Dicotyledonous Weeds Research Articles

Towards a true conservation zero tillage system: “A proposed solution based on computer vision to herbicide resistance.”

The Zero Tillage (ZT) or Non-Tillage system constitutes an agricultural production approach designed for improved soil conservation, reduced fossil fuel usage, mitigation of waterway pollution, water and wind erosion, and addressing soil compaction, among other objectives. In this way, ZT promises more sustainable agriculture. However, current ZT production systems depend on herbicide applications for weed control. The use of herbicides with the same modes of action over many years has led to numerous resistant weed species, which end up threatening the success of the herbicide weed control and, consequently, the overall success of the ZT system. Being able to automatically detect and classify weed species directly under the sprayer during the chemical application is an alternative to control populations of weeds since it would allow selecting the herbicide and dose for those particular species. This study, conducted over 15 years in commercial fields utilizing Zero Tillage (ZT) management, examined various ground covers intrinsic to the ZT system originating from previous crops or residues post-harvest. ZT features a broad spectrum of contexts due to the complexity of different ground cover types, which challenge computer vision techniques. The assessment focused on the automatic detection and classification of among the most problematic monocotyledonous and dicotyledonous weed species in the province of Cordoba in Argentina, with the objective of enabling a more targeted and selective approach to their control. These are Amaranthus palmeri, Echinochloa crus-galli, Eleusine indica, Parietaria debilis and Conyza sumatrensis. Additionally, some species belong to the same botanical families with several morphological resemblances that defy vision algorithms. This work proceeded through a machine learning approach applied to computer vision features such as SIFT (scale-invariant feature transform), K-means (clustering), and Bag of Features over the Support Vector Machine for classification. The results showed an accuracy between 89 % and 98 % over the species, allowing a significant reduction of herbicide while applying the adequate active ingredient. Moreover, virtual binary maps from weed patches are devised to be implemented through ISOBUS protocol. Thus the current research contributes significantly to the issue of controlling populations of weeds in the ZT agriculture system.

Screening suitable legumes for living mulches to support nitrogen dynamics and weed control in a durum wheat-forage sorghum crop sequence

Relay intercropping of service legumes (living mulch) is a valuable agroecological practice to support nutrient availability, yield and non-chemical weed control in a crops sequence, if suitable legumes are chosen. This study tested the suitability of eight legume living mulches for relay intercropping in durum wheat (Triticum durum Desf.) evaluating their effects on the subsequent forage sorghum (Sorghum bicolor L. Moench) in a Mediterranean low-input cereal-based cropping system. Legumes include perennial (Medicago sativa, Medicago lupulina, Trifolium repens, Hedysarum coronarium), annual (Trifolium incarnatum, Trifolium resupinatum) and annual self-seeding (Trifolium subterraneum, Medicago polymorpha) species. A plot experiment repeating two times a wheat-sorghum crop sequence, was carried out in Central Italy to assess the effects of relay intercropping of legumes on agronomical and economic performance of the associated wheat and subsequent sorghum. The legumes were undersown in the already developed durum wheat in late winter. They were maintained after wheat harvest and used as green manure by biomass chopping and plowing in the following spring at sorghum sowing time. None of the intercropped legumes affected N uptake or grain protein content of the companion wheat with respect to the control (wheat sole crop). In the spring before sorghum sowing, N input from legume biomass residues was assessed and it sensibly changed according to legume species, ranging from 1.2 (T. incarnatum) to 182 kg ha−1 (H. coronarium). The legume treatments significantly affected the N uptake in the subsequent sorghum and it ranged from 20.2 to 172.6 kg ha−1. Without the use of additional external nitrogen input, average sorghum dry biomass production preceded by H. coronarium (13.3 t ha−1), T. repens (11.8 t ha−1), T. subterraneum (11.0 t ha−1) and M. sativa (9.3 t ha−1) was in line with the productive level under conventional conditions. Biomass residues of M. sativa significantly reduced the total weed biomass in sorghum by 65% compared with the control. In sorghum, preceding legumes such as T. resupinatum and T. incarnatum promoted dicotyledonous weed growth. Hedysarum coronarium and T. repens were the best legumes for relay intercropping in the low-input wheat-sorghum crop sequence under Mediterranean conditions of this study according to agronomic and economic evaluation. These legumes were able to increase soil nitrogen content allowing to significantly reduce external nitrogen fertilization while optimizing sorghum production. When gross income is calculated at cropping system level, most legumes provide a positive economic balance.

