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The incidence of volunteer EnlistTM soybean in the post-emergence of crops in succession, such as wheat, requires changes in chemical control. Thus, the objective of the work is to evaluate the efficiency of different post-emergence herbicides in the control of volunteer EnlistTM soybean and wild radish and their selectivity to wheat. For this, four experiments were conducted in 2017 and 2018 in field and greenhouse. The treatments tested were pyroxsulam, saflufenacil, pyroxsulam + saflufenacil, pyroxsulam + bentazon, pyroxsulam + metribuzin, saflufenacil + bentazon, and saflufenacil + metribuzin in 2017, and triclopyr, saflufenacil, MCPA, quinclorac, dicamba, pyroxsulam + metribuzin, metribuzin + metsulfuron, pyroxsulam + bentazon and bentazon + metsulfuron in 2018. The variables were the control of wild radish and volunteer EnlistTM soybean phytotoxicity to wheat crop, yield components, and yield total. The association of the herbicides pyroxsulam and saflufenacil is efficient in the management of volunteer soybean EnlistTM, showing selectivity to wheat. The isolated application of dicamba and the associations of pyroxsulam with metribuzin and metribuzin with metsulfuron represent alternatives for selective management of volunteer EnlistTM soybean in wheat, in addition to efficiently controlling wild radish in post-emergence.

A new idea for the modification of a carboxylic group in phenoxyacetic herbicides is proposed. Common herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA), and their chalcogen analogs (arylthio and arylselenyl fragments instead of a phenoxy one) were used as carboxylic components in the tricomponent Passerini reaction. Cyclohexyl isocyanide and 4-isocyano-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO-NC) were used as isocyanides. Acetone, acetaldehyde and formaldehyde were used as carbonyl components. Passerini adducts 4a–4L were obtained in yields of 32–59%. The structures of the Passerini adducts were determined using spectroscopic methods: MS, HR MS, 1H NMR, 13C NMR, 77Se NMR (if appropriate) and IR spectra (MS, HR MS, IR for the nitroxides 4k and 4L). The herbicidal activity of the Passerini adducts synthesized (4a–4L) was tested against ten weed species (at 2 kg/ha using 2,4-D and MCPA as a control). 100% herbicidal post-emergent activity was reported for 4i, 4j, 4k, 4L [a weed black mustard (Brassica nigra)], for 4k, 4L [weeds pale smartweed (Polygonum lapathifolium) and fathen (Chenopodium album)], as well as for 4k (weeds common poppy (Papaver rhoeas) and gallant soldier (Galinsoga parviflora)). The fungistatic activity of the Passerini adducts synthesized (4a–4L) was tested against six phytopathogenic fungi species (at 200 mg/L and procymidone as a control). The tested compounds showed a weak activity (% of inhibition) against: Alternaria alternata: 4g (47), 4i (26), 4j (26), 4k (50), Botrytis cinerea 4g (38), Fusarium culmorum 4g (44), Phytophthora cactorum 4i (35), 4j (35), 4k (30), Rhizoctonia solani 4g (30), 4i (24), Phytophthora infestans 4g (29), 4i (34), 4j (28), 4k (46).

Bacillus subtilis employs ten chemoreceptors to move in response to chemicals in its environment. While the sensing mechanisms have been determined for many attractants, little is known about the sensing mechanisms for repellents. In this work, we investigated phenol chemotaxis in B. subtilis. Phenol is an attractant at low, micromolar concentrations, and a repellent at high, millimolar concentrations. McpA was found to be the principal chemoreceptor governing the repellent response to phenol and other related aromatic compounds. In addition, the chemoreceptors McpC and HemAT were found to the govern the attractant response to phenol and related compounds. Using receptor chimeras, McpA was found to sense phenol using its signaling domain rather than its sensing domain. These observations were substantiated in vitro, where direct binding of phenol to the signaling domain of McpA was observed using saturation-transfer difference nuclear magnetic resonance. These results further advance our understanding of B. subtilis chemotaxis and demonstrate that the signaling domain of B. subtilis chemoreceptors can directly sense chemoeffectors.IMPORTANCEBacterial chemotaxis is commonly thought to employ a sensing mechanism involving the extracellular sensing domain of chemoreceptors. Some ligands, however, appear to be sensed by the signaling domain. Phenolic compounds, commonly found in soil and root exudates, provide environmental cues for soil microbes like Bacillus subtilis. We show that phenol is sensed both as an attractant and a repellent. While mechanism for sensing phenol as an attractant is still unknown, we found that phenol is sensed as a repellent by the signaling domain of the chemoreceptor McpA. This study furthers our understanding of the unconventional sensing mechanisms employed by the B. subtilis chemotaxis pathway.

In southern Australia, annual sowthistle and prickly lettuce have become more prevalent following the adoption of reduced tillage cropping systems. They are especially problematic in lentil and other pulse crops, which are weakly competitive and have few herbicide options available for POST control of broadleaf weeds. This study aimed to evaluate the influence of management in a previous cereal crop on weed densities in a subsequent crop. At two field sites, crop seeding density and POST herbicide treatments (a conventional choice that included metsulfuron-methyl and MCPA; and a proactive choice that included bromoxynil, picolinafen, and MCPA) were applied to a wheat crop, and weed density was assessed at the beginning of the following season to measure for a legacy effect of the treatments. Study site populations were also screened for herbicide resistance and were found to have high (≥90% survival) ALS inhibitor resistance. Crop competition treatments had no effect on weed populations, and effects of herbicide treatment were significant at only one of the sites. At this site, both herbicide treatments had lower weed densities than the nontreated in the first year, but the legacy effect was only significant for annual sowthistle density in the proactive treatment. At both sites, even where weeds were extremely sparse or completely controlled following herbicide treatment in the first year, moderate densities were observed the following year, indicating that colonization from the seedbank or adjacent areas could be contributing to weed numbers. Weed density assessments and accurate knowledge of the herbicide resistance status of target weeds should guide herbicide selection to maximize control.

Leptospira is a genus of spirochete bacteria highly motile that includes pathogenic species responsible to cause leptospirosis disease. Chemotaxis and motility are required for Leptospira infectivity, pathogenesis, and invasion of bacteria into the host. In prokaryotes, the most common chemoreceptors are methyl-accepting chemotaxis proteins that have a role play to detect the chemical signals and move to a favorable environment for its survival. Here, we report the first crystal structure of CACHE domain of the methyl-accepting chemotaxis protein (McpA) of L. interrogans. The structural analysis showed that McpA adopts similar α/β architecture of several other bacteria chemoreceptors. We also found a typical dimerization interface that appears to be functionally crucial for signal transmission and chemotaxis. In addition to McpA structural analyses, we have identified homologous proteins and conservative functional regions using bioinformatics techniques. These results improve our understanding the relationship between chemoreceptor structures and functions of Leptospira species.

Herbicides such as (3,6-dichloro-2-methoxy)benzoic acid (dicamba), (4-chloro-2-methylphenoxy)acetic acid (MCPA), (2,4-dichlorophenoxy)acetic acid (2,4-D), or (±)-2-(4-chloro-2-methylphenoxy)propion...

