The impact of glyphosate-tolerant crops on the use of other herbicides and on resistance management

Shaner, Dale L.

doi:10.1002/(sici)1526-4998(200004)56:4<320::aid-ps125>3.0.co;2-b

Cited by 187 publications

(114 citation statements)

References 17 publications

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“…and Sorghum halepense , reported to have glyphosate resistance elsewhere in South America. As herbicide resistant crops (transgenic or not) are increasingly deployed in developing countries, the problems of EHR will likely spread to those countries [32].…”

Section: Resultsmentioning

confidence: 99%

Taxonomic and Life History Bias in Herbicide Resistant Weeds: Implications for Deployment of Resistant Crops

et al. 2013

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Evolved herbicide resistance (EHR) is an important agronomic problem and consequently a food security problem, as it jeopardizes herbicide effectiveness and increases the difficulty and cost of weed management. EHR in weeds was first reported in 1970 and the number of cases has accelerated dramatically over the last two decades. Despite 40 years of research on EHR, why some weeds evolve resistance and others do not is poorly understood. Here we ask whether weed species that have EHR are different from weeds in general. Comparing taxonomic and life history traits of weeds with EHR to a control group (“the world's worst weeds”), we found weeds with EHR significantly over-represented in certain plant families and having certain life history biases. In particular, resistance is overrepresented in Amaranthaceae, Brassicaceae and Poaceae relative to all weeds, and annuality is ca. 1.5 times as frequent in weeds with EHR as in the control group. Also, for perennial EHR weeds, vegetative reproduction is only 60% as frequent as in the control group. We found the same trends for subsets of weeds with EHR to acetolactate synthase (ALS), photosystem II (PSII), and 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase-inhibitor herbicides and with multiple resistance. As herbicide resistant crops (transgenic or not) are increasingly deployed in developing countries, the problems of EHR could increase in those countries as it has in the USA if the selecting herbicides are heavily applied and appropriate management strategies are not employed. Given our analysis, we make some predictions about additional species that might evolve resistance.

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Section: Resultsmentioning

confidence: 99%

Taxonomic and Life History Bias in Herbicide Resistant Weeds: Implications for Deployment of Resistant Crops

et al. 2013

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“…All of these effects are critically important given the increase in glyphosate-resistant weed species such as Palmer amaranth, johnsongrass, giant ragweed (Ambrosia trifida L.), and goosegrass [Eleusine indica (L.) Gaertn.] throughout the midsouthern United States (Green and Owen 2011;Heap 2014;Osunsami 2009;Reddy and Norsworthy 2010;Riar et al 2011;Shaner 2000). Therefore, understanding the dominant routes, mechanisms, and rates of weed spread across landscapes is of utmost importance for preventing the spatial weed infestation and subsequent spread of herbicide-resistant biotypes.…”

mentioning

confidence: 99%

Distribution of Arable Weed Populations along Eastern Arkansas–Mississippi Delta Roadsides: Factors Affecting Weed Occurrence

et al. 2015

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The occurrence of 36 arable weed species across 13 counties in the eastern Arkansas–Mississippi Delta area on 489 randomly selected road sites was surveyed in 2012. Palmer amaranth, johnsongrass, large crabgrass, barnyardgrass, prickly sida, and broadleaf signalgrass were the top six weed species, with occurrence noted at 313, 294, 261, 238, 176, and 136 sites, respectively. Factors found to affect weed occurrence along Mississippi Delta roadsides included topographical characteristics, weed species, ditch slope, road type, and nearby land use. Among roadside topographical characteristics, road shoulder was found to strongly affect weed occurrence. In addition, paved and gravel road types with moderate roadside slope explained most of the variability of weed occurrence at each sampling site. Additionally, nearby arable land use affected weed occurrence more so than natural, residential, and pastoral land. Barnyardgrass, johnsongrass, and Palmer amaranth were 3.6 to 4.3 times more likely to occur than all other species identified. An effective weed management plan along eastern Arkansas–Mississippi Delta roadsides should focus on road shoulder, adjacent arable land use, road type, and specific weed species (e.g., Palmer amaranth, johnsongrass, and barnyardgrass). The inclusion of these parameters in future weed control programs can prove invaluable for preventing the spread of the herbicide-resistant Palmer amaranth, barnyardgrass, and johnsongrass.

