BACKGROUND:Effectively harnessing the biocontrol potential of parasitic wasps requires a precise understanding of their interspecific competition and parasitic efficacy. RESULTS:Using the three dominant egg parasitoids of the fall armyworm (FAW; Spodoptera frugiperda)-Trichogramma dendrolimi, Trichogramma chilonis and Telenomus remus (Te. remus)-as a model system, we first analyzed the parasitic competitive relationships, developed an ITS2-based molecular assay for species-specific identification, and then applied this method to analyze the parasitoids' competitive interactions and quantify their parasitic potential. Competition assays demonstrated that Te. remus achieved superior parasitism performance and produced more progeny with its higher female ratio. Furthermore, we established exponential regression models, which accurately correlated ITS2 gene expression levels with parasitism rates, enabling a direct molecular assessment of parasitic activity. Using these models, we quantified the parasitism rates on FAW eggs as 70.25% for Te. remus, significantly higher than the 41.54% for T. dendrolimi and 36.45% for T. chilonis. CONCLUSION:This research not only provided clear evidence prioritizing Te. remus as a highly effective agent for FAW biocontrol, but also developed a molecular approach for rapid and accuracy parasitoid efficacy assessment contributing to sustainable pest management. © 2026 Society of Chemical Industry.

Abstract Aphid alarm pheromone, ( E )‐β‐farnesene (EβF), is a key chemical signal responding to predation threats, inducing alarm, escape, and wing differentiation in conspecifics. Beyond facilitating intraspecific communication, EβF also modulates interactions with natural enemies, playing a crucial role in defense. This review explores the chemical composition, biosynthesis pathways, release dynamics, and molecular perception mechanisms of EβF. Furthermore, we discuss its potential applications in pest management, including transgenic traits, slow‐release formulations, and synergistic deployment with plant‐derived enhancers (e.g., methyl salicylate). However, the incorporation of EβF into integrated pest management encounters several challenges, such as high volatility, environmental instability, and aphid adaptability. Future research should focus on optimizing slow‐release technologies, developing multifunctional EβF analogs, integrating gene editing and precision release strategies, and adopting interdisciplinary approaches to improve EβF stability and efficacy.

Traditionally, the control of Sitobion avenae (Fabricius) relies heavily on chemical insecticides; however, the long-term use of chemical insecticides has caused hazards to the environment and human health. Eugenol and cinnamaldehyde are important active components of plant essential oils. In this study, the toxicity of these two compounds against S. avenae was determined via fumigation and contact bioassays, and repellent activity tests were conducted to clarify their control effects. The results showed that the contact KD50 values of eugenol and cinnamaldehyde against S. avenae through cuticular penetration were 0.25 μL/mL and 0.11 μL/mL, respectively (applied onto a treated surface area of 30 cm2 per replicate), while their fumigant KD50 values were 7.04 μL/mL and 2.55 μL/mL, respectively (tested in a sealed 125 mL glass vial). Both compounds exhibited repellent activity. At a concentration of 0.75 μL/mL, the repellency rate of cinnamaldehyde was 24.4%, while that of eugenol was 15.6%. However, both compounds displayed a certain attractive effect at the lowest concentration of 0.375 μL/mL. These findings demonstrate that eugenol and cinnamaldehyde exhibit high insecticidal activity against the wheat aphid under laboratory conditions, with dose-dependent repellency and toxicity in simple laboratory assays.

The diamondback moth (Plutella xylostella) represents a formidable challenge in agriculture due to its rapid reproductive cycle and increasing resistance to conventional insecticides. This study investigates the regulation of sex pheromone biosynthesis in P. xylostella, focusing on the role of the neuropeptide pheromone biosynthesis activating neuropeptide (PBAN) and its downstream signaling pathways. Through transcriptomic analysis, we identified key genes involved in pheromone production, including the PBAN receptor (PBANR), calcineurin (CaN), and acetyl-CoA carboxylase (ACC). Further investigation was carried out to examine the effects of avermectin, a naturally derived insecticide, on both the pheromone biosynthesis and mating success of P. xylostella. Our findings reveal that sublethal doses of avermectin significantly disrupt pheromone production, caused by a reduction in extracellular calcium influx, as well as decreased activity of enzymatic pathways crucial for pheromone synthesis. Additionally, the mating success of both F0 and F1 generations was adversely affected, indicating transgenerational impacts of chemical exposure. This study provides new insights into the biochemical pathways regulating sex pheromone production in P. xylostella and highlights the intricate effects of avermectin on pest behavior and population dynamics, contributing to the development of sustainable agricultural practices.

