Search Results (82)

Rice (Oryza sativa L.) is a staple food crop, feeding more than 3.5 billion people. With the increasing demand for food in the 21st century, weed infestation poses the most significant biotic threat to global food security, and herbicides remain the most effective and economic way to manage it in field. However, weeds can rapidly adapt under herbicide selection pressure due to their high competitiveness, rapid growth, and reproductive capacity. Hence, we collected Echinochloa crus-galli populations from Heilongjiang and Hebei provinces in China and investigated their resistance mechanisms to pyrazosulfuron-ethyl (PSE), a sulfonylurea herbicide that inhibits acetolactate synthase (ALS). Dose–response experiments confirm that the resistant (R) population exhibits 52.9-fold resistance to PSE compared with the susceptible (S) population. Inhibitor bioassays with malathion and NBD-Cl, together with ALS activity assays, ALS gene sequencing, and molecular docking, collectively suggest that resistance is strongly associated with the ALS Trp-574-Leu target-site substitution, with a possible additional contribution from enhanced herbicide metabolism. However, because the S and R populations originate from geographically distinct locations, some of the observed physiological and molecular differences may also reflect inherent population variation. Specifically, the ALS W574L substitution is predicted to reduce key interactions between ALS and PSE. This study provides valuable evidence for the risk of PSE resistance evolution in E. crus-galli and elucidates the molecular mechanism conferring resistance to ALS inhibitors. Full article

The demand for sustainable weed management and the limited discovery of new herbicide molecules have led to high interest in plant-derived bioherbicides, such as the water residues (WRs) from the hydrodistillation of aromatic plants, which contain biologically active secondary metabolites. Here, the bioherbicidal activity of WRs of four aromatic plant species was investigated. Chemical composition of WRs was determined by solid-phase microextraction (SPME) coupled to gas chromatography–mass spectrometry (GC-MS), and their effect was assessed on seed germination and seedling growth characteristics of Avena sterilis, Echinochloa crus-galli, and Zea mays. Five concentrations, i.e., 0, 10, 20, 50, and 100% (v/v), with 100% representing pure WR, were tested. Phenolic monoterpenes dominate WRs in oregano and thyme, and oxygenated monoterpenes in laurel and lavender. Germination and growth responses were dose-dependent and species-specific. Oregano and lavender WRs exhibited the strongest inhibitory effect, reducing weed germination by 82% and 79%, respectively. In contrast, laurel extracts showed weaker germination inhibition. Across all tested species, germination delays were observed, making WRs a promising candidate for weed control. The results also showed that WR reduced root growth by up to 95% and shoot growth by 70–80%. Maize exhibited greater tolerance than the weed species, maintaining higher germination. Overall, WRs represent a promising tool for integrated weed management. Full article

In the conducted study, the structure of weed communities and their dynamics were assessed and compared in relation to plantation age and the species of energy crop. Weed diversity within the stands of the investigated energy crops was evaluated in three-year cycles, from 2006 to 2024. The assessment of weed diversity in the stands of the studied energy crops was conducted in three-year cycles, i.e., in the first year of cultivation (2006—the year of plantation establishment), the fourth year of cultivation (2009), the seventh year of cultivation (2012), the tenth year of cultivation (2015), the thirteenth year of cultivation (2018), the sixteenth year of cultivation (2021), and the nineteenth year of cultivation (2024). The species composition of weed communities and the abundance of individual weed species were determined. The diversity and dominance patterns of weed communities occurring in Salix viminalis, Miscanthus × giganteus, and Phalaris arundinacea were described using two indices: the Shannon–Wiener diversity index and the Simpson dominance index. As a result of the conducted observations, it was found that weed abundance, species diversity, and weed infestation dynamics depended on the energy crop species and the age of the plantation. Greater interannual variability was observed in weed abundance, whereas species richness remained relatively more stable between years. The highest species diversity was recorded in the Salix viminalis plantation, where a total of 53 weed species were identified. In contrast, considerably fewer taxa were found in Miscanthus × giganteus (42 species) and Phalaris arundinacea (41 species). Moreover, it was found that regardless of the energy crop species, segetal weeds dominated during the first years of cultivation, i.e., E. crus-galli, A. spica-venti, A. retroflexus, Ch. album, M. inodora, and V. arvensis. In subsequent years of cultivation, however, the dominant species were ruderal weeds, such as A. vulgaris, T. officinale, and U. dioica, as well as invasive species, e.g., S. canadensis and S. gigantea. In subsequent years, ruderal species became dominant. The Shannon–Wiener diversity and Simpson dominance indices indicated differences in species richness and the relative abundance of individual weed species. The highest values of the Shannon–Wiener diversity index and the lowest values of the Simpson dominance index were recorded in weed communities of Salix viminalis plantations aged 7–16 years after establishment. In contrast, the highest Simpson index values, indicating dominance by one or a few weed species, were observed in the first year of cultivation regardless of the energy crop species, as well as in the 19-year-old Miscanthus × giganteus plantation. Full article

