Journal of Asia-pacific Entomology最新文献

{"title":"Post-exposure learned avoidance of the rice weevil, Sitophilus oryzae, to three entomopathogenic nematodes, Heterorhabditis bacteriophora isolates, and their efficacy and penetration rates on this insect","authors":"Alperen Kaan Bütüner,&nbsp;Eren Ergene,&nbsp;Osman Nuri Yaraşır,&nbsp;Guelika Kafando,&nbsp;Hilal Susurluk,&nbsp;Tufan Can Ulu,&nbsp;İsmail Alper Susurluk","doi":"10.1016/j.aspen.2026.102620","DOIUrl":"10.1016/j.aspen.2026.102620","url":null,"abstract":"<div><div>Entomopathogenic nematodes (EPNs) have gained considerable attention for their potential use in sustainable insect pest control strategies. The rice weevil, <em>Sitophilus oryzae</em> (L.) (Coleoptera: Curculionidae) is one of the most economically important stored-product pests worldwide. This study aimed to evaluate the penetration and insecticidal efficacy of three <em>Heterorhabditis bacteriophora</em> (Rhabditida: Heterorhabditidae) isolates (HB1138, HB4, and HBNL) against adult <em>S. oryzae</em>, and to assess the behavioural responses of surviving adults following EPN exposure. We hypothesized that prior exposure to EPNs would influence the subsequent orientation behaviour of surviving adults. Infective juveniles (IJs) of the isolates were applied to <em>S. oryzae</em> adults at eight concentrations (3–400 IJs/adult). Behavioural responses of adults surviving exposure to 400 IJs/adult were assessed using a three-chamber choice assay, in which previously exposed and non-exposed individuals were given simultaneous access to EPN-treated and untreated wheat. Adult mortality increased significantly with increasing IJ concentration, whereas no significant differences were detected among isolates. The highest mortality (66.67%) was recorded for HB1138 at 400 IJs/adult, and this isolate also exhibited the highest mean penetration rate (31.33 IJs/adult). Non-exposed individuals showed no preference between EPN-treated and untreated wheat, whereas previously exposed adults showed isolate-dependent behavioural responses. Insects previously exposed to HB4 showed a significantly higher probability of choosing EPN-treated wheat, whereas HB1138- and HBNL-exposed individuals consistently avoided EPN-treated wheat. Overall, <em>H. bacteriophora</em> isolates affected <em>S. oryzae</em> through both direct mortality and post-exposure behavioural responses, underscoring the need to consider sublethal effects in EPN-based biocontrol.</div></div>","PeriodicalId":15094,"journal":{"name":"Journal of Asia-pacific Entomology","volume":"29 3","pages":"Article 102620"},"PeriodicalIF":1.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148958648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Repellent efficacy of Citrus aurantifolia fruit peel essential oil aerosol against Aedes aegypti Linnaeus (Diptera: Culicidae) using a membrane feeding assay","authors":"Nabila Adlina Nasruddin,&nbsp;Nur Raihana Ithnin,&nbsp;Hidayatulfathi Othman,&nbsp;Zatul-'Iffah Abu Hasan,&nbsp;Norhanim Kamaruddin,&nbsp;Siti Farah Musa,&nbsp;Norashiqin Misni","doi":"10.1016/j.aspen.2026.102619","DOIUrl":"10.1016/j.aspen.2026.102619","url":null,"abstract":"<div><div>The increasing incidence of dengue necessitates effective and sustainable vector control strategies. Plant-derived Essential Oils (EOs) have emerged as promising alternatives to synthetic insecticides due to their biodegradability and multi-target bioactivity. This study aimed to characterise the chemical composition of <em>Citrus aurantifolia</em> Fruit Peel Essential Oil (CAFP-EO) and evaluate its repellent efficacy of its aerosol formulation against <em>Aedes aegypti</em> using a membrane feeding assay as an alternative to conventional human arm-in cage method. CAFP-EO was obtained via cold-press extraction and analysed using gas chromatography–mass spectrometry (GC–MS). Repellency was evaluated using an aerosol formulation containing 26.69% (<em>v</em>/v) CAFP-EO applied onto net cotton fabric and tested against adult female <em>Ae. aegypti</em> using a membrane feeding system. Repellent performance was compared with commercial synthetic-based product (DEET) and a natural commercial product found in the market. Observations were recorded over 4 h, and repellency (%) was calculated. Fabric characteristics were confirmed through burning test and Scanning Electron Microscopy (SEM). GC–MS analysis identified 30 compounds with <span>d</span>-limonene (22.27%), 1-propanol derivatives (17.18%), isopropyl myristate (16.07%), camphor (9.39%), benzoic acid (8.11%), 2-Propanol, 1,1′-oxybis- (5.92%), alpha-hexylcinnamaldehyde (5.65%), and linalool (2.61%) as major constituents. CAFP-EO aerosol showed high and sustained repellency (98.44%) up to 4 h, almost comparable to DEET-based product and superior to a natural commercial repellent. SEM confirmed effective EO deposition on cotton fibers. CAFP-EO demonstrated strong and sustained repellency against <em>Ae. aegypti</em>. The membrane feeding assay provides a reliable and reproducible alternative for repellency evaluation in vector control research, supporting the potential of CAFP-EO as an effective natural mosquito repellent.