Search Results (390)

Background/Objectives: Within their host trees, mountain pine beetles (MPBs, Dendroctonus ponderosae) interact with many fungal species, each releasing a unique profile of volatile organic compounds (VOCs). The FVOCs released by the two primary symbionts of MPBs, Grosmannia clavigera and Ophiostoma montium, have been found to enhance MPB attraction in the field and laboratory studies. Opportunistic, saprophytic fungal species, such as Aspergillus sp. and Trichoderma atroviride, are also common in MPB galleries and can negatively impact MPB fitness. However, little is known about the FVOCs produced by these fungal species and how they may impact MPB feeding and attraction. Methods: To address this knowledge gap, we characterized the FVOC profile of T. atroviride, and performed bioassays to test the effects of its FVOCs on MPB attraction and feeding activity. Results: Our chemical analysis revealed several FVOCs from T. atroviride known to inhibit the growth of competing fungal species and impact subcortical-beetle attraction. Conclusions: From those FVOCs, we recommended four compounds—2-pentanone, 2-heptanone, 2-pentanol, and phenylethyl alcohol—for use in future field tests as anti-attraction lures for MPBs. In bioassays, we also observed strong MPB repellency from FVOCs released by T. atroviride, as well as the mild effects of FVOCs on MPB feeding activity. Our findings highlight the potential for these FVOCs to be utilized in the development of more effective MPB anti-attractant lures, which are crucial for the monitoring and management of low-density MPB populations. Full article

Spodoptera frugiperda is a major agricultural pest worldwide, causing significant economic loss to maize crops. Its control largely depends on synthetic pesticides, which contribute to resistance development, harm non-target organisms, and lead to environmental degradation. Essential oils and their main components offer a more sustainable and ecologically sound alternative for the management of S. frugiperda. This study evaluated the effects of selected essential oils and their bioactive compounds on the survival and behavior of S. frugiperda using toxicity and preference assays. Peppermint essential oil and its major constituent, pulegone, significantly reduced the survival of S. frugiperda, with effects similar to those caused by synthetic insecticides. Eucalyptus essential oil and its main compound, 1,8-cineole, also influenced the behavior of S. frugiperda, suggesting potential for use in repellents. These findings highlight the use of essential oils and their main constituents/active constituents as bioinsecticides and their integration into environmentally friendly pest management strategies. Full article

To date, various species of Erigeron genus have been used both in the ethnopharmacology of numerous nations across the world and in contemporary herbal practices. The objective of this study is to revise the phytochemical data on the essential oils (EOs) of various fleabanes species and to evaluate the variability of their biological activities. Up to June 2025, this review provides an updated overview of 105 literature sources (published during last 25 years) related to 14 Erigeron sp. (native, naturalized, or invasive) which have been investigated extensively and are of the greatest significance. It summarizes the compositional variability of the EOs and their pharmacological and toxic effects, such as anti-inflammatory, anticancer, antiproliferative, skin regeneration, antioxidant, antifungal, antibacterial, insecticidal, larvicidal, repellent, and allelopathic activity. The EOs of each Erigeron species were characterized, and a chemical structure of 43 major constituents is presented herein. The most characteristic and prevalent compounds were found to be limonene, δ-3-carene, matricaria ester, lachnophyllum ester, germacrene D, β-caryophyllene, β-farnesene, α-bergamotene, allo-aromadendrene, etc., in the EOs from the E. acris, E. annuus, E. bonariensis, E. canadensis, E. floribundus E. mucronatus, and E. speciosus plants. Major constituents, such as borneol, bornyl acetate, modhephen-8-β-ol, cis-arteannuic alcohol, β-caryophyllene, and τ-cadinol, were found in the oils of E. graveolens (Inula graveolens). A paucity of data concerning E. incanus EOs was revealed, with the prevalence of 3-hydroxy-4-methoxy cinammic acid and thymol acetate noted in the oils. The EOs from E. multiradiatus and E. sublyratus were comprised mainly of matricaria and lachnophyllum esters. The available data on EOs of E. ramosus is limited, but the main constituents are known to be α-humulene, 1,8-cineole, eugenol, and globulol. The EOs containing appreciable amounts of matricaria and lachnophyllum esters exhibited strong anticancer, anti-inflammatory, antimicrobial, larvicidal, and repellent activities. Repellence is also related to borneol, bornyl acetate, caryophyllene derivatives, τ-cadinol, modhephen-8-β-ol, and cis-arteannuic alcohol. Cytotoxicity was determined due to the presence of limonene, δ-3-carene, α- and β-farnesene, (E)-β-ocimene, ledene oxide, sesquiphellandrene, and dendrolasin in the fleabanes EOs. Skin regeneration and antifungal properties were related to germacrene D; and anti-inflammatory effects were determined due to high amounts of limonene (E)-β-ocimene, lachnophyllum ester, and germacrene D. The antimicrobial properties of the oils were conditioned by appreciable quantities of limonene, β-pinene, 1,8-cineole, carvacrol, thymol acetae, β-eudesmol, 2,6,7,7α-tetrahydro-1,5-dimethyl-1H-indene-3-carboxaldehyde, caryophyllene and its oxide, allo-aromadendrene, α-humulene, farnesene, carvacrol, and eugenol. This review provides a foundation for further studies on volatile secondary metabolites to explore the potential sources of new biologically active compounds in Erigeron sp. Full article

