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The work presents results of the determination of metribuzin content in commercial pesticide formulations by applying chronopotentiometry with thin film mercury electrode as an electrochemical sensor. In the analyzed pesticide formulations, a single well defined reduction peak of metribuzin is observed at the potential around -880 mV. The content of the herbicide in commercial formulations is determined using the calibration curve method, by applying the initial potential of -0.21 V, and the final potential of -1.10 V. Recovery values based on the declared and found content of the active ingredient are in the range from 100.67% to 101.68%, with the values of relative standard deviation lower than 1.00%, indicating high accuracy and precision of the presented method. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 46009]

Objective: To evaluate the acute toxicity effect of metribuzin at low dose on liver of mother rabbits and its fetus. Methods: Pregnant female rabbits Oryctolagus cuniculus were divided into three groups (n=5). The first group of non-treated pregnancy rabbits served as control; the second group of pregnancy rabbits were treated with 1/100 LD50 of metribuzin and the third group of pregnancy rabbits were treated with 1/50 LD50 of metribuzin. Metribuzin was added in their drinking water for 60 d before and during pregnancy. Levels of liver malondialdehyde, liver glutathione S transferase, serum glutamic oxalacetic transaminase and serum glutamic- pyruvic transaminase were determined. Liver reduced glutathione level was also determined by a colorimetric method. And hepatic homogenate was analyzed by HPLC analysis to determine the existence of traces of metribuzin. Results: Results revealed a significant increase in level of liver malondialdehyde, glutathione S transferase, serum glutamic oxalacetic transaminase and serum glutamic-pyruvic transaminase activities in mother and fetuses rabbits of both metribuzin treatment groups as compared to the control group. However the level of reduced glutathione was decreased in mother and fetuses rabbits of both groups treated with metribuzin compared to control group. Also, the results obtained by HPLC technique showed the presence of trace metribuzin in liver cells of mothers and fetuses rabbits of the both metribuzin treated groups. Conclusions: In conclusion, this study shows that exposure to metribuzin at low concentrations causes a acute toxicity in liver of mother rabbits and its fetus, also the trace of the metribuzin detected in the liver is the origin of possible malformation of the fetuses or abortion of the rabbits.

Soil texture and other physical and chemical characteristics of soil are important factors influencing the retention of herbicides in soil ecosystems. A laboratory experiment was conducted to estimate the response of proteolytic microorganisms to applications of metribuzin in different types of soil (loamy and sandy) in terms of density and protease activity. The following concentrations were tested: 12.0, 24.0, 120.0 and 1200.0 mg a.i.kg-1 soil. Samples were collected 7,14 and 30 days after treatment with metribuzin. Metribuzin did not affect the number of proteolytic microorganisms in loamy soil. In sandy soil, their number was reduced 26.7% by the highest concentration 7 days after application. Protease activity was reduced in both types of soil on the 7th and 14th day and the percentage of reduction was 21% for loamy soil and 29.9% for sandy soil. Statistical analysis of data showed that the correlation between test parameters was positive in both types of soil (r2=1 for loamy soil, and r2=0.81 for sandy soil). The study shows that metribuzin causes a passable impact on microbial population and enzymatic activity which depends on the type of soil.

Weeds are highly competitive to the crops for nutrient and water from soil, sunlight, space and also harbour many insect-pest and diseases, consequently lead to drastic yield reduction. Pisum sativum is sensitive to the most of the potential post emergence herbicides and thus, effective weed management is a difficult assignment particularly the later flush of weed emergence. The identification of herbicide resistant genotypes is the potential way to develop herbicide tolerant varieties as well as to control weeds and minimise yield losses. So far no report is available for herbicide tolerant genotypes in field pea. Therefore, an attempt has been made to identify the genotypes as a source of resistance to the post-emergence herbicide metribuzin. Total 822 genotypes were examined for their sensitivity under preliminary screening against metribuzin at 0.5 kg ai/ha during the winter season of 2015-16. Of the tested genotypes, a set of 85 promising genotypes were re-evaluated with same dose during the winter season of 2016-17 with visual phyto-toxicity score. The results of experiment revealed that there was a huge amount of genetic variation for tolerance against metribuzin in field pea. The frequency distribution grouped the genotypes as tolerant (1), moderately tolerant (5), susceptible (18), and highly susceptible (61) categories. None of the genotypes showed highly tolerant reaction. Notably, accession P-637 witnessed tolerance and other five accessions, viz. P-729, P-647, P-1075, P-2016, and P-1448-2 registered moderately tolerance reaction against metribuzin. Hence, aforesaid promising genotypes may be utilized as donor to speed up breeding for development of herbicide tolerant varieties in field pea and in other genetical studies too.

Contemporary farming practices and rapid industrialization over the last few decades, have raised significant soil and water pollution with extreme toxic effects to humans and ecosystems. The widespread and inefficient use of pesticides, which surpass the soil’s self purification capability, has accelerated soil pollution. In this study, wheat straw biochar was obtained using the traditional pyrolysis technique and its characterization; in addition, the adsorption efficiency of metribuzin was investigated. Biochars’ physical and chemical characteristics were qualified using scanning electron microscopy and Fourier transform infrared spectroscopy. A batch sorption test and liquid chromatography coupled with mass spectrometry were also used to assess the biochar efficiency. SEM and FTIR confirmed the highly reactive surfaces of biochar, establishing efficient biomass conversion in low-oxygen conditions. The adsorption process showed best fit with pseudo second-order kinetic and Langmuir models, suggesting a chemisorption procedure and monolayer-type removal. Regarding its environmental and agricultural application, wheat straw biochar can be advanced as a recommendation solution for further research, which is fundamental for soil rehabilitation and the immobilization of contaminations.

In order to establish the selectivity of the herbicide Flumioxazin - 500 g/kg (Pledge 50 WP) in the experimental field of Experimental Station on Soybean - Pavlikeni, field experiment with soybean variety "Srebrina" was conducted. The study was conducted on average leached chernozem, and includes variants: V1 - Control - untreated; V2 - Flumioxazin - 500 g/kg (Pledge 50 WP) at doses of 80 and 120 g/ha applied pre-emergence and standard - Metribuzin - 700 g/kg (Zino 70 WP) - in the dose - 500 g/ha; V3 - Flumioxazin - 500 g/kg (Pledge 50 WP) at doses of 80 and 120 g/ha applied in growth stage BBCH 13 of the culture and standard - Imazamox 40 g/l (Pulsar 40) - in the dose – 0.5 l/ha + Dach adjuvant at a dose of 1.0 l/ha. Based on the deduced trial and the analysis of the obtained results can draw the following conclusions: Flumioxazin - 500 g/kg (Pledge 50 WP) at the tested doses of 80 and 120 g/ha has high selectivity (score 1) and did not adversely affect the structural elements of the yield of the tested soybean variety "Srebrina", the differences are being statistically insignificant (P=0.05), compared to Metribuzin - 700 g/kg (Zino 70 WP). Flumioxazin - 500 g/kg (Pledge 50 WP) can be used to treatment soybean after sowing before emergence of the crop; Pledge 50 WP applied at a dose of 80 g/ha, in soybean in growth stage BBCH 13, had from weak to medium-strong phytotoxic effect (score 3-4) resulting in shortening and thickening of the nerve, pleating and dorsal twisting at the base of the leaves with a chlorotic crown at its periphery. A slight lag in plant growth is found - the stem is short and slightly thickened. By increasing the dose of herbicide 120 g/ha observed symptomatic damage intensify - score 5; The limited selectivity of Pledge 50 WP applied in growth stage BBCH 13 degrades the viability of soybean plants, while the structural elements of yield are practically close (from -2.5 to +9.5%) compared to those reported for Pulsar 40 in the dose – 0.5 l/ha + Dach adjuvant 1.0 l/ha used as standard. [ABSTRACT FROM AUTHOR]

