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Red butt rot and sap rot

Red butt rot and sap rot - Fruiting bodies of <em>C. volvatus</em>, some dissected longitudinally to show the spore-producing surface
  • Latin name: Cryptoporus volvatus (Peck) Shear
  • French name: Carie rouge du pied et carie de l'aubier
  • Division: Basidiomycota
  • Class: Aphyllophorales
  • Synonym(s): Polyporus volvotus Peck





Damage, symptoms and biology

The annual, semi-circular fruiting body has a membrane that covers the tubes. It resembles a pouch or small bag.

Grey sap rot develops rapidly in dead standing trees but is quite superficial, limited to the outer 1 to 2 cm of sapwood. As a result, little or no board-foot volume loss is associated with this decay.

Other information

Fruiting bodies usually develop the year after tree death occurs, and often form by the hundreds up the stem (Fig. c). On Douglas-fir, C. volvatus is often associated with old bark beetle galleries and can be used as an indicator of bark beetle kill. Sporophores of Cryptoporus volvatus could be confused with immature conks of other polypore fungi. The latter, however, are solid rather than "pouch-like." Insects have been shown to play a role in the dissemination of C. volvatus basidiospores.

Canadian Forest Service Publications

Red butt rot and sap rot

Information on host(s)

Main host(s)

Eastern white pine, red pine, Rocky Mountain Douglas-fir, scots pine

Secondary host(s)

Amabilis fir, black spruce, Engelmann spruce, grand fir, ponderosa pine, red spruce, shore pine, Sitka spruce, subalpine fir, western hemlock, western larch, western white pine, white spruce


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