Эффективность новых гербицидов на посевах кукурузы в условиях Западного Предкавказья

When studying the effectiveness of using promising herbicides on crops of corn hybrids in the central zone of the Krasnodar Territory, it was found that corn crops are predominantly contaminated with dicotyledonous weeds such as Theophrastus rope, upturned acorn grass, ragwort, white pigweed, self-seeded poppy, and shepherd’s purse. Cereal (monocot) weeds are represented by blue bristle grass, green bristle grass and chicken millet. Perennial weeds include by field bindweed. The most effective herbicide is Adengo in the 1–2 leaf stage, giving a yield increase of 56.1 c/ha. At the same time, corn hybrids in the mid-early group yielded 91.5 c/ha and those in the mid-ripening group 77.1 c/ha. To obtain a corn yield of 100 c/ha, it is necessary to apply the herbicide Adengo (0.5 l/ha) at the stage of 1–2 leaves in the technology of cultivation of its hybrids DKS3969, DKS3 and DKS3789

Evaluation of Dicamba Drift Injury and Yield Loss on Soybean Using Small Unmanned Aircraft Systems (sUAS) and Multispectral Imaging Technologies

Highlights The response of dicamba-susceptible soybean to three simulated rates and growth stages has been studied. Soybean physiological data, such as plant height and phototoxicity, was collected at the selected growth stage. Aerial images of the experiment field using UAV were collected on specific days after treatment. Soybean yield, biological response, and the correlation of vegetative indices in predicting soybean yield were achieved. Abstract. Many dicotyledonous weeds can be selectively controlled by dicamba application during the growing season. However, vapor or spray drift from dicamba application could cause significant yield loss on non-target species such as soybean [Glycine max (L.) Merrill] that do not contain the dicamba resistance trait. In this study, the impact of simulated dicamba drift was investigated on dicamba-susceptible soybeans during different growth stages. A field experiment was conducted employing small unmanned aircraft systems (sUAS) and multispectral image sensors to assess the dose-response relationship between dicamba drift and soybean yield. The experiment followed a randomized complete block design, with main plots representing three distinct soybean growth stages (third trifoliate, sixth trifoliate, and early reproductive stage) and sub-plots encompassing various simulated dicamba drift rates. The analysis, involving non-linear regression and normalized difference vegetation index (NDVI) regression, revealed that visible soybean injuries were observed at minimal dicamba rates. However, significant yield loss occurred during the V6 growth stage at a dicamba rate of 98 g.ai ha-1, emphasizing the critical growth stage sensitivity. Moreover, a moderate yet meaningful relationship (R2 = 0.46) was established between sUAS multispectral NDVI data and soybean yield, highlighting the potential for sUAS with multispectral sensors to predict soybean yield losses. These results contribute valuable insights into the impact of dicamba drift on soybeans and the efficacy of remote sensing technology in assessing yield outcomes. Keywords: Dicamba-drift injury, Multispectral image, Precision agriculture, Soybean yield, sUAS, Yield prediction.

Studying the efficacy of herbicides against annual cereal and dicotyledonous weeds

The harmfulness of annual cereal weeds increases annually. In the Akmola Region, the species composition of weed vegetation, numbering many species and infesting crops, is very diverse and is represented by the following and the most common: Avena fatua (common wild oat), Echinochloa grusgalli (chicken millet), and Setaria viridis (gray mouse). High severity is also observed in lamb’s quarters (Chenopodium album), common beetle (Amaranthus retroflexus), and European stickseed (Lappula squarrosa). The evaluated herbicides include “Dezormon”, “Dezormon Efir”, “Topik”, “Ovsyugen Extra”, combined formulations like “Ovsyugen Extra + Arbalet + Liberti”, “Ester + Ovsyugen Extra”, “Megastar + Efir”, and several others, each demonstrating varying degrees of biological effectiveness, ranging from 76% to 99%. The outcomes indicate that the use of these herbicides significantly mitigates the weediness of the cereal crops, thereby enhancing the grain yield. This study provides valuable insights into the strategic application of herbicide mixtures as a sustainable solution for weed management in cereal cultivation, emphasizing the need for integrated weed control strategies to ensure agricultural sustainability and food security.

