Rush skeletonweed management in Pacific Northwest winter wheat-fallow cropping systems

Rattail fescue infestations are increasing in dryland conservation-tillage winter wheat cropping systems in the inland Pacific Northwest (PNW) region of Idaho, Oregon, and Washington. Rattail fescue typically is controlled with cultivation in conventional tillage farming systems. However, reduced soil disturbance has allowed infestations to increase significantly. The objectives of this research were to determine the effectiveness of glyphosate rates and application timings on control of rattail fescue during a chemical-fallow period in winter wheat cropping systems. Chemical-fallow field studies were conducted during two growing seasons at nine sites throughout the PNW. Glyphosate was applied early POST, late POST, or sequentially in early plus late POST timings. Additionally, paraquat + diuron was applied early and late POST alone or sequentially with glyphosate. Sequential application treatments (glyphosate followed by [fb] glyphosate, paraquat + diuron fb glyphosate, and glyphosate fb paraquat + diuron) controlled rattail fescue (∼ 94% in Idaho and Washington, ∼ 74% in Oregon) and reduced panicle number (∼ 85% in Idaho, ∼ 30% in Oregon and Washington) equivalent to or greater than one-time treatments. Rattail fescue control and panicle reduction generally increased with increasing rates of glyphosate within application timings. Paraquat + diuron usually provided similar control and reduced rattail fescue panicle number compared to glyphosate treatments applied at the same application timing. Although not completely effective, sequential applications of either glyphosate or paraquat + diuron, fb glyphosate will provide effective control during chemical fallow.

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Scouringrush (Equisetum spp.) control in dryland winter wheat

Weed Technology ◽

10.1017/wet.2019.45 ◽

2019 ◽

Vol 33 (6) ◽

pp. 808-814

Author(s):

Blake D. Kerbs ◽

Andrew G. Hulting ◽

Drew J. Lyon

Keyword(s):

Species Composition ◽

Winter Wheat ◽

Pacific Northwest ◽

Field Experiments ◽

Cropping Systems ◽

Yield Response ◽

Herbicide Application ◽

Weed Species ◽

Herbicide Treatments ◽

Chemical Fallow

AbstractThe adoption of chemical fallow rotations in Pacific Northwest dryland winter wheat production has caused a weed species composition shift in which scouringrush has established in production fields. Thus, there has been interest in identifying herbicides that effectively control scouringrush in winter wheat–chemical fallow cropping systems. Field experiments were established in growers’ fields near Reardan, WA, in 2014, and The Dalles, OR, in 2015. Ten herbicide treatments were applied to mowed and nonmowed plots during chemical fallow rotations. Scouringrush stem densities were quantified the following spring and after wheat harvest at both locations. Chlorsulfuron plus MCPA-ester resulted in nearly 100% control of scouringrush through wheat harvest. Before herbicide application, mowing had no effect on herbicide efficacy. We conclude chlorsulfuron plus MCPA-ester is a commercially acceptable treatment for smooth and intermediate scouringrush control in winter wheat–chemical fallow cropping systems; however, the lack of a positive yield response when scouringrushes were controlled should factor into management decisions.

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Weed Management for Crop Production in the Northwest Wheat (Triticum aestivum) Region

Weed Science ◽

10.1017/s0043174500094133 ◽

1996 ◽

Vol 44 (2) ◽

pp. 429-436 ◽

Cited By ~ 15

Author(s):

Frank L. Young ◽

Alex G. Ogg ◽

Donn C. Thill ◽

Douglas L. Young ◽

Robert I. Papendick

Keyword(s):

Winter Wheat ◽

Pacific Northwest ◽

Weed Management ◽

Crop Production ◽

Conservation Tillage ◽

Cropping Systems ◽

Wild Oat ◽

Downy Brome ◽

Tillage Systems ◽

The Pacific

A 9-yr large-scale integrated pest management (IPM) study was initiated in 1985 to develop and refine profitable conservation cropping systems in the Palouse wheat-growing region of the Pacific Northwest. Weed scientists from the USDA-ARS and the land-grant universities of ID and WA led a team of researchers and extension personnel from eight disciplines to investigate the interactions of crop systems, tillage systems, and weed management levels (WML) on crop production. Ineffective weed control has been a major deterrent to the adoption of conservation tillage by wheat growers. With this in mind, the primary focus of the scientists on the IPM project was integrated weed management (IWM) in conservation crop production systems for highly erodible land. For the first time in the Pacific Northwest, systems research developed a conservation production system using a 3-yr crop rotation that controlled weeds effectively, reduced erosion, was less risky than traditional farming systems, and was profitable. Broadleaf weeds were more prevalent in the 3-yr rotation of winter wheat-spring barley-spring pea compared to continuous wheat in both conservation and conventional tillage systems. In conservation tillage, troublesome grass weeds included wild oat and downy brome. Wild oat was controlled effectively at the moderate and maximum weed management levels under conservation tillage in the 3-yr rotation. Two years out of winter wheat (such as in the 3-yr rotation) reduced downy brome populations. In contrast, growing a spring crop 1 yr, followed by 2 yr of winter wheat was not effective for controlling downy brome. Effective weed control was instrumental in developing successful conservation IPM cropping systems, and education and technology transfer were important in helping action agencies assist growers in adopting these systems.

