Halauxifen-methyl controls glyphosate-resistant horseweed (Conyza canadensis) but not giant ragweed (Ambrosia trifida) in winter wheat

AbstractHorseweed is a competitive summer or winter annual weed that produces up to 230,000 small seeds per plant that are capable of traveling more than 500 km via wind. Giant ragweed is a tall, highly competitive summer annual weed. Glyphosate-resistant (GR) horseweed and GR giant ragweed pose significant challenges for producers in the United States and Ontario, Canada. It is thought that an integrated weed management (IWM) system involving herbicide rotation is required to control GR biotypes. Halauxifen-methyl is a new selective broadleaf POST herbicide registered for use in cereal crops; there is limited information on its efficacy on horseweed and giant ragweed. The purpose of this research was to determine the efficacy of halauxifen-methyl applied POST, alone and in a tank mix, for the control of GR horseweed and GR giant ragweed in wheat across southwestern Ontario. For each weed species, an efficacy study consisting of six field experiments was conducted over a 2-yr period (2018, 2019). At 8 wk after application (WAA), halauxifen-methyl, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, 2,4-D ester, clopyralid, and pyrasulfotole/bromoxynil + ammonium sulfate controlled GR horseweed >95%. Fluroxypyr and MCPA provided only 86% and 37% control of GR horseweed, respectively. At 8 WAA, fluroxypyr, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, fluroxypyr/halauxifen-methyl + MCPA EHE + pyroxsulam, 2,4-D ester, clopyralid, and thifensulfuron/tribenuron + fluroxypyr + MCPA ester controlled GR giant ragweed 87%, 88%, 90%, 94%, 96%, 96%, 98%, and 93%, respectively. Halauxifen-methyl and pyroxsulam provided only 45% and 28% control of GR giant ragweed, respectively. Halauxifen-methyl applied alone POST in the spring controlled GR horseweed but not GR giant ragweed in winter wheat.

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Control of Glyphosate-Resistant Giant Ragweed in Winter Wheat

Weed Technology ◽

10.1614/wt-d-15-00028.1 ◽

2015 ◽

Vol 29 (4) ◽

pp. 868-873 ◽

Cited By ~ 4

Author(s):

Kris J. Mahoney ◽

Kristen E. McNaughton ◽

Peter H. Sikkema

Keyword(s):

Population Density ◽

Winter Wheat ◽

Crop Rotation ◽

Weed Management ◽

Aboveground Biomass ◽

Field Experiments ◽

Control Population ◽

Integrated Weed Management ◽

Giant Ragweed ◽

Herbicide Treatments

Four field experiments were conducted over a 2-yr period (2012 and 2013) in winter wheat to evaluate POST herbicides for the control of glyphosate-resistant (GR) giant ragweed. POST herbicides were evaluated for winter wheat injury and GR giant ragweed control, population density, and aboveground biomass. The herbicides used in this study provided 54 to 90% and 51 to 97% control of GR giant ragweed at 4 and 8 wk after treatment (WAT), respectively. At 8 WAT, auxinic herbicide treatments or herbicide tank mix/premix treatments that contained auxinics provided 78 to 97% control of GR giant ragweed. Reductions in GR giant ragweed population density and aboveground biomass were 62 to 100% and 83 to 100%, respectively, and generally reflected the level of control. The results of this research indicate that Ontario, Canada, corn and soybean growers should continue to incorporate winter wheat into their crop rotation as one component of an integrated weed management (IWM) strategy for the control of GR giant ragweed.

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Influence of application timing and herbicide rate on the efficacy of tolpyralate plus atrazine

Weed Technology ◽

10.1017/wet.2019.25 ◽

2019 ◽

Vol 33 (03) ◽

pp. 448-458 ◽

Cited By ~ 1

Author(s):

Brendan A. Metzger ◽

Nader Soltani ◽

Alan J. Raeder ◽

David C. Hooker ◽

Darren E. Robinson ◽

...

