scholarly journals Off-Target Movement of Diglycolamine Dicamba to Non-dicamba Soybean Using Practices to Minimize Primary Drift

2019 ◽  
Vol 33 (1) ◽  
pp. 24-40 ◽  
Author(s):  
Gordon T. Jones ◽  
Jason K. Norsworthy ◽  
Tom Barber
Keyword(s):  
New Technology ◽  
Field Studies ◽  
The United States ◽  
Yield Reduction ◽  
Growth Stages ◽  
Target Movement ◽  
Soybean Yield ◽  
Wind Speeds ◽  
Height Reduction ◽  
Over The Top

AbstractSoybean with resistance to dicamba (DR soybean) and glyphosate and cotton with resistance to glyphosate, glufosinate, and dicamba were recently commercialized in the United States and have been readily adopted. To evaluate results of over-the-top application of dicamba in DR crops, field studies were designed to examine off-target movement using proposed sprayer setup recommendations. Association analysis and nonlinear regression techniques were used to examine the effects of 26 field-scale drift trials conducted in 2014 and 2015 during soybean reproductive development (R1 through R6). The greatest predictors (injury, height reduction) of soybean yield reduction generally occurred and had steeper relationships after drift events at the R1 growth stage than at later stages. Using non-DR soybean as an indicator, dicamba was documented to move as much as 152 m from the application area (distance to 5% injury). Instances of height reduction (5%) differed among growth stages, with the greatest distance occurring at R1 (83.4 m). Soybean yield reduction was erratic, with the greatest distance to 5% loss in yield occurring at 42.8 m after an R1 drift event. Overall, the data suggest flowering-stage soybean is more sensitive than later reproductive soybean to injury, height reductions, and yield loss. Average and maximum wind speeds did not account for the injury documented from dicamba, and it is hypothesized that other meteorological variables also play a notable role in dicamba off-target movement as well as growing conditions following exposure. With concerns surrounding off-target movement of dicamba, proper stewardship of this new technology will be key to its longevity.

Evaluation of dicamba retention in spray tanks and its impact on flue-cured tobacco

2020 ◽  
pp. 1-8
Author(s):  
Matthew D. Inman ◽  
Matthew C. Vann ◽  
Loren R. Fisher ◽  
Travis W. Gannon ◽  
David L. Jordan ◽  
...  
Keyword(s):  
Maximum Yield ◽  
Field Studies ◽  
The United States ◽  
Yield Reduction ◽  
Target Movement ◽  
Application Timing ◽  
Significant Relationships ◽  
Cleaning Procedures ◽  
Injury Assessment ◽  
Auxin Herbicides

Abstract In recent years, there has been increased use of dicamba due to the introduction of dicamba-resistant cotton and soybean in the United States. Therefore, there is a potential increase in off-target movement of dicamba and injury to sensitive crops. Flue-cured tobacco is extremely sensitive to auxin herbicides, particularly dicamba. In addition to yield loss, residue from drift or equipment contamination can have severe repercussions for the marketability of the crop. Studies were conducted in 2016, 2017, and 2018 in North Carolina to evaluate spray-tank cleanout efficiency of dicamba using various cleaning procedures. No difference in dicamba recovery was observed regardless of dicamba formulation and cleaning agent. Dicamba residue decreased with the number of rinses. There was no difference in dicamba residue recovered from the third rinse compared with residue from the tank after being refilled for subsequent tank use. Recovery ranged from 2% to 19% of the original concentration rate among the three rinses. Field studies were also conducted in 2018 to evaluate flue-cured tobacco response to reduced rates of dicamba ranging, from 1/5 to 1/10,000 of a labeled rate. Injury and yield reductions varied by environment and application timing. When exposed to 1/500 of a labeled rate at 7 and 11 wk after transplanting, tobacco injury ranged from 39% to 53% and 10% to 16% 24 days after application, respectively. The maximum yield reduction was 62%, with a 55% reduction in value when exposed to 112 g ha−1 of dicamba. Correlations showed significant relationships between crop injury assessment and yield and value reductions, with Pearson values ranging from 0.24 to 0.63. These data can provide guidance to growers and stakeholders and emphasize the need for diligent stewardship when using dicamba technology.