Clove (Syzygium aromaticum (L.) Merr. & L.M. Perry) essential oil (EO)-based nanoemulsions may have a promising future in eco-friendly herbicide development. Clove EO was found to have a high eugenol content of 87.27%. Organic-solvent-free nanoemulsions using clove EO as a bioactive ingredient were fabricated using ultrasonication and microfluidization emulsification methods. Fourier-transform infrared spectroscopy confirmed that both emulsification methods did not affect the EO components. The droplet size of optimized nanoemulsions was determined using dynamic light scattering. The smallest size of 66.9 nm was obtained by microfluidization at 20,000 psi and eight passes. Additionally, the smallest droplet size for a sonicated nanoemulsion was 103.9 nm, obtained by ultrasonication at 20% for 6 min. Transmission electron microscopy confirmed the droplet sizes of both optimized nanoemulsions. In a storage test, both optimized nanoemulsions were stored at 4 °C for at least four weeks. Finally, both nanoemulsions were evaluated on pre-emergence herbicidal activities against Echinochloa crus-galli. The results showed that both nanoemulsions inhibited E. crus-galli germination and seedling growth, and additionally, inhibited seed imbibition and α-amylase activity. Micro-morphological and ultrastructural analysis was observed using a scanning electron microscope and an energy dispersive X-ray spectrometer (SEM-EDS). SEM-EDS micrographs of the treated seeds showed that the seed structure was damaged, especially the endosperm, leading to the inhibition of seed germination. Full article

The infestation of Echinochloa crus-galli (L.) P.Beauv. in crop fields results in significant yield loss in many agricultural systems. Currently, the most effective strategy for controlling E. crus-galli is the application of synthetic herbicides. However, biotypes of E. crus-galli that are resistant to different modes of herbicide action often emerge. Thus, it is necessary to develop alternative control methods and address ecological concerns about synthetic herbicides. During the field survey, we observed diseased E. crus-galli exhibiting symptoms of leaf blight. These symptoms indicate a potential pathogen infection and subsequent phytotoxin production during the pathogenesis. Therefore, we aimed to isolate and identify the phytotoxic substances present in the diseased leaves. Aqueous extracts of the diseased leaves exhibited phytotoxicity, suppressing the growth of Echinochloa crus-galli seedlings in a concentration-dependent manner. A phytotoxic substance was isolated from the leaf extracts through a bioassay-guided separation process using the E. crus-galli bioassay. Spectrum analysis revealed that the phytotoxic substance was monocerin. Monocerin inhibited the growth of coleoptiles and roots of E. crus-galli seedlings at concentrations greater than 30 and 10 μM, respectively, and inhibited germination at concentrations greater than 100 μM. Therefore, monocerin may be involved in the phytotoxic activity exhibited by the extracts of E. crus-galli leaves with blight symptoms. Creating bioherbicides based on the monocerin structure could be an environmentally friendly approach to weed management. Full article

