Search Results (99)

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. Full article

Sorghum halepense (L.) Pers. (common name Johnson grass) is a perennial invasive weed that causes great harm worldwide, and its allelopathy has been demonstrated in a series of experiments. The present study offers new insights into its organ-specific phytochemical profiles using state-of-the-art metabolomic technology and explores the effects of a methanol extract of S. halepense rhizomes (ShER) and its major bioactive compounds (p-hydroxybenzoic acid and chlorogenic acid) on three noxious weed species. The phytotoxic effects of ShER are reflected through the inhibition of seed germination and reduced seedling growth, which are accompanied by changes in the antioxidant system of seedlings. Phytotoxicity is species specific and concentration dependent, and it is more pronounced against Chenopodiastrum murale (L.) S. Fuentes, Uotila & Borsch and Datura stramonium L. than highly tolerant Amaranthus retroflexus L. Catalase (CAT) is most likely the major mediator in the removal of reactive oxygen species, which are generated during germination and early seedling growth of Ch. murale exposed to ShER. The results of the present study imply the high potential of ShER in the management of amaranthaceous and solanaceous weeds, such as Ch. murale and D. stramonium, respectively. The present study offers an environmentally friendly solution for the biological control of weeds belonging to the families Amaranthaceae and Solanaceae. Also, the results of this research highlight the possibility of effective management of S. halepense by using it as a feedstock for bioherbicide production. Full article

The United States leads in corn production and consumption in the world with an estimated USD 50 billion per year. There is a pressing need for the development of novel and efficient techniques aimed at enhancing the identification and eradication of weeds in a manner that is both environmentally sustainable and economically advantageous. Weed classification for autonomous agricultural robots is a challenging task for a single-camera-based system due to noise, vibration, and occlusion. To address this issue, we present a multi-camera-based system with decision-level sensor fusion to improve the limitations of a single-camera-based system in this paper. This study involves the utilization of a convolutional neural network (CNN) that was pre-trained on the ImageNet dataset. The CNN subsequently underwent re-training using a limited weed dataset to facilitate the classification of three distinct weed species: Xanthium strumarium (Common Cocklebur), Amaranthus retroflexus (Redroot Pigweed), and Ambrosia trifida (Giant Ragweed). These weed species are frequently encountered within corn fields. The test results showed that the re-trained VGG16 with a transfer-learning-based classifier exhibited acceptable accuracy (99% training, 97% validation, 94% testing accuracy) and inference time for weed classification from the video feed was suitable for real-time implementation. But the accuracy of CNN-based classification from video feed from a single camera was found to deteriorate due to noise, vibration, and partial occlusion of weeds. Test results from a single-camera video feed show that weed classification accuracy is not always accurate for the spray system of an agricultural robot (AgBot). To improve the accuracy of the weed classification system and to overcome the shortcomings of single-sensor-based classification from CNN, an improved Dempster–Shafer (DS)-based decision-level multi-sensor fusion algorithm was developed and implemented. The proposed algorithm offers improvement on the CNN-based weed classification when the weed is partially occluded. This algorithm can also detect if a sensor is faulty within an array of sensors and improves the overall classification accuracy by penalizing the evidence from a faulty sensor. Overall, the proposed fusion algorithm showed robust results in challenging scenarios, overcoming the limitations of a single-sensor-based system. Full article

Plant species harbor diverse rhizospheric bacteria within their resilient root zones, serving as a valuable reservoir of bioactive microorganisms with strong potential for natural antifungal and plant growth-promoting applications. This study aimed to investigate the antagonistic potential of Bacillus zhangzhouensis, isolated from Zygophyllum oxianum in the Aral Sea region, Uzbekistan, against the fungal pathogen Cytospora mali. Due to its strong antifungal activity, B. zhangzhouensis was selected for bioactive compound profiling. Methanolic extracts were fractionated via silica and Sephadex gel chromatography, followed by antifungal screening using the agar diffusion method. A highly active fraction (dichloromethane/methanol, 9:1) underwent further purification, yielding twelve antifungal sub-fractions. Mass spectrometry analysis across positive and negative ion modes identified 2475 metabolites, with polar solvents—particularly methanol—enhancing compound recovery. Refinement using Bacillus-specific references identified six known antibiotics. Four pure compounds were isolated and structurally characterized using NMR: oleanolic acid, ursolic acid, cyclo-(Pro-Ser), and uracil. Their growth regulatory activity was assessed on Amaranthus retroflexus, Nicotiana benthamiana, triticale, and Triticum aestivum at concentrations of 5, 20, 100, and 500 mg L−1. All compounds negatively affected root growth in a concentration-dependent manner, especially in monocots. Interestingly, some treatments enhanced stem growth, particularly in N. benthamiana. These findings indicate that B. zhangzhouensis produces diverse bioactive compounds with dual antifungal and plant growth-modulatory effects, highlighting its potential as a biocontrol agent and a source of natural bioactive compounds. Full article

