Silver leaf disease
Damage, symptoms and biology
The annual fruiting body forms a circular crust, sometimes with multiple, semicircular caps. The fruiting body is greyish with purple to purplish brown spore-producing areas.
The economic impact of the disease is greater on ornamental and orchard trees than on trees in a forestry setting. Chondrostereum purpureum is largely a saprophyte but can be a weak parasite on living hardwoods. Toxins produced by the fungus affect leaves, and on some hosts kill branches or entire trees. This fungus is currently being considered as a candidate for use as a biocontrol agent for hardwood stump sprouts under power lines.
Other related fungi in the Stereaceae such as Amylostereum, Stereum, Columnocystis or Peniophora could be confused with old fruiting bodies of C. purpureum.
Canadian Forest Service Publications
Information on host(s)
Apples, balsam poplar, beeches, black cottonwood, black-gum, Blue-beech, dogwoods, hackberry, hickory, hophornbeam, horsechestnuts, lilac, london plane-tree, maple, mountain alder, mountain-ash, oaks, plum, red alder, serviceberries, trembling aspen, tulip-tree, white birch, willow