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Musk mallow (Malva moschata) is a perennial European plant that grows in pastures and grass mixtures. M. moschata is a medicinal plant with a high content of polysaccharides, flavonoids, and other biologically active compounds. The sensitivity of the species to herbicides is, however, generally unknown. In our study, we investigated the effects of three herbicides with different active compounds: (1) Propaquizafop (PPQ), (2) Clopyralid (CPR), (3) Metamitron+Quinmerac (MMQ) on primary photosynthetic processes of M. moschata plants cultivated in two different temperatures (12 and 18 °C). Non-photochemical quenching (NPQ) of absorbed light energy by chlorophyll molecules and the parameters derived from fast chlorophyll fluorescence transient (OJIP) were evaluated before and then 1, 2, 5, 24, and 48 h after the herbicides application. Among the herbicides, only MMQ negatively affected the functioning of photosystem II (PSII). The effect, however, was reversible, and the plants reached pre-application values after 48 h. No herbicide-induced changes in NPQ were found over the time after the application. The majority of the OJIP-derived chlorophyll fluorescence parameters were found to be temperature-sensitive. The herbicides tested in our study may be ranked among those with only limited effects on primary photosynthetic processes in PSII. While the application of PPQ and CPR did not bring any negative effects on the functioning of PSII, MMQ application induced a decrease in the potential quantum yield of PSII (FV/FM) and activation of protective mechanisms, increased heat dissipation in particular. These changes, however, were fully alleviated 48 h after MMQ application. [ABSTRACT FROM AUTHOR]

Precision chemical thinning is the most common method of thinning apple fruitlets because it requires little time and is cost-effective. The aims of the current study were I.- to investigate the effect of the application of metamitron at different rates on 'Gala' apples; II.- to determine which fruit diameters were most sensitive to metamitron spray at several rates (between 180 and 500 ppm); and III- to identify the key environmental factors that explain Metamitron efficacy on a year-to-year basis. Eighteen trials were conducted over seven seasons, from 2015 to 2022 in 'Gala' apple orchards in Geneva (New York State). Metamitron was applied at different rates between 180 and 500 ppm, and the timing of the application was between petal fall (4.5 mm) and 18.5 mm fruit size. In each of the studies and years, the effect of meteorological parameters was evaluated. Our results suggest that a linear rate effect was observed in all trials, but that there were differences between the slopes of the regression every year because chemical thinning efficacy was variable year to year. The maximum metamitron efficacy was between 9.5 and 11 mm king fruit diameter; however, metamitron showed thinning efficacy at all phenological stages, from petal fall to 18.5 mm in 'Gala' apples. Our results suggest that the important meteorological factors affecting thinning efficacy were temperature and solar radiation on the day of application and for the next 6 days. The solar radiation after application of metamitron was the most important meteorological factor. Fruit drop caused by metamitron increased with low solar radiation. The minimum and maximum temperatures were also important factors in determining metamitron efficacy. A high minimum temperature (during the night) increased the fruit drop caused by metamitron and the maximum temperature during the day showed a negative correlation with the efficacy of metamitron. [ABSTRACT FROM AUTHOR]

Chemical thinning is currently the most utilized way of crop load regulation in apples to attain desired marketable fruit size. In intensive densely planted orchards, the lower part of crowns is more shaded and its response to chemical thinning can be strong. It often leads to very low fruit set in lower part of crowns and yield losses. Objective of our trial was to find out the response of the trees when thinning agents were applied on whole or only on an upper part of the crown. The trial took place in production orchard of variety ‘Golden Delicious’. Following thinning agents were used: benzyladenine, 1-naphthaleneacetic acid, and metamitron. Thinning and yield parameters were assessed. Fruit number of various fruit sizes was assessed separately for lower and higher part of the crown. The strongest thinning efficacy was recorded for application of metamitron on whole crown. This treatment caused the strongest thinning in lower part of crown and the strongest overall yield reduction. Application of metamitron only on upper part of crown avoid strong thinning in lower part of crown and ensured standard thinning in upper part of crown. Other treatments where only the upper part of the crowns were treated showed similar effects. Applied thinning agents thus showed spatially specific thinning action. Aimed application on upper part of crown proved to be useful and promising for practical use in intensive densely planted orchards.

In the period 2017–2019, field experiments were conducted at the Research and Education Center Gorzyń, unit Złotniki (52°486′ N; 16°819′ E), Poznan University of Life Sciences, at the Luvisols, under natural weather conditions, to evaluate the effect of multifunctional methylated seed oil (EXP 1, 2, and 3) and standard adjuvants (AtB and S) on the efficacy of mixtures phenmedipham + ethofumesate and metamitron applied in full (PEM 1) and reduced rates (PEM 2) in sugar beet. Field studies were carried out and three applications of herbicides were administrated subsequent to the emergence of weeds (BBCH 11–12). PEM applied at reduced rates with EXP was more effective than after AtB and S adjuvants. They enabled the attainment of high and consistent efficacy of herbicides (with EXP—96–97%, AtB—97%, S—95%, compared to PEM 1—93%, and PEM 2—82%), irrespective of varying weather conditions during, and subsequent to, their application. The sugar beet root yield from herbicide treatments after tested adjuvants was higher than from the untreated control and after application of reduced rates of herbicides without adjuvants. [ABSTRACT FROM AUTHOR]

Precision chemical thinning is the most common method of thinning apple fruitlets because it requires little time and is cost-effective. The aims of the current study were I.- to investigate the effect of the application of metamitron at different rates on ‘Gala’ apples; II.- to determine which fruit diameters were most sensitive to metamitron spray at several rates (between 180 and 500 ppm); and III- to identify the key environmental factors that explain Metamitron efficacy on a year-to-year basis. Eighteen trials were conducted over seven seasons, from 2015 to 2022 in ‘Gala’ apple orchards in Geneva (New York State). Metamitron was applied at different rates between 180 and 500 ppm, and the timing of the application was between petal fall (4.5 mm) and 18.5 mm fruit size. In each of the studies and years, the effect of meteorological parameters was evaluated. Our results suggest that a linear rate effect was observed in all trials, but that there were differences between the slopes of the regression every year because chemical thinning efficacy was variable year to year. The maximum metamitron efficacy was between 9.5 and 11 mm king fruit diameter; however, metamitron showed thinning efficacy at all phenological stages, from petal fall to 18.5 mm in ‘Gala’ apples. Our results suggest that the important meteorological factors affecting thinning efficacy were temperature and solar radiation on the day of application and for the next 6 days. The solar radiation after application of metamitron was the most important meteorological factor. Fruit drop caused by metamitron increased with low solar radiation. The minimum and maximum temperatures were also important factors in determining metamitron efficacy. A high minimum temperature (during the night) increased the fruit drop caused by metamitron and the maximum temperature during the day showed a negative correlation with the efficacy of metamitron.

