Early Warning Model of Diamondback Moth Based on ε-Support Vector Regression

The model for predicting vegetable pest diamondback moth was established based on E-Support Vector Regression algorithms in the multiply occurrence season of diamondback moth. The experimental data of diamondback moth in Guangdong vegetable were analyzed, and the result showed that when penalty factor c was 43, kernel function parameter k was O. 2, the better prediction result could be obtained by the early warning model of E-Support Vector Regression algorithms.

Transformation of Cabbage(Brassica oleracea L.var.capitata) with Bt cry1Ba3 Gene for Control of Diamondback Moth

To obtain transgenic cabbage line with broad insect resistance, a new synthetic Bacillus thuringiensis crylBa3 gene was introduced into white cabbage via Agrobacterium tumefaciens-mediated transformation and 37 transformants were obtained. Polymerase chain reaction （PCR） and Southern blot analyses confirmed that crylBa3 was successfully inserted into the genome of cabbage. Reverse transcription-polymerase chain reaction （RT-PCR） demonstrated that crylBa3 was expressed. Western blot results confirmed the production of insecticidal protein encoded by crylBa3. Insect bioassays showed that transgenic cabbages effectively controlled both susceptible and CrylAc-resistant diamondback moth （DBM） larvae.

Sub-Lethal Effects of Fenvalerate on the Development, Fecundity, and Juvenile Hormone Esterase Activity of Diamondback Moth, Plutella xylostella (L.)

The toxicities of fenvalerate （20% EC） to the 3rd instar larvae of diamondback moth （DBM）, Plutella xylostella （L.）, reared on three host plants viz., radish, oilseed rape, and cabbage were tested. The LC50 values of fenvalerate to the 3rd instar larvae of DBM varied with host plants, however, there wasn＇t any significant difference among them （P〉 0.05）. Similarly, DBM fed on three host plants had same pupal weight, pupal period, pupation rate, adult emergence rate, female ratio, and fecundity. The activity of juvenile hormone esterase （JHE, EC 3.1.1.1） in the 3rd instar larvae of DMB did not significantly vary with host plants, either. These suggested that DBM had similar fitness on the three host plant species. When fed on the host plants pretreated with fenvalerate at the concentrations equivalent to LC20, LC50 and LC50, the pupation rate, pupal weight, adult emergence rate, female ratio, fecundity, and JHE activity of the tested insects were declined as compared with insects in control treatments fed on the same host plant species. Furthermore, the pupal period of the tested insects was extended after fenvalerate treatment. The decrease in JHE activity after fenvalerate treatment in the tested insects could partly explain the changes in the mentioned growth parameters. Whether the role of fenvalerate in the inhibition of JHE activity could serve as a new way to control DBM needs further investigation.

Microbial control of diamondback moth, Plutella xylostella L. （Lepidoptera： Yponomeutidae） using bacteria （Xenorhabdus nematophila） and its metabolites from the entomopathogenic nematode Steinernema carpocapsae

Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.

Functional identification of C-type lectin in the diamondback moth,Plutella xylostella(L.)innate immunity

C-type lectins(CTLs)are a superfamily of Ca^(2+)-dependent carbohydrate-recognition proteins,and an important pattern recognition receptor(PRR)in insect innate immunity which can mediate humoral and cellular immunity in insects.In this study,we report a novel dual carbohydrate-recognition domain(CRD)CTL from Plutella xylostella which we designate PxIML.PxIML is a protein with a 969 bp open reading frame(ORF)encoding 322 amino acids,containing a signal peptide and a dual-CRD with EPN(Glu_(124)-Pro_(125)-Asn_(126))and QPD(Gln_(274)-Pro_(275)-Asp_(276))motifs.The expression of PxIML mRNA in the fat body was significantly higher than in hemocytes and midgut.The relative expression levels of PxIML in the whole insect and the fat body were significantly inhibited after infection with Bacillus thuringiensis 8010(Bt8010)at 18 h,while they were significantly upregulated after infection with Serratia marcescens IAE6 or Pichia pastoris.The recombinant PxIML(rPxIML)protein could bind to the tested pathogen-associated molecular patterns(PAMPs),and the bacteria of Enterobacter sp.IAE5,S.marcescens IAE6,Staphylococcus aureus,Escherichia coli BL21,and Bt8010 in a Ca^(2+)-dependent manner,however,it showed limited binding to the fungus,P.pastoris.The rPxIML exhibited strong activity in the presence of Ca^(2+) to agglutinate Bt8010,Enterobacter sp.IAE5 and S.aureus,but it only weakly agglutinated with E.coli BL21,and could not agglutinate with S.marcescens IAE6 or P.pastoris.Furthermore,the rPxIML could bind to hemocytes,promote the adsorption of hemocytes to beads,and enhance the phenoloxidase(PO)activity and melanization of P.xylostella.Our results suggest that PxIML plays an important role in pathogen recognition and in mediating subsequent humoral and cellular immunity of P.xylostella.

