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Herbicide substances aminopyralid and pyroxsulam are used to control broadleaf weeds in cereals. Disadvantage of this herbicides is fact, that their residues remain not only in the soil, but are also translocated to the plant tissues of the treated crops. Herbicide residues released from straw used like mulch by the way of decomposition and leaching can damage strawberry. In this study the response of strawberry plants to aminopyralid at doses of 3.75, 7.5 and 15 g/ha and pyroxsulam at dose 3, 15 and 30 g/ha was evaluated. With the increased concentration of both herbicides, plants injury also increased. A reduction in fruit yield was noted with both herbicides and cultivar 'Elsanta' was more sensitive than cultivar 'Karmen'. Mustang Forte herbicide at the highest rate reduced the yield of the 'Elsanta' cultivar by 52% and the 'Karmen' cultivar by 47% in the first year. However, in the second year, the decrease in yields of both varieties leveled off at 30% compared to the control. Similarly, in the case of pyroxsulam, the yield of cultivar 'Elsanta' decreased by 70% in the first year, while yield of cultivar 'Karmen' only decreased by 55%, but here the difference between cultivars remained until the second year. [ABSTRACT FROM AUTHOR]

Herbicides can pose a serious hazard to aquatic organisms and human health. Herbicides prepared as a mixture formulation may have much more toxic effects, but there are few studies in the literature showing the toxicities of these herbicides. In our study, the toxic effects of different concentrations (0.25, 0.5 and 1 ppm) of mixed herbicides (Halauxifen methyl+Pyroxsulam+Cloquintocet acid), which have been used extensively in the market in recent years, on zebrafish embryos and larvae were evaluated with developmental parameters and behavioral tests. Embryos and larvae exposed to the mixed herbicides for 96 hours had reduced survival and delayed exit from the chorion, especially at the highest application concentration (1 ppm). Various malformations were observed in embryos and larvae with the effect of mixed herbicides. In addition, it was determined that the total distance covered by zebrafish larvae at 96th hour increased and hyperactivity occurred at 1 ppm concentration of the mixed herbicide. Our study provides important data in terms of understanding the toxic effects of mixed chemicals on aquatic organisms. As a result, more and more detailed studies are required since chemicals (herbicides, insecticides, fungicides or heavy metals) found as a mixture in the aquatic ecosystem are considered to be a threat to aquatic organisms. [ABSTRACT FROM AUTHOR]

Italian ryegrass (Lolium multiflorum L.), a cross-pollinated grass, is gradually becoming a predominant weed in wheat fields in China and is evolving resistance to many groups of herbicides. The aim of this study is to determine the resistance levels of a single L. multiflorum population from a wheat field in Henan Province China, to three modes of action (MoAs) of herbicides and to further characterize the potential resistance mechanisms. This L. multiflorum population evolved multiple herbicide resistances to pyroxsulam [acetolactate synthase (ALS)], pinoxaden [acetyl-CoA carboxylase (ACCase)] and isoproturon [photosystem II (PSII)]. Target-site resistance (TSR) mutations (Pro-197-Gln, Pro-197-Thr, and Trp-574-Leu) and non-target-site resistance (NTSR) mediated by cytochrome P450 monooxygenase (CYP450) genes were associated with pyroxsulam resistance. Pinoxaden resistance was conferred by two TSR mutations, which referred to a rare Ile-2041-Val mutation and a common Ile-1781-Leu mutation but with two different nucleotide substitutions (CTA/TTA). CYP450- and glutathione-S-transferase (GST)-mediated resistances were the main resistance mechanisms for this multiple herbicide-resistant (MHR) population to the PSII inhibitor isoproturon. This is the first case of a single L. multiflorum population evolving multiple resistance to three herbicide MoAs (ALS, ACCase and PSII) in China. Diverse resistance mechanisms including TSR and NTSR mean L. multiflorum exhibits a high degree of resistance plasticity. [ABSTRACT FROM AUTHOR]