The experiment was conducted at Agronomy Field Laboratory of Patuakhali Science and Technology University, Dumki, Patuakhali, Bangladesh from July 2018 to November 2018 to find out the effect of sunflower residues and herbicides on weed control and yield of T. Aman rice. Weed control methods tested were T 1 = weedy check,T 2 = Weed free check, T 3 = Pendimethalin,T 4 = Pretilachlor,T 5 = Butachlor,T 6 = Pyrazosulfuron ethyl,T 7 = Bensulfuron methyl + Acetachlor,T 8 = Bispyriback sodium,T 9 =2,4-D amine,T 10 =MCPA,T 11 = Sunflower residues ,T 12 = Sunflower residues + 100%Pyrazosulfuron ethyl,T 13 = Sunflower residues + 75%Pyrazosulfuron ethyl,T 14 = Sunflower residues + 50%Pyrazosulfuron ethyl. The weed spectrum of the experimental field consisted of all the three groups of weeds viz., grasses (15.78%), sedges (59.02%) and broad-leaved weeds (25.2%). The dominants weeds were Cynodon dactylon and Echinochloa crusgalli among grasses; Cyperus difformis , Fimbristylis miliacea and Scirpus supinus among sedges and Jussiaea decurrens among broad-leaved weeds. Hand weeding recorded the highest weed control efficiency (99.05%) and weedy check recorded the lowest. Among different herbicides applied alone, butachlor had the highest weed control efficiency (87.59%).Hand weeding produced the highest grain yield (5.14 t ha -1 ) which was statistically similar to butachlor, pendimethalin, pretilachlor, bensulfuron methyl + acetachlor and sunflower residues + 100% pyrazosulfuronethyl. Application of sunflower residues along with the reduced rate (75 or 50%) of pyrazosulfuron ethyl had effective weed control and satisfactory yield comparable to butachlor. The farmers can use this technology as an eco-friendly approach in transplanted Aman rice field.

Herbicide dose-responses of seedling progenies of Ranunculus acris populations varying in herbicide exposure history indicate that this weed has evolved multiple resistance to phenoxycarboxylic aci...

Common blue violet is a widely distributed, perennial broadleaf that is difficult to control in lawns. Two experiments were conducted to evaluate the efficacy of synthetic auxin herbicides and their mixtures or rate for common blue violet control. A herbicide comparison experiment was conducted with treatments including a nontreated check; 2,4-D dimethylamine; 2,4-D isooctyl ester (2,4-D ester); dichlorprop (2,4-DP) ethylhexyl ester, MCPA dimethylamine; mecoprop dimethylamine; triclopyr butoxyethyl ester; quinclorac; and mixtures of triclopyr + quinclorac; 2,4-D ester + 2,4-DP; 2,4-D ester + triclopyr; 2,4-D ester + 2,4-DP + triclopyr. All herbicides were applied at 1.12 kg ae ha–1 except quinclorac (0.84 kg ha–1). Additionally, a triclopyr dose-response experiment was conducted using rates of 0, 0.14, 0.28, 0.56, 0.84, and 1.12 kg ha–1. Epinasty ranged from 80% to 99% at 21 d after application for triclopyr-containing treatments and no more than 28% for all other treatments. Plant mass from harvest and regrowth data from the comparison experiment indicated triclopyr-containing treatments provided the highest common blue violet control. Mixtures containing triclopyr did not differ from triclopyr alone, indicating there was no added effect between herbicide mixtures. The triclopyr dose-response experiment confirmed triclopyr efficacy across data collection types. As triclopyr dose increased, violet epinasty increased and chlorophyll content and dry weight decreased. Triclopyr applied at 0.81 kg ha–1 or greater concentration provided 75% or greater control, as indicated by regrowth data. Many herbicides containing triclopyr are registered for use in turf, but most apply a concentration not greater than 0.56 kg ha–1 triclopyr when applied at the high label rate. Thus, to achieve good (75%) common blue violet control, turf managers should select products that contain triclopyr and apply doses of at least 0.81 kg ha–1 when used according to the label.Nomenclature: 2, 4-dichlorophenoxyacetic acid; (±)-2-(4-chloro-2-methylphenoxy)propanoic acid (mecoprop); (±)-2-(2, 4-dichlorophenoxy) propanoic acid (dichlorprop); 2, 4-D dimethylamine; 2, 4-D isooctyl ester; 4-chloro-2-methylphenoxyacetic acid; 3, 7-dichloro-8-quinolinecarboxylic acid (quinclorac); 3, 5, 6-trichloro-2-pyridinyloxyacetic acid (triclopyr); common blue violet; Viola sororia Willd. VIOPP.

One side effect of human activity and global climatic change is more airborne dust. This not only has undesirable effects on human health and the environment, but may also adversely affect many agricultural processes, including herbicide efficacy. This is particularly relevant in parts of the world where dust storms are common and limited rainfall means dust persists on plants for protracted periods. Accordingly, a series of greenhouse dose–response pot experiments was carried out to quantify the effect of a dust concentration of 1,500 µg/m³ on the performance of paraquat, glyphosate, sulfosulfuron and 2,4‐D+MCPA. Dust‐treated and untreated seedlings of Hordeum spontaneum and Sinapis arvensis were sprayed with sulfosulfuron and 2,4‐D+MCPA, respectively, while paraquat and glyphosate were applied to both weed species. The efficacy of glyphosate and paraquat decreased significantly in the presence of dust on both species. Similar results were observed for 2,4‐D+MCPA on S. arvensis. In contrast, the efficacy of sulfosulfuron on H. spontaneum was not affected by dust. In the presence of dust, the doses of glyphosate, paraquat and 2,4‐D+MCPA required for a 90% effect were enhanced by a factor of 1.9 to 2.6. The negative impact on glyphosate efficacy was more pronounced in S. arvensis than H. spontaneum, while it was similar for paraquat. Future studies should consider the amount, duration and composition of dust as well as its impact on other weeds and herbicides. Potential approaches to overcome the detrimental influence of dust on the performance of herbicides were also suggested for future studies.

Horseweed is a competitive summer or winter annual weed that produces up to 230,000 small seeds per plant that are capable of traveling more than 500 km via wind. Giant ragweed is a tall, highly competitive summer annual weed. Glyphosate-resistant (GR) horseweed and GR giant ragweed pose significant challenges for producers in the United States and Ontario, Canada. It is thought that an integrated weed management (IWM) system involving herbicide rotation is required to control GR biotypes. Halauxifen-methyl is a new selective broadleaf POST herbicide registered for use in cereal crops; there is limited information on its efficacy on horseweed and giant ragweed. The purpose of this research was to determine the efficacy of halauxifen-methyl applied POST, alone and in a tank mix, for the control of GR horseweed and GR giant ragweed in wheat across southwestern Ontario. For each weed species, an efficacy study consisting of six field experiments was conducted over a 2-yr period (2018, 2019). At 8 wk after application (WAA), halauxifen-methyl, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, 2,4-D ester, clopyralid, and pyrasulfotole/bromoxynil + ammonium sulfate controlled GR horseweed >95%. Fluroxypyr and MCPA provided only 86% and 37% control of GR horseweed, respectively. At 8 WAA, fluroxypyr, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, fluroxypyr/halauxifen-methyl + MCPA EHE + pyroxsulam, 2,4-D ester, clopyralid, and thifensulfuron/tribenuron + fluroxypyr + MCPA ester controlled GR giant ragweed 87%, 88%, 90%, 94%, 96%, 96%, 98%, and 93%, respectively. Halauxifen-methyl and pyroxsulam provided only 45% and 28% control of GR giant ragweed, respectively. Halauxifen-methyl applied alone POST in the spring controlled GR horseweed but not GR giant ragweed in winter wheat.

