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Lindsey J. du Toit

Vegetable Seed Pathologist, Professor/Extension Plant Pathologist

(60% research: 30% extension: 10% teaching appointment)

Lindsey J. du Toit
WSU Mount Vernon Northwestern Washington Research & Extension Center (NWREC)
16650 State Route 536
Mount Vernon, WA 98273-4768

Tel.: (360) 848-6140
Cell: (360) 391-2407
Fax: (360) 848-6159

Research Specialty and Interests

Epidemiology and management of diseases affecting vegetable seed crops (primarily small-seeded vegetables) in the Pacific Northwest. …more on Lindsey’s program

For information on the Pacific Northwest Vegetable Extension Group, which Lindsey leads.

Watch Washington State University and CAHNRS College Present: Focus on Research

Professional Background

  • PhD, University of Illinois in Urbana-Champaign (plant pathology dissertation on common smut of sweet corn directed by Prof. Jerald Pataky)
  • MS, University of Illinois in Urbana-Champaign (plant pathology thesis on Fusarium root rot of field corn directed by Dr. H.W. Kirby)
  • BS, University of Natal-Pietermaritzburg, South Africa (plant pathology major)


  • 2019 ‘Friend of the Industry’ Award from the Pacific Northwest Vegetable Association in recognition of outstanding service to the vegetable industry in the Pacific Northwest USA
  • American Phytopathological Society (APS) Presidential Team (Vice President, 2017; President-Elect, 2018; President, 2019; Past President, 2020)
  • American Phytopathological Society (APS) Councilor-at-Large (2014-2017)
  • American Phytopathological Society (APS) Syngenta Award for outstanding recent contributions to research/extension in plant pathology (2013)
  • WSU CAHNRS Interdisciplinary Team Excellence Award for the Pacific Northwest Vegetable Extension Group (PNW VEG) (2012)
  • WSU Kenneth J. Morrison Extension Award for outstanding contributions to the improvement of Washington State’s crop production (2009)
  • Alfred Christianson Family Endowed Professorship (2001-05, 2006-10, 2012-17)
  • Robert MacDonald Vegetable Seed Memorial Fund (2003-06, 2008-11, 2013, 2017-20)
  • APS Pacific Division Early Career Award (2006)
  • Member of American Phytopathological Society (chair of Seed Pathology Committee, 2007-09; chair of Diagnostics Committee, 2002-03); International Society of Plant Pathology; Southern African Society of Plant Pathologists