Die Bekämpfung von Ackerfuchsschwanz (Alopecurus myosuroides Huds.) stellt vor dem Hintergrund der zunehmenden Resistenzen eine Herausforderung dar. Strategien zur Resistenzvermeidung beinhalten das Alternieren der Wirkstoffe oder ihre Anwendung in Mischungen bzw. in Sequenz. Unabhängig der gewählten Strategie stellt sich immer die Frage welche Resistenzmechanismen durch welche Anwendung positiv, gar nicht oder negativ selektiert werden. Der Blick in dieser Arbeit wird auf die metabolische Resistenz (NTSR) gelegt. Ihre Evolution erfolgt in kleinen quantifizierbaren Schritten und die Ausprägung von Kreuzresistenzen gegen weitere Wirkstoffe bleibt schwer vorhersagbar. Mit den im Getreide zur Bekämpfung von Ackerfuchsschwanz (Alopecurus myosuroides Huds.) eingesetzten Wirkstoffen Pinoxaden (HRAC 1) und Pyroxsulam (HRAC 2) wurde die Evolution von Resistenz bzw. Kreuzresistenz in Gewächshausversuchen für die 1. Generation experimentell simuliert. Dazu wurde eine Anzucht aus der ursprünglichen Feld-Population in drei Teilpopulationen unterteilt. Diese Teilpopulationen wurden mit jeweils 10 % der Feldaufwandmenge der Einzelwirkstoffe Pinoxaden und Pyroxsulam oder der Mischung dieser Wirkstoffe behandelt. Die Überlebenden dieser Behandlung wurden dann getrennt als Teilpopulation weiter vermehrt (F1). Die Empfindlichkeit der drei F1-Populationen und der Elterngeneration (P) gegenüber Pinoxaden, Pyroxsulam und der Mischung wurde in insgesamt 12 Dosis-Wirkungsversuchen verglichen. Die mit Pinoxaden selektierte F1-Population zeigte als einzige Teilpopulation eine signifikante Verschiebung der Unempfindlichkeit gegen Pinoxaden im Vergleich zu der P-Generation mit einem Faktor von 6. Nach Selektion in nur einer Generation konnte eine spezifisch gegen Pinoxaden metabolische Resistenz selektiert werden, die sich mit der Feldaufwandmenge nicht mehr ausreichend bekämpfen ließ.

Highland barley is one of the few crops that can be grown at high elevations, making it a key resource within the Tibet Plateau. Weeds are a significant threat to highland barley production, and new herbicides and tolerant barley varieties are needed to control this ever-growing problem. A better understanding of existing herbicide resistance mechanisms is therefore needed. In this study, transcriptomic and metabolomic analyses were used to identify molecular and physiological changes in two highland barley genotypes with differing sensitivities to the herbicide pyroxsulam. We identified several stressresponsive metabolites, including flavonoids and antioxidants, which accumulated to significantly higher levels in the pyroxsulam-resistant genotype. Additionally, we found key genes in both the flavonoid biosynthesis pathway and the antioxidant system that were up-regulated in pyroxsulam-resistant barley. This work significantly expands on the current understanding of the molecular mechanisms underlying differing pyroxsulam tolerance among barley genotypes and provides several new avenues to explore for breeding or engineering tolerant barley. [ABSTRACT FROM AUTHOR]

The persistence and dissipation of a new readymix formulation of halauxifen-methyl + pyroxsulam was investigated in three soils viz. red lateritic (Soil A), coastal saline (Soil B) and black soil (Soil C) under three incubation temperatures (20, 30 and 40° C). Soil samples were fortified at 1.0 (T1) and 2.0 (T2) mg kg− 1 doses separately for both compounds. The analytical methods showed satisfactory mean recovery, precision and linearity and therefore accepted for analysis. Both molecules followed single first-order kinetics. A significant influence of soil type on the persistence of both herbicides was observed. The order of stability of halauxifen-methyl was Soil A > B > C and for pyroxsulam was Soil B > C > A. Besides, a faster rate of dissipation of halauxifen-methyl and pyroxsulam was recorded at elevated temperatures, regardless of soil type. This research will help to understand the effect of temperature on the fate of the herbicide mixture in soils of diverse agro-climatic regions. [ABSTRACT FROM AUTHOR]

Black grass (Alopecurus myosuroides Huds.) is a highly competitive weed in winter wheat fields of China. Due to repeated use of acetolactate synthase (ALS) inhibitors, many A. myosuroides populations have evolved resistance to pyroxsulam in some wheat fields. Research was conducted to determine the molecular basis of herbicide resistance in the AH93 A. myosuroides population. Whole-plant dose–response assay confirmed that the AH93 population was resistant to pyroxsulam with a resistance index of 4.2. Cross- and multiple-resistance assays indicated that the AH93 population was cross-resistant to mesosulfuron-methyl and multiple-resistant to pinoxaden. Sequencing of the ALS and ACCase gene revealed that there was no target-site mutation in ALS, but Trp-2027-Cys and Cys-2088-Arg amino acid mutations in ACCase in the AH93 population. A malathion pretreatment study indicated that the AH93 population might have cytochrome P450–mediated herbicide metabolic resistance. This is the first report of pyroxsulam resistance in a multiple-resistant A. myosuroides population in China, and the Cys-2088-Arg mutation is the first reported case of an ACCase mutant conferring herbicide resistance in A. myosuroides. [ABSTRACT FROM AUTHOR]

