Supplemental light is often used in fruit production, but few studies have been conducted on pitaya. In this study, supplemental blue light was applied to pitaya for four hours each night in the field from flowering to fruit ripening to examine changes in peel and pulp physicochemical parameters and metabolites. Blue light treatment significantly increased fruit weight, improved fruit firmness by increasing pectin content and retarding hemicellulose degradation, and enhanced antioxidant enzyme activity. Blue light had minor effects on primary metabolites but more pronounced effects on volatiles. By affecting alanine, aspartate and glutamate metabolism, blue light treatment resulted in significant fruit growth, increased accumulation of bioactive ingredients in the peel, and significantly altered the accumulation of flavor-associated volatile compounds, such as organic acids, esters and terpenes in the pulp. Our results provide an important reference for improving the yield and quality of pitaya production using supplemental light in the field.

Poplar (Populus spp.) has a short growth cycle and considerable economic value. Also, it is highly susceptible to various diseases. Of these, the canker disease has a significant impact on the health and productivity of poplar plants. This study aimed to explore the resistance mechanism of poplar against Cytospora spp. by transcriptomics and metabolomics sequencing analyses that were performed after 0, 48, and 96 h of inoculation in resistant and susceptible varieties of poplar. Both transcriptome and metabolome profiles demonstrated a robust activation of defense mechanisms in the resistant variety upon pathogen challenge. Of all differentially expressed genes (DEGs), 175 DEGs were selected and combined with 65 candidate differentially accumulated metabolites (DAMs) following the same trend for further conjoint analysis. The combined analysis results revealed a significant correlation between 8 DAMs and 72 DEGs. Sixteen DEGs associated with each DAM were screened to verify their expression levels using quantitative reverse transcription-polymerase chain reaction. Most of the eight DAMs belong to the category of terpenoids. It suggested that terpenoids were crucial components of a poplar's defense response to canker disease. This study provides a genetic basis and novel insights for future investigations of poplar resistance mechanisms against Cytospora spp.

IntroductionThis study presents the essential oils (EOs) derived from Origanum majorana L. (Marjoram), Mentha spicata L. (Spearmint) and Ocimum basilicum L. (Basil), which are explored for their insecticidal potential against Spodoptera littoralis larvae.MethodsEOs were extracted and analyzed using gas chromatography-mass spectrometry (GC-MS), identifying 47, 37 and 27 compounds in O. majorana, M. spicata and O. basilicum, respectively.ResultsMajor constituents include terpinen-4-ol (25.47 %) and sabinene (18.3%) in O. majorana, piperitenone oxide (43.83 %) in M. spicata, and methyl (E)-cinnamate (48.69 %) in O. basilicum. Toxicity assays demonstrated significant larvicidal activity with LC50 values of 1.18 % for O. majorana, 0.43% for M. spicata, and 0.51% for O. basilicum. Furthermore, these EOs notably influenced the expression of defense-related genes in S. littoralis, with treated larvae showing an ~80% increase in PR1, endoglucanase (PR2) and chitinase gene expression compared to controls. Differential display confirmed the amplification of these regulated genes in treated insects.DiscussionThis research underscores the efficacy of EOs from O. majorana, M. spicata and O. basilicum as natural insecticides, providing valuable insights for sustainable pest management through specific gene markers.

