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The management of invasive weeds on both arable and non-arable land is a vast challenge. Converting these invasive weeds into biochar and using them to control the fate of herbicides in soil could be an effective strategy within the concept of turning waste into a wealth product. In this study, the fate of imazethapyr (IMZ), a commonly used herbicide in various crops, was investigated by introducing such weeds as biochar, i.e., Parthenium hysterophorus (PB) and Lantana camara (LB) in sandy loam soil. In terms of kinetics, the pseudo-second order (PSO) model provided the best fit for both biochar-mixed soils. More IMZ was sorbed onto LB-mixed soil compared to PB-mixed soil. When compared to the control (no biochar), both PB and LB biochars (at concentrations of 0.2% and 0.5%) increased IMZ adsorption, although the extent of this effect varied depending on the dosage and type of biochar. The Freundlich adsorption isotherm provided a satisfactory explanation for IMZ adsorption in soil/soil mixed with biochar, with the adsorption process exhibiting high nonlinearity. The values of Gibb's free energy change (ΔG) were negative for both adsorption and desorption in soil/soil mixed with biochar, indicating that sorption was exothermic and spontaneous. Both types of biochar significantly affect IMZ dissipation, with higher degradation observed in LB-amended soil compared to PB-amended soil. Hence, the findings suggest that the preparation of biochar from invasive weeds and its utilization for managing the fate of herbicides can effectively reduce the residual toxicity of IMZ in treated agroecosystems in tropical and subtropical regions., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Imazethapyr is a widely used imidazolinone herbicide worldwide, and its potential adverse effects on non-target plants have raised concerns. Understanding the mechanisms of imazethapyr phytotoxicity is crucial for its agro-ecological risk assessment. Here, the comprehensive molecular responses and metabolic alterations of Arabidopsis in response to imazethapyr were investigated. Our results showed that root exposure to imazethapyr inhibited shoot growth, reduced chlorophyll contents, induced photoinhibition and decreased photosynthetic activity. By non-target metabolomic analysis, we identified 75 metabolites that were significantly changed after imazethapyr exposure, and they are mainly enriched in carbohydrate, lipid and amino acid metabolism. Transcriptomic analysis confirmed that imazethapyr significantly downregulated the genes involved in photosynthetic electron transport and the carbon cycle. In detail, 48 genes in the photosynthetic lightreaction and 11 genes in Calvin cycle were downregulated. Additionally, the downregulation of genes related to electron transport in mitochondria provides strong evidence for imazethapyr inhibiting photosynthetic carbon fixation and cellular energy metabolism as one of mechanisms of toxicity. These results revealed the molecular and metabolic basis of imazethapyr toxicity on non-target plants, contributing to environmental risk assessment and mitigate negative impact of imazethapyr residues in agricultural soils., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Excessive or inappropriate applications of imazethapyr cause severe ecological deteriorations and health risks in human. A novel bacterial strain, i.e., Bacillus marcorestinctum YN1, was isolated to efficiently degrade imazethapyr, with the degradation pathways and intermediates predicted. Protein mass spectrometry analysis identified enzymes in strain YN1 potentially involved in imazethapyr biodegradation, including methylenetetrahydrofolate dehydrogenase, carbon-nitrogen family hydrolase, heme degrading monooxygenase, and cytochrome P450. The strain YN1 was further immobilized with biochar (BC600) prepared from mushroom waste (i.e., spent mushroom substrate) by pyrolysis at 600 °C to evaluate its degrading characteristics of imazethapyr. Scanning electron microscope observation showed that strain YN1 was adsorbed in the rich pore structure of BC600 and the adsorption efficiency reached the maximum level of 88.02% in 6 h. Both energy dispersive X-ray and Fourier transform infrared spectroscopy analyses showed that BC600 contained many elements and functional groups. The results of liquid chromatography showed that biochar-immobilized strain YN1 (IBC-YN1) improved the degradation rate of imazethapyr from 79.2% to 87.4%. The degradation rate of imazethapyr by IBC-YN1 could still reach 81.0% in the third recycle, while the bacterial survival rate was 67.73% after 180 d storage at 4 °C. The treatment of IBC-YN1 significantly shortened the half-life of imazethapyr in non-sterilized soil from 35.51 to 11.36 d, and the vegetative growth of imazethapyr sensitive crop plant (i.e., Cucumis sativus L.) was significantly increased in soil remediated, showing that the inhibition rate of root length and fresh weight were decreased by 12.45% and 38.49% respectively. This study exhanced our understanding of microbial catabolism of imazethapyr, and provided a potential in situ remediation strategy for improving the soil environment polluted by imazethapyr., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The imidazolinone group of herbicides generally work for controlling weeds by limiting the synthesis of the aceto-hydroxy-acid enzyme, which is linked to the biosynthesis of branched-chain amino acids in plant cells. The herbicide imazethapyr is from the class and the active ingredient of this herbicide is the same as other herbicides Contour, Hammer, Overtop, Passport, Pivot, Pursuit, Pursuit Plus, and Resolve. It is commonly used for controlling weeds in soybeans, alfalfa hay, corn, rice, peanuts, etc . Generally, the herbicide imazethapyr is safe and non-toxic for target crops and environmentally friendly when it is used at low concentration levels. Even though crops are extremely susceptible to herbicide treatment at the seedling stage, there have been no observations of its higher dose on lentils ( Lens culinaris Medik.) at that stage. The current study reports the consequence of imazethapyr treatment on phenolic acid and flavonoid contents along with the antioxidant activity of the phenolic extract. Imazethapyr treatment significantly increased the activities of several antioxidant enzymes, including phenylalanine ammonia lyase (PAL), phenol oxidase (POD), glutathione reductase (GR), and glutathione-s-transferase (GST), in lentil seedlings at doses of 0 RFD, 0.5 RFD, 1 RFD, 1.25 RFD, 1.5 RFD, and 2 RFD. Application of imazethapyr resulted in the 3.2 to 26.31 and 4.57-27.85% increase in mean phenolic acid and flavonoid content, respectively, over control. However, the consequent fold increase in mean antioxidant activity under 2, 2- diphenylpicrylhdrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assay system was in the range of 1.17-1.85 and 1.47-2.03%. Mean PAL and POD activities increased by 1.63 to 3.66 and 1.71 to 3.35-fold, respectively, in agreement with the rise in phenolic compounds, indicating that these enzyme's activities were modulated in response to herbicide treatment. Following herbicide treatments, the mean thiol content also increased significantly in corroboration with the enhancement in GR activity in a dose-dependent approach. A similar increase in GST activity was also observed with increasing herbicide dose., Competing Interests: The authors declare that they have no competing interests., (© 2024 Kumar et al.)