The English green aphid, Sitobion avenae, a major pest of wheat, exhibits classical wing dimorphism. To support research and data sharing on the molecular basis of this trait, we generated full-length transcriptomes from three different developmental stages of winged and wingless morphs using PacBio SMRT and Illumina HiSeq sequencing platforms. The dataset comprises 2,309,013 circular consensus sequences (CCSs), with 85.29% identified as full-length non-chimeric reads (FLNC) reads after filtering. Approximately 282 Gb of PacBio subreads were obtained, with a total of 125,495,799 reads. Functional annotation was performed for 43,219 transcripts (44.3%). Across the developmental stages, differential expression analyses revealed numerous genes with varied expression patterns, with 71 genes identified as potential regulators of wing polymorphism. These candidates are associated with biological processes such as wing development, hormone biosynthesis, energy metabolism, and cell death pathways. This dataset provides a comprehensive molecular resource for investigating the transcriptional basis of wing polyphenism in aphids and may offer insights applicable to other insect systems.

The rose-grain aphid, Metopolophium dirhodum (Walker), has been identified as a predominant aphid species in wheat agroecosystems. Flonicamid, a novel pyridinamide insect growth regulator, has demonstrated high efficacy against various sap-sucking pests. We investigated the sublethal and intergenerational effects of flonicamid on M. dirhodum using life table analysis. We found that flonicamid had a certain degree of acute toxicity to M. dirhodum. Exposure to sublethal concentrations of flonicamid (LC15 and LC35) significantly reduced adult longevity, reproductive duration, and fecundity in the F0 generation of M. dirhodum. Moreover, these sublethal concentrations adversely affected the F1 generation, decreasing fecundity and altering key life table parameters, including adult longevity, total longevity, reproductive period, adult pre-reproductive period, nymph production per female, age-stage-specific survival rate (sxj), intrinsic rate of increase (r), net reproductive rate (R0), and finite rate of increase (λ). Population projections further demonstrated a significant decline in the total population size of M. dirhodum under sublethal flonicamid exposure compared to the control. These findings demonstrate that flonicamid exerts adverse sublethal and intergenerational effects on M. dirhodum, ultimately suppressing its population growth. The study outcomes provide valuable evidence for evaluating flonicamid’s overall pesticidal potential and enhancing integrated pest management protocols for wheat aphid control.

(E)-β-farnesene (EβF), a sesquiterpene widely recognized for its role in aphid alarm signaling, triggers escape behaviors and influences aphid population dynamics. Despite its potential as a biological control agent, the effects of EβF on the English grain aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae), a major wheat pest, remain insufficiently explored. In this study, we topically applied EβF at a concentration gradient (10 to 1,000 ng/μl) to various developmental stages of S. avenae and assessed their behavioral responses, development, reproduction, and winged offspring ratio under different population densities. Our results revealed that EβF at 10 ng/μl induced significant behavioral changes, including leg shaking, fast walking, and falling from host plants, across all developmental stages. Exposure to 200 ng/μl EβF significantly reduced fecundity by 19.6% and shortened lifespan by 17.8%, while increasing the proportion of winged offspring by 19.8%, particularly under low parental density combined with high offspring density. Field trials further revealed that a higher concentration of EβF (1,000 ng/μl) led to a 25% increase in the proportion of winged offspring compared to controls, with environmental factors such as population density influencing the response. These findings confirm the insecticidal and density-dependent effects of EβF on S. avenae, with transgenerational impacts on wing dimorphism, highlighting its potential for the sustainable aphid control in wheat ecosystems.

