AUBURN, Ala.- A devastating rose disease is now widespread in north Alabama. Rose rosette disease, identified in Alabama in 2010, is most severe in the Tennessee Valley area. First identified in California in the 1940s, it has spread east over the last 70 years.
From the first report of rose rosette disease, scientists made little progress in identifying the cause of the disease. However in recent years, the disease has conclusively been determined as being caused by the Rose Rosette Virus.
Dr. Jim Jacobi, a plant pathologist with the Alabama Cooperative Extension System based at the Birmingham Botanical Gardens, said that roses are the only plants known to be susceptible to this disease.
Rose rosette disease is spread by eriophyid mites. The mites are yellow to brown in color and are three to four times smaller than an average sized spider mite. The mites are found on tender new growth on buds and between stems and leaf petioles. Most infections occur in the spring between April and June. Wind currents can be a factor in the spread of the disease by carrying the mites over long distances.
The symptoms of rose rosette disease can differ depending on the cultivar and can even resemble herbicide injury.
Rose Rosette Symptoms
- Witches broom(clustering of small branches)
- Small distorted leaf growth
- Leaf reddening
- Excessive thorn production and pliable red or green thorns
- Thickened stems
- Rapid stem elongation
Jacobi said there is currently no cure for this disease and affected plants must be dug up and removed, including the roots. The virus can survive in living root tissue. You must remove the roots to prevent root suckers from serving as reservoir for the disease.
He recommends that you bag up the infected plant and roots and throw it away. Do not try to compost the plant, which has the risk of spreading the disease.
To try to control the disease, space plants so that canes and leaves do not touch each other. If you notice the symptoms, prune out the entire infected stem. It may save the plant by stopping the spread of the disease before it moves systemically through the plant. There is only a 50:50 chance of the plant surviving using this method. If more than one stem shows symptoms, the entire plant must be removed.
He said that controlling mites may help to reduce the spread of the disease.
“Products for the control of eriophyid mites include Avid, Talstar and Sevin,” said Jacobi. “Sevin is effective against the mites, but it may increase spider mite problems.”
For more information on this and other diseases that may affect your garden, visit the Alabama Extension website or contact your local extension office.
- Rose Rosette Disease–Alabama Extension publication
- Rose Rosette Disease–Alabama Extension presentation
- Freqeuently Asked Questions About Rose Rosette Virus–Clemson Extension
Based on proven Master Gardener training and seasoned with university research, the “Gardening in the South” series of books is packed with information, tips and tricks to being a successful Southern gardener.
Have a gardening question? Call the Master Gardener Helpline. To reach the helpline, dial 1-877-252-GROW (4769).