Araucaria araucana (Molina) K. Koch, an endemic conifer of Chile and Argentina, has been severely impacted in recent years by Araucaria Leaf Damage (ALD). Previous research has established that volatile organic compounds (VOCs) released by healthy (H) and leaf-damaged (LD) Araucaria araucana branches modulate the behavior of Sinophloeus porteri. Specifically, myrcene, the most abundant compound in healthy branches, acts as a repellent to this insect, whereas hibaene, found in high concentrations in leaf-damaged tissue, acts as an attractant. This study compared the chemical profiles of healthy and leaf-damaged branches across two distinct geographic areas: Nahuelbuta (PNN) and Villarrica (PNV) National Parks. Following VOC capture using Porapak Q and subsequent GC-MS analysis, 31 compounds were detected and 29 were identified. The results indicate that hibaene was consistently detected across health categories, whereas camphor was particularly abundant in leaf-damaged trees from PNV. Overall, the data suggest that tree health status is associated with marked changes in VOC profiles, although the present design does not allow constitutive and induced responses to be fully disentangled. Consequently, monitoring these volatile emissions represents a strategic tool for the early detection and mitigation of damage caused by pests and diseases in these forest ecosystems.

Haematobia irritans (L.) (Diptera: Muscidae), commonly known as the horn fly, is one of the most economically significant ectoparasites of cattle worldwide, causing substantial losses in meat, milk, and hide production. Its management has historically relied on broad-spectrum insecticides, whose overuse has driven the emergence of resistant populations and raised environmental concerns, emphasizing the urgent need to alternative, ecofriendly control strategies. A key yet underexplored aspect of horn fly biology is behind one of its characteristic behaviors, oviposition behavior: gravid females deposit eggs almost exclusively in very fresh cattle dung, a preference that diminishes rapidly with time post-defecation. Although volatile organic compounds (VOCs) from dung are known to mediate this behavior, the biological origin of these chemical cues remains poorly characterized. This review proposes that microbial volatile organic compounds (mVOCs) produced by the cattle dung microbiota-particularly anaerobic bacteria derived from the bovine rumen-are major elicitors of horn fly oviposition behavior, constituting a transkingdom chemical signaling system. By systematically cross-referencing VOCs reported in fresh cattle dung with compounds known to elicit electrophysiological and behavioral responses in H. irritans, we identified four key semiochemicals of probable microbial origin: phenol, p-cresol, indole, and α-pinene, produced by bacterial families including Enterobacteriaceae, Clostridiaceae, Paenibacillaceae, and Lactobacillaceae. The temporal decline in dung attractiveness is proposed to reflect the succession of the microbial community from anaerobic to aerobic dominance, with a concomitant shift in the mVOC profile. This hypothesis is further supported by the observation that the early developmental stages of H. irritans harbor an anaerobe-dominated microbiota. This framework may provide opportunities for the development of environmentally friendly blends for horn fly management.

Drosophila suzukii is one of the most destructive pests of soft fruits worldwide due to its high reproductive capacity, wide host range, and great adaptability. In this context, Drimys winteri, a tree native to southern Chile and Argentina, is recognized as a source of bioactive compounds with insecticidal and repellent properties. This study evaluated the repellent and oviposition-deterrent activity of essential oils (EOs) from the bark and leaf of D. winteri on D. suzukii. Chemical analysis by GC/MS showed that both EOs were dominated by monoterpenes, with α-pinene, β-pinene, and D-limonene being the major compounds, while the leaf EO exhibited greater chemical diversity and a higher proportion of sesquiterpenes. In choice bioassays, all treatments generated significant avoidance responses, with a preference for the control. The leaf EO showed the greatest repellent effect, exceeding 85% at 12 h and remaining above 80% at 96 h. In oviposition assays, the leaf EO significantly reduced egg laying at all concentrations, with negative oviposition preference index values indicating a consistent deterrent effect. Overall, the leaf EO of D. winteri showed repellent and oviposition-deterrent effects against D. suzukii under laboratory conditions.

