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Industrial hemp (Cannabis sativa) production is complex, with strict regulatory constraints and challenges associated with a lack of labeled pesticides due to its status as a novel crop in the US. Four experiments were conducted in 2020 and 2021 to establish herbicide tolerances for hemp production in the coastal plain of Georgia, USA. Objectives included evaluating hemp response to pretransplant or posttransplant herbicides, determining if planting method influenced herbicide injury from residual preplant applied herbicides, and understanding how plastic mulch may influence hemp flower yields. When applied one day prior to transplanting, maximum hemp crop visual injury was less than 12% compared to the untreated control, with acetochlor, flumioxazin, fomesafen, pendimethalin, and norflurazon while dithiopyr, halosulfuron, isoxaben, and isoxaflutole resulted in greater than 50% injury. Posttransplant applications of S-metolachlor, acetochlor, pendimethalin, and clethodim resulted in less than 15% injury while halosulfuron, metribuzin, trifloxysulfuron, imazethapyr, and prometryn applications resulted in greater than 50% injury to plants. Preplant and posttransplant applied herbicides were found to have little effect on total tetrahydrocannabinol (THC), cannabidiol (CBD), or total cannabinoids in the dry flower after harvest. In a separate experiment, injury from halosulfuron and metribuzin was 52% to 56% less when planted with a mechanical transplanter as compared to the practice of using a transplant wheel to depress a hole in the soil followed by hand transplanting. In the final experiment, hemp dry flower yield in a non-plastic mulched (bareground) system was similar to that in a plastic mulched system. However, early season plant above-ground biomass was less in the plastic mulched system, which may have been due to elevated soil temperatures inhibiting early season growth. [ABSTRACT FROM AUTHOR]

Field dodder (Cuscuta campestris yuncker) is an important parasitic weed that has negative impacts on the growth and yield of alfalfa (Medicago sativa L.). Effective control of field dodder in alfalfa crops is necessary to reduce yield losses. Field studies were conducted to evaluate the efficacy of various herbicides on field dodder in a new-seeded alfalfa crop at three locations (Karaj, Jiroft, and Urmia) in Iran during 2020–2021. The herbicides evaluated were imazethapyr (100 g a.i. ha−1), glyphosate (six doses ranging from 143 to 348 g a.i. ha−1 + ammonium sulfate at 8 kg ha−1), and propyzamide (1250, 1500, and 1750 g a.i. ha−1). The results demonstrated that propyzamide at 1750 g a.i. ha−1 provided complete control of field dodder in terms of percentage change in biomass at first (100%) and second (99%) cuttings of alfalfa in Urmia. The imazethapyr at 100 g a.i. ha−1 provided 96 and 87% control at the first and second cuttings, respectively, whereas propyzamide at 1750 g a.i. ha−1 showed the best efficacy in increasing alfalfa biomass at the first (up to 82%) and the second cuttings (up to 81%), depending on the location. Glyphosate provided reasonable control of the field dodder at the first (73%) and the second cutting (82%). However, at higher rates (307 and 348 g a.i. ha−1), it caused significant reductions in alfalfa biomass due to crop injury, especially at the first cutting. The use of propyzamide at 1750 g a.i. ha−1 is recommended for highly effective control of field dodder in alfalfa crops without compromising the crop yield. [ABSTRACT FROM AUTHOR]

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. [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]

IntroductionWeeds are one of the most problematic factors in chickpea production systems and chemical control of weeds is limited in Iran because of registered selective herbicides for this crop are not available for farmers. In this situation, optimizing of herbicide application (especially soil-applied herbicides) is one way that can help farmers to combat with weeds. Incorporated By Sowing (IBS) is one of the best way for optimizing of non-selective soil herbicides application in crops. The purpose of this experiment is to investigate the possibility application of non-selective soil-applied herbicides in directed planting of chickpea via IBS. Material and MethodsApplication possibility of non-selective herbicides in directed sowing of chickpea was evaluated in Ardabil and Zanjan in 2020. The treatments were arranged in a strip plot experiment with randomized complete block design and 3 replications. The vertical factor was herbicide application (including: trifluralin, metribuzin, pendimethalin, imazethapyr, and their combination with (phenmedipham+desmedipham+ethofumesate), and also oxyfluorfen and weedy and weed free controls. Horizontal factor was incorporated by sowing (IBS) methods (including: incorporate by seed planter and cultivator+seed planter). Seed germination of chickpea, weed density and biomass and chickpea grain yield were evaluated 30 days after herbicide application and in the end of chickpea growth. Results and DiscussionIBS methods did not have a significant impact on weed and chickpea density and biomass. Therefore, the use of a cultivator before seed planting is only recommended when the seedbed is inadequately prepared or if pre-planting weed control has not been effectively executed. In contrast, herbicides had significant effects on weeds population and chickpea in experimental locations. In Ardabil, pendimetalin and pendimetalin + (phenmedipham + desmedipham + ethofumesate) were the only treatments that had low efficacy on weeds (with 48.9 and 51.7 % weed biomass reduction respectively) and other treatments had no significant difference in 30 days after herbicides application. In the end of growing season, the highest weeds biomass reduction (in compared with control) were recorded in trifluralin, metribuzin and imazethapyr in combination with (phenmedipham + desmedipham + ethofumesate) and oxyfluorfen (with 84, 83, 80 and 70 of control (%) respectively). In Zanjan, single application of trifluralin and metribuzin and their combination with (phenmedipham + desmedipham + ethofumesate) and combination of imazethapyr with (phenmedipham + desmedipham + ethofumesate) had the highest weed control with 79, 71, 78.6 and 75.5 % respectively. In contrast with Ardabil, the lowest weed control efficacy was recorded in oxyfluorfen plots (22.4%). Grain yield of chickpea was also high in trifluralin + (phenmedipham + desmedipham + ethofumesate) and was low in imazethapyr in Zanjan and Ardabil. ConclusionsApplication of soil herbicides (including: Metribuzin and Trifluralin) in chickpea is possible only if, farmers use them just before sowing and incorporate the herbicides into the seedbed during the sowing process.

