None of my plumeria, some 75 plants, get much in the way of rust. Just because I don't like fungal diseases on any of my plants, I did preventively spray them in late spring last year with Bayer 3 in 1. Because that seemed to work well, and before dormancy approached, I re-sprayed in late summer. That was the first and only year I have done this though. Because I have more plants now, and some seedlings/rooted cuttings that are maturing, I am going to do that same spraying this time around. If I had heavy infestations of rust, spider mites, or harmful insects, I would apply this every other week until I saw control.
The 3 in 1 is actually on my "buy" list when I visit Lowe's again.
