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

2019 ◽  
Vol 33 (2) ◽  
pp. 321-328 ◽  
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.

Effect of Growth Stage on Cotton Response to a Sublethal Concentration of Dicamba

2018 ◽  
Vol 33 (1) ◽  
pp. 1-8 ◽  
Author(s):  
John T. Buol ◽  
Daniel B. Reynolds ◽  
Darrin M. Dodds ◽  
J. Anthony Mills ◽  
Robert L. Nichols ◽  
...  
Keyword(s):  
Control Systems ◽  
Fiber Length ◽  
Field Experiments ◽  
Fiber Quality ◽  
Sublethal Concentration ◽  
Growth Stages ◽  
Seed Cotton ◽  
Visible Injury ◽  
Crop Maturity ◽  
Sublethal Concentrations

AbstractThe introduction of auxin herbicide weed control systems has led to increased occurrence of crop injury in susceptible soybeans and cotton. Off-target exposure to sublethal concentrations of dicamba can occur at varying growth stages, which may affect crop response. Field experiments were conducted in Mississippi in 2014, 2015, and 2016 to characterize cotton response to a sublethal concentration of dicamba equivalent to 1/16X the labeled rate. Weekly applications of dicamba at 35 g ae ha−1were made to separate sets of replicated plots immediately following planting until 14 wk after emergence (WAE). Exposure to dicamba from 1 to 9 WAE resulted in up to 32% visible injury, and exposure from 7 to 10 WAE delayed crop maturity. Exposure from 8 to 10 and 13 WAE led to increased cotton height, while an 18% reduction in machine-harvested yield resulted from exposure at 6 WAE. Cotton exposure at 3 to 9 WAE reduced the seed cotton weight partitioned to position 1 fruiting sites, while exposure at 3 to 6 WAE also reduced yield in position 2 fruiting sites. Exposure at 2, 3, and 5 to 7 WAE increased the percent of yield partitioned to vegetative branches. An increase in percent of yield partitioned to plants with aborted terminals occurred following exposure from 3 to 7 WAE and corresponded with reciprocal decreases in yield partitioned to positional fruiting sites. Minimal effects were observed on fiber quality, except for decreases in fiber length uniformity resulting from exposure at 9 and 10 WAE.

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

2019 ◽  
Vol 33 (04) ◽  
pp. 555-561 ◽  
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.

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

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.

scholarly journals Rhizopus Head Rot of Confectionery Sunflower: Effects on Yield Quantity and Quality and Implications for Disease Management

1997 ◽  
Vol 87 (12) ◽  
pp. 1226-1232 ◽  
Author(s):  
D. Shtienberg
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Rhizopus Oryzae ◽  
Development Stage ◽  
Crop Growth ◽  
Growth Stages ◽  
Yield Quality ◽  
Crop Growth Stage ◽  
Head Rot ◽  
The Individual

The effects of Rhizopus head rot, caused by Rhizopus oryzae, on the yield of confectionery sunflower and its quality were studied in field experiments conducted from 1994 to 1996. The extent of yield loss was related to the crop growth stage at inoculation. When heads were inoculated at the budding stage, loss was not apparent, because inoculated heads were not infected. When inoculated at the anthesis stage, loss was relatively high (42.5 to 99.1%), and both the number of achenes per head and the individual achene weight were reduced. When heads were inoculated at the seed development stage, yield was not reduced significantly (although the entire receptacle was rotted). Effects of Rhizopus head rot on measures of yield quality were examined as well. Inoculation with R. oryzae did not affect the size of the achenes at any crop growth stage. In contrast, the incidence of discolored achenes (an external sign of nutmeats with a bitter off-flavor) was affected by the disease at all crop growth stages. A survey in eight commercial fields from 1992 to 1996 found that, by the end of the season, incidence of disease ranged from 2.3 to 17.4%. However, since disease intensified late, resultant yield losses were minor and did not exceed 3.1%. Loss figures were estimated by means of a model that was developed and validated in the field experiments. The disease did affect the incidence of discolored achenes. Thus, the conclusion drawn is that the effects of Rhizopus head rot in confectionery sunflower on crop yield is of minimal concern, at least when disease intensifies late, as was the case in the studied fields, but management of the disease should be considered in some situations. The objectives would be to prevent a reduction in yield quality, not yield quantity.

