Name and publication
Phytophthora fallax Dobbie & Dick (2006)
Dick MA, Dobbie K, Cooke DEL, and Brasier CM. 2006. Phytophthora captiosa sp. nov. and P. fallax sp. nov. causing crown dieback of Eucalyptus in New Zealand. Mycol. Res. 110: 393–404 (pg 398).
Corresponding author e-mail: email@example.com
from Dick et al. (2006)
‘fallax’ = elusive, referring to the elusive nature of the fungus and the disease it causes
Type: NEW ZEALAND, Southland, Katea, Owaka Valley, culture isolated from leaves of alpine-ash (Eucalyptus delegatensis), 3 June 1997, collected by R. Thum A0049703 NZFRI-M 5216-holotypus deposited at the New Zealand Forest Research Institute Herbarium – Mycology)
Ex-type: NZFS 310L deposited in the New Zealand Forest Research Institute Culture Collection, also deposited in the International Collection of Micro-organisms from Plants (ICMP 15575), and the World Phytophthora Collection
Sequences for ex-type in original manuscript: NZFS 310L = ITS DQ297391
NOTE: In the original paper, P. fallax was reported as being deposited in the World Phytophthora Collection as WPC P10721. However, in the WPC database, P10721 corresponds to P. captiosa and isolate P10722 corresponds to the type of P. fallax (G. Abad search on 5/12/15).
Ex-type in other collections
Voucher sequences for barcoding genes (ITS rDNA and COI) of the ex-type (see Molecular protocols page)
Sequences of selected specimen
Sequences for ex-type in other sources
- NCBI: Phytophthora fallax CPHST BL 63
- NCBI: Phytophthora fallax P10722
- NCBI: Phytophthora fallax NZFS310L
- Phytophthora DATABASE: Phytophthora fallax PD_02040 = P10722
- EPPO-Q-bank: Phytophthora fallax CBS 119109
- BOLDSYSTEMS: Phytophthora fallax PHYTO074-10 = P10722 (barcoding COI & ITS)
Position in ITS phylogenetic tree
adapted from Dick et al. (2006)
Colonies and cardinal temperatures
Colony morphology after 7 days on V8-A, PDA, and MEA with light rosaceous pattern and relatively slow growth. Minimum growth temperature 2°C, optimum 25°C, and maximum 30°C.
Conditions for growth and sporulation
Sporangia nonpapillate, persistent, obpyriform to distorted, often with a distinctive elongated neck and conspicuous basal plug (44–60 L x 27–38 W µm), proliferating both internally and externally, and originated in unbranched or simple sympodial sporangiophore. Hyphal swellings absent. Chlamydospores spherical, terminal (12–26 µm diam).
Homothallic. Oogonia smooth-walled, spherical (30–36 µm diam); antheridia predominantly paragynous; sometimes the distorted hyphae of paragynous antheridia coils around the oogonial stalk and is difficult to determine; paragynous antheridia globose (6–10 µm diam), most often attached near the oogonial stalk. Amphigynous antheridia are cylindrical (16–30 L x 12–13 W µm). Oospores are initially plerotic, becoming aplerotic with age (29–34 µm diam).
Most typical characters
Phytophthora fallax is characterized by the production of obpyriform sporangia with a distinctive elongated neck, and by the presence of antheridia predominantly paragynous with hyphae sometimes coiling around the oogonial stalk.
Additional specimen(s) evaluated
Phytophthora fallax ex-type CPHST BL 63, duplicate of P10722 (World Phytophthora Collection)
Hosts and distribution
Distribution: Australia, New Zealand
Substrate: living leaves; also twigs, petioles, seed capsules, and peduncles
Disease note: associated with crown disease
Host: Eucalyptus spp. (Myrtaceae)
Retrieved January 30, 2018 from U.S. National Fungus Collections Nomenclature Database.
Additional references and links
- Phytophthora DATABASE: Phytophthora fallax
- EPPO-Q-bank: Phytophthora fallax
- SMML USDA-ARS: Phytophthora fallax
- EPPO Global Database: Phytophthora fallax
- CABI Invasive Species Compendium: Phytophthora fallax
- Encyclopedia of Life (EOL): Phytophthora fallax
- Index Fungorum (IF): Phytophthora fallax
- Plantwise Knowledge Bank:Phytophthora fallax
Fact sheet author
Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Beltsville Laboratory, United States of America