The sorghum aphid (Melanaphis sacchari (Zehntner, 1897)), a globally destructive pest, severely compromises sorghum yield and quality. This study compared aphid-resistant (HX133) and aphid-susceptible (HX37) sorghum (Sorghum bicolor (L.) Moench) cultivars, revealing that HX133 significantly suppressed aphid proliferation through repellent and antibiotic effects, while aphid populations increased continuously in HX37. Transcriptome analysis identified 2802 differentially expressed genes (DEGs, 45.9% upregulated) in HX133 at 24 h post-infestation, in contrast with only 732 DEGs (21% upregulated) in HX37. Pathway enrichment highlighted shikimate-mediated phenylpropanoid/flavonoid biosynthesis and glutathione metabolism as central to HX133’s defense response, alongside photosynthesis-related pathways common to both cultivars. qRT-PCR validation confirmed activation of the shikimate pathway in HX133, driving the synthesis of dhurrin—a cyanogenic glycoside critical for aphid resistance—and other tyrosine-derived metabolites (e.g., benzyl isoquinoline alkaloids, tocopherol). These findings demonstrate that HX133 employs multi-layered metabolic regulation, particularly dhurrin accumulation, to counteract aphid infestation, whereas susceptible cultivars exhibit limited defense induction. This work provides molecular targets for enhancing aphid resistance in sorghum breeding programs. Full article

Globally, plant-derived natural products such as essential oils serve as primary sources of functional substances for spices, pharmaceuticals, and other applications. With the increasing focus on health and well-being, alongside ongoing public health challenges, there is a critical need to enhance the deep utilization of natural plant products. Lauraceae family essential oils, characterized by their aromatic, volatile properties and notable biological activities (e.g., antibacterial, antioxidant, insect-repellent), hold significant application value across fragrance, cosmetics, chemical industries, biological pesticides, and medicine. Integrating multi-disciplinary data from biology, genomics, metabolomics, and related fields can accelerate comprehensive insights into the biosynthesis mechanisms and functional roles of these essential oils, thereby promoting the development and application of Lauraceae natural products. This review systematically summarizes the accumulation patterns and compositional characteristics of essential oils across diverse genera of Lauraceae. It further explores the evolutionary dynamics of terpene synthase (TPS) gene families and key genes involved in terpenoid biosynthesis pathways, leveraging genomic datasets from Lauraceae species. Finally, the review highlights future research trends for optimizing Lauraceae essential oil resource utilization and advancing molecular breeding of high-oil-content species within the family. Full article

