rosy wrote:

T;hanks for your reply.....the photos are pretty good on Baldo's site
http://members.tripod.com/buggyrose/...wnymildew.html

but lacking in the one dead giveaway (IMHO) the bright red blotches on one
healthy cane, later turning purple, then black---the blotches growing
finally together. Then spreading to other healthy canes. I wish I'd
destroyed the first one when I discovered it, instead of trying to treat
it.... Once you've seen the blotches on the canes, I don't think you'd
mistake it for anything else......the markings on the leaves can be easily
mistaken for blackspot--only difference is dark purple edges.
The costs of those fungicides is incredible. Wish I knew where I got
it....but it looks like it is airborne anyway.

The reason I mention botrytis is that here in Marin County, botrytis is
everywhere and it's airborne. I know it's everywhere because all the
pavement roses in boulevard strips have massive cases, all up and down
Highway 101. One slightly eccentric rose nurseryman swears that when
he sprayed his greenhouse for botrytis, the stuff everyone thought was
downy mildew disappeared too. Just food for thought. It's a no-win
situation when DM is difficult to diagnose because the spores aren't
easily detected.

I have a bourbon that probably has downy mildew, complete with
inexplicable sudden twig death and maroon blothes on new leaves. I'm
about to destroy it. But it hasn't spread. I grow mostly disease
resistant roses, so that may be why. Do you grow a bunch of fragile
roses?

"Cass" wrote in message
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