''Chondrostereum purpureum'' is a

fungal A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as one of the tradit ...

plant pathogen which causes silver leaf disease of

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

s. It attacks most species of the rose family

Rosaceae Rosaceae (), the rose family, is a family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus '' Rosa''. The family includes herbs, shrubs, and trees. Most species are deciduous, but som ...

, particularly the genus ''

Prunus ''Prunus'' is a genus of flowering plant, flowering trees and shrubs from the family (biology), family Rosaceae. The genus includes plums, cherries, peaches, nectarines, apricots and almonds (collectively Drupe, stonefruit). The genus has a cosm ...

''. The disease is progressive and often fatal. The common name is taken from the progressive silvering of leaves on affected branches. It is spread by airborne

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s landing on freshly exposed sapwood. For this reason

cherries A cherry is the fruit of many plants of the genus ''Prunus'', and is a fleshy drupe (stone fruit). Commercial cherries are obtained from cultivars of several species, such as the sweet ''Prunus avium'' and the sour ''Prunus cerasus''. The name ...

and

plum A plum is a fruit of some species in Prunus subg. Prunus, ''Prunus'' subg. ''Prunus'.'' Dried plums are often called prunes, though in the United States they may be labeled as 'dried plums', especially during the 21st century. Plums are ...

s are pruned in summer, when spores are least likely to be present and when disease is visible. Silver leaf can also occur on poming fruits like

apples An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...

and

pear Pears are fruits produced and consumed around the world, growing on a tree and harvested in late summer into mid-autumn. The pear tree and shrub are a species of genus ''Pyrus'' , in the Family (biology), family Rosaceae, bearing the Pome, po ...

s; plums are especially vulnerable.

Taxonomy

In the past the name ''Stereum purpureum'' Pers. was widely used for this fungus, but according to modern taxonomy it is only distantly related to '' Stereum'', actually belonging to order

Agaricales The Agaricales are an order (biology), order of fungi in the division (mycology), division Basidiomycota. As originally conceived, the order contained all the agarics (gilled mushrooms), but subsequent research has shown that not all agarics are ...

whereas ''Stereum'' is in order ''

Russulales The Russulales are an order of the Agaricomycetes, (which include the agaric genera '' Russula'' and ''Lactarius'' and their polyporoid and corticioid relatives). According to the ''Dictionary of the Fungi'' (10th edition, 2008), the order con ...

''.

Description

It is a pathogen of various, mostly deciduous trees including species of '' Acer'', ''

Aesculus The genus ''Aesculus'' ( or ), with notable species including buckeye and horse chestnut, comprises 13–19 species of flowering plants in the family Sapindaceae. They are trees and shrubs native plant, native to the temperateness, temperat ...

'', ''

Alnus Alders are trees of the genus ''Alnus'' in the birch family Betulaceae. The genus includes about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species ext ...

'', ''

Betula A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains 3 ...

'', ''

Crataegus ''Crataegus'' (), commonly called hawthorn, quickthorn, thornapple, Voss, E. G. 1985. ''Michigan Flora: A guide to the identification and occurrence of the native and naturalized seed-plants of the state. Part II: Dicots (Saururaceae–Cornacea ...

'', ''

Fagus Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

'', ''

Larix Larches are deciduous conifers in the genus ''Larix'', of the family Pinaceae (subfamily Laricoideae). Growing from tall, they are native to the cooler regions of the northern hemisphere, where they are found in lowland forests in the high la ...

'', ''

Malus ''Malus'' ( or ) is a genus of about 32–57 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple, crab apples (sometimes known in North America as crabapples) and wild apples. The genus i ...

'', ''

Ostrya ''Ostrya'' is a genus of eight to 10 small deciduous trees belonging to the birch family Betulaceae. Common names include hop-hornbeam and hophornbeam. It may also be called ironwood, a name shared with a number of other plants. The genus is na ...

'', ''

Picea A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Northern hemisphere. ''Picea'' is the sole genus ...

'', ''

Populus ''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood. The we ...

'', ''

Salix Willows, also called sallows and osiers, of the genus ''Salix'', comprise around 350 species (plus numerous hybrids) of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions. Most species are known ...

'', and ''

Sorbus ''Sorbus'' is a genus of over 100 species of trees and shrubs in the rose family, Rosaceae. Species of ''Sorbus'' ('' s.str.'') are commonly known as rowan or mountain-ash. The genus used to include species commonly known as whitebeam, cheque ...

''. 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 The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

x 3–4 μm in size. The

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

l structure is

monomitic A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

with

clamp connection A clamp connection is a hook-like structure formed by growing hyphal cells of certain fungi. It is a characteristic feature of basidiomycete fungi. It is created to ensure that each cell, or segment of hypha separated by septa (cross walls), rece ...

s. It is often found on old stumps and dead wood, but can also be a serious

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

of living trees. As well as plum trees it attacks many other broad-leafed species (other ''

'',

apple An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...

willow Willows, also called sallows and osiers, of the genus ''Salix'', comprise around 350 species (plus numerous hybrids) of typically deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions. Most species are known ...

