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The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Austria and co‐rapporteur Member State Finland for the pesticide active substance fenoxaprop‐P‐ethyl are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative uses of fenoxaprop‐P‐ethyl as a post‐emergence herbicide in wheat, durum wheat, rye, triticale and barley to control annual monocotyledonous weeds. The reliable end points, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified. [ABSTRACT FROM AUTHOR]

Fenoxaprop-P-ethyl (FE) can effectively control weeds in rice fields, but it has been found to cause phytotoxicity in rice. In this study, the phytotoxicity of FE was mitigated by perilla leaf essential oil (PEO) in rice seedlings. The injury recovery rates (IRRs) for shoot length and fresh weight treated with 800 mg/L of PEO were 101.51% and 99.05%, respectively. Moreover, the damage of s-metolachlor and pretilachlor was also alleviated when co-applied with 800 mg/L PEO; the IRR of s-metolachlor phytotoxicity was 26.07% and 27.34%, respectively, and the IRR of pretilachlor phytotoxicity was 127.27% and 124.39%, respectively. However, PEO had no significant effect on the phytotoxicity of pinoxaden, mesotrione, penoxsulam, mesosulfuron-methyl, and nicosulfuron. The results of GC–MS analysis showed that a total of 23 components were detected in PEO, among which linalool (36.49%), linalyl formate (26.96%), α-terpineol (10.63%), 2-hexanoylfuran (5.81%), geranyl acetate (4.13%), and neryl acetate (2.30%) were the primary components. Among them, 2-hexanoylfuran was the most effective component to alleviate FE damage, for which the IRR of shoot length and fresh weight was 73.17% and 73.02%, respectively, followed by the geranyl acetate, for which the IRR was 72.32% and 60.56%, respectively, and neryl acetate, for which the IRR was 65.28% and 58.11%, respectively. Furthermore, the application of 50 mg/L of 2-hexanofuran significantly improved the tolerance of shoot length and fresh weight to FE stress by factors of 5.32 and 5.35, respectively. This research demonstrates that PEO and 2-hexanoylfuran have the potential to serve as natural safeners to reduce phytotoxicity. [ABSTRACT FROM AUTHOR]

Abstract The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Austria and co‐rapporteur Member State Finland for the pesticide active substance fenoxaprop‐P‐ethyl are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative uses of fenoxaprop‐P‐ethyl as a post‐emergence herbicide in wheat, durum wheat, rye, triticale and barley to control annual monocotyledonous weeds. The reliable end points, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Fenoxaprop-p-ethyl (FE) is one of the typical aryloxyphenoxypropionate herbicides. FE has been widely applied in agriculture in recent years. Human health and aquatic ecosystems are threatened by the cyanobacteria blooms caused by Microcystis aeruginosa, which is one of the most common cyanobacteria responsible for freshwater blooming. Few studies have been reported on the physiological effects of FE on M. aeruginosa. This study analyzed the growth curves, the contents of chlorophyll a and protein, the oxidative stress, and the microcystin-LR (MC-LR) levels of M. aeruginosa exposed to various FE concentrations (i.e., 0, 0.5, 1, 2, and 5 mg/L). FE was observed to stimulate the cell density, chlorophyll a content, and protein content of M. aeruginosa at 0.5- and 1-mg/L FE concentrations but inhibit them at 2 and 5 mg/L FE concentrations. The superoxide dismutase and catalase activities were enhanced and the malondialdehyde concentration was increased by FE. The intracellular (intra-) and extracellular (extra-) MC-LR contents were also affected by FE. The expression levels of photosynthesis-related genes psbD1, psaB, and rbcL varied in response to FE exposure. Moreover, the expressions of microcystin synthase-related genes mcyA and mcyD and microcystin transportation-related gene mcyH were significantly inhibited by the treatment with 2 and 5 mg/L FE concentrations. These results might be helpful in evaluating the ecotoxicity of FE and guiding the rational application of herbicides in modern agriculture. [ABSTRACT FROM AUTHOR]

Fenoxaprop-P-ethyl (FE) can effectively control weeds in rice fields, but it has been found to cause phytotoxicity in rice. In this study, the phytotoxicity of FE was mitigated by perilla leaf essential oil (PEO) in rice seedlings. The injury recovery rates (IRRs) for shoot length and fresh weight treated with 800 mg/L of PEO were 101.51% and 99.05%, respectively. Moreover, the damage of s-metolachlor and pretilachlor was also alleviated when co-applied with 800 mg/L PEO; the IRR of s-metolachlor phytotoxicity was 26.07% and 27.34%, respectively, and the IRR of pretilachlor phytotoxicity was 127.27% and 124.39%, respectively. However, PEO had no significant effect on the phytotoxicity of pinoxaden, mesotrione, penoxsulam, mesosulfuron-methyl, and nicosulfuron. The results of GC–MS analysis showed that a total of 23 components were detected in PEO, among which linalool (36.49%), linalyl formate (26.96%), α-terpineol (10.63%), 2-hexanoylfuran (5.81%), geranyl acetate (4.13%), and neryl acetate (2.30%) were the primary components. Among them, 2-hexanoylfuran was the most effective component to alleviate FE damage, for which the IRR of shoot length and fresh weight was 73.17% and 73.02%, respectively, followed by the geranyl acetate, for which the IRR was 72.32% and 60.56%, respectively, and neryl acetate, for which the IRR was 65.28% and 58.11%, respectively. Furthermore, the application of 50 mg/L of 2-hexanofuran significantly improved the tolerance of shoot length and fresh weight to FE stress by factors of 5.32 and 5.35, respectively. This research demonstrates that PEO and 2-hexanoylfuran have the potential to serve as natural safeners to reduce phytotoxicity.

Fenoxaprop-p-ethyl (FEN) is an aryloxy phenoxy propionate herbicide that has been widely used in paddy fields. Previous studies have indicated that FEN is highly toxic to aquatic organisms, but little is known about the developmental effects of FEN. This study investigated acute and developmental toxicity, malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase (CAT) activities, and metabolomic analyses in zebrafish embryos after 96 h of exposure. FEN exhibited high acute toxicity to zebrafish embryos and larvae. Exposure to FEN could reduce heartbeat and hatching rates and increase malformation rates in embryos. Oxidative damage was also caused in embryos. The results of metabolomics analysis showed that 102 differentially abundant metabolites were found in zebrafish embryos in the 0.05 mg/L FEN treatment group, and 60 differentially abundant metabolites were found in the 0.20 mg/L FEN treatment group. These differentially abundant metabolites mainly belonged to 9 metabolic pathways, of which folate pathways and ABC transport protein pathways had the greatest impact. These results suggested that FEN induced high acute and developmental toxicity in zebrafish embryos. [ABSTRACT FROM AUTHOR]

