''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

s. As well as impacting large scale agriculture, ''Phytophthora'' is a nuisance to garden and indoor plant hobbyists as well as bonsai artists. The cell wall of ''Phytophthora'' is made up of cellulose. The genus was first described by Heinrich Anton de Bary in 1875. Approximately 170 species have been described, although 100–500 undiscovered ''Phytophthora'' species are estimated to exist.

Pathogenicity

''Phytophthora''

spp. In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexe ...

are mostly pathogens of

dicotyledon The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, t ...

s, and many are relatively host-specific parasites. '' Phytophthora cinnamomi'', though, infects thousands of species ranging from

club moss Lycopodiopsida is a class of vascular plants known as lycopods, lycophytes or other terms including the component lyco-. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching s ...

es,

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except t ...

cycad Cycads are seed plants that typically have a stout and woody (ligneous) trunk (botany), trunk with a crown (botany), crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants o ...

conifer 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 single ...

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...

es, lilies, to members of many dicotyledonous families. Many species of ''Phytophthora'' are

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

s of considerable economic importance. ''

Phytophthora infestans ''Phytophthora infestans'' is an oomycete or water mold, a fungus-like microorganism that causes the serious potato and tomato disease known as late blight or potato blight. Early blight, caused by ''Alternaria solani'', is also often called "pot ...

'' was the infective agent of the potato blight that caused the Great Famine of Ireland, and still remains the most destructive pathogen of

solanaceous The Solanaceae , or nightshades, are a family of flowering plants that ranges from annual and perennial herbs to vines, lianas, epiphytes, shrubs, and trees, and includes a number of agricultural crops, medicinal plants, spices, weeds, and orna ...

crops, including tomato and potato. The soya bean root and stem rot agent, ''

Phytophthora sojae ''Phytophthora sojae'' is an oomycete and a soil-borne plant pathogen that causes stem and root rot of soybean. This is a prevalent disease in most soybean growing regions, and a major cause of crop loss. In wet conditions the pathogen produces z ...

'', has also caused longstanding problems for the agricultural industry. In general, plant diseases caused by this genus are difficult to control chemically, thus the growth of resistant

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...

s is the main management strategy. Other important ''Phytophthora'' diseases are: * ''

Phytophthora agathidicida ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

''—causes collar-rot on

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

kauri ('' Agathis australis''), New Zealand's most voluminous tree, an otherwise successful survivor of the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

* '' Phytophthora cactorum''—causes

rhododendron root rot ''Phytophthora cactorum'' is a fungal-like plant pathogen belonging to the Oomycota phylum. It is the causal agent of root rot on rhododendron and many other species, as well as leather rot of strawberries. . Hosts, symptoms, and diagnosis ''Phy ...

affecting rhododendrons, azaleas, and orchids, and causes bleeding canker in hardwood trees * ''

Phytophthora capsici ''Phytophthora capsici'' is an oomycete plant pathogen that causes blight and fruit rot of peppers and other important commercial crops. It was first described by L. Leonian at the New Mexico State University Agricultural Experiment Station in ...

''—infects Cucurbitaceae fruits, such as

cucumber Cucumber (''Cucumis sativus'') is a widely-cultivated Vine#Horticultural climbing plants, creeping vine plant in the Cucurbitaceae family that bears usually cylindrical Fruit, fruits, which are used as culinary vegetables.

s and squash * '' Phytophthora cinnamomi''—causes cinnamon root rot affecting forest and fruit trees, and woody ornamentals including

arborvitae ''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''. ...

azalea Azaleas are flowering shrubs in the genus ''Rhododendron'', particularly the former sections ''Tsutsusi'' (evergreen) and '' Pentanthera'' (deciduous). Azaleas bloom in the spring (April and May in the temperate Northern Hemisphere, and Octob ...