, poplar,

maple ''Acer'' is a genus of trees and shrubs commonly known as maples. The genus is placed in the soapberry family Sapindaceae.Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 nd more or less continuously updated si ...

hornbeam Hornbeams are hardwood trees in the plant genus ''Carpinus'' in the family Betulaceae. Its species occur across much of the temperateness, temperate regions of the Northern Hemisphere. Common names The common English name ''hornbeam'' derives ...

, plane,

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

elm Elms are deciduous and semi-deciduous trees comprising the genus ''Ulmus'' in the family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical- montane regions of North America and Eurasia, ...

lilac ''Syringa'' is a genus of 12 currently recognized species of flowering woody plants in the olive family or Oleaceae called lilacs. These lilacs are native to woodland and scrub from southeastern Europe to eastern Asia, and widely and commonly ...

, and many others).Se
Entry "Silver Leaf Disease"
of Natural Resources Canada (NRCan). Occasionally it also infects conifers (e.g.

fir Firs are evergreen coniferous trees belonging to the genus ''Abies'' () in the family Pinaceae. There are approximately 48–65 extant species, found on mountains throughout much of North and Central America, Eurasia, and North Africa. The genu ...

spruce A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...

, and ''

Thuja ''Thuja'' ( ) is a genus of coniferous tree or shrub in the Cupressaceae (cypress family). There are five species in the genus, two native to North America and three native to eastern Asia. The genus is monophyletic and sister to ''Thujopsis''. M ...

''). Geographically it is roughly just as widespread as its hosts; it is common in woods, orchards and tree plantations in temperate climates.

Similar species

'' Amylostereum areolatum'' is considered to be similar, and usually has moss covering its cap. '' Phlebiopsis crassa'' does not form caps, while members of '' Trichaptum'' form a continuous surface covered by teeth or pores.

As a human pathogen

A single case report confirmed human

infection An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

with ''Chondrostereum purpureum'' in a non

immunocompromised Immunodeficiency, also known as immunocompromise, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that affe ...

man who had been working with infected plant material. It was resolved by treating him with

antifungal medication An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as cry ...

, but indicates potential for a broader

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County * Host Island, in the Wilhelm Archipelago, Antarctica People * ...

range for plant fungus than previously believed.

Mycoherbicide

''Chondrostereum purpureum'' is commercially available as a method of combatting forest 'weed trees' such as

aspen Aspen is a common name for certain tree species in the Populus sect. Populus, of the ''Populus'' (poplar) genus. Species These species are called aspens: * ''Populus adenopoda'' – Chinese aspen (China, south of ''P. tremula'') * ''Populus da ...

beech Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

, birches,

pin cherry ''Prunus pensylvanica'', also known as bird cherry, fire cherry, pin cherry, and red cherry, is a North American cherry species in the genus ''Prunus''. Description ''Prunus pensylvanica'' grows as a shrub or small tree, usually with a straig ...

, poplars, and other species.Canadian patent 2451038
/ref> The fungus is applied directly to the weed trees in a nutrient paste which can be stored and handled conveniently. The first regulatory approval was granted in 2001 to Myco-Forestis Corporation and targeted species "including birch, pin-cherry, poplar/aspen, red maple, sugar maple, and speckled alder in the Boreal and Mixed forest regions of Canada, east of the Rocky Mountains". It had not been reported as of 2001 to cause any diseases in

coniferous Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

tree species Compatibility of the Open Government Licence - Canada with Wikimedia projects but apparently does. According to a 2007 regulatory decision of the Canadian

Pest Management Regulatory Agency The Pest Management Regulatory Agency (PMRA) is the Canadian government agency responsible for the regulation of pest control products in Canada under the federal authority of the '' Pest Control Products Act'' and Regulations. The agency is a bra ...

, the use of this control method in paste form on

Sitka spruce ''Picea sitchensis'', the Sitka spruce, is a large, coniferous, evergreen tree growing to just over tall, with a trunk diameter at breast height that can exceed 5 m (16 ft). It is by far the largest species of spruce and the fifth- ...

and

red alder ''Alnus rubra'', the red alder, is a deciduous broadleaf tree native to western North America (Alaska, Yukon, British Columbia, Washington, Oregon, California, Idaho and Montana). Description ''Alnus rubra'' is the largest species of alder in ...

will only have a limited impact on non-target trees since the fungal spores are ubiquitous anyway and healthy trees are resistant to attack.

References

External links

Royal Horticultural Society advice on the treatment of infected trees.
{{DEFAULTSORT:Chondrostereum Purpureum Fungal tree pathogens and diseases Parasitic fungi Mycoherbicides Fungi of Europe Cyphellaceae Fungi described in 1794 Taxa named by Christiaan Hendrik Persoon Fungus species

Taxonomy

Description

Similar species

As a human pathogen

Mycoherbicide

References

Further reading

External links