Search Results (58)

Transboundary basins in arid and semi-arid regions are increasingly stressed by groundwater depletion, drought, and competing upstream water-management policies. Quantifying surface–groundwater interactions in such systems remains challenging due to sparse hydroclimatic observations. This study develops and applies a fully coupled SWAT–MODFLOW model to the Tigris–Euphrates River Basin (TERB; ~900,000 km²), the largest transboundary basin in the Middle East, to evaluate spatiotemporal stream–aquifer interactions and basin-scale water balance. The model integrates SWAT 2012 with MODFLOW-NWT at daily and monthly time steps and was calibrated and validated against monthly streamflow records from 23 gauges and groundwater levels from four wells over 1981–2002, with a 1976–1980 warm-up period. A multi-stage calibration strategy was adopted, including standalone SWAT calibration using SUFI-2, standalone MODFLOW calibration using PEST, and subsequent coupled refinement. Model performance was satisfactory, with Nash–Sutcliffe efficiencies exceeding 0.5 for streamflow and strong agreement between simulated and observed groundwater levels (R² = 0.92). Basin-integrated total water storage anomalies showed reasonable agreement with GRACE-derived estimates for 2002–2013 (R² ≈ 0.72). The basin-averaged net stream–aquifer exchange was estimated at −7.08 × 10⁶ m³ yr⁻¹, indicating net river leakage to aquifers, with a marked intensification after 1987 consistent with major upstream reservoir developments. Recharge patterns were highest over permeable foothill formations and lowest over consolidated northern highlands. The integrated use of streamflow, groundwater, and GRACE observations within a fully coupled framework provides a transferable approach for water-resources assessment in data-scarce transboundary basins. Full article

The Moroccan locust (Dociostaurus maroccanus) is one of the most economically significant locust species in the Caucasus and Central Asia. In the past, the Mediterranean region also experienced severe damage to crops and pastures, until widespread grassland conversion to cropland began in the second half of the 20th century. However, climate change, environmental shifts, land-use changes, cropland abandonment, and overgrazing are likely to alter the spatial distribution and outbreak patterns of this pest. Understanding potential changes and geographic shifts is essential for proactive pest management, including effective monitoring and control strategies. In this study, we apply Ecological Niche Modelling (ENM) using 12 machine learning algorithms, historical survey data covering the species’ full distribution range, and relevant abiotic variables to identify the most suitable areas for potential mass breeding during 1991–2020 and the near future (2021–2040), based on the “middle-of-the-road” Shared Socioeconomic Pathway (SSP2-4.5) scenario. Our results indicate significant regional shifts. Notably, breeding suitability is projected to increase in parts of Greece, Turkey, Armenia, Georgia, Kyrgyzstan, and Tajikistan. In contrast, countries such as Turkmenistan, Afghanistan, Pakistan, and Spain are likely to experience a decline in optimal breeding areas. The forecast results support field observations of a geographical shift northward and toward higher altitudes. Additionally, higher temperatures in suitable areas suggest more drought-like conditions, which typically promote locust population explosions and outbreaks. If left unaddressed, such outbreaks can cause severe economic damage to affected regions. Full article

Clarifying migration pathways and the source area–destination relationships of the domestic and foreign beet webworm Loxostege sticticalis (Linnaeus) populations, as well as understanding the meteorological mechanisms shaping these processes, is pivotal for remote, accurate, and location-specific pest early warning and forecasting. Based on light trap data from northern China and field survey data from Mongolia in 2022, we simulated the migration trajectories, source regions, and primary landing areas of L. sticticalis by using the HYSPLIT model and analyzed the synoptic systems, processes and conditions during its migration. The results indicate the frequent exchange of L. sticticalis populations between China and Mongolia in 2022. The L. sticticalis migrants initiating their flights from Mongolia primarily undertook a southeastward migration pathway, supplemented by eastward ‘cyclonic’ and southwestward paths. The main landing areas were located in North China and Northeast China, with migration events potentially extending to the Shandong, Heilongjiang, and Xinjiang provinces. Populations originating from North China exhibited a capacity for migrating into Northeast China and Mongolia through 1–5 consecutive nights of flight. During this period, the Northeast China Cold Vortex (NCCV) and the Mongolian Cyclone alternately regulated the synoptic circulation pattern governing the migration of L. sticticalis. The spatiotemporal distributions and intensities of these systems were key determinants of the transboundary migration routes and distances of L. sticticalis. The NCCV dominated, and the precipitation and downdrafts it induced were crucial for the massive landing of L. sticticalis in northern China. Full article

