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Abstract: Methyl salicylate (MeSA), a herbivore-induced plant volatile, can elicit control of pests through attraction of beneficial arthropods. This study evaluates the effect of synthetic MeSA lures (PredaLure) on arthropod populations during the 2009 and 2010 seasons in two Oregon vineyards (Dayton and Salem). MeSA lures were deployed at a low (4/plot or 260 lures/ha) and high (8/plot or 520 lures/ha) rate in ∼152m2 plots while control plots contained no lure. The predatory mite Typhlodromus pyri Scheuten is considered to be a key biological control agent of the grapevine rust mite, Calepitrimerus vitis Nalepa in Oregon vineyards. Leaf samples were collected to assess T. pyri, C. vitis, spider mite (Tetranychidae) and thrips (Thripidae) population densities in MeSA treated plots compared to control plots. Yellow sticky traps were used to monitor other key predator groups including Anthocoridae, Araneae, Coccinellidae and Syrphidae. Our data did not display consistent trends in T. pyri response to MeSA between treatments at the two field sites over two seasons. Mean seasonal coccinellid counts were significantly higher in MeSA treatments in both years at Dayton. No differences in C. vitis population densities were found between treatments in both years. In 2009 at Salem, significantly lower pest thrips densities occurred in low rate MeSA treatments in the latter part of the season although no trend of decreased seasonal abundance was evident. [Copyright &y& Elsevier]

• Irrigation system height did not significantly influence surface soil moisture content. • Irrigation system height did significantly influence surface soil moisture isotope ratios. • Low elevation, as compared to traditional, center pivot irrigation had reduced evaporation. The arid areas east of the Cascade Mountains in the Pacific Northwest have high irrigation water use and changing the elevation of sprinkler nozzles in these systems has been proposed as a strategy to reduce evaporative losses in order to diminish the total irrigation water demand. Validation of any structural modifications requires techniques able to identify water losses from these systems that were non-productive, particularly soil evaporation. In this study, we quantified evaporation losses from soils under Mid Elevation Spray Application (MESA) and Low Elevation Spray Application (LESA) irrigation systems by using stable isotope tracers to estimate the fraction of non-productive water losses (i.e. the ratio of soil water evaporation to irrigation water applied, E / I). During mid-summer 2017 in eastern Oregon and southeast Washington, we collected soil samples at multiple positions and depths around the central irrigation tower from four different agricultural fields, each with both LESA and MESA configurations. We measured the hydrogen and oxygen stable isotope ratio of soil water at MESA and LESA field locations using H 2 O liquid – H 2 O vapor equilibration laser spectroscopy. Though soil moisture contents were similar, the average isotope ratio of soil water under LESA irrigation (δ D = −114.5‰, δ18O = −14.5‰) had lower values than under MESA irrigation (δ D = −108.2‰, δ18O = −13.1‰). Calculated E / I values demonstrated higher sprinkler and soil water evaporation occurring at the MESA irrigated locations (E / I = 16.1%) compared to the LESA irrigated locations (E / I = 9.0%). We find that LESA systems have lower non-productive water losses than MESA systems and are thereby more efficient users of applied water. Our results suggest that stable water isotopes provide a technique for improving the management of water resources through the assessment of irrigation efficiency. [ABSTRACT FROM AUTHOR]