Search Results (772)

The integration of essential oils (EOs) with biological control agents offers a promising alternative to synthetic pesticides, though compatibility remains unclear. This study evaluated nutmeg (Myristica fragrans, NM), cinnamon (Cinnamomum verum, CIN), and clove (Syzygium aromaticum, CL) specifically on S. oryzae and L. distinguendus. Olfactory and behavioral responses to whole EOs and major constituents (myristicin, cinnamaldehyde, eugenol) were analyzed using the area preference method (APM) and two-choice behavioral bioassay (TCB), with confirmation by gas chromatography–mass spectrometry (GC-MS). In S. oryzae, APM showed attraction to all three EOs (PI = 0.14 to 0.56). A paradox emerged, however, as single constituents were mostly repellent (eugenol: PI = −0.58 to −0.70; cinnamaldehyde: PI shifted from 0.16 to −0.20), underscoring the complexity of EO mixtures where multiple compounds act jointly rather than individually. In contrast, L. distinguendus strongly avoided CL and CIN in TCB, with fewer than 30% of parasitoids choosing the EO-treated side (χ² test, p < 0.05). CIN therefore demonstrated selective potential, simultaneously attracting S. oryzae while repelling L. distinguendus. These findings highlight the dual role of EOs as botanical pest control tools, while stressing the need to consider non-target effects before practical application. Full article

The effects of wildfires and prescribed burnings on soil are highly variable. In order to evaluate the effects of different burning intensities on soil properties, a surface-controlled burn of undisturbed soil monoliths was carried out by combining temperatures (50 and 80 °C) and residence times (12 and 24 min). The effects of this burning gradient are evaluated at two soil depths (0–1 and 1–3 cm), with time (just after burning or immediate effects, T0, and five months later, T5), as well as the influence of ash (presence or absence). The results indicate that most soil properties were affected by the burning gradient applied only in the most superficial cm (0–1 cm), with few effects at greater depths. The most intense burn had the strongest immediate impact, reducing soil organic carbon, recalcitrant organic carbon, and microbial biomass carbon, as well as increasing the labile organic carbon and the microbial activity. On the other hand, this burning caused a strong decrease in soil water repellency at a 0–1 cm depth and increased it at 1–3 cm. In contrast, medium-intensity burning caused the opposite effect, increasing water repellency at the soil surface and reducing it at 1–3 cm. As a result of the mineralization of organic matter, the EC and pH increased significantly in all burning combinations and both soil depths studied. After five months (T5), several of these parameters tended to approach the values of unburned soil. Full article

The chemical composition of leaf essential oil of the harmful invasive species Chromolaena odorata collected in Vietnam was analyzed by GC/MS and chiral GC. All three essential oil samples (O1, O2 and O3) in this study fell into chemotype I characterized by α-pinene/geigerene/germacrene D/(E)-β-caryophyllene from a total of six different chemotypes. Chemotype I demonstrated larvicidal effects against Aedes aegypti (Linnaeus, 1762), Aedes albopictus Aedes albopictus (Skuse, 1894), Culex fuscocephala (Theobald, 1907) and Culex quinquefasciatus (Say, 1823), with 24 h LC₅₀ values ranging from 11.73 to 69.87 µg/mL. In contrast, its microemulsion formulation exhibited enhanced toxicity, yielding 24 h LC₅₀ values between 11.16 and 32.43 µg/mL. This chemotype also showed repellent efficacy against Ae. aegypti, with protection times ranging from 70.75 to 122.7 min. Fumigant toxicity was observed against Aedes aegypti, with LC₅₀ values of 40.27% at 0.5 h and 0.34% at 24 h. Molluscicidal activity was recorded with 48 h LC₅₀ values between 3.82 and 54.38 µg/mL against Indoplanorbis exustus (Deshayes, 1833), Pomacea canaliculate (Lamarck, 1822), Physa acuta (Draparnaud, 1805). Additionally, the chemotype exhibited acetylcholinesterase inhibitory activity, with an IC₅₀ value of 70.85 µg/mL. Antimicrobial potential was also demonstrated, with MIC values ranging from 2.0 to 128.0 µg/mL against Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella enterica, and Candida albicans. The C. odorata essential oil can be considered as a potential bioresource for human health protection strategies. Full article

