Amount Of Herbicide Research Articles

Characterisation of low-level pyrasulfotole resistance and the role of herbicide translocation in wild radish (Raphanus raphanistrum)

The synthetic auxin 2,4-D and the 4-hydroxyphenylpyruvate dioxygenase inhibitor pyrasulfotole are phloem-mobile post-emergence herbicides, the latter applied in co-formulation with either bromoxynil (a contact herbicide causing leaf desiccation) or MCPA (another synthetic auxin). Previous studies have shown a wide range of 2,4-D translocation phenotypes in resistant populations of the agricultural weed Raphanus raphanistrum, but it was hypothesised that enhanced movement out of the apical meristem could contribute to resistance. Little is known about pyrasulfotole translocation or the effect of bromoxynil on pyrasulfotole movement. Therefore, the behaviour of pyrasulfotole and 2,4-D applied to the growing point of susceptible and resistant R. raphanistrum seedlings was assessed, along with the effect of bromoxynil on pyrasulfotole translocation. The small amount of herbicide directly contacting the growing point after spraying was sufficient to induce herbicide symptoms, and there was no enhancement of translocation away from the growing point in either pyrasulfotole- or 2,4-D-resistant populations. Bromoxynil had a slightly inhibitory effect on pyrasulfotole translocation in some populations, somewhat negating the minor differences observed among populations when pyrasulfotole was applied alone. Resistance to pyrasulfotole could not explained by enhanced metabolism or vacuolar sequestration of the herbicide. Overall, differential translocation in either the treated leaves or apical meristems does not appear to be a major determinant of resistance to pyrasulfotole or 2,4-D.

A Review on Nano Herbicides: The Future of Weed Management

Weeds pose significant challenges to global agricultural productivity, with India alone experiencing annual losses of $11 billion due to weed infestations, despite the extensive use of herbicides. The drawbacks of conventional herbicide formulations contribute to their suboptimal performance. Rotating herbicides and use of appropriate mixtures are two key approaches to suppress the weed floral shift and resistance development to herbicide in weeds. Doubts persist regarding the effectiveness of these herbicides, prompting the exploration of more efficient control methods. Using lower amounts of herbicides is preferred because it decreases the lasting impact of herbicide residues in agricultural regions and their environmental toxicity. Nano herbicides can facilitate the efficient transport of herbicides to weed plants, thereby minimizing the buildup of residues in the soil. Nanotechnology emerges as a promising avenue for herbicide development, offering 'Smart herbicides' with heightened effectiveness and reduced application volumes. Nano herbicides employ innovative mechanisms, effectively depleting weed seed banks, degrading germination inhibitors, and facilitating gradual herbicide release. Techniques like damaging weed pollen grains and utilising carbon nanotubes demonstrate inventive approaches to seed bank depletion. Controlled release formulations ensure prolonged and efficient weed suppression while minimising environmental impact. Moreover, incorporating metal ions accelerates herbicide residue degradation, mitigating environmental persistence. Enhanced plant growth with nano herbicide application emphasizes their potential as sustainable weed control solutions. However, further research is essential to ensure their safety and efficacy before widespread adoption in commercial agriculture, addressing potential risks associated with their application. Introducing nano herbicides signifies a significant advancement in sustainable weed management practices, promising a future where agricultural productivity can be safeguarded against weed infestations.

Synergistic mechanism and environmental behavior of tank-mix adjuvants to topramezone and atrazine.

