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

Plant Disease ◽  
2010 ◽  
Vol 94 (7) ◽  
pp. 820-826 ◽  
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.

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

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.

scholarly journals Response of grain sorghum to low rates of glufosinate and nicosulfuron

2020 ◽  
pp. 1-5
Author(s):  
Hunter D. Bowman ◽  
Tom Barber ◽  
Jason K. Norsworthy ◽  
Trenton L. Roberts ◽  
Jason Kelley ◽  
...  
Keyword(s):  
Growth Stage ◽  
Yield Loss ◽  
Field Tests ◽  
Grain Sorghum ◽  
Yield Reduction ◽  
Growth Stages ◽  
Yield Losses ◽  
Visible Injury ◽  
Proportional Rate ◽  
Factor C

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.

scholarly journals Effect of Foliar Fungicide and Insecticide on Hail-Damaged Soybean

2016 ◽  
Vol 17 (2) ◽  
pp. 141-148
Author(s):  
Adam J. Sisson ◽  
Yuba R. Kandel ◽  
Chad E. Hart ◽  
Amy Asmus ◽  
Stith N. Wiggs ◽  
...  
Keyword(s):  
Disease Severity ◽  
Growth Stage ◽  
Yield Loss ◽  
Brown Spot ◽  
Growth Stages ◽  
Economic Return ◽  
Foliar Disease ◽  
Hail Damage ◽  
Seed Moisture ◽  
Foliar Fungicide

A fungicide (pyraclostrobin) and an insecticide (alpha-cypermethrin) were applied alone or in combination to hail-injured soybean to determine if yield could be preserved or foliar disease prevented. Pesticides were applied at approximately R3 growth stage and hail injury was simulated with an ice-propelling machine at approximately R1 and R4 growth stages over three years at three Iowa locations. Disease severity was low throughout the study, and included Septoria brown spot, downy mildew, and Cercospora leaf blight. Differences in disease severity among treatments receiving hail and those that did not receive hail were not consistently detected. More importantly, foliar disease severity did not differ among pesticide treatments and untreated controls. Simulated hail caused significant (P = 0.1) yield loss. No difference in yield was observed between untreated and pesticide-treated plots within hail events, except for two site years when hail damage occurred at R1. Seed moisture was generally higher in plots with R1 hail damage. Fungicide and insecticide applied in combination to hail-damaged soybean was more likely to result in a positive economic return than either applied alone. Based on results, R3 fungicide application to soybean injured by hail at R1 or R4 will likely provide little yield-preserving or disease-limiting benefits when foliar disease severity is low. Accepted for publication 21 April 2016. Published 20 June 2016.

scholarly journals Corn Yield Loss Due to Volunteer Soybean

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 495-500 ◽  
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.

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.

Effects of Low-Dose Flumioxazin and Metribuzin Postemergence Applications on Soybean

2018 ◽  
Vol 33 (1) ◽  
pp. 87-94
Author(s):  
Daniel O. Stephenson ◽  
Todd A. Spivey ◽  
Michael A. Deliberto ◽  
David C. Blouin ◽  
Brandi C. Woolam ◽  
...  
Keyword(s):  
Growth Stage ◽  
Low Dose ◽  
Yield Loss ◽  
Economic Loss ◽  
Growth Stages ◽  
Post Injury ◽  
Width Reduction ◽  
The Impact

AbstractAll herbicides will move off-target to sensitive crops when not applied correctly. Therefore, low-dose applications of flumioxazin and metribuzin were evaluated in soybean at the unifoliate, V2, and V4 growth stages. Rates evaluated were 12.5%, 25%, and 50% of the labeled use rates of 72 and 316 g ai ha−1 of flumioxazin and metribuzin, respectively. Flumioxazin injury was characterized by necrosis and visible height and width reduction. Injury increased with rate 3 d after treatment (DAT), with unifoliate, V2, and V4 soybean injured 15% to 30%, 18% to 27%, and 5% to 8%, respectively. Unifoliate and V4 soybean were injured more than V4 soybean 3 to 14 DAT, but injury decreased to <5% by 42 DAT. Soybean yields in the flumioxazin study were 92% to 96% of the nontreated, resulting in a yield loss of 196 to 393 kg ha−1 and a revenue loss of 71 to 141 US$ ha−1. Metribuzin injury was primarily chlorosis with necrosis and a visible reduction in soybean height and width. Soybean at the V2 growth stage was injured 14% more than V4 soybean 3 DAT, regardless of metribuzin rate. Injury to V2 and V4 soybean was similar 14 DAT, with injury of 21% to 40% across rates. Soybean injury when treated at the V2 and V4 growth stages was 6% to 29% 42 DAT compared to unifoliate soybean at 0 to 17%. Soybean yields in the metribuzin study yields were 96% to 98% of the nontreated. However, a 2% to 4% reduction equates to a loss of 90 to 180 kg ha−1 and a revenue loss of 32 to 65 US$ ha−1. Unifoliate and V2 soybean are more sensitive to a low dose of flumioxazin POST, and V2 and V4 soybean are more sensitive to a low dose of metribuzin POST. Injury and the impact on soybean growth could potentially cause economic loss for a soybean producer.

