Bt maize can provide non-chemical pest control and enhance food safety in China.

China is the world's second-largest maize producer and consumer. In recent years, the invasive fall armyworm Spodoptera frugiperda (J.E. Smith) has adversely affected maize productivity and compromised food security. To mitigate pest-inflicted food shortages, China's Government issued biosafety certificates for two genetically modified (GM) Bt maize hybrids, Bt-Cry1Ab DBN9936 and Bt-Cry1Ab/Cry2Aj Ruifeng 125, in 2019. Here, we quantitatively assess the impact of both Bt maize hybrids on pest feeding damage, crop yield and food safety throughout China's maize belt. Without a need to resort to synthetic insecticides, Bt maize could mitigate lepidopteran pest pressure by 61.9-97.3%, avoid yield loss by 16.4-21.3% (range -11.9-99.2%) and lower mycotoxin contamination by 85.5-95.5% as compared to the prevailing non-Bt hybrids. Yield loss avoidance varied considerably between experimental sites and years, as mediated by on-site infestation pressure and pest identity. For either seed mixtures or block refuge arrangements, pest pressure was kept below established thresholds at 90% Bt maize coverage in Yunnan (where S. frugiperda was the dominant species) and 70% Bt maize coverage in other sites dominated by Helicoverpa armigera (Hübner) and Ostrinia furnacalis (Guenée). Drawing on experiences from other crop/pest systems, Bt maize in se can provide area-wide pest management and thus, contribute to a progressive phase-down of chemical pesticide use. Hence, when consciously paired with agroecological and biodiversity-based measures, GM insecticidal crops can ensure food and nutrition security, contribute to the sustainable intensification of China's agriculture and reduce food systems' environmental footprint.

Systemic resistance induced in tomato plants by Beauveria bassiana-derived proteins against tomato yellow leaf curl virus and aphid Myzus persicae.

BACKGROUND: Tomato (Solanum lycopersicum L.) is an economically important vegetable crop around the globe. Tomato yellow leaf curling (TYLC) is the most devastating viral disease posing a serious threat to tomato production throughout the tropical and subtropical world. Induction of microbe-mediated systemic resistance in plants has been of great interest in recent years as a novel microbiological tool in disease and insect pest management. This in-vitro study aimed to determine the effectiveness of different strains (BB252, BB72 and ARSEF-2860) of a hypocreal fungus Beauveria bassiana against TYLCV disease and aphid Myzus persicae. Potted tomato plants exogenously treated with conidial and filtrate suspensions of B. bassiana strains and of their partially purified or purified proteins were exposed to TYLCV inoculum and aphid M. persicae. RESULTS: Results showed a significant suppression of TYLCV disease severity index by the exogenous application of conidial, filtrate and protein treatments of all B. bassiana strains and this response was directly proportional to the treatment concentration. Similarly, mean fecundity rate of M. persicae was also significantly reduced by the highest concentration of ARSEF-2860-derived elicitor protein PeBb1, followed by the highest concentrations of BB252- and BB72-derived partially purified proteins. Moreover, these B. bassiana-derived proteins also caused a significant upregulation of most of the plant immune marker genes associated with plant defense. CONCLUSION: Overall, the study findings suggest that these B. bassiana strains and their partially purified or purified elicitor proteins could be effective biological tools for the management of TYLCV and aphid infestation on tomato plants. © 2023 Society of Chemical Industry.

Transgenerational Sublethal Effects of Chlorantraniliprole and Emamectin Benzoate on the Development and Reproduction of Spodoptera frugiperda.

Spodoptera frugiperda (J. E. Smith), commonly known as the fall armyworm (FAW), causes significant damage to many different crop species. In this study, age-stage, two-sex life table analysis was used to investigate the effects of sublethal concentrations of emamectin benzoate and chlorantraniliprole on FAW development and reproduction. In the F0 generation, exposure to emamectin benzoate and chlorantraniliprole significantly impacted the duration of FAW, thus prolonging the development duration of each instar, but not the prepupal stage. Furthermore, the weight of FAW pupae was significantly reduced by emamectin benzoate at LC25 and chlorantraniliprole at LC25 in the F0 generation. With respect to fecundity, emamectin benzoate and chlorantraniliprole significantly reduced fecundity in the F0 generation. In the F1 generation, emamectin benzoate at LC10 had no significant effect on the preadult or adult stages, whereas LC25 significantly shortened the preadult period. The preadult and adult stages of FAW exposed to chlorantraniliprole at LC10 and LC25 were significantly prolonged. Furthermore, emamectin benzoate had no significant effect on the pupal weight of the F1 generation. Chlorantraniliprole had no significant effect at LC10, but significant reduced pupal weight occurred at LC25 in the F1 generation. With respect to fecundity, emamectin benzoate significantly reduced fecundity in the F1 generation. Interestingly, chlorantraniliprole significantly increased fecundity in the F1 generation, which could promote population growth and pest resurgence. These findings have important implications for the integrated pest management of FAW and provide a reference for the more effective control of FAW.