</div></div>","PeriodicalId":15094,"journal":{"name":"Journal of Asia-pacific Entomology","volume":"29 3","pages":"Article 102619"},"PeriodicalIF":1.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148958538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential of RNAi targeting β-N-acetylglucosaminidase(NAG1)for controlling Dendroctonus valens LeConte (Coleoptera: Scolytidae)","authors":"Yue Sun,&nbsp;Qin Cao,&nbsp;Yong-Hao Nan,&nbsp;Yang-Nan Hou,&nbsp;Chun-Fang Qi,&nbsp;Ji-Gang Li,&nbsp;Jian-Rong Wei","doi":"10.1016/j.aspen.2026.102608","DOIUrl":"10.1016/j.aspen.2026.102608","url":null,"abstract":"<div><div><em>Dendroctonus valens</em> (Coleoptera) is an invasive pest threatening pine forests in China. Long-term chemical application causes pest resistance and environmental pollution, highlighting the urgent need for environmentally friendly control strategies. A chitin degradation-related gene, <em>DvNAG1</em>, was screened based on genomic and transcriptomic data combined with eggNOG and KEGG annotations, and its potential as an RNAi target was evaluated. Phylogenetic analysis classified <em>DvNAG1</em> (encoding 594 amino acids) into the NAGs I group, clustering with coleopteran homologs. Spatiotemporal expression was examined by RT-qPCR, revealing significantly higher expression in adults than in eggs, and high expression in the Malpighian tubules and gut of fourth-instar larvae, while expression in the head and integument was almost undetectable. The dsRNA/SPc complex was delivered into fourth-instar larvae via integument permeation at 0.7 μg/larva. At this dose, silencing efficiency reached 90%, larval mortality reached 100%, pupation and emergence rates decreased, and pupal/adult malformations were observed. NAG enzyme activity was significantly reduced after <em>DvNAG1</em> silencing, whereas chitin content increased, suggesting that <em>DvNAG1</em> affects chitin metabolism and leads to larval death. RNAi results demonstrate that <em>DvNAG1</em> is essential for growth and development of <em>D. valens</em> larvae. Taken together, these results indicated that silencing <em>DvNAG1</em> not only increases larval mortality and malformation rates but also disrupts pupation and emergence. Understanding the function of <em>DvNAG1</em> in <em>D. valens</em> can provide new insights for developing innovative strategies to control <em>D. valens</em>.</div></div>","PeriodicalId":15094,"journal":{"name":"Journal of Asia-pacific Entomology","volume":"29 3","pages":"Article 102608"},"PeriodicalIF":1.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148854410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Parasitoids of the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), in Thailand: diversity and parasitism rates across five regions","authors":"Kasem Kongnirundonsuk,&nbsp;Supatcharee Tanasarnpaiboon,&nbsp;Sirikul Pethuan,&nbsp;Kittipum Chansri,&nbsp;Pornthap Kerkig,&nbsp;Buntika Areekul Butcher,&nbsp;Nakorn Pradit","doi":"10.1016/j.aspen.2026.102621","DOIUrl":"10.1016/j.aspen.2026.102621","url":null,"abstract":"<div><div>The fall armyworm (FAW), <em>Spodoptera frugiperda</em> (J.E. Smith) (Lepidoptera: Noctuidae), has been established in Thailand since 2018 and threatens maize production. Information on indigenous FAW parasitoids in Thailand remains limited. This study surveyed FAW parasitoids across five major regions of Thailand (November 2023–March 2024). Of 47 maize fields inspected across 12 provinces, 20 fields yielded larvae; 631 FAW larvae were examined by rearing and dissection, and 50 egg masses were collected opportunistically from 10 sites. Overall larval parasitism was 5.23% (33/631 larvae), highest in the North region (18.0%); site-level rates (0–26.3%) should be interpreted cautiously given small, uneven sample sizes. Egg mass parasitism was 10.0% (5/50), restricted to a single site in Lamphun Province, indicating a localized rather than regionally representative pattern. COI barcoding and Maximum Likelihood phylogenetic analysis identified four parasitoid taxa: the larval parasitoids <em>Chelonus</em> sp. and <em>Microplitis</em> sp. (Hymenoptera: Braconidae), and the