Spruce broom rust of the broom. The main damage from the rust is simply overall volume and growth loss. The number of brooms as well as their proximity to the main stem can also play a role in determining the extent of the damage to the tree. "Chrysomyxa arctostaphyli" is an obligate parasite, and as with most other rust fungi diseases, spruce broom rust requires two different host plants to carry out its life cycle and is therefore referred to as heteroecious. The primary or aecial host of the rust is spruce ("Picea" spp.), and the secondary or telia host of the rust
Rust Rust Rust is an iron oxide, a usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture. Several forms of rust are distinguishable both visually and by spectroscopy, and form under different circumstances. Rust consists of hydrated iron(III) oxides FeO·"n"HO and iron(III) oxide-hydroxide (FeO(OH), Fe(OH)). Given sufficient time, oxygen, and water, any iron mass will eventually convert entirely to rust and disintegrate. Surface rust is flaky and friable, and it provides no protection to the underlying iron, unlike the formation of patina on copper surfaces. Rusting is the common term