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In view of the widespread increase in herbicide-resistant weeds, biotechnology companies have developed dicamba-tolerant soybean and cotton cultivars. This technology can, however, increase the risk of the product drifting to adjacent areas. This study was developed with the objective of the to evaluate the phytotoxicity and biometric variables of young eucalyptus plants exposed to subdoses of the herbicide dicamba. The experiment was carried out under field conditions in Rio Verde, state of Goiás, Brazil. The treatments were represented by the application of 0 (control), 7.5, 15, 30, 60, 120 or 240 g ae ha-1 of dicamba 45 days after the seedlings were planted in the field. In terms of phytotoxicity, the dicamba doses of 120 and 240 g ae ha-1 caused greater damage to the eucalyptus plants in all periods of evaluation. The predominant symptoms were epinasty, increased number of shoots and necrosis and senescence of young branches and leaves. The herbicide doses of 120 and 240 g ae ha-1 significantly compromised plant height and diameter, number of branches and dry mass of leaves and roots, interfering with the growth and development of the eucalyptus crop. The results indicate that the effect of subdoses of the herbicide dicamba can interfere with the proper development of young eucalyptus plants, which may cause losses in the initial planting phase and future losses for producers. [ABSTRACT FROM AUTHOR]

Estimating the hydraulic properties of the vadose zone is essential to understand soil‐water dynamics and achieving appropriate water management in agricultural lands. Inverse modelling methods are commonly used to estimate hydraulic properties from field observations. Unlike the extensively applied local search methodologies, data assimilation techniques can fully account for multiple uncertainties and are becoming a widely used tool for estimating hydraulic parameters. However, only few applications on real field tests are available. The main objective of this study was to estimate the van Genuchten‐Mualem (VGM) parameters and the saturated hydraulic conductivity (Ks$$ {K}_s $$) of a heterogeneous low‐lying farmland at the margin of the Venice Lagoon, Italy, characterized by high peat content, sandy drifts, and a very shallow water table. To this end, two methods were tested, that is, the Ensemble Smoother (ES) and the Levenberg–Marquardt (LM) algorithm associated with hydrological modelling performed with Hydrus‐1D. Volumetric water content (VWC) observations were collected at three monitoring sites from May to September 2011. Results on parameters highlighted that the ES technique effectively reduced the uncertainty of α$$ \alpha $$ and n$$ n $$, but it was less effective on θr$$ {\theta}_r $$ and Ks$$ {K}_s $$. The results on VWC showed that the ES efficiency decreased with the increasing non‐linearity of the system (e.g., higher sand content) and when the variability of the experimental data was lower (e.g., deepest soil layers where saturation remained permanently close to 1). Both LM and ES allowed to reproduce the VWC observations in the calibration and validation phases, with the former and the latter performing better in the case of sandy and peat soils, respectively. As concerns the method applicability, the ES was less time‐demanding as it efficiently updated all the parameters at once and was less dependent on the user choices. Finally, the paper points out the importance of previous knowledge of the VGM parameters (e.g., from lab hydraulic analyses) in defining the constraints for the optimization. [ABSTRACT FROM AUTHOR]

The rapid adoption of dicamba (3,6‐dichloro‐2‐methoxybenzoic acid)‐resistant (DR) soybean [Glycine max (L.) Merr.] resulted in an increase of post‐emergent dicamba applications during the soybean‐growing season, resulting in off‐target movement and injury to non‐DR soybean. Field trials were established in Manhattan, KS, in 2018 and 2019 and in Ottawa, KS, in 2019 to characterize the response of non‐DR soybean to one, two, or three applications of reduced rates of dicamba at three application timings. Soybean were treated with 0.56, 1.12, and 5.6 g a.e. ha−1 of dicamba, which is equivalent to 1/1,000X, 1/500X, and 1/100X of a 1X field‐use rate (560 g a.e. ha−1), respectively. Soybean plants were treated at V3, R1, R3, V3 followed by (fb) R1, V3 fb R3, R1 fb R3, and V3 fb R1 fb R3 growth stages. Soybean injury from dicamba was less severe following application during the V3 than the R1 or R3 growth stages. In general soybean injury was the greatest 4 wk after application. The greatest soybean yield reduction (68%) followed dicamba applications of 5.6 g a.e. ha−1 at V3 fb R1 fb R3 in Manhattan, KS, 2018, where yield loss was generally greater and may be attributed to droughty conditions. Yield loss was minimal in Manhattan, KS, and Ottawa, KS, in 2019 following a single dicamba application at the V3 stage, regardless of application rate and following dicamba application at 0.56 g a.e. ha−1, regardless of number of applications. The greatest soybean yield losses from dicamba occurred with two or three applications at 1.12 or 5.6 g a.e. ha−1. Core ideas: Non‐DR soybean exposed to dicamba at R1 had greater injury and yield loss than those exposed at V3 or R3.Non‐DR soybean exposed to dicamba multiple times had persistent injury that was correlated with yield loss.Dicamba exposure resulted in minimal reduction of pods plant−1 and seed weight.Dicamba exposure had no effect on non‐dicamba resistant soybean offspring. [ABSTRACT FROM AUTHOR]

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The growing challenges of protecting biodiversity in agro-ecosystems and maintaining high agricultural productivity has become an important issue within the European Union, shaping both European and national agro-policies. The presented study is part of a broader evaluation of the interim targets of the 2013 Dutch policy plan on sustainable use of pesticides, carried out in 2019 by the PBL (Planbureau voor de Leefomgeving) Netherlands Environmental Assessment Agency. We aimed to assess the effectiveness of selected mitigation measures suggested in the policy plan on non-target terrestrial arthropods using a common carabid beetle Bembidion lampros as a model species. We combined dynamic landscape models with detailed agent-based population modelling to simulate impacts of reduction of toxicity of insecticides, reduction of spray drift to the off-crop area, and increase in area of field margins on the beetle population dynamics in ten agricultural landscapes representing different farming systems. Our simulations showed that a shift towards low-risk products should be the priority if the goal is to increase beetle range. To promote local beetle abundance this needs be coupled with increasing amount of field margins in a landscape. Overall, the observed treatment and landscape effects were highly context-specific and therefore we suggest that care is used when defining and interpretting metrics based on population effects of policy measures. This caveat notwithstanding, the use of simulation to assess complex interactions between landscape, ecology and behaviour of species, and policy measures can be a powerful tool supporting innovative policy management. This should include the development of landscape-context specific targets and/or mitigation measures. [ABSTRACT FROM AUTHOR]

