Critical Periods of Weed Control for Naked Crabgrass (Digitaria nuda), a Grass Weed in Corn in South Africa

Weed Science ◽

10.1614/ws-d-13-00152.1 ◽

2014 ◽

Vol 62 (4) ◽

pp. 647-656 ◽

Author(s):

Elbé Hugo ◽

Liesl Morey ◽

Anna E. J. Saayman-Du Toit ◽

Carl F. Reinhardt

Keyword(s):

South Africa ◽

Weed Control ◽

Relative Yield ◽

Growth Stages ◽

Yield Losses ◽

Critical Periods ◽

Planting Dates ◽

Large Crabgrass

Difficulties in chemically controlling large crabgrass in corn in South Africa have recently been attributed to the occurrence of naked crabgrass. In contrast to large crabgrass, naked crabgrass is not easily controlled with acetanilide herbicides. Critical periods of weed control (CPWC) for naked crabgrass in corn was determined in field studies during the 2009/2010 and 2010/2011 growing seasons at two separate localities for an early and late planting date of corn. Weed-free and weed–crop interference treatments of increasing duration were maintained at various crop growth stages in the presence of naked crabgrass. Biomass of naked crabgrass was determined as dry weight per square meter quadrant, which yielded 428 g m−2at Potchefstroom and 594 g m−2at Wesselsbron. An exponential regression model was used to determine the CPWC expressed as growing degree days after crop emergence, on the basis of an estimated 10% relative yield loss in corn. The onset and ending, as well as the duration of the CPWC, differed between seasons and localities. At 10% relative yield loss, the onset of the CPWC ranged between the two-leaf (V2) and six-leaf (V6) stages, and the ending between the 12-leaf (V12) stage and 2 wk after tasseling (T + 2). The duration of the CPWC ranged between 22 and 80 d for the respective planting dates, years, and localities. Yield losses ranged from 28 to 82% in the season-long weedy plots. The shifting of planting dates alone did not reduce yield losses since the effect of late infestations of naked crabgrass is significant. Naked crabgrass control from crop emergence is essential, followed by POST herbicide application during the critical period of weed control to lower the risk of corn yield losses.

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

Weed Technology ◽

10.1017/wet.2019.28 ◽

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 ◽

Growth Stages ◽

Internode Elongation ◽

Yield Losses ◽

Target Movement ◽

Significant Injury ◽

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.

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Corn Yield Loss Due to Volunteer Soybean

Weed Science ◽

10.1614/ws-d-16-00004.1 ◽

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 Losses ◽

Herbicide Resistant ◽

Growing Seasons ◽

Previous Season ◽

Control Volunteer ◽

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.

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Integrating Economics in the Critical Period for Weed Control Concept in Corn

Weed Science ◽

10.1614/ws-d-13-00184.1 ◽

2014 ◽

Vol 62 (4) ◽

pp. 608-618 ◽

Author(s):

Martina Keller ◽

Geoffroy Gantoli ◽

Jens Möhring ◽

Christoph Gutjahr ◽

Roland Gerhards ◽

...

Keyword(s):

Weed Control ◽

Critical Period ◽

Logistic Models ◽

Crop Growth ◽

Growth Stages ◽

Weed Interference ◽

Free Interval ◽

Crop Growth Stages

The effect of weed interference on corn yield and the critical period for weed control (CPWC) were determined in Germany and Benin. Treatments with weed control starting at different crop growth stages and continuously kept weed-free until harvest represented the “weed-infested interval.” Treatments that were kept weed-free from sowing until different crop growth stages represented the “weed-free interval.” Michaelis–Menten, Gompertz, logistic and log–logistic models were employed to model the weed interference on yield. Cross-validation revealed that the log–logistic model fitted the weed-infested interval data equally well as the logistic and slightly better than the Gompertz model fitted the weed-free interval. For Benin, economic calculations considered yield revenue and cost increase due to mechanical weeding operations. Weeding once at the ten-leaf stage of corn resulted already profitable in three out of four cases. One additional weeding operation may optimize and assure profit. Economic calculations for Germany determined a CPWC starting earlier than the four-leaf stage, challenging the decade-long propagated CPWC for corn. Differences between Germany and Benin are probably due to the higher yields and high costs in Germany. This study provides a straightforward method to implement economic data in the determination of the CPWC for chemical and nonchemical weed control strategies.