A Practical Artificial Diet for the Diamondback Moth

A new artificial diet for the diamondback moth,Plutella Xylostella(L), had been selected out successfully. The diet contained the following constituents: soybean powder, wheat germ, wheat bran powder, brewer's yeast and other constituents. So far, the diamondback; moth had been reared on this artificial diet for 25 generations and still mantained its normal biological characteristics. Under 25±1℃ and 60%￣75%RH with 12 h PH,the results of rearing the diamondback moth on the diet as follows:egg hatch,81. 3%￣94. 7 %; survival from eggsto pupae, 55. 0% ￣ 76. 7 % 1 pupal survival, 79. 7 % ￣ 100 % ; adult emergence, 80% ￣ 100 %; fecundity 94. 7￣ 144.4 eggs/ ;pupal weight, 90. 4￣110. 8 mg/20 pupae; average days to adult: , 10. 2; 13. 1. The diet is not only simpler on the constituents but also have better r-earing results and more rearing generations.

Resistance of Diamondback Moth Population against Eight Kinds of Insecticides in Luliang County of Yunnan Province

Resistance of diamondback moth （ Plutella xylostella L. ） population against eight kinds of insecticides in Luliang County of Yunnan Province in China was determined in laboratory by leaf dipping method in autumn of 2009 and spring of 2010. The monitoring results showed that diamondback moth population in Lu- liang County of Yunnan Province had produced extremely high resistance against beta-cypermethrin and avermectin; LC50 in autumn of 2009 were 1 035.21 and 1 055.19 mg/L, while those in spring of 2010 were 9.55 and 13.84 mg/L, respectively; the resistance ratios were from 291.61 to 692.00. The diamondback moth population had moderately high resistance to spinosad, indoxacarb and chlorfluazuron; LC50, in autumn of 2009 were 1.59, 2.80 and 23.97 mg/L, while those in spring of 2010 were 13.83,24.57 and 42.73 mg/L, respectively; the resistance ratios were froml3.25 to 129.98. The diamondback moth population was sensitive to diafenthiuron, BT and chlorfenapyr; LC50 in autumn of 2009 were 16.51, 47.40 and 0.85 mg/L, while those in spring of 2010 were 1.34, 3.38 and 1.60 mg/L, respectively; the resistance ratios were from 0. 77 to 8.45. The resistance of diamondback moth population in Luliang County of Yunnan Province against eight kinds of insecticides successively were diafenthiuron 〈 BT preparations 〈 chlorfenapyr 〈 spinosad 〈 indoxacarb 〈 chlorfluazuron 〈 beta-cypermethrin 〈 ave rmectin, and the resistance in spring was higher than that in autumn.

Effect of Dendranthema on Cotesia plutellae Parasitism in Brassicaceous Crops： Control of Diamondback Moth （DBM）, Plutella xylostella （Linnaeus）

The parasitism rate and the caterpillar infestation were studied by intercropping Dendranthema flowering plants with some cruciferous crops. These flowering plants increased significantly the rate of Cotesia plutellae parasitism in the adj acent plots. It reached to 42.96% in treatment plot and 18.19% in the control. Although there was no significant difference in no. of diamondback moth （DBM） larvae per plant, 29.09% in population reduction was occurred in treatment plot. Abundance of cabbage looper and armyworm were also lower in adjacent plot. But, small white butterfly population （23.46%） was higher in adjacent plots as the result of Dendranthema plant. From the present experiment, Dendranthema flowering plants should be cultivated in Brasssicaceous crops for the control of DBM by providing the essential resources to larval parasitoid C. plutellae adults and then, this plant can be used as attractive plant in the control of small white butterfly. Serious elimination （Rating 4） of candidate insecticides to adult C. plutellae was observed at their recommendation doses. Among them, less toxic effect to C. plutellae was occurred in O,O-dimethyl S-methylcarbamoylmethyl which is the highest LC50 （4,765 ppm） to DBM by leaf-disc bioassay method and the lowest LC50 （2,903 pprn） was found in marlathion. It was occurred that the test strain have resistance to the recommended dose of marlathion （1,243 ppm） and O,O-dimethyl S-methylcarbamoylmethyl （3,750 ppm）.

