Influence of Spray-Solution Temperature and Holding Duration on Weed Control with Premixed Glyphosate and Dicamba Formulation

2016 ◽  
Vol 30 (1) ◽  
pp. 116-122 ◽  
Author(s):  
Pratap Devkota ◽  
Fred Whitford ◽  
William G. Johnson
Keyword(s):  
Weed Control ◽  
Palmer Amaranth ◽  
High Rate ◽  
Solution Temperature ◽  
Weed Species ◽  
Related Factors ◽  
Spray Solution ◽  
Giant Ragweed ◽  
Pitted Morningglory ◽  
Low Rate

Water is the primary carrier for herbicide application, and carrier-water–related factors can influence herbicide performance. In a greenhouse study, premixed formulation of glyphosate plus dicamba was mixed in deionized (DI) water at 5, 18, 31, 44, or 57 C and applied immediately. In a companion study, glyphosate and dicamba formulation was mixed in DI water at temperatures of 5, 22, 39, or 56 C and sprayed after the herbicide solution was left at the respective temperatures for 0, 6, or 24 h. In both studies, glyphosate plus dicamba was applied at 0.275 plus 0.137 kg ae ha−1(low rate), and 0.55 plus 0.275 kg ha−1(high rate), respectively, to giant ragweed, horseweed, Palmer amaranth, and pitted morningglory. Glyphosate plus dicamba applied at a low rate with solution temperature of 31 C provided 14% and 26% greater control of giant ragweed and pitted morningglory, respectively, compared to application at solution temperature of 5 C. At both rates of glyphosate and dicamba formulation, giant ragweed and pitted morningglory control was 15% or greater at solution temperature of 44 C compared to 5 C. Weed control was not affected with premixture of glyphosate and dicamba applied ≤ 24 h after mixing herbicide. When considering solution temperature, glyphosate and dicamba applied at low rate provided 13 and 6% greater control of Palmer amaranth and pitted morningglory, respectively, with solution temperature of 22 C compared to 5 C. Similarly, giant ragweed control was 8% greater with solution temperature of 39 C compared to 5 C. Glyphosate and dicamba applied at high rate provided 8% greater control of giant ragweed at solution temperature of 22 or 39 C compared to 5 C. Therefore, activity of premixed glyphosate and dicamba could be reduced with spray solution at lower temperature; however, the result is dependent on weed species.

Efficacy of dicamba and glyphosate as influenced by carrier water pH and hardness

2019 ◽  
Vol 34 (1) ◽  
pp. 101-106
Author(s):  
Pratap Devkota ◽  
William G. Johnson
Keyword(s):  
Field Study ◽  
Water Hardness ◽  
Palmer Amaranth ◽  
Common Ragweed ◽  
Common Lambsquarters ◽  
Greenhouse Study ◽  
Spray Solution ◽  
Giant Ragweed ◽  
Pitted Morningglory ◽  
Water Ph

AbstractHerbicide carrier water hardness and pH can be variable depending on the source and geographic location. Herbicide efficacy can be affected by the pH and hardness of water used for spray solution. Field and greenhouse studies were conducted to evaluate the effect of carrier water pH and hardness on premixed dicamba and glyphosate efficacy. Treatments were combinations of water pH at 4, 6.5, or 9; and water hardness at 0 (deionized water), 400, or 800 mg L−1 of CaCO3 equivalent. In the field study, dicamba and glyphosate were applied at 0.55 and 1.11 kg ae ha−1, respectively, and half of these rates were applied in the greenhouse study. There was no interaction between carrier water pH and hardness on dicamba and glyphosate efficacy; however, the main effects of carrier water pH and hardness were significant. Herbicide efficacy was reduced with carrier water at pH 9 compared with pH 4. In the field study, common lambsquarters, common ragweed, horseweed, or Palmer amaranth control was improved 6% or more at carrier water at pH 4 compared with pH 9. Similar results were observed with water pH for giant ragweed, Palmer amaranth, or pitted morningglory control in the greenhouse study. Carrier water hardness at 400 or 800 mg L−1 reduced common ragweed, giant ragweed, or horseweed control compared with 0 mg L−1. Similarly, common lambsquarters, Palmer amaranth, or pitted morningglory control was reduced at least 10% with carrier water hardness at 800 mg L−1 compared with 0 mg L−1. These results indicate carrier water at acidic pH and of no hardness is critical for dicamba and glyphosate application, and spray solution needs to be amended appropriately for an optimum efficacy.

