Search Results (4,243)

The two-spot cotton leafhopper (TSCL), Amrasca biguttula (Hemiptera: Cicadellidae), is an emerging invasive pest in the southeastern United States. Although TSCL has historically been associated with cotton and vegetable crops, recent detections on ornamental hibiscus have raised regulatory concern, including “Stop Sale and Hold” orders and an emergency quarantine in Texas. Despite increasing pressure on hibiscus, no insecticide efficacy data exist for ornamental systems. We evaluated the acute (0–24 h) and residual (24–96 h) toxicity of bifenthrin, flupyradifurone, and tolfenpyrad against adult and immature TSCL using a sequential-cohort leaf-disc bioassay. New insects were introduced at 24 h and 72 h to isolate residue-based mortality from prolonged exposure effects. Bifenthrin caused the highest acute mortality at 24 h, whereas flupyradifurone and tolfenpyrad exhibited slower initial activity but strong residual performance. Immatures were more susceptible than adults across all doses. By 72 h, all three insecticides produced near-complete mortality, with significant treatment and dose effects confirmed by ANOVA and binomial GLM analyses. Dose–response curves showed steep concentration-dependent mortality for bifenthrin and tolfenpyrad and a time-dependent response for flupyradifurone. These results provide the first insecticide efficacy data for TSCL on ornamental hibiscus and offer immediate guidance for nursery producers and regulatory agencies. The findings establish a foundation for whole-plant and greenhouse evaluations to support integrated management and interstate plant-movement compliance. Full article

Cyflumetofen (CYF) and its main metabolite, trifluoromethyl benzoic acid (B-1), both of which contain a trifluoromethyl group, are increasingly used in agriculture due to their high stability and efficacy. Structurally, these molecules share several physicochemical features with per- and polyfluoroalkyl substances (PFASs), including endocrine disruption and reproductive toxicity. This study aims to evaluate the reproductive toxicity effects of CYF and its metabolites using adult zebrafish as a model organism. The results indicate that exposure to CYF and B-1 at environmentally relevant concentrations for 21 days causes hormonal disruption and abnormal gonadal development in fish; moreover, as the concentrations increase, CYF and B-1 significantly impair the reproductive capacity of zebrafish and lead to developmental abnormalities in their offspring. Based on the ratio of E2/T and the alteration of key genes in the HPG axis, such as cyp17a2 and cyp11c1, it is hypothesized that CYF and B-1 disrupt hormonal homeostasis via the HPG axis. Notably, male fish were more susceptible when exposed to CYF or B-1, exhibiting sex-specific differences. RNA-seq analysis revealed that CYF/B-1 promotes Ca²⁺ release from the zebrafish brain and induces steroid hormone dysregulation based on the HPG axis via genes such as hsd17a and gnrh. In summary, this study provides key insights into the reproductive toxicity of CYF and its major metabolite, highlighting their risks to the environment and human health. Full article

Temperature and humidity are critical abiotic factors shaping the survival and adaptation of insect pests. However, the molecular mechanisms underlying high-temperature tolerance under contrasting humidity conditions remain poorly understood, particularly in globally invasive species such as the tomato pinworm, Tuta absoluta. Previous studies have examined individual stressors, leaving interactive thermo-hygrometric effects on gene expression and survival insufficiently resolved. Here, we assessed the contribution of cytochrome P450 genes to thermal adaptation under low- and high-humidity conditions using transcriptome profiling combined with nanocarrier-mediated RNA interference (RNAi). Third-instar larvae were exposed to high temperature under low humidity (HT-LH: 40 °C, 50% RH) or high humidity (HT-HH: 40 °C, 75% RH) for eight hours. Survival declined from 97.5% in the control to 74.16% under HT-LH and 68.33% under HT-HH conditions. Transcriptome analysis revealed extensive differential gene expression, with 464 genes upregulated and 565 downregulated in HT-LH, and 1145 upregulated and 1166 downregulated in HT-HH. Functional annotation highlighted pathways linked to metabolic regulation, proteostasis, and detoxification, including multiple cytochrome P450-associated processes. RT-qPCR confirmed the upregulation (3–5 fold) of four P450 genes (CYP6AB327, CYP6ABF1b, CYP6AE214, and CYP9A306c) under high temperature across both humidity regimes. RNAi-mediated silencing of these genes significantly reduced larval survival, demonstrating their functional role in thermal-hygrometric stress tolerance across. Cytochrome P450 genes underpin the adaptive capacity of the tomato pinworm to high-temperature stress across contrasting humidity conditions, highlighting RNAi-based disruption of P450 function as a promising avenue for sustainable pest management under climate change scenarios. Full article