BACKGROUND: The use of herbicide safeners effectively minimises crop damage while maintaining the full efficacy of herbicides. The present study aimed to assess the potential protective effects of neral (NR) as a safener, in order to mitigate injury caused by fenoxaprop‐p‐ethyl (FE) on rice. RESULTS: The alleviating effect of NR was similar to that of the safener isoxadifen‐ethyl (IE). The root elongation of rice was significantly promoted under the FE + NR and FE + IE treatments, as compared to the FE treatment. The transcriptome analysis further suggested that the effects of NR treatment on plant metabolic pathways differed from those of IE treatment. In total, 895 and 47 up‐differentially expressed genes induced by NR (NR‐inducible genes) and IE (IE‐inducible genes) were identified. NR‐inducible genes were mainly enriched in phytohormone synthesis and signalling response, including 'response to brassinosteroid', 'response to jasmonic acid', 'response to ethylene', 'brassinosteroid metabolic process', 'brassinosteroid biosynthesis' and 'plant hormone signal transduction'. In contrast, IE‐inducible genes were predominantly enriched in glutathione metabolism. The activity of glutathione S‐transferase was found to be increased after IE treatment, whereas no significant increase was observed following NR treatment. Moreover, several transcription factor genes, such as those encoding AP2/ERF‐ERF and (basic helix–loop–helix) bHLH were found to be significantly induced by NR treatment. CONCLUSION: This is the first report of the utilisation of NR as an herbicide safener. The results of this study suggest the toxicity of FE to rice is mitigated by NR through a distinct mechanism compared to IE. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In 35 years of routine screening for herbicide resistance, a total of 3758 seed sample/herbicide combinations were assayed. Resistance testing was done in either pots in glasshouses (chlortoluron, fenoxaprop and mesosulfuron‐methyl + iodosulfuron‐methyl sodium) or Petri‐dishes in incubators (sethoxydim, cycloxydim and pendimethalin). With all herbicides, the relationship between herbicide efficacy and year of sampling was linear, with the slope representing the annual loss of efficacy. This was higher for the ALS inhibitors mesosulfuron + iodosulfuron (3.73% year−1) and ACCase inhibitors sethoxydim/cycloxydim (1.92% year−1) and fenoxaprop (1.36% year−1) than for the substituted urea chlorotoluron (0.69% year−1) and the dinitroaniline pendimethalin (1.10% year−1). These results are consistent with other studies on the relative resistance risk associated with these different modes of action. There was also a surprisingly good correlation between results for random and non‐random resistance testing, which has also been found in studies with other weed species in Canada and Australia. This indicates that routine testing of submitted samples can replace, at least partly, the need for random surveys which tend to be both labour intensive and expensive. These results, compiled over 35 years, show the value of routine resistance screening, not only for detecting resistance at the individual field level ('micro' scale), but also the distribution, evolution and impact of resistance country‐wide ('macro' scale). However, it is important that standardised testing methods, including appropriate reference populations, are used by different testing centres to ensure consistent results. [ABSTRACT FROM AUTHOR]

In order to clarify the resistance status of Alopecurus aequalis to acetyl-CoA carboxylase (ACCase)-inhibiting herbicides, 30 populations of A. aequalis were collected from rice-wheat rotation fields in Anhui Province and determined by whole plant bioassay of resistance levels to three ACCase herbicides, including fenoxaprop-P-ethyl, clodinafop-propargyl and pinoxaden. Seven kinds of postemergence herbicides such as tralkoxydim and pyroxsulam were selected for the boi-activity test to highly resistant population AHCZ-2. Five herbicides mixed with isoproturon were employed for the field efficacy evaluation. The results showed that among 30 tested populations, 26 populations were highly resistant to fenoxaprop-P-ethyl, accounting for 86.67% of the total tested populations. The GR50 value (active ingredients, the same as below) was 230.93-1755.54 g/hm², and resistance index (RI) was 12.58-95.66. Twenty-one populations were highly resistant to clodinafop-propargyl, accounting for 70% of the total tested populations. The GR50 value was 147.18-1213.44 g/hm², and RI was 11.93-98.36. The 19 populations were highly resistant to pyraclostrobin, accounting for 63.33% of the total tested. The GR50 value ranged from 107.63 to 614.18 g/hm², and RI ranged from 12.21 to 69.69. The resistance of A. aequalis populations collected from the same area to three kinds of ACCases inhibitors was similar. Among the 7 kinds of post-emergence herbicides tested, the activity to highly resistant A. aequalis population AHCZ-2 was higher in tralkoxydim and chlortoluron with GR90 of 468.74 g/hm² and 1495.85 g/hm², followed by cypyrafluone-isoproturon with the GR90 of 1035.62 g/hm² . The activity of isoproturon, pyroxsulam, mesosulfuron-methyl and flucarbazone-Na was low. The field screening results showed that recommended high dose mesosulfuron-methyl (15.75 g/hm² ), pyroxsulam (15 g/hm2 ) and chlortoluron (2250 g/hm² ) mixed with isoproturon at 1500 g/hm2 had the best control efficacy on A. aequalis. The plant control efficacy was between 91.18% and 94.05%, and the fresh weight control efficacy was between 92.40% and 95.68%, the yield increased by 25.04%-35.08%. Cypyrafluone-isoproturon at 937.5 g/hm² was the next with 90.78% control efficacy of fresh weight and yield increase of 22.78%. The results can provide reference for chemical control of rice-wheat field resistance A. aequalis. [ABSTRACT FROM AUTHOR]

Jute is a healthy vegetable due to its high content of carotenoids, vitamins, and minerals, in addition to its industrial utility. The purpose of this study was to look into the dissipation of fenoxaprop-p-ethyl and to track indirect sources of pesticide accumulation in jute ecosystems for three years in a row during tropical monsoon seasons. To avoid the intake of residues over approved limits, a rapid extraction technique was developed to evaluate the residues of this herbicide (Whip-Super 9% EC) in jute leaves, fiber, cropped soil, and water. A modified QuEChERS approach based on liquid chromatography and ultraviolet–visible (UV–VIS) detection was developed and successfully validated in accordance with SANCO requirements. Gas chromatography mass spectrometer (GC–MS) was used to examine fish and water samples from jute fields and retting pond for twenty widely-used multi-class pesticide contaminations from indirect sources. Relative standard deviations (RSD) (≤ 20) and recoveries (100–115%) are observed to be within acceptable ranges. In edible jute leaves, independent of season, first-order kinetics of dissipation was recorded, with half-lives ranging from 0.61 to 0.68 days. Based on the findings of the risk assessment, it is feasible to conclude that the consumer health risks of ingesting jute leaves are insignificant, even on day zero, when used at the recommended amount, and that using jute bags for food packaging and storage is safe. But jute field water was found to be less polluted with indirect pesticides than water from a nearby jute retted pond. Fish samples from this jute retted pond were also analyzed and found to be 26% contaminated. The presence of quinalphos and chlorpyriphos in jute retting water and fish might pose a concern to consumer health and environmental ecosystems. [ABSTRACT FROM AUTHOR]