In the period 2017–2019, field experiments were conducted at the Research and Education Center Gorzyń, unit Złotniki (52°486′ N; 16°819′ E), Poznan University of Life Sciences, at the Luvisols, under natural weather conditions, to evaluate the effect of multifunctional methylated seed oil (EXP 1, 2, and 3) and standard adjuvants (AtB and S) on the efficacy of mixtures phenmedipham + ethofumesate and metamitron applied in full (PEM 1) and reduced rates (PEM 2) in sugar beet. Field studies were carried out and three applications of herbicides were administrated subsequent to the emergence of weeds (BBCH 11–12). PEM applied at reduced rates with EXP was more effective than after AtB and S adjuvants. They enabled the attainment of high and consistent efficacy of herbicides (with EXP—96–97%, AtB—97%, S—95%, compared to PEM 1—93%, and PEM 2—82%), irrespective of varying weather conditions during, and subsequent to, their application. The sugar beet root yield from herbicide treatments after tested adjuvants was higher than from the untreated control and after application of reduced rates of herbicides without adjuvants.

Two new coordinated compounds enable them to function as an efficient detector for metamitron (MMT). It boasts a limit of detection of 2.72 ppm and exhibits quenching constant (K SV) values of 0.09, making it an effective luminescent sensor for detecting MMT. [Display omitted] Developing highly stable materials for harmful compound detection in a water environment is of much importance and challenge. we report two cadmium based fluorescent coordination compounds with formula [Cd(HL)(phen)(H 2 O) 3 ] (1) and [Cd(HL)(2,2′-bipy)(H 2 O) 2 ] (2) where H 3 L = 4-(N,N'-bis(4-carbonylbenzyl)amino)-3-methylbenzenesulfonic acid, phen = 1,10-phenanthroline monohydrate and 2, 2′-bipy = 2, 2′-bipyridine. Details structural studies showed that compounds 1 and 2 are mononuclear and binuclear discrete compounds, respectively. Its excellent luminescence stability in aqueous solutions, coupled with outstanding thermal and chemical stabilities, enables it to function as an efficient detector for metamitron (MMT). It boasts a limit of detection of 2.72 ppm and exhibits quenching constant (K SV) values of 0.09, making it an effective luminescent sensor for detecting MMT. The luminescence quenching of the compound 1 by MMT was attributed to competing absorption and photoelectron energy transfer mechanisms. [ABSTRACT FROM AUTHOR]

Copyright of Progress in Plant Protection is the property of Institute of Plant Protection 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.)

In einem Halbfreiland-Gefäßversuch an der Fachhochschule Südwestfalen in Soest wurde 2018 und 2019 die Wirkung verschiedener Zuckerrübenherbizide auf verschiedene Herkünfte von weißem Gänsefuß (Chenopodium album, CHEAL) untersucht, die über bekannte Resistenzen gegen Metamitron aufgrund nachgewiesener Punktmutationen verfügen. In praxisüblichen Aufwandmengen wurden die Herbizide Metamitron, Ethofumesat und auch Kombinationen aus Ethofumesat + Phenmedipham + Desmedipham, sowie aus Metamitron + Quinmerac + Ethofumesat + Phenmedipham + Desmedipham jeweils einmalig im Keimblattstadium oder im 1-2-Blattstadium des Weißen Gänsefußes eingesetzt. Untersucht wurden eine sensitive Herkunft (Bingen) sowie drei Herkünfte mit unterschiedlichen Punktmutationen (Bröckel, Kortessem, Warpke). Die fehlende Wirksamkeit beim Einzelwirkstoff Metamitron wurde bei allen Mutanten erwartungsgemäß sehr deutlich. In 2018 erzielten Wirkstoffkombinationen aus Phenmedipham + Desmedipham + Ethofumesat deutliche Wirkungsverstärkungen, wobei erst durch die auch in der Praxis angewandte Kombination mit zusätzlich Metamitron + Quinmerac bei der Behandlung im Laubblattstadium die erwünschten hohen Wirkungsgrade erreicht wurden. In 2019 wurden durch die Anwendung der Kombination mit fünf Wirkstoffen im Keimblattstadium nur bei der sensitiven Herkunft (Bingen) hohe Wirkungsgrade (WG) erzielt (95 % WG). Die Laubblattbehandlung erzielte dagegen bei der Herkunft aus Bingen (sensitiv) 85 % WG und bei der Herkunft Bröckel („Leu218Val“) 86 % WG.

Die Exposition von Pflanzen gegenüber moderatem Umweltstress ist eine wichtige Quelle für evolutionäre Veränderungen aufgrund von genetischen und phänotypischen Reaktionen. Da Herbizid-Hormesis als die wachstumsstimulierende Wirkung niedriger Herbizid-Dosierungen ebenfalls einen moderaten Stress für exponierte Pflanzen darstellt, sind generationsübergreifende Auswirkungen denkbar. Insbesondere bei herbizidresistenten Unkräutern, die bei praxisüblichen Aufwandmengen in ihrer reproduktiven Fitness hormetisch gefördert werden, könnte dieser Aspekt zur Evolution von Herbizidresistenz beitragen. Im Gegensatz zu Insekten und Bakterien liegen Erkenntnisse eines solchen generationsübergreifenden Einflusses von Hormesis bei Pflanzen bisher nicht vor. In der vorliegenden Studie wurden PSII Target-Site resistente Chenopodium album Pflanzen mit verschiedenen Dosierungen des PSII-Inhibitors Metamitron behandelt und bis zur Samenreife kultiviert (Parentalgeneration P). Die resultierenden F1-Generationen ausgewählter P-Vorbehandlungen wurden erneut in einem Dosis-Wirkungsversuch mit Metamitron behandelt. Dabei zeigte sich ein signifikanter Einfluss der P-Vorbehandlung auf die Reaktion der F1-Nachkommen. Die Sensitivität von F1-Pflanzen bei P-Vorbehandlung mit ultra-niedrigen und inhibierenden Dosierungen war teilweise höher als bei F1-Pflanzen unbehandelter P-Pflanzen. Eine P-Vorbehandlung mit hormetischen Dosierungen führte dagegen zu einer signifikant geringeren Sensitivität bei F1- Pflanzen. Die Ergebnisse deuten darauf hin, dass Herbizid-Hormesis generationsübergreifende Reaktionen hinsichtlich Herbizidsensitivität induziert, deren Ausprägung jedoch in Abhängigkeit der Dosierung der P-Vorbehandlung variiert. Grundsätzlich könnte dies evolutionäre Veränderungen bei Unkräutern fördern.

