scholarly journals Advancing Weed Management Strategies Using Metagenomic Techniques

Weed Science ◽  
2013 ◽  
Vol 61 (2) ◽  
pp. 171-184 ◽  
Author(s):  
Jenny Kao-Kniffin ◽  
Sarah M. Carver ◽  
Antonio DiTommaso
Keyword(s):  
Weed Management ◽  
Soil Bacteria ◽  
Control Strategies ◽  
Management Strategies ◽  
Past Research ◽  
Management Research ◽  
Herbicide Resistant ◽  
Culture Independent ◽  
Living Organisms ◽  
Culture Dependent

Global occurrences of herbicide resistant weed populations have increased the demand for development of new herbicides targeting novel mechanisms of action. Metagenomic approaches to natural drug discovery offer potential for isolating weed suppressive compounds from microorganisms. In past research, traditional techniques entailed isolating compounds from living organisms, whereas metagenomic approaches involve extracting fragments of DNA from soil and exploring for compounds of interest produced by the transformed hosts. Several herbicidal compounds have been isolated from soil bacteria through culturing methods and have led to the development of popular herbicides, such as glufosinate. In this review, we discuss the emergence of metagenomic approaches for weed management in the context of natural product discovery using traditional culture-dependent isolation and the more recent culture-independent methods. The same techniques can be used to isolate herbicide resistance genes. Adoption of metagenomic approaches in pest management research can lead to novel control strategies in cropping and landscape systems.

Suppression of Glyphosate-resistant Canada Fleabane (Conyza canadensis) in Corn with Cover Crops Seeded after Wheat Harvest the Previous Year

2018 ◽  
Vol 32 (3) ◽  
pp. 244-250 ◽  
Author(s):  
Taïga B. Cholette ◽  
Nader Soltani ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
Peter H. Sikkema
Keyword(s):  
Cover Crops ◽  
Weed Management ◽  
Cover Crop ◽  
Management Strategies ◽  
Late Summer ◽  
Growing Season ◽  
Integrated Weed Management ◽  
Crop Species ◽  
Herbicide Resistant ◽  
Crimson Clover

AbstractGlyphosate-resistant (GR) and multiple herbicide–resistant (groups 2 and 9) Canada fleabane have been confirmed in 30 and 23 counties in Ontario, respectively. The widespread incidence of herbicide-resistant Canada fleabane highlights the importance of developing integrated weed management strategies. One strategy is to suppress Canada fleabane using cover crops. Seventeen different cover crop monocultures or polycultures were seeded after winter wheat harvest in late summer to determine GR Canada fleabane suppression in corn grown the following growing season. All cover crop treatments seeded after wheat harvest suppressed GR Canada fleabane in corn the following year. At 4 wk after cover crop emergence (WAE), estimated cover crop ground cover ranged from 31% to 68%, a density of 124 to 638 plants m–2, and a range of biomass from 29 to 109 g m–2, depending on cover crop species. All of the cover crop treatments suppressed GR Canada fleabane in corn grown the following growing season from May to September compared to the no cover crop control. Among treatments evaluated, annual ryegrass (ARG), crimson clover (CC)/ARG, oilseed radish (OSR)/CC/ARG, and OSR/CC/cereal rye (CR) were the best treatments for the suppression of GR Canada fleabane in corn. ARG alone or in combination with CC provided the most consistent GR Canada fleabane suppression, density reduction, and biomass reduction in corn. Grain corn yields were not affected by the use of the cover crops evaluated for Canada fleabane suppression.

Genetic Aspects of Herbicide-Resistant Weed Management

1999 ◽  
Vol 13 (3) ◽  
pp. 647-652 ◽  
Author(s):  
Michael J. Christoffers
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Selection Pressure ◽  
Management Strategies ◽  
Resistance Management ◽  
Wild Type ◽  
Frequency Increase ◽  
Specific Nature ◽  
Herbicide Resistant ◽  
Case Basis

Weed populations develop herbicide resistance when they evolve due to selection pressure. Mutations and gene flow contribute to genetic variability and provide resistant alleles. The speed of resistance gene frequency increase is determined by the inheritance of resistance alleles relative to wild-type susceptibility and is influenced by the interaction between gene expression and selection. The goal of herbicide resistance management is to minimize selection pressure while maintaining adequate weed control. However, the specific nature of each herbicide, weed, and resistance combination determines the practices that optimize undesirable selection pressure. Therefore, generalized management strategies should be recommended with caution and must not be mandated without thorough evaluation on a case-by-case basis.

