Cirsium Arvense Research Articles

Weed management in organic dryland wheat production in the Pacific Northwest

AbstractGrowth in demand for organic small grains has increased interest in producing certified organic crops in the semiarid US Pacific Northwest. The region is well‐suited for small grain production, and there is a strong market for organic food products on the US West Coast. However, many growers encounter significant and persistent challenges with weed management, particularly management of perennial weeds such as Canada thistle [Cirsium arvense (L.) Scop.] and field bindweed (Convolvulus arvensis L.), but also common winter and spring annual grass weeds including cheatgrass (Bromus tectorum L.) and wild oat (Avena fatua L.). Coupled with the need to minimize soil disturbance, weed management can become nearly intractable and production limiting. From 2004 to 2024, several short and intermediate studies have been conducted to assess weed control tactics and crop rotation effects on weed management. Lessons learned include incorporating alfalfa (Medicago sativa L.) and spring barley (Hordeum vulgare L.) into rotations for suppression of field bindweed, or alfalfa and winter triticale (x Triticosecale Wittmack) for suppression of Canada thistle. Optimization of cultural inputs, particularly seeding rate, are critical for each crop in rotation. Animal integration and new crops such as quinoa (Chenopodium quinoa Willd.) are alternatives to conventional crops and potentially profitable. Incorporation of precision mechanical and chemical systems is feasible in narrow‐row cereals, and when combined with crop rotation, it could reduce or eliminate the need for repeated transitions back to convention production for organic growers.

Interactions between Weeds, Pathogen Symptoms and Winter Rapeseed Stand Structure

Rapeseed, weeds, and pathogens interact with each other. However, these interactions are not well understood. The aim of our work was to describe the relationships between weed vegetation and pathogen manifestations in rapeseed stands. Results from the four seasons show that different rapeseed stand structures produce different weed and pathogen responses. Eighteen weed species were identified in the rapeseed stands. The selected characteristics of rapeseed stands, pathogens, and weed manifestations were evaluated using redundancy analysis. Rapeseed stands with the highest levels of pathogens present (Alternaria brassiceae (Berk.) Sacc., Botrytis cinerea (De Bary) Whetzel, Sclerotinia sclerotiorum (Lib.) de Bary, Verticilium longisporum (C.Stark) Karapapa, Bainbr & Heale) had the lowest seed yield. There, the weeds Cirsium arvense (L.) Scop., Tripleurospermum inodorum (L.) Sch. Bip., Sonchus arvensis L. were more abundant in dense stands, and Phoma lingam (telomorph: Leptosphaeria maculans Ces. & De Not.) was more common. Mutual positive interactions may also include the relationship between weed species of the Asteraceae family and increased manifestations of Phoma lingam. A similar relationship can be expected for the weeds Capsella bursa-pastoris (L.) Medik., Descurainia sophia (L.) Prantl and Sclerotinia sclerotiorum symptoms.

Deep learning for image-based detection of weeds from emergence to maturity in wheat fields

Effective weed control in wheat (Triticum aestivum L.) fields is crucial for optimizing production and ensuring food security in semi-arid regions. The implementation of deep learning for weed detection could enable precise weed management, leading to enhanced wheat yield, increased income for growers through targeted herbicide use, and a reduced environmental footprint associated with herbicide application. Charlock mustard (Sinapis arvensis L.) [CM], creeping thistle (Cirsium arvense (L.) Scop) [CT], and forking larkspur (Consolida regalis Gray) [FL]) are among the most invasive weed species in wheat fields. Effective management of these weeds is essential to ensure optimal wheat productivity in the semi-arid regions. To detect weeds, an unmanned arial vehicle was used to collect images and videos from 185 wheat fields in Tokat, Turkey. The images were collected from five phenological periods of each species including seedling, rosette, vegetative, flowering, and fruiting (in total 15 classification process). These stages are either important for timely weed control or essential for understanding weed pressure threshold, the potential for increasing weed seedbank increase, and identifying herbicide resistant weeds. A total of 145,792 objects were labeled in the images to create the dataset, divided into 80 % for training + validation and 20 % for testing. The dataset was used with the YOLOv5 (You Only Look Once) deep learning architecture. The YOLOv5 was the newest YOLO model during this study carried out. All neural networks provided by YOLOv5 (nano, small, medium, large, and xlarge) were trained and the Precision, Recall, F-1 Score, and AUC (Area under the Curve) performances of the neural networks were evaluated. The YOLOv5s (small) was the most precise neural network in detecting weeds regardless of the species. In contrast, nano was the least precise neural network in detecting each weed species. For CT, when small neural network was used, precision of detection ranged from 0.87 (fruit stage) to 0.96 (rosette and vegetative stages). For, forking larkspur, the best neural network was achieved with YOLOv5 small and the precision ranged from 0.45 (fruit stage) to 0.93 (vegetative stage). Using YOLOv5 small in Charlock mustard, the most precise detection occurred at seedling, rosette, and vegetative stages (with precision of 0.96) and the least precise detection was recorded at the fruit stage (0.81). Other performance evaluations (Recall, F-1 Score, and AUC) were in agreement with those of Precision. Our results indicated that by using YOLOv5 small neural network, all three weed species could be detected at all growth stages with the precision of 0.86 with the exception of fruit stage. Future research should (1) focus on assessing YOLOv5 small neural network with the newest versions of YOLO and also (2) evaluate this neural network for detecting weed species in wheat fields to allow for improved weed control and future recommendations.

