TEMPLATE DESIGN © 2008 www.PosterPresentations.com • There were 3 cropping rotations in place at St. John: winter pea-winter wheat-spring wheat, cover crop- winter wheat-spring wheat, and fallow-winter wheat- spring wheat. These rotations were replicated so that every crop in each rotation was present in the field. This design was replicated 5 times in the same field. • Crops: winter wheat, spring wheat, winter pea, multi- species cover crop, and a fallow plot. • Sentinel seed station design: medium-sized Petri dish bottoms, filled with plasticine modeling clay with 20 seeds of each species pressed into the clay. • Closed treatment had 0.64 cm hardware mesh cage to exclude rodents and birds. Open treatment had no cage. • There were 4 sampling dates between July 5-Sep 26 2019 and the stations were left in the field for 7 days. • There were 20 replications of fallow, winter pea, and cover crop plots and 60 replications of winter wheat and spring wheat (n = 180). Seed Removal in Pacific Northwest Cereal Production Systems Jessica Kalin*, Sanford D. Eigenbrode* *Department of Entomology, Plant Pathology, and Nematology University of Idaho Introduction Methods Acknowledgements Research Objective: Test these four hypotheses using sentinel seed baits deployed into the replicated trial at St. John, WA. Results References • With projected changes in climate, Pacific Northwest growers are expected to modify their existing cereal- based cropping systems to more resilient, diversified systems. • Diversified systems include more crops, crop rotations, and cover cropping. • These cropping system modifications potentially increase vulnerability to weed and insect pests and this requires research. • Bromus tectorum (downy brome), Chenopodium album (common lambsquarters), and Anthemis cotula (Mayweed chamomile) are common weeds in the Pacific Northwest. [1-3] • “Landscapes in Transition” (LIT) is an inter-disciplinary, multi-institutional Coordinated Agricultural Project focuse on the development and adoption of sustainable and resilient cereal-based production systems in the Inland Pacific Northwest. • As part of LIT, we compared the removal rates by seed predators of these 3 weed species in 5 different crops in an ongoing replicated trial in St. John, WA. Plots at the field site in St. John, Washington. Seed trays placed ~1m apart. This study is part of a large collaborative project, Landscapes in Transition, funded through award #2017-68002-26819 from the National Institute of Food and Agriculture. Special thanks to Grace Overlie and Anna Stutz. Table 1. Partial ANOVA table with weed species, date, crop, treatment, and their interactions. Significant effects listed left. Highlighted effects are reported in detail here. Non-significant effects include: cage, weed species:cage, weed species:date:cage, and weed species:date:cage:crop. [1] Rydrych, D.J. 1974. Competition between winter wheat and downy brome. Weed Science, 22(3): 211-214. [2] Lyon, D.J., Burke, I.C., Hulting, A.G. & Campbell, J.M. 2017. Integrated management of mayweed chamomile in wheat and pulse crop production systems. Washington State University Extension Publications PNW695, pp 106. [3] Bohan, D.A., Boursault, A., Brooks, D.R., & Petit, S. 2011. National-scale regulation of the weed seedbank by carabid predators. Journal of Applied Ecology, 48: 888-898. **All photographs taken by Jessica Kalin unless stated otherwise. • The effects of weed species and crop were significant. The interaction between these effects (p < 0.01) is due to the low rates of lambsquarters seed removal compared to Mayweed and downy brome, especially in fallow. • Removal rates did not differ between open and closed stations (“cage” effect); the cage x crop interaction (p < 0.001) reflects the higher removal rates from caged stations in fallow and cover crop plots than in other crops. This was most evident on week 2 (wk2), accounting for the three-way interaction including date. • Removal of lambsquarte