Chrysanthemum White Rust (Puccinia horiana Henn.) is a serious fungal disease of chrysanthemum. It was first reported from China and Japan in 1895. It spread to all far east countries in the early 1900's, from there it spread to South Africa and Europe in the 1960's. It has since spread throughout Europe and has reached South America, Australia, New Zealand and Mexico. Localized introductions have occurred in United States and Canada.