scholarly journals Kochia (Bassia Scoparia) Growth and Fecundity As Influenced By Crop Competition and Weed Density

2022 ◽  
Author(s):  
Charlemagne Ajoc Lim ◽  
Alan T. Dyer ◽  
Prashant Jha
Keyword(s):  
Sugar Beet ◽  
Seed Production ◽  
Great Plains ◽  
Crop Production ◽  
Production Systems ◽  
Competitive Effects ◽  
Herbicide Resistant ◽  
The North ◽  
Biomass Plant ◽  
Delayed Flowering

Abstract Kochia [Bassia scoparia (L.) A. J. Scott] represents one the most troublesome weeds in crop production systems in the North American Great Plains. The development of herbicide-resistant B. scoparia populations further exacerbated this problem. More ecologically driven approaches to its control are necessary. This study examined the competitive effects of four crops (sugar beet, soybean, barley, and corn) in combination with B. scoparia densities (3, 13, 24, 47, 94, and 188 plants m-2) on B. scoparia development and seed production across 2 years. Corn and barley had the greatest impact on B. scoparia growth and fecundity. B. scoparia biomass was 87 and 82% lower and seed production was 98 and 96% lower (p<0.001) in corn and barley, respectively, relative to fallow. Corn had greatest effect in reducing B. scoparia biomass and seed production. Barley had greatest effect in delaying B. scoparia flowering which occurred 113 days after B. scoparia emergence (p<0.001). Soybean and sugar beet had the least effect reducing B. scoparia biomass by 70 and 65% and seed production by 84 and 80% (p<0.001), respectively, relative to fallow. Increasing B. scoparia densities resulted in reductions in B. scoparia width, number of primary branches, biomass plant-1, and seeds plant-1 but increased B. scoparia height, biomass m-2, and seeds m-2 (p<0.001) under all cropping treatments except corn. Barley represents the greatest opportunity to impact B. scoparia through reduced fecundity and delayed flowering, with the latter providing a window of opportunity for post-harvest control. The effects observed here were isolated from differences in herbicide practices that are associated with each of these crops, differences that have a dramatic effect on B. scoparia in their own right.

Effects of cereal rye seeding rate on waterhemp (Amaranthus tuberculatus) emergence and soybean growth and yield

2021 ◽  
pp. 1-25
Author(s):  
Mandy Bish ◽  
Brian Dintelmann ◽  
Eric Oseland ◽  
Jacob Vaughn ◽  
Kevin Bradley
Keyword(s):  
Crop Production ◽  
Production Systems ◽  
Soil Seed Bank ◽  
Linear Regression Analysis ◽  
Growth And Yield ◽  
Seeding Rate ◽  
Early Season ◽  
Cereal Rye ◽  
Herbicide Resistant ◽  
Growing Seasons

Abstract The evolution of herbicide-resistant weeds has resulted in the necessity to integrate non-chemical control methods with chemicals for effective management in crop production systems. In soybean, control of the pigweed species, particularly herbicide-resistant waterhemp and Palmer amaranth, have become predominant concerns. Cereal rye planted as a winter cover crop can effectively suppress early-season weed emergence in soybean, including waterhemp, when planted at a rate of 123 kg ha−1. The objectives of this study were to determine the effects of different cereal rye seeding rates (0, 34, 56, 79, 110, and 123 kg ha−1) on early-season waterhemp suppression and soybean growth and yield. Soybean was planted into fall-seeded cereal rye, which was terminated within four days of soybean planting. The experiment was conducted over the 2018, 2019, and 2020 growing seasons in Columbia, Missouri. Effects of cereal rye on early-season waterhemp suppression varied by year and were most consistent at 56 kg ha−1 or higher seeding rates. Linear regression analysis of cereal rye biomass, height, or stand at soybean planting showed inverse relationships with waterhemp emergence. No adverse effects to soybean growth or yield were observed at any of the cereal rye seeding rates relative to plots that lacked cereal rye cover. Result differences among the years suggest that the successfulness of cereal rye on suppression of early-season waterhemp emergence is likely influenced by the amount of waterhemp seed present in the soil seed bank.