Background: Chemosensation in ticks opens a novel and unique field for scientific research. This study highlights ticks’ chemosensory system to comprehend its host-searching behavior and other integrated chemistry and biology involving Haller’s structure. Methodology: This study combines microanatomical, electrophysiological, and behavioral experiments to investigate the role of Haller’s organ in adult ticks in response to different classes of organic compounds. Results: We showed the microscopic anatomy of Haller’s organ in Haemaphysalis darjeeling, present at the terminal segment of the first pair of appendages. Haller’s structure serves a vital function in perceiving odor. The electrophysiological activity of adult ticks to different classes of organic compounds via electroscutumography was explored at five different concentrations: w/v 0.001, 0.01, 0.1, 1.0, and 2.0%. Among 55 organic compounds, moderate to high stimulation was recorded with pyruvate (13.28 mv at 2%), ammonia (12.26 mv at 2%), benzoic acid (1.99 mv at 0.001%), isobutyric acid (1.39 mv at 0.001%), 2,6-dichlorophenol (1.34 mv at 0.001%), p-Tolualdehyde (1.26 mv at 2%), tetradecane (1.23 mv at 2%), docosane (1.17 mv at 2%), citronellal (1.13 mv at 0.1%), isopropyl acetate (1.05 mv at 0.01%), cyclohexanol (1.03 mv at 2%), 1-octane-3-ol (1.02 mv at 2%), and 1-octanol (1.01 mv at 0.001%). Olfactometric bioassays at w/v 2.0% concentration further confirmed that ammonia, pyruvate, 1-octane-3-ol, hematin porcine, p-Tolualdehyde, methyl salicylate, uric acid, tetradecane, carbon dioxide, propanoic acid, 3-hexanol, hexanoic acid, adenine, 2,6-dichlorophenol, hexadecane, heptanoic acid, pentanoic acid, octadecane, guanine, and nonanoic acid acted as strong attractants, while citronellal, eugenol, butyric acid, geraniol, benzaldehyde, and tiglic aldehyde showed an active repellent effect against the tick species. Conclusions: This investigation provides knowledge of the olfactory sensilla of Haller’s structure as biosensors behind tick olfaction and the possibility for chemical detection of diverse attractants and repellents for future development of anti-tick compounds. Full article

The house fly, Musca domestica L., is a pest of great medical and agricultural importance, serving as a vector for various diseases and undermining the quality of agricultural products. Traditionally, synthetic insecticides have been the primary means of control; however, their efficacy has declined over time, and they are now less preferred due to their safety and environmental concerns. This study evaluated the insecticidal and repellent properties of essential oils from Eucalyptus globulus, Foeniculum vulgare and Salvia officinalis against M. domestica. All EOs exhibited insecticidal activity: eucalyptus achieved 100% fumigant mortality at 34 µL L⁻¹ air and showed the lowest LC₅₀ (18.1 µL L⁻¹ air), while fennel and sage required 50 µL L⁻¹ air. In contrast, fennel showed the highest contact toxicity (100% mortality at 150 µL L⁻¹). Repellency exceeded 87% for all EOs, with sage being the most repellent at the lowest concentration tested (94% at 5 µL L⁻¹). These results highlight the potential use of essential oils and their constituents as environmentally friendly alternatives for the control of M. domestica. However, further field validation and studies on individual components and their synergistic combinations are needed to understand their efficacy and fully optimize their use. Full article

