scholarly journals Managing glyphosate resistance in Australian cotton farming: modelling shows how to delay evolution and maintain long-term population control

2013 ◽  
Vol 64 (8) ◽  
pp. 780 ◽  
Author(s):  
David Thornby ◽  
Jeff Werth ◽  
Steven Walker
Keyword(s):  
Weed Control ◽  
Population Control ◽  
Management Strategies ◽  
Farming Systems ◽  
Glyphosate Resistance ◽  
Weed Species ◽  
Barnyard Grass ◽  
Resistance Evolution ◽  
Seed Bank Dynamics

Glyphosate resistance is a rapidly developing threat to profitability in Australian cotton farming. Resistance causes an immediate reduction in the effectiveness of in-crop weed control in glyphosate-resistant transgenic cotton and summer fallows. Although strategies for delaying glyphosate resistance and those for managing resistant populations are qualitatively similar, the longer resistance can be delayed, the longer cotton growers will have choice over which tactics to apply and when to apply them. Effective strategies to avoid, delay, and manage resistance are thus of substantial value. We used a model of glyphosate resistance dynamics to perform simulations of resistance evolution in Sonchus oleraceus (common sowthistle) and Echinochloa colona (awnless barnyard grass) under a range of resistance prevention, delaying, and management strategies. From these simulations, we identified several elements that could contribute to effective glyphosate resistance prevention and management strategies. (i) Controlling glyphosate survivors is the most robust approach to delaying or preventing resistance. High-efficacy, high-frequency survivor control almost doubled the useful lifespan of glyphosate from 13 to 25 years even with glyphosate alone used in summer fallows. (ii) Two non-glyphosate tactics in-crop plus two in-summer fallows is the minimum intervention required for long-term delays in resistance evolution. (iii) Pre-emergence herbicides are important, but should be backed up with non-glyphosate knockdowns and strategic tillage; replacing a late-season, pre-emergence herbicide with inter-row tillage was predicted to delay glyphosate resistance by 4 years in awnless barnyard grass. (iv) Weed species’ ecological characteristics, particularly seed bank dynamics, have an impact on the effectiveness of resistance strategies; S. oleraceus, because of its propensity to emerge year-round, was less exposed to selection with glyphosate than E. colona, resulting in an extra 5 years of glyphosate usefulness (18 v. 13 years) even in the most rapid cases of resistance evolution. Delaying tactics are thus available that can provide some or many years of continued glyphosate efficacy. If glyphosate-resistant cotton cropping is to remain profitable in Australian farming systems in the long-term, however, growers must adapt to the probability that they will have to deal with summer weeds that are no longer susceptible to glyphosate. Robust resistance management systems will need to include a diversity of weed control options, used appropriately.

scholarly journals Efficacy of the herbicide GF-2581 (penoxsulam + florasulam) against broadleaf weeds in olives

2014 ◽  
Vol 60 (No. 12) ◽  
pp. 574-579 ◽  
Author(s):  
Travlos IS ◽  
M. Lysandrou ◽  
V. Apostolidis
Keyword(s):  
Weed Control ◽  
Management Strategies ◽  
Growing Season ◽  
Field Trials ◽  
Conyza Canadensis ◽  
Weed Species ◽  
Stellaria Media ◽  
Excellent Control ◽  
Control Management

Effective weed control in perennial crops is a challenge due to the limited availability of registered herbicides and herbicide resistance. The objective of the study was to evaluate the efficacy of the herbicide GF-2581 (penoxsulam + florasulam) on broadleaf weeds in comparison with other commonly used herbicides. Field trials were conducted in olives, in Etoloakarnania (Agrinio region) for two years (2012 and 2013). Efficacy assessments were made at 30, 60, 90 and 120 days after treatment. The GF-2581 formulation provided excellent control of a broad spectrum of broadleaf weed species. The long-term control of Sonchus oleraceous, Conyza canadensis and Stellaria media, provided by GF-2581 during the growing season was significantly greater than that using flumioxazin. When combined with glyphosate or diquat, the level of control of these three weeds was improved. The GF-2581 agent applied pre-emergence followed 14 days later by application of glyphosate provided 100% control in 2012. Lower efficacy levels were observed in 2013 and may have been the result of higher rainfall when compared to 2012. GF-2581 is an effective herbicide product to control broadleaf weeds, as a part of integrated weed control management strategies in olives.