Weed invasion causes significant yield losses in lentil. Imazethapyr (IM), a broad-spectrum herbicide inhibits the biosynthesis of branched chain amino acids necessary for plant growth. Plant growth depends upon translocation of photo-assimilates and their partitioning regulated by carbon and nitrogen metabolism. This study aimed to investigate the impact of imazethapyr spray on carbon and nitrogen metabolism in tolerant (LL1397 and LL1612) and susceptible (FLIP2004-7L and PL07) lentil genotypes during vegetative and reproductive development. Significantly higher activities of invertases and sucrose synthase (cleavage) in leaves and in podwall and seeds during early phase of development in tolerant genotypes were observed as compared to susceptible genotypes under herbicide stress that might be responsible for providing hexoses required for their growth. Activities of sucrose synthesizing enzymes, sucrose phosphate synthase and sucrose synthase (synthesis) increased significantly in podwalls and seeds of LL1397 and LL1612 genotypes during later phase of development towards maturity while the activities decreased in FLIP2004-7L and PL07 genotypes under herbicide stress. Activities of nitrate and nitrite reductase, glutamine 2-oxoglutarate aminotransferase, glutamine synthetase and glutamate dehydrogenase were increased in leaves, podwalls and seeds of LL1397 and LL1612 under herbicide stress. A proper synchronization of carbon and nitrogen metabolism in tolerant lentil genotypes during vegetative and reproductive phase might be one of the mechanisms for their recovery from herbicide stress. This first ever comprehensive information will provide a basis for future studies on the molecular mechanism of source sink relationship in lentil under herbicide stress and will be utilized in breeding programmes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Herbicide-resistant weeds pose a serious threat to world food production. The rapid and widespread development of target-site based resistance limits the application of herbicides. Alopecurus myosuroides Huds. (blackgrass) has spread rapidly in winter wheat regions in China, and the field recommended dose of ALS herbicides no longer controls blackgrass populations in recent years. A highly resistant population TW18(R) was collected in 2018 from Shandong Province. Dose-response assays showed that the TW18 was resistant to mesosulfuron-methyl, flucarbazone-sodium, and imazethapyr, with resistance index values of 5.96, 6.1, and 4.09, respectively. DNA sequencing of the TW18 population revealed a Phe206Tyr (F206Y) mutation in the ALS, which was not yet reported. Blackgrass ALS gene with the F206Y mutation (R gene) was expressed in Arabidopsis and rice. Transgenic studies have shown that both Arabidopsis and rice expressing this R gene have resistance to imazethapyr. However, it did not confer resistance to tribenuron methyl and florasulam in transgenic Arabidopsis. This study showed that the F206Y substitution caused herbicide resistance in blackgrass. To our knowledge, this is the first-reported F206Y mutation of a weed species in the natural environment. Transgenic plants showed this functional site could be utilized to generate imazethapyr-resistant rice to control herbicide-resistant weed damage., (Copyright © 2022. Published by Elsevier Inc.)

Common lambsquarters (Chenopodium album L.) is a broadleaf weed that can severely damage soybean fields. Two C. album populations (1744 and 1731) suspected resistant to imazethapyr were investigated for resistance levels to imazethapyr, thifensulfuron-methyl, and fomesafen and their resistance mechanisms were investigated. Whole-plant dose-response assays revealed that, compared to the susceptible (S) population, the 1744 population was 16.5-fold resistant to imazethapyr, slightly resistant to thifensulfuron-methyl (resistance index [R/S], <3). The 1731 population was 18.8-fold resistant to imazethapyr, 2.9-fold resistant to thifensulfuron-methyl, and 5.1-fold resistant to fomesafen. In vitro acetolactate synthase (ALS) assays showed 17.1-fold and 19.3-fold resistance levels of 1744 and 1731 populations to imazethapyr respectively. ALS gene sequence analysis identified Ala122Thr amino acid substitution in the 1744 population and Ser653Thr amino acid substitution in the 1731 population. No mutations of the protoporphyrinogen oxidase (PPO) gene were detected. However, pre-treatment with malathion reversed fomesafen resistance, suggesting nontarget-site resistance mechanisms likely play a role in the 1731 population., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Descurainia sophia L. is one of the most notorious weeds infesting winter wheat in China. Mutations at Pro197 in acetolactate synthase (ALS) results in resistance of D. sophia to tribenuron-methyl and cross-resistance to many ALS inhibitors. Negative cross-resistance to imazethapyr was observed in tribenuron-methyl-resistant (TR) D. sophia with the Pro197Ser mutation in a previous study. In the present research, another TR D. sophia with the Pro197Ser mutation was obtained. To explore the mechanisms of negative cross-resistance, the ALS sensitivity, the absorption and metabolism of imazethapyr in tribenuron-methyl-susceptible (TS) and TR D. sophia were studied., Results: The TR D. sophia population with the Pro197Ser mutation (pHB23) displayed negative cross-resistance to imazethapyr and no cross-resistance to imazamox and imazapic. In contrast, TR D. sophia populations with other Pro197 mutations had no or low resistance to imazethapyr. The ALS in the pHB23 population was more susceptible to imazethapyr than that in the TS population. There was no difference in the absorption of imazethapyr, imazamox, and imazapic between TS and pHB23 plants. However, the metabolism of imazethapyr in TS D. sophia was faster than that in pHB23 plants up to 1 week after treatment. There was no significant difference in the metabolism of imazamox and imazapic between TS and pHB23 plants., Conclusion: The TR D. sophia population with the Pro197Ser mutation exhibited negative cross-resistance to imazethapyr, which was likely due to reduced metabolism and increased sensitivity of ALS to imazethapyr. © 2021 Society of Chemical Industry., (© 2021 Society of Chemical Industry.)

Herbicide resistance is broadly recognized as the adaptive evolution of weed populations to the intense selection pressure imposed by the herbicide applications. Here, we tested whether transcriptional gene silencing (TGS) and RNA-directed DNA Methylation (RdDM) pathways modulate resistance to commonly applied herbicides. Using Arabidopsis thaliana wild-type plants exposed to sublethal doses of glyphosate, imazethapyr, and 2,4-D, we found a partial loss of TGS and increased susceptibility to herbicides in six out of 11 tested TGS/RdDM mutants. Mutation in REPRESSOR OF SILENCING 1 ( ROS1 ), that plays an important role in DNA demethylation, leading to strongly increased susceptibility to all applied herbicides, and imazethapyr in particular. Transcriptomic analysis of the imazethapyr-treated wild type and ros1 plants revealed a relation of the herbicide upregulated genes to chemical stimulus, secondary metabolism, stress condition, flavonoid biosynthesis, and epigenetic processes. Hypersensitivity to imazethapyr of the flavonoid biosynthesis component TRANSPARENT TESTA 4 ( TT4 ) mutant plants strongly suggests that ROS1-dependent accumulation of flavonoids is an important mechanism for herbicide stress response in A. thaliana . In summary, our study shows that herbicide treatment affects transcriptional gene silencing pathways and that misregulation of these pathways makes Arabidopsis plants more sensitive to herbicide treatment.