The fall armyworm, Spodoptera frugiperda, is a long-distance migratory pest, which invaded the African continent in 2016, causing enormous losses to agricultural crops, especially maize. Synthetic insecticides are primarily used for managing S. frugiperda, but they leave residues on human food and animal feed and also cause environmental hazards. We evaluated the crude ethanolic extract of Piper guineense fruits for contact toxicity on S. frugiperda larvae and determined the lethal concentration (LC₅₀) of the extract. Additionally, we conducted an electrophysiological (EAG) experiment to determine the responses of adult S. frugiperda males and females to P. guineense and determined whether the extract influenced mating, oviposition, and repellence to the adult female. We found that P. guineense extract caused significantly higher mortality to S. frugiperda larvae than an ethanol control. Electrophysiologically, we observed significantly higher responses to the extract than the control, with some variations in response between the sexes. A wind tunnel experiment revealed that females moved more towards the control than towards the extract. Taken together, our results confirm that P. guineense extract is effective against S. frugiperda larvae and adults. Future research should explore the responses of S. frugiperda to P. guineense extract on a field scale. Full article

Orange spiny whitefly (Aleurocanthus spiniferus Quaintance) is a major pest with economic significance to tea plants, as both nymphs and adults suck plant sap and contribute to the development of tea sooty mold. The occurrence of this pest varies considerably among different tea cultivars, even within the same plantation. This study aims to characterize the bioactive constituents of tea volatiles mediating A. spiniferus host selection, and leverage these semiochemicals to develop effective field trapping systems. Through field investigations and Y-tube olfactometer tests, we identified two highly preferred tea cultivars (‘Huangjinya’ and ‘Fuding white tea’) and two cultivars (‘Baiye No. 1’ and ‘Longjing 43’) that were not preferred. Behavioral assays and gas chromatography-mass spectrometry (GC-MS) analysis revealed four attractive compounds [hexanol, (E)-2-hexenal, linalool, and (E,E)-α-farnesene] and two repellent compounds [nonanal and (Z)-3-hexenol] in the volatile emissions of the four cultivars. A hexane solution (10 µL) of nonanol, (Z)-3-hexenol, linalool, and (E,E)-α-farnesene at a concentration of 100 µg/µL was able to elicit an obvious electrophysiological (EAG) response. In field trials, the synergistic bait trap equipped with two types of attractants, 500 µL of hexane solution of the mixture of linalool and (E,E)-α-farnesene (3:1, v/v), and the mixture of linalool and (Z)-3-hexenol (3:1, v/v) at the concentration of 100 μg/μL, showed significantly higher attractant efficacy and selectivity. Overall, this study indicates that tea volatiles play a crucial role in the host selection of A. spiniferus, and the synthetic mixtures of tea volatiles have the potential to be developed as commercial plant-based attractants for adult A. spiniferus. This study contributes to the development of sustainable, environmentally friendly management strategies for a pest that is challenging to prevent and control. Full article

This study explores the sustainable extraction and application of natural dyes from figs (Ficus carica) and Eucalyptus leaves using an aqueous alkaline medium. The dyeing process was optimized for cotton fabric using the exhaust-dyeing method. Fabrics dyed with Ficus carica extract and its blend with Eucalyptus exhibited enhanced color strength, excellent crocking fastness (rated 4–5), and good washing fastness (rated 3–4 on the gray scale). The use of Aloe barbadensis Miller as a bio-mordant significantly improved dye fixation, resulting in deeper, earthy shades, such as green, yellow–green, and yellowish brown. The highest K/S value (5.85) was recorded in samples treated with a mordant, sodium chloride (NaCl), and the combined dye extracts, indicating a synergistic effect among the components. Mosquito repellency tests revealed that treated fabrics exhibited up to 70% repellency, compared to just 20% in undyed samples. Antibacterial testing against E. coli showed that dyed fabrics achieved over 80% bacterial reduction after 24 h, indicating promising antimicrobial functionality. Air permeability slightly decreased post-dyeing due to the potential shrinkage in cotton fabrics. Furthermore, adsorption studies showed a removal efficiency of 57% for Ficus carica dye on graphene oxide (GO) under ultrasonication. These findings confirm the potential of GO as an effective adsorbent material for treating wastewater from natural textile dyes. Overall, the study highlights the environmental safety, functional performance, and multifunctional advantages of plant-based dyeing systems in sustainable textile applications. Full article

