A resistant biotype of Peldon A1 of Alopecurus
myosuroides shows moderately enhanced metabolism
of 14C-fenoxaprop ethyl. However, in the more
resistant Lincs. E1, the metabolism rates of
fenoxaprop ethyl are intermediate between Peldon A1
and the susceptible Rothamsted biotype. Fenoxaprop
ethyl is hydrolyzed to the corresponding propionic acid
which undergoes further degradation to give polar
metabolites. The amounts of the metabolites depend
on the metabolism activity of the individual biotypes.
By wheat, barley, and crabgrass plants, fenoxaprop
ethyl is de-esterified to fenoxaprop, resulting in a
phytotoxic-free acid,
6-chloro-2,3-dihydrobenzoxazol-2-one, and
4-hydroxyphenoxypropionic acid.