Imazethapyr (IMZT) is a typical chiral pesticide with two enantiomers with the R-IMZT having the main herbicidal activity. However, the enantioselectivity of the effects of IMZT enantiomers on human and animals is still unclear. In this study, a nuclear magnetic resonance (NMR)-based metabolomics method and determination of oxidative stress were used to evaluate the enantioselectivity of IMZT enantiomers in mice. The results showed that the R-IMZT caused larger disturbances of endogenous metabolites and the S-IMZT had stronger interferences to oxidation defense system. The significantly perturbed metabolic pathways in mice exposed to the R-enantiomer were the valine, leucine and isoleucine biosynthesis pathway as well as the phenylalanine, tyrosine and tryptophan biosynthesis pathway. However, exposure of mice to the S-enantiomer did not significantly affect the metabolic pathways, but exposure led to an increase of catalase (CAT) activity and an increase in malondialdehyde (MDA) content in the liver. These results indicate that we need to conduct a more comprehensive assessment of the health risks of pesticide monomers in the future. In a word, these results provide more evidence for assessing the differences in health risks of IMZT enantiomers to mammals as well as provide more references for the promotion and use of pesticide monomers in the future., Competing Interests: Declaration of Competing Interest The authors disclose no conflict of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The phytostimulation is a phytoremediation technique that can be used to remediate area contaminated with herbicides. It is necessary to select plants with high capacity to stimulate soil microbial activity. The present work aimed at evaluating seven plant species regarding their ability to phytostimulate soil and enhance the degradation of the herbicides imazethapyr, imazapic and imazapyr in a lowland soil. An Alfisol Albaqualf was cultivated with the following species, Canavalia ensiformis , Glycine max , Oryza sativa cultivar PUITÁ INTA CL, Lolium multiflorum , Vicia sativa and consortium Lotus corniculatus + Trifolium repens . The rhizosphere of these plants and non-rhizospheric (uncultivated soil) as a control were contaminated in laboratory with analytical standart of the three herbicides, at rates of 0, 150, 300 and 750 g a.i. ha -1 , in separate assays. Biodegradation was estimated by quantifying C-CO 2 production and through analysis of herbicides residues in soil using liquid chromatography. Results show that biodegradation of herbicides imazethapyr, imazapic and imazapyr was higher in vegetated soil than in unvegetated soil. The leguminous species Canavalia ensiformis , Glycine max , Vicia sativa and consortium of Lotus corniculatus + Trifolium repens showed a great capacity to promote soil microbial, resulting in average biodegradation rates of 91, 92 and 93% for herbicides imazethapyr, imazapic and imazapyr in soil, respectively.

The enantioselective effects of imazethapyr (IM) enantiomers on wheat seedlings in a hydroponic medium were studied. R-IM at 0.05mg/L exerted a stronger inhibitory effect on shoot weight and root weight than 0.05mg/L S-IM, suggesting that R-IM more severely inhibited growth. Oxidative damage, based on the anthocyanin content, malondialdehyde (MDA) content, antioxidant enzyme activities and transcript levels of antioxidant enzyme genes, were studied together with the cellular ultrastructure of wheat leaves. The anthocyanin and MDA contents in the R-IM treatment group were significantly increased compared with those in the control group, but no significant changes were observed in the S-IM treatment group. The antioxidant enzyme activities of CAT and SOD were inhibited by 0.32- and 0.73-fold, respectively, in the 14day R-IM treatment group compared to those in the control. However, the transcript levels of antioxidant enzyme genes, including CuZnSOD, POD and CAT, were downregulated in the 14day R-IM exposure group, but those of DHAR were not. The number and size of starch granules increased and chloroplast swelling was observed in wheat leaf cells after R-IM exposure, which showed that photosynthetic functions were potentially disturbed. These results directly or indirectly imply that R-IM exposure causes more oxidative stress and exerts a stronger negative effect on wheat than S-IM. A metabolomics approach revealed that the tricarboxylic acid cycle was heavily suppressed by R-IM treatment. Some amino acids (proline, threonine, lysine, valine) were increased by only the R-IM treatment, indicating the activation of antioxidant pathways. The decrease in a series of fatty acids implied that the cell membrane composition changed in response to R-IM. These results provide a deeper understanding of the enantioselective effects of IM enantiomers on the molecular and metabolic responses in wheat seedlings., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The chiral herbicide imazethapyr (IM) is frequently used to control weeds in soybean fields in northeast China. However, the impact of IM enantiomers on microbial communities in soil is still unknown. Genetic markers (16S rRNA V3-V4 regions) were used to characterize and evaluate the variation of the bacterial communities potentially effected by IM enantiomers. Globally, the bacterial community structure based on the OTU profiles in (-)-R-IM-treated soils was significantly different from those in (+)-S-IM-treated soils, and the differences were enlarged with the treatment dose increasing. Interestingly, the Rhizobiaceae family and several other beneficial bacteria, including Bradyrhizobium, Methylobacterium, and Paenibacillus, were strongly enriched in (-)-R-IM treatment compared to (+)-S-IM treatment. In contrast, the pathogenic bacteria, including Erwinia, Pseudomonas, Burkholderia, Streptomyces, and Agrobacterium, were suppressed in the presence of (-)-R-IM compared to (+)-S-IM. Furthermore, we also observed that the bacterial community structure in (-)-R-IM-treated soils was more quickly restored to its original state compared with those in (+)-S-IM-treated soils. These findings unveil a new role of chiral herbicide in the development of soil microbial ecology and provide theoretical support for the application of low-persistence, high-efficiency, and eco-friendly optical rotatory (-)-R-IM.

A direct, controlled comparison of the photodegradation of imazethapyr has been made between imazethapyr in aqueous solutions, imazethapyr on the surface of epicuticular waxes of corn and soybean plants, and imazethapyr on the surface of intact corn and soybean plant leaves. In some experiments, the imazethapyr solutions were allowed to evaporate partially or fully after application to better model environmental conditions. The photodegradation of imazethapyr was fastest in aqueous solutions (k = 0.16 ± 0.02 h -1 ) and slowest on the surface of corn and soybean plants (k corn  = 0.00048 ± 0.001 h -1 and k soy  = 0.00054 ± 0.003 h -1 ). Experiments allowing evaporation during irradiation have intermediate rate constants (e.g., k corn  = 0.082 ± 0.005 h -1 ). Finally, identification of photoproducts was also examined on epicuticular waxes of corn and soybean plants for the first time.

Imidazolinone group herbicides are known for longer persistence in soil. Therefore, a laboratory study was performed to evaluate the persistence of pre-mix formulation of two imidazolinone herbicides-imazethapyr and imazamox in clay and sandy loam soils. Herbicide formulation was applied at 70 and 140 g a.i. ha -1 equivalent to recommended doses in legumes. For achieving efficient sample preparation, three methods namely ultrasonic-assisted extraction (UAE), matrix solid phase dispersion (MSPD), and solid phase extraction (SPE) were optimized. MSPD gave better recoveries (85.22 to 96.00%) over SPE (80.10 to 84.78%) and UAE (56.44 to 66.20%). Residues were estimated using gas chromatography tandem mass spectrometry (GC-MS/MS) which is previously not reported in open literature. Dissipation followed first-order kinetics and half-life period of 23.5 to 43.3 days in clay loam and 19.6 to 39.8 days in sandy loam soil. The results revealed the persistent nature of pre-mix formulation of both herbicides as only 64.2 to 86.6% residues dissipated after 90 days of application in both soils.