Combining a field experiment and literature to model the regrowth probability of perennial storage organs fragmented by tillage: Case study of Cirsium arvense (L.) Scop

Management of perennial weeds has become increasingly difficult with the reduction of herbicide use. Creeping perennials accumulate reserves in specialized belowground organs from which they regenerate new plants after a disturbance. Through tool selection, tillage operations could be optimized to reduce perennial-weed reserves and limit regeneration. In the present study, the effect of five tools on the fragmentation of the creeping roots of Cirsium arvense (L.) Scop. (Canada thistle), a major perennial weed in arable crops, were analysed. A field trial was set up to measure the lengths of the root fragments left after tillage. Five tools were tested: mouldboard ploughing, rotary harrow, disc harrow, rigid-tine cultivator and goose-foot cultivator. Fragment-length distribution varied according to the tool: rotary harrow left the smallest (3.7 cm on average) and least variable fragment lengths, mouldboard ploughing the longest (12.7 cm) and most variable ones. The other tools produced intermediate-sized fragments (8–10 cm). Based on these results and literature, a model was proposed to predict perennial-weed regeneration probability from storage-organ fragments after one tillage run. The effects of six factors, which were agronomic (tillage tool), environmental (soil conditions and temperature) and biological (storage-organ fragment diameter, maximal belowground-shoot length and pre-tillage storage-organ distribution), were tested through a sensitivity analysis. According to the model, the probability of fragment regeneration success is lower for the rotary harrow than for the mouldboard plough. The most important drivers of fragment regeneration success were the biological traits: fragment diameter and maximal belowground-shoot length per unit fragment biomass. The present model should be complemented to predict the effect of tillage on perennial-weed regrowth and help improving non-chemical weed-management strategies. To achieve this, further research is needed on plant regrowth potential from storage organs and their architecture in the soil.

Evaluating tiafenacil and tolpyralate for weed control and basal foliage removal in hops

AbstractIn an effort to find alternatives to paraquat for weed control and basal foliage removal in hops (Hummus lupulus L.), due to regulatory and safety concerns, a study was conducted across Oregon and Washington in 2020 and 2021. The study compared the efficacy of tiafenacil and tolpyralate against a nontreated control and carfentrazone. Applications were made early when hops were 2‐ to 3‐m tall (early), and at over 4 m (late). Tiafenacil showed 55%–85% effectiveness in basal foliage control, slightly higher than carfentrazone, and did not cause crop injury. Tiafenacil at 50 and 100 g a.i. ha−1 controlled Lolium multiflorum (Lam.) Husnot (63%). The mixture of tiafenacil and tolpyralate controlled 80% of L. multiflorum, Cirsium arvense L., and Bassia Scoparia (L.) A.J. Scott. In all cases, control was followed by weed regrowth. No signs of crop injury were observed in any of the studies with tiafenacil. Early applications of tiafenacil reduced yield between 0% and 40% relative to the nontreated control. Late applications of tolpyralate and tiafenacil did not significantly reduce yield. Tolpyralate was as effective as carfentrazone for weed control and basal foliage removal. Early applications of tolpyralate reduced plant height and yield relative to the nontreated control and consistently induced phytochemical injury. Tolpyralate yield reductions ranged from 0% to 84% relative to the nontreated control, depending on the trial. A mixture of tolpyralate and tiafenacil was the most effective treatment tested. We conclude that both tiafenacil and tolpyralate are safe for sucker applications in hops, but careful timing is needed to reduce the risk of injury with tolpyralate. The mixture of tiafenacil and tolpyralate can improve weed control comparable to available options.

