MON 37500 rate and timing affects downy brome (Bromus tectorum) control in winter wheat (Triticum aestivum)

Weed Science ◽  
1998 ◽  
Vol 46 (3) ◽  
pp. 366-373 ◽  
Author(s):  
Patrick W. Geier ◽  
Phillip W. Stahlman ◽  
Francis E. Northam ◽  
Stephen D. Miller ◽  
Neal R. Hageman
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Field Experiments ◽  
Bromus Tectorum ◽  
Plant Density ◽  
Downy Brome ◽  
Herbicide Treatment

Field experiments were conducted at five locations in Colorado, Kansas, and Wyoming in 1994–1995 and 1995–1996 to compare the effects of MON 37500 rate and application timings on downy brome control and winter wheat tolerance. MON 37500 at 18 to 35 g ha−1applied preemergence or fall postemergence reduced downy brome density 71 to 92% in 1995. Spring-applied MON 37500 suppressed downy brome growth but did not reduce plant density. No application reduced downy brome density in 1996. At each location, downy brome was controlled best by MON 37500 applied preemergence or fall postemergence at 35 g ha−1. MON 37500 did not affect wheat height at Archer or Torrington, WY, and Burlington or Stratton, CO, but wheat treated preemergence or fall postemergence was taller than untreated wheat at Hays, KS, in 1995. Spring-postemergence-treated wheat at Hays in 1995 was shorter than untreated, preemergence-, or fall-postemergence-treated wheat. Wheat head density did not differ among treated and untreated plots at Torrington, but herbicide treatment increased wheat yields. Wheat head density increased with all MON 37500 treatments at Hays in 1995, as did yield. However, preemergence and fall-postemergence applications resulted in the highest wheat yields. No herbicide treatment affected head density or yield at Hays in 1996.

BromusControl in Winter Wheat (Triticum aestivum) with the Ethylthio Analog of Metribuzin

1987 ◽  
Vol 1 (3) ◽  
pp. 235-241 ◽  
Author(s):  
Randall L. Ratliff ◽  
Thomas F. Peeper
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Field Experiments ◽  
Bromus Tectorum ◽  
Downy Brome ◽  
Selective Control ◽  
Bromus Secalinus ◽  
Wide Range

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.

Control of Downy Brome (Bromus tectorum) in Winter Wheat (Triticum aestivum) with MON 37500

1998 ◽  
Vol 12 (3) ◽  
pp. 421-425 ◽  
Author(s):  
Robert E. Blackshaw ◽  
William M. Hamman
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Field Experiments ◽  
Bromus Tectorum ◽  
Production Systems ◽  
Wheat Yield ◽  
Downy Brome ◽  
Wheat Production ◽  
Winter Wheat Yield

Field experiments were conducted to determine suitable application timings and rates of MON 37500 for downy brome control in winter wheat. MON 37500 applied preemergence (PRE) or in fall postemergence (POST) provided better control of downy brome than when applied spring POST. MON 37500 at rates ranging from 19 to 33 g ai/ha applied PRE or fall POST controlled downy brome >85%. MON 37500 applied spring POST at 60 g/ha only suppressed growth of downy brome. Winter wheat was not visibly injured and maturity was not delayed by MON 37500 applied up to 60 g/ha at any of the application timings. Winter wheat yield responded positively to all MON 37500 treatments but PRE or fall POST applications usually resulted in greater yields than spring POST applications. Wheat yields progressively increased with increasing rates of MON 37500 up to 30–40 g/ha, above which yields tended to plateau or, in two instances, decline slightly. MON 37500 is an important new herbicide that should enable growers to better manage downy brome in winter wheat production systems.