In the present study, the damage recovery capabilities of Boana pulchella tadpoles after acute exposure (96h) to 0.39mg/L concentration of the imazethapyr (IMZT)-based herbicide formulation Pivot ® H (25% IMZT LC 50 value) were assessed during a period of 7 to -21 days. To appraise the recovery capabilities, frequency of micronuclei (MNs), other nuclear abnormalities and DNA single-strand breaks evaluated by single cell gel electrophoresis assay on circulating blood cells were employed as endpoints for genotoxicity. Growth, development, body mass, and morphological abnormalities were also employed as individual endpoints in the recovery assay. Results demonstrated that IMZT induced sublethal effects at both the individual (i.e., loss of keratodonts) and cytogenetic levels (e.g., increase of MN frequency, other nuclear abnormalities and DNA single-strand breaks). At 11 days of the exposure phase, tadpoles recovered their basal levels of frequency of MNs, other nuclear abnormalities, and comets. However, loss of keratodonts, observed at the end of the exposure period, was present up to 21 days thereafter. Finally, axial abnormalities and delay in development stage were observed only during the postexposure phase in IMZT-exposed tadpoles at 18 and 25 days, respectively and were observed until the end of the experiment. This is the first evidence of use the comet assay as cytogenetic biomarker of genotoxicity in evaluating the recovery capabilities of amphibians in general and also those of B. pulchella after exposure to IMZT., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Controlled release formulations of imazethapyr herbicide have been developed employing guar gum-g-cl-polyacrylate/bentonite clay hydrogel composite (GG-HG) and guar gum-g-cl-PNIPAm nano hydrogel (GG-NHG) as carriers, to assess the suitability of biopolymeric hydrogels as controlled herbicide release devices. The kinetics of imazethapyr release from the developed formulations was studied in water and it revealed that the developed formulations of imazethapyr behaved as slow release formulations as compared to commercial formulation. The calculated diffusion exponent (n) values showed that Fickian diffusion was the predominant mechanism of imazethapyr release from the developed formulations. Time for release of half of the loaded imazethapyr (t 1/2 ) ranged between 0.06 and 4.8 days in case of GG-NHG and 4.4 and 12.6 days for the GG-HG formulations. Weed control index (WCI) of GG-HG and GG-NHG formulations was similar to that of the commercial formulation and the herbicidal effect was observed for relatively longer period. Guar gum-based biopolymeric hydrogels in both macro and nano particle size range can serve as potential carriers in developing slow release herbicide formulations.

Photosynthesis is a very important metabolic pathway for plant growth and crop yield. This report investigated the effect of the herbicide imazethapyr on photosynthesis in the Arabidopsis thaliana pnsB3 mutant (a defect in the NDH pathway) and pgr5 mutant (a defect in the PGR5 pathway) to determine which cyclic electron transport chain (CET) of the NDH and PGR5 pathways is more important for protecting the photosynthetic system under herbicide stress. The results showed that 20 μg/L imazethapyr markedly inhibited the growth of the three ecotypes of A. thaliana and produced more anthocyanins and reactive oxygen species (ROS), particularly in the pgr5 mutant. The chlorophyll fluorescence results showed that PSII was severely damaged in the pgr5 mutant. Additionally, the CET was significantly stimulated to protect the photosynthetic system from light damage in Wt and the pnsB3 mutant but not the pgr5 mutant. The real-time PCR analysis indicated that imazethapyr treatment considerably decreased the transcript levels of most photosynthesis-related genes in the three treated groups. Several genes in the PGR5 pathway were significantly induced in the pnsB3 mutant, but no genes in the NDH pathway were induced in the pgr5 mutant. The gene transcription analysis showed that the pgr5 mutant cannot compensate for the deficit in the PGR5 pathway by stimulating the NDH pathway, whereas the pnsB3 mutant can compensate for the deficit in the CET cycle by regulating the PGR5 pathway. The iTRAQ analyses also showed that the photosynthesis system, glycolysis, and TCA cycle suffered the most severe damage in the pgr5 mutant. All of these results showed that the PGR5 pathway is more critical for electron transfer around PSI than the NDH pathway to resist herbicide stress.

We evaluated the effects of the soil organic matter (SOM) composition, distribution between soil aggregates size, and their interactions with the mineral phase on herbicide sorption (alachlor, bentazon, and imazethapyr) in tropical and subtropical Oxisols under no-till systems (NT). Using soil physical fractionation approach, sorption experiments were performed on whole soils and their aggregates. SOM chemistry was assessed by CP/MAS (13)C NMR. The lower sorption observed in tropical soils was attributed to the greater blockage of SOM sorption sites than in subtropical soils. When these sites were exposed upon physical fractionation, sorption of the three herbicides in tropical soils increased, especially for imazethapyr. High amounts of poorly crystallized sesquioxides in these soils may have contributed to masking of sorption sites, indicating that organomineral interactions may lead to blockage of sorption sites on SOM in tropical soils.

Background: Soon after the commercial release of sunflower cultivars resistant to imidazolinone herbicides, several uncontrolled feral radish (Raphanus sativus L.) populations were found in south-eastern Buenos Aires, Argentina. These populations were studied in field, glasshouse and laboratory experiments aiming to characterise their resistance profile and to develop management tools., Results: Three feral radish accessions were highly resistant to ten active ingredients of five families of acetohydroxyacid synthase (AHAS)-inhibiting herbicides. Sequence analysis of the AHAS gene detected a Trp574Leu mutation in all resistant accessions. One accession with an intermediate level of resistance was heterozygous for this mutation, probably owing to gene exchange with a susceptible subpopulation located in the field margin. Herbicide-resistant and herbicide-susceptible radish could be controlled in sunflower by alternative herbicides., Conclusion: This is the first report of feral radish with resistance to herbicides belonging to all the AHAS-inhibiting herbicide families, conferred by Trp574Leu mutation in the AHAS gene. An appropriate herbicide rotation with alternative herbicides such as fluorochloridone or aclonifen and an increase in the diversity of cropping systems are important for minimising the prevalence of these biotypes., (© 2015 Society of Chemical Industry.)

The imazethapyr herbicide (formulation Verosil(®)) was evaluated for phytotoxicity and genotoxicity using a battery of bioassays: (1) the growth inhibition of the green alga Pseudokirchneriella subcapitata, (2) the root growth and germination of the higher plant Lactuca sativa, (3) the genetic damage using the Salmonella/microsome test, and (4) the aneugenic and clastogenic effects on Allium cepa. The Verosil(®) formulation was highly toxic to the non-target green alga (median effective concentration (EC50) = 1.05 ± 0.05 mg active ingredient (a.i.) L(-1)), and concentrations above 10 mg a.i. L(-1) inhibited root elongation in lettuce: relative growth index (RGI) between 0.28 ± 0.01 and 0.66 ± 0.10. No genotoxic effect was observed in S almonella typhimurium at 100 mg a.i. L(-1), either with or without the microsomal fraction. However, significant differences in the frequency of chromosomal aberrations in anaphases and telophases (bridges, chromosome fragments, and vagrants) were observed in A. cepa at concentrations between 0.01 and 1 mg a.i. L(-1) with respect to the control. The frequencies of micronuclei showed significant differences with respect to the control at concentrations between 0.001 and 0.1 mg a.i. L(-1). A very high mitotic index (MI = 93.8 ± 5.8) was observed associated with a high number of cells in the prophase stage at 100 mg a.i. L(-1), indicating cytotoxicity. These results showed that imazethapyr is toxic to the non-target populations in both aquatic and terrestrial ecosystems. This herbicide might also exert clastogenic and aneugenic mitotic damage in higher plants. Therefore, the imazethapyr formulation may constitute an environmental risk to plants.