Assessment of crop and weed management strategies prior to introduction of auxin-resistant crops in Brazil

2020 ◽  
pp. 1-11
Author(s):  
Maxwel C. Oliveira ◽  
Anelise Lencina ◽  
André R. Ulguim ◽  
Rodrigo Werle
Keyword(s):  
Cover Crops ◽  
Weed Management ◽  
Management Practices ◽  
Cropping Systems ◽  
Control Strategies ◽  
Management Strategies ◽  
Acetolactate Synthase ◽  
Weed Species ◽  
Research Education ◽  
No Till

Abstract A stakeholder survey was conducted from April through June of 2018 to understand stakeholders’ perceptions and challenges about cropping systems and weed management in Brazil. The dominant crops managed by survey respondents were soybean (73%) and corn (66%). Approximately 75% of survey respondents have grown or managed annual cropping systems with two to three crops per year cultivated in succession. Eighteen percent of respondents manage only irrigated cropping systems, and over 60% of respondents adopt no-till as a standard practice. According to respondents, the top five troublesome weed species in Brazilian cropping systems are horseweed (asthmaweed, Canadian horseweed, and tall fleabane), sourgrass, morningglory, goosegrass, and dayflower (Asiatic dayflower and Benghal dayflower). Among the nine species documented to have evolved resistance to glyphosate in Brazil, horseweed and sourgrass were reported as the most concerning weeds. Other than glyphosate, 31% and 78% of respondents, respectively, manage weeds resistant to acetyl-CoA carboxylase (ACCase) inhibitors and/or acetolactate synthase (ALS) inhibitors. Besides herbicides, 45% of respondents use mechanical, and 75% use cultural (e.g., no-till, crop rotation/succession) weed control strategies. Sixty-one percent of survey respondents adopt cover crops to some extent to suppress weeds and improve soil chemical and physical properties. Nearly 60% of survey respondents intend to adopt the crops that are resistant to dicamba or 2,4-D when available. Results may help practitioners, academics, industry, and policy makers to better understand the bad and the good of current cropping systems and weed management practices adopted in Brazil, and to adjust research, education, technologies priorities, and needs moving forward.

scholarly journals Rice Ecosystem, Allelopathy and Environment – A Review

2013 ◽  
Vol 11 (1) ◽  
pp. 112-121 ◽  
Author(s):  
AB Siddique ◽  
BS Ismail
Keyword(s):  
Weed Management ◽  
Resource Competition ◽  
Management Strategies ◽  
Growth And Yield ◽  
Weed Species ◽  
Herbicide Resistant ◽  
Evolution Of Resistance ◽  
Weed Infestation ◽  
Repeated Use ◽  
Rice Ecosystem

Allelopathy is an important factor which contributes in determining distribution of species and their abundance within communities. Plant-plant interference is the combined effect of allelopathy, resource competition, and many other factors. Weed infestation is a major problem limiting the growth and yield of rice. Synthetic herbicide has been used for over 50 years as the prime source of weed control. The repeated use of herbicides in rice has already led to the evolution of resistance in some weed species. The conventional synthetic herbicides are becoming less effective against the resistant weed biotypes. Due to increase in the number of herbicide-resistant weeds and environmental concerns in the use of synthetic herbicides, allelopathy has been gaining preference as one of the considerable efforts in designing alternative weed management strategies. Modern ecotoxicologists and allelopathy researchers have been trying to identify allelochemicals to use as biodegradable pesticide. Two allelochemicals have been discovered, namely hexanedioic acid dioctyl ester and di-n-octyl phthalate which can be used as biopesticide. However, still there is enough scope to conduct such research that will contribute to protect our environment as well as increase food safety. DOI: http://dx.doi.org/10.3329/agric.v11i1.15251 The Agriculturists 2013; 11(1) 112-121

Analysis of Different Management Strategies for Annual Ryegrass (Lolium rigidum) Based on a Population Dynamic Model