Multiple herbicide resistance in diverse weed species endowed by enhanced herbicide detoxification or degradation is rapidly growing into a great threat to herbicide sustainability and global food safety. Although metabolic resistance is frequently documented in the economically damaging arable weed species shortawn foxtail (Alopecurus aequalis Sobol.), relevant molecular knowledge has been lacking. Previously, we identified a field population of A. aequalis (R) that had evolved metabolic resistance to the commonly used acetolactate synthase (ALS)-inhibiting herbicide mesosulfuron-methyl. RNA sequencing was used to discover potential herbicide metabolism-related genes, and four cytochrome P450s (CYP709C56, CYP71R18, CYP94C117, and CYP94E14) were identified with higher expressions in the R vs. susceptible (S) plants. Here the full-length P450 complementary DNA transcripts were each cloned with identical sequences between the S and R plants. Transgenic Arabidopsis overexpressing CYP709C56 became resistant to the sulfonylurea herbicide mesosulfuron-methyl and the triazolo-pyrimidine herbicide pyroxsulam. This resistance profile generally but does not completely in accordance with what is evident in the R A. aequalis. Transgenic lines exhibited enhanced capacity for detoxifying mesosulfuron-methyl into O-demethylated metabolite, which is in line with the detection of O-demethylated herbicide metabolite in vitro in transformed yeast. Structural modeling predicted that mesosulfuron-methyl binds to CYP709C56 involving amino acid residues Thr-328, Thr-500, Asn-129, Gln-392, Phe-238, and Phe-242 for achieving O-demethylation. Constitutive expression of CYP709C56 was highly correlated with the metabolic mesosulfuron-methyl resistance in A. aequalis. These results indicate that CYP709C56 degrades mesosulfuron-methyl and its up-regulated expression in A. aequalis confers resistance to mesosulfuron-methyl. [ABSTRACT FROM AUTHOR]

Copyright of Julius-Kühn-Archiv is the property of Julius Kuehn Institut and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Italian ryegrass (Lolium multiflorum L.), a cross-pollinated grass, is gradually becoming a predominant weed in wheat fields in China and is evolving resistance to many groups of herbicides. The aim of this study is to determine the resistance levels of a single L. multiflorum population from a wheat field in Henan Province China, to three modes of action (MoAs) of herbicides and to further characterize the potential resistance mechanisms. This L. multiflorum population evolved multiple herbicide resistances to pyroxsulam [acetolactate synthase (ALS)], pinoxaden [acetyl-CoA carboxylase (ACCase)] and isoproturon [photosystem II (PSII)]. Target-site resistance (TSR) mutations (Pro-197-Gln, Pro-197-Thr, and Trp-574-Leu) and non-target-site resistance (NTSR) mediated by cytochrome P450 monooxygenase (CYP450) genes were associated with pyroxsulam resistance. Pinoxaden resistance was conferred by two TSR mutations, which referred to a rare Ile-2041-Val mutation and a common Ile-1781-Leu mutation but with two different nucleotide substitutions (CTA/TTA). CYP450- and glutathione-S-transferase (GST)-mediated resistances were the main resistance mechanisms for this multiple herbicide-resistant (MHR) population to the PSII inhibitor isoproturon. This is the first case of a single L. multiflorum population evolving multiple resistance to three herbicide MoAs (ALS, ACCase and PSII) in China. Diverse resistance mechanisms including TSR and NTSR mean L. multiflorum exhibits a high degree of resistance plasticity.