Cirsium arvense differs from Tussilago farfara in regrowth from intact and fragmented below‐ground systems

AbstractFast regrowth from deep roots and rhizomes makes it difficult to mechanically control the perennials Cirsium arvense and Tussilago farfara respectively. It is, however, not clear whether new shoots originate mainly from fragments of roots/rhizomes in upper soil layers or from an intact system below depth of soil cultivation. Here we present results from three experiments with natural infestations of C. arvense, and two with both C. arvense and T. farfara. Plots of 1 m2 were excavated to different depths (13–25 cm), all below‐ground plant parts in the topsoil were collected and thereafter fragments were either returned to or removed from the plots. Regrowth from disturbed plots with removed or returned fragments was compared. The origin of regrown shoots, that is, whether they originated from seeds, intact below‐ground root/rhizome systems or returned fragments, was examined. More C. arvense shoots originated from the intact root system (48%–84%) than from root fragments (16%–52%). The final aboveground biomass was not affected by removal of the top‐soil fragments. For T. farfara, a small proportion (3%) of new shoots originated from the intact rhizome system, and the rest from fragments. We conclude that the intact root system of C. arvense contributes at least as much as root fragments to regrowth after soil cultivation, which might imply that time of treatment and depth of cultivation are crucial for the effect of mechanical control. For T. farfara, the results suggest that tillage equipment with high capacity to fragment the rhizome system will contribute to efficient control.

Reappraisal of Didymella macrostoma causing white tip disease of Canada thistle as a new species, Didymella baileyae, sp. nov., and bioactivity of its major metabolites

ABSTRACT Bioherbicides are expected to be a supplement to integrated pest management, assisting in the control of problematic weed species. For instance, bioherbicides (Phoma and BioPhoma) were recently registered in Canada and the USA for the control of some perennial dicotyledonous weeds in lawns. These products are based on strains of the fungus Didymella macrostoma (syn. Phoma macrostoma) that causes white tip disease (WTD) in Canada thistle (Cirsium arvense). In this study, WTD was reported for the first time in the Russian Federation. Analysis of the internal transcribed spacer (ITS) region of nuc rDNA and secondary metabolite profiling confirmed the identity of Russian WTD isolates to Canadian biocontrol strains identified as D. macrostoma. Multilocus phylogenetic analysis based on sequencing of the ITS region, partial large subunit nuc rDNA region (28S), RNA polymerase II second largest subunit gene (rpb2), and partial β-tubulin gene (tub2) has differentiated the WTD isolates from C. arvense and D. macrostoma isolates from other plant hosts. Based on phylogenetic, morphological, and chemotaxonomic features, these WTD isolates were described as a new species named Didymella baileyae, sp. nov. This study also demonstrated the low pathogenicity of the ex-type D. baileyae isolate VIZR 1.53 to C. arvense seedlings and its asymptomatic development in the leaves of aboveground shoots. The organic extracts from mycelium and culture filtrate of D. baileyae, as well as macrocidin A and macrocidin Z, displayed phytotoxicity both to C. arvense leaves and seedlings. Macrocidin A was only detected in the naturally infected leaf tissues of C. arvense showing WTD symptoms. Macrocidins A and Z demonstrated low antimicrobial and cytotoxic activities, exhibiting no entomotoxic properties. The data obtained within this study on the pathogenicity and metabolites of D. baileyae may be important for the rational evaluation of its prospects as a biocontrol agent.

Iodide- and electrochemical assisted removal of mercury by Cirsium arvense from gold tailings in the Amansie West District, Ghana

Mercury (Hg) pollution in Ghana through mining has become a serious environmental challenge. This study investigates the potential of Cirsium arvense to photostabilize Hg using electrokinetic current with or without an iodide solution in gold mine tailings heavily contaminated through mining activities in southern Ghana. An initial Hg concentration of 9.60 mg/kg using cold vapor atomic absorption spectrometry (CVAAS) was determined. The biological absorption coefficient, bioconcentration factor, and translocation factor of Hg have been presented. Cirsium arvense therefore had a higher bioconcentration factor (BCF) of 2.6–5.15 mg/kg, and a transfer factor (TF) of 0.24–0.36 indicating a higher efficiency for phytostabilization. Both the rate and time of extractions of Hg from the tailings by Cirsium arvense are efficiently improved in the combined electric current and iodide treatment. Plant and electric current combined treatment and plant and iodide combined treatment had only 60 and 50% phytostabilization rates, respectively. The combined plant, iodide, and electric current treatment has proven to be superior with about >90% Hg removal rate. Therefore, the combined plant, iodide, and electric current treatment resulted in a higher Hg removal efficiency by Cirsium arvense in a shorter period due to higher solubilization rate and electromigration effects on Hg species.

