Hypoxylon canker

Hypoxylon canker - Patches of grey fruiting bodies
  • Latin name: Entoleuca mammata J. D. Rogers & Y. M. Ju
  • French name: Chancre hypoxylonien
  • Division: Ascomycota
  • Class: Xylariales
  • Synonym(s): Entoleuca callimorpha Syd.,
    Entoleuca mammata (Wahlenberg) J. D. Rogers & Y. M. Yu,
    Geniculosporium sp. ,
    Hypoxylon blakei Berk & M.A. Curt.,
    Hypoxylon morsei Berk. & M.A. Curtis,
    Hypoxylon pruinatum (Klotzch) Cooke
Description

Micro-habitat(s)

Trunk, Branch

Distribution

Canada

Damage, symptoms and biology

Hypoxylon canker is a widespread and very serious disease of poplar, which can kill a large number of trees. The fungus penetrates the young bark through a wound on a branch near the intersection with the trunk. The bark then turns orange-yellow and becomes deformed. The following year, the infected zone expands and becomes rough and full of blisters and cracks owing to spore production. These spores do not cause new infection but are involved in producing a second type of sexual spores, ascospores, which will propagate the disease. The sexual spores are produced the third year after the infection is initiated on gray plate-shaped structures that measure a few millimeters in diameter, and these are located in the oldest part of the canker, which can be more than a meter large. When the canker gets wet, the spores are discharged and spread the disease.

Other information

In contrast with many other fungal diseases, periods of drought appear to favour new hypoxylon canker infections in affected stands. Since the infected trees tend to suffer stem breakage at the canker level, they should be removed anywhere there is a risk of damage in the event they are blown over.

Canadian Forest Service Publications

Hypoxylon canker

Information on host(s)

Main host(s)

Alders, balsam poplar, largetooth aspen, red maple, Sitka alder, speckled alder, sugar maple, trembling aspen, white birch, willow, yellow birch

Secondary host(s)

Apples, ironwood, oaks

Photos
  • Hypoxylon canker Dead bark of trembling aspen associated with Hypoxylon canker
  • Hypoxylon canker Perithecia embedded in stroma
  • Hypoxylon canker Fruiting structures of one stage of Hypoxylon mammatum, the cause of Hypoxylon canker.
  • Hypoxylon canker Breakage of trees infected by Entoleuca mammata is a common feature associated with Hypoxylon canker.
  • Hypoxylon canker Trembling aspen infected by Entoleuca mammata, the cause of Hypoxylon canker. Note the yellowish color of the bark on the canker margin.
  • Hypoxylon canker
  • Hypoxylon canker Grey fruiting bodies of the canker
  • Hypoxylon canker Leaf wilt on an infected poplar
  • Hypoxylon canker Bark cracks
  • Hypoxylon canker Patches of grey fruiting bodies
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