Background: Cavariella salicicola (Hemiptera: Aphidinae) is a pest on Salix spp. and various Umbelliferae (Apiaceae) vegetables. However, the taxonomic status and phylogenetic relationship of the genus Cavariella within Aphidinae remain controversial due to the small body size and easily confused external morphology. Methods: The complete mitochondrial genome of C. salicicola collected from Oenanthe javanica was sequenced using the Illumina platform and compared with C. theobaldi. The codon usage bias of two Cavariella aphids was assessed through Enc plot, PR2 plot, and neutrality plot analyses. Furthermore, phylogenetic trees were constructed based on both Maximum Likelihood and Bayesian Inference analysis. Results: The C. salicicola mitochondrial genome comprises 15,720 bp and represents a typical circular DNA molecule with a high AT content of 83.8%. It contains the standard 37 genes, including 2 ribosomal RNAs (rRNAs), 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), and 2 long non-coding regions (control and repeat regions). Varying degrees of codon usage bias were found across different PCGs, and the bias was predominantly influenced by natural selection rather than mutational pressure. The ratio of nonsynonymous to synonymous substitutions (Ka/Ks) indicated that all PCGs in C. salicicola, as well as most other Aphidinae species, are under strong purifying selection. The phylogenetic analysis based on Maximum Likelihood and Bayesian Inference both strongly supported the monophyly of Aphidinae, Macrosiphini, and Aphidini. Crucially, the monophyletic genus Cavariella was resolved as a sister group to all other sampled species within the tribe Macrosiphini. Conclusions: This study provides new molecular data to support the sister relationship of the genus Cavariella to other Macrosiphini aphids. This study will enhance our understanding of phylogenetic relationships within the subfamily Aphidinae.

Using transgenic insect-resistant maize C0030.3.5 and control strain DBN318 as materials, the ground trap method was used to systematically investigate the selection data of different habitats of ground arthropods in the above spring and summer maize fields for two consecutive years from 2016 to 2017. The species richness (S), diversity index (H'), dominance concentration index (D) and species evenness index (J) of surface migrating arthropods were calculated. The effects of transgenic maize C0030.3.5 on habitat selection of field surface arthropods were evaluated by cluster analysis and factor analysis. The results showed that planting transgenic insect-resistant maize C0030.3.5 had no significant effect on habitat selection of ground arthropods. The results provided some data support for environmental safety assessment of GM crops.

The cotton aphid, Aphis gossypii, belonging to Hemiptera Aphididae is a worldwide pest on various plants. This pest is particularly notorious for its high tolerance to both temperature and insecticides. Heat shock proteins (HSPs), which have been recognized as molecular chaperones, play pivotal roles in the response of insects to environmental stress. However, information on HSP genes in A. gossypii and their expression response remain limited. In this study, 50 HSP genes were identified in the A. gossypii genome, including 3 HSP90s, 15 HSP70s, 11 HSP60s, 19 HSP40s and 2 sHSPs. Phylogenetic analysis strongly supported the family classification of A. gossypii HSP genes. All of the AgHSPs were distributed across four chromosomes, and several gene duplication events were observed. Transcriptome data revealed that most AgHSPs could be induced by short-term high temperature treatment. Conversely, most HSPs decreased their transcription levels under long-term high temperature exposure. Notably, three HSPs (AgHSP40-9-X2, AgHSP40-15 and AgHSP70-8) were consistently up-regulated after insecticide exposure in both susceptible and resistant populations. Moreover, the expressions of HSPs across several morphs of aphids were systematically evaluated for the first time. Our findings provide fundamental data for future studies and enhance our understanding of the roles of HSPs in environmental stress adaptation in A. gossypii.

IntroductionThe beet armyworm Spodoptera exigua (Hübner, 1808)(Lepidoptera: Noctuidae) represents a cosmopolitan polyphagous lepidopteran pest of paramount agricultural significance, necessitating strategic intervention during the reproductive-competent imaginal stage to mitigate population amplification and geographic dissemination. Chlorantraniliprole is an anthranilic diamide insecticide with high selectivity for arthropod ryanodine receptors (RyR).MethodsThis investigation systematically evaluated median lethal (LC₅₀) ramifications of chlorantraniliprole upon adult S. exigua demographic performance and transgenerational fitness consequences utilizing three distinct administration modalities: oral consumption via chlorantraniliprole-fortified sucrose solution, pronotal microdroplet deposition, and pedal contact exposure.ResultsPronounced inter-treatment variability was documented across multiple life-history parameters. Oral ingestion of the toxic nutrient matrix dramatically curtailed adult longevity by 6.067 days and median lethally diminished reproductive output by 309.3 eggs, while concurrently suppressing parental egg viability by 52.01% relative to untreated controls. Pronotal topical application demonstrated negligible effects on parental demographic metrics but significantly compromised F₁ egg hatchability by 42.93%. Tarsal contact exposure exerted the most profound transgenerational perturbations, prolonging F₁ larval developmental duration by 2.969 days, augmenting pupal biomass by 0.008 g, and extending pupal metamorphic chronometry by 17.6 hours. Additionally, this treatment modality reduced F₁ egg viability by 42.83%, decreased F₁ fecundity by 411.9 eggs, suppressed imaginal emergence rates by 30.8%, and elevated developmental malformation incidence by 5.28%.DiscussionThese findings demonstrate that delivery methodology fundamentally modulates chlorantraniliprole's demographic impact trajectory, with oral administration optimizing parental suppression while pedal contact maximizing transgenerational attenuation of S. exigua population dynamics. Future research should explore developing chlorantraniliprole-laced food attractants and advancing pest control timing to enhance efficacy.