Effective broad-spectrum herbicides are needed to address the issues of herbicide resistance and weed shifts in common cropping systems. A field experiment was conducted in 2016 and 2017 in West Bengal, India to compare the performance of three post-emergence herbicides (bispyribac-sodium; fenoxaprop-p-ethyl; penoxsulam) in monsoon rice (Oryza sativa L.) and their residual effects on succeeding rapeseed (Brassica rapa L.). Rice yield loss due to competition with Echinochloa colona (L.) Link, Leersia hexandra Sw., Cyperus iria L., Ludwigia parviflora L., and Monochoria vaginalis (Burm f.) C. Presl. Ex Kunth was 64% compared with weed-free control. Bispyribac-sodium 10% SC applied at 30 g a.i. ha−1 20 days after transplanting reduced weed density over the weedy control, ranging from 37% (M. vaginalis) to 87% (L. hexandra). Fenoxaprop-p-ethyl and penoxsulam applied, respectively, at 86 and 20 g a.i. ha−1 were effective in controlling grasses, but less effective against sedges and broadleaves. Bispyribac-sodium application resulted in highest rice yield (5.45 t ha−1), net return (Indian Rupees 42,677 ha−1), and benefit cost ratio (1.72). Bispyribac-sodium had neither adverse effect on soil microbes nor phytotoxic effect on rice and subsequent rapeseed. We recommend bispyribac-sodium for weed control in transplanted rice under rice-rapeseed system in eastern India. [ABSTRACT FROM AUTHOR]

Alopecurus japonicus has been a serious weed across China and developed resistance to the acetyl-CoA carboxylase (ACCase)-inhibiting herbicide. The A. japonicus ACCase gene mutations accounting for target-site resistance (TSR) have been clarified, while non-target-site resistance (NTSR) is not distinct. Here, dose–response testing indicated that an A. japonicus population (R) was resistant to four ACCase-inhibiting herbicides fenoxaprop-P-ethyl, sethoxydim, clethodim, and pinoxaden. Compared with herbicide-susceptible A. japonicus (S), no known resistant mutations for TSR in ACCase were identified in the R population using sequencing. To investigate the NTSR mechanism, increased metabolism of fenoxaprop-P-ethyl was detected in the R population using high-performance liquid chromatography (HPLC) analysis. Notably, resistance cannot be reversed by P450 and GST inhibitors. RNA-seq was performed to further explore the resistance mechanisms, and eight candidate contigs (four glycosyl transferases (GT) and four ATP-binding cassette (ABC) transporters) were chosen and their expression patterns were validated using RT-qPCR. Three GT and three ABC transporter contigs were constitutively upregulated in the R population. In short, six contigs expressed highly in the R population causing enhanced fenoxaprop-P-ethyl metabolism appear to be involved in fenoxaprop-P-ethyl resistance. [ABSTRACT FROM AUTHOR]

Weed management is the major biological constraint in paddy (Oryza sativa L.) producing areas. Predominantly, barnyard grass (Echinochloa crus-galli) is a rice-mimicking weed that causes 57% of yield loss in rice production. Conventionally, herbicides are the site-specific weed inhibitors often used to suppress E. crus-galli growth. Acetyl-CoA carboxylase (ACCase) is an important target for developing novel herbicides with remarkable selectivity against gramineous weeds. Notably, fenoxaprop-P-ethyl (FPPE) is a selective ACCase herbicide extensively used in paddy fields to inhibit barnyard grass. However, prolonged use of FPPE herbicide elicits phytotoxicity in cultivated rice and herbicide resistance in weeds. Recently, phytotoxins are emerging as an alternative to commercial herbicides with safer environmental profiles. Nevertheless, discovering natural herbicides through in vivo and in vitro techniques is time-consuming and expensive. Therefore, high-end computational screening strategies including Tanimoto similarity, docking, binding free energy, and herbicide-likeness were used to pinpoint the lead molecule. Finally, molecular dynamics and MM/PBSA calculations were employed to validate the binding kinetics of the hit compound. Indeed, sinigrin was identified as a promising phytotoxic inhibitor against the ACCase enzyme. The findings of our study were well correlated with the existing experimental results. Overall, the current work will aid in the development of commercializing phytotoxin herbicides in foreseeable future. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the effects of sublethal concentration of herbicide Fenoxaprop-Pethyl on freshwater edible fish Cyprinus carpio. Fishes exposed to a sublethal concentration of herbicide (37.5 µg L-1) for 15, 30, and 45 days following the semi-static bioassay method. Haematological and histopathological studies were carried out to evaluate the effects on the vital organs, including the liver, kidney, and gills. Haematological indices such as red blood cells (RBC), haemoglobin, lipid profile, liver function tests, and kidney function tests varied with increasing exposure period. Histopathological alterations revealed hyperplasia, telangiectasia, epithelial separation, and destruction of secondary lamellae in the gills of herbicide-exposed fishes. The liver showed vacuolation, necrosis, nuclear degeneration, and blood infiltration. The kidney exhibited dilated Bowman’s space, haematopoietic necrosis, tubular necrosis, pyknosis, and dilated tubules. The histo-architectural changes were directly dependent on the duration of exposure and manifested an increased detrimental effect on the physiology of the fish Cyprinus carpio.

[Display omitted] • The solubility of fenoxaprop-p-ethyl in various aqueous mixtures was determined. • Three thermodynamic classical models were utilized to correlate the solubility. • Solvent effects in terms of molecular interactions was implemented through MLRA. • Preferential solvation of fenoxaprop-p-ethyl was investigated by IKBI method. Equilibrium solubility of fenoxaprop-p-ethyl in aqueous mixtures of ethanol/ isopropanol/acetonitrile/ N,N -dimethylformamide (DMF) plus water was experimentally measured by isothermal saturation method at (278.15–323.15) K under 101.2 kPa. The order of solubility (mole fraction) of fenoxaprop-p-ethyl in pure solvents from high to low is 4.233 × 10−2 (DMF 323.15 K) > 2.044 × 10−2 (acetonitrile 323.15 K) > 7.727 × 10−3 (isopropanol 323.15 K) > 5.338 × 10−3 (ethanol 323.15 K) > 2.565 × 10−5 (water 323.15 K). Experimental results showed that temperature and type of solvent were decisive factors for the dissolution of fenoxaprop-p-ethyl. The content of fenoxaprop-p-ethyl in solution was analyzed by high-performance liquid chromatography (HPLC). Moreover, the solubility data of fenoxaprop-p-ethyl was correlated by Jouyban-Acree (J-A) model, van't Hoff-Jouyban-Acree (V-J-A) model and Apelblat-Jouyban-Acree (A-J-A) model. The maximum of root-mean-square deviation (RMSD), relative average deviation (RAD) and standard deviation (SD) predicted via three thermodynamic models were 1.78 × 10−4 (DMF + water), 2.87 × 10−2 (acetonitrile + water) and 1.79 × 10−4 (DMF + water), respectively. In addition, the solvent effect between solute and solvent molecules was deduced by KAT-LSER model and the result showed that dipolarity/polarizability interactions between the solute and solvent molecules were dominant in the dissolution of fenoxaprop-p-ethyl. Finally, the preferential solvation parameter (δx 1,3) of fenoxaprop-p-ethyl was obtained by the method of inverse Kirkwood–Buff integrals and the preferential dissolution behavior of each concentration range is explained by Lewis acid base theory. However, for acetonitrile + water, the change of δx 1,3 may be due to the polarization effects and it is not suitable for Lewis acid base theory. [ABSTRACT FROM AUTHOR]