Aegorhinus superciliosus (Coleoptera: Curculionidae) is a polyphagous pest of economic importance in southern Chile, the chemical ecology of which remains poorly characterized. Across insect species, chemosensory proteins, including odorant receptors (ORs), gustatory receptors (GRs), ionotropic receptors (IRs), odorant-binding proteins (OBPs), chemosensory proteins (CSPs), and sensory neuron membrane proteins (SNMPs), mediate the detection of chemical cues involved in host selection, reproduction, and other ecologically relevant behaviors. In this study, the antennal transcriptome of adult A. superciliosus was sequenced and analyzed using a de novo RNA-seq approach. Three independent biological replicates per sex were used for RNA-seq, and the same number of independent biological replicates was used for RT-qPCR validation; sequencing yielded 147,409,936 high-quality reads after quality filtering. A total of 112 candidate chemosensory genes were identified, comprising 43 ORs, 34 OBPs, 10 CSPs, 18 IRs, 5 GRs, and 2 SNMPs. Phylogenetic analyses assigned these candidate proteins to established clades, providing a comparative framework for functional inference for ORs and OBPs. Sex- and tissue-biased expression analyses revealed that several ORs, including AsupOR4, AsupOR19, and AsupOBP13, exhibit antennal enrichment and sex-specific expression patterns. Notably, AsupOR19 and AsupOBP13 displayed strong female-biased expression. In addition, transcripts of selected ORs and OBPs were detected in non-antennal tissues, such as the rostrum and legs, suggesting potential functional versatility beyond canonical olfaction. Together, these findings represent the first molecular identification of the chemosensory repertoire of A. superciliosus. This study establishes a foundation for reverse chemical ecology approaches aimed at identifying behaviorally active volatile organic compounds (VOCs) toward environmentally sustainable strategies for integrated pest management.

ABSTRACT Odorant‐binding proteins (OBPs) are key specialized transporters of odorants. In lepidopteran species, OBPs have evolved to function in the context of sex pheromones, plant volatiles and other olfactory cues. However, most of the evidence is limited to adult stages. In apiculture, the greater wax moth Galleria mellonella , is considered a worldwide‐distributed pest of beehives during its larval stage (waxworms). Current evidence supports olfactory cues for aggregation behavior in the larvae. Nevertheless, proteins (i.e., OBPs) and other odorants remain unknown. Using transcriptomics, 25 OBP candidates were identified. Further relative expression evidence suggested gene regulation of some OBPs dependent on larval development. An OBP, called GmelGOBP2, differentially expressed in gregarious waxworms, though with stable expression during larval instars, was functionally studied. Fluorescence binding assays showed affinity towards 4 out of 26 ligands, namely linoleic acid, oleic acid, undecanol and β‐ionone, in accordance with molecular docking results. Overall, it is believed that GmelGOBP2, though not exclusively, could help in mediating larval behavior towards fatty acids, which are present in the context of beehives.

Biosurfactants are surface-active microbial molecules with increasing industrial relevance as sustainable alternatives to synthetic surfactants. Among them, lipopeptides produced by Bacillus species, particularly surfactin, exhibit strong interfacial activity and biological functionality. In this study, rhizospheric soils from the La Araucanía region, Chile, were explored as a source of biosurfactant-producing bacteria. Eighteen strains were isolated, and two high-performing strains, Solo 1 and Solo 4, were identified as Bacillus amyloliquefaciens and Bacillus subtilis, respectively. Both strains harbored the srfAA gene and produced surfactin isoforms confirmed by MALDI-TOF MS. Kinetic analysis revealed distinct production profiles, with Solo 1 reaching a maximum of 90 mg L-1 at 24 h, whereas Solo 4 showed continuous production up to 224.4 mg L-1 at 72 h. Both biosurfactants exhibited high emulsification capacity (>80%) and stability across wide ranges of temperature, pH, and salinity. Importantly, cell-free supernatants from both strains showed antibacterial and antibiofilm activity against Staphylococcus aureus, with Solo 4 reaching 81% biofilm inhibition. In addition, surfactin-enriched extracts inhibited the pathogenic bacterium Pseudomonas syringae and the filamentous fungus Fusarium oxysporum, with Solo 4 consistently showing stronger antimicrobial performance. Overall, these findings identify Solo 4 as a promising native Bacillus strain for future development of biosurfactant-based systems aimed at antimicrobial control, biofilm management, agricultural pathogen suppression, surface sanitation, and environmentally compatible biotechnological processes.

