An assessment of weed flora 14 years after the introduction of glyphosate-tolerant cotton in Australia

2017 ◽  
Vol 68 (8) ◽  
pp. 773 ◽  
Author(s):  
Sudheesh Manalil ◽  
Jeff Werth ◽  
Rod Jackson ◽  
Bhagirath Singh Chauhan ◽  
Christopher Preston
Keyword(s):  
Weed Management ◽  
Management Strategies ◽  
Cost Effective ◽  
Sesbania Cannabina ◽  
Management Options ◽  
South Wales ◽  
Weed Population Dynamics ◽  
Conyza Bonariensis ◽  
Chloris Virgata ◽  
And Shifts

Glyphosate-tolerant (GT) cotton offers a multitude of benefits such as broad-spectrum and cost-effective weed control, simple weed management, and reduced impact on the environment. However, high adoption rates of GT cotton have led to overreliance on glyphosate in weed management and have decreased the use of other herbicide options and non-chemical weed-management strategies, possibly leading to the emergence of many resistant weeds. Previous surveys in 2006 and 2011 in the cotton-growing regions of New South Wales (NSW) and Queensland, Australia, indicated changes in weed populations over the period and increased prevalence of several weeds. These two surveys indicated increased dominance of Conyza bonariensis, Echinochloa colona, and Chloris virgata in these regions. Periodic weed surveys are necessary to assess weed population dynamics and shifts due to overreliance on glyphosate for weed management. A survey was carried out in the cotton-growing regions of NSW and Queensland in 2014–15, covering 135 fields. Survey results indicated the emergence of volunteer GT cotton as the most common weed present across all of the cotton-growing regions, occurring in 85% of fields, followed by E. colona (67% of fields surveyed), and C. bonariensis and Sonchus oleraceus, which were present in 51% of fields. The most prevalent grass weed after E. colona was C. virgata (37%). Broadleaf weeds Ipomoea lonchophylla and Amaranthus mitchellii were present in 40% and 37% of fields, respectively. Regional-level analysis indicated greater prevalence of Sesbania cannabina and Parthenium hysterophorus in Emerald region of Queensland. Lolium rigidum was present in the Griffith and Warren area of NSW during summer, even though it is a winter weed. The results of this study indicate integration of diversified weed-management options and inclusion of both non-chemical and chemical options because many major weeds observed in this study are tolerant to glyphosate and have already evolved resistance to glyphosate.

scholarly journals Effects of Palmer Amaranth (Amaranthus palmeri) Establishment Time and Distance from the Crop Row on Biological and Phenological Characteristics of the Weed: Implications on Soybean Yield

Weed Science ◽  
2019 ◽  
Vol 67 (1) ◽  
pp. 126-135 ◽  
Author(s):  
Nicholas E. Korres ◽  
Jason K. Norsworthy ◽  
Andy Mauromoustakos
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Cropping Systems ◽  
Management Strategies ◽  
Palmer Amaranth ◽  
Yield Reduction ◽  
Amaranthus Palmeri ◽  
Soybean Yield ◽  
Management Measures ◽  
Weed Population Dynamics

AbstractInformation about weed biology and weed population dynamics is critical for the development of efficient weed management programs. A field experiment was conducted in Fayetteville, AR, during 2014 and 2015 to examine the effects of Palmer amaranth (Amaranthus palmeriS. Watson) establishment time in relation to soybean [Glycine max(L.) Merr.] emergence and the effects ofA. palmeridistance from the soybean row on the weed’s height, biomass, seed production, and flowering time and on soybean yield. The establishment time factor, in weeks after crop emergence (WAE), was composed of six treatment levels (0, 1, 2, 4, 6, and 8 WAE), whereas the distance from the crop consisted of three treatment levels (0, 24, and 48 cm). Differences inA. palmeribiomass and seed production averaged across distance from the crop were found at 0 and 1 WAE in both years. Establishment time had a significant effect onA. palmeriseed production through greater biomass production and height increases at earlier dates.Amaranthus palmerithat was established with the crop (0 WAE) overtopped soybean at about 7 and 10 WAE in 2014 and 2015, respectively. Distance from the crop affectedA. palmeriheight, biomass, and seed production. The greater the distance from the crop, the higherA. palmeriheight, biomass, and seed production at 0 and 1 WAE compared with other dates (i.e., 2, 4, 6, and 8 WAE).Amaranthus palmeriestablishment time had a significant impact on soybean yield, but distance from the crop did not. The earlierA. palmeriinterfered with soybean (0 and 1 WAE), the greater the crop yield reduction; after that period no significant yield reductions were recorded compared with the rest of the weed establishment times. Knowledge ofA. palmeriresponse, especially at early stages of its life cycle, is important for designing efficient weed management strategies and cropping systems that can enhance crop competitiveness. Control ofA. palmeriwithin the first week after crop emergence or reduced distance between crop and weed are important factors for an effective implementation of weed management measures againstA. palmeriand reduced soybean yield losses due to weed interference.