Chamaecyparis ''Chamaecyparis'', common names cypress or false cypress (to distinguish it from related cypresses), is a genus of conifers in the cypress family Cupressaceae, native to eastern Asia (Japan and Taiwan) and to the western and eastern margins of th ...

dogwood ''Cornus'' is a genus of about 30–60 species of woody plants in the family Cornaceae, commonly known as dogwoods, which can generally be distinguished by their blossoms, berries, and distinctive bark. Most are deciduous trees or shrub ...

forsythia ''Forsythia'' , is a genus of flowering plants in the olive family Oleaceae. There are about 11 species, mostly native to eastern Asia, but one native to southeastern Europe. ''Forsythia'' – also one of the plant's common names – is ...

, Fraser fir, hemlock, Japanese holly,

juniper Junipers are coniferous trees and shrubs in the genus ''Juniperus'' () of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere, from the Arcti ...

Pieris Pieris may refer to: Organisms * ''Pieris'' (plant), the andromeda or fetterbush, a plant genus in the family Ericaceae * ''Pieris'' (butterfly), the garden whites, a butterfly genus in the family Pieridae * ''Pieris'', a synonym of the genus ...

rhododendron ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nati ...

Taxus ''Taxus'' is a genus of coniferous trees or shrubs known as yews in the family Taxaceae. They are relatively slow-growing and can be very long-lived, and reach heights of , with trunk girth averaging . They have reddish bark, lanceolate, flat, ...

, white pine,

American chestnut The American chestnut (''Castanea dentata'') is a large, fast-growing deciduous tree of the beech family native to eastern North America. As is true of all species in genus Castanea, the American chestnut produces burred fruit with edible nuts. ...

and Australian woody plants, especially eucalypt and banksia. * '' Phytophthora citricola''—causes root rot and stem cankers in citrus trees * ''

Phytophthora fragariae ''Phytophthora fragariae'' is a fungus-like (oomycete) plant pathogen that causes red stele, otherwise known as Lanarkshire disease, in strawberries. Symptoms of red stele can include a red core in the roots, wilting of leaves, reduced floweri ...

''—causes red root rot affecting strawberries * ''

'' causes the serious disease known as potato (late) blight: responsible for the Great Famine of Ireland. * ''

Phytophthora kernoviae ''Phytophthora kernoviae'' is a plant pathogen that mainly infects European beech (''Fagus sylvatica'') and ''Rhododendron ponticum''. It was first identified in 2003 in Cornwall, UK when scientists were surveying for the presence of ''Phytoph ...

''—pathogen of

beech Beech (''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to temperate Europe, Asia, and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, ''Engleriana'' and ''Fagus''. The ''Engle ...

and rhododendron, also occurring on other trees and shrubs including

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

, and

holm oak Holm oak may refer to: * '' Quercus ilex'', tree native to South and Southeast Europe and parts of France * '' Quercus rotundifolia'', tree native to the Iberian Peninsula and Northwest Africa * ''Quercus agrifolia ''Quercus agrifolia'', the Cal ...

. First seen in Cornwall, UK, in 2003. * ''

Phytophthora lateralis ''Phytophthora lateralis'' is a soil-borne plant pathogen that causes cedar root disease in Lawson cypresses (''Chamaecyparis lawsoniana'') in Northern USA. This pathogen was first noted to cause disease in around 1920 on nursery stock near Seat ...

''—causes cedar root disease in Port Orford cedar trees * ''

Phytophthora megakarya ''Phytophthora megakarya'' is an oomycete plant pathogen that causes black pod disease in cocoa trees in west and central Africa. This pathogen can cause detrimental loss of yield in the economically important cocoa industry, worth approximate ...

