Integrated approaches to managing weeds in spring-sown crops in western Canada

O’Donovan, John T.; Blackshaw, Robert E.; Harker, K. Neil; Clayton, George W.; Moyer, J. R.; Dosdall, Lloyd M.; Maurice, D.; Turkington, T. K.

doi:10.1016/j.cropro.2005.09.018

Cited by 62 publications

(58 citation statements)

References 59 publications

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“…Delayed herbicide application increases the duration of weed interference, ultimately resulting in lower grain yields. The importance of early weed removal for reducing weed interference and improving crop yield has been previously demonstrated in other crops (Harker et al 2001;O'Donovan et al 2007O'Donovan et al , 2008Harker et al 2008).…”

Section: Grain Yield and Kernel Characteristicsmentioning

confidence: 99%

“…However, a one-pass herbicideÁfungicide application may not provide direct protection from pathogens for the upper cereal canopy leaves, which are crucial for grain filling and yield. Moreover, if the application is delayed to the five-to six-leaf stage it may compromise the level of weed management, given that previous research has confirmed the importance of early weed removal in several crop species (Harker et al 2001O'Donovan et al 2007O'Donovan et al , 2008.…”

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confidence: 99%

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The impact of fungicide and herbicide timing on foliar disease severity, and barley productivity and quality

et al. 2015

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. 2015. The impact of fungicide and herbicide timing on foliar disease severity, and barley productivity and quality. Can. J. Plant Sci. 95: 525Á537. There is interest in mixing herbicides with a half-rate of fungicide at herbicide timings for barley in western Canada. At six sites across the Canadian prairies from 2010 to 2012 combinations of herbicide and the fungicide Tilt † (propiconazole) were applied to barley at the two-to three-leaf stage (herbicide and half-rate fungicide), five-to six-leaf stage (herbicide and half-rate fungicide), and/or the flag leaf stage (full or half-rate fungicide only). Each plot area was cross-seeded with tame oat as a model weed prior to seeding. Upper canopy leaf samples were collected for leaf disease assessment at the early dough growth stage. Weed biomass, and grain yield and quality were determined. Total leaf area diseased (a combination of scald, both forms of net blotch and spot blotch) was greater for the two-to three-or five-to six-leaf stage herbicide-only treatments and the combination herbicide and half-rate fungicide treatments compared with fungicide at the flag leaf stage. Yield, 1000-kernel weight, kernel plumpness and test weight were greatest and kernel thins lowest for treatments with a flag leaf stage fungicide application. Split applications of fungicide at the time of herbicide application and at flag leaf emergence did not improve disease management and crop productivity compared with a single full rate fungicide application at the flag leaf stage. Weed biomass was generally not influenced by the treatments because weed control was excellent at all sites. However, yield was lower when herbicide was applied at the five-to six-leaf versus the two-to three-leaf stage. For improved leaf disease management and yield in barley, fungicide applications should include a flag leaf stage timing for adequate protection of upper canopy leaves, which are key contributors to yield and grain filling. Delaying herbicide application to the five-to six-leaf stage in an attempt to accommodate a fungicide application reduces barley yield due to early-season weed interference.Key words: Fungicide, herbicide, timing, leaf disease, barley Turkington, T. K., O'Donovan, J. T., Harker, K. N., Xi, K., Blackshaw, R. E., Johnson, E. N., Peng, G., Kutcher, H. R., May, W. E., Lafond, G. P., Mohr, R. M., Irvine, R. B. et Stevenson, C. 2015. Impact du moment d'application des fongicides et des herbicides sur la gravite´des maladies foliaires ainsi que sur la productivite´et la qualite´de l'orge. Can. J. Plant Sci. 95: 525Á537. Les producteurs d'orge de l'Ouest canadien souhaiteraient ajouter un fongicide, a`la moitie´du taux recommande´, au moment de l'application des herbicides. De 2010 a`2012, a`six sites des Prairies canadiennes, les auteurs ont applique´des me´langes d'herbicide et du fongicide Tilt † (propiconazole) a`de l'orge parvenu au stade de la deuxie`me ou de la troisie`me feuille (fongicide a`la moitie´du taux recommande´et herbicide), a`celui de la cinquie`me ou de la sixi...

