The Critical Period for Weed Control: Revisiting Data Analysis

There is an ever-larger need for designing an integrated weed management (IWM) program largely because of the increase in glyphosate-resistant weeds, not only in the United States but also worldwide. An IWM program involves a combination of various methods (cultural, mechanical, biological, genetic, and chemical) for effective and economical weed control (Swanton and Weise 1991). One of the first steps in designing an IWM program is to identify thecritical period for weed control(CPWC), defined as a period in the crop growth cycle during which weeds must be controlled to prevent crop yield losses (Zimdahl 1988).

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Planting date influences critical period of weed control in sweet corn

Weed Science ◽

10.1614/ws-06-005r.1 ◽

2006 ◽

Vol 54 (5) ◽

pp. 928-933 ◽

Cited By ~ 45

Author(s):

Martin M. Williams

Keyword(s):

Weed Control ◽

Weed Management ◽

Critical Period ◽

Sweet Corn ◽

Relative Yield ◽

Planting Date ◽

Integrated Weed Management ◽

Yield Losses ◽

Yield Data ◽

Weed Interference

The critical period for weed control (CPWC) identifies the phase of the crop growth cycle when weed interference results in unacceptable yield losses; however, the effect of planting date on CPWC is not well understood. Field studies were conducted in 2004 and 2005 at Urbana, IL, to determine CPWC in sweet corn for early May (EARLY) and late-June (LATE) planting dates. A quantitative series of treatments of both increasing duration of interference and length of weed-free period were imposed within each planting-date main plot. The beginning and end of the CPWC, based on 5% loss of marketable ear mass, was determined by fitting logistic and Gompertz equations to the relative yield data representing increasing duration of weed interference and weed-free periods, respectively. Weed interference stressed the crop more quickly and to a greater extent in EARLY, relative to LATE. At a 5% yield-loss level, duration of weed interference for 160 and 662 growing-degree days (GDD) from crop emergence marked the beginning of the CPWC for EARLY and LATE, respectively. When maintained weed-free for 320 and 134 GDD, weeds emerging later caused yield losses of less than 5% for EARLY and LATE, respectively. Weed densities exceeded 85 plants m−2for the duration of the experiments and predominant species included barnyardgrass, common lambsquarters, common purslane, redroot pigweed, and velvetleaf. Weed canopy height and total aboveground weed biomass were 300% and 500% higher, respectively, for EARLY compared with LATE. Interactions between planting date and CPWC indicate the need to consider planting date in the optimization of integrated weed management systems for sweet corn. In this study, weed management in mid-June–planted sweet corn could have been less intensive than early May–planted corn, reducing herbicide use and risk of herbicide carryover to sensitive rotation crops.

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Potential yield loss in grain sorghum (Sorghum bicolor) with weed interference in the United States

Weed Technology ◽

10.1017/wet.2020.12 ◽

2020 ◽

Vol 34 (4) ◽

pp. 624-629 ◽

Cited By ~ 1

Author(s):

J. Anita Dille ◽

Phillip W. Stahlman ◽

Curtis R. Thompson ◽

Brent W. Bean ◽

Nader Soltani ◽

...

Keyword(s):

United States ◽

Weed Control ◽

Weed Management ◽

Yield Loss ◽

Science Research ◽

The United States ◽

Grain Sorghum ◽

Control Cost ◽

Potential Yield ◽

Weed Interference

AbstractPotential yield losses in grain sorghum due to weed interference based on quantitative data from the major grain sorghum-growing areas of the United States are reported by the WSSA Weed Loss Committee. Weed scientists and extension specialists who researched weed control in grain sorghum provided data on grain sorghum yield loss due to weed interference in their region. Data were requested from up to 10 individual experiments per calendar year over 10 yr between 2007 and 2016. Based on the summarized information, farmers in Arkansas, Kansas, Missouri, Nebraska, South Dakota, and Texas would potentially lose an average of 37%, 38%, 30%, 56%, 61%, and 60% of their grain sorghum yield with no weed control, and have a corresponding annual monetary loss of US $19 million, 302 million, 7 million, 32 million, 25 million, and 314 million, respectively. The overall average yield loss due to weed interference was estimated to be 47% for this grain sorghum-growing region. Thus, US farmers would lose approximately 5,700 million kg of grain sorghum valued at approximately US $953 million annually if weeds are not controlled. With each dollar invested in weed management (based on estimated weed control cost of US $100 ha−1), there would be a return of US $3.80, highlighting the return on investment in weed management and the importance of continued weed science research for sustaining high grain sorghum yield and profitability in the United States.

