Spruce broom rust

Spruce broom rust - Spruce broom with sporulating aecia on needles
  • Latin name: Chrysomyxa arctostaphyli Dietel
  • French name: Rouille - balai de sorcière de l'épinette
  • Division: Basidiomycota
  • Class: Uredinales
  • Synonym(s): Peridium coloradense (Dietel) Arth. & F. Kern
Description

Micro-habitat(s)

Needle, Leaf, Branch

Distribution

Canada

Damage, symptoms and biology

The infection causes the formation of witches brooms, with yellowed needles. Orange spores appear on the needles in late summer.

Spruce brooms are often associated with stem deformations, reduced increment growth, broken tops, and tree mortality. Rust brooms also serve as infection courts for decay fungi such as Phellinus pini contributing to increased levels of damage.

Other information

The brooming symptoms caused by C. artcostaphyli could be confused with mistletoe infections. However, distinguishing features of the rust are the complete loss of needles in the winter and the yellow-orange colour of the broom in the spring and summer.

Canadian Forest Service Publications

Spruce broom rust

Information on host(s)

Main host(s)

Black spruce, blue spruce, common bearberry, Engelmann spruce, Norway spruce, red spruce, Sitka spruce, white spruce

Photos
  • Spruce broom rust Spruce broom associated with a dead top caused by Chrysomyxa arctostaphyli. The broom appears dead, with no needles, during the winter months
  • Spruce broom rust Spruce broom with sporulating aecia on needles
  • Spruce broom rust Spruce broom with sporulating aecia on needles
  • Spruce broom rust Sporulating aecia
  • Spruce broom rust Kinnikinnick, the telial host of C. arctostaphyli. Discoloured spots on the upper surface of the leaves indicate the presence of telia on the lower surface
  • Spruce broom rust Telia on the lower surface of kinnikinnick leaves
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