The global food security faces significant threats from phytopathogenic microbes and weeds. In this study, seven secondary metabolites (1–7) were isolated from the insect-associated fungus Leptosphaeria sp. FZN28 in Mecopoda elongata. Their structures were elucidated through a combination of spectroscopic analyses. In bioactive assays, peniciphenalenin E (1) exhibited great antimicrobial activities against Phytophthora capsici and Sclerotinia sclerotiorum, with EC₅₀ values of 8.8 and 10.8 μg/mL, respectively. Scleroderolide (2) demonstrated EC₅₀ values of 20.4 and 14.8 μg/mL against the same strains, respectively. Notably, as seen with in vitro assays, 100 μg/mL of 1 could effectively prevent infection of P. capsici with a protection efficacy of 69.1%, and compounds 1 and 2 at a concentration of 200 μg/mL could greatly inhibit disease development in S. sclerotiorum-infected cole leaves with inhibitory efficacies of 66.9% and 61.0%, respectively. Moreover, the two compounds could also affect the hyphal morphology of S. sclerotiorum and P. capsici via scanning electron microscope and transmission electron microscope. Additionally, compounds 1 and 2 at a concentration of 200 μg/mL could significantly inhibit the radicle growth and germ elongation of monocotyledon weed and dicotyledon weed, Echinochloa crusgalli and Eclipta prostrata. Considering their antimicrobial and herbicidal activities, compounds 1 and 2 showed promise for the development of new bio-pesticides. Full article

Echinochloa crus-galli and E. crus-galli var. mitis are two of the most troublesome rice weeds. Florpyrauxifen-benzyl is one of the most important post-emergence rice herbicides that has been pervasively applied in many countries since 2018. We collected 70 E. crus-galli and 158 E. crus-galli var. mitis populations from rice fields in eastern China in 2022 and tested their sensitivities to florpyrauxifen-benzyl through whole-plant bioassays. A total of 21 days after treatment with florpyrauxifen-benzyl label dose (36 g ai ha⁻¹), 71.4% of E. crus-galli and 70.9% of E. crus-galli var. mitis populations were completely controlled. The GR₅₀ doses (doses causing 50% fresh weight reductions in aboveground parts) of florpyrauxifen-benzyl applied to E. crus-galli populations ranged from 1.4 to 36.9 g ai ha⁻¹, with a baseline sensitivity dose of 4.9 g ai ha⁻¹; those for E. crus-galli var. mitis populations ranged from 1.3 to 97.6 g ai ha⁻¹, with a baseline sensitivity dose of 5.0 g ai ha⁻¹. No significant differences between E. crus-galli and E. crus-galli var. mitis were found in GR₅₀ values. Among 70 E. crus-galli populations, 61.4%, 35.7%, and 2.9% showed no, low, and moderate resistance to florpyrauxifen-benzyl, while among 158 E. crus-galli var. mitis populations, 54.4%, 36.1%, 1.9%, and 1.9% showed no, low, moderate, and high resistance to florpyrauxifen-benzyl, respectively. Moreover, the frequency of florpyrauxifen-benzyl-resistant populations of E. crus-galli var. mitis tended to be higher in southwestern areas. Full article

Weed infestation severely impairs foxtail millet growth, while new herbicide development faces long cycles and high costs. This study examined cyhalofop-butyl (effective against Echinochloa crus-galli (E. crus-galli) in paddy fields) to assess its effects on agronomic traits, antioxidant enzyme activities, malondialdehyde (MDA) content of Jingu 21, and weed control efficacy in foxtail millet fields, aiming to screen safe, effective concentrations. Results showed that sole cyhalofop-butyl inhibited foxtail millet growth: high-dose treatments retained significant agronomic trait inhibition 30 days post-spray. Early post-spray, superoxide dismutase (SOD) and peroxidase (POD) activities showed a “first increase then decrease” pattern, catalase (CAT) a “first decrease then increase” trend, and MDA content rose; index differences from the water control narrowed over time, though 90 g a.i./hm² still caused higher leaf SOD activity and MDA content in later stages. For weed control, cyhalofop-butyl effectively controlled E. crus-galli (control effect “first increase then decrease,” 90 g a.i./hm² optimal) and Digitaria sanguinalis (D. sanguinalis) (control effect rising over time) in foxtail millet fields. On the whole, 22.5 g a.i./hm² and 45 g a.i./hm² of cyhalofop-butyl are safe for Jingu 21, and 67.5 g a.i./hm² is also a safe concentration, so 45–67.5 g a.i./hm² can be preferred for comprehensive weed control. Full article