Irrigation of field peas (Pisum sativum): response to timing at different crop growth stages

1999 ◽  
Vol 132 (4) ◽  
pp. 417-424 ◽  
Author(s):  
C. M. KNOTT
Keyword(s):  
Pisum Sativum ◽  
Vegetative Growth ◽  
Growth Stage ◽  
Crop Growth ◽  
Yield Response ◽  
Growth Stages ◽  
Field Peas ◽  
Crop Growth Stages ◽  
Different Growth Stages

The response of two cultivars of dry harvest field peas (Pisum sativum), Solara and Bohatyr, to irrigation at different growth stages was studied on light soils overlying sand in Nottinghamshire, England in 1990, when the spring was particularly dry, in 1991 which had a dry spring and summer and in contrast, 1992, when rainfall was greater compared with the long-term (40 year) mean.Solara, short haulmed and semi-leafless was more sensitive to drought than the tall conventional-leaved cultivar Bohatyr and gave a greater yield response to irrigation, particularly at the vegetative growth stage in the first two dry years 1990 and 1991, of 108% and 55% respectively, compared with unirrigated plots. Bohatyr was less sensitive to the timing of single applications.In all years, peas irrigated throughout on several occasions produced the highest yields, but this was the least efficient use of water.

Effects of Plant Growth Stage on Glyphosate Absorption and Transport in Ligustrum (Ligustrum japonicum) and Blue Pacific Juniper (Juniperus conferta)

Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 115-121 ◽  
Author(s):  
Joseph C. Neal ◽  
Walter A. Skroch ◽  
Thomas J. Monaco
Keyword(s):  
Growth Stage ◽  
Shoot Elongation ◽  
Growth Stages ◽  
First Flush ◽  
Winter Dormancy ◽  
Differential Absorption ◽  
Seasonal Differences ◽  
Carbon 14 ◽  
Ligustrum Japonicum

Carbon-14-labeled glyphosate [N-(phosphonomethyl)glycine] was foliarly applied to ligustrum (Ligustrum japonicumThunb.) and blue pacific juniper (Juniperus confertaParl. ‘Blue Pacific’) at the following growth stages: cold acclimation, winter dormancy, budbreak, shoot elongation, and termination of the first flush of growth (shoot termination). At shoot elongation juniper plants absorbed 2% of applied14C by 14 days after treatment (DAT). Applications at other growth stages resulted in no significant absorption of14C by junipers. Within 7 DAT the amounts of radioactivity absorbed by ligustrum were significant and depended upon growth stage in the following order: budbreak < shoot termination < shoot elongation. Absorption by overwintered leaves occurred at budbreak but not at elongation or termination. Transport of absorbed14C in ligustrum was primarily acropetal and occurred only in budbreak and flowering treatments. Differences in tolerance to glyphosate between juniper and ligustrum appear to be related to differential absorption. Seasonal differences in ligustrum tolerance also appear to be associated with differences in absorption. Although growth stage affected transport in ligustrum, differential transport does not appear to play a major role in seasonal influences on long-term glyphosate phytotoxicity.

Safening Influence of LAB 145 138 on Nicosulfuron, Terbufos and Bentazon Interactions in Sweet Corn (Zea mays)

Weed Science ◽  
1996 ◽  
Vol 44 (2) ◽  
pp. 339-344 ◽  
Author(s):  
Darren K. Robinson ◽  
David W. Monks ◽  
James D. Burton
Keyword(s):  
Zea Mays ◽  
Seed Treatment ◽  
Growth Stage ◽  
Yield Loss ◽  
Sweet Corn ◽  
Leaf Growth ◽  
Growth Stages ◽  
Height Reduction ◽  
Reduced Height ◽  
Previously Treated

LAB 145 138 (LAB) was evaluated as a safener to improve sweet corn tolerance to nicosulfuron applied POST alone or with terbufos applied in the planting furrow or bentazon applied POST. To ensure enhanced injury for experimental purposes, nicosulfuron was applied at twice the registered rate alone or mixed with bentazon at the six- to seven-leaf growth stage of corn previously treated with the highest labeled rate of terbufos 15 G formulation. LAB applied as a seed treatment (ST) or POST at the two- to three-, four- to five-, or six- to seven-leaf growth stages reduced height reduction and yield loss from nicosulfuron applied POST in combination with terbufos applied in-furrow. LAB applied POST at the four- to five-leaf growth stage was most effective in preventing injury from this treatment, with yield reduced only 8% compared with 54% from the nicosulfuron and terbufos treatment. LAB applied POST at the eight- to nine-leaf growth stage did not alleviate injury. With the nicosulfuron, terbufos, and bentazon combination, LAB applied POST at the three- to four- or six- to seven-leaf growth stages decreased height reduction and yield loss caused by this combination, with LAB at the three- to four-leaf growth stage being most effective.

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