Weeds compete with crops for resources, posing multiple negative impacts for agricultural production systems and triggering degradation of ecosystem services (e.g., alterations in the soil microbial community structure). Under the guidance of green plant protection, the development of efficient biocontrol strains with environmentally friendly characteristics has become a crucial research direction for sustainable agriculture. This study aimed to develop a fungal bioherbicide by isolating and purifying a pathogenic fungal strain (JZ-5) from infected redroot pigweed (Amaranthus retroflexus L.). The strain exhibited pathogenicity rates ranging from 23.46% to 86.25% against six weed species, with the most pronounced control efficacy observed against henbit deadnettle (Lamium amplexicaule L.), achieving a pathogenicity rate of 86.25%. Through comprehensive characterization of cultural features, morphological observations, and molecular biological identification, the strain was taxonomically classified as Fusarium oxysporum. Scanning electron microscopy revealed that seven days post-inoculation, F. oxysporum JZ-5 formed dense mycelial networks on the leaf surfaces of cluster mallow (Malva verticillata L.), causing severe tissue damage. Safety assessments demonstrated that the spore suspension (10⁴ spores/mL) had no adverse effects on three crops: hulless barley (Hordeum vulgare var. coeleste L.), wheat (Triticum aestivum L.), and potato (Solanum tuberosum L.). These findings suggest that F. oxysporum strain JZ-5 warrants further investigation as a potential bioherbicide for controlling three problematic weed species—Chenopodium album L. (common lambsquarters), Elsholtzia densa Benth. (dense-flowered elsholtzia), and Lamium amplexicaule L. (henbit deadnettle)—in cultivated fields of hulless barley (Hordeum vulgare var. coeleste L.), wheat (Triticum aestivum L.), and potato (Solanum tuberosum L.). This discovery provides valuable fungal resources for ecologically sustainable weed management strategies, contributing significantly to the advancement of sustainable agricultural practices. Full article

Amaranthus retroflexus L. is widely regarded as one of the world’s most invasive weeds, often linked to significant agricultural losses due to its resilience and herbicide resistance. However, unlike other amaranth species already recognized for their health benefits, A. retroflexus remains largely overlooked as a potential nutritional and pharmacological resource. This study investigates whether this abundantly growing plant could be repurposed as sustainable food. We focused on three main questions: Can weed be transformed into a food source? Does A. retroflexus offer comparable nutritional value as its relatives? And how can it be harvested safely for human use? Mineral content, total antioxidant capacity, and polyphenol content were analyzed across different plant parts. Results revealed high levels of essential minerals, antioxidants, and other bioactive compounds, suggesting strong potential as a nutrient-dense food. However, traces of heavy metals—such as lead, cadmium, and arsenic—were detected in some samples, emphasizing the need for controlled cultivation. Overall, the findings support the safe and sustainable valorization of A. retroflexus in food and pharmaceutical applications. Full article

