湖南烟区斜纹夜蛾(Spodoptera litura)的发生规律及预测方法

以郴州、宁远等县连续多年田间调查资料为基础,结合当地气象数据,分析了湖南省斜纹夜蛾的发生规律。结果表明,根据有效积温斜纹夜蛾在湖南每年发生4.0～4.5代,理论代数与实际代数相符;湖南斜纹夜蛾每年初始虫源全部为外地虫源;按虫源性质,全年可分为4个不同的发生时段;3月的诱蛾量与4—6月诱蛾量有显著的相关性,预测模型为y=233.54+112.44x4(r=0.815*,n=8);1月平均温度与4—6月诱蛾量也有明显的相关性(达90%可信度),预测模型为y1410350X3(r=0.595,n=9);同步迁飞昆虫小地老虎主迁入期(2—4月)的性诱蛾量与斜纹夜蛾主迁入期(4—6月)也具相关性,均可供发生趋势预测参考。斜纹夜蛾的百株虫量与为害率呈显著相关性。

斜纹夜蛾(Spodoptera litura)在我国的时空分布概述

概述了我国斜纹夜蛾的分布区以及在各分布区的始见虫时间。结果表明,斜纹夜蛾在我国目前的行政区划内除西藏未见报道外,其余各省、自治区、直辖市和特别行政区均有分布,主要分布于长江流域、华南和西南地区,西北地区则分布较少,在华北和东北地区分布介于二者之间;该虫可在1~2月的华南和西南地区越冬,甚至在部分地区终年可见,之后随着气温升高,向北迁飞,在长江流域、华东地区乃至华北和东北地区逐渐为害;在1~2月的华南和西南地区,该虫的寄主作物主要是槟榔芋、草莓、白莲、烟草、柑橘和蔬菜等。

Transcriptome and metabolome analysis reveal that oral secretions from Helicoverpa armigera and Spodoptera litura influence wound-induced host response in cotton

Cotton(Gossypium hirsutum)is an important fiber crop worldwide.Insect attack causes cotton yield and quality losses.However,little is known about the mechanism of cotton response to insect attack.We simulated insect feeding by applying insect oral secretions(OS)to wounds,and combined transcriptome and metabolome analysis to investigate how OS from two major pest species(Helicoverpa armigera and Spodoptera litura)affect cotton defense responses.We found that respectively 12,668 and 13,379 genes were differentially expressed in comparison with wounding alone.On addition of OS,the jasmonic acid signaling pathway was rapidly and strongly induced,whereas genes involved in salicylic acid biosynthesis were downregulated.On constructing a coexpression gene network,we identified a hub gene encoding a leucine-rich repeat receptor kinase that may play an important role in early signal recognition and transduction.OS from the two insect species altered the abundance of flavonoid-related compounds in different patterns.Gossypol remained in lower concentration after OS application than after wounding alone,suggesting a suppressive effect of OS on cotton defense response.This study illustrated transcriptional and metabolic changes of cotton in responding to OS from two chewing insect species,identified potential key response genes,and revealed evidence for OS inhibition of wounding-induced cotton defense response.

高效简便合成斜纹夜蛾Spodoptera litura F.性信息素成分(Z,E)-9,11-十四碳二烯-1-醇乙酸酯

高效简便合成高纯度斜纹叶蛾性信息素,为该虫生物防治提供技术支持。以(E)-2-戊烯-4-炔-1-醇为出发原料,制成(Z,E)构型的烯基碲试剂,然后与有机铜试剂偶联得到构型保持的(Z,E)共轭二烯,成功合成斜纹夜蛾性信息素成分(Z,E)-9,11-十四碳二烯-1-醇乙酸酯(5),纯度(对映体过量值e. e.)达到99. 5%。

Control Effects of Different Densities of Chemical Pheromones against Tobacco Cutworm Moth ( Spodoptera litura)

[ Objective ] The paper was to study the most suitable density of chemical pheromone to control Spodoptera litura in tobacco fields. [ Method ] Sixteen traps （ 4 lines x 4 rows） were placed according to the specifications of 25. 8 m ×25.8 m （ 15. 0 trap/hm2 ）, 31. 6 m× 31.6 m （ 10.0 trap/hm2 ） and 36.5 m × 36.5m （ 7.5 trap/hm2 ）. Meanwhile, a control area larger than 2 hm2 was set up with three repetitions. [ Result] Without consideration of impact of wind direc- tion, the amount of trapping moth increased with the increasing controlled area of single trap, but difference of trapping amount of moth was not significant under three different density treatments. Three placement densities could effectively control S. liture in tobacco fields, thereby reduce the use of pesticides and protect the natural enemies and reduce the control cost. [Conclusion] The suitable density of chemical pheromone traps to control S. litura was 31. 6 m x31. 6 m （10.0 trap/hm2 ）.