Compositional profiling of the rhizosphere microbiome of Canada thistle reveals consistent patterns across the United States northern Great Plains

Canada thistle is a pervasive perennial weed, causing challenges to agricultural and natural ecosystems globally. Although research has focused on the phenology, genetics, and control of Canada thistle, little is known about the rhizosphere microbiome and the role plant–microbe interactions play in invasion success. This study investigated the rhizosphere microbiome of Canada thistle across diverse climates, soils, and crops in the U.S. northern Great Plains. Soil and rhizosphere samples were collected and bacterial 16S and fungal ITS2 sequencing were performed to characterize the core microbiome and identify potential factors contributing to invasion success. Amplicon sequencing revealed a stable core microbiome that was detected in the Canada thistle rhizosphere across all locations. The core microbiome was dominated by the bacterial phyla Actinobacteriota and Proteobacteria and fungal phyla Ascomycota and Basidiomycota. Differential abundance analysis showed rhizosphere fungal communities were enriched in pathogen-containing genera with a 1.7-fold greater abundance of Fusaria and a 2.6-fold greater abundance of Gibberella compared to bulk soil. Predictive functional profiling showed rhizosphere communities were enriched (p < 0.05, FDR corrected) in plant pathogen fungal guilds which represented 19% of the fungal community. The rhizosphere microbiome was similar in composition across environments, highlighting the stable association between Canada thistle and specific microbial taxa. This study characterized the core microbiome of Canada thistle, and the findings highlight plant–microbe interactions shaping invasive behavior. These findings are important for understanding the ecological impacts of plant invasion and soil-microbe ecological processes.

Influence of temperature conditions of the environment on the dynamics of collecting bee pollen and flower pollen by honey bees

The study conducted at the apiary of the National Scientific Center «P.I. Prokopovych Institute of Beekeeping» in Hadiach, Poltava region, from 2021 to 2023 investigates the dynamics of bee pollen collecting by honey bees of the Ukrainian steppe breed of the Hadiach type. This research focuses on understanding how weather conditions in the forest-steppe zone impact the mass, volume, and size of bee pollen, as well as the botanical composition of the collected pollen. The primary objective of this research is to analyze how different weather conditions influence the collection of bee pollen by honey bees. Specifically, the study aims to assess how variations in temperature, humidity, and other weather factors affect the quantity and quality of pollen collected, and how these factors interact with the flowering periods of key nectar plants. The study utilized hanging pollen collectors to gather pollen from bee colonies between 8 AM and 2 PM. The botanical origin of the pollen was determined through microscopic analysis and international palynological databases. The research focused on several common nectar plants, including red clover (Trifolium pratense), common primrose (Primula vulgaris), cornflower (Centaurea cyanus), common agrimony (Agrimonia eupatoria), field thistle (Cirsium arvense), and common burdock (Carduus acanthoides). Weather conditions were classified into favorable (temperatures of 18–25°C and relative humidity of 57–72%) and unfavorable (cloudy days with northern winds, temperatures below 15°C or above 28°C, and humidity levels outside the 57–72% range). The research revealed that the average mass of bee pollen collected per season varied between 6.3 and 6.6 kg per bee colony. The study found that different plants responded differently to weather condi­tions. For instance, the mass of pollen from red clover ranged from 8.3 to 12.0 mg under favorable conditions, while field thistle showed a decrease in pollen mass during unfavorable conditions. Pollen collection began in mid-April and continued until mid-August. During unfavorable weather conditions, there was a noticeable reduction in pollen mass, which was attributed to lower pollen availability. However, some plants showed better pollen production under adverse conditions. The spring peak in pollen collection, associated with active colony growth, was also influenced by the less diverse summer flora. Temperature data for 2021–2023 indicated that the most favorable conditions for pollen collection varied annually. For example, the cool spring of 2021 delayed bee colony development, while 2022 experienced normal weather conditions. In contrast, 2023 saw active pollen collection during acacia blooming but a reduction duringlime blooming due to insufficient pollen. The study underscores the importance of considering a comprehensive range of weather conditions when evaluating bee colony productivity. The findings highlight that both temperature and humidity significantly impact pollen collection. The results suggest that beekeepers need to account for these variables in their management practices to optimize pollen collection. Further research should explore the interactions between different weather factors and their combined effects on bee foraging behavior and pollen production. Additionally, studies could investigate how changes in climate over longer periods affect bee colony performance and pollen dynamics, providing insights for developing adaptive strategies in beekeeping.

Tillage and crop sequences for organic Cirsium arvense management in the Northern Great Plains

AbstractThe perennial rhizomatous weed Cirsium arvense (L.) Scop. is difficult to manage on semiarid organic farms. Our objective was to quantify the impact of eight 4‐year crop sequences crossed with standard‐ and reduced‐tillage on C. arvense occurrence (presence/absence), stem density, and aboveground biomass at two semiarid sites in Montana. The sequences represented a range of crop competition from high (multiple years of perennial forage [alfalfa, Medicago sativa L.]) to low (2 years of continuous fallow), with intermediate sequences consisting of different annual species. Final‐year spring wheat (Triticum aestivum L. emend. Thell.) was planted in all sequences to determine impacts on subsequent cash crop production. Through time, alfalfa and double fallow sequences reduced C. arvense density and biomass where it was established, although its invasion into new areas increased in the double fallow. Final‐year C. arvense occurrence and stem density were lower in the alfalfa sequence compared with six and four annual crop sequences, respectively (p &lt; 0.05). Final year C. arvense biomass was higher at one site than the other, although not in the double fallow sequence. Wheat grain yields differed in response to crop sequences at the two sites: at one site, grain yield was lowest in the alfalfa sequence, especially when standard‐tillage was used, while yields were highest in the alfalfa and double fallow sequences at the other site. Using perennial forages in semiarid organic systems can be effective for managing C. arvense, but subsequent cash crop yield may be depressed.