Peach tree thinning is essential for harvesting quality fruits and maintaining balanced fruit production for several years. Manual thinning of peach trees requires a large workforce, thereby increasing the production costs. Chemical thinning may be an alternative solution, but its efficiency depends on the dose of the chemical and plant species. This study aimed to evaluate the effect of different concentrations of metamitron on the chemical thinning of peach trees in southern Brazil. The experiment was carried out in a commercial orchard of peach cultivar 'Sensação' in Morro Redondo, Rio Grande do Sul (RS) state, Brazil. Different metamitron concentrations100 mg L-1, 200 mg L-1, 300 mg L-1, and 400 mg L-1were applied, and manual thinning was carried out 40 days after full bloom (DAFB) and to the treatment where the plants had no thinning. Fruit abscission, effective fructification, total number of plants per plant, production per plant, mean mass, and fruit diameter were evaluated. Applications of 300 and 400 mg L-1 metamitron 40 DAFB promoted high fruit abscission, in addition to decreasing the number of fruits and production. In contrast, applications of 100 and 200 mg L-1 of metamitron 40 DAFB was as efficient in thinning as manual thinning practice with respect to fruit production and fruit mass and its diameter. [ABSTRACT FROM AUTHOR]

Abstract The objective of this work was to evaluate the effect of chemical thinning with metamitron on fruit of the Maciel and Sensação peach (Prunus persica) tree cultivars, as well as to identify its relation to the carbohydrate content in their branches. The experimental design was randomized complete blocks, and the treatments were trees with no thinning, manual fruit thinning, and chemical thinning with 200 mg L-1 metamitron applied at 20, 40, and 60 days after full blooming. The evaluated variables were: abscission percentage, yield per plant, number of fruit, presence of lignin in fruit, and carbohydrate content in the branches. The carbohydrate content was evaluated in trees with and without chemical thinning seven days after the application of the product. The use of metamitron promotes fruit thinning in the ‘Maciel’ and ‘Sensação’ peach trees, with a decrease in the carbohydrate content in their branches. Metamitron application 20 and 40 days after full blooming favors fruit abscission in both studied cultivars.

Apple blossom or fruitlet thinning is currently the basic care treatment in the production of apples for dessert fruit. It determines the regularity, levels and quality of yields. The fastest method of fruitlet thinning is chemical thinning performed by means of registered purpose-developed preparations. The response of apple trees to chemical thinning is largely dependent on the genetic traits and on the physiological status of the tree, and on the climatic conditions in a given season. Braeburn, and especially its coloured mutations, e.g. Braeburn Mariri Red, is a prospective cultivar for cultivation in Poland, as it stores well without loss of firmness. In addition it is characterised by more sour flesh taste compared to popular apples of cultivars ‘Golden Delicious’, ‘Gala’ or ‘Jonagold’, due to which it can be in demand in periods when apples of cv. ‘Antonówka’ are no longer available. The study analysed the effect of the Polish-registered preparations Brevis 150 SG and MaxCel on the level and quality of yield of cultivar ‘Braeburn Mariri Red’. Each of the methods of thinning caused a significant improvement of fruit size relative to the control. Only the application of MaxCel at the lower dose of 5l ha–1 proved to be completely ineffective in both seasons of the experiment due to the lack of any improvement in yield structure, in fruit weight, and also in fruit diameter and height. The application of Brevis at 1.1 kg ha–1 and of MaxCel at 7.5 l ha–1 produced similar effects on the level and structure of yield, but apples from trees treated with Brevis at 1.1 kg ha–1 were characterised by notably higher fresh firmness. The best effects of thinning were noted after the combined application of the preparations MaxCel/Brevis, as the yield was notably lower than in the control treatment, and the fruits were characterised by the highest values of the analysed quality parameters, i.e. fruit weight, diameter, height, and content of extract and dry matter.

[Display omitted] • A new method for the synthesis of TiO 2 -MIL-53(Al) nano-composite. • Rapid and complete photocatalytic degradation of an herbicide using the composite. • Complete degradation of a mixture of herbicide, dye and phenol using the synthesized composite. • Superior reusability of the composite material. In the present work, we report a new approach for the synthesis of TiO 2 -MIL-53(Al) (MIL: Matériaux de l′Institut Lavoisier) nano-composite. The integration of microwave synthesized metal organic framework (MOF) with combustion synthesized metal oxide is reported for the first time. The synthesized materials were characterized using an X-ray diffractometer, Fourier transform infrared spectrometer, scanning electron microscope, energy dispersive X-ray spectroscope, energy dispersive X-ray fluorescence, porosimeter, and UV–visible diffuse reflectance spectroscope. The diffraction pattern of the composite indicated the presence of TiO 2 as well as MIL-53(Al). Furthermore, the presence of anatase–rutile mixed phase of TiO 2 in the synthesized material was observed. The Fourier transform infrared spectrum was in support of XRD observations. A significantly low surface area and porosity of the composite material, compared to its parent components, was observed. The surface micrograph image of the composite depicted its nano-sheet type morphology. The energy dispersive X-ray analysis confirmed the presence of Ti, Al, C and O in the composite material. The composite material exhibited a narrow band-gap compared to the pristine MIL and TiO 2. As an application, the photocatalytic activity of synthesized material was determined by the degradation of metamitron. The application part is also one of the novelties of the present work. The effect of catalyst loading, initial concentration of metamitron and presence of inorganic ions on the photocatalytic degradation was investigated. The reusability of the composite material was evaluated. A plausible mechanism of photocatalytic degradation is proposed based on radical scavenging experiments. To the best of our knowledge, to date, there is no study on the application of TiO 2 -MOF composite for the photocatalytic degradation of herbicide. Further, the synthesized material was successfully used for the photocatalytic degradation of a complex mixture of pollutants comprising metamitron, methylene blue, rhodamine B and 2, 4-dichlorophenol. This is a first of its kind study to demonstrate the application of TiO 2 -MOF composite for photocatalytic degradation of a highly complex mixed pollutant. [ABSTRACT FROM AUTHOR]

In this study, photocatalytic degradation of a herbicide, metamitron, was carried out using combustion synthesized nano-TiO2. The synthesized catalyst was characterized using X-ray diffraction, porosimetry and UV-diffuse reflectance spectroscopy. The combustion synthesized catalyst showed lower crystallite size, better surface area and narrower band-gap compared to the commercial TiO2. The effect of catalyst loading, initial concentration of metamitron, pH and presence of inorganic ions on the extent of degradation was studied. The pseudo first order rate constant of metamitron degradation using combustion synthesized TiO2 was 1.5–2.5 times higher than that using commercial TiO2 at different initial concentrations of metamitron. The effect of another component, Rhodamine-B dye, on the degradation of metamitron was also probed in this study. The rate of degradation of both metamitron and Rhodamine B were high when the combined system was treated. The degradation by-products were tracked using liquid chromatograph/mass spectrometer, and a possible degradation pathway is proposed.