Cyantraniliprole, a second-generation diamide insecticide, exhibits broad-spectrum efficacy against numerous insect pests due to its selective activation of insect ryanodine receptors (RyRs). This activation triggers uncontrolled calcium release from the sarcoplasmic reticulum, resulting in sustained muscle contraction, paralysis, and ultimately death. Its unique mode of action, which is different from that of organophosphates, carbamates, pyrethroids, and neonicotinoids, helps minimize cross-resistance, making it a valuable component of integrated pest management (IPM). However, continuous field use has led to the development of resistance, primarily mediated by target-site mutations within the RyR transmembrane domain (e.g., G4946E, I4743M, and I4790K) and by enhanced metabolic detoxification via cytochrome P450 monooxygenases, carboxylesterases, and glutathione S-transferases. These mechanisms often confer cross-resistance to other diamide insecticides, thereby complicating resistance management. Moreover, sublethal exposures can disrupt insect growth, development, and reproduction, potentially accelerating resistance evolution. In addition, cyantraniliprole poses ecological risks due to its toxicity to non-target organisms such as aquatic species, including zebrafish and water fleas, pollinators such as honeybees, and soil fauna, as well as the environmental persistence of its major metabolite, J9Z38. This review comprehensively integrated current knowledge on the molecular mechanisms of action, genetic and metabolic bases of resistance, sublethal effects, and ecotoxicological impacts of cyantraniliprole, along with its environmental fate, plant uptake and translocation, and residue dynamics in agricultural systems. Finally, we discuss potential risk-mitigation strategies, including formulation optimization, application-method improvements, and resistance monitoring. Overall, this review aims to provide a comprehensive scientific foundation for the sustainable use, resistance management, and regulatory assessment of this widely used insecticide. Full article

Diapause is a vital overwintering strategy for many insects, yet its comprehensive molecular architecture remains elusive. In the polyphagous pest Helicoverpa armigera, facultative pupal diapause is key to its ecological success. To elucidate the complex diapause regulatory network, we conducted a transcriptomic analysis of diapause (DP) versus non-diapause (NP) pupal brains across early pupal development (days 2, 5, and 10). Integrated analyses, including differential expression, persistent gene identification, weighted gene co-expression network analysis (WGCNA), and multiscale embedded network analysis (MEGENA), were employed to define core regulatory modules and hubs. The number of differentially expressed genes (DEGs) increased over time, with 1781 genes persistently regulated across all time points, enriched in mitochondrial metabolism, hormone signaling, and chromatin remodeling. WGCNA revealed a diapause-associated module (red) linked to RNA processing/transcription and a development-associated module (blue) enriched for translation and mitochondrial metabolism. Network analyses pinpointed three central hub genes: DDX5 and PLK4 (downregulated in diapause, upregulated upon 20E treatment) and TAF5L (upregulated in diapause, downregulated after 20E). This study provides a systems-level view of the transcriptional landscape governing pupal diapause in H. armigera and identifies novel candidate regulators for future functional studies. Full article

