Phytophthora lacustris

Name and publication

Phytophthora lacustris Brasier, Cacciola, Nechwatal, Jung & Bakonyi (2013)

Nechwatal J, Bakonyib J, Cacciola SO, Cooke DEL, Jung T, Nagy ZA, Vannini A, Vettraino AM, and Brasier CM. 2013. The morphology, behaviour, and molecular phylogeny of Phytophthora taxon Salixsoil and its redesignation as Phytophthora lacustris sp. nov. Plant Pathology 62: 355–369.

Corresponding author:


from Nechwatal et al. (2013)




(Lat. = from lakes, lacustrine) refers to the wet habitats preferred by this species


Type: UNITED KINGDOM: Bexley Heath, Kent, isolated from diseased root of Salix matsudana, 1972, C. M. Brasier & R. G. Strouts, P245 (dried culture on CA, herbarium of the Plant Protection Institute, Hungarian Academy of Sciences, Budapest, under accession number PPIHAS-P566)

Ex-type: culture P245 (UK Forestry Commission Culture Collection = IMI 389725: no results found) = P10337 at WPC

Sequences for ex-type in original manuscript: P245 = ITS AF266793, COX1 JF896561

NOTE: In previous studies P. lacustris is referred to as P. taxon Salixsoil.

Ex-type in other collections

P10337 (WOC/WPC) = CBS 133615, CPHST BL 69 (Abad)

Molecular identification

Voucher sequences for barcoding genes (ITS rDNA and COI) of the ex-type (see Molecular protocols page)

Phytophthora lacustris isolate P245 = ITS rDNA AF266793
Phytophthora lacustris isolate CPHST BL 69 ( = P10337) COI MH136916

Sequences for ex-type in other sources
Position in ITS phylogenetic tree

Clade 6

Morphological identification

adapted from Nechwatal et al. (2013)

Colonies and cardinal temperatures

Colony grown for 7 days on V8 agar, potato dextrose agar, and malt extract agar with chrysanthemum pattern. Minimum growth temperature 3°C, maximum 28–30°C, and optimum 37°C.

Conditions for growth and sporulation

Sporangia abundantly produced in nonsterile soil filtrate.

Asexual phase

Sporangia nonpapillate; persistent; ovoid or obpyriform (30–55 X 22–38 µm), showing internal, nested or extended proliferation, sometimes with external proliferation; originated in unbranched or with new sporangiophores emerging just below the mature sporangium. Hyphal swellings are rarely produced, subglobose or ellipsoid (12–18 X 8–10 µm), intercalary. Chlamydospores absent.

Sexual phase

Sterile. Sexual phase not observed, but isolates have induced gametangial formation in some A2 isolates of other species, e.g. P. cambivora (the P. lacustris isolate remained sterile, referred to as having a "silent A1 mating type").

Most typical characters

Phytophthora lacustris is characterized by the presence of sporangia with nested or extended proliferation and the production of intercalary hyphal swellings.

Additional specimen(s) evaluated

Phytophthora lacustris CPHST BL 69 ex-type = P10337 (World Phytophthora Collection)

Hosts and distribution

Notes: published online 2012; known as "Phytophthora taxon Salixsoil" before formal description

Distribution: widespread
Substrate: roots, bark; isolated from soil, water
Disease note: root rot, discoloration; weak bark pathogen
Host: Alnus spp. (Betulaceae), Salix sp. (Salicaceae), Prunus sp. (Rosaceae); associated with Phragmites australis (Poaceae).

Retrieved January 31, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

Fact sheet author

Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Beltsville Laboratory, United States of America