Herbicide Timing and Rate Effects on Weed Management in Three Herbicide-Resistant Canola Systems

2004 ◽  
Vol 18 (4) ◽  
pp. 1006-1012 ◽  
Author(s):  
K. Neil Harker ◽  
George W. Clayton ◽  
John T. O'Donovan ◽  
Robert E. Blackshaw ◽  
F. Craig Stevenson
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Management Practices ◽  
Integrated Weed Management ◽  
Weed Biomass ◽  
Herbicide Resistant ◽  
Leaf Stage ◽  
Rate Effects ◽  
Herbicide Timing ◽  
Weed Removal

Herbicide-resistant canola dominates the canola market in Canada. A multiyear field experiment was conducted at three locations to investigate the effect of time of weed removal (two-, four-, or six-leaf canola) and herbicide rate (50 or 100% recommended) in three herbicide-resistant canola systems. Weeds were controlled in glufosinate-resistant canola (GLU) with glufosinate, in glyphosate-resistant canola (GLY) with glyphosate, and in imidazolinone-resistant canola (IMI) with a 50:50 mixture of imazamox and imazethapyr. Canola yields were similar among the three canola cultivar–herbicide systems. Yields were not influenced by 50 vs. 100% herbicide rates. Timing of weed removal had the greatest effect on canola yield, with weed removal at the four-leaf stage giving the highest yields in most cases. Percent dockage was often greater for GLU and IMI than for GLY. In comparison with the other treatments, dockage levels doubled for GLU after application at 50% herbicide rates. The consistency of monocot weed control was usually greater for GLY than for GLU or IMI systems. However, weed biomass data revealed no differences in dicot weed control consistency between IMI and GLY systems. Greater dockage and weed biomass variability after weed removal at the six-leaf stage or after low herbicide rates suggests higher weed seed production, which could constrain the adoption of integrated weed management practices in subsequent years.

Economics of integrated weed management in herbicide-resistant canola

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 138-147 ◽  
Author(s):  
Bharat M. Upadhyay ◽  
Elwin G. Smith ◽  
G. W. Clayton ◽  
K. N. Harker ◽  
R. E. Blackshaw
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Production Systems ◽  
Statistical Significance ◽  
Integrated Weed Management ◽  
Seeding Rate ◽  
Herbicide Resistant ◽  
Leaf Stage ◽  
Weed Removal

Integrated weed management (IWM) decision strategies in herbicide-resistant canola-production systems were assessed for net returns and relative risk. Data from two field experiments conducted during 1998 to 2000 at two locations in Alberta, Canada, were evaluated. A herbicide-based experiment included combinations of herbicide system (glufosinate-, glyphosate-, and imazethapyr-resistant canola varieties), herbicide rate (50 and 100% of recommended dose), and time of weed removal (two-, four-, and six-leaf stages of canola). A seed-based experiment included canola variety (hybrid and open-pollinated), seeding rate (100, 150, and 200 seeds m−2), and time of weed removal (two-, four-, and six-leaf stages of canola). For the herbicide-based experiment, strategies with glyphosate were profitable at Lacombe, but both imazethapyr and glyphosate strategies were profitable at Lethbridge. Weed control at the four-leaf stage was at least as profitable as the two-leaf stage at both sites. For the seed-based experiment, the hybrid was more profitable than the open-pollinated cultivar, seed rates of 100 and 150 seeds m−2were more profitable than 200 seeds m−2, and weed control at the two- and four-leaf stages was more profitable than at the six-leaf stage. When risk of returns and statistical significance was considered, several strategies were included in the risk-efficient set for risk-averse and risk-neutral attitudes at each location. However, the glyphosate-resistant cultivar, the 50% herbicide rate, and weed control at four-leaf stage were more frequent in the risk-efficient IWM strategy set. The open-pollinated cultivar, 200 seeds m−2rate, and weed control at the six-leaf stage were less frequent in the set. The risk-efficient sets of IWM strategies were consistent across a range of canola prices.