A review of copper fertilizer management for optimum yield and quality of crops in the Canadian Prairie provinces

2006 ◽  
Vol 86 (3) ◽  
pp. 605-619 ◽  
Author(s):  
S. S. Malhi ◽  
R. E. Karamanos
Keyword(s):  
Seed Yield ◽  
Growth Stage ◽  
Field Experiments ◽  
Seed Quality ◽  
Soil Analysis ◽  
Growth Stages ◽  
Canadian Prairie ◽  
Cu Deficiency ◽  
Yield And Quality

Deficiency of copper (Cu) in Canadian prairie soils is not widespread, but whenever it occurs it can cause a drastic reduction in seed yield and quality of most cereals, especially wheat. Field experiments conducted in western Canada indicated that broadcast-incorporation of granular Cu fertilizers prior to seeding at 3-5.6 kg Cu ha-1 was usually sufficient to prevent Cu deficiency in wheat, and improve seed yield and quality. At lower rates (< 2.0 kg Cu ha-1), broadcast-incorporation of granular Cu fertilizers was not effective, while surface spray-broadcast followed by incorporation of liquid Cu fertilizers was much more effective in increasing seed yield of wheat in the first year of application. Surface broadcast without incorporation and seedrow-placed granular Cu fertilizers were much less effective in improving seed yield of wheat than their foliar or soil-incorporated applications. In the growing season, foliar applications of Cu at 0.20 to 0.28 kg Cu ha-1 to wheat at the Feekes 6 (first node of stem visible at base of shoot or stem elongation), Feekes 10 (sheath of last leaf completely grown or flag-leaf) and early boot growth stages were very effective in restoring seed yield, while Cu applications at the Feekes 2 (four-leaf) or Feekes 10.5 (complete heading) growth stage did not have a consistent effect to correct damage caused by Cu deficiency. Some Cu fertilizers (e.g., Cu oxide) were less effective than others in preventing/correcting Cu deficiency. Soil application at relatively high rates produced residual benefits in increasing seed yield for a number of years. The sensitivity of crops to Cu deficiency is usually in the order (wheat, flax, canary seed) > (barley, alfalfa) > (timothy seed, oats, corn) > (peas, clovers) > (canola, rye, forage grasses). Stem melanosis in wheat was associated with deficiency of Cu in soil, and the disease was reduced substantially with Cu application. A high level of available P in soil was observed to induce/increase severity of Cu deficiency in wheat. Soil analysis for diethylene triamine pentacetic acid- (DTPA) extractable Cu in soil can be used as a good diagnostic tool to predict Cu deficiency, but there was a poor relationship between total Cu concentration in shoots and the degree of Cu deficiency in crops. Application of Cu fertilizers to wheat on Cu-deficient soils also generally improved seed quality. Key words: Application time, Cu source, foliar application, granular Cu, growth stage, placement method, rate of Cu, seedrow-placed Cu, soil incorporation, wheat

Cotton (Gossypium Hirsutum) Response to DPX-PE350 Applied Postemergence

1993 ◽  
Vol 7 (1) ◽  
pp. 159-162 ◽  
Author(s):  
David L. Jordan ◽  
Robert E. Frans ◽  
Marilyn R. McClelland
Keyword(s):  
Adverse Effect ◽  
Gossypium Hirsutum ◽  
Fiber Length ◽  
Field Experiments ◽  
Fiber Strength ◽  
Fiber Quality ◽  
Growth Stages ◽  
Cotton Yield ◽  
Seed Cotton ◽  
Over The Top

Field experiments were conducted from 1989 through 1991 to determine the effect of DPX-PE350 applied postemergence over-the-top on cotton yield and fiber quality. DPX-PE350, at rates ranging from 50 to 280 g ae ha−1applied to cotton in the VC to R6 growth stages, had no adverse effect on seed cotton yield, micronaire, fiber length, fiber length uniformity, or fiber strength. Cotton injury was 10% or less in all experiments.

scholarly journals Growth-Dependent Stable Carbon Isotope Fractionation by Basidiomycete Fungi: δ13C Pattern and Physiological Process