Exploration of novel bio-based materials for value addition of textile substrates is a desirable research trend. In this context, vanillin (4-hydroxy-3-methoxybenzaldehyde), a bio-based material (obtained from vanilla pod) having multifunctional properties, can be a well-suited candidate. In the present article, both the vanillin alone and vanillin-copper (vanillin-Cu) complexes have been incorporated into cotton textiles separately using a high temperature-high pressure (HT-HP) dyeing machine and the quantity of copper has successfully been optimized to demonstrate enhanced properties. The vanillin-treated fabric has shown very good all-round properties like ultraviolet protection factor (UPF), color value (K/S value), and antibacterial activity (AM) in the presence of copper salt. However, only vanillin itself has rendered as such no UPF value but demonstrated 70% antimicrobial activity against E. coli (Gram-negative) bacteria and during washing operation small molecules of vanillin get leached out of fabric (as represented by significant loss in properties). This is the first time that the functional properties of vanillin and vanillin-Cu complex have directly been explored on cotton textile wherein significantly enhanced properties have been achieved on vanillin-Cu complex-treated fabric (i.e. 99% AM, a good UPF factor of 78, K/S value of 11.55, and even 25% antioxidant activity). [ABSTRACT FROM AUTHOR]

Background and Aims When plant communities are exposed to herbicide 'drift', wherein particles containing the active ingredient travel off-target, interspecific variation in resistance or tolerance may scale up to affect community dynamics. In turn, these alterations could threaten the diversity and stability of agro-ecosystems. We investigated the effects of herbicide drift on the growth and reproduction of 25 wild plant species to make predictions about the consequences of drift exposure on plant–plant interactions and the broader ecological community. Methods We exposed potted plants from species that commonly occur in agricultural areas to a drift-level dose of the widely used herbicide dicamba or a control solution in the glasshouse. We evaluated species-level variation in resistance and tolerance for vegetative and floral traits. We assessed community-level impacts of drift by comparing the species evenness and flowering networks of glasshouse synthetic communities comprised of drift-exposed and control plants. Key Results Species varied significantly in resistance and tolerance to dicamba drift: some were negatively impacted while others showed overcompensatory responses. Species also differed in the way they deployed flowers over time following drift exposure. While drift had negligible effects on community evenness based on vegetative biomass, it caused salient differences in the structure of co-flowering networks within communities. Drift reduced the degree and intensity of flowering overlap among species, altered the composition of groups of species that were more likely to co-flower with each other than with others and shifted species roles (e.g. from dominant to inferior floral producers, and vice versa). Conclusions These results demonstrate that even low levels of herbicide exposure can significantly alter plant growth and reproduction, particularly flowering phenology. If field-grown plants respond similarly, then these changes would probably impact plant–plant competitive dynamics and potentially plant–pollinator interactions occurring within plant communities at the agro-ecological interface. [ABSTRACT FROM AUTHOR]

The widespread adoption of genetically modified (GM) dicamba-tolerant (DT) soybean was followed by numerous reports of off-target dicamba damage and yield losses across most soybean-producing states. In this study, a subset of the USDA Soybean Germplasm Collection consisting of 382 genetically diverse soybean accessions originating from 15 countries was used to identify genomic regions associated with soybean response to off-target dicamba exposure. Accessions were genotyped with the SoySNP50K BeadChip and visually screened for damage in environments with prolonged exposure to off-target dicamba. Two models were implemented to detect significant marker-trait associations: the Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway (BLINK) and a model that allows the inclusion of population structure in interaction with the environment (G×E) to account for variable patterns of genotype responses in different environments. Most accessions (84%) showed a moderate response, either moderately tolerant or moderately susceptible, with approximately 8% showing tolerance and susceptibility. No differences in off-target dicamba damage were observed across maturity groups and centers of origin. Both models identified significant associations in regions of chromosomes 10 and 19. The BLINK model identified additional significant marker-trait associations on chromosomes 11, 14, and 18, while the G×E model identified another significant marker-trait association on chromosome 15. The significant SNPs identified by both models are located within candidate genes possessing annotated functions involving different phases of herbicide detoxification in plants. These results entertain the possibility of developing non-GM soybean cultivars with improved tolerance to off-target dicamba exposure and potentially other synthetic auxin herbicides. Identification of genetic sources of tolerance and genomic regions conferring higher tolerance to off-target dicamba may sustain and improve the production of other non-DT herbicide soybean production systems, including the growing niche markets of organic and conventional soybean. [ABSTRACT FROM AUTHOR]

Dicamba plus glyphosate (DpG) tank mixture has been widely adopted for broad-spectrum weed control. However, recent studies indicated antagonistic interactions between these herbicides. Furthermore, little is known about the effect of non-ammonium sulfate water conditioner (non-AMS WC) adjuvant on the activity of DpG tank mixture. Thus, the present study was elaborated to evaluate (1) the interaction of DpG tank mixtures combinations on barnyardgrass, and glyphosate-susceptible (GS) and -resistant (GR) horseweed control, and (2) the effect of non-ammonium sulfate water conditioner (non-AMS WC) on the interaction of those two herbicides on the aforementioned weed species. Greenhouse experiments were conducted in 2020 at the Pesticide Application Laboratory in North Platte, NE. Herbicide treatments were arranged in a two-level factorial design of six dicamba rates by six glyphosate rates for Study 1, and in a three-level factorial design of two adjuvant treatments (presence or not of non-AMS WC) by four dicamba rates by four glyphosate rates for Study 2. Both trials were conducted as randomized complete block designs with four replications and two runs. Antagonistic interactions were observed throughout DpG treatments in GS and GR horseweed. For instance, dicamba (560 g ae ha−1) and glyphosate (1260 g ae ha−1) resulted in 72% of GR horseweed biomass reduction, compared to 81% of estimated biomass reduction. For barnyardgrass, antagonistic interactions were only observed within the reduced glyphosate rates. The addition of non-AMS WC had no effect on DpG antagonism. However, it improved the barnyardgrass control by glyphosate. [ABSTRACT FROM AUTHOR]

The article examines evasions of U.S. state-created easements appropriate property owners' right to exclude dicamba particles and the accountability of U.S. states for taking offsite property owners' right to exclude others from their properties.

