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

2014 ◽  
Vol 28 (1) ◽  
pp. 131-141 ◽  
Author(s):  
Douglas J. Spaunhorst ◽  
Simone Siefert-Higgins ◽  
Kevin W. Bradley

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.

1992 ◽  
Vol 6 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Jerry A. Baysinger ◽  
Barry D. Sims

Two field experiments were established in 1988 and 1989 in southeast Missouri to evaluate several herbicides and herbicide combinations for giant ragweed control in soybean. In 1988, a timely rainfall was not received for soil-applied herbicides and giant ragweed control was less than 75%. However, in 1989 soil moisture was sufficient for uptake of soil-applied herbicides and early season giant ragweed control was generally greater than 80%. Chlorimuron, chlorimuron plus 2,4-DB, imazaquin plus 2,4-DB, acifluorfen followed by naptalam plus 2,4-DB, fomesafen, and imazethapyr applied to 2.5 to 5-cm giant ragweed controlled more than 85% in 1988. In 1989, all POST treatments except imazaquin controlled more than 81% of giant ragweed 2 wk after treatments. Imazethapyr controlled seedling giant ragweed at heights up to 12 to 25 cm. Giant ragweed regrowth and/or reinfestation and giant ragweed seed production occurred with all herbicide treatments.


2020 ◽  
Vol 34 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Jessica Quinn ◽  
Nader Soltani ◽  
Jamshid Ashigh ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  

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.


1999 ◽  
Vol 13 (4) ◽  
pp. 825-828 ◽  
Author(s):  
Rebecca J. Franey ◽  
Stephen E. Hart

Field experiments were conducted at Dekalb, IL, in 1996 and 1997 to determine the optimum application timing and rate of cloransulam for giant ragweed (Ambrosia trifida) control in soybean (Glycine max). Cloransulam treatments included preplant incorporated (PPI) and preemergence (PRE) applications of 35 g ai/ha and early postemergence (EPOST), postemergence (POST), and late postemergence (LPOST) applications of 18 or 27 g ai/ha. Cloransulam applied at 18 g/ha was also combined with lactofen at 70 g ai/ha at each POST application timing. At 60 d after LPOST, cloransulam applied PPI provided 68% giant ragweed control in 1996 and 1997 compared to PRE applications, which provided 95 and 25% giant ragweed control, respectively. The reduction in giant ragweed control with PRE applications of cloransulam in 1997 was likely due to insufficient rainfall for activation. Cloransulam applied at 18 g/ha EPOST provided 87 and 88% giant ragweed control, respectively, in 1996 and 1997. Cloransulam applied POST provided 97 and 82% giant ragweed control, respectively, in successive years. Delaying cloransulam application until LPOST reduced giant ragweed control to 53 and 47%, respectively, in 1996 and 1997 compared to EPOST and POST. At EPOST and POST application timings, increasing the rate of cloransulam to 27 g/ha or adding lactofen did not improve giant ragweed control. However, giant ragweed control was improved by at least 20% by increasing the rate of cloransulam to 27 g/ha at LPOST. Similarly, applying cloransulam in combination with lactofen improved giant ragweed control by at least 15% at LPOST.


Weed Science ◽  
1991 ◽  
Vol 39 (3) ◽  
pp. 358-362 ◽  
Author(s):  
Jerry A. Baysinger ◽  
Barry D. Sims

Field experiments were established near Portageville, MO, to determine the effects of giant ragweed interference in soybeans. Threshold densities of giant ragweed that reduced soybean yield were less than two plants 9 m−1of soybean row. This density reduced soybean seed yield 46 and 50% in 1988 and 1989, respectively, after full-season interference. The critical duration of giant ragweed interference in soybeans was between 4 and 6 weeks after emergence (WAE) in 1988 and between 2 and 4 WAE in 1989. Full-season giant ragweed interference at densities of 220 000 and 360 000 plants ha−1in 1988 and 1989, respectively, resulted in almost complete soybean yield loss. Eight to 10 weeks after emergence of giant ragweed-free conditions were required to prevent soybean yield reductions.


Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 262
Author(s):  
Matt Liebman ◽  
Virginia A. Nichols

Weeds present important challenges to both conventional farmers who rely on herbicides and organic farmers who rely on cultivation. Data from field experiments indicate that diversifying crop sequences with additional species can improve weed suppression when either herbicides or cultivation serve as primary control tactics. Here, we report the results of modeling analyses that investigated how cropping system diversification would affect the population dynamics of giant ragweed (Ambrosia trifida L.), an annual dicotyledonous species that is problematic in the central U.S. for both conventional and organic farmers. We found that to prevent an increase in giant ragweed density, the minimum control efficacy needed from herbicides or cultivation used in corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) would be 99.0% in a 2-year corn–soybean system, but 91.4% in a 5-year corn–soybean–rye (Secale cereale L.)–alfalfa (Medicago sativa L.) system. Thus, the diversified rotation would be better buffered against less-than-perfect weed control during corn and soybean phases. Further modeling analyses indicated that the weed suppression effect associated with greater rotation length was attributable not only to increased crop species richness but also to greater temporal variation in planting dates. A planting interval variation index (PIVI), calculated as the coefficient of variation in months between planting activities, was strongly associated with the weed suppressive ability of the rotations we modeled and may be a useful metric for designing other cropping systems. Overall, our results indicate that diversified rotation systems that include both annual and perennial crops are likely to be valuable for managing problematic weed species.


