Search Results (170)

The use of chemical pesticides in agriculture has led to the development of resistant pest populations, posing a challenge to long-term pest management. This review aims to evaluate the scientific literature on the individual and combined use of baculoviruses with conventional chemical and biological insecticides to combat Plutella xylostella, Spodoptera exigua, and Spodoptera frugiperda in broccoli, tomato, and maize crops. Notable findings include that both individual Plutella xylostella nucleopolyhedrovirus (PxNPV) and the combination of Plutella xylostella granulovirus (PxGV) and azadirachtin at a low dose effectively control Plutella xylostella; both combinations of Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) with emamectin benzoate and chlorfenapyr reduced resistance in Spodoptera exigua and increased the efficacy of the insecticides; and the combination of Spodoptera frugiperda nucleopolyhedrovirus (SfMNPV) and spinetoram is effective against Spodoptera frugiperda. Integrating baculoviruses into pest management strategies offers a promising approach to mitigate the adverse effects of chemical pesticides, such as resistance development, health risks, and environmental damage. However, there remains a broad spectrum of research opportunities regarding the use of baculoviruses in agriculture. Full article

The growing demand for sustainable phytosanitary products has renewed interest in botanical insecticides as viable pest control tools. Amid rising demand for sustainable crop protection, this study screens Cerrado plants traditionally used in medicine to pinpoint bioactive compounds that could replace synthetic pesticides. These products have complex chemical compositions, with compounds acting synergistically through multiple mechanisms, including oral (ingestion of allelochemicals) and topical (contact of allelochemicals on epidermis) toxicity. This study evaluated the oral and topical toxicity of aqueous leaf extracts from Anemopaegma arvense (AEAa), Coussarea hydrangeifolia (AECh), Tapirira guianensis (AETg), and Duguetia furfuracea (AEDf) on Plutella xylostella. In the oral toxicity test, first-instar larvae were fed treated diets until pupation, with biological parameters monitored until adulthood. The extracts caused an average of 45% larval mortality, reduced pupal duration, and lowered egg production. In the topical toxicity test, only the extract from T. guianensis showed significant effect (p = 0.0171), causing 30% mortality in third-instar larvae. The other extracts showed no significant topical toxicity, and AECh showed no lethal or sublethal effects at all. Phytochemical screening was assessed by quantitative spectrophotometric assays, and semi-quantitative classical colorimetric tests. Major compound classes identified were tannins, flavonoids, triterpenoids, coumarins, and alkaloids. These findings highlight the potential of the evaluated plant extracts for pest control, particularly via ingestion, while also underscoring the need for further studies to better understand their efficacy and mechanisms of action. Full article

Peptidoglycan recognition proteins (PGRPs) are essential for innate immune recognition and regulation from insects to mammals. However, the specific role of PGRPs in responding to Bacillus thuringiensis (Bt) infection and maintaining midgut microbial homeostasis in Plutella xylostella remains poorly understood. In this study, we identified and characterized a PGRP gene from P. xylostella, designated PxPGRP4. The spatiotemporal expression analysis revealed that PxPGRP4 is predominantly expressed in the midgut of naïve larvae and at adult stages. A homozygous mutant strain featuring a four-base pair nucleotide deletion was successfully generated through CRISPR/Cas9-mediated knockout of PxPGRP4. The bioassay results indicated that the susceptibility of P. xylostella larvae to Cry1Ac protoxin was significantly increased by the loss of PxPGRP4 expression. Furthermore, 16S rRNA sequencing and qPCR analysis revealed that the PxPGRP4 mutants exhibited a significantly reduced total bacterial load and altered microbiota composition in the midgut compared to the wild-type strain, with a shift in the dominant bacterial family from Enterobacteriaceae to Enterococcaceae. Additionally, the knockout of PxPGRP4 resulted in significant alterations in the expression of midgut immune-related genes. These findings highlight the crucial role of PxPGRP4 as a modulator of midgut microbiota and immune responses and provide valuable insights into Bt resistance management. Full article

The co-evolution between plants and herbivorous insects has led to a continuous arms race on defense and anti-defense mechanisms. In this process, insect-derived effectors are crucial for suppressing plant defense. Despite considerable progress in plant–insect interaction studies, the functional role of heat shock cognate protein 70 (HSC70) as an effector in herbivorous insects remains poorly characterized. This study provides evidence that HSC70-3 functions as an effector in interactions between the cruciferous specialist diamondback moth (Plutella xylostella) and its host plant radish (Raphanus sativus ‘Nanpan Prefecture’). Using immunofluorescence labeling and in situ Western blot (WB), we demonstrated that HSC70-3 is secreted into plant wound sites through larval gut regurgitant during feeding. Short-term host transfer experiments revealed tissue-specific hsc70-3 expression changes, indicating a dynamic response to plant-derived challenges. These findings suggest hsc70-3 is differentially regulated at transcriptional and translational levels to facilitate insect adaptation to host plant shifts. Knockout of hsc70-3 using CRISPR/Cas9 technology significantly impaired larval growth, prolonged development duration, and reduced pupal weight on host plants, indicating its involvement in host adaptation. However, knockout mutants exhibited no significant developmental defects when reared on an artificial diet, suggesting that hsc70-3 primarily functions in modulating plant-induced defense responses rather than directly affecting insect physiology. Collectively, these findings provide evidence for the functional roles of HSC70-3 in P. xylostella and plant interactions, laying a foundation for further investigations into insect effectors and their mechanisms in modulating plant defense responses. Full article