''—one of the cocoa

black pod disease Black pod disease is a protozoal disease of Cocoa trees. This pathogen if left untreated can destroy all yields; annually the pathogen can cause a yield loss of up to 1/3 and up to 10% of total trees can be lost completely. With the value of the ...

species, is

invasive Invasive may refer to: *Invasive (medical) procedure *Invasive species *Invasive observation, especially in reference to surveillance *Invasively progressive spread of disease from one organ in the body to another, especially in reference to cancer ...

and probably responsible for the greatest

cocoa Cocoa may refer to: Chocolate * Chocolate * ''Theobroma cacao'', the cocoa tree * Cocoa bean, seed of ''Theobroma cacao'' * Chocolate liquor, or cocoa liquor, pure, liquid chocolate extracted from the cocoa bean, including both cocoa butter and ...

crop loss in Africa * ''

Phytophthora multivora ''Phytophthora multivora'' is a species of Oomycete, water moulds, identified as a plant pathogen implicated in dieback. It was first isolated in tuart forest of Southwest Australia in a study of the decline of tuart ''Eucalyptus gomphocephala'', ...

''—discovered in analysis of isolates with ''P. cinnamomi'' dieback infections of tuart forests of Southwest Australia, which were previously diagnosed as ''P. citricola''. The species was found occurring on many other taxa, so named ''multivora''. * ''

Phytophthora nicotianae ''Phytophthora nicotianae'' or black shank is an oomycete belonging to the order Peronosprales and family Peronosporaceae. Hosts and symptoms ''Phytophthora nicotianae'' has a broad host range comprising 255 genera from 90 families. Hosts inclu ...

''—infects

onion An onion (''Allium cepa'' L., from Latin ''cepa'' meaning "onion"), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus ''Allium''. The shallot is a botanical variety of the onion ...

s * ''

Phytophthora palmivora ''Phytophthora palmivora'' is an oomycete that causes bud-rot of palms, fruit-rot or kole-roga of coconut and areca nut. These are among the most serious diseases caused by fungi and moulds in South India. It occurs almost every year in Malna ...

''—causes fruit rot in

coconut The coconut tree (''Cocos nucifera'') is a member of the palm tree family ( Arecaceae) and the only living species of the genus ''Cocos''. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, the seed, or the ...

s and

betel nut The betel (''Piper betle'') is a vine of the family Piperaceae, which includes pepper and kava. The betel plant is native to Southeast Asia. It is an evergreen, dioecious perennial, with glossy heart-shaped leaves and white catkins. Betel plan ...

s * '' Phytophthora ramorum''—infects over 60 plant genera and over 100 host species; causes sudden oak death * ''

Phytophthora quercina ''Phytophthora quercina'' is a papillate homothallic soil-borne plant pathogen causing root rot of oak tree species in Europe. It is associated with necrotic fine roots. In culture, this species shows a uniform, dome-shaped and cottonwool-like ...

''—causes oak death * ''

''—causes

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 an ...

root rot Research beginning in the 1990s has placed some of the responsibility for European forest die-back on the activity of imported Asian ''Phytophthoras''. In 2019, scientists in Connecticut were conducting experiments testing various methods to grow healthier Fraser trees when they accidentally discovered a new species of ''Phytophthora'', which they called ''Phytophthora abietivora''. The fact that these scientists so readily discovered a new species further suggests that there could be many more species waiting to be discovered.

Species

The NCBI lists: *''

Phytophthora acerina ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora alni ''Phytophthora alni'' is an oomycete plant pathogen that causes lethal root and collar rot in alders. It is widespread across Europe and has recently been found in North America. This species is believed to have originated relatively recently. ...

'' *'' Phytophthora × alni'' *''

Phytophthora alticola ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora amaranthi ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora amnicola ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora amnicola × moyootj'' *''

Phytophthora andina ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora aquimorbida'' *''

Phytophthora arecae ''Phytophthora palmivora'' is an oomycete that causes bud-rot of palms, fruit-rot or kole-roga of coconut and areca nut. These are among the most serious diseases caused by fungi and moulds in South India. It occurs almost every year in Malna ...