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The Critical Period for Weed Control (CPWC) in Potato (Solanum tuberosum L.)

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha43210031 ◽

2015 ◽

Vol 43 (2) ◽

pp. 355-360 ◽

Author(s):

Dogan ISIK ◽

Adem AKCA ◽

Emine KAYA ALTOP ◽

Nihat TURSUN ◽

Husrev MENNAN

Keyword(s):

Weed Control ◽

Weed Management ◽

Critical Period ◽

Field Experiments ◽

Cropping Systems ◽

Control Period ◽

Relative Yield ◽

Weed Interference

Accurate assessment of crop-weed control period is an essential part for planning an effective weed management for cropping systems. Field experiments were conducted during the seasonal growing periods of potato in 2012 and 2013 in Kayseri, Turkey to assess critical period for weed control (CPWC) in potato. A four parameter log-logistic model was used to assist in monitoring and analysing two sets of related, relative crop yield. Data was obtained during the periods of increased weed interference and as a comparison, during weed-free periods. In both years, the relative yield of potato decreased with a longer period of weed-interference whereas increased with increasing length of weed free period. In 2012, the CPWC ranged from 112 to 1014 GDD (Growing Degree Days) which corresponded to 8 to 66 days after crop emergence (DAE) and between 135-958 GDD (10 to 63 DAE) in the following year based on a 5% acceptable yield loss. Weed-free conditions needed to be established as early as the first week after crop emergence and maintained as late as ten weeks after crop emergence to avoid more than 5% yield loss in the potato. The results suggest that CPWC could well assist potato producers to significantly reduce the expense of their weed management programs as well as improving its efficacy.

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Response of Johnsongrass (Sorghum halepense) and Imidazolinone-Resistant Corn (Zea mays) to AC 263,222

Weed Technology ◽

10.1017/s0890037x00046078 ◽

1999 ◽

Vol 13 (3) ◽

pp. 484-488 ◽

Author(s):

John W. Wilcut ◽

John S. Richburg ◽

F. Robert Walls

Keyword(s):

Zea Mays ◽

Weed Control ◽

Untreated Control ◽

Field Studies ◽

Sorghum Halepense ◽

Redroot Pigweed ◽

Herbicide Treatments ◽

Large Crabgrass

Field studies were conducted in 1992 and 1993 to evaluate AC 263,222 applied postemergence (POST) alone and as a mixture with atrazine or bentazon for weed control in imidazolinone-resistant corn. Nicosulfuron alone and nicosulfuron plus atrazine were also evaluated. Herbicide treatments were applied following surface-banded applications of two insecticides, carbofuran or terbufos at planting. Crop sensitivity to POST herbicides, corn yield, and weed control was not affected by insecticide treatments. AC 263,222 at 36 and 72 g ai/ha controlled rhizomatous johnsongrass 88 and 99%, respectively, which was equivalent to nicosulfuron applied alone or with atrazine. AC 263,222 at 72 g/ha controlled large crabgrass 99% and redroot pigweed 100%, and this level of control exceeded that obtained with nicosulfuron alone. AC 263,222 at 72 g/ha controlled sicklepod and morningglory species 99 and 98%, respectively. Nicosulfuron alone or with atrazine controlled these two species less than AC 263,222 at 72 g/ha. Addition of bentazon or atrazine to AC 263,222 did not improve control of any species compared with the higher rate of AC 263,222 at 72 g/ha applied alone. Corn yield increased over the untreated control when POST herbicide(s) were applied, but there were no differences in yield among herbicide treatments.

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Response of Corn to Preemergence and Postemergence Applications of Saflufenacil

Weed Technology ◽

10.1614/wt-08-120.1 ◽

2009 ◽

Vol 23 (3) ◽

pp. 331-334 ◽

Author(s):

Nader Soltani ◽

Christy Shropshire ◽

Peter H. Sikkema

Keyword(s):