The artificially modified Bacillus thuringiensis (Bt) protein can target lepidopteran pests, and planting genetically modified crops with insect-resistant traits is environmentally friendly. However, it is still uncertain whether the exogenous insect-resistant proteins in genetically modified crops will affect the soil rhizosphere microorganisms. This study utilized 16S rDNA sequencing technology to analyze the rhizosphere soil of insect-resistant genetically modified corn LD05 and its control variety Zheng58 at five developmental stages: before sowing, seedling stage, jointing stage, silk emergence stage, and maturity stage. Each sample was taken with six biological replicates, resulting in a total of 60 sequencing samples, with an average of 4368 OTUs obtained per sample. Both alpha and beta analyses showed that LD05 and Zheng58 did not have a significant impact on the soil rhizosphere microbial community. The developmental stage rather than the variety was the main factor causing differences in the bacterial community. Overall, there was no significant difference in the bacterial diversity between the insect-resistant genetically modified corn LD05 and its control variety Zheng58. The results provide useful information for understanding the impact of genetically modified crops on soil microbial communities and also provide a theoretical basis for the safety evaluation of LD05. Full article

Hypoxia-inducible factor (HIF) is recognized as a key transcription factor via regulating a variety of molecular responses to hypoxia, although the details are still unclear. In this study, based on bioinformatics analysis, the expression of the HIF-1α gene in T. castaneum (TcHIF-1α) under hypoxic treatments was determined. After TcHIF-1α knockdown by injecting dsRNA, larval mortality, the expression levels of oxidative stress-related genes, and enzymatic activities were measured; DNA damage was also evaluated through single cell gel electrophoresis. The result indicated that TcHIF-1α is highly conserved in structure. TcHIF-1α exhibited distinct temporal patterns, with a peak after 72 h of exposure to 2% O₂. Following TcHIF-1α knockdown, a significant increase in larval mortality (17.44 ± 5.91%) and moderate DNA damage level was found. This might be accompanied by ROS accumulation, lipid peroxidation (LPO), and suppression of antioxidant enzymatic activities. The expression of genes involved in ROS synthesis (e.g., NOX) was significantly upregulated, whereas genes responsible for mitigating oxidative stress (e.g., OGG1, XRCC1, PARP1, SOD1a) were markedly downregulated. These findings elucidate the critical role of HIF-1α in insect hypoxia adaptation by regulating the antioxidative stress, highlighting its potential as a promising target for developing novel pest control strategies. Full article

The soybean pod borer, Leguminivora glycinivorella, is a monophagous pest that threatens soybean production. Its larvae feed concealed within pods, which limits the efficacy of conventional insecticides. Elucidating its chemosensory system is therefore essential for developing green, behavior-based management strategies. Reference-based transcriptomics across multiple tissues of L. glycinivorella identified a comprehensive repertoire of chemosensory genes, including 76 odorant receptors (ORs), 15 gustatory receptors (GRs), 18 ionotropic receptors (IRs), 52 odorant-binding proteins (OBPs), 18 chemosensory proteins (CSPs), and 4 sensory neuron membrane proteins (SNMPs). Sequence and phylogenetic analyses characterized these candidates within the context of known insect chemosensory families. Notably, canonical bitter GRs and specific IR lineages (e.g., IR100/IR85a) were not detected in our dataset, potentially reflecting adaptation to the specialized soybean-feeding habit of this pest. Expression profiling further revealed pronounced sexual and tissue dimorphism: male antennae showed significant enrichment of putative pheromone receptors (PRs) and LglySNMP1, whereas several OBPs and ORs exhibited female-biased expression, suggesting roles in host location and oviposition. Additionally, the high expression of GR43a homologs points to fructose sensing, while the lack of detectable CO₂ receptor components (except LglyGR2) suggests atypical carbon dioxide perception mechanisms. Collectively, this study provides a valuable expression atlas of chemosensory genes in L. glycinivorella and identifies sex-specific candidate genes for future functional validation and behavior-based pest management. Full article