An effective way to reduce herbicide quantity is to use adjuvants in order to optimize the amount of herbicide and improve its control efficiency. In order to screen for efficient herbicide tank-mix adjuvants, improve the control of weeds in maize fields, reduce the amount of effective ingredients, and improve the adsorption and digestion behavior of herbicides in soil, this study evaluated the synergistic effects and soil behavior of four types of tank-mix adjuvants combined with herbicides. Different types of adjuvants can enhance herbicide production. Surface tension was significantly reduced by 13% after the pesticide solution was applied with AgroSpred™ Prime. The contact angle with the foliar surface was significantly reduced and solution wettability improved using Atp Lus 245-LQ-(TH). The permeability of topramezone and atrazine in leaves of Amaranthus retroflexus L. and Digitaria sanguinalis (L.) Scop. was increased by 22-96% after adding either tank-mix adjuvant. The solution drying time and maximum retention on leaves were not affected by the tank-mix adjuvants. Ethyl and methylated vegetable oils can reduce the adsorption of topramezone in the soil, thus reducing its half-life in soil. The tank-mix adjuvants had no significant effect on soil dissipation or adsorption of atrazine. AgroSpred™ Prime and Atp Lus 245-LQ-(TH) have the best synergistic effect on topramezone and atrazine in the control of A. retroflexus L. and D. sanguinalis (L.) Scop. in maize fields.

Detection and mapping of Amaranthus spinosus L. in bermudagrass pastures using drone imagery and deep learning for a site‐specific weed management

AbstractWeed encroachment negatively affects pasture productivity by reducing herbage allowance, stocking rates, and livestock performance. Amaranthus spinosus L. is a weed species widely found in pastures worldwide and is considered challenging for ranchers due to its great potential for invasion, making it difficult to control. The high costs of chemical application and the global concern about environmental impacts restrict indiscriminate herbicide spraying in pastures. Site‐specific weed management (SSWM) is a weed management strategy based on weed spot‐spraying that has the potential to overcome these issues. Images from unmanned aerial vehicles (UAVs) can provide valuable information for weed mapping to drive the herbicide application in pastures. Deep learning techniques have been highlighted in image classification tasks. We developed a deep convolutional neural network (CNN)‐based image segmentation model based on the U‐Net architecture to detect and map Amaranthus spinosus in bermudagrass pastures using red–green–blue images acquired through UAV flying in moderate‐high altitude. The images were acquired from twelve paddocks under three treatments (weed‐free, weed‐strips, or weed‐infested) during the summer (2021‐2022). The CNN model was able to detect around 80% of the A. spinosus with an average prediction accuracy of 94%. Our weed mapping showed the potential of using the U‐Net model to generate a herbicide application map to be inserted into the sprayer system, reducing up to 76% of the amount of herbicide applied. Further studies are encouraged to increase the robustness of the model across species and development stages and develop sprayer systems to implement the spot‐spraying in field conditions.

The selected agrotechnical factors affecting the occurrence of black grass Alopecurus myosuroides in winter wheat crops in north-western Poland

Alopecurus myosuroides of the family Poaceae is a highly competitive species for winter cereal crops, particularly for barley and wheat, less frequently for root vegetables or rapeseed. This study aimed to determine the predominant factor or group of factors affecting the cover of A. myosuroides in winter wheat field depending on the tillage systems, time, and amounts of herbicides used. The following variables differentiating the quantitative contribution of A. myosuroides in the analyzed fields were assumed: plough or no-plough tillage, date of biocidal application, and the total amount of herbicides (active substances) used. When spring-only herbicide was applied, the lowest A. myosuroides cover, not exceeding 25%, was observed in the margins of winter wheat fields. The coverage of A. myosuroides, reaching 25–100% of the winter wheat area, regardless of the tillage system, was found when the herbicides from the group of sulfonylurea derivatives (acetolactate synthase ALS inhibitors) were frequently used. Winter wheat infestation with A. myosuroides was significantly lower when ploughing was applied. The highest cover of A. myosuroides, reaching 50–100% of the area, was observed only in the central part of the analyzed winter wheat fields, following the application of herbicides in autumn and spring or in autumn only.

Tolerance of Hymenaea stigonocarpa mart. Ex Hayne. To glyphosate.

