Relative sensitivity of conventional soybean to three dicamba based herbicides at different growth stages

Widespread use of dicamba-based herbicides such as Clarity® (dicamba diglycolamine salt, 480 g l-1), Engenia® (dicamba N,N-Bis-[3-aminopropyl] methylamine salt, 600 g l-1) and XtendiMax® (dicamba diglycolamine salt, 350 g l-1)with Vapor-Grip Technology for weed control in dicamba-tolerant (DT) crops have resulted in UN-intended drifts, partly due to windy and common temperature inversions in many parts of United States. It is unclear if the dicamba-based herbicides made of different formulations or technologies have differential impact on sensitive soybeans including a conventional variety. Thus, field studies were conducted in 2016 and 2017 to evaluate the relative sensitivity of a conventional soybean to micro-rates of three dicamba-based herbicide products (Clarity®, Engenia® and XtendiMax® ) applied at second trifoliate (V2), seventh trifoliate/beginning of flowering (V7/R1), and full flowering (R2) stages of soybean. The dicamba micro-rates were 0, 0.56, 1.12, 5.6, 11.2, and 56 g ae ha-1; equivalent to 0, 1/1000, 1/500, 1/100, 1/50, 1/10 of the standard rate (560 g ae ha-1) respectively. The experimental design was a randomized complete block design in a split-split-plot arrangement with 4 replications. There was no significant difference in visual injury, growth or yield response of the conventional soybean to the three dicamba herbicides. The dicamba micro rates caused 40-80% visual injury and 0-97% yield loss depending on the growth stage of application. The estimated effective doses (ED values) suggested that conventional soybeans exposed to dicamba micro-rates at V7/R1 growth stage were more sensitive than those exposed at V2 and R2 growth stages. Based on the ED values, about 0.1% of dicamba standard rate was enough to cause 10% soybean yield loss when applied at V7/R1 stage; while about 1% of dicamba standard rate was required to cause the same level of yield loss when applied at V2 or R2 stage. By implication, dicamba drift on sensitive soybean plants should be avoided to prevent yield loss.

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Corn (Zea mays L.) Response to Hybrid, Row Spacing, and Plant Populations in the Blacklands of Central Texas

JOURNAL OF ADVANCES IN AGRICULTURE ◽

10.24297/jaa.v8i1.7094 ◽

2018 ◽

Vol 8 ◽

pp. 1214-1223 ◽

Cited By ~ 1

Author(s):

James Grichar

Keyword(s):

Block Design ◽

Field Studies ◽

Growth And Yield ◽

Yield Response ◽

Row Spacing ◽

Plant Populations ◽

Corn Hybrids ◽

Significant Difference ◽

Central Texas ◽

Ear Height

Field studies were conducted during the 2013 and 2014 growing seasons in central Texas near Taylor (30.5326o N; 97.4548o W) to determine the effect of hybrid, row spacing, and plant populations on corn growth and yield. Two corn hybrids (BH 8844 and BH 8900) were compared at 53,000, 62,000, and 71,000 plants ha-1 planted one row on a single bed or twin rows (spaced approximately 20 cm apart) on a single bed. Plant counts were taken 4 to 6 wk after planting while ear height measurements were taken approximately four wk prior to corn harvest. Crop yield was determined by harvesting all eight rows of each plot with a combine. Weights were adjusted to 12% moisture. Experimental design was a factorial arrangement using a randomized complete block design with corn hybrid (2), row spacing (2), and seeding rates (3) as factors. Data were analyzed using PROC GLM with SAS (SAS Institute, Inc., Cary, NC) and treatment means separated by Fisher's protected least significant difference test at P = 0.05. Plant height was not affected by plant populations or row spacing as only hybrid response was significant with BH 8900 being taller in both years. Row spacing affected ear height in one of two years with the twin row spacing having a taller ear placement in the dryer year. No differences were seen with ear placement with respect to plant populations. In the dry year, yield of BH 8844 decreased as plant populations increased; however, no differences were noted with BH 8900. In the wet year, the inverse was seen with increased yield with higher populations with both hybrids. The twin row system increased BH 8900 yield in 2013. In 2014, with BH 8844, the single row system outyielded twin row and no differences noted with BH 8900. The results were quite variable and this was due in part to rainfall events in the two years. Plant and ear height was influenced by hybrid while yield response was somewhat affected by population and row spacing. A hybrid x row width response was noted indicating that certain hybrids will respond to row spacing more than others.

