Upland cotton is sensitive to 2,4-dichlorophenoxyacetic acid (2,4-D), and the identification of potentially 2,4-D tolerant cotton chromosome substitution (CS) lines and understanding tolerance mechanisms provide a significant step into the development and genetic improvement of upland cotton to reduce yield loss caused by 2,4-D herbicide effects including the drifts. Experiments were conducted to understand the possible mechanism of herbicide tolerance in CS-T04-15, CS-T07, and CS-B15sh, 2,4-D herbicide-tolerant cotton CS lines compared with TM-1, the 2,4-D herbicide susceptible recurrent parent of the CS line as control, using [14C]2,4-D. Percent absorption rate and translocation patterns of the 14C-labeled herbicide application at 5.17 kBq at 6 to 48 hours after treatment (HAT) were determined. The tolerant cotton CS lines showed 15-19% [14C]2,4-D uptake while TM-1 exhibited a reduced uptake of only 1.4% [14C]2,4-D at 24 HAT. Distribution of the absorbed [14C]2,4-D showed that 2-5% was translocated outside the treated leaf. In TM-1, 77% of the herbicide was translocated above and below the treated leaf, contrasting with the reduced translocation of 14C-labeled herbicide observed in the tolerant CS lines. Interestingly, CS-T04-15 showed a restricted movement of 14C below the treated leaf at 6 to 48 HAT, suggesting a novel mechanism of herbicide tolerance. This finding is the first report on upland cotton demonstrating a complex differential uptake and translocation associated with herbicide tolerance for [14C]2,4-D in cotton CS lines.

Water hyacinth (Eichhornia crassipes) is an invasive species that has modified ecosystem functioning in the Sacramento-San Joaquin Delta (Delta), California, USA. Studies in lakes and rivers have shown that water hyacinth alters water quality. In tidal systems, such as the Delta, water moves back and forth through the water hyacinth patch so water quality directly outside the patch in either direction is likely to be impacted. In this study, we asked whether the presence or treatment of water hyacinth with herbicides resulted in changes in water quality in this tidal system. We combined existing datasets that were originally collected for permit compliance and long-term regional monitoring into a dataset that we analyzed with a before-after control-impact (BACI) framework. This approach allowed us to describe effects of presence and treatment of water hyacinth, while accounting for seasonal patterns in water quality. We found that although effects of treatment were not detectable when compared with water immediately upstream, dissolved oxygen and turbidity became more similar to regional water quality averages after treatment. Temperature became less similar to the regional average after treatment, but the magnitude of the change was small. Taken together, these results suggest that tidal hydrology exports the effects of water hyacinth upstream, just as river flow is known to transport the effects downstream, creating a buffer of altered water chemistry around patches. It also suggests that although water hyacinth has an effect on dissolved oxygen and turbidity, these parameters recover to regional averages after treatment.

A greenhouse dose-response study was conducted to determine the tolerance of three wild tomato accessions (TOM199, TOM198, TOM300) in comparison to a commercial cultivar (Better Boy) against the dicamba application at five rates (0, 70, 140, 210, and 280 g ae ha-1) at 14 and 28 days after treatment (DAT). Several physiological traits were evaluated at 0, 1, 3, 5, and 7 DAT. Wild accessions and cultivar were killed at all rates above 70 g ae ha-1 at 14 and 28 DAT, which is why differences between accessions and cultivar were only evident at 70 g ae ha-1. The GR50 (the herbicide rate that causes 50% reduction in dry weight) of Better Boy was 4.4 g ae ha-1 at 28 DAT, and this cultivar was approximately 11-fold more sensitive than wild accessions. At 7 DAT, the levels of H2O2 for wild accessions were lower than Better Boy up to 5 at 70 g ae ha-1 of dicamba. Furthermore, wild accessions showed lower herbicide absorption than Better Boy at all dicamba doses at 1, 3, and 7 DAT. All the three wild accessions expressed tolerance to the dicamba application at the dose of 70 g ae ha-1. At the same time, Better Boy and wild accessions were susceptible to dicamba application at rates of 140, 210, and 280 g ae ha-1.

