As another poster just noted, it came on SUDDENLY!
I went on-line to read up, and found most entries fairly similar.
"Rose rust can be treated by pruning out spring infections as soon as they emerge and removing fallen leaves promptly during autumn. (If infections are persistently troublesome, it may be that the cultivar concerned is unusually susceptible, and it may be necessary to replace it.)
Chemical treatments for rose rust are fungicides containing mancozeb, myclobutanil, penconazole and triticonazole all to be sprayed in spring and summer.
Neem oil diluted and sprayed on leaves is an effective organic treatment for controlling rose rust and powdery mildew ."
Another site says:
"Preventing Rose Rust
Rose rust, a condition that affects rose plants, is one where dark spots of fungus develop on leaves and blossoms. Rose rust disease occurs most frequently in humid environments where the fungus grows. The disease is spread when winds blow fungal spores onto rose plants, where they attach and develop. Identifying and Treating Rose Rust
Monitor your roses carefully for signs of rose rust. The fungus may be dark yellow to brown in color and will appear in small, pea-sized patches all over the plant. Check underneath leaves for signs of rose rust disease as well.
Clean off visible spots of fungus from your rose plants before treating them with a fungicide spray. Remove any parts of the plant that contain dark spots, as these may spread to other areas if not destroyed. Treat the affected plants with fungicide once every 10 to 14 days as needed. Rose rust treatment will be most effective if you pick off all infected leaves and stems first.
Rose rust disease is easily treatable, but takes a careful eye to notice the fungus before the disease is widespread. Monitor your roses carefully for signs of rose rust disease and then act quickly when you detect any symptoms of the disease.
Read more: http://www.doityourself.com/stry/preventing-rose-rust#ixzz0pub0q670 "
Would appreciate your input on the following:
1. this is So. Cal Coastal. Can I still spray some of those horrible-sounding chemicals?
2. There's pro and con about effectiveness of Neem oil. Your opinon/ experience?
3. I didn't notice any "spring infections"; the roses looked very healthy. This came on suddenly. "Should" I apply something in Spring, regardless?