The increasing implementation of drift-reduction regulations in agriculture has driven the widespread adoption of drift-reducing spray nozzles. However, concerns remain about their impact on the biological efficacy of foliar-applied herbicides, particularly at early weed growth stages. This study evaluated the bio-efficiency of various drift-reducing flat-fan nozzles across three weed species (Chenopodium album, Solanum nigrum, and Echinochloa crus-galli), two growth stages, and six herbicides differing in mode of action and formulation properties. Dose–response bioassays were conducted using eight nozzle–pressure combinations under controlled greenhouse conditions. Spray characteristics, including droplet size distribution, coverage, contact angle, and surface tension, were quantified to elucidate interactions affecting herbicide efficacy. The results showed that nozzle effects were more pronounced for high-surface-tension formulations and poorly wettable weed targets. Several coarser droplet drift-reducing nozzles (e.g., ID3, APTJ) showed inferior performance in controlling small C. album and S. nigrum targets with bentazon and erectophile E. crus-galli targets with cycloxydim. At the same time, nozzle choice was less critical for tembotrione and nicosulfuron spray solutions, which have low surface tension. Across weed species, growth stages, and herbicides, nozzles producing finer, slower droplets demonstrated superior and more consistent performance compared to those producing larger, faster droplets. These findings offer science-based guidance for selecting nozzle types that balance drift mitigation with effective weed control under current and future regulatory constraints. Full article

The long-term application of traditional chemical herbicides has caused a significant escalation in herbicide resistance of barnyard grass (Echinochloa crus-galli). As an eco-friendly alternative, biological herbicides demonstrate substantial application potential. Acknowledging the growing herbicide resistance of E. crus-galli, this study aimed to screen target bacteria with inhibitory effects on the growth for bio-herbicide development. By using ungerminated E. crus-galli seeds as the screening substrate, a bacterial strain (BFYBC-8) with potent inhibitory activity was isolated and identified as Brucella pseudorignonensis. Pot experiments revealed that inoculation with B. pseudorignonensis BFYBC-8 significantly suppressed E. crus-galli growth, reducing plant height by 16.7% and root length by 85.1%, while markedly inhibiting biomass accumulation. Fluorescent labeling with green fluorescent protein (GFP) showed that BFYBC-8 successfully colonized the root intercellular spaces of E. crus-galli and extended continuously along the tissue matrix. Additionally, the strain’s supernatant metabolic products exhibited exceptional thermostability: inhibitory activity against E. crus-galli was maintained after thermal treatment at 28 °C, 60 °C, 80 °C, and 100 °C. Crucially, the bacterium displayed no toxicity to agronomically important crops such as rice, wheat, and corn. This study highlights B. pseudorignonensis BFYBC-8 as a promising candidate for bioherbicide development and provides an important reference for applying seed-associated pathogenic bacteria in developing bioherbicides for sustainable weed management. Full article