Weed Control ◽

Petroleum Hydrocarbons ◽

Field Studies ◽

Yield Losses ◽

Saflufenacil (BAS 800H) is a new herbicide being developed by BASF for PRE broadleaf weed control in corn. Field studies were conducted at two Ontario locations in 2006 and 2007 to evaluate the tolerance of field corn to PRE and POST (spike and two- to three-leaf corn) applications of saflufenacil at 50, 100, and 200 g ai/ha with and without an adjuvant (surfactant blend + solvent [petroleum hydrocarbons]; 1% v/v). Saflufenacil applied PRE reduced corn height by as much as 12% with the highest rate of 200 g/ha; however, corn yield was not affected. When saflufenacil was applied without an adjuvant to corn at the spike stage, injury was as much as 12%, 7 d after treatment (DAT). However, corn height and yield were not affected. Saflufenacil applied POST to two- to three-leaf corn at 50 to 200 g/ha without an adjuvant resulted in as much as 25% injury and reduced corn height 31% but did not affect yield. Adding an adjuvant to POST applications of saflufenacil caused as much as 4 and 99% injury, reduced corn height 13 and 77%, and reduced corn yield 0 and 59% when applied to corn at the spike and at the two- to three-leaf stages, respectively. Based on these results, saflufenacil applied PRE can be safely used in corn at rates up to 200 g/ha. Saflufenacil applied to corn at the spike and two- to three-leaf stage at 50 or 100 g/ha without an adjuvant demonstrated acceptable corn tolerance and may allow for the use of saflufenacil beyond the proposed PRE use pattern. In contrast, applying saflufenacil POST with an adjuvant to spike and two- to three-leaf stage corn resulted in unacceptable injury and yield losses in field corn.

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The Critical Period of Bengal Dayflower (Commelina Bengalensis) Control in Peanut

Weed Science ◽

10.1614/ws-06-181.1 ◽

2007 ◽

Vol 55 (4) ◽

pp. 359-364 ◽

Author(s):

Theodore M. Webster ◽

Wilson H. Faircloth ◽

J. Timothy Flanders ◽

Eric P. Prostko ◽

Timothy L. Grey

Keyword(s):

Weed Control ◽

Critical Period ◽

Plant Pathogens ◽

Maximum Yield ◽

Field Studies ◽

Yield Losses ◽

Competitive Effects ◽

Peanut Crop ◽

The Relationship

Bengal dayflower (also known as tropical spiderwort) is one of the most troublesome weeds in peanut in Georgia, United States. Field studies conducted in 2004 and 2005 evaluated the relationship between the duration of Bengal dayflower interference and peanut yield in an effort to optimize the timing of weed control. In 2004, the critical period of weed control (CPWC) necessary to avoid greater than 5% peanut yield loss was between 316 and 607 growing degree days (GDD), which corresponded to an interval between June 8 and July 2. In 2005, the CPWC ranged from 185 to 547 GDD, an interval between May 30 and July 3. Maximum yield loss in 2005 from season-long interference of Bengal dayflower was 51%. In 2004, production of peanut pods was eliminated by interference with Bengal dayflower for the initial 6 wk (495 GDD) of the growing season. Robust Bengal dayflower growth in 2004 shaded the peanut crop, likely intercepting fungicide applications and causing a reduction in peanut yield. Therefore, the competitive effects of Bengal dayflower are likely complicated with the activity of plant pathogens. In spite of higher Bengal dayflower population densities, greater Bengal dayflower growth, and greater peanut yield losses in 2004 than in 2005, the CPWC was a relatively similar 4-wk period that ended during the first week of July, for peanut that was planted in the first week of May.

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Revisiting Planting Date and Cultivar Effects on Soybean Sudden Death Syndrome Development and Yield Loss

Plant Disease ◽

10.1094/pdis-12-15-1411-re ◽

2016 ◽

Vol 100 (10) ◽

pp. 2152-2157 ◽

Author(s):

David A. Marburger ◽

Damon L. Smith ◽

Shawn P. Conley

Keyword(s):

Sudden Death ◽

Maximum Yield ◽

Planting Date ◽

Sudden Death Syndrome ◽

Yield Potential ◽

Yield Losses ◽

Planting Dates ◽

Soybean Yield ◽

The impact of today’s optimal planting dates on sudden death syndrome (SDS) (caused by Fusarium virguliforme) development and soybean yield loss are not yet well understood. Field trials established in Hancock, Wisconsin during 2013 and 2014 investigated interactions between planting date and cultivar on SDS development and soybean yield. In 2013, disease index (DX) levels differed among cultivars, but results showed no difference between the 6 May and 24 May planting dates. Significantly lower DX levels were observed for the 17 June date. Greatest yields were found in the 6 May planting date, and yield losses were 720 (17%), 770 (20%), and 400 kg ha−1 (12%) for the 6 May, 24 May, 17 and June planting dates, respectively. In 2014, cultivars again differed for DX, but results showed highest DX levels in the 5 May planting date, with little disease observed in the 22 May and 11 June dates. Yield losses were 400 (12%) and 270 kg ha−1 (9%) for the 5 May and 22 May dates, respectively, but no difference was found in the 11 June date. Despite the most symptom development, these results suggest early May planting coupled with appropriate cultivar selection provides maximum yield potential and profitability in Wisconsin.