Wheat aphids, including Sitobion miscanthi (Takahashi) and Rhopalosiphum padi (Linnaeus), inflict serious damage to wheat crops. Consequently, it is necessary to find a new management option to reduce the damage caused by aphids. Entomopathogenic fungi serve as a tool to control the aphid population build-up. The current study explores a new entomopathogenic fungus that, infests S. miscanthi in China. Using morphological and molecular methods, the isolated colonies were identified as Beauveria brongniartii Sacc. (Petc) (Ascomycota: Cordycypitaceae). Bioassay studies with purified conidial suspensions further confirmed the infectivity to the adult wheat aphids. The results showed that after 6 days of treatment with a conidia concentration of 1.0 x 107 spores/mL, the mortality rates of S. miscanti and R. padi were 97.78 % and 91.11 %, respectively. However, 52.22 % of S. miscanthi and 47.78 % of R. padi adults survived after 7 days of exposure to a conidia concentration of 1.0 x 103 spores/mL of B. brongniartii. Additionally, the semi-lethal time decreased with the increase of conidia concentration of the strain. To further understand and enhance the value of B. brongniartii, we performed whole-genome sequencing and an analysis of its strain. The genome length was 2,295,663,102 bp and 316 contigs, with an average length of 7,264,756.71 bp. Moreover, database alignment identified 455 CAZyme, 1643 TCDB, and 2850 PHI genes. The current study also explored five surface proteins of B. brongniartii Y618 that worked best against wheat aphids. To our knowledge, this is the first report of the pathogenicity of B. brongniartii against wheat aphids, and it could serve as a potential candidate for an integrated pest management plan.

Nucleopolyhedroviruses (NPVs) are widely used agents for the biological control of Lepidoptera pests. The gut bacterial community of insects plays crucial roles in their biological activities; however, the interaction between NPV and the gut bacterial community in Lepidoptera pests remains largely unexplored. In this study, we found that the diversity and composition of Spodoptera littoralis larvae mid-gut bacteria were significantly altered by a diet containing the antibiotic streptomycin. At all four examined taxonomic levels, the abundance of the dominant native mid-gut bacterial taxa decreased in larvae fed on the streptomycin diet. Biomarker analysis revealed that Enterococcaceae and Enterococcus were significantly enriched in larvae on the control diet. However, Bacteroidetes and Bacteroidales were the differentially abundant taxa in larvae on the streptomycin diet. In the bioassays with 2 × 104, and 1 × 105 NPV OBs/larva, the significantly higher relative dose of NPV was detected in the S. littoralis larvae fed on the streptomycin diet than the ones fed on control diet. Furthermore, subjected to the infection of 1 × 105 NPV OBs/larva, the lifespan of S. littoralis larvae fed on the streptomycin diet (5.78 ± 0.08) were significantly shorten than the ones fed on control diet (6.099 ± 0.08). These findings suggest that the native mid-gut bacterial community of S. littoralis likely plays a role in resistance to NPV, and alterations in its composition may facilitate NPV propagation, increasing NPV susceptibility. Thus, disrupting the native mid-gut bacterial community may represent a novel strategy for controlling S. littoralis using NPV.

Insect growth regulators (IGRs) face limitations of slow action and high dosage, while RNA pesticides are constrained by the scarcity of effective RNAi targets. Here, we propose a standardized strategy to develop multicomponent nanopesticides by combining IGRs with RNA pesticides via a co-delivery nanoplatform. The star polycation (SPc) nanocarriers and diflubenzuron (DFB) were assembled into nanoscale DFB/SPc complexes, enhancing toxicity against green peach aphids by disrupting chitin biosynthesis. RNA-seq analysis identified chitin synthase (CHS) as a synergistic RNAi target. The hpCHS/SPc complex effectively silenced CHS, inducing more than 50% aphid mortality. Co-loading dsCHS and DFB produced stable nanoparticles with improved leaf adhesion, plant uptake, aphid cuticle contact, and translocation, achieving up to 82.2% mortality at only LC20 of free DFB. This work establishes a generalizable, scalable approach for designing multicomponent nanopesticides with high efficacy and low dosage for sustainable pest control.

The investigation of genetics-based biopesticides has become a central focus in pesticide studies due to their inherent advantages, including species specificity, environmental safety, and a wide range of target genes. In this study, a mixture of miR-184 agomir and nanomaterial star polycation (SPc) was used to treat the nymphs of the English grain aphid, Sitobion avenae (F.). The life parameters of the aphids at various developmental stages were analyzed using an age–stage two-sex life table to assess the effect of miR-184 agomir on the experimental population. The results indicated that miR-184 agomir had a significant negative effect on four key life parameters, including the intrinsic rate of increase, the finite rate of increase, the net rate of increase, and the mean generation time. The population prediction revealed a substantial reduction (91.81% and 95.88%) in the population size of S. avenae at 60 d after treatment with miR-184 agomir, compared to the control groups. Our findings suggest that the miR-184 agomir has the potential to reduce the survival rate and mean longevity of S. avenae, highlighting its potential as a promising candidate for the development of an effective genetics-based biopesticide.

