Nectria canker

Nectria canker - Fruiting bodies of <em>Nectria galligena</em>, the causal agent of Nectria canker, on the margin of a canker on white birch.
  • Latin name: Neonectria galligena (Bres.) Rossman & Samuels
  • French name: Chancre nectrien
  • Division: Ascomycota
  • Class: Hypocreales
  • Synonym(s): Cylindrocarpon heteronema (Berk. & Broome) Wollenweb,
    Dialonectria galligena (Bres.) Petch,
    Nectria galligena Bres.,
    Neonectria ditissima (Tul. & C. Tul.) Samuels & Rossman
Description

Micro-habitat(s)

Trunk

Distribution

Eastern Canada

Damage, symptoms and biology

In wet weather, the causal pathogen infects wounds on the tree (leaf scar, broken branch, crack in the bark). Once established, the pathogen colonizes the tissues of the living bark and begins spreading toward the middle of the tree. A canker then forms on the trunk and as it matures, it causes the bark to split open. The tree tries to seal off this wound by producing a ridge of callus tissue around the scar. The infection, rarely lethal, lasts a number of years, and a state of equilibrium is established between the spread of the fungus and callus formation. After the callus tissue has been growing for a few years, a characteristic target-shaped scar appears. The disease often causes bole breakage, providing a point of entry for decay fungi.

Other information

The orange-red fruiting bodies of the fungus can frequently be seen on the bark, near the canker.

Canadian Forest Service Publications

Nectria canker

Information on host(s)

Main host(s)

American beech, basswood, grey birch, largetooth aspen, red maple, sugar maple, trembling aspen, white birch, yellow birch

Photos
  • Nectria canker Branch killed by the canker
  • Nectria canker A Nectria canker caused by Nectria galligena, on a white birch.
  • Nectria canker Fruiting bodies of Nectria galligena, the causal agent of Nectria canker, on the margin of a canker on white birch.
  • Nectria canker Target canker
  • Nectria canker Callus swelling
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