2018 ◽  
Vol 28 (12) ◽  
pp. 1830041 ◽  
Author(s):  
María Belén D’Amico ◽  
Guillermo L. Calandrini ◽  
José L. González-Andujar ◽  
Guillermo R. Chantre
Keyword(s):  
Weed Management ◽  
Control Strategies ◽  
Management Strategies ◽  
Planning Horizon ◽  
Threshold Level ◽  
Effective Control ◽  
Lolium Rigidum ◽  
Weed Species ◽  
Population Dynamic Model ◽  
Seed Bank Dynamics

Weed species present high competitive capacity, rapid adaptability and herbicide resistance, hindering their effective control across worldwide cropping regions. Since field-conducted experiments are very time-consuming and usually expensive, mathematical population-based models are valuable tools to test and develop long-term weed management programs. Within this context, the objective of this paper is to formalize analytically the possible seed bank dynamics of the Lolium rigidum, subjected to different control strategies. The first focus is on studying in detail the effects of integrating constant actions, promoting more environmentally and economically sustainable scenarios. From the same perspective, an alternative to applying time-variant programs is introduced. The proposed control guarantees that the weed population is sufficiently small or, alternatively, is kept below a given economic threshold level in a ten-year planning horizon. Furthermore, an optimization criterion is adopted for distributing necessary efficiency into diverse integrated options. Numerical simulations are included to illustrate the analytical findings.

Seed production and retention at maturity of blackgrass (Alopecurus myosuroides) and silky windgrass (Apera spica-venti) at wheat harvest

Weed Science ◽  
2020 ◽  
Vol 68 (2) ◽  
pp. 151-156 ◽  
Author(s):  
Zahra Bitarafan ◽  
Christian Andreasen
Keyword(s):  
Seed Production ◽  
Weed Management ◽  
Management Strategies ◽  
Reproductive Development ◽  
Integrated Weed Management ◽  
Herbicide Resistant ◽  
Alopecurus Myosuroides ◽  
Soil Seedbank ◽  
Crop Harvest ◽  
Total Seed

AbstractBlackgrass (Alopecurus myosuroides Huds.) and silky windgrass [Apera spica-venti (L.) P. Beauv.] are becoming a significant problem in Europe. Due to the development of herbicide-resistant biotypes and unwanted side effects of herbicides, there is a need for new integrated weed management strategies to control weeds. Therefore, reducing weed infestations by targeting seed production during crop harvest should be considered. In 2017 and 2018, we estimated the fraction of the total seed production of A. myosuroides and A. spica-venti in a field that potentially could be collected by a grain harvester during winter wheat (Triticum aestivum L.) harvest. Twenty plants of each species were surrounded by a porous net before flowering to trap shed seeds during reproductive development. Seeds were collected and counted weekly up until and immediately before wheat harvest, and the ratio of harvestable seeds to shed seeds during the growing season was determined. Alopecurus myosuroides produced on average 953 seeds plant−1 in 2017 and 3,337 seeds plant−1 in 2018. In 2017 and 2018, 29% and 37% of the total A. myosuroides seeds produced, respectively, were retained on plants at maturity. Apera spica-venti produced on average 1,192 seeds plant−1 in 2017 and 5,678 seeds plant−1 in 2018, and retained 53% and 16% of the seeds at harvest, respectively. If a grain harvester potentially collected approximately 30% of the total seed production of the two grass weeds and removed or killed them, it would reduce seed input to the soil seedbank. However, such methods cannot stand alone to reduce weed pressure.

Activity of Florpyrauxifen-benzyl on Fall Panicum (Panicum dichotomiflorumMichx.) and Nealley’s Sprangletop (Leptochloa nealleyiVasey)

2018 ◽  
Vol 32 (5) ◽  
pp. 603-607 ◽  
Author(s):  
Gustavo M. Teló ◽  
Eric P. Webster ◽  
Benjamin M. McKnight ◽  
David C. Blouin ◽  
Samer Y. Rustom
Keyword(s):  
Weed Management ◽  
Baton Rouge ◽  
Management Strategies ◽  
Grass Species ◽  
State University ◽  
University Campus ◽  
Application Timing ◽  
Herbicide Resistant ◽  
Louisiana State University ◽  
Additional Mode

