Continuous cropping leads to declines in soil productivity and biodiversity, as well as a deterioration of overall phytosanitary conditions. What if we rotate the intercrops instead of the main crops? In a stationary three-year field experiment, maize was intercropped with Fabaceae (faba bean, crimson and Persian clovers, and blue-flowered alfalfa), Poaceae (winter rye, annual ryegrass, spring barley, and common oat), and Brassicaceae (white mustard, spring oilseed rape, oilseed radish, and spring Camelina) intercrops in separate growing seasons. Fabaceae intercrops developed slowly and competed poorly with weeds. The highest air-dried biomass (ADM) was produced by Persian and crimson clovers (approx. 86 g m−2). Intercrops of the Poaceae family, particularly rye and oats, as well as ryegrass, which was the most productive at 200 g m−2 ADM, germinated faster and competed effectively with weeds. Brassicaceae intercrops also developed rapidly, especially mustard, Camelina, and radish (the most productive 206 g m−2 ADM). Most intercrops competed with maize and reduced its biomass productivity; however, their competitive effects were weaker than those of weeds. A strong negative correlation between maize and weed biomass was detected (max. r = −0.946; p < 0.01). Complex evaluation index (CEI) showed that the crimson clover–annual ryegrass–spring oilseed rape rotation (CC-AR-SR) was the most productive and was effective in suppressing major weeds Echinochloa crus-galli, Chenopodium album, Polygonum lapathifolium, and Cirsium arvense, less competitive with maize (CEI 4.82), and can be used as an Integrated Pest Management tool.

Background: Fish diseases are among the main challenges in the aquaculture industry. Feed additives are promising agents to control fish diseases by improving their innate immunity. Objectives: The present study was conducted to assess the effects of dietary supplementation with Cirsium arvense essential oil (CAEO) on immunological responses and disease resistance in rainbow trout, Oncorhynchus mykiss. Methods: The fish (mean weight: 31.31±0.15 g) were fed diets containing 0 (Cont), 2 (CAEO2), 4 (CAEO4) and 6 (CAEO6) mL/kg CAEO for 60 days at a daily ration of 5% of biomass (n=3), followed by an experimental infection by Yersinia ruckeri. Results: After 60 days of rearing, dietary CAEO significantly increased serum total protein, total immunoglobulin (Ig), lysozyme, alternative complement (ACH50), respiratory burst activity (measured by nitroblue tetrazolium [NBT] test), skin mucus lysozyme, protease, total Ig, and alkaline phosphatase (ALP). Dietary CAEO significantly decreased post-challenge mortality; Cont, CAEO2, CAEO4, and CAEO6 showed 100%, 58%, 68%, and 48% post-challenge mortalities, respectively. The highest total Ig, NBT, ACH50, mucus protease, and ALP, and post-challenge survival were observed in CAEO6 treatment; whereas, the highest serum total protein, mucus lysozyme, and total Ig were observed in CAEO4 and CAEO6 treatments. Serum lysozyme significantly increased in all CAEO-treated fish. Conclusion: CAEO can be used as a feed additive for the aquaculture of rainbow trout, as it improves immunity and disease resistance of the fish at a concentration of 6 mL/kg.

Weeds are plant groups that compete with cultivated crops in agricultural ecosystems, causing significant yield and quality losses. Located in the Aegean-Central Anatolian transition zone of Türkiye, Kütahya province has a rich weed flora due to its climatic and edaphic characteristics. Among the most common species in Kütahya's agricultural areas are Sinapis arvensis, Cirsium arvense, Papaver rhoeas, Avena sterilis, and Lamium amplexicaule. In this review study, the weed species commonly found in Kütahya province are examined in terms of cereals, row crops, vegetable fields, pastures, and roadsides; the ecological characteristics, reasons for distribution, and agricultural impacts of the species are evaluated in light of the literature.