Aedes aegypti, also known as the yellow fever mosquito, presents a major public health challenge, highlighting the need for effective biorational agents for mosquito control. Here, we investigated the synergistic effects of essential oil mixtures derived from Hypenia irregularis that is a mint-family shrub native to Brazil’s Cerrado biome, known as “alecrim do Cerrado”, in combination with essential oils from noni (Morinda citrifolia), Brazilian mint (“salva-do-Marajó”, Hyptis crenata), and lemongrass (Cymbopogon citratus) against Ae. aegypti. We conducted phytochemical analyses and assessed larvicidal, repellent, and oviposition deterrent activities. Using in silico methods, we predicted molecular interactions between key essential oil components and physiological targets involved in repellent action (odorant-binding protein AeagOBP1 and olfactory receptor Or31) and larvicidal activity (GABA and octopamine receptors, TRP channels, and acetylcholinesterase [AChE]). Major compounds identified included octanoic acid (23%; Hipe. irregularis × M. citrifolia), 2,5-dimethoxy-p-cymene (21.9%; Hipe. irregularis × Hypt. crenata), and citral (23.0%; Hipe. irregularis × C. citratus). Although individual oils showed strong larvicidal activity (Hipe. irregularis LC₅₀ = 2.35 µL/mL; Hypt. crenata = 2.37 µL/mL; M. citrifolia and C. citratus = 2.71 µL/mL), their mixtures did not display synergistic effects. Similarly, repellency and oviposition deterrence were comparable to DEET for individual oils but were not enhanced in mixtures. Notably, the Hipe. irregularis × C. citratus essential oil blend reduced oviposition deterrence. Molecular docking confirmed strong binding of major oil components to AeagOBP1 and Or31, supporting their role in repellency. For larvicidal effects, AChE showed the highest predicted binding affinity. Overall, our findings suggest that H. irregularis, Hypt. crenata, C. citratus, and M. citrifolia (alone or in 1:1 mixture) are promising, sustainable agents for A. aegypti control. Full article

Varroa destructor represents a major threat to honeybee colonies worldwide, prompting the search for alternative organic acaricides. This study evaluated the biological activity of essential oils extracted from three Patagonian wild plants—Adesmia boronioides, Dysphania multifida, and Senecio filaginoides—on both V. destructor and Apis mellifera. Chemical analysis revealed that A. boronioides oil was dominated by esquelenone (34.49%), D. multifida by ascaridole (34.87%), and S. filaginoides by α-pinene (40.87%). All essential oils exhibited acaricidal activity, with D. multifida showing the lowest LC₅₀ against V. destructor (1.1 µL/mL at 24 h). Toxicity assays on adult bees indicated that A. boronioides and D. multifida significantly reduced bee survival, whereas S. filaginoides did not appear to cause significant mortality (LC₅₀ = 139.5 µL/mL). Repellency tests for A. boronioides and D. multifida showed significant mite repellence. Larval assays revealed a high survival rate under S. filaginoides treatment (survival rate > 80.24%), in contrast to the reduced viability observed with the other oils. The high selectivity index of S. filaginoides underscores its potential as a selective and safe botanical acaricide. Moreover, its LC₅₀ decreased over time, suggesting a residual acaricidal effect. These findings support S. filaginoides as a promising candidate for sustainable V. destructor control. Full article

The increasing environmental and health concerns about synthetic pesticides have compelled researchers to investigate more sustainable, plant-based substitutes for pest management. Due to their unique modes of action and biodegradability, essential oils (EOs) represent effective bio-pesticides. This study examines the biological activities of Artemisia vulgaris (Asteraceae) EO (AVEO) against Aceria pongamiae Keifer (Eriophyidae), a destructive gall mite on Pongamia pinnata (Fabaceae), using fumigation, contact toxicity, and repellency assays for the first time. AVEO was isolated through hydro-distillation, yielding 0.86 ± 0.14% v/w and analyzed by GC-MS/MS, with camphor (28.94%), 4-tert-butylaniline (19.79%), α-pinene (6.61%), eucalyptol (6.39%), fenchol (6.03%), and camphene (5.43%) identified as major constituents. The bioassay of fumigation (0.25–1 µL/mL air) showed LC₅₀ values decreased significantly from 1.29 (24 h) to 0.43 µL/mL air (72 h), while LC₅₀ values of contact toxicity bioassay (2.50–10 µL/mL) declined from 37.37 to 4.56 µL/mL over the same period. Repellency reached 86.11% (Class V) at 0.1 µL/mL (72 h), indicating intense concentration and time-dependent efficacy. These results indicate AVEO’s potential as a green acaricide, highlighting potent fumigant, contact, and repellent activities against A. pongamiae, positioning it as an eco-friendly alternative to synthetic acaricides for sustainable pest control practices with reduced environmental degradation. Full article

