The invention relates to oximes of the formula ##STR1## wherein n is 0, 1 or 2 and m is 0 or 1, and wherein Ar is a phenyl radical ##STR2## a naphthyl radical substituted by R.sub.2 and R.sub.3, a 5- to 10-membered heterocyclic radical which contains not more than 3 identical or different heteroatoms N, O and/or S, and which is substituted by R.sub.2, R.sub.3 and R.sub.4 and can be substituted by oxo or thiono, or, if m is O, Ar is a radical R--CO--, wherein R is a radical --OR.sub.5, and Q is a radical C.sub.a H.sub.2a --R.sub.8, wherein a is an integer between 1 and 6, while R and R.sub.8 are as defined in the description of the specification. These compounds can be used for protecting plant crops from the action of aggressive agrochemicals.