scholarly journals Benefits and Limitations of Decision Support Systems (DSS) with a Special Emphasis on Weeds

Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 548 ◽  
Author(s):  
Panagiotis Kanatas ◽  
Ilias S. Travlos ◽  
Ioannis Gazoulis ◽  
Alexandros Tataridas ◽  
Anastasia Tsekoura ◽  
...  
Keyword(s):  
Decision Support ◽  
Decision Support Systems ◽  
Weed Management ◽  
Crop Production ◽  
Support Systems ◽  
Management Strategies ◽  
Farming Systems ◽  
Climatic Conditions ◽  
Management Options ◽  
The Right

Decision support systems (DSS) have the potential to support farmers to make the right decisions in weed management. DSSs can select the appropriate herbicides for a given field and suggest the minimum dose rates for an herbicide application that can result in optimum weed control. Given that the adoption of DSSs may lead to decreased herbicide inputs in crop production, their potential for creating eco-friendly and profitable weed management strategies is obvious and desirable for the re-designing of farming systems on a more sustainable basis. Nevertheless, it is difficult to stimulate farmers to use DSSs as it has been noticed that farmers have different expectations of decision-making tools depending on their farming styles and usual practices. The function of DSSs requires accurate assessments of weeds within a field as input data; however, capturing the data can be problematic. The development of future DSSs should target to enhance weed management tactics which are less reliant on herbicides. DSSs should also provide information regarding weed seedbank dynamics in the soil in order to suggest management options not only within a single period but also in a rotational view. More aspects ought to be taken into account and further research is needed in order to optimize the practical use of DSSs for supporting farmers regarding weed management issues in various crops and under various soil and climatic conditions.

Modeling Glyphosate Resistance Management Strategies for Palmer Amaranth (Amaranthus palmeri) in Cotton

2011 ◽  
Vol 25 (3) ◽  
pp. 335-343 ◽  
Author(s):  
Paul Neve ◽  
Jason K. Norsworthy ◽  
Kenneth L. Smith ◽  
Ian A. Zelaya
Keyword(s):  
Weed Management ◽  
Management Strategies ◽  
Resistance Management ◽  
Glyphosate Resistance ◽  
Palmer Amaranth ◽  
Case Scenario ◽  
Management Options ◽  
Worst Case ◽  
Resistance Risk ◽  
Resistance Evolution

A simulation model is used to explore management options to mitigate risks of glyphosate resistance evolution in Palmer amaranth in glyphosate-resistant cotton in the southern United States. Our first analysis compares risks of glyphosate resistance evolution for seven weed-management strategies in continuous glyphosate-resistant cotton monoculture. In the “worst-case scenario” with five applications of glyphosate each year and no other herbicides applied, evolution of glyphosate resistance was predicted in 74% of simulated populations. In other strategies, glyphosate was applied with various combinations of preplant, PRE, and POST residual herbicides. The most effective strategy included four glyphosate applications with a preplant fomesafen application, and POST tank mixtures of glyphosate plusS-metolachlor followed by glyphosate plus flumioxazin. This strategy reduced the resistance risk to 12% of populations. A second series of simulations compared strategies where glyphosate-resistant cotton was grown in one-to-one rotations with corn or cotton with other herbicide resistance traits. In general, crop rotation reduced risks of resistance by approximately 50% and delayed the evolution of resistance by 2 to 3 yr. These analyses demonstrate that risks of glyphosate resistance evolution in Palmer amaranth can be reduced by reducing glyphosate use within and among years, controlling populations with diverse herbicide modes of action, and ensuring that population size is kept low. However, no strategy completely eliminated the risk of glyphosate resistance.