Four field experiments were conducted at Horticulture Research Station, El-Kanater El-Khiria, Kalubia governorate in two successive winter seasons 2016/17 and 2017/18. First, two of them were carried out to determine the period required for weed free maintenance after carrot sowing to produce the maximum yield and the long of weed competition period which can be allowed without reduction in the yield. Each experiment contained twelve treatments i.e six weed free periods at 2, 4, 6, 8 and 10 weeks after sowing and for the whole season and six treatments of weed competition period at 2, 4, 6,8 and 10 weeks from sowing and for the whole season. Second, of them two field experiments were carried out to evaluate the efficacy of some promising pre emergence soil acting herbicides on weeds and root yield of carrot. Each experiment including seven weed control treatments namely hand weeding at twice, metribuzin at the rate of 100 g/fed., linuron at the rate of500cm3/fed., pendimethalin at rate 1.7 liter/fed., butralin at rate.2.5 liter/fed., as post sowing pre- emergence, prometryn the rate of 1.25 liter./fed. as post sowing and well as the unweeded treatment. The main findings showed that weed infestation for whole season reduced yield of carrot per fed. by 47.1 and 47.0% in both seasons, respectively, than weed free for whole season treatment. Mathematized models which given the relationship between weed infestation periods and carrot yield show that quadratic equation was the best model to predict yield losses due to weed competition is showing that the critical periods length of weed competition nine weeks period from sowing which is required to be eliminates to obtain the maximum carrot yield of carrot without reduction. Weed free for all season gave the best value for all characters per faddan. In the second study, results show that the use of linuron at the rate of 500 cm3/fad gave the highest controlling percentages of the annual broad leaf and grassy weeds through this period with the highest values of carrot yield and can be advised for weed control in mentioned critical period of carrot. At harvest there is no herbicides residues were detected in the edible carrot yield. [ABSTRACT FROM AUTHOR]

The excessive use of the metribuzin herbicide is contaminating groundwater and damaging non-target plants and organisms. There is therefore a need for safer formulations of the herbicide. Here we encapsulated metribuzin by interfacial deposition of the pre-formed polymer. Results show that the encapsulation efficiency of metribuzin reached 83.2%. Nanocapsules remained stable in the suspension without any aggregation or decomposition. Nanocapsules containing metribuzin induced less chromosome aberration and higher mitotic index values than the pure metribuzin. We conclude that herbicide encapsulation in polycaprolactone nanocapsules is safer for food and the environment. [ABSTRACT FROM AUTHOR]

Purpose: Persistence of herbicides in soil is a major concerning world issue due to their negative impacts on environment and human health. Laboratory and bioassay experiments were conducted to evaluate the effects of municipal waste compost (MC) and sheep manure (SM) on metribuzin degradation and phytotoxicity of this herbicide. Methods: In degradation studies, soil samples were mixed separately with amendments at a rate of 2.5% (w/w) and metribuzin at a concentration of 5 mg kg−1 soil was used for fortification of selected samples. A liquid extraction method was chosen and final extracts were analyzed by HPLC. In bioassay study, the phytotoxic effects of different concentrations of metribuzin (0, 0.01, 0.05, 0.1, 0.2, 0.4, 0.8 and 1 mg kg−1 soil) on oilseed rape (Brassica napus L.) were evaluated. Results: The results indicated 88.8% degradation of metribuzin in MC during 120-day period followed by SM recording 72.2%, compared to non-amended soil where 59.8% of metribuzin were removed. The half-life was 119.48 days in non-amended soil as compared to 87.72 and 103.43 days in MC and SM application, respectively. MC was the most efficient treatment to accelerate metribuzin dissipation from the soil. Bioassay results showed that metribuzin residues had a negative effect on root and shoot biomass of oilseed rape. However, the root parameter was more sensitive than the shoot. Conclusions: It could be concluded that application of organic amendments to agricultural soils is an eco-friendly strategy to improve soil conditions and non-target crop protection as well as the removal of herbicide residues from soil environment. [ABSTRACT FROM AUTHOR]

Multiple field experiments and a controlled-environment temperature study were conducted to investigate soil and weather conditions responsible for herbicide phytotoxicity in lentil (Lens culinaris Medik.) from post-emergent application of metribuzin. A linear relationship was observed between plant injury (% necrosis) and metribuzin rate in all 12 environments, but in only 11 environments for anthesis dry weight and nine environments for both plant density and grain yield. Grain-yield reduction from label metribuzin rates of 135 g a.i. ha–1 for sand and 285 g a.i. ha–1 for clay ranged from 0% to 32% and 0% to 67%, respectively, across all environments. Principal component analysis of soil and weather factors around the time of herbicide application suggested that metribuzin-induced plant damage in lentil was due to a combination of multiple soil and weather factors. However, heavy rainfall within 10 days of herbicide application, particularly on light-textured soils or where soil moisture was low, was most strongly linked to plant damage. Experiments targeting the impact of reductions in temperature post-metribuzin application showed no effect, and of light intensities pre- and post-metribuzin application showed low effects on plant-damage measures. Because rainfall in the 10 days after application is a major determinant of metribuzin damage in winter-grown lentil in southern Australia, a higher level of selective tolerance to metribuzin than that present in commercial cultivars is needed for its safe post-emergent use. Early and late measures of plant damage will be required to assess accurately plant tolerance to post-emergent metribuzin application in lentil. Lentil is a pulse crop of expanding importance in Australia, but production is limited by weed competition and a lack of safe and effective herbicides. Metribuzin is a broad-spectrum herbicide used in lentil; however, multiple soil and weather conditions exacerbated plant damage, particularly heavy-rainfall events within 10 days of post-emergent application on light-textured soils low in soil moisture. This research highlights the need for the development of lentil cultivars with a higher level of tolerance to metribuzin under Australian conditions. [ABSTRACT FROM AUTHOR]

To evaluate the effect of herbicide band application and cultivator on weed control, yield and yield components of potato, an experiment was conducted using factorial arrangement based on randomized complete block design (RCBD) with four replications at Research Field of Ferdowsi University of Mashhad, Mashhad, Iran during 2015. Experimental factors included cultivator at two levels (with and without cultivator application) and herbicide treatments at six levels, including 1. Pre plant herbicide application (Pendimethalin) + broadcast application of post emergence herbicide (Metribuzine), 2. Pre plant herbicide application (Pendimethalin) + band application of post emergence herbicide (Metribuzine), 3. Pre plant herbicide (Pendimethalin) alone, 4. Broadcast application of post emergence herbicide (Metribuzine) alone, 5. Band application of post emergence herbicide (Metribuzine) alone, and no herbicide treatment. The results showed that application of Pendimethalin + broadcast or band application of Metribuzine reduced total weed density and total weed biomass and increased tuber weight, tuber number and total biomass of potato. The highest tuber yield was observed in Pendimethalin + broadcast (41 ton ha-1) and band application of Metribuzine (36 ton ha-1), and the lowest tuber yield was observed in no herbicide (16 ton ha-1) and Pendimethalin alone (18.75 ton ha-1). It was concluded that interaction of cultivator and herbicide application had no significant effect on total weed density, total weed biomass and tuber and biomass yield of potato, due perhaps to inadequate repeat of cultivator application. [ABSTRACT FROM AUTHOR]