Keyword(s):

Weed Management ◽

Field Experiments ◽

Integrated Weed Management ◽

Herbicide Application ◽

Weed Species ◽

Common Ragweed ◽

Application Timing ◽

Common Lambsquarters ◽

Green Foxtail ◽

Equivalent Control

AbstractEffective POST herbicides and herbicide mixtures are key components of integrated weed management in corn; however, herbicides vary in their efficacy based on application timing. Six field experiments were conducted over 2 yr (2017–2018) in southwestern Ontario, Canada, to determine the effects of herbicide application timing and rate on the efficacy of tolpyralate, a new 4-hydroxyphenyl pyruvate dioxygenase inhibitor. Tolpyralate at 15, 30, or 40 g ai ha−1 in combination with atrazine at 500 or 1,000 g ai ha−1 was applied PRE, early POST, mid-POST, or late POST. Tolpyralate + atrazine at rates ≥30 + 1,000 g ha−1 provided equivalent control of common lambsquarters and Powell amaranth applied PRE or POST, whereas no rate applied PRE controlled common ragweed, velvetleaf, barnyardgrass, or green foxtail. Common ragweed, common lambsquarters, velvetleaf, and Powell amaranth were controlled equally regardless of POST timing. In contrast, control of barnyardgrass and green foxtail declined when herbicide application was delayed to the late-POST timing, irrespective of herbicide rate. Similarly, corn grain yield declined within each tolpyralate + atrazine rate when herbicide applications were delayed to late-POST timing. Overall, the results of this study indicate that several monocot and dicot weed species can be controlled with tolpyralate + atrazine with an early to mid-POST herbicide application timing, before weeds reach 30 cm in height, and Powell amaranth and common lambsquarters can also be controlled PRE. Additionally, this study provides further evidence highlighting the importance of effective, early-season weed control in corn.

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Control of glyphosate-resistant horseweed and giant ragweed in soybean with halauxifen-methyl applied preplant

Weed Technology ◽

10.1017/wet.2020.118 ◽

2020 ◽

pp. 1-20

Author(s):

Jessica Quinn ◽

Jamshid Ashigh ◽

Nader Soltani ◽

David C. Hooker ◽

Darren E. Robinson ◽

...

Keyword(s):

United States ◽

Crop Yield ◽

Field Experiments ◽

The United States ◽

Effective Control ◽

Weed Species ◽

Giant Ragweed ◽

Chlorimuron Ethyl ◽

New Challenges ◽

Annual Weeds

Abstract Horseweed and giant ragweed are competitive, annual weeds that can negatively impact crop yield. Biotypes of glyphosate-resistant (GR) giant ragweed and horseweed were first reported in 2008 and 2010 in Ontario, respectively. GR horseweed has spread throughout the southern portion of the province. The presence of GR biotypes poses new challenges for soybean producers in Canada and the United States. Halauxifen-methyl is a recently registered selective herbicide for broadleaf weeds, for preplant use in corn and soybean. There is limited literature on the efficacy of halauxifen-methyl on GR horseweed and giant ragweed when combined with currently registered products in Canada. The purpose of the experiment was to determine the effectiveness of halauxifen-methyl applied alone, and tank-mixed for GR giant ragweed and GR horseweed control in glyphosate and dicamba-resistant (GDR) soybean in southwestern Ontario. Six field experiments were conducted separately for each weed species over 2018 and 2019. Halauxifen-methyl applied alone controlled GR horseweed 72% at 8 weeks after application (WAA). Control was improved to >91% when halauxifen-methyl applied in combination with metribuzin, saflufenacil, chlorimuron-ethyl + metribuzin and saflufenacil + metribuzin. At 8 WAA, halauxifen-methyl controlled GR giant ragweed 11%; glyphosate/2,4-D choline, glyphosate/dicamba, glyphosate/2,4-D choline + halauxifen-methyl and glyphosate/dicamba + halauxifen-methyl controlled GR giant ragweed 76 to 88%. This study concluded that halauxifen-methyl applied preplant in a tank-mixture can provide effective control of GR giant ragweed and horseweed in GDR soybean.