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Herbicide Technology for Integrated Weed Management Systems

Weed Science ◽

10.1017/s0043174500060306 ◽

1982 ◽

Vol 30 (S1) ◽

pp. 35-39 ◽

Cited By ~ 3

Author(s):

G. D. Hill

Keyword(s):

Weed Management ◽

Agricultural Production ◽

Food Production ◽

Critical Period ◽

The United States ◽

Integrated Weed Management ◽

Strong Impact ◽

Integrated Crop Management ◽

Economic Forces ◽

Timely Topic

I am honored by your invitation to participate in a symposium on this timely topic. Our twenty-first annual meeting on weed science and technology comes during a critical period of challenging readjustment for agricultural production in the world, especially in the United States. To focus perspective on this subject, I have compiled a list of factors, trends, and economic forces that can exert a strong impact on the future of agriculture, food production, herbicide technology, and integrated crop-management programs during the next 20 yr.

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Light Quality and the Critical Period for Weed Control in Soybean

Weed Science ◽

10.1614/ws-d-11-00072.1 ◽

2012 ◽

Vol 60 (1) ◽

pp. 86-91 ◽

Cited By ~ 28

Author(s):

Emily Green-Tracewicz ◽

Eric R. Page ◽

Clarence J. Swanton

Keyword(s):

Weed Control ◽

Weed Management ◽

Critical Period ◽

Light Quality ◽

Morphological Changes ◽

Management Strategies ◽

Leaf Number ◽

Integrated Weed Management ◽

Weed Competition ◽

Shade Avoidance

The critical period for weed control (CPWC) is an integral component of integrated weed management strategies. Several studies have defined the CPWC in soybean under varying agronomic conditions, yet none have described the mechanisms involved in crop yield losses caused by weed competition. We hypothesized that under nonresource-limiting conditions, morphological changes resulting from the expression of shade avoidance could be used to define a period of developmental sensitivity to low red-to-far-red ratio (R : FR) that would overlap with the defined CPWC in soybean. Two experiments (a sequential harvest and a weed addition/removal series) were conducted in 2008 and 2009 under controlled environmental conditions to address this hypothesis. Two light-quality treatments were used: (1) high R : FR ratio (i.e., weed-free), and (2) low R : FR ratio (i.e., weedy). The low R : FR ratio treatment induced shade avoidance responses in soybean, which included increases in height, internode length, and the shoot : root ratio, as well as a reduction in biomass accumulation and leaf number. Using the morphological changes in biomass and leaf number observed in the weed addition/removal series, a period of developmental sensitivity to low R : FR was defined between the first trifoliate (V1) and third trifoliate (V3) stages of soybean development. This period was found to be very similar to the CPWC previously defined by field studies of soybean–weed competition.

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Weed management in direct seeded rice: A review

Agricultural Reviews ◽

10.18805/ag.v0iof.7307 ◽

2017 ◽

Cited By ~ 1

Author(s):

Sheeja K Raj ◽

Elizabeth K Syriac

Keyword(s):

Weed Control ◽

Weed Management ◽

Sustainable Management ◽

Critical Period ◽

Seedling Emergence ◽

Management Strategies ◽

Integrated Weed Management ◽

Weed Flora ◽

Direct Seeded

Weeds are the major biological constraint in direct seeded rice (DSR) due to the concurrent emergence of competitive weeds, absence of water to suppress weeds at the time of seedling emergence and emergence of difficult to control weeds. Strategies on weed management in direct seeded rice depend on critical period of weed control, weed flora and method to be adopted. In order to achieve the long term and sustainable management of weeds in DSR an integration of different weed management strategies like integrated weed management (IWM) are essential. The literature regarding the critical period of weed control, weed flora and different methods for the sustainable management of weeds in direct seeded rice are reviewed in this paper.

