Herbicide systems including linuron for Palmer amaranth (Amaranthus palmeri) control in sweetpotato

2020 ◽  
pp. 1-8
Author(s):  
Levi D. Moore ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Michael D. Boyette ◽  
David L. Jordan ◽  
...  
Keyword(s):  
Weed Control ◽  
Field Studies ◽  
Palmer Amaranth ◽  
Management Systems ◽  
Amaranthus Palmeri ◽  
Marketable Yield ◽  
Time Of Application ◽  
Weed Interference

Abstract Field studies were conducted to determine sweetpotato tolerance to and weed control from management systems that included linuron. Treatments included flumioxazin preplant (107 g ai ha−1) followed by (fb) S-metolachlor (800 g ai ha−1), oryzalin (840 g ai ha−1), or linuron (280, 420, 560, 700, and 840 g ai ha−1) alone or mixed with S-metolachlor or oryzalin applied 7 d after transplanting. Weeds did not emerge before the treatment applications. Two of the four field studies were maintained weed-free throughout the season to evaluate sweetpotato tolerance without weed interference. The herbicide program with the greatest sweetpotato yield was flumioxazin fb S-metolachlor. Mixing linuron with S-metolachlor did not improve Palmer amaranth management and decreased marketable yield by up to 28% compared with flumioxazin fb S-metolachlor. Thus, linuron should not be applied POST in sweetpotato if Palmer amaranth has not emerged at the time of application.

Safety and efficacy of linuron with or without an adjuvant or S-metolachlor for POST control of Palmer amaranth (Amaranthus palmeri) in sweetpotato

2021 ◽  
pp. 1-18
Author(s):  
Levi D. Moore ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Ramon G. Leon ◽  
David L. Jordan ◽  
...  
Keyword(s):  
Nonionic Surfactant ◽  
Weed Control ◽  
Critical Period ◽  
Total Yield ◽  
Field Studies ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Foliar Injury ◽  
Protoporphyrinogen Oxidase ◽  
Safety And Efficacy

Abstract Field studies were conducted to evaluate linuron for POST control of Palmer amaranth in sweetpotato to minimize reliance on protoporphyrinogen oxidase (PPO)-inhibiting herbicides. Treatments were arranged in a two by four factorial where the first factor consisted of two rates of linuron (420 and 700 g ai ha−1), and the second factor consisted of linuron applied alone or in combinations of linuron plus a nonionic surfactant (NIS) (0.5% v/v), linuron plus S-metolachlor (800 g ai ha−1), or linuron plus NIS plus S-metolachlor. In addition, S-metolachlor alone and nontreated weedy and weed-free checks were included for comparison. Treatments were applied to ‘Covington’ sweetpotato 8 d after transplanting (DAP). S-metolachlor alone provided poor Palmer amaranth control because emergence had occurred at applications. All treatments that included linuron resulted in at least 98 and 91% Palmer amaranth control 1 and 2 wk after treatment (WAT), respectively. Including NIS with linuron did not increase Palmer amaranth control compared to linuron alone, but increased sweetpotato injury and subsequently decreased total sweetpotato yield by 25%. Including S-metolachlor with linuron resulted in the greatest Palmer amaranth control 4 WAT, but increased crop foliar injury to 36% 1 WAT compared to 17% foliar injury from linuron alone. Marketable and total sweetpotato yield was similar between linuron alone and linuron plus S-metolachlor or S-metolachlor plus NIS treatments, though all treatments resulted in at least 39% less total yield than the weed-free check resulting from herbicide injury and/or Palmer amaranth competition. Because of the excellent POST Palmer amaranth control from linuron 1 WAT, a system including linuron applied 7 DAP followed by S-metolachlor applied 14 DAP could help to extend residual Palmer amaranth control further into the critical period of weed control while minimizing sweetpotato injury.