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. [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]

Introduction Weeds are one of the most problematic factors in chickpea production systems and chemical control of weeds is limited in Iran because of registered selective herbicides for this crop are not available for farmers. In this situation, optimizing of herbicide application (especially soil-applied herbicides) is one way that can help farmers to combat with weeds. Incorporated By Sowing (IBS) is one of the best way for optimizing of non-selective soil herbicides application in crops. The purpose of this experiment is to investigate the possibility application of non-selective soil-applied herbicides in directed planting of chickpea via IBS. Material and Methods Application possibility of non-selective herbicides in directed sowing of chickpea was evaluated in Ardabil and Zanjan in 2020. The treatments were arranged in a strip plot experiment with randomized complete block design and 3 replications. The vertical factor was herbicide application (including: trifluralin, metribuzin, pendimethalin, imazethapyr, and their combination with (phenmedipham+desmedipham+ethofumesate), and also oxyfluorfen and weedy and weed free controls. Horizontal factor was incorporated by sowing (IBS) methods (including: incorporate by seed planter and cultivator+seed planter). Seed germination of chickpea, weed density and biomass and chickpea grain yield were evaluated 30 days after herbicide application and in the end of chickpea growth. Results and Discussion IBS methods did not have a significant impact on weed and chickpea density and biomass. Therefore, the use of a cultivator before seed planting is only recommended when the seedbed is inadequately prepared or if pre-planting weed control has not been effectively executed. In contrast, herbicides had significant effects on weeds population and chickpea in experimental locations. In Ardabil, pendimetalin and pendimetalin + (phenmedipham + desmedipham + ethofumesate) were the only treatments that had low efficacy on weeds (with 48.9 and 51.7 % weed biomass reduction respectively) and other treatments had no significant difference in 30 days after herbicides application. In the end of growing season, the highest weeds biomass reduction (in compared with control) were recorded in trifluralin, metribuzin and imazethapyr in combination with (phenmedipham + desmedipham + ethofumesate) and oxyfluorfen (with 84, 83, 80 and 70 of control (%) respectively). In Zanjan, single application of trifluralin and metribuzin and their combination with (phenmedipham + desmedipham + ethofumesate) and combination of imazethapyr with (phenmedipham + desmedipham + ethofumesate) had the highest weed control with 79, 71, 78.6 and 75.5 % respectively. In contrast with Ardabil, the lowest weed control efficacy was recorded in oxyfluorfen plots (22.4%). Grain yield of chickpea was also high in trifluralin + (phenmedipham + desmedipham + ethofumesate) and was low in imazethapyr in Zanjan and Ardabil. Conclusions Application of soil herbicides (including: Metribuzin and Trifluralin) in chickpea is possible only if, farmers use them just before sowing and incorporate the herbicides into the seedbed during the sowing process. [ABSTRACT FROM AUTHOR]

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.

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]

IntroductionRain-fed Lentil (Lens culinaris Medik.) is vulnerable to weed competition because of its tiny stature, slow establishment, and limited vegetative growth. Weed control is necessary for maximum seed yield and seed quality. Crop yield losses are primarily a result of competition with weeds for nutrients, moisture and space. Therefore, weed control at this period plays an important role to gain high roduction. Although the vast majority of lentil production is under rain-fed conditions, there is a little published information on weed control with herbicides in rain-fed lentils. Herbicides due to efficiency and expense savings play a essential role in weed control. The purpose of this research was to determine the best time to application effective herbicides in weeds control for the maximum rain-fed Lentil production in Khorramabad. Materials and MethodsThe Lentil (Lens culinaris Medik.) field experiment was carried out as split plot based on complete randomized block design with three replications during 2017-2018 in Khorramabad (48.21°E, 33.29°N, 1170 m above sea level, 450 mm average yearly precipitation) Iran. The following herbicides were used: Oxyfluorfen (EC 24%) 1 Li ha-1, Isoxaflutole (SC 480) 200 Ml ha-1, Flumetsulam(WG 800) 20 g ha-1, Metribuzin (WP 70%) 500g ha-1, Pendimethalin Aria(EC33%) 4 li ha-1, Pendimethalin Prowl (CS45.5%) 4li ha-1, Imazethapyr (SL10%) 350 ml ha-1 and Pendimethalin prowl 2li ha-1plus Imazethapyr 350 ml ha-1. Herbicide applicatioin time at 3 levels; IAP application (Immediately after planting), PRE application and IBCE (eraly post herbicide application at fourth lentil node stage) was assigned to the main and sub plots respectively. The fields were in wheat cultivation in the year before the experiments. The soil at the test sites was a silty loam with a pH of 7.9 and organic matter of 1.11%. Lentil was sown at a density of 75 kg seed ha-1 by hand on December 21, 2017. Herbicides were sprayed with an electric knapsack sprayer MATABI (calibrated to deliver 300 L ha-1. In order to evaluate the effect of treatments on weeds density and biomass, at the beginning of lentil flowering, sampling was done from a surface of 0.3 m-2 area and weed density and weed biomass recorded. At lentil physiological maturity, the yield and yield components were measured by harvesting lentil plants from a 1-m2 area in each plot (Izadi & Maghsoudi, 1400). The data were subjected to the analysis of variance using SAS. Means were compared using Duncan's Multiple Range test at P=0.05 level of significance. Results and DiscussionThe results indicated that the lowest weed density and weed biomass were associated with Flumetsulam and Prowl plus Imazethapyr. The average weed densities for the postemergence and preemergence treatments of the eight evaluated herbicides were 14.9% and 31.0% lower, respectively, compared to the herbicide application immediately after planting. The least herbicide injury effects on the Lentil crop were assigned to the Pendimethalin Aria, Pendimethalin Prowl, Prowl plus Imazethapyr, Imazethapyr and Flumetsulam. In the case of Oxyfluorfen herbicide, weed density for early postemergence application treatment was 84.1% lower than in PRE application. In the case of Isoxaflutole herbicide, the mean weed density for application immediately after planting was 79.3% lower than for early post-application. In the case of Flumetsulam herbicide, the mean of weed biomass for application immediately after planting was 73.3% and 66.6% less than preemergence and early post-application, respectively. With the exception of Flumetsulam herbicide, there was no significant difference between the different herbicide application times in terms of weed biomass. The highest average Lentil grain yield per unit area was observed when Flumetsulam herbicide was applied immediately after planting. On the other hand, the lowest average Lentil grain yield per unit area was recorded when Isoxaflutole herbicide was applied immediately after planting. No significant differences in Lentil grain yield per unit area were found between the different application times for the herbicides Metribuzin and Imazethapyr. Based on cluster analysis grouping of relative efficacy of control treatments, immediately after planting application or preemergence application of Flumetsulam and early postemergence application of Imazethapyr were better than the other herbicide treatments for Lentil weed control, whereas the lowest relative efficacy was related to preemergence application of Oxyfluorfen, immediately after planting application of Isoxaflutole and Metribuzin, and preemergence application of Pendimethalin Arya. ConclusionBased on the results of this research, the application of flumezolam immediately after planting (20 g ha-1) and imazatapir( 350 ml ha-1) as pre-emergence application have had more efficiency for weed control in lentil than other herbicide treatments, while the pre-emergent application of oxyfluorfen, the application immediately after planting of isoxaflotel and metribyozin have had the effects of plant burning on lentil crops and the pendimethalin Aria herbicide is not recommended in lentil farms because of to the lack of control of broadleaf weeds under normal conditions in lentil fields. In general, among the experimental treatments, in terms of the level of control efficiency and the level of safety for the lentil crop, the application of flumetsulam immediately after planting was the best herbicide treatment.

