Search Results (447)

Essential oils obtained from Siparuna plants, e.g., S. guianensis and S. gesnerioides, have potential for use as biorational insecticides. However, the activities of S. gesnerioides oils remain largely unexplored compared to S. guianensis oils. Using an integrative approach combining toxicological bioassays, geometric morphometrics, and in silico modeling, we assessed the adulticidal potential, selectivity, and the effects of early-life exposure to these oils on the larval susceptibility and adult wing morphometry of Aedes aegypti. Adulticidal assays revealed high toxicity, with S. guianensis (LC₅₀ = 15.0 nL/mL) being 15-fold more potent than S. gesnerioides (LC₅₀ = 233.0 nL/mL). Beyond acute lethality, early-life (i.e., eggs to L2 larvae) exposure to sublethal concentrations (S. guianensis = 7.4 nL/mL and S. gesnerioides = 118.0 nL/mL) was associated with wing morphometric disruptions and increased fluctuating asymmetry in Ae. aegypti adults, especially in those exposed to S. gesnerioides essential oil. Furthermore, early-life exposure to S. gesnerioides modulated L4 larvae susceptibility, which was associated with lower mortality in subsequent exposures. Selectivity assays demonstrated low acute oral toxicity in initial laboratory screenings with Apis mellifera, while molecular docking approaches predicted higher affinity of bicyclogermacrene and α-copaene for Ae. aegypti TRPV channels. Collectively, while S. gesnerioides oil was less acutely toxic, early-life sublethal exposures reduced fourth instar larvae (L4) susceptibility, which may have contributed to developmental instability and morphological alterations in adults. Our findings highlight the potential of Siparuna essential oils in mosquito management by impacting mosquito fitness beyond acute mortality. Full article

Megalurothrips usitatus is a major pest of cowpea in tropical regions, where frequent insecticide use has promoted the development of resistance. In this study, field populations of M. usitatus were collected from five major cowpea-producing areas in Hainan from 2023 to 2025, and their susceptibility to five commonly used insecticides was evaluated using a modified leaf-tube residual film method. Resistance levels varied among regions and insecticides, with southern populations generally showing higher LC₅₀ values than central and northern populations. The tested neonicotinoid insecticide, acetamiprid, showed the highest resistance levels. By 2025, the resistance ratios of the Ledong, Sanya, and Lingshui populations to acetamiprid reached 298.48-, 139.60-, and 130.25-fold, respectively. Spinosyn resistance also increased rapidly, particularly in southern Hainan. The resistance ratio to spinetoram reached 110.78-fold in the Ledong population, while resistance to spinosad reached 37.06-fold in the Lingshui population. However, the absolute LC₅₀ values of spinosad and spinetoram remained relatively low compared with those of acetamiprid and chlorfenapyr, indicating that these two spinosyn insecticides retained relatively high bioassay activity in laboratory bioassays. A significant positive correlation was detected between the LC₅₀ values of spinosad and spinetoram across field populations (r = 0.8972, p < 0.0001), suggesting cross-resistance within the spinosyn class. These results indicate that resistance management for M. usitatus in Hainan should prioritize reducing the use of high-resistance-risk insecticides, avoiding consecutive applications of spinosyns, and designing region-specific rotation programs based on local resistance monitoring. Full article

The melon fly, Zeugodacus cucurbitae (Coquillett), is a globally significant agricultural pest causing substantial economic losses. Odorant-binding proteins (OBPs) are critical of the insect olfactory system, yet their specific physiological functions in Z. cucurbitae remain largely uncharacterized. In this study, we functionally characterized ZcucOBP14 and investigated its putative involvement in host chemoreception and insecticide tolerance. Sequence alignment and phylogenetic analysis indicated that ZcucOBP14 belongs to the Minus-C OBP subfamily, and quantitative reverse transcription PCR (RT-qPCR) showed that it was predominantly expressed in both the head and abdomen. Fluorescence binding assays revealed that ZcucOBP14 exhibited broad binding affinity to 11 host plant volatiles, three sex pheromones, and two insecticides. Subsequent electroantennography (EAG) and behavioral bioassays identified isopulegol, 1-hexanol, linalool, and α-pinene as key ligands regulating the behavioral responses of Z. cucurbitae. RNA interference (RNAi)-mediated knockdown of ZcucOBP14 significantly reduced EAG responses to key ligands, eliminated behavioral preference, and increased insecticide-induced mortality by 20%. Molecular docking further identified that Tyr71, Ile67, Trp50, Val107, Phe116 and Leu70 were critical residues involved in ligand interactions. Collectively, these findings highlight the indispensable role of ZcucOBP14 in olfactory perception and its contribution to insecticide tolerance, laying a solid theoretical foundation for the development of novel behavior-modifying agents, attractants, and optimized integrated pest management (IPM) strategies against this pest. Full article