MicroRNAs (miRNA) play a vital role in insects’ growth and development and have significant potential value in pest control. Previously, we identified miR-306 from small RNA libraries within the English grain aphid, Sitobion avenae, a devasting insect pest for wheat. miR-306 not only involves in wing morphogenesis, but also is critically important for aphid survival. Its specific impacts on the life history traits, however, remain unclear. Here, we evaluate the impact of miR-306 perturbation on S. avenae populations using a two-sex life table approach. This comprehensive analysis revealed that miR-306 perturbation significantly prolongs the developmental stages (9.64% and 8.20%) and adult longevity of S. avenae, while decreasing pre-adult survival rate (41.45% and 38.74%) and slightly reducing average fecundity (5.80% and 13.05%). Overall, miR-306 perturbation negatively affects the life table parameters of the aphid population. The population prediction models show a significant decline in the aphid population 60 days post interference, compared to the control groups (98.14% and 97.76%). Our findings highlight the detrimental effects of miR-306 perturbation on S. avenae population growth and suggest potential candidate genes for the development of RNAi-based biopesticides targeted specifically at this pest species.

Climate warming exacerbates yield losses due to crop pests, but its influence on the distribution of Rhopalosiphum padi and Sitobion avenae, and consequent changes in their interspecific competition within multi-pest systems in wheat fields, remains poorly known. This study examined the impact of a 2 degrees C increase from 19 to 21 degrees C on the life table of two major aphid pests during wheat heading stage, the number of winged aphids, population dynamics in single- versus mixed- (interspecific competition) species systems, as well as their niche breadth (Bn) and niche overlap (LO) were analyzed. Results revealed that the warming increased the intrinsic rate of increase (rm) of both aphids in the lower leaves, while shortened the nymphal developmental period of both aphids. Additionally, R. padi exhibited higher rm compared to S. avenae. Warming significantly increased the abundance of both aphids but decreased the proportion of winged aphids. Moreover, Bn and LO increased when two aphids coexisted, which especially exacerbated competition in upper leaves of the wheat. The lower temperature favored the growth of S. avenae in the mix population. This advantage disappears when in the higher temperature. Consequently, warming promotes the population growth of both aphids, leading to their overlapping presence in the upper leaf of wheat and escalating interspecific competition. Under elevated temperatures, R. padi emerged as the more dominant species in mixed populations, emphasizing the significance of enhancing control measures against R. padi to guarantee high quality wheat yield in the future.

Precise, effective and green control plays an essential role in reducing environmental and ecosystem damage. Seed treatment has proven effective and long-lasting for target organisms, and exploring the reasons for long-term protection is important for sustainable agricultural development. This study examined the uptake and metabolism behaviour of thiamethoxam under seed treatment in wheat samples throughout the whole growth cycle, as well as the associated synergistic effects of thiamethoxam and its metabolites during the most severe period of aphid occurrence. Uptake and metabolism results showed that 41 % of thiamethoxam and its active metabolites (clothianidin and demethyl-clothianidin) accumulated mainly in flag leaves of wheat, severely harming aphids, which was significant in controlling leaf-feeding pests. Combined activity results showed that thiamethoxam, clothianidin and demethyl-clothianidin produced synergistic efficacy in controlling aphids, with cotoxicity coefficients ranging from 179.34 to 452.07. Compared with the control, thiamethoxam seed treatments at a rate of 1.5 a.i. g/kg seeds and 3.0 a.i. g/kg seeds can significantly enhance salicylic acid (55 % and 41 %) and jasmonic acid (168 % and 125 %) concentrations and invoke changes in the concentrations of plant secondary substances, which promoted wheat resistance to aphids. Future studies cannot ignore the synergistic effects of metabolites and plant secondary substances in pest control. These results provided data support for reducing pesticide use, increasing efficiency and making more rational use of neonicotinoid insecticides.

BACKGROUND Symbiotic bacteria affect physiology and ecology of insect hosts. The Sitobion miscanthi L type symbiont (SMLS) is a recently discovered and widely distributed secondary symbiont in the grain aphid S. miscanthi Takahashi in China. RESULTS In this study, SMLS-infected (SI) and SMLS-uninfected (SU) aphid strains were obtained from field population. The artificially SMLS-re-infected (SRI) strain was established by injecting SU aphids with the SI strain hemolymph containing SMLS. The SRI and SU strains had identical genetic backgrounds and similar microbial community structures. Compared with the SU strain, adult longevity, survival rate, and fecundity were significantly greater in the SRI strain (biological fitness of 1.48). Moreover, the SRI strain spent more time ingesting phloem than the SU strain. A comparative transcriptome analysis indicated that reproduction- and longevity-related genes were more highly expressed in the SRI strain than in the SU strain. CONCLUSION The findings indicated that the infection with SMLS enhanced the S. miscanthi fitness and feeding behavior. The beneficial effect of the SMLS on hosts could explain why it frequently infects the field populations in the grain aphid S. miscanthi Takahashi in China. This article is protected by copyright. All rights reserved.