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Giant Foxtail Seed Predation byHarpalus pensylvanicus(Coleoptera: Carabidae)

Weed Science ◽

10.1614/ws-d-14-00010.1 ◽

2014 ◽

Vol 62 (4) ◽

pp. 555-562 ◽

Cited By ~ 6

Author(s):

Meredith J. Ward ◽

Matthew R. Ryan ◽

William S. Curran ◽

Jeffrey Law

Keyword(s):

Weed Management ◽

Management Practices ◽

Field Experiments ◽

The United States ◽

Future Research ◽

Weed Species ◽

Common Lambsquarters ◽

Giant Foxtail ◽

Seed Preference ◽

Activity Density

The utility of biological control for weed management in agroecosystems will increase with a greater understanding of the relationships between common weed and granivore species. Giant foxtail is an introduced, summer annual grass weed that is common throughout the United States and problematic in numerous crops.Harpalus pensylvanicus(DeGeer) (Coleoptera: Carabidae) is a common, native, omnivorous carabid beetle with a range that overlaps giant foxtail. In 2004 and 2005,H. pensylvanicuswas captured from farm fields in Centre County, PA, and subjected to laboratory feeding trials to test the preference of giant foxtail and other species on predation byH. pensylvanicus. Weed species seed preference experiments that included “Choice” and “No Choice” treatments were conducted using giant foxtail, common lambsquarters, and velvetleaf. When given a choice amongst the three weed species,H. pensylvanicuspreferred giant foxtail and common lambsquarters seeds equally compared to velvetleaf seeds. When given the choice,H. pensylvanicuspreferred newly dispersed giant foxtail seeds over field-aged seeds. Phenology of giant foxtail seed shed relative toH. pensylvanicusactivity density was also quantified in field experiments in 2005 and 2006. Giant foxtail seed rain was determined by collecting shed seeds from August through October using pan traps. Activity density ofH. pensylvanicuswas monitored for 72-h periods using pitfall traps from June to October. Peak activity density ofH. pensylvanicusoccurred at the onset of giant foxtail seed shed in both years; however, giant foxtail seed shed peaked approximately 30 to 50 d afterH. pensylvanicusactivity density. Future research should focus on management practices that enhance and supportH. pensylvanicuspopulations later in the growing season to maximize suppression of giant foxtail and other weeds that shed palatable seeds later in the season.

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Management of Italian Ryegrass (Lolium perennessp.multiflorum) in Western Oregon with Preemergence Applications of Pyroxasulfone in Winter Wheat

Weed Technology ◽

10.1614/wt-d-11-00059.1 ◽

2012 ◽

Vol 26 (2) ◽

pp. 230-235 ◽

Cited By ~ 23

Author(s):

Andrew G. Hulting ◽

Joseph T. Dauer ◽

Barbara Hinds-Cook ◽

Daniel Curtis ◽

Rebecca M. Koepke-Hill ◽

...

Keyword(s):