New solutions in plant protection applications are still highly desirable. Aiming at higher efficiency, environmental safety and profitability of production which, in addition to reducing the costs of the application of plant protection products, limits the destruction of soil structure combined use of agrochemicals seems to be one of the most important method in modern agriculture. In 2016 and 2017, the Plant Protection Institute – National Research Institute in Poznań, Poland, conducted field experiments on the possibility of combining two popular herbicides used to control monocotyledonous weeds: pinoxaden and fenoxaprop-P-ethyl, with a two-component plant growth and development regulator (mepiquat chloride and prohexadione calcium) on KWS Ozon winter wheat. The tested substances were applied at the BBCH 24 stage of winter wheat – herbicide only, and at the BBCH 31 stage – a mix of herbicides with a plant growth and development regulator. Regardless of the method of application of pinoxaden (herbicide only or mixed), high effectiveness of Apera spica-venti control was obtained in both years of the study. The mix of pinoxaden with mepiquat chloride and prohexadione calcium reduced the wheat crop height to a similar extent as separate application of the substances. The combined application of fenoxaprop-P-ethyl with mepiquat chloride improved the effectiveness of wheat crop height control. The method of application of the substances had no significant effect on winter wheat yield. Grain yields harvested from plots treated with the above substances were significantly higher than control only in the case of high weed infestation of winter wheat. The technological value of wheat grain depended on the year of study, while the method of application did not have a significant impact on the evaluated parameters.

Alopecurus japonicus has been a serious weed across China and developed resistance to the acetyl-CoA carboxylase (ACCase)-inhibiting herbicide. The A. japonicus ACCase gene mutations accounting for target-site resistance (TSR) have been clarified, while non-target-site resistance (NTSR) is not distinct. Here, dose–response testing indicated that an A. japonicus population (R) was resistant to four ACCase-inhibiting herbicides fenoxaprop-P-ethyl, sethoxydim, clethodim, and pinoxaden. Compared with herbicide-susceptible A. japonicus (S), no known resistant mutations for TSR in ACCase were identified in the R population using sequencing. To investigate the NTSR mechanism, increased metabolism of fenoxaprop-P-ethyl was detected in the R population using high-performance liquid chromatography (HPLC) analysis. Notably, resistance cannot be reversed by P450 and GST inhibitors. RNA-seq was performed to further explore the resistance mechanisms, and eight candidate contigs (four glycosyl transferases (GT) and four ATP-binding cassette (ABC) transporters) were chosen and their expression patterns were validated using RT-qPCR. Three GT and three ABC transporter contigs were constitutively upregulated in the R population. In short, six contigs expressed highly in the R population causing enhanced fenoxaprop-P-ethyl metabolism appear to be involved in fenoxaprop-P-ethyl resistance.

Weed management is the major biological constraint in paddy (Oryza sativa L.) producing areas. Predominantly, barnyard grass (Echinochloa crus-galli) is a rice-mimicking weed that causes 57% of yield loss in rice production. Conventionally, herbicides are the site-specific weed inhibitors often used to suppress E. crus-galli growth. Acetyl-CoA carboxylase (ACCase) is an important target for developing novel herbicides with remarkable selectivity against gramineous weeds. Notably, fenoxaprop-P-ethyl (FPPE) is a selective ACCase herbicide extensively used in paddy fields to inhibit barnyard grass. However, prolonged use of FPPE herbicide elicits phytotoxicity in cultivated rice and herbicide resistance in weeds. Recently, phytotoxins are emerging as an alternative to commercial herbicides with safer environmental profiles. Nevertheless, discovering natural herbicides through in vivo and in vitro techniques is time-consuming and expensive. Therefore, high-end computational screening strategies including Tanimoto similarity, docking, binding free energy, and herbicide-likeness were used to pinpoint the lead molecule. Finally, molecular dynamics and MM/PBSA calculations were employed to validate the binding kinetics of the hit compound. Indeed, sinigrin was identified as a promising phytotoxic inhibitor against the ACCase enzyme. The findings of our study were well correlated with the existing experimental results. Overall, the current work will aid in the development of commercializing phytotoxin herbicides in foreseeable future.

The present study aimed to investigate the effects of sublethal concentration of herbicide Fenoxaprop-Pethyl on freshwater edible fish Cyprinus carpio. Fishes exposed to a sublethal concentration of herbicide (37.5 µg L-1) for 15, 30, and 45 days following the semi-static bioassay method. Haematological and histopathological studies were carried out to evaluate the effects on the vital organs, including the liver, kidney, and gills. Haematological indices such as red blood cells (RBC), haemoglobin, lipid profile, liver function tests, and kidney function tests varied with increasing exposure period. Histopathological alterations revealed hyperplasia, telangiectasia, epithelial separation, and destruction of secondary lamellae in the gills of herbicide-exposed fishes. The liver showed vacuolation, necrosis, nuclear degeneration, and blood infiltration. The kidney exhibited dilated Bowman's space, haematopoietic necrosis, tubular necrosis, pyknosis, and dilated tubules. The histo-architectural changes were directly dependent on the duration of exposure and manifested an increased detrimental effect on the physiology of the fish Cyprinus carpio. [ABSTRACT FROM AUTHOR]

Common roegneria, a perennial weed in Roegneria genera of the tribe Triticeae (family: Poaceae), is widely distributed in China and could not be effectively controlled by acetyl coA carboxylase (ACCase) inhibitors in wheat in some regions. This study aimed to quantify herbicide tolerance level and investigate its mechanisms of ACCase tolerance in common roegneria. Whole-plant dose–response assay indicated that populations ZJJX and HBJZ (collected in wheat fields) exhibited high tolerance [ED50s >16-fold labeled field rate (LFR)] to fenoxaprop-P-ethyl and clodinafop-propargyl [aryloxyphenoxypropionate (APPs)] and pinoxaden (phenylpyrazolin). In addition, two populations collected from uncultivated areas showed similar responses to these herbicides. All common roegneria populations were susceptible to haloxyfop-R-methyl and quizalofop-p-ethyl (APPs), clethodim, and sethoxydim (cyclohexanediones) (ED50s

The present study was undertaken to determine the acute toxicity of the herbicide Fenoxaprop-P-ethyl (FPE) and the resulting behavioral alterations in the exotic freshwater carp Cyprinus carpio. The experimental fish were divided into groups of 10 (n=10) and exposed to different concentrations of the test pesticide for 24, 48, 72, and 96 hours. The 96-hour LC50 was found to be 300 μg/l. Sub-lethal concentration was fixed based on LC50value is 37.5 μg/l (1/8th of LC50) of the herbicide FPE for a period of 45 days. Regular observation was made throughout the exposure period to determine the long-term behavioral changes in the test fish. The fish displayed erratic swimming behavior that increased over the days of exposure. Behavioral anomalies such as whirling cork movement, altered opercular movement, altered fin movement and physiological changes such as dyspigmentation and altered mucus secretion were observed. [ABSTRACT FROM AUTHOR]