Soybean Sensitivity to Florpyrauxifen-benzyl during Reproductive Growth and the Impact on Subsequent Progeny

2017 ◽  
Vol 32 (2) ◽  
pp. 135-140 ◽  
Author(s):  
M. Ryan Miller ◽  
Jason K. Norsworthy
Keyword(s):  
Plant Height ◽  
Field Studies ◽  
Yield Reduction ◽  
Growth Stages ◽  
Soybean Plant ◽  
Reproductive Growth ◽  
Similar Reduction ◽  
Structural Class ◽  
Soybean Plants ◽  
The Impact

AbstractTo address recent concerns related to auxin herbicide drift onto soybean, a study was developed to understand the susceptibility of the reproductive stage of soybean to a new auxin herbicide compared with dicamba. Florpyrauxifen-benzyl is under development as the second herbicide in a new structural class of synthetic auxins, the arylpicolinates. Field studies were conducted to (1) evaluate and compare reproductive soybean injury and yield following applications of florpyrauxifen-benzyl or dicamba across various concentrations and reproductive growth stages and (2) determine whether low-rate applications of florpyrauxifen-benzyl or dicamba to soybean in reproductive stages would have similar effect on the progeny of the affected plants. Soybean were treated with 0, 1/20, or 1/160, of the 1X rate of florpyrauxifen-benzyl (30 g ai ha−1) or dicamba (560 g ae ha−1) at R1, R2, R3, R4, or R5 growth stage. Soybean plant height and yield was reduced from 1/20X dicamba across all reproductive stages. High drift rates (1/20X) of florpyrauxifen-benzyl also reduced soybean plant height >25% and yield across R1 to R4 stages. Germination, stand, plant height, and yield of the offspring of soybean plants treated with dicamba and florpyrauxifen-benzyl were significantly affected. Dicamba applied at a rate of 1/20X at R4 and R5 resulted in 20% and 35% yield reduction for the offspring, respectively. A similar reduction occurred from florpyrauxifen-benzyl applied at R4 and R5 at the 1/20X rate, resulting in 15% to 24% yield reduction for the offspring, respectively. Based on these findings, it is suggested that growers use caution when applying these herbicides in the vicinity of reproductive soybean.

scholarly journals Soybean yield, biological N2 fixation and seed composition responses to additional inoculation in the United States

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Walter D. Carciochi ◽  
Luiz H. Moro Rosso ◽  
Mario A. Secchi ◽  
Adalgisa R. Torres ◽  
Seth Naeve ◽  
...  
Keyword(s):  
Seed Yield ◽  
Previous History ◽  
Soybean Seed ◽  
The United States ◽  
Growth Stages ◽  
Seed Composition ◽  
Soybean Yield ◽  
Nodule Number ◽  
Soil Inoculation ◽  
Seed Inoculation

AbstractIt is unclear if additional inoculation with Bradyrhizobia at varying soybean [Glycine max (L.) Merr.] growth stages can impact biological nitrogen fixation (BNF), increase yield and improve seed composition [protein, oil, and amino acid (AA) concentrations]. The objectives of this study were to evaluate the effect of different soybean inoculation strategies (seed coating and additional soil inoculation at V4 or R1) on: (i) seed yield, (ii) seed composition, and (iii) BNF traits [nodule number and relative abundance of ureides (RAU)]. Soybean field trials were conducted in 11 environments (four states of the US) to evaluate four treatments: (i) control without inoculation, (ii) seed inoculation, (iii) seed inoculation + soil inoculation at V4, and (iv) seed inoculation + soil inoculation at R1. Results demonstrated no effect of seed or additional soil inoculation at V4 or R1 on either soybean seed yield or composition. Also, inoculation strategies produced similar values to the non-inoculated control in terms of nodule number and RAU, a reflection of BNF. Therefore, we conclude that in soils with previous history of soybean and under non-severe stress conditions (e.g. high early-season temperature and/or saturated soils), there is no benefit to implementing additional inoculation on soybean yield and seed composition.