The bollworm/corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), is one of the most economically damaging crop pests in North America. Colonies of H. zea are notoriously difficult to maintain and frequently collapse in laboratory rearing. The persistent difficulty in maintaining healthy H. zea colonies has become a major obstacle to performing many research activities on the insect. To optimize colony maintenance, six populations were evaluated across three trials and six tests examining pupal maturity at diet removal, adult emergence synchrony, and cohort size at mating and reproduction. Females emerging from mature pupae produced more eggs than those from mid-aged (5–7 d) or young pupae (0–2 d). Synchronizing male and female emergence within one day yielded higher mating frequency, spermatophore transfer, and progeny, whereas a two-day difference reduced these metrics by 45–67%. Adult cohort size also influenced the outcomes, with ≥10 males and ≥10 females per cage enhancing reproductive success. Most matings occurred on nights 2–3, peaking within 2.5 h after lights off. Positive correlations were observed among mating frequency, spermatophore transfer, and progeny production. Overall, optimal performance was achieved by removing pupae only at maturity, synchronizing adult emergence within one day, and maintaining larger adult cohorts. These findings should establish key conditions to improve the mating success, reproduction, and laboratory rearing of H. zea. Full article

Apple is one of the most important fruits worldwide; in addition, it constitutes nearly 60% of Hungary’s total fruit production. Presently, the challenge in pest management is not only the decreased range of pesticides, but also the deeper knowledge of natural enemies occurring in fruit plantations, and in their neighborhood. Our objective was to study how season, year, orchard structure, and varieties influence the occurrence of insect pest damage and beneficial insects in apple. We also investigated the strength of correlations between pest damage and natural enemies, as well as among the different natural enemy taxa. The experiment was conducted in three apple orchards, and the damage of insect pests and the number of natural enemies were monitored across ten trees/varieties/sectors/dates. All sites were managed according to integrated pest management (IPM) guidelines, and no unmanaged or untreated control plots were included. Significant differences were observed among orchards and years for all taxa, except Cydia pomonella (L.) among orchards and Orius spp. among years. Pest populations are primarily driven by seasonal and climatic factors, while beneficial insects are shaped more by local habitat features and orchard structure. No effect of the varieties on insect damage could be detected, whereas the abundance of beneficial organisms differed significantly among varieties in more cases. The weak correlations between pests and their natural enemies suggest that the presence and activity of predators depend not only on pest abundance but also on other interrelated ecological factors in intensive apple orchards. The damage caused by C. pomonella could also be kept at a low level in all orchards when appropriate pest management technology is applied. Full article

The predatory bug Arma custos (Hemiptera: Pentatomidae) is a natural enemy insect capable of preying on over 40 types of agricultural and forestry pests. Here, we describe the characteristics of the morphology and ultrastructure of its venom apparatus visualized using light and electron microscopy. Light microscopy revealed that the venom apparatus of A. custos consists of a pair of main gland and tubular accessory gland. The main gland consist of two lobes, the anterior main gland (AMG) and posterior main gland (PMG). Between the two lobes of the main gland, there is a strong constriction, characterizing a hilum (Hi) where two separate ducts, the venom duct of the main gland (VD) and the duct connecting the accessory gland to the main gland (AMD), are inserted. The VD extends toward the head and connects to the venom pump (VP), while the AMD extends toward the thorax and connects to the accessory gland (AG). Ultrastructural examination of the venom glands reveals that the AMG and PMG consist of a layer of cubic or spherical glandular cells forming a large circular lumen, while the AG exhibits two narrow lumens. The secretory cytoplasm of AMG, PMG, and AG contains a well-developed rough endoplasmic reticulum, along with mitochondria, nuclei, secretory vesicles, autophagosomes, and secretory granules. However, significant differences exist in the ultrastructural characteristics among the three glands. Unlike glandular secretory cells in the venom glands, the ultrastructure of VD, and AMD reveals only well-developed nuclei, mitochondria, and elaborate plasma membrane folds. These results indicate that venom proteins are synthesized and stored by the AMG, PMG, and AG, while the VD and AMD ducts are responsible for transporting the venom. Full article