The Eucalyptus genus is the most planted forest crop in the world, with Brazil being one of the countries with the greatest productive potential. However, the occurrence of weeds can cause losses in productivity. Chemical control is widely used, but the efficiency of herbicides depends on factors such as the presence of straw in the soil and the occurrence of rainfall. Due to the scarcity of results regarding the interaction between herbicide, straw, and water depth in the forest sector, the objective of this study is to evaluate the efficiency of S-metolachlor + glyphosate in the control of grasses in different densities of eucalyptus straw and with simulated rain after the application of the product. The experiment was conducted in DBC, factorial 3×3×2, with four replications. The first factor represented 0, 50 and 100% of the commercial dose of S-metolachlor + glyphosate, the second 0, 5, and 10 ton ha-2 of straw, and the third 25 and 50mm of water depth applied in soil with a mix of grasses previously sowed. The rainfall simulation was performed 24 hours after herbicide application on each straw volume. The fresh mass of the aerial part of the grasses was collected 43 days after sowing and dried in an oven to determine the dry mass. Visual analyzes of the percentage of control were performed with scales ranging from 0 to 100, where 0 represents no control and 100 efficient control. The fresh and dry mass and the grasses' dry mass/water ratio decreased with increasing herbicide dosage and straw density. The dosage of 2.12 + 1.59 kg i.a. ha-1 of S-metolachlor + glyphosate resulted in greater control of grasses, and the treatments without straw and with the application of the herbicide had the highest percentages of control. Applying different water depths (25 mm or 50 mm) did not influence the control. Despite the control of grasses, the efficiency of the herbicide mixture was affected by the presence of vegetation cover.

Tribenuron-methyl is used extensively in Iranian cereal cropping systems under rainfed conditions. However, there is little information on the soil persistence and carryover of this herbicide and its phytotoxicity to subsequent crops in the rotation. This study was carried out with the aim of investigating the sensitivity of different chickpea cultivars to tribenuron-methyl and also finding alternative crops. In field experiments, the chickpea fields of Ravansar County, Kermanshah province, Iran were monitored during 2023-2022, and the growth of chickpea in response to residues of tribenuron-methyl used in the previous wheat crop was evaluated. Furthermore, in a greenhouse experiment, the effect of various concentrations of tribenuron-methyl on the growth of chickpeas, lentil and common vetch was investigated. In all the investigated species in this study, presence of tribenuron-methyl decreased plant growth. Ttotally, among examined crop species, lentil had a higher tolerance to tribenuron-methyl followed by common vetch and chickpea varieties. Bivanij chickpea variety was more sensitive to the residues of tribenuron-methyl in the soil (30% reduction in grain yield) when compared to the other two varieties, namely Mansour and Adel. Based on the results of this study, residues of tribenuron-methyl applied in wheat fields is the main responsible factor reducing the height of chickpea in rai-fed cropping systems of western Iran. It is recommended to replace lentil and common vetch with chickpeas in rotation with wheat in soils heavily contaminated with the residues of tribenuron-methyl.

Alopecurus myosuroides (blackgrass) is a problematic weed of Western European winter wheat and its success is largely due to widespread multiple-herbicide resistance. Previous analysis of F2 seed families derived from two distinct blackgrass populations exhibiting equivalent non-target site resistance (NTSR) phenotypes shows resistance is polygenic and evolves from standing genetic variation. Using a CIDER-seq pipeline we show that herbicide resistant (HR) and herbicide sensitive (HS) F3 plants from these F2 seed families as well as the parent populations they were derived from carry extra-chromosomal circular DNA (eccDNA). We identify the similarities and differences in the coding structures within and between resistant and sensitive populations. Although the numbers and size of detected eccDNAs varied between the populations, comparisons between HR and HS blackgrass populations identified shared and unique coding content, predicted genes, and functional protein domains. These include genes related to herbicide detoxification such as Cytochrome P450s, ATP-binding cassette transporters and glutathione transferases including AmGSTF1. eccDNA content was mapped to the Alopecurus myosuroides reference genome, revealing genomic regions at distal end of chromosome 5 and the near center of chromosome 1 and 7 as regions with high number of mapped eccDNA gene density. Mapping to 15 known herbicide-resistant QTL regions showed the eccDNA coding sequences match 12 with four QLT matching HS coding sequences one region only contained HR coding sequences. These findings establish that like other pernicious weeds, blackgrass has eccDNAs that contain homologs of chromosomal genes, and these may contribute genetic heterogeneity and evolutionary innovation to rapidly adapt to abiotic stresses including herbicide treatment.