The cotton-melon aphid (Aphis gossypii) is a globally distributed species with highly differentiated populations and various life cycle types. Based on the haplotype classification of the A. gossypii, this study aimed to quantify the effects of latitude, host specialization on transformation of the sexual morph of the A. gossypii. Additionally, symbiotic bacteria potentially involved in the formation of sexual morph were investigated. The results showed that I):The most frequent haplotypes on the 29 host plants were Hap1 (60.42%), Hap17 (13.29%), and Hap4 (7.55%). Haplotypes in cotton fields of 10 geographic populations were predominantly Hap1 and Hap4. II):A. gossypii from the Northwestern inland, the Yellow River basin, and the Yangtze River basin cotton regions all were induced sexual morphs, except for Hap1 from low latitudes. There are also differences in the efficiency of sex aphid induction between haplotypes under the same region/latitude(Jiangsu Yangzhou), which can be corresponded to three life cycle types: holocyclic (Hap1 and Hap4), facultative (Hap17 and Hap1-1), and specialized parthenogenetic (Hap3 and Hap16) life cycle. Interestingly, sexual morphogenesis of A. gossypii with facultative life cycle are more susceptible influenced by the host. Subsequent field surveys in Yangzhou, Jiangsu have also confirmed that the haplotypes capable of sexual morphology transformation under natural rhythm variations are Hap1 and Hap4. It is worth mentioning that these sexual aphids are mainly distributed on some Malvaceae plants, Chinese prickly ash, and pomegranate. However, aphids with specialized parthenogenetic life cycle can complete their entire life history by overwintering on crops or weeds (such as capsella and veronica) in greenhouses or outdoors. III):The relative abundance of Arsenophonus, Pantoea and Enterobacter varied among haplotypes. In particular. the relative abundance of Arsenophonus was generally higher in holocyclic aphids than in anholocyclic aphids in the parthenogenetic morphology. Additionally, Arsenophonus higher in gynoparas and females than in males in the sexual morphology. It can be observed that the aforementioned symbiotic bacteria may play a role in the development of the specialized or reproductive mode of the A. gossypii. The present study contributes to our understanding of the ecological adaptations of the A. gossypii to different climatic conditions and host plants. Moreover, it will furnish a crucial foundation for unravelling the diversification of reproductive modes exhibited by A. gossypii.