Cirsium vulgare (Asteraceae) is a newly emerged invasive species in Yunnan Province, China, and its phytotoxic potential has not yet been studied. This study was conducted to explore potential allelopathic effects of C. vulgare and to identify its flavonoid and phenolic acid compounds. Four aqueous extracts (roots, stems, leaves, and flower/fruit heads) of C. vulgare exhibited high inhibitory activity against the germination and seedling growth of Bidens pilosa and Digitaria sanguinalis. The inhibition rates of germination rate, germination index, root length, shoot length, and biomass of both species increased significantly with increasing concentrations, with B. pilosa being more inhibited than D. sanguinalis. Extracts from leaves and flower/fruit heads yielded the strongest inhibition, followed by stem extracts, with the lowest impact from root extracts. Flavonoids (65.41%) and phenolic acids (23.1%) collectively comprised 88.51% of all identified compounds. Thirty-eight flavonoid compounds and thirty phenolic acid compounds were selected for further analysis, representing 53.97% and 71.91% of the total content of flavonoids and phenolic acids, respectively. Many of the flavonoids and phenolic acids identified have been previously reported as known allelochemicals with possible allelopathic effects. This was the first study to show that the allelopathic potential of C. vulgare may aid its invasion and expansion. Full article

Background: Peste des petits ruminants (PPR) is an acute or subacute contagious trans-boundary viral disease causing high morbidity and mortality in domestic and wild small ruminants. The national UAE-PPR control and eradication plan follows the PPR Global Control and Eradication Strategy (PPR GCES) and relies on the annual mass vaccination of small ruminants to eradicate the disease from the country by 2030. Despite the immunization effort against PPR, the vaccination coverage reached 65% at maximum, which necessitates conducting a post-vaccination evaluation (PVE) study at the national level. Methods: Using multistage random sampling to assess the PPR vaccine and vaccination effectiveness, protocol (2) of the PPR GCES, using two serosurveys; serosurvey (1) (pre-vaccination) at day 0 before vaccination, to assess the primary PPR serological investigation, and serosurvey (2) at (30–90) days post-PPR vaccination, to evaluate the immune response, were carried out from September to December 2024 across the seven Emirates of the UAE. The nucleoprotein-based competitive enzyme-linked immunosorbent assay (c-ELISA) was used to detect PPR antibodies in a total of 1592 and 1589 sera samples collected, respectively, before and after vaccination from different (n = 163) sheep and goats holdings (epi-unit) distributed in the different Emirates of the UAE. Results: In serosurvey (1). prior to vaccination, out of the total 1592 samples tested (839 goats and 753 sheep), 833 animals (52.32%) were found to be seropositive for PPR antibodies. In contrast, in serosurvey (2), after vaccination, 1490 (93.77%) animals were found to be seropositive out of the total 1589 small ruminants (825 goats and 764 sheep) tested by c-ELISA. A statistically significant increase (41.45%) in the overall seroprevalence from (52.32%) pre-vaccination to (93.77%) post-vaccination was observed. Post-vaccination, 93.87% (n = 153) of the vaccinated epi-units achieved more than 70% seroprevalence compared to 43.56% (n = 71) before vaccination. Prediction analysis showed that all the seven UAE Emirates require 1.2 years maximum to reach 100% immune-protection levels. Conclusions: An efficient PPR vaccine was used to immunize small ruminants in the UAE. Higher (89.47–100%) post-vaccination herd immunity than the threshold recommended by the PPR GCES (>80% immunity) was attained, which can efficiently break the spread of PPRV within the UAE. To enhance the eradication of PPR I the UAE, conducting mass vaccination campaigns targeting over the (95%) immunization coverage of eligible animals for the next three years is recommended to attain the requested sustained (>80%) immunity at the animals holding level. Full article

Acmella radicans (Jacquin) R.K.Jansen is an annual herb native to Central America. In China, it is becoming increasingly invasive and often co-occurs with the native congener A. paniculata (Wall. ex DC.) R.K.Jansen in some habitats. In order to understand the invasion mechanism of A. radicans, we investigated the growth parameters of both the invasive A. radicans and the native congener, A. paniculata, under different light conditions (5%, 25%, 50%, 75%, and 100% of light availability) using potted plants in a glasshouse. Light level, plant species, and their interaction were significant, with plant species generally having a greater effect than light level. Acmella radicans and A. paniculata showed great phenotypic plasticity to various light intensities and had a similar trend with increased shade. The plasticity indices of all parameters of A. radicans, except for branch length and inflorescence number, were greater than those of A. paniculata under the same light intensity. The physiological parameters for A. radicans under both favorable (high light intensity) and unfavorable (low light intensity) conditions showed less inhibition than those of A. paniculata. All these responses indicated that A. radicans had greater phenotypic plasticity and higher adaptability to low light, which may contribute to its invasion success. Full article