Selected Publications

  • Carmody, S.M., King, K.M., Ocamb, C.M., Fraaije, B.A., West, J.S., and du Toit, L.J. 2020. A phylogenetically distinct lineage of Pyrenopeziza brassicae associated with chlorotic leaf spot of Brassicaceae in North America. Plant Pathology 69:518-537.
  • Liu, B., Stein, L., Cochran, K., du Toit, L.J., Feng, C., Dhillon, B., and Correll, J.C. 2020. Characterization of spinach leaf spot pathogens from several spinach production areas in the U.S. Plant Dis. 104: in press.
  • Synoground, T., Batson, A., Derie, M., Koenick, L.B., Pethybridge, S.J., and du Toit, L.J. 2020. First report of Cercospora leaf spot caused by Cercospora chenopodii on Spinacia oleracea in the USA. Plant Disease 104:976.
  • Knerr, A.J., Wheeler, D., Schlatter, D., Sharma-Poudyal, D., du Toit, L.J., and Paulitz, T.C. 2019. Arbuscular mycorrhizal fungal communities in organic and conventional onion crops in the Columbia Basin of the Pacific Northwest USA. Phytobiomes 2:194-207.
  • Koenick, L.B., Knight, N.L., Vaghefi, N., du Toit, L.J., and Pethybridge, S.J. 2019. Genetic diversity and differentiation in Phoma betae populations on table beet in New York and Washington States. Plant Disease 103:1487-1497.
  • Zou, Z., Zhang, X., Parks, P., Van de Wouw, A. P., du Toit, L.J., and Dilantha Fernando, W.G. 2019. A new subclade of Leptosphaeria biglobosa identified from Brassica rapa. International Journal of Molecular Sciences 20:1668 doi:10.3390/ijms20071668. Article highlighted as Feature Paper in Molecular Plant Sciences.
  • Fukada, H., Derie, M.L., Shishido, M, and du Toit, L.J. 2018. Phomopsis black root rot of cucumber in Washington State caused by Diaporthe sclerotioides. Plant Disease 102:1657.
  • Gatch, E.W., and du Toit, L.J. 2017. Limestone-mediated suppression of Fusarium wilt in spinach seed crops. Plant Disease 101:81-94.
  • Econopouly, B.F., Derie, M.L., Jones, S.S., and du Toit, L.J. 2017. Downy mildew of buckwheat, Fagopyrum esculentum, in the USA caused by Peronospora cf. documetii. Plant Disease 101:391.
  • Moloto, V.M., Goszczynska, T., du Toit, L.J., and Coutinho, T.A. 2017. A new pathovar of Pseudomonas syringae, pathovar allii, isolated from onion plants exhibiting symptoms of blight. European Journal of Plant Pathology 146:591-603.
  • Paulitz, T.C., Knerr, A.J., Carmody, S.M., Schlatter, D., Sowers, K., Derie, M.L., and du Toit, L.J. 2017. First report of Leptosphaeria maculans and Leptosphaeria biglobosa, causal agents of blackleg, on canola in Washington State. Plant Disease 101:504.
  • Alcala, A.C., Paulitz, T.C., Schroeder, K.L., Porter, L.D., Derie, M.L., and du Toit, L.J. 2016. Pythium species associated with damping-off of pea in certified organic fields in the Columbia Basin of central Washington. Plant Disease 100:916-925.
  • Sharma-Poudyal, D., Paulitz, T.C., and du Toit, L.J. 2016. Timing of glyphosate applications to wheat cover crops to reduce onion stunting caused by Rhizoctonia solani. Plant Disease 100:1474-1481. Monthly ‘Editor’s Pick’.
  • Bull, C.T., Ortiz-Lytle, M.C., Ibarra, A.G., du Toit, L.J., and Reynolds, G. 2015. First report of bacterial blight of crucifers caused by Pseudomonas cannabina alisalensis in Minnesota on arugula (Eruca vesicaria subsp. sativa). Plant Disease 99:415.
  • Christianson, C.E., Jones, S.S., and du Toit, L.J. 2015. Screening carrot germplasm for resistance to Xanthomonas hortorum carotae. HortScience 50:341-350.
  • Gatch, E.W., and du Toit, L.J. 2015. A soil bioassay for predicting the risk of spinach Fusarium wilt. Plant Disease 99:512-526.
  • Sharma-Poudyal, D., Paulitz, T.C., and du Toit, L.J. 2015. Evaluation of onion genotypes for resistance to stunting caused by Rhizoctonia solani AG 8. HortScience 50:551-554.
  • Sharma-Poudyal, D., Paulitz, T.C., and du Toit, L.J. 2015. Stunted patches in onion bulb crops in Oregon and Washington: Etiology and yield loss. Plant Disease 99:648-658.
  • Sharma-Poudyal, D., Paulitz, T.C., Porter, L.D., and du Toit, L.J. 2015. Characterization and pathogenicity of Rhizoctonia and Rhizoctonia-like species from pea crops in the Columbia Basin of Oregon and Washington. Plant Disease 99:604-613.
  • du Toit, L.J., and Derie, M.L. 2014. White rust of Echinacea angustifolia and E. purpurea in North America caused by a Pustula species. Plant Disease 98:856.
  • du Toit, L.J., Derie, M.L., and Alcala, A.C. 2014. First report of Pythium sulcatum causing cavity spot in processing carrot crops in the Columbia Basin of Washington State. Plant Disease 98:427.
