Phytophthora syringae (to be redescribed 2022)

Name and publication

Phytophthora syringae (Kleb.) Kleb. (1905)

Klebahn H. 1909. Krankheiten des Flieders, pp. 75. Figs. 45. Berlin Gebruder Borntraeger. (Phytophthora syringae)



MB 194524


Phloeophthora syringae Kleb., Zentbl. Bakt. ParasitKde: 335 (1905) [MB146927]

Nozemia syringae (Kleb.) Pethybr., Scientific Proceedings of the Royal Dublin Society 13 (1913) [MB416474]


from Klebahn (1909)

Type: GERMANY collected from Syringae vulgaris

Ex-type: LOST

Well-authenticated specimens selected by Gloria Abad: 
Selected specimen #1: CPHST BL 57G = P10330 from GERMANY, rhododendron

Selected specimen in other collections

P10330 (WPC) = CBS 110161, CPHST BL 57G (Abad), BBA 70008

Molecular identification

Voucher sequences for barcoding genes (ITS rDNA and COI) of selected specimens (see Molecular protocols page)

Phytophthora syringae isolate CPHST BL 57G (= P10330 WPC) = ITS rDNA MG865590, COI MH136982

Sequences for selected specimen in other sources
Position in ITS phylogenetic tree

Clade 8d

Genome sequence

Phytophthora syringae strain ex-neotype BL57G. Accession genome USDA_Psyr_BL57G_1.0 reference, BioProject PRJNA605765, USDA-APHIS-PPQ-S&T (2020), Srivastava et al 2022

Morphological identification

Colonies and cardinal temperatures

Colony on CMA with no special pattern, on PDA and V-8 with chrysanthemum/rosette pattern. The minimum temperature for growth is 5°C, the optimum is 18–20°C, and the maximum is 23–25°C.

Conditions for growth and sporulation

Oogonia form abundantly in culture and host tissues.

Asexual phase

Sporangia semipapillate; persistent; broad ovoid, ellipsoid, obpyriform, or distorted shapes (20–65 µm length x 18–40 µm width) sometimes with tapered base; originated in close simple sympodial sporangiophores with intercalary swellings. Hyphal swellings often catenulated, and spherical or irregular shape. Chlamydospores absent.

Sexual phase

Homothallic. Oogonium smooth-walled, globose (25–47 µm diam.), sometimes with tapered base; antheridia spherical, ovoid or club-shaped and are predominately paragynous and rarely amphigynous, sometimes with digitate projections; and oospores plerotic, aplerotic, or slightly aplerotic (20–39 µm diam.). 

Specimen(s) evaluated

Phytophthora syringae CPHST BL 57G = P10330 (World Phytophthora Collection)

Hosts and distribution

Distribution: Africa (Morocco, South, Africa), Australia, Asia (Korea) Europe (Italy), North America (Canada, USA), South America (Argentina, Brazil, Chile)
Substrate: roots, shoots, twigs, trunks, leaves, fruits
Disease note: twig blight, fruit rot, root rot, gummosis of citrus, stem canker, wilt, crown rot, collar rot; downy mildew, leaf spot, and shoot dieback of lilac
Host: 29 genera in 14 families, including Syringa vulgaris (Oleaceae) and Rosaceae

Retrieved February 01, 2018 fromU.S. National Fungus Collections Nomenclature Database.

Quarantine status

no quarantine for Phytophthora syringae as it is very prevalent and widely distributed around the world

Additional references and links

Phytophthora syringae in OSU Phytophthora Online course: Training for Nursery Growers. Oregon State University.

Fact sheet author

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