2002 ◽  
Vol 68 (10) ◽  
pp. 4956-4964 ◽  
Author(s):  
Matthew R. Henn ◽  
Gerd Gleixner ◽  
Ignacio H. Chapela
Keyword(s):  
Growth Medium ◽  
Fungal Biomass ◽  
Growth Stage ◽  
Stable Carbon Isotope ◽  
Axenic Culture ◽  
Growth Stages ◽  
Second Phase ◽  
C Isotopes ◽  
Low Concentrations ◽  
The Impact

ABSTRACT We grew 11 basidiomycetes in axenic culture to characterize their physiological capacities to fractionate stable C isotopes. Generally, δ13C values of the fungal biomass were (i) enriched in 13C relative to the growth medium, (ii) variable among the isolates, and (iii) dependent on the growth rate and growth stage of the fungi. We found a multiphasic dynamic of fractionation for Cryptoporus volvatus and Marasmius androsaceus during various growth stages. The first phase, P1, corresponded to the exponential growth stage and was characterized by an increasing enrichment in 13C content of the fungal biomass relative to the growth medium ranging between 4.6 and 6.9‰. The second phase, P2, exhibited a continual depletion in 13C of the fungal biomass, with the δ13C values of the fungal biomass asymptotically returning to the δ13C value of the growth medium at inoculation. The expression of the various fractionation phases was dependent on the amount of low-concentration micronutrients and growth factors added to the growth medium. The onset of P2 occurred at reduced concentrations of these elements. All of the sugars in the growth medium (sucrose, maltose, and glucose) were utilized for growth, indicating that the observed fractionation was not an artifact derived from the preferential use of 13C-rich maltose, which was found at low concentrations in the growth medium. In this study, we establish a framework with which to explore the impact of physiological fractionations by fungal interfaces on natural distributions of stable C isotopes.

Growth Stage-Influenced Differential Response of Foxtail and Pigweed Species to Broadcast Flaming

2010 ◽  
Vol 24 (3) ◽  
pp. 319-325 ◽  
Author(s):  
Santiago M. Ulloa ◽  
Avishek Datta ◽  
Stevan Z. Knezevic
Keyword(s):  
Weed Control ◽  
Dry Matter ◽  
Growth Stage ◽  
Field Experiments ◽  
Growth Stages ◽  
Weed Species ◽  
Common Waterhemp ◽  
Species Response ◽  
Redroot Pigweed ◽  
Green Foxtail

Propane flaming could be an effective alternative tool for weed control in organic cropping systems. However, response of major weeds to broadcast flaming must be determined to optimize its proper use. Therefore, field experiments were conducted at the Haskell Agricultural Laboratory, Concord, NE in 2007 and 2008 using six propane doses and four weed species, including green foxtail, yellow foxtail, redroot pigweed, and common waterhemp. Our objective was to describe dose–response curves for weed control with propane. Propane flaming response was evaluated at three different growth stages for each weed species. The propane doses were 0, 12, 31, 50, 68, and 87 kg ha−1. Flaming treatments were applied utilizing a custom-built flamer mounted on a four-wheeler (all-terrain vehicle) moving at a constant speed of 6.4 km h−1. The response of the weed species to propane flaming was evaluated in terms of visual ratings of weed control and dry matter recorded at 14 d after treatment. Weed species response to propane doses were described by log-logistic models relating propane dose to visual ratings or plant dry matter. Overall, response of the weed species to propane flaming varied among species, growth stages, and propane dose. In general, foxtail species were more tolerant than pigweed species. For example, about 85 and 86 kg ha−1were the calculated doses needed for 90% dry matter reduction in five-leaf green foxtail and four-leaf yellow foxtail compared with significantly lower doses of 68 and 46 kg ha−1of propane for five-leaf redroot pigweed and common waterhemp, respectively. About 90% dry matter reduction in pigweed species was achieved with propane dose ranging from 40 to 80 kg ha−1, depending on the growth stage when flaming was conducted. A similar dose of 40 to 60 kg ha−1provided 80% reduction in dry matter for both foxtail species when flaming was done at their vegetative growth stage. However, none of the doses we tested could provide 90% dry matter reduction in foxtail species at flowering stage. It is important to note that foxtail species started regrowing 2 to 3 wk after flaming. Broadcast flaming has potential for control or suppression of weeds in organic farming.