Vegetable fields are often contaminated by heavy metals, and Spodoptera exigua is a major vegetable pest which is stressed by heavy metals mainly by feeding. In this study, cadmium accumulation in the tissues of S. exigua exposed to cadmium and its effects on the growth and development of the parents and the offspring were investigated. Under the stress of different concentrations of cadmium(0.2, 3.2, and 51.2 mg kg -1 ), the cadmium content in each tissue of S. exigua increased in a dose-dependent manner. At the larval stage, the highest cadmium accumulation was found in midgut in all three cadmium treatments, but at the adult stage, the highest cadmium content was found in fat body.In addition, the cadmium content in ovaries was much higher than in testes. When F 1 S. exigua was stressed by cadmium and the F 2 generation was not fed a cadmium-containing diet, the larval survival, pupation rate, emergence rate and fecundity of the F 2 generation were significantly reduced in the 51.2 mg kg -1 treatment compared to the corresponding F 1 generation. Even in the F 2 generation of the 3.2 mg kg -1 treatment, the fecundity was significantly lower than in the parental generation. The fecundity of the only-female stressed treatment was significantly lower than that of the only-male stressed treatment at the 3.2 and 51.2 mg kg -1 cadmium exposure levels. When only mothers were stressed at the larval stage, the fecundity of the F 2 generation was significantly lower than that of the F 1 generation in the 51.2 mg kg -1 treatment, and it was also significantly lower than in the 3.2 and 0.2 mg kg -1 treatments.The results of our study can provide useful information for forecasting the population increase trends under different heavy metal stress conditions and for the reliable environmental risk assessment of heavy metal pollution.

The cotton-melon aphid Aphis gossypii Glover is a severe pest worldwide. Interhaplotype genomic variation can be used as a starting point to analyze the adaptability of Ap. gossypii. In this study, we utilized long-read PacBio HiFi sequencing and HiC scaffolding techniques to assemble a near telomere-to-telomere gap-free genome assembly of Hap4. The assembly had two gaps totaling 321.24 Mb. We characterized five telomeric repetitive regions (GGTTA)n, including the four found at the 3’ end of the chromosomes, and obtained new structural information about the telomeres. Due to the improved sequencing technology, we also identified more than 55.03 Mb of repetitive DNA in the genome assembly of Hap4, which contributed significantly to the increase in genome size compared to that of Hap1 and Hap3. Most of the additional repetitive DNA content was located on the X chromosome, and the tandem repeat sequence occupied 16.8% of the X chromosome length. The Hap4 assembly showed that the X chromosome exhibited a greater abundance of AT-rich satDNA arrays (11 satDNA arrays longer than 100 kb) than that observed in the autosomes (A1 and A2 harboured 3 and 1 satDNA arrays). We detected presence-absence variations, insertions, and deletions events between Hap1, Hap3, and Hap4 Ap. gossypii, which had significant effects on gene expression. Additionally, we identified a male-specific glyceraldehyde-3-phosphate dehydrogenase of fungal origin in all strains of Ap. gossypii. This comprehensive genome assembly provides valuable insights into the structural characteristics of highly repetitive regions and allows comparative genomic analyses that facilitate our understanding of Ap. gossypii’s adaptation and diversification.

Diaphania indica (Lepidoptera: Crambidae) is one of the most important pests infesting many cucurbitaceous vegetables. During the rearing of insect eggs, we observed a fungal infection in these insect eggs which causes the death of pests. Therefore, this work aimed to isolate and identify this fungus by amplifying the internal transcribed spacer (ITS) region of the rDNA, as well as evaluating the efficiency of this fungus in control. Aspergillus flavus, ‘PP125556’, showcased robust pathogenicity against a range of D. indica pests. The results showed that colonies of ‘PP125556’ cultivated on potato dextrose agar (PDA) exhibited distinctive morphological characteristics, transitioning from pristine white to verdant green. Bioassays demonstrated concentration-dependent mortality rates of D. indica larvae and adults when exposed to varying concentrations of ‘PP125556’ conidia, with the highest concentration (1 × 109 conidia/mL) inducing significant death, with the highest mortality (53.06% for eggs, 70.57% for larvae, and 86.65% for adults). Furthermore, examination under a stereomicroscope revealed conspicuous external symptoms in infected larvae, including reduced mobility, darkened body pigmentation, and the emergence of white hyphae, indicative of mortality. Additionally, infected eggs exhibited inhibited hatching and the emergence of green hyphae, while infected adults displayed mortality and white hyphae colonization, underscoring the potent biocontrol efficacy of A. flavus ‘PP125556’ against D. indica across diverse developmental stages.

