The degradation of SYN545192 in dark, aerobic laboratory soil was very slow in the 5 soils studied. The only metabolite identified under these conditions was the desmethyl metabolite SYN546206. Levels of SYN546206 in all the laboratory soils were low but tended to increase gradually throughout the incubation to a maximum of 4.7% AR after 365 days in the readily extractable residues (maximum 5.6% when the residues from the harsh extraction were added). A number of other minor discrete unknown metabolites were also observed, none of which exceeded 5% AR. By the end of the aerobic soil incubations at 365 days after treatment (DAT) levels of evolved carbon dioxide and unextracted residues had reached maxima of 5.6% AR and 20.6% AR respectively, there were no significant differences between the radiolabels.