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Field Pea and Lentil Tolerance to Interrow Cultivation

Weed Technology ◽

10.1017/wet.2017.90 ◽

2017 ◽

Vol 32 (2) ◽

pp. 205-210 ◽

Author(s):

Katherine A. Stanley ◽

Steven J. Shirtliffe ◽

Dilshan Benaragama ◽

Lena D. Syrovy ◽

Hema S. N. Duddu

Keyword(s):

Weed Control ◽

Field Experiments ◽

Growing Season ◽

Field Pea ◽

Crop Damage ◽

Growth Stages ◽

Row Crops ◽

Mechanical Weed Control

AbstractInterrow cultivation is a selective, in-crop mechanical weed control tool that has the potential to control weeds later in the growing season with less crop damage compared with other in-crop mechanical weed control tools. To our knowledge, no previous research has been conducted on the tolerance of narrow-row crops to interrow cultivation. The objective of this experiment was to determine the tolerance of field pea and lentil to interrow cultivation. Replicated field experiments were conducted in Saskatchewan, Canada, in 2014 and 2015. Weekly cultivation treatments began at the 4-node stage of each crop, continuing for 6 wk. Field pea and lentil yield linearly declined with later crop stages of cultivation. Cultivating multiple times throughout the growing season reduced yield by 15% to 30% in both crops. Minimal yield loss occurred when interrow cultivation was conducted once at early growth stages of field pea and lentil; however, yield loss increased with delayed and more frequent cultivation events.

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Growth and Yield Losses of Roundup Ready Soybean as Influenced by Micro-rates of 2,4-D

Sustainable Agriculture Research ◽

10.5539/sar.v10n4p27 ◽

2021 ◽

Vol 10 (4) ◽

pp. 27

Author(s):

Ivan Cuvaca ◽

Stevan Knezevic ◽

Jon Scott ◽

O. Adewale Osipitan

Keyword(s):

Plant Height ◽

Maximum Growth ◽

Growth And Yield ◽

Growth Stages ◽

Spray Drift ◽

Canopy Closure ◽

Yield Losses ◽

Roundup Ready ◽

Timing Of Exposure

Widespread resistance to glyphosate has made weed control very challenging. In response, new approaches to managing resistant biotypes such as the Enlist E3TM have been developed. This technology allows in-crop use of 2,4-D but there is fear associated with unintentional application of the herbicide (e.g. direct application, tank contamination, or spray drift) to sensitive crops. A study was conducted to evaluate Roundup Ready (RR) soybean growth and yield loss as influenced by 2,4-D [six micro rates of 1/5, 1/10, 1/50, 1/100, 1/500 and 1/1000 of the 1,120 g ae ha-1 label recommended dose, and a check with no herbicide applied] applied at V2, R1 and R2 growth stages. In general, RR soybean was more sensitive to 2,4-D at R1 than V2 and R2. The highest 2,4-D rate, 1/5 of the label recommended rate, caused 51% soybean injury symptom, 13 d canopy closure delay, 41.2% plant height reduction, and 68.9% yield loss at R1. Based on effective dose (ED) estimates, 37.7 g ae ha-1 2,4-D caused 5% yield loss (0.23 Mg ha-1) at R1 compared with a 2.5- and 2.0-fold higher dose at V2 and R2, respectively. With respect to number of days to canopy closure, both reproductive stages (R1 and R2) were equally less sensitive to 2,4-D than the vegetative one (V2) as the plants had already achieved maximum growth recorded. On the other hand, ED estimates for plant height have shown that both V2 and R2 were equally more sensitive to 2,4-D than R1. These results clearly indicated that RR soybean growth and yield loss were significantly influenced by the timing of exposure and amount of 2,4-D.

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