[目的]研究重金属镉胁迫对昆虫生长发育的影响,为重金属镉胁迫评价提供依据.[方法]采用镉含量分别为0、0.2、3.2 和51.2 mg/kg的人工饲料饲喂甜菜夜蛾初孵幼虫直至化蛹,测定不同虫态(3 龄幼虫、5龄幼虫、雌/雄成虫)甜菜夜蛾体内保幼激素和蜕皮激素的滴度.[结果]低浓度镉(0.2 mg/kg)胁迫下甜菜夜蛾幼虫体内保幼激素和蜕皮激素滴度升高;随着镉浓度的升高,保幼激素和蜕皮激素的滴度逐渐下降.镉胁迫下甜菜夜蛾成虫体内保幼激素滴度升高,蜕皮激素滴度降低;随着镉浓度的升高,保幼激素(JH)和蜕皮激素(MH)的滴度无明显变化.[结论]JH和MH是昆虫生长发育和繁殖的重要调控因子,重金属镉胁迫通过改变昆虫体内JH和MH的滴度进而对昆虫生长发育和生殖产生影响.

Spodoptera exigua（Hübner） is a polyphagous pest that causes serious damage to crops, vegetables and flowers. In this paper, we investigated the effects of different host plants on the growth, development and reproduction of S. exigua after feeding on different host plants, and the host selection behavior of S. exigua adults for oviposition and larval feeding on different host plants, using celery Apium graveolens, amaranth Amaranthus retroflexus, split onion Allium fistulosum L. var. caespitosum Makino and bok choy Brassica chinensis as subjects. The results showed that S. exigua larvae developmental epochs, pupae weight, egg number and other parameters differed significantly among host plants. S. exigua larvae that fed on split onion had the longest developmental duration and those that fed on Amaranthus had the shortest developmental duration. The heaviest pupae and the highest egg number were found in those feeding on bok choy, while the lowest egg number was found in those feeding on celery and the lightest pupae were found in those feeding on split onion. It was found that the S. exigua were able to reproduce on all four host plants, among which, amaranth and bok choy were more favorable host plants than celery and split onion. The order of egg number on the four host plants was: amaranth（222.1 eggs/♀）, split onion（181.6 eggs/♀）, celery（96.3eggs/♀）, bok choy（26.2 eggs/♀）. In the larval host selection test, the S. exigua had the highest feeding selection rate on bok choy and the lowest on split onion; and the 3rd instar larvae were the most selective and the 5th instar larvae were relatively less selective. The results showed that the egg-laying selection of adults and larval feeding selection were not consistent, while the larval feeding selection was consistent with their growth and development trends, which provides scientific support for the use of push-pull strategy to prevent and control S. exigua.

In order to further explore the control mechanism of celery Apium graveolens on the whitefly Bemisia tabaci, the effects of intercropping with celery on the development and survival of whiteflies on pepper plants and the whitefly-resistant metabolites in pepper leaves were investigated. The results showed that intercropping with celery affected the developmental duration and the survival rate of whiteflies on pepper plants. With increasing density of celery, the nymph survival rate and the developmental duration increased. When the ratios of pepper∶celery were 2∶1, 2∶2, and 2∶3, the developmental duration from egg to pseudopupa on pepper plants was significantly increased by 5.47%, 9.76%,16.64%, and the whitefly survival rate was decreased by 20.85%, 16.65%, 54.15%, respectively. Intercropping with celery also had effects on the metabolites unfavorable to whiteflies. After ten days of intercropping, the proline content was decreased by 20.23%, 19.72% and 29.98%; the soluble sugar content was increased by 23.92%, 30.20% and 37.25%; the flavonoid content was increased by 15.70%,24.92% and 27.08%, and the total phenol content was increased by 36.80%, 30.40% and 8.80%, respectively, compared with the control. These results indicate that celery intercropping could alter the content of metabolites in pepper leaves, which might affect whitefly development.

