Phytophthora chrysanthemi

Name and publication

Phytophthora chrysanthemi Naher, Watanabe, Chikuo, & Kageyama (2011)

Naher M, Motohash K, Watanabe H, Chikuo Y, Senda M, Suga H, Brasier C, and Kageyama K. 2011. Phytophthora chrysanthemi sp. nov., a new species causing root rot of chrysanthemum in Japan. Mycol. Prog. 10: 21–31.

Corresponding author:


from Naher et al. (2011)




refers to the original host plant of this pathogen


Type: JAPAN, Gifu, Minokamo (36°N, 137°E), from root rot of potting chrysanthemum (Chrysanthemum X morifolium), 2000, collector H. Watanabe, isolate NBRC 104917 (deep-freezing) deposited at the National Institute of Technology and Evaluation - Biological Resource Center, Japan

Ex-type: CBS 123163 = GF749

Sequences for ex-type in original manuscript: Phytophthora chrysanthemi GF749 = ITS AB437135, β-tub AB511995, TEF 1α AB511925, LSU AB465349, HS 90 AB511987, L10 AB511926

Ex-type in other collections

CBS 123163 = GF749 (Kageyama) = P19843 (WPC), CPHST BL 94 (Abad), 61F1 (Yang)

Molecular identification

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

Phytophthora chrysanthemi isolate CPHST BL 94 (= P19843 WPC) = ITS rDNA MG865472, COI MH136868

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

Clade 9a

Morphological identification

adapted from Naher et al. (2011)

Colonies and cardinal temperatures

Colonies on V8-A, PDA, and MEA with no distinctive pattern. Minimum temperature for growth 6°C, optimum 30°C, and maximum 35°C.

Asexual phase:

Sporangia nonpapillate; persistent; ellipsoid, ovoid, or pyriform (24–59 μm long ×16–43 μm wide); with extended, nested, or internal proliferation with 3 to 8 sporangia. Sporangia produced in single or sympodial sporangiophores. Hyphal swellings elongated, irregular to globose, produced lateral and intercalary (up to 67 μm). Chlamydospores spherical terminal, lateral, or intercalary (27–46 μm diam.).

Sexual phase

Homothallic. Oogonia terminal, often laterally sessile and intercalary with smooth walls; mostly spherical or nearly spherical, and occasionally possessing a distinct funnel-shaped stalk (26–46 μm diam.), acquiring a golden brown color with aging; antheridia mostly terminal and occasionally intercalary and predominantly paragynous but sometimes amphigynous; oospore aplerotic, spherical (19–35 μm diam.).

Additional specimen(s) evaluated

Phytophthora chrysanthemi CPHST BL 94 = P19843 (World Phytophthora Collection)

Hosts and distribution

Distribution: Asia (Japan), Europe (Croatia, Germany), North America (USA)
Substrate: stems, roots
Disease note: stem and root rot
Hosts: Chysanthemum (Asteraceae)

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

Quarantine status

Phytophthora chrysanthemi is listed in the U.S. Regulated Plant Pest Table (last modified Nov. 15, 2017).

Additional references and links

Fact sheet author

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