Phytophthora pseudosyringae

{{Short description|Species of single-celled organism}}

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| genus = Phytophthora

| species = pseudosyringae

| authority = T. Jung and T.I. Burgess, 2009

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Phytophthora pseudosyringae is a semi-papillate homothallic soil-borne plant pathogen causing root and collar rot of broadleaf tree species in Europe.{{cite journal|last1=Jung|first1=Thomas|last2=Nechwatal|first2=Jan|last3=Cooke|first3=David E.L.|last4=Hartmann|first4=Günther|last5=Blaschke|first5=Markus|last6=Oßwald|first6=Wolfgang F.|last7=Duncan|first7=James M.|last8=Delatour|first8=Claude|title=Phytophthora pseudosyringae sp. nov., a new species causing root and collar rot of deciduous tree species in Europe|journal=Mycological Research|volume=107|issue=7|year=2003|pages=772–789|issn=0953-7562|doi=10.1017/S0953756203008074|pmid=12967204}} It is associated with necrotic fine roots and stem necroses of Fagus sylvatica and Alnus glutinosa, and isolates are moderately aggressive to fine roots of oaks and beech (Nothofagus{{cite journal|last1=Scanu|first1=B.|last2=Jones|first2=B.|last3=Webber|first3=J.F.|title=A new disease of Nothofagus in Britain caused by Phytophthora pseudosyringae|journal=New Disease Reports|volume=25|year=2012|pages=27|issn=2044-0588|doi=10.5197/j.2044-0588.2012.025.027|doi-access=free}}), highly aggressive to holly leaves and apple fruits, and slightly pathogenic to alder bark.

It belongs to the class of oomycetes and is often described as a ‘fungal-like’ organism since they form a heterotrophic mycelium as the ‘true fungi’, but in contrast, their cell wall lacks chitin and is composed only of cellulose and glucans.{{citation needed|date=December 2023}}

Its name derives from Greek Phytophthora {{lang|el|φυτόν}} ({{Transliteration|el|phytón}}), “plant” and {{lang|el|φθορά}} ({{Transliteration|el|phthorá}}), “destruction”; “the plant-destroyer” and plurivora and from Latin ({{lang|la|pluri}} = many, -{{lang|la|vora}} = feeding).{{citation needed|date=December 2023}}