On Fri, 02 Jul 2004 18:11:48 -0500, in rec.gardens.roses you wrote:

I recently read an article in an organic magazine that suggested using
Baking Soda and horticulture oil as a remedy for black spots on roses.

Has anyone tried this, or do you know of a remedy that might work? I
have tried many fungicides including dormant sprays and still have a
HUGE problem.

I have had some luck using the following mixtu 1 tsp. baking soda,
1 tbs. horticulture oil, 1 1/4 tbs. Safer Insecticide soap per quart
of water. I believe both the soap and the oil help the baking soda in
adhering to the plant long enough for it to be effective.

The one thing is this: I haven't had a lot of luck rescuing a largely
affected rose bush, I have the best luck when I use this spray
preventively, or when the black spot hasn't gone too far, it seems to
be able to handle the problem. Once I had signficant black spot, it
seems like this spray could only do so much and I had to prune
drastically to get it back under control.

I learned from that episode, and since I've used this spray
preventively (2 years now) I haven't had a return of the black spot at
all, despite very good weather conditions for it.