The study was conducted to investigate biological efficacy and safety of new herbicide Cornegi Plus, OD (terbuthylazine 250 g/L + 2,4-D acid /2-ethylhexyl ether/ 80 g/L + clopyralid /2-ethylhexyl ether/ 40 g/L + nicosulfuron 30 g/L) for maize protection from 4 groups of weeds: annual and perennial dicotyledonous and annual and perennial monocotyledonous. Trials were conducted in 2022 and 2023 in 4 regions: in Moscow region (hybrid Voronezhsky 279 SV); in Krasnodar region (hybrid Krasnodarsky 291 AMV); in Astrakhan region (hybrid Mashuk 355 MV); in Voronezh region (hybrid Kosynier - in 2022; hybrid DKS 3730 - in 2023). Trials were carried out in accordance with «Guidelines for conducting registration trials with herbicides, 2020». The weeds were counted using the quantitative-weight method. The efficacy of herbicide was calculated relative to the untreated check. Weeds in maize without herbicide treatments in experiments ranged from 55.1 to 213.9 species/m2. The reduction of weeds by use herbicide Cornegi Plus, OD was significant in all regions and in Krasnodar region reached 100%. New herbicide Cornegi Plus, OD was more effective than standard Cornegi, SE in suppressing such annual dicotyledonous weeds as Ambrosia artemisiifolia, Matricaria perforata and Polygonum persicaria, as well as such perennial dicotyledonous weeds as Cirsium arvense and Lactuca tatarica. The highest increases in grain yield when using 1.5-2.0 l/ha of herbicide Cornegi Plus, OD were noted in 2023: at hybrid DKS 3730 in Voronezh region - 24.0-24.5 c/ha (when untreated check yield was 71.6 c/ha) and at hybrid Krasnodar 291 AMV in Krasnodar region - 21.6-22.7 c/ha (when untreated check yield was 25.3 c/ha). In the Moscow region, the increase in green mass of hybrid Voronezh 279 SV amounted to 247-277 c/ha (when untreated check yield was 150 c/ha).

To develop novel herbicides derived from natural product sources, a range of acrylopimaric acid triazole derivatives was synthesized with rosin as the starting compound. The herbicidal effectiveness of these derivatives was assessed and tested against Cyperus rotundus, Cirsium arvense, Portulaca oleracea, Lolium perenne, and Echinochloa crus-galli both pre-emergence and postemergence. Compounds 4a, 4g, 4m, and 4p exhibited inhibitory activity against C. rotundus, with compound 4m demonstrating the most effective herbicidal activity. Its pre-emergence IC50 was lower than the positive control glyphosate (6.658 mg L-1 compared to 7.556 mg L-1, respectively), and postemergence treatment resulted in a higher degree of seedling bleaching compared to the positive control treatment. Enzyme activity inhibition studies revealed that compound 4m exhibits significant inhibition against transketolase (TK), with molecular docking analysis suggesting that compound 4m can interact with TK. Furthermore, the analysis of 3D-QSAR revealed that the molecular configuration and electrostatic distribution are crucial factors for enhancing the biological activity of compounds. In conclusion, these discoveries suggest the potential of compound 4m as an herbicide and provide insights for the control of C. rotundus.

ABSTRACTPseudomonas aeruginosa, a gram‐negative bacterium present in water and soil, causes significant illnesses and chronic conditions that degrade drinking water quality. This study aimed to evaluate the antibacterial and antioxidant activities of plant extracts (Convolvulus arvensis, Chenopodium murale, Avena fatua, Cirsium arvense, and Hordeum vulgare) against P. aeruginosa. FTIR spectroscopy was used to investigate in the plant extracts, and the phytochemical compounds found in the plant extracts were analyzed using GC–MS analysis. This study evaluated the antioxidant activity of plant extracts using DPPH scavenging assays and found that ascorbic acid significantly improved the DPPH scavenging activity of C. arvensis extract compared to that of other plants. Saliva samples were collected from the patients to differentiate P. aeruginosa from other oral cavity microorganisms. Gram staining and catalase testing were performed to identify bacterial strains. Pseudomonas aeruginosa produces a positive catalase test and appears as a pink or red rod after Gram staining. This study revealed that five plant extracts have antibacterial activity against P. aeruginosa. Cirsium arvensis showed a higher zone of inhibition (72 mm). The MIC was the lowest concentration that inhibited the visible growth of a bacterium, whereas the MBC was the lowest concentration that killed 99.9% of the bacteria. A. fatua and C. murale were effective at very low concentrations, inhibiting bacterial growth at 1 μg/mL and killing bacteria at 2 μg/mL. Hordeum vulgare and C. arvense require slightly higher concentrations to effectively inhibit bacterial growth and to exert bactericidal effects. All the studied plant extracts were effective in inhibiting biofilm formation by P. aeruginosa; however, H. vulgare demonstrated the highest percentage of inhibition (99.05) at a concentration of 0.8 μg/mL. This study revealed that these plants exhibit antibacterial activity against P. aeruginosa.

