Articles de revues : « Triazine herbicide »

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Parker, Ethan T., Micheal D. K. Owen, Mark L. Bernards, William S. Curran, Lawrence E. Steckel et Thomas C. Mueller. « A Comparison of Symmetrical and Asymmetrical Triazine Herbicides for Enhanced Degradation in Three Midwestern Soils ». Weed Science 66, n^o 5 (septembre 2018) : 673–79. http://dx.doi.org/10.1017/wsc.2018.41.

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AbstractThe triazines are one of the most widely used herbicide classes ever developed and are critical for managing weed populations that have developed herbicide resistance. These herbicides are traditionally valued for their residual weed control in more than 50 crops. Scientific literature suggests that atrazine, and perhaps others-triazines, may no longer remain persistent in soils due to enhanced microbial degradation. Experiments examined the rate of degradation of atrazine and two other triazine herbicides, simazine and metribuzin, in both atrazine-adapted and non-history Corn Belt soils, with similar soils being used from each state as a comparison of potential triazine degradation. In three soils with no history of atrazine use, thet1/2of atrazine was at least four times greater than in three soils with a history of atrazine use. Simazine degradation in the same three sets of soils was 2.4 to 15 times more rapid in history soils than non-history soils. Metribuzin in history soils degraded at 0.6, 0.9, and 1.9 times the rate seen in the same three non-history soils. These results indicate enhanced degradation of the symmetrical triazine simazine, but not of the asymmetrical triazine metribuzin.

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Perry, D. H., J. S. McElroy, F. Dane, E. van Santen et R. H. Walker. « Triazine-Resistant Annual Bluegrass (Poa annua) Populations with Ser264Mutation Are Resistant to Amicarbazone ». Weed Science 60, n^o 3 (septembre 2012) : 355–59. http://dx.doi.org/10.1614/ws-d-11-00200.1.

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Amicarbazone is a photosystem II (PSII)-inhibiting herbicide in the triazolinone family, which is similar in mode of action to the triazines. Annual bluegrass is a cool-season weed and has shown resistance to some PSII-inhibiting herbicides. The objective was to evaluate triazine-resistant and -susceptible annual bluegrass populations for potential cross-resistance to amicarbazone. Two triazine-resistant (MS-01, MS-02) and triazine-susceptible (AL-01, COM-01) annual bluegrass populations were treated with amicarbazone, atrazine, and simazine at 0.26, 1.7, and 1.7 kg ai ha−1, respectively. All herbicide treatments controlled the susceptible populations greater than 94% 2 wk after treatment (WAT). No visual injury of MS-01 and MS-02 was observed at any time following herbicide treatment. Quantum yield (ΦPSII) of annual bluegrass was measured 0 to 72 h after application (HAA) to determine the photochemical effects of amicarbazone compared to other PSII inhibitors. ΦPSIIof triazine-susceptible populations was reduced at all measurement times by all three herbicides. However, amicarbazone decreased ΦPSIIof susceptible populations faster and greater than atrazine and simazine at most measurement times. Amicarbazone did not reduce ΦPSIIof the MS-01 population. Amicarbazone significantly reduced ΦPSIIof the MS-02 population during several measurement timings; however, these reductions were short-lived compared to the susceptible populations and no trend in ΦPSIIreduction was observed. Sequencing of thepsbAgene revealed a Ser to Gly substitution at amino acid position 264 known to confer resistance to triazine herbicides. These data indicate amicarbazone efficiently inhibited PSII of susceptible annual bluegrass populations; however, triazine-resistant annual bluegrass populations with Ser264to Gly mutations are cross-resistant to amicarbazone.

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Zainal Abidin, Nurul Auni, Nur Sofiah Abu Kassim et Noor Hidayah Pungot. « Solid Phase Extraction Method for the Determination of Atrazine and Cyanazine in Water Samples ». ASM Science Journal 14 (2 avril 2021) : 1–6. http://dx.doi.org/10.32802/asmscj.2020.631.

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Triazine is one of the herbicides group that is widely used in agriculture that acts as an inhibitor for the growth of unwanted weeds in plants. The use of this herbicide on plants is absorbed by the soil and flows into a nearby water system. This research focused on two types of triazines, namely atrazine and cyanazine. This research aims to extract this type of triazine herbicides and to determine their concentration in water samples. It was quantified by using gas chromatography-electron capture detector (GC-ECD). Solid phase extraction (SPE) method was applied to extract herbicides from water samples. The results indicate that all the samples contained atrazine and cyanazine. Studies in the range of 0.5 - 25 mg/L achieved good linearity with good correlation of determination, r2 value of 0.9922 - 0.9982 mg/L. Relative standard deviations (RSD) for triplicate analysis of the samples were less than 10.0%. The limit of detection (LODs) and limit of quantification (LOQs) of cyanazine and atrazine were found, ranging from 3.33 – 6.67 μg/L and 11.09 – 20.10 μg/L, respectively. The recoveries of the triazine herbicides studied in water samples ranged from 82.5% to 107.6%. The developed method exhibited excellent clean-up capability and was successfully applied for determining triazine herbicide residues in water samples.

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GAYNOR, J. D., J. A. STONE et T. J. VYN. « TILLAGE SYSTEMS AND ATRAZINE AND ALACHLOR RESIDUES ON A POORLY DRAINED SOIL ». Canadian Journal of Soil Science 67, n^o 4 (1 novembre 1987) : 959–63. http://dx.doi.org/10.4141/cjss87-091.

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Seasonal residues of an acetanilide and triazine herbicide were monitored in ridge, conventional, and zero tillage systems. Alachlor (2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide), and atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) residues were less than 8% of the spring application concentration at the end of the growing season. Moldboard plowing in the fall reduced herbicide residues in spring because of soil dilution by plowing to greater than the sampling depth. Ridge tillage systems had higher spring residues apparently because of reduced herbicide dissipation on the drier ridge tops. The higher residues of the triazines on ridge tops may be injurious to triazine sensitive crops. Key words: Herbicide, till-plant, ridge tillage, des-ethyl atrazine

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Shaner, Dale L. « Lessons Learned From the History of Herbicide Resistance ». Weed Science 62, n^o 2 (juin 2014) : 427–31. http://dx.doi.org/10.1614/ws-d-13-00109.1.

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The selection of herbicide-resistant weed populations began with the introduction of synthetic herbicides in the late 1940s. For the first 20 years after introduction, there were limited reported cases of herbicide-resistant weeds. This changed in 1968 with the discovery of triazine-resistant common groundsel. Over the next 15 yr, the cases of herbicide-resistant weeds increased, primarily to triazine herbicides. Although triazine resistance was widespread, the resistant biotypes were highly unfit and were easily controlled with specific alternative herbicides. Weed scientists presumed that this would be the case for future herbicide-resistant cases and thus there was not much concern, although the companies affected by triazine resistance were somewhat active in trying to detect and manage resistance. It was not until the late 1980s with the discovery of resistance to Acetyl Co-A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors that herbicide resistance attracted much more attention, particularly from industry. The rapid evolution of resistance to these classes of herbicides affected many companies, who responded by first establishing working groups to address resistance to specific classes of herbicides, and then by formation of the Herbicide Resistance Action Committee (HRAC). The goal of these groups, in cooperation with academia and governmental agencies, was to act as a forum for the exchange of information on herbicide-resistance selection and to develop guidelines for managing resistance. Despite these efforts, herbicide resistance continued to increase. The introduction of glyphosate-resistant crops in the 1995 provided a brief respite from herbicide resistance, and farmers rapidly adopted this relatively simple and reliable weed management system based on glyphosate. There were many warnings from academia and some companies that the glyphosate-resistant crop system was not sustainable, but this advice was not heeded. The selection of glyphosate resistant weeds dramatically changed weed management and renewed emphasis on herbicide resistance management. To date, the lesson learned from our experience with herbicide resistance is that no herbicide is invulnerable to selecting for resistant biotypes, and that over-reliance on a weed management system based solely on herbicides is not sustainable. Hopefully we have learned that a diverse weed management program that combines multiple methods is the only system that will work for the long term.

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Fuerst, E. Patrick, Charles J. Arntzen, Klaus Pfister et Donald Penner. « Herbicide Cross-Resistance in Triazine-Resistant Biotypes of Four Species ». Weed Science 34, n^o 3 (mai 1986) : 344–53. http://dx.doi.org/10.1017/s0043174500066960.