Rice weed control: current technology and emerging issues in temperate rice

1994 ◽  
Vol 34 (7) ◽  
pp. 1021 ◽  
Author(s):  
JE Hill ◽  
RJ Jr Smith ◽  
DE Bayer
Keyword(s):  
United States ◽  
Weed Control ◽  
Cultural Practices ◽  
Management Strategies ◽  
The United States ◽  
Weed Species ◽  
Rice Culture ◽  
Emerging Issues ◽  
Direct Seeded ◽  
The Cost

Among temperate rice areas, the United States and Australia are most similar in climate and in the mechanisation of rice culture. Many weed problems, even weed species invading rice, are common to both countries; and the present technology for weed control as well as concern for the impact of these technologies to environmental quality, herbicide resistance, and other weed-related issues bear many similarities. Application of current, and any new, technologies to emerging issues in US rice weed control will therefore be directly relevant to rice production in Australia and all other temperate areas struggling with the same challenges. Weeds are a significant problem in temperate rice culture. In the United States, rice is mechanically direct-seeded, allowing weeds to germinate and establish with the crop. In the last 15 years weed growth and competition has been increased by the adoption of semi-dwarf cultivars, high N fertilisation, and, in water-seeded rice, shallow flooding. High rates, and often multiple applications, of herbicides have been necessary to maximise the yield potential of these cultural systems. Advances in cultural practices and herbicide technology have maintained, if not improved, weed control; but nearly 30 years of propanil use in the southern USA resulted in propanil-resistant barnyard grass Echinochloa crus-galli (L.) Beauv., and after 4 years of continuous use, bensulfuron resistance to 4 aquatic weed species was discovered in California. Although herbicides with different mechanisms of action are needed for alternation in resistance management strategies, fewer are likely to be available. Social and environmental concerns have slowed the development and registration of rice herbicides and increased the cost of controlling weeds. Water quality deterioration from ricefield tailwaters, drift to sensitive crops, the cost of renewing registration in aquatic systems, and weed resistance all forecast reduced herbicide use in rice. Neither cultural practices nor herbicides alone can solve weed problems in direct-seeded, mechanised rice culture. With fewer herbicides and a cultural system highly vulnerable to weed losses, integrated management strategies with better information on which to base weed control decisions will be needed to solve weed problems in temperate rice.

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 Weed Management Strategies in Chickpea (Cicer arietinum): A Review

2020 ◽  
Author(s):  
Akashdeep Singh ◽  
S. S. Rana ◽  
Anju Bala
Keyword(s):  
Weed Control ◽  
Cicer Arietinum ◽  
Weed Management ◽  
Management Practices ◽  
Management Strategies ◽  
Detailed Knowledge ◽  
Basic Requirement ◽  
Weed Species ◽  
The World ◽  
Hand Weeding

Chickpea (Cicer arietinum) is one of the most important pulse crops but it’s productivity in India is quite low. There are various reasons for low productivity. Weed control is the basic requirement and the major component of crop management. Weeds on an average reduce the crop yield by 40-87 per cent. Deciding time to control weeds requires detailed knowledge of the weed populations in the field. Different management practices like altering spacing, competitive cultivars, etc. can help in enhancing the productivity. With the world entering the precision-farming era, more emphasis is being put on the use of post-emergence herbicides. Application of two or more herbicide at the same time or as a double knockdown and integrating with hand-weeding provides desirable control of different weed species besides reducing the hazard of chemical weed control.

scholarly journals Revisiting the concept of the critical period of weed control

2022 ◽  
pp. 1-7
Author(s):  
K. Ramesh ◽  
S. Vijaya Kumar ◽  
P. K. Upadhyay ◽  
B. S. Chauhan
Keyword(s):  
Weed Control ◽  
Crop Yield ◽  
Critical Period ◽  
Management Practice ◽  
Cumulative Effect ◽  
Farming Systems ◽  
Time Interval ◽  
Weed Species ◽  
Weed Density ◽  
Critical Timing

