Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): N. J. Grünwald; S. Werres; E. M. Goss; C. R. Taylor; V. J. Fieland
    Date: 2012
    Source: Plant Pathology. 61(3):610-622
    Publication Series: Scientific Journal (JRNL)
    PDF: View PDF  (919.35 KB)


    A new Phytophthora species was detected (i) in the USA, infecting foliage of Kalmia latifolia, (ii) in substrate underneath Pieris, and (iii) in Germany in soil samples underneath Aesculus hippocastanum showing disease symptoms. The new species Phytophthora obscura sp. nov. is formally named based on phylogenetic analysis, host range, Koch's postulates and morphology. Phytophthora obscura is homothallic with paragynous antheridia and semipapillate sporangia. It is genetically closely related to P. syringae and P. austrocedrae and together these three species define a new Phytophthora subclade 8d, with significant support for all genetic loci analysed including seven nuclear genes and the mitochondrial gene coxII. The morphological and ecological characteristics are very similar to P. syringae, and it is likely that P. obscura was not described earlier because it was identified as P. syringae. Artificial inoculations indicated that horse chestnut, kalmia, pieris and rhododendron might be hosts, and Koch’s postulates were confirmed for kalmia from which it was isolated. This pathogen was named after its elusive nature since it has to date rarely been detected in the US and Germany.

    Publication Notes

    • You may send email to to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    Grünwald, N. J.; Werres, S.; Goss, E. M.; Taylor, C. R.; Fieland, V. J. 2012. Phytophthora obscura sp. nov., a new species of the novel Phytophthora subclade 8d. Plant Pathology. 61(3):610-622. doi: 10.1111/j.1365-3059.2011.02538.x


    Google Scholar


    Aesculus hippocastanum, Kalmia latifolia, oomycete, Pieris, Rhododendron, taxonomy

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page