Feeding and oviposition on different parts of mile-a-minute weed, Polygonum perfoliatum L. (Polygonales: Polygonaceae), by Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae), a potential biological control agent for the weed, were studied in quarantine. An additional experiment was conducted to test the effects of different levels of simulated damage by R. latipes on P. perfoliatum growth, survival, and reproduction. Female weevils consumed more P. perfoliatum overall than males and selectively fed on capitula more than on ocreae or leaves, whereas males fed more on ocreae than on leaves or capitula. More eggs were also laid on capitula than on other plant parts. Female feeding preference is probably because of the high protein content of the capitula, because protein is required for continued egg production, whereas males may maximize their reproductive success by feeding low and close to P. perfoliatum stems to intercept females as they emerge from pupation in the soil and ascend the plants to feed. The feeding and oviposition preferences of female R. latipes for plant capitula suggest that host specificity tests for this species should be conducted with plants that are flowering. Damage that simulated the effect of R. latipes larval feeding caused plant mortality when it was initiated on small P. perfoliatum plants and reduced biomass and seed production when it was initiated on larger plants. Thus R. latipes could have a substantial impact on P. perfoliatum if the weevil is released into the weed’s introduced range in North America.