''Helicobasidium purpureum'' is a

fungal A fungus ( : fungi 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 a kingdom, separately from th ...

plant pathogen Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomyc ...

which causes violet root rot in a number of susceptible plant

hosts 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 People *Jim Host (born 1937), American businessman *Michel Host ( ...

. It is synonymous with ''Helicobasidium brebissonii'' (Desm.) Donk. It is the

teleomorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an ase ...

of ''Tuberculina persicina'' which is its mycoparasitic

anamorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an ase ...

Varieties

There are three varieties: *''Helicobasidium purpureum var. barlae'' Bres. 1909 *''Helicobasidium purpureum var. orientale''Pat. 1920 *''Helicobasidium purpureum var. purpureum''(Tul.) Pat. 1885

Distribution

''Helicobasidium purpureum'' has a

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext ...

and is found in all regions in which its host plants grow.

Host plants

In the United Kingdom, colonies of ''Helicobasidium purpureum'' have been found on the living stems of

dog's mercury ''Mercurialis perennis'', commonly known as dog's mercury, is a poisonous woodland plant found in much of Europe as well as in Algeria, Iran, Turkey, and the Caucasus, but almost absent from Ireland, Orkney and Shetland.stinging nettle ''Urtica dioica'', often known as common nettle, burn nettle, stinging nettle (although not all plants of this species sting) or nettle leaf, or just a nettle or stinger, is a herbaceous perennial flowering plant in the family Urticaceae. Or ...

(''Urtica dioica''). The fungus is also associated as a

saprobe Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi (f ...

with decaying wood and stumps of broad leaf trees. Its

rhizoctonia ''Rhizoctonia'' is a genus of fungi in the order Cantharellales. Species form thin, effused, corticioid basidiocarps (fruit bodies), but are most frequently found in their sterile, anamorphic state. ''Rhizoctonia'' species are saprotrophic, but ...

infects the roots of

carrot The carrot ('' Daucus carota'' subsp. ''sativus'') is a root vegetable, typically orange in color, though purple, black, red, white, and yellow cultivars exist, all of which are domesticated forms of the wild carrot, ''Daucus carota'', nat ...

(''Daucus carota''),

parsnip The parsnip (''Pastinaca sativa'') is a root vegetable closely related to carrot and parsley, all belonging to the flowering plant family Apiaceae. It is a biennial plant usually grown as an annual. Its long taproot has cream-colored skin an ...

(''Pastinaca sativa''), swede (''Brassica napus ssp rapifera''),

turnip The turnip or white turnip (''Brassica rapa'' subsp. ''rapa'') is a root vegetable commonly grown in temperate climates worldwide for its white, fleshy taproot. The word ''turnip'' is a compound of ''turn'' as in turned/rounded on a lathe and ' ...

(''Brassica rapa''),

celery Celery (''Apium graveolens'') is a marshland plant in the family Apiaceae that has been cultivated as a vegetable since antiquity. Celery has a long fibrous stalk tapering into leaves. Depending on location and cultivar, either its stalks, lea ...

(''Apium graveolens''),

asparagus Asparagus, or garden asparagus, folk name sparrow grass, scientific name ''Asparagus officinalis'', is a perennial flowering plant species in the genus ''Asparagus''. Its young shoots are used as a spring vegetable. It was once classified in ...

(''Asparagus officinalis''),

beetroot The beetroot is the taproot portion of a beet plant, usually known in North America as beets while the vegetable is referred to as beetroot in British English, and also known as the table beet, garden beet, red beet, dinner beet or golden beet ...

(''Beta vulgaris''),

potato The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae. Wild potato species can be found from the southern Unit ...

(''Solanum tuberosum'') and

sea kale ''Crambe maritima'', common name sea kale, seakale or crambe, is a species of halophytic (salt-tolerant) flowering plant in the genus ''Crambe'' of the family Brassicaceae. It grows wild along the coasts of mainland Europe and the British Isl ...

(''Crambe maritima''). Wild plants on which it has been found felting the roots with purple or brown

mycelium Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrate (biology), substrates. A typical single ...

include

chickweed ''Stellaria media'', chickweed, is an annual and perennial flowering plant in the family Caryophyllaceae.Fernald, M. L. 1950. “Gray's Manual of Botany”. Eight Edition. American Book Company, New York, NY. 1632 pp. It is native to Euras ...

(''Stellaria'') spp., sow thistles (''Sonchus'') spp., nettles (''Urtica'') spp.,

shepherd's purse ''Capsella bursa-pastoris'', known as shepherd's purse because of its triangular flat fruits, which are purse-like, is a small annual and ruderal flowering plant in the mustard family (Brassicaceae). It is native to eastern Europe and Asia minor, ...

(''Capsella bursa-pastoris'') and

yarrow ''Achillea millefolium'', commonly known as yarrow () or common yarrow, is a flowering plant in the family Asteraceae. Other common names include old man's pepper, devil's nettle, sanguinary, milfoil, soldier's woundwort, and thousand seal. The ...

(''Achillea millefolium'').

Symptoms

In susceptible crops, any parts below the ground are liable to infection. The mycelium of the fungus forms a matted, felt-like purple covering which grows over the surface of the root. Soil particles adhere to this and small, dark-coloured

sclerotia A sclerotium (; (), is a compact mass of hardened fungal mycelium containing food reserves. One role of sclerotia is to survive environmental extremes. In some higher fungi such as ergot, sclerotia become detached and remain dormant until favor ...

grow among 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 or ...

e. A dry rot occurs and secondary rots may move in. Mycelial threads, often merging into strands, grow through the soil and infect nearby plants. A pink or brown mat of mycelial threads may grow above the soil surface. In affected plants, the aerial parts may wilt and have discoloured, stunted foliage.

Control

Violet root rot chiefly occurs in waterlogged, acid soils. These conditions can be improved by choosing a well-drained location to grow root crops and liming the soil. Individual affected plants can be removed and destroyed. The mycelium and sclerotia remain infective for some time and the ground should not be used again for root crops for at least four years. In the interim, susceptible

weed A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...

s should not be allowed to grow.

References

{{DEFAULTSORT:Helicobasidium purpureum Fungal plant pathogens and diseases Vegetable diseases Teliomycotina Fungi described in 1885 Taxa named by Edmond Tulasne