Under aerobic conditions, tau-fluvalinate is metabolised via hydrolysis and oxidation of the cyano group, breakage of the ester linkage and/or oxidation of the trifluoromethyl group on the aniline ring. The primary degradation products are anilino acid and 3-phenoxybenzaldehyde. Anilino acid is further degraded into haloaniline, and to a lesser extent to diacid, whereas 3- phenoxybenzaldehyde is further degraded into 3- phenoxybenzoic acid. The secondary degradation products are eventually converted into soil bound residues, CO2 and other minor products.