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Chlorophyll a Fluorescence Parameters do not Detect Yield-limiting Injury from Sub-lethal Rates of 2,4-Dichlorophenoxyacetic Acid (2,4-D) in Cotton (Gossypium hirsutum)

Journal of Experimental Agriculture International ◽

10.9734/jeai/2020/v42i130449 ◽

2020 ◽

pp. 34-48

Author(s):

Seth A. Byrd ◽

John L. Snider ◽

Timothy L. Grey ◽

A. Stanley Culpepper ◽

Jared R. Whitaker ◽

...

Keyword(s):

Chlorophyll A ◽

Chlorophyll A Fluorescence ◽

Yield Loss ◽

Block Design ◽

Dichlorophenoxyacetic Acid ◽

Growth Stages ◽

Biologically Relevant ◽

Fluorescence Parameters ◽

Significant Difference ◽

2,4 Dichlorophenoxyacetic Acid

Aims: Determine if the use of novel chlorophyll a fluorescence parameters could be utilized to predict yield loss of cotton exposed to sublethal rates of 2,4-dichlorophenoxyacetic acid (2,4-D) at various growth stages. Study Design: All trials were arranged in a randomized complete block design with four replications. Treatment means were subjected to analysis of variance and linear regression was utilized to determine relationship between chlorophyll a parameters and yield. Place and Duration of Study: University of Georgia Gibbs Farm in Tifton, GA, USA and the Sunbelt Agricultural Exposition in Moultrie, GA, USA during the 2013 growing season. Methodology: Two sublethal rates of 2,4-D were applied to cotton at six distinct growth stages. The rates consisted of 2 g and 40 g ae ha-1 equivalent to 1/421 and 1/21 of the full rate (0.532 kg ae ha-1), respectively. The sublethal rates were applied to cotton at six growth stages, including the four leaf, nine leaf, first bloom, two, four and six weeks after first bloom growth stages. A fluorometer was used to obtain the fluorescence parameters Fv/Fm, ΦEO and PIABS from the uppermost fully expanded leaves at various intervals after 2,4-D exposure. Results: Despite yield losses ranging from 20 – 90% of the non-treated control, no consistent patterns resulted from utilizing fluorescence transients to detect 2,4-D injury and overall instances of significant difference were minimal and typically not biologically relevant. In many cases, treatments exposed to 2,4-D that exhibited yield loss showed evidence of greater photosynthetic efficiency than the non-treated control. In the majority of instances, many of fluorescence parameters measured fell within ranges observed in previous studies in cotton produced under typical or non-stressed conditions. Conclusion: While it has been proven as a valuable tool in other plant screening endeavors, chlorophyll a fluorescence were not able to detect the effects of sub-lethal rates of 2,4-D on cotton, even in instances that resulted in severe yield loss.

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The Effect of Dicamba on Peanut When Applied during Vegetative Growth Stages

Peanut Science ◽

10.3146/0095-3679-42.2.109 ◽

2015 ◽

Vol 42 (2) ◽

pp. 109-120 ◽

Cited By ~ 1

Author(s):

B.H. Blanchett ◽

T.L. Grey ◽

E.P. Prostko ◽

T.M. Webster

Keyword(s):