Occurrence and Damage Regularity of Spodoptera litura in Broccoli

[Objective] The paper was to explore the occurrence and damage regularity of Spodoptera litura in broccoli,and to reveal the annual movement regularity and seasonal fluctuation regularity of S.litura population.[Method] The monitoring data of sexual attractants at fixed points for 11 consecutive years were summarized and analyzed.[Result] The large occurrence frequency of S.litura in Taizhou was 36.4%;the annual movement showed a downward-opening parabolic form,and the movement trajectory was N =-18.416 t^(2)+182.51 t +179.71,t ={1,2,3,…,n}(n =11;r =0.691 7*).The seasonal fluctuation showed a trend of peak oscillation attenuation curve,and the total moth quantity gradually decreased from sowing to heading stage.The functional model of average daily quantity was m=0.000 2 d^(2)-0.067 5 d+6.797 3,d={1,2,3,…,n}(n =186,r=0.955 2**).Air temperature was the main external factor affecting the seasonal variation of quantity,and there was a significant correlation be-tween the number of ten-day moth trapping quantity and ten-day average temperature:M =0.243 T^(2)-6.935 1 T +46.681(n =108,r =0.560 2**)or M=2.734 4 T-35.446(n=108,r=0.500 3**).Therefore,the moth quantity in the field increased with the increase of ten-day average temperature,and the period from July to September with high temperature and less rainfall was the peak occurrence period of S.litura.[Conclusion] These models can be used to improve the prediction and early warning levels of S.litura in broccoli,and has good guiding significance for decision-making and prevention.

Prediction of Occurrence Trend of Spodoptera litura in Hunan Province in 2010——with Chenzhou Area as an Example

[Objective] The paper was to predict the occurrence trend of Spodoptera litura in Chenzhou area in 2010. [Method] With filed survey data for continuous years in Chenzhou and Ningyuan areas in Hunan Province as basic data, combining with local meteorological data, the occurrence law of S. litura in Chenzhou area in 2010 was predicted in the paper. [Result] With Chenzhou as an example, the occurrence quantity of S. litura during April and June in 2010 was only second to 2002 and 2003, which was higher than other years, indicating that 2010 would be the year with moderate and slightly heavier occurrence of S. litura. The occurrence quantity of S. litura during April and June was predicted by using temperature in January, and the correlation coefficient was significant, reaching the reliability degree of 90%. The occurrence quantity of S. litura during April and June was predicted by using sexually trapped moth during February and March, the correlation between them was very high, reaching the reliability degree of 98%. The sexually trapped moth of S. litura during April and June was predicted using sexually trapped moth by black cutworm （Agrotis ypsilon） during February and April, and the correlation coefficient between them reached the reliability degree of 90%. [Conclusion] The study provided reference for integrated control of S. litura.

斜纹夜蛾(Spodoptera litura)的胚胎发育

本文利用实验胚胎学方法详细研究了斜纹夜蛾胚胎发育的全过程。结果表明：在２４±１℃的恒温条件下，仅需８７小时即可孵化出幼虫，同时证明了马氏管起源于外胚层。

Biological activities of Solanum pseudocapsicum(Solanaceae)against cotton bollworm,Helicoverpa armigera Hübner and armyworm,Spodoptera litura Fabricius(Lepidotera:Noctuidae)

Objective:To evaluate the antifeedant,insecticidal and growth inhibition activities of Solanum pseudocapsicum(S.pseudocapsicum)seed extracts against Spodoptera litura(S.litura)and Helicotverpa armigera(H.armigera).Methods:Hcxane,diethyl cther,dichloromethanc and ethyl acetate seed extracts were prepared and tested for autifeedant,insecticidal and growth inhibitory activities against fourth instar larvae of&litura and H.armigera.Results:Ethyl acetate extract showed promising antifeedant and insecticidal activities against S.litura and H.armigera.Percentage of deformed larvae,pupae and adults were maximum in treatment of ethyl acetate extract.Percentage of successful adult emergence was deteriorated by seeds on extract treated larvae.Conclusions:Ethyl acetate extracts of S.pseudocapsicum,showed higher efficiency of antifeedant,insecticidal and growth inhibition activities.Hence,it can be used to controll agricultural insect pests,S.litura and H.armigera.

