Question
I am finding orange mold on the bottom side of the leaves of some of my roses and it seams to be killing them. What is it and what can I do to stop it?

Answer
What you are describing is a fungus called rose rust. Some roses are prone to this particular form of disease. It's gets a hold and becomes bad because it is mainly on the undersides of the leaves which is hard to see. Any rose fungicide will do the job for you and solve the rust problem. Just follow the instructions for rust or black spot as both are a fungus. Keep a watch out on those particular roses because as I said they may be prone to rust and if they are they will always get it if you don't spray them. You will have to spray early in the spring with a fungicide to make sure they don't get it. Rust will make the leaves drop off but it really won't kill the rose. Hope this helps.