Herbicides are the most effective tool against weed flora in cereal crops that help to maintain and increase crop yields. This investigation was conducted in the winter season of 2018 to study the stress effect of three post-emergence herbicides including pinoxaden, tribenuron-methyl, and pyroxsulam on the biochemical changes at the molecular cell level of wheat. These herbicides were applied either lonely with a rate of 0.45 L.ha−1, 22.5 gm.ha−1, and 0.16 Ib a.i/A, respectively, or in combinations together on three Egyptian varieties of bread wheat known as Misr 1, Giza17 1, and Gemmiza 11. Firstly, the abovementioned herbicides were used at the recommended and half recommended doses with their combinations for these varieties to investigate DNA-protein linkage as a signal effect of herbicides at the molecular cell level. Our data showed that the treatment of wheat varieties with the tested herbicides induced new bands with low and high molecular weights of 37.49, 40.08, 146.55, and 147.23 KDa with relative mobility of 0.1574, 0.1603, 0.2166, and 0.2168, respectively. These bands were not presented in the control treatment, suggesting that it might be used as a biochemical marker for plant defense genes. Meanwhile, the control treatment exhibited only five or six bands in the three varieties. However, the tested varieties showed that the same number of bands, the molecular weights of bands, and their relative mobility were significantly varied between the single and the combinations treatment of herbicides. The best treatment was achieved by the combination between pinoxaden and tribenuron-methyl at a recommended dose which induced a large number of protein bands compared to the control treatment on the wheat variety cv. Misr 1, which gave one band with low molecular weight 71.44 KDa at Rf 0.1854 and other with the highest molecular weight 147.23 KDa at Rf 0.2168, compared to the control treatment. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Black grass (Alopecurus myosuroides Huds.) is a highly competitive weed in winter wheat fields of China. Due to repeated use of acetolactate synthase (ALS) inhibitors, many A. myosuroides populations have evolved resistance to pyroxsulam in some wheat fields. Research was conducted to determine the molecular basis of herbicide resistance in the AH93 A. myosuroides population. Whole-plant dose–response assay confirmed that the AH93 population was resistant to pyroxsulam with a resistance index of 4.2. Cross- and multiple-resistance assays indicated that the AH93 population was cross-resistant to mesosulfuron-methyl and multiple-resistant to pinoxaden. Sequencing of the ALS and ACCase gene revealed that there was no target-site mutation in ALS, but Trp-2027-Cys and Cys-2088-Arg amino acid mutations in ACCase in the AH93 population. A malathion pretreatment study indicated that the AH93 population might have cytochrome P450–mediated herbicide metabolic resistance. This is the first report of pyroxsulam resistance in a multiple-resistant A. myosuroides population in China, and the Cys-2088-Arg mutation is the first reported case of an ACCase mutant conferring herbicide resistance in A. myosuroides.

Background: Since 2008, Pyroxsulam was registered by Dow Agro Sciences as efficient broad- spectrum herbicide for wheat control. Wheat is an important plant involved in the daily meal of human and it is a rich source for benefit contents. Aim: The present project aimed to study the effect of Pyroxsulam herbicide on the levels of some parameters in Iraqi wheat. Materials and Methods: We investigated the concentration of three metals (Ni, Cd, and Pb) and flavonoid in seeds of wheat plants collected from two Iraqi cultivates (Iba 99 and Abu Ghraib 3). Halve of the planted wheat was sprayed with Pyroxsulam herbicide (S group) while the other group was considered as a control group (C group). Results: The results showed that the levels of Ni (an essential cofactor of eight enzymes) and the antioxidant parameter (total flavonoids) were negatively affected as a result of treatment with Pyroxsulam. This effect was clearly apparent from the significant drop in most data of these elements, the same result was indicated for the (Cd, and Pb) concentrations which they passed to the soil. By comparison, Iba 99 cultivate is more crop with using the herbicide than Abu Ghraib 3 cultivate. Conclusion: According to the above results, wheat products after treatment with Pyroxsulam would have less in some antioxidant related contents and it would be useful to design an alternative dose or solution of this herbicide to get healthy products of wheat with high yield. [ABSTRACT FROM AUTHOR]

A QuEChERS method with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was modified and validated for the determination of florasulam and pyroxsulam residues in wheat grain and straw. The validated method was applied to cereals including oat, millet, corn and rice. Average recoveries were 76-113% with RSDs 2-15%. The limits of quantitation (LOQ) were 0.005 mg/kg for wheat grain and 0.01 mg/kg for wheat straw and four cereals. Ion suppression for florasulam (−28% to −76%) was observed in all the matrices except corn, whereas ion enhancement were shown for pyroxsulam (44% to 83%). Degradation rates of florasulam and pyroxsulam were 6% and 23%, respectively, in wheat grain and straw after eight-week storage at −20°C. The ultimate residues in field trials in ten regions were all ≤0.05 mg/kg, and long term dietary risk assessment indicated that hazard quotients were 0.02% and 0.001% for florasulam and pyroxsulam, respectively, which shows that it is safe to spray the two herbicides on wheat. [ABSTRACT FROM AUTHOR]