Abstract It is essential to reduce pesticide and tillage use in agricultural systems, but better alternatives for controlling perennial weeds are needed. The horizontal and vertical root cutters can fragment the roots and rhizomes of perennial weeds with minimal disturbance to the soil and vegetation cover. However, there is a lack of studies on how the root cutters affect multiple perennial weed species, and their effect on soil and nutrient losses. To fill this gap, three multi-year experiments in plowed systems were conducted in Norway and Sweden to study whether the roots cutters can control multiple perennial weed species as effectively as more intensive tillage methods (Experiments 1-2), without increasing soil and nutrient losses (Experiment 3). Overall, the more intensive tillage methods tested (rotary tiller, disc harrow, stubble harrow) did not provide significantly better perennial weed control than the horizontal root cutter. In Experiment 1, the horizontal root cutter reduced Sonchus arvensis and Elymus repens shoot biomass by 52% and 80%, respectively, compared to an untreated control. In Experiment 2, the horizontal root cutter reduced Cirsium arvense shoot numbers by 71% compared to the untreated control but failed to reduce E. repens . Horizontal root cutter treatment depth (7 vs. 15 cm) did not affect control efficacy. The horizontal root cutter treatment did not increase soil, water or nutrient losses compared to the untreated control, and resulted in 60% less soil and 52% less phosphorous losses than disc harrowing. Treatments with the vertical root cutter had 40% less E. repens and 22% less S. arvensis shoot biomass than treatments without the vertical root cutter. This manuscript is the first to show the true potential of the root cutters in plowed systems in northern Europe and their ability to control of multiple perennial weed species with low risk of soil and nutrient losses.

The international crop seed trade is a major pathway for the unintentional introduction of non-native invasive plant species and herbicide-resistant weeds, posing biosecurity threats to agriculture and ecosystems. However, published studies examining weed contaminants in crop seed remain scarce. To address this, we analysed Canadian Food Inspection Agency (CFIA) monitoring data for 2,080 randomly sampled crop seed lots imported from the United States of America (USA) between 2007 and 2019. Both nations are major players in the global seed trade, making them key biosecurity case studies. We reported 262 contaminant species: 70% were introduced in Canada, 23% were native, and 7% had not been previously recorded (absent) in Canada. General weeds (not also imported as crops) comprised 63% of contaminant species; the remaining species were classified as seed of another crop. CFIA-classified noxious weeds (Classes 1–5) made up 12% of the contaminant species. Most contaminants were associated with only one or two crop species. There was a decline in general and noxious weeds, and noxious weeds were reported significantly less than non-noxious weeds over the study period. Entry-prohibited species (Class 1) were rare, limited to four records of Cuscuta spp. We identified 14 general weed species currently absent from Canada, notably the frequently reported Trifolium vesiculosum, along with Galium parisiense, Torilis nodosa, and Trifolium hirtum, all established in climatically similar regions of the USA, as well as Bromus catharticus and Euphorbia aleppica, identified as environmental and agricultural threats. Eight additional species, such as Apera spica-venti, currently limited to one Canadian province, pose a potential domestic spread risk. Reported Class 2 CFIA noxious weeds, including Cirsium arvense, Convolvulus arvensis, and Elymus repens, are of concern as their ecological range is not fully realised in Canada. Chenopodium album was the most widespread general weed detected across crop species. Contaminants with a known history of herbicide resistance in the USA but not in Canada increased significantly over time (e.g., Sorghum halepense, Poa annua), while those resistant in one Canadian province (Bromus tectorum) risk further spread in Canada. The introduction of new resistance is of concern when a contaminant species is reported in a crop type in Canada and documented as herbicide-resistant in the same crop type in the USA (Poa annua in forage and turf seed lots). Regulatory concerns include importing crops that are also classified as noxious or problematic weeds (Bromus tectorum, Poa annua), permitting contaminants absent from Canada in seed lots, and the dual classification of species that are native but also entry-prohibited (Cuscuta campestris). Our study highlights that expanded global seed trade necessitates ongoing seed lot monitoring, risk assessment, and adaptive regulations to help safeguard agriculture and biodiversity without hindering trade.