Barnyard grass is the most problematic weed in paddy fields in Ningxia. Its substantial morphological variation complicates both identification and control, yet the genetic diversity of barnyard grass infesting paddy fields in Ningxia has not been thoroughly studied. In this research, we analyzed the genetic diversity of 46 barnyard grass populations from Ningxia’s paddy fields based on the assessment of morphological traits, DNA barcoding, and SCoT-targeted gene markers. Nine morphological traits were quantitatively analyzed, among which three phenological traits, i.e., leaf length, stem diameter, and plant height, exhibited notable variations. Correlational analysis revealed a positive relationship between morphological traits and multi-herbicide resistance profiles. To assess genetic diversity, four DNA barcodes (ITS, psbA, matK, and trnL-F) were used, among which ITS demonstrated the strongest potential in single-gene barcoding for barnyard grass species identification. Cluster analysis based on ITS barcode sequences was performed to group the populations into five main categories. Additionally, SCoT marker analysis using six primers was performed to classify the 46 barnyard grass samples into five groups. The results showed that the predominant barnyard grass species in Ningxia were E. colona, E. crus-galli var. Formosensis, E. crusgalli, E. oryzoides, and E. crusgalli var. Zelayensis, with E. colona being the most prevalent. The differences observed between the morphological and molecular marker-based classifications were method-dependent. However, both SCoT molecular marker technology and DNA barcoding contributed to identifying the genetic diversity of barnyard grass. Taken together, our study revealed significant morphological and genetic variations among barnyard grass populations, which correlated with herbicide sensitivity in Ningxia’s paddy fields, underscoring the necessity for an integrated weed management approach to combat this troublesome weed species. Full article

Echinochloa crus-galli (L.) P. Beauv. (EC), E. crus-galli var. mitis (Pursh) Petermann (ECM), and E. glabrescens Munro ex Hook.f. (EG) are all troublesome weeds and frequently managed as one species on rice (Oryza sativa) fields. To examine inter- and intra-specific differences in seed germination responses to drought stresses, we conducted seed germination experiments with 57 EC, 112 ECM, and 92 EG populations. In all drought stress treatments, EC exhibited higher and faster germination than ECM and EG. Under 0 MPa, seed germinations of all populations initiated on 3 DAT (day after treatment). Accumulative seed germination percentages of EC, ECM, and EG under −0.1 MPa did not show significant differences with the same species treated with 0 MPa, while significantly decreased with the osmotic potential treated decreasing to −0.4 MPa or lower. OR₅₀ values (the osmotic potential at which 50% germination occurs) for EC, ECM, and EG were −0.55 MPa, −0.49 MPa, and −0.45 MPa, respectively. Intra-specific variation within all three species increased as osmotic potential decreased from −0.1 MPa to −0.8 MPa. Moreover, seed germination was significantly correlated with 1000-seed weight and latitudes of population-collected locations. In four treatments, seeds produced by Echinochloa weeds growing in transplanted rice fields exhibited significantly higher germination percentages than those from direct-seeded rice fields. Full article

Flusulfinam is a 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide applied post-emergence (POST) to control Echinochloa crus-galli (L.) P.Beauv., Leptochloa chinensis (L.) Nees, Digitaria sanguinalis (Linn.) Scop. and other annual weeds in directly seeded and transplanted paddy fields in China, registered in September 2024. Notably, compared with other HPPD inhibitors in rice, flusulfinam exhibits consistently high safety in both japonica and indica rice varieties. Meanwhile, flusulfinam has no target-site cross-resistance with traditional acetolactate synthase (ALS)-inhibiting, acetyl-CoA carboxylase (ACCase)-inhibiting, and auxin herbicides. Moreover, as the only heterocyclic-amide-structured herbicide in the HPPD inhibitors, it poses a low risk of metabolic cross-resistance with the other HPPD inhibitors, making it a promising candidate for managing herbicide-resistant weeds in rice fields. In this study, the baseline sensitivity to flusulfinam of E. crus-galli and L. chinensis in paddy fields in China was established using dose–response assays between June and October 2023. Thirty-nine populations of E. crus-galli and forty-three populations of L. chinensis, collected from rice fields across various major rice-producing regions in China, exhibited susceptibility to flusulfinam. The GR₅₀ values ranged from 0.15 to 19.39 g active ingredient (a.i.) ha⁻¹ for E. crus-galli and from 7.82 to 49.92 g a.i. ha⁻¹ for L. chinensis, respectively, far below the field recommended rate of flusulfinam. Meanwhile, the GR₅₀ values of E. crus-galli and L. chinensis to flusulfinam were both distributed as a unimodal curve, with baseline sensitivity (GR₅₀b) of 6.48 g a.i. ha⁻¹ and 22.38 g a.i. ha⁻¹, respectively. The SI₅₀ value showed 129.27-fold and 6.38-fold variability in flusulfinam sensitivity among the 39 E. crus-galli field populations and 43 L. chinensis filed populations, while the variability declined to 2.99-fold and 2.23-fold when the SI₅₀b value was used. This study substantiated the efficacy of flusulfinam against E. crus-galli and L. chinensis in Chinese paddy fields and furnished a benchmark for monitoring temporal variations in the susceptibility of field populations of E. crus-galli and L. chinensis to flusulfinam. Full article