Influence of carrier water pH, foliar fertilizer, and ammonium sulfate on 2,4-D and 2,4-D plus glyphosate efficacy

2019 ◽  
Vol 33 (04) ◽  
pp. 562-568 ◽  
Author(s):  
Pratap Devkota ◽  
William G. Johnson
Keyword(s):  
Field Study ◽  
Ammonium Sulfate ◽  
Weed Control ◽  
Palmer Amaranth ◽  
Weed Species ◽  
Foliar Fertilizer ◽  
Greenhouse Study ◽  
Giant Ragweed ◽  
Negative Effect ◽  
Water Ph

AbstractCarrier water pH is an important factor for enhancing herbicide efficacy. Coapplying agrochemical products with the herbicide might save time and resources; however, the negative effect of foliar fertilizers on herbicide efficacy should be thoroughly evaluated. In greenhouse studies, the effect of carrier water pH (4, 6.5, and 9), foliar fertilizer (zinc [Zn], manganese [Mn], or without fertilizer), and ammonium sulfate (AMS) at 0% or 2.5% vol/vol was evaluated on 2,4-D and premixed 2,4-D plus glyphosate efficacy for giant ragweed, horseweed, and Palmer amaranth control. In addition, a field study was conducted to evaluate the effect of carrier water pH (4, 6.5, and 9); and Zn or Mn foliar fertilizer on premixed 2,4-D plus glyphosate efficacy for horseweed and Palmer amaranth control. In the greenhouse study, 2,4-D and premixed 2,4-D plus glyphosate provided 5% greater weed control at acidic compared with alkaline carrier water pH. Coapplied Mn foliar fertilizer reduced 2,4-D and premixed 2,4-D plus glyphosate efficacy at least 5% for weed control. Addition of AMS enhanced 2,4-D and premixed 2,4-D plus glyphosate efficacy at least 6% for giant ragweed, horseweed, and Palmer amaranth control. In the field study, few significant differences occurred between coapplied Zn or Mn foliar fertilizer for any treatment variables. Therefore, carrier water pH, coapplied foliar fertilizer, and water-conditioning adjuvants have potential to influence herbicide performance. However, weed species could play a role in the differential response of these factors on herbicide efficacy.

Effect of Carrier Water Hardness and Ammonium Sulfate on Efficacy of 2,4-D Choline and Premixed 2,4-D Choline Plus Glyphosate

2016 ◽  
Vol 30 (4) ◽  
pp. 878-887 ◽  
Author(s):  
Pratap Devkota ◽  
William G. Johnson
Keyword(s):  
Water Quality ◽  
Ammonium Sulfate ◽  
Linear Trend ◽  
Water Hardness ◽  
Hard Water ◽  
Palmer Amaranth ◽  
Weed Species ◽  
Hardness Level ◽  
Spray Solution ◽  
Giant Ragweed

Spray water quality is an important consideration for optimizing herbicide efficacy. Hard water cations in the carrier water can reduce herbicide performance. Greenhouse studies were conducted to evaluate the influence of hard water cations and the use of ammonium sulfate (AMS) on the efficacy of 2,4-D choline and premixed 2,4-D choline plus glyphosate for giant ragweed, horseweed, and Palmer amaranth control. Carrier water hardness was established at 0, 200, 400, 600, 800, or 1,000 mg L−1using CaCl2and MgSO4, and each hardness level consisted of without or with AMS at 10.2 g L−1. One-third of the proposed use rates of 2,4-D choline at 280 g ae ha−1and 2,4-D choline plus glyphosate at 266 plus 283 g ae ha−1, respectively, were applied in the study. An increase in carrier water hardness showed a linear trend for reducing 2,4-D choline and 2,4-D choline plus glyphosate efficacy on all weed species evaluated in both studies. The increase in water hardness level reduced giant ragweed control with 2,4-D choline and the premix formulation of 2,4-D choline plus glyphosate to a greater extent without AMS than it did with AMS in the spray solution. Increases in water hardness from 0 to 1,000 mg L−1reduced weed control 20% or greater with 2,4-D choline. Likewise, the efficacy of the premixed 2,4-D choline plus glyphosate was reduced 21% or greater with increased water hardness from 0 to 1,000 mg L−1. The addition of AMS improved giant ragweed, horseweed, and Palmer amaranth control ≥ 17% and ≥ 10% for 2,4-D choline and 2,4-D choline plus glyphosate application, respectively. The biomass of all weed species was reduced by ≥ 8% and ≥ 5% with 2,4-D choline and 2,4-D choline plus glyphosate application, respectively, when AMS was added to hard water.

