Response of grain sorghum to low rates of glufosinate and nicosulfuron

Abstract Previous research has shown that glufosinate and nicosulfuron at low rates can cause yield loss to grain sorghum. However, research has not been conducted to pinpoint the growth stage at which these herbicides are most injurious to grain sorghum. Therefore, field tests were conducted in 2016 and 2017 to determine the most sensitive growth stage for grain sorghum exposure to both glufosinate and nicosulfuron. Field test were designed with factor A being the herbicide applied (glufosinate or nicosulfuron). Factor B consisted of timing of herbicide application including V3, V8, flagleaf, heading, and soft dough stages. Factor C was glufosinate or nicosulfuron rate where a proportional rate of 656 g ai ha−1 of glufosinate and 35 g ai ha−1 of nicosulfuron was applied at 1/10×, 1/50×, and 1/250×. Visible injury, crop canopy heights (cm), and yield were reported as a percent of the nontreated. At the V3 growth stage visible injury of 32% from the 1/10× rate of glufosinate and 51% from the 1/10× rate of nicosulfuron was observed. This injury was reduced by 4 wk after application (WAA) and no yield loss occurred. Nicosulfuron was more injurious than glufosinate at a 1/10× and 1/50× rate when applied at the V8 and flagleaf growth stages resulting in death of the shoot, reduced heading, and yield. Yield losses from the 1/10× rate of nicosulfuron were observed from V8 through early heading and ranged from 41% to 96%. Yield losses from the 1/50× rate of nicosulfuron were 14% to 16% at the flagleaf and V8 growth stages respectively. The 1/10× rate of glufosinate caused 36% visible injury 2 WAA when applied at the flagleaf stage, which resulted in a 16% yield reduction. By 4 WAA visible injury from either herbicide at less than the 1/10× rate was not greater than 4%. Results indicate that injury can occur, but yield losses are more probable from low rates of nicosulfuron at V8 and flagleaf growth stages.

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Impact of Brown Spot Caused by Septoria glycines on Soybean in Ohio

Plant Disease ◽

10.1094/pdis-94-7-0820 ◽

2010 ◽

Vol 94 (7) ◽

pp. 820-826 ◽

Cited By ~ 25

Author(s):

Christian D. Cruz ◽

Dennis Mills ◽

Pierce A. Paul ◽

Anne E. Dorrance

Keyword(s):

Growth Stage ◽

Yield Loss ◽

Management Program ◽

Brown Spot ◽

Growth Stages ◽

Yield Losses ◽

Cultivar Development ◽

Term Management ◽

Different Levels

Brown spot, caused by Septoria glycines, is the most common foliar disease of soybean in Ohio, but its economic impact has not been assessed on modern cultivars. Therefore, the objectives of this study were to (i) evaluate the effect of S. glycines on soybean yield and (ii) evaluate the efficacy of strobilurin- and triazole-based fungicides on the control of brown spot. Yield loss associated with S. glycines was determined using weekly applications of chlorothalonil. The efficacy of azoxystrobin, pyraclostrobin, tebuconazole, and flutriafol alone and in combinations were also assessed using applications at the R3 and R5 growth stages at two locations over 3 years. Significantly different levels of brown spot developed following applications of chlorothalonil, with mean yield differences between treated and nontreated plots ranging from 196 to 293 kg/ha. Pyraclostrobin and azoxystrobin applied at the R3 growth stage significantly reduced final levels of brown spot; however, significant increases in yield occurred in only three of the six location-years. Triazoles, flutriafol and tebuconazole, applied at R3 or R5 did not significantly decrease levels of brown spot or impact yield. More data on the accurate timing of fungicides are still required to establish a long-term management program for this disease, and resistance to brown spot should be monitored in soybean cultivar development to prevent future yield losses.

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Corn (Zea mays L.) response to sublethal rates of paraquat and fomesafen at vegetative growth stages

Weed Technology ◽

10.1017/wet.2019.28 ◽

2019 ◽

Vol 33 (04) ◽

pp. 595-600

Author(s):

Benjamin P. Sperry ◽

Benjamin H. Lawrence ◽

Jason A. Bond ◽

Daniel B. Reynolds ◽

Bobby R. Golden ◽

...