The use of Artemisia species’ plant extracts and essential oils, which are rich in bioactive compounds (allelochemicals), could support weed management. This study focused on the chemical analysis and evaluation of the allelopathic potential of plant extracts (PEs) and essential oils (EOs) of Artemisia absinthium and A. vulgaris on the germination and early seedling growth of weeds (Amaranthus retroflexus and Setaria viridis) in vitro. The plant extract from A. vulgaris showed higher antioxidant activity (IC₅₀ = 0.171 ± 0.01 mg/mL) and phenolic content than that from A. absinthium (IC₅₀ = 0.263 ± 0.01 mg/mL). Chlorogenic acid was the most abundant phenol in both extracts. However, A. absinthium contained a higher amount (1.694 ± 0.081 mg/g) and exhibited a stronger inhibitory effect on the germination of A. retroflexus (EC₅₀ = 0.54 ± 0.02%) and S. viridis (EC₅₀ = 1.51 ± 0.07%) compared to A. vulgaris. The dominant components of A. absinthium essential oil were β-thujone (18.9%), cis-ocimene epoxide (7.88%), and bicyclogermacrene (7.04%), while the main constituents of A. vulgaris essential oil included gurjunene (10.41%), cis-crysanthenyl acetate (7.17%), and γ-humulene (6.67%). The lowest EC₅₀ values for A. absinthium essential oil regarding seed germination and seedling length were estimated for S. viridis (0.28 ± 0.48% and 0.03 ± 0.00%, respectively), whereas A. retroflexus was the most sensitive to A. vulgaris essential oil (0.11 ± 0.04% and 0.02 ± 0.00%, respectively). All tested extracts showed allelopathic potential; however, the results indicate that the essential oils had a stronger inhibitory effect than the plant extracts. Full article

Weeds are a significant challenge to global agricultural production, significantly impacting crop yields. The evolution of resistance to synthetic herbicides, along with their adverse environmental effects, underscores the need for alternative control strategies. This study reports the production, purification, and evaluation of the herbicidal activity of a metabolite produced by Phoma dimorpha (NRRL 43879) via submerged fermentation. To the best of our knowledge, this is the first report on the evaluation of the herbicidal potential of metabolites isolated from the cultivation of this microorganism. Metabolites extracted with ethyl acetate were fractionated into three fractions, with only one showing herbicidal activity. Fraction 1 controlled 96.25% of Amaranthus retroflexus plants in a leaf puncture bioassay at 2 mg mL⁻¹ and 96.67% when applied to the aerial parts at 600 µg mL⁻¹ with 0.1% Tween 80. The purified compound was also tested on Raphanus sativus seed germination, reducing rates by 80% and 26% at 24.5 mg mL⁻¹ and 12.25 mg mL⁻¹, respectively. Seedling length decreased by 80% and 31% under the same treatments. These results highlight the potential of this metabolite as a sustainable alternative for weed management, supporting the development of novel bioherbicides. Full article

Utilizing nanotechnology for weed management offers a sustainable alternative to synthetic herbicides. This study evaluated the effectiveness of sunn hemp extract (SH), Fe₃O₄ nanoparticles (NPs), and Fe₃O₄/sunn hemp NPs in inhibiting the germination of redroot pigweed (Amaranthus retroflexus L.), wild mustard (Sinapis arvensis L.), and lamb’s quarters (Chenopodium album L.) weeds. The structural characteristics of the NPs were analyzed using Scanning electron microscopy (SEM), Scanning X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Vibrating sample magnetometer (VSM), Brunner–Emmet–Teller (BET), and Fourier-transform infrared spectroscopy (FTIR). The optimal Fe₃O₄ NP concentration for reducing seed germination ranged from 3000 to 3100 mg L⁻¹. Higher concentrations of SH extract (100, 150, and 200 g L⁻¹) effectively inhibited weed seed germination with A. retroflexus displaying the highest sensitivity. The maximal effective concentration (NOEC_max) for Fe₃O₄/sunn hemp NPs was 10 g L⁻¹ for S. arvensis, 150 g L⁻¹ for A. retroflexus, and 200 g L⁻¹ for C. album. Fe₃O₄/sunn hemp NPs led to a reduction in 1/D₅₀ and an increase in EEC₅₀, indicating a rise in sensitivity to Fe₃O₄ NPs, particularly in S. arvensis. Variations in species responses to SH, Fe₃O₄ NPs, and Fe₃O₄/sunn hemp NPs are likely influenced by genetic, physiological, and ecological factors. Overall, the findings suggest that utilizing Fe₃O₄/sunn hemp NPs offers an effective strategy for sustainable weed management. Full article