Parthenium hysterophorus L. (parthenium weed) is an annual weed that grows rapidly in disturbed land. It is considered as one of the most hazardous weeds in Pakistan as it poses serious health problems to livestock as well as severe allergenic reactions in humans. It has invaded the Punjab and Khyber Pakhtunkhwa provinces and also been spreading in other parts of the country where it poses a risk for the grazing lands, roadsides, forests, wet lands, waste lands and of all types of cropped and non-cropped areas in Pakistan. The present studies were carried out to determine the impact of four locally available broad leaf herbicides viz; Stomp 455 CS (pendimethalin), Buctril Super 60 EC (bromoxynil + MCPA), Vantage 48 SL (glyphosate) and Logran Extra 750 WG (triasulfuron + terbutryn) (@ recommended and ½ of recommended dose) against P. hysterophorus grown in pots at research field of CABI CWA, Rawalpindi. All herbicides were applied at three growth stages (rosette, bolted and flowering). The observations for the mortality of P. hysterophorus were made 2 and 4 weeks after spray. The glyphosate was the most effective and reported 100% mortality of P. hysterophorus plants at flowering stage followed by bromoxynil + MCPA (89%), pendimethalin (80%) and triasulfuron + terbutryn (61%) at recommended dose after 4 weeks of spray. All tested herbicides achieved a mortality between 38% - 86% at rosette while 54% - 96% mortality at bolted stage after 4 weeks. Initially, 2 weeks after spray at flowering stage glyphosate caused 53% wilting followed by 49% (bromoxynil + MCPA), 33% (pendimethalin) and 9% (triasulfuron + terbutryn) at their recommended doses. The results indicated that P. hysterophorus is the most susceptible to glyphosate and bromoxynil + MCPA, both these herbicides are very promising for the wilting and management of parthenium weed.

Glyphosate-based foliar spray herbicides are the most common method for urban weed control due to their broad-spectrum and efficacy for burndown applications. As interest in glyphosate alternatives has increased in recent years, this project assessed the efficacy of the following non-glyphosate-based alternative weed management strategies: glufosinate, imazapyr, MCPA + dicamba, prodiamine, pine oil, clove oil, nonanoic acid, acetic acid + hydrochloric acid and steam against untreated (negative) controls and glyphosate-treated sites. Across all four seasonal treatments (winter, spring, summer and autumn), glyphosate and glufosinate reduced weed coverage (&gt, 65% after 4 and 12 weeks), imazapyr reduced weed coverage by &gt, 80% after 12 weeks, and steam reduced weed coverage by &gt, 80% after 4 weeks, and after 12 weeks showed to reduce weed coverage by &gt, 20% after the second application. The MCPA + dicamba, prodiamine, pine oil, clove oil, nonanoic acid and acetic acid + hydrochloric acid treatments had mixed impacts on weed coverage. Minimal alterations to soil physicochemical properties were observed across the two sites for all treatments. Assessment of impacts the different weed management strategies had on arthropod and microbial relative abundance showed minimal alterations, with only steam observed to reduce relative microbial abundance. Glufosinate, imazapyr and steam may be considered alternatives to glyphosate for reducing weed coverage but may not be as effective or have undesirable off-target effects. Overall, glyphosate provided the most consistent weed reduction at both sites over 12 weeks, without any recorded negative off-target or soil biota impacts.

International audience; Atypical myopathy (AM) is a severe rhabdomyolysis syndrome that occurs in grazing horses. Despite the presence of toxins in their blood, all horses from the same pasture are not prone to display clinical signs of AM. The objective of this study was to compare the blood metabolomic profiles of horses with AM clinical signs with those of healthy co-grazing (Co-G) horses. To do so, plasma samples from 5 AM horses and 11 Co-G horses were investigated using untargeted metabolomics. Metabolomic data were evaluated using unsupervised, supervised, and pathway analyses. Unsupervised principal component analysis performed with all detected features separated AM and healthy Co-G horses. Supervised analyses had identified 1276 features showing differential expression between both groups. Among them, 46 metabolites, belonging predominantly to the fatty acid, fatty ester, and amino acid chemical classes, were identified by standard comparison. Fatty acids, unsaturated fatty acids, organic dicarboxylic acids, and fatty esters were detected with higher intensities in AM horses in link with the toxins' pathological mechanism. The main relevant pathways were lipid metabolism; valine, leucine, and isoleucine metabolism; and glycine metabolism. This study revealed characteristic metabolite changes in the plasma of clinically affected horses, which might ultimately help scientists and field veterinarians to detect and manage AM. The raw data of metabolomics are available in the MetaboLights database with the access number MTBLS2579.

Chemotaxis towards root exudates and subsequent biofilm formation are very important for root colonization and for providing the beneficial functions of plant growth-promoting rhizobacteria (PGPRs). In this study, in comparison with other root-secreted compounds, D-galactose in the root exudates of cucumber was found to be a strong chemoattractant at the concentration of 1 μM for Bacillus velezensis SQR9. Chemotaxis assays with methyl-accepting chemotaxis proteins (MCPs) deletion strains demonstrated that McpA was solely responsible for chemotaxis towards D-galactose. Interestingly, D-galactose significantly enhanced the biofilm formation of SQR9 in an McpA-dependent manner. Further experiment showed that D-galactose also enhanced root colonization by SQR9. In addition, the secretion of D-galactose by cucumber roots could be induced by inoculation with SQR9, indicating that D-galactose may be an important signal in the interaction between plant and SQR9. These findings suggested that the root-secreted D-galactose was a signal, the secretion of which was induced by the beneficial bacteria, and which in turn induced colonization of the bacteria.

2-Methyl-4-chlorophenoxyacetic acid has been widely used as herbicide in the United States and Europe. This study aims to quantify its effects at concentrations of 0–100 mg/L for up to 48 h on the ...

A field study was conducted to evaluate the compatibility of herbicide tank mixtures in winter wheat (Triticum aestivum L.) Sagittario cv. in 2017-2019. Weed Index (VI) and Crop Injury (CI) of three mixtures prominent was recorded with mesosulfuron-methyl plus 2.4-D ethylhexyl ester + florasulam (5.8% and 1.5%) followed by pyroxsulam + florasulam + cloquintocet-mexyl plus 2.4-D dimethylamine salt (6.3% and 1.6%), and mesosulfuron-methyl + iodosulfuron-methyl-sodium plus bromoxynil + MCPA (7.1% and 0.0%), respectively. Weed Control Efficiency (WCE) was maximum with mesosulfuron-methyl + mefenpyr-diethyl plus 2.4-D ethylhexyl ester + florasulam so, Cirsium arvense (90%) heavily damaged; Avena fatua (98%), Avena sterilis (94%), and Papaver rhoeas (96%), Sinapis arvensis (95%) very heavy damaged (severe chlorosis and/or dead leaves); Galium aparine, Phalaris brachystachys, and Ranunculus arvensis were completely killed (100%, dead). Consequently, mesosulfuron-methyl + mefenpyr-diethyl plus 2.4-D ethylhexyl ester + florasulam herbicide mixture is recommended to provide weed control efficiency and wheat production safely. The compatibility of herbicides is necessary for sustainable weed management as it leads to reduced input costs, to prevent economic losses and to less pollution of the ecological environment. In addition, the conditions may require that the herbicides be applied with fungicides, insecticides or foliar fertilizers, and growers wish to know the safety of these mixtures. Therefore, studies on the compatibility of chemicals used in agriculture were considered to be needed.

The adoption of chemical fallow rotations in Pacific Northwest dryland winter wheat production has caused a weed species composition shift in which scouringrush has established in production fields. Thus, there has been interest in identifying herbicides that effectively control scouringrush in winter wheat–chemical fallow cropping systems. Field experiments were established in growers’ fields near Reardan, WA, in 2014, and The Dalles, OR, in 2015. Ten herbicide treatments were applied to mowed and nonmowed plots during chemical fallow rotations. Scouringrush stem densities were quantified the following spring and after wheat harvest at both locations. Chlorsulfuron plus MCPA-ester resulted in nearly 100% control of scouringrush through wheat harvest. Before herbicide application, mowing had no effect on herbicide efficacy. We conclude chlorsulfuron plus MCPA-ester is a commercially acceptable treatment for smooth and intermediate scouringrush control in winter wheat–chemical fallow cropping systems; however, the lack of a positive yield response when scouringrushes were controlled should factor into management decisions.