ОПЫТ ПРИМЕНЕНИЯ ПЕРСПЕКТИВНЫХ ГЕРБИЦИДОВ В ООО "ФУНДУК АЛАНИИ" ИРАФСКОГО РАЙОНА РСО-АЛАНИЯ

The fight against weeds in crops and plantings of agricultural crops, both annual and perennial, has been and remains one of the most important scientific problems of agricultural production. The relevance of the research lies in a comprehensive study of the effectiveness of the use of modern promising herbicides in hazelnut orchards, in order to optimize measures to combat weeds. The research results made it possible to develop a system for maintaining soil in a walnut orchard using modern herbicides. To solve the problem, it is necessary to conduct geobotanical studies of the weed component in the walnut orchard, to determine the magnitude of the negative impact of various doses of herbicides in the inter-rows and rows of hazel. The authors first obtained data on the use of herbicides on gray forest soils, with alluvial deposits, skeletonized and rocky in the Iraf region of the Republic of North Ossetia, which are characterized by a humus content of 6-8%, phosphorus up to 200 mg/kg, potassium up to 42 mg/kg and acidic reaction of the soil solution (pH 5.1). The object of the study was weeds in perennial walnut plantations, among them difficult-to-eradicate root shoot thistles (Cirsium arvense), (Sonchus arvensis), creeping bitterweed (Acroptilon repens); rhizome creeping wheatgrass (Agropirum repens) and others. It was established that the use of herbicides Lontrel -300, VR (3 l/ha), Hurricane Forte, VR (2 l/ha), Basta, VR (5 l/ha), Sprut Extra VR (3 l/ha) reduced the number of weeds ranging from 84.8% to 89.9%. Recommendations are given on the timing of application of the most promising herbicides in perennial hazelnut plantations. The predominant effectiveness among the herbicides studied was shown by Octopus Extra VR.

How the Management and Environmental Conditions Affect the Weed Vegetation in Canary Grass (Phalaris canariensis L.) Fields

Canary grass (Phalaris canariensis L.) is a versatile crop with global significance; it is primarily cultivated for its small elliptical seeds, which are used as bird feed and for human consumption. This crop is adapted to various climates and soils, so it can be grown successfully in Hungary. However, challenges such as weed control, climate change impacts, and soil factors require strategic management for sustained success in canary grass cultivation. Our study investigated the impact of management and environmental (as seasonal and soil) factors on pre-harvest weed vegetation in canary grass fields in Southeast Hungary between 2017 and 2020. In addition to showing the weed vegetation of the canary grass, the aim of our work was to promote more effective weed management of canary grass by revealing correlations between soil, seasonality, and management variables, influencing weed diversity and coverage. Using the analysis of covariance (ANCOVA) and correlation tests, we tested significant variables, providing insights into the complex interactions affecting weed composition. A redundancy analysis (RDA) further unveiled the relationships between explanatory variables and weed species’ composition. The findings offer valuable information for effective weed management strategies in canary grass cultivation. Our comprehensive study on canary grass fields in Southeast Hungary sheds light on significant factors influencing weed composition and abundance. The average weed coverage was 10.8%, with summer annuals and creeping perennials being the most prevalent life forms. Echinochloa crus-galli, Cirsium arvense, Xanthium italicum, and Setaria viridis were among the dominant species. ANCOVAs revealed the impact of soil, management, and seasonal factors on weed cover, species richness, diversity, and yield levels. Soil properties like texture, pH, and nitrogen content showed varying effects on weed parameters. The vintage effect, tillage systems, and farming practices also played crucial roles. The redundancy analysis highlighted the influence of the year, soil sulfur content, and winter preceding crops on weed composition. In conclusion, the herbaceous vegetation in the studied area is dominated by summer germinating and creeping perennial species. Despite slight differences in average coverage and occurrence, a well-defined set of significant species is evident. Multicollinearity among variables suggests limitations to further increase the number of variables that can be included in the analysis. The ANCOVAs showed that the soil, seasonal, and farming variables significantly influence overall weed vegetation and crop yield, with a lesser impact on species richness and diversity. The reduced RDA model highlights the strong influence of the year on species’ composition, emphasizing the inherent factors during canary grass cultivation that are challenging to modify through farming practices.

