Silverleaf Fungus

It is a pathogen of various, mostly deciduous trees including species of Acer, Aesculus, Alnus, Betula, Crataegus, Fagus, Larix, Malus, Ostrya, Picea, Populus, Prunus, Salix, and Sorbus. After starting as just a crust on the wood, the fruiting structure develops undulating intergrowing brackets up to about 3 cm broad, which have a tough rubbery texture. The edges and fertile lower surfaces show a fairly vivid violet colour while the fungus is growing, and the upper surfaces have a grey aspect (sometimes with zonation and usually a lighter edge) and are covered with whitish hairs. After a week or two the fructification dries out, becomes brittle, and turns a drab brown or beige. Infected wood can be recognized because it is stained a darker tint. The spores are rounded cylinders approximately 5–8 μm x 3–4 μm in size. The hyphal structure is monomitic with clamp connections. It is often found on old stumps and dead wood, but can also be a serious parasite of living trees. As well as plum trees it attacks many other broad-leafed species (other Prunus, apple, pear, willow, poplar, maple, hornbeam, plane, oak, elm, lilac, and many others). Occasionally it also infects conifers (e.g. fir, spruce, and Thuja). Geographically it is roughly just as widespread as its hosts; it is common in woods, orchards and tree plantations in temperate climates.

Similar species. …