We investigated differences in native and exotic Phragmites australis (common reed) resistance to native and exotic insect herbivores. In field studies, a native skipper (Poanes viator), exotic shoot flies (Lipara sp.), and an exotic aphid (Hyalopterus pruni) fed on both native and exotic plants. An exotic rhizome feeding moth (Rhizedra lutosa) fed only on exotic plants. In laboratory studies, P. viator and R. lutosa completed development on both native and exotic plants, but P. viator survival and development was significantly greater on native plants. In greenhouse studies, H. Pruni population densities were significantly greater on native plants, and their feeding damaged or killed most native plants; exotic plants were relatively unaffected. Exotic insects may be influencing the interactions between native and exotic P. australis and possibly contributing to the decline of the native subspecies.