A bioassay study was conducted to determine the differences in the susceptibility of selected crops to simulated imazethapyr residues based on morphological and anatomical parameters. Sugar beet, white mustard, and rapeseed oil were found to be the most sensitive based on ED50 values for the root length and the root fresh weight. Corn and sunflower were less sensitive, and wheat was the least sensitive. The measured anatomical parameters confirmed the different sensitivities of the tested plants, as evidenced by a shortening of the meristem and elongation zones, a reduction in the distance between the root tip and the absorption zone, and the distance between the root tip and the point where the primordium of the lateral root appears. An imazethapyr residue level equivalent to ED20 (for root length) did not cause serious morphological changes in the less sensitive plants, nor did it cause significant changes in the length of the root cap, the beginning of the root absorption zone (root hair region), the beginning of lateral root formation (i.e., the permanent region), and the number of root primordia per root length. Therefore, ED20 could be proposed as an acceptable residue level (ARL) or herbicide residue level at which these plants can be safely sown. [ABSTRACT FROM AUTHOR]

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]

Introduction Rain-fed Lentil (Lens culinaris Medik.) is vulnerable to weed competition because of its tiny stature, slow establishment, and limited vegetative growth. Weed control is necessary for maximum seed yield and seed quality. Crop yield losses are primarily a result of competition with weeds for nutrients, moisture and space. Therefore, weed control at this period plays an important role to gain high roduction. Although the vast majority of lentil production is under rain-fed conditions, there is a little published information on weed control with herbicides in rain-fed lentils. Herbicides due to efficiency and expense savings play a essential role in weed control. The purpose of this research was to determine the best time to application effective herbicides in weeds control for the maximum rain-fed Lentil production in Khorramabad. Materials and Methods The Lentil (Lens culinaris Medik.) field experiment was carried out as split plot based on complete randomized block design with three replications during 2017-2018 in Khorramabad (48.21°E, 33.29°N, 1170 m above sea level, 450 mm average yearly precipitation) Iran. The following herbicides were used: Oxyfluorfen (EC 24%) 1 Li ha-1, Isoxaflutole (SC 480) 200 Ml ha-1, Flumetsulam(WG 800) 20 g ha-1, Metribuzin (WP 70%) 500g ha-1, Pendimethalin Aria(EC33%) 4 li ha-1, Pendimethalin Prowl (CS45.5%) 4li ha-1, Imazethapyr (SL10%) 350 ml ha-1 and Pendimethalin prowl 2li ha-1plus Imazethapyr 350 ml ha-1. Herbicide applicatioin time at 3 levels; IAP application (Immediately after planting), PRE application and IBCE (eraly post herbicide application at fourth lentil node stage) was assigned to the main and sub plots respectively. The fields were in wheat cultivation in the year before the experiments. The soil at the test sites was a silty loam with a pH of 7.9 and organic matter of 1.11%. Lentil was sown at a density of 75 kg seed ha-1 by hand on December 21, 2017. Herbicides were sprayed with an electric knapsack sprayer MATABI (calibrated to deliver 300 L ha-1. In order to evaluate the effect of treatments on weeds density and biomass, at the beginning of lentil flowering, sampling was done from a surface of 0.3 m-2 area and weed density and weed biomass recorded. At lentil physiological maturity, the yield and yield components were measured by harvesting lentil plants from a 1-m2 area in each plot (Izadi & Maghsoudi, 1400). The data were subjected to the analysis of variance using SAS. Means were compared using Duncan's Multiple Range test at P=0.05 level of significance. Results and Discussion The results indicated that the lowest weed density and weed biomass were associated with Flumetsulam and Prowl plus Imazethapyr. The average weed densities for the postemergence and preemergence treatments of the eight evaluated herbicides were 14.9% and 31.0% lower, respectively, compared to the herbicide application immediately after planting. The least herbicide injury effects on the Lentil crop were assigned to the Pendimethalin Aria, Pendimethalin Prowl, Prowl plus Imazethapyr, Imazethapyr and Flumetsulam. In the case of Oxyfluorfen herbicide, weed density for early postemergence application treatment was 84.1% lower than in PRE application. In the case of Isoxaflutole herbicide, the mean weed density for application immediately after planting was 79.3% lower than for early post-application. In the case of Flumetsulam herbicide, the mean of weed biomass for application immediately after planting was 73.3% and 66.6% less than preemergence and early post-application, respectively. With the exception of Flumetsulam herbicide, there was no significant difference between the different herbicide application times in terms of weed biomass. The highest average Lentil grain yield per unit area was observed when Flumetsulam herbicide was applied immediately after planting. On the other hand, the lowest average Lentil grain yield per unit area was recorded when Isoxaflutole herbicide was applied immediately after planting. No significant differences in Lentil grain yield per unit area were found between the different application times for the herbicides Metribuzin and Imazethapyr. Based on cluster analysis grouping of relative efficacy of control treatments, immediately after planting application or preemergence application of Flumetsulam and early postemergence application of Imazethapyr were better than the other herbicide treatments for Lentil weed control, whereas the lowest relative efficacy was related to preemergence application of Oxyfluorfen, immediately after planting application of Isoxaflutole and Metribuzin, and preemergence application of Pendimethalin Arya. Conclusion Based on the results of this research, the application of flumezolam immediately after planting (20 g ha-1) and imazatapir(350 ml ha-1) as pre-emergence application have had more efficiency for weed control in lentil than other herbicide treatments, while the pre-emergent application of oxyfluorfen, the application immediately after planting of isoxaflotel and metribyozin have had the effects of plant burning on lentil crops and the pendimethalin Aria herbicide is not recommended in lentil farms because of to the lack of control of broadleaf weeds under normal conditions in lentil fields. In general, among the experimental treatments, in terms of the level of control efficiency and the level of safety for the lentil crop, the application of flumetsulam immediately after planting was the best herbicide treatment. [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]

