In nk.net Me wrote:
Three weeks ago I trimmed all my roses back because of rust, and they
are growing back well.

Even so, that's a bit extreme. Don't trim them. Spray is fine - rust
isn't THAT deadly to roses.

Try a milk spray if you're feeling daring. Works for me. One part full
milk to six parts water. Cover all leaf surfaces and let the sun turn
the milk proteins into a bacteria-toxic coating. Wonderful.

It also kills black spot and mildew. Great results with my garden. It
proves that some old wives' tales work!