Linear Relationship ◽

Regression Models ◽

Growth Stage ◽

Yield Loss ◽

Maximum Yield ◽

Field Studies ◽

Growth Stages ◽

Linear Regression Models ◽

Target Movement ◽

Crop Injury

ABSTRACT The development of dicamba-resistant cotton and soybean cultivars has created great concern about the potential off-target movement of dicamba onto sensitive species, including broadleaf crops. Peanut is often grown in close proximity to cotton and soybean. Therefore, field studies were conducted during 2012 and 2013 at Plains, Ty Ty, and Attapulgus, GA to evaluate peanut response to rates of dicamba (35, 70, 140, 280, and 560 g ae ha−1) applied at preemergence (PRE), 10, 20, or 30 d after planting (DAP) corresponding to PRE, V2, V3, and V5 peanut growth stages, respectively. Nontreated controls were included for comparison. As dicamba rate increased, both peanut injury and peanut yield loss increased. Peanut response to dicamba was fit to log-logistic regression models for injury and linear regression models for yield loss. Peanut injury increased with rate of dicamba, but was variable among the locations. A general trend was that peanut plants became more sensitive to dicamba injury as plants approached reproductive stage, as evidenced through a declining linear relationship between I50 values (i.e. rate of dicamba that elicits a 50% crop response) and timing of application. PRE applications of dicamba had I50 values that ranged from 125 to 323 g ha−1 of dicamba, while I50 values were 44 to 48 g ha−1 of dicamba at the V5 peanut growth stage. There was a linear relationship between peanut yield and dicamba rate, with 560 g ha−1 causing maximum yield losses ranging from 0 to 86% when applied PRE, 24 to 82% when applied at V2 growth stage, 30 to 95% when applied at V3 growth stage, and 45 to 88% when applied at V5 growth stage. Across all treatments and locations, there was also a negative linear relationship between peanut yield and peanut crop injury, with a decline of 8.5% yield for every 10% increase in crop injury. Growers and their consultants/extension agents can use this peanut injury data to predict potential peanut yield loss from sprayer contamination or off-target movement of dicamba.

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The Effect of 2,4-Dichlorophenoxyacetic Acid (2,4-D) on Peanut when Applied During Vegetative Growth Stages

Peanut Science ◽

10.3146/ps16-15.1 ◽

2017 ◽

Vol 44 (1) ◽

pp. 53-59 ◽

Cited By ~ 2

Author(s):

B.H. Blanchett ◽

T.L. Grey ◽

E.P. Prostko ◽

W.K. Vencill ◽

T.M. Webster

Keyword(s):

Growth Stage ◽

Yield Loss ◽

Correlation Coefficients ◽

Field Studies ◽

Time Frame ◽

Dichlorophenoxyacetic Acid ◽

Growth Stages ◽

Linear Regression Models ◽

Target Movement ◽

2,4 Dichlorophenoxyacetic Acid

ABSTRACT The development of 2,4-D-resistant cotton and soybean cultivars has created great concern about the potential off-target movement of 2,4-D onto sensitive broadleaf crops. Peanut is often grown in close proximity to cotton and soybean. Therefore, field studies were conducted during 2012 and 2013 at Plains, Ty Ty, and Attapulgus, GA to evaluate peanut response to 2,4-D at 67, 133, 266, 533, and 1066 g ae ha−1 applied at preemergence (PRE), 10, 20, or 30 d after planting (DAP), corresponding to PRE, V2, V3, and V5 peanut growth stages. Nontreated controls (NTC) were included for comparison. Treatment timing by rate interactions were significant (P < 0.0001). As 2,4-D rate increased peanut injury increased. There was variation in yield loss response dependent on peanut growth stage at application timing. Peanut that was treated preemergence and at the V2 growth stage did not have yield loss at any of the 2,4-D evaluated rates (67 to 1066 g ha−1) relative to the NTC. When peanut was treated at V3 and V5 growth stages with 2,4-D, injury estimates were 5 to 32% from the 67 to 1066 g ha−1 rates respectively, and peanut canopy diameter was stunted 5 to 35% at the same rates. The resulting peanut yield loss was 23 and 36% from 533 and 1066 g ha−1 of 2,4-D applied at V3 and V5 growth stages; in part due to reproductive growth being initiated during that time-frame and peanut had less time to recuperate before harvest. Linear regression models were used to evaluate peanut injury and peanut yield results. Significant correlations were established for V3 and V5 treatments between injury and yield, injury and canopy diameter, and canopy diameter and yield (P < 0.0001), with correlation coefficients of − 0.48, − 0.76, and 0.51, respectively. Growers and extension agents will be able to use these peanut injury estimates and canopy diameter data to make improved predictions of potential peanut yield loss where off-target movement of 2,4-D or sprayer contamination has occurred.