Winter Wheat ◽

Pacific Northwest ◽

Field Experiments ◽

Cropping Systems ◽

Wheat Yield ◽

The United States ◽

Italian Ryegrass ◽

Weed Species ◽

Application Rates ◽

Grass Weed

Management of Italian ryegrass in cereal-based cropping systems continues to be a major production constraint in areas of the United States, including the soft white winter wheat producing regions of the Pacific Northwest. Pyroxasulfone is a soil-applied herbicide with the potential to control broadleaf and grass weed species, including grass weed biotypes resistant to group 1, 2, and 7 herbicides, in several crops for which registration has been completed or is pending, including wheat, corn, sunflower, dry bean, and soybean. Field experiments were conducted from 2006 through 2009 near Corvallis, OR, to evaluate the potential for Italian ryegrass control in winter wheat with applications of pyroxasulfone. Application rates of PRE treatments ranged from 0.05 to 0.15 kg ai ha−1. All treatments were compared to standard Italian ryegrass soil-applied herbicides used in winter wheat, including diuron, flufenacet, and flufenacet + metribuzin. Visual evaluations of Italian ryegrass and ivyleaf speedwell control and winter wheat injury were made at regular intervals following applications. Winter wheat yields were quantified at grain maturity. Ivyleaf speedwell control was variable, and Italian ryegrass control following pyroxasulfone applications ranged from 65 to 100% and was equal to control achieved with flufenacet and flufenacet + metribuzin treatments and greater than that achieved with diuron applications. Winter wheat injury from pyroxasulfone ranged from 0 to 8% and was most associated with the 0.15–kg ha−1application rate. However, this early-season injury did not negatively impact winter wheat yield. Pyroxasulfone applied at the application rates and timings in these studies resulted in high levels of activity on Italian ryegrass and excellent winter wheat safety. Based on the results, pyroxasulfone has the potential to be used as a soil-applied herbicide in winter wheat for Italian ryegrass management and its utility for management of other important grass and broadleaf weeds of cereal-based cropping systems should be evaluated.

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Assessment of weed and crop fitness in cover crop residues for integrated weed management

Weed Science ◽

10.1017/s0043174500091153 ◽

1998 ◽

Vol 46 (5) ◽

pp. 595-603 ◽

Cited By ~ 52

Author(s):

Martin M. Williams ◽

David A. Mortensen ◽

John W. Doran

Keyword(s):

Weed Control ◽

Weed Management ◽

Cover Crop ◽

Field Experiments ◽

Crop Residues ◽

Seedling Emergence ◽

Integrated Weed Management ◽

Weed Species ◽

Weed Growth ◽

Canopy Volume

Cover crop residues are not widely used for weed control because, as a stand-alone tactic, they do not effectively suppress all weeds and their duration of weed control is too short. Field experiments were conducted in 1995 and 1996, under both irrigated and rainfed conditions, to quantifyAmaranthusspp.,Setariaspp., and soybean emergence and growth in residues of fall-planted, spring-killed barley, rye, triticale, wheat, and hairy vetch. For both weed species, seedling emergence was reduced 3 wk after soybean planting by rye and wheat residues (≥ 2, 170 kg ha−1) in 1996. In 1996,Amaranthusspp. canopy volume was reduced 38 to 71% by residues 3 wk after planting. Likewise,Setariaspp. canopy biomass was reduced 37 to 97% in residues 5 wk after planting over both years. The response comparison index was used to identify frequency by which weed growth was placed at a disadvantage relative to soybean growth.Amaranthusspp. andSetariaspp. growth suppressions 3 to 5 wk after planting indicate potential times for intervention with other integrated weed management tactics such as reduced postemergence herbicide rates and interrow cultivation.

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Glyphosate-Resistant Giant Ragweed (Ambrosia trifida) Control in Glufosinate-Resistant Soybean

Weed Technology ◽

10.1614/wt-d-14-00009.1 ◽

2014 ◽

Vol 28 (4) ◽

pp. 569-577 ◽

Cited By ~ 25

Author(s):

Simranpreet Kaur ◽

Lowell D. Sandell ◽

John L. Lindquist ◽

Amit J. Jhala

Keyword(s):

