Economic Assessment of Weed Management in Strip- and Conventional-Tillage Nontransgenic and Transgenic Cotton

2007 ◽  
Vol 21 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Scott B. Clewis ◽  
John W. Wilcut

Studies were conducted to evaluate weed management systems in nontransgenic, bromoxynil-resistant, and glyphosate-resistant cotton in strip- and conventional-tillage environments. Tillage did not affect weed control, cotton lint yields, or net returns. Early season stunting in strip-tillage cotton was 5% or less, regardless of herbicide system or cultivar and was transient. Excellent (> 90%) control of common lambsquarters, common ragweed, andIpomoeaspecies, including entireleaf, ivyleaf, pitted and tall morningglories, jimsonweed, prickly sida, and velvetleaf, was achieved with systems containing bromoxynil, glyphosate, and pyrithiobac early postemergence (EPOST). Glyphosate systems provided better and more consistent control of fall panicum and large crabgrass than bromoxynil and pyrithiobac systems. Bromoxynil and pyrithiobac EPOST did not control sicklepod unless applied in mixture with MSMA and followed by (fb) a late postemergence-directed (LAYBY) treatment of prometryn plus MSMA. Palmer amaranth was controlled (> 90%) with all glyphosate and pyrithiobac systems and with the bromoxynil system that included a broadcast soil-applied herbicide treatment. Bromoxynil systems without a broadcast soil-applied herbicide treatment controlled Palmer amaranth 87% or less. Herbicide systems that included glyphosate EPOST controlled sicklepod with or without a soil-applied herbicide treatment. The highest yielding cotton included all the glyphosate systems and bromoxynil systems that contained a soil-applied herbicide treatment. Nontransgenic systems that included a soil-applied herbicide treatment yielded less than a system with soil-applied treatment plus glyphosate EPOST. Net returns from glyphosate systems were generally higher than net returns from bromoxynil or pyrithiobac systems.

Weed Science ◽  
1999 ◽  
Vol 47 (5) ◽  
pp. 596-601 ◽  
Author(s):  
Mary D. Paulsgrove ◽  
John W. Wilcut

An experiment was conducted at two locations in Georgia and two locations in North Carolina during 1994 and 1995 to evaluate weed management in conventional-tillage bromoxynil-resistantGossypium hirsutumL. (cotton). The weed management systems evaluated included different combinations of fluometuron preemergence (PRE), bromoxynil or bromoxynil plus MSMA early postemergence (EPOST), bromoxynil postemergence (POST), and cyanazine plus MSMA late post-directed (LAYBY). Fluometuron PRE improved control ofAcanthospermum hisptdiumDC. (bristly starbur),Cassia occidentalisL. (coffee senna),Chenopodium albumL. (common lambsquarters),Desmodium tortuosum(Sw.) DC. (Florida beggarweed),Sida spinosaL. (prickly sida),Jacquemontia tamnifolia(L.) Griseb. (smallflower morningglory), andAnoda cristata(L.) Schlecht. (spurred anoda), compared to system that did not use fluometuron PRE. It also improvedG. hirsutumyields at three four locations. Bromoxynil-containing systems provided better weed control and higherG. hirsutumyields than systems without bromoxynil. Bromoxynil EPOST controlledA. hispidium, C. occidentalis, C. album, D. tortuosum, S. spinosa, J. tamnifolia, andA. cristata.Control of these species was frequently improved by a second application of bromoxynil POST. Bromoxynil EPOST, POST, or EPOST plus POST did not controlSenna obtusifolia(L.) Irwin and Barneby (sicklepod), but the addition of MSMA to bromoxynil EPOST improvedS. obtusifoliacontrol. Control of all dicotyledonous weeds was improved by a LAYBY treatment of cyanazine plus MSMA, and yields were improved at three of four locations with this treatment.Gossypium hirsutumwas not injured by POST treatments of bromoxynil, and only temporary injury resulted from POST treatments of MSMA.


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.


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.


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.


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.


1999 ◽  
Vol 13 (2) ◽  
pp. 411-420 ◽  
Author(s):  
A. Stanley Culpepper ◽  
Alan C. York

Weed management systems were compared in bromoxynil-resistant, glyphosate-resistant, and nontransgenic cotton. A standard system of pendimethalin preplant incorporated (PPI), fluometuron preemergence (PRE), fluometuron plus MSMA early postemergence-directed (POST-DIR), and cyanazine plus MSMA late POST-DIR in combination with cultivation controlled broadleaf signalgrass, large crabgrass, common lambsquarters, jimsonweed, pitted morningglory, prickly sida, sicklepod, and smooth pigweed 98 to 100% late season. Weed control, cotton yield, and net returns were similar when pyrithiobac or bromoxynil plus MSMA postemergence (POST) replaced fluometuron plus MSMA POST-DIR. Fluometuron PRE had little to no effect in bromoxynil systems. Glyphosate POST to three- to four-leaf-stage cotton followed by cyanazine plus MSMA late POST-DIR and cultivation controlled weeds 96 to 100%. Glyphosate POST followed by glyphosate POST-DIR and cultivation controlled pitted morningglory and large crabgrass 89 to 90% and other species at least 94%. Yields and net returns at one location were similar for glyphosate applied twice or glyphosate POST followed by cyanazine plus MSMA POST-DIR and the standard system. Pendimethalin plus fluometuron in glyphosate systems did not increase yield or net returns. At a location severely infested with large crabgrass, pendimethalin plus fluometuron in glyphosate systems increased yield 37 to 44% and net returns 85 to 108%, respectively, when glyphosate was applied to cotton at the three-to four-leaf stage, but not if glyphosate was applied to cotton at the one-leaf stage. Yield and net returns were similar when bromoxynil-resistant, glyphosate-resistant, and nontransgenic cotton were treated using the standard system.


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.


1991 ◽  
Vol 5 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Robert H. Walker ◽  
Bobby E. Norris ◽  
John A. McGuire

Field experiments in 1984 and 1985 near Headland, AL involved the influence of 18 integrated weed management systems incorporated from nine herbicide-tillage systems (H-T) and two row patterns on control of large crabgrass and Texas panicum, crop yield, and net returns in grain sorghum. The conventional-tillage system plus herbicide combinations; alachlor preplant incorporated (PPI), atrazine postemergence (POST), and paraquat POST directed, provided 90% or greater control of large crabgrass throughout the season and high sorghum yields in one of two years; and 90% or greater control of Texas panicum from mid-June through mid-August and high sorghum yields in both years. Results in 1984 and 1985 similar to those above were obtained with strip tillage plus herbicide combinations; alachlor PPI, atrazine POST, and paraquat POST directed; alachlor PPI and tridiphane plus atrazine POST; and tridiphane plus atrazine POST and paraquat POST directed. Row patterns did not consistently influence control of large crabgrass, Texas panicum, or sorghum yield. Economic net returns ranged from – $20 to $210 per hectare for the large crabgrass control systems in 1984; however, low sorghum yields in 1985 resulted largely in negative returns. Similar net returns were obtained in the Texas panicum experiment.


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.


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