Understanding weed community structure is essential for designing sustainable integrated weed management (IWM) strategies in perennial fruit systems. This study aimed to characterize the floristic composition, abundance, and spatial structure of weed communities in jackfruit (Artocarpus heterophyllus Lam.) orchards across Vinh Long Province, Vietnam. Field surveys were conducted during the main rainy season of 2024 using systematic quadrat sampling across multiple agroecological zones. A total of 35 weed species in 18 families were recorded, with Poaceae being the most dominant family (10 species, 28.6%), followed by Asteraceae and Cyperaceae (4 species, 11.4%). Quantitative metrics including density, mean field density (MFD), relative MFD, cover, and multiplied dominance ratio (MDR) identified a consistent group of dominant species: Mexican primrose-willow [Ludwigia octovalvis (Jacq.) P.H. Raven], billygoat-weed [Ageratum conyzoides L.], and carpet grass [Axonopus compressus (Sw.) P. Beauv.], while sedges such as five-angled fimbristylis [Fimbristylis quinquangularis (Vahl) Kunth] also contributed significantly. Hygrophilous species such as shiny bush [Peperomia pellucida (L.) Kunth], centella [Centella asiatica (L.) Urb.], and Ceylon pouzolzia [Pouzolzia zeylanica (L.) Benn.] showed high mean occurrence field density (MOFD), whereas A. conyzoides and L. octovalvis dominated relative MFD, indicating adaptation to high-light environments. Diversity indices (Margalef’s richness, Shannon’s H′, Pielou’s evenness, and Simpson’s dominance) differed modestly among agroecological regions. Ordination analysis grouped species along a gradient primarily associated with density and cover. Similarity indices (Jaccard and Sørensen) were uniformly high (mostly >0.75), suggesting strong species overlap between regions. Notably, community composition varied across orchards, with some orchards exhibiting lower species mixing than others. Weedy rice (Oryza sativa f. spontanea) was detected but was relatively infrequent. These findings provide a quantitative baseline for designing IWM strategies in perennial fruit systems. Specifically, the results support a transition away from routine herbicide use toward ecologically based practices such as mowing before flowering and selective suppression of high-importance weeds, tailored by orchard age and site conditions.

Corn poppy (Papaver rhoeas L.) is a problematic weed in cereal farms in Ireland, necessitating continuous herbicide use to protect crop yields. In 2022, poor control with acetolactate synthase (ALS) inhibitors and auxin-mimic herbicides was reported by growers/advisors in two resistance-suspect populations, namely PAPRH-R1 and PAPRH-R2. In this study, we quantified their resistance to both herbicide modes of action and investigated the underlying mechanisms. ALS inhibitor dose–response experiments revealed that both populations had ED50 and GR50 resistance indices (RIs) above 120 to thifensulfuron + tribenuron, mesosulfuron + iodosulfuron + amidosulfuron, and metsulfuron, and values of 4 to 13 to florasulam + pyroxsulam. Results of 2,4-D dose–response assays revealed higher resistance in PAPRH-R2 (ED50 and GR50 RI > 9.1) than PAPRH-R1 (ED50 and GR50 RI > 3.4). ALS gene sequencing detected Pro-197 mutations in all sequenced plants from both resistant populations. Pretreatment with piperonyl butoxide (PBO, a cytochrome P450 inhibitor) reversed 2,4-D resistance with GR50, the more sensitive response parameter, decreasing from 680.8 to 84.9 g ha−1 in PAPRH-R1 and from 2,508.9 to 456.8 g ha−1 in PAPRH-R2, both well below the recommended label rate of 1,000 g ha−1. The 14C-2,4-D assays ruled out reduced absorption or translocation as resistance mechanisms. Sensitivity screening further revealed incomplete control with other postemergence foliar herbicides tested at half and full recommended label rates, except for fluroxypyr + halauxifen, which provided complete control of PAPRH-R1 at the full rate, and glyphosate, which provided complete control of PAPRH-R1 and PAPRH-R2 at both rates. This is the first report of multiple resistance in P. rhoeas in Ireland involving ALS target-site mutations and likely P450-mediated 2,4-D metabolism. As cultural/nonchemical control of broadleaf species is difficult, the continued availability of preemergence or autumn residual herbicides, together with effective auxin mimics and stewardship practices, will remain essential for managing these species, including P. rhoeas, in cereal crops.