BACKGROUND Non‐target‐site resistance (NTSR) to herbicides is a serious threat to global agriculture. Although metabolic resistance is the dominant mechanism of NTSR, the molecular mechanisms are not yet well‐characterized. This study aimed to uncover the likely metabolism‐related genes in Beckmannia syzigachne (American sloughgrass) resistant to fenoxaprop‐p‐ethyl. RESULTS: Ultra‐performance liquid chromatography – tandem mass spectrometry experiments showed that the resistant American sloughgrass biotype (R, SD‐04‐SS) showed enhanced degradation of this herbicide compared to the susceptible biotype (S, SD‐12). R and S biotype were harvested at 24 h after fenoxaprop‐p‐ethyl treatment to conduct RNA sequencing (RNA‐Seq) analysis to investigate the likely fenoxaprop‐p‐ethyl metabolic genes. The RNA‐Seq libraries yield 417 969 980 clean reads. The de novo assembly generated 115 112 unigenes, of which 57 906 unigenes were annotated. Finally, we identified 273 cytochrome P450s, 178 oxidases, 47 glutathione S‐transferases (GSTs), 166 glucosyltransferases (GTs) and 180 ABC transporter genes to determine the likely fenoxaprop‐p‐ethyl metabolism‐related genes in R biotype. Twelve overlapping up‐regulated genes in the R biotype (fenoxaprop‐p‐ethyl‐treated R/non‐treated R, fenoxaprop‐p‐ethyl‐treated R/fenoxaprop‐p‐ethyl‐treated S) were identified by RNA‐Seq and the results were validated using qRT‐PCR. Ten were identified as fenoxaprop‐p‐ethyl metabolism‐related genes, including three P450s (homologous to CYP71D7, CYP99A2 and CYP71D10), one GST (homologous to GSTF1), two GTs (homologous to UGT90A1 and UGT83A1) and four oxidase genes. CONCLUSION: This work demonstrates that the NTSR mechanism by means of enhanced detoxification of fenoxaprop‐p‐ethyl in American sloughgrass is very likely driven by herbicide metabolism related genes. The RNA‐Seq data presented here provide a valuable resource for understanding the molecular mechanism of NTSR in American sloughgrass. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: The purpose of the present study was to develop ecofriendly herbicide formulations. Its main aim was to develop and investigate slow‐release formulations of herbicides (metribuzin, tribenuron‐methyl, and fenoxaprop‐P‐ethyl) of different structure, solubility, and specificity, which were loaded into a degradable matrix of poly‐3‐hydroxybutyrate (P(3HB)) blended with available natural materials (peat, clay, and wood flour). RESULTS: Differences in the structure and physicochemical properties of the formulations were studied depending on the type of the matrix. Herbicide release and accumulation in soil were associated with the solubility of the herbicide. Fourier‐transform infrared spectroscopy showed that no chemical bonds were formed between the components in the experimental formulations. Degradation of the formulations in agro‐transformed soil in laboratory conditions was chiefly influenced by the shape of the specimens (granules or pellets) while the effect of the type of filler (peat, clay, or wood flour) was insignificant. The use of granules enabled more rapid accumulation of the herbicides in soil: their peak concentrations were reached after 3 weeks of incubation while the concentrations of the herbicides released from the pellets were the highest after 5–7 weeks. Loading of the herbicides into the polymer matrix composed of the slowly degraded P(3HB) and natural materials enabled both sustained function of the formulations in soil (lasting between 1.5 and ≥3 months) and stable activity of the otherwise rapidly inactivated herbicides such as tribenuron‐methyl and fenoxaprop‐P‐ethyl. CONCLUSION: The experimental herbicide formulations enabled slow release of the active ingredients to soil. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Whole-plant response experiments in pots and field experiments over two years were conducted to study the resistance levels and chemical control options of sterile oat (Avena sterilis L.) in typical wheat production areas of northern Greece. Data revealed high levels of resistance to the ACCase-inhibiting herbicides clodinafop-propargyl and fenoxaprop-p-ethyl in all sterile oat populations, noticeable levels of resistance of some populations to tralkoxydim and pinoxaden, and high susceptibility of four out of the five populations to the prepackage mixture [mesosulfuron + iodosulfuron]. The addition of chlorpyrifos did not improve the efficacy of all herbicides against the resistant populations, implying target-site resistance in the populations tested rather than resistance due to P450-mediated enhanced herbicide metabolism. These results indicated that all populations were at least four times more resistant to clodinafop-propargyl, fenoxaprop-p-ethyl and diclofop-methyl than the susceptible populations, but noticeable levels of resistance of some sterile oat populations to tralkoxydim, pinoxaden and the prepackage mixture [mesosulfuron + iodosulfuron] were also recorded. However, viable options for chemical control of this weed still exist. [ABSTRACT FROM AUTHOR]

The resistant level, mechainism of resistance of Alopecurus myosuroides against fenoxaprop- P-ethyl were determined. Results of the whole-plant dose-response test showed that population HN-05 from Henan Province had evolved high-level resistance against fenoxaprop-P-ethyl (52.2-fold). Using the gene sequencing method, two amino acid mutations at codon 2041 (Ile-Asn) and 2096 (Gly-Ala) were detected in the ACCase gene of the resistant population HN-05. Pre-treatment with the known metabolic inhibitor, piperonyl butoxide (PBO), enhanced the activity of fenoxaprop-P-ethyl (161.3- fold). So that the GR50 value (active ingredient) of fenoxaprop-P-ethyl to HN-05 is 5.4 g/hm2 . This study confirmed the resistance of A. myosuroides against the ACCase inhibitor, fenoxaprop-P-ethyl. The resistance mechanism were conferred by specific ACCase point mutations at amino acid position Ile-2041-Asn and Gly-2096-Ala and P450s-based metabolism. [ABSTRACT FROM AUTHOR]

Severe infestations of American sloughgrass (Beckmannia syzigachne (Steud.) Fernald) in wheat fields throughout Anhui Province, China, pose a significant threat to local agricultural production. This study aims to evaluate the susceptibility of 37 B. syzigachne populations collected from diverse wheat fields in Anhui Province to three commonly used herbicides: fenoxaprop- P -ethyl, mesosulfuron-ethyl, and isoproturon. Single-dose testing revealed that out of the 37 populations, 31, 26, and 11 populations had either evolved or were evolving resistance to fenoxaprop- P -ethyl, mesosulfuron-ethyl, and isoproturon, respectively. Among them, 25 populations displayed concurrent resistance to both fenoxaprop- P -ethyl and mesosulfuron-ethyl, while eight exhibited resistance to all three tested herbicides. Whole-plant bioassays confirmed that approximately 84% of the fenoxaprop- P -ethyl-resistant populations manifested high-level resistance (resistance index (RI) ≥10); 62% of the mesosulfuron-ethyl-resistant populations and 82% of the isoproturon-resistant populations exhibited low- to moderate-level resistance (2 ≤ RI <10). Three distinct target-site mutations were identified in 27% of fenoxaprop- P -ethyl-resistant populations, with no known resistance mutations detected in the remaining herbicide-resistant populations. The inhibition of cytochrome P450s (P450s) and/or glutathione S-transferases (GSTs) substantially increased susceptibility in the majority of resistant populations lacking mutations at the herbicide target site. In conclusion, resistance to fenoxaprop- P -ethyl and mesosulfuron-ethyl was widespread in B. syzigachne within Anhui Province's wheat fields, while resistance to isoproturon was rapidly evolving due to its escalating usage. Target-site mutations were present in approximately one-third of fenoxaprop- P -ethyl-resistant populations, and alternative mechanisms involving P450s and/or GSTs could explain the resistance observed in most of the remaining populations. [Display omitted] • ACCase and ALS resistance in B. syzigachne was prevalent across the wheat fields in Anhui. • PSII resistance was initially confirmed in some populations of B. syzigachne worldwide. • Common ACCase mutations were identified in some ACCase-resistant populations. • P450s/GSTs-involved resistance was present in populations lacking target-site mutations. [ABSTRACT FROM AUTHOR]

