Maybe a cane borer?

Cane borer if you were in my gardening area. Years ago, a rose lover was giving up his roses. I got his aged Elizabeth Taylor which had old woody canes and one had a hole in the middle. The bush was shaped like a broad U. Both canes continued to grow for five years and then, suddenly in rose years, the cane bored cane chose to die. The borer was long gone. To me, something similar appears to have happened to yours. That black around the bore hole is, maybe, a sign of age of the bore. I never got a new replacement cane to establish and I lost the second wooded stem about five years later.

I think Alana may have hit the nail on the head. From what I read apparently all you need to do is cut off the affected canes and the rest of the bush should be fine. Of course I'm no expert and have never seen this before, so hopefully you'll soon hear from others.

Oops, stillanntn6b's post appeared just as I signed off.

If it is a cane borer, I have read that you have to cut out the infected stems before they reach the roots. Hope that helps.

Thank You all! I found some pictures on the internet of cut canes the same size of mine, and the damage (hole in the middle) looks identical. My DH has agreed to help me tomorrow morning to cut the large cane down further, as the last emergency cut he made today (with me jumping up and down behind him) still had a hole in the middle. So glad it is not downey mildew!

Jackie