Rate and Time of Bentazon/Atrazine Application for Broadleaf Weed Control in Corn (Zea mays)

1997 ◽  
Vol 11 (3) ◽  
pp. 549-555 ◽  
Author(s):  
Allan S. Hamill ◽  
Jianhua Zhang
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Lower Cost ◽  
Yield Loss ◽  
Small Range ◽  
Corn Yield ◽  
Weed Density ◽  
Time Of Application ◽  
Intermediate Rate ◽  
Range Of Variation

The effects of herbicide–adjuvant combinations and times of application on weed density and corn yield were determined in a 3-yr field study. At a given rate and time of application of bentazon/atrazine, Assist and Merge were equally effective adjuvants. Assist would be the adjuvant of choice for bentazon/atrazine rather than Merge because of its currently lower cost. Weed density depended on the rate and time of application of bentazon/atrazine. In general, bentazon/atrazine applied at early stages (7 d after emergence) of the development of corn seedlings or at high or intermediate rate (1.6 or 0.8 kg ai/ha) maintained low weed densities, with a relatively small range of variation over years. Delay in time (14 or 21 d after emergence) or reduction in herbicide rate (0.4 kg ai/ha) increased the risk of high weed pressure, although it was not always associated with yield loss. The best time for the application of postemergence herbicide appears to be a few days prior to the onset of the critical period of weed control.

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.

Influence of a Rye Cover Crop on the Critical Period for Weed Control in Cotton

Weed Science ◽  
2015 ◽  
Vol 63 (1) ◽  
pp. 346-352 ◽  
Author(s):  
Nicholas E. Korres ◽  
Jason K. Norsworthy
Keyword(s):  
Weed Control ◽  
Cover Crops ◽  
Cover Crop ◽  
Critical Period ◽  
Yield Loss ◽  
Growing Season ◽  
Weed Biomass ◽  
Weed Density ◽  
Presence And Absence ◽  
Weed Removal

Cover crops are becoming increasingly common in cotton as a result of glyphosate-resistant Palmer amaranth; hence, a field experiment was conducted in 2009 and 2010 in Marianna, AR, with a rye cover crop used to determine its effects on the critical period for weed control in cotton. Throughout most of the growing season, weed biomass in the presence of a rye cover crop was lesser than that in the absence of a rye cover crop. In 2009, in weeks 2 through 7 after planting, weed biomass was reduced at least twofold in the presence of a rye cover compared with the absence of rye. In 2009, in both presence and absence of a rye cover crop, weed removal needed to begin before weed biomass was 150 g m−2, or approximately 4 wk after planting, to prevent yield loss > 5%. Weed density was less in 2010 than in 2009, so weed removal was not required until 7 wk after planting, at which point weed biomass values were 175 and 385 g m−2in the presence and absence of a cover crop, respectively.

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.

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.

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

Weed Science ◽  
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 ◽  
Corn Yield ◽  
Leaf Stage ◽  
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.

The Effect of Trifluralin Applied Preplant on Grass Weed Control and Establishment and Yield of Barley (Hordeum vulgare)

1997 ◽  
Vol 11 (3) ◽  
pp. 515-519 ◽  
Author(s):  
Julio A. Scursoni ◽  
Emilio H. Satorre
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Herbicide Application ◽  
Planting Pattern ◽  
Weed Density ◽  
Time Of Application ◽  
Density And Biomass ◽  
And Control ◽  
Crop Planting ◽  
Grass Weed

The objective of this paper was to evaluate the effect of preplant applications of trifluralin on barley stand and yield, and control of grass weeds in field experiments during 1992 and 1993. Factors examined were: (1) crop planting patterns (conventional drill with rows 15 cm apart and deep-seeder drill with rows 25 cm apart), (2) herbicide application times (22 d before sowing and immediately before sowing), and (3) herbicide application. During 1993, hand-weeded plots also were established. Trifluralin applied preplant at 528 g ai/ha reduced weed density and biomass. Weed control was higher under conventional planting than under the deep planting pattern, and there was no effect of the time of application on herbicide efficacy. There was no herbicide injury to the crop, and grain yield was higher in treated than in untreated plots due to successful weed control.

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

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 ◽  
Yield Loss ◽  
Cropping Systems ◽  
Control Period ◽  
Relative Yield ◽  
Yield Data ◽  
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.

Decision Rules for Postemergence Control of Pigweed (Amaranthusspp.) in Soybean (Glycine max)

Weed Science ◽  
1996 ◽  
Vol 44 (1) ◽  
pp. 126-132 ◽  
Author(s):  
Anita Dieleman ◽  
Allan S. Hamill ◽  
Glenn C. Fox ◽  
Clarence J. Swanton
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Economic Model ◽  
Yield Loss ◽  
Control Function ◽  
Decision Rules ◽  
Optimal Dose ◽  
Weed Species ◽  
Weed Density ◽  
Control Decision

Weed control decision rules were derived for the application of postemergence herbicides to control pigweed species in soybean. Field experiments were conducted at two locations in 1992 and 1993 to evaluate soybean-pigweed interference. A damage function was determined that related yield loss to time of pigweed emergence, density, and soybean weed-free yield. A control function described pigweed species response to variable doses of imazethapyr and thifensulfuron. The integration of these two functions formed the basis of an economic model used to derive two weed control decision rules, the biologist's “threshold weed density” and the economist's “optimal dose.” Time of weed emergence had a more significant role than weed density in the economic model. Later-emerging pigweed caused less yield loss and therefore, decision rules lead to overuse of herbicides if emergence time is not considered. The selected herbicide dose influenced the outcome of the control function. Depending on the desired level of weed control, a herbicide could be chosen to either eradicate the escaped weed species (label or biologically-effective doses) or reduce the growth of the weed species and thereby offset interference (optimal dose). The development of a biologically-effective dose by weed species matrix was recommended. Decision rules should not be utilized as an exclusive weed management strategy but rather as a component of an integrated weed management program.

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.

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