Habrobracon hebetor is a globally acknowledged larval ectoparasitoid that is widely used to control lepidopteran pests. Wolbachia is a natural endosymbiont that regulates various aspects of the insect host biology. The ability of H. hebetor to paralyze and develop on lepidopteran larvae from five families was tested under laboratory conditions. Two lines of the wasp were used, “W+” containing a naturally occurring Wolbachia from the supergroup B, and “W−”, with the endosymbiont eradicated by antibiotic treatment, followed by propagation of 20 subsequent generations. The proportions of larvae in which host paralysis, as well as parasitoid oviposition, larval, pupal, and adult development were observed, were usually higher in W+ compared to W−. In Loxostege sticticalis, differences in these indices were not statistically significant. In Galleria mellonella, Mamestra brassicae, and Ostrinia nubilalis, some of the parasitism indices were significantly higher in W+ than in W−. In Bombyx mori and Plutella xylostella, H. hebetor could not complete its life cycle, but parasitism levels at the initial steps (from paralysis symptoms to the presence of larvae/pupae of the parasitoid) were 2–5 times lower in W− compared to W+ (p < 0.01). It can be suggested that the presence of Wolbachia is advantageous for H. hebetor, as it increases the success of parasitism in a broad range of lepidopteran hosts. Full article

Cell lines and their corresponding expression plasmids are extensively utilized in the study of insect physiology and pathology. In this research, four single-cell cultured lines (Px4-1 to Px4-4) of Plutella xylostella were established from eggs. The promoter for the P. xylostella elongation factor 1α (PxEF1α), known for its high driving activity in cells, was cloned and used to construct expression plasmids. Dual-luciferase activity assays and EGFP expression analyses demonstrated that the PxEF1α promoter exhibited the strongest driving activity in Px4-2 cells, comparable to that of the immediate-early 1 promoter associated with the homologous region 5 enhancer (AcIE1^hr5) from the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). In contrast, the driving activity of PxEF1α in cells derived from Spodoptera frugiperda, Trichoplusia ni, and Helicoverpa armigera was lower. Furthermore, the PxEF1α promoter was successfully employed to drive inward rectifier potassium 2A (Kir2A) expression in Px4-2 cells. The electrophysiological properties of the insect Kir2A channel were successfully characterized for the first time. It was observed that the PxKir2A channel possesses typical inward rectifier potassium channel properties and can be inhibited by nanomolar concentrations of VU625 and VU590. This study offers a novel approach for the expression and investigation of foreign gene function in insect cells and provides a valuable tool for the in-depth study of key biomolecules in P. xylostella. Full article

The diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae), is a serious agricultural pest that utilizes silk as a defensive mechanism, with silk fibroins playing a pivotal role in this process. Through comprehensive transcriptomic analyses, we identified 3452 differentially expressed genes (DEGs) co-expressed in the silk gland of P. xylostella and associated with silk production. The Gene Ontology (GO) analysis revealed enrichment in categories related to protein synthesis, secretion, and extracellular matrix organization, while Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis linked these genes to amino acid metabolism and protein processing pathways. Additionally, we identified three key silk fibroin genes: silk fibroin heavy chain (FibH), silk fibroin light chain (FibL), and fibrohexamerin (P25). We characterized the structure of these genes and analyzed the phylogenetic relationships, amino acid composition, hydrophilicity, and other physicochemical properties of the encoded silk fibroin proteins. The expression profiles revealed peak expression levels of these genes in the silk glands of fourth instar larvae. This integrative study enhances our understanding of the molecular mechanisms underlying silk production in P. xylostella and provides a foundation for future research into the biological roles, evolutionary trajectories, and potential applications of these silk fibroin genes in agricultural pest management and biotechnology. Full article