Laboratory Evaluation of Biorational and Low Risk Insecticides and Their Mixtures for Management of Diamondback Moth Larvae

The diamondback moth, Plutella xylostella L., has developed resistance to most insecticides used for its management. Suggested alternatives to forestall this process include biorational insecticides in mixtures with low-risk insecticides. The aim of this study was to select an insecticide or insecticide mixture that could be adopted by small-scale growers for diamondback moth management. The effectiveness of four insecticide mixtures, i.e., Agroneem Plus （neem-derived）, Spinosad （microbial origin）, thiamethoxam （neonicotinoid） and a homemade methanol Jalapefio pepper extract, in laboratory bioassays was evaluated. Binary mixtures were tested against single products at manufacturer＇s label rates. These were applied to collard greens using the leaf dip method and fed to the newly molted 2nd or 3rd instar larvae. Mixtures were evaluated for efficacy based on larval mortality and consumption of leaf discs. The results showed interactions between Jalapefio pepper extract and Spinosad and between the neem-derived Agroneem Plus and thiamethoxam at some of the tested concentrations. Mixtures with at any amount of Spinosad killed all larvae. The neem-based product gave inconsistent results in some treatments; in some case, increased leaf damage did not result in commensurate larval mortalities. The reported resistance of diamondback moth larvae to Spinosad was not observed during this study, neither with Spinosad alone nor in mixtures.

Sublethal effects of hexaflumuron on development and reproduction of the diamondback moth, Plutella xylostella （Lepidoptera： Yponomeutidae）

Effects of hexaflumuron at 10% lethal concentration （LC10） and LC25 on development and reproduction parameters of the diamondback moth, Plutella xylostella （Linnaeus, 1753） （Lep.： Yponomeutidae） were investigated. Estimated LC50, LC10 and LC25 values of leaf dip bioassay of hexaflumuron on the third instar larvae of the P xylostella were 1.48, 0.59 and 0.91 mg/L, respectively. Hexaflumuron decreased pupal weight in the parent generation at sublethal concentrations but in the offspring generation, this effect was not observed. Sublethal concentrations increased egg, first and second larval instar and pupa developmental time and shortened life span of adults, but did not change the third and fourth larval instars and pre-pupa developmental period. Also fecundity of females reduced significantly but hatchability of treatments and control were similar. Survival rate of pre-adult stages declined significantly at LC25 concentration. Reproduction parameters such as reproductive rate （R0） and intrinsic rate of increase in sublethal concentrations were significantly lower compared with control, but gross reproduction rate （GRR） at the LC10 concentration was increased and it could be hormoligosis. Also hexaflumuron significantly increased doubling time （Dt）. We conclude that the sublethal effects of hexaflumuron might exhibit significant effects on the population dynamics of P xylostella.

Low mtDNA diversity among widespread Australian diamondback moth Plutella xylostella （L,） suggests isolation and a founder effect

Populations of Australian diamondback moth （DBM） Plutella xylostella （L.）, a serious pest of cruciferous crops, display extremely low levels of genetic differentiation across Australia and New Zealand sample locations, as determined previously using microsatellite markers. These data suggest high levels of contemporary gene flow that is consistent with Australian DBM being a vagile species. Here we examine Australian DBM samples for haplotype variation using the mitochondrial DNA sequences of a 257 bp fragment of the CO1 gene. We compare this variation to equivalent mtDNA sequence variation in samples from New Zealand, Kenya and Korea. Using 42 moths collected throughout Australia we show that Australian DBM have both low mtDNA haplotype and nucleotide diversities. The three Australian haplotypes detected are closely related and they cluster with the common haplotype group from Indonesia. In addition the Australian haplotype frequency distribution resembled more that from Indonesia than that from Kenya or Korea. These data are consistent with an original strong Australian/New Zealand founder effect, from a south-eastern Asian source, with subsequent continued isolation. In a single season, the frequency of PXMt01, the most common Australian haplotype, was estimated at 15 locations spread across southern Australia and New Zealand using a polymerase chain reaction BiPASA method. The PXMt01 haplotype frequency variation was heterogenous, suggesting a small degree of population isolation that was not detected using microsatellites. Differentiation was not a function of geographical distance. These data suggest transient and sporadic local colonisation events by small numbers of founding females.