Echinochloa species are troublesome weeds that cause serious problems in paddy fields. Due to the fact that the genus Echinochloa comprises numerous species and subspecies, research on its seed germination and emergence ecology is still insufficient. In this study, the influence of varying temperatures; light, osmotic, and saline conditions; and depth of seed burial on the germination of Echinochloa seeds and the emergence of seedlings was determined through laboratory and pot tests: E. crus-galli var. crus-galli, E. crus-galli var. mitis, E. crus-galli var. praticola, and E. caudata. Seed germination of the constant temperatures in the four Echinochloa taxa was examined between 15 and 40 °C, and optimum germination occurred over the following temperature ranges: 25–35 °C for E. crus-galli var. crus-galli; 15–25 °C for E. crus-galli var. mitis; 15–40 °C for E. crus-galli var. praticola; and 15–35 °C for E. caudata. Fluctuating temperatures were conducive to seed germination in all four Echinochloa taxa. Except for E. crus-galli var. crus-galli and E. crus-galli var. mitis exposed to very acidic conditions (pH = 4), germination of seedlings from the four taxa of Echinochloa was not evidently affected by pH or light. Seed germination of the four Echinochloa taxa decreased as water stress decreased (<−0.2 MPa); however, it occurred across a wide spectrum of salt concentrations (0–320 mM NaCl). The seeds that were placed 0–0.5 cm below the surface had the highest rate of seedling emergence, which declined gradually as burial depth increased. This result demonstrates that deep tillage is an efficient management method for decreasing the seedling emergence of various weed species. This study’s findings will enhance our comprehension of the conditions necessary for the germination and emergence of Echinochloa seeds, as well as furnish information that may assist in managing its growth. Full article

Developing processes that contribute to the valorization of vegetable wastes is of great importance since these residues are characterized by being of high quality, having a huge potential for valorization. However, upcycling vegetables residues and defining specific applications for the value-added products obtained might be a challenge, and they should be tackled by means of different and complementary innovations. In the present study, broccoli and white cabbage discards were transformed into powdered products by means of selected techniques and conditions, which have been explored for applications in the agri-food sector. The obtained brassica powders were rich in bioactive compounds such as phenolics and isothiocyanates. Their antioxidant properties in response to in vitro digestion were evaluated to assess the potential of the products as functional food ingredients. On the other hand, brassica powders were tested as bioherbicides. For that purpose, inhibition tests on weed germination and growth of weeds from agricultural soil seedbank and selected species (Lolium rigidum, Papaver rhoeas, Portulaca oleracea, and Echicnochloa crus-galli) were performed under controlled greenhouse conditions. In vitro simulated digestion studies demonstrated that bioactive constituents of powders were progressively released during digestion, and consequently, a part of them could be finally absorbed and, thus, provide their beneficial effect. Brassica bioproducts significantly reduced the germination of weeds from the agricultural soil seedbank, and the selected weed species tested, namely L. rigidum, P. rhoeas, P. oleracea, and E. crus-galli. Powders also showed a negative effect on the root weight and length of dicotyledonous weeds from the soil seedbank and L. rigidum, whereas a stimulatory effect was observed on the spring–summer species, E. crus-galli and P. oleracea. The results of this work contribute to extending the range of applications for brassica industrialization wastes. Full article