Chemical and Biological Control of Downy Brome (Bromus tectorum) in Wheat and Alfalfa in North America

Weed Science ◽  
1984 ◽  
Vol 32 (S1) ◽  
pp. 18-25 ◽  
Author(s):  
Thomas F. Peeper

As an agrestal weed, downy brome (Bromus tectorumL. # BROTE) is most troublesome in winter wheat (Triticum aestivumL. # TRIAE) and alfalfa (Medicago sativaL. # MEDSA) because of the ability of downy brome to reproduce prior to crop harvesting (70, 76). Geographically, downy brome is most common in the western half of the United States where annual rainfall totals 15 to 55 cm and autumn rainfall ranges from 5 to 12 cm (10, 11, 86, 98). In contrast, cheat (Bromus secalinusL. # BROSE) is more common in the eastern portion of the hard red winter wheat producing regions and in the more humid soft red winter wheat region. Behrendt and Hanf (12) state that cheat has been more common on acid sandy or loamy soils while downy brome commonly occurs on dry, mostly alkaline, sandy to loamy soils. Since soils are frequently alkaline in the relatively dry climate of the western regions (61), it is not clear exactly what role pH plays in affecting geographical distribution of the variousBromusspp. Recent serious problems with downy brome in the New England nursery industry (69) and orchards (57) indicate that downy brome could thrive under a relatively wide range of edaphic and climatic conditions. However, as a weed problem in wheat, the common prevalent conditions of low annual precipitation and alkaline soils should not go unnoticed in the development of chemical weed control practices.

1987 ◽  
Vol 1 (3) ◽  
pp. 235-241 ◽  
Author(s):  
Randall L. Ratliff ◽  
Thomas F. Peeper

Twenty field experiments were conducted in Oklahoma from 1983 through 1986 to evaluate the ethylthio analog of metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(ethylthio)-1,2,4-triazin-5(4H)-one] for selective control of cheat (Bromus secalinusL. #3BROSE), downy brome (Bromus tectorumL. # BROTE), and rescuegrass (Bromus catharticusVahl. # BROCA) in winter wheat (Triticum aestivumL.). The ethylthio analog of metribuzin applied postemergence at 1.1 kg ai/ha before the weeds tillered controlled 91 to 100% of theseBromusspp. in winter wheat. Control of tilleredBromusspp. was less consistent. AsBromusspp. control increased, wheat yields increased, and dockage decreased. The herbicide was selective on wheat over a wide range of soils, including sands. Adding surfactant to very early postemergence applications of 0.6 kg ai/ha increased cheat control but injured wheat slightly. Surfactant use had little or no effect on dockage reduction and yields.


Plant Disease ◽  
2015 ◽  
Vol 99 (9) ◽  
pp. 1261-1267 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Hughes

Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from wheat fields and breeding plots by USDA-ARS personnel and cooperators in the Great Plains, Ohio River Valley, and southeastern states in order to determine the virulence of the wheat leaf rust population in 2013. Single uredinial isolates (490 total) were derived from the collections and tested for virulence phenotype on 20 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes. In 2013, 79 virulence phenotypes were described in the United States. Virulence phenotypes MBTNB, TNBGJ, and MCTNB were the three most common phenotypes. Phenotypes MBTNB and MCTNB are both virulent to Lr11, and MCTNB is virulent to Lr26. MBTNB and MCTNB were most common in the soft red winter wheat region of the southeastern states and Ohio Valley. Phenotype TNBGJ is virulent to Lr39/41 and was widely distributed throughout the hard red winter wheat region of the Great Plains. Isolates with virulence to Lr11, Lr18, and Lr26 were common in the southeastern states and Ohio Valley region. Isolates with virulence to Lr21, Lr24, and Lr39/41 were frequent in the hard red wheat region of the southern and northern Great Plains.


Weed Science ◽  
1971 ◽  
Vol 19 (1) ◽  
pp. 82-86 ◽  
Author(s):  
G. A. Wicks ◽  
O. C. Burnside ◽  
C. R. Fenster

Downy brome (Bromus tectorumL.) seedling emergence was greatest from soil depths of 1 inch or less, but occasionally seedlings emerged from depths of 4 inches. Downy brome seed covered by soil germinated more rapidly than those seed on the soil surface. More downy brome seedlings emerged, and from greater depths, from coarse-textured soils than fine-textured soils when moisture was not limiting. Soil type did not influence longevity of downy brome seed buried in the soil. Most (98%) 8-month-old downy brome seed buried 8 inches in the soil germinated but did not emerge in 1 year; and none remained viable in the soil after 5 years. The moldboard plow was more effective in reducing downy brome populations than a sweep plow or one-way disk in a continuous winter wheat (Triticum aestivumL.) cropping system.


Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 229-232 ◽  
Author(s):  
D. J. Rydrych

Preemergence and postemergence application of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)-one] at 0.6 and 1.1 kg ai/ha controlled downy brome (Bromus tectorumL. ♯ BROTE) in winter wheat (Triticum aestivumL. ‘McDermid’) but caused considerable injury without the use of activated carbon over the seeded row. Activated carbon applied in 5-cm bands over the seeded row at 84, 167, and 336 kg/ha protected winter wheat at Pendleton on a silt loam soil. On a sandy loam soil, only a 336 kg/ha rate provided protection from metribuzin. Metribuzin toxicity to winter wheat was more difficult to neutralize when applied preemergence. Downy brome control was not reduced by carbon applied over the wheat row. The best treatment in this study was carbon at 336 kg/ha applied preemergence over the row followed by metribuzin at 0.6 or 1.1 kg/ha postemergence. A 10-week delay between preemergence carbon banding and postemergence metribuzin protected winter wheat from chemical injury.


