Split Applications of Herbicides at Reduced Rates Can Effectively Control Wild Oat (Avena fatua) in Wheat

2004 ◽  
Vol 18 (2) ◽  
pp. 369-374 ◽  
Author(s):  
Sam J. Lockhart ◽  
Kirk A. Howatt

Split application of herbicides for wild oat control may minimize wild oat competition with wheat while reducing the number of wild oat seeds returned to the soil. Field experiments were conducted in 2000 and 2001 to evaluate the effects of CGA-184927, fenoxaprop-P, flucarbazone, and ICIA 0604 at labeled and reduced rates on wild oat control, wild oat seed rain, and wheat yield. Each herbicide was applied once at 25, 33, and 100% of the labeled rate at the two-leaf stage of wild oat or split applied at 50 and 66% of the full rate as two equal applications. Excellent full-season wild oat control was obtained with CGA-184927, flucarbazone, and ICIA 0604 applied twice at reduced rates. ICIA 0604 or CGA-184927 split applied at 25 and 33% rates (totaled 50 and 66% of the full rate) provided wild oat control equal to one application of labeled rates. Wild oat seed rain was similar among all herbicide treatments, except plots treated with fenoxaprop-P once at 25 and 33% rates where seed rain was higher and equal to 47% of untreated plots. Wheat yields and net returns were highest and similar after treatment with CGA-184927 or ICIA 0604 applied either once at the labeled rate or split applied at 25 or 33% rates.

2003 ◽  
Vol 83 (4) ◽  
pp. 977-985 ◽  
Author(s):  
J. T. O’Donovan ◽  
K. Neil Harker ◽  
R. E. Blackshaw ◽  
R. N. Stougaard

Field experiments to investigate the effects of variable imazamethabenz rates on wild oat seed production and wheat yield and profitability were conducted at Lacombe, Lethbridge and Vegreville, Alberta, and Kalispell, Montana, over several years. Similar studies with difenzoquat were conducted at Lacombe and Lethbridge. In most cases, reducing the herbicide rates below those recommended resulted in increases in wild oat seed production, but the potential for returning relatively large amounts of wild oat seed to the soil seedbank depended on the extent of the rate reduction. For example, averaged over locations and years, reducing the rate of imazamethabenz to 75% of the recommended rate resulted in wild oat seed production increasing by 25% compared with an increase of over 100% when the rate was reduced to 50%. Wheat yields and economic returns as functions of rate also varied for both herbicides. It was more economical, in most cases, to apply imazamethabenz at 50 or 75% of the recommended rate compared with the full rate. However, an economic loss occurred in four and three of the 11 location-years when the imazamethabenz rate was reduced to 50 and 75%, respectively, and losses were more severe at the 50% rate. Compared with imazamethabenz, reducing the rate of difenzoquat tended to be more risky in terms of increased wild oat seed production and reduced net economic return. Key words: Reduced herbicide rates


Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Harry L. Carlson ◽  
James E. Hill

Field experiments were conducted to determine the effect of nitrogen fertilization on competition between wild oat (Avena fatuaL. # AVEFA) and spring wheat (Triticum aestivum‘Anza’). Nitrogen fertilizer treatments were applied over several wild oat-wheat density combinations. Wheat grain yield in wild oat-infested plots generally declined with fertilization while the density of wild oat panicles increased. Apparently, in competition with wheat, wild oat was better able to utilize the added nitrogen and thus gained a competitive advantage over the wheat. The increased competitiveness of wild oat resulted in reduced crop yields. Under the conditions of these experiments, nitrogen fertilization resulted in positive wheat yield response only when the wild oat plant density was below 1.6 percent of the total plant density.


1983 ◽  
Vol 63 (2) ◽  
pp. 503-507 ◽  
Author(s):  
M. P. SHARMA ◽  
W. H. VANDEN BORN

Field experiments were conducted over a 2-yr period to evaluate the need for competition by crop plants along with the application of postemergence herbicides for wild oat (Avena fatua L.) control in barley and wheat. Barban, difenzoquat, and barban plus difenzoquat were used in barley and barban, benzoylprop ethyl, diclofop methyl, flamprop methyl, and barban plus benzoylprop ethyl were used in wheat, at the two-leaf stage and the four-leaf stage of wild oats seeded alone or in a crop. Barban and diclofop methyl were effective for wild oat control at both the two-leaf and four-leaf stage of wild oats. Benzoylprop ethyl, difenzoquat and flamprop methyl alone or in combination with barban were more effective at the four-leaf than at the two-leaf stage of wild oats. Herbicide treatments increased barley yield up to 84% and wheat yield up to 177%. In the absence of herbicide treatments, crop competition from barley or wheat reduced the wild oat dry weight by about 50%. Competition by crop plants was essential for effective wild oat control with all foliage-applied wild oat herbicides included in this study.Key words: Competition, crop, wild oat, herbicides, wheat, barley


Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 176-181 ◽  
Author(s):  
Harry L. Carlson ◽  
James E. Hill

Field experiments were conducted to measure the grain yield of wheat (Triticum aestivumL. ‘ANZA’) at various wild oat (Avena fatuaL. ♯ AVEFA) and wheat plant densities. Wheat yield declined as wild oat plant density increased. Wheat yield increased in wild oat-infested plots as wheat plant density increased. Regression models were developed to describe the combined effect of wheat and wild oat plant densities on wheat grain yield. Wheat yields were best described by a nonlinear regression model using the relative density of wild oat in the weed-crop stand as the dependent variable. Inclusion of crop stand as a competitive factor significantly improved the fit of all regression models tested. Wild oat were more competitive against wheat in these experiments than in experiments reported by others. Possible reasons for differences in observed competitiveness are discussed.


1997 ◽  
Vol 11 (1) ◽  
pp. 30-34
Author(s):  
Jeffrey A. Koscelny ◽  
Thomas F. Peeper

Seven field experiments were conducted in Oklahoma to compare efficacy and wheat response to currently registered cheat suppression or control herbicide treatments. Chlorsulfuron + metsulfuron premix (5:1 w/w) at 26 g ai/ha applied PRE controlled cheat 20 to 61%, increased wheat grain yields at two of seven locations, and decreased dockage due to cheat at five of seven locations. Chlorsulfuron + metsulfuron at 21 g/ha tank-mixed with metribuzin at 210 g/ha, applied early fall POST, controlled cheat 36 to 98% and increased wheat yield at four of seven locations. Metribuzin applied POST in the fall at 420 g/ha controlled cheat 56 to 98% and increased wheat yields at five of seven locations. Both POST treatments decreased dockage at all locations.


Weed Science ◽  
1980 ◽  
Vol 28 (2) ◽  
pp. 152-158 ◽  
Author(s):  
E. E. Schweizer

Twelve sequential herbicide treatments were compared to cycloate (S-ethylN-ethylthiocyclohexanecarbamate), a standard treatment, for control of annual weeds in sugarbeets (Beta vulgarisL.) in three field experiments conducted from 1971 through 1977. At harvest, seven sequential treatments had less than 10 annual broadleaf weeds per 30 m of row, whereas there were 40 broadleaf weeds per 30 m of row for the cycloate treatment. Four of these sequential treatments had significantly higher root yields and net returns than the cycloate treatment. Dependent on the sequential treatment and year, tonnage was increased 7.3 to 20.3 t/ha, and net returns $150 to $515/ha above those with cycloate. The most effective sequential treatment for control of weeds was a preplanting mixture of 2.2 kg/ha of ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate] plus 1.7 kg/ha of diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid} followed by a postemergence mixture of 0,6 kg/ha each of desmedipham [ethylm-hydroxycarbanilate carbanilate (ester)] plus phenmedipham (methylm-hydroxycarbanilatem-methylcarbanilate). This sequential herbicide treatment increased root yields by an average of 20.3 t/ha and net returns by $515/ha above those with cycloate.


1994 ◽  
Vol 8 (3) ◽  
pp. 607-611 ◽  
Author(s):  
Kenneth J. Kirkland

The influence of incorporation vs no incorporation on the efficacy of granular triallate applied in mid-October at 1400 and 1700 g ai/ha to control wild oat was evaluated in spring wheat in west central Saskatchewan over a 7-yr period. All fall-applied triallate reduced wild oat panicles and fresh weight, and increased yield compared to untreated checks. With applications in standing wheat stubble there was no difference in wild oat control from incorporation versus no incorporation. All triallate treatments reduced wild oat panicles and fresh weight by over 95%, and resulted in wheat yield increases ranging from 29 to 67%. In tilled fallow, incorporated granules provided better wild oat control than when there was no incorporation. Wheat yield increases ranged from 50 to 85% for triallate treatments with yield for incorporated triallate approximately 15% greater than non-incorporated. The rate of triallate did not affect the level of wild oat control achieved with either incorporation method. In separate tolerance studies triallate incorporation method did not affect spring wheat emergence or subsequent development.