NO-TILL ТЕХНОЛОГИЯСЫНДАҒЫ ГЕРБИЦИДТІҢ БИОЛОГИЯЛЫҚ ЖӘНЕ ЭКОНОМИКАЛЫҚ ТИІМДІЛІГІ

The article reveals the biological and economic effectiveness of the herbicide for the no-till technology. The research was conducted in the period from 2019 to 2021 at the experimental no-til field of the Zarechnoye Agricultural Experimental Station LLP in the Zarechnoye village, Kostanay district, Kostanay region. The research purpose is to reveal the effect of herbicides on the resulting crop. Tasks: to study and analyze the average air temperature, precipitation and average humidity (taking into account decades and its average amounts, as well as to determine the biological and economic effectiveness of various dosages of herbicide (2,4-D (2-ethylhexyl ether) 410 g/l + Florasulam 7.4 g/l) against annual dicotyledonous, including those resistant to 2,4-D and 2M-4X, and some perennial dicotyledonous weeds growing on spring wheat crops cultivated using no-till technology at the experimental site of Zarechnoye Agricultural Experimental Station LLP in the Zarechnoye village, Kostanay district, Kostanay region. Harvesting and threshing of the ears were carried out in 2-fold repetition. The harvest was brought to the standard moisture content of the seeds, according to the state standard and is recalculated in c/ha. The article shows detailed peculiarities of weather conditions and the effectiveness of the herbicide against annual dicotyledons, including those resistant to 2,4-D and 2M-4X, and some perennial dicotyledonous weeds growing on spring wheat crops cultivated using no-till technology.

The effectiveness of sulfonylurea-based herbicides against dicotyledonous weed species on spring wheat crops in the Southern forest-steppe of the Trans-Urals

The effectiveness of chemical treatment differs significantly depending on the region and the types of weeds. In this regard, in the Kurgan region in 2018-2020, a comparative assessment of preparations based on sulfonylureas in spring wheat crops was carried out to identify the application features in the conditions of the Trans-Urals. The research was carried out on the experimental field of the Kurgan Research Institute of Agricultural Sciences -of the branch of the FSNSI UrFARC UrB RAS as part of the grain-fallow crop rotation. The purpose of the research was to determine the effectiveness of the use of sulfonylurea-based herbicides in spring wheat crops for the control of dicotyledonous perennial and young weed species. The main task was to determine the herbicide that most completely suppresses weed vegetation and has a positive effect on yield. According to the research results, a good effectiveness of weed control at the level of 74-76% was noted in preparations based on metsulfuronmethyl 10 g/ha, as well as in a mixture of metsulfuron-methyl and tribenuron methyl 12 g/ha. A 64-69% reduction in the mass of weeds was obtained using the tribenuron-methyl and florasulam 30 g/ha variant. The weakest control of weeds was detected in the variant with tribenuronmethyl 20 g/ha (biological efficiency 57%). The tested drugs provided yield increases of +19-24% to the control level.