Spodoptera frugiperda is a major transboundary migratory pest under global alert by the Food and Agriculture Organization (FAO) of the United Nations. The accurate identification and counting of trapped adults in the field are key technologies for achieving quantitative monitoring and precision pest control. However, precise recognition is challenged by issues such as scale loss and the presence of mixed insect species in trapping images. To address this, we constructed a field image dataset of trapped Spodoptera frugiperda adults and proposed an improved YOLOv5s-based detection method. The dataset was collected over a two-year sex pheromone monitoring campaign in eastern–central Yunnan, China, comprising 9550 labeled insects across six categories, and was split into training, validation, and test sets in an 8:1:1 ratio. In this study, YOLOv7, YOLOv8, Mask R-CNN, and DETR were selected as comparative baselines to evaluate the recognition of images containing Spodoptera frugiperda adults and other insect species. However, the complex backgrounds introduced by field trap photography adversely affected classification performance, resulting in a relatively modest average accuracy. Considering the additional requirement for model lightweighting, we further enhanced the YOLOv5s architecture by integrating Mosaic data augmentation and an adaptive anchor box strategy. Additionally, three attention mechanisms—SENet, CBAM, and Coordinate Attention (CA)—were embedded into the backbone to build a multidimensional attention comparison framework, demonstrating CBAM’s superiority under complex backgrounds. Ultimately, the CBAM-YOLOv5 model achieved 97.8% mAP@0.5 for Spodoptera frugiperda identification, with recognition accuracy for other insect species no less than 72.4%. Based on the optimized model, we developed an intelligent recognition system capable of image acquisition, identification, and counting, offering a high-precision algorithmic solution for smart trapping devices. Full article

Diaphorina citri is the primary global vector of “Candidatus Liberibacter asiaticus”, the bacterium responsible for Huanglongbing. Syntaxin-1A (Syx1A), a member of the Qa-SNARE family, is essential for vesicle fusion and signal transduction, though its function in hemipteran insects remains poorly understood. This study presents the first comprehensive analysis of Syx1A expression in D. citri. Transcripts were detected across all life stages, with peak expression in the salivary glands. RNAi silencing of Syx1A reduced mRNA levels by 39.0% in nymphs and 58.0% in adults, resulting in 58.3% nmortality in nymphs within 5 days and 73.3% in adults within seven days, along with significant weight loss. Treated females showed marked declines in fecundity, ovarian degeneration, and deficient yolk deposition. RT-qPCR confirmed significant downregulation of Vg1, VgA, and VgR. These findings establish Syx1A as a regulator of growth and reproduction in citrus psyllids via modulation of yolk synthesis. RNAi targeting of Syx1A represents a promising strategy for ecologically sound pest control and may contribute to efforts in halting the transmission of the Huanglongbing pathogen CLas. Full article

Using multiple species in native plant communities may improve control efficiency compared with single-species use. We conducted field investigations to assess the effects of Artemisia argyi, Portulaca oleracea, and their mixtures on the growth and reproduction of Mikania micrantha, followed by a greenhouse de Wit replacement series to compare different combinations of M. micrantha, A. argyi, and P. oleracea in terms of multispecies competition, phytoallelopathy, and photosynthesis. Field investigation showed that compared with M. micrantha monoculture (Group D), aboveground biomass, total stem length, flower biomass, inflorescence biomass, seed biomass, and seed number of M. micrantha increased in the P. oleracea community (Group B), though only seed number was significantly higher (p < 0.05). In contrast, in the A. argyi community (Group A) and the mixed community of A. argyi and P. oleracea (Group C), all these indicators decreased significantly (p < 0.05), in the order: Group C < Group A < Group D < Group B. This indicates that the mixed community (Group C) most strongly suppressed M. micrantha growth and reproduction. The effects of A. argyi, P. oleracea, and their mixture on the growth of M. micrantha in the greenhouse experiments mirrored the trends observed in field investigations. Calculated indices (relative yield, relative yield total, competitive balance index, and change in contribution) of A. argyi, P. oleracea, and their mixed population on M. micrantha demonstrated a higher competitive ability and higher influence of the combination of the two species compared with either A. argyi or P. oleracea alone. The interspecific phytoallelopathy experiment demonstrated strong allelopathic potential of A. argyi versus M. micrantha (p < 0.05) but showed no significant effect on P. oleracea. The net photosynthetic rate (Pn) of M. micrantha was generally lower in communities with both competitors compared with single-species communities. Our results suggest that, compared with a single plant population, the mixed population of A. argyi and P. oleracea exhibited a markedly enhanced ecological control capability through increased relative competitive ability, strengthened allelopathic inhibition, and markedly reduced photosynthetic efficiency of M. micrantha. Full article