ABSTRACT Aim Land use intensification has resulted in extensive habitat degradation, negatively impacting many ecosystem services. Restoring disturbed lands to their former state is crucial for preserving biodiversity and ecosystem health. Although the use of native species to revegetate disturbed ecosystems continues to gain momentum, knowledge about native species management for field‐based revegetation remains limited. Location Disturbed grassland, Alberta, Canada. Methods A study was conducted to examine the impact of native seed mix richness (mix I: 6 grasses, mix II: 10 grasses, mix III: 6 grasses +10 forbs, mix IV: 10 grasses +10 forbs, and mix V: 6 grasses +10 transplanted forbs), seeding season (fall, spring), and first‐year mowing (mowed, unmowed) on plant community development over 8 years. Results After 8 years, seed mix richness, seeding season, and mowing had little effect on cover, richness, or diversity; however, seed mixes influenced seeded and transplanted forbs. The sites were mostly dominated by non‐native species. Plant community composition was not affected by seed mix richness, season, and mowing. Poa pratensis , Taraxacum officinale , Cirsium arvense, and Trifolium pretense were the most dominant species and accounted for 53% of the dissimilarity. Conclusions The presence of seven seeded grass and nine seeded forb species indicates that most seeded species survived, although appropriate management of non‐native species is needed for their establishment. This study suggests using a richer seed mix does not guarantee a higher species richness in plant communities.

ABSTRACTInsect–flower relationships are among the most important ecological interactions occurring in the terrestrial ecosystem. In urban areas, such interactions are often disturbed or altered. However, few studies report floral affinities of butterflies in Europe, and our understanding of flower utilisation by butterflies in urban habitats is limited. Our study included long‐term (2017–2022), qualitative observations and quantitative analyses of flower visits performed in 2021 and 2022 on five urban wastelands located in Łódź (Central Poland). We have recorded observations of 39 butterfly species on 81 species of plants (representing 19 families and 16 orders of plants). The majority of butterfly species were associated with many species of plants. We did not record tight associations with the colour of flower or the depth of flower, although in general, butterflies were observed on pink (21 species of plants), yellow (20 species of plants), white (17 species of plants) and violet (13 species of plants) flowers, while they were not recorded on orange, blue or red flowers. The most commonly visited flowering plants represented Asteraceae, Fabaceae and Lamiaceae. The highest number of butterflies was recorded on Jasione montana (22 species of butterflies), Cirsium arvense (19 species of butterflies), Berteroa incana (22 species of butterflies), Trifolium pratense (22 species of butterflies) and Origanum vulgare (21 species of butterflies). The highest number of individuals was observed on Centaurea stoebe, Senecio jacobaea, Cirsium arvense and Echium vulgare. Our study showed that urban wastelands provide flower resources for butterflies and should be included in the management practices of large cities.

This study, which began in the 2013/2014 agricultural year, aimed to assess the suitability of two soil tillage systems for wheat cultivation: conventional soil tillage (CS), which involved moldboard plowing to a depth of 28 cm followed by a single pass with a rotary harrow to prepare the seedbed, and no-tillage (NT). It also sought to analyze the impacts of these systems on weed infestation levels and, consequently, on yield. A moderate level of fertilization was applied. The experimental field was established with a three-year crop rotation system: soybean–winter wheat–maize. The total number of weed species was 30 in CS, the representative species being Xanthium strumarium, and in NT there were 29 species, with Xanthium strumarium, Cirsium arvense, Bromus tectorum, and Agropyron repens predominating. There was an increase in the number of perennials (dicots and monocots). The total dry matter of weeds was 35.4 t ha−1 in CS and 38.8 t ha−1 in NT. After 11 agricultural years, it was found that there were no significant differences between the two soil tillage systems in terms of wheat yield (6.55 t ha−1 in CS and 6.46 t ha−1 in NT). The uneven rainfall negatively affected wheat growth and favored the spread of weeds, especially dicotyledonous ones.