草地贪夜蛾[Spodopterafrugiperda(J.E.Smith)]是近年传入我国的一种重要的农业害虫.以转三价抗虫耐除草剂转化体"双抗12-5"(含Cry1Ab+Cry2Aj+epsps)和转双价抗虫耐除草剂转化体"C0030.3.5"(含Cry1Ab+epsps)及其对照品种(系)"宏硕899"和"C0010.1.1"为材料,按随机区组设计小区,每小区200 m2,分别调查各小区玉米植株上草地贪夜蛾幼虫数量与虫龄、玉米叶片被害情况、玉米抽雄率、吐丝率等,并对各小区进行测产.结果表明:草地贪夜蛾对玉米的破坏性非常大,在玉米成株期至抽雄吐丝期为害后,常规对照品种玉米产量损失分别达62.98％("宏硕899")、65.42％("C0010.1.1");即使是带有抗虫材料的转基因玉米,产量损失也达到53.34％("双抗12-5")和13.31％("C0030.3.5");受草地贪夜蛾的为害,2个对照品种玉米的吐丝率低于60％.根据草地贪夜蛾对玉米叶片的为害、虫口密度及玉米产量损失等,提出草地贪夜蛾轻发生、中等偏轻、至特大发生为害的六级标准,为生产上草地贪夜蛾的快速精准测报和有效防控提供理论依据.

Aphis gossypii Glover (Hemiptera, Aphidoidae) is a polyphagous pest, whose complex phenotypic form, combined with its high fecundity and short reproductive cycle, has caused serious economic losses to agriculture worldwide. Photoperiod plays an important role in the reproduction of aphids. However, the molecular mechanisms underlying its response to seasonal photoperiodic changes are not known. In this study, the effects of different photoperiod treatments (8 L:16 D, 10 L:14 D, 12 L:12 D and 14 L:10 D) on A. gossypii reproduction in the first, third, and fifth generations at low temperatures were investigated. Then, transcriptome sequencing analysis was performed after the fifth generation of A. gossypii, exposed to different photoperiods (8 L:16 D and 12 L:12 D), using high-throughput sequencing technology. The results showed that (I) the effect of photoperiod on aphids was gradually evident with increasing exposure generations. In general, daylight extension help the A. gossypii to reproduce with the optimum photoperiod of L:D 12:12. (II) The transcriptome analysis results showed that 170 differentially expressed genes (DEGs) (123 downregulated and 47 upregulated genes) were identified between aphids under 8 h daylight and 12 h daylight. (III) Gene Ontology (GO) enrichment analysis showed that the DEGs involved in "proteolysis", "metabolic process", "peptidase activity" and "structural molecule activity" were significantly enriched; Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that there were more DEGs in "Longevity regulating pathway-multiple species", "Lysosome", "Endocytosis", "Spliceosome" and "Protein processing in endoplasmic reticulum". (IV) Ten related genes were chosen for validation of statistical analysis based on RNA-Seq by the reverse transcription quantitative (RT-qPCR). The comparison was consistent with the expression pattern and supported the accuracy and reliability of RNA-Seq. In summary, the genes involved in these pathways play an important role in the reproduction of A. gossypii under photoperiodical changes. These will contribute to the sustainable management of cotton aphids through the disruption of their reproduction by the method of RNA interference in the future.

Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is a worldwide pest that damages over 900 host plant species. The volatile organic compounds (volatiles) of contrasting plants, as well as their growth stage, influence this pest's infestation behavior. The chemical contents of volatiles isolated from three plants (Gossypium hirsutum, Abutilon theophrasti, and Ricinus communis) during various growth phases (pre-flowering, fluorescence, and fruiting) were examined, as well as their influence on the behavior of adult B. tabaci. The olfactometer studies demonstrated that growth periods of the three plants affected the preference of B. tabaci. Volatiles of piemarker and cotton plants had dissimilar levels of attraction to adults during all stages. Volatile substances released by the castor at the stage of flowering had repellent effect on B. tabaci. In the plant versus plant combination, piemarker volatiles before and during anthesis were most preferred by adults, followed by cotton and then castor. A total of 24, 24, and 20 compounds were detected from volatiles of piemarker, cotton, and castor, respectively, and proportions among the compounds changed during different stages of plant development. The olfactory responses of B. tabaci to volatile compounds presented that linalool and high concentration of (Z)-3-hexenyl acetate had a strong trapping effect on this pest, while nonanal had a significant repellent effect at high concentration. This study indicates that distinct plants and their growth stage affect their attractiveness or repellency to B.tabaci adults, which are mediated by changing plant volatiles. These compounds obtained by analysis screening can be adopted as potential attractants or repellents to control Mediterranean (MED) B. tabaci.

