Search Results (267)

Aeschynomene indica L. has become a problematic weed in the upland direct-seeding rice fields of the lower Yangtze River region, China, leading to substantial yield reductions. A comprehensive understanding of its seed germination ecology and response to herbicides is crucial for developing effective control strategies. This study examined the effects of major environmental factors including temperature, light, pH, salt stress, osmotic potential, and burial depth on seed germination of A. indica and assessed the efficacy of 20 commonly used herbicides in rice under controlled conditions. Results revealed that germination was highly sensitive to temperature, with optimum constant and alternating temperatures of 35 °C and 40/30 °C (day/night), respectively, both achieving germination rates above 90%. The seeds were non-photoblastic, maintaining a high germination rate of 83.33% under complete darkness. Germination remained consistently high across a broad pH range from 4 to 9, with rates ranging from 83.33% to 96.67%. Salt and osmotic stresses markedly suppressed germination, with EC₅₀ values of 195.08 mmol·L⁻¹ NaCl and −0.43 MPa, respectively. Seedling emergence decreased significantly with increasing burial depth, with no emergence occurring at depths greater than 7 cm. The EC₅₀ for emergence was 4.21 cm. Among the herbicides screened, saflufenacil and mesotrione were the most effective pre-emergence treatments, with GR₅₀ values of 5.38 and 12.02 g ai ha⁻¹, respectively. Florpyrauxifen-benzyl and fluroxypyr-meptyl exhibited the highest post-emergence activity, with GR₅₀ values of 0.20 and 19.69 g ai ha⁻¹, respectively. These results underscore the high ecological adaptability of A. indica to paddy fields conditions and provide a scientific foundation for integrating chemical control with cultural practices such as deep tillage into sustainable weed management systems for paddy fields. Full article

Weedy rice (Oryza sativa L.) presents a formidable challenge in global paddy cultivation due to its morphological similarity to cultivated rice, making its eradication difficult. To address this, an integrated weed management system (IWMS) was developed and collected across various regions in Kaohsiung, Taiwan, from 2018 to 2020. This study evaluated the efficacy of the IWMS in controlling the spread of weedy rice through systematic applications in three distinct agricultural zones: Meinong Contractual (MC), Meinong Public Stock (MP), and Shanlin Public Stock (SP). The data reveal a consistent decline in weedy rice invasion with sustained implementation of the IWMS, alongside improvements in seed purity and corresponding grain quality. These enhancements not only mitigate the adverse effects on seed purity but also elevate grain quality, thereby curtailing yield losses and bolstering economic returns. Further analysis indicates that the patterns of weedy rice invasion correlate strongly with geographical and agronomic variables, such as the source of seedlings, land preparation techniques, field management, and the sharing of agricultural implements. Consequently, raising farmer awareness and providing specialized training on management strategies are crucial for effective prevention of weedy rice. Full article

The H9N2 avian influenza virus (AIV) is difficult to prevent and control because of its low pathogenicity and frequent mutation. In a previous study, the HA (hemagglutinin) protein of H9N2 was expressed in a rice endosperm reactor and prepared into a subunit vaccine to immunize chickens and mice, both of which exhibited a good immunity effect. The results of the intermediate tests of the transgenic strains (AIV-1 and AIV-3) showed that the HA gene can be stably expressed. Agronomic traits, such as plant height and number of grains, were significantly optimized in the transgenic strains. Moreover, no exogenous HA genes were found in the leaves of the weeds, and it was initially determined that there was no risk of gene drift. This study provides key technical support for the commercialization of plant subunit vaccines for avian influenza viruses. 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

Weedy rice (Oryza spp.) has become one of the most harmful weeds in rice fields worldwide. It is a conspecific plant of cultivated rice (Oryza sativa L.) belonging to the genus Oryza, widely occurring in global rice production systems with a cosmopolitan distribution across major rice-growing regions. Due to its unique biological characteristics, such as strong environmental adaptability, stress resistance, seed shattering propensity, seed dormancy, and competitive dominance, weedy rice can rapidly proliferate and persist in fields, posing a severe threat to rice production systems. This review summarizes the current research progress on the biological characteristics of weedy rice and introduces the significant differences in biological characteristics between weedy and cultivated rice, such as phenotypic diversity, seed shattering, dormancy, strong competitiveness, stress resistance, and early maturity. These distinct biological traits, which significantly differ from cultivated rice, serve as essential mechanisms in the survival strategy of weedy rice. Our review will provide a theoretical reference for a deeper understanding of weedy rice and its integrated management. 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

