Delivery of Methoprene-Tolerant dsRNA to Improve RNAi Efficiency by Modified Liposomes for Pest Control

UDP-glycosyltransferases-mediated vitellogenin protein biogenesis reveals juvenile hormone I-specific dominance in Spodoptera frugiperda reproductive programming

Juvenile hormone (JH) critically regulates reproduction in Spodoptera frugiperda (FAW) via its signaling cascade. We dissected isoform-specific roles of JH I, II, and III by using hormone injection, RNAi, and RNA-seq. Systematic modulation of JH variants revealed distinct roles in ovarian development, egg production, and vitellogenin (Vg) dynamics. Transcriptomic profiling identified JH I as the most potent inducer of reproductive pathways, specifically enriching the steroid hormone biosynthesis pathway. Within this pathway, two UDP-glycosyltransferases (UGT), SfUGT2 and SfUGT2-like, were identified as key regulators of Vg synthesis through RNAi knockdown and functional validation (qPCR, Western blot). Silencing either gene reduced Vg levels and impaired ovarian maturation. JH I exhibited the strongest induction of SfUGT2/SfUGT2-like expression, correlating with its superior reproductive activation. Notably, JH III synergistically amplified JH I/II-induced Vg accumulation and egg production, as evidenced by co-treatment assays. This cooperative interplay highlights a tiered regulatory network among JH isoforms, and provide novel insights into the endocrine regulation of reproduction in FAW, also highlight the potential for targeted manipulation of JH signaling for pest control strategies.

Engineered nanotransporters for efficient RNAi delivery in plant protection applications

RNA interference (RNAi) is increasingly used for plant protection against pathogens and pests. However, the traditional delivery method causes plant tissue damage, is affected by environmental factors, and faces difficulties in penetrating the barriers of cell walls and the limitations of plant species, ultimately leading to low delivery efficiency. With advances in nanotechnology, nanomaterials (NMs) have been identified as effective carriers for nucleic acid delivery because of their ability to operate independently of external mechanical forces, prevent degradation by bioenzymes, exhibit good biocompatibility, and offer high loading capacity. This review summarizes the application of NM-mediated RNAi against plant pathogens and pests, focusing on how different NMs break through the cell barriers of plants, pathogens, and pests according to their size, morphology, and charge characteristics. Furthermore, we discuss the advantages and improvement strategies of NMs as nucleic acid delivery carriers, alongside assessing their potential application for the management of plant pathogens and pests.

pH-responsive nanoparticles for oral delivery of RNAi for sustained protection against Spodoptera exigua

To enhance the RNAi efficiency of dsRNA against the Spodoptera exigua through a feeding method, we developed a pH-responsive nanoparticle, chitosan-polyethylene glycol-carboxyl (CS-PEG-COOH). This nanoparticle enhances RNAi efficiency by improving dsRNA stability in the midgut of S. exigua and can intelligently release dsRNA under alkaline conditions. Firstly, the CS-PEG-COOH carrier was prepared via cross-linking reactions, and the mass ratio of dsRNA to CS-PEG-COOH was obtained using electrophoretic mobility. The carrier composite materials were then characterized using isothermal titration calorimetry (ITC), transmission electron microscopy (TEM), atomic force microscopy (AFM), and Zeta potential analysis. The stability and delivery efficiency of the dsRNA/CS-PEG-COOH complex were then verified using electrophoretic mobility and fluorescence labeling methods. Finally, the RNAi efficiency and synergistic mechanism of the complex were analyzed using feeding methods and RNA-seq. The results show that CS-PEG-COOH (40.16 nm size, + 6.44 mV charge) forms a clustered complex with dsRNA through hydrogen bonding and hydrophobic interactions. CS-PEG-COOH significantly enhancing the stability and delivery efficiency of dsRNA in the midgut of S. exigua. Additionally, at pH > 8, dsRNA could be released from dsRNA/CS-PEG-COOH. The RNAi results showed that, dsRNA/CS-PEG-COOH could effectively inhibit the expression of the Acetylcholinesterase (Ace1 + Ace2) gene (65 %), and led to significantly increase mortality (51.82 %), a prolonged developmental period (25 %) and reduced egg production (22.02 %). The physiological and molecular synergistic mechanisms were revealed by RNA-seq analysis. The CS-PEG-COOH-loaded dsACE1 + dsACE2 led to down-regulation of genes related to drug metabolism, hormone synthesis, and stratum corneum biosynthesis, which inhibited insect growth and development. Overall, We developed an appropriate delivery method for dsRNA application in Lepidoptera, providing a basis for developing RNA pesticides with high efficiency and environmental safety.

