scholarly journals Models for Predicting Potential Yield Loss of Wheat Caused by Stripe Rust in the U.S. Pacific Northwest

2011 ◽  
Vol 101 (5) ◽  
pp. 544-554 ◽  
Author(s):  
D. Sharma-Poudyal ◽  
X. M. Chen
Keyword(s):  
Winter Wheat ◽  
Pacific Northwest ◽  
Stripe Rust ◽  
Spring Wheat ◽  
Yield Loss ◽  
Wheat Yield ◽  
The Other ◽  
Potential Yield ◽  
Highly Correlated ◽  
The U.S

Climatic variation in the U.S. Pacific Northwest (PNW) affects epidemics of wheat stripe rust caused by Puccinia striiformis f. sp. tritici. Previous models only estimated disease severity at the flowering stage, which may not predict the actual yield loss. To identify weather factors correlated to stripe rust epidemics and develop models for predicting potential yield loss, correlation and regression analyses were conducted using weather parameters and historical yield loss data from 1993 to 2007 for winter wheat and 1995 to 2007 for spring wheat. Among 1,376 weather variables, 54 were correlated to yield loss of winter wheat and 18 to yield loss of spring wheat. Among the seasons, winter temperature variables were more highly correlated to wheat yield loss than the other seasons. The sum of daily temperatures and accumulated negative degree days of February were more highly correlated to winter wheat yield loss than the other monthly winter variables. In addition, the number of winter rainfall days was found correlated with yield loss. Six yield loss models were selected for each of winter and spring wheats based on their better correlation coefficients, time of weather data availability during the crop season, and better performance in validation tests. Compared with previous models, the new system of using a series of the selected models has advantages that should make it more suitable for forecasting and managing stripe rust in the major wheat growing areas in the U.S. PNW, where the weather conditions have become more favorable to stripe rust.

Impact of Preceding Crop and Cultural Practices on Rye Growth in Winter Wheat

2009 ◽  
Vol 23 (4) ◽  
pp. 564-568 ◽  
Author(s):  
Randy L. Anderson
Keyword(s):  
Winter Wheat ◽  
Spring Wheat ◽  
Yield Loss ◽  
Cultural Practices ◽  
Wheat Yield ◽  
Seeding Rate ◽  
Starter Fertilizer ◽  
Preceding Crop ◽  
Winter Wheat Yield ◽  
The Impact

Improving crop vigor can suppress growth of weeds present in the crop. This study examined the impact of preceding crop and cultural practices on rye growth in winter wheat. Preceding crops were soybean, spring wheat, and an oat/dry pea mixture. Two cultural treatments in winter wheat were also compared, referred to as conventional and competitive canopies. The competitive canopy differed from the conventional in that the seeding rate was 67% higher and starter fertilizer was banded with the seed. The study was conducted at Brookings, SD. Rye seed and biomass production differed fourfold among treatments, with winter wheat following oat/pea being most suppressive of rye growth. Rye produced 63 seeds/plant in winter wheat with a competitive canopy that followed oat/pea, contrasting with 273 seeds/plant in conventional winter wheat following spring wheat. Yield loss in winter wheat due to rye interference increased with rye biomass, but winter wheat was more tolerant of rye interference following oat/pea compared with the other preceding crops. Regression analysis indicated that winter wheat yield loss at the same rye biomass was threefold higher following spring wheat or soybean compared with oat/pea as a preceding crop. Winter wheat competitiveness and tolerance to rye can be improved by increasing the seeding rate, using a starter fertilizer, and growing winter wheat after an oat/pea mixture.

Interference and Control of ALS-Resistant Mouse-Ear Cress (Arabidopsis thaliana) in Winter Wheat

2018 ◽  
Vol 32 (6) ◽  
pp. 671-677
Author(s):  
Ranjeet S. Randhawa ◽  
James H. Westwood ◽  
Charles W. Cahoon ◽  
Michael L. Flessner
Keyword(s):  
Winter Wheat ◽  
Control Mouse ◽  
Yield Loss ◽  
Wheat Yield ◽  
Acetolactate Synthase ◽  
Potential Yield ◽  
Resistant Mouse ◽  
Greenhouse Trial ◽  
Mouse Ear ◽  
And Control

AbstractIn 2015, winter wheat growers in Virginia reported commercial failures of thifensulfuron to control mouse-ear cress. This was the first reported case of field-evolved acetolactate synthase (ALS) resistance in mouse-ear cress, so research was conducted to evaluate alternative herbicide options as well as to document potential yield loss in winter wheat from mouse-ear cress. Efficacy studies were conducted at three site-years in 2015 to 2016 and 2016 to 2017 as well as a POST greenhouse trial. In the PRE study, flumioxazin, pyroxasulfone, saflufenacil, and metribuzin resulted in more than 80% mouse-ear cress control 15 wk after planting across all sites with no observable wheat injury. No differences were observed in wheat yield in two of three sites in the PRE herbicide study; yield differences were attributed to common chickweed and not to mouse-ear cress. In the POST herbicide study, 2,4-D, dicamba, and metribuzin resulted in greater than 75% control in the field and greenhouse. Metribuzin, dicamba, and pyroxsulam resulted in crop injury 3 wk after treatment at some sites, but injury was transient. Yield from all POST treatments was similar to the nontreated plots. No yield loss was observed by mouse-ear cress densities greater than 300 plants m–2, indicating that mouse-ear cress is not very competitive with winter wheat. Growers should make herbicide decisions based on other weeds in the field and can incorporate the aforementioned herbicides for mouse-ear cress control.