AbstractA glasshouse study was established at Louisiana State University campus in Baton Rouge, LA, to evaluate the control of fall panicum and Nealley’s sprangletop treated with florpyrauxifen-benzyl. Florpyrauxifen was applied at 30 g ai ha–1to each grass species at the three- to four-leaf and one- to two-tiller stages of growth. At 21 d after treatment (DAT), fall panicum control was 91% when treated with florpyrauxifen at the three- to four-leaf stage, and Nealley’s sprangletop control was 78% to 82%, regardless of application timing 21 DAT. Leaf number, tiller number, plant height, and plant fresh weight were reduced when fall panicum and Nealley’s sprangletop were treated with florpyrauxifen. This information can be useful for developing weed management strategies with this herbicide for rice production, and it provides an additional mode of action to help manage and/or delay the development of herbicide-resistant weeds.

Herbicide resistance in the nursery crop production and landscape maintenance industries

2020 ◽  
Vol 34 (3) ◽  
pp. 437-446
Author(s):  
Jeffrey F. Derr ◽  
Joseph C. Neal ◽  
Prasanta C. Bhowmik
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Weed Management ◽  
Crop Production ◽  
Management Strategies ◽  
Educational Process ◽  
Christmas Tree ◽  
Management Tools ◽  
Herbicide Resistant ◽  
Ornamental Species

AbstractWeed management is an important issue for nursery crop and Christmas tree producers, as well as for those maintaining turfgrass or ornamental species in landscape plantings. PRE and POST herbicides are important weed management tools for these industries. Reports of herbicide-resistant weeds increased from fewer than 100 cases in 1985 to nearly 500 cases globally in 2019, including ones found in turfgrass or ornamental systems. The evolution, persistence, and management of herbicide-resistant weeds are an ongoing educational process. We must keep our stakeholders aware of improved weed control technology and provide them information on resistant weeds. A symposium at the 2019 Weed Science Society of America meeting was conducted with presentations and discussions by invited speakers in relation to current research and potential management strategies for resistant weeds in turfgrass, landscape ornamental, and nursery crops. To prepare for the symposium, a survey was prepared for nursery producers and landscapers on the issues of herbicide-resistant weeds and offsite movement of herbicides used to control herbicide-resistant weeds. Overall, most respondents felt herbicide-resistant weeds are a serious problem and most had personally observed herbicide resistance on properties they maintain. Resistance to glyphosate was the herbicide cited by most respondents, followed by resistance to triazine herbicides. Most felt their weed-control costs had increased because of resistant weeds. Approximately 20% of respondents had their operation affected by drift of herbicides from nearby farm fields, with most reporting no damage from spray or vapor drift, but a few reported greater than 50% of the crop damaged.

scholarly journals Integrated weed management strategies for delaying herbicide resistance in wild oats

2005 ◽  
Vol 75 (4) ◽  
pp. 61-70 ◽  
Author(s):  
D.C. Thill ◽  
J.T. O’Donovan ◽  
C.A. Mallory-Smith
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Management Strategies ◽  
Cultural Control ◽  
Integrated System ◽  
Integrated Weed Management ◽  
Herbicide Resistant ◽  
Wild Oats ◽  
External Sources ◽  
Soil Seedbank

Herbicide-resistant biotypes of wild oats (Avena fatua) infest most major cereal producing regions in the western United States and Canada. This paper reviews potential integrated weed management strategies that can be used to prevent or delay selection of herbicide-resistant wild oats plants. An integrated wild oats management strategy to delay or prevent the development of herbicide resistance should be based on preventing the movement of wild oats seed into the soil. Two ways to achieve this are by preventing the immigration of seed into the field from external sources, and by reducing or eliminating seed production by wild oats already in the field. It is becoming increasingly clear that reliance on continuous herbicide useas the sole means of weed control will fail to eliminate wild oats and other weed seed from the soil seedbank. On the contrary, evidence is mounting that this practice will select for biotypes that are resistant to the herbicides used, especially where herbicides of the same mode of action are used continuously. It is essential, therefore, that herbicides be considered as just one component of an overall integrated System together with cultural control and other management strategies, and that agronomic principles be considered when developing this System.

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