Hymenaea stigonocarpa Mart. ex Hayne has leaves with adaxial and abaxial epidermis covered by a very thick cuticle, in addition to anatomical structures involved in reducing the amount of herbicide absorbed by plants. Thus, we tested the hypothesis that H. stigonocarpa is potentially resistant to the herbicide glyphosate, exposing the plants to different doses (0, 96, 240, 480, and 960 g a.e ha-1). We carried out assessments of the symptoms, anatomy, growth and physiology of the plants and found that exposure to glyphosate negatively affected the height and number of leaves of the plants. Leaf fall resulted in a reduction in the photosynthetic capacity of plants, which responded by investing in stem diameter. Despite this, no visual symptoms of glyphosate toxicity were observed at the concentrations evaluated and histochemical tests did not detect signs of oxidative stress in the leaves, nor starch accumulation, indicating that carbohydrate translocation was not impaired. These results confirm our hypothesis of tolerance of H. stigonocarpa to glyphosate. Furthermore, plants exposed to the lowest doses of glyphosate (96 and 240 g ha-1) showed good growth, photosynthesis, transpiration and photochemical potential responses, indicating a hormetic effect in this application range.

Comparing herbicide application methods with See & Spray™ technology in soybean

Abstract New machine-vision technologies like the John Deere See & Spray™ could provide the opportunity to reduce herbicide use by detecting weeds and target-spraying herbicides simultaneously. Experiments were conducted for 2 yr in Keiser, AR, and Greenville, MS, to compare residual herbicide timings and targeted spray applications versus traditional broadcast herbicide programs in glyphosate/glufosinate/dicamba-resistant soybean. Treatments utilized consistent herbicides and rates with a preemergence (PRE) application followed by an early postemergence (EPOST) dicamba application followed by a mid-postemergence (MPOST) glufosinate application. All treatments included a residual at PRE and excluded or included a residual EPOST and MPOST. Additionally, the herbicide application method was considered, with traditional broadcast applications, broadcasted residual + targeted applications of postemergence herbicides (dual tank), or targeted applications of all herbicides (single tank). Targeted applications provided comparable control to broadcast applications with a ≤1% decrease in efficacy and overall control ≥93% for Palmer amaranth, broadleaf signalgrass, morningglory species, and purslane species. Additionally, targeted sprays slightly reduced soybean injury by at most 5 percentage points across all evaluations, and these effects did not translate to a yield increase at harvest. The relationship between weed area and targeted sprayed area also indicates that nozzle angle can influence potential herbicide savings, with narrower nozzle angles spraying less area. On average, targeted sprays saved a range of 28.4% to 62.4% on postemergence herbicides. On the basis of these results, with specific machine settings, targeted application programs could reduce the amount of herbicide applied while providing weed control comparable to that of traditional broadcast applications.

Public acceptance and sustainability perceptions of food produced with chemical, digital and mechanical weed control measures

This study investigated public acceptance and perceptions of the sustainability of food produced with different weed control measures. An online survey with a within-subject design was conducted with 485 respondents from the French- and German-speaking parts of Switzerland. Acceptance of food produced using the investigated measures and social, economic and environmental sustainability perceptions were assessed for full-surface herbicide spraying, herbicide reduction (spot spraying, precise spraying) and herbicide-free mechanical technology (hoeing machine). The importance of food’s naturalness, chemophobia, perceptions of farmers and sociodemographic variables were also recorded. The results revealed changes in social, economic and environmental sustainability perceptions based on the weed control measures, indicating that laypeople assess the impacts of these measures based on their type (chemical, digital, mechanical). The amount of herbicide sprayed is relevant for people’s judgements, as well as the precise spraying that keeps crops intact. The use of hoeing machine is perceived to be the most sustainable, natural and acceptable compared to the other investigated measures. Overall, the findings suggest that communicating information on weed control measures, the quantity of herbicide applied and the precision of the spraying might help increase public acceptance of plant protection measures applied by farmers, promoting sustainability.