Influence of cultivation methods on the soil aggregate state in the context of weed development in winter wheat plantations

Weed control in winter wheat crops is an important issue. There is a risk of increasing populations of certain weed species that are resistant to some of herbicides used for winter wheat crops. This could be controlled by a combination of agronomic, mechanical, chemical, and biological methods. After introducing winter wheat into the rotation and improving tillage, the weediness of regular black soils with perennial root and emerged weeds were significantly reduced. The formation of nodal and rudimentary roots had a significant effect on the productivity of winter wheat under different soil moisture conditions. The highest yield of winter wheat was obtained when sown at the optimum time, with higher stem density and ear productivity due to better grain fullness. We studied what effects did the tillage methods have on the aggregate state of the soil in relation to weed development in winter wheat crops, finding that the structural and aggregate composition of the soil played an important role in winter wheat crops, influencing both the development of the crop root system and the water-physical balance of the chernozem, as well as naturally influencing the course of erosion processes in the experimental plots, and having a universal dynamic in terms of adaptation of aggregation and disaggregation processes. Prolonged mechanical stress on soil can cause destruction of its structure. For instance, continuous ploughing or moldboardless tillage with little or no manure application may permanently reduce soil fertility by increasing humus mineralisation. Subsequently, these factors may cause a significant decline in the soil's structural and aggregate composition, resulting in larger amounts of dusty particles smaller than 0.25 mm and cloddy particles larger than 10–12 mm. The soil's structural condition before sowing winter wheat in early September, on average for 2011–2016, indicates increased dispersion of the tilth layer (0–10 cm) in the experimental variants where shallow disc tillage of 10–12 cm was applied. Increase in the number of clods larger than 10 mm in the areas where moldboardless tillage had been applied can be attributed to significant soil drainage. The soil's aggregate state was rated as good, with 8.7% in the 0–10 cm soil layer and 1.7% of clods &gt; 10 mm in the 0–30 cm layer. In 2014–2016, it was rated as satisfactory, with 7.4% and 9.8% of clods &gt; 10 mm, respectively. Shallow disc cultivation resulted in slightly worse indicators: 6.6% and 8.3% of clods &gt; 10 mm in soil layer 0–10 cm and 0–30 cm, respectively, in 2011–2013; and 7.2% and 6.9% of clods &gt; 10 mm, respectively, in 2014–2016. In general, the parameters of optimal structural condition were positive. The tillage method used had a considerable effect on weed growth and development, particularly for those with a root and rhizome structure. It also affected the prevalence and development of pests and diseases in winter wheat. Agrotechnical methods of weed control do not guarantee complete destruction of weeds. Mechanical moldboardless tillage to the depth of 14–16 cm and disc tillage to the depth of 10–12 cm left the fields with 4.1 to 8.8 annual weeds per square meter and 1.3 to 3.3 specimens of harmful root weeds such as Convolvulus arvensis, Lactuca tatarica and Cirsium arvense. Mechanical moldboardless tillage to the depth of 14–16 cm and disc tillage to the depth of 10–12 cm left the fields with 4.1 to 8.8 annual weeds per square meter and 1.3 to 3.3 specimens of harmful root weeds such as Convolvulus arvensis, Lactuca tatarica and Cirsium arvense. Post-harvest residues (4–5 t/ha) can provide almost complete protection against weeds by covering the soil surface. However, pests and diseases may spread more easily due to preservation of fungal spores on the surface of plant residues and preservation of pest larvae in the straw and soil. The distribution of weed seeds in the soil was altered when the rotational tillage of common chernozems in winter wheat cultivation technology had been replaced with energy–saving minimum tillage (shallow flat-cutting disc tillage). This resulted in the concentration of most of the weed seeds (85–90%) in the upper soil layer (0–10 cm).

Weediness of spring cereal ear crops depends on the forecrop, tillage, fertilizers and herbicides