Response of Chickpea Cultivars to Imidazolinone Herbicide Applied at Different Growth Stages

2016 ◽  
Vol 30 (3) ◽  
pp. 664-676 ◽  
Author(s):  
M. Laura Jefferies ◽  
Christian J. Willenborg ◽  
Bunyamin Tar'an
Keyword(s):  
Great Plains ◽  
Growth Stage ◽  
Field Experiments ◽  
Northern Great Plains ◽  
Yield Reduction ◽  
Growth Stages ◽  
Resistant Cultivars ◽  
Node Development ◽  
Different Growth Stages ◽  
Chickpea Cultivars

POST broadleaf weed control options in chickpea are very limited on the Northern Great Plains. Field experiments were conducted in 2012 and 2013 in Saskatchewan to evaluate the response of chickpea cultivars to imidazolinone (IMI) herbicides applied at different growth stages. Conventional cultivars ‘CDC Luna’ and ‘CDC Corinne’ were compared with IMI-resistant cultivars ‘CDC Alma’ and ‘CDC Cory’. Treatments comprised a combination of imazethapyr + imazamox herbicides at 30 and 60 g ai ha−1(1× and 2× rates, respectively) applied at the 2 to 4-, 5 to 8-, and 9 to 12-node growth stages. Visual injury estimates were > 50% for CDC Luna and CDC Corinne for all growth stage applications. Conventional cultivars also experienced height reduction and decreased rate of node development compared with the nontreated controls. Flowering and maturity of CDC Luna and CDC Corinne were delayed for herbicide applications at all growth stages; however, application at the 9 to 12-node stage caused the most severe delay. All treatments of IMI herbicide caused yield reduction in the conventional cultivars in 2013. In contrast, IMI-resistant cultivars CDC Alma and CDC Cory demonstrated no negative response at any growth stage of IMI herbicide application. Visual injury estimates were negligible, and height, node development, days to flowering, maturity, and yield did not differ significantly between IMI-treated plants and the respective controls. These results demonstrated the potential of in-crop use of IMI herbicide on resistant chickpea cultivars to control broadleaf weeds.

Evaluating the double knockdown technique: sequence, application interval, and annual ryegrass growth stage

2007 ◽  
Vol 58 (3) ◽  
pp. 265 ◽  
Author(s):  
Catherine P. Borger ◽  
Abul Hashem
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Growth Stages ◽  
Annual Ryegrass ◽  
Application Time ◽  
Lolium Rigidum ◽  
Single Application ◽  
Herbicide Application ◽  
Leaf Stage ◽  
The Difference

Applying glyphosate followed by a mixture of paraquat + diquat in the same season for pre-planting weed control may reduce the risk of developing resistance to either herbicide. Glasshouse and field experiments at Merredin and Beverly, Western Australia, were conducted over 2 seasons to determine the best herbicide application sequence, growth stage of annual ryegrass at which to apply the 2 herbicides, and application time and interval to be allowed between applications for optimum control of annual ryegrass (Lolium rigidum Gaud.). Annual ryegrass plants were treated at 3 growth stages with either glyphosate 540 g a.i./ha alone, paraquat + diquat 250 g a.i./ha alone, glyphosate followed by paraquat + diquat 250 g a.i./ha, or paraquat + diquat 250 g a.i./ha followed by glyphosate 540 g a.i./ha (the double knockdown treatment). The herbicides were applied at different times of the day, with varied intervals between herbicides when applied in sequence. The glasshouse experiment showed that herbicides in sequence more effectively killed annual ryegrass plants at the 3–6-leaf stage than a single application of either herbicide. Field experiments showed that applying glyphosate followed by paraquat + diquat provided 98–100% control of annual ryegrass plants when applied at the 3- or 6-leaf stage in 2002 and at all 3 growth stages in 2003. Generally, the sequence of paraquat + diquat followed by glyphosate was less effective than the reverse sequence, although the difference was not large. Averaged over 2 seasons, herbicides in sequence were most effective when the first herbicide was applied at the 3- or 6-leaf stage of annual ryegrass. An interval of 2–10 days between applications of herbicides was more effective than 1 day or less. The application time did not significantly affect the efficacy of double knockdown herbicides on annual ryegrass plants under field conditions.

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