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Section: Grain Yield and Kernel Characteristicsmentioning

confidence: 99%

mentioning

confidence: 99%

The impact of fungicide and herbicide timing on foliar disease severity, and barley productivity and quality

et al. 2015

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“…Although considerable literature exists on the use of sublethal herbicide doses to provide sufficient weed control (reviewed by Zhang et al, 2000;O'Donovan et al, 2007), very few studies have analyzed the subsequent genetic evolutionary consequences of such a low-dose selection (Gressel, 1995). If a herbicide is used at a sublethal dose, then the (low) selection pressure acting within the phenotypic variation is evident in the population and there will likely be survivors.…”

Section: Introductionmentioning

confidence: 99%

Evolution of glyphosate resistance in a Lolium rigidum population by glyphosate selection at sublethal doses

2009

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The majority of the documented cases of field-evolved herbicide-resistant weed biotypes established that single major genes confer glyphosate resistance. However, the contribution of minor genes endowing substantial plant survival at sublethal herbicide doses may be a potential complementary path to herbicide resistance evolution in weed populations under selection. Here, we subjected a number of susceptible individuals of Lolium rigidum to recurrent glyphosate selection to test the potential for sublethal glyphosate doses to additively select for glyphosate resistance. After 3-4 cycles of glyphosate selection in two distinct environments, the progenies of the initially susceptible population were shifted toward glyphosate resistance. The results indicate progressive enrichment of minor gene trait(s) contributing toward plant survival in the glyphosate-selected progenies. After three generations of selection, the estimated LD 50 values were doubled compared with the original population and up to 33% plant survival was obtained in the glyphosate-selected progeny at the recommended glyphosate label rate. This level of resistance probably was the maximum shift achievable with sublethal glyphosate dose selection in this small population. Cross-pollination was a crucial factor enabling the rapid rate of accumulation of minor glyphosate resistance gene trait(s) that are likely to be present at a relatively high frequency in a small susceptible population. The mechanistic basis of the moderate glyphosate resistance level selected by sublethal glyphosate doses remains unknown and warrants future research. Studying the main factors influencing the evolution of resistant weed populations is crucial for understanding, predicting and managing herbicide resistance.

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“…While all of these studies included some form of chemical management in the protocol, all related their work to potential for organic systems. Sweetclover green manure used in lieu of fallow in dryland systems strongly suppressed weeds whether harvested as hay, left on the surface, or incorporated [35,39]. The authors suggest that some of the weed suppression effect of sweetclover may have been due to allelopathic compounds.…”

Section: Weed Managementmentioning

confidence: 91%

“…There have been a number of integrated weed management studies in south-central Alberta incorporating cover crops, underseeding and green manures [35][36][37][38][39]. While all of these studies included some form of chemical management in the protocol, all related their work to potential for organic systems.…”

Section: Weed Managementmentioning

confidence: 99%

The Sustainability of Organic Grain Production on the Canadian Prairies—A Review

Snyder

Spaner

2010

Sustainability

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Demand for organically produced food products is increasing rapidly in North America, driven by a perception that organic agriculture results in fewer negative environmental impacts and yields greater benefits for human health than conventional systems. Despite the increasing interest in organic grain production on the Canadian Prairies, a number of challenges remain to be addressed to ensure its long-term sustainability. In this review, we summarize Western Canadian research into organic crop production and evaluate its agronomic, environmental, and economic sustainability.

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Integrated approaches to managing weeds in spring-sown crops in western Canada

Cited by 62 publications

References 59 publications

The impact of fungicide and herbicide timing on foliar disease severity, and barley productivity and quality

The impact of fungicide and herbicide timing on foliar disease severity, and barley productivity and quality

Evolution of glyphosate resistance in a Lolium rigidum population by glyphosate selection at sublethal doses

The Sustainability of Organic Grain Production on the Canadian Prairies—A Review

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