This study evaluated the repellent activity of DEET, eugenol, methyl eugenol, 1,8-cineole, and their combinations against Amblyomma sculptum nymphs through laboratory and field tests. Initially, the botanical compounds were tested individually in Petri dish assays to assess repellent activity over various intervals (1 min to 168 h) at concentrations of 2%. Eugenol and methyl eugenol exhibited the highest average repellent percentages (60 to 90%), with significant effects (p < 0.05) across most evaluation periods, in contrast to 1,8-cineole. Therefore, eugenol and methyl eugenol were selected for combination testing with DEET. The combinations of 7% DEET + 1% eugenol and 7% DEET + 2% methyl eugenol showed the best results, with average repellent efficacy exceeding 85%. The first combination was selected for field evaluation. In this test, volunteers wore treated socks and walked for two hours in a naturally infested area. A significant reduction (p < 0.05) in the number of ticks recovered from the socks was observed in the 7% DEET and 7% DEET + 1% eugenol treatments, with efficacies of 82.5% and 88.5%, respectively, after 120 min. Isolated eugenol showed limited field efficacy, with significant repellent activity (p < 0.05) lasting only 20 min. The results highlight the potential of eugenol and methyl eugenol as repellent compounds, especially when combined with DEET. The field study confirmed the efficacy of the 7% DEET + 1% eugenol. Full article

This study investigated the phytochemical composition and biological activities of Myrtus communis essential oil (EO) from Algeria, focusing on its antimicrobial, antifungal, and insecticidal properties using in vitro and in silico approaches. Gas chromatography–mass spectrometry (GC-MS) analysis identified myrtenyl acetate (57.58%), 1,8-cineole (17.82%), and α-terpineol (6.82%) as the major constituents. M. communis EO exhibited significant antibacterial activity, particularly against Staphylococcus aureus (13.00 ± 0.70 mm) and Salmonella typhimurium (13.00 ± 1.50 mm), with moderate inhibition of Bacillus subtilis (10 ± 1.00 mm) and Escherichia coli (9.00 ± 0.70 mm), while Pseudomonas aeruginosa showed resistance. The antifungal activity was notable against Fusarium oxysporum (16.50 ± 0.50 mm), Aspergillus fumigatus (11.00 ± 1.00 mm), and Penicillium sp. (9.00 ± 0.60 mm) but ineffective against Aspergillus niger. Insecticidal activity against Tribolium castaneum was evaluated using contact toxicity, fumigation toxicity, and repellent activity assays. The EO demonstrated potent insecticidal effects, with an LC₅₀ value of 0.029 µL/insect for contact toxicity and 162.85 µL/L air for fumigation after 96 h. Additionally, the EO exhibited strong repellent activity, achieving 99.44% repellency at a concentration of 0.23 mg/cm² after 24 h. Density functional theory (DFT) calculations provided insights into the molecular geometry and electronic properties of the key bioactive compounds. Molecular docking studies evaluated their binding affinities to bacterial enzymes (DNA gyrase, dihydrofolate reductase6, and Gyrase B) and insecticidal targets (acetylcholinesterase), revealing strong interactions, particularly for geranyl acetate and methyleugenol. These findings highlight M. communis EO as a promising natural antimicrobial and insecticidal agent, with potential applications in plant protection and biopesticide development. Full article

Background: Coleus amboinicus (Lour.) (syn Plectranthus amboinicus) from the Lamiaceae family—a large family of aromatic herbs with many medicinally important species—is a frequently cited species within the Plectranthus genus, renowned for its traditional uses, phytochemical composition, biological activities, and applications in skin care. Methods: A systematic review was conducted following PRISMA guidelines to provide an in-depth understanding of P. amboinicus’ phytochemical composition and biological activity, particularly in dermatological contexts, underscoring its significance in traditional medicine and modern phytochemical research. Results: P. amboinicus extracts and essential oils exhibit significant antimicrobial activity against both Gram-positive and Gram-negative bacteria, and notable antifungal properties, particularly against dermatophytes. Additionally, the species demonstrates remarkable mosquito repellent and anti-parasitic effects, comparable to DEET, and potent anti-inflammatory properties by inhibiting pro-inflammatory cytokines. The plant’s rich polyphenolic content contributes to its significant antioxidant properties, preventing conditions like hyperpigmentation and premature aging. P. amboinicus also exhibits cytotoxic activity against various cancer cell lines and promotes wound healing through its analgesic, anti-inflammatory, and antioxidant abilities. Conclusions: This comprehensive exploration of P. amboinicus validates its diverse therapeutic potential across infectious diseases, oncology, and wound care. Further research and clinical trials are warranted to fully elucidate its mechanisms of action and optimize its therapeutic applications, paving the way for its integration into mainstream medical practices. Full article