The work aimed to clarify the effects of metamitron as the fruit thinning agent on the apple fruit setting rate as well as the mineral nutrition, carbohydrates, and hormones of lateral fruitlets, thus providing a reference for applying chemical thinning technology of apples. Thirty 9-year-old apple trees (Tianhong 2/SH38/Malus micromalus) were used as test materials, and 300-ppm metamitron solution was sprayed 2 times when the diameter of the biggest lateral fruits were around 6 mm. Spraying water was used as the control. The setting rate of inflorescence and flower were investigated after physiological fruit drop. The mineral nutrition, carbohydrate, soluble protein, and hormone content of lateral fruits were measured after spraying 7, 9, 11, 17, and 29 d. The total nitrogen, phosphorus, and potassium were determined by semi-micro distillation, Mo-Sb-Vc colorimetry, and flame photometer, respectively. Glucose, fructose, sorbitol, sucrose, and hormone contents were determined by HPLC, while the soluble protein content was determined by Coomassie brilliant blue staining. The results showed that the fruit setting rate of inflorescence and flowers decreased by 17.95 and 27.63% compared with the control, respectively. The proportion of inflorescence with single fruit increased by 5.28 times in the treatment, while that of sitting three fruits and more decreased significantly, which was 47.91% of the control. The results of fruit setting rate and fruit setting ratio showed that metamitron could significantly reduce the fruit setting rate, and the single fruit rate was high, with the setting fruits distributed evenly. The total nitrogen content was higher than that of the control at all stages, and the difference between the control and the treatment was significant except 7 and 9 d. The total phosphorus and potassium contents of almost all treatments were significantly higher than those of the control. The total phosphorus contents of 11 and 29 d after spraying was 2.05 and 1.67 times of the control, and the total potassium content was 1.93 and 1.51 times of the control, respectively. The results of mineral nutrition showed that the fruit thinning effect of metamitron was not caused by the deficiency of inorganic nutrients. The content of the soluble protein decreased significantly compared with the control, and the content of each treatment period was 71.42, 72.37, 69.68, 64.20, and 86.02% of the control, respectively. The starch content of metamitron treatment was significantly higher than that of the control, with an increase of 5.57%-37.20%, yet the content of sucrose, glucose, fructose, and sorbitol decreased with different degrees. Therefore, the soluble carbohydrate content decreased significantly to 9.55%-52.57%. Soluble carbohydrates are the direct nutrients for the development of young fruits, so fruit thinning of metamitron may be caused by insufficient supply of soluble carbohydrates. The abscisic acid content generally increased after the treatment, and the ABA content in each period was 1.37-3.11 times that of the control. The ratio of (Z+GA3+IAA)/ABA decreased significantly, which could cause falling off of young fruits. As a result, metamitron has a good fruit thinning effect on apples, related to the decreased soluble protein content, an insufficient supply of soluble carbohydrate, increased ABA content, and decreased (Z+GA3+IAA)/ABA ratio. [ABSTRACT FROM AUTHOR]

Metamitron is an apple (Malus domestica Borkh.) fruit thinner that acts by reducing the photosynthetic capacity of trees. Relative humidity may influence thinning efficacy; however, the broadness of this effect is not yet fully understood. Trials were set in Sint-Truiden (Belgium) in 2018 and Lleida and Girona (Spain) in 2019, using 4-year-old cvs. Braeburn and Elstar trees in Belgium, and 16-year-old cv. Golden Reinders trees in Spain. Four treatments were implemented at the stage of 12-14 mm fruit diameter: (a) CTR--control, trees under natural environmental conditions; (b) HH--high humidity, trees submitted to artificially increased air relative humidity applied for 3 h prior to the beginning of the experiment; (c) MET--trees sprayed with 247.5 mg/L metamitron; (d) MET + HH--trees submitted to the combination of increased humidity (HH) and metamitron (MET) application. In Belgium, metamitron absorption by leaves was greater than in Spain. This might be related to morphological characteristics of the leaves which developed under greater natural relative humidity levels in Belgium than in Spain. Compared to MET alone, 'Braeburn' and 'Elstar' demonstrated significantly greater metamitron absorption, 59% and 84%, respectively, under MET + HH, accompanied by declines in leaf net photosynthesis (10% and 32%, respectively) and sucrose (31% and 26%, respectively). At harvest, MET + HH treatment reduced yield by 24% and 32% in 'Braeburn' and 'Elstar', respectively, when compared with MET alone. A large reduction (considered over thinning) in the yield of 'Elstar' occurred. In contrast, metamitron absorption by 'Golden Reinders' using MET alone was similar to MET + HH; however, there was a slight foliar sugar reduction in the latter treatment. In addition, both treatments enhanced shoot growth and increased fruit abscission with similar improvements in fruit weight and size. In this study, high relative humidity enhanced fruit thinning efficacy under certain circumstances, such as age or genetic predisposal, which left the tree more susceptible to a negative carbohydrate balance. For instance, 'Braeburn' and 'Elstar' were easier to thin when compared to 'Golden Reinders'. In addition, this study raises a question that requires further research regarding the impact of HH before and after spraying as well as its effect in combination with higher temperatures. [ABSTRACT FROM AUTHOR]

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Abstract According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the pesticide active substance metamitron. To assess the occurrence of metamitron residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/EEC as well as the import tolerances and European authorisations reported by Member States (including the supporting residues data). Based on the assessment of the available data, MRL proposals were derived and a consumer risk assessment was carried out. Although no apparent risk to consumers was identified, some information required by the regulatory framework was missing. Hence, the consumer risk assessment is considered indicative only and some MRL proposals derived by EFSA still require further consideration by risk managers.

Abstract: The objective of this work was to evaluate the effect of thinning with metamitron on the fruit yield and quality of 'BRS Kampai' peach (Prunus persica) trees. The experiment was carried out in the municipality of Eldorado do Sul, in the state of Rio Grande do Sul, Brazil, in the 2016 and 2017 crop years. Treatments consisted of the application of 100, 200, 300, and 400 mg L-1 metamitron and of hand thinning 40 days after full bloom, besides control plants. Fruit abscission, effective fructification, number of fruits, and fruit yield per plant were evaluated. Regarding fruit quality, fresh fruit biomass, epidermis color, pulp firmness, soluble solids, total phenolic compounds, and antioxidant activity were assessed; fruits were also classified into diameter classes. For fruit abscission, the effect of the application of 100 mg L-1 metamitron is similar to that of hand thinning. Fruit yield and mean mass in all treatments with metamitron are similar to those obtained by hand thinning. The application of metamitron does not affect the fruit quality of peach trees. Chemical thinning with metamitron may be an alternative to hand thinning in peach trees used for the production of fruits for fresh consumption.