egg parasitoids <em>Telenomus remus</em> Nixon (Platygastridae) and <em>Trichogramma chilonis</em> Ishii (Trichogrammatidae). Morphological examination of reared adults identified <em>Chelonus</em> sp. as <em>Chelonus formosanus</em> Sonan, whereas <em>Microplitis</em> sp. specimens were consistent with both <em>M. manilae</em> and <em>M. prodeniae</em>, precluding species-level resolution by morphology alone. <em>Chelonus formosanus</em> was the most widely distributed taxon, recorded across four regions with site-level parasitism reaching 26.3%. An unidentified larval parasitoid was recovered by dissection but could not be identified due to failed COI amplification. These results provide baseline data on FAW parasitoid diversity and parasitism rates in Thailand, supporting further evaluation of insecticide use and conservation biological control within FAW integrated pest management.</div></div>","PeriodicalId":15094,"journal":{"name":"Journal of Asia-pacific Entomology","volume":"29 3","pages":"Article 102621"},"PeriodicalIF":1.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148958539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic diversity and cryptic species structure of Bemisia tabaci in Türkiye","authors":"Ömer Yüzer,&nbsp;Ersin Doğaç,&nbsp;Alper Tonguç","doi":"10.1016/j.aspen.2026.102622","DOIUrl":"10.1016/j.aspen.2026.102622","url":null,"abstract":"<div><div><em>Bemisia tabaci</em> is one of the most harmful insect pests worldwide and represents a complex of cryptic species with distinct ecological traits, making regular monitoring essential for effective management. In this study, the genetic diversity and distribution of <em>B. tabaci</em> cryptic species in the Aegean and Mediterranean regions of Türkiye were analysed using the mtCOI gene. Two cryptic species, MEAM1 and MED, were identified, with the MED cryptic species comprising the Q1 and Q2 mitochondrial lineages. MEAM1 was dominant overall; MED Q1 was detected in İzmir, Aydın and Adana, whereas MED Q2 was detected in Muğla, Antalya and Adana. MED Q1 was predominant in western provinces and was also detected farther south, whereas MEAM1 was more prevalent in Mediterranean provinces such as Adana and Mersin. A total of 32 haplotypes were detected, including 11 study-specific haplotypes that were not represented among the GenBank sequences included in the comparative analyses. Cryptic species-specific analyses revealed substantially higher mitochondrial genetic diversity in MED than in MEAM1. Statistical analyses revealed a significant association between cryptic species distribution and host plants. MEAM1 was mainly associated with vegetable hosts, while MED lineages were more common in cotton. Phylogenetic analyses showed close relationships between Turkish and Eastern Mediterranean populations, indicating shared mitochondrial lineages among these populations. These findings emphasize the importance of cryptic species-based approaches for effective pest management.</div></div>","PeriodicalId":15094,"journal":{"name":"Journal of Asia-pacific Entomology","volume":"29 3","pages":"Article 102622"},"PeriodicalIF":1.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148958646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrative analyses of lipidomics and transcriptomics provide insights into host lipid regulation by Scleroderma sichuanensis (Hymenoptera: Bethylidae) venom","authors":"Long Liu,&nbsp;Hua Yang","doi":"10.1016/j.aspen.2026.102614","DOIUrl":"10.1016/j.aspen.2026.102614","url":null,"abstract":"<div><div>Parasitoid wasps comprise an ecologically vital of insects capable of modulating host metabolic processes to benefit the successful development of their progeny. Parasitoid venoms act as maternally produced virulence determinants that are essential for this process. Despite the well-established roles of lipids in membrane organization, energy homeostasis and cellular signaling, the molecular basis of parasitoid venom-induced modulation of host lipid metabolism remains poorly understood. Here, liquid chromatography-mass spectrometry (LC-MS) together with RNA sequencing (RNA-seq) was employed to examine the effects of <em>Scleroderma sichuanensis</em> venom on lipidomic or transcriptome profiles of its host, <em>Tenebrio molitor</em>. Lipidomic analysis showed that <em>S. sichuanensis</em> venom induced dramatic alterations in both the content and composition of host lipid classes. Totally, 251 significantly different lipids were detected, among which glycerophospholipids and glycerolipids were the most abundant, comprising 149 and 65 species, respectively. Notably, venom induced significant accumulation of glycerolipid and membrane remodeling by altering glycerophospholipid composition. Transcriptomic profiling also revealed that venom modulated genes and pathways associated with lipid metabolism, with 327 genes significantly upregulated and 222 genes significantly downregulated, mainly enriched in glycerolipid biosynthesis and glycerophospholipid metabolism. This study provides new evidence for venom-mediated regulation of host lipid metabolism and sheds light on parasitoid-host coevolutionary interactions.