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

Plant Disease ◽  
2013 ◽  
Vol 97 (4) ◽  
pp. 537-546 ◽  
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.

scholarly journals Pratylenchus neglectus Reduces Yield of Winter Wheat in Dryland Cropping Systems

Plant Disease ◽  
2009 ◽  
Vol 93 (3) ◽  
pp. 263-271 ◽  
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.

scholarly journals Virulence of Rhizoctonia oryzae on Wheat and Barley Cultivars from the Pacific Northwest

Plant Disease ◽  
2003 ◽  
Vol 87 (1) ◽  
pp. 51-55 ◽  
Author(s):  
T. C. Paulitz ◽  
J. D. Smith ◽  
K. K. Kidwell
Keyword(s):  
Winter Wheat ◽  
Pacific Northwest ◽  
Spring Wheat ◽  
Spring Barley ◽  
Root Diameter ◽  
Natural Soil ◽  
Root Tips ◽  
Barley Cultivars ◽  
Rhizoctonia Oryzae ◽  
Waitea Circinata

Rhizoctonia oryzae (teleomorph = Waitea circinata) causes sheath spot of rice and root rot of wheat and barley. R. oryzae commonly is isolated from barley, wheat, and pea plants in eastern Washington and Idaho. Eight representative isolates were tested for virulence on spring barley (Hordeum vulgare cv. Baronesse), soft white winter wheat (Triticum aestivum cv. Madsen), and hard red spring wheat (cv. Scarlet) planted in natural soil in the greenhouse and maintained at 16°C. All isolates caused significant reduction of emergence in barley, but only seven of the eight isolates and one of the eight isolates reduced emergence of winter wheat and spring wheat, respectively. All isolates caused significant stunting and reduction in the number of seminal roots, root length, and number of root tips on wheat and barley. Some isolates also reduced the frequency of fine secondary roots, resulting in a reduction of the average root diameter. Spring barley was more susceptible to R. oryzae than winter or spring wheat. The main effects of both cultivar and isolate were significant, and there was a significant isolate-cultivar interaction. R. oryzae isolate 80042 was the most virulent on barley, whereas R. oryzae isolate 801387 was the most virulent on wheat. The two isolates from pea were intermediate in virulence on wheat and barley. When screening germ plasm for potential resistance, isolates exhibiting the maximum virulence for each host should be used.

Nitrogen Fertility and Weed Management Critical for Continuous No-Till Wheat in the Pacific Northwest

2006 ◽  
Vol 20 (3) ◽  
pp. 658-669 ◽  
Author(s):  
Frank L. Young ◽  
Mark E. Thorne ◽  
Douglas L. Young
Keyword(s):  
Winter Wheat ◽  
Pacific Northwest ◽  
Crop Yield ◽  
Spring Wheat ◽  
Weed Management ◽  
Weed Density ◽  
N Level ◽  
No Till ◽  
The Pacific ◽  
Density And Biomass

No-till cropping is an option for growers needing to reduce soil erosion in the Palouse annual-cropped region of the Pacific Northwest, which is well suited for wheat production. A 6-yr field study was conducted to determine optimum levels of fertilizer and herbicide inputs in a no-till continuous wheat crop production system. Three levels of nitrogen (N) and two weed management levels (WML) were compared in a spring wheat (SW)–winter wheat (WW)–WW rotation through two rotation cycles. The high WML reduced weed densities about 50% compared with the low WML. In general, herbicide treatments were more effective on broadleaf weeds and may have facilitated a shift toward grass weeds. The high WML reduced grass weed biomass only at the reduced N levels, whereas the high WML reduced broadleaf weed density at all N levels. Variable environmental conditions affected wheat yield; however, yield tended to be highest where winter wheat immediately followed spring wheat. Nitrogen had little effect on weed density but increased crop yield about 13% with each increased N level. Crop yield was greater at the high versus low WML at each N level, even though weed density and biomass were reduced least between WMLs at the highest N level. The highest crop yield and net returns were obtained with the highest N and WML; however, none of the N and WML combinations were profitable.

scholarly journals Influence of Semiarid Cropping Systems on Root Diseases and Inoculum Density of Soilborne Pathogens

Plant Disease ◽  
2013 ◽  
Vol 97 (4) ◽  
pp. 547-555 ◽  
Author(s):  
Richard W. Smiley ◽  
Stephen Machado ◽  
Jennifer A. Gourlie ◽  
Larry C. Pritchett ◽  
Guiping Yan ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Cropping Systems ◽  
Spring Barley ◽  
The United States ◽  
Inoculum Density ◽  
Crown Rot ◽  
Gaeumannomyces Graminis ◽  
Fusarium Crown Rot ◽  
No Till ◽  
Chemical Fallow