Introduction Soil herbicides residue in agroecosystems is one of the important problems due to herbicides application. However herbicides residue in soil extend the period of weed control. Nevertheless, it may persist longer than desired and injure subsequent crops in rotation. Herbicides vary in their potential to persist in the soil. Some herbicides such as sulfonylurea herbicides are very persistent. Among registered herbicides for weed control in wheat fields in Iran, Sulfonylurea (e.g. sulfosulfuron and metsulforon-methyl+sulfosulforon) and aryloxy phenoxy propionate (e.g. Diclofop-methyl, fenoxaprop-p-ethyl) are more important groups. With regard to the persistence of mentioned herbicides in soil, sulfonylurea herbicides may create problems in crop rotation. Since chickpea (Cicer arietinum L.) is one of important crops in rotation with wheat in Iran and the effect of sulfosulfuron, metsulforon-methyl+sulfosulforon, diclofop-methyl and fenoxaprop-p-ethyl on its growth, nodulation, and nitrogen fixation have not been studied yet. This study was conducted to investigate the effects of mentioned herbicides residue in soilon growth, nodulation, and nitrogen fixation of chickpea genotypes in controlled conditions. Material and Methods In order to study the effects of soil residue of some sulfonylurea and aryloxy phenoxy propionate herbicides on growth, nodulation and nitrogen fixation of chickpea (Cicer arietinum L.), a pot experiment was conducted using factorial arrangement in a completely randomized design with three replications. Factors included herbicide type in four levels (diclofop-methyl, fenoxaprop-p-ethyl, sulfosulfuron and metsulforon-methyl+sulfosulforon), herbicides residue in soil in eight levels (0, 2.5, 5, 10, 15, 20, 30, and 40 percent of recommended dose for each herbicide) and chickpea genotypes in three levels (Hashem, ILC 482, and KaKa). After mixing the herbicide solution with prepared soil and planting, plants were maintained until the beginning of reproductive stage. In the early stage of reproductive, shoot biomass and root biomass, number of root node and total nitrogen content of plants were measured. The data were statistically analyzed using variance analysis, and differences among mean values of treatments were compared by Duncan test (p≤0.05) in SAS. For determination the dose of herbicides required to reduce 50% of plants response (ED50), the dose response curves were fitted simultaneously using the following three-parameter logistic model. f(x,(b,d,e))= d/(1+exp⁡〖{b(log⁡(x)-log⁡〖(e))}〗 〗 ) Where f is the response (above ground dry weight, root dry weight and node dry weight), d is the upper limit, b is the curve slope, e denotes the dose required to give a response halfway between the upper and lower limits (ED50); and x is the herbicide concentration in soil. The validity of the above model and the comparison between the parameters were made using F-test for lack-of-fit with a 5% level of significance. Results and Discussion Results showed that sulfonylurea (sulfosulfuron and metsulforon-methyl+sulfosulforon) and aryloxy phenoxy propionate (diclofop-methyl, fenoxaprop-p-ethyl) had the highest and the lowest effect on mentioned traits of plants, respectively. By increasing of sulfonylurea herbicides residue in soil, all measured traits decreased significantly (p≤0.01). However, soil residue of aryloxy phenoxy propionates herbicides did not significantly affect on chickpea genotypes. The lowest ED50 (0.0025 mg kg-1 soil) and the highest ED50 (0.0047 mg kg-1 soil) of sulfosulfuron herbicide soil residue for shoot biomass, were observed in Hashem and ILC482 genotypes, respectively and the lowest ED50 (0.0057 mg kg-1 soil) and the highest ED50 (0.0837 mg kg-1 soil) of metsulforon-methyl+sulfosulforon herbicide soil residue, were observed in ILC482 and KaKa genotypes, respectively. Considering the results of the study, it can be noted that Hashem genotype showed more sensitivity to sulfosulfuron and metsulforon-methyl+sulfosulforon herbicides soil residue compared to the other genotypes. Generally, results of this experiment showed that soil residue of sulfosulfuron and metsulforon-methyl+sulfosulforon herbicides had significant and negative impact on chickpea growth. On the other hand, chickpea genotypes had different sensitivity to soil residue herbicides. Conclusion Results indicated that it is necessary to look the interval time in chickpea planting in rotation of wheat-chickpea. Moreover, selection of less sensitive chickpea genotypes to soil residue of sulfosulfuron and metsulforon-methyl+sulfosulforon herbicides could be useful in their residue management. Key words: Chickpea genotypes, Diclofop-methyl, Fenoxaprop-p-ethyl, Metsulforon-methyl+sulfosulforon, Sulfosulfuron

The dissipation kinetics of fenoxaprop-p-ethyl and its metabolite (fenoxaprop acid) at two application rates under wheat field conditions for two seasons was investigated. Herbicides were extracted by solid liquid extraction, cleaned up, and analyzed by a liquid chromatography–UV detector. Dissipation followed first-order kinetics; in soil, fenoxaprop-p-ethyl dissipated rapidly with an average half-life of 1.45 to 2.30 days, while fenoxaprop acid persisted for more than 30 days. The method was validated in terms of accuracy, linearity, specificity, and precision. Linearity was in the range of 5 to 5,000 ng, with a limit of detection (LOD) of 2 and 1 ng for fenoxaprop-p-ethyl and fenoxaprop acid, respectively. The quantitation limits in soil, grain, and straw were 5, 8, and 10 ng g−1 for fenoxaprop-p-ethyl and 5, 10, and 10 ng g−1 for fenoxaprop acid, respectively. Recovery in soil, grains, and straw ranged from 85.1 to 91.25%, 72.5 to 84.66%, and 77.64 to 82.24% for fenoxaprop-p-ethyl and 80.56 to 86.5%, 78 to 81.88%, and 75.2 to 79.68% for fenoxaprop acid, respectively. At harvest, no detectable residues of fenoxaprop-p-ethyl or acid were observed in soil, wheat grain, and straw samples. Owing to the short persistence under field conditions, fenoxaprop-p-ethyl is safe for use because parent and metabolite residues were below the European Union maximum residue limit and would not pose an adverse effect on the environment and human or animal foods. [ABSTRACT FROM AUTHOR]