Grain grower perceptions and use of integrated weed management

2004 ◽  
Vol 44 (10) ◽  
pp. 993 ◽  
Author(s):  
R. S. Llewellyn ◽  
R. K. Lindner ◽  
D. J. Pannell ◽  
S. B. Powles
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Management Practices ◽  
Economic Value ◽  
Cost Effective ◽  
Farming System ◽  
Integrated Weed Management ◽  
Management Decision ◽  
Herbicide Resistant ◽  
Management Decision Making

Greater adoption of integrated weed management, to reduce herbicide reliance, is an objective of many research and extension programmes. In Australian grain-growing regions, integrated weed management is particularly important for the management of herbicide resistance in weeds. In this study, survey data from personal interviews with 132 Western Australian grain growers are used to characterise the use and perceptions of integrated weed management practices. The main objective was to identify opportunities for improved weed management decision making, through targeted research and extension. The extent to which integrated weed management practices are used on individual farms was measured. Perceptions of the efficacy and reliability of various weed management practices were elicited for control of annual ryegrass (Lolium rigidum Gaud.), along with perceptions of the economic value of integrated weed management practices relative to selective herbicides. All growers were shown to be using several integrated weed management practices, although the use of some practices was strongly associated with the presence of a herbicide-resistant weed population. In general, both users and non-users were found to have high levels of awareness of integrated weed management practices and their weed control efficacy. Herbicide-based practices were perceived to be the most cost-effective. Opportunities for greater adoption of integrated weed management practices, to conserve the existing herbicide resource, exist where practices can be shown to offer greater shorter-term economic value, not necessarily just in terms of weed control, but to the broader farming system.

Effect of Seeding Rate on Dose Response of Wild Mustard (Sinapis arvensis) to Fluthiacet-Methyl

Weed Science ◽  
2017 ◽  
Vol 65 (4) ◽  
pp. 525-533 ◽  
Author(s):  
Collen Redlick ◽  
Hema S. N. Duddu ◽  
Lena D. Syrovy ◽  
Christian J. Willenborg ◽  
Eric N. Johnson ◽  
...  
Keyword(s):  
Weed Control ◽  
Dose Response ◽  
Weed Management ◽  
Management Practices ◽  
Indian Mustard ◽  
Integrated Weed Management ◽  
Seeding Rate ◽  
Weed Biomass ◽  
Wild Mustard ◽  
Seed Yields

Concern over the development of herbicide-resistant weeds has led to interest in integrated weed management systems that reduce selection pressure by utilizing mechanical and cultural weed control practices in addition to herbicides. Increasing crop seeding rate increases crop competitive ability and thus can enhance herbicide efficacy. However, it is unknown how increasing the seeding rate affects an herbicide’s efficacy. The objective of this study was to examine the interaction between increasing seeding rate and herbicide dose to control weeds. To meet this objective, the herbicide fluthiacet-methyl was applied to field-grown lentil, with Indian mustard, a proxy for wild mustard, used as a model weed. The experiment was a factorial design with four lentil seeding rates and seven herbicide rates. Overall the herbicide dose response was altered by changing lentil seeding rate. Increasing lentil seeding rate decreased the weed biomass production when herbicides were not applied. In two of the four site-years, increasing lentil seeding rate lowered the herbicide ED50, the dose required to result in a 50% reduction in weed biomass. Increasing the crop seeding rate altered the dose response to provide greater weed control at lower herbicide rates compared with normal crop seeding rates. Increased seeding rates also resulted in higher and more stable crop seed yields across a wider range of herbicide dosages. These results suggest that dose–response models can be used to evaluate the efficacy of other weed management practices that can interact with herbicide performance.

Seeding rate, herbicide timing and competitive hybrids contribute to integrated weed management in canola (Brassica napus)

2003 ◽  
Vol 83 (2) ◽  
pp. 433-440 ◽  
Author(s):  
K. N. Harker ◽  
G. W. Clayton ◽  
R. E. Blackshaw ◽  
J. T. O’Donovan ◽  
F. C. Stevenson
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Weed Suppression ◽  
Integrated Weed Management ◽  
Seeding Rate ◽  
Yield Increase ◽  
Net Returns ◽  
Herbicide Timing ◽  
Crop Health ◽  
Weed Removal

Implementing a favourable agronomic practice often enhances canola production. Combining several optimal practices may further increase production, and, given greater crop health and competitiveness, could also improve weed control. A field experiment was conducted at Lacombe and Lethbridge, Alberta, from 1998 to 2000, to determine the optimal combination of glufosinate-tolerant cultivar (hybrid InVigor 2153 or open-pollinated Exceed), crop seeding rate (100, 150, or 200 seeds m-2) and time of weed removal (two-, four-, or six-leaf stage of canola) for canola yield and weed suppression. At equal targeted seeding rates, the hybrid cultivar had greater seedling density (8 plants m-2 higher) and seed yield (22% higher) when compared with the open-pollinated cultivar. Combining the better cultivar with the highest seeding rate, and the earliest time of weed removal led to a 41% yield increase compared with the combination of the weaker cultivar, the lowest seeding rate and the latest time of weed removal. The same optimal factor levels also favoured higher levels of weed control and lower weed biomass variability. Managing these factors at optimal levels may help increase net returns, reduce herbicide dependence and favour the adoption of more integrated weed management systems. Key words: Crop health, direct seeding, glufosinate, integrated weed management, weed population variability

scholarly journals Herbicide-resistant crops in resistant weed management : An industrial perspective