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The cross-resistance of triazine-resistant biotypes of smooth pigweed (Amaranthus hybridusL. # AMACH), common lambsquarters (Chenopodium albumL. # CHEAL), common groundsel (Senecio vulgarisL. # SENVU), and the crop canola (Brassica napusL. var. Atratower) to a selection of herbicides was evaluated at both the whole plant and chloroplast level. The triazine-resistant biotypes of all four species showed a similar pattern of cross-resistance, suggesting that a similar mutation had occurred in each species. The four triazine-resistant biotypes were resistant to injury from atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine], bromacil [5-bromo-6-methyl-3-(1-methylpropyl)-2,4-(1H,3H)pyrimidinedione], and pyrazon [5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone] and were slightly resistant to buthidazole {3-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-4-hydroxy-1-methyl-2-imidazolidinone}. The triazine-resistant biotypes were more sensitive to dinoseb [2-(1-methylpropyl)-4,6-dinitrophenol]. Triazine-resistant smooth pigweed showed resistance to cyanazine {2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl] amino]-2-methylpropanenitrile} and metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] with slight resistance to linuron [N′-(3,4-dichlorophenyl)-N-methoxy-N-methylurea] and desmedipham {ethyl [3-[[(phenylamino)carbony] oxy] phenyl] carbamate}. There was little or no resistance to diuron [N′-(3,4-dichlorophenyl)-N,N-dimethylurea], bromoxynil (3,5-dibromo-4-hydroxybenzonitrile), bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide], or dicamba (3,6-dichloro-2-methoxybenzoic acid). Parallel studies at the chloroplast level indicated that the degree of resistance to inhibition of photosynthetic electron transport was highly correlated with the degree of resistance to herbicidal injury. This correlation indicates that atrazine, cyanazine, metribuzin, pyrazon, bromacil, linuron, desmedipham, and buthidazole cause plant injury by inhibition of photosynthesis. This correlation also indicates that triazine resistance and cross-resistance at the whole plant level is due to decreased sensitivity at the level of photosynthetic electron transport. Cross-resistance to numerous additional herbicides was evaluated on isolated chloroplast thylakoid membranes and these results are discussed.14C-atrazine was displaced from thylakoid membranes by several herbicides, indicating that these herbicides compete for a common binding site.

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Brooks, David R., Suzanne J. Clark, Joe N. Perry, David A. Bohan, Gillian T. Champion, Les G. Firbank, Alison J. Haughton, Cathy Hawes, Matthew S. Heard et Ian P. Woiwod. « Invertebrate biodiversity in maize following withdrawal of triazine herbicides ». Proceedings of the Royal Society B : Biological Sciences 272, n^o 1571 (28 juin 2005) : 1497–502. http://dx.doi.org/10.1098/rspb.2005.3102.

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Responses of key invertebrates within Farm Scale Evaluations (FSEs) of maize reflected advantageous effects for weeds under genetically modified herbicide-tolerant (GMHT) management. Triazine herbicides constitute the main weed control in current conventional systems, but will be withdrawn under future EU guidelines. Here, we reappraise FSE data to predict effects of this withdrawal on invertebrate biodiversity under alternative management scenarios. Invertebrate indicators showed remarkably consistent and sensitive responses to weed abundance. Their numbers were consistently reduced by atrazine used prior to seedling emergence, but at reduced levels compared to similar observations for weeds. Large treatment effects were, therefore, maintained for invertebrates when comparing other conventional herbicide treatments with GMHT, despite reduced differences in weed abundance. In particular, benefits of GMHT remained under comparisons with best estimates of future conventional management without triazines. Pitfall trapped Collembola, seed-feeding carabids and a linyphiid spider followed closely trends for weeds and may, therefore, prove useful for modelling wider biodiversity effects of herbicides. Weaker responses to triazines applied later in the season, at times closer to the activity and capture of invertebrates, suggest an absence of substantial direct effects. Contrary responses for some suction-sampled Collembola and the carabid Loricera pilicornis were probably caused by a direct deleterious effect of triazines.

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Gressel, Jonathan, et Lee A. Segel. « Negative Cross Resistance ; a Possible Key to Atrazine Resistance Management : A Call for Whole Plant Data ». Zeitschrift für Naturforschung C 45, n^o 5 (1 mai 1990) : 470–73. http://dx.doi.org/10.1515/znc-1990-0528.

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Many photosystem II inhibiting herbicides still inhibit this process in triazine-resistant plants; i.e. they have no cross resistance with atrazine. Five- to twenty-fold lower concentrations of phenolic type herbicidcs and 5-fold less of the active ingredient of pyridate and half as much ioxynil are required to inhibit thylakoid PS II in atrazine-resistant biotypes than in sensitive biotypes; i.e., they even show “negative cross resistance”. Negative cross resistance may be the major reason that atrazine resistance did not evolve where herbicide mixtures were used, when the mixed herbicide (usually a non-PS II inhibiting acetanilide) also controlled triazine-sensitivc weeds. Mathematical modeling in principle allows quantification of the very low field levels of herbicides possessing negative cross resistance that could be mixed with atrazine that would stop or delay the evolution of resistant populations without affecting the maize crop. There are few available actual dose response curves of atrazine-resistant vs. susceptible weeds at the whole plant level for herbicidcs exerting negative cross resistance. Thus, “real situation” modeling cannot be done. Data acquisition is called for so that the model can be extrapolated from the thylakoid to the field.

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Elezovic, Ibrahim, Dragana Bozic et Sava Vrbnicanin. « Weed resistance to herbicides states : Causes and possibilities of preventive resistance ». Pesticidi 18, n^o 1 (2003) : 5–21. http://dx.doi.org/10.2298/pif0301005e.

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Resistance occurs as a result of heritable changes to biochemical processes that enable plant survival when treated with a herbicide. Resistance can result from changes to the herbicides target site such that binding of the herbicide is reduced, or over-expression of the target site may occur. Alternatively, there may be a reduction in the amount of herbicide that reaches the target enzyme through detoxication, sequestration, or reduced absorption of herbicide. Finally, the plant may survive through the ability to protect plant metabolism from toxic compounds produced as a consequence of herbicide action. Herbicide-resistant weeds were predicted shortly after the introduction of herbicides. During the 1970s, many, additional important weed species (e.g., Amaranthus spp., Chennpodium spp., Erigeron canadensis Kochia scoparia, Solanum nigrum, Panicum crus-galli, Senecio vulgaris, Poa annua) were reported to be resistant to triazine herbicides and several other herbicides. Over the last 10 years and now ALS-herbicide-resistant weeds account for the greatest number of resistant species and probably the largest area affected by resistance. In contrast to triazine resistance target-site-based resistance to the ALS-inhibiting herbicides can be conferred by a number of different point mutations. Differences occur in target-site cross-resistance among the different chemical classes of herbicides that inhibit ALS. The differences are related to particular amino acid substitutions that occur within the binding region. Indeed, six different substitutions of Ala, Arg, Glu, Leu, Ser, or Tri for Pro 173 have been observed in different weed populations.

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Burnet, Michael W. M., Orville B. Hildebrand, Joseph A. M. Holtum et Stephen B. Powles. « Amitrole, Triazine, Substituted Urea, and Metribuzin Resistance in a Biotype of Rigid Ryegrass (Lolium rigidum) ». Weed Science 39, n^o 3 (septembre 1991) : 317–23. http://dx.doi.org/10.1017/s0043174500072994.

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A biotype of rigid ryegrass (Lolium rigidum G. ♯ LOLRI) has become resistant to amitrole and atrazine after 10 yr of exposure to a mixture of these herbicides. Resistance has also been demonstrated to the chloro-s-triazines: simazine, cyanazine, propazine; the methylthios-triazines: ametryn, prometryn; the substituted ureas: chlortoluron, isoproturon, metoxuron, diuron, fluometuron, methazole; and the triazinone herbicide metribuzin. The biotype remains susceptible to chlorsulfuron, metsulfuron, sulfometuron, sethoxydim, diclofop, fluazifop, glyphosate, carbetamide, and oxyfluorfen. Inhibition of oxygen evolution by atrazine, diuron, and metribuzin was similar in thylakoids isolated from both resistant and susceptible biotypes. Therefore, resistance to the photosystem II inhibitors is not caused by an alteration of the target site of these herbicides. Resistant plants treated with a 3-h pulse of 0.12 mM chlortoluron recover photosynthetic activity more rapidly than susceptible plants. This suggests that the basis for resistance is enhanced metabolism or sequestration of the herbicide within the leaf.

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Powles, Stephen B., et Peter D. Howat. « Herbicide-resistant Weeds in Australia ». Weed Technology 4, n^o 1 (mars 1990) : 178–85. http://dx.doi.org/10.1017/s0890037x00025203.

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This review considers the development of herbicide-resistant weed biotypes in Australia. Biotypes of the important annual weed species, capeweed, wall barley, and hare barley are resistant to the bipyridylium herbicides paraquat and diquat. These resistant biotypes developed on a small number of alfalfa fields that have a long history of paraquat and diquat use within a distinct geographical area in central western Victoria. The resistant biotypes are controlled by alternative herbicides and pose little practical concern. Some populations of wild oat are resistant to the methyl ester of diclofop. Of greatest concern is the development of cross resistance in biotypes of rigid ryegrass to aryloxyphenoxypropionate, cyclohexanedione, sulfonylurea, and dinitroaniline herbicides. The cross-resistant rigid ryegrass infests crops and pastures at widely divergent locales throughout the cropping zones of southern Australia. The options for control of cross-resistant rigid ryegrass by herbicides are limited. A biotype of rigid ryegrass on railway tracks treated for 10 yr with amitrole plus atrazine has resistance to amitrole and atrazine and other triazine, triazinone, and phenylurea herbicides. Management tactics for cross resistance are discussed.