Keyword(s):

Growth Stage ◽

Yield Loss ◽

Zea Mays L ◽

Growth Stages ◽

Corn Yield ◽

Internode Elongation ◽

Yield Losses ◽

Target Movement ◽

Significant Injury ◽

Over Time

AbstractResearch was conducted from 2013 to 2015 across three sites in Mississippi to evaluate corn response to sublethal paraquat or fomesafen (105 and 35 g ai ha−1, respectively) applied PRE, or to corn at the V1, V3, V5, V7, or V9 growth stages. Fomesafen injury to corn at three d after treatment (DAT) ranged from 0% to 38%, and declined over time. Compared with the nontreated control (NTC), corn height 14 DAT was reduced approximately 15% due to fomesafen exposure at V5 or V7. Exposure at V1 or V7 resulted in 1,220 and 1,110 kg ha−1 yield losses, respectively, compared with the NTC, but yield losses were not observed at any other growth stage. Fomesafen exposure at any growth stage did not affect corn ear length or number of kernel rows relative to the NTC. Paraquat injury to corn ranged from 26% to 65%, depending on growth stage and evaluation interval. Corn exposure to paraquat at V3 or V5 consistently caused greater injury across evaluation intervals, compared with other growth stages. POST timings of paraquat exposure resulted in corn height reductions of 13% to 50%, except at V7, which was most likely due to rapid internode elongation at that stage. Likewise, yield loss occurred after all exposure times of paraquat except PRE, compared with the NTC. Corn yield was reduced 1,740 to 5,120 kg ha−1 compared with the NTC, generally worsening as exposure time was delayed. Paraquat exposure did not reduce corn ear length, compared with the NTC, at any growth stage. However, paraquat exposure at V3 or V5 was associated with reduction of kernel rows by 1.1 and 1.7, respectively, relative to the NTC. Paraquat and fomesafen applications near corn should be avoided if conditions are conducive for off-target movement, because significant injury and yield loss can result.

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Response of Acetolactate Synthase–Resistant Grain Sorghum to Nicosulfuron Plus Rimsulfuron

Weed Technology ◽

10.1614/wt-d-09-00061.1 ◽

2010 ◽

Vol 24 (4) ◽

pp. 411-415 ◽

Cited By ~ 5

Author(s):

D. Shane Hennigh ◽

Kassim Al-Khatib ◽

Mitchell R. Tuinstra

Keyword(s):

Grain Yield ◽

Plant Height ◽

Field Experiments ◽

Acetolactate Synthase ◽

Grain Sorghum ◽

Yield Reduction ◽

Growth Stages ◽

Visible Injury ◽

Leaf Stage ◽

Sorghum Grain

The lack of POST herbicides to control grasses in grain sorghum prompted researchers to develop acetolactate synthase (ALS)–resistant grain sorghum. Field experiments were conducted to evaluate the differential response of ALS-resistant grain sorghum to POST application of nicosulfuron + rimsulfuron applied at three growth stages. ALS-resistant grain sorghum was treated with 0, 13 + 7, 26 + 13, 39 + 20, 52 + 26, 65 + 33, 78 + 39, and 91 + 46 g ai ha−1of nicosulfuron + rimsulfuron when plants were at the three- to five-leaf, seven- to nine-leaf, or 11- to 13-leaf stage. In general, as nicosulfuron + rimsulfuron rates increased, visible injury increased at the three- to five-leaf and seven- to nine-leaf stages. Injury was greatest 1 wk after treatment for the three- to five-leaf and seven- to nine-leaf stages across all ratings, and plants then began to recover. No injury was observed at any rating time for the 11- to 13-leaf stage. Plant height and sorghum grain yield were reduced as nicosulfuron + rimsulfuron rates increased when applied at the three- to five-leaf stage. However, nicosulfuron + rimsulfuron applied at the seven- to nine-leaf and 11- to 13-leaf stages did not decrease sorghum yield. This research indicated that nicosulfuron + rimsulfuron application at the three- to five-leaf stage injured ALS-resistant grain sorghum; however, application at the seven- to nine-leaf or 11- to 13-leaf stages did not result in grain yield reduction.

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Effect of soybean growth stage on sensitivity to sublethal rates of dicamba and 2,4-D

Weed Technology ◽

10.1017/wet.2019.39 ◽

2019 ◽

Vol 33 (04) ◽

pp. 555-561 ◽

Cited By ~ 4

Author(s):

Alanna B. Scholtes ◽

Benjamin P. Sperry ◽

Daniel B. Reynolds ◽

J. Trenton Irby ◽

Thomas W. Eubank ◽

...