The pre-emergent herbicide indaziflam is efficient in the management of weeds in eucalyptus crops, but this plant may develop less in soil contaminated with it. The objective was to evaluate the levels of chlorophylls a and b, the apparent electron transport rate (ETR), growth and dry matter of leaves, stems and roots of Clone I144, in clayey soil, contaminated with the herbicide indaziflam and the leaching potential of this herbicide. The design was completely randomized in a 3 x 5 factorial scheme, with four replications. Chlorophyll a and b contents, apparent electron transport rate (ETR), height growth and dry matter of leaves, stems and roots of Clone I144 were evaluated. The leaching of indaziflam in the clayey soil profile (69% clay) was evaluated in a bioassay with Sorghum bicolor, a plant with high sensitivity to this herbicide. The visual intoxication and height of this plant were evaluated at 28 days after sowing (DAS). Chlorophyll a and b contents and ETR, height and stem dry matter of Clone I144 were lower in soil contaminated with indaziflam residues. The dose of indaziflam, necessary to cause 50% (C50) of intoxication and the lowest height of sorghum plants, was 4.65 and 1.71 g ha-1 and 0.40 and 0.27 g ha-1 in clayey soil and sand, respectively. The sorption ratio (SR) of this herbicide was 10.65 in clayey soil. The herbicide indaziflam leached up to 30 cm depth at doses of 37.5 and 75 g ha-1 and its residue in the soil reduced the levels of chlorophylls a and b, the apparent electron transport rate (ETR) and the growth of Clone I144.

The intensive global use of glyphosate has led to the evolution of glyphosate resistant (GR) weed species, including the economically damaging horseweed (Conyza sumatrensis). We evaluated the glyphosate resistance mechanisms of C. sumatrensis. While 5-enolpyruvylshikimate-3-phosphate synthase activity was similar between the glyphosate resistant (GR) and nonresistant biotypes, plants from the GR population accumulated lower shikimate levels than susceptible ones, suggesting the absence of target-site resistance mechanisms. Decreases over time in glyphosate concentrations in GR leaves were not accompanied by increases in glyphosate concentrations in their stem and roots, indicating lower glyphosate distribution rates in GR plants. The early appearance of aminomethylphosphonic acid (the main glyphosate metabolite) in leaves, as well as its presence only in the stems and roots of GR plants, suggests faster glyphosate metabolism in GR plants than in susceptible ones. GR plants treated with glyphosate also showed greater antioxidant (ascorbate peroxidase [APX] and catalase [CAT]) and cytochrome P450-enzyme activities, indicating their great capacity to avoid glyphosate-induced oxidative stress. Three non-target mechanisms (reduced glyphosate translocation, increased metabolism, and increased antioxidant activity) therefore confer glyphosate resistance in C. sumatrensis plants. This is the first time that APX, CAT and P450 enzyme activities are related to GR in C. sumatrensis.