To address the complexity and excessive reliance on expert experience in tuning fuzzy proportional-integral-derivative (PID) controller parameters, this study proposes a variable-rate spraying control system that integrates an improved beetle antennae search (IBAS) algorithm with fuzzy PID control. To evaluate the feasibility of the system, a mathematical transfer function of the variable-rate spraying system was constructed, and a flow control simulation platform was established for simulation analysis. The IBAS algorithm was developed to overcome the limitations of conventional BAS, which is prone to premature convergence and limited search precision. The improvements include a hybrid disturbance strategy to enhance individual search capability and a simulated annealing mechanism to prevent the algorithm from being trapped in local optima. Using the IBAS algorithm, the proportional and quantization factors of the fuzzy PID controller were optimized offline to obtain the optimal parameters. The IBAS–fuzzy PID controller was then compared in simulation with conventional PID, fuzzy PID, and BAS-optimized fuzzy PID controllers. The simulation results demonstrated that the IBAS–fuzzy PID algorithm achieved higher flow control accuracy than existing methods. Field experiments were conducted to further validate the effectiveness of the improved algorithm under practical conditions. The results indicated that the IBAS-optimized fuzzy PID controller outperformed the three other control methods in terms of flow control accuracy. Overall, both simulation and field results confirm that the proposed IBAS algorithm for fuzzy PID parameter optimization significantly enhances response speed, control precision, and overshoot reduction, providing a novel approach and potential application for variable-rate spraying technology.

Strategic soil inversion is advocated as a periodic weed management strategy, typically recommended every 4 to 8 yr if the goal is to delay the evolution of herbicide resistance. It is assumed that the weed seeds buried during the inversion process will lose viability during this period. However, long-term seedbank persistence following soil inversion has not been investigated. If the buried seeds retain viability, subsequent inversions or other deep-tillage operations may return them to the soil surface, potentially replenishing the weed seedbank. The current study identified 30 sites within the wheatbelt of Western Australia (in 2020) that had previously been subject to a single soil inversion event, to investigate viability of the buried seed. At each site, soil was sampled at 10-cm increments from 0 to 40 cm, and weed seedling emergence from these samples was assessed during the following year. Weed emergence was dominated by six species: rigid ryegrass (Lolium rigidum Gaudin), subterranean clover (Trifolium subterraneum L.), prostrate knotweed (Polygonum aviculare L.), clammy goosefoot [Dysphania pumilio (R. Br.) Mosyakin & Clemants], capeweed [Arctotheca calendula (L.) Levyns], and ripgut brome (Bromus diandrus Roth). Weed emergence was greatest from the 10- to 20-cm soil depth, with limited weed emergence beyond this depth, despite inversion operations generally placing topsoil below 20-cm depth. Of the six predominant species, the seedbank persisted for at least 8 yr, except for B. diandrus. This species did not emerge from sites where the inversion was performed more than 2 yr before the survey. This likely reflects species-specific differences in seed size and seedling emergence depth, as B. diandrus produces relatively large seeds capable of emerging from 10 to 20 cm (i.e., the most common burial depth). The findings confirm that the buried seedbank for most species remains viable over extended periods.

Palmer amaranth (Amaranthus palmeri S. Watson) poses a significant threat to northeastern U.S. crop production due to its rapid growth, prolific seed production, and evolving herbicide resistance. This study characterized the response of four A. palmeri populations from New York (NY) and New Jersey (NJ) to postemergence applications of atrazine, a photosystem II (PSII) inhibitor, and mesotrione, a hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor. Dose–response bioassays revealed that two NY populations (NY-GEN and NY-STE) exhibited high-level atrazine resistance, 31- to 42-fold based on ED90 estimates, whereas NY-ORA and NJ-CMB populations remained susceptible. Target-site sequencing of the psbA gene revealed no mutations, indicating that resistance is conferred by a non–target site mechanism. Metabolic assays demonstrated that resistant populations retained 20% to 21% less intact atrazine 48 h posttreatment compared with the susceptible reference, suggesting enhanced metabolism likely mediated by glutathione S-transferase enzymes. All populations were susceptible to mesotrione, with the field rate of 105 g ai ha⁻1 providing ≥94% control. Tank mixtures of atrazine plus mesotrione applied postemergence provided near-complete control (≥97% biomass reduction relative to nontreated checks) across the tested populations, including those resistant to atrazine alone, which is consistent with synergistic interactions between PSII and HPPD inhibitors. This study documents two new cases of atrazine-resistant A. palmeri in New York and shows that resistance is mediated by enhanced metabolism, consistent with findings from other states. These results have important implications for northeastern corn (Zea mays L.) production, where atrazine remains foundational to weed management. The sustained efficacy of atrazine–mesotrione combinations offers an immediate management option, but integrated strategies incorporating multiple herbicide sites of action and cultural practices are critical to prevent further resistance evolution.