scholarly journals Coffee Berry Borer (Hypothenemus hampei), a Global Pest of Coffee: Perspectives from Historical and Recent Invasions, and Future Priorities

Insects ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 882
Author(s):  
Melissa A. Johnson ◽  
Claudia Patricia Ruiz-Diaz ◽  
Nicholas C. Manoukis ◽  
Jose Carlos Verle Rodrigues
Keyword(s):  
Insect Pest ◽  
Management Strategies ◽  
Invasion Biology ◽  
Cost Effective ◽  
Future Research ◽  
Successful Implementation ◽  
Hypothenemus Hampei ◽  
Coffee Berry ◽  
Management Options ◽  
Coffee Berry Borer

Coffee berry borer (Hypothenemus hampei (Ferrari), CBB) has invaded nearly every coffee-producing country in the world, and it is commonly recognized as the most damaging insect pest of coffee. While research has been conducted on this pest in individual coffee-growing regions, new insights may be gained by comparing and contrasting patterns of invasion and response across its global distribution. In this review, we explore the existing literature and focus on common themes in the invasion biology of CBB by examining (1) how it was introduced into each particular region and the response to its invasion, (2) flight activity and infestation patterns, (3) economic impacts, and (4) management strategies. We highlight research conducted over the last ten years in Hawaii as a case study for the development and implementation of an effective integrated pest management (IPM) program for CBB, and also discuss biosecurity issues contributing to incursion and establishment. Potential areas for future research in each of the five major components of CBB IPM (monitoring and sampling, cultural, biological, chemical, and physical controls) are also presented. Finally, we emphasize that outreach efforts are crucial to the successful implementation of CBB IPM programs. Future research programs should strive to include coffee growers as much as possible to ensure that management options are feasible and cost-effective.

Effectiveness of glufosinate, dicamba, and clethodim on glyphosate-resistant and susceptible populations of five key weeds in Australian cotton systems

2021 ◽  
pp. 1-20
Author(s):  
Jeff Werth ◽  
David Thormby ◽  
Michelle Keenan ◽  
James Hereward ◽  
Bhagirath Singh Chauhan
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Resistance Management ◽  
Sonchus Oleraceus ◽  
Conyza Bonariensis ◽  
Resistant Population ◽  
Susceptible Populations ◽  
Chloris Virgata ◽  
Effective Treatments

XtendFlexTM cotton with resistance to glyphosate, glufosinate and dicamba may become available in Australia. Resistance to these herbicides enables two additional modes of action to be applied in crop. The double knock strategy, typically glyphosate followed by paraquat, has been a successful tactic for control of glyphosate-resistant in fallow situations in Australia. Glufosinate is a contact herbicide, and may be useful as the second herbicide in a double knock for use in XtendFlexTM cotton crops. We tested the effectiveness of glufosinate applied at intervals of 1, 3, 7, and 10 d after initial applications of glyphosate, dicamba, clethodim and glyphosate mixtures with dicamba or clethodim on glyphosate-resistant and susceptible populations of Conyza bonariensis, Sonchus oleraceus, Chloris virgata, Chloris truncata and Echinochloa colona. Effective treatments for Conyza bonariensis with 100% control were dicamba and glyphosate+dicamba followed by glufosinate independent of the interval between applications. Sonchus oleraceus was effectively controlled in Experiment 1 by all treatments. However, in Experiment 2 effective treatments were dicamba and glyphosate+dicamba followed by glufosinate (99.3 – 100% control). Timing of the follow-up glufosinate did not affect the control achieved. Consistent control of Chloris virgata was achieved with glyphosate, clethodim or glyphosate+clethodim followed by glufosinate at 7 and 10 d intervals (99.7 – 100% control). Control of Chloris truncata was inconsistent. The best treatment for C. truncata was glyphosate+clethodim followed by glufosinate 10 d later (99.8 – 100% control). Echinochloa colona was effectively controlled with all treatments except for glyphosate on the glyphosate-resistant population. Additional in-crop use of glufosinate and dicamba should be beneficial for weed management in XtendFlexTM cotton crops, when utilising the double knock tactic with glufosinate. For effective herbicide resistance management, it is important that these herbicides be used in addition to, rather than substitution for, existing weed management tactics.

