Agriculture Reference
In-Depth Information
years, and they are marketed primarily for use in vegetable and flower gar-
dens, landscapes, lawns, and areas such as driveways. Chemically, herbicid-
al soap products are salts of long-chain fatty acids. They act by damaging
the outer layers of green, succulent plant tissues, causing the affected plant
parts to wilt and die. They are not effective against woody stems or trunks
and do not damage roots or other underground organs. The following dis-
cussion of one particular herbicidal soap, ammonium nonanoate, provides a
good description of this type of product.
The following excerpts on the use of ammonium nonanoate are taken
from the
Ammonium Nonanoate (031802) Fact Sheet Related Information
,
issued by the U.S. Environmental Protection Agency (EPA) in November
of 2006. This fact sheet applies to a particular herbicidal soap product
presently approved by the Organic Materials Review Institute (OMRI).
Ammonium nonanoate is closely related to other salts of fatty acids
known as soap salts. The active ingredient is a C9 saturated-chain fatty acid
soap salt. It . . . is a clear, colorless to pale yellow liquid with a slight fatty
acid odor. Ammonium nonanoate is a non-systemic, broad-spectrum contact
herbicide that has no soil activity. . . . Ammonium nonanoate is to be used for
the suppression and control of weeds including: grasses, vines, underbrush,
annual/perennial plants, including moss, saplings, and tree suckers.
Ammonium nonanoate can be applied using all standard methods of li-
quid herbicide application, including hand-held, boom, pressure, and hose-
end sprayers. For use, the concentrate is diluted with water to a specified
concentration.[ . . .] For the active ingredient to be effective, the leaves of un-
desirable vegetation must be uniformly sprayed and thoroughly wetted. Ap-
plication can be repeated as often as necessary to obtain the desired control.
The Agency concludes that no risks to human health will be expected
from the use of ammonium salts of higher fatty acids (C8-C18 saturated
and C18 unsaturated), based on their low toxicity and the fact that residues
from pesticide use are not likely to exceed the levels of naturally occurring
or intentionally added fatty acids in commonly eaten foods. Since ammoni-
um nonanoate has the potential for eye, skin, and mucosal irritation [mu-