The academic training of professionals influences the evolution and future direction of scientific disciplines. However, the training background and demographic composition of weed science faculty have not been systematically characterized. To address this, we conducted an Internet-based survey of weed science faculty at universities in the United States of America that included the academic fields of the degrees these faculty had received, the institutions that granted these degrees, which U.S. states or countries (if outside the United States) the degrees came from, the current academic rank of each faculty member, whether the faculty held leadership positions at their universities, and the gender of each faculty member. We identified 223 faculty at 50 universities. They received their degrees from institutions in 24 countries and 39 U.S. states. Most of their BS degrees were in agronomy and crop science or plant science, physiology, and genetics, with a few weed science and ecology degrees. Weed science and ecology representation increased at the MS level and became the most common doctoral training area. A plurality of the faculty were professors (48.9%), followed by assistant professors (28.7%), associate professors (19.7%), lecturers (0.9%) and unidentified rank (1.8%). Men made up 82.5% of the faculty with women at 17.5%. Men also held more of the leadership positions (84.4%) than women (15.6%). These findings provide the first comprehensive overview of the weed science academic workforce of the United States and establish a baseline for evaluating future trends in training pathways, disciplinary identity, workforce diversity, and potential continental or international comparisons.

Weed-induced nutrient competition represents a major limitation on yield and quality in organic wheat (Triticum aestivum L.) cultivation. This study evaluated the effects of wide-range sowing on root-driven nutrient competition dynamics between wheat (‘Yongliang 4’) and weeds. A 2-yr experiment (2019 to 2020) in Bayannur, Inner Mongolia, compared three treatments: wide-range uniform sowing (W0), 7-cm wide-range sowing (W7), and conventional drilling sowing (CK). The study measured grain yield and protein content, root traits, and the dynamic changes in nutrient accumulation of organic wheat and field weeds, analyzing the nutrient competition levels and their responses to the different sowing methods. The 2-yr data demonstrated that both W0 and W7 treatments significantly enhanced grain yield in organic wheat compared with CK, with yield increments of 28.2% and 15.1%, respectively. Compared with CK, the W0 treatment significantly improved root system development and nutrient uptake. Throughout various growth stages (at 60, 85, and 100 d after sowing), the average root length, surface area, volume, and weight density within the 0- to 80-cm soil profile increased more than 13.8%, 24.5%, 14.1%, and 19.2%, respectively, under W0 treatment. Concurrently, nitrogen (N), phosphorus (P), and potassium (K) uptake in wheat plants under W0 treatment showed enhancements greater than 34.6%, 39.5%, and 39.6% compared with CK. In contrast to the enhanced nutrient uptake in wheat, both experimental treatments significantly suppressed weed nutrient uptake. The W0 treatment reduced N, P, and K uptake in weeds by 55.9%, 57.9%, and 51.9%, respectively, while the W7 treatment decreased these parameters by 40.1%, 39.8%, and 40.2%, respectively. The wide-range sowing pattern particularly enhanced the nutrient competitiveness of organic wheat, with this competitive advantage becoming more pronounced during later growth stages. Statistical analyses revealed significant positive correlations between grain yield/protein content and root morphological parameters, as well as plant nutrient uptake. Conversely, significant negative correlations were observed between wheat productivity parameters and weed nutrient uptake, suggesting effective resource competition by the wheat plants under modified cultivation practices. In conclusion, wide-range sowing cultivation improves the nutrient competition ability of organic wheat through enhancing root traits, thereby suppressing weed access to nutrient resources and ultimately increasing both yield and grain quality of organic wheat.