Nanocarrier-mediated transdermal delivery of Lmidgf4 dsRNA expedites biological control of locusts by Beauveria bassiana

Locusts have been a major global agricultural pest that poses a serious threat to crop and livestock production. Entomopathogenic fungi (EPF) provide an eco-friendly control method; however, their efficacy usually takes slow and is unstable. To achieve an enhancement of the biocontrol efficacy of Beauveria bassiana (B. bassiana) against locusts, we developed a new strategy by which B. bassiana and nanocarrier-mediated dsRNA are co-applied across the locust cuticle. The nanocarrier star polycation (SPc) effectively delivers Lmidgf4 dsRNA (dsLmidgf4) into the locust, which targets Locusta migratoria imaginal disc growth factor 4 (Lmidgf4). SPc protects dsLmidgf4 from degradation by the hemolymph and enables efficient gene silencing. Furthermore, SPc has no adverse effects on B. bassiana spore germination and growth. Lmidgf4 interference leads to a thinner layer of endocuticle, thus facilitates infection of B. bassiana, and finally reduces the median lethal time of locusts infected with B. bassiana. In conclusion, the combination of B. bassiana and dsRNA/SPc complex overcomes the slow action of fungi, providing a novel strategy for field control of locusts.

Methionine-Based Sulfonium Lipid Mediates dsRNA for Gene Silencing in Pests

Effective gene carriers will promote the application of RNA interference (RNAi) technology in future pesticide development. This paper reports a group of novel methionine-based sulfonium lipid compounds (MSLs) and screens their gene delivery abilities in vitro and in vivo. Experiments showed that most MSLs could encapsulate nucleic acids into nanoparticles at an S/P ratio of 4:1, with nanoparticle sizes ranging from 124 to 216 nm and zeta potentials ranging from +27 to 40 mV, and could effectively protect nucleic acids from enzymatic degradation. MSLs successfully mediated the cellular uptake and transfection of nucleic acids in Kc cells and insects. Using dsRNA of CHT10 as the RNAi target, four MSLs were proven to mediate dsRNA interference in Drosophila melanogaster and Ostrinia furnacalis and achieved significant growth inhibition during larval development, eventually leading to pest death. The study demonstrates that MSLs are useful nanocarriers for the development of dsRNA pesticides.

Topical RNA Interference Induces Mortality in the Cotton-Melon Aphid Aphis gossypii with No Adverse Effect on the Predator Propylea japonica

The cotton-melon aphid (Aphis gossypii Glover), a globally distributed polyphagous pest, primarily infests cucurbit crops and leads to significant reductions in both crop yield and quality. Overreliance on chemical insecticides has resulted in widespread resistance development, highlighting the urgent requirement for alternative control strategies. This study evaluates the potential of topical RNA interference (RNAi) for managing cotton-melon aphids. We first analyzed instar-specific expression profiles of four candidate RNAi target genes (ATPE, IAP, Cat, and ilvE), employed topical dsRNA delivery to silence these genes, and subsequently evaluated their effects on aphid mortality, growth rates, and reproductive capacity. Furthermore, we investigated the non-target effects of RNAi-treated aphids on the predator ladybird beetles Propylea japonica. The results indicate that topical dsRNA delivery successfully silenced the target genes, significantly impairing aphid development and fecundity while inducing mortality, with no adverse effects on the beneficial predator. This method provides a powerful tool for insect gene functional studies and a promising solution for RNAi-based pest management.