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Integrated Weed Management Systems Identified for Jointed Goatgrass (Aegilops cylindrica) in the Pacific Northwest

Weed Technology ◽

10.1614/wt-d-10-00046.1 ◽

2010 ◽

Vol 24 (4) ◽

pp. 430-439 ◽

Cited By ~ 8

Author(s):

Frank L. Young ◽

Daniel A. Ball ◽

Donn C. Thill ◽

J. Richard Alldredge ◽

Alex G. Ogg ◽

...

Keyword(s):

Winter Wheat ◽

Pacific Northwest ◽

Weed Management ◽

Cropping Systems ◽

Wheat Variety ◽

Integrated Weed Management ◽

Weed Density ◽

Jointed Goatgrass ◽

F Region ◽

The Pacific

Jointed goatgrass is an invasive winter annual grass weed that is a particular problem in the low to intermediate rainfall zones of the Pacific Northwest (PNW). For the most part, single-component research has been the focus of previous jointed goatgrass studies. In 1996, an integrated cropping systems study for the management of jointed goatgrass was initiated in Washington, Idaho, and Oregon in the traditional winter wheat (WW)–fallow (F) region of the PNW. The study evaluated eight integrated weed management (IWM) systems that included combinations of either a one-time stubble burn (B) or a no-burn (NB) treatment, a rotation of either WW–F–WW or spring wheat (SW)–F–WW, and either a standard (S) or an integrated (I) practice of planting winter wheat. This study is the first, to our knowledge, to evaluate and identify complete IWM systems for jointed goatgrass control in winter wheat. At the Idaho location, in a very low weed density, no IWM system was identified that consistently had the highest yield, reduced grain dockage, and reduced weed densities. However, successful IWM systems for jointed goatgrass management were identified as weed populations increased. At the Washington location, in a moderate population of jointed goatgrass, the best IWM system based on the above responses was the B:SW–F–WW:S system. At the Washington site, this system was better than the integrated planting system because the competitive winter wheat variety did not perform well in drought conditions during the second year of winter wheat. At the Oregon site, a location with a high weed density, the system B:SW–F–WW:I produced consistently higher grain yields, reduced grain dockage, and reduced jointed goatgrass densities. These integrated systems, if adopted by PNW growers in the wheat–fallow area, would increase farm profits by decreasing dockage, decreasing farm inputs, and reducing herbicide resistance in jointed goatgrass.

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Pratylenchus neglectus Reduces Yield of Winter Wheat in Dryland Cropping Systems

Plant Disease ◽

10.1094/pdis-93-3-0263 ◽

2009 ◽

Vol 93 (3) ◽

pp. 263-271 ◽

Cited By ~ 36

Author(s):

Richard W. Smiley ◽

Stephen Machado

Keyword(s):

Winter Wheat ◽

Pacific Northwest ◽

Cropping Systems ◽

Spring Barley ◽

Wheat Yield ◽

Pratylenchus Neglectus ◽

Winter Wheat Yield ◽

Chemical Fallow ◽

Root Lesion Nematodes ◽

Increasing Trends

Wheat (Triticum aestivum) in low-precipitation regions of eastern Oregon and Washington is grown mostly as rainfed biennial winter wheat (10-month growing season) planted into cultivated fallow (14-month crop-free period). There are increasing trends for cultivated fallow to be replaced by chemical fallow and for spring cereals to be planted annually without tillage. Most fields are infested by the root-lesion nematodes Pratylenchus neglectus or P. thornei. A replicated multiyear experiment was conducted to compare cropping systems on soil infested by P. neglectus. Populations became greater with increasing frequency of the host crops mustard, pea, and wheat. Annual winter wheat had the highest P. neglectus populations, the lowest capacity to extract soil water, and a lower grain yield compared with wheat grown biennially or rotated with other crops. Populations of P. neglectus did not differ for cultivated versus chemical fallow. Lowest populations occurred in annual spring barley. Winter wheat yield was inversely correlated with the population of P. neglectus. Measures to monitor and to reduce the population of P. neglectus in Pacific Northwest wheat fields are recommended.