2005 ◽  
Vol 75 (4) ◽  
pp. 79-84 ◽  
Author(s):  
D. Shaner
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Wild Species ◽  
Integrated Weed Management ◽  
Herbicide Resistant ◽  
Resistant Varieties ◽  
Selection Of

Some of the first products of biotechnology to reach the marketplace have been herbicide-resistant crops. Industry sees the development of herbicide-resistant varieties as a way to increase the availability of proven herbicides for a broader range of crops. However, the development of herbicide- resistant crops requires special attention to potential environmental questions such as herbicide usage, selection of resistant weed biotypes and spread of resistance from the resistant crop to wild species. Industry is actively addressing these concerns during the process of development. Proper development and use of herbicide-resistant crops in integrated weed management programs will provide farmers with increased flexibility, efficiency, and decreased cost in their weed control practices without increasing the risk of herbicide-resistant weeds. Furthermore, herbicide-resistant crops should prove to be valuable tools in managing herbicide- resistant weeds.

scholarly journals Weed Management in Cranberries: A Historical Perspective and a Look to the Future

Agriculture ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 138 ◽  
Author(s):  
Hilary Sandler
Keyword(s):  
Weed Control ◽  
Precision Agriculture ◽  
Weed Management ◽  
Management Practices ◽  
Integrated Weed Management ◽  
Unmanned Aerial Systems ◽  
Early 19Th Century ◽  
Research Areas ◽  
Hand Weeding ◽  
The Impact

Integrated weed management (IWM) has been part of cranberry cultivation since its inception in the early 19th century. Proper site and cultivar selection, good drainage, rapid vine establishment, and hand weeding are as important now for successful weed management as when the industry first started. In 1940, Extension publications listed eight herbicides (e.g., petroleum-based products, inorganic salts and sulfates) for weed control. Currently, 18 herbicides representing 11 different modes of action are registered for use on cranberries. Nonchemical methods, such as hand weeding, sanding, flooding, and proper fertilization, remain integral for managing weed populations; new tactics such as flame cultivation have been added to the toolbox. Priority ratings have been developed to aid in weed management planning. Despite many efforts, biological control of weeds remains elusive on the commercial scale. Evaluation of new herbicides, unmanned aerial systems (UAS), image analysis, and precision agriculture technology; investigation of other management practices for weeds and their natural enemies; utilization of computational decision making and Big Data; and determination of the impact of climate change are research areas whose results will translate into new use recommendations for the weed control of cranberry.

scholarly journals Reducing the Risks of Herbicide Resistance: Best Management Practices and Recommendations

Weed Science ◽  
2012 ◽  
Vol 60 (SP1) ◽  
pp. 31-62 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Sarah M. Ward ◽  
David R. Shaw ◽  
Rick S. Llewellyn ◽  
Robert L. Nichols ◽  
...  
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Best Management Practices ◽  
Weed Management ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Herbicide Resistant ◽  
Economic Thresholds ◽  
Soil Seedbank

Herbicides are the foundation of weed control in commercial crop-production systems. However, herbicide-resistant (HR) weed populations are evolving rapidly as a natural response to selection pressure imposed by modern agricultural management activities. Mitigating the evolution of herbicide resistance depends on reducing selection through diversification of weed control techniques, minimizing the spread of resistance genes and genotypes via pollen or propagule dispersal, and eliminating additions of weed seed to the soil seedbank. Effective deployment of such a multifaceted approach will require shifting from the current concept of basing weed management on single-year economic thresholds.

Integrated Weed Management Using Planting Pattern, Cultivar, and Herbicide in Dry-Seeded Rice in Northwest India

Weed Science ◽  
2014 ◽  
Vol 62 (2) ◽  
pp. 350-359 ◽  
Author(s):  
Gulshan Mahajan ◽  
Vikas Poonia ◽  
Bhagirath S. Chauhan
Keyword(s):  
Grain Yield ◽  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Weed Suppression ◽  
Integrated Weed Management ◽  
Rice Grain ◽  
Planting Pattern ◽  
Weed Biomass ◽  
Northwest India