Controlling Asphodelus tenuifolius in chickpea crop is a big challenge for the grower in the southern districts of Khyber Pakhtunkhwa-Pakistan. Keeping in view the yield losses due to weeds a research was conducted at Ahmadwala Research Station “District Karak” to control to A. tenuifolius. Herbicides, mulches and allelopathic weed extracts were evaluated during the experiment. The experiment was repeated thrice using Randomized Complete Block design with Chattan cultivar. The weed control treatments Viz. Stomp 330 EC (Pre) @ 2.5 L ha−1, Fenoxaprop-p-ethyl, Bromoxynil +MCPA (Tank mixture of herbicides), Starane-M, Eucalyptus leaves as mulch, wheat straw as mulch, allelopathic extract (Asphodelus tenuifolius) + Stomp, allelopathic Cyperus rotundus extract, allelopathic Sorghum halepense extract were tested and compare with the control treatment during the experiment. The data was recorded on A. tenuifolius density m−2 before and after treatment application, plant height, crude protein, crude fats, biological yield, and seed yield. The level of significance of all the treatments was (0.05). The results indicated that the minimum A. tenuifolius density was recorded in the plots treated with Stomp 330 EC (4.74 m−2) followed by herbicide Fenoxaprop-p-ethyl 6.9 EC (10.87 m−2). The maximum A. tenuifolius density was found in the control plots (81.64 m−2) which were left undisturbed. Among the chickpea yield components, the maximum plant height at maturity (48.98 cm) was recorded for Stomp 330 EC the lowest plant height was recorded for control plot. The maximum crude protein (17.68), crude fat (2.93) and oil content was (5.92%) was recorded in the plots treated with Stomp 330 EC and the minimum was found in the control plots. Similarly, the maximum biological yield (4058.7 kg ha−1) and seed yield (1282 kg ha−1) were recorded in Stomp 330 EC treated plots as biological and grain yield was observed for control plot. Therefore, it is recommended that using herbicides Stomp 330 EC and Fenoxaprop-p-ethyl is one of the effective weed control strategies for control of A. tenuifolius in chickpea growing areas.

Background and Aims Spring drift of herbicides can have devastating consequences on grapevines. The impact of 2,4‐dichlorophenoxyacetic acid (2,4‐D), dichloro‐2‐methoxybenzoic acid (Dicamba), 2‐methyl‐4‐chlorophenoxyacetic acid (MCPA) and glyphosate exposure on reproductive and vegetative development was investigated. Methods and Results Simulated herbicide drifts were applied to potted vines at the cessation of flowering. Leaf gas exchange and biomass, root structural biomass and carbohydrate reserves, fruit yield and compound bud necrosis were assessed, along with berry composition, including the primary metabolites, at fruit maturity. Fruit yield was reduced by 2,4‐D without any detriment to most aspects of berry composition. While root structural development was curtailed by 2,4‐D, Dicamba and MCPA, none of the herbicides altered the reserve level of root total non‐structural carbohydrates. Primary bud necrosis was evident following 2,4‐D and Dicamba exposure, especially in younger buds. Conclusions Exposure to 2,4‐D may be particularly damaging to fruit yield during the current season because of an increased risk of bunch necrosis. Bud fruitfulness can be impaired by 2,4‐D and Dicamba because of the increased potential for primary bud necrosis. Significance of the Study Auxin‐type herbicides can limit fruit yield during the current and next season. Compared to cane pruning, spur pruning may minimise the detrimental effects of these herbicides on fruitfulness.

A quick test to enable early detection of flumetsulam and MCPA resistance in Ranunculus acris L. subsp. acris was developed in a series of Petri dish assays and pot trials. Initial experiments used...

Flax yield can be severely reduced by weeds. The combination of limited herbicide options and the spread of herbicide-resistant weeds across the prairies has resulted in a need for more weed control options for flax producers. The objective of this research was to evaluate the tolerance of flax to topramezone, pyroxasulfone, flumioxazin, and fluthiacet-methyl applied alone as well as in a mix with currently registered herbicides. These herbicides were applied alone and in mixtures at the 1X and 2X rates and compared with three industry standards and one nontreated control. This experiment was conducted at Carman, MB, and Saskatoon, SK, as a randomized complete block with four replications. Data were collected for crop population, crop height, yield, and thousand-seed weight. Ratings for crop damage (phytotoxicity) were also taken at three separate time intervals: 7 to 14, 21 to 28, and 56+ d after treatment. Crop tolerance to these herbicides varied between site-years. This was largely attributed to differences in spring moisture conditions and the differences in soil characteristics between sites. Herbicide injury was transient. Hence, no herbicide or combination of herbicides significantly impacted crop yield consistently. Flumioxazin was the least promising herbicide evaluated, as it caused severe crop damage (>90%) when conditions were conducive. Overall, flax had excellent tolerance to fluthiacet-methyl, pyroxasulfone, and topramezone. Flax had excellent crop safety to the combination of pyroxasulfone + sulfentrazone. However, mixing fluthiacet-methyl and topramezone with MCPA and bromoxynil, respectively, increased crop damage and would not be recommended.

Using X. laevis oocyte expression system, we investigated whether human Na+-coupled monocarboxylate transporter 1 (SLC5A8, hSMCT1) is involved in 2,4-dichlorophenoxyacetate (2,4-D) uptake by the renal tubular epithelial cells. 2,4-D is a herbicide that causes nephrotoxicity. Heterologous expression of hSMCT1 in X. laevis oocytes conferred the ability to take up 2,4-D; the induced uptake process was Na+-dependent and electrogenic. The Na+-dependent uptake of 2,4-D was inhibited not only by known hSMCT1 substrates, but also by many structural analogs of 2,4-D. The currents induced by 2,4-D, 4-chlorophenoxyacetate (4-CPA) and 2-methyl-4-chlorophenoxyacetate (MCPA) were saturable: the rank order of the maximal induced current and the affinity for hSMCT1was 2,4-D > 4-CPA > MCPA. The relationship between the structures of the derivatives and their transport activity implied specific structural features in a compound for recognition as a substrate by hSMCT1. Furthermore, we have demonstrated using purified rabbit renal brush-border membrane vesicles that 2,4-D potently inhibited the Na+-dependent uptake of pyroglutamate, a typical substrate for Smct1, and that 2,4-D uptake process was Na+-dependent, saturable and inhibitable by a potent blocker, ibuprofen. We conclude that hSMCT1 is involved partially in the renal reabsorption of 2,4-D and its derivatives and their nephrotoxicity.

The use of a herbicide in Denmark prerequires approval for its use and for the product label by the National Agency of Environmental Protection. The soil-acting herbicides simazine, terbuthylazine, diuron and dichlobenil are, at present, approved for the control of germinating dicotyledonous weeds. Propyzamide is likewise approved, especially for the control of grass weeds. The above mentioned chemicals must be used before the fruit bushes come into flowering. For the control of weeds, post emergent, a few foliage-applied herbicides are approved and are, as yet, permitted for use throughout the growing season, however, this necessitates screened spraying. The contact herbicides paraquat and diquat are used most frequently, both as a mixture with soil herbicides and for burning off weeds throughout the growing season. The translocated herbicides of the phenoxy acid group can also be used throughout the growing season, as long as they are in the form of amine salts. MCPA is used the most, especially for the control of Convolvulus and Equisetum spp, but it may also be used to control Cirsium arvense. 2,4-D is occasionally used instead of MCPA especially if the weed population contains Cirsium and other members of the compositae family. Urtica dioica and Galium spp., are normally controlled by mechlorprop, while dichlorprop is more suitable suitable for the control of Polygonum spp, especially P. amphibium.