EFFICIENCY OF APPLICATION OF SOIL HERBICIDES ON SUNFLOWER CROPS

The selection of the optimal scheme for the protection of sunflower crops is always relevant, since the protection of crops from weeds is very important and has a direct impact on the productivity of the crop. The goal is to determine the effect of soil herbicides on weediness of sunflower crops. Determining the effectiveness of various options for herbicide protection. Applied materials and methods: field experiment, laboratory, analysis, processing and generalization of data. The results of the application of different options of herbicide protection on the yield of sunflower of the right-bank forest-steppe of Ukraine are presented. It was determined that the experimental plots had a small-year type of weeding and an average degree of weeding. Among chemical protection, the best efficiency was recorded when using the soil herbicide Challenge at the rate of 5 l/ha, the efficiency compared to the control was 86.7%. It is worth noting that the efficiency of the reference herbicide Primekstra TZ Gold at the rate of 4.5 l/ha was 69.7%. The level of destruction of segetal vegetation on other variants of herbicide use ranged from 65.8% to 78.9% 14 days after application. The use of the drug Challenge at the rate of 2.5 l/ha in combination with Prometrex, Racer and Aspect Pro showed average efficiency and ranged from (61.0 to 55.3%). A decrease in the application rate of the drug Challenge - 2.5 l/ha in tank mixtures led to the growth of dicotyledonous weeds. It was established that the highest yield of 3.8 t/ha has the option of using the soil herbicide Challenge with a rate of 5.0 l/ha. In comparison with the control, an increase of 0.6 t/ha is recorded. A significantly lower level of sunflower productivity was obtained with the introduction of tank mixes Prometrex - 1.5 l/ha + Aspect Pro - 2.0 l/ha and Racer - 1.5 l/ha + Aspect Pro - 2.0 l/ha. A promising direction for further research is the study of the impact of herbicide protection on sunflower productivity and the effectiveness of segetal vegetation.

Very long chain fatty acid–inhibiting herbicides: Current uses, site of action, herbicide-resistant weeds, and future

Abstract The herbicides that inhibit very-long-chain fatty acid (VLCFA) elongases are primarily used for residual weed control in corn, barley, oat, sorghum, soybean, sugarcane, certain vegetable crops, and wheat production fields in the United States. They act primarily by inhibiting shoot development of susceptible species, preventing weed emergence and growth. The objectives of this review were to summarize 1) the chemical family of VLCFA-inhibiting herbicides and their use in the United States, 2) the VLCFA biosynthesis in plants and their site of action, 3) VLCFA-inhibitor resistant weeds and their mechanism of resistance, and 4) the future of VLCFA-inhibiting herbicides. After their reclassification as Group 15 herbicides to include shoot growth-inhibiting herbicides (Group 8), the VLCFA-inhibiting herbicides are currently represented by eight chemical families (benzofurans, thiocarbamates, α-chloroacetamides, α-oxyacetamides, azolyl-carboxamides, isoxazolines, α-thioacetamides, and oxiranes). On average, VLCFA-inhibiting herbicides are applied once a year to both corn and soybean crops in the United States with acetochlor and S-metolachlor being the most used VLCFA-inhibiting herbicides in corn and soybean production, respectively. The site of action of Group 15 herbicides results from inhibition of the VLCFA synthase, which is encoded by several fatty acid elongase (FAE1)-like genes in VLCFA elongase complex in an endoplasmic reticulum. The VLCFA synthase is a condensing enzyme, and relies on a conserved, reactive cysteinyl sulfur in its active site that performs a nucleophilic attack on either the natural substrate (fatty acyl-CoA) or the herbicide. As of August 2023, 13 weed species have been documented to be resistant to VLCFA inhibitors, including 11 monocot weeds and two dicot weeds (Palmer amaranth and waterhemp). The isoxazolines (pyroxasulfone and fenoxasulfone) are the most recently (2014) discovered VLCFA-inhibiting herbicides. Although the intensity of VLCFA-inhibitor-directed discovery efforts has decreased over the past decade, this biochemical pathway remains a viable mechanistic target for the discovery of herbicide premixes and a valuable component of them.

How Does Sustainable Management Practices Affect Weed Flora and Tuber Yield of Potato Crop in Mediterranean Environment?

AbstractIntensive potato cultivation affects weed species composition by selecting dominant and competitive weeds that represent a constraint of potato productivity. Field experiments were conducted during 2015 and 2016 growing seasons to examine the effects of soil tillage (plowing (PL), spading (SM), sub soiling (SS)) and fertilizer source (mineral (Min) and organic (Org)) on potato yield and weed community under Mediterranean environment. A randomized complete block design with three replications was adopted. Weed density and biomass were measured at the potato harvesting time. Weed density was highest in SS, intermediate in SM, and lowest in PL (43.8, 40.3, and 28.8 plants m−2). Similar trend was observed in weed biomass. Weed density and biomass were higher in Org than Min (42.1 vs. 36.4 plants m−2 and 129.6 vs. 117.9 g m−2, respectively). Perennial, monocot, and dicot weed species were the most abundant in subsoiling (13.1, 9.3 and 34.5 plants m−2). Density of perennial and dicot species were higher in Org than Min. Monocots were mostly linked with Min, while dicots were mainly associated with Org. Although tuber yield was higher in PL and Min (481.9 and 627.5 g m−2 of DM), it was affected by growing season and might be associated to SM and Org. Although the study shows that increased weed biodiversity in the system, achieved with more sustainable practices, proves to be an obstacle to potato production, the adoption of spading machine applied in combination with mineral and organic fertilizers could be a valid alternative to plowing. Further studies are required to develop sustainable agricultural techniques able to improve the competitive capacity of crops and reduce the selection of dominant weed species.