Botrytis cinerea causes gray mold and is considered the second most important fungal phytopathogen. Natural compounds such as menthol and menthone have emerged as sustainable tools for reducing fungal infections and mitigating the adverse effects of synthetic fungicides. Nevertheless, there is limited information about the physiological mechanisms of menthol and menthone on B. cinerea. This study focused on elucidating the response of B. cinerea to the exposure to menthol and menthone in reducing fungal growth and exploring their use in lipid nanoparticles. The results showed that both compounds significantly reduced mycelial growth by ∼ 100%. Otherwise, menthol reduced spore germination by 71-100%, whereas menthone achieved only 28-37% inhibition. Both compounds reduced the dry weight of fungal cultures by more than 80% and increased pH and electrical conductivity, reflecting dysfunction of cell membranes. Besides, the compounds enhanced the release of cellular material that absorbs at OD260nm and soluble proteins. An increased cell membrane damage and reduced esterase activity, mitochondrial activity, and cell membrane potential were observed. Otherwise, both compounds significantly increase oxidative stress and the production of hydrogen peroxide and free hydroxyl radicals. The encapsulation of menthol and menthone in solid lipid nanoparticles (SLNs) demonstrated greater efficiency in reducing spore germination than in reducing mycelial growth. These results support the idea that menthol and menthone can act as sustainable antifungal agents and that their encapsulation in SLNs can be an important formulation tool to advance their application, but more studies are required to optimize and achieve more effective control.

Abstract BACKGROUND Drosophila suzukii is an invasive pest that causes major economic losses in berry production worldwide. Increasing concerns regarding insecticide resistance and environmental impacts associated with intensive insecticide use have stimulated interest in plant‐derived bioactive compounds as alternative sources of bioactive compounds for insect management. In this study, we evaluated the effects of isoquinoline alkaloids and alkaloid‐rich extracts from Berberis darwinii on oviposition and survival of D. suzukii under controlled laboratory conditions. RESULTS Alkaloidal extracts obtained from roots, stems, and leaves were evaluated together with berberine, palmatine, and their binary mixtures. Root extracts, characterized by high concentrations of berberine and palmatine, produced the strongest biological responses, reducing oviposition by more than 80% at the highest concentration and producing the lowest median lethal dose (LD₅₀) values across developmental stages (4.23 mg L −1 for eggs, 3.77 mg L −1 for larvae, and 0.50 mg L −1 for adults), compared with purified berberine (44.00, 83.14, and 7.03 mg L −1 , respectively). Palmatine also showed high larvicidal activity (LD₅₀ = 2.10 mg L −1 ), whereas leaf extracts exhibited comparatively weak biological activity consistent with their low alkaloid concentrations. Concentration‐dependent reductions in oviposition and increases in egg, larval, and adult mortality were consistently observed across treatments. CONCLUSION The results demonstrate that alkaloid‐rich extracts and protoberberine alkaloids from B. darwinii affect oviposition and survival across developmental stages of D. suzukii under laboratory conditions. Root extracts and palmatine‐rich treatments produced the strongest responses, highlighting the importance of tissue‐specific alkaloid accumulation in determining biological activity. These findings support further investigation of B. darwinii as a source of plant‐derived bioactive compounds affecting D. suzukii , although additional studies addressing environmental stability, non‐target effects, and field efficacy are required before practical pest management applications can be considered. © 2026 Society of Chemical Industry.

Haematobia irritans (L.), the Horn fly, is an obligate bloodsucking ectoparasite of cattle. This is an insect that lives on cattle dung during its early stages (egg, larva, and pupa), whereas in its adult stage, it develops an exclusively hematophagous diet. This lifestyle shift involves a significant adjustment in metabolic capacities and could exert considerable pressure on shaping the community of microorganisms associated with each developmental stage. In this work, we hypothesize that anaerobic microorganisms dominate the larval microbial communities, while aerobic microorganisms dominate the adult stage. To test this hypothesis, we performed an amplicon sequencing of the 16S rRNA gene analysis to describe the bacterial community across the Horn fly's life stages. We found that early stages, such as the egg and larva, were dominated by anaerobic Clostridiales and then transitioned to one overwhelmingly dominated by Gammaproteobacteria in adulthood. A notable decline in alpha biodiversity was observed during the pupal-to-adult transition, accompanied by considerable species turnover, indicating the existence of ecological filtering processes. We also estimated genera as part of the microbial core, as well as differentially abundant bacteria that may be relevant for development in both the larval and adult stages. These findings provide a clear picture of the microbial ecological succession processes associated with the bacterial symbionts of this important insect pest.