New [1,2]dithiolo[3,4-b]pyridine-5-carboxamides were synthesized through the reaction of dithiomalondianilide (N,N'-diphenyldithiomalondiamide) with 3-aryl-2-cyanoacrylamides or by a three-component reaction involving aromatic aldehydes, cyanoacetamide and dithiomalon- dianilide in the presence of morpholine. The structure of 6-amino-4-(2,4-dichlorophenyl)- 7-phenyl-3-(phenylimino)-4,7-dihydro-3H-[1,2]dithiolo[3,4-b]pyridine-5-carboxamide was con-firmed using X-ray crystallography. To understand the reaction mechanism in detail, density functional theory (DFT) calculations were performed with a Grimme B97-3c composite computa-tional scheme. The results revealed that the rate limiting step is a cyclization process leading to the closure of 1,4-dihydropyridine ring with an activation barrier of 28.8 kcal/mol. Some of dithiolo[3,4-b]pyridines exhibited moderate herbicide safening effects against 2,4-D . Additional-ly, ADMET parameters were calculated and molecular docking studies were performed to identify potential protein targets.

Chemical weed control using herbicide glyphosate to manage emerged weeds is an important production practice in Florida citrus. Despite the extensive use of glyphosate in citrus orchards, very limited information is available on its environmental fate and behavior in Florida soils that are predominantly sandy in nature. Hence, the study's objective was to understand the adsorption-desorption, dissipation dynamics, and vertical movement or leaching of glyphosate in sandy soils in citrus orchards. Laboratory, field, and greenhouse experiments were conducted at Southwest Florida Research and Education Center in Immokalee, Florida. The adsorption-desorption behavior of glyphosate in the soils from three major citrus production areas in Florida was studied utilizing a batch equilibrium method. The dissipation of glyphosate was tracked in the field following its application at the rate of 4.20 kg ae ha-1. Soil leaching columns in greenhouse conditions were used to study the vertical movement of glyphosate. The results suggest that glyphosate has a relatively lower range of adsorption or binding (Kads = 14.28 to 30.88) in the tested soil types. The field dissipation half-life (DT50) of glyphosate from surface soil was found to be 26 days. Glyphosate moved vertically or leached into the soil profile, up to 40 cm in the soil column, when analyzed 40 days after herbicide application. The primary degradation product of glyphosate, i.e., aminomethyl phosphonic acid (AMPA), was also detected up to the depth of 30 cm below the soil surface, indicating the presence of microbial metabolism of glyphosate in the soil.

Glyphosate-based herbicide products are the most widely used broad-spectrum herbicides in the world for post-emergent weed control. There are ever-increasing concerns that glyphosate, if not used judiciously, may cause adverse non-target impacts in agroecosystems. The purpose of this brief review is to present and discuss the state of knowledge with respect to its persistence in the environment, possible effects on crop health, and impacts on crop nutrition.

We investigated the potential of Mucuna pruriens and Canavalia ensiformis as phytoremediation candidates for Tebuthiuron (TBT)-contaminated soils. Crotalaria juncea was the bioindicator specie for tebuthiuron and Lactuca sativa used in ecotoxicological bioassays, both analyses aim to verify the herbicide presence in soil samples as TBT is persistent with environmental and health risks due to its tendency to bioaccumulate. We conducted a 140-day greenhouse experiment associated with bioaugmentation by microbial inoculants - solid or liquid. Both C. ensiformis (CE) and M. pruriens (MP) exhibited distinct growth patterns, with MP demonstrating a faster growth rate than CE, evident from its higher growth apex (α = 84.52) and specific growth rate (k = 0.113). While soil samples with microbial inoculants demonstrated significant biomass increase with tebuthiuron absence, the introduction this herbicide notably hindered phytomass production, particularly in MP + TBT treatments. Liquid inoculant notably contributed to biomass accumulation in MP, whereas microbial bioaugmentation did not substantially enhance phytomass in CE under tebuthiuron presence. Furthermore, C. juncea exhibited initially slow development in the reference treatment but displayed accelerated growth and greater height with liquid inoculant compared to solid inoculant. Despite the presence of tebuthiuron, C. juncea in soil with TBT alone reached a maximum height exceeding 100 cm. However, tebuthiuron significantly reduced biomass accumulation in C. juncea, indicating its high sensitivity to this herbicide. Liquid inoculant facilitated the highest dry biomass accumulation in C. juncea, yet the introduction of tebuthiuron led to a considerable reduction in biomass, underscoring the plant's susceptibility to it. While bioaugmentation showed potential in mitigating herbicide phytotoxicity, its efficacy varied among tested inoculants. In bioassays with L. sativa, bioaugmentation with liquid inoculant resulted in a higher final germination index (GI) compared to solid inoculant and the reference treatment. Conversely, soil samples containing only tebuthiuron demonstrated a higher final GI and growth velocity compared to the reference treatment, implying the natural attenuation of toxicity over time. Additionally, previous cultivation of Mucuna pruriens positively influenced the development of test-organism, resulting in a higher GI and growth rate compared to the reference treatment. These findings provide valuable insights for various stakeholders, including the scientific community, industries, and bioengineers. They offer a strong incentive to develop advanced bioremediation strategies to address persistent pesticide contamination, especially in intensive agroecosystems like sugarcane-producing fields. Implementing our biological solution holds the potential to usher in a cleaner and safer era in agriculture, thereby protecting both society and the environment.

