Albugo occidentalis Albugo occidentalis Albugo occidentalis, the causal agent of Spinach White Rust, is an oomycete plant pathogen, although some discussions still treat it as a fungal organism. "Albugo occidentalis" is one of the most important spinach diseases in North America, found throughout the United States east of the rocky mountains. The economically important host of "Albugo occidentalis" is spinach (Spinacia oleracea); although the oomycete has also been reported to affect plants of the genus Chenopodium, the genus including the crop plant quinoa. This pathogen causes white rust or white blister of spinach. It is unrelated to the basidiomycete rusts biologically, but
Rust for corrosion of iron and its alloys, such as steel. Many other metals undergo similar corrosion, but the resulting oxides are not commonly called rust. Other forms of rust exist, like the result of reactions between iron and chloride in an environment deprived of oxygen. Rebar used in underwater concrete pillars, which generates green rust, is an example. Although rusting is generally a negative aspect of iron, a particular form of rusting, known as "stable rust," causes the object to have a thin coating of rust over the top, and if kept in low relative humidity, makes the "stable" layer