Применение микробных биотехнологий для устранения в почве остатков гербицидов классов имидазолинонов и сульфонилмочевин (обзор)

The review is devoted to the problems of application of modern imidazolinone and ulfonylurea herbicides, as well as to the researches in the field of microbial iotechnology for remediation of contaminated soils. Data on the traits of the influence of residual amounts of herbicides from the classes of imidazolinones and sulfonylureas on target and subsequent crops in crop rotations are given in the article. The problems of monitoring of herbicide residues due to the variety of properties of components and decomposition mechanisms in the soil are shown. Ecological aspects of the influence of imidazolinones and sulfonylureas on soil microbiota and non-target organisms are considered. The results of studies of the biodegradation pathways of herbicide components, as well as conditions that contribute to the acceleration of destructive processes, are presented. The relevance of the search for microorganisms-destructors of imidazolinones and sulfonylureas for the production of biological products is substantiated. Microorganisms of different genera, such as Rhodococcus, Rahnella, Pseudomonas, Bacillus, Methylopila, Ancylobacter, Hansschlegelia, Klebsiella, and Arthrobacter, possess destructive potential against imidazolinones and sulfonylureas. The current data on the development of biological products to eliminate residues of imidazolinones and sulfonylureas in soils to reduce the phytotoxic effect are given.

Weed Coexistence in Eucalyptus Hybrid Stands Decreases Biomass and Nutritional Efficiency Mid-Rotation

Determining the period of weed coexistence with eucalyptus stands assists in the integrated management of weed competition, which reduces the application of herbicides, economic costs, and environmental damage. Therefore, the objectives of the present study were to evaluate the impact of a hybrid stand of Eucalyptus grandis × Eucalyptus urophylla trees on biomass production, the concentration and stock of macro and micronutrients, and the efficiency of nutrient utilization under different periods of coexistence with weeds. Our study is the first to report the impacts of weed management on the biomass and nutrients present in the leaves, branches, stembark, and stemwood at the time of mid-rotation (4.5 years old). The experiment was carried out in southern Brazil in the Pampa biome and followed a randomized block design, with three replications. The treatments consisted of increasing periods of coexistence with or control of weeds. The total biomass in the coexistence up to 378 days treatment was 53.7 Mg ha−1, and in the control treatment up to 168 days, it was 81.4 Mg ha−1, differing statistically. This reduction was in the order of 34%. The continuous presence of weeds led to a significant reduction in the production of wood and total biomass. The highest nutrient utilization efficiency (NUE) was observed for wood. The control of weeds for up to 168 days promoted greater productivity than controlling weeds for 378 days. This recommendation can be adopted by plantation managers for this region, reducing the amount of herbicide applied on the stand.

The Effect of Conventional and Nanoformulation Herbicide on Sphagneticola Trilobata

The conventional herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) provide substantial risk to the environment such as contamination of soil and groundwater. The overuse application of conventional herbicide can leave harmful residues in soil and be washed off as runoff, thus causes toxic effect to nontarget organism. For instance, MCPA can cause toxicity to the freshwater organisms such as Daphnia magna and alga Selenastrum capricornutum. Zinc oxide as nanomaterials that are intercalated with 2-methyl-4-chlorophenoxyacetic acid (ZMCPA) herbicide may be useful to resolve the problems associated with MCPA. Nanoherbicide are known to provide a better penetration of active substances hence reduces the amount of herbicide to be applied. The nanostructured herbicide such as ZMCPA could substantially replace the conventional herbicide MCPA if it able to kill the targeted weeds efficiently and have a low risk to the environment. Therefore, it is important to compare the differences of herbicidal activity of MCPA and ZMCPA. The objective of this research is to determine the effects of MCPA and ZMCPA on growth and pigment content of Sphagneticola trilobata. The 2nd objective of this research is to measure the physiological effect and effectiveness of herbicidal activity between the conventional and nanoformulation against Sphagneticola trilobata. The preliminary study was conducted to determine a minimal concentration for MCPA to exert its effect on Sphagneticola trilobata. Then, in the main research, Sphagneticola trilobata was exposed to different concentrations of MCPA and ZMCPA in low, medium and high concentrations. The effect of MCPA and ZMCPA on growth and pigment content of Sphagneticola trilobata was observed at 7, 14 and 21 days, respectively. The results indicated there were no obvious differences in plant growth and pigment content observed between treatment of MCPA and ZMCPA at the same exposure concentration at 7, 14 and 21 days, respectively. MCPA showed higher herbicide efficacy than ZMCPA. HIGHLIGHTS Nanoherbicide Development: The intercalation of zinc layered hydroxide (ZLH) with MCPA resulted in ZMCPA, a nanoherbicide with improved delivery and penetration capabilities compared to conventional herbicides. Potential Replacement for Conventional Herbicides: Nanostructured herbicides like ZMCPA have the potential to replace conventional herbicides like MCPA due to their numerous benefits in addressing issues associated with traditional herbicides. Comparable Herbicidal Effectiveness: The study evaluated the herbicidal activity of MCPA and ZMCPA on Sphagneticola trilobata and found that both formulations inhibited the growth of the weed to a similar extent after 7, 14, and 21 days, indicating comparable efficacy between the conventional and nanoformulation herbicides. GRAPHICAL ABSTRACT