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]

Introduction: Atwo-year researchtrialwas conductedto evaluate progressionof common bean (Phaseolus vulgaris) growth, Rhizoctonia root rot and weed development in association with productivity when treated with different cultivars, planting dates and weed controlmethods in north-western part of Iran. Methods: To determine the best descriptors, six standard curves were examined to model development of bean dry matter, Rhizoctonia root rot incidence, and weed density during two growing seasons across 256 field plots. Exponential and linear-by-linear models were fitted to bean-disease-weed progression data, and then model parameters representing over-season progress curve elements were used in multivariate regression analyses to estimate bean production. Results and discussion: Furthermore, using herbicides (Imazethapyr and Trifluralin) restricted weed density by 28% in early (mid-spring) and 42% in late (late spring to early summer) plantings. Late plantings of two bean cultivars decreased disease progress up to 36% for herbicide use, hand-weeding and control. Although bean dry matter, pod and seed production for herbicide use and hand-weeding treatments were 6-17% greater than control, late planting improved productivity in control by 10-24%. Findings suggested that late planting of bean improved efficiency of herbicides to control weeds. Late planting also restricted Rhizoctonia root rot progress and thus, improved bean yield. There were significant correlations between bean-disease-weed development descriptors. According to principal component analysis, beandisease-productivity-weed variables accounted for 80% of total data variance. Such information extends our understanding of bean-disease-weed progress in interaction with planting date to develop more effective and sustainable integrated Rhizoctonia management programs. [ABSTRACT FROM AUTHOR]

Silene conoidea L. is an annual troublesome broadleaf weed in winter wheat fields in China. In recent years, field applications of tribenuron-methyl have been ineffective in controlling S. conoidea in Hebei Province, China. The aim of this study was to determine the molecular basis of tribenuron-methyl resistance in S. conoidea. Whole-plant response assays revealed that the resistant population (R) exhibited a higher level of resistance (382.3-fold) to tribenuron-methyl. The R population also showed high cross-resistance to other acetolactate synthase (ALS) inhibitors, including imazethapyr, bispyribac-sodium and florasulam. However, the R population could be controlled by the field-recommended rates of bentazone, MCPA, fluroxypyr, carfentrazone-ethyl and bromoxynil. In vitro ALS activity assays indicated that the tribenuron-methyl I50 value for the R population was 18.5 times higher than those for the susceptible population (S). ALS gene sequencing revealed an amino acid mutation, Trp-574-Leu, in the R population. Pretreatment with the P450 inhibitor malathion indicated that the R population might have cytochrome P450-mediated metabolic resistance. These results suggest that the Trp-574-Leu mutation and P450-mediated enhanced metabolism coexist in S. conoidea to generate tribenuron-methyl resistance. This is the first time that target-site and non-target-site resistance to tribenuron-methyl has been reported in S. conoidea. [ABSTRACT FROM AUTHOR]

Beckmannia syzigachne is a noxious grassy weed that infests wheat fields in China. Previously, we identified that mesosulfuron-methyl resistance in a B. syzigachne population (R, SD04) was conferred by non-target resistance, such as cytochrome P450 mixed-function oxidases (P450s)-based metabolism. RNA sequencing and real-time PCR (qRT-PCR) were used to discover potential P450s-resistant-related genes. Five cytochrome P450s (CYP704A177, CYP96B84, CYP71D7, CYP93A1, and CYP99A44) were found to be highly expressed in R plants. In this study, CYP99A44 and CYP704A177 were cloned from B. syzigachne and transferred into Arabidopsis thaliana to test the sensitivity of Arabidopsis with and without P450s genes to mesosulfuron-methyl and other acetolactate synthase (ALS)-inhibiting herbicides. Transgenic Arabidopsis overexpressing CYP99A44 became resistant to the sulfonylurea herbicide mesosulfuron-methyl, but showed no resistance to pyroxsulam, imazethapyr, flucarbazone, and bispyribac-sodium. Notably, those overexpressing CYP704A177 showed resistance to pyroxsulam and bispyribac-sodium, but not to mesosulfuron-methyl, imazethapyr, and flucarbazone. These results indicated that B. syzigachne and transgenic Arabidopsis displayed different cross-resistance patterns to ALS-inhibiting herbicides. Subcellular localization revealed that CYP99A44 and CYP704A177 protein were located in the endoplasmic reticulum. Furthermore, these results clearly indicated that CYP99A44-mediated mesosulfuron-methyl resistance in B. syzigachne and CYP704A177 may be involved in B. syzigachne cross-resistance to pyroxsulam and bispyribac-sodium. [ABSTRACT FROM AUTHOR]

Black-grass (Alopecurus myosuroides Huds.) is a common weed in Chinese wheat fields, and has become troublesome due to its evolution of herbicide resistance. One black-grass population (HN-14) collected from a wheat field where herbicides were applied was suspected to be resistant (R) to mesosulfuron-methyl. This study aims to establish a cross-resistance pattern and explore potential resistance mechanisms. The results of a whole-plant dose response assay showed that the resistant (R) population had a high of resistance to mesosulfuron-methyl (33-fold); meanwhile, no synergism of P450s activity inhibitor malathion was observed. The sequencing results revealed that ALS resistance mutation Trp-574-Leu occurred in R plants. The results of in vitro ALS enzyme activity assays also supported that the extractable ALS from R plants were 23.22-fold resistant to mesosulfuron-methyl. In the light of the "R" resistance rating system, HN-14 has evolved RRR and RR resistance to fenoxaprop-P-ethyl, clodinafop-propargyl, haloxyfop-methyl, and fluazifop-P-butyl and R? (resistance may be developing) to pinoxaden, however remains sensitive to imazethapyr, quizalofop-P-ethyl, tralkoxydim, and isoproturon. These results indicated that the mesosulfuron-methyl resistance in the black-grass population HN-14 was driven by a target-site mechanism rather than a nontarget (at least P450s-mediated) mechanism. [ABSTRACT FROM AUTHOR]

