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

Weed Science ◽  
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 ◽  
Yield Loss ◽  
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.

Cotton Planting Date Affects The Critical Period of Benghal Dayflower (Commelina benghalensis) Control

Weed Science ◽  
2009 ◽  
Vol 57 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Theodore M. Webster ◽  
Timothy L. Grey ◽  
J. Timothy Flanders ◽  
A. Stanley Culpepper
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Maximum Yield ◽  
Growing Season ◽  
Field Studies ◽  
Cotton Field ◽  
Commelina Benghalensis ◽  
Critical Range ◽  
Benghal Dayflower

Benghal dayflower (formerly known as tropical spiderwort) is one of the most troublesome weeds in Georgia cotton. Field studies were conducted from 2003 to 2005 to evaluate the relationship between the duration of Benghal dayflower interference and cotton yield to establish optimum weed-control timing. To determine the critical period of weed control (CPWC), Benghal dayflower interference with cotton was allowed or prohibited in 2-wk intervals between 0 to 12 wk after crop planting. Maximum yield loss from Benghal dayflower in May-planted cotton was 21 to 30% in 2004 and 2005, whereas cotton planting delayed until June resulted in maximum yield losses of 40 to 60%. June-planted cotton had a CPWC of 190 to 800 growing degree days (GDD) in 2004 (52-d interval beginning at 16 d after planting [DAP]) and 190 to 910 GDD in 2005 (59-d interval beginning at 18 DAP). In contrast, May-planted cotton in 2005 had a narrower CPWC interval of 396 to 587 GDD (18 d) that occurred 3 wk later in the growing season (initiated at 39 DAP). May-planted cotton in 2004 did not have a critical range of weed-free conditions. Instead, a single weed removal at 490 GDD (44 DAP) averted a yield loss greater than 5%. It is recommended that fields infested with Benghal dayflower be planted with cotton early in the growing season to minimize weed interference with the crop.

Determining the critical period for broadleaf weed control in high-yielding cotton using mungbean as a mimic weed

2020 ◽  
Vol 34 (5) ◽  
pp. 689-698
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Critical Time ◽  
Field Studies ◽  
Cotton Field ◽  
Control Input ◽  
Degree Days ◽  
Weed Density ◽  
The Relationship

AbstractResearch using the critical period for weed control (CPWC) has shown that high-yielding cotton crops are very sensitive to competition from grasses and large broadleaf weeds, but the CPWC has not been defined for smaller broadleaf weeds in Australian cotton. Field studies were conducted over five seasons from 2003 to 2015 to determine the CPWC for smaller broadleaf weeds, using mungbean as a mimic weed. Mungbean was planted at densities of 1, 3, 6, 15, 30, and 60 plants m−2 with or after cotton emergence and added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 degree days of crop growth (GDD). Mungbean competed strongly with cotton, with season-long interference; 60 mungbean plants m−2 resulted in an 84% reduction in cotton yield. A dynamic CPWC function was developed for densities of 1 to 60 mungbean plants m−2 using extended Gompertz and exponential curves including weed density as a covariate. Using a 1% yield-loss threshold, the CPWC defined by these curves extended for the full growing season of the crop at all weed densities. The minimum yield loss from a single weed control input was 35% at the highest weed density of 60 mungbean plants m−2. The relationship for the critical time of weed removal was further improved by substituting weed biomass for weed density in the relationship.

scholarly journals Determining the critical period for weed control in high-yielding cotton using common sunflower as a mimic weed

2019 ◽  
Vol 33 (6) ◽  
pp. 800-807 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Growing Degree Days ◽  
Degree Days ◽  
Weed Density ◽  
High Level ◽  
The Cost ◽  
Planting Season

AbstractField studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.

Determining the critical period for grass control in high-yielding cotton using Japanese millet as a mimic weed

2019 ◽  
Vol 34 (2) ◽  
pp. 292-300 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Cotton Yield ◽  
Degree Days ◽  
Cropping Season ◽  
High Level ◽  
The Cost ◽  
Grass Weed

AbstractField studies were conducted over five seasons from 2004 to 2015 to determine the critical period for weed control (CPWC) in high-yielding, irrigated cotton using a competitive mimic grass weed, Japanese millet. Japanese millet was planted with or after cotton emergence at densities of 10, 20, 50, 100, and 200 plants m−2. Japanese millet was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 degree days of crop growth (GDD). Data were combined over years. Japanese millet competed strongly with cotton, with season-long interference resulting in an 84% reduction in cotton yield with 200 Japanese millet plants m−2. The data were fit to extended Gompertz and logistic curves including weed density as a covariate, allowing a dynamic CPWC to be estimated for densities of 10 to 200 Japanese millet plants m−2. Using a 1% yield-loss threshold, the CPWC commenced at 65 GDD, corresponding to 0 to 7 d after crop emergence (DAE), and ended at 803 GDD, 76 to 98 DAE with 10 Japanese millet plants m−2, and 975 GDD, 90 to 115 DAE with 200 Japanese millet plants m−2. These results highlight the high level of weed control required throughout the cropping season in high-yielding cotton to ensure crop losses do not exceed the cost of weed control.