Similarly to conventional field crops, weeds often pose significant problems in the cultivation of medicinal plants. To date, no comprehensive documentation exists regarding weed infestation levels in these crops in Serbia. The objective of this study was to provide a valuable foundation for developing effective, site-specific weed management strategies in medicinal crop production. Weeds in five medicinal crops (lemon balm, fennel, peppermint, ribwort plantain, German chamomile), were surveyed based on the agro-phytosociological method between 2019 and 2024, and across 59 plots. A total of 109 weed species were recorded, belonging to 29 families and 88 genera. Among them, 75 were annuals and 34 perennials, including 93 broadleaved species, 10 grasses, and one parasitic species. All surveyed plots were heavily infested with perennial weeds such as Elymus repens, Cirsium arvense, Convolvulus arvensis, Lepidium draba, Rumex crispus, Sorghum halepense, Taraxacum officinale, etc. Also, several annual species were found in high abundance and frequency, including Amaranthus retroflexus, Chenopodium album, Galium aparine, Lactuca serriola, Lamium amplexicaule, L. purpureum, Papaver rhoeas, Stellaria media, Veronica hederifolia, V. persica, etc. The most important ecological factors influencing the composition of weed vegetation in investigated medicinal crops were temperature and light for fennel and peppermint plots, soil reaction for lemon balm and ribwort plantain plots, and nutrient content for German chamomile plots. A perspective for exploitation of these results is the development of effective weed control programs tailored to this specific cropping system. Weed control strategies should consider such information, targeting the control of the most frequent, abundant, and dominant species existing in a crops or locality.

Rhipicephalus microplus, a tick species, causes significant economic losses in livestock and presents control challenges due to the emergence of resistance to conventional acaricides. This underscores the urgent need for effective and eco-friendly alternatives. This study evaluates the acaricidal potential of Cirsium arvense using adult immersion and larval packet tests. In silico molecular docking techniques were employed to identify biologically active compounds within C. arvense. Using Chem-Draw Ultra software (version 12.0.2, 2010), we illustrated 25 compounds derived from the plant, which were subsequently tested as ligands in docking experiments against Subolesin. Among the tested compounds, Apigenin 7-O-glucosideand Pectolinarigenin 7-glucoside exhibited significant inhibitory effects on Subolesin, with docking scores of -6.6 and - 6.3kcal/mol, respectively. In contact bioassays using Cirsium arvense extract, various concentrations (2.5, 5, 10, 20, and 40mg/mL) were evaluated. The results indicated an LC50 of 2.907mg/mL and an LC90 of 47.725mg/mL after 24h of exposure. Notably, at the highest concentration of 40mg/mL, the extract significantly reduced egg-laying activity in adult female ticks, yielding an oviposition index of 0.09 ± 0.02, which corresponds to a 75.68 ± 0.44% reduction in reproductive capacity. Additionally, larval mortality reached 88.33 ± 2.90%, indicating that higher concentrations not only increased larval mortality but also substantially decreased the reproductive capacity of the ticks. These findings suggest that bioactive components from Cirsium arvense show promise as candidates for the control of R. microplus. Further research is warranted to evaluate their efficacy as alternative or complementary strategies to synthetic acaricides.