Microsatellites reveal strong genetic structure in the common cutworm, Spodoptera litura

The common cutworm, Spodoptera litura(Lepidoptera: Noctuidae), is a voracious agricultural pest. To increase understanding of the migration patterns and genetic diversity of different geographic populations of this species, we analyzed genetic variation in nine microsatellite loci among 576 individuals collected from 17 locations in China and one in Myanmar during 2011–2012. We successfully identified 162 alleles, with an average of 18 alleles per locus and a range of 5 to 34. The mean observed heterozygosity of the 18 populations ranged from 0.18 to 0.98, and the expected heterozygosity ranged from 0.19 to 0.89. For the nine microsatellite markers studied, polymorphism information content ranged from 0.18 to 0.88(mean=0.64). We found low genetic differentiation among the 18 populations(mean F-statistics(F_(ST))=0.05) and high genetic diversity among individuals. Principle coordinates analysis indicated no significant correlation between geographic and genetic distance(r=0.04). The value of N_m(N_m>4) estimated using coalescent-based methods suggests strong gene flow with migration. The nine microsatellite markers identified in this study will be beneficial for further investigation of migration patterns and genetic diversity in S. litura.

Occurrence Regularity and Sexual Pheromone Trapping Effect of Spodoptera litura in Field in Central Guizhou

The Spodoptera litura occurrence quantity in Tianlong Town,Pingba County,Anshun City was dynamically monitored by an insect sex pheromone electronic measurement and forecast system in 2015 and 2016 and the trapped effect of S. litura was studied by the home-made S. litura sex pheromone traps in Baishiyan Town,Ziyun County and Tianlong Town,Pingba County in 2016 to accurately grasp the occurrence regularity of S. litura and apply insect sex pheromone for controlling S. litura in Central Guizhou tobacco-growing region. There are 5 generations of S. litura in a year in Central Guizhou region. The first generation of S.litura occurs from late April to middle May,the second from middle-to-late July to middle-to-late August,the third from early-to-middle August to the end of September,the fourth is in the end of October and the fifth in the end of November. S. litura emigrates or enters into the overwintering stage in December. S. litura is almost in active in the daytime during the peak occurrence period of S. litura adults. The first mating time of S. litura is at 17: 30 and its peak mating time is about 22: 00. The second mating time of S. litura is at 1: 00-5: 00 and its peak mating time is about 2: 30. The trapped S. litura quantity presents an obvious layer-belt distribution that the number in the outer ring is significantly higher than that in the middle ring,and the number in the middle ring is significantly higher than that in the inner ring. The number of trapped S. litura is higher around the outer ring of the testing field and at the draught position than in the low-lying land and inner flat ground.

Ovicidal activity of Atalantia monophylla(L)Correa against Spodoptera litura Fab.(Lepidoptera:Noctuidae)

Objective:To evaluate the efficacy of Atalantia monophylla(A.monophylla)leaf in different solvent crude extracts and fractions against eggs of Spodoptera litura(S.litura).Methods:Hexane,ethyl acetate and chloroform solvent extracts of A.monophylla leaf and 12 fractions from hexane extract were screened at 5.0%t,2.5%,1.0%and 0.5%for crude extracts and 1000,500,250 and 125 mg/kg for fractions against the eggs of S.litura for the ovicidal activity.LC_(50)and LC_(90)were calculated using probit analysis.Results:Hexane crude extract showed maximum ovicidal activity of 61.94%at 5.0%concentration with a correlation value of r^2=0.81,and least LC_(50)value of3.06%.Hexane extract was fractionated using silica gel column chromatography and 12 fractions were obtained.Fraction 9 was active which showed maximum ovicidal activity of 75.61%at 1000mg/kg with the LC_(50)value of 318.65 mg/kg and LC_(90)value of 1473.31 mg/kg.In linear regression analysis,significant and high correlation(r^2=0.81%)was seen between concentration and ovicidal activity of hexane crude extracts and its active frsctien.Conclusions:As per our knowledge,this is the first report for ovicidal activity of A.monophylla against S.litura,A.monophylla could be used for the management of S.litura and other insect pests.