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Ghanizadeh, Hossein, et Kerry C. Harrington. « Ecological Evidence for the Fitness Trade-Off in Triazine Resistant Chenopodium Album L. : Can We Exploit the Cost of Resistance ? » Agronomy 9, n^o 9 (9 septembre 2019) : 523. http://dx.doi.org/10.3390/agronomy9090523.

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The alleles responsible for herbicide resistance in weeds can result in a fitness cost within affected plants. Over 200 cases of resistance to triazine herbicides have been confirmed in a wide range of weed species globally. In New Zealand, Chenopodium album L. was the first species reported as resistant to triazines. Several studies have already shown that triazine resistance in weeds is associated with fitness costs. Our current study provides further information about fitness penalties caused by triazine resistance during the vegetative growth phase of C. album. Triazine-resistant phenotypes produced less biomass and were shorter than susceptible ones prior to the onset of flowering. At an early stage of growth, triazine-resistant plants had lower photosynthetic efficacy and growth rates than susceptible plants, indicated by lower net assimilation rate (NAR) and relative growth rate (RGR), respectively. However, at a later stage of growth, the resistant plants had greater RGR values than susceptible phenotypes, though there were no significant differences in NAR between triazine-resistant and susceptible plants at this later stage. The triazine-resistant plants had less capacity for vegetative growth than susceptible plants during competition with wheat, indicating less ability to capture resources by triazine-resistant plants under competition. Overall, this study has revealed that the triazine resistance allele caused a substantial fitness cost to C. album only at the early phase of vegetative growth stage; thus, the use of crop competition to try managing triazine-resistant C. album plants should occur during this early phase.

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Salaković, Benjamin, Strahinja Kovačević, Milica Karadžić Banjac, Sanja Podunavac-Kuzmanović, Lidija Jevrić, Ivana Pajčin et Jovana Grahovac. « New Perspective on Comparative Chemometric and Molecular Modeling of Antifungal Activity and Herbicidal Potential of Alkyl and Cycloalkyl s-Triazine Derivatives ». Processes 11, n^o 2 (22 janvier 2023) : 358. http://dx.doi.org/10.3390/pr11020358.

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The contamination of the environment by pesticides is becoming a burning issue in many countries in the World. Development, design, and synthesis of new eco-friendly pesticides and modification of existing ones in order to improve their efficacy with the lowest impact on the environment are two main future possibilities in crop protection and the provision of sufficient food for the growing world population. The present study is focused on the comparative analysis of a series of eight symmetrical triazine derivatives, as potential herbicide candidates with acyclic (alkyl) and cyclic (cycloalkyl) substituents, in terms of their antifungal activity towards Aspergillus flavus as an opportunistic fungal pathogenic microorganism responsible for frequent contaminations of crops with aflatoxin, and in terms of their potential application as herbicides in maize, common wheat, barley, and rice crops. The applied methods include the chemometric pattern recognition method (hierarchical cluster analysis), experimental microbiological analysis of antifungal activity (agar well-diffusion method), and molecular docking of the triazines in the corresponding enzymes. The main findings of the conducted study indicate the significant antifungal activity of the studied triazine derivatives towards A. flavus, particularly the compounds with acyclic substituents; five out of eight studied triazines could be applied as systematic herbicides, while the other three triazines could be used as contact herbicides; the compounds with acyclic substituents could be more suitable for application for various crops protection than triazines with cyclic substituents.

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Vencill, William K., et Chester L. Foy. « Distribution of Triazine-Resistant Smooth Pigweed (Amaranthus hybridus) and Common Lambsquarters (Chenopodium album) in Virginia ». Weed Science 36, n^o 4 (juillet 1988) : 497–99. http://dx.doi.org/10.1017/s0043174500075251.

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The distribution pattern ofs-triazine-resistant biotypes of common lambsquarters (Chenopodium albumL. #3CHEAL) and smooth pigweed (Amaranthus hybridusL. # AMACH) in Virginia was determined. Seeds were collected from suspected triazine-resistant biotypes of both species. Triazine resistance was confirmed by measuring chlorophyll fluorescence in the presence of atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine]. Greenhouse bioassay with whole-plant material and a sinking leaf disc assay were also performed as further confirmation of triazine resistance. Triazine-resistant smooth pigweed was confirmed in 19 counties and common lambsquarters in eight counties in Virginia. Triazine-resistant smooth pigweed and common lambsquarters were located mostly in the northern and southwestern highlands of the state where there has been a long history of triazine use in no-till corn (Zea maysL.) production.S-triazine-resistant biotypes were also cross-resistant to other representatives-triazine andas-triazine herbicides but susceptible to the substituted urea herbicide diuron [N′-(3,4-dichlorophenyl)-N,N-dimethylurea].

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Wu, Lei, Yu-Cheng Gu, Yong-Hong Li, Sha Zhou, Zhong-Wen Wang et Zheng-Ming Li. « Synthesis, Herbicidal Activity, Crop Safety and Soil Degradation of Pyrimidine- and Triazine-Substituted Chlorsulfuron Derivatives ». Molecules 27, n^o 7 (6 avril 2022) : 2362. http://dx.doi.org/10.3390/molecules27072362.

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Chlrosulfuron, a classical sulfonylurea herbicide that exhibits good safety for wheat but causes a certain degree of damage to subsequent corn in a wheat–corn rotation mode, has been suspended field application in China since 2014. Our previous study found that diethylamino-substituted chlorsulfuron derivatives accelerated the degradation rate in soil. In order to obtain sulfonylurea herbicides with good crop safety for both wheat and corn, while maintaining high herbicidal activities, a series of pyrimidine- and triazine-based diethylamino-substituted chlorsulfuron derivatives (W102–W111) were systematically evaluated. The structures of the synthesized compounds were confirmed with 1H NMR, 13C NMR, and HRMS. The preliminary biological assay results indicate that the 4,6-disubstituted pyrimidine and triazine derivatives could maintain high herbicidal activity. It was found that the synthesized compounds could accelerate degradation rates, both in acidic and alkaline soil. Especially, in alkaline soil, the degradation rate of the target compounds accelerated more than 22-fold compared to chlorsulfuron. Moreover, most chlorsulfuron analogs exhibited good crop safety for both wheat and corn at high dosages. This study provided a reference for the further design of new sulfonylurea herbicides with high herbicidal activity, fast degradation rates, and high crop safety.

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Davies, PE, LSJ Cook et JL Barton. « Triazine herbicide contamination of Tasmanian streams : Sources, concentrations and effects on biota ». Marine and Freshwater Research 45, n^o 2 (1994) : 209. http://dx.doi.org/10.1071/mf9940209.

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Concentrations of the triazine herbicides atrazine, simazine, cyanazine, metribuzin and propazine were determined in streams draining forestry and agricultural catchments in Tasmania, Australia, between 1989 and 1992. Atrazine and simazine were used extensively by the forestry industry in a winter spraying programme, and applications of the other herbicides occurred in cropped agricultural catchments during spring and summer. Of 29 streams sampled intensively for triazines, 20 contained detectable residues. Median contaminations over all samples were 2.85, 1.05, <0.05, <0.05 and <0.05 �g L-1 for atrazine, simazine, cyanazine, metribuzin and propazine, respectively. All herbicide concentrations ranged over several orders of magnitude up to 53 mg L-1, with atrazine and simazine having significantly higher concentrations than the others. Atrazine concentrations were examined in streams draining forestry plantations for periods of up to two years. A decline in concentration was observed with time, but this was strongly influenced by rainfall events. Atrazine contamination from single spraying events persisted at a low level for up to 16 months. Contamination of Big Creek with atrazine to 22�g L-1 after aerial spraying led to an increase in stream invertebrate drift only on the day of spraying and to a short-term increase in movement of brown trout. On examination of biological effects of triazines in surface waters reported in the literature, it was concluded that the observed frequent contamination of Tasmanian streams with triazines may cause occasional minor short-term disturbance to stream communities.

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Hirschberg, Joseph, Nir Ohad, Iris Pecker et Ana Rahat. « Isolation and Characterization of Herbicide Resistant Mutants in the Cyanobacterium Synechococcus R2 ». Zeitschrift für Naturforschung C 42, n^o 6 (1 juin 1987) : 758–61. http://dx.doi.org/10.1515/znc-1987-0619.

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A variety of mutants which are resistant to triazine - and urea - classes of herbicides have been isolated in the cyanobacterium Synechococcus R2. All the mutants that have been analyzed, show some cross-resistance to different herbicides suggesting that these herbicides share a common binding site in photosystem II. Three psbA genes have been identified in Synechococcus R2. The psbA-copy I gene was cloned from three mutants and used in DNA-mediated genetic transformation. It was found that in all three mutants this gene could transfer the mutation for herbicide resistance indicating that this gene codes for the herbicide resistant protein.

