Herbivores do not attack plants in the field uniformly. Using a common garden and a greenhouse experiment, the role of plant genotype in influencing the resistance and tolerance of Salix cordata to a specialist herbivore, Alatica sulplicata, was examined. Resistance was measured by the number of naturally colonizing adult and larval beetles. There were significant differences in beetle density among genotypes throughout the study period. This genetic variation in resistance was not caused by differences in plant size or trichome density. The tolerance of plants was measured by plant height, stem diameter and number of leaves produced following a given level of defolation. Clone genotypes signficantly differed with respect to height and number of leaves produced in response to defoliation. There was no relationship between resistance and tolerance for the nine clones studied.