Weed Management Systems in Glyphosate-Resistant Cotton

2005 ◽  
Vol 19 (2) ◽  
pp. 422-429 ◽  
Author(s):  
Ian C. Burke ◽  
Shawn C. Troxler ◽  
Shawn D. Askew ◽  
John W. Wilcut ◽  
W. David Smith

Studies were conducted at Clayton, Lewiston-Woodville, and Rocky Mount, NC, to evaluate weed and cotton response to herbicide systems in glyphosate-resistant cotton in 1995 and 1997. Herbicide systems evaluated included various combinations of soil-applied (trifluralin and fluometuron) and postemergence (POST) (glyphosate or pyrithiobac) herbicides with or without late postemergence-directed (LAYBY) treatments of cyanazine plus MSMA. Glyphosate-resistant cotton injury was less than 5% with all herbicide treatments. Glyphosate POST systems were as efficacious in weed control as other herbicide systems. Depending on location, glyphosate and pyrithiobac POST systems usually required cyanazine plus MSMA LAYBY for season-long control of common lambsquarters, goosegrass, large crabgrass, pitted morningglory, prickly sida, and Texas panicum. Glyphosate POST applied as needed provided weed control equivalent to soil-applied plus POST herbicides, although lint yield was slightly reduced depending on location. Herbicide systems that included soil-applied herbicides required one to two treatments of glyphosate POST and post-directed for season-long weed control and high cotton lint yields, whereas the same herbicide systems without soil-applied herbicides required two to three glyphosate treatments. In all herbicide systems, a residual soil-applied or LAYBY herbicide treatment increased yield compared with glyphosate POST only systems. Location influenced weed control and cotton yield. Generally, as herbicide inputs increased, yield increased.

2004 ◽  
Vol 18 (2) ◽  
pp. 268-276 ◽  
Author(s):  
Ian C. Burke ◽  
John W. Wilcut

An experiment was conducted at five locations in North Carolina during 2000 and 2001 to evaluate weed control, crop injury, and cotton yield. Weed management systems included different combinations of pyrithiobac preemergence (PRE), fluometuron PRE, CGA-362622 postemergence (POST), pyrithiobac POST, and monosodium salt of methylarsonic acid (MSMA) plus prometryn applied late POST-directed (LAYBY). At Goldsboro in 2000, cotton was injured 74 to 78% by CGA-362622 POST when evaluated 4 to 7 d after treatment (DAT). Injury at Clayton, Goldsboro, and Lewiston in 2001 and Rocky Mount in 2000 was less than 16% 4 to 7 DAT with the same treatment and was not apparent by 62 DAT. CGA-362622 controlled common lambsquarters, common ragweed, Palmer amaranth, sicklepod, smooth pigweed, andIpomoeaspecies including entireleaf, ivyleaf, and pitted morningglory, and the addition of pyrithiobac to the herbicide system, either PRE or POST, increased control ofAmaranthusspecies, jimsonweed, and prickly sida. CGA-362622 did not control jimsonweed or prickly sida. Fluometuron PRE, pyrithiobac PRE, and MSMA plus prometryn LAYBY were beneficial for increasing weed control and cotton lint yields. Prometryn plus MSMA LAYBY increased control of common ragweed, entireleaf morningglory, jimsonweed, pitted morningglory, and smooth pigweed and provided higher cotton yields than similar systems without a LAYBY. The greatest weed control and greatest cotton lint yields required complete weed management systems that included a combination of PRE, POST, and LAYBY treatments.


2006 ◽  
Vol 20 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Walter E. Thomas ◽  
Tim T. Britton ◽  
Scott B. Clewis ◽  
Shawn D. Askew ◽  
John W. Wilcut