Spray-induced gene silencing to control plant pathogenic fungi: A step-by-step guide

RNA interference (RNAi)-based control technologies are gaining popularity as potential alternatives to synthetic fungicides in the ongoing effort to manage plant pathogenic fungi. Among these methods, spray-induced gene silencing (SIGS) emerges as particularly promising due to its convenience and feasibility for development. This approach is a new technology for plant disease management, in which double-stranded RNAs (dsRNAs) targeting essential or virulence genes are applied to plants or plant products and subsequently absorbed by plant pathogens, triggering a gene silencing effect and the inhibition of the infection process. Spray-induced gene silencing has demonstrated efficacy in laboratory settings against various fungal pathogens. However, as research progressed from the laboratory to the greenhouse and field environments, novel challenges arose, such as ensuring the stability of dsRNAs and their effective delivery to fungal targets. Here, we provide a practical guide to SIGS for the control of plant pathogenic fungi. This guide outlines the essential steps and considerations needed for designing and assessing dsRNA molecules. It also addresses key challenges inherent to SIGS, including delivery and stability of dsRNA molecules, and how nanoencapsulation of dsRNAs can aid in overcoming these obstacles. Additionally, the guide underscores existing knowledge gaps that warrant further research and aims to provide assistance to researchers, especially those new to the field, encouraging the advancement of SIGS for the control of a broad range of fungal pathogens.

Development and evaluation of RNA microsphere-based RNAi approaches for managing the striped flea beetle (Phyllotreta striolata), a globally destructive pest of Cruciferae crops

BACKGROUND

RNA interference (RNAi) technology has emerged as a promising strategy for species-specific management of agricultural pests. However, the application of this technology has been significantly hindered by the instability of the interfering RNA molecules in the insect body after ingestion leading to variations in the susceptibility to the RNA triggers across different taxonomic groups of insects. Therefore, it is necessary to develop new approaches that will overcome these challenges associated with the use of RNAi-based insect pest management strategies. This study explored the use of RNA microspheres (RMS) synthesized via rolling-circle transcription (RCT) technology as a potential method for managing striped flea beetle (Phyllotreta striolata), a globally destructive pest of Cruciferae crops.

RESULTS

The synthesized RMS against the genes encoding reticulocalbin (RMS-PsRCN) and ribosomal RNA (RMS-PsrRNA) were highly effective in both silencing their target genes and causing increased P. striolata adult mortality. Relative expression levels of the target genes RMS-PsRCN and RMS-PsrRNA were decreased by 74.9% and 68.92%, respectively, in RMS fed adults, compared with the control adults fed RMS-EGFP. Consequently, the adult mortalities were 81.7% and 73.3% when fed RMS-PsRCN and RMS-PsrRNA, respectively, compared with 8.3% in the control adults. Furthermore, movements of adults fed RMS-PsRCN and RMS-PsrRNA were decreased by 70.2% and 55.7%, respectively, compared with the control adults.

CONCLUSIONS

This study shows the potential of using RMS to suppress the expression of target genes and subsequently produce significant mortality rates and behavioral changes in RMS-fed adult P. striolata. These findings underscore the promises and viability of using RMS as an effective strategy for gene function studies and species-specific management of agricultural important insect pests. © 2024 Society of Chemical Industry.

Effects of Double-Stranded RNA Degrading Nucleases on RNAi Efficiency in Beet Moth Spodoptera exigua (Lepidoptera: Noctuidae)

The insect order Lepidoptera contains many species that are considered to be agricultural pests. Specific double-stranded RNA-degrading enzymes in some moth species decrease the efficiency of RNA interference (RNAi). RNAi refers to the efficient and specific degradation of homologous mRNA induced by highly conserved, double-stranded RNA during evolution. The dsRNase enzymes can specifically recognize exogenous dsRNA, and bind to and degrade dsRNA, resulting in the inability of dsRNA to play its role. Although dsRNases play an important role in dsRNA degradation, there has been limited research on these enzymes. In this study, we successfully identified four genes related to dsRNases (named SeRNase1, SeRNase2, SeRNase3 and SeRNase4) from the genome of Spodoptera exigua. To overcome the rapid degradation of dsRNA in the midgut of S. exigua, we combined nanotechnology with biology and developed a new strategy to administer RNAi to insect pests. This binding block directed contact between the dsRNA and SeRNases to improve the efficiency of RNAi in suppressing gene expression. We demonstrate the potential of using nanotechnology to provide a novel RNAi delivery method for pest control.