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Teasdale, John R. « Avoidance of Herbicide Injury by Placement between Rows of Polyethylene Mulch ». HortScience 20, n^o 5 (octobre 1985) : 871–72. http://dx.doi.org/10.21273/hortsci.20.5.871.

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Abstract Several herbicides which usually are toxic to muskmelon (Cucumis melo L.) did not reduce melon yield when applied to soil between crop rows mulched with black polyethylene. These herbicides include metolachlor, alachlor, oryzalin, linuron, acifluorfen, metribuzin, and paraquat. However, oxyfluorfen and atrazine cause severe injury and reduced yield in some instances. Herbicide injury appeared to result from movement of herbicide to plants by rainfall runoff or by volatilization rather than by root uptake from the treated area. Chemical names used: 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid (acifluorfen); 2-chloro-N-(2,6-diethylphenyl)-N-methoxymethyl)acetamide (alachlor); N’-(3,4-dichlorophenyl)-N-methoxy-N-methylurea (linuron); 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide (metolachlor); 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin); 1,1′-dimethyl-4,4′-bipyridinium salts (paraquat); (4-amino-6-[1,1-dimethylethyl]-3-[methylthio]-1,2,4- -triazin-5 [4H]-one) (metribuzin); 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene (oxyfluorfen); 6-chloro-N-ethyl-N’-(1-methylethyl)-1,3,5-triazine-2,4-diamine (atrazine).

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Warwick, S. I., et L. D. Black. « Relative fitnes of herbicide-resistant and susceptible biotypes of weeds ». Comptes rendus 75, n^o 4 (12 avril 2005) : 37–49. http://dx.doi.org/10.7202/706070ar.

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In recent years, there has been a rapid increase in the number of reported cases of herbicide-resistant weed species (over 100), as well as an increase in the types of herbicides to which resistance has evolved. This paper reviews evidence for differential fitness of herbicide-resistant and susceptible biotypes. Fitness estimates are required to produce reliable population models. Fitness measures describe the potential evolutionary success of a genotype based on survival, competitive ability and ultimately reproductive success. Differences in relative fitness between resistant and susceptible biotypes are usually inferred from measures of relative plant productivity or competitiveness. For triazine-resistant weed species, studies have indicated that resistant plants were generally less fit than susceptible plants, although exceptions did exist. Although less data are available on the fitness of plants resistant to non-triazine herbicides, information is summarized for sulfonylureas, substituted ureas, dinitroanilines, paraquat, diclofop, and organic arsenicals. No consistent differences in relative fitness were observed for non-triazine resistant and susceptible biotypes. In general, studies have indicated that the relative fitness of susceptible and resistant biotypes of a single species depends upon biological conditions, including genotype and population variation, intra- and inter-biotype competition, and environmental conditions such as temperature, light quality, and management practices. Future needs for relative fitness studies are discussed.

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Mueller, Thomas C., Scott A. Senseman, Kathy H. Carson et Audie S. Sciumbato. « Stability and Recovery of Triazine and Chloroacetamide Herbicides from pH Adjusted Water Samples by Using Empore Solid-Phase Extraction Disks and Gas Chromatography with Ion Trap Mass Spectrometry ». Journal of AOAC INTERNATIONAL 84, n^o 4 (1 juillet 2001) : 1070–73. http://dx.doi.org/10.1093/jaoac/84.4.1070.

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Abstract Empore disks were used to successfully extract herbicide residues from a difficult-to-analyze surface water source and deionized water. Herbicide recoveries were lower in surface water at 7, 14, or 21 days after fortification and storage at 4°C, presumably due to chemical sorption onto precipitated organic particulates. The addition of acid to the samples, as recommended in EPA Method 525.2, did not affect recoveries of alachlor and metolachlor, but reduced recoveries of atrazine, simazine, and cyanazine. Treatment of water samples with sodium hypochlorite did not affect alachlor or metolachlor recoveries, but greatly reduced the recovery of all triazine herbicides. This indicates that addition of acid or sodium hypochlorite to water samples may be detrimental to triazine analysis.

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Nasrollahpour, Atefe, et Seyyed Ershad Moradi. « A Simple Vortex-Assisted Magnetic Dispersive Solid Phase Microextraction System for Preconcentration and Separation of Triazine Herbicides from Environmental Water and Vegetable Samples Using Fe3O4@MIL-100(Fe) Sorbent ». Journal of AOAC INTERNATIONAL 101, n^o 5 (1 septembre 2018) : 1639–46. http://dx.doi.org/10.5740/jaoacint.17-0374.

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Abstract A vortex-assisted magnetic dispersive solid phase microextraction coupled with high-performance liquid chromatography has been developed for the extraction and determination of triazine herbicides by using magnetic metal organic frameworks [Fe3O4@MIL-100(Fe)] in environmental water and vegetable samples. The Fe3O4@MIL-100(Fe) composite has been characterized by using X-ray diffraction spectroscopy, tunneling electron microscopy, thermogravimetric measurement, and Brunauer-Emmett-Teller analysis. The method is based on the sorption of triazine herbicides on Fe3O4@MIL-100(Fe) because of the complex formation between iron oxide nanoparticles and triazine herbicides beside π-π interactions between organic parts of Fe3O4@MIL-100(Fe) and triazine herbicides. The experimental parameters for the preconcentration of triazine herbicides, such as the type and volume of the eluent, pH, time of the sorption and desorption, and the amount of the sorbent, were optimized. Under the optimized conditions, the method was linear over the concentration range of 0.0061 to 70 ng/mL for each triazine herbicide, and the correlation coefficients ranged from 0.9988 to 0.9997. The limit of detection of the method at a signal-to-noise ratio of 3 was 2.0 to 5.3 ng/mL. The relative standard deviations for inter- and intraday assays were in the range of 5.8 to 10.2% and 3.8 to 6.3%, respectively.

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Hirschberg, Joseph, Nir Ohad, Iris Pecker et Ana Rahat. « Isolation and Characterization of Herbicide Resistant Mutants in the Cyanobacterium Synechococcus R2 ». Zeitschrift für Naturforschung C 42, n^o 7-8 (1 août 1987) : 758–61. http://dx.doi.org/10.1515/znc-1987-7-802.

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Department of Genetics, The Hebrew University of Jerusalem. Jerusalem. A variety of mutants which are resistant to triazine - and urea - classes of herbicides have been isolated in the cyanobacterium Synechococcus R2. All the mutants that have been analyzed, show some cross-resistance to different herbicides suggesting that these herbicides share a common binding site in photosystem II. Three psbA genes have been identified in Synechococcus R2. The psbA-copy I gene was cloned from three mutants and used in DNA-mediated genetic transformation. It was found that in all three mutants this gene could transfer the mutation for herbicide resistance indicating that this gene codes for the herbicide resistant protein.

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Holt, Jodie S. « History of Identification of Herbicide-Resistant Weeds ». Weed Technology 6, n^o 3 (septembre 1992) : 615–20. http://dx.doi.org/10.1017/s0890037x00035910.

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At least 57 weed species, including both dicots and monocots, have been reported to have biotypes selected for resistance to the triazine herbicides. In addition, at least 47 species have been reported to have biotypes resistant to one or more of 14 other herbicides or herbicide families. These herbicides include the aryloxyphenoxypropionics, bipyridiliums, dinitroanilines, phenoxys, substituted areas, and sulfonylureas, with two or more resistant biotypes each, as well as several other herbicides in which resistance is less well documented. Although evolved resistance presents a serious problem for chemical weed control, it has also offered new potential for transferring herbicide resistance to crop species. Mechanisms of resistance that are due to single or a few genes have become the focus of biotechnology, as the probability of their successful transfer to crop species is high.

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Steinegger, D. H., R. C. Shearman et L. Finke. « Veronica repens Establishment with Herbicides and Activated Charcoal ». HortScience 22, n^o 4 (août 1987) : 609–11. http://dx.doi.org/10.21273/hortsci.22.4.609.

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Abstract Veronica repens was evaluated in a field study comparing herbicide effects on ground cover establishment. Herbicides were applied 1 day before ground covers were transplanted. Ground cover transplant root systems were either dipped or not dipped in an activated charcoal slurry prior to planting. There was a significant interaction between herbicide and charcoal treatment. Dichlobenil, chlorsulfuron, and simazine caused significant injury and reduced surface coverage. Transplants dipped in activated charcoal and treated with dichlobenil or chlorsulfuron had as much as three times less injury and produced 24% greater surface coverage than those without activated charcoal. DCPA, oxadiazon, and trifluralin caused little herbicide injury or ground cover stand reduction, and activated charcoal preconditioning did not influence their responses. These results indicate a broad herbicide range could be used with the activated charcoal root system dip procedure during Veronica repens establishment. Chemical names used: dimethyl tetrachloroterephthalate (DCPA), 2,6-dichlorobenzonitrile (dichlobenil); 2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]benzenesulfonamide (chlorsulfuron); 3-[2,4-dichloro-5-(1-methyle-thoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2(3H)-one (oxadiazon); 6-chloro-N, N’-diethyl-1,3,5-triazine-2,4-diamine (simazine); α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin).