A two-dimensional HPLC method for the simultaneous direct chiral enantiomeric determination of acid and ester IMI herbicides has been described. Difficulties arising from differences in polarity were overcome. Firstly, the imazaphyr, imazethapyr and imazamethabenz methyl herbicides were separated in a C18 achiral column. Then, their respective enantiomers were separated using a protein chiral AGP(TM) column; a heart-cut mode was used. Mobile phases of the two systems were compatibilized, after optimizing by factorial design using multiple response analysis. The proposed method has been validated by recovery studies from an enriched soil sample. Important enantiomer parameters such as enantioresolution higher than 1.12, enantiomeric ratio (ER) close to 1 and enantiomeric fraction (EF) around 0.5 were obtained for standards, confirming that herbicides are present as racemates., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Three putative resistant Amaranthus retroflexus L. populations were collected in Heilongjiang province in China. Whole plant bioassays indicated high resistance (RI > 10) to imazethapyr in the three populations. In vitro acetolactate synthase (ALS) assays revealed that ALS from populations H3, H17 and H39 was less sensitive to imazethapyr inhibition compared to the susceptible population H76. The half-maximal inhibitory concentration (I50) values for H3, H17 and H39 were 14.83, 15.27 and 268 times greater, respectively, than that of the susceptible population H76. Three nucleotide mutations resulted in three known resistance-endowing amino acid substitutions, Ala-205-Val, Trp-574-Leu and Ser-653-Thr in the three resistant populations respectively. Therefore, ALS target-site mutations in resistant A. retroflexus could be responsible for imazethapyr resistance., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Plant growth and development are strongly affected by environmental pollutants, such as herbicides. Widely used herbicides can remain in soil or aquatic systems for long periods of time. Herbicide pollutants have been reported to heavily affect global plant growth and pose a significant challenge to agriculture. However, it is unclear whether herbicides affect plant flowering. Here, we demonstrated that imazethapyr (IM), a chiral herbicide, can enantioselectively promote flowering in Arabidopsis thaliana. We clarified the possible mechanism by which IM promotes flowering and found that the photoperiod pathway may play an important role in propagating the IM stress signal. IM enantiomers decreased the amplitude of core oscillators (CIRCADIAN CLOCK ASSOCIATED 1 and LATE ELONGATED HYPOCOTYL) and utilized the up-regulation of the GIGANTEA-(CONSTANS)-FLOWERING LOCUS T pathway to induce floral gene, APETALA1 over-expression enantioselectively; this treatment ultimately caused early flowering. Our findings provide new insight into the method by which plants control reproductive timing in response to herbicide stress. Flowering time is an important trait in crops and affects the life cycles of pollinator species. The persistence of herbicides in the biosphere will alter plant life cycles and diversity., (Copyright © 2013 Elsevier GmbH. All rights reserved.)

Brassica carinata A. Braun (carinata) has become an important oil crop for biofuel production in subtropical regions. Carinata is highly sensitive to acetolactate synthase (ALS)‐inhibiting herbicides, limiting its introduction into existing crop rotations. The objective of the study was to develop carinata lines resistant to ALS‐inhibiting herbicides. A susceptible carinata line was crossed with a resistant Brassica napus L. line. Lines derived from those crosses were screened at high doses of imidazolinones, which allowed identifying five lines with high levels of resistance. Doses to reduce plant growth 50% (GR50) and cause 50% injury (ID50) were four to nine times greater than susceptible lines. Resistant lines exhibited cross resistance with halosulfuron (sulfonylurea). Resistance was confirmed under field conditions with doses 2X and 4X for imazethapyr and 4X–8X for halosulfuron of their respective label doses. While susceptible lines died, resistant lines exhibited no injury or growth reductions compared with nontreated controls. Sequencing of the ALS gene indicated that all resistant lines carried a Trp574Leu amino acid substitution, a mutation responsible for resistance in other species. Crosses between resistant lines and a susceptible line demonstrated that the inheritance of the mutation corresponded with the resistance phenotype in the F2. The resistance trait behaved as a single, fully dominant allele, which makes it easier to transfer it to carinata lines with desirable agronomic traits. The resistant lines developed here provide flexibility for use in multiple crop rotations and opens the possibility to use ALS‐inhibiting herbicides for weed control within this crop's growing season. [ABSTRACT FROM AUTHOR]

Weedy rice is the most challenging weed species to remove in rice production. We found a novel phenotype of seedling leaves which rapidly generates necrotic spots in response to imidazolinone herbicides in weedy rice, but its influencing factors and formation basis are still unknown. In this study, we used the leaf necrotic spot-producing type of weedy rice as the material. First, leaf necrotic spots were defined as physiological and vacuole-mediated cell necrosis by microscopic examination. The imazethapyr concentration was positively correlated with the degree of necrotic spots occurring, while the action site was in accordance with necrosis using herbicide stability tests combined with fluorescence parameters. Furthermore, transcriptome analysis revealed significant differences in the gene expression of endoplasmic reticulum stress and the lipid metabolism membrane structure damage pathway during necrosis, as confirmed by transmission electron microscopy. The light–temperature test also showed that high temperature and intense light could promote the appearance of necrotic spots. These experimental results are helpful in clarifying the process and basis of imazethapyr in inducing the rapid generation of necrotic spots in rice leaves and providing new insight into understanding the mechanism of response to imidazolinone herbicides and the control of weedy rice. [ABSTRACT FROM AUTHOR]

Background: Weeds are one of the major constraints in achieving yield potential of black gram. Due to slow initial growth of black gram, weeds compete effectively and caused reduction in growth as well as yield of black gram. Hand weeding is neither practicable nor economical due to unpredictability of weather and high labour cost, respectively. Therefore, application of herbicides is considered as the best approach for efficient weed control in black gram. Method: A field experiment was conducted at Research Farm of Department of Agronomy, CCSHAU, Hisar during summer and kharif 2017 to evaluate the effect of different weed control treatments in black gram and their residual effect on succeeding pearl millet and sorghum crops. Total of fourteen weed control treatments were replicated thrice in randomized complete block design (RCBD). Result: Dactyloctenium aegyptium (37%), Trianthema portulacastrum (34%), Cyperus rotundus (21%) and Digera arvensis (8%) were the major weed flora associated with black gram at 30 DAS. Both at 30 and 60 DAS, PE application of imazethapyr + pendimethalin (RM) at 1000 g ha-1 provided 100% control of D. aegyptium and T. portulacastrum. PE application of imazethapyr + pendimethalin (RM) at 1000 g ha-1 was the most significant herbicide treatment (90% control of weeds) at 30 DAS however, 3-4 leaf stage application of imazethapyr + imazamox at 70 g/ha recorded with highest control of weeds (89%) at 60 DAS. Maximum seed yield (912 kg ha-1) and yield attributes of black gram were obtained in weed free treatment which was statistically at par with two hoeing performed at 20 and 40 DAS (895 kg ha-1) and PE application of imazethapyr + pendimethalin (RM) at 1000 g ha-1 (878 kg ha-1). Imazethapyr and its RM combination with imazamox applied at 3-4 leaf stage had phytotoxic effects on black gram at 30 DAS which suppressed the growth and caused yield penalty. Residual effect or phytotoxicity was not observed on succeeding pearl millet and sorghum crops. [ABSTRACT FROM AUTHOR]