Transcriptomic analysis of Mythimna separata ovaries and identification of genes involved in reproduction.

The migratory insect Mythimna separata is a major pest of grain crops in Asia. Unfortunately, the molecular mechanisms that control and regulate reproduction in this species remain unclear. In this study, transcriptome sequencing was utilized to identify genes associated with ovary development and oogenesis. Clean sequences totaling 117.71 Gb were assembled into 178,534 unigenes with a mean length of 647.37 bp and N50 length of 837 bp. Transcriptome analysis showed that 7921 unigenes were significantly expressed in ovaries with 4403 and 3518 unigenes up- and down-regulated, respectively. Enrichment analysis with the Kyoto Encyclopedia of Genes and Genomes database suggested that 729 differentially expressed genes were significantly enriched in the top 20 pathways (q-values <0.05). Twenty genes were associated with ovary development and oogenesis and included lipases, Nanos, small heat shock proteins (sHsps) and histones; these were further verified by qRT-PCR and may play essential roles in M. separata reproduction. Collectively, our findings reveal underlying mechanisms of M.separata reproduction and may lead to RNAi-based management strategies targeting reproductive physiology.

Effects of Nano-Graphene Oxide on the Growth and Reproductive Dynamics of Spodoptera frugiperda Based on an Age-Stage, Two-Sex Life Table.

The development and reproduction of the fall armyworm (FAW), Spodoptera frugiperda, which were reared on artificial diets containing nano-graphene oxide (GO), were determined based on age-stage, two-sex life table analysis. The results showed that GO had adverse effects on FAWs. Compared with the control, the duration of the egg stage and first, second, and sixth instar larval stages increased with increasing GO concentrations; however, the lifespan of male and female adults decreased with increasing GO concentrations. Weights of FAW pupae that were supplied with GO-amended diets increased by 0.17-15.20% compared to the control. Intrinsic growth, limited growth, and net reproductive rates of FAWs feeding on GO supplemented diets were significantly lower than the control, while mean generational periods (0.5 mg/g: 38.47; 1 mg/g: 40.38; 2 mg/g: 38.42) were significantly longer than the control. The expression of genes encoding vitellogenin (Vg) and vitellogenin receptor (VgR) expression was abnormal in female FAW adults feeding on GO-amended diets; the number of eggs laid decreased relative to the control, but Vg expression increased. In conclusion, GO prolonged the developmental period of FAWs, decreased fecundity, and led to a decline in the population size. The study provides a basis for the rational use of GO as a pesticide synergist for FAW control.

Windborne migration amplifies insect-mediated pollination services.

Worldwide, hoverflies (Syrphidae: Diptera) provide crucial ecosystem services such as pollination and biological pest control. Although many hoverfly species exhibit migratory behavior, the spatiotemporal facets of these movement dynamics, and their ecosystem services implications are poorly understood. In this study, we use long-term (16-year) trapping records, trajectory analysis, and intrinsic (i.e., isotope, genetic, pollen) markers to describe migration patterns of the hoverfly Episyrphus balteatus in northern China. Our work reveals how E. balteatus migrate northward during spring-summer and exhibits return (long-range) migration during autumn. The extensive genetic mixing and high genetic diversity of E. balteatus populations underscore its adaptive capacity to environmental disturbances, for example, climate change. Pollen markers and molecular gut analysis further illuminate how E. balteatus visits min. 1012 flowering plant species (39 orders) over space and time. By thus delineating E. balteatus transregional movements and pollination networks, we advance our understanding of its migration ecology and facilitate the design of targeted strategies to conserve and enhance its ecosystem services.

Orius similis (Hemiptera: Anthocoridae): A Promising Candidate Predator of Spodoptera frugiperda (Lepidoptera: Noctuidae).

The bug Orius similis Zheng is a native generalist predator of insect pests in southern China. The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), is a notorious defoliator that is now an economically important insect pest throughout China. To investigate the ability of O. similis to control FAW, we evaluated the predatory capacity, behavior, and functional response of O. similis with respect to FAW and their olfactory response. Both females and males successfully preyed on FAW eggs and first-instar larvae but not on second-instar or older larvae. Adult O. similis only attacked and killed one egg or one larva at a time before sucking the prey, and similar predatory behavior was also observed with regard to FAW egg masses. Both female and male O. similis exhibited type II functional response when preying on FAW eggs and first-instar larvae. Maximum estimated prey consumed per day was 23.7 eggs and 26.2 larvae for adult females and 22.5 eggs and 19.6 larvae for adult males. Moreover, in a Y-tube olfactometer experiment, both female and male O. similis exhibited a significant preference for maize (Zea mays L.) seedlings damaged by FAW over clean air, healthy seedlings, FAW feces, and FAW, suggesting that seedlings damaged by FAW may releases specific volatiles attracting the predator. Collectively, the results of the study suggest that O. similis is a promising candidate for the biological control of FAW eggs and first-instar larvae, particularly given its attraction to FAW-damaged leaves, which may enable it to locate the target prey rapidly.

