Death of branches, crown dieback; needle- or leaf discoloration, reddening of needles; on spruce and Douglas fir: yellowing of the youngest needles, later on reddish discoloration of the older needles, while the youngest stay yellow for a while; by contrast, Heterobasidion annosum - root rot results in simultaneous discoloration of all needles; on the stem: resin flow, sapflow, cracks; white mycelial fans between dead bark and wood, black, 1 to several mm thick fungal strands (rhizomorphs); rarely honey yellow to brown fruiting bodies close to the stem base; white rot
Affected tree species
Alder; All tree species; Apple; Ash; Beech; Birch; Bladdernut; Boxelder; Buckthorn; Cedar; Cherry; Common grape wine; Common medlar; Common whitebeam; Cotoneaster; Dogwood; Douglas fir; Edible chestnut; Elder; Elm; English ivy; European Hornbeam; European mountain ash; Ex-Robinia; False Cypress; Fir; Forsythia ; Framire; Giant sequoia; Ginkgo; Hackberry; Hawthorne; Hazel; Hemlock; Holly; Hophornbeam; Horse chestnut; Japanese Pagoda tree; Juniper; Larch; Leyland cypress; Lilac; Linden, Lime; Magnolia; Maple; Mulberry; Oak; Olive tree; Pear; Pine; Plane; Poplar; Privet; Redwood; Rhododendron; Rose; Serviceberry; Southern Catalpa; Spindle; Spruce; Thuja; Tree-of-heaven; Walnut; Wild service tree; Willow;
In Europe 11 species of differing pathogenicity; the more aggressive species belong to the most important and most common root rot callusing and cambium killing fungi of woody plants. Various weakening agents may trigger the infection of roots by Armillaria-mycelia; when the mycelium has reached the stem, the tree usually dies. Further information (in German): Gehölzkrankheiten in Wort und Bild (TUM Weihenstephan).
Curative measures Trees already infected can hardly be cured; as a preventive measure avoidance of all kinds of weakening; change of soil and removing of infected stumps should precede afforestation.
Honey fungus: rhizomorphs on a root of Tilia
Honey fungus: fruiting bodies
Honey fungus: resin flow on the stem
Honey fungus: early symptom on a young plant, older needles green, younger yellow
Honey fungus: mycelium between dead bark and wood
Honey fungus: fruiting bodies on a stump of poplar