Several copolymer hydrogels were prepared from free radical copolymerization of 2-hydroxyethyl methacrylate (HEMA) with itaconic acid (IA). A series of Poly(2-hydroxyethyl methacrylate-co-itaconic acid) hydrogel, poly(HEMA-co-IA) were prepared at different feed monomer ratio using ammonium persulfate (APS) initiators in water at 70°C. The phytodrug 2,4-dichlorophenoxy acetic acid (2,4-D) were grafted to Poly(HEMA-co-IA) by esterification reaction. In addition, swelling behavior (Wt%) was studied at different pH. The hydrolysis of Poly(HEMA-co-IA)-2,4-D showed that the release of the bioactive compounds in aqueous phase, using Liquid-phase polymer-based retention (LPR) ultrafiltration system is dependent on the hydrophilic character as well as on pH value. The acid-hydrolysis of the herbicide from the conjugates follows a first order kinetics, showing higher kinetic constants as the pH increases. The base-catalyzed hydrolysis reaction of the herbicide follows a zero order kinetic, where the basic medium acts as a catalyst accelerating the release rate of the herbicide, showing higher kinetic constants as the pH increases. The differences in the release rates found for the hydrogel-herbicide at different pH can be correlated with the difference in their swelling capacity, where the release rate generally increases with an increase in the swelling capacity from water solution at higher pH. The study of the release process revealed that all samples in distilled water at pH 10 are representative of agricultural systems, showed first-order swelling kinetics and an absorption capacity that conforms to the parameters for hydrogels for agricultural application, which supports their potential for these purposes.

Precision agriculture including camera-guided row detection and hydraulic steering are often used as an alternative because crop damage can be decreased and driving speed can be increased comparable to herbicide applications.The effects of different approaches as uncontrolled (UC), mechanical weed control (MWC), herbicide weed control (HWC) and mechanical + herbicide control (MWC+HWC) on weed density and yield of sugar beet were tested and evaluated in two trials (2021 and 2022) in South Transylvania at the tested intervals BBCH 19 and 31. Weed control efficacy (WCE) depends on the emergence of the weeds and a good timing of weed controls in all the trials and methods, though the highest yield of sugar beet roots was recorded in the treatment MWC+HWC, with an increase up to 12-15% (56.48 t ha-1) yield from HWC (50.22 t ha-1) and a yield increase of more than 35- 40% than MWC (42.34 t ha-1). Our trials show that is possible to increase yield and have less chemical applications with the introduction of the new precision technologies in agriculture included here the sensor-guided mechanical controls.

