Phytophthora macilentosa

Name and publication

Phytophthora macilentosa Yang, Copes & Hong (2014)

Yang X, Copes WE, and Hong C. 2014. Two novel species representing a new clade and cluster of Phytophthora. Fungal Biology 118: 72–82.

Corresponding author: Xiao Yang


from Yang et al. (2014)




refers to the elongated sporangia with great length to width ratio frequently produced by this species


Type: UNITED STATES OF AMERICA, recovered from the middle of water column in a nursery reservoir, Mississippi, February, 2012; holotype ATCC MYA-4945

Ex-type: 58A7

Sequences for ex-type in original manuscript: 58A7 = ITS rDNA KF192700, cox1 KF192708

Ex-type in other collections

58A7 = P19993 (WPC), CPHST BL 125 (Abad), 58A7 (Yang)

Molecular identification

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

Phytophthora macilentosa isolate CPHST BL 125 (= P19993 WPC) = ITS rDNA MG865527, COI MH136922

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

Clade 9a

Morphological identification

adapted from Yang et al. (2014)

Colonies and cardinal temperatures

Minimum temperature for growth is 10°C, optimum 30°C, and maximum 37°C. 

Conditions for growth and sporulation

Phytophthora macilentosa produce abundant sporangia in V8 cultures flooded with 10% soil solution.

Asexual phase

Sporangia nonpapillate, persistent; obpyriform, ovoid, limoniform, ellipsoid, pyriform, and distorted shapes such as peanut-shaped; showing internal, nested, and extended proliferation. Hyphal swellings catenulate or elongated with irregular shapes are produced in old cultures. Chlamydospores absent.

Sexual phase


Addtional specimen(s) evaluated

Phytophthora macilentosa CPHST BL 125, duplicate of P19993 (World Phytophthora Collection), which is a duplicate of ATCC MYA-4945

Hosts and distribution

Distribution: North America (USA: CT, MS)
Substrate: isolated from water

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

Additional references and links

Fact sheet author

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