6-Aryl-2-picolinic acid herbicides are an important subclass of auxin herbicides, characterized by their good absorption and conductivity, broad weed control spectrum, and excellent herbicidal activity against some resistant weeds. Based on previous studies from our group and the distinct characteristics of physico-chemical properties and biological activities of active skeleton structure containing fluorine atoms, this paper introduces the design and synthesis of 41 novel 4-amino-6-(5-aryl-substituted-1-pyrazolyl)-3-chloro-5-fluoro-2-picolinic acid compounds. The test of inhibiting A. thaliana roots growth showed that most of the S-series compounds exhibited superior inhibitory effects compared to picloram, with six compounds demonstrated even better inhibitory capability than the new herbicidal molecule florpyrauxifen. For example, compound S202, at a concentration of 0.5 µmol/L, exhibited a 78.4% inhibition of A. thaliana root growth, whereas florpyrauxifen showed only a 33.8% inhibition. Root growth inhibition tests on weeds showed that 28 compounds, at a concentration of 250 µM, demonstrated a greater than 80% inhibition of Brassica napus (BN) root growth. Post-emergence herbicidal activity tests showed that most compounds exhibited good inhibitory effects on broadleaf weeds, with 10 compounds achieving a 100% inhibition of the growth of Amaranthus retroflexus L (AL). These results demonstrate that some of the 4-amino-6-(5-aryl-substituted-1-pyrazolyl)-3-chloro-5-fluoro-2-picolinic acid compounds could be used as potential lead structures in the discovery of novel synthetic auxin herbicides. Full article

Amaranthus, a genus in Amaranthaceae, is divided into three subgenera—Amaranthus, Acnida, and Albersia—and contains approximately 70 to 80 species. Understanding its phylogenetic relationships is essential for species classification, genetic diversity assessment, and evolutionary studies. This knowledge is vital for improving Amaranthus utilization in crop improvement and managing the ecological impacts of invasive weeds. In this study, we analyzed the chloroplast genomes of 27 Amaranthus species across all three subgenera to characterize their genomic features and construct a comprehensive phylogenetic tree. Our aim was to elucidate the phylogenetic relationships within the genus and evaluate interspecific affinities among the subgenera. We also addressed the taxonomic ambiguity surrounding A. bouchonii and A. powellii to determine their distinct species within the genus. Chloroplast genome sizes ranged from 149,949 to 150,818 bp, with GC content varying between 36.52% and 36.63%. Comparative structural analyses confirmed highly conserved quadripartite structures, gene content, and organization, comprising 87 protein-coding genes, 37 tRNAs, and 8 rRNAs. Repeat and codon usage analyses revealed conserved repeat patterns and a preference for codons ending in A or U. Selection pressure analysis indicated a predominantly purifying selection, with matK showing signs of positive selection, particularly in A. spinosus. Phylogenetic analysis of 80 protein-coding genes confirmed the monophyly of subgenus Amaranthus but found Alberisa and Acnida to be paraphyletic. Despite their morphological similarity, A. bouchonii and A. powellii were placed in separate clades within subgenus Amaranthus, with A. bouchonii clustering with A. retroflexus, and A. powellii aligning with the A. hybridus complex. Additionally, we identified 16 variable regions as potential molecular markers for species identification. Our study provides the most comprehensive Amaranthus chloroplast genome dataset to date, offering new insights into its evolutionary relationships and valuable genomic resources for taxonomy, germplasm management, and invasive risk assessment. Full article

Amaranthus retroflexus is a highly invasive annual broadleaf weed in soybean fields, significantly reducing soybean yield and quality. Diphenyl ether herbicides, particularly fomesafen, are extensively applied to control A. retroflexus. Fomesafen resistance of A. retroflexus is emerging in Northeast China, and rapid resistance detection is urgent for managing these resistant weeds. An Arg-128-Gly mutation in the ppo2 gene of A. retroflexus has been shown to confer fomesafen resistance. In current study, we developed a rapid detection method based on Kompetitive Allele-Specific PCR (KASP) technology to detect the Arg-128-Gly mutation in the ppo2 gene of A. retroflexus. Initially, we developed this KASP detection method using cDNA as the template; however, the entire process requires significant costs and considerable operational time. To mitigate these expenses and simplify the workflow, we subsequently optimized this KASP rapid detection method by utilizing genomic DNA as the template. This new resistance detection technique directly utilizes A. retroflexus genomic DNA as the template, and, by adding specific labelled primers, probes, and enzymes, it can determine whether the ppo2 gene harbors an Arg-128-Gly mutation, thereby rapidly identifying fomesafen resistance in A. retroflexus. Furthermore, we compared the detection efficiency of the new KASP assay, whole plant dose–response assay, and DNA sequencing, all of which produced consistent outcomes, supporting the accuracy and reliability of the KASP rapid detection method. Collectively, we established a rapid resistance detection method based on KASP technology, which is of high reliability and time-saving, and will significantly advance precise management of resistant weeds. Full article