Tolprocarb (TPC), a fungicide primarily used for controlling rice blast, was recently shown to stimulate disease resistance in rice. To elucidate the molecular basis of this immunostimulatory effect, we conducted transcriptomic, metabolic, and field-based analyses focusing on diterpenoid phytoalexins, key antimicrobial and allelopathic compounds in rice. Microarray analysis revealed that TPC treatment induced a broad transcriptional activation of genes involved in phytoalexin biosynthesis, including DPF, a master regulator of diterpenoid metabolism. Consistent with this, LC-MS/MS analyses confirmed the accumulation of momilactones A and B, as well as phytocassanes B, C, and E, in rice leaves after TPC application, a response not observed with conventional resistance inducers such as probenazole or carpropamid. In root tissues under controlled conditions, phytoalexin accumulation was limited, and exudation into the rhizosphere was minimal. However, field experiments showed that TPC treatment led to a transient increase in leaf momilactones around 14 days post-transplanting, followed by increased exudation into the rhizosphere at 21 days. Notably, this increase in root exudation coincided with a reduction in total weed biomass, although weed species composition remained unchanged. These findings suggest that TPC not only enhances rice immunity through phytoalexin induction but may also contribute to weed suppression via allelopathic root exudates in field settings. Our study highlights a dual role for TPC in rice cultivation, boosting disease resistance and suppressing weed growth, and underscores the potential of phytoalexin-focused strategies for integrated crop protection. Full article

Chinese milk vetch (CMV; Astragalus sinicus L.), serving as winter green manure in rice cropping systems, is widely adopted in the southern China. Field experiments including different incorporation regimes (CMV incorporation, urea substitution incorporation and fertilizer-free incorporation), times (45 days, 30 days and 15 days before rice transplanting) and methods (no flooding, intermittent flooding and continuous flooding) were conducted from 2022 to 2024 to determine the optimal time and method for CMV incorporation that could improve soil nutrients, reduce rice-associated weed infestation, and increase rice yield. Delaying CMV incorporation was beneficial to the accumulation of dry matter and organic matter content in CMV shoots and the increase in the total nitrogen content of the soil before rice transplanting. Broadleaf weed infestation was significantly influenced by flooding method, CMV incorporation and incorporation time. Delaying CMV incorporation combined with flooding significantly reduced the density of broadleaf weeds. Grassy weed infestation was only significantly affected by the flooding method, with significantly lower density under flooding conditions compared to non-flooding conditions when other treatments were consistent. Sedge weed infestation was not affected by any of the experimental treatments. Compared with conventional CMV incorporation (incorporated 30 days before rice transplanting without flooding), incorporating CMV 15 days before rice transplanting with flooding (continuous or intermittent flooding) resulted in a 59.20–66.86% reduction in rice-associated weed infestation. Rice yield was also increased with a delay in CMV incorporation, which mainly manifested in increases in panicle number and seed setting rate. Incorporating CMV 15 days before rice transplanting increased rice yield by 5.34–13.24% compared to conventional CMV incorporation. Therefore, considering the comprehensive effects on soil nutrients, weed infestation and rice yield, incorporating CMV 15 days before rice transplanting combined with intermittent flooding is a recommended green manure management practice in green manure–rice rotation systems. Full article

Pesticide usage in the integrated rice–crayfish system has aroused lots of attention all over the world. Especially in China, fish farmers often use copper sulfate and pendimethalin to remove moss from aquaculture water and glyphosate to remove weeds in and around crayfish–crab mixed culture ponds. To explore the stress response mechanism of CuSO₄, pendimethalin, and glyphosate to the hepatopancreas of Procambarus clarkii (Girard, 1852), seven treatment groups including control, CuSO₄ (1 and 2 mg·L⁻¹), pendimethalin (PND, 5 and 10 μg·L⁻¹), and glyphosate (5 and 10 μg·L⁻¹) experimental groups were set up; the transcriptome responses were detected at 4, 8, and 12 days, respectively. The irregular structure and vacuoles were shown in the hepatopancreas for 2 mg·L⁻¹ CuSO₄ and 10 μg·L⁻¹ glyphosate exposures at 12 d, while narrowed hepatic sinusoids were revealed after 10 μg·L⁻¹ pendimethalin exposure. The pathways of ribosome, lysosome, and peroxisome were significantly enriched for differential expression genes (DEGs); in addition, tyrosine metabolism, starch, and sucrose metabolism were enriched under the stress of the three inputs. Genes in related pathways such as glycerophospholipid metabolism, oxidative phosphorylation, and glycerolipid metabolism also changed, and the expression of genes associated with oxidative phosphorylation changed significantly under the stress of the three inputs. Oxidative stress, neurotoxicity, metabolism, and energy supply have been significantly affected by the above herbicide exposure. High concentrations and/or long-term duration exposure may result in metabolic disorders rather than eliminate toxicity through adaptability responses. Full article