Entomopathogenic fungi (EPFs) can influence plant–insect interactions through complex molecular and chemical mechanisms. This study investigates how EPF treatment of tomato plants modulates volatile organic compound (VOC) emissions and subsequent trophic interactions between tomato plants, the herbivorous pest Phthorimaea absoluta, and the parasitic wasp, Trichogramma chilonis. Our results demonstrate that EPF-treated plants exhibited reduced attractiveness to adult P. absoluta moths, which were actively repelled by EPF-induced VOCs. Conversely, these same plants showed enhanced recruitment of the parasitoid T. chilonis, which demonstrated positive chemotaxis toward the modified VOC profile. Chemical analysis revealed significantly elevated emissions of key VOCs in EPF-treated plants, particularly (E)-β-Caryophyllene, β-phellandrene, and α-Phellandrene. This increase is correlated with enhanced production of defense-related phytohormones, including JA, SA, and JA-Ile, which may regulate VOC biosynthesis pathways. Behavioral response studies using synthetic VOCs and electroantennogram (EAG) measurements confirmed that these EPF-induced VOCs elicited strong olfactory responses in both insect species. To summarize, EPF treatment reshapes multitrophic interactions by strategically modulating plant VOC emissions and activating defense signaling pathways in tomato plants, providing new insights for potential applications in sustainable pest management strategies. Full article

In this study, polymer films based on the inorganic sorbents Al₂O₃, ZrO₂ and SiO₂-phenyl with repellent N,N-diethyl-3-methylbenzamide were prepared and used as functional textile coatings. The high sorption activity of oxides with respect to N,N-diethyl-3-methylbenzamide (63–239 mg/g) allows for the use of these compounds as repellent carrier materials, and their mixture with polyacrylates allows for the formation of functional coatings–polymer films. Scanning electron microscopy and Fourier transform infrared spectroscopy results revealed that the inorganic sorbents Al₂O₃, ZrO₂ and SiO₂-phenyl were successfully anchored in the polyacrylate structure, and the FTIR spectra confirmed the presence of repellent molecules. The thermal diffusion parameters of N,N-diethyl-3-methylbenzamide were also calculated via thermogravimetric analysis and high-performance liquid chromatography with diode array detection. The highest thermal diffusion rates and concentrations were observed for the material with Al₂O₃ (up to 148.3∙10⁻⁹ mol at 200 °C), and lower values for ZrO₂ and SiO₂-phenyl (up to 15.2∙10⁻⁹ mol and 34.3∙10⁻⁹ mol at 200 °C, respectively). The heat flux parameter J_f was also calculated according to Onsager’s theory and Fourier’s law. The release of repellent from polymeric materials can be achieved by applying less heat than that required to reach the boiling point of N,N-diethyl-3-methylbenzamide. Full article