New solutions in plant protection applications are still highly desirable. Aiming at higher efficiency, environmental safety and profitability of production which, in addition to reducing the costs of the application of plant protection products, limits the destruction of soil structure combined use of agrochemicals seems to be one of the most important method in modern agriculture. In 2016 and 2017, the Plant Protection Institute - National Research Institute in Poznań, Poland, conducted field experiments on the possibility of combining two popular herbicides used to control monocotyledonous weeds: pinoxaden and fenoxaprop-P-ethyl, with a two-component plant growth and development regulator (mepiquat chloride and prohexadione calcium) on KWS Ozon winter wheat. The tested substances were applied at the BBCH 24 stage of winter wheat - herbicide only, and at the BBCH 31 stage - a mix of herbicides with a plant growth and development regulator. Regardless of the method of application of pinoxaden (herbicide only or mixed), high effectiveness of Apera spica-venti control was obtained in both years of the study. The mix of pinoxaden with mepiquat chloride and prohexadione calcium reduced the wheat crop height to a similar extent as separate application of the substances. The combined application of fenoxaprop-P-ethyl with mepiquat chloride improved the effectiveness of wheat crop height control. The method of application of the substances had no significant effect on winter wheat yield. Grain yields harvested from plots treated with the above substances were significantly higher than control only in the case of high weed infestation of winter wheat. The technological value of wheat grain depended on the year of study, while the method of application did not have a significant impact on the evaluated parameters. [ABSTRACT FROM AUTHOR]

Japanese foxtail (Alopecurus japonicus) is a malignant grass weed mainly infesting winter wheat- and canola-growing fields in China. To determine the resistance level and the potential resistance mechanism of A. japonicus to fenoxaprop-p-ethyl, 10 populations of A. japonicus were collected from the wheat fields in Tianchang City, Anhui Province. Whole-plant dose-response experiments were performed to investigate the resistance 1evels of different populations to fenoxaprop-p-ethyl in the greenhouse. Partial sequences of acetyl-CoA carboxylase (ACCase) genes were subsequently amplified, sequenced, and compared between the resistant and susceptible plants. The results revealed that all 10 populations displayed high-level resistance to fenoxaprop-p-ethyl, and the resistance indices ranged from 30.50 to 58.55. Gene sequencing showed that the mutations of isoleucine (Ile) to leucine (Leu) at 1 781 position and tryptophan (Trp) to cysteine (Cys) at 2027 position existed in the ACCase genes of different populations, with eight of them had mutations at 1 781 position. Besides, all populations had mutant frequencies higher than 80%. Our results indicated that herbicide resistance has evolved to a severe stage in Anhui Province, considering that all 10 populations collected from different sites showed high-level resistance to fenoxaprop-p-ethyl. The Ile-1 781-Leu and Trp-2 027-Cys mutations in ACCase genes were very likely to be the key reasons which caused the fenoxaprop-p-ethyl resistance of A. japonicus populations. In addition, compared with 2 027 position, ACCase seems more prone to produce a mutation at 1 781 position in A. japonicus. [ABSTRACT FROM AUTHOR]

Alopecurus myosuroides seeds were sampled from 32 winter wheat fields from 2010 to 2014. Resistance to herbicides was detected in 17 A. myosuroides populations. In addition to single resistance to herbicides, cross-resistance and multiple resistance to acetolactate synthase (ALS)- and acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides were found. Application of sulfometuron and imazapyr was unable to control some of the resistant biotypes in this study. This result implies that resistance in these populations is due to a target site mechanism. The A. myosuroides biotypes resistant to ACCase-inhibiting herbicides varied in their responses to derivatives of aryloxy-phenoxy-propionic acid (FOPs), cyclohexanediones (DIMs) and phenylpyrazolines (DENs). Resistant biotypes of A. myosuroides that could not be controlled with fenoxaprop-P-ethyl (FOP) and pinoxaden (DEN) were controlled with clethodim (DIM).

ABSTRACT Hormetic effects of herbicides at ultra-low doses have been proved against range of crop species, although available data of herbicides hormesis about the weeds growth is very limited. This study investigates the promotive effect of low doses of fenoxaprop-Pethyl on growth and seed production of littleseed canarygrass and wild oat. Pot experiments were conducted twice in Wire House at Agronomic Research Area, University of Agriculture, Faisalabad, during 2014-15. Seven different concentrations of fenoxaprop-P-ethyl [0, 1, 3, 6, 9, 12 and 15 g a.i. ha-1] were applied as post emergence herbicide at 3-4 leaves stage of the weeds. Results revealed that increase in growth occurred within first two weeks after spraying at fenoxaprop-P-ethyl doses 1, 3 and 6 g a.i. ha-1. More growth stimulation as compared to all other treatments was observed at fenoxaprop-P-ethyl dose 6 g a.i. ha-1. This initial increase in growth sustains with time up to the maturity of both weeds and positively influences seeds production ability. Up to 28% and 17% increase in number of seeds per plants were occurred in littleseed canarygrass and wild oat, respectively. Doses above 6 g a.i. ha-1 negatively affect the weeds growth and seed production ability.

Abstract: BACKGROUND: Alopecurus japonicus is a serious grass weed species in wheat fields in eastern Asia, and has evolved strong resistance to acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicides. Although target‐site resistance (TSR) to ACCase inhibitors in A. japonicus has been reported, non‐target site resistance (NTSR) has not. This study investigated both TSR and NTSR in a fenoxaprop‐P‐ethyl‐resistant A. japonicus population (AHFD‐3), which was collected in Feidong County, Anhui Province, China. RESULTS: We found that AHFD‐3 exhibited high resistance to fenoxaprop‐P‐ethyl and low resistance to flucarbazone‐sodium. The sensitivity of AHFD‐3 to fenoxaprop‐P‐ethyl increased significantly after treatment with cytochrome P450 (P450) inhibitors; however, such synergies between P450 inhibitors and fenoxaprop‐P‐ethyl were not found in two control populations. Sequences of the entire carboxyltransferase domain of A. japonicus ACCase were obtained, and AHFD‐3 plants showed an Asp‐2078‐Gly substitution in the ACCase. With the derived cleaved amplified polymorphic sequence (dCAPS) method, we found that 85.4% of the plants of AHFD‐3 carried this mutation. The P450 content in AHFD‐3 plants was significantly higher than those of the two control populations after treatment with fenoxaprop‐P‐ethyl. Ten partial sequences of P450 genes in A. japonicus were cloned. Three P450 genes were up‐regulated 12 h after fenoxaprop‐P‐ethyl treatment, which were all from the P450 subfamily CYP72A. Moreover, a P450 gene from the P450 family CYP81 was up‐regulated after fenoxaprop‐P‐ethyl treatment in all populations studied. CONCLUSION: Fenoxaprop‐P‐ethyl resistance in AHFD‐3 plants was conferred by up‐regulation of cytochrome P450s in the CYP72A subfamily and target site mutation of the ACCase gene. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this study, we evaluated effects of fenoxaprop-p-ethyl herbicide on wheat ( Triticum aestivum L.). The wheat plants were grown in pots containing perlite. Fenoxaprop-p-ethyl was applied to adequately grown T. aestivum plants at determined doses (1 mM, 1.5 mM, 2.2 mM, 3.4 mM and 5.1 mM) via spraying. The effects of this herbicide on some antioxidant enzymes, lipid peroxidation, carotenoid, total chlorophyll and total phenolic were investigated on days 1, 5 and 10 following the application. Environmental pollutants cause oxidative stress, production of free radicals and changes in antioxidants. Synthesis of signal molecules such as salicylic acid (SA) is important for the stress response of plants. In addition to this, although selenium is known not to be an obligatory element for plants, low dose selenium has positive effects on the plant growth. We also investigated the effects that are elicited on parameters above mentioned by the treatment of exogenous 0.5 mM SA and 0.004 mM organic selenium (SeI) separately. Our findings reveal that SA and SeI, which are externally applied before the germination of seeds that are exposed to herbicide stress, becomes effective in reduction of the negative effects of fenoxaprop-p-ethyl, with regard to antioxidant system, lipid peroxidation, pigment system and total phenolic. When we evaluate the study results, our findings suggest that especially SA plays a protective role on wheat against herbicide stress. [ABSTRACT FROM AUTHOR]