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), poses a significant threat to global tomato production. However, environmentally sustainable management strategies for this pest, as well as its mechanisms of insecticide resistance, remain insufficiently understood. Broflanilide, a novel meta-diamide compound, can bind specifically to the transmembrane domain of the RDL subunit, causing prolonged opening of the chloride channel, disruption of neurotransmission, and ultimately insect paralysis and death. This study employed the leaf immersion method to conduct bioassays on the second-instar larvae of T. absoluta to evaluate physiological responses to sublethal concentrations of the novel amide insecticide broflanilide. Subsequently, high-throughput transcriptome sequencing was performed to investigate changes in gene expression and metabolic pathways. Bioassay results determined the larval sublethal concentrations of broflanilide to be 0.136 mg/L (LC₁₀) and 0.210 mg/L (LC₃₀). Sublethal exposure significantly prolonged the larval period, reduced pupal weight, and inhibited fecundity of female adults. Transcriptomic and qPCR analyses revealed that, compared with the control (CK), expression of the vitellogenin gene Vg decreased by 15.99% and 30.27% under LC₁₀ and LC₃₀ treatments, respectively, while its receptor gene VgR decreased by 11.56% and 24.49%. Similarly, expression of chitin synthase genes chs1 and chs2 declined by 13.56% and 30.17% (chs1), and 7.85% and 19.45% (chs2), respectively. Gene expression analysis elucidated how sublethal insecticides treatment impact larval development and fecundity. Furthermore, the study revealed upregulation of cytochrome P450-mediated detoxification pathways and Toll/Imd immune signaling pathways under broflanilide stress, indicating activation of a coordinated defense response in T. absoluta. Sublethal broflanilide exposure modulated larval gene expression to balance growth, development, and stress adaptation. Such exposure exerts selective pressure on susceptible populations, potentially driving adaptive shifts in detoxification metabolism and contributing to the development of field resistance. These findings advance our understanding of the sublethal effects of novel insecticides and provide valuable insights for insecticide deployment strategies and resistance management. Full article

Nematodes in the genus Oscheius (Rhabditidae) have traditionally been regarded as free-living bacteriophagous or necromenic associates of insects. Over the past two decades, however, multiple Oscheius species and isolates have been shown to express facultative pathogenicity toward insects and, in some cases, parasitism of mollusks. This has stimulated interest in Oscheius as a complementary group of biological control agents that may function under conditions limiting classical entomopathogenic nematodes (EPNs) of the genera Steinernema and Heterorhabditis. Here, we synthesize current knowledge on Oscheius taxonomy and diversity, life-history strategies, bacterial associations and virulence mechanisms, evidence for control of insect and mollusk pests, and recent advances in chemo-ecology relevant to host finding. We emphasize that Oscheius represents a continuum of ecological strategies, and we adopt conservative terminology in which “entomopathogenic” is reserved for Oscheius species/isolates that meet operational criteria of insect pathogenicity. Finally, we highlight key barriers to wider implementation—strain variability, bacterial partner instability, non-target and community effects, and production/quality control needs—and propose research priorities for the development of robust, field-reliable Oscheius-based biocontrol. Full article

As a result of global climate change, insects are increasingly being exposed to extreme temperature events; yet population-level variation in heat tolerance and its underlying mechanisms remain poorly understood. In this study, we investigated thermal adaptation in four geographically distinct populations of the invasive mealybug Dysmicoccus neobrevipes from southern China. The populations were subjected to acute heat stress across a gradient of temperatures where survival, fecundity, offspring viability, and sex ratio were quantified. We found pronounced geographic divergence in upper thermal limits: populations from warmer regions (Guangdong and Hainan) exhibited better survival, more stable reproductive output, and greater tolerance in offspring compared with populations from cooler regions (Guangxi and Yunnan). Thermal responses followed a nonlinear pattern, with moderate heat often enhancing performance, while temperatures above physiological thresholds triggered abrupt declines. Under heat stress, life-history strategies differed among populations, with some exhibiting stress-induced reproductive investment and others showing vulnerability across all traits. Importantly, acute heat exposure produced cross-generational effects, highlighting that parental thermal history can influence offspring performance. These results demonstrate that population-specific climatic adaptation, nonlinear physiological limits, and life-history trade-offs jointly shape thermal tolerance. Understanding these mechanisms provides a predictive framework for anticipating invasive pest expansion under future climatic warming and informs region-specific pest management strategy development. Full article