1999 ◽  
Vol 79 (3) ◽  
pp. 447-453 ◽  
Author(s):  
A. L. Darwent ◽  
J. R. Moyer

Wild oat (Avena fatua L.) control from three graminicides, clodinafop-propargyl, fenoxaprop-p-ethyl and tralkoxydim, in seedling stands of smooth bromegrass (Bromus inermis L.) seeded alone or with spring wheat (Triticum aestivum L.) was studied in 1991, 1992 and 1993 at Beaverlodge, Alberta. Seed yield and quality were measured for 2 yr after each year of establishment. In the year of establishment, clodinafop-propargyl at 60 g ha–1 consistently provided ≥80% visual control of wild oat growing in smooth bromegrass seeded with wheat, while the mean probability of similar applications of fenoxaprop-p-ethyl at 92 g ha−1 and tralkoxydim at 250 g ha−1 to provide ≥80% visual control of wild oat, averaged over the years of establishment, was 0.91 and 0.92, respectively. Without the wheat companion crop, the mean probability of clodinafop-propargyl to provide ≥80% visual control of wild oat, averaged over establishment years, remained above 0.90, but that for fenoxaprop-p-ethyl and tralkoxydim was reduced to 0.36 and 0.50, respectively. The efficacy of the three graminicides to control wild oat was reduced by tank mixing with bromoxynil plus MCPA, thifensulfuron methyl plus MCPA, or MCPA alone. Establishment with wheat had a major detrimental impact on smooth bromegrass seed yields harvested 1 and 2 yr after each establishment year. Smooth bromegrass seed yields harvested 1 yr following the year of establishment were three times greater where smooth bromegrass was seeded alone as compared with being seeded with wheat. Seed yields harvested 2 yr after the year of establishment followed a similar trend, but the differences were smaller. Herbicide treatments had no effect on either first or second smooth bromegrass seed yields. Wild oat dockage was present only in the first smooth bromegrass seed crop and was approximately three times greater following establishment with wheat than following establishment alone. Percent wild oat dockage was less from plots where herbicides had been applied than from weedy check plots. Differences in percent dockage occurred among herbicide treatments but were small. Key words: Smooth bromegrass, Bromus inermis, wild oat, Avena fatua, graminicides, tank mixtures


2018 ◽  
Vol 98 (3) ◽  
pp. 601-608 ◽  
Author(s):  
Amy R. Mangin ◽  
Linda M. Hall ◽  
Jeff J. Schoenau ◽  
Hugh J. Beckie

Tillage and new herbicide options may be necessary for the control of herbicide-resistant wild oat. The efficacy of soil-applied herbicides such as pyroxasulfone can be influenced by edaphic factors and weed seed recruitment depth, which varies with tillage system. We investigated the effect of tillage and pyroxasulfone rate when applied in the fall and spring on wild oat biomass at three locations in Alberta in 2014–2015. The vertical position of wild oat seeds, with and without tillage, was examined at each site. Wild oat biomass was greater in untilled plots compared with plots with fall tillage at all locations. In two out of three locations, pyroxasulfone efficacy was superior when applied in the fall compared with spring, possibly influenced by low spring rainfall. A single tillage pass at the Edmonton and Kinsella locations did not affect wild oat seed distribution, but there was an increase in seeds present in the surface layer in the untilled treatment at Lacombe. Tillage, used in combination with soil-applied herbicides, may be an option to achieve acceptable control of herbicide-resistant wild oat.


1993 ◽  
Vol 7 (4) ◽  
pp. 890-893 ◽  
Author(s):  
Kenneth J. Kirkland

The effect of duration of wild oat competition on spring wheat yield and growth was determined in time-of-removal experiments conducted over a three year study period in Saskatchewan, Canada. Failure to remove wild oat reduced wheat yield 28 and 39% at wild oat populations of 64 and 188 plants per m2, respectively. Wheat yield was not reduced by wild oat densities of 64 or 118 plants per m2until the six- and seven-leaf stage of wild oat, respectively. Removing wild oat at 64 plants per m2before the seven-leaf stage and 118 plants per m2before the five-leaf stage did not increase wheat culm or fresh weight production.


Sign in / Sign up

Export Citation Format

Share Document