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Storage Root Yield of Sweetpotato as Influenced by Sweetpotato leaf curl virus and Its Interaction With Sweetpotato feathery mottle virus and Sweetpotato chlorotic stunt virus in Kenya

Plant Disease ◽

10.1094/pdis-06-19-1196-re ◽

2020 ◽

Vol 104 (5) ◽

pp. 1477-1486

Author(s):

Bramwel W. Wanjala ◽

Elijah M. Ateka ◽

Douglas W. Miano ◽

Jan W. Low ◽

Jan F. Kreuze

Keyword(s):

Yield Loss ◽

Virus Disease ◽

Block Design ◽

Mottle Virus ◽

Yield Response ◽

Yield Reduction ◽

Root Yield ◽

Moderately Resistant ◽

Leaf Curl Virus ◽

Leaf Curl

In this study, the effect of a Kenyan strain of Sweetpotato leaf curl virus (SPLCV) and its interactions with Sweetpotato feathery mottle virus (SPFMV) and Sweetpotato chlorotic stunt virus (SPCSV) on root yield was determined. Trials were performed during two seasons using varieties Kakamega and Ejumula and contrasting in their resistance to sweetpotato virus disease in a randomized complete block design with 16 treatments replicated three times. The treatments included plants graft inoculated with SPLCV, SPFMV, and SPCSV alone and in possible dual or triple combinations. Yield and yield-related parameters were evaluated at harvest. The results showed marked differences in the effect of SPLCV infection on the two varieties. Ejumula, which is highly susceptible to SPFMV and SPCSV, suffered no significant yield loss from SPLCV infection, whereas Kakamega, which is moderately resistant to SPFMV and SPCSV, suffered an average of 47% yield loss from SPLCV, despite only mild symptoms occurring in both varieties. These results highlight the variability in yield response to SPLCV between sweetpotato cultivars as well as a lack of correlation of SPLCV-related symptoms with yield reduction. In addition, they underline the lack of correlation between resistance to the RNA viruses SPCSV and SPFMV and the DNA virus SPLCV. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

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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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Differential Tolerance of Clearfield Rice Cultivars to Imazamox

Weed Technology ◽

10.1614/wt-d-10-00129.1 ◽

2011 ◽

Vol 25 (2) ◽

pp. 192-197 ◽

Cited By ~ 17

Author(s):

Jason A. Bond ◽

Timothy W. Walker

Keyword(s):

Growth Stage ◽

Rice Yield ◽

Field Studies ◽

First Year ◽

Growth Stages ◽

Rice Cultivars ◽

Rough Rice ◽

Rice Yields ◽

Clearfield Rice ◽

Two Hybrid

Field studies were conducted to compare the response of one inbred (‘CL161’) and two hybrid (‘CLXL729’ and ‘CLXL745’) Clearfield (CL) rice cultivars to imazamox. Imazamox was applied at 44 and 88 g ai ha−1to rice in the panicle initiation (PI) and PI plus 14 d (PI + 14) growth stages and at 44 g ha−1to rice in the midboot growth stage. Maturity of hybrid CL cultivars was delayed following imazamox at 44 g ha−1applied at PI + 14 and midboot. Furthermore, imazamox at 44 g ha−1, applied at midboot, delayed maturity of CLXL745 more than CLXL729. Expressed as a percentage of the weed-free control plots, rough rice yields for CLXL729 were 91% following imazamox at 44 g ha−1applied at PI + 14, 78% following imazamox at 44 g ha−1applied at midboot, and 77% for imazamox at 88 g ha−1applied at PI + 14. Rough rice yield for CLXL745 was 77 to 92% of the control following all imazamox treatments. All imazamox treatments reduced CLXL745 rough rice yield compared with CL161. Rough rice yield, pooled across CL cultivar, varied with imazamox treatment between years, and these differences may have been a consequence of lower temperatures and solar radiation in the first year. Hybrid CL cultivars CLXL729 and CLXL745 were less tolerant than was CL161 when imazamox was applied at nonlabeled rates (88 g ha−1) and/or timings (PI + 14 or midboot). Because of variability in rice growth stages and irregularities in imazamox application in commercial fields, inbred CL cultivars should be planted where an imazamox application will likely be required.