Traits of weed species present in maize respond to tillage and cropping systems

IntroductionArable weeds adapt to any changes in disturbance and management. On arable fields, tilling disturbs the soil, while cropping practices like rotation, pesticide use, fertilizer use, and the use of subsidiary crops characterize the management of the field. On a species level, weeds adapt in their abundance and composition. The species have certain traits to use the on-site resources best. Our objective was to investigate if traits beyond just species describe the adaptation of weeds to tillage and cropping systems. Therefore, we present a use case of weeds on fields cropped with maize in Germany.Material and methodsOver 2 years, we conducted a nationwide weed survey on 577 maize fields. On each field, the abundance of each weed species was counted on 10 randomly sampled square plots of 0.1 m² not treated with herbicides at the fourth to eighth leaf stages of the maize. Weed species frequent on at least 5% of the fields were assigned traits. Traits were taken from published updated databases. We interviewed all farmers about the management practices of their fields.ResultsThe management practice data identified three management clusters of tillage and cropping sequence on maize fields. The standard system so far is a management system characterized by inversion tillage and maize cropped in rotations (“Traditional”). The two transformation systems are maize cropped in rotations but with non-inversion tillage as the method of soil disturbance (“Conservational”) and maize cropped continuously regardless of the tillage system (“Monoculture”). Ordination techniques showed that both weed species and traits are assigned to these management systems. Traditional disfavored weed species with a greater plant height. Conservational selected dicot weed species with a high seed weight and a long flowering duration. Monoculture mainly filtered monocot weed species and favored weeds that germinate in spring.DiscussionOur study describes weed responses on transformations of maize cropping in tillage and cropping systems on both the species and the trait level. This application expresses the importance and value of collecting weed surveys with field management data on a geographically widespread and repeated timescale.

Influence of Long-Term Use of Mineral Fertilizers on Weed Infestation of Grain-Grass-Rowed Crop Rotation

In a long-term study in a long-term stationary experiment, it was revealed that the effect of mineral fertilizers extended to the quantitative composition and structure of the contamination of fields of grain-grass crop rotation, but not to the species composition of weed vegetation. Under the influence of mineral fertilizers, the height and weight of weeds increased, but their number decreased during the period of co-growth with cultivated plants during the growing season (by 12.0–22.6%). In the absence of a pronounced competitiveness of cultivated plants in the non-maneuverable version of the experiment, the weeds from the spring period to the harvest increased by 47%. The contamination of fields with perennial dicotyledonous weed species and their relative abundance in fertilized variants decreased by 2.4–3.6 times, and with small-year dicotyledonous species increased by 1.3–1.4 times. White marjoram and pickles turned out to be responsive to the application of mineral fertilizers, while field thorice and wild radish mainly grew in an untreated version, where the acidity of the soil had higher indicators.

Potential of different common (Fagopyrum esculentum Moench) and Tartary (Fagopyrum tataricum (L.) Gaertn.) buckwheat accessions to sustainably manage surrounding weeds