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Management of Italian Ryegrass (Lolium perennessp.multiflorum) in Western Oregon with Preemergence Applications of Pyroxasulfone in Winter Wheat

Weed Technology ◽

10.1614/wt-d-11-00059.1 ◽

2012 ◽

Vol 26 (2) ◽

pp. 230-235 ◽

Cited By ~ 23

Author(s):

Andrew G. Hulting ◽

Joseph T. Dauer ◽

Barbara Hinds-Cook ◽

Daniel Curtis ◽

Rebecca M. Koepke-Hill ◽

...

Keyword(s):

Winter Wheat ◽

Pacific Northwest ◽

Field Experiments ◽

Cropping Systems ◽

Wheat Yield ◽

The United States ◽

Italian Ryegrass ◽

Weed Species ◽

Application Rates ◽

Grass Weed

Management of Italian ryegrass in cereal-based cropping systems continues to be a major production constraint in areas of the United States, including the soft white winter wheat producing regions of the Pacific Northwest. Pyroxasulfone is a soil-applied herbicide with the potential to control broadleaf and grass weed species, including grass weed biotypes resistant to group 1, 2, and 7 herbicides, in several crops for which registration has been completed or is pending, including wheat, corn, sunflower, dry bean, and soybean. Field experiments were conducted from 2006 through 2009 near Corvallis, OR, to evaluate the potential for Italian ryegrass control in winter wheat with applications of pyroxasulfone. Application rates of PRE treatments ranged from 0.05 to 0.15 kg ai ha−1. All treatments were compared to standard Italian ryegrass soil-applied herbicides used in winter wheat, including diuron, flufenacet, and flufenacet + metribuzin. Visual evaluations of Italian ryegrass and ivyleaf speedwell control and winter wheat injury were made at regular intervals following applications. Winter wheat yields were quantified at grain maturity. Ivyleaf speedwell control was variable, and Italian ryegrass control following pyroxasulfone applications ranged from 65 to 100% and was equal to control achieved with flufenacet and flufenacet + metribuzin treatments and greater than that achieved with diuron applications. Winter wheat injury from pyroxasulfone ranged from 0 to 8% and was most associated with the 0.15–kg ha−1application rate. However, this early-season injury did not negatively impact winter wheat yield. Pyroxasulfone applied at the application rates and timings in these studies resulted in high levels of activity on Italian ryegrass and excellent winter wheat safety. Based on the results, pyroxasulfone has the potential to be used as a soil-applied herbicide in winter wheat for Italian ryegrass management and its utility for management of other important grass and broadleaf weeds of cereal-based cropping systems should be evaluated.

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Effects of Crop Rotations and Tillage on Pratylenchus spp. in the Semiarid Pacific Northwest United States

Plant Disease ◽

10.1094/pdis-08-12-0788-re ◽

2013 ◽

Vol 97 (4) ◽

pp. 537-546 ◽

Cited By ~ 19

Author(s):

Richard W. Smiley ◽

Stephen Machado ◽

Jennifer A. Gourlie ◽

Larry C. Pritchett ◽

Guiping Yan ◽

...

Keyword(s):

Winter Wheat ◽

Pacific Northwest ◽

Spring Wheat ◽

Cropping Systems ◽

Spring Barley ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

The Pacific ◽

Spring Cereals ◽

Chemical Fallow

There is interest in converting rainfed cropping systems in the Pacific Northwest from a 2-year rotation of winter wheat and cultivated fallow to direct-seed (no-till) systems that include chemical fallow, spring cereals, and food legume and brassica crops. Little information is available regarding effects of these changes on plant-parasitic nematodes. Eight cropping systems in a low-precipitation region (<330 mm) were compared over 9 years. Each phase of each rotation occurred each year. The density of Pratylenchus spp. was greater in cultivated than chemical fallow, became greater with increasing frequency of host crops, and was inversely associated with precipitation (R2 = 0.92, α < 0.01). Densities after harvesting mustard, spring wheat, winter wheat, and winter pea were greater (α < 0.01) than after harvesting spring barley or spring pea. Camelina also produced low densities. Winter wheat led to a greater density of Pratylenchus neglectus and spring wheat led to a greater density of P. thornei. Density of Pratylenchus spp. was correlated (R2 = 0.88, α < 0.01) but generally higher when detected by real-time polymerase chain reaction on DNA extracts from soil than when detected by a traditional method. Selection of different Pratylenchus spp. by different wheat cultivars or growth habit must be addressed to minimize the level of nematode risk to future plantings of intolerant crops.