Abstract: Using adjuvants to optimize and increase the efficacy of herbicides is an acceptable manner to reduce herbicides undesirable impact on the environment in sustainable agriculture. In this study, it was demonstrated that the application of 0.1% of the non-ionic surfactant (NIS, Contact) and 0.5 L ha-1 of a crop oil concentrate (COC, Renol) did not improve the efficacy of rimsulfuron on Amaranthus retroflexus. In contrast, the same treatments enhanced performance and rainfastnes of rimsulfuron in Chenopodium album in pot expriments. Increasing non-ionic surfactant concentration to 1 L ha-1 increased rimsulfuron performance around 11-fold for Amaranthus retroflexus compared to around 3-fold for Chenopodium album. The same treatment, also reduced the rainfastness of rimsulfuron on Amaranthus retroflexus while improving the rainfastness of rimsulfuron on Chenopodium album. Measured ED50 and ED90 values of rimsulfuron indicated that the addition of the 0.2 L ha-1 of NIS improved the recommended (60 g ai. ha-1) and the reduced (30 g ai. ha-1) of rimsulfurom in field. The highest potato yield measured (60 tons per ha) when 60 g ai. ha-1 rimsulfuron was applied at three stages (S1, S4, and S7) without using a NIS; not significant differences were measured when the same dose of rimsulfuron was applied at the three (S1, S4, and S7) and two (S1, S4) stages with NIS.

Some herbicides exert hormetic or biphasic non-monotonic dose-response (NMDR), which is one of the major challenges for ecological risk assessment (ERA) of pesticides pollution. In this study, fish embryo toxicity test (FET) with Javanese medaka (Oryzias javanicus) to sublethal concentration of diuron was determined. Inverted U-shape heart rate was observed at 3 days post-exposure (dpe) and 7 dpe. However, at 13 dpe the heart rate (104 ± 2.90 heartbeat/min.) decreased in 10.00 mg.L-1 exposed-embryos. At 20 dpe, hatchability and survival rate were reduced in 5.00 mg.L-1 and 10.00 mg.L-1 exposed groups. Hormetic developmental deformities were observed in embryo-larvae of Javanese medaka. The results revealed a biphasic effect of low concentrations of diuron on some morphological and physiological features of Javanese medaka embryo-larvae, which might be attributed to endocrine disruption of this herbicide. Further studies to support these effects were recommended.

Triclopyr is an auxin-like herbicide extensively employed to manage weeds in food crops and pastures. Triclopyr has been detected in environmental matrices, with a notable presence within aquatic ecosystems. Given the limited understanding of its fate in the environment, potential implications for environmental and human health, and the lack of adequate monitoring in various environmental compartments, triclopyr is now considered a contaminant of emerging concern (CEC). The present study was undertaken to investigate the impact of triclopyr on zebrafish development, with a specific focus on assessing its embryotoxic, behavioral, and neurotoxic effects at environmentally realistic concentrations ranging from 0.5 to 50 µM on zebrafish embryos. Our results revealed that triclopyr caused sublethal effects on zebrafish embryos, such as delayed hatchability at 50 µM, yolk sac retention at 0.5, 1, 5, and 10 µM, and uninflated swim bladder at 50 µM concentration of triclopyr. Moreover, a subtle alteration in the swimming activity of larvae was observed in the 10 µM triclopyr after 144 hours of exposure. However, the activity of acetylcholinesterase, remained unchanged after triclopyr exposure. Taken together, these comprehensive findings suggest that triclopyr can induce adverse effects on the early development of zebrafish, even at concentrations detected in aquatic environments.

Manual evaluation of crop injury to herbicides is time-consuming. Unmanned aircraft systems (UAS) and high-resolution multispectral sensors and machine learning classification techniques have the potential to save time and improve precision in the evaluation of herbicide injury in crops, including grain sorghum (Sorghum bicolor L. Moench). The objectives of this research were to (1) evaluate three supervised classification algorithms (support vector machine, maximum likelihood, and random forest) for categorizing high-resolution UAS imagery to aid in data extraction and (2) evaluate the use of vegetative indices (VIs) collected from UAV imagery as an alternative to traditional methods of visual herbicide injury assessment in mesotrione-tolerant grain sorghum breeding trials. An experiment was conducted in a randomized complete block design using a factorial treatment arrangement of three genotypes by four mesotrione doses. Herbicide injury was rated visually on a scale of 0 (no injury) to 100 (complete plant mortality). The UAS flights were flown at 9, 15, 21, 27, and 35 days after treatment. Results show the SVM algorithm to be the most consistently accurate, and high correlations (r = -0.83 to -0.94; p < 0.0001) were observed between the normalized difference vegetative index (NDVI) and ground-measured herbicide injury. Therefore we conclude that VIs collected with UAS coupled with machine learning image classification, has the potential to be an effective method of evaluating mesotrione injury in grain sorghum.