Competition Between Winter Wheat (Triticum aestivum) Cultivars and Downy Brome (Bromus tectorum)

Weed Science ◽  
1986 ◽  
Vol 34 (5) ◽  
pp. 689-693 ◽  
Author(s):  
Challaiah ◽  
Orvin C. Burnside ◽  
Gail A. Wicks ◽  
Virgil A. Johnson
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Grain Yield ◽  
Stepwise Regression ◽  
Field Experiments ◽  
Bromus Tectorum ◽  
Growth Parameters ◽  
Yield Reduction ◽  
Downy Brome ◽  
Wheat Grain

Field experiments were conducted to select winter wheat (Triticum aestivumL.) cultivar(s) that were competitive to downy brome (Bromus tectorumL. # BROTE). Downy brome significantly reduced winter wheat grain yields of all cultivars by 9 to 21% at Lincoln, while at North Platte yield reduction ranged from 20 to 41% depending upon cultivar. ‘Turkey’ was the most competitive cultivar to downy brome but it had the lowest grain yield. Compared to ‘Centurk 78’, ‘Centura’ at Lincoln and ‘SD 75284’ at North Platte proved to be significantly higher yielding and more competitive to downy brome. Winter wheat tiller number, canopy diameter, and plant height were negatively correlated with downy brome yield, but changes in these growth parameters did not always translate into grain yield advantage in downy brome-infested plots. Based on stepwise regression analysis, wheat height was better correlated with reduction in downy brome yield than were canopy diameter or number of tillers.

Downy Brome (Bromus tectorum) Density and Relative Time of Emergence Affects Interference in Winter Wheat (Triticum aestivum)

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 551-556 ◽  
Author(s):  
Robert E. Blackshaw
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Seed Yield ◽  
Field Experiments ◽  
Bromus Tectorum ◽  
Wheat Yield ◽  
Growing Season ◽  
Early Spring ◽  
Downy Brome ◽  
Relative Time

Field experiments over 3 yr at Lethbridge, Alberta, determined the effect of various downy brome densities and times of its emergence on winter wheat biomass and seed yield. Downy brome reduced wheat biomass up to 59% and seed yield up to 68%. Time of downy brome emergence relative to wheat affected the magnitude of these yield reductions more than the density of downy brome. At comparable densities, downy brome caused 2- to 5-fold greater reductions in yield when it emerged within 3 wk after winter wheat than when it emerged 6 wk after wheat or in early spring. Late-emerging downy brome caused significant wheat yield or biomass losses only at densities of 200 to 400 plants m-2. Late-emerging downy brome plants were strongly shaded (70 to 90%) by winter wheat throughout much of the growing season.

Influence of Soil Type and Depth of Planting on Downy Brome Seed

Weed Science ◽  
1971 ◽  
Vol 19 (1) ◽  
pp. 82-86 ◽  
Author(s):  
G. A. Wicks ◽  
O. C. Burnside ◽  
C. R. Fenster
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Soil Type ◽  
Bromus Tectorum ◽  
Seedling Emergence ◽  
Cropping System ◽  
Soil Surface ◽  
Downy Brome ◽  
Moldboard Plow

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.

Inactivation of Metribuzin in Winter Wheat by Activated Carbon

Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 229-232 ◽  
Author(s):  
D. J. Rydrych
Keyword(s):  
Triticum Aestivum ◽  
Activated Carbon ◽  
Winter Wheat ◽  
Bromus Tectorum ◽  
Sandy Loam ◽  
Sandy Loam Soil ◽  
Silt Loam ◽  
Downy Brome ◽  
Chemical Injury ◽  
Loam Soil

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.

Differential Absorption and Translocation of Metribuzin by Downy Brome (Bromus tectorum) and Winter Wheat (Triticum aestivum)

Weed Science ◽  
1987 ◽  
Vol 35 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Daniel L. Devlin ◽  
David R. Gealy ◽  
Larry A. Morrow
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Bromus Tectorum ◽  
Wheat Root ◽  
Downy Brome ◽  
Fresh Weight Basis ◽  
Plant Parts ◽  
Root Absorption ◽  
Treated Leaf ◽  
Total Plant

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.

