Contact Info

Primary Title: 
Senior Instructor II
Email Contact: 
Voice Contact: 
(541) 737-5542 x3472
Office/Lab: Cordley 1076/1089


M.S., Wisconsin-Madison, 1984.


Research Description: 

Research and Extension Area: Diagnosis of diseases and disorders of plants submitted to the OSU Plant Clinic; chemical and non-chemical control recommendations.

  • Diagnostic techniques, etiology of new diseases. Since 2002 we have had on-going research projects looking at detection, epidemiology, and management of disease of ornamentals due to Rhodococcus fascians and Agrobacterium tumefaciens.

Research Group Members

Faculty Research Assistants/Associates

  • Maryna Serdani, Senior Faculty Research Assistant

Post-doctoral Scholars

  • William Thomas

Undergraduate Assistants

  • Joey DeShields
  • Alaina Floor
  • Shelby Porter
  • Sierra Purnell
  • Eric Renteria
  • Quintin Russell
  • Samson Tong
  • Mackenzie Trzil


Creason A.L., Davis E.W. II, Putnam M.L., Vandeputte O.M. and Chang J.H. 2014. Use of whole genome sequences to develop a molecular phylogenetic framework for Rhodococcus fascians and the Rhodococcus genus. Frontiers in Plant Science 5:406. doi: 10.3389/fpls.2014.00406 (

Creason A.L., Vandeputte O.M., Savory E.A., Davis E.W. II, Putnam M.L., et al. 2014. Analysis of genome sequences from plant pathogenic Rhodococcus reveals genetic novelties in virulence loci. PLoS ONE 9(7): e101996. doi:10.1371/journal.pone.0101996 (

Gent, D.H., Mueller-Warrant, G.M., Woods, J.L., Putnam, M.L., and Twomey, M.C. 2013. Red crown rot of hop in Oregon caused by Phomopsis tuberivora. Plant Health Progress. doi:10.1094/PHP-2013-0624-01-BR

Conner, K.N., Olive, J., Zhang, L., Jacobi, J., and Putnam, M.L. 2013. First report of bacterial gall on Loropetalum chinense caused by Pseudomonas savastanoi in the United States. Plant Disease 97:835

Serdani, M., Curtis, M.,Miller, M.L., Kraus, J., and Putnam, M. L. 2013. Loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR) methods for specific and rapid detection of Rhodococcus fascians. Plant Disease 97:517-529

Gent, D.H., Woods, J.L., and Putnam, M.L. 2012. New outbreaks of Verticillium wilt on hop in Oregon caused by nonlethal Verticillium albo-atrum. Plant Health Progress doi:10.1094/PHP-2012-0521-01-RS.

Kropf, S.M., Putnam, M.L., Serdani, M., Twomey, M.C., Woods, J.L., and Gent, D.H. 2012. Sclerotinia wilt of hop (Humulus lupulus) caused by Sclerotinia sclerotiorum in the Pacific Northwest United States. Plant Disease, 96:583.

Harveson, R.M., Santra, D.K., Putnam, M.L., Curtis, M., and Pavlista, A.D. 2011. A New Report for Downy Mildew [(Hyaloperonospora camelinae Gäum.) Göker, Voglmayr, Riethm., M. Weiss & Oberw. 2003] of Camelina [Camelina sativa (L.) Crantz] in the High Plains of the United States. Plant Health Progress doi:10.1094/PHP-2011-1014-01-BR.

Putnam, M. L., Serdani, M., Curtis, M., & Angima, S. (2011). Phytophthora leaf blight - a new disease of California wax-myrtle (Morella californica) in Oregon, USA caused by a Phytophthora species. New Zealand Journal of Forestry Science, 41 Suppl., S57-S63. 

Tisserat, N., Cranshaw, W., Putnam, M.L., Pscheidt, J., Leslie, C.A., Murray, M., Hoffman, J., Barkley, Y., Alexander, K., and Seybold, S.J. 2011. Thousand cankers disease is widespread in black walnut in the Western United States. Plant Health Progress doi:10.1094/PHP-2011-0630-01-BR.

Kraus, J., Cleveland, S., Putnam, M.L. , Keller, K.E., Martin, R.R., and Tzanetakis, I.E. 2010. A new Potyvirus sp. Infects Verbena exhibiting leaf mottling symptoms. Plant Disease 94:1132-1136.      

Miller, M.L. and Putnam, M.L . 2010. Sorbaria sorbifolia is a new host for Rhodococcus fascians . Plant Health Progress Online: doi:10.1094/PHP-2010-0408-01-BR.

Serdani, M., Putnam, M.L ., and Curtis, M. 2010. First report of twig canker of blueberry caused by Sporocadus lichenicola (Corda) in Oregon. Plant Health Progress doi:10.1094/PHP-2010-0315-02-BR.

Davis, R.E., Dally, E.L., Zhao, Y., Lee, I.-M., Detweiler, A.J., and Putnam, M.L . 2010. First report of a new subgroup 16SrIX-E (' Candidatus Phytoplasma phoenicium '-related) phytoplasma associated with juniper witches' broom disease in Oregon, USA. Plant Pathology. Online: .  

Putnam, M.L. , Serdani, M., Ehrensing, D., and Curtis, M. 2009. Camelina infected by downy mildew ( Hyaloperonospora camelinae ) in the Western United States: A first report. Plant Health Progress. Online: doi:10.1094/PHP-2009-0910-01-BR.

