Every late winter here in N GA, I've got to prune my RMJ's and remove small branches that develop fungal galls. The galls are discrete swellings on the stem that burst open with the orange goo after the first few warm spring rains. Prophylactic spraying in the spring and summer keeps C-A rust mostly at bay, but as others have pointed out, it's already everywhere in the landscape so it'll always be an issue. My advice is to not keep juniper species that are prone to the disease, like ERC. I'm currently grafting shimpaku on 2 of my 3 RMJ, and one of the motivating issues to do so was the native foliage's susceptibility to C-A rust.