Si application alleviates influence of some abiotic stresses on crop plants. Meanwhile, scarce information is avaiable about the significance of Si for helping the plants to overcome the injuries of N deficiency and herbicides pressure. Thus, two–year 2–field experiments were carried out in wheat. Experiment I involved three Si concentrations (Si0ppm, Si250ppm and Si500ppm) and two N levels(N100% and N50%). Experiment II examined four combinations of fenoxaprop–p–ethyl and Si: fenoxaprop–p–ethyl+Si250ppm and fenoxaprop–p–ethyl+Si500ppm (each either in sequence or in tank mixture), fenoxaprop–p–ethyl alone, hand weeding and weedy check. Under N deficiency (N50%), Si500ppm increased plant height as compared to the control. No significant differences in SPAD values were detected amongst Si concentrations under each of the two tested N levels. Si can partially alleviate negative N deficiency effect on wheat yield, causing its increase to level obtained under normal N supply. Si has no effect on weed biomass when applied with fenoxaprop–p–ethyl either in sequence or in tank mixing. The most promising treatment for maximizing wheat grain yield was the application of 100 kg N ha–1 (N50%) x fenoxaprop–p–ethyl+Si250ppm in sequence", which also, in the same time, means reducing both cost of crop production and environment pollution.

Dissipation dynamics of fenoxaprop-p-ethyl (FPPE) and fenoxaprop acid (FPA) (metabolite) in rice field conditions was investigated for two consecutive seasons. FPPE dissipated rapidly in soil with average half life of 1.42-2.19 days. Dissipation followed first-order kinetics. The method was validated in terms of accuracy, linearity, specificity and precision. Linearity was in the range of 0.005-5 μ g mL-1 with limit of detection as 0.002 and 0.001 μ g mL-1 for fenoxaprop-p-ethyl and fenoxaprop acid, respectively. Quantitation limit in soil, grain, straw and husk were 0.005, 0.008, 0.01 and 0.01 μ g g-1 for fenoxaprop- p-ethyl, and 0.005, 0.01, 0.01 and 0.01 μ g g-1 for fenoxaprop acid, respectively. Recovery in soil, rice grains, straw and husk ranged from 81.60-93.40, 77.85-87.00, 75.20-84.40 and 76.00-87.20% for FPPE and 82.50-88.20, 76.25-83.00, 74.80-83.60 and 75.00-85.40% for FPA, respectively. Below detectable limit of residues of FPPE and metabolite were observed in soil, rice grain, husk and straw samples at harvest. FPPE and FPA were of short persistence under field conditions and residues were below European Union-Maximum Residue Limits in all matrices that would cause adverse effect on environment and human/animal health. [ABSTRACT FROM AUTHOR]

BACKGROUND The occurrence of herbicide-resistant weed biotypes is increasing and this report of an acetyl-CoA carboxylase (ACCase) inhibitor-resistant Digitaria sanguinalis L. Scop. from southwestern Ontario is another example. The identified weed escaped control in an onion and carrot rotation in which graminicides were used for several consecutive years. Our goal was to characterize the level and mechanism of resistance of the biotype. RESULTS The biotype was resistant to all five ACCase inhibitor herbicides tested. Gene-expression profiling was performed because none of the mutations known to confer resistance in the ACCase gene were detected. RNASeq and quantitative reverse-transcriptase PCR (qRT-PCR) results indicated that transcription of ACCase was 3.4-9.3 times higher in the resistant biotype than the susceptible biotype. ACCase gene copy number was determined by qPCR to be five to seven times higher in the resistant compared with the susceptible biotype. ACCase gene overexpression was directly related to the increase of the ACCase gene copy number. CONCLUSION Our results are consistent with the hypothesis that overexpression of the herbicide target gene ACCase confers resistance to the herbicide. This is the first reported case of target gene duplication conferring resistance to a herbicide other than glyphosate. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

No consórcio soja x forrageiras, estuda-se o momento de semeadura da cultura em relação a forrageira (concomitante ou defasada), para permitir vantagem competitiva às plantas da soja em relação à forrageira. Objetivou-se avaliar herbicidas e doses para aplicação na cultura da soja consorciada com Panicum maximum cv. Aruana, visando a supressão da forrageira. O experimento foi instalado em sistema de parcelões experimentais com subamostras, constituindo da semeadura defasada em 10 dias de capim-aruana nas entrelinhas da cultura da soja. Foram avaliados doses dos herbicidas glyphosate, fluazifop e fenoxaprop, no consórcio de soja com capim-aruana, aplicados 55 dias após a emergência (DAE) de ambas espécies (a emergência foi simultânea). Aos 69 DAE foram avaliados a massa fresca, massa seca, clorofila total, eficiência de controle do capim-aruana, perfilhos por planta e percentagem de perfilhos mortos das plantas de capim-aruana, bem como altura e conteúdo de água das plantas do capim e da soja, e a produtividade da cultura. Se a prioridade for a produtividade de grãos da cultura anual, a aplicação, em situação idêntica à avaliada neste estudo, do herbicida glyphosate a 1000 mL p.c. ha-1 é mais indicada, porém, com maior risco de redução da população da forrageira. Caso o objetivo do consórcio seja a formação de pastagem a aplicação, em situação idêntica à avaliada neste estudo, dos herbicidas fluazifop ou fenoxaprop a 500 mL p.c. ha-1 representa medida mais segura, permitindo garantir a população de plantas da forrageira ao custo de maior risco de interferência desta sobre a soja.

In the years 2003-2004 two experiments: laboratory and field, were carried out to detect the level of wild oat herbicide resistance. Weeds were collected from fields in south-eastern Poland, on the basis of survey conducted between farmers who have problems with wild oat herbicidal fighting. Two herbicides were tested: fenoxaprop- P-ethyl and diclofop methyl, both ACC-ase inhibitors. The laboratory test was established by modified Letouze et al. (1997) method. After 6-day growth on each herbicide water solution, the number of alive wild oat seedlings was assesed. In the field experiment plants in 3-5 leaf stage were sprayed with field dose of each herbicide. Two weeks after spraying the percentage of plants damage and in July the percentage of flowering plants were assesed. The wild oat plants that survive in laboratory test in ≥50% and plants that flowered in ≥50% in field conditions were recognized as resistant. On that basis wild oat resistace to fenoxaprop-P-ethyl and to diclofop methyl was stated on 17% and 28% fields from overall number of 18 fields, respectively.