The present invention relates to the use of known and novel N (2 substituted 2 phenylethyl)carboxamides and N (2 substituted 2 phenylethyl)thiocarboxamides for the control of plant damaging nematodes in agriculture and further relates to novel N (2 substituted 2 phenylethyl)carboxamides and N (2 substituted 2 phenylethyl)thiocarboxamides processes and intermediate compounds for their preparation their use as nematicides and their use as anthelmintics against endoparasites in animals and humans compositions containing such compounds and methods for the control of nematodes and helminths.