BACKGROUND Amaranthus palmeri S. Wats is among the most problematic annual broadleaf weed species in the USA, including in Kansas. In late summer 2015, seeds of an A. palmeri population (MHR) that had survived field‐use rates of 2,4‐D were collected from Barton County, KS, USA. The main objectives were to: (i) confirm and characterize 2,4‐D resistance in a MHR population; (ii) characterize the resistance profile of the MHR population in relation to a multiple herbicide‐susceptible (MHS) population to glyphosate, chlorsulfuron, atrazine, mesotrione, fomesafen; and (iii) determine the effectiveness of alternative POST burndown herbicides for controlling MHR population. RESULTS: The MHR population had 3.2‐fold resistance to 2,4‐D. In addition, the MHR population also exhibited multiple resistance to glyphosate (11.8‐fold), chlorsulfuron (5.0‐fold), atrazine (14.4‐fold), and mesotrione (13.4‐fold). Furthermore, the MHR population also showed reduced sensitivity to fomesafen (2.3‐fold). In a separate study, dicamba with glyphosate, atrazine or fluroxypyr + 2,4‐D, and paraquat alone or with atrazine, metribuzin, saflufenacil or 2,4‐D provided ≥ 99% injury to the MHR population. Similarly, saflufenacil alone or with atrazine, metribuzin or 2,4‐D, and glufosinate alone or with glyphosate + 2,4‐D, and glyphosate + dicamba, and a premix of bicyclopyrone + atrazine + mesotrione + S‐metolachlor also effectively controlled the MHR population. CONCLUSION: This research confirms the first global case of an A. palmeri population from Kansas with multiple resistance to 2,4‐D, glyphosate, chlorsulfuron, atrazine and mesotrione, and reduced sensitivity to fomesafen. Dicamba, glufosinate, paraquat, and saflufenacil alone or in tank‐mixtures with PRE herbicides effectively controlled this MHR population. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Weed control is the most important constraint of autumn-sown chickpea production. Field experiments were conducted at three sites to evaluate the yield response of autumn-sown rainfed chickpea and weed control with PRE pendimethalin, POST pyridate, PRE isoxaflutole, preemergence (PRE) and postemergence (POST) of imazethapyr through hand-weeded, untreated and weed free checks. The results showed that pyridate was the safest option for weed control in chickpea. The highest grain yield of chickpea was obtained with application of pyridate followed by isoxaflutolein three sites. Imazethapyr and metribuzin caused higher visual injuries than the other treatments. Furthermore, the applications of pyridate, isoxaflutole, metribuzin, and pendimethalin, as well as PRE and POST imazethapyr were found to reduce the total weed densities (averaged for three locations) by as much as 76, 75, 75.4, 43, 64, and 64.5% within 30 days after treatments, respectively. [ABSTRACT FROM AUTHOR]

Weed control based on herbicides is essential to guarantee high levels of crop productivity. However, these compounds can affect ecosystems and non-target crops. Therefore, a research was carried out in order to investigate the effect of metribuzin (ME) on the capacity of Zea mays L. (maize) to acquire iron (Fe). ME reduced the chlorophyll content, the concentration of phytosiderophores (PSs) released by roots and their Fe content. Both the shoots and roots of ME-treated plants showed increases in ammonia () concentrations. This effect was ascribed to the decreases in the activity of glutamine synthetase (GS; EC 6.3.1.2) and glutamine amide-2-oxoglutarate aminotransferase (GOGAT; EC 1.4.1.14). The results indicate that the interference exerted by ME on nitrogen organication was the cause of the drop in the PSs release and of the reduction in the Fe content. [ABSTRACT FROM AUTHOR]

Goosegrass (Eleusine indica L. Gaertn.) is a problematic C4 weedy grass species, occurring in the warmer regions of the world where it is difficult to selectively control without injuring the turfgrass. Furthermore, control efficacy is affected by plant maturity. End-user options for satisfactory goosegrass control has decreased; thus, the need for developing management techniques to improve the selectivity of POST goosegrass control options in turfgrass systems is ever increasing. One possiblemeans of providing control, yetmaintaining turf quality is immediately incorporating applied products via irrigation. Greenhouse and field trials were conducted in Pickens County, SC,with the objectives of 1) evaluating turfgrass injury following use of POST goosegrass control options; 2) assessing if irrigating (0.6 cm) immediately following the herbicide application reduces injury of 'Tifway 419' bermudagrass [Cynodon dactylon (L.) Pers. 3 Cynodon transvaalensis Burtt-Davy]; and 3) determining if immediate irrigation influences goosegrass control at one- to three-tiller and mature growth stage. Following the application of herbicide treatments, irrigation was applied (+) or not applied (L). Treatments included the following: control (+/-irrigation); topramezone at 12.3 g a.i./ha (+/-irrigation); metribuzin at 420 g a.i./ha (+/-irrigation); and topramezone plus metribuzin (+/-irrigation) at 12.3 and 420 g a.i./ha. Irrigation treatment hadminimumeffect on greenhouse-grown goosegrass biomass, all treatments provided >85% control of 1- to 3- tiller goosegrass plants. However, control for mature plants was <50% for topramezone- and 60% to 70% for metribuzin-containing treatments. In field studies, at 1 week after treatment (WAT), the irrigated metribuzin and topramezone plus metribuzin had ≈37% and '16%, respectively, less goosegrass control vs. nonirrigated treatments. At 2WAT, irrigated metribuzin and irrigated topramezone plus metribuzin--treated plots, had ≈50%less mature goosegrass control vs. nonirrigated treatments. Irrigated herbicide treatments, however, experienced ≈23% less turfgrass injury at this time. At 4 WAT, irrigated metribuzin- and irrigated topramezone plus metribuzin--treated plots experienced reducedmature goosegrass control by ≈65% and ≈59%, respectively. Overall, incorporating POST herbicide applications via 0.6 cm of irrigation reduced turfgrass injury by at least 20% for all herbicide treatments, while maintaining goosegrass control. [ABSTRACT FROM AUTHOR]