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing 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 reaction of plants to simultaneous stress action and treatment with biological stimulants still remains poorly studied. Laboratory and field experiments have been conducted to study the growth and yield of bread wheat (Triticum aestivum L.) of the variety Ekada 113; stress markers and quantitative ratios of phytohormones in plants under insufficient soil moisture; the effects of spraying with herbicide containing 2,4-D and dicamba and growth-stimulating bacterium Pseudomonas protegens DA1.2; and combinations of these factors. Under water shortage conditions, spraying plants with Chistalan reduced their growth compared to non-sprayed plants, which was associated with inhibition of root growth and a decrease in the content of endogenous auxins in the plants. Under conditions of combined stress, the treatment of plants with the strain P. protegens DA1.2 increased the IAA/ABA ratio and prevented inhibition of root growth by auxin-like herbicide, ensuring water absorption by the roots as well as increased transpiration. As a result, the content of malondialdehyde oxidative stress marker was reduced. Bacterization improved the water balance of wheat plants under arid field conditions. The addition of bacterium P. protegens DA1.2 to the herbicide Chistalan increased relative water content in wheat leaves by 11% compared to plants treated with herbicide alone. Application of the bacterial strain P. protegens DA1.2 increased the amount of harvested grain from 2.0–2.2 t/ha to 3.2–3.6 t/ha. Thus, auxin-like herbicide Chistalan and auxin-producing bacterium P. protegens DA1.2 may affect the balance of phytohormones in different ways. This could be the potential reason for the improvement in wheat plants' growth during dry periods when the bacterium P. protegens DA1.2 is included in mixtures for weed control. [ABSTRACT FROM AUTHOR]

Background: Many genotoxicity tests allow us to understand the mechanism of damages on genetic material occurring in living organisms against various physical and chemical agents. One of them is the Comet test. The current study aimed to evaluate genotoxic caused by picloram and dicamba to root meristems of Allium cepa utilizing comet assay. Methods: Two different protocols were used for rooting and auxin/pesticide application. (i) A. cepa bulbs were rooted in MS medium and then treated with Murashige and Skoog (MS) medium (control) and 0.67, 1.34, 2.01, 2.68, 3.35, 4.02, and 8.04 mg/L of picloram and dicamba using aseptic tissue culture techniques. (ii) A. cepa bulbs were then rooted in bidistilled water and treated with 0 (control), 0.67, 1.34, 2.01, 2.68, 3.35, 4.02, and 8.04 mg/L of picloram and dicamba in distilled water. The A. cepa root tip cells in both treatment groups were examined using comet test to find the possible DNA damaging effects of picloram and dicamba. Results: The results obtained at all the concentrations were statistically compared with their control groups. Almost at all the concentrations of Picloram and dicamba increased comet tail intensity (%) and tail moment in roots treated in MS medium. Two highest concentrations revealed toxic effect. On the other hand, DNA damaging effect of both auxins was only noted on the highest (> 4.02 mg/L) in roots treated in distilled water. Conclusions: This study approve and confirm genotoxic effects of how growth regulators on plants. These findings give an evidence of DNA damage in A. cepa. Therefore, both picloram and dicamba should only be used in appropriate and recommended concentrations in agriculture to conserve ecosystem and to pose minimum threat to life. [ABSTRACT FROM AUTHOR]

• Purple cauliflower had lower microspore embryogenesis than white and orange cauliflower. • Dicamba (0.5 µmol·L-1) enhanced microspore embryogenesis & plantlet regeneration in purple cauliflower. • The deep purple cauliflower DHP03 was superior to the donor plant in nutrient content. Cauliflower (Brassica oleracea var. botrytis L.) is an important vegetable grown worldwide. Colored cauliflower is highly desirable because of its aesthetic appearance and nutritional benefits. The use of isolated microspore culture technology to obtain doubled haploid (DH) lines could expedite breeding. However, the low frequency of microspore embryogenesis, particularly in colored cauliflowers, remains a major hurdle for the practical application of this technique. In this study, nine genotypes of cauliflower microspores were successfully induced among the 15 differently colored genotypes. The addition of 0.5 µmol·L−1 dicamba to NLN-13 medium increased the number of embryos per bud in purple cauliflower genotypes 20WY06, 20WY08, and 20WY10. The number of embryos was 4.64-, 5.45-, and 4.03-folds higher than that of the control, respectively. Meanwhile, 0.5 µmol·L−1 dicamba effectively promoted plantlet regeneration. The spontaneous diploidization rates of the purple cauliflower ranged from 52.63% to 54.76%, suggesting potential applicability in breeding without artificial doubling. A total of 76 purple cauliflower DH lines were generated. One DH line identified, DHP03, with high vitamin C and anthocyanin could be further applied to purple cauliflower breeding. This is the first study to utilize dicamba in improving the rate of microspore embryogenesis and plantlet regeneration, supply the DH lines in hybrid seeds, and shorten the breeding cycle of purple cauliflower. [ABSTRACT FROM AUTHOR]

The off-target loss of pesticide formulations caused by volatilization and leaching has reduced effective utilization and increased risks to the ecological environment and human health. Self-assembly of pesticides has been widely concerned due to the improved bioactivity and environmental compatibility. Herbicidal ionic liquids (HILs) could effectively decrease off-target loss and increase efficacy and environmental safety by improving the physicochemical properties of herbicides. Herein, HILs were prepared by pairing dicamba with quaternary ammonium salts containing different alkyl chain lengths and aromatic groups and subsequently self-assembled into spherical nanoparticles (HIL NPs) via electrostatic interaction and hydrophobic effect. Compared with dicamba, the obtained HIL NPs with an average particle size of 6–55 nm exhibited improved physicochemical properties, including high zeta potential values (+20.3 to +27.8 mV), low volatilization rate (2.4–3.9 %) and surface tension (22.83–33.07 mN m−1), decreased contact angle (32.25–41.55°) and leaching potential (76.2–86.5 %), and high soil adsorption (12.1–23.8 %), suggesting low risks to the environment. The control efficacy against Amaranthus retroflexus of HIL3 NPs pairing dicamba with octadecyl-trimethyl ammonium chloride was better than that of dicamba sodium salt at different concentrations. Therefore, the ionic liquid self-assembly developed by a facile and green preparation approach to reduce the volatility and leaching of pesticides would have enormous potential in sustainable agriculture. [Display omitted] • Five dicamba-based ionic liquids (HILs) were prepared through metathesis reaction. • HILs were self-assembled into nanoparticles (HIL NPs) via noncovalent interactions. • The obtained HIL NPs had desirable physicochemical properties. • The HIL NPs had an improved herbicidal activity. • The HIL NPs could reduce the off-target loss and risks to the environment. [ABSTRACT FROM AUTHOR]

The widespread adoption of genetically modified (GM) dicamba-tolerant (DT) soybean was followed by numerous reports of off-target dicamba damage and yield losses across most soybean-producing states. In this study, a subset of the USDA Soybean Germplasm Collection consisting of 382 genetically diverse soybean accessions originating from 15 countries was used to identify genomic regions associated with soybean response to off-target dicamba exposure. Accessions were genotyped with the SoySNP50K BeadChip and visually screened for damage in environments with prolonged exposure to off-target dicamba. Two models were implemented to detect significant marker-trait associations: the Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway (BLINK) and a model that allows the inclusion of population structure in interaction with the environment (G×E) to account for variable patterns of genotype responses in different environments. Most accessions (84%) showed a moderate response, either moderately tolerant or moderately susceptible, with approximately 8% showing tolerance and susceptibility. No differences in off-target dicamba damage were observed across maturity groups and centers of origin. Both models identified significant associations in regions of chromosomes 10 and 19. The BLINK model identified additional significant marker-trait associations on chromosomes 11, 14, and 18, while the G×E model identified another significant marker-trait association on chromosome 15. The significant SNPs identified by both models are located within candidate genes possessing annotated functions involving different phases of herbicide detoxification in plants. These results entertain the possibility of developing non-GM soybean cultivars with improved tolerance to off-target dicamba exposure and potentially other synthetic auxin herbicides. Identification of genetic sources of tolerance and genomic regions conferring higher tolerance to off-target dicamba may sustain and improve the production of other non-DT herbicide soybean production systems, including the growing niche markets of organic and conventional soybean.