Despite the productivity, achieving long-term sustainability and maintaining plant biodiversity become the pivotal goals in orchard floor management, especially along tree rows. Thus, the paradigm of eradicating weeds in the tree row using chemical herbicide or repeated soil tillage needs to be substituted with more sustainable alternatives. This study was conducted in two commercial apple and peach orchards in Marche region (Italy). Two integrated mechanical approaches, integrated mowing (mower + brush or disc) and integrated tillage (blade weeder + integrated mowing), were compared with standard herbicide system in a 2-years trial. Weed species abundance, soil coverage rate, and weed biomass productions, including gas exchange parameters, tree growth, fruit yield and quality were measured. Both integrated practices had significant effects on the number of weed species, total vegetation coverage, and dry weed biomass production. No significant differences were found in terms of tree gas exchange parameters, growth and fruit yield. However, a few fruit quality parameters such as fruit firmness, solid soluble content and dry matter content responded positively to the integrated practices. These results suggest that the integrated mechanical approaches of weed management increased orchard biodiversity, and they had no adverse effects on tree growth, fruit yield, and quality.

Weeds are among the major constraints to any crop production system, reducing productivity and profitability. Herbicides are among the most effective methods to control weeds, and reliance on herbicides for weed control has increased significantly with the advent of herbicide-resistant crops. Unfortunately, over-reliance on herbicides leads to environmental-health issues and herbicide-resistant weeds, causing human-health and ecological concerns. Crop diversification can help manage weeds sustainably in major crop production systems. It acts as an organizing principle under which technological innovations and ecological insights can be combined to manage weeds sustainably. Diversified cropping can be defined as the conscious inclusion of functional biodiversity at temporal and/or spatial levels to improve the productivity and stability of ecosystem services. Crop diversification helps to reduce weed density by negatively impacting weed seed germination and weed growth. Additionally, diversified farming systems are more resilient to climate change than monoculture systems and provide better crop yield. However, there are a few challenges to adopting a diversified cropping system, which ranges from technology innovations, government policies, farm-level decisions, climate change, and market conditions. In this review, we discuss how crop diversification supports sustainable weed management, the challenges associated with it, and the future of weed management with respect to the diversification concept.

The ecotoxic effect of glyphosate, a commonly used Parthenium control herbicide, was evaluated in laboratory on biological and fitness attributes of Zygogramma bicolorata. Bioassay of glyphosate was carried within a minimum range of field recommended dose. Indirect exposure experiment reveals that glyphosate caused maximum mortality of 3^rd larval instars, extends the development stages of larvae, pre pupation and pupation. Significant negative effect was observed on sex ratio, fecundity, egg viability and on other fitness attributes. The study demonstrated the non-compatibility of glyphosate and unsafe with Zygogramma bicolorata. The study concludes that owing to acute toxicity of glyphosate at recommended field dose may be used in combination with Z. bicolorata for successful control of Parthenium weed, but needs to be evaluated under natural field conditions.

Glufosinate, a glutamine synthetase (GS) inhibitor, often provides variable weed control depending on environmental conditions such as light, temperature and humidity at the time of application. Midday applications normally provide improved efficacy compared to applications at dawn or dusk. We investigated the physiological, molecular, and biochemical basis for the time-of-day effect on glufosinate efficacy in Amaranthus palmeri. GS1 and GS2 gene expression and protein abundance were assessed in different parts (young leaves, old leaves, and roots) of plants incubated in the dark compared to those in the light. The turnover of GS total activity was also evaluated overtime following glufosinate treatment at midday compared to dusk application. The results suggest that GS in A. palmeri is less expressed and less abundant in the dark compared to in the light. Midday application of glufosinate under intense light conditions in the hours following application provide full control of A. palmeri plants. Consequently, these plants are unable to recover GS activity by de novo protein synthesis. Full activity of GS is required for complete inhibition by the irreversible inhibitor glufosinate. Therefore, glufosinate applications should always be performed in the middle of the day when sunlight is intense, to prevent weed escapes from the herbicide treatment.