[Ｏｂｊｅｃｔｉｖｅｓ]Ｔｈｅ ｐｕｒｐｏｓｅ ｏｆ ｔｈｉｓ ｒｅｓｅａｒｃｈ ｉｓ ｔｏ ｓｃｒｅｅｎ ｔｈｅ ｏｐｔｉｍａｌ ｐｒｏｐｏｒｔｉｏｎ ｏｆ ｔｈｅ ｍｉｘｔｕｒｅ ｏｆ ｐｙｒｏｓｕｌａｍ, ｐｉｎｏｘａｄｅｎ, ｉｓｏｐｒｏ- ｔｕｒｏｎ ａｎｄ ｖｅｒｉｆｙ ｉｔｓ ｆｉｅｌｄ ｅｆｆｉｃｉｅｎｃｙ ａｇａｉｎｓｔ ａｎｎｕａｌ ｗｅｅｄｓ ｉｎ ｗｈｅａｔ ｆｉｅｌｄｓ, ａｓ ｗｅｌｌ ａｓ ｉｔｓ ｓａｆｅｔｙ ｔｏ ｗｈｅａｔ. [Ｍｅｔｈｏｄｓ]Ｔｈｅ ｓｙｎｅｒｇｉｓｍ ｏｆ ｔｈｅ ｍｉｘｔｕｒｅ ｗａｓ ｅｖａｌｕａｔｅｄ ｂｙ Ｃｏｌｂｙ’ｓ ｍｅｔｈｏｄ ａｎｄ ｔｈｅ ｏｐｔｉｍａｌ ｐｒｏｐｏｒｔｉｏｎ ｆｏｒ ｔｈｅ ｈｅｒｂｉｃｉｄｅ ｍｉｘｔｕｒｅ ｗａｓ ｏｂｔａｉｎｅｄ. Ｔｈｅ ｈｅｒｂｉｃｉｄａｌ ｓｐｅｃｔｒｕｍ ｔｏ ｗｅｅｄｓ ａｎｄ ｓａｆｅｔｙ ｔｏ ｗｈｅａｔ ｏｆ ｔｈｉｓ ｐｒｏｐｏｒｔｉｏｎ ｗｅｒｅ ｄｅｔｅｒｍｉｎｅｄ ｉｎ ｇｒｅｅｎｈｏｕｓｅ ｂｙ ｗｈｏｌｅ ｐｌａｎｔ ｂｉｏａｓｓａｙ. Ａｌｓｏ, ａ ｆｉｅｌｄ ｔｒｉａｌ ｗａｓ ｐｅｒｆｏｒｍｅｄ ｔｏ ｃｏｎｆｉｒｍ ｔｈｅ ｃｏｎｔｒｏｌｌｉｎｇ ｅｆｆｉｃｉｅｎｃｙ ｏｎ ａｎｎｕａｌ ｗｅｅｄｓ ａｎｄ ｓａｆｅｔｙ ｔｏ ｗｈｅａｔ. [Ｒｅｓｕｌｔｓ] Ｔｈｅ ｏｐｔｉｍａｌ ｐｒｏｐｏｒｔｉｏｎ ｆｏｒ ｔｈｅ ｍｉｘｔｕｒｅ ｏｆ ｔｈｅｓｅ ｔｈｒｅｅ ｈｅｒｂｉｃｉｄｅｓ ｗａｓ １∶５∶１００[ｍ(ｐｙｒｏｘｓｕｌａｍ) ∶ｍ(ｐｉｎｏｘａｄｅｎ) ∶ｍ(ｉｓｏｐｒｏｔｕｒｏｎ)]. Ａｔ ｔｈｅ ｄｏｓｅ ｏｆ ４００ ｇ􀅰ｈｍ－２, ｔｈｉｓ ｍｉｘｔｕｒｅ ｃｏｕｌｄ ｓｔｒｏｎｇｌｙ ｉｎｈｉｂｉｔ ｔｈｅ ｇｒｏｗｔｈ ｏｆ Ａｌｏｐｅｃｕｒｕｓ ｊａｐｏｎｉｃｕｓ, Ｂｅｃｋｍａｎｎｉａ ｓｙｚｉｇａｃｈｎｅ, Ｓｔｅｌｌａｒｉａ ｍｅｄｉａ, Ｖｉｃｉａ ｇｉｇａｎｔｅａ ａｎｄ Ｇａｌｉｕｍ ａｐａｒｉｎｅ, ｗｉｔｈ ｔｈｅ ｐｅｒｃｅｎｔａｇｅ ｉｎｈｉｂｉｔｉｏｎ ｏｎ ｆｒｅｓｈ ｗｅｉｇｈｔ ｏｆ １００.００％, ９９.７４％, １００.００％, ９０.５７％ ａｎｄ ９５.４９％, ｒｅｓｐｅｃｔｉｖｅｌｙ. Ａｌｓｏ ｔｈｅ ｍｉｘｔｕｒｅ ｗａｓ ｓａｆｅ ｔｏ ｗｈｅａｔ ｗｉｔｈ Ｚ ｖａｌｕｅ ｏｆ ６.４３. Ｂｙ ｆｉｅｌｄ ｔｒｉａｌ, ｉｔ ｗａｓ ｆｏｕｎｄ ｔｈａｔ ａｔ ４０ ｄａｙｓ ａｆｔｅｒ ｓｐｒａｙｉｎｇ, ｕｎｄｅｒ ｔｈｅ ｄｏｓｅ ｏｆ ６００ ｇ􀅰ｈｍ－２, ｔｈｅ ｃｏｎｔｒｏｌｌｉｎｇ ｅｆｆｉｃｉｅｎｃｙ ｏｆ ｔｈｅ ｍｉｘｔｕｒｅ ａｇａｉｎｓｔ ｔｈｅ ａｎｎｕａｌ ｗｅｅｄｓ ｉｎ ｗｈｅａｔ ｆｉｅｌｄｓ ｗａｓ ｈｉｇｈｅｒ ｔｈａｎ ９０％, ａｎｄ ｃａｕｓｅｄ ｎｏ ｖｉｓｉｂｌｅ ｄａｍａｇｅ ｔｏ ｗｈｅａｔ. [Ｃｏｎｃｌｕｓｉｏｎｓ]Ｔｈｅ ｍｉｘｔｕｒｅ ｏｆ ｐｙｒｏｘｓｕｌａｍ, ｐｉｎｏｘａｄｅｎ, ｉｓｏｐｒｏｔｕｒｏｎ ｗｉｔｈ ｔｈｅ ｏｐｔｉｍａｌ ｐｒｏｐｏｒｔｉｏｎ ｃｏｕｌｄ ｅｆｆｅｃｔｉｖｅｌｙ ｃｏｎｔｒｏｌ ｔｈｅ ａｎｎｕａｌ ｗｅｅｄｓ ｉｎ ｗｈｅａｔ ｆｉｅｌｄｓ ａｎｄ ｂｅ ｓａｆｅ ｔｏ ｗｈｅａｔ. [ABSTRACT FROM AUTHOR]