The growing demand for natural, safe, and sustainable bioactive compounds has sparked interest in indigenous essential oils (EOs) for their antimicrobial, antioxidant, and therapeutic properties. Their practical applications are often limited by poor solubility, volatility, and susceptibility to degradation when exposed to light, heat, and or oxygen. The literature lacks exploration of the indigenous EOs in nanoencapsulation studies. Using nanosystems and carriers, the oil can be delivered to targeted areas over a longer period. This is useful for various applications, including biopesticides, regenerative medicine, gene therapy, textiles, and antimicrobial coatings. Studies reveal that nanoencapsulated EOs exhibit higher insecticidal and antimicrobial activity than free oil. In this review, we observed that Lippia javanica is the most used EO in nanoencapsulation processes. This may be attributed to its broad spectrum of biological activities and its wide distribution in South Africa. This review examines the applications of selected nanoencapsulated indigenous EOs of the Eastern Cape province in medicine, food, and agriculture. The findings underscore the potential of nanoencapsulation to transform indigenous EOs into multifunctional agents that can support health, food security, and sustainable agricultural practices, while calling for further research on safety, regulatory frameworks, and commercialization pathways. Full article

The rice stem borer (RSB), Chilo suppressalis, is one of the most destructive rice pests in China and chlorantraniliprole has been extensively used for its control over the past decade. However, the continuous and intensive application of chlorantraniliprole has accelerated the development of resistant RSB populations in field, thereby threatening sustainable rice production. In this study, a field resistant strain of RSB exhibited a 181.76-fold resistance level to chlorantraniliprole compared to a susceptible strain. To explore the potential involvement of ATP-binding cassette (ABC) transporters in chlorantraniliprole resistance, four candidate ABC transporter genes (CsABCC1, CsABCC3, CsABCA3 and CsABCD2) were analyzed in resistant and susceptible strains. Compared to the susceptible strain, the expressional levels of CsABCC1 and CsABCC3 were significantly upregulated by 1.58- and 1.38-fold, respectively, whereas of CsABCA3 and CsABCD2 showed non-significant differences in the resistant strain. RNA interference assays demonstrated that naked dsRNA induced only limited gene silencing, while chitosan-mediated dsRNA delivery significantly improved RNAi efficiency. Following feeding with chitosan-coated dsCsABCC1 and dsCsABCC3, the expression levels of both genes were reduced by 44.63% and 38.49%, respectively, relative to the control and the larval mortality increased following chlorantraniliprole treatment to 63.33% and 56.67%, respectively. In addition, silencing CsABCC1 caused a greater reduction in larval weight after insecticide treatment. These findings indicated that CsABCC1 and CsABCC3 are involved in chlorantraniliprole detoxification and may contribute to resistance. Overall, this study provides evidence for the functional involvement of ABC transporters in chlorantraniliprole resistance and highlights chitosan-mediated RNAi as a promising complementary approach for resistance management within integrated pest management programs. Full article

Athetis lepigone (Möschler) is an important pest of maize in North China, whose larvae feed mainly on maize leaves, stems, and roots during the seedling stage, with conventional maize lacking effective resistance to it. In recent years, transgenic Bt maize expressing Cry1Ab and Vip3Aa proteins has been commercialized in China; however, its resistance against A. lepigone has not yet been systematically evaluated. In this study, three Bt maize events, DBN3601T expressing Cry1Ab and Vip3Aa, DBN9936 expressing Cry1Ab, and DBN9501 expressing Vip3Aa, were used to comprehensively assess resistance against the pest based on Bt protein expression levels in different maize tissues, larval susceptibility across instars, and larval feeding behavior under controlled laboratory conditions. The results showed that Bt protein expression varied significantly among maize tissues commonly fed upon by the insect, following the general pattern: seedling leaf > stem > root. Bioassays using artificial diets incorporated with freeze-dried maize leaf powder indicated that larvae were significantly more susceptible to Cry1Ab than to Vip3Aa, with LC₅₀ values of 1.05 and 2.65 μg·g⁻¹, respectively. Maize co-expressing both proteins exhibited high insecticidal activity. First-instar larvae displayed feeding avoidance of Bt maize tissues, and early instars were more sensitive than later instars; however, stems and roots showed stronger toxicity to older larvae. In simulated field infestation assays, the control efficacies of DBN3601T, DBN9936, and DBN9501 reached 94.35%, 88.79%, and 10.56%, respectively, at five days post-infestation. Overall, DBN3601T maize exhibited a strong resistance performance against A. lepigone, indicating strong potential for pest management applications. Full article