Green pigweed [Amaranthus powellii S. Wats.] is a competitive, annual, broadleaf weed that can significantly reduce soybean yield due to rapid early growth and biomass production. As a consequence of green pigweed's high competitiveness with crops, the weed species is generally managed with the use of herbicides; this may, however, lead to the selection of resistance. A green pigweed biotype with resistance to MCPA, mecoprop, dichlorprop-p, aminocyclopyrachlor (synthetic auxins), and imazethapyr (acetolactate synthase-(ALS)-inhibitor) was recently confirmed in Ontario, Canada. Research was conducted to identify alternative effective preemergence (PRE) and postemergence (POST) herbicides for the control of multiple-herbicide-resistant (MHR) green pigweed in Ontario soybean production. Four field trials, two with PRE and two with POST herbicides were conducted near Dresden, Ontario in 2019 and 2020. Visible soybean injury, green pigweed control, density, aboveground biomass, and soybean yield were evaluated following application with 19 PRE herbicide treatments and 12 POST herbicide treatments in separate studies. At 8 wk after application (WAA), pyroxasulfone/flumioxazin applied PRE controlled green pigweed 95% and was the most effective soil-applied herbicide. In the POST study, glyphosate was the most effective herbicide, controlling green pigweed 94% at 8 WAA. Imazethapyr, applied PRE or POST did not control this green pigweed biotype as it is also resistant to ALS-inhibitors. Control with other ALS-inhibiting herbicides as well as with PPO-inhibiting herbicides was variable, and further research is needed to determine the reason for variable control with these herbicides. [ABSTRACT FROM AUTHOR]

The application of flumioxazin and imazethapyr can affect the interactions between rhizobia and soybean in the rhizosphere. However, it remains unclear the effect of both herbicides, even when applied in mixture, on early nodulation and biological N fixation (BNF) in soybean, mainly related to some important biochemical traits in nodules. This study assessed the effect of flumioxazin, imazethapyr and their mixture on early nodulation and BNF in rhizosphere of soybean. The plant emergence, early nodulation, growth, and N accumulation were evaluated in soybean grown in sandy and clayey soils. The leghemoglobin content and glutamine synthetase (GS) activity were also assessed in fresh nodules. Individually, flumioxazin and imazethapyr did not affect the plant emergence, nodulation and N accumulation in soybean, while the mixture decreased significantly these parameters. Also, the values of leghemoglobin content and GS activity did not decrease with the application of the herbicides individually. The application of herbicides imazethapyr and flumioxazin separately negatively influenced the growth of soybean, while they do not influence the nodulation and N accumulation. However, the use of these herbicides in mixture can negatively influence the early nodulation and N fixation by native rhizobia. [ABSTRACT FROM AUTHOR]

Yield reduction in lentil crop due to weed infestation is a key hindrance to its growth due to poor weed-crop competition. Imazethapyr (IM), a selective herbicide, target acetolactate synthase (ALS) which catalyzes the first reaction in biosynthesis of branched chain amino acids, required for plant growth and development. The objective of the present study was to investigate the impact of IM treatment on weeds, ALS enzyme activity, antioxidant capacity, osmolyte accumulation, growth and yield related parameters in lentil genotypes. Two IM tolerant (LL1397 and LL1612) and two susceptible (FLIP2004-7L and PL07) lentil genotypes were cultivated under weed free, weedy check and IM treatments. Weed control efficiency reached its peak at 21 days after spray (DAS). Imazethapyr treatment decreased chlorophyll and carotenoid content up to 28 DAS with higher reduction in susceptible genotypes. FLIP2004-7L and PL07 had reduced plant height and lower number of pods under IM treatment which resulted in decreased seed yield. Higher ALS activity in LL1397 and LL1612 at 21 DAS, higher antioxidant capacity and glycine betaine content both at 21 and 28 DAS and lower decrease in relative leaf water content might be mediating herbicide tolerance in these genotypes that led to higher seed yield. The identified IM tolerance mechanism can be used to impart herbicide resistance in lentil. [ABSTRACT FROM AUTHOR]

A bioassay study was conducted to determine the differences in the susceptibility of selected crops to simulated imazethapyr residues based on morphological and anatomical parameters. Sugar beet, white mustard, and rapeseed oil were found to be the most sensitive based on ED50 values for the root length and the root fresh weight. Corn and sunflower were less sensitive, and wheat was the least sensitive. The measured anatomical parameters confirmed the different sensitivities of the tested plants, as evidenced by a shortening of the meristem and elongation zones, a reduction in the distance between the root tip and the absorption zone, and the distance between the root tip and the point where the primordium of the lateral root appears. An imazethapyr residue level equivalent to ED20 (for root length) did not cause serious morphological changes in the less sensitive plants, nor did it cause significant changes in the length of the root cap, the beginning of the root absorption zone (root hair region), the beginning of lateral root formation (i.e., the permanent region), and the number of root primordia per root length. Therefore, ED20 could be proposed as an acceptable residue level (ARL) or herbicide residue level at which these plants can be safely sown.

The aim of this study was to evaluate the efficacy of sequentially applied herbicides to control Conyza sumatrensis, one of the most widely distributed weeds worldwide, in soybean pre-sowing burndown. The study was conducted under field conditions in the state of Paraná, Brazil, at 2018-2019 growing season. The experiment consisted of a randomized block design with four replicates, with 12 treatments consisting of different herbicide mixtures applied before sowing. Control of C. sumatrensis, injury to soybean plants, and variables related to agronomic performance were evaluated. The control levels were high for all treatments, except for the one that was free of saflufenacil in either of the two applications. These results highlight the importance of saflufenacil in the control of C. sumatrensis and show promise for the use of saflufenacil/imazethapyr when considering the system and other weeds. All studied treatments were selective to soybean, which showed higher injury values in the presence of diclosulam; however, this did not compromise the agronomic performance of soybean. [ABSTRACT FROM AUTHOR]