Twenty-nine accessions of two buckwheat species (Fagopyrum esculentum Moench (common buckwheat) and Fagopyrum tataricum (L.) Gaertn. (Tartary buckwheat) were evaluated for their allelopathic potential against two resistant weeds, the monocot Lolium rigidum Gaud. and the dicot Portulaca oleracea L. The bulking use of synthetic herbicides and their consequent contamination of the environment and resulting increment of herbicide-resistant weeds, imminently requires a solution to achieve sustainable weed management without chemical inputs. The results obtained in this study suggest that buckwheat accessions can sustainably manage weeds through plant interference as competition or allelopathy. This research showed that accessions differ in their potential for sustainably managing both weeds with F. esculentum accessions being more effective against L. rigidum and F. tataricum accessions against both, monocot and dicot weeds. The chemical profile of buckwheat accessions was evaluated to know the content of polyphenols in common and Tartary buckwheat accessions and to know more about their ability to manage weeds sustainably. Differences in the chemical profile between the two buckwheat species were clear. While common buckwheat accessions showed more orientin, vitexin and hyperoside, Tartary buckwheat accessions had higher amounts of rutin, quercetin and kaempferol. We propose that the screening and selection of accessions with strong polyphenol content and vigorous growth can be a step towards organic farming due to its relation to the weed management.

Estimation of efficiency of metribuzin to weeds control in coriander crops

There are no chemicals in Russia to protect vegetative coriander from a complex of dicotyledonous and monocotyledonous weeds. The expediency of using metribuzin for this purpose was assessed. Field small-plot trials with herbicide Zenkor Ultra SC (metribuzin, 600 g/l) were carried out in three agricultural territories with differing climatic conditions: Krasnodar, Omsk and Astrakhan Regions. Weed counts were using the quantitative and weight method. The efficiency of herbicide was calculated to the control without treatment. As a result of trials, three groups of weeds were identified: 1) species highly sensitive to herbicide: Chenopodium album L., Amaranthus retroflexus L., Salsola tragus L. (efficiency 90-95%); 2) species medium sensitivity: Solanum nigrum L., Polygonum aviculare L. (efficiency 50-65%); 3) poorly controlled weeds: Ambrosia artemisiifolia L., Galium aparine L. (efficiency less 30-40%). Increases yield of seeds of coriander variety Yantar after Zenkor Ultra SC use amounted to 26.1-37.3%. Phytotoxicity was noted on varieties Ranniy and Santo in one of the years and this needs future estimation sensitivity of varieties to metribuzin.

Mentha suaveolens as Allelopathic Biomass for Weed Control: Phenolics, Organic Acids, and Volatile Organic Compounds Profiles

The need to find alternatives to synthetic herbicides has led to the evaluation of the use of allelopathic biomass from different agroforestry species as soil amendments for weed control. Mentha suaveolens Ehrh. (apple mint) could be a suitable candidate as an ecoherbicide due to its availability in the agroecosystem, well-studied biological activities, and known chemical composition. For the present study, two greenhouse pot experiments were conducted by incorporating flowering aerial biomass of apple mint into the soil. In the first one, the potential phytotoxic effects of M. suaveolens at doses 1 and 2% were evaluated on the germination and growth of maize and its accompanying weeds. In a second temporary assay, the duration of phytotoxicity and the effects of apple mint (0.5% dose) on the physicochemical properties of the soil were elucidated. The soluble (phenolics and organic acids) and volatile compounds potentially releasable from the allelopathic biomass were identified. The apple mint exerted adverse effects on the germination and growth of dicotyledonous weed species, especially Amaranthus retroflexus and Solanum nigrum, with almost 100% inhibition, as well as on the growth of monocotyledonous weeds such as Digitaria sanguinalis, with a reduction of more than 95%. On the contrary, maize yield and soil properties pH, CECe, organic matter, and exchangeable cations were improved by the ecoherbicide. Chemical analyses of apple mint aerial biomass revealed the presence of 7 phenolic compounds, 9 organic acids, and 32 volatiles. For this study, the effects of incorporating M. suaveolens aerial biomass into soil were evaluated for the first time, and it was demonstrated that it has potential as an eco-friendly plant-based tool for Integrated Weed Management.

Comparative studies of knapsack, boom, and drone sprayers for weed management in soybean (Glycine max L.)