Fruit flies that belong to the genus Zeugodacus (Diptera: Tephritidae) pose significant threats as invasive pests of agricultural crops in Asia and sub-Saharan Africa. The intensification of transboundary trade in fresh horticultural produce has increased the risk of introducing invasive species such as fruit flies, more so through the inadvertent transport of their immature developmental stages. Such immature stages of fruit flies belonging to the Tephritidae family are frequently intercepted at the international borders worldwide and are unable to be identified to the species level using morphological characteristics. Molecular identification using mitochondrial Cytochrome Oxidase I (COI) gene has proven to be quite useful, as they are not constrained by developmental stages, sex, or colour morphs of the pest species in question. Also, real-time PCR-based species-specific assays offer quicker turnaround time since they do not require any post-PCR procedures. This study evaluated the utility of a real-time PCR assay based on the COI gene region to identify Zeugodacus cucurbitae from other Tephritid species. The developed real-time PCR assay provides a swift and precise way of discriminating between these highly invasive pest species during an interception event for rapid decision making. High specificity, having no cross-reactions with closely related Tephritids, and sensitivity of the developed assay will be extremely useful in discriminating Z. cucurbitae from other closely related fruit fly species. Z. cucurbitae-specific real-time PCR developed in this study is appropriate for organizations that carry out routine diagnostics to facilitate fresh produce imports and exports. Our assay is fully optimized for rapid deployment at international borders, offering reliable detection of the target species regardless of developmental stage, sex, or geographic origins. Full article

Peste des petits ruminants is a highly contagious transboundary viral disease that poses a serious threat to small ruminant populations worldwide. In 2024, seven outbreaks of PPR were recorded in sheep flocks from Timiș County, marking the second confirmed incursions of peste des petits ruminants virus (PPRV) in Romania. This study aimed to document the clinical presentation, pathological findings, and diagnostic confirmation with these field outbreaks. Comprehensive field investigations were carried out between July and September 2024, including clinical examinations, post mortem analysis, serological screening, and molecular detection using reverse transcription polymerase chain reaction (RT-PCR). A total of 13,203 sheep were evaluated, with an overall mortality rate of 12.77%. Characteristic clinical signs included mucopurulent nasal discharge, oral erosions, respiratory distress, and diarrhea. Gross lesions observed during necropsy included hemorrhagic bronchopneumonia, bile-stained liver, catarrhal enteritis, and mucosal hemorrhages. Serological testing revealed flock-level seroprevalence rates ranging from 46.7% to 80.0%, with higher rates observed in older animals. RT-PCR confirmed PPRV infection in all affected flocks. Our findings provide strong evidence of virulent PPRV circulation in an area where the virus had not been reported before. The results highlight an urgent need to strengthen surveillance systems, enhance diagnostic capacity, and foster cross-border collaboration. These field-based insights can contribute to both national and international efforts aimed at controlling and ultimately eradicating the disease. Full article

Peste des Petits Ruminants (PPR) is a highly contagious viral disease of small ruminants that severely threatens rural livelihoods and global food security. Under the Global Framework for the Progressive Control of Transboundary Animal Diseases (GF-TADs), the international animal health community has set the ambitious goal of eradicating PPR by 2030. However, significant disparities persist in the progression of PPR control across regions. This scoping review assesses the setbacks, deviations, and progress of 42 countries in Eastern, Western, and Northern Africa, as well as West Eurasia, toward achieving official freedom-from-PPR status. Progress was evaluated across key areas using the stepwise PPR Global Control and Eradication Strategy (GCES) approach and the PPR Monitoring and Assessment Tool (PMAT). The eligibility criteria included PubMed peer-reviewed studies, FAO/WOAH reports, presentations, guidelines, and country/region-specific PPR control plans from 2014 through 2024. The data are generated using qualitative and quantitative analyses, including spatial mapping and GCES stepwise progress evaluation. The findings reveal that many (31%) countries in the assessed regions remain in Stage 1 of the Progressive Stepwise Approach, whereas 59.5% have reached Stages 2 and 3, and only 4.8% are in Stage 4. Countries in Western Eurasia have achieved significant progress towards PPR control, with countries achieving PPR-free status, whereas, compared to Eastern and Northern Africa, the Western African region remains in the early control stages due to infrastructure gaps and resource constraints. Additionally, the recent suspension of PPR-free status in Romania, Greece and Hungary following disease emergence underscored vulnerabilities in historically free countries. The analysis results reiterate the critical role of regional collaboration, surveillance tools, and the integration of wildlife monitoring in advancing PPR control. These insights provide actionable pathways to addressing persistent barriers, highlighting the importance of adaptable, evidence-based approaches in achieving the global goal of PPR eradication by 2030. Full article

