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.

scholarly journals Biological Control of the Weedy Plant (Rumex crispus) at the Seedling Growth Stage by the Green Dock Beetle (Gastrophysa viridula)

2019 ◽  
Vol 28 (1) ◽  
pp. 21-31
Author(s):  
Khalid S. Alshallash Khalid S. Alshallash
Keyword(s):  
Biological Control ◽  
Seedling Growth ◽  
Growth Stage ◽  
Biological Control Agent ◽  
Dry Weight ◽  
Control Agent ◽  
Growth Stages ◽  
Rumex Crispus ◽  
Shoot Number ◽  
The Impact

In four glasshouse experiments, the effectiveness of the adult green dock beetle Gastrophysa viridula (Coleoptera: Chrysomelidae), at the effective number of applied individuals, for use as a biological control agent of curled dock, Rumex crispus (Polygonaceae) were studied. The feeding of the beetle was investigated at four different numbers of beetle (0, 1, 2, 3) and at four seedling growth stages of the plant, defined by the average of leaf area per plant (1-1.22 , 2-4.45, 3-11.56, and 4-71.52 cm2/plant). Grazing by one, two or three dock beetles did not result in a significant reduction in dock dry weight or shoot numbers at the youngest growth stage. However, both at later seedling growth stages were significantly affected (P ? 0.0001), at any beetles number. The increase of beetle numbers caused nonsignificant increased effect, in some trials, confirming the impact of a single beetle. Three months after beetle grazing, dock seedlings of first, second and third growth stages were not able to regrow, however, some plants at the 4th growth stage, re-emerged. This suggested that the highest effect of beetle's feeding occurs on the early seedling stages. Statistical analysis showed a positive correlation (0.77) between dry weight and shoot number at all the four seedling growth stages, thus confirming the impact of the beetle on both the dry weight and shoot numbers. Combining beetle grazing with other control methods at older dock seedling stages could, therefore, provide better suppression

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.

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.

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.

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.

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.

EVALUATION OF VELVETLEAF INTERFERENCE WITH MAIZE HYBRIDS AS INFLUENCED BY RELATIVE TIME OF EMERGENCE

2011 ◽  
Vol 48 (1) ◽  
pp. 127-137 ◽  
Author(s):  
ILIAS S. TRAVLOS ◽  
PANAGIOTIS J. KANATAS ◽  
GARIFALIA ECONOMOU ◽  
VASILIS E. KOTOULAS ◽  
DIMOSTHENIS CHACHALIS ◽  
...  
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Yield Loss ◽  
Integrated Weed Management ◽  
Growth Stages ◽  
Arid Environments ◽  
Initial Growth ◽  
Maize Hybrids ◽  
Canopy Area ◽  
Semi Arid

SUMMARYThe presence of velvetleaf (Abutilon theophrasti) in crops is increasing in arid and semi-arid environments. Field experiments were conducted in Greece in 2009 and 2010 to determine the influence of velvetleaf emergence time and maize (Zea mays) hybrids with different growth rates on maize yield and velvetleaf growth and fecundity. Velvetleaf was uniformly seeded in order to emerge at the 1, 3, 5 and 7-leaf stage of maize (V1, V3, V5 and V7 growth stages, respectively). Velvetleaf biomass, canopy area and seed production were significantly affected by the date of velvetleaf emergence. Velvetleaf plants emerging just after maize (V1) produced 7–17 times lower seed number, compared with the V5 growth stage. Maximum maize grain yield loss ranged from 26 to 37% for early emerging velvetleaf, and less than 6% yield loss occurred from velvetleaf seedlings emerging at V7 growth stage. Maize hybrids with high initial growth rate seem to be more competitive than the other hybrids. The results of this study are essential in the development of an integrated weed management strategy for maize in semi-arid environments, since they highlight the importance of the careful selection of a competitive maize hybrid and avoidance of early velvetleaf emergence.

scholarly journals Seasonal Progression, Symptom Development, and Yield Effects of Alfalfa mosaic virus Epidemics on Soybean in Wisconsin

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 266-272 ◽  
Author(s):  
Emily E. Mueller ◽  
Craig R. Grau
Keyword(s):  
Mosaic Virus ◽  
Growth Stage ◽  
Yield Loss ◽  
Seed Quality ◽  
Alfalfa Mosaic Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Growth Stages ◽  
Seasonal Incidence ◽  
Soybean Yield ◽  
Foliar Symptoms

