METABOLISM OF CLOMAZONE HERBICIDE IN SOYBEAN

The metabolism of 2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone (clomazone) was studied in soybean plants grown in the greenhouse using C-14-radiolabeled clomazone at 1.1 and 2.2 kg of ai/ha. Isolation and identification of clomazone metabolites from soybean plants at 30 and 60 days after treatment indicated that the major metabolic processes included dealkylation of the parent chemical at the alkylamide linkage and conjugation of the resulting chlorobenzyl moiety to form its corresponding glycoside(s). Other minor metabolic routes included monohydroxylation of clomazone on either the aromatic or the isoxazolidinone moieties with subsequent formation of their corresponding glycosides. Additional polar metabolites that may result either from extensive degradation or from amino acid conjugations of parent compound or its intermediate metabolites were also observed.