Dicamba is a post-emergence herbicide commonly used to control broadleaves in cereal crops. However, a portion of the herbicide might reach soil surface, and many factors could affect its dynamics and effects. The objective of this research was to evaluate the dynamics of dicamba applied to the soil, to the soil and covered with straw and over the straw, in addition, to evaluate the weed control in pre-emergence. Two field experiments at different locations were conducted with dicamba. To quantify dicamba in the soil a LC-MS/MS system was used. In both experiments, rainfall and straw played a key role in dicamba soil dynamics and weed control. Dicamba in the soil was affected by presence of straw and accumulated rainfall after the application. Higher concentrations (254–432 ng g soil−1) in the soil 0–10 cm layers and greater leaching potential were found for the application in the soil compared to over the straw. The maximum concentration of dicamba (101.6–226 ng g soil−1) was found after 10 mm of rainfall for dicamba application over the straw. Around 60–70% of weeds were controlled with concentrations greater than 20 ng/g soil−1, in the presence or absence of straw. [ABSTRACT FROM AUTHOR]

The effect of the parameters of the suspension process for the production of EPDM synthetic ethylene-propylene rubbers, which leads to the production of rubbers with yields of more than 10 kg of rubber per 1 g of vanadium with physicochemical properties that correspond to the most popular grades of EPDM rubbers, was investigated. Ethylene, propylene, and ethylidenenorbornene or dicyclopentadiene were used as monomers. It was shown that realization of the suspension process in the presence of the catalytic system vanadium {2,4-ditertbutyl-6-[(tert-butylimino)methyl]phenolate}oxodichloride–ethyl trichloroacetate–diethylaluminum chloride leads to the production of EPDM rubbers with yields of 10000–23000 g/g of vanadium. The obtained grades of EPDM rubbers can be used in the automotive and construction industries, in the production of rubber products, sealants, adhesives, and as additives for technological fluids. [ABSTRACT FROM AUTHOR]

Natural populations evolve in response to biotic and abiotic changes in their environment, which shape species interactions and ecosystem dynamics. Agricultural systems can introduce novel conditions via herbicide exposure to non‐crop habitats in surrounding fields. While herbicide drift is known to produce a variety of toxic effects in plants, little is known about its impact on nontarget wildlife species interactions. In a two‐year study, we investigated the impact of herbicide drift on plant–herbivore interactions with common weed velvetleaf (Abutlion theophrasti) as the focal species. The findings reveal a significant increase in the phloem‐feeding silverleaf whitefly (Bermisia tabaci) abundance on plants exposed to herbicide at drift rates of 0.5% and 1% of the field dose. We also identified a significant phenotypic trade‐off between whitefly resistance and herbicide resistance in addition to whitefly resistance and relative growth rate in the presence of dicamba drift after increasing the populations grown in Year 2. In a follow‐up greenhouse study, we found evidence that dicamba drift at 0.5% of the field dose significantly increased the average chlorophyll content (in milligrams per square centimeter) along with a positive correlation between whitefly abundance and chlorophyll content. Overall, these findings suggest herbicide exposure to nontarget communities can significantly alter herbivore populations, potentially impacting biodiversity and community dynamics of weed populations found at the agro‐ecological interface. [ABSTRACT FROM AUTHOR]

BACKGROUND: Chenopodium album L. is a troublesome weed in spring‐planted crops, and different levels of ploidy have been documented for this weed species. A population of C. album has evolved resistance to dicamba. The level of ploidy and inheritance of dicamba resistance was studied in this population. RESULTS: The resistant and susceptible individuals of C. album were confirmed as tetraploid by flow cytometry. Pair‐crosses were made between ten resistant and susceptible individuals. Eight F1 individuals from five crosses were confirmed resistant after treating with dicamba at 400 g a.e. ha−1. These individuals were selfed, and the response of their progenies to dicamba was assessed in dose–response experiments, and the results confirmed the resistance trait was dominant. Furthermore, an analysis of the segregation patterns revealed that the segregation response of all F2 progenies fitted a 3:1 (resistant/susceptible) ratio when treated with dicamba at 200, 400 and 800 g a.e. ha−1, suggesting a single gene was responsible for dicamba resistance. CONCLUSIONS: Dicamba resistance in the studied tetraploid population of C. album is governed by a single dominant gene. This type of inheritance suggests that selection for dicamba resistance can occur readily. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Widespread pesticide drift issues ensued from the advent of dicamba-tolerant crop systems in the late 2010s, resulting in millions of acres of damaged farmland. Farmers who suffered drift-related losses in crop yield had to seek recovery in state courts. However, state courts varied in their approaches to drift lawsuits and remedies, if awarded, could include damage awards or injunctions. To demonstrate the need for a more transparent judicial process, this paper identifies three torts commonly advanced as causes of actions in drift cases and creates theoretic-game models to evaluate each tort's impact on farmers' decision-making and economic outcomes. [ABSTRACT FROM AUTHOR]

2,4-D and dicamba are used in the postemergence management of eudicotyledonous weeds in different crops, most of which are grown under no-tillage systems. Due to the application methods for these products, their dynamics in straw and their residual action in soil have rarely been explored. Thus, the objective of this study was to evaluate the dynamics of 2,4-D and dicamba that have been applied to corn straw and to verify their relationship with residual control action in weeds. In the dynamics experiments, the herbicides were applied to 5 t ha−1 of straw, and rainfall simulations were performed with variable amounts and at different periods after application to evaluate herbicide movement in the straw. In the residual action experiments, the species Digitaria insularis, Conyza spp., Bidens pilosa, Amaranthus hybridus, Euphorbia heterophylla, and Eleusine indica were sown in trays, and 2,4-D and dicamba were applied directly to the soil, to the soil with the subsequent addition of the straw, and to the straw; all of these applications were followed by a simulation of 10 mm of rain. The physical effect of the straw and the efficacy of the herbicides in terms of pre-emergence control of the weed species were evaluated. The leaching of 2,4-D and dicamba from the corn straw increased with a higher volume of rainfall, and the longer the drought period was, the lower the final amount of herbicide that leached. The presence of the corn straw on the soil exerted a physical control effect on Conyza spp.; significantly reduced the infestation of D. insularis, B. pilosa, A. hybridus, and E. indica; and broadened the control spectrum of 2,4-D and dicamba, assisting in its residual action and ensuring high levels of control of the evaluated weeds. In the absence of the straw, 2,4-D effectively controlled the pre-emergence of D. insularis, Conyza spp., and A. hybridus, and dicamba effectively controlled D. insularis, Conyza spp., B. pilosa, A. hybridus, E. heterophylla, and E. indica. [ABSTRACT FROM AUTHOR]

