Rose Rosette

Rose rosette disease, also known as witches’-broom of rose, is caused by a virus (Emaravirus sp.) that is spread by a very small, eriophyid mite. The disease is limited to plants in the genus Rosa but R. setigera, R. aricularis, R. arkansana, R. blanda, R. palustris, R. carolina and R. spinosissima are believed to be resistant. Its main host is the multiflora rose, which is considered a noxious weed throughout much of the United States. Interest in rose rosette has been generated by the threat to garden roses and its possible use as a biocontrol for multiflora rose.
Read more: http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/viruses/rose-rosette.aspx?source=Snapzu