MSMA Antagonizes Glyphosate and Glufosinate Efficacy on Broadleaf and Grass Weeds

2007 ◽  
Vol 21 (1) ◽  
pp. 159-165 ◽  
Author(s):  
Clifford H. Koger ◽  
Ian C. Burke ◽  
Donnie K. Miller ◽  
J. Andrew Kendig ◽  
Krishna N. Reddy ◽  
...  
Keyword(s):  
Weed Control ◽  
Palmer Amaranth ◽  
Weed Species ◽  
Redroot Pigweed ◽  
Pitted Morningglory ◽  
Hemp Sesbania ◽  
Prickly Sida ◽  
Grass Weed ◽  
Better Than ◽  
Levels Of Control

Field and greenhouse studies were conducted to investigate the compatibility of MSMA in a tank mixture with glyphosate or glufosinate for broadleaf and grass weed control. Glyphosate, glufosinate, and MSMA were evaluated at 0.5×, 1×, and 2× rates, with 1× rates of 0.84 kgae/ha, 0.5 kgai/ha, and 2.2 kgai/ha, respectively. Glyphosate and glufosinate provided similar levels of control for most weed species and were often more efficacious than MSMA alone. Glyphosate controlled Palmer amaranth better than glufosinate. Glufosinate controlled hemp sesbania, pitted morningglory, and ivyleaf morningglory better than glyphosate at one location. Weed control was not improved with the addition of MSMA to glyphosate or glufosinate when compared with either herbicide alone. MSMA antagonized glyphosate efficacy on barnyardgrass, browntop millet, hemp sesbania, Palmer amaranth, and redroot pigweed. MSMA antagonized glufosinate efficacy on browntop millet, hemp sesbania, ivyleaf morningglory, johnsongrass, Palmer amaranth, pitted morningglory, prickly sida, redroot pigweed, and velvetleaf. Antagonism of glyphosate or glufosinate by MSMA was often overcome by applying the 2× rate of either herbicide alone. MSMA is not a compatible tank-mixture partner with glyphosate or glufosinate for weed control in cotton.

Herbicide Programs for Enhanced Glyphosate-Resistant and Glufosinate-Resistant Cotton (Gossypium hirsutum)

2011 ◽  
Vol 25 (4) ◽  
pp. 526-534 ◽  
Author(s):  
Dilpreet S. Riar ◽  
Jason K. Norsworthy ◽  
Griff M. Griffith
Keyword(s):  
Weed Control ◽  
Experimental Research ◽  
Palmer Amaranth ◽  
Cotton Yield ◽  
Seed Cotton ◽  
Weed Species ◽  
Late Season ◽  
Pitted Morningglory ◽  
Herbicide Programs ◽  
Cotton Cultivar

Research was conducted at experimental research stations near Keiser and Marianna (Marianna-A), AR, in 2007, and in a grower's field near Marianna (Marianna-B), AR, in 2008, to compare herbicide programs, including POST application(s) of glyphosate/glufosinate alone or in combination with residual herbicides applied as PRE, mid-POST (MPOST), or layby POST-directed (PD) in enhanced glyphosate- and glufosinate-resistant cotton. Weed species evaluated included Palmer amaranth, pitted morningglory, hemp sesbania, barnyardgrass, and a mixture of large crabgrass and goosegrass. At Marianna-B, AR, the Palmer amaranth population was a mixture of glyphosate-resistant and -susceptible plants. For both cotton cultivars and at all locations, inclusion ofS-metolachlor plus fluometuron PRE increased weed control and/or decreased the number of glufosinate or glyphosate applications needed in-season. At Marianna-B, AR, PRE residual herbicides and/or glufosinate were required to control glyphosate-resistant Palmer amaranth. Addition of pyrithiobac to glufosinate or glyphosate did not increase weed control. A layby PD application of flumioxazin plus MSMA was required to increase late-season control of all weed species in POST glufosinate-only programs, but not in POST glyphosate-only programs. None of the programs caused > 5% injury to either cotton cultivar. Seed-cotton yield was similar in all herbicide programs at Keiser, AR, and Marianna-A, AR, except for the POST glyphosate-only program, which yielded less than the PRE followed by POST programs in glyphosate-resistant cotton at Keiser, AR. In general, PRE herbicides did not increase cotton yield but did improve early and late-season control of glyphosate-susceptible and -resistant weeds in both cotton cultivars.