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Gardner, Gary, James R. Sanborn et John R. Goss. « N-Alkylaryltriazine Herbicides : A Possible Link Between Triazines and Phenylureas ». Weed Science 35, n^o 6 (novembre 1987) : 763–69. http://dx.doi.org/10.1017/s0043174500079303.

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A comparison of the structure of the α-methylbenzyl analogue (MBAT) of atrazine with the Photosystem II herbicides atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and diuron [N′-(3,4-dichlorophenyl)-N,N-dimethylurea] suggested thatN-alkylbenzyltriazines may be a structural bridge between the triazines and the phenylureas. In the phenylureas, the addition of chlorines at the meta and/or para positions produces a marked increase in activity. Chloro-substituted derivatives of MBAT were synthesized to determine whether this structure-activity relationship also applies to the alkylaryltriazines. Addition of a chlorine to MBAT at the 4-position (CMBAT) caused a substantial increase in intrinsic activity, and a second chlorine at the 3-position (DCMBAT) caused a further increase. In direct comparisons, DCMBAT was more active in vitro than terbuthylazine [6-chloro-N-ethyl-N′-(1,1-dimethylethyl)-1,3,5-triazine-2,4-diamine], the most active chlorotriazine, and was also more active than diruon. The effects of DCMBAT were also measured on triazine-resistant pigweed (Amaranthus hybridusL. # AMACH) both in vivo and in vitro. The activity of this compound in triazine-resistant chloroplasts was intermediate between that of atrazine and diruon both in inhibition of photosynthetic electron transport and in competition for diuron binding sites, with half-maximal values falling in the micromolar range. Whole plant phytotoxicity of DCMBAT on triazine-resistant pigweed was also intermediate between that of diuron and atrazine. Since DCMBAT is a triazine with biological properties similar to that of a urea, we conclude that in a functional as well as structural sense, DCMBAT is a herbicide that is a hybrid between a triazine and a urea.

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Feucht, James. « Herbicide Injuries to Trees : Symptoms and Solutions ». Arboriculture & ; Urban Forestry 14, n^o 9 (1 septembre 1988) : 215–19. http://dx.doi.org/10.48044/jauf.1988.052.

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Arborists are frequently called upon to diagnose injuries to trees that may be the result of herbicides incorrectly or inappropriately applied by the client or an adjoining neighbor. In many cases, an arborist is blamed for causing the damages to a client's trees. Arborists need to recognize herbicide symptoms and mimicking symptoms, as well as learn appropriate corrective measures. The presentation compares symptoms caused by herbicides such as 2, 4-D, banvel, and triazine compounds with mimicking symptoms for nonherbicide causes. Foliage and soil residue of herbicide contaminants is documented with laboratory tests showing the minimum residues required to cause damage to various trees from soil sterilants such as bromacil, prometon and tebuthiuron.

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Parks, Robert J., William S. Curran, Gregory W. Roth, Nathan L. Hartwig et Dennis D. Calvin. « Herbicide Susceptibility and Biological Fitness of Triazine-Resistant and Susceptible Common Lambsquarters (Chenopodium album) ». Weed Science 44, n^o 3 (septembre 1996) : 517–22. http://dx.doi.org/10.1017/s0043174500094273.

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Biological fitness and negative cross-resistance to other herbicides may be an important factor in managing triazine-resistant common lambsquarters. Greenhouse experiments examined the sensitivity of a resistant and a susceptible biotype to foliarly-applied bentazon, bromoxynil, dicamba, pyridate, and thifensulfuron. The noncompetitive vigor of triazine-resistant and susceptible common lambsquarters also was compared by growing plants in individual containers and harvesting them periodically throughout their vegetative period and at reproductive maturity. In the herbicide susceptibility study, 11 kg ai ha−1atrazine had no effect on the growth of the resistant biotype, while it reduced susceptible common lambsquarters’ biomass by up to 68%. Estimated I50values indicated the resistant biotype exhibited between 36 and 79% greater susceptibility to bentazon, bromoxynil, dicamba, and pyridate than did the susceptible one, while both responded similarly to thifensulfuron. In growth studies, the susceptible biotype achieved greater height, leaf area, and plant dry weight than the resistant population for the majority of harvest dates; however, values equalized between biotypes as the plants reached maturity. These experiments suggest that alternative management programs that exploit reduced fitness and increased herbicide susceptibility in triazine-resistant common lambsquarters could be developed. However, further studies are needed to determine whether these results have application for the management of triazine-resistant weeds in the field.

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Topp, Edward, Walter M. Mulbry, Hong Zhu, Sarah M. Nour et Diane Cuppels. « Characterization of S-Triazine Herbicide Metabolism by a Nocardioides sp. Isolated from Agricultural Soils ». Applied and Environmental Microbiology 66, n^o 8 (1 août 2000) : 3134–41. http://dx.doi.org/10.1128/aem.66.8.3134-3141.2000.

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ABSTRACT Atrazine, a herbicide widely used in corn production, is a frequently detected groundwater contaminant. Nine gram-positive bacterial strains able to use this herbicide as a sole source of nitrogen were isolated from four farms in central Canada. The strains were divided into two groups based on repetitive extragenic palindromic (rep)-PCR genomic fingerprinting with ERIC and BOXA1R primers. Based on 16S ribosomal DNA sequence analysis, both groups were identified as Nocardioides sp. strains. None of the isolates mineralized [ring-U-14C]atrazine. There was no hybridization to genomic DNA from these strains usingatzABC cloned from Pseudomonas sp. strain ADP or trzA cloned from Rhodococcus corallinus. S-Triazine degradation was studied in detail inNocardioides sp. strain C190. Oxygen was not required for atrazine degradation by whole cells or cell extracts. Based on high-pressure liquid chromatography and mass spectrometric analyses of products formed from atrazine in incubations of whole cells with H2 18O, sequential hydrolytic reactions converted atrazine to hydroxyatrazine and then to the end productN-ethylammelide. Isopropylamine, the putative product of the second hydrolytic reaction, supported growth as the sole carbon and nitrogen source. The triazine hydrolase from strain C190 was isolated and purified and found to have a Km for atrazine of 25 μM and a V max of 31 μmol/min/mg of protein. The subunit molecular mass of the protein was 52 kDa. Atrazine hydrolysis was not inhibited by 500 μM EDTA but was inhibited by 100 μM Mg, Cu, Co, or Zn. Whole cells and purified triazine hydrolase converted a range of chlorine or methylthio-substituted herbicides to the corresponding hydroxy derivatives. In summary, an atrazine-metabolizingNocardioides sp. widely distributed in agricultural soils degrades a range of s-triazine herbicides by means of a novel s-triazine hydrolase.

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Birschbach, Eric D., Mark G. Myers et R. Gordon Harvey. « Triazine-Resistant Smooth Pigweed (Amaranthus hybridus) Control in Field Corn (Zea maysL.) ». Weed Technology 7, n^o 2 (juin 1993) : 431–36. http://dx.doi.org/10.1017/s0890037x00027846.

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Studies were conducted for 3 yr to evaluate herbicides and herbicide combinations for triazine-resistant smooth pigweed (TR-AMACH) control in field corn. Of the PRE treatments, combinations of atrazine plus acetochlor, metolachlor plus dicamba, and atrazine plus alachlor provided the most complete control of this weed (77 to 81%). The best early postemergence (EP) combination was pendimethalin plus atrazine plus dicamba (93% control). Pyridate plus atrazine applied POST provided a four-site average of 98% control. The most effective sequential herbicide treatments consisted of either metolachlor or pendimethalin PRE followed by POST treatments containing either pyridate, thifensulfuron, bromoxynil, or dicamba.

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MacLennan, Paul, Elizabeth Delzell, Nalini Sathiakumar et Susan Myers. « Mortality Among Triazine Herbicide Manufacturing Workers ». Journal of Toxicology and Environmental Health, Part A 66, n^o 6 (janvier 2003) : 501–17. http://dx.doi.org/10.1080/15287390306356.

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Pham, T. T., B. Rondeau, H. Sabik, S. Proulx et D. Cossa. « Lake Ontario : the predominant source of triazine herbicides in the St. Lawrence River ». Canadian Journal of Fisheries and Aquatic Sciences 57, S1 (14 mars 2000) : 78–85. http://dx.doi.org/10.1139/f99-233.

