Abstract: The present invention relates to the use of behaviour modifying volatile plant compounds of rowan Sorbus aucuparia and apple Malus domestica for a determination of a population or controlling pest insects on apple, in particular apple fruit moth Argyresthia conjugella Zeller (Lepidoptera, Argyresthiidae) and codling moth Cydia Pomonella L. (Lepidoptera, Tortricidae). The compound 2-phenylethanol, only or in combination with other compounds, in particular anetole, efficiently attracting females and males of apple fruit moth A. conjugella. Other compounds identified from rowan and apple include p-anisaldehyde, )E)-beta-farnesene, farnesol, (Z)3-hexenyl 2-methylbutanoate, linalool and methylsalicylate efficiently attracting apple fruit moth, codling moth and other important pest insects of apple.