Copyright of Julius-Kühn-Archiv is the property of Julius Kuehn Institut and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Julius-Kühn-Archiv is the property of Julius Kuehn Institut and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The efficacy of different ALS-inhibiting herbicides for the control of brome species (Bromus spp.) was tested in three field trials in the year 2010 – 2012 in the region of North-West-Bavaria Franken. As a result of the trials the standard herbicide Attribut (Propoxycarbazone) was confirmed for the control of brome. In case of infestation with brome and black grass the herbicide Broadway (Pyroxsulam) offers a certain control of both problematic grass weeds. This illustrates the high dependency of sufficient brome control in winter cereals on the effectiveness of specific ALS-Inhibitor herbicides. Because of the high risk of herbicide resistance to ACCaseand ALS-inhibiting herbicides in brome, integrated weed management is essential for the sustainable control of brome in winter cereals, respectively winter wheat.

A black-grass (Alopecurus myosuroides Huds.) resistance-monitoring conducted by BASF in 2010 - 2012 revealed a high number of accessions with resistance against imazamox. However, application of imazamoxbased products in a winter crop was limited to winter beans in France and United Kingdom only until the introduction of the Clearfield®-production system in autumn 2012 in winter oilseed rape. It is therefore assumed that the resistance mechanisms were probably selected by the frequent use of ACCase- and ALSinhibitors in winter crop rotations during the last 2 decades. Resistance level for each product-biotype combination was calculated according the “R”-classification system (S, R?, RR, RRR) by directly comparing the product performance on a biotype versus untreated control. Majority of resistant biotypes did not show a target-site mutation at the known codon Pro197 or Trp574. In order to better evaluate the impact of Non-Target-Site-Resistance (NTSR) on the activity of BEYOND (imazamox), ATLANTIS WG (mesosulfuron+iodosulfuron) and ABAK (pyroxsulam), biotypes who have shown an ALS-target-site mutation were removed from further analysis. At the dose rate of 35 g ai/ha BEYOND provided good activity on susceptible biotypes of black-grass almost matching up with ATLANTIS WG and ABAK. However, activity of BEYOND declined stronger on biotypes classified as R? or RR for that product, while ATLANTIS WG and ABAK hardly showed any decline in control on this group of biotypes when applied at the recommended dose rate. It is assumed that the underlying NTSR-mechanism is not effective enough yet to confer resistance to ATLANTIS WG and ABAK, but on BEYOND. In contrast, biotypes classified as R? for ATLANTIS WG did show a stronger impact on the activity of BEYOND and ABAK then of ATLANTIS WG. These differences in control level probably do translate into differences in selection pressure as well.