  • du Toit, L.J., Derie, M.L., Christianson, C.E., Hoagland, L., and Simon, P. 2014. First report of bacterial blight of carrot in Indiana caused by Xanthomonas hortorum pv. carotae. Plant Disease 98:685.
  • Feng, C., Mansouri, S., Bluhm, B. H., du Toit, L.J., and Correll, J.C. 2014. Multiplex real-time PCR assays for detection of spinach seedborne pathogens. Journal of Applied Microbiology: in press.
  • Iglesias-Garcia, A.M., Villarroel-Zeballos, M.I., Feng, C., du Toit, L.J., and Correll, J.C. 2013. Pathogenicity, virulence, and vegetative compatibility grouping of Verticillium isolates from spinach seed. Plant Disease 97:1457-1469.
  • Okubara, P., Harrison, L.A., Gatch, E.W., Schroeder, K., Vandemark, G., and du Toit, L.J. 2013. Development and evaluation of a TaqMan real-time PCR assay for Fusarium oxysporum f. sp. spinaciae. Plant Disease 97:927-937.
  • Patzek, L.J., du Toit, L.J., Paulitz, T.C., and Jones, S.S. 2013. Stunting of onion caused by Rhizoctonia spp. isolated from the Columbia Basin of Washington and Oregon. Plant Disease 97:1626-1635.
  • Temple, T., du Toit, L.J., Derie, M.L., and Johnson, K. 2013. Quantitative molecular detection of Xanthomonas hortorum pv. carotae in carrot seed before and after hot water treatment. Plant Disease 97:1585-1592.
  • du Toit, L.J., and Derie, M.L. 2012. First report of Cladosporium leaf spot of spinach caused by Cladosporium variabile in the winter spinach production region of California and Arizona. Plant Disease 96:1071.
  • Rodriguez-Salamanca, L.M., Enzenbacher, T.B., Derie, M.L., du Toit, L.J., Feng, C., Correll, J.C., and Hausbeck, M.K. 2012. First report of Colletotrichum coccodes causing leaf and neck anthracnose on onions (Allium cepa) in Michigan and the United States. Plant Disease 96:769.
  • Schroeder, B.K., Humann, J.L., and du Toit, L.J. 2012. Effects of postharvest onion curing parameters on the development of sour skin and slippery skin in storage. Plant Disease 96:1548-1555.
  • Villarroel-Zeballos, M.I., Feng, C., Iglesias, A., du Toit, L.J., and Correll, J.C. 2012. Characterization of Verticillium dahliae from spinach seed, and screening for resistance to Verticillium wilt in spinach. HortScience 47:1297–1303.
  • Wohleb, C.H., Waters, T.D, du Toit, L.J., and Schroeder, B.K. 2012. The Washington State University Onion Cultivar Trial: An important resource for Washington onion growers. Acta Horticulturae 969:241-246.
  • Correll, J.C., Bluhm, B.H., Feng, C., Lamour, K., du Toit, L.J., and Koike, S.T. 2011. Spinach: Better management of downy mildew and white rust through genomics. European Journal of Plant Pathology 129:193-205.
  • Dung, J., du Toit, L.J., and Johnson, D.J. 2011. Verticillium wilt of skullcap and potential for pathogen dissemination via seeds and stems. Plant Disease 95:1147-1152.
  • Pataky, J.K., Williams II, M.M., Headrick, J.M., Nankam, C., du Toit, L.J., and Michener, P.M. 2011. Observations from a quarter century of evaluating reactions of sweet corn hybrids in disease nurseries. Plant Disease 95:1492-1506 (Feature Article).
  • Atallah, Z.K., Maruthachalam, K., du Toit, L.J., Koike, S.T., Davis, R.M., Klosterman, S.J., Hayes, R.J., and Subbarao, K.V. 2010. Population analyses of the vascular plant
  • pathogen Verticillium dahliae detect recombination and transcontinental gene flow. Fungal Genetics and Biology 47:416-422.
  • Schroeder, B.K., and du Toit, L.J. 2010. Effects of postharvest onion curing parameters on Enterobacter bulb decay in storage. Plant Disease 94:1425-1430.
  • Schroeder, B.K., Waters, T.W., and du Toit, L.J. 2010. Evaluation of onion cultivars for resistance to Enterobacter cloacae in storage. Plant Disease 94:236-243.
  • Bull, C.T., and du Toit, L.J. 2009. First report of bacterial blight on conventionally and organically grown arugula in Nevada caused by Pseudomonas syringae pv.
  • Plant Disease 93:109.
  • Cummings, J.A., Miles, C.A., and du Toit, L.J. 2009. Greenhouse evaluation of seed and drench treatments for organic management of seedling blight pathogens of spinach. Plant Disease 93:1281-1292.
  • Eastwell, K.C., du Toit, L.J., and Druffel, K.L. 2009. Helleborus net necrosis virus: A new Carlavirus associated with a disease of Helleborus spp. Plant Disease 93:332-338.
  • Koike, S.T., du Toit, L.J., and Derie, M.L. 2009. A leaf blight of chives, caused byBotrytis byssoidea, in California. Plant Disease 93:844.
  • Schroeder, B.K., du Toit, L.J., and Schwartz, H.F. 2009. First report of Enterobacter claocae causing onion bulb rot in the Columbia Basin of Washington State. Plant Disease 93:323.
  • Mou, B., Koike, S.T., and du Toit, L.J. 2008. Screening for resistance to leaf spot diseases of spinach. HortScience 43:1706-1710.