Zero-tillage (ZT) is a conservation soil management approach which relies more heavily on herbicide application for weed control than in ploughed soil. Changes in soil management can influence the structure and organisation of pore space in soil, which drives changes in the transport of particulates and dissolved substances. Formulation of pesticides can be used to change the delivery of active ingredients to soil; however, it is currently unknown how changing the formulation of an herbicide can influence the transport properties between ZT vs. ploughing. We investigated the bioefficacy of two formulations of the herbicide atrazine, a pre- and post-emergence herbicide that inhibits photosystem II. Bioefficacy was assessed using physical measures and survival analysis of an early photosynthesis-dependent weed species, Amaranthus retroflexus L., over time, and soil pore network structure was assessed by analysing three-dimensional images produced by X-ray Computed Tomography. Increasing the herbicide application rate generally improved bioefficacy, though it was reduced in soils managed under ZT. Under herbicide-treated ZT samples, survival time was higher, ranging from 13.4 to 18.2 days compared with 12.6 to 15.4 days in ploughed samples, the mean dry plant mass was higher, ranging from 0.5 to 2.5 mg compared with 0.05 to 0.68 mg in ploughed samples, and the mean total plant length was higher, ranging from 1.73 to 12.1 mm compared with 0.2 to 5.45 mm in ploughed samples. Changes in the soil pore network previously demonstrated to be indicators of preferential transport were correlated with measures of bioefficacy, including pore thickness and connectivity density. Reduced atrazine efficacy under ZT is problematic considering the inherent reliance on chemical methods for weed control, we suggest that pursuing formulation strategies to alleviate potential risks of loss via preferential transport may be fruitful. Full article

Endophytic fungi possess a unique ability to produce abundant secondary metabolites, which play an active role in the growth and development of host plants. In this study, chemical investigations on the endophytic fungus Aspergillus japonicus TE-739D derived from the cultivated tobacco (Nicotiana tabacum L.) afforded two new polyketide derivatives, namely japoniones A (1) and B (2), as well as four previously reported compounds 3–6. Their chemical structures were elucidated by detailed spectroscopic analyses and quantum chemical calculations. In the herbicidal assays on the germination and radicle growth of Amaranthus retroflexus L. and Eleusine indica seeds, compound 1 was found to inhibit the germ and radicle elongation. Notably, compound 2 showed potent herbicidal activity against A. retroflexus L. germ elongation, with an IC₅₀ value of 43.6 μg/mL, even higher than the positive control glyphosate (IC₅₀ = 76.0 μg/mL). Moreover, compound 4 demonstrated strong antibacterial effects against the pathogens Bacillus cereus and Bacillus subtilis, with a comparable MIC value of 16 μg/mL to the positive control chloramphenicol. These findings indicate that the endophytic fungus A. japonicus TE-739D holds significant metabolic potential to produce bioactive secondary metabolites, which are beneficial, providing survival value to the host plants. Full article

Invasive weed species exhibit both advantages, such as the potential for allelochemicals in bioherbicide development, and risks, including their threat to crop production. Therefore, this study aims to identify an allelochemical from Solidago altissima, an invasive weed species. The dose-dependent effects of S. altissima shoot and root extracts (SSE, SRE) on the signaling in the forage crop Trifolium repens and germination in various weed species (Echinochloa oryzicola, Cyperus microiria, Alopecurus aequalis, Portulaca oleracea, and Amaranthus retroflexus) were evaluated. The results showed that the T. repens seedlings treated with root extracts exhibited a significant decrease in plant height, dry weight, and chlorophyll content, along with an increase in H₂O₂ levels. Additionally, antioxidant activities, such as superoxide dismutase, catalase, and peroxidase enzyme activities, were significantly elevated in T. repens treated with SRE. Moreover, SRE treatment significantly inhibited the seed germination of all tested weed species in a concentration-dependent manner. Gas chromatography-mass spectrometry analysis of S. altissima root extract identified a high concentration of methyl kolavenate, a clerodane diterpene predicted to act as a phytotoxic agent. These findings highlight the potential of S. altissima for the development of crop-protective agents while emphasizing its potential risks in agriculture. Full article