Laser weed control is an emerging nonchemical technology made feasible by recent advances in artificial intelligence and automation. This research evaluated the response of four turf and weed species to varying levels and patterns of laser intensity to determine practical applications of laser weeding in turfgrass systems. Field experiments were conducted from July 2024 to March 2025 on research fairways in Blacksburg, VA, using a 10-W diode laser in spiral patterns with varying pattern-averaged energy densities (PAED). Two studies were implemented: one evaluated increasing energy intensity; the other assessed combinations of line spacing, PAED, and number of passes in a factorial design. Line spacing significantly influenced weed control efficacy, with 4-mm spacing improving green cover reduction by up to 10% over denser patterns at the same PAED. Bermudagrass [Cynodon dactylon (L.) Pers.] recovered fully within 24 d posttreatment, while creeping bentgrass (Agrostis stolonifera L.) showed prolonged injury at higher intensities and wider spacings. These results demonstrate that laser weeding is feasible in turfgrass systems, especially with optimized energy and pattern configurations, and highlight the need for pattern customization to balance weed control with turfgrass safety.

Isoproturon is widely used to control Italian ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot] in wheat (Triticum aestivum L.) fields across China. Here, we identified a highly resistant population (HR) from 87 populations collected from wheat fields; it showed 4.6-fold resistance to isoproturon compared with a susceptible control (HS). DNA sequencing of the full-length psbA gene revealed no sequence differences between HR and HS plants. However, psbA expression in the HR population was significantly higher than in the HS population, both before and after isoproturon application. Transgenic assays confirmed that psbA gene overexpression in rice (Oryza sativa L.) plants confers resistance to photosystem II (PSII) inhibitors, including isoproturon. Under isoproturon application, the HR population also demonstrated elevated antioxidant enzyme activities and maintained higher chlorophyll and carotenoid levels. Furthermore, the HR population remained susceptible to pyroxsulam and pinoxaden, suggesting that these herbicides are practical alternatives for control. These findings indicate that psbA gene overexpression contributes to isoproturon resistance in L. perenne ssp. multiflorum, likely through the overproduction of the D1 protein to mitigate herbicide-induced PSII dysfunction. Our study provides the first confirmation and mechanistic explanation of isoproturon resistance in L. perenne ssp. multiflorum, revealing psbA gene overexpression as the key driver.

Understanding how reduced-tillage practices influence weed community assembly is critical for designing ecologically sustainable organic cropping systems. We evaluated the effects on emerged weed biomass and seedbank dynamics of three cropping systems combining contrasting tillage regimes and cover crop strategies within an organic corn (Zea mays L.)–soybean [Glycine max (L.) Merr.]–spelt (Triticum spelta L.) rotation. Drawing from community assembly theory, we tested the roles of abiotic (soil disturbance), biotic (crop competition), and legacy filters (crop entry and cover crop history) across crop phases and spatial positions (interrow vs. intrarow). Our results show that weed community composition was shaped more by crop identity, spatial heterogeneity, and legacy effects than by tillage intensity alone. In soybean, the system with the lowest disturbance and a 14-mo undisturbed red clover (Trifolium pratense L.) cover crop legacy (IT/C–NT/S) selected for low-diversity communities dominated by giant foxtail (Setaria faberi Herrm.), particularly in intrarow zones. In contrast, in corn, spatial location explained more variation than cropping system, with intrarow communities again consistently dominated by S. faberi. Seedbank composition did not differ among systems but was significantly more diverse in the entry that had spelt in the last year of the rotation compared with the entry that had it in the first year, suggesting a strong filtering effect of the winter crop. Indicator species analysis further confirmed system-level filtering, with S. faberi strongly associated with low-disturbance soybean systems. These findings underscore the importance of considering within-field spatial heterogeneity and rotational legacy when designing organic weed management strategies and support the use of ecological filtering frameworks to understand weed community dynamics in complex organic systems.