Weed Management with Glyphosate- and Glufosinate-Based Systems in PHY 485 WRF Cotton

2011 ◽  
Vol 25 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Jared R. Whitaker ◽  
Alan C. York ◽  
David L. Jordan ◽  
A. Stanley Culpepper
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Fiber Quality ◽  
Palmer Amaranth ◽  
Weed Species ◽  
Crop Tolerance ◽  
The North ◽  
Annual Grasses ◽  
Resistance Trait ◽  
Cotton Belt

Glyphosate-resistant (GR) Palmer amaranth has become a serious pest in parts of the Cotton Belt. Some GR cotton cultivars also contain the WideStrike™ insect resistance trait, which confers tolerance to glufosinate. Use of glufosinate-based management systems in such cultivars could be an option for managing GR Palmer amaranth. The objective of this study was to evaluate crop tolerance and weed control with glyphosate-based and glufosinate-based systems in PHY 485 WRF cotton. The North Carolina field experiment compared glyphosate and glufosinate alone and in mixtures applied twice before four- to six-leaf cotton. Additional treatments included glyphosate and glufosinate mixed withS-metolachlor or pyrithiobac applied to one- to two-leaf cotton followed by glyphosate or glufosinate alone on four- to six-leaf cotton. All treatments received a residual lay-by application. Excellent weed control was observed from all treatments on most weed species. Glyphosate was more effective than glufosinate on glyphosate-susceptible (GS) Palmer amaranth and annual grasses, while glufosinate was more effective on GR Palmer amaranth. Annual grass and GS Palmer amaranth control by glyphosate plus glufosinate was often less than control by glyphosate alone but similar to or greater than control by glufosinate alone, while mixtures were more effective than either herbicide alone on GR Palmer amaranth. Glufosinate caused minor and transient injury to the crop, but no differences in cotton yield or fiber quality were noted. This research demonstrates glufosinate can be applied early in the season to PHY 485 WRF cotton without concern for significant adverse effects on the crop. Although glufosinate is often less effective than glyphosate on GS Palmer amaranth, GR Palmer amaranth can be controlled with well-timed applications of glufosinate. Use of glufosinate in cultivars with the WideStrike trait could fill a significant void in current weed management programs for GR Palmer amaranth in cotton.

scholarly journals Season-long weed control with sequential herbicide programs in California tree nut crops

2020 ◽  
Vol 34 (6) ◽  
pp. 834-842
Author(s):  
Caio A. C. G. Brunharo ◽  
Seth Watkins ◽  
Bradley D. Hanson
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Control Program ◽  
Early Spring ◽  
High Rate ◽  
Weed Species ◽  
Tree Nut ◽  
Herbicide Use ◽  
Herbicide Programs ◽  
Grass Weed

AbstractWeed control in tree nut orchards is a year-round challenge for growers that is particularly intense during winter through summer as a result of competition and interference with management and harvest operations. A common weed control program consists of an application of a winter PRE and POST herbicide mixture, followed by a desiccation treatment in early spring and before harvest. Because most spring and summer treatments depend on a limited number of foliar-applied herbicides, summer-germinating species and/or herbicide-resistant biotypes become troublesome. Previous research has established effective PRE herbicide programs targeting winter glyphosate-resistant weeds. However, more recently, growers have reported difficulties in controlling several summer-germinating grass weeds with documented or suspected resistance to the spring and summer POST herbicide programs. In this context, research was conducted to evaluate a sequential PRE approach to control winter- and summer-germinating orchard weeds. Eight field experiments were conducted in tree nut orchards to evaluate the efficacy of common winter herbicide programs and a sequential herbicide program for control of a key summer grass weed species. In the sequential-application strategy, three foundational herbicide programs applied in the winter were either mixed with pendimethalin, followed with pendimethalin in March, or applied as a split application of pendimethalin in both winter and spring. Results indicate that the addition of pendimethalin enhanced summer grass weed control throughout the crop growing season by up to 31%. Applying all or part of the pendimethalin in the spring improved control of the summer grass weed junglerice by up to 49%. The lower rate of pendimethalin applied in the spring performed as well as the high rate in the winter, suggesting opportunities for reducing herbicide inputs. Tailoring sequential herbicide programs to address specific weed challenges can be a viable strategy for improving orchard weed control without increasing herbicide use in some situations.