Nanoscale Metal-Organic Frameworks for the Co-Delivery of Cycloxaprid and Pooled siRNAs to Enhance Control Efficacy in Diaphorina citri

RNA pesticides have emerged as a promising alternative to conventional chemical pesticides due to their high specificity and minimal environmental impact. However, the instability of RNA molecules in the environment and the challenges associated with their effective delivery to target pests limit their broader application. This study addresses these challenges by developing a dual delivery system using chitosan (CS) and Metal-Organic Frameworks (MOFs) to enhance the delivery and efficacy of double-stranded RNA (dsRNA) and cycloxaprid against Diaphorina citri, a vector of citrus greening disease. The CS-MOF nanoparticles were synthesized and characterized using scanning electron microscopy (SEM) and dynamic light scattering (DLS). Insect bioassays demonstrated that the codelivery system significantly improved insecticidal activity, achieving over 80% mortality in D. citri within 2 days. The results indicate that the encapsulation of dsRNA within MOFs enhances its stability, while the controlled release properties of the nanoparticles improve the efficacy of cycloxaprid. This novel approach shows great potential in overcoming the limitations of RNA pesticides and offers a sustainable solution for pest management in agriculture. Future research should optimize the delivery system, conduct field trials, and explore its applicability to other agricultural pests.

Hairy and Krüppel homolog 1 Comediate the Action of Juvenile Hormone/Methoprene-Tolerant Signaling Pathway in Vitellogenesis of Spodoptera frugiperda (J.E. Smith)

Spodoptera frugiperda is a major migratory invasive pest and is of global concern. Vitellogenesis, a crucial process for population multiplication in oviparous insects, is regulated by endocrine hormones. In this study, three primary responders to JH signaling, the JH receptor gene Met, and the downstream transcription factor Kr-h1 and Hairy, were first cloned and identified. RNA interference results showed that silencing SfMet significantly down-regulated the transcription levels of SfKr-h1 and SfHairy, as well as the key reproductive genes Vitellogenin (SfVg) and Vitellogenin receptor (SfVgR). Similarly, silencing SfKr-h1 and SfHairy also inhibited the transcription of SfVg and SfVgR. Silencing of SfMet, SfKr-h1, and SfHairy genes resulted in blocked ovarian development and a significant decrease in reproduction. These findings confirm that Hairy and Kr-h1 comediate the action of the JH-Met signaling pathway in vitellogenesis of S. frugiperda, providing new targets and insights for pest control.

Advances on polymeric nanocarriers for sustainable agriculture: Enhancing dsRNA/siRNA delivery to combat agricultural pests

The application of exogenous RNA for gene-silencing strategies has gained significant traction in agriculture, offering a highly efficient and eco-friendly alternative to conventional plant protection methods. This success has been driven by advances in biotechnology, from the design of long double-stranded RNA (dsRNA) and small interfering RNA (siRNA) molecules to the development of nanocarrier systems that address the challenge of RNA delivery into plant cells. In particular, polymer-based nanocarriers have emerged as a promising solution for enhancing the stability and delivery efficiency of RNA molecules. This review provides a comprehensive overview of the current state of research on the use of polymeric nanocarriers in RNA interference (RNAi) systems for crop protection. It examines key technological developments that have enabled the effective delivery of dsRNA/siRNA to target organisms, with a focus on the unique advantages polymers offer as carriers. Recent studies highlight significant progress in the preparation, characterization, and application of polymeric nanocarriers for RNA encapsulation and delivery. The review also explores the environmental and health challenges posed by these technologies, emphasizing the need for sustainable approaches in their development. Specifically, the production of nanocarriers must adhere to the principles of green chemistry, prioritizing chemical modification routes that reduce harmful residues, such as toxic solvents. Finally, this paper discusses both the current challenges and future prospects of using polymer-based nanocarriers in sustainable agriculture, offering critical insights into their potential to transform crop protection through RNAi technologies.

Liposome-based RNAi delivery in honeybee for inhibiting parasite Nosema ceranae

Nosema ceranae, a parasite that parasitizes and reproduces in the gut of honeybees, has become a serious threat to the global apiculture industry. RNA interference (RNAi) technology can be used to inhibit N. ceranae growth by targeting silencing the thioredoxin reductase (TrxR) in N. ceranae. However, suitable carriers are one of the reasons limiting the application of RNAi due to the easy degradation of dsRNA in honeybees. As a vesicle composed of a lipid bilayer, liposomes are a good carrier for nucleic acid delivery, but studies in honeybees are lacking. In this study, liposomes were used for double-stranded RNA (dsRNA) dsTrxR delivery triggering RNAi to inhibit the N. ceranae growth in honeybees. Compared to naked dsTrxR, liposome-dsTrxR reduced N. ceranae numbers in the midgut and partially restored midgut morphology without affecting bee survival and gut microbial composition. The results of this study confirmed that liposomes could effectively protect dsRNA from entering the honeybee gut and provide a reference for using RNAi technology to suppress honeybee pests and diseases.

