Many thanks to everyone who has given me feedback. This forum has been an enormous help to me over the years, but it's the helpfulness of people that makes it that way. Photos requested by Karen are posted below. Thanks a lot to Jim for bumping my post up.
I can report today that, after spraying with Cornell University formula yesterday afternoon, the rose bush looks much better. Unfortunately, I did not take a photo before I sprayed. As I recall, about half the leaves were curled, distorted. Most of them had white splotches all over them, but some were just curled with a little white on the edges. Today after the spraying, the white spots are dramatically reduced, on both the rose bush and the bee balm. Moses says the leaves will not reverse their appearance. I thought maybe my leaves were a little less distorted today, but as I say, I didn't take a photo; besides, much distortion is still there.
The Cornell University Formula I used is a common organic fungicide used on roses. You can find it on the internet in various versions. I use the precise proportions in the version cited by Field Roebuck in his book, Foolproof Guide to Growing Roses: 1 gal. water, 2 tblsp fine horticultural oil, 1 tblsp mild liquid soap (not a detergent), 1 heaping tblsp baking soda. Roebuck says it was determined by a researcher at Cornell to be at least as effective as chemical fungicides. This was later confirmed by studies at other institutions. I have found it an effective deterrent for black spot.
This photo was taken just a day or two before the mildew struck. I thought it looked healthy then, but now that I go back and examine the photo carefully, I can see the vague beginnings of splotches on the leaves, which had been flawless earlier in the year. One or two days later the leaves were a disaster.
This morning, after spraying yesterday, though many leaves remain shrivelled, I could find only a few that still had graphic white spots on them. I am thinking if the affected leaves don't improve any more, I will pull them off.
Q