scholarly journals Defining Integrated Weed Management: A Novel Conceptual Framework for Models

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 747
Author(s):  
Jonathan Storkey ◽  
Joseph Helps ◽  
Richard Hull ◽  
Alice E. Milne ◽  
Helen Metcalfe
Keyword(s):  
Population Dynamics ◽  
Conceptual Framework ◽  
Herbicide Resistance ◽  
Weed Management ◽  
Integrated Weed Management ◽  
Management Options ◽  
Weed Population ◽  
Weed Population Dynamics ◽  
Population Dynamics Models ◽  
Dynamics Models

Weed population dynamics models are an important tool for predicting the outcome of alternative Integrated Weed Management (IWM) scenarios. The growing problem of herbicide resistance has increased the urgency for these tools in the design of sustainable IWM solutions. We developed a conceptual framework for defining IWM as a standardised input template to allow output from different models to be compared and to design IWM scenarios. The framework could also be used as a quantitative metric to determine whether more diverse systems are more sustainable and less vulnerable to herbicide resistance using empirical data. Using the logic of object-oriented programming, we defined four classes of weed management options based on the stage in the weed life cycle that they impact and processes that mediate their effects. Objects in the same class share a common set of properties that determine their behaviour in weed population dynamics models. Any weed control “event” in a system is associated with an object, meaning alternative management scenarios can be built by systematically adding events to a model either to compare existing systems or design novel approaches. Our framework is designed to be generic, allowing IWM systems from different cropping systems and countries to be compared.

scholarly journals Changes in weed species since the introduction of glyphosate-resistant cotton

2013 ◽  
Vol 64 (8) ◽  
pp. 791 ◽  
Author(s):  
Jeff Werth ◽  
Luke Boucher ◽  
David Thornby ◽  
Steve Walker ◽  
Graham Charles
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Weed Species ◽  
Sonchus Oleraceus ◽  
Cropping Season ◽  
Conyza Bonariensis ◽  
Major Species ◽  
Chloris Virgata ◽  
A Minor ◽  
Over The Top

Weed management practices in cotton systems that were based on frequent cultivation, residual herbicides, and some post-emergent herbicides have changed. The ability to use glyphosate as a knockdown before planting, in shielded sprayers, and now over-the-top in glyphosate-tolerant cotton has seen a significant reduction in the use of residual herbicides and cultivation. Glyphosate is now the dominant herbicide in both crop and fallow. This reliance increases the risk of shifts to glyphosate-tolerant species and the evolution of glyphosate-resistant weeds. Four surveys were undertaken in the 2008–09 and 2010–11 seasons. Surveys were conducted at the start of the summer cropping season (November–December) and at the end of the same season (March–April). Fifty fields previously surveyed in irrigated and non-irrigated cotton systems were re-surveyed. A major species shift towards Conyza bonariensis was observed. There was also a minor increase in the prevalence of Sonchus oleraceus. Several species were still present at the end of the season, indicating either poor control and/or late-season germinations. These included C. bonariensis, S. oleraceus, Hibiscus verdcourtii and Hibiscus tridactylites, Echinochloa colona, Convolvulus sp., Ipomea lonchophylla, Chamaesyce drummondii, Cullen sp., Amaranthus macrocarpus, and Chloris virgata. These species, with the exception of E. colona, H. verdcourtii, and H. tridactylites, have tolerance to glyphosate and therefore are likely candidates to either remain or increase in dominance in a glyphosate-based system.