CRISPR/Cas9-based functional analysis of yellow gene in the diamondback moth,Plutella xylostella

The diamondback moth,Plutella xylostella(L.),is an economically important pest of cruciferous crops worldwide.This pest is notorious for rapid evolution of the resistance to diferent classes of insecticides,making it increasingly dificult to control.Genetics-based control approaches,through manipulation of target genes,have been reported as promising supplements or alternatives to traditional methods of pest management.Here we identified a gene of pigmentation(yellow)in P.xylostella,Pxyellow,which encodes 1674 bp complementary DNA sequence with four exons and three introns.Using the clustered regularly interspersed palindromic repeats(CRISPR)CRISPR-associated protein 9 system,we knocked out Pxyellow,targeting two sites in Exon III,to generate 272 chimeric mutants(57%of the CRISPR-treated individuals)with color-changed phenotypes of the Ist to 3rd instar larvae,pupae,and adults,indicating that Pxyellow plays an essential role in the body pigmentation of P xlostella.Fitness analysis revealed no significant difference in the oviposition of adults,the hatchability of eggs,and the weight of pupac between homozygous mutants and wildtypes,suggesting that Pxyellow is not directly involved in regulation of growth,development,or reproduction.This work advances our understanding of the genetic and insect science molecular basis for body pigmentation of P xylostella,and opens a wide avenue for development of the genctcally based pest control techniques using Pxyellow as a screening marker.

Electrophysiology and behavior feedback of diamondback moth,Plutella xylostella,to volatile secondary metabolites emitted by Chinese cabbage

The volatiles, absorbed by Porapak Q and eluted by hexane, from Chinese cabbage, Brassica campestris chinesis (L.) Makino. van communis Tsen et Lee, have been identified as allyl isothiocyanate, Z-3-hexenyl acetate, 3,7-dimethyl-l,3,6-octatriene, 2,5-hexanediol, Z-3-hexen-l-ol, nonanol, β-myrcene, α-pinene, E-2-hexen-l-ol, D-limonene, Z-3-hexenyl propanoate, linalool, geraniol, E-4-hexen-l-ol, Z-3-hexenyl isovalerate, α-terpinene, β-caryophyllene, 3-carene and α-caryophyllene, by their mass spectra and retention times in comparison with authentic samples. The first five chemicals are the main components. All components can elicite electroantennogram (EAG) responses of dia-mondback moth (DBM), Plutella xylostella, in which allyl isothiocyanate and C6 alcohols and esters, i.e. Z-3-hexen-l-ol, E-2-hexen-l-ol, E-4-hexen-l-ol, Z-3-hexenyl isovalerate and 2,5-hexanediol elicite stronger EAG responses than other components, and EAG responses of female moths to them are slightly larger than those of male

新型间二酰胺类杀虫剂的设计、合成及生物活性

为了开发出高活性、低成本的杀虫剂,以溴虫氟苯双酰胺先导化合物,通过活性亚结构拼接法合成出6个间二酰胺类化合物,并经过^(1)H NMR、^(13)C NMR和HRMS等表征手段对目标化合物Ⅰa~Ⅰf的结构进行了确认。室内杀虫、杀螨活性测试结果显示,Ⅰa~Ⅰf对小菜蛾3龄幼虫和二斑叶螨成螨均有不错的活性。对小菜蛾幼虫,Ⅰa和Ⅰe具有最好的活性,在100 mg/L时Ⅰa和Ⅰe都具有100%的杀虫活性,在50 mg/L时Ⅰa和Ⅰe的活性分别是93%,72%。对二斑叶螨成螨,Ⅰa和Ⅰd具有最好的活性,在100 mg/L时Ⅰa和Ⅰd都具有100%的活性,在50 mg/L时Ⅰa和Ⅰd的活性分别是92%,87%。

台州西兰花小菜蛾发生灾变规律与防控对策

为安全有效地控制台州西兰花小菜蛾危害,进一步降低西兰花农药残留风险,促进西兰花产业健康可持续发展,该文简要分析了西兰花小菜蛾的发生情况、灾变规律,并提出了相应的绿色防控对策。