BACKGROUND Bromus tectorum L. is one of the most troublesome grass weed species in cropland and non-cropland areas of the northwestern USA. In summer 2016, a B. tectroum accession (R) that survived imazamox at the field-use rate (44 g ha-1) in an imidazolinone-tolerant (IMI-tolerant or Clearfield™) winter wheat field was collected from a wheat field in Carter County, MT, USA. The aim of this study was to determine the resistance profile of the B. tectroum R accession to imazamox and other ALS inhibitors, and investigate the mechanism of resistance to imazamox. RESULTS The R B. tectorum accession had a high-level resistance (110.1-fold) to imazamox (IMI) and low to moderate-levels cross-resistance to pyroxsulam (TP) (4.6-fold) and propoxycarbazone (SCT) (13.9-fold). The R accession was susceptible to sulfosulfuron (SU) and quizalofop and clethodim (ACCase inhibitors), paraquat (PS I inhibitor), glyphosate (EPSPS inhibitor) and glufosinate (GS inhibitor). Sequence analysis of the ALS gene revealed a single, target-site Ser653Asn mutation in R plants. Pretreatment of malathion followed by imazamox at 44 or 88 g ha-1 did not reverse the resistance phenotype. CONCLUSION This is the first report of evolution of cross-resistance to ALS-inhibiting herbicides in B. tectorum. A single-point mutation, Ser653Asn, was identified, conferring the high-level resistance to imazamox. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A study was conducted for three seasons in northwest Kansas, USA to evaluate acetolactate synthase (ALS)-inhibiting herbicides for downy brome (Bromus tectorum L.) and winter annual broadleaf weed control in winter wheat. Herbicides included pyroxsulam at 18.4 g ai ha−1, propoxycarbazone-Na at 44 g ai ha−1, premixed propoxycarbazone-Na & mesosulfuron-methyl at 27 g ai ha−1, and sulfosulfuron at 35 g ai ha−1. The herbicides were applied postemergence in fall and spring seasons. Averaged over time of application, no herbicide controlled downy brome more than 78% in any year. When downy brome densities were high, control was less than 60%. Pyroxsulam controlled downy brome greater than or similar to other herbicides tested. Flixweed (Descurainia sophia L.), blue mustard [Chorispora tenella (Pallas) DC.], and henbit (Lamium amplexicaule L.) control did not differ among herbicide treatments. All herbicides tested controlled flixweed and blue mustard at least 87% and 94%, respectively. However, none of the herbicides controlled henbit more than 73%. Fall herbicide applications improved weed control compared to early spring applications; improvement ranged from 3% to 31% depending on the weed species. Henbit control was greatly decreased by delaying herbicide applications until spring compared to fall applications (49% vs. 80% control). Herbicide injury was observed in only two instances. The injury was ≤13% with no difference between herbicides and the injury did not impact final plant height or grain yield.

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State the United Kingdom, for the pesticide active substance pyroxsulam are reported. The context of the peer review was that required by Commission Regulation (EU) No 188/2011. The conclusions were reached on the basis of the evaluation of the representative uses of pyroxsulam as a herbicide on winter wheat, rye and triticale. The reliable endpoints concluded as being appropriate for use in regulatory risk assessment, derived from the available studies and literature in the dossier peer reviewed, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Highland barley is one of the few crops that can be grown at high elevations, making it a key resource within the Tibet Plateau. Weeds are a significant threat to highland barley production, and new herbicides and tolerant barley varieties are needed to control this ever-growing problem. A better understanding of existing herbicide resistance mechanisms is therefore needed. In this study, transcriptomic and metabolomic analyses were used to identify molecular and physiological changes in two highland barley genotypes with differing sensitivities to the herbicide pyroxsulam. We identified several stress-responsive metabolites, including flavonoids and antioxidants, which accumulated to significantly higher levels in the pyroxsulam-resistant genotype. Additionally, we found key genes in both the flavonoid biosynthesis pathway and the antioxidant system that were up-regulated in pyroxsulam-resistant barley. This work significantly expands on the current understanding of the molecular mechanisms underlying differing pyroxsulam tolerance among barley genotypes and provides several new avenues to explore for breeding or engineering tolerant barley., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Weng, Yan, Guo and Chen.)