  • Chilvers, M.I., du Toit, L.J., Akamatsu, H., and Peever, T.L. 2007. A real-time PCR seed assay for Botrytis spp. that cause neck rot of onion. Plant Disease 91:599-608.
  • du Toit, L.J., Burger, J.T., McLeod, A., Engelbrecht, M, and Viljoen, A. 2007. Iris yellow spot virus in onion seed crops in South Africa. Plant Disease 91:1203.
  • Chilvers, M.I., and du Toit, L.J. 2006. Detection and identification of Botrytis species associated with neck rot, scape blight, and umbel blight of onion. Online. Plant Health Progress doi:10.1094/PHP-2006-1127-01-DG.
  • Gent, D.H., du Toit, L.J., Fichtner, S.F., Mohan, S.K., Pappu, H.R., and Schwartz, H.F. 2006. Iris yellow spot virus: An emerging threat to onion bulb and seed production. Plant Disease 90:1468-1480.
  • Hernandez-Perez, P., and du Toit, L.J. 2006. Seedborne Cladosporium variabile andStemphylium botryosum in spinach. Plant Disease 90:137-145.
  • Lee, I.-M., Bottner, K.D., Munyaneza, J.E., Davis, R.E., Crosslin, J.M., du Toit, L.J., and Crosby, T. 2006. Carrot purple leaf: A new spiroplasmal disease associated with carrots in Washington State. Plant Disease 90:989-993.
  • Pappu, H.R., du Toit, L.J., Schwartz, H.F., and Mohan, K. 2006. Sequence diversity of the nucleoprotein gene of Iris yellow spot virus (genus Tospovirus, family Bunyaviridae) isolates from the western region of the United States. Archives of Virology 151:1015-1023.
  • du Toit, L.J., Crowe, F.J., Derie, M.L., Simmons, R.B., and Pelter, G.Q. 2005. Bacterial blight of carrot seed crops in the Pacific Northwest. Plant Disease 89:896-907.
  • du Toit, L.J., Derie, M.L., and Hernandez-Perez, P. 2005. Verticillium wilt in spinach seed production. Plant Disease 89:4-11.
  • du Toit, L.J., and Hernandez-Perez, P. 2005. Efficacy of hot water and chlorine for eradication of Cladosporium variabile, Stemphylium botryosum, and Verticillium dahliae from spinach seed. Plant Disease 89:1305-1312.
  • 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.
  • Koike, S.T., Matheron, M.E., and du Toit, L.J. 2005. First report of leaf spot of spinach, caused by Stemphylium botryosum, in Arizona. Plant Disease 89:1209.
  • du Toit, L.J. 2004. Management of diseases of seed crops. Pages 675-677, In: Encyclopedia of Plant and Crop Sciences. R.M. Goodman, Editor. Marcel Dekker, NY.
  • du Toit, L.J., Derie, M.L., and Pelter, G.Q. 2004. Botrytis species in onion seed crops in Washington. Plant Disease 88:1061-1068.
  • du Toit, L.J., Glawe, D.A., and Pelter, G.Q. 2004. First report of powdery mildew of onion (Allium cepa) caused by Leveillula taurica in the Pacific Northwest. Online. Plant Health Progress doi:10.1049/PHP-2004-1129-01-HN.
  • du Toit, L.J., Pappu, H.R., Druffel, K.L., and Pelter, G.Q. 2004. Iris yellow spot virusin onion bulb and seed crops in Washington. Plant Disease 88:222.
  • 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.
  • du Toit, L.J., Inglis, D.A., and Pelter, G.Q. 2003. Fusarium proliferatum pathogenic on onion bulbs in Washington. Plant Disease 87:750.
  • du Toit, L.J., and Pelter, G.Q. 2003. Wilt of radish caused by Fusarium oxysporum f. sp. raphani in Washington State. Plant Health Progress doi:10.1094/PHP-2003-0616-01-HN.
  • Putnam, M.L., and du Toit, L.J. 2003. First report of Alternaria blight caused by Alternaria panax on ginseng (Panax quinquefolias L.) in Oregon and Washington, USA. New Disease Reports, British Society for Plant Pathology.
  • du Toit, L.J., Derie, M.L., Hsiang, T., and Pelter, G.Q. 2002. Botrytis porri in onion seed crops and onion seed. Plant Disease 86:1178.
  • du Toit, L.J., and Derie, M.L. 2001. Stemphylium botryosum pathogenic on spinach seed crops in Washington. Plant Disease 85:920.
  • Pataky, J.K., du Toit, L.J., and Freeman, N.D. 2000. Stewart’s wilt reaction of an international collection of Zea mays germplasm inoculated with Erwinia stewartii. Plant Disease 84:901-906.
  • du Toit, L.J., and Pataky, J.K. 1999. Effects of silk maturity and pollination on infection of maize ears by Ustilago maydis. Plant Disease 83:621-626.
  • du Toit, L.J., and Pataky, J.K. 1999. Variation associated with silk channel inoculation for common smut of sweet corn. Plant Disease 83:727-732.
  • du Toit, L.J., and Pataky, J.K. 1999. Reactions of processing sweet corn hybrids to Gibberella ear rot. Plant Disease 83:176-180.
  • du Toit, L.J., Kirby, H.W., and Pedersen, W.L. 1997. Evaluation of an aeroponics system to screen maize genotypes for resistance to Fusarium graminearum seedling blight. Plant Disease 81:175-179.