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Vegetable Soybean Tolerance to Bentazon, Fomesafen, Imazamox, Linuron, and Sulfentrazone

Weed Technology ◽

10.1614/wt-d-14-00019.1 ◽

2014 ◽

Vol 28 (4) ◽

pp. 601-607 ◽

Cited By ~ 9

Author(s):

Martin M. Williams ◽

Randall L. Nelson

Keyword(s):

United States ◽

Weed Management ◽

Herbicide Tolerance ◽

The United States ◽

Field Trials ◽

Management Systems ◽

Integrated Weed Management ◽

Vegetable Soybean ◽

Growth Reduction ◽

Crop Tolerance

Poor weed control, resulting from limited herbicide availability and undeveloped integrated weed management systems, is a major hurdle to production of vegetable soybean in the United States. Vegetable soybean, the same species as grain-type soybean, has few registered herbicides because of unknown crop tolerance. Tolerance of as many as 128 vegetable soybean entries to a 2X registered rate of bentazon, fomesafen, imazamox, linuron, and sulfentrazone were quantified within 4 wk after treatment in field trials. Several grain-type soybean entries were included for comparison, including entries with known herbicide tolerance or sensitivity. Injury and seedling growth reduction to all vegetable entries was comparable to all grain-type entries for fomesafen, linuron, and sulfentrazone; and less than all grain-type entries for bentazon and imazamox. Responses of ten of the more widely used vegetable soybean entries were comparable to grain-type entries with known herbicide tolerance. Bentazon, fomesafen, imazamox, linuron, and sulfentrazone pose no greater risk of adverse crop response to vegetable soybean germplasm than the grain-type soybean to which they have been applied for years. Since initiation of this research, fomesafen, imazamox, and linuron are now registered for use on the crop in the United States. Development of integrated weed management systems for vegetable soybean would benefit from additional herbicide registrations.

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Critical Period of Weed Control in Aerobic Rice

The Scientific World JOURNAL ◽

10.1100/2012/603043 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10 ◽

Cited By ~ 6

Author(s):

M. P. Anwar ◽

A. S. Juraimi ◽

B. Samedani ◽

A. Puteh ◽

A. Man

Keyword(s):

Weed Control ◽

Weed Management ◽

Critical Period ◽

Yield Loss ◽

Field Trials ◽

Integrated Weed Management ◽

Aerobic Rice ◽

View Point ◽

Weed Interference ◽

Economic View

Critical period of weed control is the foundation of integrated weed management and, hence, can be considered the first step to design weed control strategy. To determine critical period of weed control of aerobic rice, field trials were conducted during 2010/2011 at Universiti Putra Malaysia. A quantitative series of treatments comprising two components, (a) increasing duration of weed interference and (b) increasing length of weed-free period, were imposed. Critical period was determined through Logistic and Gompertz equations. Critical period varied between seasons; in main season, it started earlier and lasted longer, as compared to off-season. The onset of the critical period was found relatively stable between seasons, while the end was more variable. Critical period was determined as 7–49 days after seeding in off-season and 7–53 days in main season to achieve 95% of weed-free yield, and 23–40 days in off-season and 21–43 days in main season to achieve 90% of weed-free yield. Since 5% yield loss level is not practical from economic view point, a 10% yield loss may be considered excellent from economic view point. Therefore, aerobic rice should be kept weed-free during 21–43 days for better yield and higher economic return.

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Extending the critical period for weed control model to better include weed succession using common sunflower as a mimic weed in high-yielding cotton

Weed Technology ◽

10.1017/wet.2021.91 ◽

2021 ◽

pp. 1-27

Author(s):

Graham W. Charles ◽

Ian N. Taylor

Keyword(s):

Weed Control ◽

Weed Management ◽

Critical Period ◽

Yield Loss ◽

Logistic Function ◽

Integrated Weed Management ◽

Traditional Practice ◽

Crop Planting ◽

Logistic Functions ◽

Weed Emergence

Abstract The critical period for weed control (CPWC) adds value to integrated weed management by identifying the period during which weeds need to be controlled to avoid yield losses exceeding a defined threshold. However, the traditional application of the CPWC does not identify the timing of control needed for weeds that emerge late in the critical period. In this study, CPWC models were developed from field data in high yielding cotton crops during three summer seasons from 2005 to 2008, using the mimic weed; common sunflower, at densities of 2 to 20 plants m−2. Common sunflower plants were introduced at up to 450 growing degree days (GDD) after crop planting and removed at successive 200 GDD intervals after introduction. The CPWC models were described using extended Gompertz and logistic functions that included weed density, time of weed introduction and time of weed removal (logistic function only) in the relationships. The resulting models defined the CPWC for late emerging weeds, identifying a period after weed emergence before weed control was required to prevent yield loss exceeding the yield-loss threshold. Where weeds emerged in sufficient numbers toward the end of the critical period, the model predicted that crop yield loss resulting from competition by these weeds would not exceed the yield-loss threshold until well after the end of the CPWC. These findings support the traditional practice of ensuring weeds are controlled before crop canopy closure, with later weed control inputs used as required.