Growth Stage Affects Cotton Response to Trifloxysulfuron

2007 ◽  
Vol 21 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Robert J. Richardson ◽  
Henry P. Wilson ◽  
Gregory R. Armel ◽  
Thomas E. Hines
Keyword(s):  
Nonionic Surfactant ◽  
Growth Stage ◽  
Fiber Quality ◽  
Field Studies ◽  
Growth Stages ◽  
Cotton Yield ◽  
Cotton Crop ◽  
Application Timing ◽  
Crop Injury ◽  
Over The Top

Field studies were conducted in 1999, 2000, and 2001 to evaluate cotton response to trifloxysulfuron applied postemergence over the top (POT) or postemergence-directed (PDIR) at various growth stages. Treatments included trifloxysulfuron at 3.8 or 7.5 g ai/ha plus nonionic surfactant (NIS) applied POT to one-, three-, and five-leaf cotton or applied PDIR to 30- and 45-cm tall cotton. Crop injury 7 d after treatment (DAT) varied by year and ranged from 17 to 50%, 19 to 46%, and 5 to 23% with trifloxysulfuron applied POT to one-, three-, and five-leaf cotton, respectively. Injury 21DAT averaged 22, 16, and 6% with one-, three-, and five-leaf applications respectively. Trifloxysulfuron applied PDIR injured cotton 2 to 9% 7 DAT and 0 to 12% 21 DAT. At 30 DAT, cotton height was reduced with one-leaf trifloxysulfuron application, whereas differences were not present across other treatments. Heights at 90 days after planting (DAP) did not differ between treatments. Neither trifloxysulfuron rate or application timing negatively affected cotton yield or fiber quality.

Cotton (Gossypium hirsutum) Response to Simulated Triclopyr Drift

1991 ◽  
Vol 5 (3) ◽  
pp. 493-498 ◽  
Author(s):  
Charles E. Snipes ◽  
Joe E. Street ◽  
Thomas C. Mueller
Keyword(s):  
Gossypium Hirsutum ◽  
Yield Reduction ◽  
Growth Stages ◽  
Cotton Yield ◽  
Lag Period ◽  
Over The Top

Cotton response to triclopyr was evaluated when it was applied over-the-top at simulated drift rates to pin-head square and early bloom cotton growth stages in 1987 and 1988. The herbicidal effects of triclopyr were most evident after a lag period of 10 to 15 d. Triclopyr at 60 g ai ha-1applied at pin-head square reduced cotton height in 1987, but not in 1988. Triclopyr applied at pin-head square and early bloom reduced cotton flowering initially, as measured by white bloom counts, in both years. Total blooms were reduced in 1987, but not in 1988. Cotton maturity was delayed by triclopyr application during early bloom, as shown by a decrease in percent open bolls, and a decrease in first pick cotton yields. Cotton yield was lower in plots receiving triclopyr, with the greatest yield reduction caused by a 60 g ha-1triclopyr application at early bloom.

Integrated management of glyphosate-resistant horseweed (Erigeron canadensis) with tillage and herbicides in soybean

2019 ◽  
Vol 33 (6) ◽  
pp. 859-866 ◽  
Author(s):  
Parminder S. Chahal ◽  
Amit J. Jhala
Keyword(s):  
Integrated Management ◽  
Block Design ◽  
Integrated Approach ◽  
Field Studies ◽  
The United States ◽  
Soybean Yield ◽  
Growing Seasons ◽  
Two Factors ◽  
Sites Of Action

