific reports on toxicity of the chemical.
A. What is glyphosate? The glyphosate molecule (Figure 1) is similar to the amino acid glycine. The chemical name is N-(phosphonomethyl) glycine, a relatively small molecule compared to newer herbicides. It is the active ingredient in products such as Roundup PROMAX,
as well as in generic products sold under a variety of trade names. Since the chemical is off patent (patent expired around 2000), other companies besides Monsanto/Bayer can sell this herbicide under their own trade name. Some examples of other trade names for products that contain glyphosate include Accord, Gly Star Pro, Glyphomate 41, Razor, Rodeo and Touchdown, among others.
B. Formulation The initial formation of this herbicide was an isopropylamine salt of glyphosate, which is still widely used, although other salt formulations are available now, such as the potassium salt and
Figure 1: glyphosate isopropylamine salt
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July/August 2019