A contractor comparison of novel IPT tools and techniques for Brazilian peppertree (Schinus terebinthifolia) management

AbstractBrazilian peppertree (Schinus terebinthifolia Raddi) is a multistemmed shrub or small tree from South America that is invasive in Florida, Texas, Hawaii, and Australia. It forms multistemmed trunks with spreading branches that create dense thickets. State agencies in Florida manage it at annual costs of over $3 million, and individual plant treatment (IPT) techniques are widely used for control. Recent research testing novel hack and squirt approaches with aminopyralid and aminocyclopyrachlor and basal bark treatment with a new triclopyr formulation has shown these treatments are highly effective. However, they have not been evaluated at larger scales, which would be useful to land managers. Therefore, our objective was to compare the reduced hack and squirt technique using aminopyralid and aminocyclopyrachlor herbicides to basal bark treatment with triclopyr on a field scale. We used two contractor crews to apply treatments to twenty-four 0.2-ha plots. Treatments included aminocyclopyrachlor (120 g L−1) or aminopyralid (120 g L−1) applied with the reduced hack and squirt technique and triclopyr ester (108 g L−1) and triclopyr acid (34 g L−1) formulations applied with two basal bark treatment techniques. We confirmed that reduced hack and squirt significantly reduced the amount of herbicide and carrier applied compared with the basal bark treatments. By 540 d after treatment, aminocyclopyrachlor more effectively controlled S. terebinthifolia than aminopyralid with reduced hack and squirt and resulted in control comparable to that seen with either triclopyr basal bark treatment. These results verify reduced hack and squirt treatment with aminocyclopyrachlor and basal bark treatment with triclopyr acid as alternatives to basal bark treatment with triclopyr ester. Both resulted in significantly less herbicide use with comparable efficacy. This operational research approach has accelerated our understanding of novel IPT strategies and their implementation in the field.

Weed Detection Using Image Processing

Abstract: This project focuses on the development of an image processing based system for the detection of weeds in agricultural fields. The proposed system uses computer vision techniques to extract relevant features from the images of the field and classify the presence of weeds in the field. The system involves pre-processing of the image to remove noise and enhance the quality of the image, followed by segmentation to extract the regions of interest. The features extracted from the segmented regions are then used to train a classification model that can identify the presence of weeds in the field. The proposed system is expected to help farmers in identifying the presence of weeds in their fields accurately and quickly, thereby reducing the amount of herbicides used and increasing crop yield.

