May 2016. Rust-like spots on breadfruit leaves in Majuro, Marshall Islands. Symptoms of Uredo artocarpi from Hawaii look different. The spots are only on the upper side of the leaf. It does not look like a serious problem at this stage.
It was diagnosed as Cephaleuros, not rust. It is an algal spot. There is a fact sheet in the app Pacific Pest and Pathogens. It can also be found from the Pestnet website. It is fact sheet no. 148 (Algal leaf spot).