Canna rust a medium threat to biosecurity and agriculture. The Canna rust damages the crop and can impact all of its potential uses by damaging photosynthetic material and reducing plant productivity and value. In the United States it is a popular ornamental for home gardens. The rust lowers the value of lilies for sale and can kill canna plants that home gardeners are trying to grow themselves. Canna rust Canna rust is a fungal disease of canna caused by "Puccinia thaliae". Symptoms include yellow to tan spots on the plant's leaves and stems. Initial disease symptoms will result in scattered sori (clustered
After-rust After-rust After-rust is a form of rust which sometimes develops on a non-ferrous metal surface when that surface has been finished, deburred, or cleaned with a carbon steel brush or steel wool. It is caused by microscopic deposits of the steel which become embedded in the metal surface and which over time begin to oxidize. This oxidation causes the surface to become dull and may impart a brown color to it. After-rust can be avoided by cleaning such surfaces only with non-ferrous brushes/ wools including rustless bronze, aluminum, and stainless steel wool and nonferrous wools such as those made of