Sethoxydim kills grasses by preventing the synthesis of
lipids, but it has little or no impact on broadleaf herbs or
woody plants. Sethoxydim is readily degraded through
microbial metabolism and photolysis, and possibly by
hydrolysis. Numerous degradation products have been
identified, some of which are also toxic to plants. The
average half-life of sethoxydim in soils is four to five days,
but half-lives can range from a few hours to 25 days.
Because sethoxydim is water-soluble and does not bind
strongly with soils, it can be highly mobile. No reports,
however, were found referring to water contamination or
off-site movement by sethoxydim. Sethoxydim is of
relatively low toxicity to birds, mammals, and aquatic
animals, and has little noticable impact on soil microbe
populations. An oil adjuvant or non-ionic surfactant
should be used to facilitate absorption of sethoxydim by
plants.