Effect of Trap Space Layout on Trapped Number of Spodoptera litura in Tobacco Field

[Objectives] This study was to find out the effect of trap space layout on the trapped number of Spodoptera litura in tobacco field. [Methods]From2015 to 2017,investigations were made using different hanging heights,distances( densities) and equidistant plane layout in the tobacco planting area in central Guizhou Province. [Results] The trapped number of S. litura was different at different hanging heights of the trap,and some had the difference reached the5% significant level in the trapped number. The optimum hanging height was 1. 5-2. 0 m. The trapping effect was the best at the field layout distance of20. 0-30. 0 m( density of 5-8 traps/hm^2). Under the conditions of even distribution at the equal distance between traps of 40.0 m in the field,the accumulated trapped number of S. litura from April to August was in the order of outer ring > central ring > inner ring,presenting the zonal distribution. The difference in the trapped numbers was significant among different rings,reaching the 5% significant level. [Conclusions]This study provided theoretical bases for the physiochemical control of S. litura in tobacco field.

A novel domain-duplicated SlitFAR3 gene involved in sex pheromone biosynthesis in Spodoptera litura

Fatty acyl reductases(FARs)are key enzymes that participate in sex pheromone biosynthesis by reducing fatty acids to fatty alcohols.Lepidoptera typically harbor numerous FAR gene family members.Although FAR genes are involved in the biosynthesis of sex pheromones in moths,the key FAR gene of Spodoptera litura remains unclear.In this work,we predicted 30 FAR genes from the S.litura genome and identified a domain duplication within gene SlitFAR3,which exhibited high and preferential expression in the sexually mature female pheromone glands(PGs)and a rhythmic expression pattern during the scotophase of sex pheromone production.The molecular docking of SlitFAR3,as predicted using a 3D model,revealed a co-factor NADPH binding cavity and 2 substrate binding cavities.Functional expression in yeast cells combined with comprehensive gas chromatography indicated that the SlitFAR3 gene could produce fatty alcohol products.This study is the first to focus on the special phenomenon of FAR domain duplication,which will advance our understanding of biosynthesis-related genes from the perspective of evolutionary biology.

Detoxification of insecticides, allechemicals and heavy metals by glutathione S-transferase SIGSTE1 in the gut of Spodoptera litura

Insect glutathione S-transferases （GSTs） play important roles in detoxifying toxic compounds and eliminating oxidative stress caused by these compounds. In this study, detoxification activity of the epsilon GST S1GSTE1 in Spodoptera litura was analyzed for several insecticides and heavy metals. S1GSTE1 was significantly up-regulated by chlor- pyrifos and xanthotoxin in the midgut of S. litura. The recombinant S1GSTE1 had Vmax （reaction rate of the enzyme saturated with the substrate） and Km （michaelis constant and equals to the substrate concentration at half of the maximum reaction rate of the enzyme） values of 27.95 ± 0.88μmol/min/mg and 0.87 ± 0.028 mmol/L for glutathione, respec- tively, and Vmax and Km values of 22.96 ± 0,78μmol/min/mg and 0.83 ± 0.106 mmol/L for 1-chloro-2,4-dinitrobenzene, respectively. In vitro enzyme indirect activity assay showed that the recombinant S1GSTE 1 possessed high binding activities to the insecticides chlor- pyrifos, deltamethrin, malathion, phoxim and dichloro-diphenyl-trichloroethane （DDT）. S1GSTE1 showed higher binding activity to toxic heavy metals cadmium, chromium and lead than copper and zinc that are required for insect normal growth. Western blot analysis showed that S1GSTE1 was induced in the gut of larvae fed with chlorpyrifos or cadmium. S1GSTE1 also showed high peroxidase activity. All the results together indicate that S1G- STE1 may play an important role in the gut orS. litura to protect the insect from the toxic effects of these compounds and heavy metals.

CRISPR/Cas9-mediated targeted gene mutagenesis in Spodoptera litura

Custom-designed nuclease technologies such as the clustered regularly in- terspaced short palindromic repeat （CRISPR）-associated （Cas） system provide attractive genome editing tools for insect functional genetics. The targeted gene mutagenesis me- diated by the CR1SPR/Cas9 system has been achieved in several insect orders including Diptera, Lepidoptera and Coleoptera. However, little success has been reported in agricul- tural pests due to the lack of genomic information and embryonic microinjection techniques in these insect species. Here we report that the CRISPR/Cas9 system induced efficient gene mutagenesis in an important Lepidopteran pest Spodoptera litura. We targeted the S. litura Abdominal-A （Slabd-A） gene which is an important embryonic development gene and plays a significant role in determining the identities of the abdominal segments of in- sects. Direct injection of Cas9 messenger RNA and Slabd-A-specific single guide RNA （sgRNA） into S. litura embryos successfully induced the typical abd-A deficient pheno- type, which shows anomalous segmentation and ectopic pigmentation during the larval stage. A polymerase chain reaction-based analysis revealed that the Cas9/sgRNA complex effectively induced a targeted mutagenesis in S. litura. These results demonstrate that the CRISPR/Cas9 system is a powerful tool for genome manipulation in Lepidopteran pests such as S. litura.