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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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Effect of Irrigation and Nitrogen Fertilization Strategies on Silage Corn Grown in Semi-Arid Conditions

Agronomy ◽

10.3390/agronomy8100208 ◽

2018 ◽

Vol 8 (10) ◽

pp. 208 ◽

Cited By ~ 8

Author(s):

Abdelaziz Nilahyane ◽

M. Islam ◽

Abdel Mesbah ◽

Axel Garcia y Garcia

Keyword(s):

Irrigation Water ◽

Block Design ◽

Nitrate Solution ◽

High Yield ◽

Growth Stages ◽

Growing Seasons ◽

Ammonium Nitrate Solution ◽

Significant Difference ◽

Water Scarce ◽

Semi Arid

In water-scarce regions, high yield and improved water use efficiency (WUE) of crops can be obtained if water and nitrogen (N) are properly applied. While water and N have been the subject of research worldwide, studies are needed to advance our understanding on the complexity of their interaction. A field experiment was conducted at the University of Wyoming Powell Research and Extension Center in 2014 and 2015 growing seasons to determine the effect of irrigation water and N on growth, dry matter (DM) yield, and WUE of silage corn (Zea mays L.) grown under on-surface drip irrigation (ODI). The experiment was laid out as a randomized complete block design in split-plot arrangement with three replications. Irrigation was the main treatment and included 100ETc (100% crop evapotranspiration), 80ETc, and 60ETc. Nitrogen was the sub-treatment and included 0, 90, 180, 270, and 360 kg N ha−1 as urea-ammonium-nitrate solution Results showed that irrigation water, N, and application timing significantly affected growth and DM yield, especially at late vegetative and mid reproductive growth stages. At harvest (R4), no significant difference was observed between 180 kg N ha−1 and 270 kg N ha−1 on DM yield and WUE. However, significant differences of DM yield were observed between irrigation treatments, and 100ETc and 80ETc did not differ in WUE. Our findings suggest that 100ETc and 180 kg N ha−1 is the best combination for high yielding corn for silage grown in a semi-arid climate under ODI.

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Comparison of allelopathic effects of some brassica species in two growth stages on germination and growth of sunflower

Plant Soil and Environment ◽

10.17221/139/2010-pse ◽

2011 ◽

Vol 57 (No. 2) ◽

pp. 52-56 ◽

Cited By ~ 11

Author(s):

E. Jafariehyazdi ◽

F. Javidfar

Keyword(s):

Germination Rate ◽

Growth Stages ◽

Distilled Water ◽

Aqueous Extracts ◽

Hypocotyl Length ◽

Allelopathic Potential ◽

Brassica Spp ◽

Full Flowering ◽

Significant Difference ◽

Two Stages

Members of Brassicaceae have been frequently cited as allelopathic crop. The toxic effect of Brassica spp. may be caused by hydrolysis products of glucosinolates that occur in substantial amounts in the vegetative parts of Brassica spp. This study investigated the allelopathic potential of Brassica napus, B. rapa and B. juncea on the sunflower seed germination and seedling growth. Aqueous extracts of three species from two stages (full flowering and straw) of sampling were separately made with 0 (distilled water), 10, 20, 30 and 40% concentrations. This experiment was conducted in 2 × 3 × 5 factorial arrangement based on completely randomized design with five replications. There was a highly significant difference among different concentrations of extracts and also between two stages of extraction. All aqueous extracts significantly affected sunflower germination, germination rate, seedling root and hypocotyl length, fresh and dry matter weight when compared with distilled water control. The greatest concentration showed a stronger inhibitory effect. Root length was more sensitive to extracts than hypocotyl length.

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