Abstract Weed harmfulness is linked to the plant functional traits. The two widely dispersed weeds, Cirsium arvense and Artemisia vulgaris, are similar in taxonomic and ecological terms, but they differ by abundance in agroecosystems. We studied 25 leaf, mesophyll, cell and chloroplast traits of these species in two habitats: ‘ruderal’ (roadside meadow) and ‘agricultural’ (ploughed field). Independently of habitat, C. arvense had higher leaf thickness (LT) and leaf mass per area, but lower leaf density (LD) than A. vulgaris . The mesophyll cell volume ( V cell ) was threefold larger, with twice the chloroplast number per cell (Chl) in C. arvense compared to A. vulgaris . In the ruderal habitat, there was no difference between species in net assimilation rate ( A max ) and integrated mesophyll traits—the total mesophyll and chloroplast surface area per leaf area unit ( A mes / A , A chl / A ). In the agricultural habitat, C. arvense exhibited a threefold increase in A max , accompanied by a twofold rise in A mes / A and A chl / A , exceeding the common values reported for mesophytic perennial non‐weeds. A. vulgaris showed no change in A mes / A and A chl / A , with A max increasing by only 30%. Common features of both weeds in agricultural conditions were an increased up to 60% contribution of spongy to mesophyll traits, enhanced photosynthetic activity of a chloroplast and elevated rate of CO 2 transfer through cell and chloroplast surfaces. We conclude that large V cell related to high LT and low LD, as well as the high spongy proportion and plasticity in A mes / A and A chl / A contribute to the success of C. arvense in agricultural environments.

Cirsium arvense is among the most pervasive and resilient weed species, playing a critical role in the epidemiology of phytopathogenic fungi within agroecosystems. The present study aimed to characterize fungal pathogens associated with C. arvense populations growing adjacent to cereal and legume crop fields in the North Kazakhstan region. Fungal isolates were obtained from symptomatic plant tissues, including leaves, stems, and inflorescences. Pure cultures were established through cultivation on nutrient media under controlled conditions. Molecular identification was conducted using ribosomal DNA internal transcribed spacer (ITS) region sequencing, and species-level classification was achieved by comparison with GenBank entries via BLAST analysis. The dominant fungal taxa identified were Alternaria alternata and Fusarium tricinctum. To elucidate the evolutionary placement of the isolates, a phylogenetic tree was constructed using the Neighbor-Joining method implemented in MEGA 11 software. The findings indicate that C. arvense functions as a natural reservoir for economically important phytopathogenic fungi, underscoring its epidemiological relevance and the need for integrated weed and disease management strategies in agricultural systems.

One of the positive roles of weeds may be their potential use as medicinal plants. The aim of this article is to evaluate the occurrence and distribution of weeds with pharmaceutically important active substances on arable land in the Czech Republic in organic farming. In 2006–2018, a phytocoenological survey was performed on selected organic farms in different production areas representing various climate and soil conditions and in different crops. A total of 223 species were found throughout the survey and of those, 56 species were identified to have a pharmaceutical significance. The effect of different production area and crops on the occurrence of these species was found statistically significant; however, most of the plants were not strongly associated with a particular region or crop. Among the species that were both frequent and with high mean cover are Cirsium arvense, Polygonum aviculare, Capsella bursa-pastoris, Stellaria media, Galium aparine, Elytrigia repens, Convolvulus arvensis, Fumaria officinalis, Centaurea cyanus, Descurainia sophia and Equisetum arvense . Recognizing possible benefits of ecosystem services provided by arable weeds and finding opportunities for organic farmers to have new seasonal markets may help improve sustainability of small farming operations.

