Mineral nutrient levels in tissues of the domestic shrub rose (Rosa rugosa Thunb.) were examined following gall induction by the cynipid wasp Diplolepis spinosa (Ashmead). Higher levels of Cu, Zn, Fe, Mn, and Ni were found in the galls, leaves protuding from the galls, and stems to which galls are attached than were found in normal stems and leaves, indicating that cynipid galls alter the nutritional status of their hosts. Cynipid galls must be removed or controlled because the stress they cause will increase the vulnerability of roses to attack by other pestiferous insects.