• WO 3 particles could promote the stability and electrocatalytic performance of PbO 2. • The PbO 2 /WO 3 electrode exhibited up to 99.5% of metribuzin decontamination. • Current density and initial concentration have significant effect on metribuzin removal. • Up to 15 degradation byproducts of metribuzin were acquired and identified. • Three degradation sub-pathways were clearly presented in mineralization mechanism. In this work, we fabricated PbO 2 /WO 3 composite electrode through composite electrodeposition method and employed it in electrocatalytic degradation of metribuzin. The effects of WO 3 particles on surface morphology, structure and electrochemical characters of PbO 2 electrodes were investigated. Different from PbO 2 electrodes, the PbO 2 /WO 3 composite electrodes owned higher oxygen evolution overpotential, longer service life and higher hydroxyl radicals generation performance. The effect of key operating parameters, for instance, current density, initial metribuzin concentration, initial pH values, and supporting electrolyte concentration, upon electrochemical removal process of metribuzin were studied. The current density and initial metribuzin concentration exerted prominent effects on electrochemical degradation of metribuzin. Kinetic analysis indicated that the electrochemical decomposition of metribuzin was a pseudo-first-order reaction. The byproducts during metribuzin degradation process were identified, several aromatic products and inorganic ions were generated along with the reaction time. Finally, the electrochemical pathways of metribuzin degradation at the PbO 2 /WO 3 composite electrode were proposed based on the identified reaction byproducts, which were separated into three parallel sub-pathways according to the different degradation reactions by hydroxyl radicals, and quantities of hydroxylation, oxidation, demethylation, deamination, and addition reactions' products were generated. All the byproducts were finally decomposed into inorganic H 2 O, CO 2 , NO 3 −, and NH 4 +. [ABSTRACT FROM AUTHOR]

In this study, we used two biochars (BC) produced from grapevine pruning residues (BCgv) and red spruce wood (BCrs), two hydrochars (HC) from urban pruning residues (HCup) and the organic fraction of municipal solid wastes (HCuw), and two vermicomposts (VC) obtained vermicomposting digestates from buffalo manure (VCbm) and mixed feedstock (VCmf). Adsorption kinetics and isotherms of metribuzin onto these materials were performed. Sorption kinetics followed preferentially a pseudo-second-order model, thus indicating the occurrence of chemical interactions between the sorbate and the adsorbents. Adsorption constants were calculated using the Freundlich and Langmuir models. Metribuzin sorption data on BCgv and both HC fitted preferentially the Freundlich equation, whereas on the other materials data fitted both isotherms well (r > 0.95). Metribuzin sorption capacity of the materials followed the trend BC > HC > VC. Sorption constants of metribuzin normalised per organic carbon content (KOC) on BCgv, BCrs, HCup, HCuw, VCbm and VCmf were 561, 383, 251, 214, 102 and 84 L kg−1, respectively. A significant positive correlation (P = 0.016) was calculated between distribution coefficients (Kd) of all materials and the corresponding organic carbon contents, thus indicating a prominent role of the organic fraction of these materials in the adsorption of metribuzin. [ABSTRACT FROM AUTHOR]

Three plot field trials (2014–2017) were carried out in Prague. The aim of the study was to evaluate the efficacy of herbicides against volunteers from Clearfield® (CL) and conventional oilseed rape (Brassica napus L.) in winter wheat (Triticum aestivum L.) and to quantify the effect of herbicide and application time on wheat yield. Autumn control (diflufenican, isoproturon, flumioxazin, metribuzin, penoxsulam, florasulam, chlorsulfuron were tested) of volunteer oilseed rape (OSR) was more effective than using the spring herbicide treatments (2,4-D, iodosulfuron, amidosulfuron, tritosulfuron, florasulam), especially against the CL OSR variety. Full control of both CL and conventional OSR was recorded only on plots treated by the combination of metribuzin + diflufenican + flufenacet. The most effective spring herbicide was 2,4-D, but its efficacy (82–95%) depended on the growth stage of OSR and application rate. Efficacy of spring herbicides against CL OSR was lower compared to that against conventional OSR, but there were large differences among tested herbicides. Efficacy of tested ALS inhibitors against volunteer CL OSR ranged between 20% (chlorsulfuron) and 77% (tritosulfuron + florasulam). Seed production of volunteer OSR ranged between 0 and 37,000 seeds m−2 while depending strongly on time of sowing and weather conditions during the autumn and winter. No seed of CL OSR matured on plots treated by metribuzin in autumn or 2,4-D at application rate 377 g ha−1 in spring. Volunteer OSR in competition with winter wheat caused almost 50% wheat yield loss on the untreated check. Although the efficacy of most spring herbicide treatments on conventional OSR was good, the competition effect of OSR on wheat during winter and early spring caused about 0.52–0.86 t ha−1 greater yield loss compared to autumn herbicide treatments. • Autumn herbicide treatments were more effective than spring treatments. • The most effective and fastest acting autumn-tested herbicide was metribuzin. • Volunteer oilseed rape produced up to 37,000 seeds m−2 in winter wheat. • Volunteer oilseed rape caused almost 50% reduction in wheat yield. • If 2,4-D was applied at a rate of 377 g ha−1, no oilseed rape seed matured. [ABSTRACT FROM AUTHOR]

Despite the high amphibian biodiversity and increasing pesticide use in tropical countries, knowledge on the sensitivity of tropical amphibians to pesticides remains limited. The aim of this study was to evaluate the acute toxicity of the active ingredients of four of the main herbicides used in Brazilian sugarcane production to tadpoles of two tropical frog species: Physalaemus cuvieri and Hypsiboas pardalis. The calculated 96 h-LC50 (median lethal concentration; in mg a.s./L) values for P. cuvieri and H. pardalis were 4.4 and 7.8 (acetochlor); 15 and <10 (ametryn); 115 and 106 (glyphosate); and 85 and 68 (metribuzin), respectively. These toxicity values demonstrated little interspecies variation and the toxicity of the herbicides appeared to be at least partly related with the respective octanol-water coefficient. Published acute toxicity data of fish and amphibians for herbicides were also compiled from the US-EPA ECOTOX database. These data indicated little difference in herbicide sensitivity between tropical amphibians and both non-tropical amphibians and fish. These findings indicate that temperate (fish and amphibian) herbicide toxicity data are also protective for tropical amphibians. Constraints in such extrapolations and indications for future research are discussed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Biocompatible CS-PC BPE was used to the electrochemical sensing for the first time. • The CS-PC BPE/GCE revealed excellent electrocatalytic activity towards MNZ and MTZ. • High selectivity for MNZ and MTZ and nanomolar level detection limit were observed. • The method was successfully applied for real sample analysis. Abstract Development of novel biocompatible sensor material suitable for modest, cost-effective, and rapid practical application is a demanding research interest in the field of electroanalytical chemistry. In this context, for the first time, we utilized biocompatible chitosan-pectin biopolyelectrolyte (CS-PC BPE) complex for the simultaneous electroreduction of an important antibiotic drug (metronidazole-MNZ) and herbicide (metribuzin-MTZ). This sensor reveals an attractive welfares such as simplicity, biocompatibility, and low production cost. Under optimized experimental conditions, the electroanalytical investigation confirmed that CS-PC BPE modified glassy carbon electrode (CS-PC BPE/GCE) was found to sense MNZ and MTZ in the nanomolar range. Moreover, as-prepared CS-PC BPE/GCE exhibited prominent selectivity, stability, and reproducibility. Additionally, the possible MNZ and MTZ sensing mechanism of CS-PC BPE/GCE have been discussed in detail. Lastly, real sample analysis was also carried out and revealed from several investigations that the CS-PC BPE/GCE is a good electrochemical sensor system for the detection of targeted analytes. [ABSTRACT FROM AUTHOR]