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.

Tolerance of Cantaloupe to Postemergence Applications of Rimsulfuron and Halosulfuron

2007 ◽  
Vol 21 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Charles W. Meister
Keyword(s):  
Field Trials ◽  
Palmer Amaranth ◽  
Weed Species ◽  
Purple Nutsedge ◽  
Leaf Stage ◽  
Early Crop ◽  
Pitted Morningglory ◽  
Plant Injury ◽  
Large Crabgrass

Field trials were conducted in the spring of 2004 and the spring and summer of 2005 to evaluate cantaloupe tolerance to rimsulfuron and halosulfuron applied to cantaloupe at the two-leaf stage, five- to six-leaf stage, plants having 30- to 40-cm vines, and plants having up to 5-cm-diam melons. Additionally, control of eight weed species was evaluated in these trials in 2005. Cantaloupe plant injury from rimsulfuron differed among application timings and trials, but applications were generally more injurious when applied at the two early crop stages. Halosulfuron was less injurious to cantaloupe, but 31 and 14% injury occurred following the two-leaf and five- to six-leaf applications, respectively, in the second trial in 2005. In the first trial of 2005, number of marketable melons the first week of harvest was lower for all halosulfuron applications compared with the nontreated control (30 to 37% reduction). In the second trial of 2005, total number of marketable melons was comparable to the nontreated control for each of the halosulfuron treatments, except the five- to six-leaf and up to 5-cm-diam melon applications. Injury estimates were poor indicators of occurrence or absence of delays in crop earliness or number of marketable melons. Rimsulfuron was generally effective (≥ 80% control) in controlling seedling Texas panicum, large crabgrass, tall morningglory, pitted morningglory, and Palmer amaranth, but was ineffective against yellow and purple nutsedge and goosegrass. Halosulfuron was effective in controlling yellow and purple nutsedge, but was ineffective against Texas panicum, large crabgrass, goosegrass, pitted morningglory, tall morningglory, and Palmer amaranth.

Absorption, Translocation, and Metabolism of Glufosinate in Transgenic and Nontransgenic Cotton, Palmer Amaranth (Amaranthus palmeri), and Pitted Morningglory (Ipomoea lacunosa)

Weed Science ◽  
2009 ◽  
Vol 57 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Wesley J. Everman ◽  
Walter E. Thomas ◽  
James D. Burton ◽  
Alan C. York ◽  
John W. Wilcut
Keyword(s):  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Weed Species ◽  
Ipomoea Lacunosa ◽  
Leaf Stage ◽  
Intermediate Metabolism ◽  
Pitted Morningglory ◽  
Cotton Plants ◽  
Treated Leaf ◽  
Harvest Intervals

Greenhouse studies were conducted to evaluate absorption, translocation, and metabolism of14C-glufosinate in glufosinate-resistant cotton, nontransgenic cotton, Palmer amaranth, and pitted morningglory. Cotton plants were treated at the four-leaf stage, whereas Palmer amaranth and pitted morningglory were treated at 7.5 and 10 cm, respectively. All plants were harvested at 1, 6, 24, 48, and 72 h after treatment (HAT). Absorption of14C-glufosinate was greater than 85% 24 h after treatment in Palmer amaranth. Absorption was less than 30% at all harvest intervals for glufosinate-resistant cotton, nontransgenic cotton, and pitted morningglory. At 24 HAT, 49 and 12% of radioactivity was translocated to regions above and below the treated leaf, respectively, in Palmer amaranth. Metabolites of14C-glufosinate were detected in all crop and weed species. Metabolism of14C-glufosinate was 16% or lower in nontransgenic cotton and pitted morningglory; however, metabolism rates were greater than 70% in glufosinate-resistant cotton 72 HAT. Intermediate metabolism was observed for Palmer amaranth, with metabolites comprising 20 to 30% of detectable radioactivity between 6 and 72 HAT.

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