Search Results (260)

In this study, we evaluated the spatial variability in droplet deposition in herbicide applications using a remotely piloted aircraft (RPA) in pasture areas. The investigation was conducted in a square grid (50.0 m × 50.0 m), with 121 sampling points, at two operational flight heights (3.0 and 4.0 m). Droplet deposition was quantified using the fluorescent dye rhodamine B, and the droplet spectrum was characterised using water-sensitive paper tags. Geostatistical analysis was implemented to characterise spatial dependence, complemented by multivariate statistical analysis. Droplet deposition ranged from 1.01 to 9.02 and 1.10–6.10 μL cm⁻² at 3.0 and 4.0 m flight heights, respectively, with the coefficients of variation between 19.72 and 23.06% for droplet spectrum parameters. All droplet spectrum parameters exhibited a moderate to strong spatial dependence (relative nugget effect ≤75%) and a predominance of adjustment to the exponential model, with spatial dependence indices ranging from 12.55 to 47.49% between the two flight heights. Significant positive correlations were observed between droplet deposition and droplet spectrum parameters (r = 0.60–0.79 at 3.0 m; r = 0.37–0.66 at 4.0 m), with the correlation magnitude decreasing as the operational flight height increased. Cross-validation indices demonstrated acceptable accuracy in spatial prediction, with a mean estimation error ranging from −0.030 to 0.044 and a root mean square error ranging from 0.81 to 2.25 across parameters and flight heights. Principal component analysis explained 99.14 and 85.72% of the total variation at 3.0 and 4.0 m flight heights, respectively. The methodological integration of geostatistics and multivariate statistics provides a comprehensive understanding of the spatial variability in droplet deposition, with relevant implications for the optimisation of phytosanitary applications performed using RPAs. Full article

There is growing interest in the use of herbicide for the silvicultural practice of tree thinning (i.e., chemical thinning or e-thinning) in New Zealand. Potential benefits of this approach include improved stability of the standing crop in high winds, and safer and lower-cost operations, particularly in steep or remote terrain. As uptake grows, tools for monitoring treatment effectiveness, particularly during the early stages of stress, will become increasingly important. This study evaluated the use of UAV-based multispectral and hyperspectral imagery to detect early herbicide-induced stress in a nine-year-old radiata pine (Pinus radiata D. Don) plantation, based on temporal changes in crown spectral signatures following treatment with metsulfuron-methyl. A staggered-treatment design was used, in which herbicide was applied to a subset of trees in six blocks over several weeks. This staggered design allowed a single UAV acquisition to capture imagery of trees at varying stages of herbicide response, with treated trees ranging from 13 to 47 days after treatment (DAT). Visual canopy assessments were carried out to validate the onset of visible symptoms. Spectral changes either preceded or coincided with the development of significant visible canopy symptoms, which started at 25 DAT. Classification models developed using narrow band hyperspectral indices (NBHI) allowed robust discrimination of treated and non-treated trees as early as 13 DAT (F1 score = 0.73), with stronger results observed at 18 DAT (F1 score = 0.78). Models that used multispectral indices were able to classify treatments with a similar accuracy from 18 DAT (F1 score = 0.78). Across both sensors, pigment-sensitive indices, particularly variants of the Photochemical Reflectance Index, consistently featured among the top predictors at all time points. These findings address a key knowledge gap by demonstrating practical, remote sensing-based solutions for monitoring and characterising herbicide-induced stress in field-grown radiata pine. The 13-to-18 DAT early detection window provides an operational baseline and a target for future research seeking to refine UAV-based detection of chemical thinning. Full article

Some herbicides, such as saflufenacil, can persist as residues in sprayer tanks even after cleaning, causing phytotoxicity in sensitive crops. This study aimed to simulate potential injury caused by saflufenacil residues, applied alone or combined with glyphosate, on soybean. The field experiment was conducted using a randomized complete block design with four replicates. The treatments included glyphosate (1440 g ha⁻¹), eight saflufenacil doses ranging from 1.09 to 70.00 g ha⁻¹, each tested alone or combined with glyphosate, and a weed-free control, totaling 18 treatments. Phytotoxicity was assessed at 7, 14, 21, 28, and 35 days after treatment (DAT). Physiological variables were measured at 21 DAT, and grain yield components were evaluated at harvest. Saflufenacil caused increasing phytotoxicity at doses exceeding 4.38 g ha⁻¹ when applied alone and above 2.17 g ha⁻¹ when combined with glyphosate. The highest doses negatively affected soybean physiology and grain yield components. Soybean tolerated up to 2.17 g ha⁻¹ saflufenacil alone and up to 1.09 g ha⁻¹ combined with glyphosate without significant yield loss. These results highlight the importance of thorough and correct cleaning of the sprayer tank and suggest limit residue levels that avoid crop damage, helping to prevent unexpected damage to soybean in crop rotations. Full article