Mitochondrial genome and phylogenetic analysis of Psylliodes punctifrons Baly (Coleoptera: Chrysomelidae: Galerucinae).

We sequenced and annotated mitochondrial genome (mitogenome) of oilseed rape pest Psylliodes punctifrons Baly for the first time. The mitogenome is 15,611 bp, and the nucleotide composition of 37 genes is highly A + T biased (A: 34.2, C: 11.6, G: 12.1, and T:42.1). All PCGs start with ATN and stop with TAR, except COX3 and ND4 that stop with incomplete codon T-. The phylogenetic tree confirms that P. punctifrons is clustered with other Psylliodes species. This study enriches the mitogenomes of agricultural pests.

The complete mitochondrial genome sequence of Acisoma panorpoides Rambur, 1842 (Odonate: Libellulidae).

The phylogenetic relationships of dragonflies have received great attention all the time. For a better understanding the phylogenies among odonate insects, the paper presented the complete mitochondrial genome of Acisoma panorpoides based on next generation sequencing data of total genomic DNA. The total length comprised 15,249 bp and the 37 genes (2 rRNA genes, 13 protein coding genes and 22 tRNA genes). Gene content and gene arrangement were identical to other odonate mitogenomes. Phylogenetic analyses using the whole sequences of the mitochondrial genome placed A. panorpoides as a sister species to Hydrobasileus croceus in Libellulidae.

Seasonal Migration Pattern of Nilaparvata lugens (Hemiptera: Delphacidae) Over the Bohai Sea in Northern China.

The brown planthopper Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) is a major, regionally migratory pest of rice crops in Asia. Despite intensive studies, the seasonal pattern of migration in this species remains largely unknown, especially in northern China. Analysis of monitoring data of light trapping at Beihuang island in northern China showed that brown planthopper migrants could be found at the island in any month from July to October. However, the daily number of brown planthopper migrants varied considerably from day to day, month to month, and year to year. Most of migrants were caught from July to September, with fewer in October. Simulation of backward trajectories showed that there was temporal variation in the source areas of brown planthopper migrants trapped at Beihuang. A majority of migrants trapped at Beihuang in July came from south of Beihuang. In contrast, migrants caught in August and September could be from any direction around the island. Results suggested that the brown planthopper migrants likely traveled northward in July, and Multidirectionally in August and September in northern China. Some of brown planthopper in northeastern China could escape the 'Pied Piper effect' and migrate southward in September.

Seasonal Migration of Pantala flavescens Across the Bohai Strait in Northern China.

Pantala flavescens (Fabricius 1798) (Odonata: Libellulidae) is one of the most common species of migratory dragonflies. P. flavescens adults were captured by a searchlight trap on Beihuang Island (BH Island; 38°24'N, 120°55'E) from 2003 to 2016, where there is no freshwater. This inspired our research to analyze the pattern of seasonal migration and population dynamics. Stable hydrogen isotope measurement and the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) were used to simulate the migration pathway of P. flavescens between different breeding habitats. The results showed that there was no significant difference among population numbers of this overseas migration across years (F13, 2161 = 0.85, P = 0.604); however, the numbers were significantly different across months (F5, 2161 = 3.91, P = 0.003). Our geospatial natal assignment model suggested that P. flavescens trapped on BH were originated in different geographical regions and might have three movement strategies: wandering around northern China and north-bound (positive) and south-bound (negative) movements. Among them, the majority were engaged in wandering around northern China. Model simulations suggested that P. flavescens toured around BH. The results contribute to the knowledge of P. flavescens population ecology in a large-scale geographic region and will aid in the prediction and interpretation of insect migration patterns in response to climate change.

Effects of temperature on mate location in the planthopper, Nilaparvata lugens (Homoptera: Delphacidae).

The planthopper, Nilaparvata lugens Stål (Homoptera: Delphacidae), uses acoustic signals generated by abdominal vibration and transmitted through rice (Oryza sativa L.) plants to locate mates. The influence of temperature (20, 28, and 32°C) on abdominal vibration patterns of individual females and males, proportion of mated females, and responsivity of male to female vibrational signals was investigated. When female and male adults were observed individually, temperatures of 20 and 32°C inhibited abdominal vibration by both genders in terms of proportion of vibrating insects, time spent in vibration per insect, time spent per bout of vibration, or all of these; the effects were more pronounced at 32°C than at 20°C especially in males at 32°C. Although not significantly different, male responsivity to vibrating female was relatively high at 28°C, lower at 32°C, and still lower at 20°C, and finally more males located females at 28°C than at 20°C, which contributes to the higher proportion of mated females at 28°C than at 20 or 32°C. Our results indicate that temperatures of 20 and 32°C inhibit the production of abdominal vibration and, to some extent, reduce male responsivity to female vibrational signals, which may partially explain the frequent population outbreaks in N. lugens in the years with warm autumn.