I am guessing but it is probably impossible to control all of the rust in southern gardens. I know a lot of sellers have a disclaimer that if you are afraid of getting rust don't bid on their auctions. I have also gotten rust from a couple of southern plants but I knew that was a possibility before I bid. Our winters kill it though so I wasn't that concerned about it.
Your climate certainly is more likely to develop rust on plants. I heard that rust spores can come into your garden from 30 miles away due to the wind carrying them. I would remove as much of the infected parts as possible and spray the rest.
