Multiflora rose (Rosa multiflora), a nonnative shrub native to East Asia, has established throughout the Midwestern, Southern and Eastern United States. While this plant was intentionally introduced as an ornamental plant and for wildlife habitat, it has become one of the more common invasive plants in the eastern United States as it infests over 45 million acres (Underwood et al., 1996). Currently multiflora rose dominates pastures and edges of forests within the southern part of Wisconsin. Besides losses in productivity in pastures, multiflora rose greatly reduces the accessibility of these areas for recreation due to the creation of impenetrable thickets.

Recently a disease native to North America called rose rosette disease (RRD) has been found infesting multiflora rose plants within southwestern Wisconsin. This disease was first discovered in Canada in 1940 and currently it can be found in Alabama, Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky, Maryland Missouri, Nebraska, Oklahoma, Ohio, Pennsylvania Tennessee, Texas, West Virginia, and Wisconsin (Armine, 2002). Its distribution in Wisconsin is limited, but observations indicate that it is spreading. Currently infested multiflora rose plants have been seen in Vernon, Crawford, Grant, Richland, Sauk, Iowa, Lafayette, Green, Racine, and Dane counties (personal communication J.Doll, P. Pelliterri, A. Barta). This disease is fatal to multiflora rose as infected plants they die within 5 years (Epstein and Hill, 1999; Armine 2002). While no tests are currently available that verify if plants are infected, symptoms on multiflora rose are quite distinct making identification easy. Symptoms include a red coloration of the underside of leaf veins, elongated shoots, an increase in the number of thorns, and a proliferation of lateral buds on shoots that produce many reduced and malformed leaves (witches’ broom).