A bioassay study was conducted to determine the differences in the sensitivity of selected crops to simulated clomazone residues (nine concentrations were used ranging from 5.625 to 1440 μg a.i./kg soil). White mustard was the most susceptible as measured by shoot fresh weight (SFW) and shoot dry weight (SDW) inhibition, with EC₅₀ values of 94.6 and 128.2 μg a.i./kg soil, respectively. Regarding the EC₅₀ values for the inhibition of pigment content (carotenoids, chlorophyll a and chlorophyll b), sugar beet and white mustard showed a high sensitivity, as the EC₅₀ values for all three pigments were in the range of 45.8–47.4 and 57.5–63.3 μg a.i./kg soil, respectively. However, as the SFW and SDW of sugar beet were only reduced at the three highest clomazone concentrations applied, white mustard proved to be the most sensitive crop. Wheat was less sensitive (EC₅₀ = 214.4–243.8 μg a.i./kg soil, for all three pigments), while sunflower and maize were the least sensitive (EC₅₀ = 359.7–417.5 and 456.1–535.8 μg a.i./kg soil, respectively). Field trials were conducted for two years in the Srem region to study the dynamics of clomazone degradation in sandy loam soil. Clomazone was applied pre-plant incorporated (PPI) and post-emergence (POST-EM) in three doses: 480, 720 and 960 g a.i./ha. Soil samples were taken at regular intervals from the day of herbicide application until one year after application and residue concentrations were determined using the white mustard bioassay (based on the measurement of carotenoid content inhibition). The application rate had no consistent effect on the persistence of clomazone. Slower degradation was observed in the PPI treatment than in the POST-EM treatment (8.5 and 15 days longer average half-lives in the first and second year, respectively). Persistence was affected by lower rainfall, resulting in a longer half-life in the second year (12 days on average). Herbicide residues caused no visible injury to white mustard one year after application, while the reduction in carotenoid content ranged from 0.37 to 22.89%, indicating that no injury can occur to any of the tested crops one year after application of clomazone in sandy loam soil. Full article

Glufosinate-ammonium (GLA) is a broad-spectrum herbicide widely used for weed control. However, its potential toxic effects on non-target aquatic organisms, especially in freshwater ecosystems, are of growing concern. This study investigates the toxic effects of GLA on Biomphalaria glabrata, a freshwater snail highly sensitive to environmental pollutants and commonly used as a model organism in toxicological studies. Acute toxicity tests revealed that the 96-h LC50 of GLA for adult snails was 3.77 mg/L, indicating moderate toxicity, while the LC50 for embryos was 0.01576 mg/L, indicating extremely high toxicity. Chronic exposure experiments further showed that at high concentrations (0.5 mg/L), the shell diameter and body weight of the snails not only failed to increase but also decreased, and they ceased to lay eggs. Moreover, their hepatopancreas and gonads suffered significant damage. Even at an environmentally relevant concentration of 0.05 mg/L, the body length, body weight, and reproductive capacity of the snails were inhibited, and damage to the hepatopancreas and gonads was observed. These findings provide important data for assessing the potential risks of GLA to aquatic ecosystems and offer a scientific basis for formulating environmental protection policies and optimizing herbicide usage standards. Full article

Glyphosate (GLYP) is an effective and low-cost broad-spectrum herbicide. However, this herbicide and its primary degradation product, aminomethylphosphonic acid (AMPA), have been linked with adverse human health effects. The global use of glyphosate has significantly increased in recent years, resulting in more direct and indirect human exposure. In this context, GLYP and AMPA are often detected in fresh and processed foods for adults and infants, as well as in drinking water worldwide. Diverse extraction and quantification methods for GLYP and AMPA from foods have been developed. Solid-phase extraction and QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) are the most frequently employed cleanup strategies, while LC-MS/MS is one of the most sensitive and selective techniques for detecting GLYP and AMPA in food products. Although most studies show that GLYP and AMPA concentrations in foods remain within established maximum residue limits, occasionally they exceed legal limits. Thus, the widespread presence of GLYP and AMPA in foodstuffs is a public concern that may lead to consumers exceeding the acceptable daily intake due to prolonged dietary exposure, even if levels remain within thresholds. Therefore, this review explores the different approaches and techniques used in the extraction, detection, and quantification of GLYP and AMPA in foods. 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