In 2019, worldwide cultivation of herbicide-resistant crops covered 166.6 million hectares and 88% of the global genetically modified (GM) crop area. Since the introduction of soybeans that are resistant to the herbicide glyphosate, a 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase inhibitors, many farmers have repeatedly used the glyphosate herbicide in crops such as corn, cotton, and rice, and weeds have now been found to resist it. The appearance of weeds, resistant to EPSP synthase (EPSPS) inhibitors, acetolactate synthase (ALS), synthetic auxins, and photosystem II(PSII) inhibitors, have caused farming difficulties. Therefore, we have taken a genetic approach to herbicide resistance as a developing method in these GM crops. Patients from five major countries, including the United States of America (US), China (CN), Europe (EP), Japan (JP), and Korea (KR), with the World Intellectual Property Organization (WIPO) are being searched, the trend on the herbicide resistance transgenes including EPSPS, glyphosate oxidase (GOX), glyphosate-N-acetyltransferase (GAT), glyphosate decarboxylase, phosphinothricin acetyltransferase (PAT), dicamba monooxygenase (DMO), aryloxyalkanoate dioxygenase (AAD), 2,4-D monooxygenase, acetolactate synthase (ALS), acetohydroxyacid synthase (AHAS), photosystem II protein D1, cytochrome P450, hydroxyphenylpyruvate dioxygenase (HPPD), bromoxynil nitrylase (BXN) and applied crops including soybean, canola, cotton, corn, wheat, carnation, rice, tobacco, tomato are analyzed separately. Multinational conglomerates such as Monsanto, Dow, BASF and Bayer are concentrating and maintaining their influence on the development of soybean and corn using genes such as EPSPS, AHAS and HPPD. Therefore, in the case of other developers, it would be better to develop other crops to which other genes such as P450, BOX, and D1 are applied. [ABSTRACT FROM AUTHOR]

Sosnowsky's hogweed (Heracleum sosnowskyi Manden.) is known as an invasive, ineligible, harmful to human health, and hardly controlled plant. The purpose of this study was to evaluate the efficiency of chemical control when different herbicides were applied at various development stages of H. sosnowskyi plants. The experiment was carried out in Ukraine over the period of 2013-2020. Two field experiments on the first-year and second-year H. sosnowskyi plants were conducted. All the selected herbicides were applied at the rates registered in Ukraine. The first-year plants of H. sosnowskyi were the most sensitive to the herbicides at the cotyledon stage - the efficacy of herbicides ranged from 97.3% to 100%. Postponing the herbicide application up to a six-leaf stage, the efficacy ranged from 43.2% to 60.7%. The most effective were the following herbicides: Task Extra 66.5 WG (rimsulfuron 23 g kg-1, nicosulfuron 92 g kg-1, dicamba 550 g kg-1) + Trend 90 at application rates of 385 g ha-1 + 0.2 L ha-1 and MaisTer Power OD (foramsulfuron 31.5 g L-1 + iodosulfuron 1.0 g L-1 + thiencarbazone-methyl 10 g L-1 + cyprosulfamide (antidote) 15 g L-1) at an application rate of 1.5 L ha-1. The second-year plants of H. sosnowskyi were effectively controlled by the following herbicides: Elumis 105 OD (mesotrione 75 g L-1, nicosulfuron 30 g L-1) at an application rate of 2.0 L ha-1 and the tank composition Elumis 105 OD + Roundup Max (glyphosate potassium salt 551 g L-1) at application rates of 2.0 + 6.0 L ha-1. The results of the experiment clearly showed that the sensitivity of H. sosnowskyi plants to herbicides decreased with increasing the stages of plant development of the first-year of H. sosnowskyi. The results suggest that the combination of mesotrione, nicosulfuron, and glyphosate might be a suitable solution for the chemical control of second-year plants of Sosnowsky's hogweed. [ABSTRACT FROM AUTHOR]

The increasing use of pesticides in modern agriculture has led to increased concerns about the risk of pollution of surface waters, soil and its agro-productive properties. The application of large doses of pesticides using outdated technologies and non-performing agricultural equipments, with poor application in terms of distribution uniformity and the lack of farmers’ knowledge and measures to prevent the drift phenomenon leads to their spread outside the targeted areas and implicitly to the increase of environmental pollution. In the present study, three anti-drift agents: EM260 (dodecilbenzensulfonat of calcium 50%, and butanol 18%), SC (heptametiltrisiloxan polietilenglicol) and respectively SO (surfactant non – ionic) have been tested according to ISO 22866, in the field conditions of Agricultural Research Development Station (ARDS) Caracal, Romania. The obtained results emphasized that the most valuable, among all variants, was EM260 (dodecilbenzensulfonat of calcium 50%, and butanol 18%) with smaller drift effect recorded at 1 meter distance (6.4%), followed by the second point, at 3 meters (3.1%) and at 5 meters with a calculated value of 2.1%. Also, at this variant the affected plants percent was smallest from the entire tested assortment, of 35.2%. [ABSTRACT FROM AUTHOR]

Significant losses in agricultural production are due to abiotic stresses, such as herbicide phytotoxicity. Dicamba (diglycolamine salt) is a herbicide used for post-emergent control of broadleaf weeds. It has a possibility to vapor-spread into neighboring fields causing damage to other crops. However, not every stress can be easily identified. Therefore, remote sensing has the potential as a new tool in early injury detection. This study evaluated the effects of simulated dicamba drift on the occurrence of phytotoxicity in soybeans (Glycine max). Soybean was assessed in seven dicamba doses (0, 0.056, 0.56, 5.6, 11.2, 28, 112 g ha−1) for changes in plant injury (scale of notes), spectral aspects (triangular greenness index (TGI), and shoot dry mass. The plants were photographed using a digital camera positioned at 1.2 m above the planting media level. The results indicate a positive effect of low dicamba doses (0.56 and 0.056 g a.e. ha−1) on TGI canopy distinction and shoot dry mass. Soybean TGI canopy distinction and the injury scale estimated at 45 days after sowing, and the soybean shoot dry mass observed at 99 days after sowing, presented significant and moderate Pearson's r coefficient of correlations (r = −0.609 and 0.625), indicating TGI as a valid and practical spectral index for plant dicamba-injured evaluations. [ABSTRACT FROM AUTHOR]