Kraus, J., Tzanetakis, I.E., Putnam, M.L. , and Martin, R.R. 2008. Complete nucleotide sequence of an isolate of coleus vein necrosis virus from verbena. Archives of Virology 153:381-384.

Jordan , R.L., Guaragna, M.A., Van Buren, T., and Putnam, M.L . 2008. First Report of a New Potyvirus, Tricyrtis virus Y , and Lily virus X Potexvirus, in Tricyrtis formosana in the United States . Plant Disease 92:648.

Jordan , R.L., Guaragna, M.A., and Putnam, M. 2008. Detection and Molecular Characterization of New and Emerging Potyviruses of Ornamental Plants. Acta Horticulturae (in press).

Depuydt, S., Putnam, M ., Hosters, M., and Vereecke, D. 2008. Rhodococcus fascians , an Emerging Threat for Ornamental Crops. In: Floriculture, Ornamental and Plant Biotechnology: Advances and Topical Issues, Vol V.  Global Science Books.

Putnam, M.L . and Miller, M.L. 2007. Rhodococcus fascians in herbaceous perennials. Plant Disease 91:1064-1076.

Putnam, M.L ., and Glawe, D.A. 2007. New North American records of anamorphic powdery mildew fungi (Erisiphales) parasitizing species of Leucothoë and Limnanthes. Pacific Northwest Fungi 2:1-6.

Guaragna, M.A., Jordan, R. and Putnam, M.L . 2006. First molecular evidence of the occurrence of a pea mosaic strain of Bean yellow mosaic virus in Verbena x hybrida. Acta Hort (ISHS) 722:305-312.

Putnam, M.L . and Miller, M. 2006. Pathogenic isolates of Rhodococcus fascians from new hosts in the United States . Plant Dis. 90:526.

Putnam, M.L. and Miller, M. 2006. Is it crown gall or leafy gall?  Digger, 50:39-46.

Angeles, G., Adams , G.C., and M.L. Putnam . 2006. Effect of Neofabraea alba on bark and wood anatomy of Fraxinus spp. IAWA Journal 27:409-418.

Putnam, M.L. and G.C. Adams 2005. Phlyctema vagabunda causes coin canker of ash ( Fraxinus spp.) in North America . Plant Dis. 89:773

Putnam, M.L. 2005 . Allantophomopsis lycopodina - a new aerial pathogen of Lingonberry ( Vaccinium vitis-idaea ) Plant Pathology 54:258.

Putnam, M.L . 2004. First report of stem rot of rosemary caused by Sclerotinia sclerotiorum in the United States . Plant Pathology 53:252.

Guaragna, M.A., R.L. Jordan, and M.L. Putnam. 2004. First report of Bean yellow mosaic virus (Pea mosaic strain) in Verbena x hybrida. Plant Disease 88:574.

Glawe, D.A., J.R. Glass, and M.L. Putnam. 2004. First report of white rust of Lunaria annua caused by Albugo candida in North America. Plant Health Progress. Doi:10.1094?PHP-2004-0317-01-HN.

Rossman, A.Y., L.A. Castlebury, and M.L. Putnam. 2004. First report of ash anthracnose caused by Discula fraxinea in Oregon. Plant Disease 88:222.

Bronson, J.J., G.R. Stanosz, and M.L. Putnam. 2003. First report of Sirococcus conigenus on deodar cedar in Oregon. Plant Disease 87:1006

Putnam, M.L., and L. J. du Toit. 2003. First report of Alternaria blight caused by Alternaria panax on Ginseng (Panax quinquefolius L) in Oregon and Washington, USA. Plant Pathology 52:406.

David F. Farr, D. F. , L. A. Castlebury, A. Y. Rossman, and M. L. Putnam. (2002) A new species of Phomopsis causing twig dieback of Vaccinium vitis-idaea (lingonberry). Mycological Research 106:745-752.

Rossman, A.Y., L. A. Castlebury, G. C. Adams, and M. L. Putnam. (2002) Phlyctema vagabunda isolated from coin canker of ash trees in Michigan. Plant Disease 86:442.

Griesbach, J.A., M. Putnam, and D. Driesner. First Report of Garlic Rust Caused by Puccinia allii in Oregon. (2001) Plant Disease 85:919

Putnam, M.L. 2000. Leaf blight and stem dieback of St. John’s-wort caused by Diploceras
in Oregon: First US report. Plant Disease 84:1250.

Stone, J.K., M.L. Putnam, and L.E. Petrini. 2000. First report of Anthostomella pedemontana from North America. Mycotaxon LXXIV:505-506.

Putnam, M.L. 1999. Bacterial blight, a new disease of Lobelia ricardii caused by Pseudomonas cichorii. Plant Disease 83:966.

Putnam, M.L. 1999. Chlorotic spotting on cherry leaves: possible causes. Crop Protection 18:589-594.

Putnam, M.L and F. Crowe. 1999. Verticillium dahliae, a cause of wilt in Echinacea purpurea. Plant Disease 83:877.

Putnam, M.L. 1999. A new foliar blight of Douglas-fir, grand fir, and noble fir caused by a binucleate Rhizoctonia-like fungus. Plant Disease 83:200.

Putnam, M.L. 1998. Pseudomonas syringae leaf blight, a new disease of Kalmia latifolia. Plant Disease 82:1171.

Reddick, B.B., M.L. Putnam, and L.F. Habera. 1997. Natural infection of field-grown daikon radish (Raphanus sativus L.) crops by turnip crinkle virus in North America. J. Phytopathology 145:379-381.