Avermectin is a widely used insecticide for pest control, such as the Plutella xylostella. Despite its efficacy in pest management, concerns have been raised regarding its effect on non-target species, such as the important economic insect silkworm (Bombyx mori). We aimed to investigate the effects of avermectin application on the 3D genome architecture of silkworm midgut using high-throughput techniques such as high-throughput chromosome conformation capture (Hi-C) coupled with RNA sequencing (RNA-seq) and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq). Midgut tissue samples, during the fifth instar and three days, were collected from silkworm larvae fed mulberry leaves (control group) and leaves soaked in avermectin solution for 12 h (experimental group). Our findings revealed that avermectin treatment led to significant changes, including 386 differentially expressed genes (252 up-regulated, 134 down-regulated) and increased chromatin accessibility, particularly those involved in immune response, metabolism, and cellular stress pathways. The Hi-C data revealed more intense spatial interactions in the experimental group, leading to increased expression of detoxification proteins like ABC transporter. This study provides important insights into the molecular basis of pesticide resistance and a foundational basis for further research on the genetic and epigenetic mechanisms of insect stress responses. Full article

Certain entomopathogenic fungi, such as Beauveria bassiana, are highly pathogenic to arthropod pests and are able to colonize plant tissues, thereby enhancing both plant growth and disease resistance. This study assessed three B. bassiana strains (CBM1, CBM2, and CBM3) for their pathogenicity toward insect larvae and colonization potential in wheat. The insecticidal activity of the fungi against the larvae of the major lepidopteran pests Helicoverpa armigera, Spodoptera frugiperda, Mythimna separata, and Plutella xylostella was determined. The fungi were then applied to wheat plants using seed immersion and soil drench methods; their colonization rates were compared, and the impacts of fungal colonization on wheat growth and survival were evaluated. The results demonstrated that all three strains were effective in reducing insect damage, with B. bassiana CBM1 exhibiting the highest pathogenicity followed by CBM3 and CBM2. B. bassiana CBM1 was particularly effective, with a significantly higher colonization rate achieved through soil drenching compared to seed immersion. The soil inoculation of B. bassiana resulted in increased plant height at 30 days after sowing (DAS) and root length at 15 DAS compared to the control group. B. bassiana CBM1-colonized wheat increased the mortality of fall armyworm. This research has enriched the biological control microbial resource pool and highlights the potential of B. bassiana in integrated pest management strategies. Full article

Fluxametamide, an innovative isoxazoline insecticide, acts as an antagonist of γ-aminobutyric acid-gated chloride channels. Its distinct mode of action sets it apart, lacking known cross-resistance with current insecticides. This positions fluxametamide as a promising tool for addressing insecticide resistance in Lepidoptera, thysanoptera, coleoptera, and diptera pest insects. To develop and implement successful resistance management strategies, it is crucial to establish the baseline susceptibility to this insecticide before it is registered and widely used in China. In this study, we assessed the baseline susceptibility of two widespread lepidopteran pest species, Plutella xylostella and Spodoptera exigua, to fluxametamide. The insecticide exhibited remarkably high efficacy against populations of the two lepidopteran species sampled in their primary distribution areas in China. For P. xylostella and S. exigua, the median lethal concentrations (LC₅₀) ranged between 0.040 and 0.247 mg/L, and 0.211 and 0.761 mg/L, respectively. Among populations, there was a relative low variability in susceptibility to fluxametamide, showing a 6.18-fold difference for P. xylostella and 3.61-fold for S. exigua. The suggested diagnostic concentrations for P. xylostella and S. exigua were 10 and 15 mg/L, respectively. Fluxametamide exhibited high toxicity to the selected resistant strains, which displayed strong resistance to abamectin, emamectin benzoate, and deltamethrin. No cross-resistance to fluxametamide was detected in the laboratory diamide-resistant strain. Our findings offer essential insights for crafting successful resistance management initiatives to maintain the effectiveness of fluxametamide against these significant pests. Full article

Plutella xylostella is the primary lepidopteran pest of Brassica crops due to its resistance to numerous insecticides. Multipesticide resistance in insects of agricultural importance is a global problem, and new methods of effective control that are less harmful to the environment are becoming increasingly necessary. The present study analyzed the effects of the aqueous extract of Simarouba sp. at concentrations of 10, 5, 1 and 0.1% in comparison with distilled water (as a control) on the feeding preference, oviposition, and embryonic development of P. xylostella. The results demonstrated that the aqueous extract of Simarouba sp. decreased oviposition and feeding in P. xylostella. A reduction in larval hatching was also observed, indicating ovicidal properties. In particular, the 1% concentration resulted in a more significant decrease in oviposition and the number of hatched larvae. Furthermore, concentrations of 10% and 5% caused food intake suppression, while concentrations of 1% and 0.1% reduced dietary intake by 97% and 78%, respectively. This study highlights the efficacy of Simarouba sp. aqueous extract in controlling the diamondback moth, as larval feeding and the number of individuals reaching the larval stage were reduced. Thus, the control method used in this laboratory study is expected to be successful if utilized on a large scale. Full article