Molecular identification and characterization of the Orco orthologue of Spodoptera litura

A highly conserved and broadly expressed receptor protein Orco （olfactory coreceptor） is crucial for insect olfaction, and an orthologue of Orco has been identified in several insect species. Here we report the identification and characterization of Orco from Spodoptera litura. The protein displays high primary amino acid sequence conservation with other previously identified Orco orthologues. Bioinformatic analysis revealed that it has common features with other members of the Orco subfamily： seven-transmembrane domains with intracellular N-terminus and extracellular C-terminus. The transcript was detected in abundance in the chemosensory organs of the antennae of both male and female adults by real-time polymerase chain reaction analysis, and was localized at the bases of all categories of olfactory sensilla through in situ hybridization.

Expression profiles of glutathione S-transferase superfamily in Spodoptera litura tolerated to sublethal doses of chlorpyrifos

Chlorpyrifos （CPF） is a broad-spectrum organophosphate insecticide. Glu- tathione S-transferases （GSTs） in insects are a family of detoxification enzymes and they play critical roles in CPF detoxification. Spodoptera litura is one of the most destructive agricultural pests in tropical and subtropical areas in the world. In this study, 37 Slgsts from 46 unique transcripts of gsts in S. litura transcriptome data, including eight pre- viously reported GSTs, were identified and their expression patterns in susceptible and 12-generation-CPF-treated strains were analyzed to understand the roles of these Slgsts in sublethal doses of CPF tolerance. The results indicate that the members of the S. litura GST superfamily could be distinguished into three major groups： one group, includ- ing six cytosolic Slgsts （SIGSTel, SIGSTe3, SIGSTelO, SIGSTe15, SIGSTo2 and SIGSTs5） and two microsomal Slgsts （SIMGSTI-2 and SIMGST1-3）, was directly responsible for CPF induction in both 12-generation-treated and susceptible strains; the second group, including three cytosolic Slgsts （SlGSTe13, SIGSTtl and SIGSTzl） and one microsomal Slgst （SIMGSTI-1）, was induced only in the 12-generation-treated strain; the third group, including eight cytosolic Slgsts （two epsilon, three delta, one omega, one zeta and one un- classified Slgst）, was expressed 1.52-5.15-fold higher in the 12-generation-treated strain than in the susceptible strain.

Identification of a novel cytochrome P450 CYP321B1 gene from tobacco cutworm （Spodoptera litura） and RNA interference to evaluate its role in commonly used insecticides

Insect cytochrome P450 monooxygenases （CYPs or P450s） play an important role in detoxifying insecticides leading to resistance in insect populations. A polyphagous pest, Spodoptera litura, has developed resistance to a wide range of insecticides. In the present study, a novel P450 gene, CYP321B1, was cloned from S. litura. The function of CYP321B1 was assessed using RNA interference （RNAi） and monitoring resistance levels for three commonly used insecticides, including chlorpyrifos, β-cypermethrin and methomyl. The full-length complementary DNA sequence of CYP321B1 is 1814 bp long with an open reading frame of 1 488 bp encoding 495 amino acid residues. Quantitative reverse-transcriptase polymerase chain reaction analyses during larval and pupal develop- ment indicated that CYP321B1 expression was highest in the midgut of fifth-instar larvae, followed by fat body and cuticle. The expression of CYP321B1 in the midgut was up- regulated by chlorpyrifos,β-cypermethrin and methomyl with both lethal concentration at 15% （LC15） （50, 100 and 150 μg/mL, respectively） and 50%（LC50） dosages （100,200 and 300μg/mL, respectively）. Addition of piperonyl butoxide （PBO） significantly increased the toxicity ofchlorpyrifos,β-cypermethrin and methomyl to S. litura, suggesting a marked synergism of the three insecticides with PBO and P450-mediated detoxification. RNAi- mediated silencing of CYP321B1 further increased mortality by 25.6% and 38.9% when the fifth-instar larvae were exposed to chlorpyrifos and β-cypermethrin, respectively, at the LCso dose levels. The results demonstrate that CYP321B1 might play an important role in chlorpyrifos and β-cypermethrin detoxification in S. litura.