The presence of glaucous juvenile leaves and glossy adult leaves in the canopy of the heteroblastic plant Eucalyptus globulus Labill., is a source of within-tree variation that affects herbivory by three psyllid species (Ctenarytaina eucalypti Maskell, C. spatulata Taylor and Glycaspis brimblecombei Moore) (Homoptera, Psyllidae). In no-choice field experiments with adult female psyllids in clip-on cages, we compared (1) leaf-settling, honeydew production, and survival of the Ctenarytaina species on juvenile and adult leaves of E. globulus, (2) leaf-settling and survival of G. brimblecombei on juvenile and adult leaves, (3) leaf-settling and survival of the three species on waxy (untreated) juvenile leaves and de-waxed (rubbed) juvenile leaves, and (4) leaf-settling and survival of C. spatulata on juvenile leaves from which wax was repeatedly removed. Leaf-settling by C. eucalypti was significantly greater on juvenile than adult leaves, however, honeydew production and survival were equal on both leaf types. In contrast, leaf-settling, honeydew production, and survival by C. spatulata were significantly greater on adult than juvenile leaves. Similarly, leaf-settling and survival by G. brimblecombei were significantly greater on adult than juvenile leaves. Wax removal from juvenile leaves significantly increased leaf-settling and survival of C. spatulata and G. brimblecombei. Although wax removal decreased leaf-settling by C. eucalypti, it did not affect survival. Repeated removal of regenerating wax from juvenile leaves did not affect leaf-settling or survival of C. spatulata. These results suggest that the epicuticular wax of juvenile leaves plays a role in resistance to C. spatulata and G. brimblecombei, however other unknown factors are probably also involved.