Keyword(s):

Growth Stage ◽

Field Experiments ◽

Yield Loss ◽

Specific Growth ◽

Growth Stages ◽

Growing Degree Days ◽

Multiple Exposure ◽

Degree Days ◽

Target Movement ◽

Visible Injury

AbstractField experiments were conducted in 2012 and 2013 across four locations for a total of 6 site-years in the midsouthern United States to determine the effect of growth stage at exposure on soybean sensitivity to sublethal rates of dicamba (8.8 g ae ha−1) and 2,4-D (140 g ae ha−1). Regression analysis revealed that soybean was most susceptible to injury from 2,4-D when exposed between 413 and 1,391 accumulated growing degree days (GDD) from planting, approximately between V1 and R2 growth stages. In terms of terminal plant height, soybean was most susceptible to 2,4-D between 448 and 1,719 GDD, or from V1 to R4. However, maximum susceptibility to 2,4-D was only between 624 and 1,001 GDD or from V3 to V5 for yield loss. As expected, soybean was sensitive to dicamba for longer spans of time, ranging from 0 to 1,162 GDD for visible injury or from emergence to R2. Likewise, soybean height was most affected when dicamba exposure occurred between 847 and 1,276 GDD or from V4 to R2. Regarding grain yield, soybean was most susceptible to dicamba between 820 and 1,339 GDD or from V4 to R2. Consequently, these data indicate that soybean response to 2,4-D and dicamba can be variable within vegetative or reproductive growth stages; therefore, specific growth stage at the time of exposure should be considered when evaluating injury from off-target movement. In addition, application of dicamba near susceptible soybean within the V4 to R2 growth stages should be avoided because this is the time of maximum susceptibility. Research regarding soybean sensitivity to 2,4-D and dicamba should focus on multiple exposure times and also avoid generalizing growth stages to vegetative or reproductive.

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Preemergence herbicide delays the critical time of weed removal in popcorn

Weed Technology ◽

10.1017/wet.2019.58 ◽

2019 ◽

Vol 33 (6) ◽

pp. 785-793 ◽

Cited By ~ 2

Author(s):

Ethann R. Barnes ◽

Stevan Z. Knezevic ◽

Nevin C. Lawrence ◽

Suat Irmak ◽

Oscar Rodriguez ◽

...

Keyword(s):

Growth Stage ◽

Yield Loss ◽

Critical Time ◽

Yield Reduction ◽

Growth Stages ◽

Growing Degree Days ◽

Degree Days ◽

South Central ◽

Main Plot ◽

Weed Removal

AbstractUnderstanding the critical time of weed removal (CTWR) is necessary for designing effective weed management programs in popcorn production that do not result in yield reduction. The objective of this study was to determine the CTWR in popcorn with and without a premix of atrazine and S-metolachlor applied PRE. Field experiments were conducted at the University of Nebraska–Lincoln, South Central Agricultural Laboratory near Clay Center, NE in 2017 and 2018. The experiment was laid out in a split-plot design with PRE herbicide as the main plot and weed removal timing as the subplot. Main plots included no herbicide or atrazine/S-metolachlor applied PRE. Subplot treatments included a weed-free control, a non-treated control, and weed removal timing at V3, V6, V9, V15, and R1 popcorn growth stages and then kept weed free throughout the season. A four-parameter log-logistic function was fitted to percentage popcorn yield loss and growing degree days separately to each main plot. The number of growing degree days, when 5% yield loss was achieved, was extracted from the model and compared between main plots. The CTWR was from the V4 to V5 popcorn growth stage in absence of PRE herbicide. With atrazine/S-metolachlor applied PRE, the CTWR was delayed until V10 to V15. It is concluded that, to avoid yield loss, weeds must be controlled before the V4 popcorn growth stage when no PRE herbicide is applied, and PRE herbicide, such as atrazine/S-metolachlor in this study, can delay the CTWR until the V10 growth stage.

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Sensitivity and Recovery of Grain Sorghum to Simulated Drift Rates of Glyphosate, Glufosinate, and Paraquat

Agriculture ◽

10.3390/agriculture9040070 ◽

2019 ◽

Vol 9 (4) ◽

pp. 70 ◽

Cited By ~ 1

Author(s):

Ralph Hale ◽

Taghi Bararpour ◽

Gurpreet Kaur ◽

John Seale ◽

Bhupinder Singh ◽

...