In 2010, Lindsey was assigned a 10% teaching appointment for co-teaching Field Plant Pathology (Pl P 525), which she then took full responsibility for teaching from 2012. The vegetable seed pathology program also provides funding and facilities for graduate student thesis or dissertation projects on vegetable diseases.

Professional Activities

Senior Editor for Plant Disease (2010-2012, 2013-2015)

Associate Editor for Agronomy Journal (2008-2011)

Associate Editor for Phytopathology (2010)

Associate Editor for Plant Disease (2000-2002)

Ad-hoc reviewer for >10 peer-reviewed journals and other publications of the American Phytopathological Society, Canadian Phytopathological Society, and other plant pathology, horticultural, and agronomic associations.

Positions Available

Accepting undergraduate and high school summer interns or time-slip assistants to work at the WSU-Mount Vernon NWREC. Student housing is available at this facility.  In 2020, there were five graduate students in the Vegetable Seed Pathology program: PhD students Alex Batson, Kayla Spawton, and Marilen Nampijja; MS student Ryan Solemslie; and MS in Ag student Stephanie Crane. Other members of the team include USDA NIFA SCRI Project Manager, Dr. Heather MacKay; Research Associate, Dr. Sanjaya Gyawali; Scientific Assistant Sr., Mike Derie; Agricultural Research Technologist II, Paul Morgan; and Time-slip Assistant, Eliza Mae Andrews.