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Response of Energycane to Preemergence and Postemergence Herbicides

Weed Technology ◽

10.1614/wt-d-15-00033.1 ◽

2015 ◽

Vol 29 (4) ◽

pp. 810-820 ◽

Cited By ~ 2

Author(s):

Dennis C. Odero ◽

Jose V. Fernandez ◽

Hardev S. Sandhu ◽

Maninder P. Singh

Keyword(s):

United States ◽

Weed Control ◽

Weed Management ◽

Perennial Grass ◽

Belowground Biomass ◽

The United States ◽

Bioenergy Crop ◽

Fuel Production ◽

Aboveground And Belowground Biomass ◽

Postemergence Herbicides

Energycane has been proposed as a potential, perennial bioenergy crop for lignocellulosic-derived fuel production in the United States. Herbicides currently used in sugarcane and other crops can potentially be used in energycane if there is acceptable tolerance. Also, to limit future invasion of energycane escapes, herbicides used for perennial grass control could potentially be used for management of escapes. In container studies conducted outside, aboveground and belowground biomass of energycane was measured to evaluate energycane tolerance to 9 PRE and 19 POST herbicides used in sugarcane and other crops. PRE application of atrazine, diuron, mesotrione, metribuzin, pendimethalin, andS-metolachlor at rates labeled for sugarcane did not significantly injure (< 3%) or reduce energycane biomass compared with the nontreated plants 28 and 56 d after treatment (DAT). Injury from clomazone (54%), flumioxazin (7%), and hexazinone (29%) was observed 28 DAT. Injury from flumioxazin was transient and was not observed at 56 DAT. At 56 DAT, energycane injury increased to 71 and 98%, respectively, for clomazone and hexazinone. Hexazinone and clomazone applied PRE significantly reduced biomass compared with the nontreated plants. At 28 DAT, POST application of 2,4-D amine, ametryn, asulam, atrazine, carfentrazone, dicamba, halosulfuron, mesotrione, metribuzin, and trifloxysulfuron at labeled rates for sugarcane did not injure or significantly reduce energycane biomass compared with the nontreated plants. Injury was observed when clethodim (99%), clomazone (51%), diuron (51%), flumioxazin (21%), glufosinate (84%), glyphosate (100%), hexazinone (100%), paraquat (66%), and sethoxydim (100%) were applied POST, and each of these treatments reduced energycane biomass compared with the nontreated plants. These results show that several PRE and POST herbicides used for weed management in sugarcane may potentially be used in energycane for weed control. Also, based on our results, clethodim, glyphosate, and sethoxydim would be effective for management of energycane escapes.

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Combate de coyolillo (Cyperus rotundus) en caña de azúcar (Saccharum off'icinarum L.): hacia un manejo integral.

Agronomía Mesoamericana ◽

10.15517/am.v8i2.24668 ◽

2016 ◽

Vol 8 (2) ◽

pp. 101

Author(s):

Carlos Segura N. ◽

Renán Agüero A.

Keyword(s):

Weed Control ◽

Crop Yield ◽

Weed Management ◽

Production Cost ◽

Cyperus Rotundus ◽

Integrated Weed Management ◽

Purple Nutsedge ◽

History Of Agriculture ◽

History Of ◽

Tillage Treatment

Weed control is an important component of the production cost of sugarcane thus, it should be performed in a rational manner. The history of agriculture is rich i examples that confirm the integrated weed management(IWM) strategy as the most sustainable. An experiment comparing herbicides herbicides-tillage, tillage, and band control against whole area control was conductedin a field with ahistory ofhigh infestations of purple nutsedge (Cyperus rotundus L.). Pyrazosulfuron-etil preemergence to the crop folIowed by 2,4-D postemergence to the crop showed a population of the weed similar to the glyphosate/tillage treatment as well as to the tillage/tillage treatment, in alI cases, significantly lower than the weedy check. Weed control over the whole area was equivalent to weed control in bands of 25 cm to each side of the crop rows in terms of crop yield. Other alternatives that might be used as part of an integrated weed management in conjunction with the best treatments found in this experiment are discussed.

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