Keyword(s):

Growth Stage ◽

Leaf Growth ◽

Flag Leaf ◽

Grain Sorghum ◽

Yield Reduction ◽

Leaf Stage ◽

Herbicide Treatments ◽

Significant Yield ◽

Glyphosate Drift ◽

Herbicide Drift

A field experiment was conducted in 2017 and 2018 to evaluate the sensitivity and recovery of grain sorghum to the simulated drift of glufosinate, glyphosate, and paraquat at two application timings (V6 and flag leaf growth stage). Paraquat drift caused maximum injury to sorghum plants in both years, whereas the lowest injury was caused by glyphosate in 2017. Averaged over all herbicide treatments, injury to grain sorghum from the simulated herbicide drift was 5% greater when herbicides were applied at flag leaf stage, as compared to herbicide applications at the six-leaf stage in 2017. In 2018, injury from glyphosate drift was higher when applied at the six-leaf stage than at the flag leaf stage. Paraquat and glufosinate drift caused more injury when applied at flag leaf stage than at six-leaf stage at 14 days after application in 2018. About 21% to 29% of injury from the simulated drift of paraquat led to a 31% reduction in grain sorghum yield, as compared to a nontreated check in 2017. The simulated drift of glyphosate and glufosinate did not result in any significant yield reduction compared to the nontreated check in 2017, possibly due to the recovery of sorghum plants after herbicides’ drift application.

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Corn Yield Loss Due to Volunteer Soybean

Weed Science ◽

10.1614/ws-d-16-00004.1 ◽

2016 ◽

Vol 64 (3) ◽

pp. 495-500 ◽

Cited By ~ 3

Author(s):

Jill Alms ◽

Sharon A. Clay ◽

David Vos ◽

Michael Moechnig

Keyword(s):

Loss Function ◽

Growth Stage ◽

Yield Loss ◽

Corn Yield ◽

Yield Losses ◽

Herbicide Resistant ◽

Growing Seasons ◽

Previous Season ◽

Control Volunteer ◽

Soybean Plants

The widespread adoption of glyphosate-resistant corn and soybean in cropping rotations often results in volunteer plants from the previous season becoming problem weeds that require alternative herbicides for control. Corn yield losses due to season-long volunteer soybean competition at several densities in two growing seasons were used to define a hyperbolic yield loss function. The maximum corn yield loss observed at high volunteer soybean densities was about 56%, whereas, the incremental yield loss (I) at low densities was 3.2%. Corn yield loss at low volunteer soybean densities was similar to losses reported for low densities of velvetleaf and redroot pigweed, with 10% yield loss estimated to occur at 3 to 4 volunteer soybean plants m−2. Several herbicides, including dicamba with or without diflufenzopyr applied at the V2 growth stage of volunteer soybean, provided > 90% control, demonstrating several economical options to control volunteer glyphosate-resistant soybean in glyphosate-resistant corn. Reevaluation of control recommendations may be needed with commercialization of other genetically modified herbicide-resistant soybean varieties.

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Dwarf sunflower response to row spacing, stand reduction, and defoliation at different growth stages

Canadian Journal of Plant Science ◽

10.4141/p02-031 ◽

2003 ◽

Vol 83 (2) ◽

pp. 319-326 ◽

Cited By ~ 1

Author(s):

B. L. Johnson

Keyword(s):

Helianthus Annuus ◽

Oil Content ◽

Growth Stage ◽

Total Yield ◽

Reciprocal Relationship ◽

Yield Response ◽

Yield Reduction ◽

Row Spacing ◽

Growth Stages ◽

Helianthus Annuus L

Growth compensation of dwarf sunflower (Helianthus annuus L.) hybrids to low initial stands, later stand losses, or plant defoliation has not been reported regarding replanting decisions and crop insurance yield loss assessment. Three experiments were conducted to study the affect of stand reduction, defoliation, and row spacing on dwarf sunflower yield and quality when grown in eastern North Dakota. Experiment 1 evaluated stand reduction (0, 25, 50 and 75%) applied at growth stages (V4, R1 and R6) in 15, 45 and 76 cm spaced rows. Row spacing interactions with stand reduction and growth stage were not significant for yield indicating growth stage and stand reduction effects on yield response were independent of row spacing. In exp. 2, significant growth stage (V4, V8, R1, R2, R3, R5 and R6) by stand reduction (0, 12, 25, 37, 50, 62 and 75%) interaction showed stand reduction at vegetative growth stages not influencing yield, but as maturity progressed yield reductions became greater with increased stand reduction. Achene weight increased with increasing stand reduction at vegetative and early reproductive stages. A reciprocal relationship was noted between achene weight and achene oil content where oil content decreased as achene weight increased. Interaction of growth stage (R1 and R6) and defoliation (0, 25, 50, 75 and 100%) in exp. 3 indicated greater reduction in yield, test weight, 1000-achene weight, and achene oil conte nt as defoliatin increased at growth stage R6. Yield compensating ability of dwarf sunflower is dependent on type and level of damage and growth stage of occurrence, with total yield reduction considering all effects. Key words: Sunflower, Helianthus annuus L., row spacing, stand reduction, defoliation