scholarly journals Potential wheat yield loss due to weeds in the United States and Canada

2021 ◽  
pp. 1-19
Author(s):  
Michael L. Flessner ◽  
Ian C. Burke ◽  
J. Anita Dille ◽  
Wesley J. Everman ◽  
Mark J. VanGessel ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Spring Wheat ◽  
Best Management Practices ◽  
Management Practices ◽  
Yield Loss ◽  
Wheat Yield ◽  
Weighted Average ◽  
The United States ◽  
Total Production ◽  
The Us

Abstract Yield losses due to weeds are a major threat to wheat production and economic well-being of farmers in the United States (US) and Canada. The objective of this Weed Science Society of America (WSSA) Weed Loss Committee report is to provide estimates of wheat yield and economic losses due to weeds. Weed scientists provided both weedy (best management practices but no weed control practices) and weed-free (best management practices providing >90% weed control) average yield from replicated research trials in both winter and spring wheat from 2007 to 2017. Winter wheat yield loss estimates ranged from 2.9 to 34.4%, with a weighted average (by production) of 25.6% for the US, 2.9% for Canada, and 23.4% combined. Based on these yield loss estimates and total production, the potential winter wheat loss due to weeds is 10.5, 0.09, and 10.5 billion kg with a potential loss in value of US$ 2.19, 0.19, and 2.19 billion for the US, Canada, and combined, respectively. Spring wheat yield loss estimates ranged from 7.9 to 47.0%, with a weighted average (by production) of 33.2% for the US, 8.0% for Canada, and 19.5% combined. Based on this yield loss estimate and total production, the potential spring wheat loss is 4.8, 1.6, and 6.6 billion kg with a potential loss in value of US$ 1.14, 0.37, and 1.39 billion for the US, Canada, and combined, respectively. Yield loss in this analysis is greater than some previous estimates, likely indicating an increasing threat from weeds. Climate impacts yield loss in winter wheat in the Pacific Northwest, with percent yield loss highest in wheat-fallow systems with less than 30 cm of annual precipitation. Continued investment in weed science research for wheat is critical for continued yield protection.

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.

scholarly journals Environmental Conditions Associated with Stripe Rust in Kansas Winter Wheat

Plant Disease ◽  
2016 ◽  
Vol 100 (11) ◽  
pp. 2306-2312 ◽  
Author(s):  
B. S. Grabow ◽  
D. A. Shah ◽  
E. D. DeWolf
Keyword(s):  
Soil Moisture ◽  
Winter Wheat ◽  
Stripe Rust ◽  
Yield Loss ◽  
Initial Step ◽  
Disease Forecasting ◽  
Estimation Equations ◽  
Forecasting System ◽  
Moisture Conditions ◽  
General Estimation

Stripe rust has reemerged as a problematic disease in Kansas wheat. However, there are no stripe rust forecasting models specific to Kansas wheat production. Our objective was to identify environmental variables associated with stripe rust epidemics in Kansas winter wheat as an initial step in the longer-term goal of developing predictive models for stripe rust to be used within the state. Mean yield loss due to stripe rust on susceptible varieties was estimated from 1999 to 2012 for each of the nine Kansas crop reporting districts (CRD). A CRD was classified as having experienced a stripe rust epidemic when yield loss due to the disease equaled or exceeded 1%, and a nonepidemic otherwise. Epidemics were further classified as having been moderate or severe if yield loss was 1 to 14% or greater than 14%, respectively. The binary epidemic categorizations were linked to a matrix of 847 variables representing monthly meteorological and soil moisture conditions. Classification trees were used to select variables associated with stripe rust epidemic occurrence and severity (conditional on an epidemic having occurred). Selected variables were evaluated as predictors of stripe rust epidemics within a general estimation equations framework. The occurrence of epidemics within CRD was linked to soil moisture during the fall and winter months. In the spring, severe epidemics were linked to optimal (7 to 12°C) temperatures. Simple environmentally based stripe rust models at the CRD level may be combined with field-level disease observations and an understanding of varietal reaction to stripe rust as part of an operational disease forecasting system in Kansas.

scholarly journals Impact of site-specific weed management on herbicide savings and winter wheat yield  

2013 ◽  
Vol 59 (No. 3) ◽  
pp. 101-107 ◽  
Author(s):  
P. Hamouz ◽  
K. Hamouzová ◽  
J. Holec ◽  
L. Tyšer
Keyword(s):  
Winter Wheat ◽  
Weed Management ◽  
Wheat Yield ◽  
The Other ◽  
Herbicide Application ◽  
Site Specific ◽  
Treatment Thresholds ◽  
Patch Spraying ◽  
Winter Wheat Yield ◽  
Weed Infestation