The role of polymers in enabling RNAi-based technology for sustainable pest management

The growing global food demand, coupled with the limitations of traditional pest control methods, has driven the search for innovative and sustainable solutions in agricultural pest management. In this review, we highlight polymeric nanocarriers for their potential to deliver double-stranded RNA (dsRNA) and control pests through the gene-silencing mechanism of RNA interference (RNAi). Polymer-dsRNA systems have shown promise in protecting dsRNA, facilitating cellular uptake, and ensuring precise release. Despite these advances, challenges such as scalability, cost-efficiency, regulatory approval, and public acceptance persist, necessitating further research to overcome these obstacles and fully unlock the potential of RNAi in sustainable agriculture.

Behavioral, Physiological, and Molecular Mechanisms Underlying the Adaptation of Helicoverpa armigera to the Fruits of a Marginal Host: Walnut (Juglans regia)

In northwest China, changes in cultivation patterns and the scarcity of preferred hosts have forced Helicoverpa armigera to feed on the marginal host walnut (Juglans regia). However, the mechanisms allowing this adaptation remain poorly understood. Here, we investigated the behavioral, physiological, and molecular mechanisms underlying the local adaptation of this pest to walnut fruits. The green husk and shell generally contained higher levels of phytochemicals than the kernel. Bioassays revealed that the phytochemical-rich green husk and shell were less preferred, reduced larval fitness and growth, and elevated the activity of detoxification enzymes compared to the nutrient-rich kernel, which were further supported by a larger number of upregulated detoxification genes in insects fed green husks or shells based on transcriptome sequencing. Together, these data suggest that P450 genes (LOC110371778) may be crucial to H. armigera adaptation to the phytochemicals of walnuts. Our findings provide significant insight into the adaptation of H. armigera to walnut, an alternative host of lower quality. Meanwhile, our study provides a theoretical basis for managing resistance to H. armigera larvae in walnut trees and is instrumental in developing comprehensive integrated pest management strategies for this pest in walnut orchards and other agricultural systems.

Exogenous Application of dsRNA-Inducing Silencing of the Fusarium oxysporum Tup1 Gene and Reducing Its Virulence

Fusarium oxysporum is a widespread soil-borne fungal pathogen that can infect various plants, causing wilt and root rot diseases. The root rot disease of Atractylodes macrocephala caused by F. oxysporum is among the most serious diseases associated with continuous cropping, significantly hindering its sustainable development. In this study, we aimed to investigate the effect of exogenous application of double-stranded RNA (dsRNA) on silencing the F. oxysporum Tup1 gene to reduce its virulence and to evaluate its potential application in controlling root rot disease in A. macrocephala. The Tup1 gene was amplified from the F. oxysporum genome, and different lengths of Tup1-dsRNA were designed and synthesized. The uptake of dsRNA by the fungus was verified using Tup1-dsRNA labeled with fluorescein, and in vitro dsRNA treatment experiments were conducted to assess its impact on the growth and virulence of F. oxysporum. Additionally, Tup1-dsRNA was applied to the roots of A. macrocephala to evaluate its effectiveness in controlling root rot disease. The experimental results showed that F. oxysporum could effectively uptake exogenously applied Tup1-dsRNA, significantly reducing Tup1 gene expression. All lengths of Tup1-dsRNA inhibited fungal growth and caused morphological changes in the fungal hyphae. Further plant experiments and Reverse Transcription Quantitative Polymerase Chain Reaction (RT-qPCR) analysis indicated that Tup1-dsRNA treatment significantly reduced the incidence of root rot disease in A. macrocephala, which was supported by the reduction in peroxidase (POD) and catalase (CAT) enzyme activities, malondialdehyde (MDA) content, and proline (Pro) levels in treated root tissues. This study demonstrated that exogenous dsRNA could reduce the virulence of F. oxysporum by silencing the Tup1 gene and effectively mitigate the root rot disease it causes in A. macrocephala. The successful application of Tup1-dsRNA provided strong evidence for the potential of RNA interference (RNAi) technology in plant disease control. Future research could further optimize the design and application of dsRNA to enhance its practical value in agriculture.