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The critical weed-free period in glyphosate-resistant soybean in Ontario is similar to previous estimates using glyphosate-susceptible soybean

Canadian Journal of Plant Science ◽

10.1139/cjps-2018-0049 ◽

2019 ◽

Vol 99 (4) ◽

pp. 437-443

Author(s):

Nader Soltani ◽

Robert E. Nurse ◽

Amit J. Jhala ◽

Peter H. Sikkema

Keyword(s):

Growth Stage ◽

Field Experiments ◽

Yield Loss ◽

Growth Stages ◽

Weed Species ◽

Weed Biomass ◽

Weed Density ◽

Weed Interference ◽

Beginning Of Flowering ◽

Minimal Reduction

A study consisting of 13 field experiments was conducted during 2014–2016 in southwestern Ontario and southcentral Nebraska (Clay Center) to determine the effect of late-emerging weeds on the yield of glyphosate-resistant soybean. Soybean was maintained weed-free with glyphosate (900 g ae ha−1) up to the VC (cotyledon), V1 (first trifoliate), V2 (second trifoliate), V3 (third trifoliate), V4 (fourth trifoliate), and R1 (beginning of flowering) growth stages, after which weeds were allowed to naturally infest the soybean plots. The total weed density was reduced to 24%, 63%, 67%, 72%, 76%, and 92% in Environment 1 (Exeter, Harrow, and Ridgetown) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 soybean growth stages, respectively. The total weed biomass was reduced by 33%, 82%, 95%, 97%, 97%, and 100% in Environment 1 (Exeter, Harrow, and Ridgetown) and 28%, 100%, 100%, 100%, 100%, and 100% in Environment 2 (Clay Center) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 stages, respectively. The critical weed-free periods for a 2.5%, 5%, and 10% yield loss in soybean were the V1–V2, VC–V1, and VC–V1 soybean stages in Environment 1 (Exeter, Harrow, and Ridgetown) and V2–V3, V2–V3, and V1–V2 soybean stages in Environment 2 (Clay Center), respectively. For the weed species evaluated, there was a minimal reduction in weed biomass (5% or less) when soybean was maintained weed-free beyond the V3 soybean growth stage. These results shows that soybean must be maintained weed-free up to the V3 growth stage to minimize yield loss due to weed interference.

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The effect of cotton growth stage on response to a sublethal concentration of 2,4-D

Weed Technology ◽

10.1017/wet.2019.9 ◽

2019 ◽

Vol 33 (2) ◽

pp. 321-328 ◽

Cited By ~ 1

Author(s):

John T. Buol ◽

Daniel B. Reynolds ◽

Darrin M. Dodds ◽

J. Anthony Mills ◽

Robert L. Nichols ◽

...

Keyword(s):

Fiber Length ◽

Growth Stage ◽

Field Experiments ◽

Fruit Set ◽

Sublethal Concentration ◽

Growth Stages ◽

Visible Injury ◽

Fiber Properties ◽

Low Concentrations ◽

Auxin Herbicides

AbstractRecent commercialization of auxin herbicide–based weed control systems has led to increased off-target exposure of susceptible cotton cultivars to auxin herbicides. Off-target deposition of dilute concentrations of auxin herbicides can occur on cotton at any stage of growth. Field experiments were conducted at two locations in Mississippi from 2014 to 2016 to assess the response of cotton at various growth stages after exposure to a sublethal 2,4-D concentration of 8.3 g ae ha−1. Herbicide applications occurred weekly from 0 to 14 weeks after emergence (WAE). Cotton exposure to 2,4-D at 2 to 9 WAE resulted in up to 64% visible injury, whereas 2,4-D exposure 5 to 6 WAE resulted in machine-harvested yield reductions of 18% to 21%. Cotton maturity was delayed after exposure 2 to 10 WAE, and height was increased from exposure 6 to 9 WAE due to decreased fruit set after exposure. Total hand-harvested yield was reduced from 2,4-D exposure 3, 5 to 8, and 13 WAE. Growth stage at time of exposure influenced the distribution of yield by node and position. Yield on lower and inner fruiting sites generally decreased from exposure, and yield partitioned to vegetative or aborted positions and upper fruiting sites increased. Reductions in gin turnout, micronaire, fiber length, fiber-length uniformity, and fiber elongation were observed after exposure at certain growth stages, but the overall effects on fiber properties were small. These results indicate that cotton is most sensitive to low concentrations of 2,4-D during late vegetative and squaring growth stages.

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