I haven't seen that on any canes I've cut and I've cut a lot with symptoms. I wonder if that coloration is because of less than pristine secateurs (on a single blade) because of the pattern it exhibits. Back when Epstein and Hill wrote the Etiology of RRD paper, they mentioned staining of canes of affected roses. But they were talking about after cutting the cane and applying stain to that surface. rose canes stain with iodine to show the presence of starches - which meant that there was a difference between those rose canes and totally infected ones where there was no starch-sugar conversion of (and related poor winter survival). (See the test for starch of a match stick and medical grade iodine.) At Jim Amrine's lab, he had some iodine and I put in on a stem that had 1) mites and 2) RRD symptoms and the iodine stain didn't work the way it was supposed to.

What I did was to cut off the diseased growth below the point on the cane that it appeared on. Any new growth from that cane has not shown any more symptoms with the exception of General Cavaignac. It was asymptomatic for a whole year but started showing it again. I cut it off and watered it with more aspirin, and it has been okay. I am suspecting a reinfection rather than a relapse because it is close to the infected Dr. Huey. I have used an aspirin spray. I have used one 325 mg pill per 3 gallons of water, the size of my tank sprayer. I do have to watch it carefully because I have seen foliage burn on some of the plants doing this. There is increased blackspot resistance from this treatment, but again foliage burn can be a risk. I have also been using the harpin material for good blackspot control, but it does not appear to have much influence, if any, over rosette. I think that early detection and treatment is a key help for this problem, like cancer. If it gets too far along, the plant will probably be lost. I am also wondering if an interferon-like material would be a good treatment option if it could be either sprayed or maybe watered into the ground. I hope these observations help this situation somehow.

This is something of a mystery disease, by the way. Not really a virus, but not anything else, as far as I know. The reason why removal of the entire plant is suggested is very simple. The pathogen can be transmitted from a sick plant to healthy ones via a type of mite. By allowing infected plants to remain in your collection, you put the others at risk. Best to make absolutely sure that this is what your roses have, and then bite the bullet. Removal of only the parts of the plant that are symptematic does not resolve the issue. Good luck!

As the originator of the one cane removal technique, I can tell that it works sometimes. Sometimes is a whole lot better than never. One scientist has said to me that how can you tell it doesn't come back. I have responded to him, after ten years of good healthy growth, that should be enough. I don't think it works for fall infected hybrid teas as I didn't save any of mine that got fall infections that I saw the following spring. The other thing I do is check with a microscope to see if the infected bush is teaming with eriophyid mites. Mine aren't. I don't use insecticide or acaricides and I see beneficials at the microscopic and visbile to the naked eye sizes. Here's my ebook about RRD/RRv for those who haven't seen it before. Rose Rosette E-book Ann