Spectral image analysis has the potential to replace traditional approaches for assessing plant responses to different types of stress including herbicide, through non-destructive and high-throughput screening (HTS). Therefore, this study was conducted to develop a rapid bioassay method using a multi-well plate and spectral image analysis for diagnosis of herbicide activity and mode of action. Crabgrass (Digitaria ciliaris) as a model weed was cultivated in multi-well plates and subsequently treated with 6 herbicides with different modes of action when they reached the 1-leaf stage, using only a quarter of the recommended dose. To detect plant response to herbicides, plant spectral images were acquired after herbicide treatment using RGB, infrared (IR) thermal, and chlorophyll fluorescence (CF) sensors and analyzed for diagnosing herbicide efficacy and mode of action. Principal Component Analysis (PCA) using all spectral data successfully distinguished herbicides and clustered depending on their modes of action. The performed experiments have shown that the multi-well plate assay combined with spectral image analysis can be successfully applied for herbicide bioassay. In addition, the use of spectral image sensors, especially in CF image, would facilitate HTS by enabling rapid observation of herbicide response, as early as 3 hours after herbicide treatment.

Soybean are vulnerable to drought and temperature increases potentially induced by climate change. The purpose of this study was to determine if the use of cover crops (CC) can influence the gas exchange potential of glyphosate tolerant soybean when the vapor pressure deficit (Vpd) increases. This two years study was conducted in an open experimental field comprising Direct Seeding plots without CC (DS) or with CC (DSCC). Stomatal conductance (Gs) was measured five times on the same identified leaves following GBH application. These leaves were then collected in order to observe the stomata (size, density and stomatal index) with a scanning electron microscope and to perform measurements on foliar traits (venation density, width of midrib). The Vpd was calculated concomitantly to Gs measurements at the leaf surface. The results suggest that the use of CC promotes phenotypic change in soybean leaves (more elaborate venation and a higher stomatal density), which in turn may enhance their tolerance to drier conditions. In 2019, Gs could be up to 29% higher in DSCC plots compared to DS ones along with similar Vpd values. This study shows that the benefits of using CC can be observed through the morphological development strategies of the crop plants and their higher tolerance to drought.

Many natural areas are colonised by the invasive species Ailanthus altissima. Its presence in natural ecosystems damages the ecological richness while competing with native flora. A. altissima is one of the most widespread weed species in natural areas of temperate regions such as conservation parks, archaeological sites and communication corridors. Not many active ingredients are available to control this weed, being the most popular, the glyphosate, banned by many municipalities. In order to test the efficacy of alternative active ingredients, naturally occurring populations in Collserola Conservation Park of Barcelona (Catalonia, Spain) were treated with different herbicides using three different techniques. Aclonifen, metribuzin, flazasulfuron, metsulfuron-methyl, fluroxypyr, isoxaflutole + thiencarbazone-methyl and triclopyr mixed with 2.4-D, fluroxypyr, aminopyralid and clopyralid, were applied by stem injection, cut stump injection or basal bark techniques against trees of around 5 cm diameter. Both cut stump and stem injection gave almost total control of the trees while basal bark showed more varied results depending on the herbicide. Best control was achieved when flazasulfuron or triclopyr were present as active ingredients and poorer control was observed when using metsulfuron-methyl or isoxaflutole + thiencarbazone-methyl. Aclonifen showed no damage to the trees. Metribuzin worked better if the cut stump injection technique was used. These results showed that several alternatives are available to the use of glyphosate which is been banned for some uses due to environmental concerns.