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Plants growing with plastic mulches in a high tunnel at the WSU Mount Vernon Northwest Research and Extension Center. (Photo by Carol Miles, WSU)

MOUNT VERNON, Wash. – For the first time, tomato growers using high tunnels (low-cost greenhouses, http://mtvernon.wsu.edu/hightunnels/) in western Washington can manage one of the most serious plant diseases organically, said plant pathologist Debra Inglis.

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A tomato plant with late blight. (Photo by Debra Inglis, WSU)

Insight into late blight management in organic agriculture is one of the many outcomes of a three-year project led by Washington State University. A team of 17 scientists tested five biodegradable mulches – alternatives to the traditional plastic mulch covers that suppress weeds, maintain soil temperatures, increase plant production and shorten harvest time – in open fields and increasingly popular high tunnels.

Production and disposal of plastic mulch, which is used to enhance the growth of several hundred thousand acres of specialty crops in the United States, pose environmental and financial challenges to growers who need to find a way to recycle the material.

Inglis-D-2009-80WSU researchers Inglis and Carol Miles led the U.S. Department of Agriculture National Institute of Food and Agriculture (NIFA) Specialty Crops Research Initiative (SCRI) project. Their leadership earned them the 2013 NIFA Partnership Award for Innovative Programs and Projects, which they accepted in Washington, D.C. on behalf of their SCRI team in November. Team members across six institutions Miles-C-2012-80conducted trials with biodegradable mulches in high tunnels in Texas, Tennessee and Washington.

“We found that high tunnels can produce higher tomato, lettuce and strawberry yields relative to the open fields in the three field study regions,” Inglis said. “Higher crop yield can translate to increases in profitability depending on the crop’s production costs and market price.”

The higher temperatures, better ventilation, lower humidity and reduced leaf wetness inside the high tunnels also help combat the water mold that spreads late blight infection to tomatoes.

The diverse research team included economists, horticulturists, plant pathologists, sociologists, biological systems engineers and soils and textile scientists. Looking at the relationships between five different types of mulches in the high tunnels, the project used the expertise of textile scientists from the WSU Department of Apparel, Merchandising, Design and Textiles (AMDT). They tested for key changes in the mulches over time, including changes in weight, thickness, flexibility, pore size and color.

Scot Hulbert, interim chair of the WSU Department of Plant Pathology, noted that the “NIFA is now the chief institute in the country funding agricultural research and this (award) means they recognize that we are doing it right.”

Inglis said she and Miles are honored to receive the award and grateful to each of their team members – including Tom Marsh and Suzette Galinato in economic sciences, Jessica Goldberger in crop and soil sciences, and Hang Liu in AMDT – as well as former graduate students Jeremy Cowan and Marianne Powell.

For details and year-by-year reports on the project, visit: http://mtvernon.wsu.edu/hightunnels/. For a quick look inside a few Washington state organic growers’ high tunnels from the 2013 Tilth Conference, see http://on.fb.me/HN1nNo.

 

Contacts:

Debra Inglis, WSU plant pathologist, 360-848-6134, dainglis@wsu.edu

Rachel Webber, WSU CAHNRS Communications, 509-335-0837, rcwebber@wsu.edu