Abstract Hexazinone, metribuzin, and quinclorac herbicides are used extensively throughout Brazil, and they can easily be leached to groundwater sources. Bone char (BC) has been shown to strongly sorb organic compounds and could be used as a sorbent to increase herbicide sorption and decrease leaching, although the better form of application is not known. The aim of this research was to assess the effect of cow BC on the sorption-desorption and mobility of hexazinone, metribuzin, and quinclorac applied to a sandy loam tropical soil under laboratory conditions. The methodology of the sorption-desorption studies was established using a batch equilibrium method, and the treatments were unamended soil, pure BC, and BC-amended soil (at a rate of 5% by weight). Herbicide mobility studies were evaluated by column leaching and soil thin-layer chromatography (TLC). In the column leaching studies, BC was either applied to the surface or incorporated into the 0–10 cm top layer of soil, the latter at a rate of 5% by weight (60 t ha−1). A glass column was prepared for each treatment, and analyses of 14C-herbicides were performed by liquid scintillation counting. Finally, for TLC studies the BC treatments were unamended soil, BC (5% by weight)-amended soil, soil + BC band (1 cm) in the middle, and soil + BC band at the top. We conclude that cow BC is an excellent sorbent to reduce mobility of hexazinone, metribuzin, and quinclorac in a tropical soil through the high sorption of these herbicides, regardless of application form of the material. Thus, it is possible to minimize the pollution of soil-applied herbicide simultaneously, as the BC and thus the herbicides can remain in the soil for a long time. Graphical abstract Unlabelled Image Highlights • Cow bone char increased quinclorac, metribuzin and hexazinone sorption in soil. • Herbicide leaching was decreased with bone char applied to the topsoil and incorporated. • Bone char reduced herbicide mobility in soil thin-layer chromatography. • Bone char can be used as an immobilizer of herbicide contaminated soils. [ABSTRACT FROM AUTHOR]

BACKGROUND Weed competition is a major limitation to worldwide lentil (Lens culinaris Medik.) production in part due to limited effective safe herbicide options. Metribuzin is a photosystem II inhibiting herbicide that provides broad spectrum weed control, however it causes excessive injury in lentil. Dose response analysis of photosystem II inhibiting herbicides and DNA sequencing of the psbA chloroplast gene occurred to quantify the spectrum and mechanism of herbicide resistance in two ethyl‐methanesulfonate (EMS) induced mutant lentils. RESULTS: Compared to susceptible parent PBA Flash, the level of metribuzin resistance was 33‐fold for mutant M043 and 10‐fold for M009. No improvement in resistance occurred in either mutant to bromoxynil, diuron, bromacil and atrazine herbicides. Nucleotide sequencing of the psbA gene of both mutants identified a substitution at position 751 compared to PBA Flash. The resulting deduced amino acid sequence indicated an Ala251Thr substitution as being most likely responsible for the high level of metribuzin resistance. CONCLUSIONS: The Ala251Thr substitution discovered in this study is unique in mutagenized higher plants and the first report of an induced psbA target site mutation in higher plants. This target site metribuzin resistance is likely to have a significant impact on lentil production in Australia and worldwide. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

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Highlights • High-throughput endpoints used to characterize MoA of bifenox and metribuzin in C. reinhardtii. • Concentration-dependent increase in ROS formation by bifenox and metribuzin. • ROS production followed by oxidative damage and alterations in pigment content. • Bifenox and metribuzin affected photosynthesis performance at different extents. • Photosynthetic damage associated with ROS formation and consequent oxidative stress and damage. Abstract The widespread presence of herbicides in the aquatic environment has raised awareness about the need to develop further in depth ecotoxicological risk assessments, more specifically on potential effects on photosynthetic organisms as microalgae. The majority of the information available regarding the toxicity of herbicides towards microalgae is related to traditional toxicological and regulatory-relevant endpoints such as growth inhibition, leaving a significant gap on knowledge regarding underlying interactions and damage to biological targets. In this context, this study aimed to supplement the general toxicity information of bifenox and metribuzin in the microalgae Chlamydomonas reinhardtii using a battery of selected high-throughput methods. This multiple-endpoint approach included the measurement of formation of reactive oxygen species (ROS), alterations in reduced glutathione (GSH) content, formation of lipid peroxidation (LPO), photosystem II (PSII) performance and loss of photosynthetic pigments after 24 h exposure. Results obtained showed that both herbicides caused a concentration-dependent increase in ROS formation, with bifenox showing higher but less reactive ROS. This increase in ROS production by bifenox and metribuzin was followed by alterations in the antioxidant capacity of algae, oxidative damage in the form of LPO and alterations in pigment content. Furthermore, both herbicides impacted the photosynthetic activity of algae, as seen by alterations in the maximum and effective quantum efficiency of PSII, PSII photochemistry and energy dissipation pathways, impact in the water-splitting apparatus and reduction in the electron transport rate. The inhibitory effect of metribuzin on photosynthetic processes/components was larger than that seen for bifenox. The impact of bifenox and metribuzin in the photosynthetic processes of C. reinhardtii seems to be in close association with the formation of ROS and consequent oxidative stress and damage in algal cells. Overall, this study showed that the high-throughput methods developed could successfully characterise both potential Modes of Action and adverse effects of bifenox and metribuzin in C. reinhardtii. [ABSTRACT FROM AUTHOR]

The objective of this study was to optimize the experimental conditions for maximum removal efficiency and minimum operating cost for removal of metribuzin pesticide from aqueous solution. Central Composite Design model was applied as Response Surface Design. In the model, independent parameters were ultraviolet irradiation time, persulfate anion dosage, TiO2 dosage, pH and response parameters were metribuzin removal (%) and operation cost. Analysis of variance (ANOVA) was used to describe the significance level of factors on the multiple performance characteristics considered. It has been found that the most suitable model is the quadratic model to explain the both responses and the correlation coefficient (R2) of the relationship between the actual metribuzin removal and the predicted removal was calculated as 0.9518. As a result of multi‐optimization, removal efficiency of 84.59 (%) and operation cost of 4.44 (€/g) were obtained at ultraviolet irradiation time at 12.03 min, persulfate anion concentration at 4.909 g/L, TiO2 concentration at 0.197 g/L and pH at 4. [ABSTRACT FROM AUTHOR]

Biochars obtained by biomass pyrolysis have been proposed as a soil amendment to improve soil properties and fertility as well as to retain pesticides and other environmental contaminants. The present study investigates the degradation of metribuzin herbicide and its metabolites deamino- (DA), deaminodiketo- (DADK) and diketo- (DK) metribuzin under simulated solar light and dark conditions as well as their mobility using TLC plates coated with soil and soil‒biochar mixtures at 1% and 5% w/w ratio. Biochar was characterised by X-Ray diffraction, porosimetry, scanning electron microscopy and Fourier transform infrared spectroscopy. Degradation under light conditions followed biphasic kinetics, with bi-exponential model fitted better for the soil substrate, while the Gustafson–Holden model was found more appropriate to describe degradation kinetics in 1% soil/biochar mixture. In soil, DA presented the lowest degradation rate (DT50:440.9 h), followed by metribuzin (DT50:208.0 h), DADK (DT50:110.8 h) and DK (DT50:106.5 h). The addition of biochar reduced drastically the degradation or even inhibited the photolytic process for the studied reaction period. The mobility retention factor (Rf) in soil ranged from 0.49 for metribuzin to 0.63 for DADK. The addition of biochar practically immobilises the compounds in the surface layer as Rf ranged from 0.14 to 0.10 for metribuzin and from 0.23 to 0.16 for DADK in soil/biochar mixtures 1% and 5%, respectively. In conclusion, the addition of biochar reduced dramatically the photodegradation rates as well as the mobility of metribuzin and its metabolites due to increased adsorption. [ABSTRACT FROM AUTHOR]