Abstract Weeds are a major biotic constraint to the production of crops. Studies on the critical period of weed control (CPWC) consider the yield loss due to the presence of all weeds present in the crop cycle. The CPWC is the time interval between the critical timing of weed removal (CTWR) and the critical weed-free period (CWFP), and the weed presence before and after the extremes of CTWR and CWFP may not significantly reduce crop yield. The crop yield is taken into consideration and weed density or biomass of individual weeds (annual or perennial) is not so important while calculating the CPWC. Only weed density or biomass is considered for calculating weed control efficiency of a particular management practice for which the weed seed bank is also a criterion. However, weed biomass is the outcome after competition experienced by each weed species with the fellow crop and the weeds. Consequently, the weed pressure in the subsequent season will be the cumulative effect of the preceding season too, which is unaccounted for in CPWC. It is argued that in organic farming or low-input farming systems, where herbicides are not used, the concept of CPWC can be misleading and should be avoided. It is concluded that CTWR is more meaningful than the CPWC.

Weed Succession under Conservation Tillage: A Hierarchical Framework for Research and Management

1993 ◽  
Vol 7 (2) ◽  
pp. 286-297 ◽  
Author(s):  
Clarence J. Swanton ◽  
David R. Clements ◽  
Douglas A. Derksen
Keyword(s):  
Species Composition ◽  
Conservation Tillage ◽  
Management Strategies ◽  
Research Approach ◽  
Weed Species ◽  
Ecological Processes ◽  
Succession Management ◽  
Hierarchical Framework ◽  
Species Performance

The awareness and adoption of conservation tillage is one of the most important changes taking place in agriculture today. There are, however, concerns regarding weed species shifts under conservation tillage. Under conservation tillage, shifts toward grass, perennial, wind-disseminated weeds and volunteer crop plants have been observed. Shifts in weed species composition may either represent long-term ecological succession or temporary fluctuations in species composition; few long-term studies have examined the ecology of these shifts in detail. Further studies are needed to identify mechanisms driving these shifts to determine whether they are fluctuational or successional and to develop more sophisticated management strategies. In this paper, we present a research approach for studying ecological processes such as competition within a hierarchical framework of all possible causes, processes, and defining factors related to weed succession under conservation tillage. Succession management strategies can be developed to act at the causal level in the successional hierarchy. Three primary causes are site availability, colonization, and species performance. Site availability may be controlled through “designed disturbance”, while differential species availability may be regulated through “controlled colonization” and species performance may be regulated through “controlled species performance”. In general, the goals of succession management would involve reducing populations of the weed species most likely to proliferate under conservation tillage. Comprehensive ecological research, within the hierarchical framework outlined here, would identify potential problems and enable management strategies to account for the numerous factors that may be influencing fluctuations and succession of weeds under conservation tillage.

Effect of Crop Residue on Seedling Emergence and Growth of Selected Weed Species in a Sprinkler-Irrigated Zero-Till Dry-Seeded Rice System

Weed Science ◽  
2013 ◽  
Vol 61 (3) ◽  
pp. 403-409 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
Seth B. Abugho
Keyword(s):  
Field Study ◽  
Weed Control ◽  
Weed Management ◽  
Crop Residue ◽  
Crop Residues ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Weed Species ◽  
Weed Biomass ◽  
Residue Retention

Crop residues acting as mulches can influence weed seedling emergence and weed biomass. A field study was conducted to evaluate the effect of rice residue amounts (0, 3, and 6 t ha−1) on seedling emergence of eight weed species in zero-till dry-seeded rice. The highest seedling emergence of spiny amaranth, southern crabgrass, crowfootgrass, junglerice, eclipta, goosegrass, and Chinese sprangletop was observed in the absence of residue. Seedling emergence of these weeds declined with increasing residue amounts; however, the greatest and most substantial reductions in emergence occurred with 6 t ha−1of residue. The presence of residue also resulted in less weed biomass than with the no-residue treatment. The emergence and biomass of threelobe morningglory seedlings, however, were not influenced by residue amounts. The use of residue also increased the time taken to reach 50% of maximum emergence for some species, for example, spiny amaranth and Chinese sprangletop. The results of our study suggest that the use of residue at high rates can help suppress seedling emergence and growth of many weeds. However, there is a need to integrate other weed management strategies with residue retention to achieve season-long weed control.