AbstractGlyphosate-resistant (GR) horseweed is one of the most common and troublesome weeds in soybean production fields in several states in the United States, including Nebraska. The evolution of horseweed resistant to several herbicide sites of action has prioritized an integrated approach, including tillage, for effective management of this problem weed. The objectives of this study were to evaluate the effect of tillage or herbicide applied in fall or spring followed by a PRE, POST, and PRE followed by a POST herbicide program for GR horseweed control as well as GR soybean injury and yield in Nebraska. Field studies were established in the fall 2014–2015 and 2015–2016 growing seasons using a factorial randomized complete block design with shallow tillage or herbicide applied at different timings as two factors. Shallow tillage was accomplished using a 50-cm-wide rototiller operated at a depth of 10 cm. At soybean harvest, tillage applied the previous year in fall or spring without any follow-up herbicide treatment provided 79% to 88% horseweed control compared with 27% and 56% control with 2,4-D plus carfentrazone applied in fall and spring, respectively. Tillage or herbicide applied in fall or spring followed by a PRE, POST, or PRE and POST herbicide provided 82% to 99% GR horseweed control at soybean harvest. Soybean yield in this study was similar in most treatments. Tillage or herbicide applied in fall or spring provided similar horseweed control and soybean yield when followed by a PRE, POST, or PRE and POST herbicide; therefore, fall- or spring-applied herbicides can be rotated with shallow tillage for integrated season-long horseweed management.

Soybean response to weed interference and defoliation

Weed Science ◽  
1999 ◽  
Vol 47 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Charles F. Grymes ◽  
James L. Griffin ◽  
David J. Boethel ◽  
B. Rogers Leonard ◽  
David L. Jordan ◽  
...  
Keyword(s):  
Seed Development ◽  
Field Experiments ◽  
Dry Weight ◽  
Yield Reduction ◽  
Growth Stages ◽  
Lower Yield ◽  
Full Bloom ◽  
Soybean Yield ◽  
Weed Interference ◽  
Hemp Sesbania

Field experiments were conducted in Louisiana over 2 yr to evaluate the influence of full-season interference from johnsongrass, common cocklebur, or hemp sesbania at densities of 2.5, 0.5, and 2.0 plants m–1of row, respectively, and simulated insect defoliation of soybean on weed and soybean growth. Defoliation at R2 (full bloom) and R5 (beginning seed development) soybean growth stages was accomplished by removal of zero, one, or two leaflets per soybean trifoliate, which approximated 0, 33, and 66% defoliation, respectively. Height and dry weight of all weeds were not affected by soybean defoliation level or defoliation stage. Soybean height 3 wk after defoliation at R5 was not influenced by weed interference, soybean defoliation level, or defoliation stage in either year. Averaged across soybean defoliation levels and stages in 1994, johnsongrass, common cocklebur, and hemp sesbania reduced soybean yields 30, 15, and 14%, respectively. In 1995, johnsongrass reduced soybean yield 35%. As soybean defoliation level increased, a linear decrease in soybean yield was observed. Averaged across weeds and soybean defoliation stages, 33 and 66% defoliation reduced soybean yield 6 and 20% in 1994 and 12 and 33% in 1995, respectively. Defoliation at R5 resulted in 10% lower yield than defoliation at R2 in one of two years. Yield reduction due to combinations of weeds and soybean defoliation was additive.

Conventional Soybean Plant and Progeny Response to Glyphosate

2004 ◽  
Vol 18 (3) ◽  
pp. 527-531 ◽  
Author(s):  
Jason K. Norsworthy
Keyword(s):  
Population Growth ◽  
Growth Stage ◽  
Field Studies ◽  
Growth And Yield ◽  
Yield Reduction ◽  
Growth Stages ◽  
Soybean Plant ◽  
Vegetative Development ◽  
Application Timing ◽  
Glyphosate Drift