Cirsium arvense, also known as Canada or creeping thistle, is a noxious perennial weed in North America that severely impacts native and agriculturally significant crops. Recent research has been focusing on the use of the rust Puccinia suaveolens as a biological control agent. In 2025, Canada thistles in a growth chamber on Centennial Campus of North Carolina State University (35.77405°N, 78.67579°W) became infected with powdery mildew. Leaves were completely covered with white mycelial growth. Morphologically, mycelium was amphigenous, effuse; hyphae flexuous, hyaline, septate, 4-6 µm wide; hyphal appressoria indistinct to nipple shaped, 5-7 µm diam.; conidiophores arising from the upper surface of the mother cell, straight, unbranched; foot-cells subcylindrical, (50-)78-94(-112) × 9-11 µm, followed by 1-3 shorter cells after foot cell; conidia hyaline, cylindrical-doliiform, lacking fibrosin bodies, (29-)33-35(-38) × 14-16(-20) µm, length/width ratio 2-2.3; germ tubes ± terminal, 22-32(-73) µm long, conidial appressoria club shaped, Euoidium type; chasmothecia were not observed. The anamorph of the specimen identified in this study was shown to be morphologically identical to Golovinomyces ambrosiae and had significant differences from the closely related G. latisporus in conidial shape and size as well as in the shape of the conidial appressoria. The two species can be differentiated in that G. ambrosiae has narrower and longer cylindrical-doliiform conidia with a length/width ratio that can be >2 versus G. latisporus with shorter and broad ellipsoid-ovoid, doliiform conidia with a length/ratio < 2 on average (1.3-1.9). Additionally, the conidial germ tubes of G. ambrosiae were short with typical Euoidium type, swollen tips while G. latisporus exhibits longer germ tubes often of the longitubus type (Qiu et al. 2020). Golovinomyces montagnei, which is a common pathogen for this host in Europe, has wider and longer conidia; (25-)30-45 × 15-23 μm (Braun and Cook 2012). We sequenced the ITS (GenBank Number: PV581748), IGS (PV584301), GAPDH (PV584324), GS (PV584325), and RPB2 (PV584332) regions with the following primer pairs: PM10 (Bradshaw and Tobin 2020) /PM2 (Cunnington et al. 2003), IGS-12a/NS1R (Carbone and Kohn, 1999), PMGAPDH1/PMGAPDH3R, GSPM2/GSPM3R, and PMRpb2_4/PMRpb2_6 (Bradshaw et al. 2022a). All regions sequenced aligned 100% with other G. ambrosiae specimens including FH00941245 (ON073878, ON361194, ON075631, ON119167, ON075691) and FH00941246 (ON073842, ON361187, ON075629, ON075689, ON119163). The specimen was deposited in the Larry F. Grand Mycological Herbarium (Voucher Number: NCSLG 25310). We confirmed pathogenicity using two uninfected Canada thistle plants. One plant was inoculated by touching diseased leaves to wet healthy leaves and then kept in the same growth chamber as the infected plants. The other plant was not inoculated and placed in a separate growth chamber as a control. Ten days after inoculation, typical powdery mildew symptoms and signs were observed. Powdery mildew was also observed spreading to multiple other Canada thistle plants in the growth chamber that held the inoculated plant. No symptoms were observed on the non-inoculated control plant. Golovinomyces montagnei and G. depressus have been reported to infect C. arvense from Europe (Bradshaw et al. 2024). Multiple reports have identified powdery mildew on C. arvense from Idaho, Washington, and Oregon as Erysiphe cichoracearum or Golovinomyces cichoracearum, but these names have been used broadly for a range of powdery mildew species (Newcombe and Nischwitz 2004; Dungan and Glawe 2007; Bradshaw et al. 2022b); both reports could have been referring to G. ambrosiae, G. montagnei or G. depressus. However, based on the present study, it is highly likely that they were referring to G. ambrosiae. Interestingly, from personal observations, the powdery mildew tended to infect the plant most heavily when the rust, P. suaveolens, was also present. This information is important for the agriculture industry where C. arvense is a major problem.

Abstract Cirsium arvense is a troublesome weed and biocontrol is warranted. Currently, fungal biocontrol agents perform inconsistently, and endophytes may be contributing to this. This research investigates the endophytic communities in leaf, stem, and root tissue of C. arvense in the Lincoln area of New Zealand and their seasonal dynamics. Samples were collected in spring, summer, and autumn. They were cultured and sorted by morphotype before identification to genus level was determined with Sanger sequencing. Data was analysed with the software R and the diversity and community composition of endophytic communities were determined. From this study it was evident that endophytic diversity in leaf tissue increases over the growing season from a true Shannon diversity of 3.4 in November 2021 to 7.5 in April 2022. The leaf communities were also highly variable in their composition with Alternaria, Cladosporium, Epicoccum, and Stemphylium increasing over the season and Aureobasidium decreasing. In roots, endophytic diversity was lowest in February, which may be related to the higher temperatures in summer. The composition of these communities started to change in autumn with Ceratobasidium, Cladosporium, Trichoderma, and Aspergillus increasing in abundance. Diversity and composition of fungal communities in stems remained consistent across seasons. This may indicate that applying a fungal biocontrol agent to stems may be the best approach to control this weed. This study elucidated seasonal dynamics of endophytic communities within C. arvense tissues and highlighted differences between tissues which increases our understanding of these communities and may help to develop more effective biocontrol of this plant.