1994 ◽  
Vol 8 (4) ◽  
pp. 840-848 ◽  
Author(s):  
Chester L. Foy ◽  
Susan B. Harrison ◽  
Harold L. Witt

Field experiments were conducted at two locations in Virginia to evaluate the following herbicides: alachlor, diphenamid, diuron, metolachlor, napropamide, norflurazon, oryzalin, oxyfluorfen, paraquat, pendimethalin, and simazine. One experiment involved newly-transplanted apple trees; the others, three in apple and one in peach trees, involved one-year-old trees. Treatments were applied in the spring (mid-April to early-May). Control of annual weed species was excellent with several treatments. A broader spectrum of weeds was controlled in several instances when the preemergence herbicides were used in combinations. Perennial species, particularly broadleaf species and johnsongrass, were released when annual species were suppressed by the herbicides. A rye cover crop in nontreated plots suppressed the growth of weeds. New shoot growth of newly-transplanted apple trees was increased with 3 of 20 herbicide treatments and scion circumference was increased with 11 of 20 herbicide treatments compared to the nontreated control. Growth of one-year-old apple trees was not affected. Scion circumference of one-year-old peach trees was increased with 25 of 33 herbicide treatments.


2013 ◽  
Vol 27 (3) ◽  
pp. 454-458 ◽  
Author(s):  
Kelly A. Barnett ◽  
Thomas C. Mueller ◽  
Lawrence E. Steckel

The development of crops resistant to 2,4-D, dicamba, and glufosinate may provide new options for the management of glyphosate-resistant (GR) giant ragweed and other herbicide-resistant weeds. A fallow field study was conducted in 2011 and 2012 to determine the control of GR giant ragweed with 2,4-D and dicamba applied alone and in combination with glufosinate or fomesafen. Dicamba and 2,4-D tank-mixed with glufosinate or fomesafen provided the highest level of control at 10 or 20 days after application (DAA). At 30 DAA, all herbicide treatments provided > 88% control of giant ragweed except glyphosate, glufosinate, and 2,4-D alone at 0.56 kg ae ha−1. Glyphosate, glufosinate, and 2,4-D alone at 0.56 kg ae ha−1also had the highest number of giant ragweed plants (> 5.8 plants m−2) and highest biomass (> 19.2 g m−2). Contrast statements between 2,4-D and dicamba indicated no differences among treatments containing these herbicides. However, contrast analysis indicated that herbicides applied alone resulted in 56, 58, and 61% control while tank-mix combinations of 2,4-D or dicamba with glufosinate or fomesafen resulted in 86, 91, and 93% control, respectively. Herbicides applied alone also had more giant ragweed plants and biomass per m−2than herbicides applied in tank-mix combinations. Tank-mixing combinations of 2,4-D and dicamba will be important for effective control of GR giant ragweed.


2015 ◽  
Vol 29 (4) ◽  
pp. 771-781 ◽  
Author(s):  
R. Joseph Wuerffel ◽  
Julie M. Young ◽  
Joseph L. Matthews ◽  
Vince M. Davis ◽  
William G. Johnson ◽  
...  

Fall-applied residual and spring preplant burn-down herbicide applications are typically used to control winter annual weeds and may also provide early-season residual control of summer annual weed species such as giant ragweed. Field experiments were conducted from 2006 to 2008 in southern Illinois to (1) assess the emergence pattern of giant ragweed, (2) evaluate the efficacy of several herbicides commonly used for soil-residual control of giant ragweed, and (3) investigate the optimal application timing of soil-residual herbicides for control of giant ragweed. Six herbicide treatments were applied at four application timings: early fall, late fall, early spring, and late spring. Giant ragweed first emerged in mid- and late-March in 2007 and 2008, respectively. The duration of emergence varied by year, with 95% of emergence complete in late May of 2008, but not until early July in 2007. Giant ragweed emergence occurred more quickly in plots that received a fall application of glyphosate + 2,4-D compared with the nontreated. Fall-applied residual herbicides did not reduce giant ragweed emergence in 2007 when compared with the nontreated, with the exception of chlorimuron + tribenuron applied in late fall. Giant ragweed control from early- and late-spring herbicide applications was variable by year. In 2007, saflufenacil (50 and 100 g ai ha−1) and simazine applied in early spring reduced giant ragweed densities by 95% or greater through mid-May; however, in 2008, early-spring applications failed to reduce giant ragweed emergence in mid-April. The only treatments that reduced giant ragweed densities by > 80% through early July were late-spring applications of chlorimuron + tribenuron or saflufenacil at 100 g ha−1. Thus, the emergence patterns of giant ragweed in southern Illinois dictates that best management with herbicides would include late-spring applications of soil-residual herbicides just before crop planting and most likely requires subsequent control with foliar or soil-residual herbicides after crop emergence.


2015 ◽  
Vol 29 (4) ◽  
pp. 868-873 ◽  
Author(s):  
Kris J. Mahoney ◽  
Kristen E. McNaughton ◽  
Peter H. Sikkema

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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