The aim of this study was to evaluate the thinning efficacy of metamitron applied either alone (single or double application) or in combination with 6-benzyladenine (BA) or naphthalene acetic acid (NAA) in young 'Gala' and 'Golden Delicious' apple trees. The experiment was carried out during the first three crop seasons, 2014, 2015, and 2016, at the commercial orchard located on the mountain Fruska Gora, Serbia. Application of chemical thinners was carried out at two fruit diameter stages (6-9 and 12-15 mm). The number of fruit and yield per tree, fruit size distribution, parameters of fruit ripeness, and return bloom were assessed. Single metamitron treatments were effective when the weather conditions were favourable on the day of application and 3 days after (minimum night temperature >10 °C, maximum daily temperature >20 °C) regardless of fruit diameter stages. A reduction in fruit number per tree was followed by an increase in mean fruit weight. Double metamitron application at lower concentration caused relatively stable thinning activity during the whole experimental period in both cultivars tested. Metamitron combined with either BA or NAA at standard rates significantly reduced the negative influence of low temperature on metamitron thinning activity in the first experimental year. These treatments slightly influenced overthinning in 'Gala' trees if applied when the air temperature was too high (minimum night temperature >15 °C, maximum daily temperature >25 °C). Repeated metamitron treatment and treatments in which metamitron was combined with BA and NAA resulted in an increase in fruit size and share of large fruit in the total yield during the whole experimental period in both cultivars tested. A reduction in fruit number per tree affected by these treatments was followed by increasing flowering intensity in the subsequent year, with the exception of double metamitron application to 'Golden Delicious' trees in the last experimental year. Fruit maturity parameters were slightly different under the influence of metamitron treatments. [ABSTRACT FROM AUTHOR]

According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the pesticide active substance metamitron. To assess the occurrence of metamitron residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/EEC as well as the import tolerances and European authorisations reported by Member States (including the supporting residues data). Based on the assessment of the available data, MRL proposals were derived and a consumer risk assessment was carried out. Although no apparent risk to consumers was identified, some information required by the regulatory framework was missing. Hence, the consumer risk assessment is considered indicative only and some MRL proposals derived by EFSA still require further consideration by risk managers [ABSTRACT FROM AUTHOR]

In the present study, the electrocatalytic degradation of triazine herbicide metamitron using Ti/PbO2-CeO2 composite anode was studied in detail. The effects of the current density, initial metamitron concentration, supporting electrolyte concentration, and initial pH value were investigated and optimized. The results revealed that an electrocatalytic approach possessed a high capability of metamitron removal in aqueous solution. After 120 min, the removal ratio of metamitron could reach 99.0% in 0.2 mol L−1 Na2SO4 solution containing 45 mg L−1 metamitron with the current density at 90 mA cm−2 and pH value at 5.0. The reaction followed the pseudo-first-order kinetics model. HPLC and HPLC-MS were employed to analyze the degradation by-products in the metamitron oxidization process, and the degradation pathway was also proposed, which was divided into two sub-routes according to the different initial attacking positions on metamitron by hydroxyl radicals. Therefore, the electrocatalytic approach was considered as a very promising technology in practical application for herbicide wastewater treatment. [ABSTRACT FROM AUTHOR]

Metamitron (Meta), an herbicide, and fenhexamid (Fen), a fungicide, are authorized by the European Union to be used in agriculture. This article reports theoretical calculations about Meta and Fen in interaction with a clay surface: a Ca‐montmorillonite (Mont). Conformational searches have been performed thanks to Car–Parrinello molecular dynamics simulations from which geometries have been extracted. Interaction and adsorption energies have been calculated for isomers of Meta or Fen in interaction with Mont to understand the relative stability of various kinds of complexation. Substantial adsorption energies are comparable for Meta and Fen: around −40 kcal/mol. For Fen‐Mont, the CO monodentate family is surprisingly the lowest in energy. Moreover, the 10 lowest‐energy isomers involve complexation on Fen carbonyl oxygens. The Meta‐Mont lowest‐energy family, N‐N, does not involve π delocalization breaking within Meta. At the same time, the stronger the interaction energy is, the larger the structural modifications within Mont are, particularly concerning the interacting cation distance to the surface. The non‐negligible charge transfer and the magnitude of the adsorption energy speak in favor of the chemisorption of the pesticide on the surface. © 2019 Wiley Periodicals, Inc. Adsorption of two pesticides, metamitron and fenhexamid, on a model for soil mineral matter (a montmorillonite surface) was studied by means of density functional molecular dynamics. For both pesticides, the non‐negligible charge transfer and the magnitude of the adsorption energy (Eads) suggested that the pollutant was chemisorbed on the clay surface. In both cases, the orientation of the pesticide toward the surface implied a large dispersion contribution. [ABSTRACT FROM AUTHOR]

BACKGROUND: Herbicide hormesis may play a role in the evolution of weed resistance by increasing resistance selection. A standard herbicide rate may be subtoxic to resistant plants and make them more fit than untreated plants. If this increase in fitness is ultimately expressed in reproductive traits, resistance genes can accumulate more rapidly and exacerbate resistance evolution by magnifying the selection differential between resistant and sensitive plants. The hypothesis of hormetically enhanced reproductive fitness was studied for a photosystem II (PSII) target‐site resistant (TSR) biotype of Chenopodium album exposed to the triazinone metamitron in comparison with its wild‐type. RESULTS: Both biotypes showed an initial hormetic growth increase at different doses leading to fitness enhancements of between 19% and 61% above untreated plants. However, hormetic effects only resulted in higher fitness at maturity in resistant plants with a maximum stimulation in seed yield of 45% above untreated plants. Applying realistic metamitron rates, reproductive fitness of resistant plants was increased by 15–32%. CONCLUSIONS: Agronomically relevant doses of metamitron induced considerable hormesis in a PSII‐TSR C. album genotype leading to enhanced relative fitness through reproductive maturity. This increase in relative fitness suggests an impact on resistance selection and can compensate for the oft‐reported fitness costs of the mutation studied. Field rates of herbicides can, thus, not only select for resistant plants, but also enhance their reproductive fitness. The finding that herbicide hormesis can be eco‐evolutionary important may have important implications for understanding the evolution of herbicide resistance in weeds. © 2018 Society of Chemical Industry This article presents evidence that a regular herbicide application can select resistant weeds and hormetically boost fitness of selected plants. This increase in the relative fitness of resistant plants by herbicide hormesis can impact potential rates of evolution and compensate for fitness costs of the mutation being studied. [ABSTRACT FROM AUTHOR]

