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Dr. Lindsey du Toit

Research Highlight

Faculty Web Page

Vegetable Seed Pathology Program

Did you know that farmers in the PNW produce a significant percentage of the US and world supply of seed for >35 small-seeded vegetable crops? Although these high value seed crops total <15,000 acres annually in Washington, they play an important role in the global vegetable industry. One acre of hybrid cabbage seed crop produces about 2,000 lb of seed, which will plant about 10,000 acres of cabbage. About 90 countries import vegetable seed from the PNW because so few regions of the world have the specific climatic conditions necessary for production of high quality seed. The competitive nature of the vegetable seed industry means that growers must produce high quality seed that is pathogen-free.

The Vegetable Seed Pathology program was initiated in August 2000 by Lindsey du Toit at the WSU Mount Vernon NWREC, as part of the WSU Safe Food Initiative. The objective of this research and extension program is to contribute towards a sustainable and secure food supply by providing research and extension support on vegetable seed crop diseases regionally, nationally, and internationally. Lindsey’s program investigates the biology, epidemiology, and management of an array of fungal, viral, and bacterial diseases that affect small-seeded vegetable seed crops in the Pacific Northwest.

Several research projects on which the program has focused in the past 6 years include:

The Vegetable Seed Pathology program collaborates widely with other researchers, extension specialists, and extension educators. Extension activities are accomplished through various workshops, conferences, publications, regional and state advisory committees, and the WSU Vegetable Pathology Team. A number of new diseases have been reported in WA and the USA by the Vegetable Seed Pathology program. For example, Fusarium wilt of radish in Washington (see PDF file) , the powdery mildew fungus Leveillula taurica on onion in Washington and on potato in the USA (see PDF file onion (pdf)potato (pdf)), Xanthomonas campestris pv. coriandri on coriander in the USA, Iris yellow spot virus (IYSV) on onion in Washington, Stemphylium leaf spot of spinach in Washington and Arizona, and infection of onion seed crops and onion seed by Botrytis porri.

Working with Lindsey are two skilled Ag. Research Technologists, Mike Derie and Louise Brissey. Mike has >20 years of experience in applied seed pathology. Louise provides support for greenhouse trials and seed assays. Pablo Hernandez-Perez completed his MS program in the Vegetable Seed Pathology program in spring 2005, with his thesis on seedborne aspects of leaf spot diseases in spinach seed crops. In 2005, Jaime Cummings started an MS program in this program to investigate the potential efficacy of organic seed treatments for control of damping-off pathogens of spinach. Martin Chilvers completed a 1-year postdoctorate position in the Vegetable Seed Pathology program, investigating development of a molecular seed assay for Botrytis spp. causing neck rot of onion. Leigh Ann Harrison will start a PhD program with Lindsey in fall 2006, evaluating the management of Fusarium wilt in spinach seed production. Lindsey’s program also houses undergraduate interns, e.g., Michael Picha (from WSU) and Blair Baber (from Western Washington University).

The Vegetable Seed Pathology program is well supported by seed growers in Washington (the Columbia Basin Vegetable Seed Association and the Puget Sound Seed Growers’ Association), state and federal grants, the Alfred Christianson Endowed Professorship, and the Robert MacDonald Vegetable Seed Memorial Fund.

Mike, Martin, and Lindsey du Toit

Rows of cabbage in bloom with the text cabbage seed crop trial in bloom

Carrot umbel with the text carrot umbel severely blighted by Xanthomonas campestris pv. carotae

A close up of a spinach seed with the text Pseudothecia of Pleospora herbarum (teleomorph of Stemphylium botryosum) developing on a spinach seed

A group photo with the text Vegetable Seed Pathology support staff. Front (L-R): Louise Brissey (Ag. Research Tech II), Barbara Holmes (time-slip assistant), & Jaime Cummings (MS student). Back (L-R): Nathan Lloyd (Humbolt State University undergraduate) and Blair Baber (Western Washington University biology intern).