However, like all good things, they must come to an end. Case in point: Several calls and many rose specimens in the disease diagnostic lab with weird, red, thorny growth.
All the Knockouts here at our office were removed due to this problem, a disease problem. You might say ‘How? Knockouts are disease resistant!’.
Nope, sorry, they are not resistant to rose rosette.
The cause of rose rosette disease was thought to be a virus, but recent research suggests that a phytoplasma infection is responsible for the symptoms. In nature, it is spread by a tiny eriophyid mite.
Disease management. Infected plants must be removed and destroyed so that the pathogen is not spread to healthy plants nearby. Care must be taken to avoid scattering disease-carrying mites to the other plants. Early detection is essential. Rose rosette disease is normally systemic in the plant, but at the first indication of infection on a shoot, it might help to clip off the affected shoot in hopes that the rest of the plant is still unaffected. Multiflora rose could be a reservoir for the disease so they should be removed from the neighborhood of cultivated roses.