scholarly journals IWMPRAISE – An EU Horizon 2020 Project Providing Integrated Weed Management Solutions to European Farmers

2020 ◽  
Vol 31 (4) ◽  
pp. 152-159
Author(s):  
Per Kudsk ◽  
Mette Sønderskov ◽  
Ludovic Bonin ◽  
Jose L. Gonzalez-Andujar ◽  
Jens Erik Jensen ◽  
...  
Keyword(s):  
Weed Management ◽  
Negative Impact ◽  
Management Strategies ◽  
Farming Systems ◽  
European Countries ◽  
Integrated Weed Management ◽  
Conventional Farming ◽  
Management Options ◽  
Horizon 2020 ◽  
Sites Of Action

IWMPRAISE is the first EU Framework Research project focusing solely on weed management. Thirty-eight partners in eight European countries are working together on developing integrated weed management strategies for agricultural and horticultural crops. Per Kudsk, the coordinator of IWMPRAISE, and the work package leaders present the project, the on-going studies and some of the early outputs. Weeds are ubiquitous and cause substantial yield losses across all arable and horticultural systems. Currently, the reliance on herbicides is very high in conventional farming systems and in many European countries herbicides are the single most used group of pesticides (https://appsso.eurostat.ec.europa.eu/nui/show.do?dataset=aei_fm_salpest09&lang=en). There are several reasons for the high herbicide use, such as lack of threshold-based spraying decisions and lack of any single sufficiently effective, readily applicable, cost-effective non-chemical method. Nonetheless, two factors are driving an immediate need to change weed control practices in conventional farming: the rapidly increasing problem of herbicide resistance, exacerbated by the fact that no new herbicide sites of action have been marketed since the early 1980s, and the expectation that many of the currently used herbicides will be withdrawn from the EU market as they do not meet the human and environmental toxicity criteria set out in EU Regulation 1109/2009. In addition to these two immediate concerns, it has also been shown that herbicides have partly been responsible for recent declines in farmland biodiversity and hence a negative impact on the associated ecosystem services. The over-reliance on chemical control of weeds has highlighted the need for Integrated Weed Management (IWM) strategies that combine non-chemical management options that reduce either weed density or competition with the crop.

A regional model of sheep lice to study the effect on lice prevalence and costs for Australian farms using a range of treatment efficacy in combination with other lice control strategies

2017 ◽  
Vol 57 (9) ◽  
pp. 1931
Author(s):  
Peri G. Lucas ◽  
Brian J. Horton ◽  
David Parsons ◽  
Anna L. Carew
Keyword(s):  
Management Practices ◽  
Net Present Value ◽  
Control Strategies ◽  
Management Strategies ◽  
Cost Effective ◽  
Published Data ◽  
Management Options ◽  
Financial Return ◽  
Intervention Level ◽  
Sheep Production

Using a previously developed predictive model, three different management practices were examined in combination with post-shearing chemical treatments for lice, to determine which combinations could provide cost-effective reductions in lice prevalence over a 20-year period. The model included nine sheep production regions across Australia, all of which have different regional flock prevalence of lice and mean numbers of sheep/property. The lice prevalence model simulated the effects of four management options on Australian lice prevalence and on financial return (expressed as net present value) over a 20-year period. Management options modelled in this study were: treatment for eradication, inspection for lice detection, intervention level, and biosecurity of purchased sheep. The costs and benefits of these management options were calculated on the basis of published data or standard industry costs. Combinations of eradication achieved through treatment and biosecurity of purchased sheep provided the greatest modelled reductions in Australian flock lice prevalence at the lowest cost. With current management practices, lice prevalence was estimated as 16.3% of Australian properties infested and lice costs were estimated at 902 cents per sheep over 20 years. The model estimated that with appropriate management, lice prevalence could be reduced to less than 1.5% of properties infested and costs could be halved to 435 cents per sheep over 20 years. With further development, the modelling described herein offers potential guidance for Australian sheep producers in selecting the most effective and cost-efficient combination of management strategies to reduce lice infestation.

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