'' *''

Phytophthora arenaria ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora cf. arenaria'' *'' Phytophthora aff. arenaria'' *'' Phytophthora asiatica'' *''

Phytophthora asparagi ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora aff. asparagi ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora attenuata ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora austrocedrae ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora balyanboodja ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora batemanensis ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora bilorbang'' *''

Phytophthora bisheria ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora bishii'' *''

Phytophthora boehmeriae ''Phytophthora boehmeriae'' is an oomycete plant pathogen that causes disease on a wide range of host plants, including root rot of Mexican yellow pine and brown rot of Citrus ''Citrus'' is a genus of flowering trees and shrubs in the ru ...

'' *'' Phytophthora boodjera'' *'' Phytophthora borealis'' *'' Phytophthora botryosa'' *'' Phytophthora cf. botryosa'' *'' Phytophthora aff. botryosa'' *''

Phytophthora brassicae ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora cactorum'' **''

Phytophthora cactorum var. applanata ''Phytophthora citricola'' is a plant pathogen. It was first described by Kaneyoshi (Kenkichi) Sawada in 1927 when it was isolated from orange trees in present-day Taiwan. It has since been found causing disease on a wide variety of plants. See ...

'' *'' Phytophthora cactorum × hedraiandra'' *''

Phytophthora cajani ''Phytophthora cajani'' is a species of water mould that infects pigeon pea The pigeon pea (''Cajanus cajan'') is a perennial legume from the family Fabaceae native to the Old World. The pigeon pea is widely cultivated in tropical and semitro ...

'' *''

Phytophthora cambivora ''Phytophthora'' × ''cambivora'' is a plant pathogen that causes ink disease in European chestnut trees (''Castanea sativa''). Ink disease, also caused by ''Phytophthora cinnamomi'', is thought to have been present in Europe since the 18th cent ...

'' *'' Phytophthora capensis'' *''

'' *'' Phytophthora aff. capsici'' *'' Phytophthora captiosa'' *''

Phytophthora castaneae ''Phytophthora katsurae'' is a plant pathogen. It was first isolated from chestnut (''Castanea'') trees in Japan.http://www.extento.hawaii.edu/Kbase/crop/Type/p_katsu.htm ''Phytophthora katsurae''. ''Crop Knowledge Master''. It has also been repo ...

'' *''

Phytophthora castanetorum ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora chlamydospora'' *'' Phytophthora chrysanthemi'' *'' Phytophthora cichorii'' *'' Phytophthora aff. cichorii'' *'' Phytophthora cinnamomi'' **'' Phytophthora cinnamomi var. cinnamomi'' **'' Phytophthora cinnamomi var. parvispora'' **''

Phytophthora cinnamomi var. robiniae ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora citricola'' *'' Phytophthora aff. citricola'' *''

Phytophthora citrophthora ''Phytophthora citrophthora'', also known as brown rot of citrus, is a soil borne oomycete that infects several economically important citrus crops. A diagnostic symptom of ''P. citrophthora'' is gummosis, wherein lesions around the base of the t ...

'' **'' Phytophthora citrophthora var. clementina'' *'' Phytophthora aff. citrophthora'' *'' Phytophthora clandestina'' *''

Phytophthora cocois ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora colocasiae Taro Leaf Blight (''Phytophthora colocasiae'') is a highly infectious plant disease that is characterized by the formation of large brown lesions on the leaves of infected taro plants.Nelson, S., Brooks, F., and Teves, G. July 2011. Taro leaf bli ...

'' *'' Phytophthora condilina'' *''

Phytophthora constricta ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora cooljarloo ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora crassamura ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora cryptogea ''Phytophthora cryptogea'' is a species of Oomycete, water mould in the family Pythiaceae. It is a plant pathology, plant pathogen that infects several species of cultivated plants, including over 40 species of cultivated flowers.Olson, H. A., et ...

