College of Agricultural, Human, and Natural Resource Sciences

Department of Plant Pathology

Dr. Dean Glawe

Research Highlight

Faculty Web Page

Systematics and Biology of Economically Important Fungi in the Pacific Northwest

With an estimated 1.5 million species, fungi are among the world’s most diverse organisms (1).  Fungi function as symbionts, pathogens, and decomposers in natural ecosystems. Fungi also are extremely important economically.  About 13,000 species of plant pathogenic fungi occur in the USA where they cause most of the $33 billion annually lost to plant diseases (2). Plant pathogenic fungi pose significant risks to the Washington State economy; the annual farm gate value for Washington crops exceeds $3.8 billion (4), and agriculture and associated activities are responsible for about 500,000 jobs (3).  With changes posed by globalization, the advent of new crops (such as super-premium fruit varieties), and restrictions on the use of fungicides because of environmental concerns, the plant-based industries of the region continually need new information about the diagnosis and control of plant pathogenic fungi.

Dr. Glawe’s research program on economically important fungi began at Washington State University in 2002.  In 2006 this WSU program was relocated to the Seattle campus of the University of Washington to facilitate collaborations with scientists at that University.  As a modern, comprehensive program in fungal systematics it employs extensive field collecting, digital imagery, DNA sequence analysis, and internet and database technologies.  The program benefits from strong regional and international collaborations and has two major components:

Pacific Northwest Fungi Database:

The goal of this project is to inventory the fungi of the Pacific Northwest and to use this information to develop an online guide to the region’s fungi.  The Pacific Northwest Fungi Database (was first posted online in 2004 and is now in its second version. The initial content was compiled by Professor C. Gardener Shaw for his Host Fungus Index of the Pacific Northwest. The Database currently includes information on about 5,000 species of fungi.  Plans are under way to expand coverage to under-represented groups of fungi such as lichens, animal pathogens, and fungi on grasses.  Because the Pacific Northwest is thought to be home to 15,000-20,000 species of fungi, these activities are expected to continue for many years.

A related effort has been to help develop the new online journal Pacific Northwest Fungi. The journal began operation in May, 2006 and will be a primary source of new information for the Database. Topics covered include the taxonomy, nomenclature, ecology, and biogeography of fungi. The journal exploits advantages of modern digital and web-based technologies to provide authors and readers with fast, economical, and widely disseminated publication of new mycological information. Systematics of Erysiphales (Powdery Mildew Fungi)The goal of this project is to produce a taxonomic monograph of the Erysiphales (powdery mildew fungi) occurring in North America.  (A taxonomic monograph is a guide to classification and identification.)  Powdery mildews occur on many plants of agricultural significance. For example, the American Phytopathological Society’s lists of common names for plant diseases identify powdery mildews as pathogens of 70% of the crops listed.   Powdery mildew diseases rank among the most important threats to production of wine grapes, tree fruits, hops, and many ornamental plant species.  Despite their prevalence and economic importance, there is no taxonomic monograph for powdery mildews in North America exists. The lack of up-to-date taxonomic information is a significant impediment to researchers and others concerned with powdery mildew biology, diagnosis, and control.Results so far suggest that 150-200 species of Erysiphales occur in the Pacific Northwest, many more than the several dozen known previously. Powdery mildew pathogens on potato, AkebiaGaillardiaMahoniaScabiosa, and teasel were documented for the first time in North America.  Powdery mildew of the ecologically-important salt marsh plant Triglochin was documented for the first time in the world.  These and other newly encountered plant pathogenic fungi have been documented in a series of publications in the American Phytopathological Society’s online journal Plant Health Progress. A paper on Erysiphales of Alaska will be published in the near future.


North American Fungi Online Journal:

Pacific Northwest Fungi Database:


Selected recent publications:

  • Dugan, F., M., and D. A. Glawe.  2006.  First Report of Powdery Mildew on Dipsacus sylvestris Caused by Sphaerotheca (Podosphaeradipsacearum in North America. Plant Health Progress doi:10.1094/PHP-2006-0607-02-BR.
  • Falacy, J. S., and Glawe, D. A. 2003. First report of powdery mildew ofLigustrum japonicum (Japanese privet) caused by Microsphaera syringae(Erysiphe syringae) in North America. Online. Plant Health Progress doi:10.1094/PHP-2003-1210-01-HN.
  • Glawe, D. A. 2003. First Report of powdery mildew of Magnolia caused byMicrosphaera magnifica (Erysiphe magnifica) in the Pacific Northwest. Online.Plant Health Progress doi:10.1094/PHP-2003-0512-02-HN.
  • Glawe, D. A. 2003. First report of powdery mildew of Mahonia aquifoliumcaused by Microsphaera berberidis (Erysiphe berberidis) in North America. Online. Plant Health Progress doi:10.1094/PHP-2003-0206-01-HN.
  • Glawe, D. A. 2003. First report of powdery mildew of Nandina domesticacaused by Microsphaera berberidis (Erysiphe berberidis) in the Pacific Northwest. Online. Plant Health Progress doi:10.1094/PHP-2003-1023-01-HN.
  • Glawe, D. A. 2003. First report of powdery mildew of Platanus occidentaliscaused by Microsphaera platani (Erysiphe platani) in Washington State. Online.Plant Health Progress doi:10.1094/PHP-2003-0818-01-HN.
  • Glawe, D. A. 2004. First report of powdery mildew of Hypericum perforatum(St. John’s-wort) caused by an anamorphic Microsphaera species in the Pacific Northwest. Online. Plant Health Progress doi:10.1094/PHP-2004-0707-01-HN.
  • Glawe, D. A. 2004. First report of powdery mildew of Lycium chinense (Chinese matrimony vine) caused by Arthrocladiella mougeotii in the Pacific Northwest. Online. Plant Health Progress doi:10.1094/PHP-2004-1208-01-HN.
  • Glawe, D. A.  2004.  First report of powdery mildew of Myosotis sylvatica(wood forget-me-not)caused by Golovinomyces cynoglossi (Erysiphe cynoglossi)in Washington state.  Submitted to Plant Health Progress.  Online. Plant Health Progress doi:10.1094/PHP-2004-1124-01-HN.
  • Glawe, D.A., F.M. Dugan,Y. Liu, and J.D. Rogers.  2005.  First record and characterization of a powdery mildew (Erysiphales) on a member of the Juncaginaceae: Leveillula taurica on Triglochin maritima. Mycological Progress4: 291-298.
  • Glawe, D. A., and J. R. Glass.  2004.  First Report of Powdery Mildew of Akebia quinata Caused by Microsphaera akebiae (Erysiphe akebiae) in North America. Plant Health Progress doi:10.1094/PHP-2004-0316-01-HN.
  • Glawe, D. A., and G. G. Grove. 2005. First report of powdery mildew ofScabiosa columbaria (dove pincushions) caused by Erysiphe knautiae in North America. Online. Plant Health Progress doi:10.1094/PHP-2005-1024-01-BR.
  • Glawe, D. A., and G. G. Grove, and M. Nelson.  2006.  First Report of Powdery Mildew of Coreopsis Caused by Golovinomyces cichoracearum in the Pacific Northwest.  Online. Plant Health Progress doi:10.1094/PHP-2006-0405-01-BR.
  • Glawe, D. A., and G. G. Grove, and M. Nelson.  2006.  First Report of Powdery Mildew of Gaillardia Caused by Leveillula taurica in North America.  Plant Health Progress. In press.
  • Glawe, D. A., and R. Hummel.  2006.  New North American host records forSeifertia azaleae.  Pacific Northwest Fungi 1(5): 1-6.  Online.  doi: 10.2509/pnwf.2006.001.005.
  • Glawe, D. A., R. Hummel, and G. Jack.  2003.  First Report of Powdery Mildew of Kalanchoe blossfeldiana caused by Sphaerotheca fuliginea in the Pacific Northwest.  Online. Plant Health Progress doi:10.1094/ PHP-2003-0417-02-HN.
  • Glawe, D. A., and G. A. Laursen. 2005. First Report of powdery mildew onCaragana arborescens and Caragana grandiflora in Alaska caused byMicrosphaera (Erysiphe) palczewskii. Online. Plant Health Progress doi:10.1094/PHP-2005-1017-01-BR.
  • Glawe, D. A., Pelter, G. Q., and du Toit, L. J. 2005. First report of powdery mildew of carrot and parsley caused by Erysiphe heraclei in Washington State. Online. Plant Health Progress doi:10.1094/PHP-2005-0114-01-HN.
  • Glawe, D. A., du Toit, L. J., and Pelter, G. Q. 2004. First report of powdery mildew on potato caused by Leveillula taurica in North America. Online. Plant Health Progress doi:10.1094/PHP-2004-1214-01-HN.
  • Glawe, D. A., G. E. Windom, G. G. Grove, and J. S. Falacy. 2003. First report of powdery mildew of Convolvulus arvensis (field bindweed) caused by Erysiphe convolvuli var. convolvuli in North America. Online. Plant Health Progressdoi:10.1094/PHP-2003-1021-01-HN.
  • Hartney, S., D. A. Glawe, F. Dugan, and Joseph Ammirati.  2005.  First Report of Powdery Mildew on Corylus avellana caused by Phyllactinia guttata in Washington State.  Online. Plant Health Progress doi:10.1094/PHP-2005-1121-01-BR.
  • du Toit, L. J., D. A. Glawe, and G. Q. Pelter.  2004.  First Report of Powdery Mildew of Onion (Allium cepa) Caused by Leveillula taurica in the Pacific Northwest.  Online. Plant Health Progress doi:10.1094/PHP-2004-1129-01-HN.

References cited:

Hawkworth, D. L.  2001 The magnitude of fungal diversity: the 1.5 million species estimate revisited. Mycological Research 105: 1422-1432

Madden, L. V., and M. Wheelis.  2003.  The threat of plant pathogens as weapons against U.S. crops.  Annual Review of Phytopathology 41: 155-176.

USDA Economic Research Service (n.d.) ViewData.asp?GeoAreaPick=STAWA_Washington

USDA National Agricultural Statistics Service (n.d.)

Updated 2006

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