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

Compacted soils may be negatively affecting the selectivity of herbicides applied in preemergence in the soybean crop. Therefore, the present work aimed to investigate possible negative effects on the morphophysiological characters of soybean plants, as well as on the agronomic and yield performances of this crop. For this purpose, two trials were carried out, one in a greenhouse and the other under field conditions. In a greenhouse, the study was carried out in a completely randomized design in a 2 × 8 factorial, with five replications, while in the field, the design used was randomized blocks, with the treatments arranged in split-plot (2 × 8), with six repetitions. The first factor/plot corresponded to the physical condition of the soil: compacted or not compacted, while the second factor/subplot was constituted by the application of preemergence herbicides: clomazone, diclosulam, flumioxazin, S-metolachlor, [imazethapyr + flumioxazin], [pyroxasulfone + flumioxazin], and [sulfentrazone + diuron], plus a control without herbicide. In the greenhouse study, there was a significant interaction between soil compaction and herbicides applied in preemergence for the relative index of chlorophyll b and root dry mass. Furthermore, the isolated herbicide factor did not promote significant changes in any of the morphophysiological variables evaluated. Compaction alone had a negative impact on the variables relative index of chlorophyll a and carbon assimilation rate, with reductions in the values of these variables when the soybean was submitted to growth in compacted soil. For the field experiment, there were no significant interactions between the factors for any of the analyzed variables, nor the effect of herbicides alone. The isolated soil compaction factor negatively impacted the plant stand and the thousand-grain mass of soybean, showing reductions in the values of this parameter when the soybean was grown in compacted soil. [ABSTRACT FROM AUTHOR]

In the mid‐southern United States, rice (Oryza sativa L.) is flooded primarily to suppress weed germination and growth. Two experiments were conducted to determine whether herbicide performance in conventional or Clearfield rice weed control programs was affected by intermittent flooding. The effects of flooding and herbicide program on barnyardgrass [Echinochloa crus‐galli (L.) P. Beauv] control, rice grain yield, and water applied were investigated at the Delta Research and Extension Center in Stoneville, MS, on Sharkey clay (very fine, smectitic, thermic Chromic Epiaquert). For herbicides commonly applied in conventional (clomazone, quinclorac, pendimethalin, thiobencarb, fenoxaprop‐ethyl, cyhalofop‐butyl, and bisypriboac sodium) or Clearfield rice weed control programs (imazethapyr plus bispyribac‐sodium followed by imazethapyr, imazamox or bispyribac‐sodium), intermittent flooding had no adverse effect on barnyardgrass control relative to a continuous flood. Moreover, initiating irrigation when the perched water table drops to 8 inches below the soil surface had no effect on rice grain yield and reduced water applied by 51%. Mid‐southern US rice producers can capture the water‐saving benefits of intermittent flooding while having no adverse effects on herbicide activity or crop productivity in conventional and Clearfield systems. Core Ideas: Barnyardgrass control did not differ between intermittently and continuously flooded systems.Initiating irrigation when perched water table drops 8 inches below soil surface had no effect on rice grain yield.Intermittent flooding reduced water applied 51% compared to continuous flooding. [ABSTRACT FROM AUTHOR]

Effectively controlling target organisms while reducing the adverse effects of pesticides on non-target organisms is a crucial scientific inquiry and challenge in pesticide ecotoxicology research. Here, we studied the alleviation of herbicide (R)-imazethapyr [(R)-IM] to non-target plant wheat by active regulation between auxin and secondary metabolite 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazine-3(4H)-one (DIMBOA). We found (R)-IM reduced 32.4% auxin content in wheat leaves and induced 40.7% DIMBOA accumulation compared to the control group, which effortlessly disrupted the balance between wheat growth and defense. Transcriptomic results indicated that restoration of the auxin level in plants promoted the up-regulation of growth-related genes and the accumulation of DIMBOA up-regulated the expression of defense-related genes. Auxin and DIMBOA alleviated herbicide stress primarily through effects in the two directions of wheat growth and defense, respectively. Additionally, as a common precursor of auxin and DIMBOA, indole adopted a combined growth and defense strategy in response to (R)-IM toxicity, i.e., restoring growth development and enhancing the defense system. Future regulation of auxin and DIMBOA levels in plants may be possible through appropriate methods, thus regulating the plant growth-defense balance under herbicide stress. Our insight into the interference mechanism of herbicides to the plant growth-defense system will facilitate the design of improved strategies for herbicide detoxification. [ABSTRACT FROM AUTHOR]

Amaranthus tuberculatus (waterhemp) is a pervasive weed of the Mid‐west and ‐south United States and is not native to North Carolina but infestations in crop fields have been reported recently. Amaranthus tuberculatus has evolved resistance to seven herbicide groups and multiple herbicide‐resistant populations are common where the species is native. The reported A. tuberculatus infestations in North Carolina have not been controlled with herbicides but no formal herbicide resistance characterisation has been conducted to date. Glasshouse dose–response experiments were conducted to determine the susceptibility of a population collected from Surry County, North Carolina to commonly applied postemergence herbicides compared to a herbicide‐susceptible population collected from Story County, Iowa. The Surry County population survived labelled rates of imazethapyr, atrazine, glyphosate, fomesafen, and mesotrione; the Story County population was controlled with these herbicides. Further, 2,4‐D, dicamba, and glufosinate effectively controlled the Surry and Story County populations. Molecular sequencing assays were subsequently conducted to determine if altered target sites facilitated resistance in the acetolactate synthase (ALS), 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS), photosystem II (psbA), and protoporphyrinogen oxidase (PPX2) genes. The Surry County population carried a Trp574Leu and ∆Gly210 mutations in the ALS and PPX2 gene, respectively. No mutations that would confer resistance were found in the EPSPS or psbA gene for either population. The results of both experiments provide evidence that a five‐way herbicide‐resistant A. tuberculatus population has encroached North Carolina. More research is needed to determine the mechanisms of resistance to atrazine, glyphosate, and mesotrione. [ABSTRACT FROM AUTHOR]