Mesotrione is a triketone herbicide widely used for weed control in maize (Zea mays L.). In a bioassay conducted under controlled conditions, the simulated residual effects of mesotrione on leafy vegetables, including chard, lettuce, spinach, and endive were evaluated. The herbicide was applied at nine concentrations (0–240 µg a.i./kg soil), with the highest corresponding to the recommended field application rate. Nonlinear regression analysis was used to describe the relationship between morphological (shoot fresh weight) and physiological (pigment content) parameters as a function of herbicide dose. Shoot fresh weight was a more sensitive parameter than pigment content with mean EC₅₀ ± SE values of 23.9 ± 3.5 (chard), 34.3 ± 7.7 (lettuce), 13.2 ± 2.4 (spinach), and 990.3 ± 3921.5 (endive) µg a.i./kg soil, indicating that spinach is the most sensitive and endive the most tolerant species. A mesotrione residue level equivalent to EC₂₀ for shoot fresh weight corresponds to approximately 2, 4, 6, and 29% of the recommended application rate of mesotrione at which spinach, chard, lettuce, and endive (respectively) can be safely sown. Therefore, spinach, chard, and lettuce are not suitable substitutes for maize when the latter fails and should not be sown after silage maize. In such cases, only endive appears to be a viable alternative without the risk of crop injury. Full article

Amaranthus palmeri is a highly problematic agricultural weed due to its rapid growth, high seed production, and strong tendency to develop herbicide resistance. In Spain, the initial colonization of A. palmeri began in 2007, when populations were detected at various locations in the province of Lleida (Catalonia). Since then, new infestations have been reported in other regions of the country, primarily infesting maize fields. Although resistance to glyphosate or to acetolactate synthase (ALS) inhibitors has been documented in several populations from Catalonia and Extremadura, little is known about the resistance profile of populations from Aragon. The main objective of this study was to characterize the putative resistance of five populations from Aragon to 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibitors (glyphosate) and ALS inhibitors (nicosulfuron and imazamox). Sensitivity to both mechanisms of action was measured by root growth in vertical plates and shikimate accumulation for glyphosate. Target-site resistance was evaluated by analyzing EPSPS and ALS gene copy numbers and ALS gene mutations. The populations showed high variability, with no multiple resistance detected. The Bujaraloz population showed moderate resistance to glyphosate due to EPSPS gene amplification. In three populations, mutations in the ALS gene conferring resistance were detected. The Trp574Leu mutation was detected in approximately half of the individuals from the Albelda, Tamarite de Litera, and Caspe populations. In the latter, the Pro197Thr mutation was also present. This study reveals significant genetic variability within each population and provides evidence for the spread of herbicide resistance across different regions of Spain. Full article

Environmental concerns regarding synthetic herbicides have sparked interest in plant-derived bioactive compounds as eco-friendly alternatives. This study investigated the cellular targets of sweet flag essential oil (Acorus calamus L., SEO at IC₅₀ concentration) in root meristem cells of Fabaceae (Vicia faba, Lupinus luteus) and Brassicaceae (Brassica napus, Arabidopsis thaliana), focusing on reactive oxygen species (ROS) accumulation (DAB, NBT staining), DNA replication dynamics (EdU labeling), and genome integrity (γ-H2AX immunocytochemistry, TUNEL assay, and DNA electrophoresis). SEO induced oxidative stress (200–250% of control depending on the species) and replication stress, causing DNA double-strand breaks in 50% of proliferating cells, confirmed by γ-H2AX/TUNEL. Consequently, cells were prolonged in the G₁ phase, replication activity dropped to 70% of control in Fabaceae and 80% in Brassicaceae, and EdU incorporation intensity decreased to 80% and 70% of control, respectively. An increased proportion of cells replicating heterochromatin indicated slowed S-phase progression. Despite genotoxic effects, SEO did not trigger endoreplication, apoptotic DNA fragmentation, or extensive cell death. All species exhibited a uniform stress response, although sensitivity varied, which previously enabled the establishment of selective SEO doses between Fabaceae and Brassicaceae. These findings suggest that SEO exerts phytotoxicity by disrupting S-phase progression, supporting its potential as a selective bioherbicide. Full article

Tomato is a major crop, and efforts are ongoing to enhance its resilience to biotic and abiotic stresses. Weed management remains a key challenge, prompting the search for sustainable alternatives to reduce the impact of excessive herbicide use. Biochar is a promising alternative, as it enriches the soil, improves its water retention capacity, promotes its regeneration and increased fertility, delays nutrient leaching, and improves fertilizer use efficiency. This study aimed to investigate the efficiency of biochar use in mitigating stress caused by different herbicides. Two different biochar materials, Douglas fir and rice husk, were used. Tomato seeds were sown in pots and arranged in a randomized design. At the 4V stage (28 days after sowing), the herbicides S-metolachlor, metribuzin, and halosulfuron were applied. Plant length, injury, antioxidant enzyme activity, ascorbate peroxidase (APX), catalase (CAT), guaiacol peroxidase (GPOD), glutathione reductase (GR), and hydrogen peroxide content (H₂O₂) were assessed 7 and 14 days after herbicide application. Plants treated with biochar and submitted to herbicide treatments showed significantly higher growth parameters and fewer injuries when compared to plants treated with herbicides without biochar. The antioxidant response of the plants followed the same trend; smaller plants with more injuries showed greater H₂O₂ accumulation and significantly higher antioxidant enzyme activity. These findings highlight the protective effect of biochar, particularly Douglas fir biochar, as it effectively mitigated herbicide-induced oxidative stress and helped maintain plant growth and structural integrity under treatment conditions. 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