Regulation of three novel pepper thiothiazolidinones on the fecundity of Spodoptera frugiperda

Spodoptera frugiperda has emerged as a major invasive pest worldwide. The utilization of chemical pesticides not only poses numerous ecological concerns but also fosters resistance in S. frugiperda. In this study, we designed and synthesized three novel thiothiazolidinone compounds (6a, 7b, and 7e) and incorporated innovative thiothiazolidinone structural elements into the piperine skeleton. Treatment with compounds 6a and 7e resulted in the blackening and agglomeration of oviduct eggs within the ovaries of certain female moths, impeding the release of normal eggs. The levels of vitellogenin and vitellogenin receptor, along with three trehalase inhibitors, exhibited a dynamic equilibrium state, leading to no discernible change in egg production but a notable increase in the generation of low-hatching-rate egg fragments. Compared with the injection of 2%DMSO, the eclosion rate of 6a injection was significantly decreased, as followed the spawning time and longevity were prolonged or significantly prolonged in the trehalase inhibitors of 6a, 7b, and 7e. We aimed to investigate the regulatory impacts of three new pepper thiothiazolidinone compounds on the reproduction of S. frugiperda, and to authenticate the efficacy of novel alginase inhibitors in inhibiting the reproduction of S. frugiperda. This research endeavors to aid in the identification of efficient and steadfast trehalase inhibitors, thereby expediting the research and development of potent biological pesticides.

Insecticidal activity and underlying molecular mechanisms of a phytochemical plumbagin against Spodoptera frugiperda

Introduction

Plumbagin is an important phytochemical and has been reported to exhibit potent larvicidal activity against several insect pests, However, the insecticidal mechanism of plumbagin against pests is still poorly understood. This study aimed to investigate the insecticidal activities of plumbagin and the underlying molecular mechanisms against a devastating agricultural pest, the fall armyworm Spodoptera frugiperda.

Methods

The effects of plumbagin on S. frugiperda larval development and the activities of two detoxification enzymes were initially examined. Next, transcriptomic changes in S. frugiperda after plumbagin treatment were investigated. Furthermore, RNA-seq results were validated by qPCR.

Results

Plumbagin exhibited a high larvicidal activity against the second and third instar larvae of S. frugiperda with 72 h LC50 of 0.573 and 2.676 mg/g, respectively. The activities of the two detoxification enzymes carboxylesterase and P450 were significantly increased after 1.5 mg/g plumbagin treatment. Furthermore, RNA-seq analysis provided a comprehensive overview of complex transcriptomic changes in S. frugiperda larvae in response to 1.5 mg/g plumbagin exposure, and revealed that plumbagin treatment led to aberrant expression of a large number of genes related to nutrient and energy metabolism, humoral immune response, insect cuticle protein, chitin-binding proteins, chitin synthesis and degradation, insect hormone, and xenobiotic detoxification. The qPCR results further validated the reproducibility and reliability of the transcriptomic data.

Discussion

Our findings provide a valuable insight into understanding the insecticidal mechanism of the phytochemical plumbagin.

Transcript Level and Sequence Matching Are Key Determinants of Off-Target Effects in RNAi

Double-stranded RNA (dsRNA) pesticides, those based on RNA interference (RNAi) technology utilizing dsRNA, have shown potential for pest control. However, the off-target effects of dsRNA pose limitations to the widespread application of RNAi and raise concerns regarding potential side effects on other beneficial organisms. The precise impact and underlying factors of these off-target effects are still not well understood. Here, we found that the transcript level and sequence matching jointly regulate off-target effects of dsRNA. The much lower expressed target genes were knocked down to a lesser extent than genes with higher expression levels, and the critical sequence identity of off-target effects is approximately 80%. Moreover, off-target effects could be triggered by a contiguous matching sequence length exceeding 15 nt as well as nearly perfectly matching sequences with one or two base mismatches exceeding 19 nt. Increasing the dosage of dsRNA leads to more severe off-target effects. However, the length of mismatched dsRNA, the choice of different RNAi targets, and the location of target sites within the same gene do not affect the severity of off-target effects. These parameters can be used to guide the design of possibly selective sequences for RNAi, optimize the specificity and efficiency of dsRNA, and facilitate practical applications of RNAi for pest control.