Background Water hyacinth (Eichhornia crassipes) is considered as the most damaging aquatic weed in many countries. Chemical methods are still the primary approach for their control, although this directly exposes the natural enemy of water hyacinth (water hyacinth weevil) to herbicides. Additionally, spray-drift can easily damage non-target plants. In this study, herbicides, natural polymer materials (chitosan and carboxymethyl chitosan), sodium alginate, and natural oils (citronella oil) were used to prepare a novel polysaccharide granules with floating characteristics as a solution for controlling water hyacinth. Results MCPA floating granules with a spherical structure were prepared by the MCPA-chitosan-sodium alginate-oil cross-linking and embedding method. The granules produced exhibited suitable floating properties and slow, controlled release of an herbicide. Additionally, the polysaccharide granules gathered around the water hyacinths and targeted the release of active herbicide ingredients onto the stems and roots of the weed, thereby preventing the herbicide from drifting to non-target plants and preventing regrowth of water hyacinth. Conclusion We successfully prepared highly effective MCPA-loaded floating granules. Compared with that by an MCPA solution, our MCPA-containing granules exerted greater control on water hyacinth. Concomitantly, these granules provide a solution to spray-drift and ensure the safety of the natural enemies of water hyacinth, which is of great significance to research on herbicide formulations. This article is protected by copyright. All rights reserved.

To mitigate environmental pollution and food contamination caused by inappropriate and excessive herbicide usage, most potent herbicides should be screened to control rice weeds. A research trial was executed for assessing the comparative efficacy of different herbicides to control rice field weeds and to evaluate the toxicity on rice under normal (distilled water) as well as different salinity levels (4 and 8 dS m−1). The study was designed to select the most potent herbicide and its appropriate dose for weed control of rice crop in coastal areas. Fourteen herbicidal treatments were included weed free crop, Pretilachlor (0.25, 0.50, 0.375 and 0.75 kg a.i. ha−1), Propanil + Thiobencarb (0.6 + 1.2, 0.9 + 1.8, 1.2 + 2.4 and 1.8 + 3.6 kg a.i. ha−1), Bensulfuron + MCPA (0.03 + 0.05, 0.045 + 0.075, 0.06 + 0.1 and 0.09 + 0.15 kg a.i. ha−1) and weedy check (control). The results revealed that all tested herbicides in higher than recommended doses for non-saline rice fields were effective in controlling Cyperus iria, Echinochloa colona (salt-tolerant) and Jussiaea linifolia but showed in light injury in rice plants grown in non-saline soils. These higher doses of herbicides recorded severe crop injury under saline conditions indicating their differential efficacy from normal non-saline conditions. Treatments including Pretilachlor (0.375kg a.i. ha−1), Propanil + Thiobencarb (0.9 + 1.8 kg ai/ha), Bensulfuron + MCPA (0.06 + 0.1 kg a.i. ha−1) and Pretilachlor (0.50 kg a.i. ha−1) remained superior in terms of weed control and grain yield production under all salinitylevels at TanjungKarang, Malaysia. It is concluded that herbicides respond differently under saline conditions and optimization of their doses potentially prevent herbicidal injury in rice plants.

The development of biofilms on modified natural zeolites was investigated with purpose to obtain biocomposites with biodegradation activity towards pesticides MCPA (2-methyl-4-chlorophenoxyacetic acid) and glyphosate (N-(phosphonomethyl)glycine) for potential application in bioaugmentation of polluted agricultural soils. Microbial communities were selected from agricultural pesticide-contaminated soil/water samples and enriched on the basis of their ability to biodegrade the pesticides. In order to enhance affinity of microbial communities to the support material, the natural mineral zeolite was modified by nontoxic environmentally friendly cations (Li+, Na+, K+, NH4+, H+, Mg2+, Ca2+, Fe3+) by methods preserving its structure and characterised using powder XRD, surface area measurement and chemical composition analysis. Kinetics of pesticide degradation by the biocomposites was studied in liquid media. Results showed that according to zeolite modifications, the microbial activity and biodiversity changed. The best biodegradation rate of MCPA and glyphosate reached 0.12-0.13 mg/h with half-life of 16-18 h, which is considerably quicker than observed in natural environment. However, in some cases, biodegradation activity towards pesticides was lost which was connected to unfavourable zeolite modification and accumulation of toxic metabolites. High-throughput sequencing on the 16S rRNA genes of the biofilm communities highlighted the selection of bacteria genera known to metabolise MCPA (Aminobacter, Cupriavidus, Novosphingobium, Pseudomonas, Rhodococcus, Sphingobium and Sphingopyxis) and glyphosate (Pseudomonas). Altogether, results suggested that zeolites do not only have a passive role of biofilm support but also have protective and nutrient-supportive functions that consequently increase biodiversity of the pesticide degraders growing in the biofilm and influence the pesticide biodegradation rate. Byl zkoumán vývoj biofilmů na modifikovaných přírodních zeolitech za účelem získání biokompozitů s biodegradační aktivitou vůči pesticidům MCPA (2-methyl-4-chlorofenoxyoctová kyselina) a glyfosátu (N-(fosfonomethyl)glycin) pro potenciální aplikaci v bioaugmentaci znečištěných zemědělských půd. Mikrobiální společenstva byla vybrána ze vzorků půdy/vody kontaminované zemědělskými pesticidy a obohacena na základě jejich schopnosti biodegradovat pesticidy. Pro zvýšení afinity mikrobiálních společenstev k nosnému materiálu byl přírodní minerální zeolit modifikován netoxickými ekologicky šetrnými kationty (Li+, Na+, K+, NH4+, H+, Mg2+, Ca2+, Fe3+) metodami zachovávajícími jeho strukturu a charakterizován pomocí práškové XRD analýzy, měření měrného povrchu a analýzy chemického složení. Kinetika degradace pesticidů biokompozity byla studována v kapalných médiích. Výsledky ukázaly, že podle modifikací zeolitu se měnila i mikrobiální aktivita a biodiverzita. Nejlepší biodegradační rychlost MCPA a glyfosátu dosáhla 0,12-0,13 mg/h s poločasem rozpadu 16-18 h, což je podstatně rychleji, než je pozorováno v přirozeném prostředí. V některých případech však došlo ke ztrátě biodegradační aktivity vůči pesticidům, což souviselo s nepříznivou modifikací zeolitu a akumulací toxických metabolitů. Vysoce výkonné sekvenování na genech 16S rRNA biofilmových komunit zdůraznilo výběr rodů bakterií, o kterých je známo, že metabolizují MCPA (Aminobacter, Cupriavidus, Novosphingobium, Pseudomonas, Rhodococcus, Sphingobium a Sphingopyxis) a glyfosát (Pseudomonasate). Celkově výsledky naznačují, že zeolit nemá pouze pasivní roli podpory biofilmu, ale má také ochranné a nutričně podpůrné funkce, které následně zvyšují biologickou rozmanitost degradátorů pesticidů rostoucích v biofilmu a ovlivňují rychlost biodegradace pesticidů.

The amount of maize yield depends on many factors. Among them, plant health plays a significant role. Herbicide selectivity (of mesotrione, 2,4-D, and bromoxynil) for different maize varieties was assessed in greenhouse experiments. The effectiveness of herbicides (MCPA, 2,4-D + dicamba) and spraying mixture of the herbicide MCPA with mepiquat chloride was tested on Chenopodium album L. and self-seeding winter oilseed rape (Brassica napus L.). The genetic distance between selected maize varieties and species composition of pathogens of the genus Fusarium isolated from the seeds of the discussed crop were examined. Research results indicated that individual herbicides differed in the selectivity in relation to maize, which depended on the crop variety. The selected herbicides showed high efficacy against the plants used in the experiment. The addition of mepiquat chloride to the composition of the spraying liquid did not affect the level of weed control. No relationship was found between the genetic distance of maize varieties and their sensitivity to selected herbicides. The presence of Fusarium subglutinans, Fusarium proliferatum, and Fusarium verticillioides was found in the samples of maize varieties.