Critical Period for Palmer Amaranth (Amaranthus palmeri) Control in Pickling Cucumber

2018 ◽  
Vol 32 (5) ◽  
pp. 586-591
Author(s):  
Samuel J. McGowen ◽  
Katherine M. Jennings ◽  
Sushila Chaudhari ◽  
David W. Monks ◽  
Jonathan R. Schultheis ◽  
...  
Keyword(s):  
North Carolina ◽  
Critical Period ◽  
Relative Yield ◽  
Field Studies ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Marketable Yield ◽  
Yield Data ◽  
Pickling Cucumber ◽  
Cucumber Yield

AbstractField studies were conducted in North Carolina to determine the critical period for Palmer amaranth control (CPPAC) in pickling cucumber. In removal treatments (REM), emerged Palmer amaranth were allowed to compete with cucumber for 14, 21, 28, or 35 d after sowing (DAS) in 2014 and 14, 21, 35, or 42 DAS in 2015, and cucumber was kept weed-free for the remainder of the season. In the establishment treatments (EST), cucumber was maintained free of Palmer amaranth by hand removal until 14, 21, 28, or 35 DAS in 2014 and until 14, 21, 35, or 42 DAS in 2015; after this, Palmer amaranth was allowed to establish and compete with the cucumber for the remainder of the season. The beginning and end of the CPPAC, based on 5% loss of marketable yield, was determined by fitting log-logistic and Gompertz equations to the relative yield data representing REM and EST, respectively. Season-long competition by Palmer amaranth reduced pickling cucumber yield by 45% to 98% and 88% to 98% during 2014 and 2015, respectively. When cucumber was planted on April 25, 2015, the CPPAC ranged from 570 to 1,002 heat units (HU), which corresponded to 32 to 49 DAS. However, when cucumber planting was delayed 2 to 4 wk (May 7 and May 21, 2014 and May 4, 2015), the CPPAC lasted from 100 to 918 HU (7 to 44 DAS). This research suggested that planting pickling cucumber as early as possible during the season may help to reduce competition by Palmer amaranth and delay the beginning of the CPPAC.

Critical timing of Palmer amaranth (Amaranthus palmeri) removal in sweetpotato

2020 ◽  
Vol 34 (4) ◽  
pp. 547-551 ◽  
Author(s):  
Stephen C. Smith ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Sushila Chaudhari ◽  
Jonathan R. Schultheis ◽  
...  
Keyword(s):  
North Carolina ◽  
Logistic Model ◽  
Yield Loss ◽  
Relative Yield ◽  
Field Studies ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Marketable Yield ◽  
Yield Data ◽  
Critical Timing

AbstractPalmer amaranth is the most common and troublesome weed in North Carolina sweetpotato. Field studies were conducted in Clinton, NC, in 2016 and 2017 to determine the critical timing of Palmer amaranth removal in ‘Covington’ sweetpotato. Palmer amaranth was grown with sweetpotato from transplanting to 2, 3, 4, 5, 6, 7, 8, and 9 wk after transplanting (WAP) and maintained weed-free for the remainder of the season. Palmer amaranth height and shoot dry biomass increased as Palmer amaranth removal was delayed. Season-long competition by Palmer amaranth interference reduced marketable yields by 85% and 95% in 2016 and 2017, respectively. Sweetpotato yield loss displayed a strong inverse linear relationship with Palmer amaranth height. A 0.6% and 0.4% decrease in yield was observed for every centimeter of Palmer amaranth growth in 2016 and 2017, respectively. The critical timing for Palmer amaranth removal, based on 5% loss of marketable yield, was determined by fitting a log-logistic model to the relative yield data and was determined to be 2 WAP. These results show that Palmer amaranth is highly competitive with sweetpotato and should be managed as early as possible in the season. The requirement of an early critical timing of weed removal to prevent yield loss emphasizes the importance of early-season scouting and Palmer amaranth removal in sweetpotato fields. Any delay in removal can result in substantial yield reductions and fewer premium quality roots.

Weed management with CGA-362622 in transgenic and nontransgenic cotton

Weed Science ◽  
2003 ◽  
Vol 51 (6) ◽  
pp. 1002-1009 ◽  
Author(s):  
Dunk Porterfield ◽  
John W. Wilcut ◽  
Jerry W. Wells ◽  
Scott B. Clewis
Keyword(s):  
North Carolina ◽  
Weed Control ◽  
Weed Management ◽  
Field Studies ◽  
Palmer Amaranth ◽  
Management Systems ◽  
Weed Species ◽  
Crop Tolerance ◽  
Prickly Sida ◽  
Smooth Pigweed