Field studies were conducted at three locations to evaluate glyphosate-resistant (GR) cotton response, weed control, and cotton lint yields to two formulations of glyphosate (diammonium salt– glyphosate and isopropylamine salt–glyphosate) and trifloxysulfuron applied early postemergence (EPOST) alone or to tank mixtures of trifloxysulfuron with each glyphosate formulation, with and without a late postemergence-directed (LAYBY) treatment of prometryn plus MSMA. Trifloxysulfuron and both formulations of glyphosate controlled common lambsquarters and pitted morningglory. Both glyphosate formulations provided equivalent control of common lambsquarters, goosegrass, pitted morningglory, prickly sida, and smooth pigweed. Trifloxysulfuron controlled smooth pigweed better than either glyphosate formulation but did not control goosegrass or prickly sida. Prometryn plus MSMA LAYBY improved late-season control of common lambsquarters, goosegrass, large crabgrass, and pitted morningglory for all EPOST systems and improved late-season smooth pigweed control for EPOST systems that did not include trifloxysulfuron. Cotton injury was 2% or less from both glyphosate formulations, while trifloxysulfuron injured ‘Deltapine 5415RR’ 7 to 16% at two locations. At a third location, trifloxysulfuron injured ‘Paymaster 1218RR/BG’ 24%, and when applied in mixture with either glyphosate formulation, injury increased to at least 72%. Cotton injury was transient at the first two locations and was not visually apparent 3 to 5 wk later. Cotton yield at the third location was reduced. High cotton yields reflected high levels of weed control.


1999 ◽  
Vol 13 (2) ◽  
pp. 324-333 ◽  
Author(s):  
A. Stanley Culpepper ◽  
Alan C. York

An experiment was conducted at five locations in North Carolina to compare management systems utilizing glufosinate applied postemergence (POST) in glufosinate-resistant corn with standard systems of metolachlor plus atrazine preemergence (PRE) or nicosulfuron plus atrazine POST Glufosinate alone and both standard systems controlled common ragweed and prickly sida at least 98%, whereas sicklepod control was < 20% late in the season. Late-season control of common lambsquarters, smooth pigweed, pitted morningglory, and tall morningglory was generally less with glufosinate alone than with the standard systems. However, late-season control of common lambsquarters, smooth pigweed, pitted morningglory, tall morningglory, and sicklepod by mixtures of glufosinate plus atrazine was at least 99, 100, 89, 93, and 81%, respectively, and was equal to or greater than control by either standard. Broadleaf signalgrass, large crabgrass, and fall panicum were controlled similarly by glufosinate and the standards. Goosegrass control by glufosinate was similar to control by nicosulfuron plus atrazine, but it was less than control by metolachlor plus atrazine. Metolachlor applied PRE or atrazine mixed with glufosinate increased goosegrass control to that achieved with metolachlor plus atrazine. Mixing atrazine with glufosinate did not affect fall panicum control, but metolachlor PRE followed by glufosinate controlled fall panicum as well as the standards. Cultivation or ametryn applied at layby increased control when PRE or POST herbicides alone controlled weeds less than about 90%. Ametryn was generally more effective than cultivation. Glufosinate POST followed by ametryn at layby controlled sicklepod > 90% and other species > 95% late in the season. Corn yield and net returns were similar in the glufosinate and standard systems.


2009 ◽  
Vol 23 (3) ◽  
pp. 391-397 ◽  
Author(s):  
Wesley J. Everman ◽  
Scott B. Clewis ◽  
Alan C. York ◽  
John W. Wilcut

Field studies were conducted near Clayton, Lewiston, and Rocky Mount, NC in 2005 to evaluate weed control and cotton response to preemergence treatments of pendimethalin alone or in a tank mixture with fomesafen, postemergence treatments of glufosinate applied alone or in a tank mixture withS-metolachlor, and POST-directed treatments of glufosinate in a tank mixture with flumioxazin or prometryn. Excellent weed control (> 91%) was observed where at least two applications were made in addition to glufosinate early postemergence (EPOST). A reduction in control of common lambsquarters (8%), goosegrass (20%), large crabgrass (18%), Palmer amaranth (13%), and pitted morningglory (9%) was observed when residual herbicides were not included in PRE or mid-POST programs. No differences in weed control or cotton lint yield were observed between POST-directed applications of glufosinate with flumioxazin compared to prometryn. Weed control programs containing three or more herbicide applications resulted in similar cotton lint yields at Clayton and Lewiston, and Rocky Mount showed the greatest variability with up to 590 kg/ha greater lint yield where fomesafen was included PRE compared to pendimethalin applied alone. Similarly, an increase in cotton lint yields of up to 200 kg/ha was observed whereS-metolachlor was included mid-POST when compared to glufosinate applied alone, showing the importance of residual herbicides to help maintain optimal yields. Including additional modes of action with residual activity preemergence and postemergence provides a longer period of weed control, which helps maintain cotton lint yields.