We investigated pH taxis in Bacillus subtilis. This bacterium was found to perform bidirectional taxis in response to external pH gradients, enabling it to preferentially migrate to neutral environments. We next investigated the chemoreceptors involved in sensing pH gradients. We identified four chemoreceptors involved in sensing pH: McpA and TlpA for sensing acidic environments and McpB and TlpB for sensing alkaline ones. In addition, TlpA was found to also weakly sense alkaline environments. By analyzing chimeras between McpA and TlpB, the principal acid- and base-sensing chemoreceptors, we identified four critical amino acid residues—Thr(199), Gln(200), His(273), and Glu(274) on McpA and Lys(199), Glu(200), Gln(273), and Asp(274) on TlpB—involved in sensing pH. Swapping these four residues between McpA and TlpB converted the former into a base receptor and the latter into an acid receptor. Based on the results, we propose that disruption of hydrogen bonding between the adjacent residues upon pH changes induces signaling. Collectively, our results further our understanding of chemotaxis in B. subtilis and provide a new model for pH sensing in bacteria. IMPORTANCE Many bacteria can sense the pH in their environment and then use this information to direct their movement toward more favorable locations. In this study, we investigated the pH sensing mechanism in Bacillus subtilis. This bacterium preferentially migrates to neutral environments. It employs four chemoreceptors to sense pH. Two are involved in sensing acidic environments, and two are involved in sensing alkaline ones. To identify the mechanism for pH sensing, we constructed receptor chimeras of acid- and base-sensing chemoreceptors. By analyzing the responses of these chimeric receptors, we were able to identify four critical amino acid residues involved in pH sensing and propose a model for the pH sensing mechanism in B. subtilis.

The study is based on data from a long-term field experiment of extent and duration seldom found in weed science. Yield losses from weed infestation of individual crops and crop rotations were studied in a field trial conducted since 1972 at two sites in the Czech Republic. The ongoing trial comprises multi-crop and simple crop rotations with 50 and 75% cereals, respectively. Three herbicide treatments were used: (1) untreated; (2) synthetic auxins (MCPA; 2,4-D; only in simple crop rotation) and (3) targeted herbicide combinations, including sulfonylureas, triazines, ureas, and synthetic auxins. Crop yields and weather data were recorded during the trial period and the effects of herbicide application on yield were determined for crop rotation. Yield losses in untreated controls increased in the following order: spring barley

Chlorophenoxyacetic herbicides such as 4-chloro-2-methylphenoxyacetic acid (MCPA) and 2,4-dichlorophenoxyacetic acid (2,4-D) are used for cereal protection. However, some of them penetrate the tissues of protected plants and also get in contact with cereal pathogens. The up-to-date studies concerned their effectiveness in combating the weeds without paying attention to the herbivores occurring in cereal agrocenoses. Therefore, the aim of the present study was to determine the effect of chlorophenoxyacetic herbicides on the probing behavior of grain aphid, Sitobion avenae (F.), bird cherry-oat aphid, Rhopalosiphum padi (L.) and rose-grain aphid, Metopolophium dirhodum (Walk.). The experiment was carried out on wingless females feeding on winter wheat seedlings of Tonacja cv. using the electronic penetration graph (EPG) method. Tested herbicide preparations exerted an influence on the probing behavior of all aphids examined. The inhibitory effect of MCPA and 2,4-D on the uptake of phloem juice was found. It has been shown that chlorophenoxyacetic herbicides are not only effective in combating the weeds of cereal crops, but can also have positive side-effects in the form of limiting the cereal aphids population.

The aim of this study is to assess control effects of 2-methyl-4-chlorophenoxyacetic acid (MCPA) dosage, application timing and crop presence on the weed Cirsium arvense. Swedish farmers are recomm...

Cereal cultivation, mainly of wheat (Triticum aestivum L.) and maize (Zea mays L.), occupies a large area in Moghan Plain, Iran, with frequent use of pesticides, but research pertaining to pesticide use and farmers' attitudes in the area is scarce. The main objective of the present study was to analyze farmers' knowledge of pesticide hazards and use of information sources regarding pesticide use in cereal production in Moghan Plain in northwestern Iran for better understanding what drives farmers' attitudes in pesticide use. To this end, a survey of 400 farmers was conducted. Pesticide use mainly concerned the most common herbicides used in cereal production in the area (2,4-D and MCPA), the most common fungicides used in wheat (mancozeb and propiconazole), and the most common insecticides used in maize (indoxacarb and chlorpyrifos). The surveyed farmers appeared divided, with almost half (49.2%) having rather negative attitude towards pesticide use and the other half (50.8%) exhibiting rather positive attitude. Experienced farmers and farmers with large cultivated land showed more positive attitude towards pesticide use. More than half of the farmers (53.0%) had rather weak knowledge of pesticide hazards, whereas one fifth (19.5%) had good knowledge. Retailers of agricultural inputs were the first priority of farmers among information sources, followed by neighboring farmers and personal experience. Structural equation modeling (SEM) showed a positive relationship between farmers' knowledge of pesticide hazards (causal impact 0.84) as well as farmers' use of information sources (causal impact 0.52) with their attitudes towards the use of pesticides. Data provide novel information on the role of risk knowledge in farmers' attitudes towards the use of pesticides and extends existing information on the role of farmers' use of information sources in decisions for pesticide use. Improving farmers’ knowledge of pesticide risk and providing valid sources of information are fundamental for minimizing pesticide overuse in cereal production in Moghan Plain, Iran.

Field trials were conducted at two different geographical locations to study the effect of pesticide protection and its consequence on the mycotoxin level, ergosterol and quality parameters of wheat. The treatments involved the application of: herbicide (aryloxyalcanoic and benzoic acid), a set of two (benzimidazole and strobilurin) or three (triazole and morpholine) fungicides and a mix of herbicide and fungicides. Polish and Kazakh varieties of wheat were monitored in a three-year study. Weed populations were controlled by MCPA and dicamba, and a reduction of mycotoxin in wheat grain was observed at both geographical locations. The most significant reduction of the mycotoxin (trichothecenes, fumonisins and zearalenone) levels resulted from the application of combined MCPA/dicamba (BBCH 19–28) and thiophanate methyl/azoxytrobin (BBCH 44–58) and propioconazole/cyproconazole/tebuconazole/triadimenol/spiroxamine (BBCH 68–77). The highest concentrations of zearalenone and deoxynivalenol were detected in the control plots (571.0 and 151.0 μg/kg). The relationships between the fungal biomarker ergosterol and mycotoxins, were observed. The highest levels of ergosterol and contamination with mycotoxin were obtained for the Kazakh and Polish cereals in 2016.

Catchweed Bedstraw (Galium aparine) is a problematic weed, which has become increasingly difficult to control with herbicides in Iran. The aim of this study was to screen selected putative-resistant populations of G. aparine for resistance to auxinic herbicides 2,4-D+MCPA and ALS-inhibiting herbicides sulfosulfuron, tribenuron-methyl, mesosulfuron-methyl + iodosulfuron-methyl-sodium. Populations of G. aparine were collected from different wheat fields in the west of Kermanshah, where herbicide-use pattern is typical for Iran. Herbicide resistance to premixed herbicide 2,4-D+MCPA was confirmed in several populations. More populations of G. aparine showed cross-resistance to ALS-inhibiting herbicides examined in this research. Some populations were found to have developed multiple resistant to both auxinic and ALS herbicides. Generally, the level of resistance to ALS-inhibitor herbicides was higher than that of auxin analog herbicides. RESUMO: Galium aparine é uma espécie de planta daninha problemática, que se tornou cada vez mais difícil de controlar com herbicidas no Irã. O objetivo deste estudo foi selecionar populações resistentes putativas de G. aparine quanto à resistência a herbicidas auxínicos 2,4-D + MCPA e herbicidas inibidores da ALS sulfosulfuron, tribenuron-methyl, mesosulfuron-methyl + iodossulfuron-methyl-sodium. Populações de G. aparine foram coletadas de diferentes campos de trigo no oeste de Kermanshah, onde o padrão de uso de herbicidas é típico para o Irã. Resistência herbicida ao herbicida pré-misturado 2,4-D + MCPA foi confirmada em várias populações. Mais populações de G. aparine mostraram resistência cruzada aos herbicidas inibidores da ALS examinados nesta pesquisa. Descobriu-se que algumas populações desenvolveram múltiplas resistências aos herbicidas auxínicos e ALS. Em geral, o nível de resistência aos herbicidas inibidores da ALS foi maior do que o dos herbicidas análogos à auxina.

