Background: Nilaparvata lugens(the brown planthopper, BPH) andLaodelphax striatellus(the small brown planthopper, SBPH) are two of the most important pests of rice. Up to now, there was only one mitochondrial genome of rice planthopper has been sequenced and very few dependable information of mitochondria could be used for research on population genetics, phylogeographics and phylogenetic evolution of these pests. To get more valuable information from the mitochondria, we sequenced the complete mitochondrial genomes of BPH and SBPH. These two planthoppers were infected with two different functionalWolbachia(intracellular endosymbiont) strains (wLug andwStri). Since both mitochondria andWolbachiaare transmitted by cytoplasmic inheritance and it was difficult to separate them when purified theWolbachiaparticles, concomitantly sequencing the genome ofWolbachiausing next generation sequencing method, we also got nearly complete mitochondrial genome sequences of these two rice planthoppers. After gap closing, we present high quality and reliable complete mitochondrial genomes of these two planthoppers.Results: The mitogenomes ofN.lugens(BPH) andL.striatellus(SBPH) are 17, 619 bp and 16, 431 bp long with A + T contents of 76.95% and 77.17%, respectively. Both species have typical circular mitochondrial genomes that encode the complete set of 37 genes which are usually found in metazoans. However, the BPH mitogenome also possesses two additional copies of thetrnCgene. In both mitochondrial genomes, the lengths of theatp8gene were conspicuously shorter than that of all other known insect mitochondrial genomes (99 bp for BPH, 102 bp for SBPH). That two rearrangement regions (trnC-trnWandnad6-trnP-trnT) of mitochondrial genomes differing from other known insect were found in these two distantly related planthoppers revealed that the gene order of mitochondria might be conservative in Delphacidae. The large non-coding fragment (the A+T-rich region) putatively corresponding responsible for the control of replication and transcription of mitochondria contained a variable number of tandem repeats (VNTRs) block in different natural individuals of these two planthoppers. Comparison with a previously sequenced individual of SBPH revealed that the mitochondrial genetic variation within a species exists not only in the sequence and secondary structure of genes, but also in the gene order (the different location oftrnHgene).Conclusion: The mitochondrial genome arrangement pattern found in planthoppers was involved in rearrangements of both tRNA genes and protein-coding genes (PCGs). Different species from different genera of Delphacidae possessing the same mitochondrial gene rearrangement suggests that gene rearrangements of mitochondrial genome probably occurred before the differentiation of this family. After comparatively analyzing the gene order of different species of Hemiptera, we propose that except for some specific taxonomical group (e.g. the whiteflies) the gene order might have diversified in family level of this order. The VNTRs detected in the control region might provide additional genetic markers for studying population genetics, individual difference and phylogeographics of planthoppers.

Food security faces significant challenges due to the growing threat of insect pests and global climate change, making it essential to adopt sustainable agricultural strategies. Plants possess intrinsic defense systems that are activated in response to herbivore attack, including the emission of specialized volatile organic compounds (VOC) known as herbivore-induced plant volatiles (HIPVs). These volatiles aid the foraging of natural enemies (predators and parasitoids), thereby contributing to biological control of pest populations. Harnessing these chemical defense mechanisms offers a promising avenue for pest management, although natural enemy attraction does not necessarily result in pest suppression or increased crop yield. This review synthesizes plant and insect-derived chemical signaling mechanisms with direct relevance to biological control in crop agroecosystems, including field crops, orchards, vegetable systems, and protected cultivation. We emphasize recent applied research while retaining selected foundational studies that established the principal concepts and mechanisms underlying chemically mediated pest management. Considering the importance of chemical signaling in sustainable agriculture, we propose four key research directions: (1) optimizing plant defense induction mechanisms; (2) integrating HIPVs with natural enemy pheromone-based attractants; (3) combining habitat management with the provision of plant-derived food resources; and (4) harnessing plant defenses through breeding and infochemical-based genetically modified crops. Additionally, we examine the potential impacts of environmental stressors on plant–herbivore chemical communication, underscoring their importance for resilient and environmentally sustainable agricultural systems.

Overusing chemicals to manage Diaphorina citri has created insecticide resistance and negative impacts on the natural ecosystem. This has prompted the need to develop new methods of control. In the present study, we evaluated the toxicity of plant spray oil, Metarhizium anisopliae, and their combined formulations against D. citri adults through laboratory bioassays. We tested varying concentrations and application doses of the individual agents and their mixtures to determine synergistic effects. The optimal mixing ratio of M. anisopliae and plant spray oil for enhanced pest control efficacy was also identified. The results showed that the control effect of plant spray oil and M. anisopliae on D. citri became more pronounced as the concentration increased. When the two were mixed in different proportions, the synergistic effect of plant spray oil was the strongest when the mixing ratio was 5:5. Field trials demonstrated that a combined treatment of plant spray oil emulsion (9.10 g/L) and M. anisopliae (1 × 10⁸ spores/mL) achieved over 80% relative control efficacy against adult D. citri by the 6th day post-treatment. Its efficacy further increased to 96.28% by the 8th day, demonstrating its potential to replace chemical control methods. This study provides a practical example for exploring biopesticides and leveraging the synergistic effects of biogenic pesticides in preventing and controlling pests.

The Cap ‘n’ collar isoform C (CncC) transcription factor, the insect ortholog of mammalian nuclear factor erythroid 2-related factor 2 (Nrf2), serves as a central regulator of redox homeostasis and xenobiotic detoxification. Increasing evidence demonstrates that the functions of CncC extend beyond stress responses to include metamorphosis, immunity, reproduction, aging, and the development of metabolic insecticide resistance. In this review, we synthesize recent advances in insect CncC biology, with a focus on the conserved CncC/Keap1-ARE signaling pathway and its role in the detoxification of phytochemicals and insecticides. We further discuss insect-specific regulatory interactions between CncC and ecdysone signaling, as well as the gut microbiota, and compare insect CncC with mammalian Nrf2. From an applied perspective, we discuss CncC as a target for resistance management, including strategies involving RNAi and small-molecule inhibitors, its potential application in inducible bioreactors, and its value as a biomarker in environmental risk assessment. We conclude by identifying key open questions, including tissue-specific regulation, fitness costs of constitutive activation, and field relevance of CncC-mediated resistance, and highlight how addressing these gaps can support the development of sustainable pest control strategies.