It appears one of my Knockout Roses has Rose Rosette.
Rose Rosette (RRD) is a viral disease of roses that is transmitted by the microscopic eriophyid mite or by grafting. This disease was first described in the early 1940s and it has emerged as one of the most devastating diseases of roses … one with no known cure.
- Common on the wild multiflora rose which was introduced in 1866 as root stock
- Most rose species and cultivars are susceptible
- Infected rose plants often die within a few years
- Roses are the only plants known to be susceptible to this disease
- Can spread to other roses
- Witches’ brooms or clustering of small branches
- Small distorted leaf growth
- Leaf reddening
- Excessive thorn production (Unusually soft and pliable red or green thorns)
- Thickened stems
- Rapid stem elongation
What To Do About It
- Get a diagnosis from your country extension agent (Purdue office in Danville, IN, call 317.745.9260).
- Dig the bush and remove all roots.
- Dispose of bush (Burn if you can burn in your area, if not, double bag and throw in trash.)
Our growing season has been so different from anything we experienced–started out with very early spring, then to moved to frost damage and now we are dealing with drought. So, it took me a while before I realized what was going on.
Today we took a section of our diseased rose to our County Extension Agent. If you live in my area I would highly suggest you take advantage of the wonderful resource we have in Danville. The facilities are brand new and the very capable staff is eager to help.
Now we wait for a full report due back next week. We hope it is not RRD but we’ll soon know for sure. I’ll keep you posted.