Glyphosate is a globally applied herbicide yet it has been relatively undetectable in-field samples outside of gold-standard techniques. Its presumed nontoxicity toward humans has been contested by the International Agency for Research on Cancer, while it has been detected in farmers' urine, surface waters and crop residues. Rapid, on-site detection of glyphosate is hindered by lack of field-deployable and easy-to-use sensors that circumvent sample transportation to limited laboratories that possess the equipment needed for detection. Herein, the flavoenzyme, glycine oxidase, immobilized on platinumdecorated laser-induced graphene (LIG) is used for selective detection of glyphosate as it is a substrate for GlyOx. The LIG platform provides a scaffold for enzyme attachment while maintaining the electronic and surface properties of graphene. The sensor exhibits a linear range of 10-260 μm, detection limit of 3.03 μm, and sensitivity of 0.991 nA μm-1. The sensor shows minimal interference from the commonly used herbicides and insecticides: atrazine, 2,4-dichlorophenoxyacetic acid, dicamba, parathion-methyl, paraoxon-methyl, malathion, chlorpyrifos, thiamethoxam, clothianidin, and imidacloprid. Sensor function is further tested in complex river water and crop residue fluids, which validate this platform as a scalable, direct-write, and selective method of glyphosate detection for herbicide mapping and food analysis. [ABSTRACT FROM AUTHOR]

Tomato (Solanum lycopersicum L.) plants are commonly injured by the off-target movement of synthetic auxin herbicides. A greenhouse and a field trial were conducted to determine the relative tolerance of eight fresh market tomato cultivars to drift-simulating rates of dicamba or 2,4-D. Tomato cultivars included 'BHN 589', 'Celebrity', 'Florida 91', 'Mountain Merit', 'Primo Red', 'Red Deuce', 'Red Morning', and 'Skyway'. Dicamba (3,6-dichloro-methoxybenzoic acid) and 2,4-D (2,4-dichlorophenoxyacetic acid) were applied at 2.8 g ae ha−1 and 5.3 g ae ha−1-D, respectively. By 14 weeks after treatment (WAT), herbicide-treated plants of each cultivar produced less total and marketable yield than their respective nontreated control in the greenhouse trial. For most cultivars, dicamba-treated plants had less marketable yield than 2,4-D-treated plants in the greenhouse. Herbicide treatments also reduced total and marketable yields of each cultivar when compared with their control in the field study at 14 WAT, except for 'Mountain Merit'. The severity of yield loss from herbicide treatments was cultivar-dependent. Field-grown 'Skyway' plants treated with dicamba produced the lowest marketable yield. In contrast, herbicide-treated plants of 'Florida 91' produced high marketable yields in the field, but 'Red Deuce' plants receiving 2,4-D were also highly productive. Herbicide residue in fruit sampled the third week of the harvest was nondetectable. Because the type of auxin herbicide drift is often unanticipated, 'Florida 91' may be the preferred cultivar for cultivation among those tested to maximize tomato production in the field. [ABSTRACT FROM AUTHOR]

3,6-Dichlorosalicylic acid (3,6-DCSA) is the demethylation metabolite of herbicide 3,6-dichloro-2-methoxy benzoic acid (dicamba). Previous studies have shown that anaerobic sludge further transformed 3,6-DCSA through decarboxylation and dechlorination. However, the anaerobe, enzyme, and gene involved in the anaerobic degradation of 3,6-DCSA are still unknown. In this study, an anaerobic sludge that efficiently degraded dicamba was enriched, and a 3,6-DCSA decarboxylase, designated chlorosalicylic acid decarboxylase (CsaD), was partially purified and identified from the anaerobic sludge. Metagenomic analysis showed that the csaD gene was located in a gene cluster of metagenome-assembled genome 8 (MAG8). MAG8 belonged to an uncultured order, OPB41, in the class Coriobacteriia of the phylum Actinobacteria , and its abundance increased approximately once during the enrichment process. CsaD was a non-oxidative decarboxylase in the amidohydrolase 2 family catalyzing the decarboxylation of 3,6-DCSA and 6-chlorosalicylic acid (6-CSA). Its affinity and catalytic efficiency for 3,6-DCSA were significantly higher than those for 6-CSA. This study provides new insights into the anaerobic catabolism of herbicide dicamba.IMPORTANCEDicamba, an important hormone herbicide, easily migrates to anoxic habitats such as sediment, ground water, and deep soil. Thus, the anaerobic catabolism of dicamba is of importance. Anaerobic bacteria or sludge demethylated dicamba to 3,6-DCSA, and in a previous study, based on metabolite identification, it was proposed that 3,6-DCSA be further degraded via two pathways: decarboxylation to 2,5-dichlorophenol, then dechlorination to 3-chlorophenol (3-CP); or dechlorination to 6-CSA, then decarboxylation to 3-CP. However, there was no physiological and genetic validation for the pathway. In this study, CsaD catalyzed the decarboxylation of both 3,6-DCSA and 6-CSA, providing enzyme-level evidence for the anaerobic catabolism of 3,6-DCSA through the two pathways. CsaD was located in MAG8, which belonged to an uncultured anaerobic actinomycetes order, OPB41, indicating that anaerobic actinomycetes in OPB41 was involved in the decarboxylation of 3,6-DCSA. This study provides a basis for understanding the anaerobic catabolism of dicamba and the demethylation product, 3,6-DCSA., Competing Interests: The authors declare no conflict of interest.

Biobeds are presented as an alternative for good pesticide wastewater management on farms. This work proposes a new test for in-situ biomonitoring of pesticide detoxification in biobeds. It is based on the assessment of visually appreciable injuries to Eisenia fetida. The severity of the injury to each exposed individual is assessed from the morphological changes observed in comparison with the patterns established in seven categories and, an injury index is calculated. A linear relationship between the proposed injury index and the pesticide concentration was determined for each pesticide sprayed individually in the biomixture. The five pesticides used were atrazine, prometryn, clethodim, haloxyfop-P-methyl and dicamba. In addition, a multiple linear regression model (i.e., a multivariate response surface) was fitted, which showed a good generalization capacity. The sensitivity range of the injury test was tested from 0.01 to 630 mg kg -1 as the total pesticide concentration. This index is then used to monitor the detoxification of these pesticides in a biomixture (composed of wheat stubble, river waste, and soil, 50:25:25% by volume) over 210 days. The results are compared with standardized tests (Eisenia fetida avoidance test and Lactuca sativa seed germination test) carried out on the same biomixture. The results are also compared with data on the removal of pesticides. The injury test showed a better correlation with the removal of pesticides than the avoidance test and seed germination test. This simple and inexpensive test has proved to be useful for decontamination in-situ monitoring in biobeds., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:C. Zalazar reports financial support was provided by National Agency for the Promotion of Research Technological Development and Innovation. If there are other authors, they 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 Elsevier Ltd. All rights reserved.)

