''Phytophthora megasperma'' is a species of

water mould Oomycota forms a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms, called oomycetes (). They are filamentous and heterotrophic, and can reproduce both sexually and asexually. Sexual reproduction of an oospore is the r ...

in the family

Peronosporaceae Peronosporaceae are a family of water moulds that contains 21 genera, comprising more than 600 species. Most of them are called downy mildews. Peronosporaceae are obligate biotrophic plant pathogens. They parasitise their host plants as an ...

. It is well known as a plant pathogen with many hosts. It often causes a plant disease called root rot.''Phytophthora megasperma''.
Plantwise Knowledge Bank.

Taxonomy

This is a poorly defined species which is generally called a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

. Its name applies to water moulds of many forms, functions, and host preferences, many of which are actually different species which have not yet been separated and described.Wilcox, W. F. and S. M. Mircetich. (1987)
Lack of host specificity among isolates of ''Phytophthora megasperma''.
''Phytopathology'' 77(8) 1132-37.Hansen, E. M., et al. (2009)
''Phytophthora rosacearum'' and ''P. sansomeana'', new species segregated from the ''Phytophthora megasperma'' “complex”.
''Mycologia'' 101(1) 129-35. Some species previously treated as part of the complex include '' Phytophthora rosacearum'', '' P. sansomeana'', '' P. sojae'', '' P. medicaginis'', and '' P. trifolii''. A

form Form is the shape, visual appearance, or configuration of an object. In a wider sense, the form is the way something happens. Form also refers to: *Form (document), a document (printed or electronic) with spaces in which to write or enter data ...

of ''P. megasperma'' is suspected to be a separate species when it is recognized to have host specificity, when it is found attacking just one host plant; alfalfa in the case of ''P. medicaginis'', for example.

Host species

Water moulds in the ''P. megasperma'' complex can be found on a multitude of host plants, including many agricultural crops. It has been noted on

soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu a ...

kiwifruit Kiwifruit (often shortened to kiwi in North American, British and continental European English) or Chinese gooseberry is the edible berry of several species of woody vines in the genus '' Actinidia''. The most common cultivar group of kiwi ...

(''Actinidia deliciosa''),

horse chestnut The genus ''Aesculus'' ( or ), with species called buckeye and horse chestnut, comprises 13–19 species of flowering plants in the family Sapindaceae. They are trees and shrubs native to the temperate Northern Hemisphere, with six species n ...

(''Aesculus hippocastanum''),

hollyhock ''Alcea'' is a genus of over 80 species of flowering plants in the mallow family Malvaceae, commonly known as the hollyhocks. They are native to Asia and Europe. The single species of hollyhock from the Americas, the streambank wild hollyhock, ...

(''Alcea rosea''),

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''), ''

Brassica oleracea ''Brassica oleracea'' is a plant species from family Brassicaceae that includes many common cultivars used as vegetables, such as cabbage, broccoli, cauliflower, kale, Brussels sprouts, collard greens, Savoy cabbage, kohlrabi, and gai lan. ...

'', crops such as cabbage, cauliflower,

safflower Safflower (''Carthamus tinctorius'') is a highly branched, herbaceous, thistle-like annual plant in the family Asteraceae. It is commercially cultivated for vegetable oil extracted from the seeds and was used by the early Spanish colonies along ...

(''Carthamus tinctorius''),

Port Orford cedar ''Chamaecyparis lawsoniana'', known as Port Orford cedar or Lawson cypress, is a species of conifer in the genus '' Chamaecyparis'', family Cupressaceae. It is native to Oregon and northwestern California, and grows from sea level up to in th ...

(''Chamaecyparis lawsoniana''), chickpea (''Cicer arietinum''), carrot (''Daucus carota''),

carnation ''Dianthus caryophyllus'' (), commonly known as the carnation or clove pink, is a species of ''Dianthus''. It is likely native to the Mediterranean region but its exact range is unknown due to extensive cultivation for the last 2,000 years.Med ...

(''Dianthus caryophyllus''),

eucalyptus ''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as e ...

(''Eucalyptus'' spp.),

walnut A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, '' Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true ...

(''Juglans regia''),

apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ' ...

(''Malus domestica''),

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts ...

s (''Pinus'' spp.),

stone fruit In botany, a drupe (or stone fruit) is an indehiscent fruit in which an outer fleshy part ( exocarp, or skin, and mesocarp, or flesh) surrounds a single shell (the ''pit'', ''stone'', or ''pyrena'') of hardened endocarp with a seed (''kernel' ...

such as apricot, cherry, plum, and

peach The peach (''Prunus persica'') is a deciduous tree first domesticated and cultivated in Zhejiang province of Eastern China. It bears edible juicy fruits with various characteristics, most called peaches and others (the glossy-skinned, non-f ...

, Douglas fir (''Pseudotsuga menziesii''), sugarcane (''Saccharum officinarum''), and

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'').

References

External links

''Phytophthora megasperma''.
Index Fungorum. megasperma Water mould plant pathogens and diseases Soybean diseases Potato diseases {{plant-disease-stub