Agrivoltaics represents a crucial technology and an innovative solution to promote sustainability. After a cropping season in an agrivoltaic system in Northern Italy, this study investigated the floristic composition and biomass of weed communities across three crops, evaluating their variation under shaded and full light conditions. In addition, the research assessed the role of uncultivated grassland areas in agrivoltaic-shaded conditions by quantifying their biomass and evaluating their potential feed value. Weed floristic diversity and biomass were surveyed at three different times. Soil and canopy parameters were analyzed in relation to photosynthetically active radiation (PAR). Grassland biomass was assessed after four different cuts and its suitability as a feed source was evaluated by the pastoral value and near infrared (NIR) spectroscopic analysis. Results showed that tomato had the lowest weed presence, and Setaria italica and Sorghum halepense were predominant in rice, while in durum wheat, higher nutrient availability favored Echinochloa crus-galli and Cirsium arvense. In weed community composition and biomass, no significant differences were observed for the effect of different light conditions (sun/shadow), and this may be attributed to their high environmental plasticity. PAR was strongly correlated with both soil and canopy temperatures. The analysis of floristic composition, biomass yield, pastoral value and nutritional quality of grassland vegetation indicated that spring cuts can be effectively used as forage, including for grazing. These findings suggest that integrating livestock activities could offer a win–win strategy for managing uncultivated areas within agrivoltaic systems, thereby enhancing their sustainability under organic farming practices. Full article

Despite our preliminary research about the inductive effect of exogenous abscisic acid (ABA) on the weed-suppressive activity of rice in a hydroponic system, there is a lack of knowledge regarding the induction mechanism for ABA application to enhance the ability for weed control underground. Here, two pot experiments using rice–barnyard grass mixed culture were conducted to investigate the effects of exogenous ABA treatment on weed inhibition strategies in both allelopathic rice PI312777 (PI) and non-allelopathic rice Lemont (Le). The largest observed weed inhibition changes in the two rice accessions both occurred with the 9 μmol/L ABA treatment. ABA induction on PI significantly increases the inhibitory effect on the plant height of barnyard grass with root contact and root segregation by 25.7% and 19.1%, respectively, with 23.5% increases observed in Le rice with root contact and no significant increases in plants with root segregation with nylon mesh. ABA induction also significantly increased the root distribution in the soil of Le. Compared with the uninduced group, ABA treatment significantly elevated the total amounts of reversibly adsorbed phenolic acids in the two soil layers of PI and the irreversibly adsorbed phenolic acids in Le soil layers. Furthermore, exogenous ABA could change the bacterial composition in rhizosphere soil of the two rice accessions, with the change in the species composition in the rhizosphere soil of the allelopathic rice PI being greater. Importantly, the bacterial compositions (Anaerolineales, Bacteroidales, and Myxococcale) in the PI rhizosphere soil of rice induced by ABA were more related to the contents of reversibly adsorbed phenolic acids in the soil. However, the core bacterial compositions that promote plant growth (Sphingomonadales, Cyanobacteriales, and Rhizobiales) in the Le rhizosphere soil were more related to the contents of irreversibly adsorbed phenolic acids in the soil. These findings suggested that the ABA induction mainly changed root distribution and core bacterial compositions in Le to enhance resource competition, whereas it stimulated the release of reversibly adsorbed phenolic acids to modulate the specific bacterial compositions in rhizosphere soil of PI and to strengthen allelopathic effects. Full article

Rice membrane-covered cultivation offers notable agronomic advantages, including effective weed suppression and improved moisture retention. However, current mechanized approaches remain constrained by high labor requirements, low operational efficiency, and the inherent fragility of biodegradable membranes. To address these limitations, this study integrates a high-speed synchronous membrane-covering device, governed by a PSO-Fuzzy PID control algorithm, into a conventional rice transplanter. This integration enables precise coordination between membrane-laying and transplanting operations. The mechanical properties of the membranes were analyzed, and a tension evaluation model was developed considering structural parameters and roll diameter variation. Experimental tests on three biodegradable membranes revealed an average thickness of 0.012 mm, a longitudinal tensile force of 0.57 N, and a tensile strength of 2.85 N/mm. The PSO algorithm was employed to optimize fuzzy PID parameters (K = 5.3095, K_p = 10.6981, K_i = 0.0100, K_d = 8.2892), achieving adaptive synchronization between membrane output speed and transplanter travel speed. Simulation results demonstrated that the PSO-Fuzzy PID reduced rise time by 53.13%, stabilization time by 90.58%, and overshoot by 3.3% compared with the conventional PID. In addition, a dedicated test bench for the membrane-covering device was designed and fabricated. Orthogonal experiments determined the optimal parameters for the speed-measurement system: a membrane pressure of 5.000 N, a roller width of 28.506 mm, and a placement angle of 0.690°. Under these conditions, the minimum membrane-stretching tension was 0.55 N, and the rotational speed error was 0.359%. Field tests indicated a synchronization error below 1.00%, a membrane-width variation rate below 1.50%, and strong anti-interference capability. The proposed device provides an effective solution for intelligent and fully mechanized rice transplanting. Full article