Off-target movement of dicamba has been blamed for damaging millions of hectares of soybean in the United States since registration of the herbicide for use in dicamba-resistant cotton and soybean. Understanding the effect of a low dose of dicamba on non-dicamba-resistant soybean across multiple cultivars, growth stages, and planting dates could help producers better understand the implication of current management practices on yield loss from dicamba in fields where non-dicamba-resistant soybean are grown. A field experiment was conducted in 2019 in Fayetteville and Stuttgart, Arkansas, to evaluate the impact of planting date on response of soybean to a low dose of dicamba. The hypothesis of the planting date experiment was that soybean injury and yield loss will differ depending on planting date and dicamba application timing. Additionally, an experiment was conducted in 2018 and 2019 in Fayetteville to assess whether cultivars differ in sensitivity to dicamba. The hypothesis of the cultivar experiment was that genetic differences of soybean cultivars will allow for differential tolerance to dicamba. In the cultivar experiment, "Eagle DrewSoy" was identified as having enhanced tolerance to dicamba based on reduced injury (47% at R1 and 26% at V3) over both experimental years and locations. Soybean height in this experiment was affected only by application timing. In the planting date experiment, planting after mid-June resulted in reduced yields from dicamba injury. Dicamba exposure reduced yield at the July planting date (61% reduction from nontreated) more severely when compared to dicamba-treated plots of other planting dates (94% average relative yield among other planting dates), indicating that the negative effects of dicamba are increasingly deleterious for soybean planted later in the growing season. Maximum injury manifestation was generally delayed at later planting dates, indicating that dicamba may have been metabolized more slowly. [ABSTRACT FROM AUTHOR]

With the release of the dicamba-resistant crop technology and subsequent increase in dicamba off-target movement to non-dicamba-resistant crops, discovering means of mitigating yield loss through studying dicamba injury to soybean and interactions with factors such as irrigation regime and fertilization would prove beneficial. Field experiments were conducted in 2019 in Fayetteville and Colt, Arkansas, to evaluate the effect of irrigation regime to non-dicamba-resistant soybean that was injured by dicamba at a low dose at multiple timings. Another experiment was conducted in Fayetteville in 2019 and 2020 evaluating the impact of nitrogen (N) and potassium (K) fertilization on soybean recovery following injury by dicamba at multiple reproductive stages. Visible injury in both experiments was affected by application timing. Soybean yield components were impacted by dicamba applications within the irrigation regime experiment, and yields were decreased by dicamba applications; however, soybean yield was higher from branches than from the mainstem in dicamba-treated compared to nontreated plants. In the fertilization experiment, soybean treated with a low dose of dicamba that received N fertilization tended to have reduced biomass compared to treatments receiving no fertilizer or K alone, with greatest biomass reduction tending to occur among treatments receiving both N and K. Total grain yield was not affected by either irrigation regime or fertilization. While an increase in yield due to neither irrigation nor fertilization was observed, these results may help improve understanding of the effect of low-dose dicamba on soybean and aid producers making management decisions. [ABSTRACT FROM AUTHOR]

Dicamba, an important hormone-type systemic herbicide, is widely used to control more than 200 kinds of broadleaf weeds in agriculture. Due to its broad-spectrum, high efficiency and effectively killing glyphosateresistant weeds, dicamba is considered as an excellent target herbicide for the engineering of herbicide-resistant crops. In this study, an efficient dicamba-degrading microbial consortium was enriched from soil collected from the outfall of a pesticide factory. The enriched consortium could almost completely degrade 500 mg/L of dicamba within 12 h of incubation. A novel tetrahydrofolate (THF)-dependent dicamba demethylase gene, named dmt06, was cloned from the total DNA of the enriched consortium. Dmt06 shared the highest identity (72.3%) with dicamba demethylase Dmt50 from Rhizorhabdus dicambivorans Ndbn-20. Dmt06 was expressed in Escherichia coli BL21 and purified to homogeneity using Co2+-charged nitrilotriacetic acid affinity chromatography. The purified Dmt06 catalyzed the transfer of methyl from dicamba to THF, generating the herbicidally inactive metabolite 3,6-dichlorosalicylate (3,6-DCSA) and 5-methyl-THF. The optimum pH and temperature for Dmt06 were detected to be 7.4 and 35°C, respectively. Under the optimal condition, the specific activity of Dmt06 reached 165 nmol/min/mg toward dicamba, which was much higher than that of Dmt and Dmt50. In conclusion, this study cloned a novel gene, dmt06, encoding an efficient THF-dependent dicamba demethylase, which was a good candidate for dicamba-resistant transgenic engineering. [ABSTRACT FROM AUTHOR]

BACKGROUND: Cotton with resistance to 2,4‐d choline, glufosinate and glyphosate allows over‐the‐top use of these herbicides for postemergence weed control. Nontransgenic cotton is highly responsive to low rates of 2,4‐d, causing concern among farmers when the herbicide is applied near the crop. Injury to nearby cotton following application of 2,4‐d choline is sometimes blamed on volatilization of the herbicide. RESULTS: A large‐scale experiment was conducted in 2018–2021 to better understand causes of damage to nearby sensitive cotton following an application of 2,4‐d choline plus glufosinate‐ammonium. The herbicides were applied to 0.4 ha in the center of a 4‐ha non‐Enlist cotton field. At 30 min after application, air samplers were established in the treated center and outside the treated area in cardinal directions. The 72‐h cumulative air concentration of 2,4‐d in the swath ranged from 3.3 to 7.1 ng m−3, and most volatile residues (5.0–25.5 ng m−3) were detected in samplers established in the downwind direction directly adjacent to the treated field. Cotton plants in three downwind transects that were covered for 30 min after application were not damaged by 2,4‐d, whereas noncovered plants along the downwind transects were injured. No cotton injury occurred outside the treated area, except in the downwind direction during application even though wind direction changed after application. CONCLUSION: 2,4‐d choline volatilizes, but findings show that the volatilization is not sufficient to damage cotton in the neighboring area following applications, pointing to the importance of applicators understanding wind direction/shift during the application along with proximity of sensitive crops in the downwind direction. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Since the commercialization and widespread adoption of dicamba‐tolerant (DT) soybean cultivars across the United States, numerous cases of off‐target damage to non‐DT soybean have been reported. Soybean is naturally highly sensitive to dicamba, a synthetic auxin herbicide. Previous studies have focused on understanding the impact of growth stage, dosage, frequency, and duration of dicamba exposure on the severity of symptomology and yield loss. To date, little research has investigated the effect of genetic components in the observed responses. Therefore, this study was conducted to estimate yield losses caused by prolonged off‐target dicamba exposure and to identify genotypes with varying responses to off‐target damage. A total of 553 soybean genotypes derived from 239 unique biparental populations were evaluated in nine environments over 3 yr. A yield penalty of 8.8% was observed for every increment in damage score on a 1–4 scale with losses as high as 40%. Although the interaction between damage and maturity group (MG) significantly affected yield, genotypes showing the most tolerance had similar yields independent of their MG. This indicated that natural tolerance to off‐target dicamba may be conferred by physiological mechanisms other than the length of the recovery window. Given the widespread adoption of DT systems and potential yield losses in non‐DT soybean genotypes, identification of non‐DT soybean genotypes with higher tolerance to off‐target dicamba may sustain and improve the production of other non‐DT herbicide soybean production systems, including the niche markets of organic and conventional soybean. Core Ideas: Diverse soybean genetic backgrounds confer variable responses to off‐target dicamba exposure.Yield losses reached as high as 40% depending on the genetic background and severity of damage.Natural tolerance is conferred by physiological mechanisms other than the length of the window of recovery.Spatial distribution analysis indicates homogeneity of off‐target dicamba exposure. [ABSTRACT FROM AUTHOR]