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State the United Kingdom, for the pesticide active substance pyroxsulam are reported. The context of the peer review was that required by Commission Regulation (EU) No 188/2011. The conclusions were reached on the basis of the evaluation of the representative uses of pyroxsulam as a herbicide on winter wheat, rye and triticale. The reliable endpoints concluded as being appropriate for use in regulatory risk assessment, derived from the available studies and literature in the dossier peer reviewed, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified. [ABSTRACT FROM AUTHOR]

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State the United Kingdom, for the pesticide active substance pyroxsulam are reported. The context of the peer review was that required by Commission Regulation (EU) No 188/2011. The conclusions were reached on the basis of the evaluation of the representative uses of pyroxsulam as a herbicide on winter wheat, rye and triticale. The reliable endpoints concluded as being appropriate for use in regulatory risk assessment, derived from the available studies and literature in the dossier peer reviewed, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified. [ABSTRACT FROM AUTHOR]

Wheat shows selectivity to pyroxsulam, a new broad-spectrum herbicide with high activity on blackgrass. Studies were performed to establish whether uptake, translocation or metabolism were responsible for the differential activity in wheat compared with blackgrass. In addition, the effect of the safener cloquintocet-mexyl on metabolism was evaluated in wheat and blackgrass shoots. Root uptake of pyroxsulam in blackgrass was significantly higher than in wheat, suggesting a possible activity enhancement in blackgrass owing to root uptake. Translocation to foliage from root uptake as well as translocation out of treated foliage following foliar applications was low in wheat compared with blackgrass, likely owing to the rapid metabolism of pyroxsulam in wheat. Wheat metabolized pyroxsulam significantly faster than blackgrass to the less active O-dealkylation product. Wheat shoots metabolized pyroxsulam faster when the safener cloquintocet-mexyl was present, but cloquintocet-mexyl did not increase the rate of metabolism in blackgrass. The selectivity of pyroxsulam to wheat relative to blackgrass was connected primarily with differences in the rate of metabolism and generation of an inactive metabolite. Metabolism in wheat restricted subsequent movement of radioactivity out of the treated leaf. The rapid metabolism in wheat was increased by the addition of cloquintocet-mexyl. Copyright © 2010 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Green foxtail [Setaria viridis (L) Beauv.] and yellow foxtail [Setaria pumila (Poir.) Roem. & Schult.] are among the most abundant and troublesome annual grass weeds in cereal crops in the Northern Plains of the United States and the Prairie Provinces of Canada. Greenhouse and laboratory experiments were conducted to examine the differential responses of both weed species to foliar applications of the new triazolopyrimidine sulfonamide acetolactate synthase-inhibiting herbicide, pyroxsulam, and to determine the mechanism(s) of differential weed control. Foliar applications of pyroxsulam resulted in >90% control of yellow foxtail at rates between 7.5 and 15 g ai ha -1 , whereas the same rates resulted in a reduced efficacy on green foxtail (≤81%). The absorption and translocation of [ 14 C]pyroxsulam in green and yellow foxtail were similar and could not explain the differential whole-plant efficacy. Studies with [ 14 C]pyroxsulam revealed a higher percentage of absorbed pyroxsulam was metabolized into an inactive metabolite in the treated leaf of green foxtail than in the treated leaf of yellow foxtail. Metabolism studies demonstrated that, 48 h after application, 50 and 35% of pyroxsulam in the treated leaf was converted to 5-hydroxy-pyroxsulam in green and yellow foxtail, respectively. The acetolactate synthase (ALS) inhibition assay showed that ALS extracted from green foxtail was more tolerant to pyroxsulam than the enzyme extracted from yellow foxtail was. The in vitro ALS assay showed IC 50 values of 8.39 and 0.26 μM pyroxsulam for green and yellow foxtail, respectively. The ALS genes from both green and yellow foxtail were sequenced and revealed amino acid differences; however, the changes are not associated with known resistance-inducing mutations. The differential control of green and yellow foxtail following foliar applications of pyroxsulam was attributed to differences in both metabolism and ALS sensitivity.