Another fall season is here! Football, cooler weather and county fairs are what I think about when fall arrives. Last month I was invited to the Rosemark Country Fair to answer gardening questions at the UT-TSU Extension booth. In order to attract people to the table, I brought along a few samples. One of those samples was a rose plant from my garden that had the dreaded rose rosette disease (RRD). This diseased rose really got their attention!
Rose rosette disease is believed to be caused by the Rose rosette virus. It has attacked wild multiflora roses (Rosa multiflora) for years. It is also lethal to ornamental rose species and cultivars. The eriophyid mite spreads the disease. These mites do not have wings and crawl from plant to plant. The mites can also migrate via the wind, from infected to healthy plants.
The symptoms are easily recognizable. One indication of rosette disease is the rapid elongation of new shoots, followed by the development of clustering small branches or witches’ broom. The leaves within the cluster of small branches are small, distorted and may have red pigmentation. Depending on the species or cultivar, the canes develop excessive growth of red or green thorns which are soft and pliable. Sometime those canes can be thicker than the parent cane. Rose plants that are infected with this disease often die within one or two years.
Early detection is the key in controlling this disease. If it is suspected that there is a presence of RRD, remove and destroy that plant immediately. If burning is permitted this should be done to destroy the diseased plant. In areas where burning is not allowed, dig up that plant, bag it and put it in with the trash. Do not allow those diseased plants to remain in beds with healthy roses. Avid (insecticide) is registered for control of eriophyid mites on roses but the use of miticides in the absence of cultural controls in not recommended.
If you grow roses like me be sure to inspect them often. Look for those symptoms that were discussed earlier. So far I have lost three roses to this dreaded disease and it is currently working on rose number four. I haven’t completely gotten rid of that fourth one just yet because it makes for such a prize sample. Just ask the folks who visited with me at the Rosemark Fair!
Until next time, happy gardening!