Phytophthora richardiae (to be updated 2022)

Name and publication

Phytophthora richardiae Buisman (1927)

Buisman CJ. 1927. Root rots caused by Phycomycetes. Mededeelingen van bet Phytopathologisch Laboratorium "Willie Commelin Scholten", Baarn, 11: 1–51.


Buisman C. 1927. Root rots caused by Phycomycetes. Thesis University of Utrecht 88, 51pp. Meded. pkytopath: lab. Willie Commelin Scholten 11: 7.





from Buisman (1927)

Type: NETHERLANDS collected from calla lily (Zantedeschia aethiopica) showing decay in nurseries.

Ex-type: no code indicated in original manuscript, Buisman 1927

Well-authenticated specimen selected by Gloria Abad:
CPHST BL 76 = P7789 (WPC) = from Zantedeschia aethiopica

Well-authenticated selected specimen in other collections

IMI340618 = P7789 (WPC), CPHST BL 76 (Abad) (in Clade 10a)

NOTE: Original publication of Phytophthora richardiae indicates the origin in the Netherlands, and Index Fungorum ("Citations in published lists or literature: Petrak's Lists volume 3 Page Image in Published List") also indicates the Netherlands. 

Specimens CBS 240.30, ATCC 60353, P642, and 45F5 (Yang et al. 2017) indicate origin in the USA, and sequences indicate the position in Clade 8a. Nomenclature of P. richardiae is under revision.

NOTE: IMI 340618 indicates that "a culture is available from the CABI Culture Collection", but no culture for Phytophthora richardiae was available at CABI Collection (3.21.18).

Molecular identification

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

Phytophthora richardiae isolate CPHST BL 76 ( = P7789 ) ITS rDNA MK496521, COI MH136974

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

Clade 10a

Morphological identification

Colonies and cardinal temperatures

Colony morphology on PDA, V8, and MEA with non-distinct pattern. Minimum growth temperature 10°C, optimum 25°C, and maximum 32°C.

Conditions for growth and sporulation

Sporangia produced on plugs of culture media flooded in soil extract.

Asexual phase

Sporangia nonpapillate; persistent; globose, ovoid, ellipsoid (22–71 L x 15–40 W µm), some with tapered base; showing nested and extended internal proliferation; originated in unbranched or in simple sympodial sporangiophores. Hyphal swellings globose, subglobose, sometimes with radiating hyphae, sometimes catenulate. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia smooth-walled, globose (29–48 µm diam); antheridia predominantly amphigynous and occasionally paragynous, spherical, ovoid, club-shaped sometimes with digitate projections; oospores plerotic (26–45 µm diam), oospore wall thick.

Most typical characters

Phytophthora richardiae is characterized by the sporangia shape and proliferation, and the morphological characters of the antheridia.

Specimen(s) evaluated

Phytophthora richardiae CPHST BL 76, duplicate of P7789 (World Phytophthora Collection)

Hosts and distribution

Distribution: Asia, Australia, Europe, North America (USA)
Substrate: roots
Disease Note: root rot
Host: Zantedeschia spp. (Araceae); also Robinia (Fabaceae), Asparagus (Asparagaceae), Daucus carota (carrot, Apiaceae), and Solanum lycopersicum (tomato, Solanaceae) (Erwin & Ribeiro 1996)

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

Additional info:
Host: Zantedeschia aethiopica

Additional references and links

Fact sheet author

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