This study evaluated the photocatalytic activity of zinc oxide nanoparticles (ZnO-B) synthesized using a leaf extract of Aristotelia chilensis and the effect of calcination at different temperatures (400, 600, and 800 degrees C) on their properties and performance. The photocatalytic degradation of lignin was compared among biogenic ZnOB, chemically synthesized ZnO (ZnO-Ch), and commercial ZnO (ZnO-C). The lignin degradation rates after 24 h were ZnO-B_400 (60.8%), ZnO-B_600 (90.57%), ZnO-B_800 (27.83%), ZnO-Ch (23.2%), and ZnO-C (80.7%). The nanoparticles were characterized by TEM, XRD, FTIR, and UV-vis spectroscopy. The physicochemical properties and photocatalytic efficiency of ZnO-B were significantly influenced by calcination temperature, with ZnO-B_600 demonstrating superior photocatalytic activity under UV-A and simulated sunlight. GC-MS analysis of lignin degradation products revealed the transformation of lignin into high-value chemicals, including 2,3hexanediol, 1,2-benzenedicarboxylic acid diethyl ester, phthalic acid cyclobutyl isobutyl ester, 2-(1-oxopropyl)-benzoic acid, and 4-hydroxy-2-butanone. These findings highlight the potential of biogenic ZnO-B nanoparticles in photocatalytic processes for the valorization of Kraft lignin into value-added compounds of interest to the chemical, cosmetic, and pharmaceutical industries.

Araucaria araucana is one of the longest-living Chilean trees. Recently, Araucaria Leaf Damage disease, which causes damage to branches and crowns, was detected. Sinophloeus porteri, a bark beetle affecting A. araucana, could be associated with foliar damage. However, little is known about their ecological and chemical interactions. This study examined the olfactory response of S. porteri to volatiles emitted from A. araucana. Branches and weevils were collected from a national park, and volatiles were trapped from both healthy and unhealthy branches. Thirty terpenes were identified, some of which were reported for the first time in A. araucana. Healthy branches emitted large amounts of myrcene (>360 ng g−1 day−1), and unhealthy branches showed high hibaene emanations (>140 ng g−1 day−1). Olfactory assays verified that S. porteri was attracted to the volatile blends of branches, regardless of the health condition of the branches, but preferred the blend of unhealthy branches. Moreover, myrcene was repellent to these weevils, and hibaene acted as an attractant, suggesting that A. araucana might use myrcene for defense against S. porteri, and hibaene could stimulate host selection by beetles.

The horn fly is an economically important hematophagous ectoparasite of cattle. Its management relies heavily on broad-spectrum pesticides, which are harmful to the environment and have led to the development of resistance. Therefore, alternative control methods are needed. Semiochemicals involved in communication between horn flies and their host are a promising alternative. Considering that the egg-laying of this fly occurs almost exclusively in fresh cattle dung, and most parts of its life cycle occur totally in dung, dung volatiles might play an important role in horn fly behavior. Therefore, the main aim of this study was to evaluate the effects of volatile blends and compounds emitted from fresh/aged cattle dung on the olfactory response and oviposition of horn flies. Dung blends were captured and analyzed by SPME-GC/MS. p-Cresol was the most abundant compound in dung blends, followed by α- and β-pinene, limonene, and β-caryophyllene, among other common dung volatiles. Fresh-dung volatiles attracted males and females in a Y-tube olfactometer, and they elicited the egg-laying of flies in two-choice tests. p-Cresol and α-pinene were attractive to females and they elicited higher oviposition, demonstrating that dung volatile semiochemicals, in part, lend to dung attractiveness and stimulate the horn fly oviposition.