This study aims to examine the potentialities of raw maghnite and acid-activated maghnite (raw- Mag and Mag-H+) for Metribuzin herbicide removal from aqueous solutions. Raw-Mag and Mag-H+ were characterized using various analytical techniques such as NMR, BET, FTIR, FRX, ATD and SEM. The effect of various operating parameters such as contact time, Metribuzin concentration, pH, and adsorbent dose were investigated using raw-Mag and H-Mag in batch adsorption system. The results showed that the maximum adsorption capacity was 70.1 and 55.6 mg/g for raw-Mag and Mag-H+ respectively at pH 2.5, initial Metribuzin concentration of 20 mg/L, adsorbent raw-M and Mag-H+ dosage of 0.5 and 0.2 g/L. The adsorption of Metribuzin herbicide was important in acidic medium for both adsorbents. Furthermore, the adsorption uptake was found to be increased with increase initial concentration. The equilibrium adsorption data were well described by Freundlich and Langmuir isotherms. The kinetic studies showed that the experimental data was best describing by pseudo second order model. The Mag-H+ had above 30% adsorption uptake capacity after four regeneration cycles, this was higher than Raw-Mag. It was observed from the values of thermodynamics parameters such us Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°), that the nature of adsorption is spontaneous. [ABSTRACT FROM AUTHOR]

Highlights • Metribuzin solutions treated by AO-H 2 O 2 , EF and PEF with a BDD/air-diffusion cell. • Two kinetic stages in EF and PEF: uncomplexed and Fe(III)-complexed herbicide. • Overall mineralization by all methods is ensured at current densities ≥100 mA cm−2. • PEF as the best method: total combustion of 0.523 mM metribuzin at pH 3.0 in 420 min. • Heteroaromatic, dimeric and aliphatic by-products degraded by BDD(OH) and OH. Abstract This article reports the electrochemical degradation of the herbicide metribuzin (MTZ) in sulfate medium by advanced oxidation processes like anodic oxidation with electrogenerated H 2 O 2 (AO-H 2 O 2), electro-Fenton (EF) and UVA photoelectro-Fenton (PEF). A boron-doped diamond (BDD) anode was combined with an air-diffusion cathode with ability to produce H 2 O 2. Unprecedented overall combustion was feasible by all methods at a constant current density (j) ≥100.0 mA cm−2. The total organic carbon (TOC) removal achieved by AO-H 2 O 2 was independent from pH within the range 3.0–9.0, whereas the oscillatory dependence of the pseudo-first-order MTZ decay rate constant with this variable was ascribed to adsorption on the BDD surface. In EF and PEF at pH 3.0, 0.50 mM Fe2+ was determined as optimum catalyst content and the MTZ removal showed two consecutive pseudo-first-order kinetic stages. These were related to the fast reaction of the target molecule with OH formed from Fenton's reaction, followed by a slower attack of physisorbed BDD(OH) onto Fe(III)-MTZ complexes. The effect of j and MTZ content on decay kinetics and TOC removal was examined. PEF was the best treatment due to the decomposition of photoactive intermediates by UVA radiation, yielding total mineralization of a 0.523 mM herbicide solution after 420 min of electrolysis at 100.0 mA cm−2. A thorough reaction pathway for MTZ degradation is proposed from the sixteen heteroaromatic by-products and three aliphatic molecules identified by GC–MS and LC-MS/MS. Oxalic and oxamic acids were detected as final carboxylic acids by ion-exclusion HPLC. [ABSTRACT FROM AUTHOR]

Highlights • Four metribuzin degrading bacterial strains were isolated from contaminated soil. • Consortium MB3R was more efficient at degrading metribuzin. • Conditions for optimal biodegradation of metribuzin were determined by Taguchi design of experiment. • Biodegradation of metribuzin by MB3R followed first-order kinetics. • Three intermediate metabolites produced during metribuzin degradation were detected. Abstract Metribuzin (MB) is used for control of weeds in crops like potato, maize and sugarcane. Its extensive and unjudicial use has resulted in various environmental issues; hence it is very critical to remediate this herbicide at the respective point source. Plant associated, MB degrading bacterial strains, Rhodococcus rhodochrous sp. AQ1, Bacillus tequilensis sp. AQ2, Bacillus aryabhattai sp. AQ3 and Bacillus safensis sp. AQ4 were isolated, and a consortium MB3R was developed. For degradation of MB by the consortium MB3R, various parameters i.e., pH, temperature, inoculum density and pesticide concentration were optimized by using Taguchi design of experiment (DOE). MB degradation was dependent upon all the four factors. The contribution of each factor on MB degradation was according to the order: temperature > inoculum density > pH > pesticide concentration. Fitness of Taguchi DOE in forecasting the optimum response, was confirmed experimentally by using optimized levels of the four factors i.e., pH 7.0, temperature 30 °C, pesticide concentration 45 mg l−1 and an inoculum density of 5.0 × 10 5 CFU ml−1 whereby 98.63% MB degradation was observed. Appearance and subsequent degradation of three MB metabolites, desamino-metribuzin (DA), diketo-metribuzin (DK) and desamino-diketo-metribuzin (DADK) during biodegradation by the consortium was observed. [ABSTRACT FROM AUTHOR]

Summer annual grassy weeds such as goosegrass (Eleusine indica L. Gaertn.) continue to be problematic to control selectively with postemergence (POST) herbicides within turfgrass stands. In recent years, reduced performance by certain herbicides (e.g., foramsulfuron), cancellation of goosegrass-specific herbicides (e.g., diclofop-methyl), and cancellation and/or severe use reductions of other herbicides [e.g., monosodium methanearsonate (MSMA)] have limited the options for satisfactory control and maintenance of an acceptable (£30% visual turfgrass injury) turfgrass quality. Currently available herbicides (e.g., topramezone and metribuzin) with goosegrass activity typically injure warm-season turfgrass species. The objectives of this research were to evaluate both 'Tifway 419' bermudagrass [Cynodon dactylon (L.) Pers. 3Cynodon transvaalensis Burtt-Davy] injury after treatment with POST herbicides, and to determine whether irrigating immediately after application reduces turfgrass injury. Treatments were control (± irrigation); topramezone (Pylex 2.8C; ± irrigation); carfentrazone + 2,4-D + dicamba + 2-(2-methyl-4-chlorophenoxy) propionic acid (MCPP) (Speedzone 2.2L; ± irrigation); carfentrazone + 2,4-D+ dicamba +MCPP in combination with topramezone (± irrigation); metribuzin (Sencor 75DF; ± irrigation); mesotrione (Tenacity 4L; ± irrigation); simazine 4L (±irrigation); and mesotrione + simazine (± irrigation). Irrigated treatments were applied immediately with a hand hose precalibrated to apply 0.6 cm or 0.25 inch ('6.3 L). Visual turfgrass injury for combined herbicide treatments for the irrigated plots was 6% 4 days after treatment (DAT), 12% 1 week after treatment (WAT), 17% 2 WAT, and 6% 4 WAT, whereas nonirrigated plots had turfgrass injury of 14% at 4 DAT, 31% 1 WAT, 35% 2 WAT, and 12% 4 WAT. Irrigated pots had normalized differences vegetative indices (NDVI) ratings of 0.769 at 4 DAT, 0.644 at 1 WAT, 0.612 at 2 WAT, and 0.621 at 4 WAT, whereas nonirrigated plots had the lowest (least green) turfgrass NDVI ratings of 0.734 at 4 DAT, 0.599 at 1 WAT, 0.528 at 2 WAT, and 0.596 at 4 WAT. These experiments suggest turfgrass injury could be alleviated by immediately incorporating herbicides through irrigation. [ABSTRACT FROM AUTHOR]