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To estimate triazine herbicide concentrations and sources in the St. Lawrence River, water samples were collected at its two major inlets (from the Great Lakes, Cornwall station, and from the Ottawa River, Carillon station) and at the outlet (Quebec City station) of the fluvial section. Sampling was carried out over an 18-month period between 1995 and 1996. Triazines were detected only in the dissolved phase at concentrations ranging from 2 to 91, from <0.4 to 15, and from <0.4 to 13 ng·L-1 for atrazine, cyanazine, and simazine, respectively. Dilution models show that, despite the presence of sporadically high concentrations of herbicides in St. Lawrence tributaries during periods of their application, loading from the tributaries is minor. Mass balance calculations show that Lake Ontario is clearly the main source of triazines (~90%) to the St. Lawrence River. During the 1995-1996 hydrological year, Lake Ontario contributed 15.1 × 103 of the 16.6 × 103 kg of atrazine outflowing the St. Lawrence River to the estuary. The difference (1.5 × 103 kg·year-1) can be attributed to tributaries in Quebec, which represent 0.75% of the amount of atrazine spread on farmlands. There is no evidence of the degradation of triazine compounds during their transit time in the river.

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Stamper, David M., Mark Radosevich, Kevin B. Hallberg, Samuel J. Traina et Olli H. Tuovinen. « Ralstonia basilensisM91-3, a denitrifying soil bacterium capable of usings-triazines as nitrogen sources ». Canadian Journal of Microbiology 48, n^o 12 (1 décembre 2002) : 1089–98. http://dx.doi.org/10.1139/w02-113.

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The purpose of this study was to characterize the phylogenetic and phenotypic traits of M91-3, a soil bacterium capable of mineralizing atrazine (2-chloro-4-N-isopropyl-6-N-ethyl-s-triazine). The isolate was identified as Ralstonia basilensis based on 99.5% homology of the 16S rRNA sequence and various chemotaxonomic data. The isolate used atrazine as the sole source of energy, carbon, and nitrogen. It could also use several other s-triazines as nitrogen sources. Ralstonia basilensis M91-3 was capable of denitrification, which was confirmed by gas chromatographic analysis of nitrous oxide under acetylene blockage conditions.Key words: atrazine biodegradation, denitrification, herbicide degrader, Ralstonia basilensis, triazine degradation.

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Peterson, Dallas E. « The Impact of Herbicide-Resistant Weeds on Kansas Agriculture ». Weed Technology 13, n^o 3 (septembre 1999) : 632–35. http://dx.doi.org/10.1017/s0890037x00046315.

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Herbicides are important components of weed management programs for most Kansas farmers. Monocropping systems and repeated use of the same or similar herbicides in some areas of the state have resulted in the development of herbicide-resistant weeds. The development of herbicide-resistant weed populations can have an immediate and a long-term effect on the cost, implementation, and effectiveness of weed control programs. In Kansas, resistance to triazine herbicides has been confirmed in kochia (Kochia scoparia), redroot pigweed, common waterhemp (Amaranthus rudis), Palmer amaranth (Amaranthus palmeri), and downy brome (Bromus tectorum) populations, and resistance to acetolactate synthase (ALS)-inhibiting herbicides has been confirmed in kochia, Russian thistle (Salsola kali), common waterhemp, Palmer amaranth, common cocklebur (Xanthium strumarium), shattercane (Sorghum bicolor), and common sunflower (Helianthus annum). The frequency and distribution of herbicide resistance varies among species. Producers who experience herbicide resistance problems adjust their weed control program accordingly. Producers that have not encountered an herbicide resistance problem tend to continue with a successful herbicide program until it fails. The recommended management strategies for herbicide-resistant weed populations include an integrated system of crop rotation, rotation of herbicide modes of action, tank-mixes of herbicides with different modes of action, and cultivation. The greatest direct cost to the producer occurs during the first year of poor weed control. The first response to an herbicide failure often is to reapply the same herbicide that has worked well previously. By the time the producer realizes that the treatment is not going to work, it usually is too late for any other remedial action. Consequently, the farmer experiences reduced crop production from weed competition, high herbicide costs, and a tremendous increase in the seed bank. The increase in seed bank may cost the farmer the most in the long run because the increased weed pressure often requires an intensified control program for several years.

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Wicks, Gail A., Alex R. Martin, Alan E. Haack et Garold W. Mahnken. « Control of Triazine-Resistant Kochia (Kochia scoparia) in Sorghum (Sorghum bicolor) ». Weed Technology 8, n^o 4 (décembre 1994) : 748–53. http://dx.doi.org/10.1017/s0890037x00028633.

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Herbicidal control of triazine-resistant (TR) kochia was evaluated in no-till grain sorghum. Herbicides were applied early preplant (EPP) or POST. In EPP experiments, herbicides plus nonionic surfactant at 0.25% v/v were applied 7, 2, or 0 wk before planting (WBP). Fluorochloridone at 0.8 kg ai/ha applied 7 or 2 WBP, pyridate at 1.0 kg ai/ha applied 2 WBP, and paraquat at 0.4 kg ai/ha applied 0 WBP controlled 94 to 99% of TR kochia; a prepackaged mixture of glyphosate plus 2,4-D at 0.3 plus 0.6 kg ae/ha and paraquat at 0.4 kg/ha applied 7 or 2 WBP controlled 71 to 82% of TR kochia; and 2,4-D ester at 0.6 kg ae/ha applied 2 WBP controlled 75% of TR kochia. Linuron at 0.8 kg ai/ha and atrazine at 2.2 kg ai/ha were ineffective. In the POST herbicide experiments, where paraquat plus metolachlor at 0.6 plus 1.7 kg ai/ha were applied 17 d before planting, various combinations and rates of bentazon plus atrazine, bromoxynil, and dicamba with adjuvants provided good control of TR kochia that was less than 8 cm tall.

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Derr, Jeffrey F., Joseph C. Neal et Prasanta C. Bhowmik. « Herbicide resistance in the nursery crop production and landscape maintenance industries ». Weed Technology 34, n^o 3 (juin 2020) : 437–46. http://dx.doi.org/10.1017/wet.2020.40.

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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.

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Foes, Matthew J., Lixin Liu, Gerald Vigue, Edward W. Stoller, Loyd M. Wax et Patrick J. Tranel. « A kochia (Kochia scoparia) biotype resistant to triazine and ALS-inhibiting herbicides ». Weed Science 47, n^o 1 (février 1999) : 20–27. http://dx.doi.org/10.1017/s0043174500090603.

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A kochia biotype from McDonough County, Illinois, was suspected to be resistant to both triazine and acetolactate synthase (ALS)-inhibiting herbicides. We performed greenhouse and laboratory experiments to confirm, quantify, and determine the molecular basis of multiple herbicide resistance in this biotype. Whole-plant phytotoxicity assays confirmed that the biotype was resistant to triazine (atrazine), imidazolinone (imazethapyr), and sulfonylurea (thifensulfuron and chlorsulfuron) herbicides. Relative to a susceptible kochia biotype, resistance to these herbicides ranged from 500- to > 28,000-fold. The kochia biotype from McDonough County also displayed high levels of resistance (2,000- to 9,000-fold) to ALS-inhibiting herbicides in in vivo ALS enzyme assays, indicating that resistance to these herbicides was site-of-action mediated. Results from chlorophyll fluorescence assays indicated that triazine resistance was also site-of-action mediated. Foliar applications of atrazine had little or no effect on photosynthesis in the resistant biotype, even when atrazine concentrations were 108-fold higher than needed to inhibit photosynthesis in the susceptible biotype. A region of the gene encoding the D1 protein of photosystem II and all of the open reading frame of the gene encoding ALS were sequenced and compared between the resistant and susceptible biotypes. Resistance to triazine and ALS-inhibiting herbicides in the kochia biotype from McDonough County was conferred by, respectively, a glycine for serine substitution at residue 264 of the D1 protein and a leucine for tryptophan substitution at residue 570 of ALS.

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Robinson, D. E., J. T. O’Donovan, M. P. Sharma, D. J. Doohan et R. Figueroa. « The biology of Canadian weeds. 123. Senecio vulgaris L. » Canadian Journal of Plant Science 83, n^o 3 (1 juillet 2003) : 629–44. http://dx.doi.org/10.4141/p01-124.

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Senecio vulgaris L. is a native of Eurasia, and has been introduced to and become naturalized in North America, South America, Africa and Australia. In Canada, it is found in all provinces and the Northwest and Yukon Territo ries. High fecundity, rapid wind dispersal, continuous germination under a wide range of growing conditions, rapid growth rate, ability to set seed a number of times per growing season and lack of chemical control options has made this species an importan t weed of some horticultural crops. This species produces pyrrolizidine alkaloids that have been implicated as a cause of liver toxicity in livestock. Populations of S. vulgaris have displayed resistance to Group 5, 6 and 7 herbicides (triazines, uracils, substituted ureas and nitriles) and other photosynthetic-transport-inhibiting herbicides. Triazine resistance in S. vulgaris was the first reported case of herbicide resistance worldwide. A rust pathogen, Puccinia lagenophorae Cooke, is currently being evaluated for control of S. vulgaris in Europe. Key words:

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MacLennan, Paul A., Elizabeth Delzell, Nalini Sathiakumar, Susan L. Myers, Hong Cheng, William Grizzle, Vivien W. Chen et Xiao Cheng Wu. « Cancer Incidence Among Triazine Herbicide Manufacturing Workers ». Journal of Occupational and Environmental Medicine 44, n^o 11 (novembre 2002) : 1048–58. http://dx.doi.org/10.1097/00043764-200211000-00011.