Bradysia odoriphaga is a devastating soil pest of Allium tuberosum (Chinese chive), and current control relies heavily on chemical insecticides. Cry39Ab1 toxins from Bacillus thuringiensis (Bt), which are highly toxic to B. odoriphaga, offer an environmentally friendly alternative. However, its mechanism of action remains unclear. In this study, we identified the involvement of vacuolar H⁺-ATPase subunit A (V-ATPase A) in Cry39Ab1 insecticidal activities. The full-length cDNA sequences of BoV-ATPase A was contained 1659 bp open reading frame (ORF), encoding a protein of 552 amino acids with a calculated molecular weight of 59 kDa and an isoelectric point of 9.11. Successful expression and purification of BoV-ATPase A (with GST and His tags) and Cry39Ab1 (with GST and His tags) proteins were achieved. GST pull-down assays demonstrated a direct interaction between recombinant BoV-ATPase A and activated Cry39Ab1 toxin in vitro. Heterologous expression of BoV-ATPase A in Cry-insensitive Sf9 cells conferred susceptibility to Cry39Ab1, resulting in a significant increase in cytolysis compared with control cells. Finally, RNAi-mediated knockdown of BoV-ATPase A in larvae significantly decreased their susceptibility to Cry39Ab1, as evidenced by a marked decrease in mortality. This is the first report that BoV-ATPase A is a key protein required for Cry39Ab1 toxicity, revealing its insecticidal mechanism and establishing BoV-ATPase A as a potential target for pest control. Full article

The Colorado potato beetle, Leptinotarsa decemlineata, is a major insect pest of potatoes. Our previous studies have demonstrated that two cytochrome P450 monooxygenase (P450s) genes, CYP9Z140 and CYP9AY1, and a uridine diphosphate–glycosyltransferase (UGT) gene, UGT321AP1, play important roles in thiamethoxam resistance to L. decemlineata. However, the related upstream regulatory mechanism remains unclear. In this study, we first monitored the resistance of L. decemlineata field populations to thiamethoxam in Xinjiang to determine the resistance ratios. The predicted results demonstrated that four transcription factors (TFs), CncC/Maf, Abd-B, FoxO, and Ptx1, may bind to the core regions of three gene promoters. The qRT-PCR results revealed that the TFs were significantly upregulated by thiamethoxam and exhibited specific spatiotemporal expression patterns. Dual-luciferase reporter assays indicated that the CncC pathway could regulate the expression of three detoxification genes, whereas Abd-B and FoxO only regulate CYP9Z140 and UGT321AP1 expressions, respectively. Ptx1 could regulate the expression of both CYP9AY1 and UGT321AP1. Furthermore, knockdown of several TFs through RNA interference significantly reduced expression of the corresponding detoxification genes, consistent with the dual-luciferase reporter assay results, and increased the thiamethoxam susceptibility of test adults. These findings aid in gaining a deeper understanding of the transcriptional regulation mechanisms of insecticide resistance in insects. Full article

Flower thrips are a major vegetable and crop pest in Inner Mongolia, China. Due to the frequent application of insecticides for pest control, insecticide resistance in the species has been reported previously. Therefore, we evaluated the field variation in four populations due to the use of spinosoid insecticides, spinosad and spinetoram, by assessing stomach and contact toxicities. The LC₅₀ value of the stomach toxicity for the DLT population for spinosad and spinetoram was 1.22–2.25 and 1.19–1.90-fold higher, respectively, compared with values in the other three populations. The LC₉₉ value of stomach toxicity for the QBM population for spinosad was 9.22–161.57-fold higher compared with the other three populations, whereas the value for spinetoram in the HHG population was 3.28–6.77-fold higher compared with the other three populations. These results clearly showed that the field variation due to spinosoid insecticide use differed across the region. For spinosad, the LC₉₉ values for stomach toxicity were higher than those for contact toxicity in all four populations, with action ratios ranging from 0.031 to 0.448. In contrast, for spinetoram, the LC₉₉ values for stomach toxicity were lower than those for contact toxicity in all populations, with action ratios ranging from 52.64 to 1901.21. Sequence analysis of the FIα6 subunit of the nAChRα6 gene revealed no point mutations in any of the four populations. Therefore, we further investigated the activity of the detoxification enzyme, CYP450s, by analyzing the synergistic effect of piperonyl butoxide (PBO) on the different susceptibilities to spinosad in the populations. The LC₉₉ value of spinosad was reduced 59.64-fold in the PBO-treated DLT population and 2.52-fold in the PBO-treated HLG population compared with the untreated population. These results clearly indicate that the field variation in flower thrips due to spinosoid insecticides in Inner Mongolia, China, may be due to the activation of the detoxification enzyme, CYP450s. Full article

