Phytophthora tentaculata

Name and publication

Phytophthora tentaculata Kröber & Marwitz (1993)

Kröber H and Marwitz R. 1993. Phytophthora tentaculata sp. nov. und Phytophthora cinnamomi var. parvispora var. nov. zwei neue Pilze von Deutschland. Z. Pflanzenk. Pflanzen. 100: 250–258.


from Kröber and Marwitz (1993)




tentaculatus = “tentacles elongated,” refers to the hypha of the diclinous antheridia


Type: GERMANY, from Chrysanthemum frutescens L. (Compositae), collected by R. Marwitz in Frankfurt/Main in 1990, BBA 65425 (Institut fur Mikrobiologie, Biologische Bundesanstalt für Land- und Forstwirtschaft, Berlin-Dahlem)

Ex-type: no code for the ex-type provided in the original manuscript

Ex-type in other collections

BBA 65425 = CBS 412.96, P8496 (WPC), CPHST BL 29 (Abad) 

Molecular identification

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

Phytophthora tentaculata isolate CPHST BL 29 (= P8496 WPC) = ITS rDNA MG865591, COI MH136983

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

Clade 1b

Morphological identification

Colonies and cardinal temperatures

Colony morphology on CMA, PDA, and V-8 agar with no distinctive pattern. The minimum temperature for growth is 6°C, optimum 20–25°C, and maximum 30°C.

Conditions for growth and sporulation

Oogonia form abundantly in culture.

Asexual phase

Sporangia papillate, some bipapillate; caducous with short pedicels; ovoid, obpyriform, or distorted shapes (25–60 µm length x 15–45 µm width) many with elongated necks; originated in unbranched or simple sympodial sporangiohores. Hyphal swellings are small, intercalary, and with radiating hyphae. Chlamydospores spherical (20–45 µm diam.), intercalary or terminal.

Sexual phase

Homothallic. Oogonia smooth-walled, globose (20–49 µm diam.); antheridia paragynous, one to two, rarely three per oogonium, spherical, ellipsoid, or irregular (20–35 µm), often attached distant from the oogonial stalk, diclinous antheridia very common, amphigynous antheridia occasionally produced; oospores plerotic, aplerotic, or slightly aplerotic, spherical (14–38 µm diam.).

Most typical characters

Phytophthora tentaculata is characterized by the presence of hyphal swellings and by the shape of the caducous sporangia.

Specimen(s) evaluated

Phytophthora tentaculata ex-type CPHST BL 29, duplicate of P8496 (World Phytophthora Collection)

Hosts and distribution

Distribution: Asia (China), Europe (Italy, Spain, Germany), North America (USA: CA)
Substrate: roots, stems
Disease note: root rot, stem rot. Heavily infected plants are killed (Kroeber & Marwitz, 1993).
Host: Chrysanthemum spp., Santolina (Asteraceae), Mimulus aurantiacus (Phrymaceae), Verbena (Verbenaceae)

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

Quarantine status

USA: This species was listed as a species of concern during the 2009 Phytophthora prioritization project conducted by USDA APHIS PPQ CPHST PERAL (Schwartzburg et al.).

Phytophthora tentaculata is also 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