Weed Science ◽  
1990 ◽  
Vol 38 (3) ◽  
pp. 224-228 ◽  
Author(s):  
Phillip W. Stahlman ◽  
Stephen D. Miller

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.


Weed Science ◽  
1984 ◽  
Vol 32 (S1) ◽  
pp. 7-12 ◽  
Author(s):  
Donald C. Thill ◽  
K. George Beck ◽  
Robert H. Callihan

Downy brome (Bromus tectorumL. # BROTE), also known as cheatgrass, downy chess, broncograss, Mormon oats, and junegrass, was introduced into the United States from Europe, apparently during the middle of the nineteenth century (11, 21). According to Mack (23), downy brome entered British Columbia, Washington, and Utah around 1890; and by 1928 it had reached its present range, occupying much of the perennial grassland in Washington, Idaho, Oregon, Nevada, Utah, and British Columbia. Today, downy brome is a widespread weed throughout most of Canada, Mexico, and the United States, except for the southeastern United States (5, 17). Some consider downy brome to be an important forage because it provides most of the early spring grazing for livestock in western United States rangeland (21). However, it is also considered a troublesome weed in rangeland (31), winter wheat (Triticum aestivumL.) (27), several other crops (29), and noncropland (32).


Weed Science ◽  
1987 ◽  
Vol 35 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Daniel L. Devlin ◽  
David R. Gealy ◽  
Larry A. Morrow

Foliar and root absorption and translocation of metribuzin (4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one) by downy brome (Bromus tectorumL. # BROTE) and winter wheat (Triticum aestivumL.) was determined. After a 48-h absorption period, roots of three-week-old downy brome plants had absorbed two times more metribuzin on a total plant fresh weight basis than had roots of winter wheat. Root-absorbed metribuzin was translocated similarly regardless of species with 80% of absorbed14C accumulating in leaf blades, 10% in the leaf sheaths, and 10% in the roots. After 24 h, leaves of downy brome and winter wheat had absorbed, respectively, 26 and 36% of foliar-applied metribuzin, and absorption increased threefold with the addition of a nonionic surfactant. Translocation of foliar-absorbed metribuzin was primarily towards the apex of the treated leaf. No translocation from the treated leaf to other plant parts occurred with either species. The greater tolerance of winter wheat to metribuzin is due in part to less root absorption of metribuzin by winter wheat than by downy brome.


1990 ◽  
Vol 70 (3) ◽  
pp. 629-637 ◽  
Author(s):  
CHARLES F. McGUIRE ◽  
LARRY G. BLACKWOOD

The United States Department of Agriculture (USDA) grading standards for wheat places hard red spring and hard red winter (Triticum aestivum L. em. Thell) wheat into separate classes. One important criterion for this designation is kernel type. Because of genotypes being released by plant breeders in recent years, distinction between these two classes is difficult for grain graders. As a consequence some people in the grain industry favor placing both of these wheat types into one class. One hazard of this action is that end use properties of these two wheats, according to some industrial firms, is class dependent. We studied quality characteristics of five hard red spring and seven hard red winter wheat cultivars grown at the same three Montana locations in 5 different years to evaluate this concept. Analysis of variance indicated quality differences between classes for all traits except flour yields, which were similar for the two classes. Flour ash content, farinograph absorption, peak time, stability time, valorimeter, grain protein content, bake absorption, mix time, and loaf volume were all significantly higher for spring than winter wheats. These values were still higher for spring than winter wheats except for test weight when wheat protein content was the co-variate. Both statistical treatments show that hard red spring wheat flour has higher water absorption percent, longer dough mixing requirements, longer dough stability times, and higher loaf volumes than hard red winter wheat flour.Key words: Bread wheat quality, loaf volume, grain protein content, protein quality


Weed Science ◽  
1984 ◽  
Vol 32 (S1) ◽  
pp. 2-6 ◽  
Author(s):  
Larry A. Morrow ◽  
Phillip W. Stahlman

Downy brome (Bromus tectorumL. # BROTE) has developed into a severe weed in several agricultural production systems throughout North America, particularly on rangeland and in winter wheat (Triticum aestivumL.). Several million hectares of winter wheat, pastureland, alfalfa (Medicago sativaL.), grass seed fields, and overgrazed rangeland, as well as other crops, have been invaded by this annual grass since its introduction into this hemisphere. Downy brome is most abundant in the Great Basin and Columbia Basin areas of the western United States, but is found throughout the continental United States and parts of Canada and Mexico. In some cases, the vegetation on overgrazed rangeland consists totally of downy brome, while winter wheat growers in the western United States proclaim it as their worst weed problem. Changes in tillage practices that are currently being implemented for the control of soil erosion coupled with the lack of selective herbicides for the control of downy brome have aided its increase and spread.


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