تأثير التوزيع الحقلي للكتان ومستخلص السفرندا ومبيد Quizalofop-p-Tefuryl في الادغال المرافقة له وبعض مؤشرات النمو

A field experiment was carried out during the winter season for the year 2021-2022 at the Agricultural Research Station A of the Field Crops Department - College of Agricultural Engineering Sciences- University of Baghdad/ Al-Jadriya. To determine which of the plant densities has the most influence on the weeds associated with the flax crop (Syrian local variety). And to determine the best effect of the Johnson grass (sorghum halepance L.) weed extract, whether alone or in combination with the used Quizalofop- p- Tefuryl herbicide, and to use it in integratTed weed control programs to reduce dependence on herbicides in weed control, Reduce environmental pollution by these herbicides, According to the design of the Randomized Complete Block Design (RCBD). In the order of split plot and with three replications, Such as the first factor, the distance between the row (20, 25, and 30) cm that represents the main plots. Then, the second factor is Control treatments which represent the subplots, (weed free (T1), application Quizalofop-p-Tefuryl at a rate of 2 mL commercial substance (T2), Recommended application rate, Johnson grass extract (stem and leaves) at a rate of 18 L (T3), half the amount of herbicide + half the amount of extract (T4), weedy (T5)). The results showed the following: The distance of 20 cm achieved the lowest dry weight of the weed and the highest average inhibition of 134.57 g/m2 and 49.91%, respectively. While the distance of 30 cm achieved the highest plant height of 78.63 cm, the highest number of main branches in the plant amounted to 5.162 branch/ plant. The highest weight Dry flax plants amounted to 355.21 g/m2. Moreover, the highest percentage of oil was 38.524%. The treatment (T2) achieved the lowest dry weight of the weed and the highest percentage of inhibition amounting to 138.87 g/m2 and 49.91%, respectively. The highest plant height reached 76.92 cm, the highest number of main branches in the plant amounted to 5.158 branch/ plant, and the highest dry weight of flax plants reached 5.158 branch/ plant. 398.61 g/m2 and the highest percentage of oil was 37.35%. The effect of the interaction between the two study factors was significant in most of the traits under study. As the distance of 20 cm with the T2 treatment achieved the lowest dry weight of the weed amounted to 124.53 g/m2 and the highest inhibition rate of 52.35%. While the interaction between the distance of 30 cm and T2 achieved the highest plant height of 80.04 cm, the highest average number of main branches reached 5.833 branch/ plant, and the highest dry weight of flax plants reached 398.61 g/m2 and achieved the highest percentage of oil amounted to 39.847%.

Adsorption Behavior and Residue Degradation of Triazine Herbicides in Soil Amended with Rice Straw Biochar

The removal of or decrease in pesticide residues in soil has attracted considerable attention, due to the serious pollution of pesticides in soil. The purpose of the study was to explore the adsorption behavior of biochar on pesticides and the impact on the degradation of pesticide residues in soil, providing a basis for the remediation of soil by biochar. Biochars were prepared via pyrolysis of rice straw at a high temperature (300 °C, 400 °C, 500 °C, 600 °C). The individual and competitive adsorption of three triazine herbicides, prometryn, atrazine, and simazine, on biochar was investigated, and the degradation of the herbicide residues in biochar-added soil was determined. The selected herbicides presented similar adsorption characteristics to rice straw biochar, and the amount of herbicides adsorbed increased with higher preparation temperature and the amount of biochar. The rice straw biochar adsorbed the studied herbicides simultaneously, and the adsorption amount decreased as follows: simazine > atrazine > prometryn. The competition adsorption of the selected herbicides on the biochar presented a lower adsorption affinity than that when they are adsorbed individually. The adsorption isotherm was best fitted by the Freundlich model. The half-lives of prometryn, atrazine, and simazine were 9.8~12.6 d, 5.2~8.1 d, and 3.7~5.6 d, respectively. Biochar addition increased the degradation of the evaluated herbicides in soil. The rice straw biochar could be the potential sorbents that can be implemented for the removal of pesticides.