The study titled, "Comparative Evaluation of Knapsack, Boom, and Drone Sprayers for Weed Management in Soybean (Glycine max L.)" was carried out during the Kharif season 2021-22 at an experimental farm affiliated with the Department of Agronomy, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani. The primary objective was to evaluate the comparative efficacy of various sprayers in controlling weeds in soybeans and their work efficiency. The Randomized Block Design (RBD) included ten treatments of pre-emergence (PE) and post-emergence (POE) herbicides applied by knapsack, boom, and drone sprayers. Pendimethalin 30% EC @ 750 g a.i ha−1 was used for pre-emergence herbicide application, and Imazamox 35% EC + Imazethapyr 35% WG @ 70 g a.i ha−1 were used for post-emergence. These treatments were tested on soybean Monocot and Dicot weed count, weed dry weight, weed index, and weed control efficiency. The sprayers were compared for time, water, labor, herbicide, and overall work efficiency. A knapsack sprayer showed the best results for pre- and post-emergence herbicide application, with the lowest weed count, dry weight, control efficiency, and weed index. Boom and drone sprayers followed in effectiveness. Herbicide application was faster with the drone sprayer than with hand weeding, cultural practices, boom sprayer, and knapsack sprayer. Compared to knapsack and boom sprayers, the drone sprayer used less water and labour. Drone sprayers work most efficiently, followed by boom and knapsack sprayers. This study focuses on the prevalence of herbicides and their impact on non-target ecosystems. It aims to develop mitigation strategies by optimizing spraying efficiency and reducing herbicide usage during pre and post emergence. The dissemination of efficient weed management practices that reduce environmental impacts and increase the efficiency of soybean cultivation is consistent with Sustainable Development Goal 15: life on land.

Exploring chemical control of 2,4-D–resistant wild radish (Raphanus raphanistrum) with auxin-related compounds

AbstractSynthetic auxin herbicides were developed and commercialized 60 yr before their mode of action was definitively elucidated. Although evolution of resistance to auxinic herbicides proceeded more slowly than for some other herbicide chemistries, it has become a major problem in the dicotyledonous weeds of many cropping areas of the world. With the molecular characterization of the auxin perception and signaling pathway in the mid-2000s came a greater understanding of how auxinic herbicides work, and how resistance may develop in weeds subjected to repeated selection with these herbicides. In wild radish (Raphanus raphanistrum L.) populations in southern Australia, resistance to multiple herbicides, including synthetic auxins such as 2,4-D, has reduced the number of chemical control options available. The aim of this study was to determine whether compounds involved in auxin biosynthesis, transport, and signaling are able to synergize with 2,4-D and increase its ability to control 2,4-D–resistant R. raphanistrum populations. Although some mild synergism was observed with a few compounds (abscisic acid, cyclanilide, tryptamine), the response was not large or consistent enough to warrant further study. Similarly, alternative auxinic herbicides applied pre- or postemergence were no more effective than 2,4-D. Therefore, while use of auxinic herbicides continues to increase due to the adoption of transgenic resistant crops, nonchemical control techniques will become more important, and chemical control of 2,4-D–resistant R. raphanistrum should be undertaken with alternative modes of action, using mixtures and good stewardship to delay the development of resistance for as long as possible.

Biodegradable amidequats, derivatives of caprylic and pelargonic acids as cationic surfactants for agricultural applications

In this study, we proposed to incorporate natural herbicides i.e. caprylic and pelargonic acids into an amide functional group of a cationic surfactant, thus obtaining amidequats. All the obtained amidequats can be classified as ionic liquids since their melting point values were below 100 °C. Moreover, all compounds were stable up to 166 °C. The obtained ionic liquids exhibited high surface activity, as confirmed by their low CMC values (ranging from 0.02 to 4.32 mmol·L−1) as well as their ability to efficiently lower the surface tension (to 23.8–30.2 mN·m−1). The amidequats, derivatives of caprylic and pelargonic acid exhibited different foam formation ability and its stability depending on their structure. Subsequent tests indicated that amidequats comprising the decyl and dodecyl substituents were readily biodegradable (mineralization at 63–78 % within 10 days). They did not significantly affect the germination of the model monocotyledon plant (sorghum) up to 500 mg·L−1, however, they showed phytotoxicity in relation to the model dicotyledon weed (common sunflower) and displayed low or moderate toxicity towards model microorganisms commonly found in soil, which confirms their low environmental impact.