Differential Metabolism of Metribuzin by Downy Brome (Bromus tectorum) and Winter Wheat (Triticum aestivum)

Weed Science ◽  
1987 ◽  
Vol 35 (6) ◽  
pp. 741-745 ◽  
Author(s):  
Daniel L. Devlin ◽  
David R. Gealy ◽  
Larry A. Morrow
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Bromus Tectorum ◽  
Water Soluble ◽  
Chloroform Fraction ◽  
Downy Brome ◽  
Fresh Weight ◽  
Aqueous Fraction ◽  
Root Absorption

At both 15 and 25 C, following a 24-h root absorption period, absorbed14C-metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] was metabolized approximately 30% more rapidly to water-soluble and terminal fiber metabolites by winter wheat (Triticum aestivumL.) than by downy brome (Bromus tectorumL. # BROTE). Both species metabolized a greater proportion of metribuzin in leaf sheaths and roots than in the leaf blades. This was attributed to the increased incorporation of metribuzin into fiber. After an initial leaf extraction, metribuzin and the metabolites deaminated metribuzin (DA), deaminated diketo metribuzin (DADK), and diketo metribuzin (DK) partitioned into a chloroform fraction and five unidentified water-soluble metabolites into an aqueous fraction. At both 15 and 25 C, downy brome absorbed approximately three times more metribuzin per fresh weight than did winter wheat. The mechanism of differential tolerance of downy brome and winter wheat to metribuzin was attributed to the ability of winter wheat to metabolize metribuzin more rapidly and absorb less metribuzin than downy brome.

Retention, Absorption, and Loss of Foliage-Applied Metribuzin

Weed Science ◽  
1987 ◽  
Vol 35 (6) ◽  
pp. 775-779 ◽  
Author(s):  
Daniel L. Devlin ◽  
David R. Gealy ◽  
Larry A. Morrow
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Bromus Tectorum ◽  
Petri Dish ◽  
Downy Brome ◽  
Leaf Surfaces

Immediately following postemergence application, similar quantities of metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] were retained on the foliage of downy brome (Bromus tectorumL. # BROTE) and winter wheat (Triticum aestivumL.). Three days following treatment, more metribuzin was present on the surface of the foliage of downy brome than of winter wheat and similar quantities of metribuzin had been absorbed into the interior of the foliage of both species. Fourteen days after treatment, metribuzin had disappeared from the surfaces of the foliage of both species but more metribuzin was present in the interior of the foliage of downy brome than of winter wheat. Results from petri dish studies in the field suggested that the amount of unaltered metribuzin available for absorption by leaves was influenced primarily by volatilization and secondarily by photodecomposition. In addition, small quantities of rainfall may have washed metribuzin from leaf surfaces. In 1984, yield of winter wheat was greater in metribuzin-treated plots than in nontreated check plots.

Fertilizer and Downy Brome (Bromus tectorum) Effect on Russian Wheat Aphid (Diuraphis noxis) in Winter Wheat (Triticum aestivum)

1993 ◽  
Vol 7 (3) ◽  
pp. 670-673
Author(s):  
James M. Krall ◽  
Stephen D. Miller ◽  
Larry E. Bennett ◽  
David E. Legg
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Bromus Tectorum ◽  
Field Studies ◽  
Russian Wheat Aphid ◽  
Alternative Host ◽  
Downy Brome ◽  
Insecticide Efficacy

Downy brome serves as an alternative host for Russian wheat aphid (RWA) in winter wheat. In field studies, downy brome infestations of 5 and 39 plants per m2increased RWA-infested winter wheat tillers 1.4 to 2.8 times that seen in non-infested plots, respectively. RWA-infested winter wheat tillers were not reduced consistently by fertilization. Chlorpyrifos reduced the number of RWA-infested winter wheat tillers to 15 to 43% of untreated wheat. Insecticide efficacy was not influenced by downy brome infestation or by fertilizer either band- or broadcast-applied.

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