In article , rosy wrote:

The last few years I've had losses, most certainly to "Downey Mildew".....
(not powdery mildew) with red blotches on the canes, and general malaise of
the plant...... spraying with Daconil....... it appears to spread.

Is there anything I can do besides start over? I have over 100 roses.

Don't have any sure experience with DM, but there is information
available several good websites. I do know that you should make
absolutely sure you are dealing with downy mildew because the cane
symptoms can look a lot like botrytis and canker. And the cost of the
fungicide is out of this world.

http://www.rosecare.com/diseases.html

http://hortipm.tamu.edu/publications/Pathup1.html

http://www.primaryproducts.com/files/specials.htm

http://www.ces.ncsu.edu/depts/pp/not...02/rosebbs.htm