'' *'' Phytophthora aff. cryptogea'' *''

Phytophthora cuyabensis ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora cyperi'' *'' Phytophthora dauci'' *'' Phytophthora aff. dauci'' *''

Phytophthora drechsleri ''Phytophthora drechsleri'' is a plant pathogen with many hosts. Affected plants See: * List of potato diseases * List of maize diseases * List of almond diseases * List of apricot diseases * List of beet diseases * List of caneberries disea ...

'' **'' Phytophthora drechsleri var. cajani'' *'' Phytophthora elongata'' *'' Phytophthora cf. elongata'' *''

Phytophthora erythroseptica ''Phytophthora erythroseptica''—also known as pink rot along with several other species of ''Phytophthora''—is a plant pathogen. It infects potatoes (''Solanum tuberosum'') causing their tubers to turn pink and damages leaves. It also ...

'' **'' Phytophthora erythroseptica var. pisi'' *'' Phytophthora aff. erythroseptica'' *''

Phytophthora estuarina ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora europaea'' *'' Phytophthora fallax'' *''

Phytophthora flexuosa ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora fluvialis ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora fluvialis × moyootj'' *''

Phytophthora foliorum ''Phytophthora'' (from Greek language, Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on cro ...

'' *''

Phytophthora formosa ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora formosana'' *''

'' *'' Phytophthora fragariaefolia'' *''

Phytophthora frigida ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora gallica'' *'' Phytophthora gemini'' *''

Phytophthora gibbosa ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora glovera ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora gonapodyides ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora gondwanensis'' *''

Phytophthora gregata ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora cf. gregata'' *''

Phytophthora hedraiandra ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora aff. hedraiandra ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora × heterohybrida'' *''

Phytophthora heveae ''Phytophthora'' (from Greek language, Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on cro ...

'' *''

Phytophthora hibernalis ''Phytophthora hibernalis'' is a plant pathogen infecting citrus ''Citrus'' is a genus of flowering plant, flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as O ...

'' *'' Phytophthora himalayensis'' *''

Phytophthora himalsilva ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora aff. himalsilva'' *''

Phytophthora humicola ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora aff. humicola'' *''

Phytophthora hydrogena ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora hydropathica'' *''

Phytophthora idaei ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora ilicis ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora × incrassata'' *''

'' *'' Phytophthora aff. infestans'' *'' Phytophthora inflata'' *'' Phytophthora insolita'' *'' Phytophthora cf. insolita'' *''

Phytophthora intercalaris ''Phytophthora'' (from Greek language, Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on cro ...

'' *''

Phytophthora intricata ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora inundata'' *''

Phytophthora ipomoeae ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora iranica ''Phytophthora iranica'' is a plant pathogen that infects the roots of Myrtle. It was discovered in a commercial nursery in Sardinia, Italy Sardinia ( ; it, Sardegna, label= Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardh ...

'' *''

Phytophthora irrigata ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora katsurae'' *''

Phytophthora kelmania ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

'' *'' Phytophthora kwongonina'' *'' Phytophthora lactucae'' *''

Phytophthora lacustris ''Phytophthora lacustris'' is an oomycete plant pathogen. Hosts and symptoms ''P. lacustris'' has a wide host range as well as a very wide geographical range, being found worldwide.Nechwatal, J., et al. "The Morphology, Behaviour and Molecular ...

'' *'' Phytophthora lacustris × riparia'' *''

'' *''

Phytophthora lilii ''Phytophthora'' (from Greek language, Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on cro ...

'' *'' Phytophthora litchii'' *''

Phytophthora litoralis ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora litoralis × moyootj'' *''

Phytophthora macilentosa ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora macrochlamydospora'' *''

Phytophthora meadii ''Phytophthora'' (from Greek language, Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on cro ...

'' *'' Phytophthora aff. meadii'' *'' Phytophthora medicaginis'' *'' Phytophthora medicaginis × cryptogea'' *''

'' *''

Phytophthora megasperma ''Phytophthora megasperma'' is a species of water mould in the family Peronosporaceae. It is well known as a plant pathogen with many hosts. It often causes a plant disease called root rot.Phytophthora melonis'' *'' Phytophthora mengei'' *'' Phytophthora mexicana'' *''

Phytophthora cf. mexicana ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora mirabilis ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora mississippiae ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, ...