In this paper, a chronopotentiometric method for the determination of herbicide metamitron (MTM) using a glassy carbon electrode (GCE) and a thin film mercury electrode (TFME) as working electrodes is presented. MTM provided a well-defined reductive peak in the Britton-Robinson buffer on both working electrodes. Instrumental and chemical factors such as pH of the buffer, initial potential and reduction current influencing MTM chronopotentiometric response were optimised with the Box-Behnken experimental design. Under the optimal combination of factors, the analytical signal was linear in the MTM concentration range of 0.8-30 mg/L, with a detection limit of 68.53 μg/L using a TFME, and in the concentration range of 1-30 mg/L, with a detection limit of 92.91 μg/L using a GCE. The precision of the method was estimated as a function of repeatability and reproducibility, with the value of relative standard deviation lower than 2.6%. The applicability of the method was verified by direct analysis of MTM in spiked water samples and commercial pesticide formulations. The obtained results were in good agreement with those obtained using liquid chromatography/tandem mass spectrometry (LC-MS/MS) method, or with those labelled by the manufacturer. By using chronopotentiometry, neither extraction nor preconcentration procedures are necessary, thus making this method simple, cost-effective and more feasible for analytical routine analysis. [ABSTRACT FROM AUTHOR]

In the last decade, the prevalence of Atriplex patula as a weed in the Belgian sugar beet area has increased. Possible reasons for its expansion in sugar beet fields, besides a poor implementation of the low-dose phenmedipham/ activator/soil-acting herbicide (FAR) system, might be low sensitivity or evolved resistance to one or more herbicides used in sugar beet. Dose-response pot bioassays were conducted in the glasshouse to evaluate the effectiveness of five foliar-applied sugar beet herbicides (metamitron, phenmedipham, desmedipham, ethofumesate and triallate) and three preplant- incorporated herbicides (metamitron, lenacil, dimethenamid-P) for controlling five Belgian A. patula populations. Local metamitron-susceptible and metamitron- resistant populations of Chenopodium album were used as reference populations. Effective dosages and resistance indices were calculated. DNA sequence analysis of the photosystem II psbA gene was performed on putative resistant A. patula populations. Overall, A. patula exhibited large intraspecific variation in herbicide sensitivity. In general, A. patula populations were less susceptible to phenmedipham, desmedipham, ethofumesate and triallate relative to C. album populations. Two A. patula populations bear the leucine-218 to valine mutation on the chloroplast psbA gene conferring low level to high level crossresistance to the photosystem II inhibitors phenmedipham, desmedipham, metamitron and lenacil. In order to avoid insufficient A. patula control and further spread, seedlings should preferentially be treated with FAR mixtures containing higher-than-standard doses of metamitron and phenmedipham/desmedipham and no later than the cotyledon stage. [ABSTRACT FROM AUTHOR]

A field experiment on the application of the herbicide Lawina 700 SC (the active ingredient metamitron – under different application regimes) was carried out in Priluki near Minsk, Belarus, over the period 2011–2013. It was proved that herbicide application in lacy phacelia crops is not always justified. With intensive growth, the crop plant itself competes with weeds and the application of herbicides is not advisable. It was only in one out of the three years that the weeds delayed and disturbed the growth of phacelia, their harmfulness proved to be significant, and herbicide application had a measurable effect. It turned out that the difference in biological and economic effectiveness between a single and double application of metamitron was insignificant and the phytotoxic effect was not found to increase. The most appropriate herbicide application regime that protected lacy phacelia against annual dicotyledonous weeds was a single application of metamitron (1.4 l∙ha-¹) at the 1–2 true leaf pair stage. The study also showed that the herbicide metamitron, applied both before emergence and after emergence of phacelia, may exhibit phytotoxic activity against the cultured crop, slowing down plant growth and causing a decrease in the seed yield. The effectiveness of metamitron application before emergence – both at the rate of 1.4 l∙ha-¹ and at a higher rate (2.1 l∙ha-¹) – proved to be very unstable, in particular in the aspect of direct phytotoxicity of the herbicide on the crop plant, but also in the aspect of periodic accumulation of the biologically active substance in the soil.

The effect of different blossom thinners ammonium thiosulfate (ATS) (1%, 2%), Armothin (1.5%), Tergitol-TMN-6 (0.5%, 1%), applied on peach cv. Redhaven at 50-60% full bloom was evaluated in thinning experiments in south-west Slovenia. The photosynthesis inhibitor metamitron (0.05%) applied at 8 mm fruit diameter was evaluated as fruitlet thinner as well. Application of 2% ATS resulted in excessive thinning. The thinning effect of 1% ATS was also too strong in two out of three thinning experiments. The use of 0.05% metamitron did not cause any thinning effect on peach trees and gave similar results as the non-treated control. The effective fruit set reduction and increase of average fruit weight was achieved with 0.5% and 1% Tergitol application. In three-year experiment both Tergitol applications reduced fruit set toward hand thinned level, but the share of fruit from bigger size class was only once enhanced to the level of hand thinned trees. No sign of phytotoxicity was noticed on fruits in all thinner application treatments.

The dependence of the quantum yield of metamitron on oxygen concentration in the range c O 2 = (0.005–12.6)· 10 −4 M in aqueous solution was investigated with a polychromatic Xe-light source in the wavelength region 270–376 nm. The quantum yield of Φ = 0.022 ± 0.002 mol mol −1 at T = (293 ± 3) K and c O 2 = 2.8 · 10 − 4 M is independent from metamitron concentration in the range of c M = 8 ·10 −8 − 1.8 · 10 −4 M. A weak temperature dependence of the photolysis of metamitron at constant oxygen concentration was found with an activation energy of E A = (3 ± 1) kJ mol −1 . The yield ( ν = 0.91) of the main product desamino-metamitron does not depend on start concentration of metamitron, oxygen concentration or temperature (in the range of T = 281.5–327 K). Oxygen is necessary in the photolysis of metamitron. Quantum yields for the photoreaction of metamitron increase from practically zero at low oxygen concentrations (Φ = 0.002 mol mol −1 at c O 2 < 3 · 10 − 6 M) to a maximum of Φ max = 0.042 mol mol −1 at c O 2 = 5.1 · 10 − 5 M and declines with increasing oxygen concentration to a value of Φ = 0.006 mol mol −1 in oxygen saturated solutions. Two reaction sequences with a reaction from the triplet state T 1 and from a recently proposed transient triplet state T 1 ′ were used to explain the oxygen-dependent rate constants of metamitron. Both sequences explain the oxygen dependence equally well and it was not possible to distinguish between both mechanisms. Aqueous solutions of metamitron are recommended as a promising actinometric system, especially suitable for measurements in sunlight. [ABSTRACT FROM AUTHOR]

The excessive use of herbicides can cause ground water contamination and is also a potential threat to the nearby aquatic ecosystem. In this work, we report photocatalytic degradation of metamitron using CeO2and Fe/CeO2. The effect of catalyst loading on the degradation was studied. A significant effect on photocatalytic degradation was observed with bare-CeO2. On the other hand, photolysis and Fe/CeO2displayed similar effect on the degradation. Thus, it was concluded that lowering the band gap, by doping, is not always favorable for enhancing the photocatalytic degradation. [ABSTRACT FROM AUTHOR]