scholarly journals Effect of EPSPS Gene Copy Number and Glyphosate Selection on Fitness of Glyphosate-Resistant Bassia Scoparia in The Field

2021 ◽  
Author(s):  
Charlemagne Ajoc Lim ◽  
Prashant Jha ◽  
Vipan Kumar ◽  
Alan T. Dyer
Keyword(s):  
Sugar Beet ◽  
Seed Production ◽  
Great Plains ◽  
Copy Number ◽  
Gene Copy Number ◽  
Reproductive Traits ◽  
Gene Copy ◽  
Epsps Gene ◽  
Gene Copies

Abstract The widespread evolution of glyphosate-resistant (GR) Bassia scoparia in the U.S. Great Plains poses a serious threat to the long-term sustainability of GR sugar beet. Glyphosate resistance in B. scoparia is due to an increase in the EPSPS (5-enolpyruvyl-shikimate-3-phosphate) gene copy number. The variation in EPSPS gene copies among individuals from within a single GR B. scoparia population indicated a differential response to glyphosate selection. We tested the hypothesis of reduced GR B. scoparia fitness (reproductive traits) to increasing glyphosate rates (applied as single or sequential applications) potentially experienced within a GR sugar beet field. The variation in EPSPS gene copy number and total glyphosate rate (single or sequential applications) did not influence any of the reproductive traits of GR B. scoparia, except seed production. Sequential applications of glyphosate with a total rate of 2,214 g ae ha− 1 or higher prevented seed production in B. scoparia plants with 2–4 (low levels of resistance) and 5–6 (moderate levels of resistance) EPSPS gene copies. Timely sequential applications of glyphosate (full recommended rates) can potentially slow down the evolution of GR B. scoparia with low to moderate levels of resistance (2–6 EPSPS gene copies), but any survivors (highly-resistant individuals with ≥ 8 EPSPS gene copies) need to be mechanically removed before flowering from GR sugar beet fields. This research warrants the need to adopt ecologically based, multi-tactic strategies to reduce exposure of B. scoparia to glyphosate in GR sugar beet.

scholarly journals Diverse Approaches to Herbicide-Resistant Weed Management

Weed Science ◽  
2016 ◽  
Vol 64 (SP1) ◽  
pp. 570-584 ◽  
Author(s):  
Micheal D. K. Owen
Keyword(s):  
Weed Management ◽  
Crop Production ◽  
Production Systems ◽  
Cost Effective ◽  
Developed Countries ◽  
Weed Species ◽  
Herbicide Resistant ◽  
Cost Effective Method ◽  
Evolution Of Resistance ◽  
Complexity Cost

Herbicides have been the principal means of weed control in developed countries for approximately 50 yr because they are the most cost-effective method. Such general use of herbicides has resulted in weed resistance to herbicides, which continues to be a growing problem. Within the past decade, the evolution of resistance to the once-dominant herbicide glyphosate has resulted in major concerns about the future ability to control weeds in many crop systems. Moreover, many weed species have evolved resistance to multiple mechanisms of herbicide action. Given the dearth of new herbicides with novel mechanisms of action, it appears inevitable that weed management programs will need to be supplemented by the use of tactics other than herbicides. However, the inclusion of more diversity for weed management also introduces complexity, cost, and time constraints to current crop production systems. This paper describes broadly the considerations, opportunities, and constraints of diverse weed management tactics to address the burgeoning problems with herbicide resistance.