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Kodama, Tohru, Linxian Ding, Makiko Yoshida et Masao Yajima. « Biodegradation of an s-triazine herbicide, simazine ». Journal of Molecular Catalysis B : Enzymatic 11, n^o 4-6 (janvier 2001) : 1073–78. http://dx.doi.org/10.1016/s1381-1177(00)00169-7.

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Creuzet, Sophie, et Teresa Miranda. « Comparison of Experimental and Calculated Hydrogen Bonding Properties of Some Urea and Triazine Inhibitors of Photosystem II ». Zeitschrift für Naturforschung C 48, n^o 3-4 (1 avril 1993) : 179–84. http://dx.doi.org/10.1515/znc-1993-3-412.

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Abstract Previous studies of structure/activity relationships of photosystem II inhibitors, including comparisons of their inhibitory power in herbicide-resistant and susceptible chloroplasts, have led to predict the role of hydrogen bonding, associated to hydrophobicity, in the binding onto the QB site. The crystallographic structures of bacterial reaction centers now allow these bonds to be identified. In order to be able to understand the binding of various herbicides and the effects of resistance mutations within the QB site, a reliable estimation of hydrogen bonding strengths is needed. We show here, by calculating interactions with model compounds, controlled by physicochemical measurements, that the hydrogen bonding properties of the C = X nucleophilic moiety present in most PS II inhibitors are different for triazines as compared to urea or amide derivatives. Semiempirical methods (AM 1) fail to reproduce the energies of hydrogen bonds between a triazine ring nitrogen and a phenolic proton. An empirical method (SIBFA), designed to reproduce interaction energies, has been adapted with the aim of calculating the binding energies of various herbicides with models of the QB site.

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Oettmeier, Walter, et Silvana Preuße. « Herbicide and Quinone Binding to Chromatophores and Reaction Centers from Rhodobacter sphaeroides ». Zeitschrift für Naturforschung C 42, n^o 6 (1 juin 1987) : 690–92. http://dx.doi.org/10.1515/znc-1987-0607.

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Besides s-triazine and triazinone herbicides the chromone stigmatellin and tetrahalogen-substituted 1.4-benzoquinones are inhibitors of photosynthetic electron flow from reduced cytochrome c to ubiquinone-6 in isolated bacterial reaction centers. With isolated bacterial chromatophores binding experiments with radiolabeled herbicides can be performed in a similar way as with thylakoids from higher plants. Tetrahalogen-substituted 1.4-benzoquinones in a Michael type reaction can add onto nucleophilic groups in proteins. In bacterial reaction centers, a [14C]tetra- bromo-1.4-benzoquinone (bromanil) exclusively binds to the H-subunit.

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Sinclair, John, et Philip Macdonald. « Photosystem II activity and triazine resistance in weeds ». Canadian Journal of Botany 65, n^o 10 (1 octobre 1987) : 2147–51. http://dx.doi.org/10.1139/b87-296.

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The oxygen-evolving properties of broken chloroplasts isolated from biotypes of Chemopodium album and Amaranthus retroflexus that were either sensitive or resistant to s-triazine herbicides were compared. The pattern of oxygen flash yields produced by herbicide-sensitive, dark-adapted chloroplasts of either species was reminiscent of that found with spinach chloroplasts. In contrast, dark-adapted chloroplasts isolated from the herbicide-resistant biotypes exhibited a highly damped oxygen flash pattern in which there was significant oxygen released after the first light flash. Analysis of these results with the Kok model of photosystem II (Kok, B., Forbush, B., and McGloin, M. 1970. Photochem. Photobiol. 11: 457–475) suggested that the unusual properties of the resistant organelles were due to the survival of significant amounts of S3 and S2 states during dark adaptation and to a higher proportion of inactive photosystem II reaction centres during each light flash. Deactivation experiments verified the suggestion that the S3 and S2 states more readily survive a 10-min dark period in resistant organelles. Information about electron transport on the oxidizing side of photosystem II was obtained with a modulated oxygen electrode and suggested that there was no difference between the two biotypes in the value of the rate constant of the reaction that limits the rate of electron transport between the water-splitting step and photosystem II.

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Harvey, R. Gordon. « Herbicide Dissipation from Soils with Different Herbicide use Histories ». Weed Science 35, n^o 4 (juillet 1987) : 583–89. http://dx.doi.org/10.1017/s0043174500060598.

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Herbicide dissipation was monitored in soils differing in herbicide use histories. Repeated annual applications over 5 yr enhanced biodegradation of butylate [S-ethyl bis(2-methylpropyl)carbamothioate] and EPTC (S-ethyl dipropylcarbamothioate) but not alachlor {2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide}, atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine], cyanazine {2-[[(4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropanenitrile}, or metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide]. Prior application of butylate or EPTC enhanced biodegradation of the other thiocarbamate herbicide but not alachlor, atrazine, cyanazine, or metolachlor. Prior application of alachlor, atrazine, cyanazine, metolachlor, or trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine] did not enhance biodegradation of butylate or EPTC. Dissipation of EPTC applied with dietholate (O,O-diethyl-O-phenolphosphorothioate) was not enhanced by prior application of alachlor, atrazine, or trifluralin. Prior use of EPTC, EPTC + dietholate, butylate, or cycloate, respectively, enhanced biodegradation of EPTC in 100, 100, 71, and 50% of the experiments, of EPTC applied with dietholate in 57, 100, 60, and 33% of the experiments, of butylate in 33, 40, 100, and 20% of the experiments, and of cycloate in 0, 0, 17, and 0% of the experiments. Prior thiocarbamate herbicide applications usually did not enhance cycloate biodegradation, but soils from two locations without prior pesticide use histories rapidly degraded the herbicide. Storage of soil samples at 25 C for 6 or 12 months before application of EPTC and EPTC + dietholate resulted in less herbicide degradation than storage at 15 C. Differences in prior environmental conditions such as temperature may explain why development of enhanced biodegradation varied between years even in the same field plots.

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Storchous, I., et Yu Stefkivska. « Ammonium glufosinate and triazine herbicides have side effects on soil microorganisms and pathogens ». Karantin i zahist roslin, n^o 9-10 (17 novembre 2019) : 6–11. http://dx.doi.org/10.36495/2312-0614.2019.9-10.6-11.

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Goal. Analysis and synthesis of research results regarding the beneficial and negative side effects of ammonium glufosinate and thiazine herbicides on microorganisms. Methods. System-analytical, abstract-logical, empirical. Results. Information on the side effects of herbicides with the content of the active substance glufosinate ammonium and derivatives of thiazine herbicides is given. One of the side effects of herbicides that attracts attention is their biological activity. The biological activity of herbicides goes beyond the effects on target organisms and, thus, herbicides can influence the plant-pathogen interaction through their effect on the causative agent or on the surrounding soil microorganisms, including symbiotic relationships. As a side effect, both a decrease and an increase in diseases caused by phytopathogens that affect leaves, stems or roots are established. However, in some cases, the results obtained in in vitro experiments differed from the results obtained in field conditions in vivo or on a host plant. The phenomenon of the manifestation of side effects of herbicides was first discovered in the early 1940s and began to be studied in more detail since 1960. Conclusions. Generalized information about the history, studies of the side effects of herbicides on different cultures and in different conditions in the world. It is important that such effects are not fully studied, and these mechanisms attract the attention of scientists for their further research. Future studies are planned to be carried out using high-precision methods, such as chip-based technologies, to study all the mechanisms involved in the pathogen-plant interaction, which are modulated by herbicides. This trilateral relationship today is studied as a molecular and biochemical cross-linkage between a plant and a pathogen, a plant and a herbicide, as well as a pathogen and a herbicide. Active studies by foreign scientists of the side effects of herbicides show that in Ukraine, as an agrarian state, it is necessary to purposefully investigate the effect of herbicides on soil microorganisms and pathogens to optimize the use of plant protection products in agricultural production.

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Morash, R., et B. Freedman. « The effects of several herbicides on the germination of seeds in the forest floor ». Canadian Journal of Forest Research 19, n^o 3 (1 mars 1989) : 347–50. http://dx.doi.org/10.1139/x89-052.

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In a laboratory experiment, we studied the effects of perturbation of a forest floor substrate with six concentrations (10, 50, 100, 500, 1000, and 5000 ppm) of four herbicides: glyphosate (N-phosphonomethyl glycine), 2,4,5-T (2,4,5-trichlorophenoxy acetic acid), triclopyr (3,5,6-trichloro-pyridinyloxyacetic acid), and two formulations of hexazinone (3-cyclohexyl-6-(dimethylamino)-1-methyl-1-1,3,5-triazine-2,4(1H,3H)dione). Although their toxic thresholds differ, the herbicides all caused significant decreases in the germination of seeds. However, large decreases in germination only occurred at concentrations that are unrealistically large in comparison with the herbicide residues that actually occur after a silvicultural treatment. In a parallel field experiment, no significant difference in seedling germination was observed for forest floor samples that were exposed to or shielded from herbicide deposition at two sites that were sprayed in an operational program.