</div></div>","PeriodicalId":15094,"journal":{"name":"Journal of Asia-pacific Entomology","volume":"29 3","pages":"Article 102614"},"PeriodicalIF":1.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148854440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insecticidal potential of Korean Tanacetum cinerariifolium extracts: Identification of 3,5-Dicaffeoylquinic acid as a key synergist","authors":"Ka Hee Cho,&nbsp;Jeong Yong Cho,&nbsp;Jang Hoon Lee,&nbsp;Do-Ik Kim,&nbsp;Young Cheol Kim","doi":"10.1016/j.aspen.2026.102618","DOIUrl":"10.1016/j.aspen.2026.102618","url":null,"abstract":"<div><div>The overuse of synthetic insecticides has accelerated the search for eco-friendly botanical alternatives. This study investigated the insecticidal efficacy and phytochemical composition of ethanol extracts prepared separately from the flowers or leaves of Korean-grown <em>Tanacetum cinerariifolium</em> (var. Dalmatian) compared with an imported commercial pyrethrum formulation (1.1% pyrethrins, ICE). Extracts were obtained in 95% ethanol (40 °C, 4 weeks), and their pyrethrin esters and phenolic constituents were quantified by liquid chromatography–mass spectrometry. Insecticidal activity was assessed by the dose-response curves in leaf-disc bioassays against <em>Myzus persicae</em>, <em>Tetranychus urticae</em>, <em>Frankliniella occidentalis</em>, and <em>Plutella xylostella</em>. The Korean Dalmatian flower (KDF) and leaf (KDL) extracts demonstrated superior insecticidal efficacy based on LC₉₀ values for total pyrethrins across all tested pest species. The LC₉₀ values for KDF and KDL were 2.7 and 7.8 mg/L, respectively, which were lower than 67.6 mg/L for the ICE. Phytochemical profiling identified 3,5-dicaffeoylquinic acid (3,5-DCQA) in KDF (36.7%) and KDL (8.5%, relative peak area), but not in the ICE. An authentic 3,5-DCQA standard exhibited dose-dependent insecticidal activity (LC₅₀ = 132 mg/L). Most notably, co-application of 3,5-DCQA and pyrethrins at their respective LC₅₀ values killed 90% of insects, versus 48–55% for each compound alone. These findings indicate that the efficacy of the Korean pyrethrum extracts was driven by synergism between pyrethrins and co-extracted phenolics such as 3,5-DCQA, validating domestically cultivated Korean pyrethrum as an effective, eco-friendly agent for sustainable pest management.</div></div>","PeriodicalId":15094,"journal":{"name":"Journal of Asia-pacific Entomology","volume":"29 3","pages":"Article 102618"},"PeriodicalIF":1.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148958540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of an enhanced baculovirus expression vector based on p10 promoter combinations","authors":"Hyuk-Jin Moon,&nbsp;Hyo-Gyeong Jang,&nbsp;Soo-Dong Woo","doi":"10.1016/j.aspen.2026.102617","DOIUrl":"10.1016/j.aspen.2026.102617","url":null,"abstract":"<div><div>The baculovirus expression system (BES) is widely used for recombinant protein production. However, its reliance on very late viral promoters such as <em>p10</em> and <em>polyhedrin</em> (<em>polh</em>) imposes temporal limitations that can compromise protein yield and quality due to virus-induced cell death. In this study, a novel <em>p10</em> promoter-based overexpression vector was developed to enhance recombinant protein production while addressing these intrinsic limitations. To enable earlier production and enhance transcriptional activity, additional viral promoters and homologous region (hr) transcriptional enhancers were systematically combined upstream of the <em>p10</em> promoter. Among the tested constructs, a synergistic combination of the hr5 sequence and the <em>p6.9</em> promoter significantly enhanced protein expression, resulting in a 1.9-fold increase compared with the conventional <em>p10</em> promoter alone. These results indicate that the newly developed <em>p10</em>-based overexpression vector is an effective and versatile tool for improving recombinant protein production in BES by enabling higher expression levels.</div></div>","PeriodicalId":15094,"journal":{"name":"Journal of Asia-pacific Entomology","volume":"29 3","pages":"Article 102617"},"PeriodicalIF":1.