The complex systems approach to cognitive–motor processing values multifractal nonlinearity as a key formalism in understanding internal interactions across multiple scales that preserve adequate task-directed behaviors. By using a computer task with increasing difficulty, we focused on the potential link between the difficulty threshold during a task, assessed by the individual’s score ceiling, and the corresponding level of multifractal nonlinearity in movement behavior, assessed based on a time series of cursor displacements. Entropy-based multifractality (MF) and multifractal nonlinearity obtained using a t-test comparison between the original and linearized surrogate series (t_MF) of the time series characterized individual adaptive capacity. A time-varying increase in the score helped in assessing performance when facing increasing difficulty. Twenty-one participants performed a herding task (7 min), which involves keeping three moving sheep near the center of a screen by controlling the mouse pointer as a repelling shepherd dog. The more the score increased, the more the increased herd movement amplitude amplified task difficulty. The time course of the score, score dynamics (score-dyn), markedly diverged across participants, exhibiting a ceiling effect in some during the last third of the task (phase 3). This observation led us to arbitrarily distinguish three phases of the same duration and focus on phase 3, where marked differences in score-dyn emerged. Hierarchical clustering of principal components, starting with principal component analysis, identified three clusters among the participants: cluster 1 was defined by an underrepresentation of score-dyn, MF, and t_MF; cluster 2 was defined by an overrepresentation of MF; and, as a critical outcome, cluster 3 was defined by an overrepresentation of score-dyn and t_MF. Accordingly, participants belonging to cluster 3 had the highest score-dyn and t_MF. Our interpretative hypothesis is that internal interactions that adequately perform the task are reflected in a high degree of multifractal nonlinearity. These findings extend the notion that multifractal nonlinearity is a useful conceptual framework for shedding light on adaptive behavior during complex tasks. Full article

Herbivore-induced plant volatiles (HIPVs) are well known for their roles in herbivore deterrence and attraction of natural enemies, but their direct impact on insect reproduction remains largely unexplored. In this study, we provide novel evidence that two representative HIPVs, 2-heptanol and α-cedrene, exert opposing effects on the reproduction of Chilo suppressalis, a major rice pest. While both volatiles repelled adults, α-cedrene unexpectedly enhanced oviposition, whereas 2-heptanol significantly suppressed egg laying. To examine these effects, we conducted oviposition assays, preoviposition and longevity tests, combined with qPCR and transcriptome analyses to explore underlying molecular responses. Mechanistically, α-cedrene upregulated Kr-h1, a gene linked to juvenile hormone signaling and vitellogenesis, promoting reproductive investment. Transcriptomic profiling revealed divergent molecular responses: α-cedrene activated reproductive pathways, whereas 2-heptanol induced stress- and immune-related genes, suggesting a trade-off between stress defense and reproduction. These findings demonstrate that HIPVs can exert compound-specific reproductive effects beyond repellency. This work fills a key knowledge gap and highlights the potential of HIPVs as precision tools in pest management strategies that exploit behavioral and physiological vulnerabilities beyond repellency. Full article

The utilization of Unmanned Aerial Vehicles (UAVs) in missions such as reconnaissance and surveillance has grown rapidly, underscoring the need for efficient path planning algorithms that ensure both optimality and collision avoidance. The A-star algorithm is widely used for global path planning due to its ability to generate optimal routes; however, its high computational cost makes it unsuitable for real-time applications, particularly in unknown or dynamic environments. For local path planning, the Artificial Potential Field (APF) algorithm enables real-time navigation by attracting the UAV toward the target while repelling it from obstacles. Despite its efficiency, APF suffers from local minima and limited performance in dynamic settings. To address these challenges, this paper proposes the A-star-Guided Potential Field (AGPF) algorithm, which integrates the strengths of A-star and APF to achieve robust performance in both global and local path planning. The AGPF algorithm was validated through simulations conducted in the Robot Operating System (ROS) environment. Simulation results demonstrate that AGPF produces smoother and more optimal paths than A-star, while avoiding the local minima issues inherent in APF. Furthermore, AGPF effectively handles moving and previously unknown obstacles by generating real-time avoidance trajectories, demonstrating strong adaptability in dynamic and uncertain environments. Full article