We investigated pH taxis inBacillus subtilis. This bacterium was found to perform bidirectional taxis in response to external pH gradients, enabling it to preferentially migrate to neutral environments. We next investigated the chemoreceptors involved in sensing pH gradients. We found that four chemoreceptors are involved in sensing pH: McpA and TlpA for sensing acidic environments and McpB and TlpB for alkaline ones. In addition, TlpA was found to also weakly sense alkaline environments. By analyzing chimeras between McpA and TlpB, the principal acid and base-sensing chemoreceptors, we identified four critical amino-acid residues – Thr199, Gln200, His273, and Glu274on McpA and Lys199, Glu200, Gln273, and Asp274on TlpB – involved in sensing pH. Swapping these four residues between McpA and TlpB converted the former into a base receptor and the latter into an acid receptor. Based on the results, we propose that disruption of hydrogen bonding between the adjacent residues upon pH changes induces signaling. Collectively, our results further our understanding of chemotaxis inB. subtilisand provide a new model for pH sensing in bacteria.IMPORTANCEMany bacteria can sense the pH in their environment and then use this information to direct their movement towards more favorable locations. In this study, we investigated the pH sensing mechanism inBacillus subtilis. This bacterium preferentially migrates to neutral environments. It employs four chemoreceptors to sense pH. Two are involved in sensing acidic environments and two are involved in sensing alkaline ones. To identify the mechanism for pH sensing, we constructed receptor chimeras of acid and base sensing chemoreceptors. By analyzing the response of these chimeric receptors, we were able to identify four critical amino-acid residues involved in pH sensing and propose a model for the pH sensing mechanism inB. subtilis.

Phenoxyacetate herbicides, such as 2,4-D and MCPA, having a high toxicity to non-target organisms are commonly used for controlling broadleaf weeds in agriculture. However, novel and environmentally friendly analogs are constantly sought after. For this purpose, various substituents at the phenyl group have been tested to find the optimal balance between the potent herbicidal activity and safety for non-target species. In this work, we investigated the influence of the oxygen by sulfur replacement in the phenoxy moiety of ammonium chlorophenoxyacetates on the toxicity towards aquatic organisms, such as bacteria (Vibrio fischeri), water flea (Daphnia magna) and freshwater fish (Pimephales promelas) by determining experimental (Microtox® test – V. fischeri) and predicted (ACD Lab Percepta software – D. magna, P. promelas) EC50/LC50 values. The achieved results showed that in contrary to the literature observations, where O-compounds were more toxic than their S-analogs (urea/thiourea), the O/S replacement in chlorophenoxyacetate significantly increased ecotoxicity of the S-analogs (up to 11 times). Moreover, one- and two-substituted phenoxyacetates in the form of ammonium salts were less toxic to V. fischeri than the commercially available phenoxy herbicides in the acid form. The logP/logD values were also calculated to understand hydro/lipophilic nature of the investigated compounds and differences in their toxicity.

The removal of contaminants from the environment can be enhanced by interactions between structurally-related plant secondary metabolites (PSMs), selected xenobiotics and microorganisms. The aim of this study was to investigate the effect of selected PSMs (ferulic acid&mdash, FA, syringic acid&mdash, SA) on the removal of structurally-similar phenoxy herbicides (PHs): 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA). The study also examines the biodegradation potential of soil bacteria, based on the occurrence of functional tdfA-like genes, and the ecotoxicity of the samples against two test species: Sinapis alba L. and Lepidium sativum L. The microbial cultures spiked with the PSMs demonstrated higher phenoxy acid removal: 97&ndash, 100% in the case of 2,4-D and 99%&ndash, 100% for MCPA. These values ranged from 5% to 100% for control samples not amended with FA or SA. The higher herbicide removal associated with PSM spiking can be attributed to acceleration of the microbial degradation processes. Our findings showed that the addition of SA particularly stimulated the occurrence of the total number of tfdA genes, with this presence being higher than that observed in the unamended samples. PSM spiking was also found to have a beneficial effect on ecotoxicity mitigation, reflected in high (102%) stimulation of root growth by the test species.

Changes in weed communities due to changes of climate and agricultural practices have already been indicated. Cattail (Typha spp.) is considered as a noxious invasive species with an increasing dispersal in Greece and other countries, where it starts to become a serious problem particularly in wet areas and especially for perennial crops. Pot and field experiments were conducted in order to evaluate the efficacy of several herbicides and mowing against cattail. The results of the present study revealed the low efficacy of several herbicides (like imazamox, 2,4-D and MCPA) against Typha spp. plants. On the other hand, pot experiments showed that especially glufosinate and glyphosate (in high rate) killed the majority of cattail plants grown by rhizomes. Moreover, they key result of our field experiment is the strong indication of a synergistic action of mowing and chemical control, especially in the case of glufosinate and glyphosate. The case of Typha spp. confirms that the integration of several control methods and agronomic practices may ensure an efficient, long-term management of noxious and invasive weeds.

The aim of the study was to evaluate the effect of herbicidal ionic liquids on the population changes of microorganisms used in a batch anaerobic digester. The influence of the following ionic liquids: benzalkonium (2,4-dichlorophenoxy)acetate (BA)(2,4-D), benzalkonium (4-chloro-2-methylphenoxy)acetate (BA)(MCPA), didecyldimethylammonium (2,4-dichlorophenoxy)acetate (DDA)(2,4-D), didecyldimethylammonium (4-chloro-2-methylphenoxy)acetate (DDA)(MCPA), as well as reference herbicides (4-chloro-2-methylphenoxy)acetic acid (MCPA) and (2,4-dichlorophenoxy)acetic acid (2,4-D) in the form of sodium salts on biogas production efficiency was investigated. The effective concentration (EC50) values were determined for all tested compounds. (MCPA)&minus, was the most toxic, with an EC50 value of 38.6&ndash, 41.2 mg/L. The EC50 for 2,4-D was 55.7&ndash, 59.8 mg/L. The addition of the test substances resulted in changes of the population structure of the microbiota which formed the fermentation pulp. The research was based on 16S rDNA analysis with the use of the Next Generation Sequencing method and the MiSeq platform (Illumina, San Diego, CA, USA). There was a significant decrease in bacteria belonging to Firmicutes and Archaea belonging to Euryarchaeota. A significant decrease of the biodiversity of the methane fermentation microbiota was also established, which was expressed by the decrease of the operational taxonomic units (OTUs) and the value of Shannon&rsquo, s entropy. In order to determine the functional potential of bacterial metapopulations based on the 16SrDNAprofile, the PICRUSt(Phylogenetic Investigation of Communities by Reconstruction of Unobserved States)tool was used, which allowed to determine the gene potency of microorganisms and their ability to biodegrade the herbicides. In the framework of the conducted analysis, no key genes related to the biodegradation of MCPA or 2,4-D were found, and the observed decrease of their content in the supernatant liquid was caused by their sorption on bacterial biomass.