The development of site-specific genome-editing tools like CRISPR (clustered regularly interspaced short palindromic repeat) and its associated protein, Cas9, is revolutionizing genetic engineering with its highly efficient mechanism, offering the potential for effective pest management. Recently, CRISPR/Cas9 gene-editing has been extensively utilized in the management of the diamondback moth, Plutella xylostella (L.), a highly destructive pest of vegetable crops, for different purposes, such as gene function analysis and genetic control. However, the progress related to this gene-editing tool in P. xylostella has not yet been summarized. This review highlights the progress and applications of CRISPR/Cas9 in uncovering the genes critical for development, reproduction, and insecticide resistance in P. xylostella. Moreover, the progress related to the CRISPR/Cas9 gene drive for population suppression and modifications has also been discussed. In addition to the significant progress made, challenges such as low germline editing efficiency and limited homology-directed repair remain obstacles to its widespread application. To address these limitations, we have discussed the different strategies that are anticipated to improve the efficiency of CRISPR/Cas9, paving the way to it becoming a pivotal tool in sustainable pest management. Therefore, the present review will help researchers in the future enhance the efficiency of the CRISPR/Cas9 system and use it to manage the diamondback moth. Full article

The diamondback moth, Plutella xylostella, is arguably the most economically impactful and widespread lepidopteran pest. Though the larval P. xylostella life stage is responsible for most of this cost through the consumption of crops, it is the adult form that spreads the pest to fresh crops all around the world, seeking them out in a seasonally expanding range. It is therefore important to understand the activity rhythms of adult P. xylostella in response to environmental cues such as light and temperature. We analysed diel rhythms in both adult clock gene expression and locomotor behaviour for the ROTH P. xylostella strain. Real-time quantitative PCR analyses of P. xylostella demonstrated diel rhythms for transcripts of the clock genes period and timeless under both entrained and free-running conditions indicating the presence of a functional daily timekeeping mechanism. However, adult locomotor rhythms exhibited temperature-driven and light-repressed regulation rather than circadian control. Thus, our analyses show a lack of coupling between the P. xylostella circadian clock and adult locomotor behaviour, which may be relevant in predicting the activity patterns of this agricultural pest. Full article

The insect NF-κB pathway is primarily constituted by nuclear factor κB (NF-κB) and the inhibitor of κB (IκB), which plays a crucial role in the innate immune response. Dorsal and Cactus, as NF-κB and IκB factors, are important downstream regulators of the Toll pathway in Plutella xylostella. In this study, the PxDorsal and PxCactus genes of P. xylostella were cloned, and the molecular docking demonstrated that PxDorsal and PxCactus can interact with each other. RT-qPCR results indicated that PxDorsal and PxCactus were expressed in all stages, and the expression of PxDorsal, PxCactus, and antimicrobial peptides PxGloverin2, PxMoricin3, and PxLysozyme2 were significantly down-regulated under Bacillus thuringiensis (Bt8010) infection. Interestingly, silencing the PxDorsal gene by RNA interference (RNAi) significantly down-regulated the expression of PxGloverin2 and PxMoricin3 and increased the epidermis melanization of P. xylostella larvae fed with Bt8010. Our findings indicate that PxDorsal and PxCactus may interact with each other, and silencing PxDorsal inhibits the expression of downstream antimicrobial peptides, thereby enhance the susceptibility of P. xylostella to Bt8010. This study contributes a theoretical basis for further research on the Toll pathway of P. xylostella to pathogens and offers insights for screening effective biological control targets from the perspective of the immune system. Full article

Emamectin benzoate (EB) is a highly effective broad-spectrum insecticide and acaricide. However, because EB is easily degraded, the conventional formulations of EB are often overapplied. In this study, polylactic acid (PLA)-based microspheres were prepared using the modified solvent evaporation method for the controlled release of EB. The microspheres were optimized to achieve higher EB loading. The effects of process parameters on the properties of microspheres, including encapsulation efficiency (EE), particle size, and pesticide loading, were investigated. Additionally, the controlled release behavior of EB microspheres was compared with that of conventional EB emulsifiable concentrate (EC). Spherical-shaped microspheres were obtained with an EE reaching 90.63 ± 1.90%, and introducing an external aqueous phase into the system can significantly enhance the EE of microspheres by over 30%. FTIR, DSC, and XRD analyses indicate that the preparation process of PLA microspheres was mainly physical encapsulation and had no chemical effect on EB. Notably, the EB microspheres displayed more potent control efficacy compared to commercial formulation EB EC against Plutella xylostella. The corrected mortality for the EB microspheres reached 90.00 ± 5.77% after 21 days of application, whereas the corrected mortality for the EB EC was only 19.23 ± 6.66% after 14 days of application. Our study demonstrates that EB-encapsulated PLA microspheres have strong potential as environmentally friendly control release EB formulations. Full article