Root-knot nematode (Meloidogyne incognita) is a globally destructive plant-parasitic nematode that severely impedes the sustainable production of horticultural crops. Metabolic reprogramming in plant roots represents the host response to M. incognita infection that can also be exploited by the nematode to facilitate its parasitism. In this study, untargeted metabolomics was employed to analyze metabolic changes in cucumber roots following nematode inoculation, with the goal of identifying differentially accumulated metabolites that may influence M. incognita behavior. Metabolomic analysis revealed that M. incognita significantly altered the cucumber root metabolome, triggering an accumulation of lipids and organic acids and enriching biotic stress-related pathways such as alkaloid biosynthesis and linoleic acid metabolism. Among differentially accumulated metabolites, myristic acid and hexadecanal were selected for further study due to their potential roles in nematode inhibition. In vitro assays demonstrated that both metabolites suppressed egg hatching and reduced infectivity of M. incognita, while pot experiments indicated a correlation between their application and reduced root gall formation. Chemotaxis assays further revealed that both metabolites exerted repellent effects on the chemotactic migration of M. incognita J2 and suppressed the transcriptional expression of two motility-and feeding-related neuropeptides, Mi-flp-1 and Mi-flp-18. In conclusion, this study demonstrates the significant potential of differentially accumulated metabolites induced by M. incognita infection for nematode disease control, achieved by interfering with nematode chemotaxis and subsequent infection. This work also provides deeper insights into the metabolomic mechanisms underlying the cucumber-M. incognita interaction. Full article

Allyl isothiocyanate (AITC) is a naturally occurring, pungent compound abundant in cruciferous vegetables and functions as a repellent for various organisms. The antibacterial effect of AITC against various bacteria has been reported, but there are no reports on the effect on Streptococcus mutans, a major bacterium contributing to dental caries. In this study, we investigated the inhibitory effect and mechanism of AITC on the survival and growth of S. mutans. AITC showed an antibacterial effect in a time- and concentration-dependent manner. In addition, bacterial growth was delayed in the presence of AITC, and there were almost no bacteria in the presence of 0.1% AITC. In a biofilm assay, the amount of biofilm formation with 0.1% AITC was significantly decreased compared to the control. RNA sequencing analysis showed that the expression of 39 genes (27 up-regulation and 12 down-regulation) and 38 genes (24 up-regulation and 14 down-regulation) of S. mutans was changed during the survival and the growth, respectively, in the presence of AITC compared with the absence of AITC. Protein–protein interaction analysis revealed that AITC mainly interacted with genes of unknown function in S. mutans. These results suggest that AITC may inhibit cariogenicity of S. mutans through a novel mechanism. Full article

Benzoxazine resins are gaining attention for their impressive thermal stability, low water uptake, and strong mechanical properties. In this work, two new bio-based benzoxazine monomers were developed using renewable arbutin: one combined with 3-(2-aminoethylamino) propyltrimethoxysilane (AB), and the other with furfurylamine (AF). Both were synthesized using a simple Mannich-type reaction and verified through FT-IR and ¹H-NMR spectroscopy. By blending these monomers in different ratios, copolymers with adjustable thermal, dielectric, and surface characteristics were produced. Thermal analysis showed that the materials had broad processing windows and cured effectively, while thermogravimetric testing confirmed excellent heat resistance—especially in AF-rich blends, which left behind more char. The structural changes obtained during curing process were monitored using FT-IR, and XPS verified the presence of key elements like carbon, oxygen, nitrogen, and silicon. SEM imaging revealed that AB-based materials had smoother surfaces, while AF-based ones were rougher; the copolymers fell in between. Dielectric testing showed that increasing AF content raised both permittivity and loss, and contact angle measurements confirmed that surfaces ranged from water-repellent (AB) to water-attracting (AF). Overall, these biopolymers (AB/AF copolymers) synthesized from arbutin combine environmental sustainability with customizability, making them strong candidates for use in electronics, protective coatings, and flame-resistant composite materials. Full article