Tea-oil tree (Camellia oleifera Abel) is an important woody oil tree in southern China, cultivated on more than 7,400 ha in Shexian County, Anhui Province. In a survey conducted from 2016 to 2017 i...

Bacillus thuringiensis is an effective entomopathogen, and its crystal toxin expressed in transgenic crops has been widely used for pest control. However, insect resistance risk is the main threat to the continued successful utility of Bt crops. Several studies reported the role of midgut microbiota in Bt resistance, but the mechanism remains controversial. In the present study, using high-throughput sequencing of the bacterial 16S ribosomal RNA gene, we surveyed the midgut bacterial flora of Ostrinia furnacalis from one Bt-susceptible (ACB-BtS) and two Bt-resistant (ACB-AbR and ACB-FR) strains and explored the mortality of O. furnacalis after eliminating the gut bacteria. Gut bacterial diversity in Bt-resistant strains was significantly lower in Bt-resistant than in Bt-susceptible strains. Ordination analyses and statistical tests showed that the bacterial community of ACB-AbR was distinguishable from ACB-BtS. The genus Halomonas was dominated in ACB-BtS, but the unclassified_Enterobacteriaceae was the most enriched genus in ACB-AbR and ACB-FR. Furthermore, interactions of the bacterial community are more complex in Bt-resistant strains than in Bt-susceptible strains. Moreover, the mortalities of ACB-AbR and ACB-BtS strains treated by the Cry1Ab toxin were significantly reduced after eliminating the gut bacteria. Our findings suggest that Bt stressors structured in the midgut bacterial community and the microbiota have the potential to regulate the Bt-induced killing mechanism.

Spodoptera frugiperda is a globally significant migratory agricultural pest that requires proactive monitoring. Understanding the molecular mechanisms underlying the interactions between pathogenic microorganisms and S. frugiperda is crucial for enhancing the effectiveness of microbial control agents against this pest. This study used transcriptome sequencing and molecular biology techniques on S. frugiperda larvae infected by bacteria and fungi to investigate the composition and molecular regulatory mechanisms of its immune system. A total of 598 immune-related genes were identified. Upon microbial infection, most immune-related genes showed an upregulated expression trend. Phylogenetic analysis revealed that the immune gene repertoire of S. frugiperda is relatively conserved. The expression of the genes of peptidoglycan recognition proteins in different tissues of S. frugiperda induced by microorganisms at different times was verified using qPCR, and the results confirmed that these genes were significantly upregulated under specific pathogenic infections. This study elucidates the immune transcriptome of S. frugiperda in response to various pathogenic microorganisms, providing valuable insights for improving the effectiveness of existing microbial agents and developing new, highly efficient, and specific biopesticides.

Asian corn borer (ACB), Ostrinia furnacalis, is a predominant pest species that is widely distributed across major corn-growing regions in China. Tetraniliprole, a novel diamid insecticide, exhibited good efficacy on lepidopteran insect pests and was officially sanctioned for controlling ACB in China. In this study, a tetraniliprole-resistant strain called ACB-TLR was obtained from a susceptible strain, ACB-SS, after 10 continuous generation selections with tetraniliprole. Additionally, the fitness cost of the ACB-TLR strain was assessed. The results showed that ACB developed 11.58-fold resistance to tetraniliprole and the realized heritability was estimated as 0.213. The ACB-TLR strain displayed 2.10 times cross-resistance to chlorantraniliprole, but we found no cross-resistance to emamectin benzoate and deltamethrin. The development time of larvae and pupae was significantly prolonged, the adult longevity was significantly shorter, and the pupation and emergence rates were significantly reduced in the ACB-TLR strain than in the ACB-SS strain, with a relative fitness of 0.39. The current study indicated that ACB has the potential to develop resistance to tetraniliprole in the field. However, the decreased fitness may allow insecticide resistance to be managed.

The fall armyworm (FAW), Spodoptera frugiperda, is a notorious pest on maize. The push-pull strategy based on intercropping and interplanting system has been reported to effectively reduce the damage of FAW. However, the suitable mode for FAW management has not been reported thoroughly. We therefore investigated the adaptability, feeding preference and oviposition of FAW on maize (Zea mays L.), mung bean (Vigna radiata L.), soybean (Glycine max L.), common bean (Phaseolus vulgaris L.), red bean (Vigna angularis Willd.) and yardlong bean (Vigna unguiculata L.), which commonly used in maize-legume intercropping system. We also evaluated the occurrence of FAW in push-pull cropping test. Results showed that FAW could complete life history reared on the six hosts, and it was more suitable for maize, red bean and yardlong bean but less suitable for the others. The feeding preference and oviposition tests revealed that FAW had strong preference for maize and yardlong bean, while the opposite was true for mung bean. In addition, the push-pull cropping test showed that the injured rate on maize intercropping mung bean surrounded by yardlong bean was significantly less than that on maize monocropping and maize surrounded by yardlong bean. The study indicated that mung bean and yardlong bean are promising introduced into push-pull control, and could provide a new perspective for FAW management in maize-legume intercropping system.

This study explores the molecular mechanisms underlying diapause in the parasitoid wasp Telenomus remus (Nixon) (Hymenoptera: Platygastridae), a critical egg parasitoid for the biological control of the invasive pest Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). While effective in pest management, T. remus faces limitations in large-scale applications due to its short lifespan and low viability under storage conditions. Diapause, a state of developmental arrest, was successfully induced in T. remus using photoperiod manipulation (0L:24D), allowing for extended survival and improved storage potential. Transcriptome sequencing identified 2642 differentially expressed genes, with 617 involved in 284 enriched pathways, including calcium signaling and phototransduction. The study found that the expression levels of CBP1 and CBP2, genes encoding calcium-binding proteins, were significantly downregulated during diapause. As key regulators in calcium ion-mediated signal transduction pathways, the downregulation of CBP1 and CBP2 may lead to the suppression of intracellular calcium signaling, thereby affecting light signal transduction and energy metabolism regulation. This suggests that during diapause, insects may reduce calcium signaling activity to suppress physiological functions, maintain a low metabolic state, and decrease sensitivity to environmental stimuli. Additionally, ARR genes still exhibited differential expression, further supporting their potential role in phototransduction and diapause regulation.