The Critical Period for Weed Control in Corn in Turkey

2006 ◽  
Vol 20 (4) ◽  
pp. 867-872 ◽  
Author(s):  
Dogan Isik ◽  
Husrev Mennan ◽  
Bekir Bukun ◽  
Ahmet Oz ◽  
Mathieu Ngouajio
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Relative Yield ◽  
Field Studies ◽  
The Black Sea ◽  
Yield Data ◽  
Black Sea Region ◽  
Weed Interference ◽  
Loss Level

Field studies were conducted in 2001 and 2002 in the Black Sea Region of northern Turkey to determine the critical period for weed control (CPWC) in corn and the effects of weed interference on corn height. Treatments of increasing duration of weed interference and weed-free period were imposed at weekly intervals from 0 to 12 wk after crop emergence (WAE). The CPWC was determined with the use of 2.5, 5, and 10% acceptable yield loss levels by fitting logistic and Gompertz equations to relative yield data. With 5% yield loss level, the CPWC was 5 wk, starting at 0.2 WAE and ending at 5.2 WAE, which corresponded to the one- to five-leaf stage of corn. The CPWC increased to 8.9 wk, starting at 0 WAE and ending at 8.9 WAE, at the 2.5% yield loss level. At 10% yield loss level, the CPWC decreased to 1.7 wk, starting at 2.1 WAE and ending at 3.8 WAE.

Estimation of Critical Period of Weed Control

Weed Science ◽  
1996 ◽  
Vol 44 (2) ◽  
pp. 273-283 ◽  
Author(s):  
M. Singh ◽  
M. C. Saxena ◽  
B. E. Abu-Irmaileh ◽  
S. A. Al-Thahabi ◽  
N. I. Haddad
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Field Experiments ◽  
Control Strategies ◽  
Maximum Yield ◽  
Logistic Function ◽  
Weed Infestation ◽  
Using Data ◽  
Relationship Of ◽  
The Relationship

An estimation of the critical period of weed control is helpful in formulating appropriate weed-control strategies. A regression approach is presented to estimate the thresholds of critical period of weed control and time of equal interference (or time of onset of competition). In this approach, yields were either a linear or logistic function of the duration of weed-free and weed-infested periods. Confidence intervals of the thresholds of critical period and time of equal interference were determined for the linear model. An approximation to the standard error of critical period and associated confidence interval were given for any general form of the model. The method was applied to estimate the critical period of weed control in rainfed lentil using data from four field experiments conducted in Jordan. The relationship of yield with the duration of weed-free period was described by a linear function, whereas the relationship with the duration of weed-infested period showed a better fit with a logistic function. To maintain 90% of maximum seed yield, the maximum time allowed to let weeds grow after the crop emergence varied over locations from 4.8 to 5.8 wk. The same level could be achieved if the crop is kept free of weeds from its emergence until 12.1 to 14.1 wk; while the time when the same amount of yield would be achieved under both approaches varied from 7.7 to 9.3 wk after crop emergence. For straw yield, the time to get 90% of the maximum yield could vary over location from a maximum of 4.5 to 8.0 wk under weed-infestation and from at least 11.5 to 13.5 wk when weed-free. The time to achieve the same amount of straw under two systems of competition varied from 6.5 to 9.9 wk after crop emergence. One of the four experiments showed a longer critical period than the others for seed and straw yields.

Lanceleaf Sage (Salvia reflexa) Interference in Sugarbeet

2010 ◽  
Vol 24 (4) ◽  
pp. 557-561 ◽  
Author(s):  
Dennis C. Odero ◽  
Abdel O. Mesbah ◽  
Stephen D. Miller ◽  
Andrew R. Kniss
Keyword(s):  
Yield Loss ◽  
Maximum Yield ◽  
Field Studies ◽  
Control Measures ◽  
Root Yield ◽  
Rectangular Hyperbola ◽  
Weed Density ◽  
Negative Effect ◽  
Critical Timing ◽  
The Relationship