'' *'' Phytophthora morindae'' *'' Phytophthora moyootj'' *'' Phytophthora moyootj × fluvialis'' *'' Phytophthora moyootj × litoralis'' *'' Phytophthora moyootj × thermophila'' *'' Phytophthora × multiformis'' *''

Phytophthora multivesiculata ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora nagaii ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora nemorosa'' *''

'' **'' Phytophthora nicotianae var. parasitica'' *'' Phytophthora nicotianae × cactorum'' *''

Phytophthora niederhauserii ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora cf. niederhauserii ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora obscura'' *''

Phytophthora occultans ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora oleae'' *''

Phytophthora ornamentata ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora pachypleura'' *''

'' **'' Phytophthora palmivora var. palmivora'' *''

Phytophthora parasitica ''Phytophthora nicotianae'' or black shank is an oomycete belonging to the order Peronosprales and family Peronosporaceae. Hosts and symptoms ''Phytophthora nicotianae'' has a broad host range comprising 255 genera from 90 families. Hosts inclu ...

'' **'' Phytophthora parasitica var. nicotianae'' **''

Phytophthora parasitica var. piperina ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora parsiana'' *'' Phytophthora aff. parsiana'' *'' Phytophthora parvispora'' *'' Phytophthora × pelgrandis'' *''

Phytophthora phaseoli ''Phytophthora phaseoli'' is a plant pathogen which infects lima bean A lima bean (''Phaseolus lunatus''), also commonly known as the butter bean, sieva bean, double bean, Madagascar bean, or wax bean is a legume grown for its edible seeds or ...

'' *''

Phytophthora pini ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora pinifolia ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora pisi ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora pistaciae ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora plurivora'' *'' Phytophthora pluvialis'' *'' Phytophthora polonica'' *''

Phytophthora porri ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora primulae'' *'' Phytophthora aff. primulae'' *''

Phytophthora pseudocryptogea ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora pseudolactucae'' *''

Phytophthora pseudorosacearum ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora pseudosyringae ''Phytophthora pseudosyringae'' is a semi-papillate homothallic soil-borne plant pathogen causing root and collar rot of broadleaf tree species in Europe. It is associated with necrotic fine roots and stem necroses of ''Fagus sylvatica'' and ' ...

'' *''

Phytophthora pseudotsugae ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora aff. pseudotsugae ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora psychrophila'' *'' Phytophthora quercetorum'' *''

'' *''

Phytophthora quininea ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora ramorum'' *'' Phytophthora rhizophorae'' *'' Phytophthora richardiae'' *''

Phytophthora riparia ''Phytophthora'' (from Greek language, Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on cro ...

'' *''

Phytophthora rosacearum ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora aff. rosacearum'' *'' Phytophthora rubi'' *''

Phytophthora sansomea ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, ...

'' *'' Phytophthora sansomeana'' *'' Phytophthora aff. sansomeana'' *''

Phytophthora × serendipita ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora sinensis ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora siskiyouensis ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora stricta ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora sulawesiensis'' *'' Phytophthora syringae'' *''

Phytophthora tabaci ''Phytophthora nicotianae'' or black shank is an oomycete belonging to the order Peronosprales and family Peronosporaceae. Hosts and symptoms ''Phytophthora nicotianae'' has a broad host range comprising 255 genera from 90 families. Hosts incl ...

'' *''

Phytophthora tentaculata ''Phytophthora tentaculata'' is a plant pathogen that causes root and stalk rot. It was first isolated in 1993 in a nursery in Germany infecting ''Chrysanthemum'', ''Verbena'', and ''Delphinium ajacis''. It has since been found infecting a ''Ver ...