Discrimination of weeds from sugarcane in Louisiana using hyperspectral leaf reflectance data and pigment analysis

AbstractControlling weeds is a critically important task in sugarcane production systems. Weeds compete for light, nutrients, and water, and if they are not managed properly can negatively impact sugarcane yields. Accurate detection of weeds versus desired plants was assessed using hyperspectral and pigment analyses. Leaf samples were collected from four commercial Louisiana sugarcane varieties, and nine weed species commonly found in sugarcane fields. Hyperspectral leaf reflectance data (350 to 850 nm) were collected from all samples. Plant pigment (chlorophylls and carotenoids) levels were also determined using high-performance liquid chromatography, and concentrations were determined using authentic standards and leaf area. In all cases, leaf reflectance data successfully differentiated sugarcane from weeds using canonical discrimination analysis. Linear discriminant analysis showed that the accuracy of the classification varied from 67% to 100% for individual sugarcane varieties and weed species. In all cases, sugarcane was not misclassified as a weed. Plant pigment levels exhibited marked differences between sugarcane varieties and weed species with differences in chlorophyll and carotenoid explaining much of the observed variation in reflectance. The ratio of chlorophyll a to chlorophyll b showed significant differences between sugarcane and all weed species. The successful implementation of this technology as either an airborne system to scout and map weeds or a tractor-based system to identify and spray weeds in real-time would offer sugarcane growers a valuable tool for managing their crops. By accurately targeting weeds in sugarcane fields that are emerged and growing, the total amount of herbicide applied could be decreased, resulting in cost savings for the grower and reduced environmental impacts.

(.Effect of Quizalofop-p-Tefuryl herbicide in combination with Johnson grass extract on weed control in flax crop (Linum usitatissimum L

A field experiment was carried out to determine the best effect of Johnson grass extract, alone or in combination with Quizalofop-p-Tefuryl herbicide, to achieve the benefit of their integration into weed control programs to reduce reliance on herbicides in controlling weeds, increasing yield and reducing environmental pollution by these herbicides. The randomized complete block design (RCBD) with the split plot arrangement by three replicates was applied, the distance between the rows (20, 25 and 30 cm) represents the main plots. The control treatments : weed-free (T1), application Quizalofop-p-Tefuryl at rate 2 ml/l (T2), Johnson grass extract at rate 18 l/ha (T3), half herbicide amount + half extract amount (T4) and weedy treatment (T5) , represent the sub-plots . The results showed that of distance 20 cm achieved lowest density of companion weeds (52.20 weeds/m2) and highest percentage of weed control (50.42) after 60 days of application, and highest seed yield, oil yield reached 1.781 and 0.675 t/ha, respectively. The distance 30 cm achieved highest number of capsules (14.790 capsules/plant) seeds (8.337 seeds/capsule) and highest weight of 1000 seeds reaching 7.379 g. Application of Quizalofop-p-Tefuryl (T2) achieved lowest weed density (54.78 weeds/m2), highest weed control percentage (52.22) after 60 days of application. Besides, highest number of capsules (14.956 capsules/plant), seeds were (8.580 seeds/capsule), highest weight of 1000 seeds was 7.611 g, and highest seed yield , oil yield reached 1.779 and 0.7113 t/ha, respectively. Distance 20 cm with treatment (T2) achieved lowest number of weeds reaching (44.67 weeds/m2), highest percentage of weed control (57.59) after 60 days of application, highest seed yield, oil yield reached 2.067 and 0.7267 t/ha, respectively. Distance 30 cm and treatment (T2) achieved highest number of capsules (16.05 capsules/plant), seeds (8.580 seeds/capsule) and highest weight of 1000 seeds reaching 7.873 g.

Potential Role of Low-Molecular-Weight Dioxolanes as Adjuvants for Glyphosate-Based Herbicides Using Photosystem II as an Early Post-Treatment Determinant.