Goal. To analyze the species composition of weeds, their dominant role and to determine the type and level of weediness of spring cereal ear crops depending on different forecrops, methods of basic tillage, fertilization systems and herbicides in the conditions of the Eastern Forest-Steppe of Ukraine.&#x0D; Methods. The investigations were conducted in field experiments of spring cereal crops (barley, wheat, triticale) in a stationary field, fixed nine-course-fallow-grain-row crop rotation by means of route surveys.&#x0D; results. According to the data of 2016—2018, during the cultivation of spring cereal ear crops in crop rotation after soybeans, corn for grain and sugar beets as forecrops, 38, 34 and 45 species of weeds were identified, respectively. In total, 52 species of weed plants were found in the crops, of which 27 species occurred after all forecrops. The largest number of weeds in agrocenoses was represented by early and late spring species (48.9—58.8%), and the second and third places were respectively occupied by wintering, winter and biennial (26.5—31.1%), and perennial (14.7—20.0%). The main species of weeds in cereal crops were: after soybean forecrop, Setaria glauсa, Echinochloa crus-galli, Chenopodium album, Ambrosia artemisiifolia, Cirsium arvense, Convolvulus arvensis; after corn for grain forecrop, S. glauсa, E. crus-galli, C. album, Amaranthus retroflexus, Solanum nigrum, A. artemisiifolia, Polygonum lapathifolium, C. arvense, C. arvensis; after sugar beets forecrop, S. glauсa, E. crus-galli, C. album, A. retroflexus, S. nigrum, A. artemisiifolia, P. lapathifolium, C. arvense, Sonchus arvensis, C. arvensis. The largest number of weeds (33 species each) was found after sugar beets forecrop in the control (plowing, without fertilizers) and after chisel tillage (manure, after effect 30 t/ha + N30P30K30). Herbicides and forecrops significantly influenced the dominant and subdominant positions of certain weed species. In the crops, the cereal annual-bicotyledonous-root-sprouting type of weediness predominated (44.2%). The type of weediness of the crops depended on the use of agricultural practices in the years of research.&#x0D; Conclusions. In the conditions of the Eastern Forest-Steppe of Ukraine, weediness of spring cereal ear crops depended significantly on the forecrop, the method of basic tillage, the fertilization system, and the use of herbicides.

Grouping of segetal vegetation of winter pea agrophytocenosis and its influence on crop productivity in the Right Bank Forest Steppe of Ukraine

Purpose. To study the species composition and the ratio of seed stocks in the soil of different biological groups of weeds in the agrophytocenosis of winter pea, and their influence on the yield formation depending on the sowing rate of the crop. Methods. Quantitative and weighting, agrochemical, analytical, and statistical methods were used. Results. Weeds that formed a significant seed stock, belonged to the families Chenopodiaceae (58%), Amaranthaceae (18%), Poaceae (9–11%), Brassicaceae (6%), Роlygonaceae (4.5–5.8%), and Asteraceae (1.5–2.2%). A significant raw and dry biomass was formed by Cirsium arvense (52 and 24 g/m2, respectively), Polygonum scabrum (46 and 22 g/m2), Thlaspi arvense (34 and 12 g/m2), Chenopodium album (34 and 14 g/m2), Polygonum convolvulus (27 and 13 g/m2), Sonchus arvensis (23 and 11 g/m2), Amaranthus retroflexus (21 and 10 g/m2), Ambrosia artemisiofolia (22 and 11 g/m2), Solanum nigrum (21 and 9 g/m2), Galium aparine (19 and 8 g/m2), Sinapis arvensis (18 and 8 g/m2), Setaria pumila, and Setaria viridis (9 and 4 g/m2). Conclusions. Changes in the productivity of winter pea at different degrees of weed infestation of the sowings were revealed. A significant influence of segetal vegetation on the crop yield was established at the pea seed sowing rate of 0.6 million seeds/ha, where the yield of the varieties ‘Enduro’ and ‘NS Moroz’ was only 3.01 and 3.13 t/ha, respectively. The density of segetal vegetation at the standard sowing rate of 1.1 million seeds/h and increased rate to 1.6 million seeds/ha did not affect the yield (3.33 and 3.34 t/ha, respectively). On thinned crops, weed infestation increases, which can affect the crop yield, as it has significant advantages for growth and competition with winter pea plants.

Scaling use of the rust fungus Puccinia punctiformis for biological control of Canada thistle (Cirsium arvense (L.) Scop.): First report on a U.S. statewide effort

Canada thistle (Cirsium arvense (L.) Scop., CT) is one of the worst weeds threatening temperate regions of the world. A host-specific rust fungus, Puccinia punctiformis (F. Strauss) Rohl., is known to cause systemic disease of CT, ultimately killing individuals and reducing stand densities. In 2013, it was demonstrated that fall inoculation of rosettes with coarsely ground leaves bearing P. punctiformis telia can successfully initiate epiphytotics. In the same year, a cooperative project between the Colorado Department of Agriculture and United States Department of Agriculture was initiated, in which CT patches across the state of Colorado (USA) were inoculated and tracked over subsequent years for changes in stem density. Here, we report our findings from 8 years (2014–2021) of monitoring effort. At most sites (N = 87), CT stem densities declined, from a mean (±SE) of 87.9 (±6.5) stems to 44.7 (±4.2). These declines however were spatially-autocorrelated, and likely attributable to local growing conditions, as mean annual daily maximum temperature and standard deviation of elevation, as well as climatic conditions around the times of both treatment and monitoring, were found to be important predictors of CT decline. Further, we observed that the amount of inoculum deployed, timing since last release, and method in which it was spread locally at a site were also associated with the magnitude of CT stem decline. These results are indicative of the value of P. punctiformis as a CT biological control agent.

