Résumé : 1Bioassays were carried out to examine differences in the feeding of a folivorous weevil, Stereonychus fraxini De Geer, on leaves from ash saplings with undamaged roots, and those with damaged roots. Beetles ate significantly more of the leaves of root-damaged saplings in a choice experiment.2A separate study of the effect of root damage on leaf toughness was carried out on a second group of ash saplings. Saplings with damaged roots had less tough leaves than control saplings. Decreased leaf toughness in hypothesized as a mechanism to explain the preference of weevils for leaves from damaged trees.3Both chemical and physical changes may occur in the tissues of ash trees in response to environmental stress such as drought and root damage.4Root damage caused by agricultural disturbance is hypothesized as a mechanism making mature ash trees in hedgerow ecosystems more susceptible to insect herbivores.