Pesticide use cannot be completely abandoned in modern agriculture. Among agrochemicals, glyphosate is one of the most popular and, at the same time, most divisive herbicide. Since the chemicalization of agriculture is detrimental, various attempts are being made to reduce it. Adjuvants-substances that increase the efficiency of foliar application-can be used to reduce the amount of herbicides used. We propose low-molecular-weight dioxolanes as adjuvants for herbicides. These compounds quickly convert to carbon dioxide and water and do not harm plants. The aim of this study was to evaluate the efficacy of RoundUp® 360 Plus supported by three potential adjuvants: 2,2-dimethyl-1,3-dioxolane (DMD), 2,2,4-trimethyl-1,3-dioxolane (TMD), and (2,2-dimethyl-1,3-dioxan-4-yl)methanol (DDM), on a common weed species Chenopodium album L., under greenhouse conditions. Chlorophyll a fluorescence parameters and analysis of the polyphasic fluorescence (OJIP) curve, which examines changes in the photochemical efficiency of photosystem II, were used to measure plant sensitivity to glyphosate stress and verified the efficacy achieved by tested formulations. The effective dose (ED) values obtained showed that the weed tested was sensitive to reduced doses of glyphosate, with 720 mg/L needed to achieve 100% effectiveness. Compared to the glyphosate assisted with DMD, TMD, and DDM, ED was reduced by 40%, 50%, and 40%, respectively. The application of all dioxolanes at a concentration equal to 1 vol.% significantly enhanced the herbicide's effect. Our study showed that for C. album there was a correlation between the change in OJIP curve kinetics and the applied dose of glyphosate. By analyzing the discrepancies in the curves, it is possible to show the effect of different herbicide formulations with or without dioxolanes at an early stage of its action, thus minimizing the time for testing new substances as adjuvants.

Multi-year landscape-scale efficacy analysis of fluridone treatment of invasive submerged aquatic vegetation in the Sacramento–San Joaquin Delta

Invasive aquatic macrophytes are a major threat to estuarine ecosystems globally, posing difficult control challenges for resource managers. This study examined the efficacy of a fluridone treatment program to control invasive submerged aquatic vegetation (SAV). We leveraged four datasets to examine efficacy of fluridone treatment in the Sacramento–San Joaquin Delta, a freshwater tidal estuary in California, from 2014 to 2018. Annual SAV coverage maps derived from spectroscopy data were used in conjunction with fluridone application data and water current speed predicted by a 3-D hydrodynamic model of the study system. Our objective was to determine if the probability of SAV occurrence in treated sites was significantly different from untreated sites. We examined whether efficacy was influenced by the amount of herbicide applied at a site, the local current speed, and the treatment history of the site. We found that treatment efficacy was positively associated with the amount of herbicide applied per unit area, but this effect was mediated by a negative association with current speed. The efficacy of treatment did not improve when a site was treated for multiple consecutive years. Finally, we did not detect legacy effects one year after cessation of treatment. Our results suggest the need for careful selection of treatment sites to ensure that the amount of fluridone applied is likely to have significant impact given local current speeds. Our study underscores the need for development of additional treatment methodologies for hydrologically dynamic systems such as estuaries, particularly when control is needed year-round and for multiple years.

Herbicides widely used in the world: an investigation of toxic effects on Caenorhabditis elegans.

Dicamba, paraquat, picloram, clopyralid and linuron are herbicides widely used in agriculture. The aim of the present study is to evaluate the toxicity effects of the herbicides used on survival, fertility and length of Caenorhabditis elegans. Kaplan-Meier Survival Analysis method was used to identify the toxicity effect of herbicides on survival, and ANOVA and Post Hoc tests were used to determine the toxicity effects on fertility and length. In the study, C. elegans was exposed to 5 different concentrations (62.5, 125, 250, 500, 1000µM) of each herbicide. When the results were evaluated, it was observed that survival (life span) and length (physical growth) were more affected, respectively, by paraquat, dicamba, linuron, picloram and clopyralid herbicides, fertility (egg productivity) were more affected, respectively, by paraquat, linuron, dicamba, picloram and clopyralid herbicides. As a result, it was determined that increasing the dose amounts of herbicides caused many toxic reactions on C. elegans, affecting survival, egg productivity and length.