Multiflora Rose
Rose Rosette Disease
Rose rosette disease was discovered in Canada in 1940. Over the years it has spread in the Midwest with a report in 1968 in Nebraska and then with the first report in Kansas in 1976. The disease is believed to be caused by virus or virus like organism which has double stranded RNA. The disease can be graft or mechanically transmitted but not by seed or fruits of rose species. It has been demonstrated to move from one plant to another by a microscopic eriophyid mite. These mites may be moved distances of several hundred feet by wind currents. The disease attacks most plants in the Rosa genus but with different degrees of susceptibility. Multiflora rose which is considered a noxious weed in the state of Kansas is highly susceptible to the disease.
In infected multiflora rose, symptoms are well pronounced in the spring with new growth as leaves emerge pink to red in color and branches grow in a pattern called a witches broom. As the disease develops, the leaves curl and turn yellow to brown and the tissue dies. Bushes will generally die out after 1 to 5 years of symptoms.
Figure 1. New pink to red leaf tissue associated with rose rosette.
Rose rosette is a naturally occurring biological disease which serves as a biological control agent of multiflora rose. In Kansas, rose rosette has been identified in many areas of central and eastern Kansas on both multiflora and cultivated roses. In pastures and fence rows in southeast Kansas, the disease has caused considerable dieback and reduced the populations of the unwanted multiflora. It is speculated to have stopped the establishment of multiflora rose in some areas of central Kansas.
Figure 2. Map of rose rosette in Kansas.
Unfortunately because of the infection in ornamental rose and hybrid rose, official biological programs of spreading the disease have not occurred in Kansas.
Landowners should be aware of these symptoms of rose and depending upon one's situation may want to encourage the disease by leaving infected multiflora rose plants in place and letting the disease take its toll. Rose enthusiasts should not plant cultivated roses near multiflora hedges or wild stands and rogue any plants with symptoms.
Rose rosette is not believed to be of any danger to commercially important related plants such as apples, plums, or cherries.