Glyphosate is a broad-spectrum herbicide widely used. After years of extensive usage, many weed species have developed resistance due to both target-site (TSR) and non-target-site resistance mechanisms (NTSRs). Alopecurus myosuroides is a competitive weed species. Greenhouse monitoring trials in Germany have revealed reduced glyphosate efficacy against some populations of Alopecurus myosuroides. In a foregoing dose–response study, individual plants from four out of six tested populations survived full (1800 g a.i. ha⁻¹) or double (3600 g a.i. ha⁻¹) glyphosate dose rates permitted, suggesting the presence of tolerant biotypes with yet unknown resistance mechanisms. Our aim was to investigate the absorption and translocation patterns of glyphosate in these biotypes. The plants were first treated with ¹⁴C-glyphosate, and ¹⁴C-glyphosate absorption and translocation were subsequently visualized by phosphorimaging and finally quantified by liquid scintillation counting. The results showed significant differences in the distribution of glyphosate in different plant organs, with significantly more being translocated out of the treated leaf in glyphosate-resistant compared to sensitive (S-) biotypes. The study’s findings are partly in contrast to previous studies that have found reduced translocation. Our study demonstrates the complex nature of glyphosate resistance and suggests further experiments to finally elucidate the underlying resistance mechanisms in the biotypes of the Alopecurus myosuroides studied. Full article

In recent years, maximum residue limit (MRL) standards regulated by governments have become increasingly stringent. MRL standards aim to protect human health and environmental sustainability by setting maximum allowable residue concentrations for chemical substances in imported products. In November 2020, the European Union published EU Regulation 2020/1085, imposing stricter MRL standards on imported agricultural products. As standard-setting leaders implement more restrictive MRLs and export-oriented countries adjust their chemical practices to align with these standards, it is essential to examine the emerging trade patterns associated with MRLs and exports. This paper investigates the impact of maximum residue limits (MRLs) on China’s agricultural exports, using disaggregated product-level data (HS eight-digit) for 237 products across 43 importing countries from 2006 to 2021. The results show that a 10% more stringent MRL at the mean in the previous year leads to a 6.6% decrease in the current-year export values of China’s agricultural products. Stricter MRLs for insecticides significantly reduce China’s agricultural exports, while MRLs for fungicides and herbicides have no significant effect. Additionally, I analyze the top 10 most frequently notified chemical substances in goods from China, as reported by the European Commission’s Rapid Alert System for Food and Feed (RASFF) over 2020–2024. More stringent MRLs for Chlorpyrifos, Diafenthiuron, and Carbendazim significantly impede China’s agricultural exports to the European Union. Conversely, China’s agricultural exports to USMCA, ASEAN, and BRI member countries are sensitive to more restrictive MRLs for Diafenthiuron, while benefiting from tougher MRLs for Tolfenpyrad, Dinotefuran, and Imidacloprid. The impacts of MRLs on the extensive and intensive margins of exports suggest that more restrictive MRLs do not significantly affect the probability of exporting, but they reduce export values conditional on the export decisions. The findings suggest that tightening MRL standards by importing countries do not necessarily impede agricultural trade; in some cases, they facilitate China’s agricultural exports to these markets. This study provides policymakers with a comprehensive analysis to formulate strategies for enhancing agricultural exports and highlights the role of food safety standards in sustainable development. Full article

This study presents the evaluation of tools for weed analysis and management to support agroecological practices in organic farming, emphasizing agriculture digitalization, and remote sensing. The main aim was to provide techniques for monitoring and predicting weed spread using multispectral satellite and drone data, without the use of chemical inputs. Key findings indicate that VV and VH channels of Sentinel-1 and B2, B3, B4, and B8 channels of Sentinel-2 are not different regarding tillage, herbicide use, or sowing density. However, RE and NIR channels of drone detected significant variations and proved effectiveness for weediness monitoring. The NIR channel is sensitive to agrotechnical factors such as cultivation type, making it valuable for field monitoring. Correlation and regression analyses revealed that B2, B3, B8 channels of Sentinel-2, and RE and NIR drone channels are the most reliable for predicting weed levels. Conversely, Sentinel-1 showed limited predictive utility. Random effect models confirmed that Sentinel-2 and drone channels can accurately account for site characteristics and timing of weed proliferation. Taken together, these tools provide effective organic weed monitoring systems, enabling rapid identification of problem areas and adjustments in agronomic practices. Full article