Despite the ethnobotanical significance of Chilean Colliguaja species, research on their biological activities and phytochemical composition remains limited. Among these species, Colliguaja odorifera Molina (Euphorbiaceae), traditionally used in folk medicine to alleviate toothaches, stands out for its potential for medicinal applications. This study aims to investigate the anti-inflammatory activity of the C. odorifera leaf extracts and their secondary metabolites isolated from the most active extract. A hydroalcoholic extract of C. odorifera leaves was prepared, and subsequently ethyl acetate (EA-E), n-butanol (B-E), and water (W-E) extracts were obtained by liquid–liquid partition. The extracts were first evaluated for their ability to inhibit lipoxygenase, and the most active extract was subsequently tested for hyaluronidase (HA) and secretory phospholipase A2 (sPLA2). The most active extract was EA-E, with IC50 values of 11.75, 31.09, and 6.60 µg/mL for anti-LOX activity, hyaluronidase, and sPLA2, respectively. This extract was analyzed by chromatography coupled to mass spectrometry and 1H and 13C NMR spectroscopy, allowing the identification, for the first time, of shikimic acid, gallic acid, methyl gallate, ethyl gallate, and a putative galloyl-luteolin. These results suggest that C. odorifera is a promising candidate for the development of natural alternatives to nonsteroidal anti-inflammatory drugs.

Botrytis cinerea is one of the phytopathogenic fungi of the greatest economic importance worldwide. Essential oils (EOs) have been proposed as a sustainable alternative to reduce the growth of phytopathogenic fungi. Nevertheless, few studies exist about its mechanisms of action. This study evaluated the antifungal activity of EOs from Citrus reticulata, Citrus limon, Citrus sinensis, and Citrus paradisi peels and their encapsulation inside solid lipid nanoparticles (SLNs). Accordingly, Citrus EOs were mainly constituted by monoterpene hydrocarbons, where limonene was the most abundant in all EOs. C. reticulata and C. limon EOs reduced the mycelial growth at above 54% after 96 h. The other EOs did not significantly impact the phytopathogen. C. reticulata EO increased the hyphae damage by 40%, but the spore germination was reduced by only 8.34%. It also significantly increased the pH, the electrical conductivity, and the release of intracellular absorbing material and soluble proteins in B. cinerea cultures. Contrary, the esterase, mitochondrial, and succinate dehydrogenase activities decreased at above 50%. C. reticulata EO into SLN reduced the mycelial growth of B. cinerea by 90-97%. These results show that the EO of C. reticulata alters the physiological and metabolic activities of B. cinerea to reduce its growth.

In recent years, RNA interference (RNAi) has become a widely studied tool for the functional analysis of genes and more recently, for pest control. Hylamorpha elegans (Coleoptera: Scarabaeidae) is a beetle endemic to Chile, considered an important pest during its larval stage as white grubs, feeding on organic matter (OM) and crop roots (e.g., wheat and red clover). Its control is limited due to its subterranean behavior. Thus, studying a chemosensory system as a fundamental part of the transport and recognition of chemicals from the environment could provide new targets for the knowledge and control of this beetle. Recently, chemosensory genes have been identified for H. elegans white grubs, and a chemosensory protein (CSP) was selected. This study aimed to evaluate the functional role of a highly expressed CSP in the subterranean behavior of white grubs. For this purpose, food preference assays were performed and standardized. Afterward, double-stranded RNA (dsRNA) was synthesized based on a selected CSP. A chosen preference assay was conducted using white grubs treated with dsRNA. Findings showed that white grubs prefer peat with high OM over red clover roots. Additionally, the CSP gene is upregulated when OM content increases. Finally, the knockdown of the CSP led to a disruption in soil-guided behavior. This protein may represent a novel target to be studied in the frame of management strategies for H. elegans.