There is interest in converting the 2-year rotation of rainfed winter wheat with cultivated fallow in the Pacific Northwest of the United States into direct-seed (no-till) systems that include chemical fallow, spring cereals, and food-legume and brassica crops. Eight cropping systems in a low-precipitation region (<330 mm) were compared over 9 years to determine effects of changes on diseases. Fusarium crown rot was more prevalent in wheat following cultivated than chemical fallow, and Rhizoctonia root rot was more severe when winter wheat was rotated with chemical fallow than with no-till winter pea. Take-all occurred even during the driest years and was more severe on annual spring wheat than on annual spring barley. Inoculum density (picograms of DNA per gram of soil) differed (α < 0.05) among cropping systems for Fusarium culmorum, F. pseudograminearum, Gaeumannomyces graminis var. tritici, and Pythium spp. but not for Rhizoctonia solani AG-8. Phoma medicaginis var. pinodella was detected only where winter pea was planted frequently. This is the first report of P. medicaginis as a component of the dryland stem rot complex of pea in north-central Oregon. Results of this investigation will provide guidance for developing crop species with resistance to Fusarium crown rot and black stem of pea.

Rattail Fescue (Vulpia Myuros) Control in Chemical-Fallow Cropping Systems

2008 ◽  
Vol 22 (3) ◽  
pp. 435-441 ◽  
Author(s):  
Eric D. Jemmett ◽  
Donald C. Thill ◽  
Traci A. Rauch ◽  
Daniel A. Ball ◽  
Sandra M. Frost ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Pacific Northwest ◽  
Conservation Tillage ◽  
Cropping Systems ◽  
Farming Systems ◽  
Conventional Tillage ◽  
Soil Disturbance ◽  
Effective Control ◽  
Panicle Number ◽  
Chemical Fallow

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.

Scouringrush (Equisetum spp.) control in dryland winter wheat

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.

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

Weed Science ◽  
1996 ◽  
Vol 44 (2) ◽  
pp. 429-436 ◽  
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.

Trends in Occurrence, Distribution, and Population Densities of Plant-Parasitic Nematodes in the Pacific Northwest of the United States from 2012 to 2016

2019 ◽  
Vol 20 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Inga A. Zasada ◽  
Megan Kitner ◽  
Catherine Wram ◽  
Nadine Wade ◽  
Russell E. Ingham ◽  
...  
Keyword(s):  
United States ◽  
Pacific Northwest ◽  
Parasitic Nematode ◽  
The United States ◽  
Plant Parasitic Nematode ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Population Densities ◽  
The Pacific ◽  
Plant Parasitic

The Pacific Northwest (PNW) of the United States (Idaho, Oregon, and Washington) is a diverse agricultural production area with over 400 different commodities grown in the region. Plant-parasitic nematodes are a constraint to the production of many of these commodities. Soil sample data from 2012 to 2016 were obtained from nematode diagnostic laboratories in the region to assess trends in occurrence, population densities, and distribution of plant-parasitic nematodes in the PNW. A total of 38,022 unique data points were analyzed. The number of plant-parasitic nematode samples processed in the PNW by diagnostic laboratories has significantly increased from 2012 to 2016. Fifteen genera of plant-parasitic nematodes were identified by diagnostic laboratories, with 86% of the samples in the PNW containing at least one plant-parasitic nematode genus. These laboratories provide a valuable service to agriculture in the PNW. Additionally, they serve as a rich source of information on plant-parasitic nematode distribution, occurrence, and abundance that, when analyzed, provides an empirical basis upon which to interpret individual grower reports and make management recommendations.

scholarly journals Geocenamus brevidens Associated with Reduced Yield of No-Till Annual Spring Wheat in Oregon

Plant Disease ◽  
2006 ◽  
Vol 90 (7) ◽  
pp. 885-890 ◽  
Author(s):  
Richard W. Smiley ◽  
Ruth G. Whittaker ◽  
Jennifer A. Gourlie ◽  
Sandra A. Easley
Keyword(s):  
Triticum Aestivum ◽  
Pacific Northwest ◽  
Spring Wheat ◽  
Cropping Systems ◽  
Wheat Yield ◽  
Economic Damage ◽  
Nematode Density ◽  
No Till ◽  
Single Location ◽  
The Pacific

Associations between stunt nematodes and yield of no-till annual spring wheat (Triticum aestivum) were examined at two eastern Oregon locations. Geocenamus brevidens was the only species detected at one location and was mixed with Tylenchorhynchus clarus at another location. Six cultivars were planted with or without application of aldicarb during 2001. Inverse correlations between yield and stunt nematode density were significant at the G. brevidens-only site (P = 0.04) but not the G. brevidens + T. clarus site (P = 0.44). Yields were inversely correlated (P < 0.01) with stunt nematode populations at both sites during 2002. Aldicarb improved grain yields at both locations during 2001 (17 and 24%, P < 0.01) but not at the single location treated with aldicarb during 2002 (10%, P = 0.06). A lack of association between yield and T. clarus in 19 previously unreported experiments is discussed. Reduced wheat yield in response to stunt nematodes in Oregon is likely due to parasitism by G. brevidens and not T. clarus. This is the first report associating G. brevidens with suppression of wheat yield in the Pacific Northwest. Further studies are needed to define cropping systems and locations where G. brevidens may cause economic damage.

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