Phytophthora cryptogea

Name and publication

Phytophthora cryptogea Pethybr. & Laff. (1919)

Pethybridge GH and Lafferty HA. 1919. A disease of tomato and other plants caused by a new species of Phytophthora. Scient. Proc. R. Dubl. Soc. N.S. 15: 487–503.





Pythiomorpha oryzae S. Ito & Nagai, Journal of the Faculty of Agriculture of the Hokkaido Imperial University 32: 51 (1931) [MB273095]


from Pethybridge and Lafferty (1919)

Type: IRELAND, from root and stem of young tomatoes (Lycopersicon esculentum Mill.) submitted from a nursery in the suburbs of Dublin to the Seeds and Plant Disease Division of the Irish Department of Agriculture in early summer 1916. P. cryptogea was also associated with aster and petunias. CBS H-7640 deposited to CBS by G.H. Pethybridge on Nov 1919.

Ex-type: CBS 113.19

Ex-type in other collections

CBS 113.19 P1738 (WPC) A1, P3448 (WPC), IMI 180615, BPIC 1189, CPHST BL 16 (Abad), 61H9 (Yang)

NOTE: IMI 180615 (Ireland) no information for the host, deposit, and date for this isolate in HerbIMI.

Molecular identification

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

Phytophthora cryptogea isolate CPHST BL 16 (= P1738 WPC) = ITS rDNA MG865483, COI MH136878 (This is a COI sequence, but listed as cox1 in NCBI.)

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

Clade 8a

Morphological identification

Colonies and cardinal temperatures

Colony morphology after 7 days on PDA, V-8, and MEA faintly petaloid. Minimum growth temperature 3°C, optimum 24°C, and maximum 30°C.

Asexual phase

Sporangia nonpapillate, persistent, ellipsoid, ovoid, obpyriform, and with distorted shapes (23–38 × 35–62 µm), originated in unbranched or in simple sympodial sporangiophores. Hyphal swellings globose, subglobose, catenulate, and produced in visible networks, some with radiating hyphae. Chlamydospores absent.

Sexual phase

Heterothallic. Oogonia with smooth wall, some with tapered bases, and becoming yellow with age, 28–37 µm; antheridia amphigynous, oval or cylindrical (12–17 × 13–17 µm); oospores plerotic (24–32 µm diam) with thick walls (3.5 µm). 

Most typical characters

Phytophthora cryptogea is characterized by the typical hyphal swellings that are produced in water cultures and turning to dense clusters in old cultures.

Specimen(s) evaluated

Phytophthora cryptogea ex-type CPHST BL 16 (A1), duplicate of P1738 (World Phytophthora Collection) which is a duplicate of CBS 113.19

Phytophthora cryptogea CPHST BL 139 (A2) (G. Abad selected specimen), duplicate of P1380 (World Phytophthora Collection)

Hosts and distribution

Distribution: cosmopolitan
Substrate: roots, stems, corms, leaves
Disease note: damping-off, foot rot, stem rot, leaf rot, wilt
Hosts: multiple hosts, roots/foliage, 141 genera in 49 families

Retrieved January 29, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

Note: some publications could contain isolates of closely related species in the Phytophthora cryptogea/Phytophthora drechsleri complex.

Pethybridge GH, Lafferty HA. 1919. A disease of tomato and other plants caused by a new species of Phytophthora. Scient. Proc. R. Dubl. Soc. N.S. 15: 487–503.

Hong S-B, Jee H-J, Kim S-H, and Go S-J. Evolutionary relationship among cucurbits isolates of Phytophthora cryptogea/Phytophthora drechsleri species complex and related species deduced from rDNA sequence analysis NCBI 02-FEB-2001 ITS: AF228100 (isotype) GGGGACG 1G deletion recheck

Fact sheet author

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