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In order to determine the best time to use and the adequate dose of four herbicides to control weeds in dryland chickpea (Cicer arietinum L.) fields, we performed the present experiment in 4 x 5 m plots. Fourteen treatments were carried out that from 1 to 9 included trifluralin. Treatments 1, 2, and 3 were with increasing doses of trifluralin (480, 720, and 960 g ai ha-1) applied 30 days before planting. Treatments 4, 5, and 6 included increasing doses of trifluralin (480, 720, and 960 g ai ha-1) applied 15 days before planting. Treatments 7, 8 and 9 consisted of increasing doses of trifluralin (480, 720, and 960 g ai ha-1) applied at the time of planting. Treatments 10, 11, and 12 included pyroxasulfone (85 g ai ha-1), flumioxazin (51 g ai ha-1) and imazethapyr (100 g ai ha-1), respectively. These last three treatments were carried out at the time of planting; treatments 13 and 14 were: weed-infested (without weed control) and weed-free (manual weeding during the entire season). Flumioxazin 66% and pyroxasulfone 57% (mean of two samples) reduced weed dry weight compared to uncontrolled treatment. The results showed that the treatments were significantly different for 100-seed weight, biological yield, and seed yield of chickpea. Weed-infested and weed-free plants had the lowest and highest grain yield, respectively. Herbicide treatments of flumioxazin, trifluralin 960 g ai ha-1, and pyroxasulfone at planting produced 55%, 44%, and 40% higher grain yield than the weed-infested plots. Also, none of the herbicide treatments reduced chickpea yield and biomass. The herbicide residues had no adverse effect on wheat growth in the next crop season.

Amaranthus hybridus is a C4 broadleaf species widely spread across Brazilian agricultural territory. Recently, several herbicide resistance reports have been documented in southern Brazil, including the reports for enolpyruvilshikymate-3-phosphate (EPSPS)- and acetolactate-synthase (ALS)-inhibitors. The objective of this study was to confirm the existence of an ALS resistant (R) A. hybridus population from Paraná state. Dose-response experiments were conducted with R and a known susceptible (S) population with herbicides from three different chemical groups of ALS inhibitors. Biomass relative to untreated control was quantified and GR50 (dose for 50% of biomass reduction), GR90 (dose for 90% of biomass reduction) and resistant index (RI) were calculated based on non-linear regression analysis. The R population was 6.9-fold resistant to chlorimuron-ethyl and 6.5-fold resistant to metsulfuron-ethyl (sulfonylureas - SUL). Additionally, the recommended rates from each herbicide was not sufficient to reach 90% control to R based on GR90 parameter estimation. There was no resistance to imazethapyr (imidazolinone - IMI) and cloransulan-methyl (triazolopyrimidine - TRI) due to the low doses of GR90 and non-significant RIs. The R A. hybridus population investigated was resistant to ALS inhibitors chlorimuron-ethyl and metsulfuron-ethyl (SUL), but susceptible to IMI and TRI herbicides. [ABSTRACT FROM AUTHOR]

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A field experiment was conducted at Coconut Research Station, Balaramapuram, Kerala during Kharif 2019 (June to September) to arrive at a cost-effective weed management practice for bush type cowpea. The experiment was conducted in RBD with seedbed preparation as first factor and weed management practices as second factor. Seedbed preparation comprised of stale seedbed and normal seed bed and weed management practices comprised of dried banana leaf mulch alone @ 10 t ha-1, dried banana leaf mulch @ 10 t ha-1 followed by (fb) post emergence application of imazethapyr orquizalofop-p-ethyl @ 50 g ha-1 at 25 DAS, pre-emergence application of diclosulam @ 12.5 g ha-1 fb quizalofop-p-ethyl @ 50 g ha-1 or hand weeding at 25 DAS, hand weeding at 20 and 40 DAS and weed check. The results revealed that pod yield of bush type cowpea reduced by70 per cent due to weed infestation. Stale seedbed significantlyreduced the total weed density and dry weight and recorded higher pod yield compared to normal seedbed. Among the weed management practices, mulching with dried banana leaf @ 10 t ha-1 followed by quizalofop-p-ethyl application (50 g ha-1) at 25 DAS recorded the lowest weed dry weight (3.77 g m-2), the highest weed control efficiency (93%), pod yield (7589 kg ha-1) and B:C ratio (1.71). Pre-emergence application of diclosulam fb application of quizal of op-p-ethyl at 25 DAS recoded higher WCE than hand weeding twice but recorded lesser yield. Among the treatment combinations, stale seedbed or normal seedbed + dried banana leaf mulching @ 10 t ha-1 fb quizalofop-p-ethyl@ 50 g ha-1 at 25 DAS recorded higher pod yield and B:C ratio (7731.7 kg ha-1 and 1.72 and 7446.3 kg ha-1 and 1.70, respectively) with a WCE of 95 and 91 per cent. [ABSTRACT FROM AUTHOR]

Select herbicides with different mechanism of action is a satisfactory option for resistant weed control. Then, the present work aimed to study the efficiency of different herbicides and their mixtures on Bidens pilosa (blackjack) and Euphorbia heterophylla (wild poinsettia) biotypes, resistant to ALS herbicides in two development stages. The trials we arranged in a completely randomized design with four replications. The treatments tested were (g a.i/a.e ha-1): imazethapyr at 70 and 140 (WG formulation) + 1.0% Assist; imazethapyr at 57.6 and 72 (SL formulation) + 1.0% Assist; imazapic + imazethapyr at 56 and 70 + 1.0% Assist; glyphosate + imazethapyr (596); saflufenacil + glyphosate at 35 + 720 + 0.5% Dash in tank mix, glyphosate at 720 and, a control without herbicide application. Control efficiency was evaluated, as well as dry matter accumulation at the end of the studies. Plants of both species were more susceptible to herbicides at the early stage of development (2 to 4 leaves). The treatments with saflufenacil + glyphosate, (imazethapyr + glyphosate) and glyphosate promoted the best controls, regardless of the species studied and the application stage. The mixture with saflufenacil provided the highest control speed, and the mixture (imazethapyr + glyphosate) was less efficient among three excellent treatments when applied to plants in the 4-6 leaf stage. The treatments (imazethapyr, in both formulations) and (imazethapyr + imazapic) were ineffective in controlling the studied biotypes, regardless of dose and developmental stage studied. [ABSTRACT FROM AUTHOR]