Field experiments were conducted in Punjab, India, in 2011 and 2012 to study the integrated effect of planting pattern [uniform rows (20-cm spacing) and paired rows (15-, 25-, and 15-cm spacing)], cultivars (PR-115 and IET-21214), and weed control treatments (nontreated control, pendimethalin 750 g ai ha−1, bispyribac-sodium 25 g ai ha−1, and pendimethalin 750 g ha−1 followed by bispyribac-sodium 25 g ha−1) on weed suppression and rice grain yield in dry-seeded rice. In the nontreated control, IET-21214 had higher grain yield than PR-115 in both planting patterns. However, such differences were not observed within the herbicide treatment. IET-21214 in paired rows, even in nontreated control, provided grain yield (4.7 t ha−1) similar to that in uniform rows coupled with the sole application of pendimethalin (4.3 t ha−1) and bispyribac-sodium (5.0 t ha−1). In uniform rows, sequential application of pendimethalin (PRE) and bispyribac-sodium (POST) provided the highest grain yield among all the weed control treatments and this treatment produced grain yield of 5.9 and 6.1 t ha−1 for PR-115 and IET-21214, respectively. Similarly, in paired rows, PR-115 in paired rows treated with sequential application of pendimethalin and bispyribac-sodium had highest grain yield (6.1 t ha−1) among all the weed control treatments. However, IET-21214 with the sole application of bispyribac-sodium produced grain yield similar to the sequential application of pendimethalin and bispyribac-sodium. At 30 days after sowing, PR-115 in paired rows coupled with pendimethalin application accrued weed biomass (10.7 g m−2) similar to the sequential application of pendimethalin and bispyribac-sodium coupled with uniform rows (8.1 g m−2). Similarly, IET-21214 with bispyribac-sodium application provided weed control similar to the sequential application of pendimethalin and bispyribac-sodium. Our study implied that grain yield of some cultivars could be improved by exploring their competitiveness through paired-row planting patterns with less use of herbicides.

scholarly journals Novel sensor-based method (quick test) for the in-season rapid evaluation of herbicide efficacy under real field conditions in durum wheat

Weed Science ◽  
2021 ◽  
Vol 69 (2) ◽  
pp. 147-160
Author(s):  
Ilias Travlos ◽  
Anastasia Tsekoura ◽  
Nikolaos Antonopoulos ◽  
Panagiotis Kanatas ◽  
Ioannis Gazoulis
Keyword(s):  
Durum Wheat ◽  
Weed Management ◽  
Vegetation Index ◽  
Management Practices ◽  
Climatic Conditions ◽  
Integrated Weed Management ◽  
Real Field ◽  
Herbicide Application ◽  
Avena Sterilis ◽  
Herbicide Resistant

AbstractOptimum herbicide use is a key factor affecting the success of any integrated weed management strategy. The main objective of the current study was to implement a method based on spectrometer measurements for the in situ evaluation of herbicide efficacy and the detection of potentially herbicide-resistant weeds. Field trials were conducted in Greece between 2018 and 2020 in several durum wheat fields (Triticum durum Desf.). In all trials, the overall effect of herbicide application on the recorded Normalized Difference Vegetation Index (NDVI) values (at 1 and 2 wk after treatment [WAT]) was significant (P ≤ 0.001). For the majority of the surveyed fields, low NDVI values were recorded after 2,4-D application and a mixture of clopyralid + florasulam from 1 WAT, suggesting their increased efficacy. In several cases, the application of pyroxsulam + florasulam resulted in significant NDVI reductions at 2 WAT. As observed at the end of the growing seasons, the herbicides that reduced NDVI resulted in lower weed biomass. Strong correlations were observed between weed aboveground biomass and NDVI (2 WAT). In particular, R2 values were 0.8234 to 0.8649, 0.8453, 0.8595, 0.8149, and 0.8925 for the Aliartos, Thiva, Domokos, Larissa, and Orestiada fields, respectively. The overall effects of herbicide application on wheat grain yield were also significant (P ≤ 0.001). Pot experiments confirmed that the high NDVI values in some cases could be attributed to the presence of herbicide-resistant weeds. For instance, the resistance indices of two accessions of catchweed bedstraw (Galium aparine L.) to mesosulfuron-methyl + iodosulfuron-methyl-sodium ranged between 9.7 and 13.2, whereas one sterile oat [Avena sterilis L. ssp. ludoviciana (Durieu) Gillet & Magne] accession was 8.8 times more resistant to fenoxaprop-p-ethyl than a susceptible one. The present study is targeted at making a significant contribution toward establishing cause–effect relationships and presenting a useful tool for developing more effective weed management practices in more arable crops and under different soil and climatic conditions.

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