[Display omitted] • New ionic liquid@ covalent organic frameworks were prepared under room temperature. • A fast and sensitive method was established for the determination of six herbicides. • IL@COFs have stable properties and reusability for adsorbed herbicide. • This SPE technique was used to quantify herbicides in water samples. Waters contaminated with pesticides poses a potential hazard to ecosystems and human health, so sensitive and efficient analytical methods are essential for water monitoring. Herein, in order to efficiently extract six commonly used herbicides, a novel ionic liquid covalent organic framework (IL@COF) was prepared using a simple room-temperature synthesis in this study. As an adsorbent for solid phase extraction (SPE), the mesoporous material exhibits rapid adsorption performance for six typical herbicides from water samples. Under the optimal experimental conditions, wide linearities (500 ∼ 20,000 μg L–1) and low limits of detection (prometryn: 17.9 μg L–1; metribuzin: 36.7 μg L–1; bentazon: 14.5 μg L–1; isoproturon: 18.0 μg L–1; acetochlor: 19.6 μg L–1; butachlor: 37.1 μg L–1) for six analytes were obtained via high performance liquid chromatography (HPLC). The adsorbent has stable physical and chemical properties and can be reused for 10 times after effective elution. The applicability of this method is further evaluated by analyzing ten kinds of real water sample. The recoveries of six kinds of herbicides ranged from 85.3 % to 122.9 %. The mechanism of adsorption is the interaction between hydrogen bond acceptor and donor. These results indicate that HPLC after SPE with a new type of IL@COF as the SPE adsorbent is a promising technique for the simultaneous detection of six pesticides in environmental water samples. [ABSTRACT FROM AUTHOR]

Chickpea is an important rotational pulse crop for Saskatchewan field crops. Since 2019, Saskatchewan chickpea production has suffered from a plant health issue following rainfall events around flowering to early podding resulting in apical wilting and eventual branch death. Post-emergence broadleaf weed management in chickpea relies on metribuzin, which can result in variable injury in chickpea. The study objective was to evaluate the effect of metribuzin dose and water stress on chickpea health in the greenhouse. At two weeks after treatment (WAT), chickpea mortality reached 25% for 206 g ai ha−1 (label rate) metribuzin dose and 56% for 413 g ha−1 dose, respectively. Maximum chickpea vegetative chlorosis and necrosis was 81% for the 413 g ha−1 metribuzin treatment and 65% for the 206 g ha−1 treatment. Chickpea longest branch length was reduced from 34 to 26 cm at 8 WAT with the 206 g ha−1 metribuzin treatment. Three weeks of permitting the soil to reach the wilting point and induce symptoms reduced chickpea longest branch length from 38 to 24 cm by 8 WAT. Chickpea pod production was reduced by 75% with the 206 g ha−1 metribuzin treatment and 90% with the water stress regime. Metribuzin at labeled dosing in Saskatchewan induced plant death and considerable vegetative necrosis when evaluated in the greenhouse. • Two weeks after metribuzin treatment, chickpea mortality was 25% for 206 g ai ha−1 dose and 56% for 413 g ha−1 dose. • Chickpea longest branch length was reduced from 34 to 26 cm at 8 WAT with the 206 g ha−1 metribuzin treatment. • Three weeks of water stress reduced chickpea longest branch length from 38 to 24 cm by 8 WAT. • Chickpea pod production was reduced by 75% with the 206 g ha−1 metribuzin treatment and 90% with the water stress regime. [ABSTRACT FROM AUTHOR]

UV/chlorine dioxide (ClO 2) process can be intentionally or accidently conducted and is potentially effective in micro-pollutants degradation. UV irradiation can promote ClO 2 decay and subsequently result in the formation of reactive radicals. Hence, the co-exposure of ClO 2 and UV exhibited a synergetic effect on metribuzin (MET) degradation. The MET degradation was promoted by UV/ClO 2 with a rate of 0.089 min−1 at pH 7.5, which was around 2.4 folds the total of rates caused by single ClO 2 (0.004 min−1) and single UV (0.033 min−1). Reactive radicals mainly HO• and reactive chlorine species were involved in the acceleration effect, and contributed to 59%–67% of the total degradation rate of MET during UV/ClO 2 under pHs 5.5–7.5. Among them, HO• was the predominant contributor and the contribution rate gradually rose under higher pH. Chlorite (ClO 2 −) and chlorate (ClO 3 −) formation has been the major concern of ClO 2 oxidation. However, a comparison of their formation during UV/ClO 2 and ClO 2 oxidation is rarely reported. Herein, during MET degradation by ClO 2 , only ClO 2 − was identified with the highest amount of 1.17 mg L−1. Conversely, during MET degradation by UV/ClO 2 , only ClO 3 − was identified with the highest amount of 0.68 mg L−1, showing an upward trend with prolonging treatment time. Furthermore, organic halogenated DBPs formation after 24 h post-chlorination with UV/ClO 2 and ClO 2 pre-treatments was comparatively evaluated. Organic DBPs formation after post-chlorination was higher with UV/ClO 2 pre-treatment compared to ClO 2 pre-treatment. The overall concentration of DBPs produced with 30 min UV/ClO 2 pre-treatment was about 4.5 times that with 1min UV/ClO 2 pre-treatment. This study provided useful reference for the application of UV/ClO 2 in micro-pollutants degradation. [Display omitted] • UV/ClO 2 accelerated metribuzin degradation by a factor of 2.4 at pH 7.5. • HO• contributed to 20%–46% of total metribuzin removal in UV/ClO 2 at pHs 5.5–8.5. • Natural organic matter, HCO 3 −, and Cl− inhibited metribuzin degradation by UV/ClO 2. • UV/ClO 2 noticeably inhibited chlorite formation but enhanced chlorate formation. • UV/ClO 2 enhanced disinfection by-products formation after 24 h post-chlorination. [ABSTRACT FROM AUTHOR]

