Phytophthora mekongensis

Name and publication

Phytophthora mekongensis Cacciola & Hoa (2017)

Cacciola SO, La Spada F, Hoa NV, Jung MH, and Scanu B. 2017. Phytophthora mekongensis Cacciola & N.V. Hoa, sp. nov. Fungal Planet description sheet: 615. Persoonia 38: 363. In Crous et al. 2017. Fungal Planet description sheets: 558–624. Persoonia 38: 240–384.

Cacciola SO, La Spada F, Hoa NV, Jung MH, and Scanu B. 2018. Nomenclartrural novelties. Index Fungorum 367: 1-1.

Corresponding author:


from Cacciola et al. (2017)


MB554524  (Cacciola et al. 2018)

MB820796 (old code Cacciola et al. 2017)


refers to the area from where the species was isolated, Mekong River Delta in Vietnam


Type: SOUTHERN VIETNAM, Vĩnh Long province, Mekong Delta region, from Citrus grandis (syn.: C. maxima) fruit, 2012, A. De Patrizio & G. Magnano di San Lio (holotype CBS 135136, Cacciola et al 2018)

Ex-type: PF6a2

Sequences for ex-type in original manuscript:  ITS KC875838 (as Phytophthora aff. meadii AdP-2013 isolate PF6a2); COI KT366920 (as Phytophthora sp. IP-2015 isolate PF6a2)

Ex-type in other collections


Molecular identification

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

Phytophthora aff. meadii AdP-2013 isolate PF6a2 = ITS KC875838 

Phytophthora sp. IP-2015 isolate PF6a2 = COI KT366920 

Sequences for ex-type in other sources
  • NCBI: Phytophthora PF6a2
  • Phytophthora Database: Phytophthora mekongensis
  • EPPO-Q-bank: Phytophthora mekongensis
  • BOLDSYSTEMS: Phytophthora mekongensis (barcoding COI & ITS)
Position in ITS phylogenetic tree

Clade 2a

Morphological identification

adapted from Cacciola et al. (2017)

Colonies and cardinal temperatures

Colony morphology on V8A is stellate to rosaceous, and on PDA stellate. Minimum growth temperature 12°C, optimum 28°C, and maximum 36°C.

Conditions for growth and sporulation

Sporangia produced on V8-agar (V8A) flooded with both distilled water and non-sterile soil extract.

Asexual phase

Sporangia semipapillate, frequently bipapillate and trilobed; often caducous with medium pedicel (5–15 μm); limoniform, ovoid-obpyriform, ellipsoid to fusiform (25–50 μm length × 20–36 μm width); showing a conspicuous basal plug at the point where the pedicel attaches to the sporangium; originated in dense sympodial sporangiophore. Hyphal swellings and chlamydospores not reported.

Sexual phase


Hosts and distribution

Distribution: Asia (Vietnam)
Substrate: roots, fruit
Disease note: root rot, fruit rot
Host: Citrus grandis (Rutaceae)

Retrieved January 31, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

Puglisi et al. 2017. Two previously unknown Phytophthora species associated with brown rot of Pomelo (Citrus grandis) fruits in Vietnam. PLOS

Fact sheet author

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