Field Experiments ◽

Crop Yields ◽

The United States ◽

Early Spring ◽

Ambrosia Trifida ◽

Soybean Field ◽

Agronomic Crops ◽

Giant Ragweed ◽

Rapid Growth Rate

Glyphosate-resistant giant ragweed is one of the most competitive weeds of agronomic crops in the United States. Early emergence and rapid growth rate makes giant ragweed a competitive weed early in the season and reduces crop yields. Therefore, early spring control of giant ragweed using a preplant herbicide is critical. Glufosinate is an alternative POST herbicide for weed control in glufosinate-resistant soybean. Field experiments were conducted at David City, NE, in 2012 and 2013 to evaluate the efficacy of preplant herbicides followed by glufosinate applied alone or in tank mixes for control of glyphosate-resistant giant ragweed in glufosinate-resistant soybean. Preplant treatments containing 2,4-D, flumioxazin, glufosinate, paraquat, saflufenacil, and sulfentrazone provided 79 to 99% control of giant ragweed 21 d after treatment (DAT), and subsequent application of glufosinate alone or in tank mixes resulted in 90 to 99% control at 21 DAT. Preplant application ofS-metolachlor plus metribuzin or chlorimuron, flumioxazin plus thifensulfuron followed by glufosinate resulted in < 40% control of giant ragweed, and soybean yields were < 870 kg ha−1. Although statistically comparable to several other treatments, preplant application of 2,4-D or saflufenacil tank mixes followed by glufosinate resulted in the highest level of control (> 97%) and soybean yield (2,624 to 3,378 kg ha−1). This study confirms that preplant herbicide options are available for control of glyphosate-resistant giant ragweed, and a follow-up application of glufosinate will provide season-long control in glufosinate-resistant soybean.

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Ambrosia trifida L.: Giant ragweed

Acta herbologica ◽

10.5937/actaherb2101005v ◽

2021 ◽

Vol 30 (1) ◽

pp. 5-18

Author(s):

Sava Vrbničanin

Keyword(s):

Environmental Conditions ◽

Management Practices ◽

Animal Feed ◽

Acetolactate Synthase ◽

Control Measures ◽

Integrated Weed Management ◽

Weed Species ◽

Row Crops ◽

Ambrosia Trifida ◽

Giant Ragweed

Ambrosia trifida L. (AMBTR, fam. Asteraceae/Compositae) is native to North America. It was introduced accidentally to Europe at the end of the 19th century, with contaminated animal feed and seeds for planting. Today A. trifida is present in ruderal and agricultural habitats of many European countries (France, Italy, Germany, Russia, Spain, Romania, Slovakia, Czech Republic, Poland, Serbia, Bulgaria, etc.). Giant ragweed was detected for the first time in 1981 in Serbia (site Čoka). Over the following period it disappeared from this site, but was recorded again in 2006 in another site (central Bačka: Despotovo, Kucura, Savino Selo, Ravno Selo, Ruski Krstur). Currently in Serbia it has the status of an alien naturalized weed species. This summer annual plant can grow up to 6 m in height and exhibits a high degree of morphological and reproductive plasticity in response to encroachment by neighboring plants. It is present in disturbed habitats, such as agriculture fields, where it plays the role of the dominant species throughout the entire growing season. In most cases, leaves are opposite and always simple and generally have 3 distinct lobes but can also have as many as 5. It is a diploid (2n = 24), meso-hygrophilic species, preferring wet habitatse and can tolerate a wide variety of soil types. Also, this is a monoecious plant, where male and female flowers are separated on the same individual. A. trifida can hybridise with A. artemisiifolia (A. x helenae Rouleau, with 2n= 27 and 2n= 33), but this hybrid has been described as sterile. Compared to other summer annual species, A. trifida is among the first to emerge in early spring, at optimal temperatures from 10-24°C. Under optimal environmental conditions, giant ragweed produces around 1,800 (max 5,100) seeds plant-1. It flowers and bears fruit from July to September (October).The pollen of this species has allergenic potential. Additionally, in the USA and Canada giant ragweed populations have developed resistance to acetolactate synthase inhibitor herbicides and glyphosate. Giant ragweed can be a problematic weed in row crops (corn, soybean, sunflower, sugerbeet) and vegetables. In A. trifida the control measures should prevent further spread, and existing populations should be controlled by integrated weed management practices. Furthermore, A. trifida has a relatively low fecundity, a transient soil seedbank and a high percentage of non-viable or low-survivorship seeds, which are features that may have constrained its establishment and spread in the current environmental conditions in Serbia.