Field studies conducted at three locations in North Carolina in 1998 and 1999 evaluated crop tolerance, weed control, and yield with CGA-362622 alone and in combination with various weed management systems in transgenic and nontransgenic cotton systems. The herbicide systems used bromoxynil, CGA-362622, glyphosate, and pyrithiobac applied alone early postemergence (EPOST) or mixtures of CGA-362622 plus bromoxynil, glyphosate, or pyrithiobac applied EPOST. Trifluralin preplant incorporated followed by (fb) fluometuron preemergence (PRE) alone or fb a late POST–directed (LAYBY) treatment of prometryn plus MSMA controlled all the weed species present less than 90%. Herbicide systems that included soil-applied and LAYBY herbicides plus glyphosate EPOST or mixtures of CGA-362622 EPOST plus bromoxynil, glyphosate, or pyrithiobac controlled broadleaf signalgrass, entireleaf morningglory, large crabgrass, Palmer amaranth, prickly sida, sicklepod, and smooth pigweed at least 90%. Only cotton treated with these herbicide systems yielded equivalent to the weed-free check for each cultivar. Bromoxynil systems did not control Palmer amaranth and sicklepod, pyrithiobac systems did not control sicklepod, and CGA-362622 systems did not control prickly sida.

scholarly journals Weed Control and Peanut Tolerance with Ethalfluralin-Based Herbicide Systems

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
W. J. Grichar ◽  
P. A. Dotray
Keyword(s):  
Weed Control ◽  
Arachis Hypogaea ◽  
Field Studies ◽  
Palmer Amaranth ◽  
Tribulus Terrestris ◽  
Amaranthus Palmeri ◽  
Cyperus Esculentus ◽  
Yellow Nutsedge ◽  
Devil’S Claw ◽  
Herbicide Treatments

Field studies were conducted from 2007 through 2009 to determine weed efficacy and peanut (Arachis hypogaeaL.) response to herbicide systems that included ethalfluralin applied preplant incorporated. Control of devil's claw (Proboscidea louisianica(Mill.) Thellung), yellow nutsedge (Cyperus esculentusL.), Palmer amaranth (Amaranthus palmeriS. Wats.), and puncturevine (Tribulus terrestrisL.) was most consistent with ethalfluralin followed by either imazapic or imazethapyr applied postemergence. Peanut stunting was 19% when paraquat alone was applied early-postemergence. Stunting increased to greater than 30% when ethalfluralin applied preplant incorporated was followed byS-metolachlor applied preemergence and paraquat applied early-postemergence. Stunting (7%) was also observed when ethalfluralin was followed by flumioxazin plusS-metolachlor applied preemergence with lactofen applied mid-postemergence. Ethalfluralin followed by paraquat applied early-postemergence reduced peanut yield when compared to the nontreated check. Ethalfluralin applied preplant incorporated followed by imazapic applied mid-postemergence provided the greatest yield (6220 kg/ha). None of the herbicide treatments reduced peanut grade (sound mature kernels plus sound splits) when compared with the nontreated check.

Effect of bicyclopyrone herbicide on sweetpotato and Palmer amaranth (Amaranthus palmeri)

2020 ◽  
Vol 34 (4) ◽  
pp. 552-559
Author(s):  
Jennifer J. Lindley ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Sushila Chaudhari ◽  
Jonathan R. Schultheis ◽  
...  
Keyword(s):  
Dry Weight ◽  
Field Studies ◽  
Palmer Amaranth ◽  
Yield Reduction ◽  
Amaranthus Palmeri ◽  
Marketable Yield ◽  
Management Options ◽  
Application Timing ◽  
Shoot Dry Weight ◽  
Plant Injury

AbstractManagement options are needed to limit sweetpotato yield loss due to weeds. Greenhouse studies were conducted in 2018 in Greensboro, NC, and in the field from 2016 to 2018 in Clinton, NC, to evaluate the effect of bicyclopyrone on sweetpotato and Palmer amaranth (field only). In greenhouse studies, Covington and NC04-531 clones were treated with bicyclopyrone (0, 25, 50, 100, or 150 g ai ha−1) either preplant (PP; i.e., immediately before transplanting) or post-transplant (PT; i.e., on the same day after transplanting). Sweetpotato plant injury and stunting increased, and vine length and shoot dry weight decreased with increasing rate of bicyclopyrone regardless of clone or application timing. In field studies, Beauregard (2016) or Covington (2017 and 2018) sweetpotato clones were treated with bicyclopyrone at 50 g ha−1 PP, flumioxazin at 107 g ai ha−1 PP, bicyclopyrone at 50 or 100 g ha−1 PP followed by (fb) S-metolachlor at 800 g ai ha−1 PT, flumioxazin at 107 g ha−1 PP fb S-metolachlor at 800 g ha−1 PT, flumioxazin at 107 g ha−1 PP fb S-metolachlor at 800 g ha−1 PT fb bicyclopyrone at 50 g ha−1 PT-directed, and clomazone at 420 g ai ha−1 PP fb S-metolachlor at 800 g ha−1 PT. Bicyclopyrone PP at 100 g ha−1 fb S-metolachlor PT caused 33% or greater crop stunting and 44% or greater marketable yield reduction compared with the weed-free check in 2016 (Beauregard) and 2017 (Covington). Bicyclopyrone PP at 50 g ha−1 alone or fb S-metolachlor PT resulted in 12% or less injury and similar no. 1 and jumbo yields as the weed-free check in 2 of 3 yr. Injury to Covington from bicyclopyrone PT-directed was 4% or less at 4 or 5 wk after transplanting and marketable yield was similar to that of the weed-free check in 2017 and 2018.