Weeds pose a significant challenge to agricultural productivity, requiring control strategies that are both effective and environmentally sustainable. Therefore, this study evaluated the inhibitory potential of aqueous extracts from Ricinus communis L. leaves to manage the weeds Oryza sativa L. (weedy rice) and Cyperus ferax. Extracts were obtained through pressurized liquid extraction using water as the solvent. Bioassays were conducted during pre- and post-emergence stages by foliar spraying 15 and 30 days after sowing (DAS). The effect of extraction time (1–30 min) on inhibitory efficacy was also assessed. Chemical profiles of the extracts were characterized using high-performance liquid chromatography. The extracts significantly inhibited seed germination, with suppression rates reaching 92.7%. Plant growth was also diminished, particularly with earlier treatments (at 15 DAS), resulting in reductions of up to 32% and 53% in shoot length, and 69% and 73% in total dry mass for O. sativa L. and C. ferax, respectively. Mortality rates of O. sativa L. and C. ferax reached 64% and 58%, respectively. Phenolic compounds were identified in the extracts, and higher concentrations were observed at shorter extraction times. These findings underscore the potential of R. communis L. leaf extracts as an ecologically sustainable alternative for weed management, providing an effective and natural approach that may reduce reliance on synthetic herbicides and mitigate their environmental impact. Full article

Barnyard grass is a major noxious weed in paddy fields. Accurate and efficient identification of barnyard grass is crucial for precision field management. However, existing deep learning models generally suffer from high parameter counts and computational complexity, limiting their practical application in field scenarios. Moreover, the morphological similarity, overlapping, and occlusion between barnyard grass and rice pose challenges for reliable detection in complex environments. To address these issues, this study constructed a barnyard grass detection dataset using high-resolution images captured by a drone equipped with a high-definition camera in rice experimental fields in Haicheng City, Liaoning Province. A lightweight field barnyard grass detection model, YOLOv8n-SSDW, was proposed to enhance detection precision and speed. Based on the baseline YOLOv8n model, a novel Separable Residual Coord Conv (SRCConv) was designed to replace the original convolution module, significantly reducing parameters while maintaining detection accuracy. The Spatio-Channel Enhanced Attention Module (SEAM) was introduced and optimized to improve sensitivity to barnyard grass edge features. Additionally, the lightweight and efficient Dysample upsampling module was incorporated to enhance feature map resolution. A new WIoU loss function was developed to improve bounding box classification and regression accuracy. Comprehensive performance analysis demonstrated that YOLOv8n-SSDW outperformed state-of-the-art models. Ablation studies confirmed the effectiveness of each improvement module. The final fused model achieved lightweight performance while improving detection accuracy, with a 2.2% increase in mAP_50, 3.8% higher precision, 0.6% higher recall, 10.6% fewer parameters, 9.8% lower FLOPs, and an 11.1% reduction in model size compared to the baseline. Field tests using drones combined with ground-based computers further validated the model’s robustness in real-world complex paddy environments. The results indicate that YOLOv8n-SSDW exhibits excellent accuracy and efficiency. This study provides valuable insights for barnyard grass detection in rice fields. Full article

This study evaluated the application of the aqueous extract from Baccharis trimera (Less) DC. in the control of weed species Oryza sativa L. and Cyperus ferax Rich. during the germination and early development stages. Extracts were obtained through pressurized liquid extraction using kinetic assays. Shorter extraction times (1 to 10 min) showed extracts with higher inhibitory effects on seed germination, shoot and root lengths, and fresh and dry mass of the plants. The survival of treated plants was also affected, especially during the early stages of development, reaching up to 40% of mortality. HPLC analysis identified phenolic compounds such as ferulic acid, rutin, quercitrin, and quercetin, with higher concentrations found in the extracts obtained at shorter times of extraction. The reduction in these compounds over longer extraction times was correlated with decreased inhibitory activity. The results indicate that the aqueous extract of B. trimera (Less) DC. holds potential for ecological weed management, standing out as a viable alternative to reduce weed resistance to synthetic herbicides. Full article