Clonality plays an important role in the proliferation of invasive species and can facilitate invasive success by reducing reliance on sexual reproduction and promoting spread of genetically identical individuals. Clonal invasions are advantageous for biological control strategies, as biological control agents may have a uniform, damaging response to invasive populations with low genetic diversity. Agents sourced in the native range, that are locally adapted to the same plant genotype that is invasive, may cause this response. Understanding the population genetics and invasion history of a species in the novel range is paramount to ensure effective biological control agents are introduced. Here we investigated the population genetics of pickerelweed (Pontederia cordata L.), a tristylous invasive macrophyte native to North and South America that is causing detrimental impacts in South Africa (SA). SA populations all have only one of three tristylous forms and produce no seeds. Inter simple sequence repeats (ISSR) of P. cordata leaf samples from SA and from parts of the native range in the United States were used to determine population structure and potential source populations. Pontederia cordata has low genetic diversity within and among invasive populations in SA compared with native populations. This suggests no sexual reproduction and limited gene flow in SA and only one introductory event. Invasive populations shared the closest genetic similarity with native samples from Virginia, USA, and although large parts of the indigenous distribution were not sampled, this close match suggests that the site may be a suitable area to source potential biological control agents. However, genetic sampling in other native areas should also be considered to confidently determine the origin of SA populations. This study corroborates other global findings of highly successful invasive species utilizing clonality and, consequently, resulting in invasive genotypes with low diversity.

Johnsongrass [Sorghum halepense (L.) Pers.] is a highly invasive, persistent, and problematic perennial weed in Australian cropping systems; however, its germination ecology has largely been inferred from studies conducted outside eastern Australia, where environmental conditions differ markedly. This limits accurate prediction of emergence timing and optimization of management strategies. The objectives of this study were to characterize seed dormancy mechanisms and to quantify the germination and emergence response of two populations of S. halepense from central Queensland to temperature, light, salinity, osmotic stress, and burial depth under controlled conditions. Seeds from both populations exhibited strong primary dormancy, which was partially alleviated by sodium hypochlorite immersion and more effectively by mechanical scarification using sandpaper, indicating that seed coat–related dormancy is the principal barrier to germination. Temperature significantly influenced germination, with no germination at 15/5 C and high germination (>90%) at 25/15 C to 35/25 C under both light/dark and dark conditions, demonstrating that warm temperatures largely override light requirements. Germination declined steadily with increasing sodium chloride (NaCl) concentrations, and the NaCl concentration required to reduce maximum germination by 50% was approximately 173 mM. Moderate water stress −0.2 to −0.4 MPa produced less germination in comparison to the control, while −0.8 MPa greatly inhibited germination (11%). Emergence was highest from shallow burial depths of 1 to 4 cm and declined sharply beyond 8 cm. These results demonstrate that S. halepense recruitment occurs in a range of environmental conditions; however, environmental stresses or deep soil burial may help manage this weed. This study provides regionally relevant information to enhance emergence prediction and inform integrated weed management strategies in eastern Australian cropping systems.

Glufosinate-ammonium (GA) has been widely used in U.S. Midwest fields, and in recent years a growing number of failures to control waterhemp [Amaranthus tuberculatus (Moq.) Sauer] have raised concerns about the evolution of resistance. The goal of this study was to investigate four cases of suspected resistance to GA in A. tuberculatus from Illinois using greenhouse, field, and transcriptomics studies. Greenhouse dose–response experiments revealed resistance ratios ranging from 2.2-to 3.4-fold based on survival and 1.3-to 2.8-fold based on biomass relative to a susceptible population. A subsequent field study where one of the populations originated confirmed that 20% of treated plants survived the labeled GA field recommended rate. Screening with other herbicide site-of-action groups revealed that most populations showed reduced sensitivity to atrazine, glyphosate, and imazethapyr, surviving up to 3× the field recommended rates, and to a lesser extent, lactofen and fomesafen. Transcriptomic analysis of plants surviving GA revealed no resistance-associated mutations or differential transcript abundance in the plastidic and cytosolic isoforms of glutamine synthetase. Among the four suspected resistant populations, there were 182 genes differentially expressed relative to two susceptible populations. Different sets of genes were differentially expressed among the populations studied, with only one gene (upregulated relative to two susceptible populations) shared among all four. Many of the differentially expressed genes, including cytochrome P450s, glutathione S-transferases, glycosyltransferases, transporters, and transcriptional regulators, are commonly associated with metabolic resistance. Gene ontology enrichment analyses indicated significant overrepresentation of stress response, defense regulation, and secondary metabolism categories across the populations. Together, these findings provide evidence for the evolution of GA resistance in populations of A. tuberculatus in Illinois. While more in-depth studies are needed to fully characterize the underlying mechanisms, the consistent differential expression of metabolism-related genes and no indication of target-site mechanisms point to a potential metabolic basis for resistance.