Harrowing is one of the most popular mechanical methods to control weeds. Nevertheless, the relationship between the effect of different harrowing intensities using spike-tooth harrow in barley-pea intercrop on the yield and mycoflora of grains has not yet been studied. Therefore, the aim of this study was to assess the effect of harrow intensity using spike-tooth harrow in barley-pea mixture on the mycological quality of harvested grains, grain yield, as well as influence of barley and pea grain moisture on the abundance of fungi. The field experiment was carried out during 2010&ndash, 2012, and it was conducted using a randomized complete block design with four replicates. Weed control was mechanical and chemical. In this study, we have shown that harrowing in barley-pea intercrops does not reduce the yield of either mixture components, both with respect to grain quantity or mycological quality after harvest, compared to controls&mdash, without harrowing and the herbicide MCPA (2-methyl-4-chlorophenoxyacetic acid). However, increasing the intensity of harrowing did not result in a consistently larger crop yield or reduction in fungal abundance in the grains. The grains&rsquo, internal structures and surface of both tested components of the mixture were colonized to a large extent by cosmopolitan fungi, of which Alternaria alternata (Fr.) Keissl. was the most abundant.

Soliva sessilis is a troublesome annual weed species in New Zealand turfgrass. This weed has been controlled selectively in New Zealand turfgrass for many years using pyridine herbicides such as clopyralid. However, in some golf courses, the continuous application of pyridine herbicides has resulted in the selection of S. sessilis populations that are resistant to these herbicides. This study focuses on a clopyralid-resistant population of S. sessilis collected from a golf course with a long history of clopyralid applications. The resistant phenotype of S. sessilis was highly resistant to clopyralid (over 225-fold). It was also cross-resistant to dicamba, MCPA and picloram but not mecoprop. The level of resistance to dicamba was high (7-14-fold) but much lower (2-3-fold) for both MCPA and picloram. The phenotype was morphologically distinct from its susceptible counterpart. Individuals of the clopyralid-resistant phenotype had fewer lobes on their leaves and were slightly larger compared to the susceptible phenotype. Resistant individuals also had a larger leaf area and greater root dry weight than the susceptible plants. An evaluation of internal transcribed spacer (ITS) regions confirmed that clopyralid-resistant phenotypes are conspecific with S. sessilis. In summary, the cross-resistance to several auxinic herbicides in this S. sessilis phenotype greatly reduces chemical options for controlling it; thus, other integrated management practices may be needed such as using turfgrass competition to reduce weed germination. However, the morphological differences between resistant and susceptible plants make it easy to see, which will help with its management.

Herbicides constitute one of the major problems in the environment mainly because of their ability to entering into plant and microorganisms metabolic pathways. The aim of the study was to give an insight into behaviour of selected herbicides: MCPA and sulfosulfuron in soil/plants after Bacillus cereus and Pseudomonas fluorescens application. The single first-order degradation model (SFO) was used to simulate the decrease of residual mass of herbicides in the soil/wheat system with/without bacteria using LC-MS/MS. The greatest loss of MCPA concentration was noticed in soil enriched with B. cereus (99.7%) on 31st day from application, while the highest decrease of sulfosulfuron was determined in soil enriched with P. fluorescens (97%) on 46th day from application. In wheat, the greatest pesticides loss (98%–99.8%) was noticed on 31st day from application, without bacteria addition. The study presents the influence of pesticides on enzyme in soil, where the higher average dehydrogenase activity was observed for combination with B. cereus approx. 150% as compared to the control. Moreover, pesticides impact on catalase, superoxide dismutase and NADH peroxidase activity, level of lipid peroxidation, thiol content in plants was determined. Increased reactive oxygen species production caused an oxidation of thiol groups and lipid peroxidation. The obtained results indicated that the use of B. cereus and P. fluorescens may reduce harmful effects of stress caused by herbicides. The presented study is the first step in the analysis of chemical and biological properties changes in the soil/wheat system after the application of herbicides and microorganisms.

Weed control using a single herbicide with same active ingredients can add the risk of weed resistance. Using mixed herbicides can increase the spectrum of weeds controlled, and inhibit weed resistance. Herbicide mixture with two or more types of active ingredients will show the interactions between one and another ingredient. These interactions could be synergistic, antagonistic, and additive. The research was to determine the response of mixed herbicide Bentazon, MCPA 460 g. L⁻¹ and their mixed characteristic. This experiment was conducted from June until August 2019 in the greenhouse at the Faculty of Agriculture, Universitas Padjadjaran. The treatment consisted of three types of herbicides with six dose levels, namely a single herbicide of Bentazon 400 g. L⁻¹ and MCPA 60 g. L⁻¹ (4; 2; 1; 0.5; 0.25; 0 L.ha⁻¹), a mixed herbicide Bentazon MCPA 460 g.L⁻¹ (5; 2.5; 1.25; 0.625; 0.3215; 0 L.ha⁻¹) with four replications. The target weeds tested were Spenochlea zeylanica, Ludwigia hyssopifolia, Fimbristylis miliacea, and Cyperus iria was taken from the Ciparay area. Data were analysed by linear regression analysis and multiplicative survival model (MSM) method to determine the LD50 treatment and expectation. The result showed that compound herbicides of Bentazon and MCPA LD50 treatment (0,3857 g.ha⁻¹) had smaller value than LD50 expectation (0,6943 g.ha⁻¹) with a ecotoxicity value of 1.8 (> 1), so that the herbicide mixture was synergistic.

In this study, a bacterial strain of Achromobacter sp. LZ35, which was capable of utilizing 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxy acetic acid (MCPA) as the sole sources of carbon and energy for growth, was isolated from the soil in a disused pesticide factory in Suzhou, China. The optimal 2,4-D degradation by strain LZ35 occurred at 30 °C and pH 8.0 when the initial 2,4-D concentration was 200 mg L−1. Strain LZ35 harbored the conserved 2,4-D/alpha-ketoglutarate dioxygenase (96%) and 2,4-dichlorophenol hydroxylase (99%), and catabolized 2,4-D via the intermediate 2,4-dichlorophenol. The inoculation of 7.8 × 106 CFU g−1 soil of strain LZ35 cells to 2,4-D-contaminated soil could efficiently remove over 75 and 90% of 100 and 50 mg L−1 2,4-D in 12 days and significantly released the phytotoxicity of maize caused by the 2,4-D residue. This is the first report of an Achromobacter sp. strain that was capable of mineralizing both 2,4-D and MCPA. This study provides us a promising candidate for its application in the bioremediation of 2,4-D- or MCPA-contaminated sites.

To evaluate the allelopathic effects of major crops and weeds, studies were conducted during 2011–12 and 2012–13 by utilizing water extracts of allelopathic plants namely rice (Oryza sativa L.), Parthenium hysterophorus L., Phragmites australis Cav., and Datura alba L. with reduced rates of fenoxaprop-p-ethyl and bromoxynil plus MCPA to control weeds. Application of Phragmites australis and Parthenium hysterophorus along with lower rates of fenoxaprop-p-ethyl and bromoxynil plus MCPA showed promising results by controlling weeds and improving yield. Parthenium hysterophorus extract with half of the recommended dose of fenoxaprop-p-ethyl and bromoxynil plus MCPA reduced weed density by 51 and 50% during year 1 and year 2, respectively, compared with the control. Phragmites australis extract with half of the recommended dose of fenoxaprop-p-ethyl produced grain yield (5.7 and 6.1 t ha−1 during year 1 and 2, respectively) in wheat. However, these results were also at par with Parthenium hysterophorus and Datura alba extracts in combinations with half the recommended doses of the above mentioned herbicides. The study of microbial activity showed higher amount of mineralizable carbon in D. alba with half the recommended dose of fenoxaprop-p-ethyl treated plots (0.073 g during both the years). The lowest amount of mineralizable carbon (0.035 and 0.030 g during year 1 and 2, respectively) was observed in the control plots. The presence of allelopathic plants in field crops and subsequent mixing in soil by tillage may create problems in crop production. Therefore, further studies are suggested to fully explore all the possible interactions among allelochemicals and herbicides.