Camelina sativa as a fallow replacement crop in wheat-based crop production systems in the US Great Plains

2018 ◽  
Vol 111 ◽  
pp. 22-29 ◽  
Author(s):  
Augustine K. Obour ◽  
Chengci Chen ◽  
Henry Y. Sintim ◽  
Kent McVay ◽  
Peggy Lamb ◽  
...  
Keyword(s):  
Great Plains ◽  
Crop Production ◽  
Production Systems ◽  
Camelina Sativa ◽  
The Us ◽  
Us Great Plains

Effect of Late-Season Herbicide Applications on Inflorescence and Seed Production of Glyphosate-Resistant Giant Ragweed (Ambrosia trifida)

2017 ◽  
Vol 32 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Zahoor A. Ganie ◽  
Simranpreet Kaur ◽  
Prashant Jha ◽  
Vipan Kumar ◽  
Amit J. Jhala
Keyword(s):  
Seed Production ◽  
Crop Production ◽  
Production Systems ◽  
Integrated Management ◽  
Acetolactate Synthase ◽  
The United States ◽  
Weed Species ◽  
Eastern Canada ◽  
Late Season ◽  
Giant Ragweed

Giant ragweed is one of the most competitive annual broadleaf weeds in corn and soybean crop production systems in the United States and eastern Canada. Management of giant ragweed has become difficult due to the evolution of resistance to glyphosate and/or acetolactate synthase (ALS)-inhibitor herbicides and giant ragweed’s ability to emerge late in the season, specifically in the eastern Corn Belt. Late-season herbicide application may reduce seed production of weed species; however, information is not available about late-season herbicide applications on giant ragweed seed production. The objective of this study was to evaluate the effect of single or sequential late-season applications of 2,4-D, dicamba, glyphosate, and glufosinate on inflorescence injury and seed production of glyphosate-resistant (GR) giant ragweed under greenhouse and field conditions (bare ground study). Single and sequential applications of glufosinate resulted in as much as 59 and 60% injury to giant ragweed inflorescence and as much as 78 and 75% reduction in seed production, respectively, under field and greenhouse conditions. In contrast, single or sequential applications of 2,4-D or dicamba resulted in ≥ 96% inflorescence injury and reduction in seed production in the field as well as in greenhouse studies. The results indicated that 2,4-D or dicamba are effective options for reducing seed production of glyphosate-resistant giant ragweed even if applied late in the season. Targeting weed seed production to decrease the soil seedbank will potentially be an effective strategy for an integrated management of GR giant ragweed.

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.

High Levels of Adoption Indicate That Harvest Weed Seed Control Is Now an Established Weed Control Practice in Australian Cropping

2017 ◽  
Vol 31 (3) ◽  
pp. 341-347 ◽  
Author(s):  
Michael Walsh ◽  
Jackie Ouzman ◽  
Peter Newman ◽  
Stephen Powles ◽  
Rick Llewellyn
Keyword(s):  
Weed Control ◽  
Seed Production ◽  
Crop Production ◽  
Production Systems ◽  
The Other ◽  
Weed Seed ◽  
Control Practice ◽  
Direct System ◽  
High Level ◽  
Very High

HWSC systems that target weed seed production during harvest have been in use in Australian crop production systems for over 30 years. Until recently, though, grower adoption of these systems has been relatively low. It is now apparent with the introduction of a range of new weed seed targeting systems that there is renewed grower interest in the use of this approach to weed control. With the aim of determining the current adoption and use of HWSC systems, 600 crop producers from throughout Australia’s cropping regions were interviewed on their adoption and use of these systems. This survey established that 43% of Australian growers are now routinely using HWSC to target weed seed production during grain harvest. The adoption of narrow-windrow burning (30%) was considerably greater than the other currently available techniques of chaff tramlining (7%), chaff carts (3%), bale-direct system (3%), and the Harrington Seed Destructor (HSD) (<1%). When growers were asked about their future use of these systems 82% indicated that they would be using some form of HWSC within five years. Grower preferences for future HWSC use were primarily for either narrow-windrow burning (42%) or the HSD (29%). This very high level of current and potential HWSC adoption signifies that HWSC is now considered an established weed control practice by Australian growers.