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Glyphosate-Resistant Giant Ragweed (Ambrosia trifida) and Waterhemp (Amaranthus rudis) Management in Dicamba-Resistant Soybean (Glycine max)

Weed Technology ◽

10.1614/wt-d-13-00091.1 ◽

2014 ◽

Vol 28 (1) ◽

pp. 131-141 ◽

Cited By ~ 20

Author(s):

Douglas J. Spaunhorst ◽

Simone Siefert-Higgins ◽

Kevin W. Bradley

Keyword(s):

Glycine Max ◽

Field Experiments ◽

Treatment Delay ◽

Weed Species ◽

Ambrosia Trifida ◽

Density Reduction ◽

Giant Ragweed ◽

Herbicide Treatments ◽

Amaranthus Rudis ◽

Integrated Program

Field experiments were conducted across two locations during 2011 and 2012 to evaluate herbicide options for the control of glyphosate-resistant (GR) giant ragweed and GR waterhemp in dicamba-resistant (DR) soybean. All herbicide treatments provided 91 to 100% control of GR giant ragweed 3 wk after treatment (WAT). Flumioxazin plus dicamba plus glyphosate applied preplant provided greater control and density reduction of GR giant ragweed than flumioxazin plus 2,4-D plus glyphosate. When flumioxazin plus dicamba plus glyphosate were applied preplant, the addition of dicamba to glyphosate at either the early-postemergence (EPOST) or mid-postemergence (MPOST) timing provided greater control and density reduction of GR giant ragweed than glyphosate alone. Regardless of the preplant treatment, delay of EPOST dicamba to the MPOST timing did not influence GR giant ragweed control or density reduction. In the GR waterhemp experiment, dicamba plus glyphosate applied sequentially provided 88 to 89% control and 90% density reduction at the EPOST and MPOST timings compared to only 24% control and 42% density reduction in response to glyphosate applied sequentially. Control and GR waterhemp density reduction did not improve with the addition of acetochlor to either the EPOST or late-postemergence (LPOST) timings. Flumioxazin plus chlorimuron applied PRE followed by dicamba plus glyphosate or dicamba plus glyphosate plus acetochlor provided greater control of GR waterhemp than glyphosate plus fomesafen or glyphosate alone applied EPOST. Results from this research indicate that dicamba applied once or sequentially and when timed appropriately to match the biology of the weed species can be utilized as a component of an integrated program for the management of GR weeds like giant ragweed and waterhemp in DR soybean.

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Interaction of Preventive, Cultural, and Direct Methods for Integrated Weed Management in Winter Wheat

Agronomy ◽

10.3390/agronomy9090564 ◽

2019 ◽

Vol 9 (9) ◽

pp. 564 ◽

Cited By ~ 2

Author(s):

Alexander Menegat ◽

Anders T. S. Nilsson

Keyword(s):

Winter Wheat ◽

Weed Control ◽

Weed Management ◽

Field Experiments ◽

Integrated Weed Management ◽

Wheat Seed ◽

Control Efficacy ◽

Seed Rate ◽

Alopecurus Myosuroides ◽

Seedbed Preparation

Crop rotations dominated by winter annual crops and relying on the use of herbicides to control weeds have resulted in weed communities dominated by a few highly specialized species such as Alopecurus myosuroides. Integrated weed management (IWM) represents a sensible strategy to target such difficult weeds, through a combination of preventive, cultural, and direct means. In six field trials over three years, we tested the effect of stale seedbed preparation, winter wheat seed rate, and chemical weed control strategy on Alopecurus myosuroides control efficacy and variability in efficacy. The field experiments were carried out under reduced tillage practice and without pre-sowing use of glyphosate. Stale seedbed preparation alone reduced A. myosuroides infestation level by 25% on average. No clear effect was found of increasing winter wheat seed rate from 300 to 400 seeds m−2. A combination of stale seedbed preparation and herbicide treatment in autumn and spring was found to be synergistic, improving weed control efficacy significantly and moreover reducing the variability in control efficacy and hence the risk for weed control failure.

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