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

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

Among the factors that limit the productive potential of soybean crops, stands out lodging, in addition to competition with weeds. Given this, the importance of soybean pre-emergence herbicides for different purposes is highlighted; however, they have to be evaluated for selectivity. This study aimed to evaluate the growth and agronomic performance of soybean applied with pre-emergence herbicides. Experiment 1 was conducted in the 2017-2018 season at two locations, and experiment 2 in the 2016-2017 season at one location. Treatments consisted of the application of pre-emergence herbicides in soybean in a randomized block design with four replications. Crop injury and chlorophyll indices (experiment 1) and variables related to agronomic performance (experiments 1 and 2) were assessed. Diclosulam and chlorimuron showed potential for application at pre-emergence to reduce plant height and consequently plant lodging. Moreover, diclosulam, chlorimuron, sulfentrazone, flumioxazin, s-metolachlor, pendimethalin, trifluralin, imazethapyr/flumioxazin, and oxyfluorfen did not negatively affect agronomic performance when applied at pre-emergence of soybean. This study evidenced the selectivity of pre-emergence herbicides to soybean. [ABSTRACT FROM AUTHOR]

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

The evolution of herbicide-resistant weeds is the major challenge for chemical management worldwide, increasing production costs, and reducing yield. This work aimed to evaluate the putative resistance of the Amaranthus hybridus population from Candido Mota (CMT) to glyphosate and imazethapyr and to investigate the non-target site mechanisms involved. Dose–response studies were conducted under greenhouse conditions and the control and biomass reduction were evaluated 28 days after application (DAA). Absorption, translocation, and metabolization studies were evaluated at 72 h after treatment (HAT) using radiometric techniques. The dose–response results show different responses among populations to glyphosate and imazethapyr. The CMT population was not controlled with labeled herbicide doses. Based on biomass reduction, the resistance factor was 16.4 and 9.4 to glyphosate and imazethapyr, respectively. The CMT absorbed 66% of 14C-glyphosate and 23% of 14C-imazethapyr at 72 HAT. Although the CMT population absorbed more glyphosate than the susceptible population (12.6%), translocation was impaired for both herbicides in the CMT when compared to the SUS population. There was no evidence that herbicide metabolization was involved in CMT resistance to the herbicides studied. Understanding the mechanisms endowing resistance allows better decision-making. This is the first study that describes non-target-site resistance mechanisms in an Amaranthus hybridus population from Brazil. [ABSTRACT FROM AUTHOR]

Chicory (Cichorium intybus) is a commercially cultivated root crop in many countries of the world. Weeds have a depressing effect on the growth and development of root chicory. There are currently no herbicides registered for use on chicory in the Russian Federation. The objective of this work was to identify potential herbicides for controlling a broad range of weed species under the soil and climatic conditions of the Russian Federation. For the field experiment, herbicides were selected according to: (1) previous studies in USA, EU and South Africa; (2) the spectrum of weeds controlled; and (3) the probability of crop damage. All the herbicides used were registered in Russia for the control of certain weeds in other crops. Crop biomass, damage, and weed control were assessed to identify suitable herbicides. The results suggested that the best weed control herbicides would be a Zeta, SC (100 g/L imazethapyr) and Paradox, SC (120 g/L imazamox). These herbicides controlled, on average, 80% or more of the dicotyledonous weeds such as lamb's quarters (Chenopodium album), field pennycress (Thlaspi arvense), and sow thistles (Sonchus spp.). Since these herbicides do not reduce chicory biomass, they can be considered for registration or use on chicory. [ABSTRACT FROM AUTHOR]

Nowadays, large areas of agricultural land are contaminated with chemical plant-protection products. Agricultural soils are also susceptible to oil pollution as a result of accidents on oil pipelines. Bioremediation of such soils from oil with the help of hydrocarbon-oxidizing bacteria is hindered by the presence of additional pollutants such as herbicides. In this work, seven strains of Pseudomonas were isolated and identified, which showed differences in ability of oil biodegradation (32.7–77.3%). All strains showed resistance to herbicides based on 2,4-D and substances from the class of imidazolinones, possessed phosphate-solubilizing and nitrogen-fixing activity, and produced indolyl-3-acetic acid (305–1627 ng/mL culture liquid). They stimulated the growth of barley and clover in soil with oil, as well as the growth of clover in soil with herbicide. In a vegetative experiment (duration 30 days, initial oil content in soil 2% wt., herbicide based on imazethapyr 0.002% wt.) of barley plants and P. alcaligenes UOM 10 or P. frederiksbergensis UOM 11, oil degradation was 48.1–52.7%, the same strains and clover plants, 37.9–38.6%. The studied bacteria have the potential to be used in the bioremediation of oil-contaminated agricultural soils, including in combination with phytomeliorant plants. [ABSTRACT FROM AUTHOR]

Background: Groundnut encounters severe infestation of weed especially during the early stages of growth due to less crop canopy which allows higher weeds growth and thus crop becomes more susceptible to weed competition. During rainy season, effective and economical weed control is not possible through manual and mechanical weeding due to unfavorable soil conditions and also the unavailability of costly labours. Herbicides have been accepted as cost effective tool to manage weed menace in groundnut. The current study aims to study the efficancy of different post-emergence and pre-mix combination of post-emergence herbicides on weeds, growth and yield of groundnut. Methods: The field experiment was conducted at AICRP Weed Management Field, Department of Agronomy, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola (M.S.) during three consecutive Kharif seasons of 2015-2017. The experiment was laid out in randomized block design with ten treatments replicated thrice. The treatments comprised of one pre emergence and five different post emergence herbicides and compared with weed free and weedy check. Result: The results revealed that weed free was found most effective to control weeds in groundnut with lowest weed count, weed dry matter of weeds and maximum gross monetary returns (Rs. 117641/ha), net monetary returns (Rs. 80894/ha). Among the herbicides, application of Imazethapyr + Imazomox 0.10 kg/ha POE 20 DAS produced less weed count and weed dry matter and highest weed control efficiency (80.68%) and lower weed index (6.71%) as well as maximum growth, yield attributes and pod yield in groundnut over all the other herbicidal treatments viz. plant height (30.25), dry matter accumulation (18.11 g), number of pods/plant (32.35) and pod yield (2448 kg/ha) and highest pooled B:C ratio (3.74). [ABSTRACT FROM AUTHOR]

[Objectives] The paper was to systematically study the technology of weed control in alfalfa field. [Methods] Reviving alfalfa field and newly sown alfalfa field after emergence were selected, and the effects of different herbicides on weed control and alfalfa yield were discussed. [Results] The optimal herbicides after alfalfa reviving were 5% imazethapyr and 10% imazethapyr, and the optimal dosages were 1.5 and 1.05 L/hm2, respectively. The optimal herbicides after emergence of newly born alfalfa were 5% imazethapyr and 10% imazethapyr, and the optimal dosages were 1.5 and 0.75 L/hm2, respectively. [Conclusions] This study will provide a technical support for high quality production of alfalfa. [ABSTRACT FROM AUTHOR]