An aggregated distribution pattern of weed populations provides opportunity to reduce the herbicide application if site-specific weed management is adopted. This work is focused on the practical testing of site-specific weed management in a winter wheat and the optimisation of the control thresholds. Patch spraying was applied to an experimental field in Central Bohemia. Total numbers of 512 application cells were arranged into 16 blocks, which allowed the randomisation of four treatments in four replications. Treatment 1 represented blanket spraying and the other treatments differed by the herbicide application thresholds. The weed infestation was estimated immediately before the post-emergence herbicide application. Treatment maps for every weed group were created based on the weed abundance data and relevant treatment thresholds. The herbicides were applied using a sprayer equipped with boom section control. The herbicide savings were calculated for every treatment and the differences in the grain yield between the treatments were tested using the analysis of variance. The site-specific applications provided herbicide savings ranging from 15.6% to 100% according to the herbicide and application threshold used. The differences in yield between the treatments were not statistically significant (P = 0.81). Thus, the yield was not lowered by site-specific weed management.

Downy Brome (Bromus tectorum) Interference and Economic Thresholds in Winter Wheat (Triticum aestivum)

Weed Science ◽  
1990 ◽  
Vol 38 (3) ◽  
pp. 224-228 ◽  
Author(s):  
Phillip W. Stahlman ◽  
Stephen D. Miller
Keyword(s):  
Winter Wheat ◽  
Bromus Tectorum ◽  
Yield Loss ◽  
Wheat Yield ◽  
Dry Weight ◽  
Quadratic Equation ◽  
Downy Brome ◽  
Economic Threshold ◽  
Weed Density ◽  
Economic Thresholds

Densities up to 100 downy brome m2were established in winter wheat in southeastern Wyoming and west-central Kansas to quantify wheat yield loss from downy brome interference and to approximate economic threshold levels. A quadratic equation best described wheat yield loss as a function of weed density when downy brome emerged within 14 days after wheat emergence. Densities of 24, 40, and 65 downy brome m2reduced wheat yield by 10, 15, and 20%, respectively. Wheat yield was not reduced when downy brome emerged 21 or more days later than wheat. Economic thresholds varied with changes in downy brome density, cost of control, wheat price, and potential wheat yield. In a greenhouse experiment, dry weight of 72-day-old wheat plants grown in association with downy brome was not affected by the distance between the weeds and wheat, whereas downy brome plant dry weight increased with increasing distance between the weeds and wheat.

Effects of summer and winter annual scentless chamomile (Matricaria perforata Mérat) interference on spring wheat yield

1991 ◽  
Vol 71 (3) ◽  
pp. 841-850 ◽  
Author(s):  
D. W. Douglas ◽  
A. G. Thomas ◽  
D. P. Peschken ◽  
G. G. Bowes ◽  
D. A. Derksen
Keyword(s):  
Spring Wheat ◽  
Yield Loss ◽  
Wheat Yield ◽  
Weather Conditions ◽  
Yield Reduction ◽  
Hyperbolic Model ◽  
Loss Parameter ◽  
Winter Annuals ◽  
Winter Annual ◽  
Experimental Plots

The influence of summer and winter annual scentless chamomile (Matricaria perforata Mérat) on the yield of spring wheat in Saskatchewan was determined. In experimental plots, spring wheat was seeded into barley stubble where summer and winter annual scentless chamomile had been established. A rectangular hyperbolic model was used to describe the relationship between wheat yield and the density of flowering scentless chamomile plants. Winter annuals caused more yield reduction than did summer annuals. Weather conditions appeared to have an influence on the effect of scentless chamomile on spring wheat yield. The same model was fitted to sample data from farmers' fields and showed yield losses similar to those on the experimental plots. The rectangular hyperbolic model fitted the data best when high weed densities occurred. At densities more typical of those found in farm fields, the asymptotic yield loss parameter of the model was poorly estimated. Key words: Scentless chamomile, Matricaria perforata, yield loss, weed competition, rectangular hyperbola, spring wheat

Diagnostic Guide: Wheat Soil-Borne Mosaic

2018 ◽  
Vol 19 (2) ◽  
pp. 163-167 ◽  
Author(s):  
Duncan R. Kroese ◽  
Sudeep Bag ◽  
Ken E. Frost ◽  
Tim D. Murray ◽  
Christina H. Hagerty
Keyword(s):  
Winter Wheat ◽  
Mosaic Virus ◽  
Virus Replication ◽  
Spring Wheat ◽  
Yield Loss ◽  
Geographic Location ◽  
Polymyxa Graminis ◽  
Soil Temperatures ◽  
Important Host

Wheat soil-borne mosaic is caused by the rod-shaped Soil-borne wheat mosaic virus (SBWMV), which is in the genus Furovirus. SBWMV is vectored by Polymyxa graminis. Economic hosts of SBWMV include wheat, barley, and rye. Winter wheat is the most economically important host; spring wheat infections are possible but rare owing to unfavorable soil temperatures slowing virus replication. Yield loss owing to SBWMV infection is variable among season and geographic location.

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