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To evaluate the effect of time and rates of imazethapyr application on weed control of bean field an experiment was conducted in Agricultural Research Station of Lorestan University based on the randomized complete block design (RCBD) with three replications in 2015-2016. In this experiment, the effects of pre planting, pre emergence and post emergence applications of imazethapyr with different rates (0.25, 0.5, 0.75 and 1 lit.ha-1) and pre planting imazethapyr mixed with soil (1 lit.ha-1) plus post emergence with weed control in two levels (control and non- control) was studied. The most important weed species in the experimental site were safflower (Carthamus oxyacantha), catchweed bedstraw (Galium tricornutum), wild mustard (Sinapis arvensis), cow cockle (Vaccaria grandiflora), chickweed (Conringia orientalis). Weed density in weedy control condition was estimated to be 133 plants.m-2. The results showed the maximum percentage of weed dry weight loss, as compared to not controlling weed due to imazetapir post-treatment application of 0.75 and 1 L.ha-1, was 86.95%. Also highest average root length (12.46 cm), root dry weight (95 g), number of branches (5.33), number of seeds per pod (9.3) and seed yield were observed in hand weeding. The highest plant height (88.33 cm) belonged to weed control treatment, the highest LAI (2.59) in herbicide usage, in pre planting (0.25 lit.ha-1), the highest average number of pod per plant (10 pod), number of pod per m-2 (100 pod) and biological yield (33367.1 kg.ha-1) resulted from pre emergence herbicide application (0.5 lit.ha-1). The highest of 100 seed weight (109.6 g) for pre planting herbicide application (1 lit.ha-1) plus herbicide post emergence application (1 lit.ha-1) was seen. The results also showed that, after hand weeding, the best concentration of imazethapyr pre emergence application (0.5 lit.ha-1) that it could decrease weed density by 99% as compared to not controlling weed. This treatment (imazethapyr pre emergence application (0.5 lit.ha-1) was the best treatment. Higher concentrations of herbicides also decreased bean yield because of burning, reduction in leaf area and photosynthesis.

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.

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

Background: Setaria italica is the second-most widely planted species of millets in the world and an important model grain crop for the research of C4 photosynthesis and abiotic stress tolerance. Through three genomes assembly and annotation efforts, all genomes were based on next generation sequencing technology, which limited the genome continuity. Results: Here we report a high-quality whole-genome of new cultivar Huagu11, using single-molecule real-time sequencing and High-throughput chromosome conformation capture (Hi-C) mapping technologies. The total assembly size of the Huagu11 genome was 408.37 Mb with a scaffold N50 size of 45.89 Mb. Compared with the other three reported millet genomes based on the next generation sequencing technology, the Huagu11 genome had the highest genomic continuity. Intraspecies comparison showed about 94.97 and 94.66% of the Yugu1 and Huagu11 genomes, respectively, were able to be aligned as one-to-one blocks with four chromosome inversion. The Huagu11 genome contained approximately 19.43 Mb Presence/absence Variation (PAV) with 627 protein-coding transcripts, while Yugu1 genomes had 20.53 Mb PAV sequences encoding 737 proteins. Overall, 969,596 Single-nucleotide polymorphism (SNPs) and 156,282 insertion-deletion (InDels) were identified between these two genomes. The genome comparison between Huagu11 and Yugu1 should reflect the genetic identity and variation between the cultivars of foxtail millet to a certain extent. The Ser-626-Aln substitution in acetohydroxy acid synthase (AHAS) was found to be relative to the imazethapyr tolerance in Huagu11. Conclusions: A new improved high-quality reference genome sequence of Setaria italica was assembled, and intraspecies genome comparison determined the genetic identity and variation between the cultivars of foxtail millet. Based on the genome sequence, it was inferred that the Ser-626-Aln substitution in AHAS was responsible for the imazethapyr tolerance in Huagu11. The new improved reference genome of Setaria italica will promote the genic and genomic studies of this species and be beneficial for cultivar improvement. [ABSTRACT FROM AUTHOR]

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. [Display omitted] • A novel strain YN1 with strong imazethapyr degradation ability was characterized in vivo studies. • It is speculated that the intermediate and degradation pathway of imazethapyr in strain YN1 may involve degrading enzymes. • Immobilization technology can accelerate the degradation of imazethapyr in liquid culture medium and soil, and improve its environmental tolerance and storage stability. • Immobilized microbial inoculum can reduce the toxic effect of imazethapyr on sensitive crops. [ABSTRACT FROM AUTHOR]

Introduction Chickpea (Cicer arietinum L.) is an important food legume, is presently grown in more than 50 countries and imported by more than 150 countries. It is the second largest grown and produced food legume after dry beans. During 2011, chickpea was grown on 13.2 million ha and about 80% of this area was in south and southeast Asia (India 68%, Pakistan 8.9% and Myanmar 2.3%). The other major chickpea growing countries include Turkey, Australia, Ethiopia, Iran, Mexico, Canada and USA. Weeds are a serious constraint to increased production. Chickpea, however, is a poor competitor with weeds because of slow growth rate and limited leaf area development at early life stages. Weeds compete with chickpea plants for water, nutrients, sunlight and also harbor insect-pests and diseases. If the weeds are not controlled, they can significantly reduce chickpea yield. Significant yield losses (up to 84%) due to weeds have been reported in chickpea, and even more severely (up to 98%) in autumn-sown chickpea. Thus, weed management is crucial in chickpea to realize maximum yields and also to maintain high its quality. Because of the sensitivity of chickpea to herbicides, most effective are the pre-emergence herbicides, and choices for post-emergence herbicides are limited. The pre-emergence herbicides are effective in controlling weeds at early stage of seedling growth, but weeds germinating after crop emergence become dominant in the field and cause substantial yield loses. Therefore, chickpea cultivars with improved herbicide tolerance, which can offer greater flexibility for use of post-emergence herbicides, are required by the farmers. There are few reports on identification of herbicide tolerance in chickpea. However, these reports indicate presence of genotypic variations for herbicide tolerance in chickpea. This study was aimed to identify chickpea cultivars tolerance to pyridate, imazethapyr, foramsulforun and rimsolforun herbicides by screening. Materials & Methods In order to study chickpea cultivars toleration against some post-emergence herbicides, a pot experiment was carried out in a completely randomized design in four replications at research greenhouse Ferdowsi University of Mashhad. Factors included herbicides application in 4 levels (foramsulfuron, rimsulfuron, imazethapyr and Pyridate), herbicide dose in 3 levels (100 and 75% of the herbicides recommended dose for weed control with control treatment without of herbicide use) and chickpea cultivars in 5 levels, (Hashem, ILC 482, Kaka, Azad and Arman). Chickpea seeds were prepared from chickpea seed bank of Research Center for Plant Sciences, Ferdowsi University of Mashhad. Plants were in pots with 14 cm diameter and sprayed at 2nd true leaf of chickpea cultivars. To evaluate the effects of experimental results, survival and dry matter of chickpea cultivars were indicated, 2 and 4 weeks after herbicides spraying. Analysis of variance of data was carried out after their conversion to plant with MSTATC software and for means comparisons LSD (p≤0.05) test was used. Results & Discussion Based on the results, chickpea cultivars were not significantly different in terms of dry matter, but they had a different reaction to the herbicides application. It is indicated that foramsulfuron and rimsulfuron had the highest phytotoxicity and negative effects on chickpea; and the lowest negative impact was related to pyridate herbicide application. Also reduced dose of imazethapyr herbicide had no effect on chickpea cultivars. According to the results ILC 482 and Azad chickpea cultivars were the most tolerant and Arman cultivar was the most susceptible cultivars toward mentioned herbicides application, especially pyridate and imazethapyr. Conclusion According to this study, the effects of pyridate, imazethapyr, rimsulfuron and foramsulfuron herbicides in chickpea cultivars were different. The intensity of phytotoxicity effects of investigated herbicides were ranked as rimsulfuron > foramsulfuron> Imazethapyr> pyridate. So, use of rimsulfuron and foramsulfuron herbicides chickpea not recommended in chickpea weed control. The research findings will increase our awareness regarding chickpea tolerance to the above herbicides and provide guidelines for adjustment for minimizing crop injury.