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“…Weeds emerging after a glyphosate application can fill niches vacated by the weeds that were effectively controlled by glyphosate. While Verschwele and Mülleder (2008) showed that risks for weed population shifts from GMHT crops are no greater than those associated with other herbicides and non-GMHT crops, other studies reported or predicted shifts in weed populations due the increased frequency and rate of glyphosate use in GMHT crops (e.g., Shaner, 2000;Hilgenfeld et al, 2004;Duke, 2005;Owen and Zelaya, 2005;Puricelli and Tuesca, 2005;Culpepper, 2006;Scursoni et al, 2007;Owen, 2000Owen, , 2008. A survey of twelve weed scientists from eleven states across the USA, to assess weed shifts in GMHT maize, cotton and soybean, revealed that no weed shifts were observed in GMHR maize yet, and that this was attributed to the low adoption of GMHR maize (Culpepper, 2006).…”

Section: Weed Shifts and The Selection Of Weed Communities Composed Omentioning

confidence: 99%

“…In a 6-year field study, Verschwele and Mülleder (2008) considered potential changes in weed communities due to the use of glyphosate in a continuous maize NK603 rotation at three sites in Germany, and did not observe statistically significant differences between local standard herbicide treatments and the glyphosate-based treatments on the mean values of seedbank, species richness, species diversity and dominance (see also Verschwele, 2011). With the anticipated increase in adoption of GMHR maize as well as application rates of glyphosate, more frequent weed shifts have been predicted (Shaner, 2000). While Verschwele and Mülleder (2008) showed that risks for weed population shifts from GMHT crops are no greater than those associated with other herbicides and non-GMHT crops, other studies reported or predicted shifts in weed populations due the increased frequency and rate of glyphosate use in GMHT crops (e.g., Shaner, 2000;Hilgenfeld et al, 2004;Duke, 2005;Owen and Zelaya, 2005;Puricelli and Tuesca, 2005;Culpepper, 2006;Scursoni et al, 2007;Owen, 2000Owen, , 2008.…”

Section: Weed Shifts and The Selection Of Weed Communities Composed Omentioning

confidence: 99%

Scientific Opinion on application (EFSA-GMO-UK-2008-60) for placing on the market of genetically modified herbicide tolerant maize GA21 for food and feed uses, import, processing and cultivation under Regulation (EC) No 1829/2003 from Syngenta Seeds

2011

EFSA Journal

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This Scientific Opinion reports on an evaluation of a risk assessment for placing on the market of genetically modified maize GA21 for food and feed uses, import, processing and cultivation. Maize GA21 was developed through particle bombardment and contains a single insertion locus consisting of modified maize epsps (mepsps) gene, conferring tolerance to glyphosate-based herbicides. Bioinformatic analyses and levels of the mEPSPS protein were considered sufficient. The comparative analysis of compositional, agronomic and phenotypic characteristics indicated that maize GA21 is not different from the conventional counterpart and its composition fell within the range observed among non-GM maize varieties, except for the presence of the mEPSPS protein in maize GA21. The safety assessment of maize GA21 identified no concerns regarding potential toxicity and allergenicity. A feeding study with broiler chickens confirmed that maize GA21 is as nutritious as its conventional counterpart. The EFSA GMO Panel considers that maize GA21 is unlikely to raise additional environmental safety concerns compared to conventional maize, but that its cultivation management could result in environmental harm under certain conditions. The EFSA GMO Panel therefore recommends managing the use of glyphosate on maize GA21 within diversified cropping regimes that have similar or reduced environmental impacts compared with conventional maize cultivation. The EFSA GMO Panel recommends the deployment of case-specific monitoring to address (1) changes in botanical diversity within fields due to novel herbicide regimes, and (2) resistance evolution to glyphosate in weeds due to novel herbicide regimes. The EFSA GMO Panel agrees with the general surveillance plan of the applicant, but requests that its proposals to strengthen general surveillance are implemented. The EFSA GMO Panel concludes that the information available for maize GA21 addresses the scientific comments raised by Member States and that maize GA21, as described in this application, is as safe as its conventional counterpart and commercial maize varieties with respect to potential adverse effects on human and animal health. If subjected to appropriate management measures, the cultivation management of maize GA21 is unlikely to raise safety concerns for the environment.

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The impact of glyphosate-tolerant crops on the use of other herbicides and on resistance management

Cited by 187 publications

References 17 publications

Taxonomic and Life History Bias in Herbicide Resistant Weeds: Implications for Deployment of Resistant Crops

Taxonomic and Life History Bias in Herbicide Resistant Weeds: Implications for Deployment of Resistant Crops

Distribution of Arable Weed Populations along Eastern Arkansas–Mississippi Delta Roadsides: Factors Affecting Weed Occurrence

Scientific Opinion on application (EFSA-GMO-UK-2008-60) for placing on the market of genetically modified herbicide tolerant maize GA21 for food and feed uses, import, processing and cultivation under Regulation (EC) No 1829/2003 from Syngenta Seeds

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