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Rush skeletonweed (Chondrilla juncea L.) control in fallow

Weed Technology ◽

10.1017/wet.2021.79 ◽

2021 ◽

pp. 1-22

Author(s):

Mark E. Thorne ◽

Drew J. Lyon

Keyword(s):

Winter Wheat ◽

Pacific Northwest ◽

Plant Density ◽

Wheat Yield ◽

Field Research ◽

Effective Control ◽

Invasive Weed ◽

Complete Control ◽

Rush Skeletonweed

Rush skeletonweed is an invasive weed in winter wheat (WW)/summer fallow (SF) rotations of the low to intermediate rainfall areas of the inland Pacific Northwest. Standard weed control practices are not effective, resulting in additional SF tillage or herbicide applications. The objective of this field research was to identify herbicide treatments that control rush skeletonweed during the SF phase of the WW/SF rotation. Trials were conducted near LaCrosse, WA in 2017-2019 and 2018-2020, and near Hay, WA in 2018-2020. The LaCrosse 2017-2020 trial was in tilled SF; the other two trials were in no-till SF. Fall post-harvest applications in October included clopyralid, clopyralid plus 2,4-D, clopyralid plus 2,4-D plus chlorsulfuron plus metsulfuron, aminopyralid, picloram, and glyphosate plus 2,4-D. Spring treatments of clopyralid, aminopyralid, and glyphosate were applied to rush skeletonweed rosettes. Summer treatments of 2,4-D were applied when rush skeletonweed initiated bolting. Plant density was monitored through the SF phase in all plots. Picloram provided complete control of rush skeletonweed through June at all three locations. Fall-applied clopyralid, clopyralid plus 2,4-D, and clopyralid followed by 2,4-D in summer reduced rush skeletonweed through June at the two LaCrosse sites but were ineffective at Hay. In August, just prior to winter wheat seeding, the greatest reductions in rush skeletonweed density were achieved with picloram and fall-applied clopyralid at the two LaCrosse sites. No treatments provided effective control into August at Hay. Wheat yield in the next crop compared to the nontreated control was reduced only at one LaCrosse site by a spring-applied aminopyralid treatment, otherwise no other reductions were found. Long-term control of rush skeletonweed in WW/SF may be achieved by a combination of fall application of picloram, after wheat harvest, followed by an effective burn-down treatment in August prior to winter wheat seeding.

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Rush Skeletonweed (Chondrilla juncea) Control in Pacific Northwest Winter Wheat

Weed Technology ◽

10.1017/wet.2018.17 ◽

2018 ◽

Vol 32 (4) ◽

pp. 360-363 ◽

Cited By ~ 1

Author(s):

John F. Spring ◽

Mark E. Thorne ◽

Ian C. Burke ◽

Drew J. Lyon

Keyword(s):

Winter Wheat ◽

Pacific Northwest ◽

Field Studies ◽

Visual Control ◽

Wheat Production ◽

Effective Option ◽

Auxin Herbicides ◽

Eastern Washington ◽

Rush Skeletonweed ◽

Chondrilla Juncea

AbstractRush skeletonweed is emerging as a regionally important weed of winter wheat production in eastern Washington. Field studies were conducted during the 2016 and 2017 crop years to evaluate several auxin herbicides applied at two seasonal timings (fall or spring) for control of rush skeletonweed in winter wheat. Clopyralid (210 g ae ha-1) provided>90% visual control of rush skeletonweed in both years of the study and aminopyralid (10 g ae ha-1) provided>80% visual control. Aminocyclopyrachlor, dicamba, and 2,4-D provided<55% control of rush skeletonweed. Season of application did not meaningfully affect efficacy of any herbicide tested. Wheat yields were reduced by 39 to 69% compared to the non-treated check when aminocyclopyrachlor was applied in the spring. Clopyralid is an effective option for control of rush skeletonweed in Pacific Northwest winter wheat.

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Simulated effects of CO2and warming on cereal leaf beetle (Oulema melanopus) induced crop loss on winter wheat in the Pacific Northwest USA

10.1603/ice.2016.115482 ◽

2016 ◽

Author(s):

Byju N. Govindan

Keyword(s):

Winter Wheat ◽

Pacific Northwest ◽

Leaf Beetle ◽

Crop Loss ◽

Cereal Leaf Beetle ◽

Oulema Melanopus ◽

The Pacific

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