Metamitron (Meta), 4-amino-3-methyl-6-phenyl-1,2,4-triazin-5-one, and fenhexamid (Fen), N-(2,3-dichloro-4-hydroxyphenyl)-1-methylcyclohexanecarboxamide, are active substances of herbicide and fungicide products, respectively, employed in agriculture. When these molecules are spread on crops, an important amount reaches the soil and diffuse through water to deep layers of the soil structure and thus to groundwater tables. To get some insight into the interaction of pesticides with soil, in particular clay surfaces, we have run theoretical calculations. This paper presents preliminary results of this wide and challenging work. Metamitron, fenhexamid and their complexes with one or two Ca 2+ and Na + , which are among the most abundant cations into soils, are under investigation. Conformational searches have been performed thanks to Car-Parrinello molecular dynamics (CPMD) simulations from which geometries as well as relative, complexation and interaction energies have been extracted. Thermodynamical complexation values have been calculated for complexes of Meta or Fen with one or two cation(s) in order to understand the complex stability. We found that complexation free energies are comparable for Meta and Fen: around −32 kcal/mol with one sodium cation, ≈−130 kcal/mol with one Ca 2+ , and −7 kcal/mol with two Na + . With two Ca 2+ , complexation free energy is four times larger in absolute value for Fen (−40 kcal/mol) than for Meta due to longer inter-cation distances in Fen-(Ca 2+ ) 2 complexes. The larger values obtained with Ca 2+ in the gas phase suggest a strong adsorption of Meta and Fen with Ca 2+ -montmorillonite clay surfaces. [ABSTRACT FROM AUTHOR]

An all-solid-state impedimetric microsensor based on impedimetric measurements for detecting the herbicide metamitron (MM) is reported in the present work. For this purpose, a novel metamitron ionophore has been prepared. It was based on the isolation of the metamitron monoprotonated form coupled to the metallocarborane anion, cobalt bis (dicarbollide), ([3,3′-Co(1,2-closo-C2B9H11)2]−) as an ion-pair complex of the type [3,3′-Co(1,2-closo-C2B9H11)2]−[C10H11ON4]+. Once the ion-pair complex was synthetized, it was incorporated to a PVC-type membrane including o-Nitrophenyloctylether (o-NPOE) as plasticizer. The membrane was then drop-cast on top of polypyrrole-modified gold working microelectrodes. A quick response of 30 s has been provided by the microsensor in the range of metamitron concentrations between 10−8 M and 10−4 M with a limit of detection of 10−8 M. Furthermore, it was highly selective toward metamitron, when compared to some possible interfering compounds as imazapic and carbetamide.

[Display omitted] • Metribuzin (MTZ) and metamitron (MTT) are refractory herbicides towards ozone. • Tourmaline achieved excellent catalytic ozonation activity toward MTZ and MTT. • Rate constants k O3 , MTZ ; k O3 , MTT , and k OH , MTT have been determined. • Possible pathways for the degradation of MTZ and MTT in ozonation were proposed. The reaction kinetics and degradation mechanisms of the herbicides metribuzin (MTZ) and metamitron (MTT) were evaluated during conventional and tourmaline-catalyzed ozonation processes. The tourmaline catalyst was characterized by X-ray diffraction, field emission-scanning electron microscopy, Brunauer-Emmett-Teller surface analysis and Fourier transform infrared spectroscopy. The reactivities of these two herbicides with ozone (O 3) are low due to their refractory characteristics, so catalytic ozonation is an ideal way to effectively degrade them. The effects of catalyst dosage, pH, temperature and ozone concentration on catalytic degradation of MTZ and MTT were investigated. Based on the results from quenching experiments and calculation of second-order rate constants (k O3, MTZ (4.82 ± 0.42 M−1 s−1), k O3, MTT (13.35 ± 0.62 M−1 s−1) and k •OH, MTT ((6.90 ± 0.51) × 109 M−1 s−1)), it was found that oxidation of the pollutants was mediated by decomposition of O 3 to produce •OH. Twelve MTZ degradation products and five MTT degradation products were identified by gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry, and the reaction mechanisms were analyzed. In addition, the potential toxicities of the derivatives formed during catalytic ozonation were examined. The degradation products of the two pollutants exhibited different toxicity profiles. The environmental-friendliness and efficient catalytic properties of tourmaline suggest that it has great potential as a heterogenous and green catalyst. [ABSTRACT FROM AUTHOR]

Metamitron and its main metabolite desamino-metamitron are frequently detected in surface waters. To date, there are no studies targeting metamitron degradation in water-sediment systems. Therefore, the aim of this study was to trace the fate of metamitron in a water-sediment system using 13 C-isotope labeling. Mineralization of metamitron was high and accounted for 49% of 13 C 6 -metamitron equivalents at the end. In contrast, only 8.7% of 13 C 6 -metamitron equivalents were mineralized in the water only system demonstrating the key role of sediment for biodegradation. Metamitron disappeared from the water on day 40 and was completely removed from the sediment on day 80. This agrochemical was utilized as carbon source by microorganisms as shown by the incorporation of the 13 C label into microbial amino acids and finally into biogenic residues. The latter amounted to 24% of 13 C 6 -metamitron equivalents at the end. However, 17% of 13 C 6 -metamitron equivalents were detected in xenobiotic non-extractable residues (NER) with a release potential and delayed risk for the environment. Metamitron was degraded via two pathways, initially via 4-(dimethylimino)-3-methyl-6-phenyl-1,2,4-triazin-5(4H)-one, which might be related to growth, and later via desamino-metamitron, which can be attributed to starvation. [ABSTRACT FROM AUTHOR]

Metamitron is one of the most commonly used herbicide in sugar beet and flower bulb cultures. Numerous laboratory and field studies on sorption and degradation of metamitron were performed. Detailed biodegradation studies in soil using 13 C-isotope labeling are still missing. Therefore, we aimed at providing a detailed turnover mass balance of 13 C 6 -metamitron in soil microcosms over 80 days. In the biotic system, metamitron mineralized rapidly, and 13 CO 2 finally constituted 60% of the initial 13 C 6 -metamitron equivalents. In abiotic control experiments CO 2 rose to only 7.4% of the initial 13 C 6 -metamitron equivalents. The 13 C label from 13 C 6 -metamitron was incorporated into microbial amino acids that were ultimately stabilized in the soil organic matter forming presumably harmless biogenic residues. Finally, 13 C label from 13 C 6 -metamitron was distributed between the 13 CO 2 and the 13 C-biogenic residues indicating nearly complete biodegradation. The parallel increase of 13 C-alanine, 13 C-glutamate and 13 CO 2 indicates that metamitron was initially biodegraded via the desamino-metamitron route suggesting its relevance in the growth metabolism. In later phases of biodegradation, the “ Rhodococcus route” was indicated by the low 13 CO 2 evolution and the high relevance of the pyruvate pathway, which aims at biomolecule synthesis and seems to be related to starvation. This is a first report on the detailed degradation route of metamitron in soil. [ABSTRACT FROM AUTHOR]