Introduction: Carboxylesterases (CXEs) and glutathione S-transferases (GSTs) can terminate olfactory signals during chemosensation by rapid degradation of odorants in the vicinity of receptors. The tea grey geometrid, Ectropis grisescens (Lepidoptera, Geometridae), one of the most devastating insect herbivores of tea plants in China, relies heavily on plant volatiles to locate the host plants as well as the oviposition sites. However, CXEs and GSTs involved in signal termination and odorant clearance in E. grisescens remains unknown.Methods: In this study, identification and spatial expression profiles of CXEs and GSTs in this major tea pest were investigated by transcriptomics and qRT-PCR, respectively.Results: As a result, we identified 28 CXEs and 16 GSTs from female and male antennal transcriptomes. Phylogenetic analyses clustered these candidates into several clades, among which antennal CXEs, mitochondrial and cytosolic CXEs, and delta group GSTs contained genes commonly associated with odorants degradation. Spatial expression profiles showed that most CXEs (26) were expressed in antennae. In comparison, putative GSTs exhibited a diverse expression pattern across different tissues, with one GST expressed specifically in the male antennae.Disscussion: These combined results suggest that 12 CXEs (EgriCXE1, 2, 4, 6, 8, 18, 20-22, 24, 26, and 29) and 5 GSTs (EgriGST1 and EgriGST delta group) provide a major source of candidate genes for odorants degradation in E. grisescens.

Ecdysteroid hormones are key regulators of insect development and metamorphosis. Ecdysone-inducible E75, a major component of insect ecdysone signaling pathway, has been well characterized in holometabolous insects, however, barely in hemimetabolous species. In this study, a total of four full-length E75 cDNAs from the English grain aphid, Sitobion avenae, were identified, cloned, and characterized. The four SaE75 cDNAs contained 3048, 2625, 2505, and 2179 bp open reading frames (ORF), encoding 1015, 874, 856, and 835 amino acids, respectively. Temporal expression profiles showed that SaE75 expression was low in adult stages, while high in pseudo embryo and nymphal stages. SaE75 was differentially expressed between winged and wingless morphs. RNAi-mediated suppression of SaE75 led to substantial biological impacts, including mortality and molting defects. As for the pleiotropic effects on downstream ecdysone pathway genes, SaHr3 (hormone receptor like in 46) was significantly up-regulated, while Sabr-c (broad-complex core protein gene) and Saftz-f1 (transcription factor 1) were significantly down-regulated. These combined results not only shed light on the regulatory role of E75 in the ecdysone signaling pathway, but also provide a potential novel target for the long-term sustainable management of S. avenae, a devastating global grain pest.

Sulfoxaflor belongs to a new class of insecticides that is effective against many sap-feeding pests. In this study on Sitobion miscanthi (Takahashi) (i.e., the predominant wheat pest), a highly sulfoxaflor-resistant (SulR) population was obtained from a field. Its resistance to the other seven insecticides and its biological fitness were analyzed using a leaf-dip method and a two-sex life table approach, respectively. Compared with the relatively susceptible (SS) population, the SulR population was highly resistant to sulfoxaflor, with a relative insecticide resistance ratio (RR) of 199.8 and was moderately resistant to beta-cypermethrin (RR = 14.5) and bifenthrin (RR = 42.1) but exhibited low resistance to chlorpyrifos (RR = 5.7). Additionally, the SulR population had a relative fitness of 0.73, with a significantly prolonged developmental period as well as a lower survival rate and poorer reproductive performance than the SS population. In conclusion, our results suggest that S. miscanthi populations that are highly resistant to sulfoxaflor exist in the field. The possibility that insects may develop multi-resistance between sulfoxaflor and pyrethroids is a concern. Furthermore, the high sulfoxaflor resistance of S. miscanthi was accompanied by a considerable fitness cost. The study data may be useful for improving the rational use of insecticides and for exploring novel insecticide resistance mechanisms.