Palmer Amaranth (Amaranthus palmeri) Control by Glufosinate plus Fluometuron Applied Postemergence to WideStrike®Cotton

2013 ◽  
Vol 27 (2) ◽  
pp. 291-297 ◽  
Author(s):  
Kelly A. Barnett ◽  
A. Stanley Culpepper ◽  
Alan C. York ◽  
Lawrence E. Steckel
Keyword(s):  
United States ◽  
Weed Control ◽  
Acetolactate Synthase ◽  
The United States ◽  
Palmer Amaranth ◽  
Effective Control ◽  
Yield Response ◽  
Amaranthus Palmeri ◽  
Cotton Yield ◽  
Cotton Cultivar

Glyphosate-resistant (GR) weeds, especially GR Palmer amaranth, are very problematic for cotton growers in the Southeast and Midsouth regions of the United States. Glufosinate can control GR Palmer amaranth, and growers are transitioning to glufosinate-based systems. Palmer amaranth must be small for consistently effective control by glufosinate. Because this weed grows rapidly, growers are not always timely with applications. With widespread resistance to acetolactate synthase-inhibiting herbicides, growers have few herbicide options to mix with glufosinate to improve control of larger weeds. In a field study using a WideStrike®cotton cultivar, we evaluated fluometuron at 140 to 1,120 g ai ha−1mixed with the ammonium salt of glufosinate at 485 g ae ha−1for control of GR Palmer amaranth 13 and 26 cm tall. Standard PRE- and POST-directed herbicides were included in the systems. Glufosinate alone injured the WideStrike® cotton less than 10%. Fluometuron increased injury up to 25% but did not adversely affect yield. Glufosinate controlled 13-cm Palmer amaranth at least 90%, and there was no improvement in weed control nor a cotton yield response to fluometuron mixed with glufosinate. Palmer amaranth 26 cm tall was controlled only 59% by glufosinate. Fluometuron mixed with glufosinate increased control of the larger weeds up to 28% and there was a trend for greater yields. However, delaying applications until weeds were 26 cm reduced yield 22% relative to timely application. Our results suggest fluometuron mixed with glufosinate may be of some benefit when attempting to control large Palmer amaranth. However, mixing fluometuron with glufosinate is not a substitute for a timely glufosinate application.

The Critical Period of Weed Control in Grain Corn (Zea mays)

Weed Science ◽  
1992 ◽  
Vol 40 (3) ◽  
pp. 441-447 ◽  
Author(s):  
Michael R. Hall ◽  
Clarence J. Swanton ◽  
Glenn W. Anderson
Keyword(s):  
Zea Mays ◽  
Leaf Area ◽  
Weed Control ◽  
Critical Period ◽  
Field Studies ◽  
Southern Ontario ◽  
Leaf Stage ◽  
Individual Leaf ◽  
Logistic Equations ◽  
Weed Interference

Field studies were conducted in southern Ontario to determine the critical period of weed control in grain corn and the influence of weed interference on corn leaf area. The Gompertz and logistic equations were fitted to data representing increasing durations of weed control and weed interference, respectively. The beginning of the critical period varied from the 3- to 14-leaf stages of corn development However, the end of the critical period was less variable and ended on average at the 14-leaf stage. Weed interference reduced corn leaf area by reducing the expanded leaf area of each individual leaf and accelerating senescence of lower leaves. In addition, weed interference up to the 14-leaf stage of corn development impeded leaf expansion and emergence in 1989.