'' *''

Phytophthora terminalis ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *''

Phytophthora thermophila ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora thermophila × amnicola'' *'' Phytophthora thermophila × moyootj'' *''

Phytophthora trifolii ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora tropicalis'' *'' Phytophthora cf. tropicalis'' *'' Phytophthora tubulina'' *'' Phytophthora tyrrhenica'' *'' Phytophthora uliginosa'' *'' Phytophthora undulata'' *''

Phytophthora uniformis ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora vignae'' **'' Phytophthora vignae f. sp. adzukicola'' *''

Phytophthora virginiana ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as ...

'' *'' Phytophthora vulcanica''

Resemblance to fungi

''Phytophthora'' is sometimes referred to as a

fungus 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 ...

-like organism, but it is classified under a different

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

altogether: SAR supergroup (Harosa) (also under

Stramenopila Stramenopile is a clade of organisms distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached to flagella, in some they are attached to other areas of the cellular surface, and in some they have b ...

and previously under Chromista). This is a good example of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

: ''Phytophthora'' is morphologically very similar to true fungi yet its evolutionary history is completely distinct. In contrast to fungi, SAR supergroup is more closely related to plants than to animals. Whereas fungal cell walls are made primarily of

chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

, ''Phytophthora'' cell walls are constructed mostly of

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...

. Ploidy levels are different between these two groups; ''Phytophthora'' species have

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

(paired) chromosomes in the vegetative (growing, nonreproductive) stage of life, whereas fungi are almost always

haploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

in this stage. Biochemical pathways also differ, notably the highly conserved

lysine Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. It contains an α-amino group (which is in the protonated form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −C ...

synthesis path.

Biology

''Phytophthora'' species may reproduce sexually or asexually. In many species, sexual structures have never been observed, or have only been observed in laboratory matings. In homothallic species, sexual structures occur in single culture. Heterothallic species have mating strains, designated as A1 and A2. When mated, antheridia introduce gametes into

oogonia An oogonium (plural oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes. In the mammalian fetus Oogonia are formed in larg ...

, either by the oogonium passing through the antheridium (amphigyny) or by the antheridium attaching to the proximal (lower) half of the oogonium (paragyny), and the union producing oospores. Like animals, but not like most true fungi, meiosis is gametic, and somatic nuclei are diploid. Asexual (mitotic) spore types are chlamydospores, and

sporangia A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cy ...

which produce

zoospore A zoospore is a motile asexual spore that uses a flagellum for locomotion. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Diversity Flagella types Zoospores may possess one or mo ...

s. Chlamydospores are usually spherical and pigmented, and may have a thickened cell wall to aid in their role as a survival structure. Sporangia may be retained by the subtending hyphae (noncaducous) or be shed readily by wind or water tension (caducous) acting as dispersal structures. Also, sporangia may release zoospores, which have two unlike

flagella A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...

which they use to swim towards a host plant. Zoospores (and zoospores of '' Pythium'', also in the Peronosporales) recognize not only hosts but particular locations on hosts. ''Phytophthora'' zoospores recognize and attach to specific root surface regions. This is a high degree of specificity at an early stage of cell development.

References

External links

* [https://web.archive.org/web/20070506074931/http://www.ladybug.uconn.edu/factsheets/tp_05_phytophthora.html Abbey, Tim (2005) "Phytophthora Dieback and Root Rot" College of Agriculture and Natural Resources, University of Connecticut]
"''Phytophthora'' Canker – Identification, Biology and Management"
Bartlett Tree Experts Online Resource Library
"''Phytophthora'' Root Rot – Identification, Biology and Management"
Bartlett Tree Experts Online Resource Library
Dieback Working Group
– Western Australia {{Taxonbar, from=Q311294 Water mould plant pathogens and diseases Water mould genera

Pathogenicity

Species

Resemblance to fungi

Biology

References

Further reading

External links