The invention relates to 2-imino oxyphenyl acetic acid derivatives of formula (I) in which the substituents and the index have the following meanings: R is C(CO2CH3)=NOCH3 (Ia), C(CONHCH3)=NOCH3 (Ib), C(CONH2)=NOCH3 (Ic), C(CO2CH3)=CHOCH3 (Id), or C(CO2CH3)=CHCH3 (Ie); R is cyano, nitro, halogen, alkyl, alkyl halide or alkoxy; m is 0,1 or 2; R is hydrogen, cyano, hydroxy, halogen, alkyl, alkyl halide, alkoxy alkyl, alkoxy, alkoxy halide, alkylthio, cyclopropyl, alkenyl, optionally substituted aryloxy alkyl, benzyl or benzyloxy; R is hydrogen, cyano, optionally substituted alkyl, alkenyl, alkinyl, cycloalkyl, heterocyclyl, aryl and hetaryl, optionally substituted alkoxy, alkenyloxy, alkinyloxy, cycloalkoxy, heterocyclyloxy, aryloxy and hetaryloxy, optionally substituted arylthio and hetarylthio; -Q-C(R )=N-Y -R or -Q-O-N=CR R ; R and R together with the carbon atom to which they are bound, are an optionally substituted four to eight-membered ring which can contain in addition to carbon atoms one or two oxygen atoms and/or sulphur atoms and/or NH- and/or N(C1-C4-alkyl)groups; wherein R and R are not simultaneously bound via heteroatoms to the carbon atom. The invention also relates to the salts of said derivatives, methods and intermediates for their preparation and use thereof.