Together, Conyza bonariensis, C. canadensis and C. sumatrensis show 105 reported cases of biotypes resistant to herbicides like glyphosate, paraquat, and acetolactate synthase (ALS) inhibitors. The application of pre-emergent herbicides combined with burndown herbicides is believed to be effective in controlling Conyza spp. during soybean pre-sowing management. The objective of this study was to evaluate the efficacy of sulfentrazone/diuron, imazethapyr/flumioxazin, and diclosulam in mixtures with diquat, paraquat, or glufosinate on the control of Conyza spp. Two field experiments were conducted in a randomized block design with four replicates. Treatments consisted of the application of pre-emergent plus burndown herbicides, besides the weedy control treatment (without application), for a total of 10 treatments. The control of Conyza spp. was evaluated at 7, 14, 21, 28, and 35 d after herbicide application, and symptoms of injury in soybean plants were evaluated at 14, 21, 28, and 35 d after herbicide application. The herbicides sulfentrazone/diuron, imazethapyr/flumioxazin, and diclosulam in combination with burndown herbicides diquat, paraquat, or glufosinate were effective in controlling Conyza spp. in the pre-sowing management of soybean, highlighting good options for pre- and post-emergent herbicide rotations. Mixtures with diclosulam showed a higher potential for injury to soybean plants than sulfentrazone/diuron and imazethapyr/flumioxazin.

The objective of the study was to evaluate the efficiency of herbicides use in the control of tough lovegrass according to the availability of solar radiation and the presence or absence of flooded. Two experiments were conducted in a completely randomized design, in a 2x2x4 and 2x2x5 factorial scheme, where factor A was equivalent to the environment (natural or reduced radiation); factor B to water condition (with a 2 cm flooded or without); and, factor C the herbicides: cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), cyhalofop butyl + glyphosate (315 g ha-1 + 1080 g ha-1) and control (without application) in the first experiment. In the second experiment, the herbicides used were cyhalofop butyl (315 g ha-1), glyphosate (1080 g ha-1), sethoxydim (184g ha-1), imazethapyr (106 g ha-1) and control (without application). Glyphosate efficiently controls plants of tough lovegrass with four tillers (>90%), being superior to cyhalofop, imazethapyr and sethoxydim; independently, of resource conditions. Reduction in the availability of solar radiation generates less shoot dry mass production from the weed, and improves the control only by imazethapyr and cyhalofop. In general, a flooded condition does not affect tough lovegrass control by herbicides. [ABSTRACT FROM AUTHOR]

Evolution of multiple herbicide resistance in Palmer amaranth across the United States is a serious challenge for its management. Recently, a Palmer amaranth population (KCTR; Kansas Conservation Tillage Resistant) from a long-term conservation tillage research project in Kansas, United States, was found uncontrolled by several commonly used herbicides. Importantly, this field did not have a history of repeated use of some of the herbicides for which the KCTR Palmer amaranth population showed lack of control. The objectives of this study were to confirm the evolution of multiple resistances and determine possible mechanism(s) of resistance in KCTR Palmer amaranth plants. In response to post-emergence application, 28–100% of KCTR Palmer amaranth survived field recommended rates of 2,4-D, ALS-, PS II-, EPSPS-, PPO-, HPPD-inhibitor herbicides, or tank- or pre-mixture of PS II- and HPPD-inhibitor herbicides, confirming evolution of six-way resistance in this Palmer amaranth population. However, this population was found susceptible to the PS I- and glutamine synthetase inhibitor herbicides. Chlorsulfuron-, imazethapyr-, and atrazine-resistant plants did not show any previously reported mutation in ALS and psbA genes, the target sites of these herbicides, respectively. However, the survivors of glyphosate treatment showed amplification of EPSPS gene (up to 88 copies). The KCTR plants pretreated with cytochrome P450 or GST inhibitors along with atrazine, 2,4-D, lactofen, or mesotrione had significantly less biomass accumulation than those treated with herbicides alone. Plants treated with P450 inhibitor followed by imazethapyr showed moderate reduction of biomass in KCTR which was statistically similar to a susceptible Palmer amaranth population treated with imazethapyr. These results suggest predominance of metabolic resistance possibly mediated by cytochrome P450 and GST enzyme activity that may have predisposed the KCTR Palmer amaranth population to evolve resistance to multiple herbicides. This is the first report of evolution of six-way resistance in a single Palmer amaranth population. Appropriate management strategies, including integration of cultural, and mechanical, and herbicide mixtures, are warranted to control such Palmer amaranth populations. [ABSTRACT FROM AUTHOR]

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