2005 ◽  
Vol 19 (3) ◽  
pp. 753-761 ◽  
Author(s):  
Mary D. Paulsgrove ◽  
Whitnee L. Barker ◽  
John W. Wilcut

An experiment was conducted at four locations in North Carolina in 1996 and 1997 to evaluate weed control and cotton response in conventional-tillage bromoxynil-resistant cotton. Weed management systems evaluated included a factorial arrangement of bromoxynil postemergence (POST) at 0, 0.28, 0.42, or 0.56 kg ai/ha in mixture with pyrithiobac POST at 0, 0.018, 0.032, or 0.072 kg ai/ha. Additional treatments evaluated included trifluralin preplant-incorporated (PPI) plus fluometuron preemergence (PRE). All systems received a postemergence-directed (PDS) treatment of fluometuron plus MSMA. Bromoxynil at 0.42 kg/ha POST followed by (fb) fluometuron plus MSMA PDS controlled common lambsquarters, common ragweed, eclipta, prickly sida, redroot pigweed, spurred anoda; and entireleaf, ivyleaf, pitted, and tall morningglory at least 93%, whereas smooth pigweed and volunteer peanut were controlled 73 and 86%, respectively. Pyrithiobac at 0.036 kg/ha POST fb fluometuron plus MSMA PDS controlled eclipta, common ragweed, prickly sida, redroot, and smooth pigweed, and spurred anoda at least 94%. Volunteer peanut was controlled 84% by pyrithiobac at 0.032 kg/ha, whereas pitted, ivyleaf, and entireleaf morningglory were controlled by 63, 78, and 83%, respectively. Pyrithiobac at 0.072 kg/ha fb fluometuron plus MSMA PDS controlled common lambsquarters 48%. Cotton yield with bromoxynil plus pyrithiobac POST mixtures were equivalent to trifluralin PPI plus fluometuron PRE at three locations and better at the fourth location. Bromoxynil-resistant cotton ‘47’ and ‘57’ had excellent tolerance to all POST herbicide treatments.


1997 ◽  
Vol 11 (2) ◽  
pp. 335-345 ◽  
Author(s):  
A. Stanley Culpepper ◽  
Alan C. York

An experiment was conducted at four locations in North Carolina during 1994 and 1995 to evaluate weed control, cotton yield, fiber quality, and net returns in no-tillage bromoxynil-tolerant cotton. The experiment focused on using bromoxynil or pyrithiobac sodium applied early POST over-the-top as alternatives to fluometuron plus MSMA applied early POST directed. Fluometuron plus MSMA was more effective than bromoxynil or pyrithiobac sodium on tall morningglory, large crabgrass, goosegrass, and broadleaf signalgrass. Bromoxynil and fluometuron plus MSMA were similarly effective on common lambsquarters, common ragweed, and eclipta and more effective than pyrithiobac sodium. Pyrithiobac sodium and fluometuron plus MSMA were similarly effective on smooth pigweed and Palmer amaranth and more effective than bromoxynil. Prickly sida control by bromoxynil and pyrithiobac sodium was equal to or greater than control by fluometuron plus MSMA. All early POST herbicides controlled pitted morningglory similarly. Regardless of the early POST herbicides used, fluometuron applied PRE and cyanazine plus MSMA applied late POST directed increased control of most weeds and increased cotton yield and net returns. Bromoxynil and pyrithiobac sodium effectively substituted for fluometuron plus MSMA only in systems that included fluometuron applied PRE and cyanazine plus MSMA applied late POST directed. Effects of herbicide systems on cotton fiber quality were minor.


1999 ◽  
Vol 13 (2) ◽  
pp. 276-282 ◽  
Author(s):  
Shawn D. Askew ◽  
John W. Wilcut ◽  
Vernon B. Langston

