Young trees: all needles turning yellow green, then red, finally brown. On the stem base below the bark white, thin fan-shaped mycelium, no strands. Old trees: stem base typically bottle-shaped, mostly sunken on one side, in cross section reddish rot, heart-and springwood; fruiting bodies on the stem base, sometimes covered by soil: flat, thin, but very tough, 5-40cm in size, tubes whitish, very fine pores, outside black to brown and bumpy; the disease can be mistaken for damage by honey fungus or other rot fungi.
Affected tree species
Alder; Ash; Cedar; Cherry; Common whitebeam; Douglas fir; Elm; European mountain ash; Fir; Hawthorne; Hazel; Hemlock; Juniper; Larch; Leyland cypress; Oak; Pine; Rhododendron; Spruce; Thuja;
Needle; Stem; Shoot/Twig/Branch; Root;
Conifers rich in resin (pines): quick decline of roots, infection mostly deadly, no primary rot; conifers poor in resin (spruces): quick decline only with young plants, otherwise only stem rot for a long time. In Austria primarily a wound parasite (stem wounds by forest management or by cattle grazing in the forest); also a special problem of afforestations on agricultural soils (antagonists missing)
Curative measures Curative measures nor possible; preventiv measures: avoidance of any wounds at the stem base and on main roots; in some countries antagonistic microfungi (mainly Phlebiopsis gigantea) are sprayed onto the stumps of freshly cut trees as a long-term control measure.
Pine with infection by Heterobasidion annosum: whit mycelium underneath the bark and young fruiting bodies at the stem base (left and right below)
Heterobasidion annosum: a problem in afforestations of Scots pine on soils which have been used for agriculture for a long time
Heterobasidion annosum: fruiting body at the stem base of Sitka spruce
Heterobasidion annosum: mycelium with spores of the asexual stage Spiniger on a wood disk of spruce