Field studies were conducted in Powell, WY, in 2006 and 2007 to determine the influence of season-long interference of various lanceleaf sage densities and durations of interference on sugarbeet. The rectangular hyperbola model with the asymptote (A) constrained to 100% maximum yield loss characterized the relationship between lanceleaf sage density and sugarbeet yield loss. The estimated parameterI(yield loss per unit weed density as density approaches zero) was 3% for both root and sucrose yield loss. Increasing duration of lanceleaf sage interference had a negative effect on sugarbeet root yield. The critical timing of weed removal to avoid 5 and 10% root yield loss was 37 and 52 d after sugarbeet emergence, respectively. Lanceleaf sage interference did not affect percentage of sucrose content. These results indicate that lanceleaf sage is not as competitive as other weeds but that appropriate control measures should be undertaken to minimize sugarbeet yield loss from interference.

scholarly journals Understanding the Competitive Effects of Blessed Milkthistle Densities on Wheat

2020 ◽  
Vol 38 ◽  
Author(s):  
A. REHMAN ◽  
R. QAMAR ◽  
M.E. SAFDAR ◽  
H.M.R. JAVEED ◽  
M. SHEHZAD ◽  
...  
Keyword(s):  
Weed Management ◽  
Yield Loss ◽  
Cost Effective ◽  
Field Studies ◽  
Wheat Crop ◽  
Yield Losses ◽  
Comprehensive Understanding ◽  
Gradual Reduction ◽  
Competitive Effects ◽  
1000 Grain Weight

ABSTRACT: Weed-induced yield loss in wheat crop is a great threat to food security in Pakistan. A comprehensive understanding of weed-crop competition is very important to develop sustainable and cost-effective weed management. For this purpose, two-year field studies were conducted to determine the effect of different blessed milkthistle densities on the phenology and yield of wheat crop in a rice-wheat cropping scheme in Sargodha, Pakistan during 2013-2014 and 2014-2015. The experiment comprised seven treatments: control (weed free), weedy check (weedy without any control) and blessed milkthistle densities of 5, 10, 15, 20 and 25 plants m-2. In response to increasing weed density, a gradual reduction in yield and yield-related traits of wheat was noted. Compared to the weed-free control, a significant reduction in number of productive tillers m-2 (20% and 18%), plant height (15% and 18%), spike length (19% and 26%), number of grains spike-1 (23% and 26%), 1000 grain weight (28% and 28%), grain (29% and 30%) and biological (20% and 24%) yields of wheat occurred at and beyond blessed milkthistle density of 5 plants m-2 during 2013-2014 and 2014-2015 respectively. It can be concluded that blessed milkthistle weed must be controlled if its population density reaches 5 plants m-2 in order to avoid significant grain yield losses in wheat.

Critical period for weed control in field pea

2015 ◽  
Author(s):  
Mainpal Singh ◽  
Rakesh Kumar ◽  
Satish Kumar ◽  
Virender Kumar
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Crop Growth ◽  
Field Pea ◽  
Control Measures ◽  
Growth And Yield ◽  
Weed Competition ◽  
Weed Density

Field studies were conducted during 2008-09 and 2009-10 at Hisar, India to assess the effect of weed competition on crop growth and yield of field pea. Weed density increased up to 60 days and then decreased at later stages of crop growth. Seed yield of field pea was decreased by 50% when weeds were allowed to compete for the entire season. The critical period for weed control was 21-63 days in year 1 and 20-70 days in year 2 to achieve 95% of weed-free yield. It is therefore concluded that, to minimize yield loss due to weed competition in field pea, weed control measures should be targeted to avoid weed competition between 20-70 days after sowing.

The Critical Period of Weed Control in White Bean (Phaseolus vulgaris)

Weed Science ◽  
1993 ◽  
Vol 41 (2) ◽  
pp. 180-184 ◽  
Author(s):  
Brian L. Woolley ◽  
Thomas E. Michaels ◽  
Michael R. Hall ◽  
Clarence J. Swanton
Keyword(s):  
Phaseolus Vulgaris ◽  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Weed Biomass ◽  
Weed Interference ◽  
Stages Of Growth ◽  
White Bean ◽  
Pod Number

Field studies were conducted in 1986 and 1987 to determine the critical period for weed control in white bean grown in Ontario. The treatments consisted of either allowing weeds to infest the crop for increasing durations after planting or maintaining plots weed free for increasing durations after planting. The beginning of the critical period was defined as the crop stage by which weed interference reduced yields by 3%. Similarly, the end of the critical period was defined as the crop stage to which the crop had to be weed free to prevent a 3% yield loss. The critical period of weed control occurred between the second-trifoliolate and first-flower stages of growth for all cultivars and years, with the exception of the cultivar ‘OAC Seaforth’ in 1986. The average number of pods per plant for both cultivars was reduced by increasing durations of weed interference after planting in both years. However, pod number of the cultivar OAC Seaforth was reduced at a greater rate in 1986 than ‘Ex Rico 23’. The beginning of the critical period corresponded with the beginning of a rapid increase in total weed biomass.

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