The overuse of synthetic pesticides has triggered resistance in insect pests and caused severe environmental impacts, emphasizing the urgent need for sustainable alternatives in Integrated Pest Management (IPM). This study aimed to biosynthesize and characterize chitosan-coated silver nanoparticles (AgChNPs) using Galega officinalis leaf extract and evaluate their insecticidal effects against Drosophila suzukii (Diptera: Drosophilidae), a key pest of fruit crops worldwide. The biosynthesized AgChNPs (257.2 nm) were polydisperse, crystalline, and stable, as confirmed by UV-vis spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). AgChNPs exhibited strong toxicity across multiple developmental stages. Combined larvicidal and pupicidal activity reached 48.3% and 73.3% at 500 and 1000 ppm, respectively, significantly affecting immature stages. As a consequence, adult emergence declined to 46.7%, 51.7%, and 26.7% at 250, 500, and 1000 ppm. Among emerged adults, 71.7% displayed sublethal effects, with 62.8% showing morphological malformations (deformed wings, dehydration) and 37.2% presenting cuticle demelanization. Adulticidal bioassays revealed progressive mortality over 48 h, with 96% mortality at 1000 ppm. Overall, AgChNPs caused acute and chronic toxicity, reduced adult emergence, and induced severe morphological alterations, demonstrating their potential as a sustainable nanotechnological tool for effective pest control within IPM programs.

Domestication significantly altered the phenotypic and chemical traits of murtilla, notably reducing the emission of volatile compounds essential for plant–insect interactions. This reduction may affect the plant’s natural defense mechanisms, influencing its interactions with herbivores and predators. Therefore, this study tests whether domestication reduces volatile emissions in murtilla, increasing aphid preference and decreasing lacewing attraction. We selected wild ancestors (19-1, 22-1, and 23-2) from a longterm Ugni molinae germplasm bank. Crosses between these wild ancestors generated four first-generation domesticated ecotypes, 10-1, 16-16, 17-4, and 66-2, used in this study. These first-generation domesticated ecotypes were six years old at the time of the study and were used for comparisons in volatile profile and insect interaction analyses. The olfactometric preference index (OPI) for lacewing larvae and aphids revealed that wild ancestors attracted more predators than domesticated plants. For example, Ecotype 19-1 had an OPI of 1.64 for larvae and 1.49 for aphids, while Ecotype 10-1 showed lower attraction (OPI of 1.01 for larvae and 1.00 for aphids). Gas chromatography analysis identified differences in volatile organic compounds, with wild ancestor ecotypes emitting higher levels of compounds such as 2-hexanone, 1,8-cineole, and α-caryophyllene. Principal component analysis and hierarchical clustering confirmed these chemical distinctions. In olfactometer assays, lacewing larvae preferred α-caryophyllene and 2,4-dimethyl acetophenone, while aphids favored 2-hexanone and 3-hexanol. In Y-tube assays, lacewing adults showed strong attraction to α-pinene and 2,4-dimethyl acetophenone, with preferences increasing with concentration. These results indicate that domestication altered the volatile murtilla profile, reducing its attractiveness to natural predators while increasing its susceptibility to herbivores, supporting the plant domestication defense theory.

The Argentine stem weevil (ASW), a major pest in ryegrass pastures, causes significant agricultural losses. Ryegrass can establish a symbiotic association with Epichloë endophytic fungi, which supply chemical defenses, including peramine. This symbiosis helps protect ryegrass by providing peramine, which acts as a primary defense. In addition, ryegrass can activate induced defense mechanisms, with peramine remaining the central agent in response to herbivorous insect attacks. Therefore, this study assessed the feeding of the ASW on ryegrass carrying endophytic fungus and peramine levels in aerial organs and its effects on pest performance. Argentine stem weevil adults and larvae were placed on ryegrass leaves and stems to assess feeding. Two treatments were used: endophyte-free plants and endophyte-colonized plants. After ASW feeding damage, insect consumption was measured by the leaf area consumed. To evaluate peramine production and its increase in response to ASW attack, peramine levels in leaves were analyzed using liquid chromatography. Damaged E+ ryegrass plants showed significant increases in peramine, with adult and larval herbivory raising levels by 291% and 216% in stems and by 135% and 85% in leaves, respectively, compared to controls. Endophyte-free (E−) plants experienced more ASW damage, as insects preferred feeding on them, showing reduced activity as peramine levels rose in endophyte-infected (E+) plants. An oviposition assay confirmed insect preference for endophyte-free (E−) plants. Additionally, larvae reared on endophyte-infected (E+) plants had lower survival rates, correlating negatively with peramine levels. These results emphasize peramine’s role in strengthening ryegrass defenses against ASW, impacting both feeding and larval development.