The antibiotic resistance (AR) is a threatening risk for human health at a global scale. The propagation, dissemination and evolution of AR have been well-studied these years. With development of AR, the antibiotic-resistance bacteria (ARB) and antibiotic-resistance genes (ARGs) have been detected in almost all environmental systems and matrices. Herein, we attempted to summarize how ARB/ARGs become persist when they enter water environments and further be involved in geochemical processes especially at the interface of natural mineral with light irradiation. During the processes, bacteria have different form of transformation and come into stressed or non-stressed states. Their existed forms will be varied including being inactivated, transient tolerance and persistence phenotypes, which make AR problem become stubborn and complicated. Besides, separation of ARB and ARGs further intensified complexity of AR problem after naked ARGs diffusing into water, which acted as reservoir of ARGs and set stage for their transfer between bacteria. Furthermore, acquisition of ARGs mediated plasmid could even bring some advantages or disadvantage to bacteria, making problem more complex and uncontrollable. To enable AR under control, it is critical to understand the mechanism how ARB/ARGs participate in environmental geochemical transformation and in what condition that AR persistence happen. Understanding ponderance of AR persistence is not only key to properly assess its risk, but also to seriously prevent the continued development of AR. [ABSTRACT FROM AUTHOR]

Increased prevalence of glyphosate‐resistant (GR) weeds within agronomic cropping systems has led to the readoption of pre‐emergence (PRE) herbicides and use of multiple herbicide‐resistant soybean [Glycine max (L.) Merr.] cultivars. Herbicide programs were evaluated in the recently commercialized dicamba/glyphosate/glufosinate‐resistant (DGGR) soybean for weed control, reduction of Palmer amaranth (Amaranthus palmeri S. Watson) seed production, crop safety, and economic performance. At 35 days after pre‐emergence herbicides, acetochlor plus dicamba plus metribuzin, acetochlor/fomesafen plus dicamba, dicamba plus flumioxazin, and imazethapyr/pyroxasulfone/saflufenacil provided 80–99% control of velvetleaf (Abutilon theophrasti Medik.), Palmer amaranth, common lambsquarters (Chenopodium album L.), and Poaceae species. Evaluation at 14 days after early postemergence herbicides indicated PRE followed by (fb) POST applications of mixtures of acetochlor, dicamba, glufosinate, and glyphosate provided 80–99% weed control compared with 67–93% control in POST‐only programs. Most herbicide programs provided 83–99% control of grass and broadleaf weeds, with 85–91% weed biomass reductions at 28 days after late‐POST. The PRE fb POST programs reduced Palmer amaranth seed production by 94–99%, whereas POST‐only programs provided 75–83% reduction. In 2020, most programs provided gross profit margins ≥US$1,000 ha−1, with glufosinate fb glufosinate and imazethapyr/pyroxasulfone/saflufenacil fb acetochlor plus glufosinate providing $1,481 and $1,466 ha−1, respectively. Benefit/cost ratios ranged between 0.3 and 3.9 in 2019 due to hail but increased to 2.9–10.9 in 2020. Results of this study support use of PRE herbicides with multiple sites of action in DGGR soybean and indicate that glufosinate can provide POST control of GR Palmer amaranth. Core Ideas: Weed control was improved in most PRE fb POST herbicide programs compared with POST‐only programs.Programs that included dicamba in POST applications had reduced Palmer amaranth seed production.Glufosinate provided effective control of glyphosate‐resistant Palmer amaranth. [ABSTRACT FROM AUTHOR]

Off‐target movement of glyphosate can be severely injurious to rice (Oryza sativa L.). Glyphosate is routinely mixed with dicamba and applied to crops with resistance to both herbicides, such as glyphosate‐ and dicamba‐resistant corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] cultivars. This research was conducted to evaluate the effects of low rates of glyphosate and glyphosate plus dicamba on rice at multiple application timings. Separate field experiments were conducted and were repeated in 2018 and 2019 near Stuttgart, AR. The first experiment evaluated rice's response to glyphosate alone; a second experiment evaluated responses to glyphosate applied as a mixture with dicamba over several rice growth stages. The rates of glyphosate alone evaluated were 0.023, 0.047, 0.187, and 0.375 oz acid equivalent (ae) acre–1. Mixtures of glyphosate plus dicamba were evaluated at 0.050 plus 0.025, 0.2 plus 0.1, and 0.8 plus 0.4 oz ae acre–1, respectively. Visible injury to rice from glyphosate alone was never more than 3%, averaged over application timings. Unique symptomology and greater yield losses were observed for glyphosate mixed with dicamba. There was no reduction in rough rice grain yield after treatment with glyphosate alone. For the glyphosate plus dicamba experiment, no more than 13% injury occurred from any treatment. Rough rice grain yield was reduced by 21% relative to the nontreated control for the highest rate of glyphosate plus dicamba, averaged over application timings. Care should be taken to prevent off‐target movement of mixtures of glyphosate plus dicamba to neighboring rice. Core Ideas: Glyphosate contamination at ≥0.375 oz acid equivalent acre–1 is unlikely to injure rice.Dicamba may cause unique symptomology in rice.Dicamba and glyphosate together may injure rice more than glyphosate alone. [ABSTRACT FROM AUTHOR]