Field studies were conducted to determine the sensitivity of conventional ‘Motte’ and ‘Pioneer 9831’ soybean to simulated glyphosate drift rates applied during vegetative and reproductive development and the effect of glyphosate on progeny. Glyphosate at 8, 84, and 420 g ae/ha was applied to soybean at the V3, V6, R2, and R5 growth stages. Glyphosate at 8 and 84 g/ha did not reduce soybean plant population, growth, or yield or cause deleterious effects on progeny, regardless of the growth stage at application. Soybean population, growth, and yield were reduced as much as 99 to 100% after application of 420 g/ha glyphosate at the V3 growth stage. Glyphosate at 420 g/ha applied at V6 was less detrimental to soybean compared with the V3 timing. Delaying the application of 420 g/ha glyphosate until R2 and R5 reduced soybean yields 22 to 49% and 43 to 44%, respectively. Soybean injury from 420 g/ha glyphosate was generally transient or less severe when applied at the V6 growth stage or later. However, 420 g/ha glyphosate at R5 (initial podfill) caused a 390 to 450 kg/ha yield reduction compared with the V6 application, which indicated greater soybean vulnerability to glyphosate drift during podfill than in the late-stage vegetative development. Although glyphosate at 420 g/ha was injurious to soybean, regardless of application timing, progeny was not affected.

scholarly journals Effectiveness of Resistance to Southern Root-knot Nematode in `Carolina Cayenne' Pepper in Greenhouse, Microplot, and Field Tests

1997 ◽  
Vol 122 (2) ◽  
pp. 200-204 ◽  
Author(s):  
J.A. Thies ◽  
J.D. Mueller ◽  
R.L. Fery
Keyword(s):  
High Resistance ◽  
Methyl Bromide ◽  
Field Tests ◽  
Field Studies ◽  
The United States ◽  
Yield Reduction ◽  
Root Knot Nematode ◽  
Nematode Reproduction ◽  
Management Measures ◽  
Southern Root Knot Nematode

The southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] is a serious pest of pepper (Capsicum annuum L.). Currently, methyl bromide is used for nematode control, but the pending withdrawal of this fumigant from the United States market has resulted in a need for effective alternative root-knot nematode management measures. We evaluated the effectiveness of resistance of `Carolina Cayenne' relative to the susceptible genotypes `Early Calwonder' and PA-136 in greenhouse, microplot, and field studies. In all tests, `Carolina Cayenne' exhibited exceptionally high resistance (minimal galling, minimal nematode reproduction, and no yield reduction) to M. incognita; `Early Calwonder' and PA-136 were highly susceptible. In a test conducted in a heavily infested field, `Carolina Cayenne' outyielded PA-136 by 339%. The exceptionally high resistance exhibited by `Carolina Cayenne' provides an alternative to methyl bromide and other fumigant nematicides for managing root-knot nematodes in pepper.

Carryover Potential of Pyrithiobac to Rotational Crops on a Mississippi Black Belt Region Clay Soil

1996 ◽  
Vol 10 (1) ◽  
pp. 140-144 ◽  
Author(s):  
Eric P. Webster ◽  
David R. Shaw
Keyword(s):  
Clay Soil ◽  
Field Studies ◽  
Grain Sorghum ◽  
Black Belt ◽  
Yield Reduction ◽  
Cotton Yield ◽  
Soybean Yield ◽  
Black Belt Region

Field studies were conducted on a Black Belt region clay soil to evaluate pyrithiobac injury to cotton and potential carryover to grain sorghum, soybean, and wheat. Pyrithiobac was applied PPI, PRE, POST at pinhead square, or POST at first bloom at rates of 70, 140, or 280 g ai/ha to cotton. Cotton injury was 7% or less at all rates and application timings. Cotton yield was not reduced by any treatment. The PRE application to cotton, averaged over rates, reduced yield of wheat planted in the fall compared to the POST pinhead square application or the nontreated check. Pyrithiobac at 140 g/ha applied PPI to cotton the previous year reduced soybean yield; at all other rates and timings no soybean yield reduction occurred compared to the nontreated check. Pyrithiobac at all rates applied PPI to cotton caused grain sorghum injury the following year. The 280 g/ha PPI application delayed grain sorghum maturity; however, this did not translate into a yield reduction.

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