Stale seedbed weed control in cucumber

Weed Science ◽  
1998 ◽  
Vol 46 (6) ◽  
pp. 698-702 ◽  
Author(s):  
W. Carroll Johnson ◽  
Benjamin G. Mullinix
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Management System ◽  
Field Studies ◽  
Management Systems ◽  
Yellow Nutsedge ◽  
Predominant Species ◽  
Combination System ◽  
Cucumber Yield

Field studies were conducted from 1995 to 1997 near Tifton, GA, to determine the benefits of stale seedbed weed control in cucumber. Three stale seedbed management systems—(1) power till stale seedbeds twice (2 ×), (2) glyphosate application immediately after planting, and (3) combination system of stale seedbeds power tilled once 2 wk prior to planting followed by glyphosate application immediately after planting cucumber—were evaluated as main plots. Subplots were weed management systems after planting cucumber: intensive, basic, and cultivation alone. Weed densities were generally greater in 1996 and 1997 than in 1995. Yellow nutsedge was the overall predominant species in 1995 (46 plants m−2), with Florida pusley being the predominant species in 1996 and 1997, at 80 and 124 plants m−2, respectively. Generally, stale seedbeds shallow tilled 2 × had fewer weeds and greater cucumber yields than stale seedbeds treated with glyphosate. Glyphosate did not adequately control emerged Florida pusley on stale seedbeds, resulting in reduced cucumber yield. Clomazone preemergence and bentazon/halosulfuron postemergence were used for broadleaf weed control in the intensive weed management system. These herbicides injured cucumber plants, delayed maturity, and reduced yield. Based on our results, stale seedbeds shallow tilled 2 × can be integrated into cucumber production and provide effective cultural weed control. Furthermore, these systems will replace the need for potentially injurious herbicides.

Integration of a Brassicaceae Cover Crop with Herbicides in Plasticulture Tomato

2009 ◽  
Vol 23 (2) ◽  
pp. 280-286 ◽  
Author(s):  
Sanjeev K. Bangarwa ◽  
Jason K. Norsworthy ◽  
Edward E. Gbur
Keyword(s):  
Weed Control ◽  
Cover Crop ◽  
Fruit Yield ◽  
Palmer Amaranth ◽  
Marketable Yield ◽  
Purple Nutsedge ◽  
Yellow Nutsedge ◽  
Full Rate ◽  
Over The Top ◽  
Large Crabgrass

Weeds are a major constraint in tomato production, especially in the absence of methyl bromide. Field trials were conducted in 2006 and 2007 to evaluate the integrated use of a mustard ‘Caliente’ (a blend of brown and white mustard) cover crop with one-half and full rate PRE/POST herbicides for weed control and crop response in polyethylene-mulched tomato. Caliente was flail mowed and incorporated into the soil prior to forming beds. PRE herbicides were applied under polyethylene mulch, and POST herbicides were sprayed over the top of tomato. Full rates for S-metolachlor, halosulfuron, and trifloxysulfuron were 1,600, 27, and 7.9 g ai/ha, respectively. Caliente had no effect on weed control or tomato injury and yield. Except for large crabgrass control and tomato injury and yield, only the main effect of herbicide selection and application rate affected these parameters. Tomato injury was minimal (< 6%) from PRE- and POST-applied herbicides. S-metolachlor applied PRE provided 66% purple nutsedge, 67% yellow nutsedge, and 77% Palmer amaranth control at 4 wk after transplanting (WATP). S-metolachlor–treated plots at the full rate produced the highest marketable fruit yield among herbicide treatments, with jumbo fruit yield equivalent to the hand-weeded treatment. Trifloxysulfuron was the best POST-applied herbicide based on marketable yield and weed control. POST-applied trifloxysulfuron provided 41% purple nutsedge, 58% yellow nutsedge, and 55% Palmer amaranth control at 8 to 9 WATP. Halosulfuron applied PRE controlled purple and yellow nutsedge 70 and 78%, respectively, at 4 WATP, and POST-applied halosulfuron controlled purple nutsedge 74% and yellow nutsedge 78% at 8 to 9 WATP. Halosulfuron applied either PRE or POST failed to control Palmer amaranth and large crabgrass. Greater weed control and marketable tomato yield were achieved with full rates of herbicides. This research demonstrates no additional advantage of Caliente mustard when used with herbicides in tomato. None of the PRE or POST herbicides applied alone were sufficient to maintain season-long, broad-spectrum weed control and optimum marketable yield in tomato. Therefore, integration of PRE and POST herbicides at full rates is suggested.

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