In 2013 and 2014, field trials were conducted at six environments in Germany to evaluate the efficacy of a new ALS-inhibiting herbicide containing foramsulfuron and thiencarbazone-methyl (F/T) for weed control in sugar beet cultivation. Five herbicide strategies with different application frequencies of F/T (50 g foramsulfuron ha-1 + 30 g thiencarbazone-methyl ha-1) and a classic herbicide strategy with three applications of phenmedipham (75 g ai ha-1), desmedipham (59 g ai ha-1), ethofumesate (94 g ai ha-1), lenacil (34 g ai ha-1) and metamitron (700 g ai ha-1) were compared. The efficacy of the classic herbicide strategy was between 84 and 99% due to surviving Chenopodium album L., Matricaria recutita L., Mercurialis annua L. and Solanum tuberosum L. Average efficacy of F/T was 95% in the single application treatment. Strategies with two applications combining classic herbicides and F/T achieved an efficacy beyond 97%. This points to an increased flexibility of weed control in sugar beet. [ABSTRACT FROM AUTHOR]

Large-scale ZnO nanoflowers assembled from numerous thin and uniform nanosheets with a thickness of around 20 nm, were successfully prepared through a facile one-step hydrothermal synthesis route by using zinc acetate, sodium citrate and sodium hydroxide in water solution. The method was simple, green and effective. The obtained ZnO nanoflowers exhibited remarkable photocatalytic acitivity and good cycle stability for the degradation of metamitron under a 300 W of Osram ® ultra-vitalux lamp light emitting UV and visible radiation over 300–600 nm. UV–vis spectrophotometery was used to measure the rate of photodecomposition of metamitron. The results indicate that about 97% of the metamitron disappeared in the suspension of flower-like ZnO microspheres within four hours, and the degradation efficiency were not changed even after 5 cycle times. [ABSTRACT FROM AUTHOR]

Heterogeneous photocatalysis offers an alternative for the treatment of wastewater containing refractory pollutants. The photocatalytic degradation of metamitron and metribuzin, asymmetrical triazine compounds used worldwide as herbicides, was investigated in aqueous suspension of different commercial TiO 2 nanopowders with different composition of anatase/rutile phases, using artificial UV-A light. In addition, we have studied the role of the most important operating parameters (catalyst loading, effect of electron acceptor, pH, light intensity, initial concentration of pollutants, and interfering substances) on the photooxidation of both herbicides. TiO 2 P25 (70% anatase/30% rutile) was found to be highly active for herbicide decomposition. The progress of photocatalytic degradation of both herbicides has been observed by monitoring the change in substrate concentration using HPLC/MS 2 . Results showed that the addition of TiO 2 in tandem with an electron acceptor like Na 2 S 2 O 8 strongly enhances the degradation rate of metamitron and metribuzin in comparison with photolytic test. The degradation of these herbicides followed a pseudo-first order kinetics. The time required for 50% degradation was lower than 8 min for both. Thus, complete disappearance was achieved after 30 min of illumination in the TiO 2 /Na 2 S 2 O 8 system. Both herbicides were rapidly deaminated. [ABSTRACT FROM AUTHOR]

Novel sensitive voltammetric methods for determination of herbicide metamitron were developed using polished and mercury meniscus-modified silver solid amalgam electrode (p-, m-AgSAE) and boron-doped diamond electrode (BDDE). It was found that metamitron yields one analytically utilizable reduction (AgSAEs) and one oxidation (BDDE) signal. All three tested working electrodes connected to different voltammetric techniques were found to be appropriate for the analysis of the herbicide. The optimum conditions for metamitron determination were ascertained in Britton-Robinson buffer solution of pH 2.0 (m-AgSAE, BDDE) and in 0.05 mol dm HSO (p-AgSAE), respectively, with the limits of detection 3.6 × 10 mol dm (m-AgSAE), 1.0 × 10 mol dm (p-AgSAE), and 1.2 × 10 mol dm (BDDE). Calculated values of relative standard deviations of repeated determinations ( n = 5) in various concentration levels of metamitron did not exceed 5 % for either of the tested electrodes. Finally, practical applicability of newly proposed methods was verified by the analysis of pesticide preparation and spiked river water. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

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Using a combination of experiments and molecular simulations, the solid–liquid equilibrium data of MET in 13 pure solvents were analyzed. [Display omitted] • The solid–liquid equilibrium data of herbicide metamitron in thirteen pure solvents were evaluated gravimetrically. • All solubility data were fitted with four classical thermodynamic models. • The mixing thermodynamic properties of metamitron in thirteen pure solvents were calculated. • Molecular simulations are utilized to analyze the interactions of solute itself, solvent itself, and solute–solvent. Metamitron (MET), a highly water-soluble herbicide for sugar beets, has posed a significant threat to aquatic species due to its high solubility in water; therefore, understanding its solid–liquid phase equilibrium data in different solvents is essential for the future development of more environmentally friendly forms. In this study, the solubility data of MET in 12 pure solvents were determined gravimetrically and analyzed using theoretical methods (primarily Molecular electrostatic potential surface analysis, Hirshfeld surface analysis, Reduced Density Gradient analysis, radial distribution function, and solute–solvent interaction energy) to further investigate the solid–liquid equilibrium behavior. Although MET's high solubility in water contributes to environmental contamination, its value is low in comparison to that of other organic solvents. Four models, including the Apelblat equation, the λh equation, the van't Hoff equation, and the NRTL, were used to examine all solid–liquid equilibrium data, and an ARD% below 5 confirmed its good correlation. The MET solubility data is anticipated to provide solid guidance for the future development of more effective and environmentally acceptable green formulations. [ABSTRACT FROM AUTHOR]

This paper aims at developing and validating a convenient, rapid, and sensitive method for estimation of metamitron from soil samples.Determination andquantification was carried out by Gas Chromatography on microcapillary column with an Electron Capture Detector source. The compound was extracted from soil using methanol and cleanup by C-18 SPE. After optimization, the method was validated by evaluating the analytical curves, linearity, limits of detection, and quantification, precision (repeatability and intermediate precision), and accuracy (recovery). Recovery values ranged from 89 to 93.5% within 0.05- 2.0 µg L−1 with average RSD 1.80%. The precision (repeatability) ranged from 1.7034 to 1.9144% and intermediate precision from 1.5685 to 2.1323%. Retention time was 6.3 minutes, and minimum detectable and quantifiable limits were 0.02 ng mL−1 and 0.05 ng g−1, respectively. Good linearity (R2=0.998) of the calibration curves was obtained over the range from 0.05 to 2.0 µg L−1. Results indicated that the developed method is rapid and easy to perform, making it applicable for analysis in large pesticide monitoring programmes. [ABSTRACT FROM AUTHOR]