Control of resistant mosquito populations may be approached by the development of novel synergists to improve the performance of already commercialized compounds. Extracts of black pepper (Piper nigrum), Cha Plu (Piper sarmentosum), and Sichuan pepper (Zanthoxylum spp.) synergized natural pyrethrins applied topically to Aedes aegypti females. Both black pepper and Sichuan pepper extracts synergized natural pyrethrins over 13-fold. Synergism was also observed directly on the mosquito larval central nervous system (CNS), suggesting this effect is an important contributing factor distinct from that of reduced metabolism. Piperine, from black pepper, and α-hydroxysanshool (α-HS) from Sichuan pepper, synergized natural pyrethrins on susceptible CNS, but only piperine was capable of synergizing natural pyrethrins on the CNS of a pyrethroid-resistant strain of Ae. aegypti, indicating that these molecules may possess slightly different mechanisms of action or binding sensitivities. These results demonstrate that pepper alkamides are capable of enhancing select insecticidal chemistries via target-site synergism, a novel mechanism of synergism that might be important for enhancing future insecticidal formulations. Full article

The increasing prevalence of insecticide resistance in Aedes aegypti threatens the effectiveness of chemical vector control and highlights the need for alternative approaches targeting mosquito behavior. This study evaluated the oviposition deterrent and larvicidal activity of Salvia munzii essential oil against insecticide-susceptible (New Orleans; NO) and insecticide-resistant (Escobedo) Ae. aegypti strains. The essential oil, dominated by camphor (29.6%), 1,8-cineole (20.8%), and limonene (16.7%), was assessed through laboratory and semi-field bioassays. Larvicidal activity yielded LC₅₀ values of 184.38 µg mL⁻¹ for the susceptible strain and 305.04 µg mL⁻¹ for the resistant strain, with a resistance ratio of 1.65, indicating susceptibility. Oviposition deterrence was quantified using the Oviposition Activity Index (OAI), and median repellent concentrations (RC₅₀) were estimated. Under laboratory conditions, RC₅₀ values were 1.65 µg mL⁻¹ for the NO strain and 1.73 µg mL⁻¹ for the Escobedo strain. Under semi-field conditions, the RC₅₀ for the Escobedo strain decreased to 0.62 µg mL⁻¹. Deterrent activity increased with concentration and persisted for up to 40 days, particularly at higher doses. These results demonstrate that S. munzii essential oil exhibits both larvicidal and oviposition deterrent activity against Ae. aegypti, including a pyrethroid-resistant population, under laboratory and semi-field conditions. The findings support further evaluation of S. munzii essential oil as a potential complementary tool for integrated vector management strategies. Full article

The tomato borer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a highly destructive invasive pest of tomato, and its ability to develop resistance to insecticides is well known. The susceptibility of three field populations from Egypt (Luxor, Assuit, and Giza) to the insecticides chlorantraniliprole, chlorfenapyr, indoxacarb, emamectin benzoate, and spinetoram was evaluated by leaf-dip bioassays. The second-instar larvae were exposed, and mortality was noted 24, 48, and 72 h later. Probit analysis was used to calculate lethal concentrations (LC₅₀ and LC₉₀) and resistance ratios (RR₅₀). Furthermore, key detoxification enzymes (α-esterases, cytochrome P450 monooxygenases, and glutathione S-transferases) were also measured to identify possible metabolic resistance mechanisms. Considerable inter-population differences were observed. Detoxification enzymes (α-esterases, cytochrome P450 monooxygenases, and glutathione S-transferases) were measured. The Luxor population showed the highest LC₅₀ values and resistance ratios, especially to chlorfenapyr and indoxacarb, suggesting low-to-moderate resistance, while the Giza population was the most susceptible. Emamectin benzoate and spinetoram provided excellent control of all laboratory and field strains. Full article

