This is my first experience with plumeria and I need help identifying these spots so I can treat them. I've had this plant maybe a month or two and these brownish spots have started spreading throughout the leaves. I thought it might be rust, but there are no spores on the bottom of the leaves. Is this some other type of fungus? Pest damage? Treatment suggestions? Please help!!!

It could be a fungus. Could you let us know where you are located? In South Florida we get so much rain this time of year that the leaves are inevitably ugly... I try not to worry about it too much, it's all about the blooms for me!!