The banana pseudostem weevil (BPW), Odoiporus longicollis (Oliver), is one of the most destructive pests of bananas that is seriously affecting the yield and quality of bananas. We isolated pathogens from banana pseudostem weevils in Xishuangbanna and Dongchuan, Yunnan, China, and explored their biological characteristics. The pathogenicity of the strains was verified through laboratory and greenhouse inoculation experiments. The results showed that four strains of fungi were identified and confirmed as Beauveria caledonica (Bc) via ITS-rDNA sequencing. Optimal in vitro culture conditions were found to be a photoperiod of 24 h light, 25 °C temperature, and 18 days on potato dextrose agar (PDA) medium with insect meal. Under these conditions, the Cs-1 strain achieved a colony diameter of 65.17 ± 0.74 mm and spore production of 1.24 × 10⁸ cfu/cm². The Cs-1 strain had the shortest lethal time (LT₅₀) of 9.36 days at an inoculum of 1.00 × 10⁹ cfu/mL, with a lethality of 86.67% after 20 days. The Cs-3 strain showed 77.78% lethality at 1.00 × 10⁸ cfu/mL after 20 days. Despite variations in virulence, lethality did not correlate with major cuticle-degrading enzymes. The Cs-3 strain demonstrated effective biocontrol in greenhouse tests. Banana plants suffered significant damage without Bc-treated BPW, while the treated plantlets thrived. The mortality rate reached 82.78% after 35 days. This study marks the first identification of these entomopathogenic fungi (EPF) in Yunnan, China, highlighting B. caledonica’s potential for biocontrol application. Full article

Interactions between species give rise to chemical pathways of communication that regulate the interactions of transboundary species. The communication between nematodes and other species primarily occurs through the regulation of chemicals, with key species including plants, insects, bacteria, and nematode-trapping fungi that are closely associated with nematodes. G protein-coupled receptors (GPCRs) play a crucial role in interspecies communication. Certain flp genes, which function as GPCRs, exert varying degrees of influence on how nematodes interact with other species. These receptors facilitate the transmission of corresponding signals, thereby completing the interactions between species. This paper introduces the interactions between nematodes and other species and discusses the role of GPCRs in these organisms, contributing to a deeper understanding of the impact and significance of GPCRs in cross-border regulation between nematodes and other species. Furthermore, it is essential to leverage GPCRs in efforts to control pests. Full article

Rice brown spot disease, caused by Bipolaris oryzae, is a significant fungal disease that poses a major threat to global rice production. Despite its widespread impact, genomic studies of B. oryzae remain limited, particularly those involving high-quality genomic data. In this study, we performed whole-genome sequencing of the B. oryzae strain RBD1, which was isolated from the demonstration field for upland rice cultivation in Haozhiba Village, Lancang County, Pu’er City, Yunnan Province, China, using a combination of second-generation Illumina sequencing and third-generation Single-Molecule Real-Time (SMRT) sequencing. The assembled genome was 37.5 Mb in size with a G + C content of 49.39%, containing 42 contigs with a contig N50 of 2.0 Mb. Genomic analysis identified genes related to carbon, nitrogen, and lipid metabolism, highlighting the strain’s metabolic flexibility under diverse environmental conditions and host interactions. Additionally, we identified pathogenicity-related genes involved in MAPK signaling, G protein signaling, and oxidative stress responses. Under 1.2 M sorbitol-induced osmotic stress, we observed significant differences in growth responses between RBD1 and the rice blast fungus Magnaporthe oryzae H7. Transcriptomic analysis using Illumina sequencing revealed that RBD1 responds to osmotic stress by enhancing carbohydrate metabolism, fatty acid degradation, and amino acid synthesis, while H7 primarily relies on protein synthesis to enhance growth tolerance. This study provides a valuable foundation for understanding the pathogenic mechanisms of rice brown spot and future disease control strategies. Full article