以转基因抗虫玉米C0030.3.5和对照品系DBN318为材料,2016～2017连续两年采用直接观察法、地面陷阱法、黄板诱虫法对春、夏玉米田的节肢动物进行调查,对相关参数进行差异显著性检验,比较两类玉米田节肢动物群落之间的差异.结果表明,2016年春、夏玉米田转基因抗虫玉米C0030.3.5 3种调查法的田间节肢动物群落丰富度S、Simpson优势集中性指数D、Shannon-Wiener多样性指数H'、均匀性指数J等群落多样性参数与对照品系DBN318相比无显著差异.2017年的结果与2016年基本一致,相关性达0.98.从种植季节分析,不管哪个季节的转基因抗虫品种C0030.3.5,3种调查法的S、D、H'、J与对照品系DBN318相比,不同品种间群落多样性参数均无显著差异.结果表明,转基因抗虫玉米C0030.3.5对田间节肢动物群落多样性无显著影响.

With the wide-scale adoption of transgenic Bacillus thuringiensis (Bt) cotton, Apolygus lucorum (Meyer-Dür) has become the most serious pest and has caused extensive yield loss in cotton production. However, little is known about the defense responses of cotton at the seedling stage to A. lucorum feeding. In this study, to elucidate the cotton defense mechanism, cotton leaves were damaged by A. lucorum for 0, 4, 12 and 24 h. The transcriptomic results showed that A. lucorum feeding elicits a rapid and strong defense response in gene expression during the whole infestation process in cotton plants. Further analysis revealed that at each assessment time, more differentially expressed genes were up-regulated than down-regulated. The integrated analysis of transcriptomic and metabolic data showed that most of the genes involved in jasmonic acid (JA) biosynthesis were initially up-regulated, and this trend continued during an infestation. Meanwhile, the content levels of JA and its intermediate products were also significantly increased throughout the whole infestation process. The similar trend was displayed in condensed tannins biosynthesis. This research proved that, after plants are damaged by A. lucorum, the JA pathway mediates the defense mechanisms in cotton plants by promoting the accumulation of condensed tannins as a defense mechanism against A. lucorum. These results will help us to discover unknown defensive genes and improve the integrated pest management of A. lucorum.

Uroleucon formosanum is an important aphid pest of lettuce, but basic information on its biology is scarce. In this study, effects of three constant temperatures (17, 21, and 25 °C, simulating the mean temperature range in greenhouses) on the development and fecundity of U. formosanum were analyzed by constructing a life table. U. formosanum could develop and reproduce under all three temperatures, but the survival rate, development, and fecundity of U. formosanum were affected by temperature. The intrinsic rate of increase was lowest at 17 °C (0.17) and it was significantly less than at 21 °C (0.20) and 25 °C (0.23). Furthermore, U. formosanum had the lowest finite rate of increase (1.19) and the largest mean generation time (20.21) at 17 °C. These results mean that U. formosanum is less adapted to the lower temperatures (17 °C) among these three set temperatures. To screen insecticides for control, susceptibility of U. formosanum to six insecticides including chlorpyrifos, abamectin, beta-cypermethrin, imidacloprid, nitenpyram, and thiamethoxam was evaluated. U. formosanum was relatively sensitive to all six test insecticides. Chlorpyrifos had the highest toxicity to U. formosanum (LC50 = 3.08 mg/L). These data may help to develop integrated management strategies for better population control of U. formosanum.