Sulfentrazone crop safety and efficacy in cabbage and broccoli

AbstractIn 2021 and 2022, research was initiated at two locations to evaluate the efficacy and safety of sulfentrazone in transplanted cabbage and broccoli. Treatments included oxyfluorfen at 560 g ha−1 applied pretransplant (PRE-T), sulfentrazone applied at 116 or 233 g ha−1 PRE-T, and S-metolachlor applied at 715 g ha−1 immediately after transplanting (POST-T) followed by (fb) oxyfluorfen applied at 210 g ha−1 postemergence (POST) 14 d after planting (DAP). The weedy cover of nontreated plots averaged between 6% (14 DAP) and 72% (42 DAP); all herbicide-treated plots averaged less than 30% cover at 42 DAP. At 14 and 28 DAP, oxyfluorfen, S–metolachlor fb oxyfluorfen, and the high rate of sulfentrazone reduced total monocotyledonous and dicotyledonous weed densities by 62% and 100%, respectively, relative to the nontreated control. The density of hairy galinsoga (in New Jersey) and combined ladysthumb and prostrate knotweed (in New York) were reduced by 71% to 99%. Except for the low rate of sulfentrazone, all herbicide treatments reduced weed biomass at harvest by ≥88%. Crop injury varied in response to herbicide treatments or weed competition but was also affected by crop and location. Between 14 and 28 DAP, the greatest amount of stunting (22%) was noted in the S-metolachlor fb oxyfluorfen treatments at both locations. Averaged over treatments, greater stunting was observed in broccoli than in cabbage in New York, whereas stunting estimates were higher for cabbage in New Jersey. All treatments in New Jersey resulted in significantly increased cabbage yield and broccoli and cabbage head sizes relative to the nontreated controls. No yield difference was noted between herbicide treatments and the nontreated check in New York. Data derived from these studies will be used to enhance crop safety recommendations in northeastern U.S. production environments for sulfentrazone used PRE in transplanted cabbage and support a potential label for broccoli.

Effectiveness of graminicide application in chickpea crops in the Eastern Forest-Steppe of Ukraine

Goal. To determine the effect of herbicides, in particular graminicides with different active ingredients, on the weediness of crops and the yield of chickpea seeds in the conditions of the Eastern Forest-Steppe of Ukraine.
 Methods. Field, measuring and weighing, statistical.
 Results. Under conditions of the Eastern Forest-Steppe of Ukraine, 27 species of weed plants were found in chickpea crops (annual cereals — 3 species, annual dicots — 17 species, perennial dicotyledonous — 7 species). Annual cereal weeds dominated in number (76.4%), and annual dicot weeds (44.3%) in terms of raw mass. The highest technical efficiency against annual cereal weeds, when applied during the budding stage of chickpea, was provided by the graminicide Lemur, EC (hyzalofop-P-tefuryl, 40 g/ l) — 1.5 l/ ha (by the number and raw mass of cereals, 99.2 and 98.3%, respectively), and the lowest efficiency was provided by the graminicide Selenite, EC (clethodim, 120 g/ l) — 1.0 l/ ha (79.4 and 71.8%, respectively). Tank mixture of soil herbicides Panda, EC (pendimethalin, 330 g/ l) — 3.5 l/ ha + Steals, EC (flurochloridone, 250 g/ l) — 2.0 l/ ha, which was applied in the pre-emergence period, controlled only the number of annual dicot weeds (technical efficiency was 62.1—79.0%), which was associated with a number of factors (the presence of resistant weed species in the crops, different soil moisture during the application period by years, the use of the minimum recommended doses of herbicides). The studied herbicides did not affect perennial dicot weeds. Combining soil herbicides with graminicides reduced the total number of weeds by 73.2—87.9%, and their raw weight by 22.4—43.0%. The highest economic efficiency (0.28 t/ ha) was provided by the composition of the preparations Panda, EC — 3.5 l/ ha + Steals, EC — 2.0 l/ ha (tank mixture) + Queen Star Max, EC (hyzalofop-P-ethyl, 125 g/ l) — 0.8 l/ ha.
 Conclusions. In the absence of the effect of the studied herbicides on perennial dicot weeds and the insufficient effect of soil herbicides on annual dicot species, despite the high effectiveness of graminicides against cereals, it was not possible to obtain significant increase in the yield of chickpea seeds (from 0.13 to 0.28 t/ ha).