Aphis gossypii Glover (Homoptera: Aphidinae), a major pest of Chinese pepper (Zanthoxylum bungeanum Maxim), causes significant agricultural damage. Ginger (Zingiber officinale Roscoe) has shown potential as a source for developing botanical pesticides due to its strong bacteriostatic and insecticidal properties; however, the underlying mechanisms remain poorly understood. This study evaluated the repellent activity of ginger shoot extract (GSE) across four solvent phases—petroleum ether, trichloromethane, ethyl acetate, and methanol—against A. gossypii. The results demonstrated that GSE exhibited significant repellent effects, with the methanol phase showing the most pronounced activity. Twelve fractions were chromatographically separated from the methanol phase, and electroantennography (EAG) analysis revealed that fraction 4 induced strong EAG responses in both winged and wingless aphids. Further identification of active compounds in fraction 4 by gas chromatography–mass spectrometry (GC–MS) indicated the presence of terpenes, aromatics, alkanes, esters, and phenols as major constituents. Subsequent EAG analysis identified several key compounds—octahydro-pentalene (C1), (Z)-cyclooctene (C2), dimethylstyrene (C3), tetramethyl-heptadecane (C5), tetrahydro-naphthalene (C6), and heptacosane (C9)—as responsible for eliciting EAG responses in both aphid forms. Additionally, results from Y-tube olfactometer assays showed that (Z)-cyclooctene and heptacosane were significantly attractive, while octahydro-pentalene acted as a strong repellent to both winged and wingless aphids. These findings offer valuable insights for the development of synthetic attractants and repellents for A. gossypii and provide a theoretical foundation for utilizing ginger in the creation of botanical pesticides targeting this pest. Full article

To investigate the repellent efficacy of commercially available mosquito repellents in China against Haemaphysalis longicornis, four representative DEET-based repellents and biont-derived repellents were selected. This study utilized a modified circular filter paper method repellent testing device to establish an evaluation system for assessing the repellent effects of each product against three developmental stages of H. longicornis: larvae, nymphs, and adults. In our study, for DEET-based repellents, Johnson demonstrated the highest repellency against larvae within 1 h, with an average repellency rate exceeding 80.14%. Yamei and Johnson exhibited repellency rates more than 91.11% for nymphs within 1 h, surpassing the other two DEET products. Repellency rates of Longliqi and Xiaohuanxiong fluctuated between 80.95% and 100% at different time points. Yamei, Longliqi, and Johnson achieved 100% repellency to adults within 1 h, while Xiaohuanxiong showed slightly lower efficacy. The four biont-derived repellents showed significant variations in efficacy: larval-stage repellency ranged from 14.29% to 88.89%, nymphal-stage repellency from 57.89% to 100%, and adult-stage repellency from 50% to 79.49%. CaliforniaBaby exhibited the highest efficacy, comparable or superior to DEET-based products, whereas Longhu demonstrated the weakest repellency and poor persistence. We further conducted a persistence test for CaliforniaBaby and found that it maintained >75% repellency against H. longicornis for 6 h. This study provides scientific evidence for selecting tick repellents in practice, offers guidance for purchasing commercial biont-derived tick repellents, and serves as a reference for developing safer, more effective tick repellents. Full article

The solutions of essential oil (0.5%, 0.8%, and 1.0% w/v) derived from Achillea millefoilum (EOAM) were evaluated for their repellent and insecticidal activity toward Acrobasis advenella, as well as their effects on the activity of selected larval tissue enzymes. The chemical composition of the EOAM analyzed by GC-MS showed that the main compounds included β-pinene, chamazulene, eucalyptol, and β-caryophyllene. Selection tests showed that larvae avoided inflorescences treated with 0.8% and 1.0% EOAM concentrations. The mortality of larvae increased with concentration and time of exposure to the EO, and the highest mortality rate was observed after 72 h. In addition, the impact of EO was examined on the activity of catalase (CAT), polyphenol oxidase (PPO), peroxidase (POX), α- and β-glucosidases, and acetylcholinesterase (AChE), i.e., important antioxidants, detoxification, digestive, and nervous system enzymes. A significant increase in CAT activity was found in larvae treated with 0.8% and 1.0% EOAM after both 24 and 48 h. Initially, treating larvae with 0.5% EO decreased β-glucosidase activity while increasing α-glucosidase activity. Moreover, 0.8% EOAM inhibited the activity of POX. These findings suggest that EOAM can affect important biochemical processes within the tissues of A. advenella larvae, making it a promising agent for the protection of black chokeberry crops. Full article