Fir-fireweed rust

Fir-fireweed rust - Fruiting of <em>Pucciniastrum epilobii</em>, the cause of a needle rust of balsam fir, on infected needles.
  • Latin name: Pucciniastrum epilobii G. Otth
  • French name: Rouille du sapin et de l'épilobe
  • Division: Basidiomycota
  • Class: Uredinales
  • Synonym(s): Pucciniastrum abieti-chamaenerii Kleb.,
    Uredo fuschsiae Arth. & Holw., hom. Illeg.
Description

Micro-habitat(s)

Needle, Leaf

Distribution

Canada

Damage, symptoms and biology

The fungus causes fir needles to wilt and drop prematurely. In severe infections of young trees, the disease can cause a severe reduction in growth. The fungus lives on two hosts in alternation, balsam fir and fireweed Epilobium sp., a plant with purple, lilac coloured flowers. While living on its fireweed host, the fungus occasionally infects other ornamental plants in the same family. In spring, small white blisters develop on the lower surface of balsam fir needles. The yellow-orange spores discharged from these blisters end up infecting the young shoots of fireweed plants.

Other information

Fireweed is a beautiful wild plant but it should not be naturalized in our gardens because it is highly invasive and serves as the primary vector for the disease. In Christmas tree plantations, it is important to remove the alternate host to prevent the disease from appearing in the crop trees.

Canadian Forest Service Publications

Fir-fireweed rust

Information on host(s)

Main host(s)

Amabilis fir, balsam fir, grand fir, subalpine fir, white fir, willow-herb

Photos
  • Fir-fireweed rust Uredinia of P. epilobii on the lower surface of a fireweed leaf
  • Fir-fireweed rust Fireweed, the alternate host of Pucciniastrum epilobii, the causal agent of a needle rust of balsam fir.
  • Fir-fireweed rust Fruiting of Pucciniastrum epilobii, the cause of a needle rust of balsam fir, on infected needles.
  • Fir-fireweed rust Rust on needles
  • Fir-fireweed rust Rust on needles
  • Fir-fireweed rust Rust on needles
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