The occurrence of Alfalfa mosaic virus (AMV) has increased in Wisconsin soybean fields in conjunction with the establishment of the soybean aphid (Aphis glycines). Field studies were conducted to determine the seasonal incidence of AMV-infected plants, progression of symptom severity caused by AMV, and the effect of AMV on soybean yield and seed quality. An isolate of AMV, collected from field-grown soybean, was introduced into plots by mechanical inoculation of plants at the V1 growth stage. The goal of the experiment was to achieve an incidence of AMV-infected plants of 0, 50, and 100% in 2002, and 0, 10, 25, 50, 75, and 100% in 2003. Severity of foliar symptoms was rated, and leaf samples were collected for serological assay (enzyme-linked immunosorbent assay [ELISA]) to estimate the incidence of AMV-infected plants from growth stages VC to R5. The maximum incidence of AMV-infected plants was 49% at growth stage R5, yet detection of the virus by ELISA dropped dramatically thereafter in both years. Incidence of AMV-infected plants accounted for 53 to 67% of the variability observed for severity of foliar symptoms in 2002 and 2003, respectively. Maximum yield loss ranged from 32% in 2002 to 48% in 2003 based on the difference in yield between noninoculated plots and plots with the highest incidence of AMV-infected plants. Incidence of AMV-infected plants explained 31% of the variation in yield in 2002 and 26% in 2003. An AMV incidence of 30% or greater was required for yield loss caused by AMV. Results of this study suggest that AMV has the potential to lower soybean yield and warrants further study.

Soybean Sensitivity to Drift Rates of Imazosulfuron

2014 ◽  
Vol 28 (3) ◽  
pp. 443-453 ◽  
Author(s):  
Sandeep S. Rana ◽  
Jason K. Norsworthy ◽  
Robert C. Scott
Keyword(s):  
Growth Stage ◽  
Yield Loss ◽  
Field Trials ◽  
Application Rate ◽  
Early Growth ◽  
Growth Stages ◽  
Sulfonylurea Herbicide ◽  
Full Bloom ◽  
Close Proximity ◽  
Different Growth Stages

Imazosulfuron is a sulfonylurea herbicide recently labeled in U.S. rice at a maximum rate of 336 g ai ha−1. Soybean is prone to drift of herbicides from rice fields in the southern United States because these crops are often grown in close proximity. Field trials were conducted to determine the effect of low rates of imazosulfuron applied to nonsulfonylurea-resistant soybean at different growth stages. Soybean was treated at the vegetative cotyledonary (VC); vegetative second trifoliate (V2); vegetative sixth trifoliate (V6); and reproductive full bloom (R2) growth stages with 1/256 (1.3 g ha−1) to 1/4 (84.1 g ha−1) times (X) the maximum labeled rate of imazosulfuron. Soybean was injured regardless of application rate or timing. At 2 wk after treatment (WAT), imazosulfuron injured soybean 23 to 79, 44 to 76, 32 to 68, and 14 to 50% when applied at the VC, V2, V6, and R2 growth stages, respectively, where the highest injury was caused by the highest imazosulfuron rate (1/4X). However, by 20 wk after planting (WAP), soybean treated with imazosulfuron at the VC and V2 growth stages had only 0 to 17% and 8 to 53% injury, respectively. At higher rates [1/8 (42 g ha−1) and 1/4X] of imazosulfuron, soybean treated at the VC growth stage recovered more from injury than did soybean treated at the V2 growth stage. Soybean treated with imazosulfuron at the V6 and R2 growth stages had better recovery from the injury at the lower two rates [1/256 and 1/128X (2.6 g ha−1)] than at the higher rates [1/64 (5.3 g ha−1) to 1/4X]. Imazosulfuron, at all rates tested, delayed soybean maturity by 1 to 4, 2 to 6, 1 to 12, and 3 to 16 d for the VC, V2, V6, and R2 growth stages, respectively. Yield loss was greater when imazosulfuron was applied at V6 and R2 compared to applications at VC and V2. Results from this research indicate that imazosulfuron can severely injure soybean regardless of the growth stage at which drift occurs; however, soybean injured by imazosulfuron at early growth stages (VC and V2) has a better chance of recovery over time compared to drift at later growth stages (V6 and R2).

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