Project Title: Impact and Management of Plant-Parasitic Nematodes in Washington Wine Grape Vineyards
Project Duration: FY15, FY16, and FY17 (July 2014-Jun 2017 – 1 yr no-cost extension until
Jun 2018)

Principal Investigator(s): Michelle Moyer, Assistant Professor
Organization: WSU-IAREC, 24106 N. Bunn Rd., Prosser, WA 99350
Telephone: 509-786-9234

Co-PI(s): Inga Zasada and R. Paul Schreiner
Organization: USDA-ARS, HCRU, 3420 NW Orchard Ave., Corvallis, OR 97330
Telephone: 541-738-4051; 541-738-4095

Cooperator(s): Julie Tarara, Mimi Nye, Kari Smanse, and Joe Cotta
Organization: Ste Michelle Wine Estates
Description of Participation: Contacts for where the research trials relating to degree day modeling, rootstock evaluations, and nematicide trials are held.

Cooperator(s): Rick Hamman
Organization: Hogue Ranches/Mercer Estates Winery
Description of Participation: Contact for where research trials relating to degree day modeling are held.

Cooperator(s): Richard Hoff
Organization: Mercer Canyon
Description of Participation: Contact for where research trials relating to degree day modeling and nematicide trials are held.

Project Summary:

Very little is known about the impact of plant-parasitic nematodes on grapevines in Washington. Considering that Washington State is the second largest wine grape producer in the U.S. with a $154 million wine industry in 2009 (USDA, 2010), and knowing that plant-parasitic nematodes are important pests in other grape-producing regions, this is an area of concern for the industry. Washington grape growers lack the basic information regarding plant-parasitic nematodes required to make informed pre-and post-plant management decisions. This void in knowledge comes at a time when growers are interested in being part of sustainable production programs and when pre-plant soil fumigation is becoming more regulated.

All studies occurred in commercial vineyards. 1) A rootstock trial was planted in a site that had both fumigated and non-fumigated sections, so we can monitor how effective both fumigation and rootstocks are at keeping nematode population densities low. 2) Other commercial sites with known nematode populations were routinely sampled throughout the year to determine when the infective stage (second-stage juvenile; J2) of Northern Root-knot Nematode (Meloidogyne hapla) was present. A similar model for Meloidygne chitwoodi exists for potatoes in Washington (Pinkerton et al. 1991). The threshold temperature for development of M. hapla is 10° C (Tyler 1933), indicating that a typical degree-day calculation with a 10° C base could be used to determine nematode generation time. Root growth data was also collected at these sites to determine if the timing of root flushes in grapevine influence nematode population development. 3) Finally, sites with known nematode populations were also included in a post-planting nematicide evaluation trial, to determine the effectiveness of different, new products that are making their way to the market. Effectiveness is determined by a reduction in nematode numbers or an increase in yield or vine vigor.

From a management perspective, knowing when J2 will be abundant in soil will be key since this is the life stage that is the easiest to target with nematicides or other potential control options. The developmental model that we will create will provide information as to when this life stage occurs, and thus, when post-plant nematicide applications may be most effective. We have designed a suite of experiments to evaluate the post-plant nematicides/insecticides and to monitor M. hapla development in grapevines. This information is essential in order to make appropriate recommendations and ensure that growers are getting the most for their money.

Read more by downloading the full report above.

Pest & Disease // Rootstocks // Viticulture //