Here in Florida, our hot, humid, and rainy weather make conditions ripe for Plumeria rust in the late summer. It turns the leaves yellow and brown, making a mess when they fall, and causes heartache in those of us who love and tend to our Plumeria like cherished friends. Ultimately it does not harm the plumeria, they still bloom, and new rust-free leaves will continue to emerge until the first cold days of winter. A little effort on our part, like pulling affected leaves, occasional spraying with chemicals meant to deter rust, keeping good air flow around the plants, and not composting rusty leaves, usually keeps the rust manageable throughout the blooming season.