Endophytic genera in californian thistle (Cirsium arvense (L.) Scop.)

Cirsium arvense is an important weed in temperate areas, causing yield losses in pasture and cropping systems. Endophytes may affect fungal biocontrol agents deployed to control C. arvense. This was the first study sampling leaves, stems, and roots of C. arvense multiple times in one growing season to determine which endophytic genera were associated with this plant species. Eighty-eight endophytic genera were isolated by culture methods and identified with molecular markers. Sixty-five of these have not previously been reported for C. arvense. This study was the first to document many genera belonging to the orders Pleosporales, Hypocreales, and Diaporthales that have not previously been identified in association with C. arvense. In addition, this study isolated more Leotiomycetes and Helothiales than previous studies on C. arvense endophytes. Information on endophytic genera in C. arvense will aid our understanding of biotic factors influencing fungal biocontrol agents and may improve effectiveness of biocontrol agents.

Effect of weeds on pea (Pisum sativum) seed germination

Segetal vegetation should be controlled both during crop growing season and after harvesting. The reason is that undesirable vegetation accumulates a significant mass, one that will later become a threat to the following crop in crop rotation. Mixtures of substances of biogenic origin, called allopathic, are constantly changing subject to abiotic factors and environmental conditions. Therefore, their effects on organisms are characterized by significant variability. According to the biotesting results, we found that allopathically active substances of all experimental weed species had a negative effect on pea seed germination. In the control variant, all seeds germinated in 4 days, but in some experimental variants 2–3% of the seeds were in the phase of swelling. Water extracts from different species and parts of weeds had significant inhibitory effect on the germination of pea seeds and further growth. The water-soluble extracts from the underground organs of perennial weeds such as Elytrigia repens L. and Cirsium arvense L. were particularly strong, leading to 58.2% and 53.1% reduction in the length of the embryonic root. Water-soluble extracts from the leaves of these weeds had slightly lower effects on pea germination, and the lags in root growth were 33.5% and 31.4%, respectively. Extracts from weed stems also inhibited pea germination and had an intermediate effect between the effect of water-soluble extracts from the underground part and leaf blades. The effect of extracts from roots of annual weeds on the length of the germinal root ranged 36.6% in common stork’s-bill (Erodium cicutarium L.) to 13.9% in chickweed (Stellaria media L.). The allopathic effect of the substances from the leaves of chickweed (Stellaria media L.) and potato weed (Galinsoga parviflora Cav.) had the lowest effect on the growth of pea root. The lag of the indicator in the control was 7.2% and 12.9% for the variants.

Organic Amendments to Short Rotation Coppice (SRC) Plantation Affect Species Richness and Metal Accumulation of Spontaneously Growing Herbaceous Plants

Excess potentially toxic metals (PTMs) in soils require ad hoc approaches to salvage. Hence, this study explored the shoot accumulation of cadmium (Cd), lead (Pb), and zinc (Zn) by herbaceous plants growing under previously established Salix and Populus clones Short Rotation Coppice (SRC) with compost and sewage sludge applications in an abandoned metallurgical site, Podlesí, Czech Republic; PTM decontamination of soils. Soils within the SRC experimental site and outside considered as control were analyzed for their chemical properties by multi-analytical techniques. Shoots of spontaneously growing herbaceous plants under trees in the site and without trees in control were determined for pseudo-total Cd, Pb, and Zn contents. Moderately to slightly acid soils, high cation exchange capacity, and C/N ratio supported mineralization and relative mobility of total Cd (7.7–9.76), Pb (1541–1929), and Zn (245–320 mg kg−1) in soils. Although soil amendments improved chemical properties, compost application supported higher species richness than sewage sludge. Over 95% of plants accumulated Cd and Zn above the WHO threshold and green fodder in the Czech Republic, with 36% Pb above the regional limit (40 mg kg−1). Approximately 100, 50, and 6% of herbaceous species had Cd, Pb, and Zn accumulation, respectively, higher than published average upper limits in plants (0.2 Cd, 10 Pb, and 150 Zn mg kg−1). Dicots recorded higher Cd content, Tenacetum vulgare (L.), Hypericum maculatum (Crantz), and Cirsium arvense (L.); Stachys palustris (L.), Lamium perpereum (L.), and Campanula patula (L.) for Pb; Glechoma hederaceae (L.), C. patula, and C. arvense for Zn in all treatments. Appropriate soil amelioration of SRC-supported PTM mobility and excess herbaceous species shoot accumulation, growth, and richness.