Imazethapyr, a post-emergent herbicide used in worldwide soybean and corn crops, induces genetic and biochemical alterations in aquatic vertebrates. This study examined the relationship between biomarkers at different organization levels and imazethapyr real-life route exposure in Boana pulchella adults. Frogs were exposed to imazethapyr-based formulation Pivot® H (10.59%) at concentrations representing possible acute routes: field runoff (S1:10 mg.L−1), exposure after direct foliar application (S2:100 mg.L−1) and during direct foliar application (S3:1000 mg.L−1). Post-exposure, endpoints levels were evaluated: organism alterations, biochemical activities and cytogenetic assays. Forty-eight hours post-exposure, antioxidant enzymes decrease, micronuclei induction and DNA damage were observed in all scenarios, while cholinesterase activity increase and body condition reduction were observed in frog-exposed to S3. Ninety-six hours post-exposure, frogs showed glutathione-S-transferase inhibition in S1, micronuclei induction in S2 and S3, and DNA-damage increase in S3. Herbicides routes of exposures in real-life could indicate that authorized applications have a risk to amphibian populations. [ABSTRACT FROM AUTHOR]

Assessing the adaptability and stability of herbicide-tolerant lentil accessions to two broad-spectrum post-emergence herbicides in multi-environment trials has become a must in a breeding program to improve its selection. The adaptability and stability of 42 herbicide-tolerant lentil accessions were investigated using five stability parameters under eight different environments. Significant Genotype–Environment (GE) interaction was found for days to flowering (DFLR), days to maturity (DMAT), and seed yield per plant (SY). The analyzed stability parameters such as Cultivar superiority, Finlay–Wilkinson, Shukla, Static Stability, and Wricke's Ecovalence ranked the tested accessions differently, confirming the importance of using a combination of stability parameters when evaluating the performance of a group of accessions. GGE biplot of the SY trait accounted for 60.79% of sums of squares of the GE interaction and showed that cool and high rainfall environments are ideal for testing the agronomic performance of tolerant accessions. The GGE biplot of SY showed that IG4605(19), IG195(6), and IG156635(12) were specifically adapted to one mega environment, whereas IG70056(38) was identified as a superior line having a high and stable yield. These lines should be included in lentil crossing programs to develop herbicide-tolerant cultivars adapted to diverse environments. [ABSTRACT FROM AUTHOR]

The genetic improvement of soybean cultivars over the years has focused on increasing the yield potential and tolerance to some abiotic and biotic factors. However, during the transfer of genes of interest, some genes responsible for a lower tolerance to herbicides can be integrated into the genome of the new cultivar. Thus, the objective of this study was to evaluate the selectivity of herbicide associations applied in the postemergence period of three soybean cultivars. The experiment was conducted in a randomized completely block design, with four replications. The selected cultivars were M7110 IPRO®, Foco IPRO®, and Bônus IPRO®. The herbicides and the respective doses (g a.i. ha-1) used were glyphosate (1176), glyphosate + bentazon (1176 + 600), glyphosate + fomesafen (1176 + 175), glyphosate + lactofen (1176 + 120), glyphosate + imazethapyr (1176 + 100), glyphosate + chlorimuron (1176 + 10), glyphosate + cloransulam (1176 + 39.5), and a control without herbicide application. The visual note of intoxication was evaluated for each treatment. The components of growth and yield evaluated were height, stand, weight of one hundred grains, and yield. The application of postherbicide herbicides did not alter the plant stands of soybean cultivars. Additionally, these herbicides did not reduce the yield of the M7110 IPRO® and Foco IPRO® cultivars. Glyphosate isolated and in association with lactofen or imazethapyr reduced the grain yield of the Bônus IPRO® cultivar. [ABSTRACT FROM AUTHOR]

Weeds result in a significant yield loss in mungbean (Vigna radiata [L.] R. Wilczek). However, post‐emergence (POST) herbicides are limited in mungbean for broad‐spectrum weed control. Therefore, we evaluated the efficacies of different herbicides in mungbean to find a suitable broad‐spectrum POST herbicide. Nine herbicides, weed‐free check, and unweeded control treatments were tested in a randomised block design with three replications for two consecutive years. Among the tested herbicides, clodinafop‐propargyl + sodium‐acifluorfen 122.5 g a.i. ha−1 applied at 15 days after sowing (DAS) reduced the broad‐leaved weed dry weight at 35 DAS and harvest by 55.8% and by 58.6% (p < 0.05) compared with the unweeded control respectively. Notably, it minimised the total weed dry weight by 23.1%–30.3% compared with the recommended herbicide pendimethalin 1 kg a.i. ha−1 – quizalopfop‐p‐ethyl 100 g a.i. ha−1 (p ≤ 0.05). Clodinafop‐propargyl + sodium‐acifluorfen had higher weed control index (58.2% at 35 DAS and 62.1% at harvest) over the remaining tested herbicides. Unweeded controls resulted in 51% yield loss compared with the clodinafop‐propargyl + sodium‐acifluorfen that did not differ from pendimethalin − quizalofop‐p‐ethyl for seed yield of mungbean. Decreasing order of treatment efficacy on mean grain yield across two years comprised the weed‐free check, clodinafop‐propargyl + sodium‐acifluorfen and pendimethalin − quiza‐lofop‐p‐ethyl, imazethapyr + imazamox, tembotrione, and topramezone. [Correction added on 10 November 2022, after first online publication: In the preceding sentence, changes have been made to the article content to improve clarity in this version.] Application of clodinafop‐propargyl + sodium‐acifluorfen led to the greatest increase in soil microbial biomass carbon, indicating higher levels of soil biological and rhizospheric activity. We suggest that clodinafop‐propargyl + sodium acifluorfen is a suitable broad‐spectrum option for weed management of mungbean. [ABSTRACT FROM AUTHOR]

Resistance to ALS-inhibiting herbicides has dramatically increased worldwide due to the persisting evolution of target site mutations that reduce the affinity between the herbicide and the target. We evaluated the effect of the well-known ALS Asp-376-Glu target site mutation on different imidazolinone herbicides, including imazamox and imazethapyr. Greenhouse dose response experiments indicate that the Amaranthus retroflexus biotype carrying Asp-376-Glu was fully controlled by applying the field recommended dose of imazamox, whereas it displayed high level of resistance to imazethapyr. Likewise, Sorghum halepense , carrying Asp-376-Glu showed resistance to field recommended doses of imazethapyr but not of imazamox. Biochemical inhibition and kinetic characterization of the Asp-376-Glu mutant enzyme heterologously expressed using different plant sequence backbones, indicate that the Asp-376-Glu shows high level of insensitivity to imazethapyr but not to imazamox , corroborating the greenhouse results. Docking simulations revealed that imazamox can still inhibit the Asp-376-Glu mutant enzyme through a chalcogen interaction between the oxygen of the ligand and the sulfur atom of the ALS Met200, while imazethapyr does not create such interaction. These results explain the different sensitivity of the Asp-376-Glu mutation towards imidazolinone herbicides, thus providing novel information that can be exploited for defining stewardship guidelines to manage fields infested by weeds harboring the Asp-376-Glu mutation. [Display omitted] • different imidazolinones caused similar response in ALS 376-mutants of A. retroflexus and S. halepense. • Higher resistance level to imazethapyr was observed with respect to imazamox. • In vitro ALS enzyme activity confirmed the in vivo dose-response results. • Docking and structure-activity relationships of isoforms revealed the causal features. [ABSTRACT FROM AUTHOR]