Broadleaf Weed Control in Winter-Sown Lentil (Lens culinaris)

2015 ◽  
Vol 29 (1) ◽  
pp. 56-62 ◽  
Author(s):  
Hassan Karimmojeni ◽  
Ali Reza Yousefi ◽  
Per Kudsk ◽  
Amir Hossein Bazrafshan
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Lens Culinaris ◽  
Management Strategies ◽  
Effective Control ◽  
Weed Species ◽  
Leaf Stage ◽  
Free Treatment ◽  
Hand Weeding ◽  
Herbicide Management

Winter sowing of lentil results in higher yields than a spring-sown crop. However, when lentil is winter-sown, the critical period of weed control is extended and might require sequential herbicide management strategies to obtain maximum yields. The efficacy of POST alone or soil applied followed by (fb) POST herbicides or hand weeding were evaluated in 2002 and 2003. Trifluralin (PPI) or pendimethalin (PRE) were applied at planting, and pyridate or oxyfluorfen were applied POST at the three- to four-leaf stage of lentil. The lowest level of weed biomass was recorded with all treatments, except pyridate alone in both years, pendimethalin PRE fb pyridate in 2002, and oxyfluorfen in 2003. Application of pyridate or oxyfluorfen POST alone resulted in lower yields. In 2002, trifluralin PPI or pendimethalin PRE fb one hand weeding or pendimethalin fb pyridate resulted in yields similar to the weed-free treatment. In 2003, yields were similar to the weed-free treatment, except pyridate or oxyfluorfen alone and trifluralin PPI fb oxyfluorfen. Weed species observed in the present study required sequential management to achieve both effective control and maximum lentil yield.

scholarly journals Germination ecology of Ambrosia artemisiifolia L. and Ambrosia trifida L. biotypes suspected of glyphosate resistance

2013 ◽  
Vol 8 (3) ◽  
pp. 286-296 ◽  
Author(s):  
Giovanni Dinelli ◽  
Ilaria Marotti ◽  
Pietro Catizone ◽  
Sara Bosi ◽  
Asif Tanveer ◽  
...  
Keyword(s):  
Management Strategies ◽  
Glyphosate Resistance ◽  
Ambrosia Artemisiifolia ◽  
Threshold Temperature ◽  
Weed Species ◽  
Sowing Depth ◽  
Roundup Ready ◽  
Germination Ecology ◽  
Marginal Areas ◽  
Similar Threshold

AbstractThe germination ecology of Ambrosia artemisiifolia and A. trifida glyphosate susceptible biotypes sampled in marginal areas, was compared with that of the same species but different biotypes suspected of glyphosate resistance, common and giant ragweed, respectively. The suspected resistant biotypes were sampled in Roundup Ready® soybean fields. Within each weed species, the seeds of the biotype sampled in marginal area were significantly bigger and heavier than those of the biotype sampled in the soybean fields. A. artemisiifolia biotypes exhibited a similar dormancy and germination, while differences between A. trifida biotypes were observed. A. artemisiifolia biotypes showed similar threshold temperature for germination, whereas, the threshold temperature of the susceptible A. trifida biotype was half as compared to that of the resistant A. trifida biotype. No significant differences in emergence as a function of sowing depth were observed between susceptible A. artemisiifolia and suspected resistant A. trifida biotype, while at a six-cm seedling depth the emergence of the A. artemisiifolia susceptible biotype was 2.5 times higher than that of the A. trifida suspected resistant biotype. This study identified important differences in seed germination between herbicide resistant and susceptible biotypes and relates this information to the ecology of species adapted to Roundup Ready® fields. Information obtained in this study supports sustainable management strategies, with continued use of glyphosate as a possibility.

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