Spotted-wing Drosophila (Drosophila suzukii), an economically important invasive but widely distributed pest, has developed resistance to multiple insecticide classes, threatening its management in commercial soft fruit production. This study evaluated the synergism of piperonyl butoxide (PBO) with zeta-cypermethrin in two field-collected resistant California populations and a susceptible population with bioassays. Female flies from the two resistant populations exhibited 55-fold and 25-fold resistance, respectively, compared to the susceptible population. PBO co-application significantly enhanced insecticide efficacy in both resistant populations, with synergism ratios of 6.51 and 4.06. However, complete susceptibility at label rates of the insecticide was not restored, indicating that other resistance mechanisms may also be present in these populations. PBO–pyrethroid combinations show promise for improving field efficacy against resistant populations, though they should be integrated with insecticide rotation and other integrated pest management tactics for sustainable resistance management. Full article

Background/Objectives: As a traditional Chinese medicinal herb, Cnidii Fructus is widely used in clinical practice. Its volatile organic compounds (VOCs) are closely related to its antipruritic effect and insecticidal properties. Due to the susceptibility of this medicinal herb to mold contamination, adopting appropriate sterilization measures is of great significance for its storage. ⁶⁰Co irradiation is widely used for this purpose due to its various advantages. Methods: This study employed Gas Chromatography–Ion Mobility Spectrometry (GC-IMS) combined with multivariate statistical analysis to systematically investigate the influence of different ⁶⁰Co irradiation doses (0, 3, 6, 9 kGy) on the VOCs of Cnidii Fructus and associated metabolic regulatory mechanisms. Results: A total of 115 VOCs were tentatively identified. Statistical analysis revealed dose-dependent effects: 3 kGy irradiation caused the least compositional perturbation, best preserving original chemical characteristics; 6 kGy induced more pronounced compositional changes; and 9 kGy triggered substantial chemical composition reconstruction. Differential metabolite enrichment analysis indicated that medium and high doses of irradiation primarily perturbed central carbon metabolic pathways, including pyruvate metabolism, glycolysis/gluconeogenesis, and glyoxylate and dicarboxylate metabolism. Key differential components were tentatively identified (e.g., α-Thujone, α-Pinene, β-Pinene) that possess pharmacological activities closely associated with the traditional efficacy of Cnidii Fructus. Conclusions: When the irradiation dose is 3 kGy, the VOCs profile of Cnidii Fructus is most similar to that of the non-irradiated control group, suggesting that its compositional profile may be closer to that of traditional high-quality medicinal materials. Meanwhile, the differential metabolites and core metabolic pathways identified in this study can provide a chemical reference for the quality control of irradiated Cnidii Fructus. The findings provide a theoretical basis and technical support for the rational application of ⁶⁰Co irradiation sterilization in the processing of Chinese medicinal materials and their powders. Full article

Endocrine-disrupting chemicals (EDCs) are a diverse group of environmental pollutants capable of interfering with hormonal and immune system regulation. In recent years, increasing concern has been raised about the effects of chemicals, including bisphenols, phthalates, per- and polyfluoroalkyl substances (PFAS), insecticides, and parabens, on maternal and fetal health, primarily due to their widespread exposure in human populations. Pregnancy represents a critical window characterized by tightly regulated hormonal and immunological adaptations. Emerging evidence suggests that EDC exposure during this period may alter maternal microbiota, disrupt immune responses, and interfere with endocrine signaling. These changes may increase susceptibility to bacterial and viral infections, including bacterial vaginosis, urinary tract infections, and intrauterine infections, all of which are associated with adverse pregnancy outcomes. This review summarizes the current evidence on the sources and mechanisms of exposure to endocrine disruptors during pregnancy and examines the potential biological pathways linking endocrine disruption to the development of infections. Particular emphasis is placed on the interactions between immune regulation, hormonal signaling, and changes in the microbiome, which may contribute to increased susceptibility to infections. A deeper understanding of these complex mechanisms is critical to improve risk assessment, develop effective public health strategies, and ultimately protect maternal and fetal health in an environment of increasing chemical exposure. A literature search was conducted using PubMed/MEDLINE, Scopus, and Web of Science, including studies published up to January 2026. Full article