2012 Dryland Field Day Abstracts - Dept. of Crop and Soil Sciences ...

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2012 Field Day Abstracts: Highlights of Research Progress
Soilborne wheat mosaic (SBWM) is a new problem for Washington wheat growers having been first recognized in 2008 in the Walla
Walla area. This disease is caused by a virus that is transmitted by a fungal-like organism that lives in soil. Roots are infected in the
fall and symptoms appear in early spring. Because the virus lives in soil, the disease occurs in the same spots within fields each year
and can be moved with soil on farm implements, shoes, or tires. The problem appears limited to the Walla Walla area at the
current time, but we have been collaborating with scientists from Oregon State University to screen PNW wheat varieties for
resistance. A few varieties from the PNW have some resistance, with the hard red winter wheats having the best resistance as a
class.
Results of our field test data are available online at the WSU Variety testing website (http://variety.wsu.edu) and Plant Disease
Management Reports (http://www.plantmanagementnetwork.org/pub/trial/PDMR/reports/2012). This research is part of our long
-term goal to improve resistance of winter wheat varieties to these important diseases and thereby reduce yield losses for
Washington State wheat growers.
Molecular Diagnostics for Plant-Parasitic Nematodes in the Pacific Northwest
Patricia Okubara 1 , Guiping Yan 2 and Richard Smiley 2
1 USDA-ARS, Root Disease and Biological Control Research Unit, Pullman; 2 Columbia Basin Agricultural Research Center,
OSU, Pendleton, OR
Plant-parasitic nematodes affect the health and yields of wheat, barley and other crops of Pacific Northwest (PNW). The root-lesion
nematodes Pratylenchus thornei and P. neglectus are estimated to cause $51 million losses to the wheat industry each year. Crops
used in rotation with wheat, including pea, chickpea, lentil, canola and mustard, are
also susceptible to root-lesion nematodes. The cereal cyst nematodes Heterodera
avenae and H. filipjevi pose additional threats to wheat and barley production,
causing estimated annual losses of at least $3.4 million. We have developed rapid,
sensitive and specific conventional and real-time PCR assays for P. thornei, P.
neglectus, and H. filipjevi in PNW soils. Conventional PCR assays detect 60 and 150 P.
thornei and P. neglectus juveniles per pound of soil, respectively, well below the
calculated economic threshold of 1,000 juveniles per pound of soil. Our real-time
PCR assay for P. thornei detects 450 juveniles per pound and correlates well (r 2 =0.76)
to the conventional extraction and counting method. The molecular diagnostic
assays circumvent time-consuming quantification and microscopic examination of
the nematodes, thereby facilitating surveys and management assessments. Realtime
PCR assays for P. neglectus and H. avenae are being developed.
Top: Guiping Yan conducting real-time
PCR assays. Left: Micrographs of the
nematodes
Anomalous Armyworm Infestations in Eastern Washington and Oregon Wheat Implicate Dargida
spp. plus other Noctuids
Diana Roberts, WSU Extension, Spokane, WA; Peter Landolt, USDA-ARS, Yakima, WA; Mary Corp, OSU Extension, Pendleton,
OR; and Silvia Rondon, OSU, Hermiston, OR
Unusual, armyworm-type damage to wheat and barley crops in Lincoln County, WA, and Umatilla County, OR, in 2007 and 2008
prompted concern and further investigation. Damage in each county was restricted to areas about 20 miles in diameter.
Universal Moth Traps baited with an armyworm sex attractant (pheromone) were effective in trapping male moths. Traps located
across the cereal-producing counties of eastern Washington in 2009 and 2010, and Umatilla County, OR, in 2010 and 2011,
confirmed the presence of the original suspect, the wheat head armyworm Dargida diffusa (Walker). However, the native species
Dargida terrapictalis (Buckett) was the predominant Noctuid moth captured.