• Pesticide contamination is a threat to general public health across the world. • Authors have studied the interaction of GO with through experimental and computational approach. • Change in energy for the complex (GO-pesticides) were found negative and so, the binding is effective. • Binding of pesticides with is confirmed with SEM and powder x-ray diffraction XRD techniques. Pesticides are classified as rodenticides, insecticides, fungicides, and herbicides since they have the potential to kill a variety of pests, such as rodents, insects, fungus, weeds, etc. Due to their specific usage in the agricultural sector to ensure crop output and productivity, pesticide contamination is now one of the most serious threats to general public health across the world. Therefore, the authors thought of finding approaches to remove the pesticides (metribuzin and fipronil) through adsorption with the experimental techniques {scanning electron microscopic (SEM) technique, UV–Visible spectroscopy, powder x-ray diffraction (XRD)} and computational calculations using Gaussian (DFT calculations) and molecular dynamics (MD) simulations. It can be easily understood about the feasibility of the formation of the conjugates (GO-MET and GO-FIP) through adsorption. Therefore, GO could be used as promisng candidate for the removal of metribuzin (MET) and fipronil (FIP). [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A microscale extraction – cleanup method for herbicides from high adsorbent matrixes. • The method efficiently extracts and clean up herbicides from high adsorbent matrixes. • Methodology reduces time, consumables and energy consumption compared to Soxhlet extraction. • Evidence found of presence of 2,4-dichlorophenol, atrazine and desethylatrazine in air samples. • No evidence of metribuzin presence in air samples but retained in soil. In this study, an extraction method was developed, incorporating in-situ sample clean-up and efficient recovery of liquid extracts from high-adsorbent matrices as soil and polymeric resin. The method was based on Ultrasonic Assisted Extraction employing a coupled double tube, with a silica gel disk for interference removal. Subsequent extract recovery was achieved through centrifugation. Optimization of the method was accomplished using a mixed 2- and 3-level factorial experimental design, guided by desirability center on the recovery of four prevalent herbicides (2,4-dichlorophenol, desethylatrazine, Atrazine, and Metribuzin). Under the identified optimal conditions, the method exhibited reduced solvent usage, energy consumption and time requirement in comparison to the reference Soxhlet extraction method. Conducting three consecutive 5-minute extractions utilizing acetone (0.5 mL for soil or 5.0 mL for resin) as the solvent, along with 0.25 g of compacted silica gel for clean-up, yielded recoveries between 84.9 ± 3.1% and 95.2 ± 7.7%. Matrix effect was significant for both soil and resin samples, for soil a signal enhancement up to 12.2% was observed, meanwhile for resin the signals were depleted up to 16.9%. Method calibration curves were employed to account for matrix effect in real samples. Method detection limits ranged from 0.3 to 1.1 ng g−1 for soil samples and from 16.1 to 18.0 ng g−1 for resin samples. The intra- and inter-day precision (RSD) remained under 7.5% for resin samples and below 5.0% for soil samples. Accuracy (bias) values were below 4.4 ± 0.5% and 7.8 ± 1.1% for resin and soil samples, respectively. Application of the method to real samples collected from a potato crop in southern Mexico City revealed herbicides concentrations ranging from 0.02 to 2.94 µg g−1 in soil samples and from 79.7 to 103.3 ng g−1 in resin samples obtained from air sampling. [ABSTRACT FROM AUTHOR]

Field and greenhouse studies investigated the phytoene desaturase (PDS) and photosystem II (PSII)-inhibiting herbicides, norflurazon and metribuzin, as components of two- and three-way postemergence (POST) tank mixtures for controlling multiple herbicide-resistant (MHR) waterhemp (Amaranthus tuberculatus). Studies were conducted at two locations (Champaign County, Illinois, U.S.A (CHR) and McLean County, Illinois, U.S.A. (MCR)) during 2019 and 2020. One of three commercial HPPD-inhibiting herbicides (mesotrione, tembotrione or topramezone) was added to a tank mixture with norflurazon, a reduced rate of metribuzin, or both to determine if greater MHR waterhemp control with tank mixtures could be achieved compared to individual herbicides and assess the potential benefit of norflurazon. Field results indicated the addition of norflurazon to HPPD-inhibiting herbicides resulted in greater waterhemp control (14% increase on average) compared to individual herbicides applied alone. Additionally, metribuzin in combination with HPPD-inhibiting herbicides consistently increased control of MHR waterhemp populations compared to the herbicides applied alone. However, only the three-way tank mixture containing tembotrione at the MCR site reduced biomass relative to two-way treatments containing tembotrione, metribuzin or norflurazon. Greenhouse experiments characterized mixtures of norflurazon with metribuzin and the HPPD-inhibiting herbicides, mesotrione and topramezone. Waterhemp biomass was significantly reduced when metribuzin and HPPD inhibitors were combined in comparison to individual components. Two-way tank mixtures containing norflurazon with mesotrione or metribuzin also resulted in significant biomass reductions compared to herbicides applied alone in MHR waterhemp. However, lower control levels were noted in MHR waterhemp when norflurazon was mixed with either topramezone or topramezone plus metribuzin compared to topramezone alone. In summary, norflurazon and metribuzin can be effective tank mixture components with HPPD-inhibiting herbicides for MHR waterhemp control. However, more research on these tank mixtures is warranted to optimize weed control and crop selectivity, which includes investigating active ingredient ratios, application timings and droplet spectrum effects on coverage. • Multiple herbicide resistance in weeds is an increasing problem in agriculture. • Tank mixtures with herbicides from several site-of-action groups are frequently used. • Tank mixture interactions, such as synergy or antagonism, occasionally occur. • HPPD-inhibiting and PSII-inhibiting herbicides often show synergy on dicot weeds. • Norflurazon exhibited varying interactions with HPPD inhibitor and metribuzin mixes. [ABSTRACT FROM AUTHOR]

A simple and low‐cost method of obtaining slow‐release pesticide formulations is proposed by co‐extrusion of a herbicide metribuzin with a low‐melting biodegradable polyester poly‐ε‐caprolactone, at a temperature above the melting points of both components. Formulations containing 10%, 20%, and 40% herbicide are prepared. Metribuzin release in water during 7 days of exposition reached 81% from the formulations with the 10% loading and 96% from the specimens with the 40% herbicide loading. Biodegradation and pesticide release from the polymer constructs are studied in the model soil for 14 weeks. Degradation rates of the specimens increased with an increase in pesticide content: between 9% for the 10%‐loaded specimen and 20% for the 40%‐loaded specimen over 14 weeks. The release of metribuzin from the specimens with the 10–20% and 40% loadings reached 37–38% and 55%, respectively; thus, taking into account soil degradation of the herbicide, the herbicide content in soil reached 23–25% and 33%, respectively, of the initially loaded into the polymer matrix. The used approach is promising to obtain long‐term release formulations for soil application. [ABSTRACT FROM AUTHOR]

Potato producers in the Atlantic Canadian provinces of New Brunswick (NB) and Prince Edward Island (PE) rely on the photosystem II-inhibiting herbicide metribuzin for weed management. Recently, potato producers in the region have reported unacceptable common lambsquarters control following an application of metribuzin. Tissue and seed samples were collected from escaped common lambsquarters populations from across the potato producing regions of NB and PE and screened for the Ser264Gly mutation in psbA. Overall, 46% of sampled populations possessed the Ser264Gly mutation across the region. Cross-resistance testing to atrazine, metribuzin and linuron confirmed populations with the Ser264Gly were resistant to triazines and triazinones but remained susceptible to linuron. Dose response analysis determined a moderate level of resistance to metribuzin in common lambsquarters which would not be controlled in producers fields. A field experiment was conducted in Fredericton, NB and Harrington, PE, to determine if currently registered and unregistered products and tank-mixes would control PSII-inhibitor-resistant common lambsquarters in potato. All evaluated products, with the exception of S-metolachlor, provided control equivalent to the weed-free check without compromising potato yield or quality. This study demonstrates that PSII-inhibitor-resistant common lambsquarters are found in Atlantic Canadian potato production systems, but can be controlled with currently registered herbicides and rates with alternative modes of action.