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148854438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transcriptomic analysis reveals candidate genes associated with egg-laying capacity in two honey bee subspecies (Apis mellifera mellifera and Apis mellifera ligustica)","authors":"Lu-Xia Pan,&nbsp;Shi-Qing Zhong,&nbsp;Qing-Sheng Niu,&nbsp;Xiang-Shi Huang,&nbsp;Zhi-Yong Liu,&nbsp;Zhi-Jiang Zeng","doi":"10.1016/j.aspen.2026.102616","DOIUrl":"10.1016/j.aspen.2026.102616","url":null,"abstract":"<div><div><em>Apis mellifera ligustica</em> and <em>Apis mellifera mellifera</em> are two important honey bee subspecies widely kept and studied. But their queens differ greatly in egg-laying capacity. To better understand the mechanisms of this difference, ovarian transcriptomic differences between the two subspecies were analyzed using Illumina sequencing technology. A total of 180 common differentially expressed genes (DEGs) were identified, with 61 up-regulated and 119 down-regulated in <em>A. m. ligustica</em> relative to <em>A. m. mellifera</em> queens. Among these, four candidate DEGs related to oocyte maturation, ovarian development, and sperm storage were identified, such as <em>vg</em>, <em>spr</em>, <em>oocyte zinc finger protein</em> and <em>SPATA6.</em> Moreover, candidate genes exhibited alternative splicing divergence between the two subspecies, with more diverse splicing patterns being observed in <em>A. m. ligustica</em>. This study provides valuable gene expression data for elucidating fecundity differences between two honey bee subspecies.</div></div>","PeriodicalId":15094,"journal":{"name":"Journal of Asia-pacific Entomology","volume":"29 3","pages":"Article 102616"},"PeriodicalIF":1.5,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148854439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemotype-dependent larvicidal activity of clove, cinnamon, and marjoram essential oils against Culex pipiens: biochemical and molecular insights","authors":"Hanan Salman Alyahya ,&nbsp;Habeeb M. Al-Solami ,&nbsp;Wafa Mohammed Al-Otaibi ,&nbsp;Akram S. Alghamdi ,&nbsp;Mohammad M. Aljameeli ,&nbsp;Ahmed S. Hashem ,&nbsp;Jazem A. Mahyoub","doi":"10.1016/j.aspen.2026.102571","DOIUrl":"10.1016/j.aspen.2026.102571","url":null,"abstract":"<div><div>Botanical larvicides are increasingly investigated as environmentally compatible alternatives for mosquito control. In the present study, we evaluated the larvicidal activity of clove, cinnamon, and marjoram essential oils against <em>Culex pipiens</em> larvae and linked oil chemotype to biochemical, histopathological, and molecular responses. GC–MS profiling revealed distinct chemotypes dominated by eugenol in clove oil, (E)-cinnamaldehyde in cinnamon oil, and <em>trans</em>-sabinene hydrate in marjoram oil. Across 150–500 ppm, all oils produced concentration-dependent larval mortality, with clove oil showing the highest potency. Regression-derived overall LC₅₀ values were 280.7, 319.4, and 358.5 ppm for clove, marjoram, and cinnamon, respectively, while the corresponding LC₉₀ values were 491.3, 554.6, and 608.5 ppm. Time-course analysis further indicated that clove LC₅₀ declined from approximately 281.3 ppm on day 1 to 233.7 ppm on day 3. Acute knockdown after 30 min followed the same rank order, with clove (≈85.9%) &gt; marjoram (≈73.0%) &gt; cinnamon (≈62.4%), while the solvent control showed no effect. At LC₅₀-equivalent exposure, larvae exhibited marked suppression of GST, AChE, CAT, and SOD activities, accompanied by elevated MDA levels, indicating disruption of detoxification and redox homeostasis. Histopathological analysis revealed clear midgut epithelial damage in treated larvae, with the most severe changes observed after clove-oil exposure. Multivariate analysis separated the oils according to their integrated biological and biochemical effects and identified GST activity as the strongest discriminating variable (canonical loading =  − 0.94; canonical r = 0.92; <em>P</em> &lt; 0.001). Consistently, molecular docking supported favorable interactions of major oil constituents within the GST binding pocket, particularly for clove-associated ligands. Collectively, these findings indicate that the larvicidal activity of these essential oils is chemotype-dependent and involves coordinated disruption of detoxification capacity, oxidative balance, and midgut integrity in <em>C. pipiens</em> larvae.</div></div>","PeriodicalId":15094,"journal":{"name":"Journal of Asia-pacific Entomology","volume":"29 2","pages":"Article 102571"},"PeriodicalIF":1.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148167596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}