Cloransulam-methyl applied postemergence (POST) following various preplant-incorporated (PPI) herbicides was evaluated in four experiments for weed control in North Carolina soybean over a 2-yr period at three locations. Acifluorfen plus bentazon or chlorimuron alone applied POST injured soybean more than cloransulam-methyl when following any soil-applied herbicide. When following trifluralin PPI, cloransulam-methyl controlled common ragweed, entireleaf morningglory, and pitted morningglory comparable to acifluorfen plus bentazon or chlorimuron. Common lambsquarters and prickly sida control was higher when acifluorfen plus bentazon was applied POST following trifluralin PPI compared to trifluralin PPI followed by cloransulam-methyl or chlorimuron. Acifluorfen plus bentazon or chlorimuron POST controlled yellow nutsedge and smooth pigweed more than cloransulam-methyl POST when following trifluralin PPI. When trifluralin was applied PPI in mixtures with chlorimuron plus metribuzin, flumetsulam, or imazaquin, control of most species was similar regardless of POST treatment used. Soybean treated with cloransulam-methyl yielded 250 kg/ha more than treatments with chlorimuron when these herbicides followed trifluralin plus flumetsulam or trifluralin plus imazaquin. Net returns with different herbicide systems followed trends similar to soybean yield.


Weed Science ◽  
2003 ◽  
Vol 51 (6) ◽  
pp. 1002-1009 ◽  
Author(s):  
Dunk Porterfield ◽  
John W. Wilcut ◽  
Jerry W. Wells ◽  
Scott B. Clewis

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.


2004 ◽  
Vol 18 (2) ◽  
pp. 315-324 ◽  
Author(s):  
Leanna L. Lyon ◽  
J. Wayne Keeling ◽  
Peter A. Dotray

Field experiments were conducted in 1999 and 2000 to evaluate and adapt the Herbicide Application Decision Support System (HADSS®) program for Texas Southern High Plains cotton production. Weed management systems (in glyphosate-resistant, bromoxynil-resistant, and nontransgenic cotton varieties) included trifluralin preplant incorporated (PPI) followed by (fb) HADSS postemergence-topical (POST) recommendations (PPI fb POST HADSS), HADSS recommendations alone (POST HADSS), and Texas Agricultural Experiment Station (TAES) recommendations for the Texas Southern High Plains. In both years, effective season-long weed control was achieved with all weed management systems in the glyphosate-resistant variety, but only the PPI fb POST HADSS and TAES weed management systems controlled Palmer amaranth and devil's-claw in the bromoxynil-resistant and nontransgenic varieties, compared with POST HADSS alone. No differences in cotton lint yield or net returns over weed control costs were observed with weed management systems across variety in 1999; however, in general, the glyphosate-resistant and nontransgenic varieties produced higher yields and net returns than the bromoxynil-resistant variety. In 2000, plots from the TAES weed management system produced higher lint yields than the plots of PPI fb POST HADSS recommendations in the glyphosate- and bromoxynil-resistant varieties, but plots of all management systems yielded similarly in the nontransgenic variety. In 2000, plots from the TAES system produced the highest net returns in the glyphosate- and bromoxynil-resistant varieties. In the nontransgenic variety, the PPI fb POST HADSS and TAES weed management systems produced higher net returns over weed control costs than the POST HADSS system.


2009 ◽  
Vol 23 (1) ◽  
pp. 6-10 ◽  
Author(s):  
David L. Jordan ◽  
Sarah H. Lancaster ◽  
James E. Lanier ◽  
Bridget R. Lassiter ◽  
P. Dewayne Johnson

Research was conducted in North Carolina to compare weed control by various rates of imazapic POST alone or following diclosulam PRE. In a second experiment, weed control by imazapic applied POST alone or with acifluoren, diclosulam, or 2,4-DB was compared. In a final experiment, yellow nutsedge control by imazapic alone and with the fungicides azoxystrobin, chlorothalonil, pyraclostrobin, and tebuconazole was compared. Large crabgrass was controlled more effectively by imazapic POST than diclosulam PRE. Common lambsquarters, common ragweed, and eclipta were controlled more effectively by diclosulam PRE than imazapic POST. Nodding spurge was controlled similarly by both herbicides. Few differences in control were noted when comparing imazapic rates after diclosulam PRE. Applying either diclosulam PRE or imazapic POST alone or in combination increased peanut yield over nontreated peanut in five of six experiments. Few differences in pod yield were noted when comparing imazapic rates. Acifluorfen, diclosulam, and 2,4-DB did not affect entireleaf morningglory, large crabgrass, nodding spurge, pitted morningglory, and yellow nutsedge control by imazapic. Eclipta control by coapplication of imazapic and diclosulam exceeded control by imazapic alone. The fungicides azoxystrobin, chlorothalonil, pyraclostrobin, and tebuconazole did not affect yellow nutsedge control by imazapic.


Sign in / Sign up

Export Citation Format

Share Document