Distribution of Herbicide-Resistant Giant Ragweed (Ambrosia trifida) in Indiana and Characterization of Distinct Glyphosate-Resistant Biotypes

Weed Science ◽  
2017 ◽  
Vol 65 (6) ◽  
pp. 699-709 ◽  
Author(s):  
Nick T. Harre ◽  
Haozhen Nie ◽  
Renae R. Robertson ◽  
William G. Johnson ◽  
Stephen C. Weller ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Crop Production ◽  
Production Systems ◽  
Acetolactate Synthase ◽  
Glyphosate Resistance ◽  
Rapid Response ◽  
Herbicide Resistant ◽  
Crop Fields ◽  
Pam Fluorometer ◽  
Giant Ragweed

Giant ragweed is a highly competitive weed that continually threatens crop production systems due to evolved resistance to acetolactate synthase–inhibiting herbicides (ALS-R) and glyphosate (GR). Two biotypes of GR giant ragweed exist and are differentiated by their response to glyphosate, termed here as rapid response (RR) and non–rapid response (NRR). A comparison of data from surveys of Indiana crop fields done in 2006 and 2014 showed that GR giant ragweed has spread from 15% to 39% of Indiana counties and the NRR biotype is the most prevalent. A TaqMan®single-nucleotide polymorphism genotyping assay was developed to identify ALS-R populations and revealed 47% of GR populations to be ALS-R as well. The magnitude of glyphosate resistance for NRR populations was 4.6 and 5.9 based on GR50and LD50estimates, respectively. For RR populations, these values were 7.8 to 9.2 for GR50estimates and 19.3 to 22.3 for LD50estimates. A novel use of the Imaging-PAM fluorometer was developed to discriminate RR plants by assessing photosystem II quantum yield across the entire leaf surface. H2O2generation in leaves of glyphosate-treated plants was also measured by 3,3′-diaminobenzidine staining and quantified using imagery analysis software. Results show photo-oxidative stress of mature leaves is far greater and occurs more rapidly following glyphosate treatment in RR plants compared with NRR and glyphosate-susceptible plants and is positively associated with glyphosate dose. These results suggest that under continued glyphosate selection pressure, the RR biotype may surpass the NRR biotype as the predominant form of GR giant ragweed in Indiana due to a higher level of glyphosate resistance. Moreover, the differential photo-oxidative stress patterns in response to glyphosate provide evidence of different mechanisms of resistance present in RR and NRR biotypes.

scholarly journals Herbicide Resistance: Toward an Understanding of Resistance Development and the Impact of Herbicide-Resistant Crops

Weed Science ◽  
2012 ◽  
Vol 60 (SP1) ◽  
pp. 2-30 ◽  
Author(s):  
William K. Vencill ◽  
Robert L. Nichols ◽  
Theodore M. Webster ◽  
John K. Soteres ◽  
Carol Mallory-Smith ◽  
...  
Keyword(s):  
Crop Production ◽  
Cultural Practices ◽  
Production Systems ◽  
Mechanisms Of Action ◽  
Slight Reduction ◽  
Herbicide Resistant ◽  
Concurrent Use ◽  
High Selection ◽  
Herbicide Use ◽  
The Impact

Development of herbicide-resistant crops has resulted in significant changes to agronomic practices, one of which is the adoption of effective, simple, low-risk, crop-production systems with less dependency on tillage and lower energy requirements. Overall, the changes have had a positive environmental effect by reducing soil erosion, the fuel use for tillage, and the number of herbicides with groundwater advisories as well as a slight reduction in the overall environmental impact quotient of herbicide use. However, herbicides exert a high selection pressure on weed populations, and density and diversity of weed communities change over time in response to herbicides and other control practices imposed on them. Repeated and intensive use of herbicides with the same mechanisms of action (MOA; the mechanism in the plant that the herbicide detrimentally affects so that the plant succumbs to the herbicide; e.g., inhibition of an enzyme that is vital to plant growth or the inability of a plant to metabolize the herbicide before it has done damage) can rapidly select for shifts to tolerant, difficult-to-control weeds and the evolution of herbicide-resistant weeds, especially in the absence of the concurrent use of herbicides with different mechanisms of action or the use of mechanical or cultural practices or both.

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