Understanding the carbohydrate dynamics of sprouting Cirsium arvense (L.) Scop. and Sonchus arvensis L. ramets can assist in optimizing perennial weed management. However, detailed knowledge about general reserve dynamics, minimum values in reserves (compensation point) and different reserve determination methods remains sparse. We present novel insights into reserve dynamics, which are especially lacking for S. arvensis. We uniquely compare root weight changes as a proxy for carbohydrates with direct carbohydrate concentration measurements using high-performance liquid chromatography (HPLC). In a greenhouse study, ramets of two sizes (20 and 10 cm) were planted in pots. Subsequent creeping roots of sprouted plants were destructively harvested and analyzed for carbohydrates 12 times between planting and flowering. Efficiency in storing carbohydrates and the replenishing rate of root weight and carbohydrates was much higher in S. arvensis than in C. arvense. Thus, our study urges to evaluate perennial weed species individually when investigating root reserves. Determining root reserves by either using root weight changes as a proxy for carbohydrates or directly measuring carbohydrate concentrations by HPLC differed in the minimum values of reserves referred to as compensation points. For both species, these minimum values occurred earlier based on root weight than based on carbohydrate concentrations. Cutting ramets into 20 or 10 cm sizes did not significantly affect carbohydrate concentration or root weight changes for both species. We conclude that any practical applications targeting perennial weeds by fragmenting roots into small ramets through belowground mechanical control must be evaluated for trade-offs in soil structure, soil erosion, and energy consumption.

Hazelnut (Corylus avellana L.) plays a crucial role in the agricultural landscape of Oregon's Willamette Valley, where weed and sucker management are labor-intensive and time-consuming endeavors. Current control strategies are either costly but effective, ineffective, or environmentally unfriendly. Tiafenacil, a relatively new herbicide, could be an effective solution. Field studies were conducted in commercial hazelnut orchards across the Willamette Valley to evaluate the efficacy of tiafenacil for weed and hazelnut sucker control. The results confirmed that tiafenacil applied three times per season up to 200 g ai ha-1 did not injure tree trunk or canopy and had no adverse effects on growth parameters, chlorophyll fluorescence, or yield. Tiafenacil at 50 g ai ha-1 outperformed carfentrazone 35 g ai ha-1 in controlling prostrate knotweed (Polygonum aviculare L.), wild carrot (Daucus carota L.), and Canada thistle (Cirsium arvense L. Scop). However, tiafenacil up to 50 g ai ha-1 was less effective than glufosinate 1,050 g ai ha-1 for weed control. Tiafenacil at 50 g ai ha-1 effectively managed suckers comparable to manual removal and with superior efficacy to carfentrazone. Tiafenacil at 50 g ai ha-1 combined with glufosinate or 2,4-D 1,060 g ai ha-1 improved sucker and weed control compared with tiafenacil alone at the same rate, suggesting that its efficacy is enhanced in mixtures. Importantly, tiafenacil exhibited excellent compatibility with 2,4-D and glufosinate, making it a practical option for improving weed and sucker control strategies. For growers, incorporating tiafenacil into their management programs—either as a standalone treatment or in combination with glufosinate or 2,4-D—offers an effective alternative to manual sucker removal while maintaining strong weed control. These findings support tiafenacil as a valuable addition to hazelnut management programs, especially when used in combination with other herbicides for enhanced sucker and weed control without compromising tree health. While no antagonistic effects were observed when tiafenacil was mixed with glufosinate or 2,4-D, further research is necessary to explore potential interactions with other herbicides. Additionally, the economic viability of herbicide combinations should be evaluated before broad adoption.