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Liu, Xianxian, et Rebecca E. Parales. « Bacterial Chemotaxis to Atrazine and Related s-Triazines ». Applied and Environmental Microbiology 75, n^o 17 (6 juillet 2009) : 5481–88. http://dx.doi.org/10.1128/aem.01030-09.

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ABSTRACT Pseudomonas sp. strain ADP utilizes the human-made s-triazine herbicide atrazine as the sole nitrogen source. The results reported here demonstrate that atrazine and the atrazine degradation intermediates N-isopropylammelide and cyanuric acid are chemoattractants for strain ADP. In addition, the nonmetabolized s-triazine ametryn was also an attractant. The chemotactic response to these s-triazines was not specifically induced during growth with atrazine, and atrazine metabolism was not required for the chemotactic response. A cured variant of strain ADP (ADP M13-2) was attracted to s-triazines, indicating that the atrazine catabolic plasmid pADP-1 is not necessary for the chemotactic response and that atrazine degradation and chemotaxis are not genetically linked. These results indicate that atrazine and related s-triazines are detected by one or more chromosomally encoded chemoreceptors in Pseudomonas sp. strain ADP. We demonstrated that Escherichia coli is attracted to the s-triazine compounds N-isopropylammelide and cyanuric acid, and an E. coli mutant lacking Tap (the pyrimidine chemoreceptor) was unable to respond to s-triazines. These data indicate that pyrimidines and triazines are detected by the same chemoreceptor (Tap) in E. coli. We showed that Pseudomonas sp. strain ADP is attracted to pyrimidines, which are the naturally occurring structures closest to triazines, and propose that chemotaxis toward s-triazines may be due to fortuitous recognition by a pyrimidine chemoreceptor in Pseudomonas sp. strain ADP. In competition assays, the presence of atrazine inhibited chemotaxis of Pseudomonas sp. strain ADP to cytosine, and cytosine inhibited chemotaxis to atrazine, suggesting that pyrimidines and s-triazines are detected by the same chemoreceptor.

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Holt, Jodie S., et Homer M. Lebaron. « Significance and Distribution of Herbicide Resistance ». Weed Technology 4, n^o 1 (mars 1990) : 141–49. http://dx.doi.org/10.1017/s0890037x00025148.

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Herbicide-resistant weed species have become widespread in recent years. Fifty-five weed species, including 40 dicots and 15 grasses, are known to have biotypes resistant to the triazine herbicides. One or more resistant species have arisen in 31 states of the United States, four provinces of Canada, 18 countries in Europe, and Israel, Japan, Australia, and New Zealand. Resistance to other classes of herbicides is more restricted in distribution and recent in detection but is becoming more widespread. Trifluralin resistance has spread in the southeastern United States and has been detected in Canada, while 11 species with biotypes resistant to paraquat have been reported around the world. Diclofop-methyl-resistant weed species are problems in cereal production in Australia and have been found in Oregon, South Africa, and the United Kingdom. Resistance to the substituted ureas also is present in the United Kingdom, West Germany, and Hungary. Within the last 2 yr, biotypes of at least four weed species resistant to the sulfonylurea herbicides have arisen following several annual applications of these herbicides in wheat. Some resistant biotypes have multiple resistance to different classes of herbicides, which greatly exacerbates the threat of resistance. Herbicide resistance has reached the level where more concerted efforts are needed in research, education, and development of effective management strategies to preserve herbicides as essential tools of agricultural technology.

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Walsh, Michael J., Karrie Stratford, Kent Stone et Stephen B. Powles. « Synergistic Effects of Atrazine and Mesotrione on Susceptible and Resistant Wild Radish (Raphanus raphanistrum) Populations and the Potential for Overcoming Resistance to Triazine Herbicides ». Weed Technology 26, n^o 2 (juin 2012) : 341–47. http://dx.doi.org/10.1614/wt-d-11-00132.1.

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The synergistic interaction between mesotrione, a hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide, and atrazine, a photosystem II (PS II)-inhibiting herbicide, has been identified in the control of several weed species. A series of dose–response studies examined the synergistic effect of these herbicides on a susceptible (S) wild radish population. The potential for this interaction to overcome target-sitepsbA gene-based atrazine resistance in a resistant (R) wild radish population was also investigated. Control of S wild radish with atrazine was enhanced by up to 40% when low rates (1.0 to 1.5 g ha−1) of mesotrione were applied in combination. This synergistic response was demonstrated across a range of atrazine–mesotrione rate combinations on this S wild radish population. Further, the efficacy of 1.5 g ha−1mesotrione increased control of the R population by a further 60% when applied in combination with 400 g ha−1of atrazine. This result clearly demonstrated the synergistic interaction of these herbicides in overcoming the target-site resistance mechanism. The mechanism responsible for the observed synergistic interaction between mesotrione and atrazine remains unknown. However, it is speculated that an alternate atrazine binding site may be responsible. Regardless of the biochemical nature of this interaction, evidence from whole-plant bioassays clearly demonstrated that synergistic herbicide combinations improve herbicide efficiency, with lower application rates required to control weed populations. This, combined with the potential to overcomepsbA gene-based triazine resistance, and, thereby, regain the use of these herbicides, will result in more sustainable herbicide use.

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Krutz, L. Jason, Ian C. Burke, Krishna N. Reddy, Robert M. Zablotowicz et Andrew J. Price. « Enhanced Atrazine Degradation : Evidence for Reduced Residual Weed Control and a Method for Identifying Adapted Soils and Predicting Herbicide Persistence ». Weed Science 57, n^o 4 (août 2009) : 427–34. http://dx.doi.org/10.1614/ws-09-010.1.

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Soilborne bacteria with novel metabolic abilities have been linked with enhanced atrazine degradation and complaints of reduced residual weed control in soils with ans-triazine use history. However, no field study has verified that enhanced degradation reduces atrazine's residual weed control. The objectives of this study were to (1) compare atrazine persistence and prickly sida density ins-triazine-adapted and nonadapted field sites at two planting dates; (2) utilize original and published data to construct a diagnostic test for identifyings-triazine-adapted soils; and (3) develop and validate ans-triazine persistence model based on data generated from the diagnostic test, i.e., mineralization of ring-labeled14C-s-triazine. Atrazine half-life values ins-triazine-adapted soil were at least 1.4-fold lower than nonadapted soil and 5-fold lower than historic estimates (60 d). At both planting dates atrazine reduced prickly sida density in the nonadapted soils (P ≤ 0.0091). Conversely, in thes-triazine-adapted soil, prickly sida density was not different between no atrazine PRE and atrazine PRE at the March 15 planting date (P = 0.1397). A lack of significance in this contrast signifies that enhanced degradation can reduce atrazine's residual control of sensitive weed species. Analyses of published data indicate that cumulative mineralization in excess of 50% of C0after 30 d of incubation is diagnostic for enhanceds-triazine degradation. Ans-triazine persistence model was developed and validated; model predictions for atrazine persistence under field conditions were within the 95% confidence intervals of observed values. Results indicate that enhanced atrazine degradation can decrease the herbicide's persistence and residual activity; however, coupling the diagnostic test with the persistence model could enable weed scientists to identifys-triazine-adapted soils, predict herbicide persistence under field conditions, and implement alternative weed control strategies in affected areas if warranted.

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Ronka, Sylwia, Małgorzata Kujawska et Honorata Juśkiewicz. « Triazines removal by selective polymeric adsorbent ». Pure and Applied Chemistry 86, n^o 11 (1 novembre 2014) : 1755–69. http://dx.doi.org/10.1515/pac-2014-0722.

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Abstract The objective of the study was to investigate sorption of simazine, atrazine, propazine and terbuthylazine on specific polymeric adsorbent and thereby evaluate the possibility of triazine-based herbicide removal from the aqueous solution. In order to obtain polymer adsorbent for triazines removal, the poly(divinylbenzene) was synthesized in radical polymerization using bead polymerization, and modified with maleic anhydride in Diels–Alder reaction with subsequent base hydrolysis. The porous material containing carboxyl groups was obtained. Experiments have been performed in single and multi-component mixtures of herbicide in the ppm concentration range. Introduction of carboxyl groups into polymer structure resulted in obtaining specific interactions, such as hydrogen bonds between modified poly(divinylbenzene) and triazines, therefore intensification of adsorption was observed. Calculated distribution coefficients of triazines (K = 2600–35 100) testify to their effective removal from aqueous solutions on the studied adsorbent. Selective sorption of triazines is observed and explained in relation to the binding mechanism which involve hydrophobic interactions and hydrogen bonding. The effect of the adsorbate structure on the ability to form specific interactions with the tested adsorbent was investigated. The kinetic of sorption and the parameters of Langmuir and Freundlich isotherms for the studied systems were determined.

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