溴虫氟苯双酰胺对小菜蛾的毒力及相关酶活性的影响

溴虫氟苯双酰胺是一种全新的双酰胺类杀虫剂,主要用于防治鳞翅目、鞘翅目、白蚁以及蚊蝇等害虫。为了明确溴虫氟苯双酰胺对小菜蛾的生物活性及解毒酶活性的影响,本研究选择氯虫苯甲酰胺为对照药剂,采用叶片药膜法测定了溴虫氟苯双酰胺对小菜蛾的生物活性,并测定了亚致死剂量(LC20、LC40)的溴虫氟苯双酰胺和氯虫苯甲酰胺对小菜蛾多功能氧化酶、谷胱甘肽S-转移酶和羧酸酯酶活性的影响。结果表明,溴虫氟苯双酰胺与氯虫苯甲酰胺对小菜蛾的生物活性相当,两者对小菜蛾的LC50分别为0.042和0.056μg/mL。与氯虫苯甲酰胺相似,亚致死剂量的溴虫氟苯双酰胺能够诱导小菜蛾体内羧酸酯酶活性升高,但溴虫氟苯双酰胺对多功能氧化酶和谷胱甘肽S-转移酶活性没有显著影响。

小菜蛾触角的显微结构及其作用

采用扫描电镜观察小菜蛾触角 ,发现雄蛾有 9种感觉器 ,雌蛾有 8种感觉器 .触角切除试验表明 ,触角是小菜蛾重要的感觉器官 。

不同地区小菜蛾对氯虫苯甲酰胺的抗药性差异

为合理使用新型杀虫剂氯虫苯甲酰胺,2011-2013年采用浸叶法,监测了广东连州、惠州、番禺、石井和广西柳州5个小菜蛾田间种群对氯虫苯甲酰胺的抗药性。监测结果表明,与敏感基线（LC50=0.23 mg/L））相比,2011年上半年,各监测点小菜蛾均处于敏感水平。2012年下半年和2013年下半年,各监测点小菜蛾均处于中、高水平抗性,抗性倍数为16~506倍。总体上小菜蛾抗药性水平下半年高于上半年。分析认为过度依赖该药,随意提高施用剂量,不合理混配等是导致小菜蛾对氯虫苯甲酰胺迅速产生抗药性的主要原因。

小菜蛾在温带地区越冬研究进展

小菜蛾是世界性重要害虫。在热带和亚热带地区冬季的十字花科植物上能正常发育繁殖,可见到各种虫态。但在温带冬季十字花科植物不能生长的地区,小菜蛾的越冬成为一个重要生态学问题。综述了亚洲、北美洲和欧洲小菜蛾越冬的研究进展。小菜蛾在日本的北海道、本州岛的北陆和东北大部分地区不能越冬,越冬北限相当于冬季积雪覆盖时间为60d的区域;在中国,小菜蛾不能在寒冷的东北地区越冬,在长江中下游以南地区冬季可见各虫态,但越冬北限尚不清楚;小菜蛾在冬天气候温和的韩国以及澳大利亚东南部继续发生;北美洲的加拿大西部和安大略地区大量的试验证明小菜蛾不能成功越冬,在美国南部小菜蛾冬季可正常发生,北部小菜蛾的越冬尚未见系统研究报道,但确认春季从南部运输的受小菜蛾感染的甘蓝等种苗是美国北部的重要虫源。小菜蛾在欧洲各地越冬的系统研究未见报道,没有证据表明在英国小菜蛾会发生有显著意义的越冬。目前小菜蛾越冬研究主要采用冬季直接试验观察和基于耐寒性试验的越冬预测两种方法。冬季直接试验观察法包括:(1)利用人工饲养的小菜蛾在田间各种潜在的越冬场所的越冬试验;(2)在秋播、野生或残留的十字花科植物上进行冬季种群的系统抽样调查;(3)越冬前后在前茬为十字花科植物的田块广泛搜寻普查小菜蛾的存活个体。基于耐寒性试验的越冬预测法:在获取小菜蛾越冬场所温度的基础上设计低温处理模式,试验低温处理后小菜蛾的存活率及后续发育和生殖。将试验数据和各地气温或小气候相结合,对小菜蛾在的越冬可能性进行推断。

牵牛子提取物对小菜蛾的生物活性

以小菜蛾为试虫,对牵牛子提取物进行了生物活性的研究。结果表明,牵牛子的甲醇提取物生物活性最高,测得对小菜蛾3龄幼虫48h的拒食中浓度(AFC50)为34.60g/L;甲醇提取物对小菜蛾具有较高的触杀作用,浸渍法的校正死亡率达100.00%,且对小菜蛾具有很强的生长发育抑制作用,24h和48h后生长发育抑制率分别为101.55%和31.16%,化蛹率仅为8.00%;其他提取物也表现出一定的生物活性。