Q.What Disease Is Killing My Roses?
Can you please tell me what disease this is and if i am dealing with one or two diseases at the same time? The symptoms seem to point to downy mildew and stem canker. But I have never encountered a description of the white circles which always appears on the sick canes. They drive me crazy. Just a few, and not grouped together. I can scrape them off with my fingers easily. Then the cane becomes yellow and develops cankers. At first, the leaves might not show symptoms, or they have different kind of symptoms like in the pics. It affects all canes, old and young. Oh, and sometimes the base of the leaflet develops a dark growth around it. I think the problem has started with a diseased potted rose I have brought into the garden last year. The symptoms appeared by the end of july and august. I had to cut most roses to the ground, then sprayed with fungicide. In spring, they rebounded nicely and I was happy, but now the same thing is happening (at the same time as last year) and the decline is very fast. Have I been blessed with the two most dreaded diseases at the same time? It looks like I will lose all my roses to this and it’s heartbreaking. Almost all the roses are affected, in different parts of the garden.
Certified GKH Gardening Expert
It could be anthracnose and downy mildew going on. Looking at your photos and text and comparing with disease descriptions, those seem closest. The good thing is the fungicides are appropriate for several rose diseases, not just one. For example, fungicides approved for anthracnose also are approved for black spot and Cercospera leaf spot. This article should help:
