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Sample records for budworm helicoverpa assulta

  1. Chemosensory receptor genes in the Oriental tobacco budworm Helicoverpa assulta.

    Science.gov (United States)

    Xu, W; Papanicolaou, A; Liu, N-Y; Dong, S-L; Anderson, A

    2015-04-01

    The Oriental tobacco budworm (Helicoverpa assulta) is a specialist herbivore moth and its larvae feed on Solanaceous plants. (Z)-9-hexadecenal (Z9-16: Ald) is the major sex pheromone component in H. assulta but the specific pheromone receptor (PR) against Z9-16: Ald has not yet been identified. In the present study, we integrated transcriptomic, bioinformatic and functional characterization approaches to investigate the chemosensory receptor genes of H. assulta. We identified seven potential PRs with 44 olfactory receptors, 18 gustatory receptors and 24 ionotropic receptors, which were further studied by in silico gene expression profile, phylogenetic analysis, reverse transcription PCR and calcium imaging assays. The candidate PR, HassOR13, showed a strong response to the minor sex pheromone component, (Z)-11-hexadecenal, but not the major component, Z9-16: Ald, in calcium imaging assays. This study provides the molecular basis for comparative studies of chemosensory receptors between H. assulta and other Helicoverpa species and will advance our understanding of the evolution and function of Lepidoptera insect chemosensation. PMID:25430896

  2. Comparative study on the responses of maxillary sensilla styloconica of cotton bollworm Helicoverpa armigera and Oriental tobacco budworm H. assulta larvae to phytochemicals

    Institute of Scientific and Technical Information of China (English)

    汤德良; 王琛柱; 罗林儿; 钦俊德

    2000-01-01

    Using the electro-physiological technique, the sensory mechanisms of maxillary sensilla styloconica to stimulants and deterrents were explored on two closely related species, the generalist Helicoverpa armigera and the specialist H. assulta. The results showed that: (i) in both species, cells sensitive to sucrose and azadirachtin were mainly in the lateral sensillum styloconicum, and those to inositol were in the medial sensillum styloconicum; (ii) sensitivity of medial sensillum styloconicum in H. assulta to inositol was higher than that in H. armigera; (iii) among 6 tested deterrents, only azadirachtin evoked high impulse discharge from the lateral sensillum styloconicum in both insects; (iv) the deterrents could disturb stimulants evoking impulse discharge from maxillary sensilla styloconica of both species in different degrees: To sucrose evoking impulses on lateral sensillum styloconicum, for H. armigera capsaicin had a strong inhibition and gossypol had a weak inhibition, while for H. assulta tann

  3. Biology and life table studies of the oriental tobacco budworm, Helicoverpa assulta (Lepidoptera: Noctuidae),influenced by different larval diets

    Institute of Scientific and Technical Information of China (English)

    Kai-Yun Wang; Yong Zhang; Hong-Yan Wang; Xiao-Ming Xia; Tong-Xian Liu

    2008-01-01

    Development, survivorship, pupal weight, oviposition, and life table parameters laboratory on an artificial diet, pepper (Capsicumfrutescens L.), and tobacco (Nicotiana tobacum L.). We found that the average developmental time of immature stages was longest on tobacco (36.2 d), intermediate on pepper (34.4 d), and shortest on artificial diet (33.5 d).Immature survival from egg to pupa varied from 31% on tobacco, 43% on pepper, and 74% on artificial diet. Pupal weight ranged from 197.4 mg/pupa on tobacco, 233.1 mg/pupa on pepper and 253.4 mg/pupa on artificial diet. The average numbers of eggs laid by adults reared as larvae on the artificial diet, pepper, or tobacco were 614, 421 and 334 eggs/female,respectively. Numbers of remaining eggs in ovaries of the adult females reared as larvae on the artificial diet, pepper, or tobacco were 16, 26, and 42 eggs/female, respectively. The longevity of adult females developed from larvae reared on the three diets was not significantly different, whereas the longevity of male adults from the larvae reared on artificial diet was longer (16.8 d) than that for males reared on tobacco (13.8 d) and pepper (13.3 d). The intrinsic, finite, gross, and net rates of increase were highest for females reared as larvae on artificial diet, lowest for females emerging from larvae reared on tobacco, and intermediate for females emerging from larvae reared on pepper. Generation times and doubling time of H. assulta were shortest for larvae fed artificial diet, intermediate from larvae reared on pepper, and longest from larvae reared on tobacco. We concluded that the artificial diet was the most suitable larval diet ofH. assulta followed by pepper, and tobacco.

  4. Comparative study on the responses of maxillary sensilla styloconica of cotton bollworm Helicoverpa armigera and Oriental tobacco budworm H. assulta larvae to phytochemicals

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Using the electro-physiological technique, the sensory mechanisms of maxillary sensilla styloconica to stimulants and deterrents were explored on two closely related species, the generalist Helicoverpa armigera and the specialist H. assulta. The results showed that: (i) in both species, cells sensitive to sucrose and azadirachtin were mainly in the lateral sensillum styloconicum, and those to inositol were in the medial sensillum styloconicum; (ii) sensitivity of medial sensillum styloconicum in H. assulta to inositol was higher than that in H. armigera; (iii) among 6 tested deterrents, only azadirachtin evoked high impulse discharge from the lateral sensillum styloconicum in both insects; (iv) the deterrents could disturb stimulants evoking impulse discharge from maxillary sensilla styloconica of both species in different degrees: To sucrose evoking impulses on lateral sensillum styloconicum, for H. armigera capsaicin had a strong inhibition and gossypol had a weak inhibition, while for H. assulta tannic acid, gossypol, and tomatine all had strong inhibition except nicotine and capsaicin; to inositol evoking impulses on medial sensilum styloconicum, for H. armigera inhibition of tomatine was strong but that of gossypol was weak; and for H. assulta inhibition of gossypol was strong but that of nicotine was weak.

  5. A simple and reliable method for discriminating between Helicoverpa armigera and Helicoverpa assulta (Lepidoptera: Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    Jia Chen; Yu-Chun Wu; Xin Chen; Ya-Jie Ji; De-Xinh Zhang

    2011-01-01

    The cotton bollworm Helicoverpa armigera and the oriental tobacco budworm H.assulta are sibling species,both being important agricultural pests.Morphologically,the two insects are almost indistinguishable at the egg,larval and pupal stages.One of the big challenges in the study of these insects,in particular in integrated pest management,is a timely and dependable identification of these insects at their early stages of development.Here,we report a H.armigera-specific nuclear DNA marker,and demonstrate that it can be employed to reliably discriminate between H.armigera and H.assulta by simple polymerase chain reaction amplification experiment.

  6. Hybridization between Helicoverpa armigera and Helicoverpa assulta (Lepidoptera: Noctuidae): development and morphological characterization of F1 hybrids

    NARCIS (Netherlands)

    Zhao, X.C.; Dong, J.F.; Tang, Q.B.; Yan, Q.B.; Celbic, I.; Loon, van J.J.A.; Wang, C.Z.

    2005-01-01

    Reciprocal hybridizations between Helicoverpa armigera (Hubner) and Helicoverpa assulta (Guenee) were studied. The cross between females of H. armigera and males of H. assulta yielded only fertile males and sterile individuals lacking an aedeagus, valva or ostium bursae. A total of 492 larvae of the

  7. Inheritance of electrophysiological responses to leaf saps of host- and nonhost plants in two helicoverpa species and their hybrids

    NARCIS (Netherlands)

    Tang, Q.B.; Huang, L.Q.; Wang, C.Z.; Tang, Q.B.T.; Zhan, H.; Loon, van J.J.A.

    2014-01-01

    The polyphagous cotton bollworm Helicoverpa armigera (Hubner) and the oligophagous oriental tobacco budworm Helicoverpa assulta (Guenee) (Lepidoptera: Noctuidae) display contrasting heritable feeding preferences for cotton and pepper leaves. In this study, electrophysiological response patterns to c

  8. Host selection of Helicoverpa armigera and H.assulta and its inheritance

    Institute of Scientific and Technical Information of China (English)

    WANG Chenzhu; DONG Junfeng; TANG Deliang; ZHANG Jihong; LI Wei; QIN Junde

    2004-01-01

    The difference in host selection between the polyphagous Helicoverpa armigera (Hübner) and the oligophagous H. assulta Quenée was examined, with cotton (Gossypium hirsutum), tomato (Lycopersicon esculentum) (hosts of H. armigera), tobacco (Nicotiana tobaccum) (host of both H. armigera and H. assulta), and bush redpepper (Capsicum frutescens) (host of H. assulta) as testing plants. A multiple-choice test was used with caged plant cuttings for adult oviposition and with leaf discs for larval feeding. A no-choice test was run for evaluating larval growth rate. The results indicated that the relationship between larval performance and adult preference of H. assulta was more conspicuous than that of H. armigera. Reciprocal hybridization between H. armigera and H. assulta followed by backcrossing of the hybrids (F1) with H. armigera was also carried out for genetic study on host selection of these two insect species. A two-choice test with cotton and bush redpepper leaf discs showed that H. armigera larvae preferred to feed on cotton, and H. assulta larvae to bush redpepper; feeding preferences of the two F1 lines were intermediate between those of their parents, but close to that of their female parent; preference indexes of backcross lines also showed that both maternal factor and chromosomal inheritance were involved in feeding selection of two Helicoverpa species.

  9. Characterization of the Helicoverpa assulta nucleopolyhedrovirus genome and sequence analysis of the polyhedrin gene region

    Indian Academy of Sciences (India)

    Soo-Dong Woo; Jae Young Choi; Yeon Ho Je; Byung Rae Jin

    2006-09-01

    A local strain of Helicoverpa assulta nucleopolyhedrovirus (HasNPV) was isolated from infected H. assulta larvae in Korea. Restriction endonuclease fragment analysis, using 4 restriction enzymes, estimated that the total genome size of HasNPV is about 138 kb. A degenerate polymerase chain reaction (PCR) primer set for the polyhedrin gene successfully amplified the partial polyhedrin gene of HasNPV. The sequencing results showed that the about 430 bp PCR product was a fragment of the corresponding polyhedrin gene. Using HasNPV partial predicted polyhedrin to probe the Southern blots, we identified the location of the polyhedrin gene within the 6 kb EcoRI, 15 kb NcoI, 20 kb XhoI, 17 kb BglII and 3 kb ClaI fragments, respectively. The 3 kb ClaI fragment was cloned and the nucleotide sequences of the polyhedrin coding region and its flaking regions were determined. Nucleotide sequence analysis indicated the presence of an open reading frame of 735 nucleotides which could encode 245 amino acids with a predicted molecular mass of 29 kDa. The nucleotide sequences within the coding region of HasNPV polyhedrin shared 73.7% identity with the polyhedrin gene from Autographa californica NPV but were most closely related to Helicoverpa and Heliothis species NPVs with over 99% sequence identity.

  10. Testes and chromosomes in interspecific hybrids between Helicoverpa armigera (Hübner) and Helicoverpa assulta (Guenée)

    Institute of Scientific and Technical Information of China (English)

    TANG Qingbo; YAN Yunhua; ZHAO Xincheng; WANG Chenzhu

    2005-01-01

    The interspecific hybridization between Helicoverpa armigera females and Helicoverpa assulta males yielded F1 hybrids (RS), fertile males and sterile individuals with abnormal genitals. The reverse hybridization between H. assulta females and H. armigera males yielded F1 hybrids (SR)――fertile males and fertile females. The morphology of testes and the karyotype of chromosomes of larvae in the hybrids were investigated. Among the 2d old fifth-instar SR larvae, individuals without testes were fertile females and those with testes were fertile males. The length and breadth of testes between SR and parental species were not significantly different (p>0.05). Among the 2d old fifth-instar RS larvae, the testes were observed in all the individuals, but it could be classified into two types. The length and the breadth of testes in Type 1 larvae were not significantly different from those of their parental species (p>0.05), while those in Type 2 were significantly less than those of their parental species (p<0.01). Mitotic metaphase I of brain cells showed the diploid chromosomes number of both reciprocal hybrids was 2n=62, as many as their parents. The haploid number of 31 was confirmed by counts from spermatocytes at meiotic metaphase from SR male larvae and Type 1 larvae of RS. Meiosis was not observed in spermatocytes of Type 2 larvae of RS. Considering the characteristics of adult hybrids of RS, it was concluded that Type 1 individuals in RS were fertile and those of Type 2 were sterile. The sterility of Type 2 individuals in RS is attributed to the abnormity in development of testes and the failing meiosis of spermatocytes. As a result, the normal spermatozoon could not been produced.

  11. 烟夜蛾血淋巴凝集素活性的研究%Hemagglutination activity of lectins in the hemolymph of Helicoverpa assulta

    Institute of Scientific and Technical Information of China (English)

    张利芬; 白素芬; 李欣

    2013-01-01

    利用血凝法检测烟夜蛾Helicoverpa assulta血淋巴对红细胞的凝集活性和不同发育期凝集素水平,同时选取13种糖进行凝集素糖抑制反应,以明确该凝集素与烟夜蛾发育的关系和糖结合特性.研究结果表明,在烟夜蛾的不同发育期均检测有凝集素,但各龄幼虫及不同日龄蛹的凝集活性存在明显差异,雌蛹凝集素水平高于同日龄的雄蛹,表明凝集素与发育期、虫龄及蜕皮过程有关,且与性别相关.烟夜蛾蛹血淋巴凝集素活性与近缘种棉铃虫H.armigera的相类似,均被D-半乳糖、L-鼠李糖、麦芽糖、乳糖明显抑制;D-葡萄糖、D-果糖、L-岩藻糖和蔗糖等也有抑制作用,但抑制程度不同;L-阿拉伯糖与棉铃虫凝集素的专一性结合更强;N-乙酰葡萄糖胺和L-山梨糖只对棉铃虫凝集素有抑制作用,而对烟夜蛾凝集素无抑制作用,说明这2个近缘种的凝集素不完全相同.%To understand the relationship between lectins and development in H.assulta,and the sugar-binding specificity of H.assulta lectin,Hemagglutination assays were used to determine the hemagglutinating activity (HA) of haemolymph extracted from Helicoverpa assulta to the erythrocytes,and the changes of HA titer during different developmental stages of H.assulta.Meanuhile,thirteen sugars were tested to determine their inhibitory effect on H.assulta lectin.The results showed that lectins were detected during all developmental stages of H.assulta.Hemagglutination activity (HA) titer fluctuated between and within the various developmental stages,particularly in different larval instars and pupal ages,female pupal H.assulta had higher HA titer than their male cohorts.These results indicated that HA of lectins may be related to developmental stage,larval instar and molting process,and was dependent on sex.The carbohydrate binding specificity of the lectins in pupal hemolymph from H.assulta and H.armigera was determined by

  12. 贵州省烟青虫遗传多样性%Genetic Diversity ofHelicoverpa assulta (Lepidoptera:Noctuidae) in Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    师沛琼; 杨茂发; 吕召云; 李尚伟; 廖启荣; 商胜华; 徐进; 吴怡蓓

    2014-01-01

    关性。【结论】贵州省烟青虫种群具有较丰富的遗传多样性。各种群间极度分化,遗传变异主要来自种群间。地理隔离没有对种群遗传分化造成显著影响。%Objective The objectives of the study are to explore genetic differentiation of oriental tobacco budworm (Helicoverpa assulta) among different geographic populations in Guizhou, uncover the differential law and mechanism, and to provide a scientific basis for the pest monitoring and integrated control.[Method] PCR amplifications were performed by 6 pairs of SSR primers that were screened out from 43 pairs of primers from closely-related species, using DNA from 30H. assulta geographic populations in Guizhou as template. The PCR products were subjected to 8% non-denaturing polyacrylamide gelelectrophoresis and visualized by silver staining. Genetic diversity was analyzed byPopGene Version 1.32, and the UPGMA dendrogram was constructed by using MEGA 5.0 based on the Nei’s genetic distance. The correlation between genetic and geographic distances as well as between genetic identity and elevation were analyzed by using Mantel.[Result] The observed and effective number of alleles ranged from 3 to 8 with an average of 5 and from 1.4498 to 2.2219 with an average of 1.8594, respectively. Shannon’s information index ranged from 0.5310 to 1.0609 with an average of 0.8423. The observed (Ho) and expected heterozygosity (He) varied from 0.0260 to 0.2672 with a mean of 0.1239 and from 0.3123 to 0.5520 with a mean of 0.4539, respectively. TheHe was higher than theHo, suggesting that all populations were mainly in homozygous condition.FISchanged from 0.0798 to 0.7906 with a mean of 0.2801;FIT changed from 0.4842 to 0.9731 with a mean of 0.7809. BothFISandFITwere positive, indicating that there existed inbreeding in the all populations of H. assulta from tobacco-growing areas of Guizhou.FST ranged from 0.3897 to 0.9256 and gene flow (Nm) was less than 1, which reflected high

  13. Genetic differentiation of Helicoverpa armigera (Hübner) and H.Assulta (Guenée) (Lepidoptera: Noctuidae) based on AFLP markers

    Institute of Scientific and Technical Information of China (English)

    QING-LEI MING; CHEN-ZHU WANG

    2006-01-01

    Here we use amplified fragment length polymorphism (AFLP) to assess genetic differentiation of Helicoverpa armigera and H. assulta. The results indicated that both species-specific fingerprints and cluster analysis showed the ability of AFLP technique to discriminate the two sibling species; among a total 1963 AFLP markers amplified from nine primer combinations: 777 (39.6%) were H. armigera-specific,602 (30.7%) were H. assultaspecific,and 584 (29.7%) were common bands. The mean number of H. armigera-specific bands was significantly more than that of H. assulta-specific bands for nine primer combinations (P<0.05); the intraspecific distance of H. armigera and H. assulta was 0.123 0 and 0.110 7 respectively,and the interspecific distance was 0.178 3. In addition,the percentage of polymorphic loci and estimated average heterozygosity were used to estimate genetic diversity of the two species. This study therefore demonstrates that AFLP analysis is a sensitive and reliable technique to study genetic differentiation and genetic relationships between species and provides sufficient molecular markers for future linkage map construction,location and eventual cloning of genes involved in traits differentiation.

  14. Mass rearing of the oriental tobacco budworm for sterile insect technique programs

    International Nuclear Information System (INIS)

    The main purpose of the study is to find out a proper technique for mass rearing the oriental tobacco budworm, Helicoverpa assulta Guenee. The oriental tobacco budworms larvae were reared with different formulation diets and kept in traditional glass test tubes or in specially-designed cell-unit devices. When the diets including vitamin C and tomato source, and the ratio of corn and soybean powder was set as 1:2, the pupae weight, moth weight, pupation, emergence, fecundity and hatchability were increased significantly. When reared in cell-units, there is no significant difference in insect compared with those in glass test tubes, but the production efficiency was much higher and the cost was lower than the latter. The results of this study provide a key technical support for the application of sterile insect technique in control of oriental tobacco budworm. (authors)

  15. 烟青虫幼虫味觉可塑性行为研究%Study on Taste Plasticity in Helicoverpa assulta Larva

    Institute of Scientific and Technical Information of China (English)

    周东升; 龙九妹

    2012-01-01

    [Objective] The aim was to provide a reference for pest control by studying the taste plasticity in Helicoverpa assulta, [Method] The two choices assays and taste seosilla ablation were used to investigate the taste plasticity on the deterrents in 5th instar larvae of & assula which were reared on different artificial diets. [Result] The larvae reared on normal artificial diets were sensitive to the deterrents, the caterpillars with ablation of the lateral sensillum styloconica reacted to the deterrents as normal larvae. Meantime, the caterpillars with ablation of the medial sensillum styloconica were insensitive to the deterrents.However, the caterpillars reared on the artificial diets containing low deterrents showed insensitivity to the deterrents. [Conclusion] The medial sensillum styloconica contains the taste neurons which is sensitive to deterrents and there is a taste plasticity in different food experienced caterpillars of H. assulta..c%[目的]研究烟青虫幼虫的可塑性行为,为害虫防治提供参考.[方法]采用行为试验双选法和切除味觉感受器研究了不同取食经历烟青虫5龄幼虫对取食抑制素的味觉可塑性行为.[结果]正常人工饲料饲养幼虫对取食抑制素十分敏感,切除了侧栓锥感受器的幼虫对取食抑制素的反应与正常幼虫相似,切除了中栓锥感受器的幼虫对取食抑制素不敏感.而用含有低浓度取食抑制素的人工饲料饲养的幼虫对取食抑制素不敏感.[结论]中栓锥感受器中含有对取食抑制素敏感的味觉神经元,不同取食经历的烟青虫幼虫对取食抑制素具有行为可塑性.

  16. 烟夜蛾幼虫中肠Bt Cry1Ac毒素受体蛋白cDNA片段的克隆和序列测定%Molecular Cloning and Sequencing of cDNA Fragment Encoding Bt Cry1Ac Toxin Binding Protein from the Midgut of Helicoverpa assulta Guenée Larva

    Institute of Scientific and Technical Information of China (English)

    安世恒; 郭线茹; 罗梅浩; 蒋金炜; 马继盛

    2005-01-01

    利用RT-PCR技术扩增烟夜蛾(Helicoverpa assulta Guenée)幼虫中肠Bt毒素Cry1Ac受体蛋白APN(N-氨基肽酶,aminopeptidase N,APN)基因片段,克隆和测序结果表明,测序得到的812 bp的片段编码270个氨基酸残基,且该片段在阅读框内.通过同源性分析发现,其核苷酸序列与棉铃虫(H. armigera)、澳洲棉铃虫(H. punctigera)、烟芽夜蛾(H. virescens)、舞毒蛾(Lymantria dispar)、小菜蛾(Plutella xylostella)、印度谷螟(Plodia interpunctella)RC688品系和HD198品系、烟草天蛾(Manduca sexta)和家蚕(Bombyx mori)的Cry1Ac受体蛋白基因的同源性分别为97.0%,90.0%,78.0%,63.5%,55.0%,60.3%,61.2%,55.0%和59.0%.推导的烟夜蛾Cry1Ac受体蛋白基因的氨基酸序列与棉铃虫、烟芽夜蛾、斑实夜蛾、舞毒蛾的氨基酸序列同源性分别为95.6%,81.0%,82.7%和55.7%.该片段编码的氨基酸属于氨肽酶家族,与烟夜蛾对Bt Cry1Ac毒素的抗性有关.

  17. Interpretation of the biological species concept from interspecific hybridization of two Helicoverpa species

    Institute of Scientific and Technical Information of China (English)

    WANG ChenZhu

    2007-01-01

    The biological species concept defines species in terms of interbreeding. Interbreeding between species is prevented by reproductive isolation mechanisms. Based on our results of interspecific hybridization between Helicoverpa armigera and Helicoverpa assulta, reproductive isolation mechanisms of the two species are analyzed. A combination of prezygotic factors (absent sex attraction and physical incompatibility of the genitalia) and postzygotic factors (female absence and partial sterility in F1 hybrids) causes reproductive isolation of the two species. In addition, the role of interspecific hybridization in speciation is discussed.

  18. A new name for the western spruce budworm (Lepidoptera: Tortricidae)?

    Science.gov (United States)

    There currently is considerable confusion as to the correct application of the name Choristoneura occidentalis. This name has historically been applied to the western spruce budworm, a serious forest pest in western North America. However, Razowski (2008) transferred Archips occidentalis into Choris...

  19. Expression in antennae and reproductive organs suggests a dual role of an odorant-binding protein in two sibling Helicoverpa species.

    Directory of Open Access Journals (Sweden)

    Ya-Lan Sun

    Full Text Available Odorant-binding proteins (OBPs mediate both perception and release of semiochemicals in insects. These proteins are the ideal targets for understanding the olfactory code of insects as well as for interfering with their communication system in order to control pest species. The two sibling Lepidopteran species Helicoverpa armigera and H. assulta are two major agricultural pests. As part of our aim to characterize the OBP repertoire of these two species, here we focus our attention on a member of this family, OBP10, particularly interesting for its expression pattern. The protein is specifically expressed in the antennae of both sexes, being absent from other sensory organs. However, it is highly abundant in seminal fluid, is transferred to females during mating and is eventually found on the surface of fertilised eggs. Among the several different volatile compounds present in reproductive organs, OBP10 binds 1-dodecene, a compound reported as an insect repellent. These results have been verified in both H. armigera and H. assulta with no apparent differences between the two species. The recombinant OBP10 binds, besides 1-dodecene, some linear alcohols and several aromatic compounds. The structural similarity of OBP10 with OBP1 of the mosquito Culex quinquefasciatus, a protein reported to bind an oviposition pheromone, and its affinity with 1-dodecene suggest that OBP10 could be a carrier for oviposition deterrents, favouring spreading of the eggs in these species where cannibalism is active among larvae.

  20. Forest dynamics after successive spruce budworm outbreaks in mixedwood forests.

    Science.gov (United States)

    Bouchard, Mathieu; Kneeshaw, Daniel; Bergeron, Yves

    2006-09-01

    In order to assess the long-term spatiotemporal influence of the spruce budworm in sub-boreal mixedwood forests, we studied the effect of three successive outbreaks in a region of western Quebec, Canada. We used dendrochronology to detect past outbreaks in three areas (111-185 ha), based on the recruitment age of balsam fir (Abies balsamea) and on growth patterns of white spruce (Picea glauca), the two main host species of this defoliating insect. We also used a series of aerial photographs taken between 1935 and 2003 to evaluate overstory mortality and post-outbreak succession patterns in these same areas. Individual outbreaks had a spatially homogenous impact on host species throughout the region, but successive outbreaks differed in intensity: the two outbreaks around 1910 and 1980 caused widespread mortality in the overstory, but an outbreak around 1945 had little impact, probably because the forest mosaic had not yet recuperated from the 1910 outbreak. No clear outbreak was detected in the later part of the 19th century. In portions of the study areas where the 1910 outbreak had a major impact, between 36% and 50% of the stands were reoccupied by balsam fir stands in the period up to the 1980 outbreak (cyclic succession), the rest being at least partly replaced by nonhost species such as Betula spp. Changes in forest composition after the 1910 outbreak were mostly associated with upper-slope positions in all study areas. The 1980 outbreak also had a higher impact than earlier outbreaks in lower-slope positions dominated by black spruce (Picea mariana)-balsam fir mixtures. These results suggest that, at the regional scale, the abundance of mature or over-mature balsam fir stands does not determine the outbreak cycle. When an outbreak occurs, however, its impact will be strongly constrained by forest characteristics such as stand composition and structure, which are themselves influenced by previous disturbances and slope position.

  1. Comparing modern and presettlement forest dynamics of a subboreal wilderness: Does spruce budworm enhance fire risk?

    Science.gov (United States)

    Sturtevant, Brian R.; Miranda, Brian R.; Shinneman, Douglas J.; Gustafson, Eric J.; Wolter, Peter T.

    2012-01-01

    Insect disturbance is often thought to increase fire risk through enhanced fuel loadings, particularly in coniferous forest ecosystems. Yet insect disturbances also affect successional pathways and landscape structure that interact with fire disturbances (and vice-versa) over longer time scales. We applied a landscape succession and disturbance model (LANDIS-II) to evaluate the relative strength of interactions between spruce budworm (Choristoneura fumiferana) outbreaks and fire disturbances in the Boundary Waters Canoe Area (BWCA) in northern Minnesota (USA). Disturbance interactions were evaluated for two different scenarios: presettlement forests and fire regimes vs. contemporary forests and fire regimes. Forest composition under the contemporary scenario trended toward mixtures of deciduous species (primarily Betula papyrifera and Populus spp.) and shade-tolerant conifers (Picea mariana, Abies balsamea, Thuja occidentalis), with disturbances dominated by a combination of budworm defoliation and high-severity fires. The presettlement scenario retained comparatively more “big pines” (i.e., Pinus strobus, P. resinosa) and tamarack (L. laricina), and experienced less budworm disturbance and a comparatively less-severe fire regime. Spruce budworm disturbance decreased area burned and fire severity under both scenarios when averaged across the entire 300-year simulations. Contrary to past research, area burned and fire severity during outbreak decades were each similar to that observed in non-outbreak decades. Our analyses suggest budworm disturbances within forests of the BWCA have a comparatively weak effect on long-term forest composition due to a combination of characteristics. These include strict host specificity, fine-scaled patchiness created by defoliation damage, and advance regeneration of its primary host, balsam fir (A. balsamea) that allows its host to persist despite repeated disturbances. Understanding the nature of the three-way interaction

  2. Commercial production of transgenic Bt insect-resistant cotton varieties and the resistance management for bollworm (Helicoverpa armigera Hubner)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There are currently three kinds of transgenic Bt insect-resistant cotton germplasm lines, Shanxi 94-24, Zhongxin 94 and R19, in China. They showed high resistance to the neonate larvae of bollworm (Helicoverpa armigera). Transgenic Bt insect-resistant cotton varieties or hybrids have been bred using the three kinds of germplasm lines as parents. Our researches reveal that there exist different expressions in resistant level at different developmental stages in the three categories of germplasm lines. When neonate larvae are fed with leaves of cotton plant at the seeding stage with less than 10 leaves on the main stem, the mortality of the neonate larvae is 100%, but the resistance level will decline at later season. When Bt gene has been transferred to the cotton genome, it can be steadily transferred to the progeny, the level of resistance to bollworm keeps fundamentally uniform. Such insects as tobacco budworm (Heliothis virencens) in laboratory directive selection are very apt to produce resistance to the Bt insecticidal crystal protein. From the present crop system of cotton region in the Yangtze and Yellow River Valleys, and the expression characteristic of transgenic Bt resistant cotton, we suggest that the resistance to toxin protein in bollworm is not apt to be produced if the transgenic Bt insect-resistant cotton varieties are released and grown in the regions except in the Xinjiang cotton region. The managing strategies to delay or retard the resistance are discussed.

  3. Interspecific variation in resistance of two host tree species to spruce budworm

    Science.gov (United States)

    Fuentealba, Alvaro; Bauce, Éric

    2016-01-01

    Woody plants regularly sustain biomass losses to herbivorous insects. Consequently, they have developed various resistance mechanisms to cope with insect attack. However, these mechanisms of defense and how they are affected by resource availability are not well understood. The present study aimed at evaluating and comparing the natural resistance (antibiosis and tolerance) of balsam fir (Abies balsamea [L.] Mill.) and white spruce (Picea glauca [Moench) Voss] to spruce budworm, Choristoneura fumiferana (Clem.), and how drainage site quality as a component of resource availability affects the expression of resistance over time (6 years). Our results showed that there are differences in natural resistance between the two tree species to spruce budworm, but it was not significantly affected by drainage quality. Balsam fir exhibited higher foliar toxic secondary compounds concentrations than white spruce in all drainage classes, resulting in lower male pupal mass, survival and longer male developmental time. This, however, did not prevent spruce budworm from consuming more foliage in balsam fir than in white spruce. This response suggests that either natural levels of measured secondary compounds do not provide sufficient toxicity to reduce defoliation, or spruce budworm has developed compensatory mechanisms, which allow it to utilize food resources more efficiently or minimize the toxic effects that are produced by its host's defensive compounds. Larvae exhibited lower pupal mass and higher mortality in rapidly drained and subhygric sites. Drainage class also affected the amount of foliage destroyed but its impact varied over the years and was probably influenced by climatic variables. These results demonstrate the complexity of predicting the effect of resource availability on tree defenses, especially when other confounding environmental factors can affect tree resource allocation and utilization.

  4. Automated detection and mapping of crown discolouration caused by jack pine budworm with 2.5 m resolution multispectral imagery

    Science.gov (United States)

    Leckie, Donald G.; Cloney, Ed; Joyce, Steve P.

    2005-05-01

    Jack pine budworm ( Choristoneura pinus pinus (Free.)) is a native insect defoliator of mainly jack pine ( Pinus banksiana Lamb.) in North America east of the Rocky Mountains. Periodic outbreaks of this insect, which generally last two to three years, can cause growth loss and mortality and have an important impact ecologically and economically in terms of timber production and harvest. The jack pine budworm prefers to feed on current year needles. Their characteristic feeding habits cause discolouration or reddening of the canopy. This red colouration is used to map the distribution and intensity of defoliation that has taken place that year (current defoliation). An accurate and consistent map of the distribution and intensity of budworm defoliation (as represented by the red discolouration) at the stand and within stand level is desirable. Automated classification of multispectral imagery, such as is available from airborne and new high resolution satellite systems, was explored as a viable tool for objectively classifying current discolouration. Airborne multispectral imagery was acquired at a 2.5 m resolution with the Multispectral Electro-optical Imaging Sensor (MEIS). It recorded imagery in six nadir looking spectral bands specifically designed to detect discolouration caused by budworm and a near-infrared band viewing forward at 35° was also used. A 2200 nm middle infrared image was acquired with a Daedalus scanner. Training and test areas of different levels of discolouration were created based on field observations and a maximum likelihood supervized classification was used to estimate four classes of discolouration (nil-trace, light, moderate and severe). Good discrimination was achieved with an overall accuracy of 84% for the four discolouration levels. The moderate discolouration class was the poorest at 73%, because of confusion with both the severe and light classes. Accuracy on a stand basis was also good, and regional and within stand

  5. Genomics and genetic engineering of Helicoverpa armigera nucleopolyhedroviruses

    NARCIS (Netherlands)

    Chen, X.

    2001-01-01

    The single nucleocapsid nucleopolyhedrovirus (SNPV) of the bollworm Helicoverpa armigera has been extensively used to control this insect around the world, especially in China. However, in order to compete with chemical insecticides - mainly for speed of action -novel approaches are sought to improv

  6. Benefit-cost analysis of spruce budworm (Choristoneura fumiferana Clem.) control: incorporating market and non-market values.

    Science.gov (United States)

    Chang, Wei-Yew; Lantz, Van A; Hennigar, Chris R; MacLean, David A

    2012-01-01

    This study employs a benefit-cost analysis framework to estimate market and non-market benefits and costs of controlling future spruce budworm (Choristoneura fumiferana) outbreaks on Crown forest lands in New Brunswick, Canada. We used: (i) an advanced timber supply model to project potential timber volume saved, timber value benefits, and costs of pest control efforts; and (ii) a recent contingent valuation method analysis that evaluated non-market benefits (i.e., changes in recreation opportunities and existence values) of controlling future spruce budworm outbreaks in the Province. A total of six alternative scenarios were evaluated, including two uncontrolled future budworm outbreak severities (moderate vs. severe) and, for each severity, three control program levels (protecting 10%, 20%, or 40% of the susceptible Crown land forest area). The economic criteria used to evaluate each scenario included benefit-cost ratios and net present values. Under severe outbreak conditions, results indicated that the highest benefit-cost ratio (4.04) occurred when protecting 10% (284,000 ha) of the susceptible area, and the highest net present value ($111 M) occurred when protecting 20% (568,000 ha) of the susceptible area. Under moderate outbreak conditions, the highest benefit-cost ratio (3.24) and net present value ($58.7 M) occurred when protecting 10% (284,000 ha) of the susceptible area. Inclusion of non-market values generally increased the benefit-cost ratios and net present values of the control programs, and in some cases, led to higher levels of control being supported. Results of this study highlight the importance of including non-market values into the decision making process of forest pest management. PMID:22054576

  7. GENE CLONE AND SEQUENCE ANALYSIS OF 18S RIBOSOMAL DNA OF HELICOVERPA ASSULTA (GUEN(E)E)%烟夜蛾18S rDNA的克隆及序列分析

    Institute of Scientific and Technical Information of China (English)

    李海超; 乔奇; 原国辉; 郭线茹; 罗梅浩; 吴少英

    2009-01-01

    利用PCR方法克降得到了烟夜蛾18S rDNA全基因序列,基因全长1904bp;构建了其全长、保守区和非保守区的系统发育树,比较了与其他已知蛾类昆虫18S rDNA全序列的同源性.结果表明,蛾类之间该基因的同源性达到92%以上,利用其多变区构建的发育树更能反映蛾类昆虫的亲缘关系;比较烟夜蛾与棉铃虫的18S rDNA序列发现,两个近缘种之间仅有lO个核苷酸的差异.

  8. Role of Douglas fir (Pseudotsuga menziesii) carbohydrates in resistance to budworm (Choristoneura occidentalis).

    Science.gov (United States)

    Zou, J; Cates, R G

    1994-02-01

    The current year's growth of Douglas fir contains galactose, unusual in that this carbohydrate makes up 78.7% of the total carbohydrate fraction. An agar diet study was undertaken to determine the effects of galactose, other carbohydrates, and terpenes on western spruce budworm larval mortality, growth rate, and adult biomas production. All concentrations of the carbohydrates and terpenes tested, as well as other mineral elements not tested, were typical of the current year's foliage of Douglas fir. In experiment I, the diet containing 5.61% total carbohydrate did not significantly affect larval mortality when compared to the control diet. However, diets containing 9.45% and 15% total carbohydrate concentrations significantly increased larval mortality 64% and 96.1%, respectively, when compared to the control. Also in experiment I, terpenes alone (78.9% morality) and terpenes in combination with 9.45% and 15% total carbohydrates significantly increased larval mortality (97.2% and 100%, respectively) when compared to mortality on the control diet (44%). To determine which carbohydrate was causing the adverse effect, 6% glucose, 6% fructose, and 6% galactose were placed individually and in combination with terpenes in diets in experiment II. The 6% galactose diet significantly increased larval mortality and reduced growth rate when compared to the control, glucose, and fructose diets. Glucose resulted in 16% less larval mortality, significantly enhanced female larval growth rate and pupal weight, but did not affect male larval growth rate and pupal weight, when compared to the control. Fructose resulted in a significant decrease in larval mortality and a general trend of enhanced female and male larval growth rate and pupal weight. Larval mortality on terpenes alone was not significantly different from the control, but terpenes with 6% galactose increased larval mortality and decreased female and male growth rate and pupal weight significantly when compared to

  9. Evaluation of an aerial spray strategy against the spruce budworm (choristoneura fumiferana clem.) using fenitrothion and B.t., (bacillus thuringiensis): Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kettela, E.G.

    1993-12-31

    This report presents results from a series of trials to evaluate replicate test sites, two treated with fenitrothion followed by an application of Bacillus thuringiensis (B.t.) and two treated with two applications of B.t. A team of Cessna 188 aircraft equipped with Micronair AU4000 rotary atomizers applied all spray treatments; there were also unsprayed control plots for comparison. The investigators conducted biological evaluations of 60 selected balsam fir trees at each treatment site to record such information as number of buds and shoots, defoliation category for each bud/shoot, number of spruce budworms, and state of development of each bud/shoot. They also determined spray deposition. The report concludes with an assessment of the comparative efficacy of the treatments studied on spruce budworm mortality.

  10. Characterization of a new Helicoverpa armigera nucleopolyhedrovirus variant causing epizootic on a previously unreported host, Helicoverpa gelotopoeon (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Ferrelli, M L; Taibo, C; Fichetti, P; Sciocco-Cap, A; Arneodo, J D

    2016-07-01

    This paper reports the first biological and molecular characterization of a nucleopolyhedrovirus isolated from the soybean and cotton pest Helicoverpa gelotopoeon. Studies were performed following a virus outbreak in a rearing facility and in wild H. gelotopoeon populations in Córdoba, Argentina. Host identity was corroborated by partial sequencing of the COI gene. Scanning electron microscope observations of purified OBs revealed their polyhedral morphology and an average diameter of 0.89±0.14μm. Ultrathin sections of infected larvae examined by transmission electron microscopy showed the intranuclear occurrence of polyhedra and virus particles in fat body cells. Nucleocapsids were singly enveloped. Phylogenetic analysis of lef-8, lef-9, polh, orf5/5b and hr3-orf62 viral sequences identified this new NPV isolate (hereafter HegeSNPV) as a variant of Helicoverpa armigera nucleopolyhedrovirus (HearNPV). Furthermore, HegeSNPV was closely related to the so-called "HzSNPV Group" within HearNPV, although having particular characteristics. PMID:26296927

  11. Case history of population change in a `bacillus thuringiensis`-treated versus an untreated outbreak of the western spruce budworm. Forest Service research note

    Energy Technology Data Exchange (ETDEWEB)

    Mason, R.R.; Paul, H.G.

    1996-09-01

    Larval densities of the western spruce budworm (Choristoneura occidentalis Freeman) were monitored for 12 years (1984-95) on permanent sample plots in northeastern Oregon. The time series spanned a period of general budworm infestations when populations increased rapidly from low densities, plateaued for a time at high-outbreak densities, and then declind suddenly. Midway through the period (1988), an area with half of the sample plots was sprayed with the microbial insecticide Bacillus thuringiensis (B.t.) in an operational suppression project. The other sample plots were part of an untreated area. In the treated area, B.t. spray reduced numbers of larvae by more than 90 percent; however, populations returned to an outbreak density within 3 years. In the untreated area, populations remained at outbreak densities and continued to fluctuate due to natural feedback processes. Natural decline of the population (1992-95) in the monitored area was largely unexplained and coincided with an overall collapse of the budworm outbreak in the Blue Mountains.

  12. Candidate olfaction genes identified within the Helicoverpa armigera Antennal Transcriptome.

    Directory of Open Access Journals (Sweden)

    Yang Liu

    Full Text Available Antennal olfaction is extremely important for insect survival, mediating key behaviors such as host preference, mate choice, and oviposition site selection. Multiple antennal proteins are involved in olfactory signal transduction pathways. Of these, odorant receptors (ORs and ionotropic receptors (IRs confer specificity on olfactory sensory neuron responses. In this study, we identified the olfactory gene repertoire of the economically important agricultural pest moth, Helicoverpa armigera, by assembling the adult male and female antennal transcriptomes. Within the male and female antennal transcriptomes we identified a total of 47 OR candidate genes containing 6 pheromone receptor candidates. Additionally, 12 IR genes as well as 26 odorant-binding proteins and 12 chemosensory proteins were annotated. Our results allow a systematic functional analysis across much of conventional ORs repertoire and newly reported IRs mediating the key olfaction-mediated behaviors of H. armigera.

  13. Cloning, expression and localization of a trypsin-like serine protease in the spruce budworm, Choristoneura fumiferana

    Institute of Scientific and Technical Information of China (English)

    Wen-Ying He; Yi-Ping Zheng; Lin Tang; Si-Chun Zheng; Catherine Béliveau; Daniel Doucet; Michel Cusson; Qi-Li Feng

    2009-01-01

    A trypsin-like molting-related serine protease cDNA (CfMRSP) was cloned from the spruce budworm, Choristoneura fumiferana. The full-length CfMRSP comple-mentary DNA (cDNA) encoded a 43 kDa protein that contained a trypsin-like serine protease catalytic domain, but no clip domain. The C-terminal extension contained five cystein residues, which may allow the protein to form a homodimer through interchain disulfide bonds and regulate the activity of CfMRSP. Phylogenetic tree analysis showed that CfMRSP clusters with lepidopteran homologues such as serine protease 1 of Lonomia obliqua, hemolymph proteinase 20 (HP20), pattern recognition serine proteinase precursor (ProHP14) and a trypsin-like protein of Manduca sexta. Northern blot analysis of devel-opmental expression of CfMRSP indicated that its transcripts were found primarily in the epidermis and were produced during all of the tested stadia, from 4th instar larvae to pupae, but increased levels of C/MRSP transcripts were always found after each molt. A high level of the protein was found in the epidermis by immunohistochemistry analysis. Altogether these data suggest that CfMRSP plays a role in the epidermis during molting and metamorphosis.

  14. Remote sensing of spruce budworm defoliation using EO-1 Hyperion hyperspectral data: an example in Quebec, Canada

    Science.gov (United States)

    Huang, Z.; Zhang, Y.

    2016-04-01

    Each year, the spruce budworm (SBW) causes severe, widespread damage to spruces and fir in east coast Canada. Early estimation of the defoliation can provide crucial support to mitigate the socio-economic impact on vulnerable forests. Remote sensing techniques are suitable to investigate the affected regions that usually consist of large and inaccessible forestry areas. Using satellite images, surface reflectance values at two or more wavelengths are combined to generate vegetation indices (VIs), revealing a relative abundance of features of interest. Forest health analysis based on VIs is considered as one of the primary information sources for monitoring vegetation conditions. Especially the spectral resolution of Hyperion hyperspectral satellite imagery used in this study allows for a detailed examination of the red to near-infrared portion of the spectrum to identify areas of stressed vegetation. Several narrow-band vegetation indices are used to indicate the overall amount and quality of photosynthetic material and moisture content in vegetation. By integrating the information from VIs that focus on different aspects of overall health and vigour in forested areas, the study aims at detecting defoliated condition in a forested region in the Province of Quebec, Canada. In June and August of 2014 two Hyperion images were acquired by NASA's EO-1 satellite for this study. Changes in vegetation health and vigour are observed and quantitatively compared using the multi-temporal remote sensing images. The experimental results suggest that the VI- based forest health analysis is effective in estimating SBW defoliation in the study area.

  15. Effects of climate change on fire and spruce budworm disturbance regimes and consequences on forest biomass production in eastern Canada

    International Nuclear Information System (INIS)

    The dynamics of spruce budworm (SBW) outbreaks and wildfires are expected to change as climatic change progresses. The effects of an altered, combined interaction between SBW and fire may be of greater importance than the individual effect of either on forest biomass production. The objectives of this study are to define current fire and SBW regimes in eastern Canada and relate the characteristics of each regime based upon climate model outputs for 2050 and 2100. The study also attempts to evaluate the impact of predicted changes in SBW and fire disturbance regimes on forest dynamics. The methodology used in the study included data from the Canadian Large Fire Database and historical records of SBW outbreaks. Spatial and environmental variables were presented along with climate models. The analysis was conducted using constrained ordination techniques, and canonical correspondence and redundancy analysis. Projected disturbance regimes were presented for both fire and SBW. The effects of the regimes on biomass productivity were also examined, using a Landscape Disturbance Simulator (LAD). It was concluded that this model will help evaluate the consequences of changes imposed by climatic change on both disturbances individually, as well as their interaction. 10 refs., 1 tab., 2 figs

  16. Combining Tpi and CO1 Genetic Markers to Discriminate Invasive Helicoverpa armigera From Local Helicoverpa zea (Lepidoptera: Noctuidae) Populations in the Southeastern United States.

    Science.gov (United States)

    Nagoshi, Rodney N; Gilligan, Todd M; Brambila, Julieta

    2016-10-01

    The recent establishment of the Old World pest Helicoverpa armigera (Hübner) into South America has had significant economic consequences and places the rest of the hemisphere at risk, emphasizing the need for improved methods of monitoring. A major complication is that a sibling species endemic to the New World, Helicoverpa zea (Boddie), is morphologically very similar, with the two species capable of producing fertile hybrids in the laboratory. The consequences of such hybridization in the field are uncertain, but could result in significant and unpredictable changes in the timing, range, and pesticide susceptibilities of Helicoverpa infestations. The objective here is to provide new genetic resources applicable to Helicoverpa populations in northern Florida and neighboring states (a region at risk for H. armigera) that can distinguish the two species and possible hybrids. The genetic variability in segments of the mitochondrial cytochrome oxidase 1 (CO1) and the Z-linked triosephosphate isomerase (Tpi) genes were determined for H. zea from the southeastern United States. These were compared to DNA sequences from H. armigera specimens from Morocco, Australia, and Europe. Phylogenetic network analysis showed a clear demarcation between the two species for all gene segments. These results extend earlier studies establishing CO1 as marker for discriminating the Helicoverpa species complex and introduce a new sex-linked genomic marker. The CO1 and Tpi markers in combination provide a more accurate and sensitive method than existing techniques for identifying hybridization between H. zea and H. armigera and could potentially be used to extrapolate the likely source of invasive H. armigera populations.

  17. Solexa sequencing based transcriptome analysis of Helicoverpa armigera larvae.

    Science.gov (United States)

    Li, Jigang; Li, Xiumin; Chen, Yongli; Yang, Zhongxiang; Guo, Sandui

    2012-12-01

    Helicoverpa armigera (Hübner) is a polyphagous Lepidoptera pest which causes great economic losses in crop production worldwide. In contrast to its agricultural importance, advances in the molecular aspects of this insect are quite limited. In the present study, Illumina's SOLEXA sequencing was adopted to determine the transcriptome of young H. armigera larvae. About 7 gigabases of raw sequence data was generated and assembled into 116,601 contigs with an average length of 389 base pairs after data preprocess. 37,352 of these contigs were annotated by searching against Uniref 100 of UniProt database. The annotated sequences were functionally classified into three groups including biological process (15,632 sequences), cellular component (9,562 sequences) and molecular function (19,258 sequences). KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis showed that 1,409 contigs predicted to encode enzymes with enzyme commission numbers were mapped into 220 KEGG pathways in total. Finally, contigs with simple sequence repeats were derived from this dataset. PMID:23065207

  18. Natural control of Helicoverpa armigera in smallholder crops in East Africa.

    NARCIS (Netherlands)

    Berg, van de H.

    1993-01-01

    The African bollworm, Helicoverpa (=Heliothis) armigera , is one of the worst agricultural pests in Africa, attacking a variety of food and cash crops. For development of sustainable pest management, it is essential to study the ecology and natural mortality factors of the pest, and recently, the ne

  19. A new gland associated with the retrocerebral complex of the adult corn earworm, Helicoverpa zea

    Science.gov (United States)

    We report the discovery of a putative new gland associated with the retrocerebral complex in the adults of Helicoverpa zea. The gland was not observed in Manduca sexta and few other species of moths. The pair of glands, each 40-60 µm in diameter, is located on either side of the recurrent nerve. Eac...

  20. Bioactivity of non-edible oil seed extracts and purified extracts against Helicoverpa armigera (Hubner).

    Science.gov (United States)

    Pawar, Pushpa; Joseph, Mary; Tungikar, Vijay; Joshi, Swati

    2004-01-01

    Extracts and purified extracts of seeds of two plant species, Madhuca latifolia and Calophyllum inophyllum when evaluated against the 2nd instar larvae of Helicoverpa armigera reared on synthetic diet, exhibited high larval mortality, prolongation of developmental period, morphological deformities and highly significant reduction in adult emergence. The reduction in larval weights in the treatments was also highly significant. PMID:15274488

  1. Long distance migration in Helicoverpa zea: What we know and need to know

    Science.gov (United States)

    This paper identifies knowledge and knowledge gaps in the areas of biology and ecology, and migratory flight of corn earworm, Helicoverpa zea (Boddie). The paper focuses on results from studies of H. zea population dynamics and migration in Texas during a period of substantial irrigated corn produc...

  2. Carbon dioxide receptor genes in cotton bollworm Helicoverpa armigera

    Science.gov (United States)

    Xu, Wei; Anderson, Alisha

    2015-04-01

    Carbon dioxide (CO2) is important in insect ecology, eliciting a range of behaviours across different species. Interestingly, the numbers of CO2 gustatory receptors (GRs) vary among insect species. In the model organism Drosophila melanogaster, two GRs (DmelGR21a and DmelGR63a) have been shown to detect CO2. In the butterfly, moth, beetle and mosquito species studied so far, three CO2 GR genes have been identified, while in tsetse flies, four CO2 GR genes have been identified. In other species including honeybees, pea aphids, ants, locusts and wasps, no CO2 GR genes have been identified from the genome. These genomic differences may suggest different mechanisms for CO2 detection exist in different insects but, with the exception of Drosophila and mosquitoes, limited attention has been paid to the CO2 GRs in insects. Here, we cloned three putative CO2 GR genes from the cotton bollworm Helicoverpa armigera and performed phylogenetic and expression analysis. All three H. armigera CO2 GRs (HarmGR1, HarmGR2 and HarmGR3) are specifically expressed in labial palps, the CO2-sensing tissue of this moth. HarmGR3 is significantly activated by NaHCO3 when expressed in insect Sf9 cells but HarmGR1 and HarmGR2 are not. This is the first report characterizing the function of lepidopteran CO2 receptors, which contributes to our general understanding of the molecular mechanisms of insect CO2 gustatory receptors.

  3. Demographics and genetic variability of the new world bollworm (Helicoverpa zea) and the old world bollworm (Helicoverpa armigera) in Brazil.

    Science.gov (United States)

    Leite, Natália A; Alves-Pereira, Alessandro; Corrêa, Alberto S; Zucchi, Maria I; Omoto, Celso

    2014-01-01

    Helicoverpa armigera is one of the primary agricultural pests in the Old World, whereas H. zea is predominant in the New World. However, H. armigera was first documented in Brazil in 2013. Therefore, the geographical distribution, range of hosts, invasion source, and dispersal routes for H. armigera are poorly understood or unknown in Brazil. In this study, we used a phylogeographic analysis of natural H. armigera and H. zea populations to (1) assess the occurrence of both species on different hosts; (2) infer the demographic parameters and genetic structure; (3) determine the potential invasion and dispersal routes for H. armigera within the Brazilian territory; and (4) infer the geographical origin of H. armigera. We analyzed partial sequence data from the cytochrome c oxidase subunit I (COI) gene. We determined that H. armigera individuals were most prevalent on dicotyledonous hosts and that H. zea were most prevalent on maize crops, based on the samples collected between May 2012 and April 2013. The populations of both species showed signs of demographic expansion, and no genetic structure. The high genetic diversity and wide distribution of H. armigera in mid-2012 are consistent with an invasion period prior to the first reports of this species in the literature and/or multiple invasion events within the Brazilian territory. It was not possible to infer the invasion and dispersal routes of H. armigera with this dataset. However, joint analyses using sequences from the Old World indicated the presence of Chinese, Indian, and European lineages within the Brazilian populations of H. armigera. These results suggest that sustainable management plans for the control of H. armigera will be challenging considering the high genetic diversity, polyphagous feeding habits, and great potential mobility of this pest on numerous hosts, which favor the adaptation of this insect to diverse environments and control strategies.

  4. Demographics and genetic variability of the new world bollworm (Helicoverpa zea and the old world bollworm (Helicoverpa armigera in Brazil.

    Directory of Open Access Journals (Sweden)

    Natália A Leite

    Full Text Available Helicoverpa armigera is one of the primary agricultural pests in the Old World, whereas H. zea is predominant in the New World. However, H. armigera was first documented in Brazil in 2013. Therefore, the geographical distribution, range of hosts, invasion source, and dispersal routes for H. armigera are poorly understood or unknown in Brazil. In this study, we used a phylogeographic analysis of natural H. armigera and H. zea populations to (1 assess the occurrence of both species on different hosts; (2 infer the demographic parameters and genetic structure; (3 determine the potential invasion and dispersal routes for H. armigera within the Brazilian territory; and (4 infer the geographical origin of H. armigera. We analyzed partial sequence data from the cytochrome c oxidase subunit I (COI gene. We determined that H. armigera individuals were most prevalent on dicotyledonous hosts and that H. zea were most prevalent on maize crops, based on the samples collected between May 2012 and April 2013. The populations of both species showed signs of demographic expansion, and no genetic structure. The high genetic diversity and wide distribution of H. armigera in mid-2012 are consistent with an invasion period prior to the first reports of this species in the literature and/or multiple invasion events within the Brazilian territory. It was not possible to infer the invasion and dispersal routes of H. armigera with this dataset. However, joint analyses using sequences from the Old World indicated the presence of Chinese, Indian, and European lineages within the Brazilian populations of H. armigera. These results suggest that sustainable management plans for the control of H. armigera will be challenging considering the high genetic diversity, polyphagous feeding habits, and great potential mobility of this pest on numerous hosts, which favor the adaptation of this insect to diverse environments and control strategies.

  5. Immune responses of Helicoverpa armigera to different kinds of pathogens

    Directory of Open Access Journals (Sweden)

    Zhao Xiao-Fan

    2010-03-01

    Full Text Available Abstract Background Insects react against pathogens through innate immunity. The cotton bollworm Helicoverpa armigera (H. armigera is an important defoliator and an extremely destructive pest insect of many crops. The elucidation of the mechanism of the immune response of H. armigera to various pathogens can provide a theoretical basis for new approaches to biologically control this pest. Results Four kinds of pathogens Bacillus thuringiensis, Klebsiella pneumoniae, Candida albicans, and Autographa californica multiple nucleocapsid nucleopolyhedrovirus harbored green fluorescence protein and polyhedron (AcMNPV-GFP were used to challenge the insect. The cellular and humoral immune responses to the pathogens were analyzed in the challenged H. armigera. The results show that in the five kinds of haemocytes, only granulocytes phagocytized the Gram-negative and Gram-positive bacteria and fungi. All haemocytes can be infected by AcMNPV. Fourteen immune-related genes including pattern recognition receptors (PRRs such as peptidoglycan recognition proteins (HaPGRP and HaPGRP C and Gram-Negative Bacteria-Binding Protein (HaGNBP, and antimicrobial peptides (AMPs such as cecropin-1, 2 and 3 (HaCec-1, 2 and 3, lysozyme (HaLys, attacin (HaAtt, gallerimycin-like (HaGall, gloverin-like (HaGlo, moricin-like (HaMor, cobatoxin-like (HaCob, galiomicin-like (HaGali, and immune inducible protein (HaIip appeared in different expression profiles to different pathogen infections. The transcripts of 13 immune related genes (except HaPGRPC are obviously up-regulated by Gram-positive bacteria. HaCec-1 and 3, HaMor, HaAtt, HaLys, HaIip, HaPGRP and HaGNBP are greatly up-regulated after fungal infection. HaGNBP, HaCec-2, HaGall, HaGlo, HaMor, HaCob, HaGali obviously increased in Gram-negative bacterial infection. Only five genes, HaGNBP, HaCec-1, HaGali, HaGlo, and HaLys, are weakly up-regulated after viral infection. The AMP transcripts had higher expression levels than the

  6. The effects of radiation on the biology and reproduction of Helicoverpa armigera (Lepidoptera: Noctuidae)

    International Nuclear Information System (INIS)

    The effect of irradiating male Helicoverpa armigera with a substerilizing dose (100 Gy) of gamma radiation on the growth, development and reproduction of subsequent generations was studied in the laboratory. This dose of gamma radiation had no significant detrimental effects on larval and pupal weights or on the duration of the pupal period in the F1 progeny. However, it lengthened the duration of the larval period by two days. In the F2 generation, the progeny of the Tf1FxTf1M cross had significantly lighter pupae. The effects of this substerilizing dose of radiation and of the resulting inherited sterility on the reproduction of Helicoverpa armigera were similar to those described for other species of Lepidoptera. No detrimental effects on P1 and F1 female fecundity were recorded. Crosses involving Tf1 females laid only about one half the number of eggs laid by the controls, however the range in the number of eggs laid by these females fell within the normal range for Helicoverpa armigera. Fertility of crosses involving P1 males was greatly affected; fertility in these females was only 61% of that exhibited by the controls. This deleterious effect was inherited in the F1 and F2 generations and was maximally expressed when F1 progeny of the NFxTM cross were inbred. Egg hatch was almost completely inhibited in sibling crosses while outcrosses of the F1 progeny showed a 64-70% reduction in egg hatch when compared to controls. (author)

  7. Identification of mariner-like elements belonging to the cecropia subfamily in two closely related Helicoverpa species

    Institute of Scientific and Technical Information of China (English)

    Jianjun Wang; Thomas A. Miller; Yoonseong Park

    2011-01-01

    Mariner transposons are widespread in eukaryote genomes and have been used as transposon vectors in insect transgenesis.We examined two closely related Helicoverpa species,the cotton bollworm Helicoverpa armigera and corn earworm Helicoverpa zea,for the presence of mariner-like elements (MLEs).Multiple copies of two distinct MLEs,Hamarl and Hamar2,were isolated in H.armigera,and a MLE showing a high degree of conservation to Hamarl was detected in H.zea and was named Hzmarl.These MLEs belong to the cecropia subfamily,containing indels in the transposase coding region.Sequence analysis indicated the earlier invasion of Hamarl and relatively recent activity of Hamar2.

  8. Wood Anatomy and Insect Defoliator Systems: Is there an anatomical response to sustained feeding by the western spruce budworm (Choristoneura occidentalis) on Douglas-fir (Pseudotusga menziesii)?

    Science.gov (United States)

    Axelson, Jodi; Gärtner, Holger; Alfaro, René; Smith, Dan

    2013-04-01

    The western spruce budworm (Choristoneura occidentalis Freeman) is the most widespread and destructive defoliator of coniferous forests in western North America, and has a long-term coexistence with its primary host tree, Douglas-fir (Pseudotsuga menziesii Franco). Western spruce budworm (WSB) outbreaks usually last for several years, and cause reductions in annual growth, stem defects, and regeneration delays. In British Columbia, the WSB is the second most damaging insect after the mountain pine beetle, and sustained and/or severe defoliation can result in the mortality of host trees. Numerous studies have used tree rings to reconstruct WSB outbreaks across long temporal scales, to evaluate losses in stand productivity, and examine isotope ratios. Although some studies have looked at the impacts of artificial defoliation on balsam fir in eastern North America, there has been no prior research on how WSB outbreaks affect the anatomical structure of the stem as described by intra-annual wood density and potential cell size variations. The objective of this study was to anatomically examine the response of Douglas-fir to sustained WSB outbreaks in two regions of southern British Columbia. We hypothesize that the anatomical intra-annual characteristics of the tree rings, such as cell wall thickness, latewood cell size, and/or lumen area changes during sustained WSB outbreaks. To test this hypothesis we sampled four permanent sample plots in coastal and dry interior sites, which had annually resolved defoliation data collected over a 7-12 year period. At each site diameter-at-breast height (cm), height (m), and crown position were recorded and three increment cores were extracted from 25 trees. Increment cores were prepared to permit anatomical and x-ray density analyses. For each tree, a 15µm thick micro section was cut from the radial plane. Digital images of the micro sections were captured and processed. In each annual ring, features such as cell lumen area (µm2

  9. Genome sequence of Acinetobacter sp. strain HA, isolated from the gut of the polyphagous insect pest Helicoverpa armigera.

    Science.gov (United States)

    Malhotra, Jaya; Dua, Ankita; Saxena, Anjali; Sangwan, Naseer; Mukherjee, Udita; Pandey, Neeti; Rajagopal, Raman; Khurana, Paramjit; Khurana, Jitendra P; Lal, Rup

    2012-09-01

    In this study, Acinetobacter sp. strain HA was isolated from the midgut of a fifth-instar larva of Helicoverpa armigera. Here, we report the draft genome sequence (3,125,085 bp) of this strain that consists of 102 contigs, 2,911 predicted coding sequences, and a G+C content of 41%. PMID:22933775

  10. Genetic Variation for Resistance to Bacillus thuringiensis Toxins in Helicoverpa zea (Lepidoptera: Noctuidae) in Eastern North Carolina

    Science.gov (United States)

    In order to evaluate resistance to Bacillus thuringiensis Berliner toxins, female bollworm moths, Helicoverpa zea (Boddie), were collected from four light trap locations in two eastern North Carolina counties from August-October during 2001 and 2002. Moths were allowed to oviposit, and upon hatch, ...

  11. Modelling biological control with wild-type and genetically modified baculoviruses in the Helicoverpa armigera-cotton system

    NARCIS (Netherlands)

    Sun, X.; Werf, van der W.; Bianchi, F.J.J.A.; Hu, Z.; Vlak, J.M.

    2006-01-01

    A comprehensive model was developed to simulate virus epizootics in a stage structured insect population and analyse scenarios for the biological control of cotton bollworm (CBW), Helicoverpa armigera, in cotton, using wild-type or genetically modified baculoviruses. In simulations on dosage and tim

  12. Transmission of wild-type and recombinant HaSNPV among larvae of Helicoverpa armigera (Lepidoptera: Noctuidae) on cotton.

    NARCIS (Netherlands)

    Georgievska, L.; Vries, R.S.M.; Gao, P.; Sun, X.; Cory, J.S.; Vlak, J.M.; Werf, van der W.

    2010-01-01

    Horizontal transmission of insect viruses is a key factor in their cycling in agro-ecosystems. Here we study the transmission of the baculovirus HaSNPV among larvae of Helicoverpa armigera (Hübner) in cotton. Transmission of three HaSNPV genotypes was studied from larvae infected with a single virus

  13. Behaviour of wild-type and genetically modified baculoviruses in the Helicoverpa armigera - cotton system: a simulation approach

    NARCIS (Netherlands)

    Sun, X.

    2005-01-01

    Keywords:   Helicoverpa armigera , baculovirus, genetic modification, cotton,transmissionEffect of emamectin benzoate on mortality, proboscis extension, gustation and reproduction of the corn earworm, Helicoverpa zea

    Science.gov (United States)

    Newly emerged bollworm adults, Helicoverpa zea (Boddie) require carbohydrate source from plant exudates and nectars for reproduction. Adults actively seek such feeding sites upon eclosion in their natural habitat. We wanted to evaluate this nocturnal behavior of the bollworm for potential use as a p...

  14. Experience-based behavioral and chemosensory changes in the generalist insect herbivore Helicoverpa armigera exposed to two deterrent plant chemicals

    NARCIS (Netherlands)

    Zhou, D.; Loon, van J.J.A.; Wang, C.Z.

    2010-01-01

    Behavioral and electrophysiological responses of larvae of the polyphagous moth species Helicoverpa armigera to two plant-derived allelochemicals were studied, both in larvae that had been reared on a diet devoid of these compounds and in larvae previously exposed to these compounds. In dual-choice

  15. Bioefficacy of Caesalpinia bonducella extracts against tobacco cutworm, Helicoverpa armigera (Hub.) (Lepidoptera:Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    Backiyaraj Muthusamy; Elumalai Arumugam; Kasinathan Dhamodaran; Mathivanan Thangarasu; Krishnappa Kaliyamoorthy; Elumalai Kuppusamy

    2015-01-01

    Objective: To evaluate the antifeedant, oviposition deterrent, ovicidal and larvicidal activities of benzene, dichloromethane, diethylether, ethyl acetate and methanol extracts of Indian medicinal plant, Caesalpinia bonducella (C. bonducella) at different concentrations against Lepidopteran agricultural field pest Helicoverpa armigera (Lepidoptera: Noctuidae). Methods: Antifeedant activities of the selected plant extract were studied using leaf disc no-choice method and oviposition deterrent, ovicidal and larvicidal activities were also assessed by adapting the standard protocols. Results: The antifeedant activity of C. bonducella showed significant antifeedant activity in methanol extract. Oviposition deterrency is higher in methanol extract than the other solvent extracts. Similarly, maximum egg mortality was observed in methanol leaf extract of C. bonducella Lethal concentration, LC50 value of benzene, diethylether, dichloromethane, ethyl acetate and methanol extract of C. bonducella were 470.02, 469.00, 465.47, 460.52 and 443.87 mg/L respectively. The Chi-square values are significant at P< 0.05 level. Among five solventextracts, the methanol extract was responsible for strong lethal activity observed against selected pest species. Conclusions: Results of this study show that the selected Indian medicinal plant C. bonducella could be a potent source of natural antifeedant, oviposition deterrent, ovicidal and larvicidal agent against the field pest Helicoverpa armigera.

  16. Analysis of the Genome of the Sexually Transmitted Insect Virus Helicoverpa zea Nudivius 2

    Directory of Open Access Journals (Sweden)

    Zhiqiang Lu

    2012-01-01

    Full Text Available The sexually transmitted insect virus Helicoverpa zea nudivirus 2 (HzNV-2 was determined to have a circular double-stranded DNA genome of 231,621 bp coding for an estimated 113 open reading frames (ORFs. HzNV-2 is most closely related to the nudiviruses, a sister group of the insect baculoviruses. Several putative ORFs that share homology with the baculovirus core genes were identified in the viral genome. However, HzNV-2 lacks several key genetic features of baculoviruses including the late transcriptional regulation factor, LEF-1 and the palindromic hrs, which serve as origins of replication. The HzNV-2 genome was found to code for three ORFs that had significant sequence homology to cellular genes which are not generally found in viral genomes. These included a presumed juvenile hormone esterase gene, a gene coding for a putative zinc-dependent matrix metalloprotease, and a major facilitator superfamily protein gene; all of which are believed to play a role in the cellular proliferation and the tissue hypertrophy observed in the malformation of reproductive organs observed in HzNV-2 infected corn earworm moths, Helicoverpa zea.

  17. X-ray radiation and development inhibition of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

    International Nuclear Information System (INIS)

    Effect of X-ray radiation on the development inhibition was evaluated for all stages of the life cycle of Helicoverpa armigera to determine a radiation dose for potential quarantine treatment against the insect. ED99 values for inhibition of hatching, pupation, and adult emergence from irradiated eggs were 413, 210, and 154 Gy, respectively. ED99 values for inhibition of pupation and adult emergence from irradiated larvae were 221 and 167 Gy, respectively. Pupa was the most tolerant to X-ray radiation. ED99 value for inhibition of adult emergence from irradiated pupae was as high as 2310 Gy, whereas that for inhibition of F1 egg hatching was only 66 Gy. ED99 value for inhibition of hatching of F1 eggs which were laid by irradiated adults was estimated to 194 Gy. X-ray irradiation against H. armigera is recommended as an alternative method to methyl bromide fumigation for phytosanitary treatments during quarantine. X-ray radiation dose of 200 Gy is proposed as a potential quarantine treatment dose for H. armigera eggs and larvae. - Highlights: • X-ray irradiation induced abnormal development of Helicoverpa armigera. • ED99 value for inhibition of pupation and adult emergence of irradiated egg was estimated at 210 and 154 Gy, respectively. • ED99 value for inhibition of pupation and adult emergence of irradiated larva was estimated at 221 and 167 Gy, respectively

  18. Introgression of Helicoverpa armigera Resistance from Cajanus acutifolius-a Wild Relative from Secondary Gene Pool of Pigeon Pea (Cajanus cajan)

    OpenAIRE

    Deepak R. Jadhav; Nalini Mallikarjuna; Sharma, Hari C; Kulbhushan B. Saxena

    2012-01-01

    The aim of the study was to introgress Helicoverpa armigera resistance from wild relative Cajanus acutifolius into pigeonpea, (Cajanus cajan L.), an important grain legume in South Asia, East Africa and the West Indies. Pigeonpea grain yields on farmer’s fields are quite low, largely because of damage by insect pests, of which legume pod borer Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is the important pest worldwide. Pod borer has developed high levels of resistance to chemical i...

  19. Western Spruce Budworm Outbreaks Did Not Increase Fire Risk over the Last Three Centuries: A Dendrochronological Analysis of Inter-Disturbance Synergism

    Science.gov (United States)

    Flower, Aquila; G. Gavin, Daniel; Heyerdahl, Emily K.; Parsons, Russell A.; Cohn, Gregory M.

    2014-01-01

    warming, our records show no precedent that western spruce budworm outbreaks will increase future fire risk. PMID:25526633

  1. 5种生物源杀虫剂防治辣椒烟青虫的试验研究%Experimental Study on Five Kinds of Bio-pesticides on Pepper Tobacco Budworm

    Institute of Scientific and Technical Information of China (English)

    孟兆明

    2011-01-01

    选择5种生物源杀虫剂对辣椒烟青虫进行药效试验,结果表明,0.3%印楝素乳油,1.8%阿维菌素乳油,2.5%多杀菌素悬浮剂,1.5%除虫菊素水剂防治烟青虫具有很好的效果,药后持效期较长,药后7~10d防治效果达到最大值,且对作物安全无药害.推荐用药量300~600 mL/hm2,叶面均匀喷雾,用药间隔期15d.%Five kinds of bio-pesticides were selected to conduct efficacy test on tobacco budworm. The results showed that, 0.3% Azadirachtin,1.8% Abamectin,2.5% Spinosad.and 1.5% pyrethrum had good control effects and long efficacy period on tobacco budworm. The control effects could reach the maximum in 7~10 days after using the pesticide. They were safe to the crop. The ideal dosage was 300~600mL/hm2, and they were foliage sprayed equably every 15 days.

  2. Mitochondrial DNA COI characterization of Helicoverpa armigera (Lepidoptera: Noctuidae) from Paraguay and Uruguay.

    Science.gov (United States)

    Arnemann, J A; James, W J; Walsh, T K; Guedes, J V C; Smagghe, G; Castiglioni, E; Tay, W T

    2016-04-07

    Since its detection in Brazil in 2013, the Old World cotton bollworm Helicoverpa armigera has been reported in Argentina, Paraguay, and Bolivia. Here we present evidence extending the South American range of H. armigera to Uruguay, using polymerase chain reaction and sequencing of the partial mitochondrial DNA (mtDNA) cytochrome oxidase I region. Molecular characterization of this gene region from individuals from Paraguay also supports previous morphological identification of H. armigera in Paraguay. Shared mtDNA haplotypes in H. armigera from Brazil, Uruguay, and Paraguay were identified. Additional surveying of populations in this region will be imperative to better monitor and understand factors that are underpinning its presence and successful adaptation in these South American regions. We discuss our findings with respect to the development of resistance pest management strategies of this invasive insect pest in a predominantly monoculture soybean crop landscape in the Southern Cone region.

  3. DNA synthesis in the imaginal wing discs of the American bollworm Helicoverpa armigera (Hübner)

    Indian Academy of Sciences (India)

    A Josephrajkumar; B Subrahmanyam

    2002-03-01

    The effect of two insect growth regulators of plant origin viz. plumbagin and azadirachtin and the ecdysteroids 20-hydroxyecdysone, makisterone A and a phytoecdysteroid on DNA synthesis in imaginal wing discs of day 4 final instar Helicoverpa armigera larvae was studied. DNA synthesis increased with increase in time of incubation up to 8 h and decreased later without the addition of moulting hormone. Addition of 20-hydroxyecdysone supported long term acquisition of competence for DNA synthesis in the wing discs. Both DNA synthesis and protein content were drastically reduced in plumbagin and azadirachtin-treated insects. Under in vitro conditions, plumbagin had a more pronounced inhibitory effect than azadirachtin. All the ecdysteroids tested, viz. makisterone A, 20-hydroxyecdysone and the ecdysteroidal fraction from the silver fern Cheilanthes farinosa enhanced DNA synthesis.

  4. Evaluation of advanced chickpea genotypes for resistance to pod borer, helicoverpa armigera (hubner) (lepidoptera: noctuidae)

    International Nuclear Information System (INIS)

    Field studies were conducted to evaluate the comparative varietal resistance in thirteen advanced desi chickpea genotypes against chickpea pod borer (CPB), Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) during 2007-2008. Weekly observations showed that mean larval population of CPB in different genotypes ranged from 0.33 to 4.33 per meter row from first week of March to third week of April, where the pod damage varied from 7.4 to 14.2%. The results manifest that among the tested genotypes, B 8/02, showed the maximum resistant to CPB along with B 8/03, CH 4/02 and CH 9/02 with highest resistant to CPB, less larval population per plant, minimum pod damage and highest grain yield with increase of 256.8 to 285.7% with respect to check. Therefore, conclude that these genotypes can be used in crossing/evolving new elite chickpea varieties. (author)

  5. Effect of 60Co-γ irradiation on mating ability of males of Helicoverpa armigera

    International Nuclear Information System (INIS)

    The effects of γ-rays irradiation on the mating ability and flight capability of male cotton bollworm Helicoverpa armigera were studied in laboratory and field cages. The results showed that when the irradiation dose increased from 0Gy to 400Gy, the flight capability decreased: flight distance decreased from 69.65km to 38.30km; average flight distance decreased from 44.19km to 13.55km. The longevity of the irradiated males was significantly shorter than that of the wilds but there was no significant difference according to different doses. Egg hatchability was affected significantly by irradiation but there was no significant difference in eggs laid per female, fecundation eggs as increasing treated doses. When the ratio of sterilized males (treated dose 200 Gy) to fertile males was as 5:1 in field cages, the F1 hatchability was significantly decreased and the purpose of controlling cotton bollworm population could be effectively achieved. (authors)

  6. Effect of electron beam irradiation on developmental stages of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

    International Nuclear Information System (INIS)

    Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), is an economically important and polyphagous pest, which harms various kinds of food crops and important agricultural plants, such as cotton and paprika. Effects of electron beam irradiation at six dose levels between 50 and 350 Gy on the egg (24–48 h old), the larval (4–5th instar), and the pupal (7-d old for female, 5-d old for male) development, and on the adult (1-d old) reproduction were tested to identify a potential quarantine treatment dose. Increased doses of irradiation on eggs decreased egg hatchability, pupation and adult emergence and increased larval period. ED99 values for inhibition of hatching, pupation and emergence were 460.6, 236.9 and 197.8 Gy, respectively. When larvae were irradiated with more than 280 Gy, no larvae could develop into pupae. ED99 values for inhibition of pupation and adult emergence were 265.6 and 189.6 Gy, respectively. Even though the irradiation on pupa did not completely inhibit adult emergence, most of the pupae emerged to deformed adults. When adults were irradiated, fecundity was not affected. However, F1 egg hatching was completely inhibited at the dose of 350 Gy. ED99 value for inhibition of adult emergence was estimated at 366.5 Gy. Our results suggest that electron beam irradiation could be recommendable as an alternative to MB and as a phytosanitary treatment for quarantine. A treatment dose of less than or equal to 220 Gy is suggested as a potential quarantine treatment to H. armigera egg for prevention of pupation and to larva for prevention of adult emerge. - Highlights: • Electron beam irradiation induced abnormal development of Helicoverpa armigera. • ED99 value for inhibition of adult emergence was estimated at 197.8 Gy for egg. • ED99 value for inhibition of adult emergence was estimated at 189.6 Gy for larva

  7. The olfactory basis for attraction of the Bollworm helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) to host-plant flowers

    OpenAIRE

    Bruce, Toby Johann

    2000-01-01

    The objective of this work was to investigate whether or not olfactory clues play a role in host plant location by the polyphagous moth, Helicoverpa armigera. Volatiles collected from flowers of African marigold, Tagetes erecta, and sweet pea, Lathyrus odouratus, were found to elicit electroantennographic (EAG) responses from the antennae of female H. armigera. Compounds active in GC-EAG analyses of T. erecta floral headspace samples, identified by GC-MS and comparison of retention times on p...

  8. A Toxin-Binding Alkaline Phosphatase Fragment Synergizes Bt Toxin Cry1Ac against Susceptible and Resistant Helicoverpa armigera

    OpenAIRE

    Wenbo Chen; Chenxi Liu; Yutao Xiao; Dandan Zhang; Yongdong Zhang; Xianchun Li; Bruce E Tabashnik; Kongming Wu

    2015-01-01

    Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry) proteins from the bacterium Bacillus thuringiensis (Bt) in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50) of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase p...

  9. Monitoring larval populations of the douglas-fir tussock moth and the western spruce budworm on permanent plots: Sampling methods and statistical properties of data. Forest Service general technical report

    Energy Technology Data Exchange (ETDEWEB)

    Mason, R.R.; Paul, H.G.

    1994-05-01

    Procedures for monitoring Larval populations of the Douglas-fir tussock moth and the western spruce budworm are recommended based on many years experience of sample these species in eastern Oregon and Washington. It is shown that statistically reliable estimates of larval density can be made for a population by sampling host trees in a series of permanent plots in a geographical monitoring unit. The most practical method is to estimate densities of both insect species simultaneously on a plot by the nondestructive sampling of foliage on lower crown branches of host trees. For best results, sampling methods need to be consistent with monitoring done annually to accumulate continuous databases that reflect the behavior of defoliator populations over a long period of time.

  10. Differential Induction of Flavonoids in Groundnut in Response to Helicoverpa armigera and Aphis craccivora Infestation.

    Science.gov (United States)

    War, Abdul Rashid; Sharma, Suraj Prasad; Sharma, Hari Chand

    2016-01-01

    Flavonoids are important plant secondary metabolites, which protect plants from various stresses, including herbivory. Plants differentially respond to insects with different modes of action. High performance liquid chromatography (HPLC) fingerprinting of phenols of groundnut (Arachis hypogaea) plants with differential levels of resistance was carried out in response to Helicoverpa armigera (chewing insect) and Aphis craccivora (sucking pest) infestation. The genotypes used were ICGV 86699, ICGV 86031, ICG 2271 (NCAc 343), ICG 1697 (NCAc 17090), and JL 24. Most of the identified compounds were present in H. armigera- and A. craccivora-infested plants of ICGV 86699. Syringic acid was observed in all the genotypes across the treatments, except in the uninfested control plants of ICG 2271 and aphid-infested plants of ICG 1697. Caffeic acid and umbelliferone were observed only in the H. armigera-infested plants of ICGV 86699. Similarly, dihydroxybenzoic acid and vanillic acid were observed in H. armigera- and aphid-infested plants of ICG 2271 and JL 24, respectively. The peak areas were transformed into the amounts of compounds by using internal standard peak areas and were expressed in nanograms. Quantities of the identified compounds varied across genotypes and treatments. The common compounds observed were chlorogenic, syringic, quercetin, and ferulic acids. These results suggest that depending on the mode of feeding, flavonoids are induced differentially in groundnut plants. PMID:27398031

  11. Cannibalism Affects Core Metabolic Processes in Helicoverpa armigera Larvae-A 2D NMR Metabolomics Study.

    Science.gov (United States)

    Vergara, Fredd; Shino, Amiu; Kikuchi, Jun

    2016-01-01

    Cannibalism is known in many insect species, yet its impact on insect metabolism has not been investigated in detail. This study assessed the effects of cannibalism on the metabolism of fourth-instar larvae of the non-predatory insect Helicoverpa armigera (Lepidotera: Noctuidea). Two groups of larvae were analyzed: one group fed with fourth-instar larvae of H. armigera (cannibal), the other group fed with an artificial plant diet. Water-soluble small organic compounds present in the larvae were analyzed using two-dimensional nuclear magnetic resonance (NMR) and principal component analysis (PCA). Cannibalism negatively affected larval growth. PCA of NMR spectra showed that the metabolic profiles of cannibal and herbivore larvae were statistically different with monomeric sugars, fatty acid- and amino acid-related metabolites as the most variable compounds. Quantitation of ¹H-(13)C HSQC (Heteronuclear Single Quantum Coherence) signals revealed that the concentrations of glucose, glucono-1,5-lactone, glycerol phosphate, glutamine, glycine, leucine, isoleucine, lysine, ornithine, proline, threonine and valine were higher in the herbivore larvae. PMID:27598144

  12. Acute, sublethal, and combination effects of azadirachtin and Bacillus thuringiensis on the cotton bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Abedi, Zahra; Saber, Moosa; Vojoudi, Samad; Mahdavi, Vahid; Parsaeyan, Ehsan

    2014-01-01

    The cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a polyphagous and cosmopolitan insect pest that causes damage to various plants. In this study, the lethal and sublethal effects of azadirachtin and Bacillus thuringiensis Berliner sub sp . kurstaki (Bacillales: Bacillaceae) were evaluated on third instar H. armigera under laboratory conditions. The LC50 values of azadirachtin and Bt were 12.95 and 96.8 µg a.i./mL, respectively. A total mortality of 56.7% was caused on third instar larvae when LC20 values of the insecticides were applied in combination with each other. The LT50 values of azadirachtin and Bt were 4.8 and 3.6 days, respectively. The results of the sublethal study showed that the application of LC30 value of azadirachtin and Bt reduced the larval and pupal weight and increased larval and pupal duration of H. armigera. The longevity and fecundity of female adults were affected significantly by the insecticides. Female fecundity was reduced by the treatments, respectively. The lowest adult emergence ratio and pupation ratio were observed in the azadirachtin treatment. The results indicated that both insecticides have high potential for controlling of the pest. PMID:25373177

  13. Resurgence of the cotton bollworm Helicoverpa armigera in northern Greece associated with insecticide resistance.

    Science.gov (United States)

    Mironidis, George K; Kapantaidaki, Despina; Bentila, Maria; Morou, Evangelia; Savopoulou-Soultani, M; Vontas, John

    2013-08-01

    Helicoverpa armigera has been controlled effectively with chemical insecticides in the major cotton crop production areas of northern Greece for many years. However, a resurgence of the pest was observed in 2010, which significantly affected crop production. During a 4-year survey (2007-2010), we examined the insecticide resistance status of H. armigera populations from two major and representative cotton production areas in northern Greece against seven insecticides (chlorpyrifos, diazinon, methomyl, alpha-cypermethrin, cypermethrin, gamma-cyhalothrin and endosulfan). Full dose-response bioassays on third instar larvae were performed by topical application. Lethal doses at 50% were estimated by probit analysis and resistance factors (RF) were calculated, compared to a susceptible laboratory reference strain. Resistance levels were relatively moderate until 2009, with resistance ratios below 10-fold for organophosphates and carbamates and up to 16-fold for the pyrethroid alpha-cypermethrin. However, resistance rose to 46- and 81-fold for chlorpyrifos and alpha-cypermethrin, respectively in 2010, when the resurgence of the pest was observed. None of the known pyrethroid resistance mutations were found in the pyrethroid-resistant insects. The possible association between resistance and H. armigera resurgence in Greece is discussed.

  14. Return migration of Helicoverpa armigera (Lepidoptera: Noctuidae) during autumn in northern China.

    Science.gov (United States)

    Feng, H-Q; Wu, K-M; Ni, Y-X; Cheng, D-F; Guo, Y-Y

    2005-08-01

    The autumn migration of Helicoverpa armigera (Hübner) was observed with radar and two types of light-trap at Langfang, Hebei province, China in 2001 and 2002. The sudden increase in the proportion of H. armigera moths in the searchlight trap indicated migration into the area and catches increased 10-fold during the second half of the night due to the landing of migrants before dawn. The moths' migratory flights took place at up to 2000 m above the ground, and moths flew differentially at times, and heights, when favourable (i.e. northerly) winds occurred. This facilitated the maximum displacement of moths towards the south during these 'return' migrations. The moths flew over the radar site at consistently high densities through the night, and the resulting flight durations of c. 10 h, at displacement speeds of 30-33 km h-1, would allow moths emerging in the far northeast of China (i.e. Liaoning and Jilin provinces and the Inner Mongolia autonomous region) to migrate into northern China (Hebei, Shandong and Henan provinces). The association of the seasonal migratory movements of H. armigera with crops in northern China is briefly discussed.

  15. Insecticidal potential of defense metabolites from Ocimum kilimandscharicum against Helicoverpa armigera.

    Directory of Open Access Journals (Sweden)

    Priyanka Singh

    Full Text Available Genus Ocimum contains a reservoir of diverse secondary metabolites, which are known for their defense and medicinal value. However, the defense-related metabolites from this genus have not been studied in depth. To gain deeper insight into inducible defense metabolites, we examined the overall biochemical and metabolic changes in Ocimum kilimandscharicum that occurred in response to the feeding of Helicoverpa armigera larvae. Metabolic analysis revealed that the primary and secondary metabolism of local and systemic tissues in O. kilimandscharicum was severely affected following larval infestation. Moreover, levels of specific secondary metabolites like camphor, limonene and β-caryophyllene (known to be involved in defense significantly increased in leaves upon insect attack. Choice assays conducted by exposing H. armigera larvae on O. kilimandscharicum and tomato leaves, demonstrated that O. kilimandscharicum significantly deters larval feeding. Further, when larvae were fed on O. kilimandscharicum leaves, average body weight decreased and mortality of the larvae increased. Larvae fed on artificial diet supplemented with O. kilimandscharicum leaf extract, camphor, limonene and β-caryophyllene showed growth retardation, increased mortality rates and pupal deformities. Digestive enzymes of H. armigera - namely, amylase, protease and lipase- showed variable patterns after feeding on O. kilimandscharicum, which implies striving of the larvae to attain required nutrition for growth, development and metamorphosis. Evidently, selected metabolites from O. kilimandscharicum possess significant insecticidal activity.

  16. Incipient resistance of Helicoverpa punctigera to the Cry2Ab Bt toxin in Bollgard II cotton.

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    Sharon Downes

    Full Text Available Combinations of dissimilar insecticidal proteins ("pyramids" within transgenic plants are predicted to delay the evolution of pest resistance for significantly longer than crops expressing a single transgene. Field-evolved resistance to Bacillus thuringiensis (Bt transgenic crops has been reported for first generation, single-toxin varieties and the Cry1 class of proteins. Our five year data set shows a significant exponential increase in the frequency of alleles conferring Cry2Ab resistance in Australian field populations of Helicoverpa punctigera since the adoption of a second generation, two-toxin Bt cotton expressing this insecticidal protein. Furthermore, the frequency of cry2Ab resistance alleles in populations from cropping areas is 8-fold higher than that found for populations from non-cropping regions. This report of field evolved resistance to a protein in a dual-toxin Bt-crop has precisely fulfilled the intended function of monitoring for resistance; namely, to provide an early warning of increases in frequencies that may lead to potential failures of the transgenic technology. Furthermore, it demonstrates that pyramids are not 'bullet proof' and that rapid evolution to Bt toxins in the Cry2 class is possible.

  17. Influence of CO2 and Temperature on Metabolism and Development of Helicoverpa armigera (Noctuidae: Lepidoptera).

    Science.gov (United States)

    Akbar, S Md; Pavani, T; Nagaraja, T; Sharma, H C

    2016-02-01

    Climate change will have a major bearing on survival and development of insects as a result of increase in CO2 and temperature. Therefore, we studied the direct effects of CO2 and temperature on larval development and metabolism in cotton bollworm, Helicoverpa armigera (Hübner). The larvae were reared under a range of CO2 (350, 550, and 750 ppm) and temperature (15, 25, 35, and 45°C) regimes on artificial diet. Elevated CO2 negatively affected the larval survival, larval weight, larval period, pupation, and adult emergence, but showed a positive effect on pupal weight, pupal period, and fecundity. Increase in temperature exhibited a negative effect on larval survival, larval period, pupal weights, and pupal period, but a positive effect on larval growth. Pupation and adult emergence were optimum at 25°C. Elevated CO2 and temperature increased food consumption and metabolism of larvae by enhancing the activity of midgut proteases, carbohydrases (amylase and cellulase), and mitochondrial enzymes and therefore may cause more damage to crop production. Elevated CO2 and global warming will affect insect growth and development, which will change the interactions between the insect pests and their crop hosts. Therefore, there is need to gain an understanding of these interactions to develop strategies for mitigating the effects of climate change. PMID:26363173

  18. Trichogramma chilotraeae PARASITOID TELUR Helicoverpa armigera (Hubner PADA POPULASI INANG RENDAH

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    - Sujak

    2011-03-01

    Full Text Available Helicoverpa armigera Hubner is an insect pest of corn and cotton crops. Eggs are laid by  H. armigera imago on corn silk and cotton crops often have high mortality, mainly caused by egg parasitoid. H. armigera egg on various agroecosystem reported can  be parasited by at least 12 species of  Trichogrammatidae. The purpose of this study was to determine the diversity of  Trichogrammatidae family as  parasitoid eggs of  H. armigera on  low population. H. armigera egg sample taken from Asembagus, Lamongan and Blora at 1 m2 field  both monoculture and intercropping. Observation of parasitoids and predators  done at the Laboratory of Biological Control Balittas Malang. Parasitoid that appears preserved in the Hoyer medium for identification purposes. low population of  H. armigera Egg in Asembagus is  4 eggs/m2 in both monoculture maize and intercropping with 86-100 days after transplanting (DAT cotton and  4.5 egg/m2 on cotton monoculture and intercropping with 75  DAT soybean, while 2 eggs/m2 in the Lamongan and Blora corn agroecosystem. The dominant egg parasitoid in Asembagus is T. chilotraea, as well as in Lamongan and Blora.

  19. Functional Characteristics of a Novel Chemosensory Protein in the Cotton Bollworm Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tian-tao; WANG Wei-xuan; ZHANG Zi-ding; ZHANG Yong-jun; GUO Yu-yuan

    2013-01-01

    A chemosensory protein named HarmCSP5 in cotton bollworm Helicoverpa armigera (Hübner) was obtained from antennal cDNA libraries and expressed in Escherichia coli. The real time quantitative PCR (RT-qPCR) results indicated that HarmCSP5 gene was mainly expressed in male and female antennae but also expressed in female legs and wings. Competitive binding assays were performed to test the binding affinity of recombinant HarmCSP5 to 60 odor molecules including some cotton volatiles. The resules showed that HarmCSP5 showed strong binding abilities to 4-ehtylbenzaldehyde and 3,4-dimethlbenz aldehyde, whereas methyl phenylacetate, 2-decanone, 1-pentanol, carvenol, isoborneol, nerolidol, 2-nonanone and ethyl heptanoate have relatively weak binding affinity. Moreover, the predicted 3D model of HarmCSP5 consists of sixα-helices located among residues 33-38 (α1), 40-48 (α2), 62-72 (α3), 80-96 (α4), 98-108 (α5), and 116-119 (α6), two pairs of disulfide bridges Cys49-Cys55, Cys75-Cys78. The two amino acid residues, Ile94 and Trp101, may play crucial roles in HarmCSP5 binding with ligands and need further study for confirmation.

  20. Comparative toxicity of mycotoxins to navel orangeworm (Amyelois transitella) and corn earworm (Helicoverpa zea).

    Science.gov (United States)

    Niu, Guodong; Siegel, Joel; Schuler, Mary A; Berenbaum, May R

    2009-08-01

    Mycotoxins, such as aflatoxins and ochratoxins, are widely distributed in nature and are frequently problematic crop contaminants that cause millions of dollars of annual losses in the United States. Insect infestations of crop plants significantly exacerbate mycotoxin contamination. Damage to a variety of nut species by Amyelois transitella Walker (navel orangeworm, NOW) is associated with infection by Aspergillus species and concomitant production of aflatoxins and ochratoxins. Resistance to aflatoxins in this lepidopteran is compared here with the levels of resistance in Helicoverpa zea (corn earworm, CEW), another lepidopteran that routinely encounters aflatoxins in its diet, albeit at lower levels. Measured as the developmental delay caused by aflatoxin B1 (AFB1), it is apparent that the LC(50) (defined as the concentration preventing 50% of newly hatched larvae from entering the 2nd instar within 48 h) for AFB1 is 100 times greater for A. transitella than for H. zea. Similarly, A. transitella 1st instars display substantially higher tolerance to ochratoxin A, another mycotoxin contaminant produced by Aspergillus species, than do H. zea. Our studies indicate that A. transitella, although a hostplant generalist, may well be highly specialized for mycotoxin detoxification.

  1. Bacterial Expression and Kinetic Analysis of Carboxylesterase 001D from Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Yongqiang Li

    2016-04-01

    Full Text Available Carboxylesterasesare an important class of detoxification enzymes involved in insecticide resistance in insects. A subgroup of Helicoverpa armigera esterases, known as Clade 001, was implicated in organophosphate and pyrethroid insecticide resistance due to their overabundance in resistant strains. In this work, a novel carboxylesterasegene 001D of H. armigera from China was cloned, which has an open reading frame of 1665 nucleotides encoding 554 amino acid residues. We used a series of fusion proteins to successfully express carboxylesterase 001D in Escherichia coli. Three different fusion proteins were generated and tested. The enzyme kinetic assay towards 1-naphthyl acetate showed all three purified fusion proteins are active with a Kcat between 0.35 and 2.29 s−1, and a Km between 7.61 and 19.72 μM. The HPLC assay showed all three purified fusion proteins had low but measurable hydrolase activity towards β-cypermethrin and fenvalerate insecticides (specific activities ranging from 0.13 to 0.67 μM·min−1·(μM−1·protein. The enzyme was stable up to 40 °C and at pH 6.0–11.0. The results imply that carboxylesterase 001D is involved in detoxification, and this moderate insecticide hydrolysis may suggest that overexpression of the gene to enhance insecticide sequestration is necessary to allow carboxylesterases to confer resistance to these insecticides in H. armigera.

  2. Insecticidal potential of defense metabolites from Ocimum kilimandscharicum against Helicoverpa armigera.

    Science.gov (United States)

    Singh, Priyanka; Jayaramaiah, Ramesha H; Sarate, Priya; Thulasiram, Hirekodathakallu V; Kulkarni, Mahesh J; Giri, Ashok P

    2014-01-01

    Genus Ocimum contains a reservoir of diverse secondary metabolites, which are known for their defense and medicinal value. However, the defense-related metabolites from this genus have not been studied in depth. To gain deeper insight into inducible defense metabolites, we examined the overall biochemical and metabolic changes in Ocimum kilimandscharicum that occurred in response to the feeding of Helicoverpa armigera larvae. Metabolic analysis revealed that the primary and secondary metabolism of local and systemic tissues in O. kilimandscharicum was severely affected following larval infestation. Moreover, levels of specific secondary metabolites like camphor, limonene and β-caryophyllene (known to be involved in defense) significantly increased in leaves upon insect attack. Choice assays conducted by exposing H. armigera larvae on O. kilimandscharicum and tomato leaves, demonstrated that O. kilimandscharicum significantly deters larval feeding. Further, when larvae were fed on O. kilimandscharicum leaves, average body weight decreased and mortality of the larvae increased. Larvae fed on artificial diet supplemented with O. kilimandscharicum leaf extract, camphor, limonene and β-caryophyllene showed growth retardation, increased mortality rates and pupal deformities. Digestive enzymes of H. armigera - namely, amylase, protease and lipase- showed variable patterns after feeding on O. kilimandscharicum, which implies striving of the larvae to attain required nutrition for growth, development and metamorphosis. Evidently, selected metabolites from O. kilimandscharicum possess significant insecticidal activity. PMID:25098951

  3. BIO-EFFICACY OF INSECTICIDES AGAINST FRUIT BORER (HELICOVERPA ARMIGERA IN TOMATO (LYCOPERSICON ESCULENTUM

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    Ravi Kumar Katroju,

    2014-02-01

    Full Text Available Field experiment carried out during kharif, 2012 at Student’s Farm, College of Agriculture, Rajendranagar, Hyderabad to evaluate the efficacy of insecticides viz., emamectin benzoate 5 SG @11 g a.i. ha-1, emamectin benzoate 5 SG @ 22 g a.i. ha-1, profenophos 50 EC @ 500 g a.i. ha-1, profenophos 50 EC @1000 g a.i. ha-1, spinosad 45 SC @ 100 g a.i. ha-1, bifenthrin 10 EC @ 100 g a.i. ha-1 and Bacillus thuringiensis @ 25 g a.i. ha-1against tomato fruit borer (Helicoverpa armigera. Among all the insecticides, profenophos (1000 g a.i. ha-1 was found to be the most effective one with a maximum reduction in fruit borer population (65.20%, minimum per cent of fruit damage (28.80% and maximum yield (26.43 kg/20 m2 followed by bifenthrin @ 100 g a.i.ha-1 with reduced larval population of 64.51% and damaged fruits 32.60%.

  4. Identification, isolation and characterization of the antifeedant constituent of Clausena anisata against Helicoverpa armigera (Lepidoptera: Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    Olufemi O.R.Pitan; O.O.Ayelaagbe; Hong-Lei Wang; Chen-Zhu Wang

    2009-01-01

    Hexane, petroleum ether, chloroform, ethyl acetate, methanol and water extracts of Clausena anisata [(Willd.) Hook F. Ex Benth] leaves and roots were evaluated against Helicoverpa armigera (Hubner) for antifeedant activities. Antifeedant activity was confirmed, and was found to be higher in root extracts than those of the leaf. Chloroform and petroleum ether extracts of the root showed strongest antifeedant activities (DC50S [concentration (C) causing 50% deterrence compared with the control] 0.014% and 0.016% respectively), and root extracts were fractionated using silica gel column chromatography. One fraction of the chloroform and one of the petroleum ether root extracts was active; and on the basis of mass spectroscopy and 1H and 13C nuclear magnetic resonance spectral data, the active compounds in the two fractious were confirmed to be identical, and identified as osthol [2H-I-Benzopyran-2-one, 7-methoxy-8-(3-methyl-2-butenyl)]. The highest concentratiun of osthol was found in the chloroform root extract. Antifeedant activities of the root extracts, as measured by DC50 values, were highly correlated with their osthol contents. Approximately 99% of the variation in bioactivity of the root extracts could be accounted for by variation in osthol content; osthol therefore, appeared to be an antifeedant component of C. Anisata to H. Armigera. This may provide a new approach to managing this pest.

  5. Bacterial Expression and Kinetic Analysis of Carboxylesterase 001D from Helicoverpa armigera.

    Science.gov (United States)

    Li, Yongqiang; Liu, Jianwei; Lu, Mei; Ma, Zhiqing; Cai, Chongling; Wang, Yonghong; Zhang, Xing

    2016-01-01

    Carboxylesterasesare an important class of detoxification enzymes involved in insecticide resistance in insects. A subgroup of Helicoverpa armigera esterases, known as Clade 001, was implicated in organophosphate and pyrethroid insecticide resistance due to their overabundance in resistant strains. In this work, a novel carboxylesterasegene 001D of H. armigera from China was cloned, which has an open reading frame of 1665 nucleotides encoding 554 amino acid residues. We used a series of fusion proteins to successfully express carboxylesterase 001D in Escherichia coli. Three different fusion proteins were generated and tested. The enzyme kinetic assay towards 1-naphthyl acetate showed all three purified fusion proteins are active with a Kcat between 0.35 and 2.29 s(-1), and a Km between 7.61 and 19.72 μM. The HPLC assay showed all three purified fusion proteins had low but measurable hydrolase activity towards β-cypermethrin and fenvalerate insecticides (specific activities ranging from 0.13 to 0.67 μM·min(-1)·(μM(-1)·protein)). The enzyme was stable up to 40 °C and at pH 6.0-11.0. The results imply that carboxylesterase 001D is involved in detoxification, and this moderate insecticide hydrolysis may suggest that overexpression of the gene to enhance insecticide sequestration is necessary to allow carboxylesterases to confer resistance to these insecticides in H. armigera. PMID:27049381

  6. Alterations in the Helicoverpa armigera midgut digestive physiology after ingestion of pigeon pea inducible leucine aminopeptidase.

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    Purushottam R Lomate

    Full Text Available Jasmonate inducible plant leucine aminopeptidase (LAP is proposed to serve as direct defense in the insect midgut. However, exact functions of inducible plant LAPs in the insect midgut remain to be estimated. In the present investigation, we report the direct defensive role of pigeon pea inducible LAP in the midgut of Helicoverpa armigera (Lepidoptera: Noctuidae and responses of midgut soluble aminopeptidases and serine proteinases upon LAP ingestion. Larval growth and survival was significantly reduced on the diets supplemented with pigeon pea LAP. Aminopeptidase activities in larvae remain unaltered in presence or absence of inducible LAP in the diet. On the contrary, serine proteinase activities were significantly decreased in the larvae reared on pigeon pea LAP containing diet as compared to larvae fed on diet without LAP. Our data suggest that pigeon pea inducible LAP is responsible for the degradation of midgut serine proteinases upon ingestion. Reduction in the aminopeptidase activity with LpNA in the H. armigera larvae was compensated with an induction of aminopeptidase activity with ApNA. Our findings could be helpful to further dissect the roles of plant inducible LAPs in the direct plant defense against herbivory.

  7. Evolution of Resistance by Helicoverpa zea (Lepidoptera: Noctuidae) Infesting Insecticidal Crops in the Southern United States.

    Science.gov (United States)

    Pan, Zaiqi; Onstad, David; Crain, Philip; Crespo, Andre; Hutchison, William; Buntin, David; Porter, Pat; Catchot, Angus; Cook, Don; Pilcher, Clint; Flexner, Lindsey; Higgins, Laura

    2016-04-01

    We created a deterministic, frequency-based model of the evolution of resistance by corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), to insecticidal traits expressed in crops planted in the heterogeneous landscapes of the southern United States. The model accounts for four generations of selection by insecticidal traits each year. We used the model results to investigate the influence of three factors on insect resistance management (IRM): 1) how does adding a third insecticidal trait to both corn and cotton affect durability of the products, 2) how does unstructured corn refuge influence IRM, and 3) how do block refuges (50% compliance) and blended refuges compare with regard to IRM? When Bt cotton expresses the same number of insecticidal traits, Bt corn with three insecticidal traits provides longer durability than Bt corn with two pyramided traits. Blended refuge provides similar durability for corn products compared with the same level of required block refuge when the rate of refuge compliance by farmers is 50%. Results for Mississippi and Texas are similar, but durabilities for corn traits are surprisingly lower in Georgia, where unstructured corn refuge is the highest of the three states, but refuge for Bt cotton is the lowest of the three states. Thus, unstructured corn refuge can be valuable for IRM but its influence is determined by selection for resistance by Bt cotton. PMID:26637533

  8. Differential Induction of Flavonoids in Groundnut in Response to Helicoverpa armigera and Aphis craccivora Infestation

    Science.gov (United States)

    War, Abdul Rashid; Sharma, Suraj Prasad; Sharma, Hari Chand

    2016-01-01

    Flavonoids are important plant secondary metabolites, which protect plants from various stresses, including herbivory. Plants differentially respond to insects with different modes of action. High performance liquid chromatography (HPLC) fingerprinting of phenols of groundnut (Arachis hypogaea) plants with differential levels of resistance was carried out in response to Helicoverpa armigera (chewing insect) and Aphis craccivora (sucking pest) infestation. The genotypes used were ICGV 86699, ICGV 86031, ICG 2271 (NCAc 343), ICG 1697 (NCAc 17090), and JL 24. Most of the identified compounds were present in H. armigera- and A. craccivora-infested plants of ICGV 86699. Syringic acid was observed in all the genotypes across the treatments, except in the uninfested control plants of ICG 2271 and aphid-infested plants of ICG 1697. Caffeic acid and umbelliferone were observed only in the H. armigera-infested plants of ICGV 86699. Similarly, dihydroxybenzoic acid and vanillic acid were observed in H. armigera- and aphid-infested plants of ICG 2271 and JL 24, respectively. The peak areas were transformed into the amounts of compounds by using internal standard peak areas and were expressed in nanograms. Quantities of the identified compounds varied across genotypes and treatments. The common compounds observed were chlorogenic, syringic, quercetin, and ferulic acids. These results suggest that depending on the mode of feeding, flavonoids are induced differentially in groundnut plants. PMID:27398031

  9. Expression of Cry1Aa in cassava improves its insect resistance against Helicoverpa armigera.

    Science.gov (United States)

    Duan, Xiaoguang; Xu, Jia; Ling, Erjun; Zhang, Peng

    2013-09-01

    Lepidopteran insects affect cassava production globally, especially in intercropping system. The expression of Cry toxins in transgenic crops has contributed to an efficient control of insect pests, leading to a significant reduction in chemical insecticide usage. Helicoverpa armigera is a Lepidopteran pest that feeds on a wide range of plants like cotton and cassava. In the present study, transgenic cassava plants over-expressing Cry1Aa, which we named as Bt cassava, were developed and used to evaluate its efficacy against H. armigera as a model. Insect feeding assays were carried out to test the effects of Bt cassava leaves on the development and survival of H. armigera. Significant reduction (P cassava leaves in comparison with those fed with wild-type cassava leaves. The higher expression of Cry1Aa in transgenic cassava caused the lethal effect in larvae, in contrast to the normal growth and development of adults and pupation observed when fed with wild-type leaves. Morphological observation on the larval midguts showed that the consumption of Bt cassava affected the gut integrity of H. armigera. The columnar cells of the midgut epithelium were dramatically damaged and showed loose or disordered structure. Their cytoplasms become highly vacuolated and contained disorganized microvilli. Our study demonstrated that the transgenic cassava expressing the Cry1Aa is effective in controlling H. armigera. Our Bt transgenic cassava plant would provide a long-term beneficial effect on all crops in intercropping system, which in-turn, will be profitable to the farmers.

  10. A brave new world for an old world pest: Helicoverpa armigera (Lepidoptera: Noctuidae) in Brazil.

    Science.gov (United States)

    Tay, Wee Tek; Soria, Miguel F; Walsh, Thomas; Thomazoni, Danielle; Silvie, Pierre; Behere, Gajanan T; Anderson, Craig; Downes, Sharon

    2013-01-01

    The highly polyphagous Old World cotton bollworm Helicoverpa armigera is a quarantine agricultural pest for the American continents. Historically H. armigera is thought to have colonised the American continents around 1.5 to 2 million years ago, leading to the current H. zea populations on the American continents. The relatively recent species divergence history is evident in mating compatibility between H. zea and H. armigera under laboratory conditions. Despite periodic interceptions of H. armigera into North America, this pest species is not believed to have successfully established significant populations on either continent. In this study, we provide molecular evidence via mitochondrial DNA (mtDNA) cytochrome oxidase I (COI) and cytochrome b (Cyt b) partial gene sequences for the successful recent incursion of H. armigera into the New World, with individuals being detected at two sites (Primavera do Leste, Pedra Preta) within the State of Mato Grosso in Brazil. The mtDNA COI and Cyt b haplotypes detected in the Brazilian H. armigera individuals are common throughout the Old World, thus precluding identification of the founder populations. Combining the two partial mtDNA gene sequences showed that at least two matrilines are present in Brazil, while the inclusion of three nuclear DNA Exon-Primed Intron-Crossing (EPIC) markers identified a further two possible matrilines in our samples. The economic, biosecurity, resistance management, ecological and evolutionary implications of this incursion are discussed in relation to the current agricultural practices in the Americas.

  11. A brave new world for an old world pest: Helicoverpa armigera (Lepidoptera: Noctuidae in Brazil.

    Directory of Open Access Journals (Sweden)

    Wee Tek Tay

    Full Text Available The highly polyphagous Old World cotton bollworm Helicoverpa armigera is a quarantine agricultural pest for the American continents. Historically H. armigera is thought to have colonised the American continents around 1.5 to 2 million years ago, leading to the current H. zea populations on the American continents. The relatively recent species divergence history is evident in mating compatibility between H. zea and H. armigera under laboratory conditions. Despite periodic interceptions of H. armigera into North America, this pest species is not believed to have successfully established significant populations on either continent. In this study, we provide molecular evidence via mitochondrial DNA (mtDNA cytochrome oxidase I (COI and cytochrome b (Cyt b partial gene sequences for the successful recent incursion of H. armigera into the New World, with individuals being detected at two sites (Primavera do Leste, Pedra Preta within the State of Mato Grosso in Brazil. The mtDNA COI and Cyt b haplotypes detected in the Brazilian H. armigera individuals are common throughout the Old World, thus precluding identification of the founder populations. Combining the two partial mtDNA gene sequences showed that at least two matrilines are present in Brazil, while the inclusion of three nuclear DNA Exon-Primed Intron-Crossing (EPIC markers identified a further two possible matrilines in our samples. The economic, biosecurity, resistance management, ecological and evolutionary implications of this incursion are discussed in relation to the current agricultural practices in the Americas.

  12. Functional specificity of sex pheromone receptors in the cotton bollworm Helicoverpa armigera.

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    Yang Liu

    Full Text Available Male moths can accurately perceive the sex pheromone emitted from conspecific females by their highly accurate and specific olfactory sensory system. Pheromone receptors are of special importance in moth pheromone reception because of their central role in chemosensory signal transduction processes that occur in olfactory receptor neurons in the male antennae. There are a number of pheromone receptor genes have been cloned, however, only a few have been functionally characterized. Here we cloned six full-length pheromone receptor genes from Helicoverpa armigera male antennae. Real-time PCR showing all genes exhibited male-biased expression in adult antennae. Functional analyses of the six pheromone receptor genes were then conducted in the heterologous expression system of Xenopus oocytes. HarmOR13 was found to be a specific receptor for the major sex pheromone component Z11-16:Ald. HarmOR6 was equally tuned to both of Z9-16: Ald and Z9-14: Ald. HarmOR16 was sensitively tuned to Z11-16: OH. HarmOR11, HarmOR14 and HarmOR15 failed to respond to the tested candidate pheromone compounds. Our experiments elucidated the functions of some pheromone receptor genes of H. armigera. These advances may provide remarkable evidence for intraspecific mating choice and speciation extension in moths at molecular level.

  13. Momordica charantia trypsin inhibitor Ⅱ inhibits growth and development of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    Manasi Alok Telang; Prashant Pyati; Mohini Sainani; Vidya Shrikant Gupta; Ashok Prabhakar Giri

    2009-01-01

    Bitter gourd (Momordica charantia L.) seeds contain several squash-type serine proteinase inhibitors (PIs),which inhibit the digestive proteinases of the polyphagous insect pest Helicoverpa armigera.In the present work isolation of a DNA sequence encoding the mature peptide of a trypsin inhibitor McTI-Ⅱ,its cloning and expression as a recombinant protein using Pichia pastoris have been reported.Recombinant McTI-Ⅱinhibited bovine trypsin at 1:1 molar ratio,as expected,but did not inhibit chymotrypsin or elastase.McTI-Ⅱalso strongly inhibited trypsin-like proteinases (81% inhibition) as well as the total proteolytic activity of digestive proteinases (70% inhibition) from the midgut of H.armigera larvae.The insect larvae fed with McTI-Ⅱ-incorporated artificial diet suffered over 70% reduction in the average larval weight after 12 days of feeding.Moreover,ingestion of McTI-Ⅱresulted in 23% mortality in the larval population.The strong antimetabolic activity of McTI-Ⅱtoward H.armigera indicates its probable use in developing insect tolerance in susceptible plants.

  14. SEASONAL INCIDENCE OF TOBACCO CAPSULE BORER, HELICOVERPA ARMIGERA (HUBNER) HARDWICK ON BIDI TOBACCO (SEED CROP) IN MIDDLE GUJARAT

    OpenAIRE

    C. G. SOLANKI, C. B. DHOBI*, M. V. PATEL D. M. MEHTA

    2014-01-01

    ABSTRACT: A field experiment was conducted to study the seasonal incidence of tobacco capsule borer, Helicoverpa armigera (Hubner) Hardwick on tobacco (seed crop) during rabi  2011-12. Peak incidence of H. armigera eggs was recorded during December second fortnight and incidence of larvae was peak during January first fortnight. During cropping period H. armigera egg load ranged from 0.14 to 1.80 eggs per plant whereas, larvae ranged from 0.18 to 0.52 larvae per plant. Temperature, vapor ...

  15. Structural organization of the Helicoverpa zea gene encoding the precursor protein for pheromone biosynthesis-activating neuropeptide and other neuropeptides.

    OpenAIRE

    Ma, P W; Knipple, D C; Roelofs, W.L.

    1994-01-01

    Sex pheromone biosynthesis in a number of moth species is induced by a conserved 33-amino acid amidated neuropeptide PBAN (pheromone biosynthesis-activating neuropeptide). We have isolated and characterized the Helicoverpa zea PBAN cDNA corresponding to a 766-nucleotide mRNA that is expressed in the subesophageal ganglion of adult moths. This mRNA is encoded on a transcription unit comprising 6 exons. The longest open reading frame of the cDNA encodes a 194-amino acid precursor protein that c...

  16. Tarsal taste neuron activity and proboscis extension reflex in response to sugars and amino acids in Helicoverpa armigera (Hübner)

    NARCIS (Netherlands)

    Zhang, Y.F.; Loon, van J.J.A.; Wang, C.Z.

    2010-01-01

    In adult female Helicoverpa armigera (Hübner), the fifth tarsomere of the prothoracic legs bears 14 gustatory trichoid chemosensilla. These chemosensilla were characterized through electrophysiological experiments by stimulating with sucrose, glucose, fructose, maltose, myo-inositol and 20 common am

  17. Estimation of long-terminal repeat element content in the Helicoverpa zea genome from next generation sequencing of reduced representation bacterial artificial chromosome (BAC) pools

    Science.gov (United States)

    The lepidopteran pest insect, Helicoverpa zea, feeds on cultivated corn and cotton crops in North America where control remains challenging due to evolution of resistance to chemical and transgenic insecticidal toxins, yet few genomic resources are available for this species. A bacterial artificial...

  18. Life table and consumption capacity of corn earworm, Helicoverpa armigera, fed asparagus, Asparagus officinalis.

    Science.gov (United States)

    Jha, Ratna Kumar; Tuan, Shu-Jen; Chi, Hsin; Tang, Li-Cheng

    2014-03-01

    The life table and consumption rate of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) reared on asparagus, Asparagus officinalis L. (Asparagales: Asparagaceae) were studied under laboratory conditions to assess their interaction. Development, survival, fecundity, and consumption data were analyzed by the age-stage, twosex life table. This study indicated that asparagus is a natural host of H. armigera. However, the poor nutritional content in asparagus foliage and the poor fitness of H. armigera that fed on asparagus indicated that asparagus is a suboptimal host in comparison to hybrid sweet corn. The uncertainty associated with life table parameters was estimated by using jackknife and bootstrap techniques, and the results were compared for statistical inference. The intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and mean generation time (T) were estimated by the jackknife technique to be 0.0780 day(-1), 1.0811 day(-1), 67.4 offspring, and 54.8 days, respectively, while those estimated by the bootstrap technique were 0.0752 day(-1), 1.0781 day(-1), 68.0 offspring, and 55.3 days, respectively. The net consumption rate of H. armigera, as estimated by the jackknife and bootstrap technique, was 1183.02 and 1132.9 mg per individual, respectively. The frequency distribution of sample means obtained by the jackknife technique failed the normality test, while the bootstrap results fit the normal distribution well. By contrast, the relationship between the mean fecundity and the net reproductive rate, as estimated by the bootstrap technique, was slightly inconsistent with the relationship found by mathematical proof. The application of the jackknife and bootstrap techniques in estimating population parameters requires further examination.

  19. Efifciency of Different Methods for dsRNA Delivery in Cotton Bollworm (Helicoverpa armigera)

    Institute of Scientific and Technical Information of China (English)

    YANG Jing; HAN Zhao-jun

    2014-01-01

    RNAi trigged by dsRNA not only facilitates the development of molecular biology, but also initiates a new way for pest control by silence of fatal genes. However, one of the key limitations in pest control is lack of the convenient and efifcient method for dsRNA delivery. In this study, different dsRNA delivery methods at their own optimum conditions were evaluated comparatively for their efifciency with Helicoverpa armigera as test animal. It was found that the popular one-time injection of larvae with dsRNA could reduce the pupation rate by 43.0%and enhance larva mortality by 11.7%. One-time ingestion of dsRNA did not result in any signiifcant effect on phenotype. Continuous ingestion of in vitro synthesized dsRNA by refreshing the bait diet every day caused 40.4% decrease in successful pupation and 10.0% increase in larval mortality, which was similar as one-time injection. The most efifcient method was found to be the continuous ingestion of the bacteria containing dsRNA expressed, which reduced the rate of pupation by 68.7%and enhanced the larval mortality by 34.1%. Further analysis found that dsRNA was degraded faster in midgut juice than in hemolymph. However, the cell of bacteria could protect dsRNA and delay the degradation in the midgut juice of H. armigera. These results throw light on the application of dsRNA in pest management with proper ways.

  20. Integration of inherited sterility and other pest management strategies for Helicoverpa zea: Status and potential

    International Nuclear Information System (INIS)

    The corn earworm, Helicoverpa zea (Boddie), is one of the most destructive pests of field crops in the United States of America. Currently, control of H. zea is achieved almost entirely through the use of synthetic insecticides. However, successful application of the inherited sterility principle to a wild population of H. zea during a pilot test has encouraged further development of this pest control strategy. Data from recent studies and population models suggest that the full potential of inherited sterility as an area wide control strategy for H. zea and other lepidopteran pests may be realized only when inherited sterility is integrated with other suppression methods. Applications of singular, non-insecticidal methods for area wide suppression of H. zea have had limited success and have been vulnerable to temporary programme failures (e.g. inclement weather, reduced insect rearing output, etc.). An integrated approach would be horizontally diversified through the use of several strategies which use different modes of action and, therefore, would be less vulnerable to temporary programme failures than would a single strategy. Combining two or more control strategies with additive effects may increase programme efficiency. However, the greatest benefit in combining inherited sterility with other control strategies is the dynamic synergistic effects. The demonstrated potential of inherited sterility to reduce the reproductive ability of H. zea and the demonstrated capacity of inherited sterility to perform compatibly and synergistically with other control strategies suggest that inherited sterility should be major component of future integrated approaches to managing H. zea. (author). 13 refs, 2 figs

  1. Life table and consumption capacity of corn earworm, Helicoverpa armigera, fed asparagus, Asparagus officinalis.

    Science.gov (United States)

    Jha, Ratna Kumar; Tuan, Shu-Jen; Chi, Hsin; Tang, Li-Cheng

    2014-01-01

    The life table and consumption rate of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) reared on asparagus, Asparagus officinalis L. (Asparagales: Asparagaceae) were studied under laboratory conditions to assess their interaction. Development, survival, fecundity, and consumption data were analyzed by the age-stage, twosex life table. This study indicated that asparagus is a natural host of H. armigera. However, the poor nutritional content in asparagus foliage and the poor fitness of H. armigera that fed on asparagus indicated that asparagus is a suboptimal host in comparison to hybrid sweet corn. The uncertainty associated with life table parameters was estimated by using jackknife and bootstrap techniques, and the results were compared for statistical inference. The intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and mean generation time (T) were estimated by the jackknife technique to be 0.0780 day(-1), 1.0811 day(-1), 67.4 offspring, and 54.8 days, respectively, while those estimated by the bootstrap technique were 0.0752 day(-1), 1.0781 day(-1), 68.0 offspring, and 55.3 days, respectively. The net consumption rate of H. armigera, as estimated by the jackknife and bootstrap technique, was 1183.02 and 1132.9 mg per individual, respectively. The frequency distribution of sample means obtained by the jackknife technique failed the normality test, while the bootstrap results fit the normal distribution well. By contrast, the relationship between the mean fecundity and the net reproductive rate, as estimated by the bootstrap technique, was slightly inconsistent with the relationship found by mathematical proof. The application of the jackknife and bootstrap techniques in estimating population parameters requires further examination. PMID:25373181

  2. Influences of insecticides on toxicity and cuticular penetration of abamectin in Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    QIANGWANG; JIA-ANCHENG; ZHONG-MINLIU; SHENG-GANWU; XUE-PINGZHAO; CHANG-XINGWU

    2005-01-01

    Synergistic actions for mixtures of abamectin with other insecticides in some insect pests were evaluated, and the possible synergistic mechanism was studied by the comparison in toxicity and cuticular penetration of abamectin between with and without other insecticides or synergists in Helicoverpa armigera larvae. The results of bioassay showed that horticultural mineral oil (HMO), hexaflumuron, chlorpyrifos, and some other insecticides were synergistic to abamectin with 152.0-420.0 of co-toxicity coefficient(CTC) in some agricultural insect pests. In topical application tests, HMO or piperonyl butoxide (PBO) increased the toxicity of abamectin in larvae of H. armigera, but the mortality was not affected by s,s,s-tributylphorotrithioate (DEF) and triphenylphosphate (TPP). The synergistic action of HMO was obviously higher than PBO, and when treated simultaneously with abamectin, HMO gave a more significant synergism than if treated 2 hours ahead. The highest synergistic effect (SE) was found in the mixture of ‘abamectin+HMO (1:206)'. The mortality did not increase or the toxicity drop, when a synergist or HMO was added into the mixture of ‘abamectin+HMO' or ‘abamectin+synergist', respectively. Results from the isotope tracing experiments showed that HMO significantly enhanced the penetration of 3H-abamectin through the cuticle of H.armigera larvae, which resulted in the synergism of the mixture. The cuticular penetration of 3H-abamectin was not accumulatively affected by chlorpyrifos, nor by hexaflumuron,though there was an inhibition within 30 seconds or 1 hour after treated by these two chemicals respectively. Results suggested that the synergism of abamectin mixed with hexaflumuron or chlorpyrifos might be related to inhibition of metabolic enzymes or target sites in the larvae.

  3. Effect of electron beam irradiation on developmental stages of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Kim, Junheon; Chung, Soon-Oh; Jang, Sin Ae; Jang, Miyeon; Park, Chung Gyoo

    2015-07-01

    Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), is an economically important and polyphagous pest, which harms various kinds of food crops and important agricultural plants, such as cotton and paprika. Effects of electron beam irradiation at six dose levels between 50 and 350 Gy on the egg (24-48 h old), the larval (4-5th instar), and the pupal (7-d old for female, 5-d old for male) development, and on the adult (1-d old) reproduction were tested to identify a potential quarantine treatment dose. Increased doses of irradiation on eggs decreased egg hatchability, pupation and adult emergence and increased larval period. ED99 values for inhibition of hatching, pupation and emergence were 460.6, 236.9 and 197.8 Gy, respectively. When larvae were irradiated with more than 280 Gy, no larvae could develop into pupae. ED99 values for inhibition of pupation and adult emergence were 265.6 and 189.6 Gy, respectively. Even though the irradiation on pupa did not completely inhibit adult emergence, most of the pupae emerged to deformed adults. When adults were irradiated, fecundity was not affected. However, F1 egg hatching was completely inhibited at the dose of 350 Gy. ED99 value for inhibition of adult emergence was estimated at 366.5 Gy. Our results suggest that electron beam irradiation could be recommendable as an alternative to MB and as a phytosanitary treatment for quarantine. A treatment dose of less than or equal to 220 Gy is suggested as a potential quarantine treatment to H. armigera egg for prevention of pupation and to larva for prevention of adult emerge.

  4. Revisiting macronutrient regulation in the polyphagous herbivore Helicoverpa zea (Lepidoptera: Noctuidae): New insights via nutritional geometry.

    Science.gov (United States)

    Deans, Carrie A; Sword, Gregory A; Behmer, Spencer T

    2015-10-01

    Insect herbivores that ingest protein and carbohydrates in physiologically-optimal proportions and concentrations show superior performance and fitness. The first-ever study of protein-carbohydrate regulation in an insect herbivore was performed using the polyphagous agricultural pest Helicoverpa zea. In that study, experimental final instar caterpillars were presented two diets - one containing protein but no carbohydrates, the other containing carbohydrates but no protein - and allowed to self-select their protein-carbohydrate intake. The results showed that H. zea selected a diet with a protein-to-carbohydrate (p:c) ratio of 4:1. At about this same time, the geometric framework (GF) for the study of nutrition was introduced. The GF is now established as the most rigorous means to study nutrient regulation (in any animal). It has been used to study protein-carbohydrate regulation in several lepidopteran species, which exhibit a range of self-selected p:c ratios between 0.8 and 1.5. Given the economic importance of H. zea, and it is extremely protein-biased p:c ratio of 4:1 relative to those reported for other lepidopterans, we decided to revisit its protein-carbohydrate regulation. Our results, using the experimental approach of the GF, show that H. zea larvae self-select a p:c ratio of 1.6:1. This p:c ratio strongly matches that of its close relative, Heliothis virescens, and is more consistent with self-selected p:c ratios reported for other lepidopterans. Having accurate protein and carbohydrate regulation information for an insect herbivore pest such as H. zea is valuable for two reasons. First, it can be used to better understand feeding patterns in the field, which might lead to enhanced management. Second, it will allow researchers to develop rearing diets that more accurately reflect larval nutritional needs, which has important implications for resistance bioassays and other measures of physiological stress. PMID:26141409

  5. Biology, Ecology, and Evolving Management of Helicoverpa zea (Lepidoptera: Noctuidae) in Sweet Corn in the United States.

    Science.gov (United States)

    Olmstead, Daniel L; Nault, Brian A; Shelton, Anthony M

    2016-08-01

    The corn earworm, Helicoverpa zea (Boddie), is a polyphagous pest found throughout the United States, where it attacks many field and vegetable crops. Although H. zea has long been a traditional pest of sweet corn, its importance to this crop has increased dramatically over the past two decades. In this review, we summarize information critical for current and future management of H. zea in sweet corn production in the United States. First, we discuss the pest status of H. zea and its life history, including migration, infestation and larval development, diapause, overwintering, and abiotic factors that affect its biology. Next we describe monitoring methods, crop protection decision-making processes, chemical control options, and the use of genetic technologies for control of H. zea Alternative H. zea management options including biological control, cultural controls, host plant resistance, and pheromone disruption are also reviewed. The role of climate change and its effects on H. zea and its ecology are discussed, as well as the recent invasion of its relative, Helicoverpa armigera (Hübner), which is a major pest of corn in other parts of the world. To conclude, we suggest future research opportunities for H. zea and H. armigera management in sweet corn. PMID:27329622

  6. Cross-resistance to alpha-cypermethrin after xanthotoxin ingestion in Helicoverpa zea (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Li, X; Zangerl, A R; Schuler, M A; Berenbaum, M R

    2000-02-01

    Cytochrome P450 monooxygenases (P450) are membrane-bound hemoproteins that play important roles in conferring protection against both naturally occurring phytochemicals and synthetic organic insecticides. Despite the potential for common modes of detoxification, cross-resistance between phytochemicals and synthetic organic insecticides has rarely been documented. In this study, we examined the responses of a susceptible strain of corn earworm, Helicoverpa zea (Boddie), a polyphagous noctuid, to exposure by an allelochemical infrequently encountered in its host plants and by an insecticide widely used for control purposes. Within a single generation, survivors of xanthotoxin exposure displayed higher levels of tolerance to alpha-cypermethrin than did unexposed control larvae. The F1 offspring of xanthotoxin-exposed survivors also displayed higher alpha-cypermethrin tolerance than did offspring of unexposed control larvae, suggesting that increased alpha-cypermethrin tolerance after xanthotoxin exposure represents, at least in part, heritable resistance. Administration of piperonyl butoxide, a P450 synergist, demonstrated that resistance to both xanthotoxin and alpha-cypermethrin is P450-mediated. Alpha-cypermethrin-exposed survivors, however, failed to show superior growth on xanthotoxin diets. Assays with control larvae, larvae induced by both xanthotoxin and alpha-cypermethrin, and survivors of LD50 doses of both compounds indicated that H. zea midgut P450s are capable of metabolizing both xanthotoxin and alpha-cypermethrin. Metabolism of each compound is significantly inhibited by the presence of the other compound, suggesting that at least one form of P450 in H. zea midguts degrades both compounds and may constitute the biochemical basis for possible cross-resistance. Compared with control larvae, xanthotoxin- and alpha-cypermethrin-induced larvae displayed 2- to 4-fold higher P450-mediated metabolism of both compounds. However, xanthotoxin- and alpha

  7. Determination of lethal concentration (LC50 for different insecticides against third instar larvae of Helicoverpa armigera (Hubner (LEPIDOPTERA:NOCTUIDAE

    Directory of Open Access Journals (Sweden)

    M. Hamed

    2006-03-01

    Full Text Available The efficacy of LorsbanTM, Alpha-cypermethrinTM and KarateTM was assessed by larval dip bioassay against third instar larvae of American bollworm, Helicoverpa armigera (Hub. collected from a cotton field at Faisalabad and reared in the laboratory until F1 generation. Third instar larvae were used to assess the toxicity of insecticides after 48 hrs of insecticide treatments. Results showed that toxicity of Karate was above all with LC50 of 71.31ppm followed by Alpha-cypermethrin with LC50 287.87 and Lorsban 464.85, respectively. These results showed the increased resistance of H. armigera against Lorsban in F1 generation under laboratory conditions.

  8. Insecticidal activity of venomous saliva from Rhynocoris fuscipes (Reduviidae against Spodoptera litura and Helicoverpa armigera by microinjection and oral administration

    Directory of Open Access Journals (Sweden)

    K Sahayaraj

    2011-01-01

    Full Text Available Rhynocoris fuscipes is a potential predator of many economically important pests in India. In the present study, its venomous saliva (VS was collected by milking and diluted with HPLC grade water to different concentrations (200, 400, 600, 800 and 1000 ppm. Microinjection of Rhynocoris fuscipes VS was more toxic than its oral administration in Helicoverpa armigera (cotton bollworm and Spodoptera litura (tobacco cutworm. Thus, R. fuscipes VS was found to be toxic to third instar S. litura and H. armigera with respective LD50s of 846.35 and 861.60 ppm/larva at 96 hours after microinjection. The current results showed that VS of Rhynocoris fuscipes caused mortality of H. armigera and S. litura. Active peptides from VS may be isolated, identified and assessed for their impact in order to ascertain how they alter the physiology of these pests, information that could be applicable in pest management programs.

  9. Bioactivity of Pseudocalymma alliaceum (Lam.) Sandwith (Bignoniaceae) against Spodoptera litura Fabricius and Helicoverpa armigera Hübner (Lepidotera:Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    Alagarmalai Jeyasankar; Tamilarasu Chinnamani

    2014-01-01

    Objective: To evaluate the antifeedant, larvicidal and insect growth inhibitory activities of crude extracts of Pseudocalymma alliaceum tested against fourth instar larvae of Spodoptera litura (S. litura) and Helicoverpa armigera (H. armigera). Methods: Hexane, chloroform and ethyl acetate extracts were prepared and tested for antifeedant, insecticidal and growth inhibitory activities against fourth instar larvae of S. litura and H. armigera.Results:Ethyl acetate extract showed promising antifeedant, insecticidal activity against S. litura and H. armigera. Maximum percentage of deformed larvae, pupae and adults were found on treatment with ethyl acetate extract. Percentage of successful adult emergence was deteriorated by extract treated larvae. Ethyl acetate extracts of Pseudocalymma alliaceum, showed higher percentage of antifeedant, insecticidal and growth inhibition activities.Conclusions:This is the first report on S. litura and H. armigera. Further, the active compounds isolated from the ethyl acetate extracts will be useful for controlling economically important insect pests.

  10. Push-pull Strategy with Trap Crops, Neem and Nuclear Polyhedrosis Virus for Insecticide Resistance Management in Helicoverpa armigera (Hubner) in Cotton

    OpenAIRE

    P. Duraimurugan; A. Regupathy

    2005-01-01

    Insecticide resistance in Helicoverpa armigera (Hubner) is a major threat to cotton production in India. The virus infection was found to increase the susceptibility of H. armigera to the insecticides. But, use of Nuclear Polyhedrosis Virus (NPV) on a larger scale and on cotton due to leaf alkalinity poses certain practical problems. Hence, studies were carried out to assess the effects of push-pull strategy with trap crops, neem and NPV in cotton for the management of insecticide resistant H...

  11. Identification of a G protein-coupled receptor for pheromone biosynthesis activating neuropeptide from pheromone glands of the moth Helicoverpa zea

    OpenAIRE

    Choi, Man-Yeon; Fuerst, Emily-Jean; Rafaeli, Ada; Jurenka, Russell

    2003-01-01

    Pheromone biosynthesis-activating neuropeptide (PBAN), a peptide produced by the subesophageal ganglion, is used by a variety of moths to regulate pheromone production. PBAN acts directly on pheromone gland cells by using calcium and cAMP as second messengers. We have identified a gene encoding a G protein-coupled receptor (GPCR) from pheromone glands of the female moth Helicoverpa zea. The gene was identified based on sequence identity to a group of GPCRs from Drosoph...

  12. Bacillus subtillis RTSBA6 6.00, a new strain isolated from gut of Helicoverpa armigera (Lepidoptera: Noctuidae) produces chymotrypsin-like proteases

    OpenAIRE

    Shinde, Ashok A.; Shaikh, Faiyaz K.; Padul, Manohar V.; Kachole, Manvendra S.

    2012-01-01

    Exploring bacterial communities with proteolytic activity from the gut of the Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) insect pests was the purpose of this study. As initial efforts to achieve this goal here we report the isolation of new Bacillus subtillis RTSBA6 6.00 strain from the gut of H. armigera and demonstrated as proteases producer. Zymographic analysis revealed 12 proteolytic bands with apparent molecular weights ranging from 20 to 185 kDa. Although some activity was ...

  13. Assessment of beneficial role of an insectivorous bird, jungle babbler (Turdoides striatus predation, on Helicoverpa armigera infesting pigeon pea (Cajanus cajan crop

    Directory of Open Access Journals (Sweden)

    Bhavna Bharucha

    2010-04-01

    Full Text Available Jungle babbler (Turdoides striatus, a widely spread sub-tropical insectivorous passerine is considered beneficial to agro-ecosystem, as they devour voraciously on insect matter especially Helicoverpa armigera, the gram pod borer, a notorious pest infesting and causing heavy loses to crops like pigeon pea (Cajanus cajan which is a vital crop of semi-arid tropical and subtropical farming system, providing high quality vegetable protein. Helicoverpa is known to feed on flowers, pods, and seeds and is the most important biotic constraint affecting pigeon pea yields. Jungle babblers have a peculiar foraging style which helps expose the Helicoverpa larvae as well as pupae through various phenological stages of pigeon pea. For comparative assessment of their beneficial role and as a possible bio control agent, in Baroda city (State of Gaujarat, India, was studied, two crops of pigeon pea (insecticide treated and untreated (control were selected. In both treated and control crops, the number of jungle babblers were maximum in pigeon pea fields during october and november in both small pod stage and large pod stage which had heavy infestation of Helicoverpa. Least number of birds was seen during the flowering stage in September. Later in treatment crop three applications of Dunnate and Monocrotophos insecticide spray was done after which the pest population decreased which is reflected in number of birds in the field, while the bird number in control crops grew since insecticide spray was not done and number of larvae increased with the stage of the crop. Along with the main crop pigeon pea, comparative study was also done to see the food preference by these birds in crops like sorghum, maize, cow pea and ploughed and unploughed fields. Maximum number of birds was seen in unploughed field and least in sorghum suggesting that Helicoverpa is preferred food over sorghum grains thus pigeon pea and sorghum can be used as mixed crops to protect the crop from

  14. Assessment of beneficial role of an insectivorous bird, jungle babbler (Turdoides striatus predation, on Helicoverpa armigera infesting pigeon pea (Cajanus cajan crop

    Directory of Open Access Journals (Sweden)

    Bharucha Bhavna

    2010-06-01

    Full Text Available Jungle babbler (Turdoides striatus, a widely spread sub-tropical insectivorous passerine is considered beneficial to agro-ecosystem, as they devour voraciously on insect matter especially Helicoverpa armigera, the gram pod borer, a notorious pest infesting and causing heavy loses to crops like pigeon pea (Cajanus cajan which is a vital crop of semi-arid tropical and subtropical farming system, providing high quality vegetable protein. Helicoverpa is known to feed on flowers, pods, and seeds and is the most important biotic constraint affecting pigeon pea yields. Jungle babblers have a peculiar foraging style which helps expose the Helicoverpa larvae as well as pupae through various phenological stages of pigeon pea. For comparative assessment of their beneficial role and as a possible bio control agent, in Baroda city (State of Gaujarat, India, was studied, two crops of pigeon pea (insecticide treated and untreated (control were selected. In both treated and control crops, the number of jungle babblers were maximum in pigeon pea fields during october and november in both small pod stage and large pod stage which had heavy infestation of Helicoverpa. Least number of birds was seen during the flowering stage in September. Later in treatment crop three applications of Dunnate and Monocrotophos insecticide spray was done after which the pest population decreased which is reflected in number of birds in the field, while the bird number in control crops grew since insecticide spray was not done and number of larvae increased with the stage of the crop. Along with the main crop pigeon pea, comparative study was also done to see the food preference by these birds in crops like sorghum, maize, cow pea and ploughed and unploughed fields. Maximum number of birds was seen in unploughed field and least in sorghum suggesting that Helicoverpa is preferred food over sorghum grains thus pigeon pea

  15. Molecular identification of three novel glutaredoxin genes that play important roles in antioxidant defense in Helicoverpa armigera.

    Science.gov (United States)

    Zhang, Song-Dou; Shen, Zhong-Jian; Liu, Xiao-Ming; Li, Zhen; Zhang, Qing-Wen; Liu, Xiao-Xia

    2016-08-01

    Glutaredoxins (Grxs), also known as thioltransferases, play key roles in maintaining intracellular redox balance and protecting cells from oxidative damage in plants and mammals. We tested whether Grxs play important roles in antioxidant defense in insects using the moth, Helicoverpa armigera. We obtained the full-length cDNA sequences of three novel Grx genes, named HaGrx, HaGrx3, and HaGrx5. Sequence analysis indicated that HaGrx shared a high amino acid identity (58%-78%) and a CPYC motif of conserved redox activity with homologues from other selected insect species. In contrast, HaGrx3 and HaGrx5 both shared a CGF(S/G) motif, a conserved catalytic domain, with other orthologous genes. Quantitative real-time PCR results revealed that HaGrx, HaGrx3, and HaGrx5 exhibited temporally- and spatially-dependent patterns of expression. The mRNA expression of HaGrx, HaGrx3, and HaGrx5 was induced by various temperature stresses and H2O2 treatments. We further investigated the knockdown of HaGrx, HaGrx3, and HaGrx5 in H. armigera larvae and found that most of the selected antioxidant genes were up regulated. However, Tpx was down regulated, and further interpretation of the complementary functions of these antioxidant genes is still required. We also determined the effect of HaGrx, HaGrx3, and HaGrx5 knockdown on antioxidant enzymatic activity and metabolite content. The enzymatic activities of SOD, CAT, and POD, and the metabolite contents of hydrogen peroxide, ascorbate, protein carbonyl, and total GSH increased after RNAi mediated knockdown of HaGrx, HaGrx3, and HaGrx5. These results supported our hypothesis that HaGrx, HaGrx3, and HaGrx5 play important roles in antioxidant defense of Helicoverpa armigera and provided a theoretical basis for further in-depth study of physiological function in the insect glutaredoxin family genes.

  16. In vivo and in vitro effect of Acacia nilotica seed proteinase inhibitors on Helicoverpa armigera (Hübner) larvae

    Indian Academy of Sciences (India)

    S Ramesh Babu; B Subrahmanyam; Srinivasan; I M Santha

    2012-06-01

    Acacia nilotica proteinase inhibitor (AnPI) was isolated by ammonium sulphate precipitation followed by chromatography on DEAE-Sephadex A-25 and resulted in a purification of 10.68-fold with a 19.5% yield. Electrophoretic analysis of purified AnPI protein resolved into a single band with molecular weight of approximately 18.6+1.00 kDa. AnPI had high stability at different pH values (2.0 to 10.0) except at pH 5.0 and are thermolabile beyond 80°C for 10 min. AnPI exhibited effective against total proteolytic activity and trypsin-like activity, but did not show any inhibitory effect on chymotrypsin activity of midgut of Helicoverpa armigera. The inhibition kinetics studies against H. armigera gut trypsin are of non-competitive type. AnPI had low affinity for H. armigera gut trypsin when compared to SBTI. The partially purified and purified PI proteins-incorporated test diets showed significant reduction in mean larval and pupal weight of H. armigera. The results provide important clues in designing strategies by using the proteinase inhibitors (PIs) from the A. nilotica that can be expressed in genetically engineered plants to confer resistance to H. armigera.

  17. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Zhao, Zhuoya; Li, Yunhe; Xiao, Yutao; Ali, Abid; Dhiloo, Khalid Hussain; Chen, Wenbo; Wu, Kongming

    2016-01-01

    Crystal (Cry) proteins derived from Bacillus thuringiensis (Bt) have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem.

  18. Pigeonpea genotypes influence parasitization preference and survival and development of the Helicoverpa armigera larval parasitoid, Campoletis chlorideae.

    Science.gov (United States)

    Hugar, Shiddalingappa V; Sharma, Hari C; Basavan Goud, Kondikallu

    2014-01-01

    Studies were undertaken to identify pigeonpea, Cajanus cajan (L.) Millspaugh and the wild relative of pigeonpea, Cajanus scarabaeoides (L.) (accession ICPW 125,) genotypes that are hospitable to the pod borer, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larval parasitoid, Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae) for the management of this pest in pigeonpea based cropping systems. Percentage parasitization of the H. armigera larvae by the C. chlorideae females was greater under no-choice conditions than under multi-choice conditions because of forced parasitization under no-choice conditions. Lowest parasitization was recorded on the wild relative, ICPW 125, which may be due to long nonglandular hairs and low survival of H. armigera larvae. Parasitization of H. armigera larvae was greater under no-choice, dual-choice and/or multi-choice conditions on ICPL 87, ICPL 87119 and ICPL 87091, which are susceptible to H. armigera, than on the pod borer-resistant genotypes ICPL 332WR, ICPL 84060 and ICPB 2042; while survival and development of the parasitoid was better on H. armigera larvae fed on ICPL 87, ICPL 87119, LRG 41, ICP 7035 and ICPL 87091 than on ICPL 332WR, ICPL 84060, ICPB 2042 and ICPW 125. The genotypes ICPL 87, ICPL 87119, LRG 42 and ICPL 87091 that are hospitable to C. chloridae, are better suited for use in integrated pest management to minimize the losses due to H. armigera in pigeonpea. PMID:25110629

  19. Nitrate reductase and nitrite as additional components of defense system in pigeonpea (Cajanus cajan L.) against Helicoverpa armigera herbivory.

    Science.gov (United States)

    Kaur, Rimaljeet; Gupta, Anil Kumar; Taggar, Gaurav Kumar

    2014-10-01

    Amylase inhibitors serve as attractive candidates of defense mechanisms against insect attack. Therefore, the impediment of Helicoverpa armigera digestion can be the effective way of controlling this pest population. Nitrite was found to be a potent mixed non-competitive competitive inhibitor of partially purified α-amylase of H. armigera gut. This observation impelled us to determine the response of nitrite and nitrate reductase (NR) towards H. armigera infestation in nine pigeonpea genotypes (four moderately resistant, three intermediate and two moderately susceptible). The significant upregulation of NR in moderately resistant genotypes after pod borer infestation suggested NR as one of the factors that determine their resistance status against insect attack. The pod borer attack caused greater reduction of nitrate and significant accumulation of nitrite in moderately resistant genotypes. The activity of nitrite reductase (NiR) was also enhanced more in moderately resistant genotypes than moderately susceptible genotypes on account of H. armigera herbivory. Expression of resistance to H. armigera was further revealed when significant negative association between NR, NiR, nitrite and percent pod damage was observed. This is the first report that suggests nitrite to be a potent inhibitor of H. armigera α-amylase and also the involvement of nitrite and NR in providing resistance against H. armigera herbivory. PMID:25307464

  20. Targeting chitinase gene of Helicoverpa armigera by host-induced RNA interference confers insect resistance in tobacco and tomato.

    Science.gov (United States)

    Mamta; Reddy, K R K; Rajam, M V

    2016-02-01

    Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a devastating agricultural insect pest with broad spectrum of host range, causing million dollars crop loss annually. Limitations in the present conventional and transgenic approaches have made it crucial to develop sustainable and environmental friendly methods for crop improvement. In the present study, host-induced RNA interference (HI-RNAi) approach was used to develop H. armigera resistant tobacco and tomato plants. Chitinase (HaCHI) gene, critically required for insect molting and metamorphosis was selected as a potential target. Hair-pin RNAi construct was prepared from the conserved off-target free partial HaCHI gene sequence and was used to generate several HaCHI-RNAi tobacco and tomato plants. Northern hybridization confirmed the production of HaCHI gene-specific siRNAs in HaCHI-RNAi tobacco and tomato lines. Continuous feeding on leaves of RNAi lines drastically reduced the target gene transcripts and consequently, affected the overall growth and survival of H. armigera. Various developmental deformities were also manifested in H. armigera larvae after feeding on the leaves of RNAi lines. These results demonstrated the role of chitinase in insect development and potential of HI-RNAi for effective management of H. armigera.

  1. Genetic engineering of cotton with a novel cry2AX1 gene to impart insect resistance against Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Karunamurthy Dhivya

    2016-09-01

    Full Text Available Embryogenic calli of cotton (Coker310 were cocultivated with the Agrobacterium tumefaciens strain LBA4404 harbouring the codon-optimised, chimeric cry2AX1 gene consisting of sequences from cry2Aa and cry2Ac genes isolated from Indian strains of Bacillus thuringiensis. Forty-eight putative transgenic plants were regenerated, and PCR analysis of these plants revealed the presence of the cry2AX1 gene in 40 plants. Southern blot hybridisation analysis of selected transgenic plants confirmed stable T-DNA integration in the genome of transformed plants. The level of Cry2AX1 protein expression in PCR positive plants ranged from 4.9 to 187.5 ng g-1 of fresh tissue. A transgenic cotton event, TP31, expressing the cry2AX1 gene showed insecticidal activity of 56.66 per cent mortality against Helicoverpa armigera in detached leaf disc bioassay. These results indicate that the chimeric cry2AX1 gene expressed in transgenic cotton has insecticidal activity against H. armigera.

  2. Forecasting Helicoverpa populations in Australia: A comparison of regression based models and a bioclimatic based modelling approach

    Institute of Scientific and Technical Information of China (English)

    MYRONP.ZALUCKI; MICHAELJ.FURLONG

    2005-01-01

    Long-term forecasts of pest pressure are central to the effective management of many agricultural insect pests. In the eastern cropping regions of Australia, serious infestations of Helicoverpa punctigera (Wallenglen) and H. armigera (Hübner)(Lepidoptera:Noctuidae) are experienced annually. Regression analyses of a long series of light-trap catches of adult moths were used to describe the seasonal dynamics of both species. The size of the spring generation in eastern cropping zones could be related to rainfall in putative source areas in inland Australia. Subsequent generations could be related to the abundance of various crops in agricultural areas, rainfall and the magnitude of the spring population peak. As rainfall figured prominently as a predictor variable, and can itself be predicted using the Southern Oscillation Index (SOI), trap catches were also related to this variable. The geographic distribution of each species was modelled in relation to climate and CLIMEX was used to predict temporal variation in abundance at given putative source sites in inland Australia using historical meteorological data. These predictions were then correlated with subsequent pest abundance data in a major cropping region. The regression-based and bioclimatic-based approaches to predicting pest abundance are compared and their utility in predicting and interpreting pest dynamics are discussed.

  3. EAG and behavioral responses of Helicoverpa armigera males to volatiles from poplar leaves and their combinations with sex pheromone

    Institute of Scientific and Technical Information of China (English)

    邓建宇; 黄永平; 魏洪义; 杜家纬

    2004-01-01

    Electroantennogram (EAG) evaluation of selected compounds from wilted leaves ofblack poplar,Populus nigra,showed that phenyl acetaldehyde, methyl salicylate, (E)-2-hexenal elicited strong responses from male antennae of Helicoverpa armigera. When mixed with sex pheromone (Ph), some volatiles, e.g. phenyl acetaldehyde, benzyl alcohol,phenylethanol, methylsalicylate, linalool, benzaldehyde, (Z)-3-hexenol, (Z)-3-hexenylacetate, (Z)-6-nonenol, cineole, (E)-2-hexenal, and geraniol elicited stronger responses from male antennae than Ph alone. Wind tunnel bioassay demonstrated that various volatiles could either enhance or inhibit the effect of synthetic sex pheromone. (E)-2-hexenal, (Z)-3-hexenol and linalool in combination with Ph could not induce any male to land on source at all, whereas phenyl acetaldehyde, benzaldehyde, (Z)-6-nonenol and salicylaldehyde combined with Ph enhanced male response rates by 58.63%,50.33%, 51.85% and 127.78%, respectively, compared to Ph alone. These results suggested that some volatiles should modify sex pheromone caused behavior and that some of them could possibly be used as a tool for disrupting mating or for enhancing the effect of synthetic sex pheromone in the field.

  4. EAG and behavioral responses of Helicoverpa armigera males to volatiles from poplar leaves and their combinations with sex pheromone

    Institute of Scientific and Technical Information of China (English)

    邓建宇; 黄永平; 魏洪义

    2004-01-01

    Electroantennogram (EAG) evaluation of selected compounds from wilted leaves of black poplar, Populus nigra, showed that phenyl acetaldehyde, methyl salicylate, (E)-2-hexenal elicited strong responses from male antennae of Helicoverpa armigera. When mixed with sex pheromone (Ph), some volatiles, e.g. phenyl acetaldehyde, benzyl alcohol, phenylethanol, methylsalicylate, linalool, benzaldehyde, (Z)-3-hexenol, (Z)-3-hexenylacetate, (Z)-6-nonenol, cineole, (E)-2-hexenal, and geraniol elicited stronger responses from male antennae than Ph alone. Wind tunnel bioassay demonstrated that various volatiles could either enhance or inhibit the effect of synthetic sex pheromone. (E)-2-hexenal, (Z)-3-hexenol and linalool in combination with Ph could not induce any male to land on source at all, whereas phenyl acetaldehyde, benzaldehyde, (Z)-6-nonenol and salicylaldehyde combined with Ph enhanced male response rates by 58.63%, 50.33%, 51.85% and 127.78%, respectively, compared to Ph alone. These results suggested that some volatiles shouldmodify sex pheromone caused behavior and that some of them could possibly be used as a tool for disrupting mating or for enhancing the effect of synthetic sex pheromone in the field.

  5. Adaptation of Habrobracon hebetor (Hymenoptera: Braconidae) to Rearing on Ephestia kuehniella (Lepidoptera: Pyralidae) and Helicoverpa armigera (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Borzoui, Ehsan; Naseri, Bahram; Mohammadzadeh-Bidarani, Mozhgan

    2016-01-01

    Food characteristics strongly regulate digestive enzymatic activity of insects through direct influences on their midgut mechanisms. Insect performance is better on diets that contain nutrients in proportions that fit its digestive enzymes. Little is known about the influences of rearing history on parasitism success of Habrobracon hebetor Say. This research focused on the effect of nutrient regulation on survival, development, and parasitism of H. hebetor. Life history and digestive enzyme activity of fourth-stage larvae of H. hebetor were studied when reared on Ephestia kuehniella Zeller. This parasitoid was then introduced to Helicoverpa armigera (Hübner), and above-mentioned parameters were also studied in the first and fourth generations after transfer. In term of parasitism success, H. hebetor preferred E. kuehniella over He. armigera. When the first and fourth generations of He. armigera-reared H. hebetor were compared, the rearing history affected the life history and enzymatic activity of the parasitoid. A better performance of H. hebetor was achieved after it was reared on He. armigera for the four generations. Because, digestive α-amylase and general protease of the parasitoid were matched with the new host, it used reserve energy for a better performance. Thus, a better performance of H. hebetor could be obtained when the parasitoid was reared on its original host for at least four generations. PMID:26839317

  6. Relative Fitness of Helicoverpa armigera (Lepidoptera: Noctuidae) on Seven Host Plants: A Perspective for IPM in Brazil.

    Science.gov (United States)

    Reigada, C; Guimarães, K F; Parra, J R P

    2016-01-01

    The cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a widespread pest of many cultivated and wild plants in Europe, Africa, Asia, and Australia. In 2013, this species was reported in Brazil, attacking various host crops in the midwestern and northeastern regions of the country and is now found countrywide. Aiming to understand the effects of different host plants on the life cycle of H. armigera, we selected seven species of host plants that mature in different seasons and are commonly grown in these regions: cotton (Gossypium hirsutum, "FM993"), corn (Zea mays, "2B587"), soybean (Glycine max, "99R01"), rattlepods (Crotalaria spectabilis), millet (Pennisetum glaucum, "ADR300"), sorghum (Sorghum bicolor, "AGROMEN70G35"), and cowpea (Vigna unguiculata, "SEMPRE VERDE"). The development time of immatures, body weight, survivorship, and fecundity of H. armigera were evaluated on each host plant under laboratory conditions. The bollworms did not survive on corn, millet, or sorghum and showed very low survival rates on rattlepods. Survival rates were highest on soybean, followed by cotton and cowpea. The values for relative fitness found on soybean, cotton, cowpea, and rattlepods were 1, 0.5, 0.43, and 0.03, respectively. Survivorship, faster development time, and fecundity on soybean, cotton, and cowpea were positively correlated. Larger pupae and greater fecundity were found on soybean and cotton. The results indicated that soybean, cotton, and cowpea are the most suitable plants to support the reproduction of H. armigera in the field. PMID:26798139

  7. Cannibalism of Helicoverpa zea (Lepidoptera: Noctuidae) from Bacillus thuringiensis (Bt) transgenic corn versus non-Bt corn.

    Science.gov (United States)

    Chilcutt, Charles F

    2006-06-01

    Because of the importance of cannibalism in population regulation of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in corn, Zea mays L., it is useful to understand the interactions between Bacillus thuringiensis (Bt) transgenic corn and cannibalism. To determine the effects of Bt corn on cannibalism in H. zea, pairs of the same or different instars were taken from Bt or non-Bt corn and placed on artificial diet in proximity. Cannibalism occurred in 91% of pairs and was approximately 7% greater for pairs of larvae reared from Bt transgenic corn (95%) than from non-Bt corn (88%). Also, first instar by first instar pairs had a lower rate of cannibalism than other pairs. Time until cannibalism was not different for larvae from Bt corn versus non-Bt corn. Pupation rate of cannibals and surviving victims was not different for pairs from Bt corn versus non-Bt corn. Finally, cannibalism increased pupation rate of cannibals from both Bt and non-Bt corn by approximately 23 and 12%, respectively, although the increases were not significant. Thus, negative effects of Bt on larvae were compensated by increased cannibalism in comparison with larvae reared on non-Bt corn, which increased larval survival to levels comparable with larvae reared on non-Bt plants.

  8. Mutation of an aminopeptidase N gene is associated with Helicoverpa armigera resistance to Bacillus thuringiensis Cry1Ac toxin.

    Science.gov (United States)

    Zhang, Shaoping; Cheng, Hongmei; Gao, Yulin; Wang, Guirong; Liang, Gemei; Wu, Kongming

    2009-07-01

    A Cry1Ac-resistant strain (Bt-R) of Helicoverpa armigera, with 2971-fold resistance, was derived by selection with Cry1Ac toxin for 75 generations. We used cDNA-amplified fragment length polymorphism analysis to identify those genes differentially expressed in the Cry1Ac-resistant and -susceptible strains, which revealed 212 differentially expressed transcripts among 2000 screened cDNAs. Among these transcript-derived fragments (TDFs), 37 showed some homology to known sequences, including Aminopeptidase N (APN), which is expressed in the midgut epithelium and has been implicated as a Cry1A subfamily receptor in several moths, including H. armigera. We confirmed the TDF by RT-PCR and identified a deletion mutation of apn1 in the Bt-R strain. We expressed the TDF in bacteria. The partial HaAPN1-96S wild-type protein, bound to Cry1Ac on ligand blots, whereas HaAPN1-BtR did not. This suggested that HaAPN1 is a receptor for Bt Cry1Ac and that its deletion mutation is associated with Cry1Ac resistance in H. armigera. The absence of one binding site is responsible for its resistance to Cry1Ac. We developed an allele-specific PCR to monitor whether the apn1 gene in an H. armigera field population produced a similar mutation. No deleted mutants were found in 2250 individuals collected from the field in 2006-2007. PMID:19376227

  9. Ovicidal activity of botanical oil formulations against Helicoverpa armigera Hubner and Spodoptera litura Fabricius (Lepidoptera:Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    Susaimanickam Maria Packiam; Kathirvelu Baskar; Savarimuthu Ignacimuthu

    2012-01-01

    Objective: To evaluate the ovicidal activity of different botanical oil formulations againstHelicoverpa armigera and Spodoptera litura. Methods: Different botanical oils were formulated with different ratio to evaluate the ovicidal activity against H. armigera and S. litura at 5, 10, 15 and 20μl/L concentrations. Results: All the oil formulations showed the ovicidal activity against H. armigera and S. litura. The maximum ovicidal actvity of 76.74 and 69.36% was noticed at 20μl/L concentration in formulation 3 PONNEEM. Formulation 4 Pongam oil showed lower ovicidal activity of 31.34 and 24.76% against H. armigera and S. litura respectively. Among the formulations, PONNEEM exhibited statistically superior ovicidal activity against both insect pests. Conclusions: the present study clearly showed PONNEEM as a pontenial biopesticide to control the egg stage of economically important pests of H. armigera and S. litura. This is the first report for the ovicidal activity of PONNEEM against these two insect pests.

  10. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Zhuoya Zhao

    2016-07-01

    Full Text Available Crystal (Cry proteins derived from Bacillus thuringiensis (Bt have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem.

  11. A toxin-binding alkaline phosphatase fragment synergizes Bt toxin Cry1Ac against susceptible and resistant Helicoverpa armigera.

    Directory of Open Access Journals (Sweden)

    Wenbo Chen

    Full Text Available Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry proteins from the bacterium Bacillus thuringiensis (Bt in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50 of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase protein that binds Cry1Ac was associated with resistance to Cry1Ac in the four most resistant strains. A Cry1Ac-binding fragment of alkaline phosphatase from H. armigera (HaALP1f was not toxic by itself, but it increased mortality caused by Cry1Ac in a susceptible strain and in all five resistant strains. Although synergism of Bt toxins against susceptible insects by toxin-binding fragments of cadherin and aminopeptidase N has been reported previously, the results here provide the first evidence of synergism of a Bt toxin by a toxin-binding fragment of alkaline phosphatase. The results here also provide the first evidence of synergism of a Bt toxin by any toxin-binding peptide against resistant insects.

  12. A toxin-binding alkaline phosphatase fragment synergizes Bt toxin Cry1Ac against susceptible and resistant Helicoverpa armigera.

    Science.gov (United States)

    Chen, Wenbo; Liu, Chenxi; Xiao, Yutao; Zhang, Dandan; Zhang, Yongdong; Li, Xianchun; Tabashnik, Bruce E; Wu, Kongming

    2015-01-01

    Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry) proteins from the bacterium Bacillus thuringiensis (Bt) in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50) of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase protein that binds Cry1Ac was associated with resistance to Cry1Ac in the four most resistant strains. A Cry1Ac-binding fragment of alkaline phosphatase from H. armigera (HaALP1f) was not toxic by itself, but it increased mortality caused by Cry1Ac in a susceptible strain and in all five resistant strains. Although synergism of Bt toxins against susceptible insects by toxin-binding fragments of cadherin and aminopeptidase N has been reported previously, the results here provide the first evidence of synergism of a Bt toxin by a toxin-binding fragment of alkaline phosphatase. The results here also provide the first evidence of synergism of a Bt toxin by any toxin-binding peptide against resistant insects. PMID:25885820

  13. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Zhao, Zhuoya; Li, Yunhe; Xiao, Yutao; Ali, Abid; Dhiloo, Khalid Hussain; Chen, Wenbo; Wu, Kongming

    2016-01-01

    Crystal (Cry) proteins derived from Bacillus thuringiensis (Bt) have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem. PMID:27399776

  14. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera

    Science.gov (United States)

    Zhao, Zhuoya; Li, Yunhe; Xiao, Yutao; Ali, Abid; Dhiloo, Khalid Hussain; Chen, Wenbo; Wu, Kongming

    2016-01-01

    Crystal (Cry) proteins derived from Bacillus thuringiensis (Bt) have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem. PMID:27399776

  15. Expression Analysis and Binding Assays in the Chemosensory Protein Gene Family Indicate Multiple Roles in Helicoverpa armigera.

    Science.gov (United States)

    Li, Zhao-Qun; Zhang, Shuai; Luo, Jun-Yu; Zhu, Jing; Cui, Jin-Jie; Dong, Shuang-Lin

    2015-05-01

    Chemosensory proteins (CSPs) have been proposed to capture and transport hydrophobic chemicals to receptors on sensory neurons. We identified and cloned 24 CSP genes to better understand the physiological function of CSPs in Helicoverpa armigera. Quantitative real-time polymerase chain reaction assays indicate that CSP genes are ubiquitously expressed in adult H. armigera tissues. Broad expression patterns in adult tissues suggest that CSPs are involved in a diverse range of cellular processes, including chemosensation as well as other functions not related to chemosensation. The H. armigera CSPs that were highly transcribed in sensory organs or pheromone glands (HarmCSPs 6, 9, 18, 19), were recombinantly expressed in bacteria to explore their function. Fluorescent competitive binding assays were used to measure the binding affinities of these CSPs against 85 plant volatiles and 4 pheromone components. HarmCSP6 displays high binding affinity for pheromone components, whereas the other three proteins do not show affinities for any of the compounds tested. HarmCSP6 is expressed in numerous cells located in or close to long sensilla trichodea on the antennae of both males and females. These results suggest that HarmCSP6 may be involved in transporting female sex pheromones in H. armigera. PMID:25893790

  16. Species From the Heliothinae Complex (Lepidoptera: Noctuidae) in Tucumán, Argentina, an Update of Geographical Distribution of Helicoverpa armigera

    Science.gov (United States)

    Murúa, M. Gabriela; Cazado, Lucas E.; Casmuz, Augusto; Herrero, M. Inés; Villagrán, M. Elvira; Vera, Alejandro; Sosa-Gómez, Daniel R.; Gastaminza, Gerardo

    2016-01-01

    The Heliothinae complex in Argentina encompasses Helicoverpa gelotopoeon (Dyar), Helicoverpa zea (Boddie), Helicoverpa armigera (Hübner), and Chloridea virescens (Fabricius). In Tucumán, the native species H. gelotopoeon is one of the most voracious soybean pests and also affects cotton and chickpea, even more in soybean-chickpea succession cropping systems. Differentiation of the Heliothinae complex in the egg, larva, and pupa stages is difficult. Therefore, the observation of the adult wing pattern design and male genitalia is useful to differentiate species. The objective of this study was to identify the species of the Heliothinae complex, determine population fluctuations of the Heliothinae complex in soybean and chickpea crops using male moths collected in pheromone traps in Tucuman province, and update the geographical distribution of H. armigera in Argentina. The species found were H. gelotopoeon, H. armigera, H. zea, and C. virescens. Regardless of province, county, crop, and year, the predominant species was H. gelotopoeon. Considering the population dynamics of H. gelotopoeon and H. armigera in chickpea and soybean crops, H. gelotopoeon was the most abundant species in both crops, in all years sampled, and the differences registered were significant. On the other hand, according to the Sistema Nacional Argentino de Vigilancia y Monitoreo de Plagas (SINAVIMO) database and our collections, H. armigera was recorded in eight provinces and 20 counties of Argentina, and its larvae were found on soybean, chickpea, sunflower crops and spiny plumeless thistle (Carduus acanthoides). This is the first report of H. armigera in sunflower and spiny plumeless thistle in Argentina. PMID:27324588

  17. Species From the Heliothinae Complex (Lepidoptera: Noctuidae) in Tucumán, Argentina, an Update of Geographical Distribution of Helicoverpa armigera.

    Science.gov (United States)

    Murúa, M Gabriela; Cazado, Lucas E; Casmuz, Augusto; Herrero, M Inés; Villagrán, M Elvira; Vera, Alejandro; Sosa-Gómez, Daniel R; Gastaminza, Gerardo

    2016-01-01

    The Heliothinae complex in Argentina encompasses Helicoverpa gelotopoeon (Dyar), Helicoverpa zea (Boddie), Helicoverpa armigera (Hübner), and Chloridea virescens (Fabricius). In Tucumán, the native species H. gelotopoeon is one of the most voracious soybean pests and also affects cotton and chickpea, even more in soybean-chickpea succession cropping systems. Differentiation of the Heliothinae complex in the egg, larva, and pupa stages is difficult. Therefore, the observation of the adult wing pattern design and male genitalia is useful to differentiate species. The objective of this study was to identify the species of the Heliothinae complex, determine population fluctuations of the Heliothinae complex in soybean and chickpea crops using male moths collected in pheromone traps in Tucuman province, and update the geographical distribution of H. armigera in Argentina. The species found were H. gelotopoeon, H. armigera, H. zea, and C. virescens. Regardless of province, county, crop, and year, the predominant species was H. gelotopoeon Considering the population dynamics of H. gelotopoeon and H. armigera in chickpea and soybean crops, H. gelotopoeon was the most abundant species in both crops, in all years sampled, and the differences registered were significant. On the other hand, according to the Sistema Nacional Argentino de Vigilancia y Monitoreo de Plagas (SINAVIMO) database and our collections, H. armigera was recorded in eight provinces and 20 counties of Argentina, and its larvae were found on soybean, chickpea, sunflower crops and spiny plumeless thistle (Carduus acanthoides). This is the first report of H. armigera in sunflower and spiny plumeless thistle in Argentina. PMID:27324588

  18. Species From the Heliothinae Complex (Lepidoptera: Noctuidae) in Tucumán, Argentina, an Update of Geographical Distribution of Helicoverpa armigera.

    Science.gov (United States)

    Murúa, M Gabriela; Cazado, Lucas E; Casmuz, Augusto; Herrero, M Inés; Villagrán, M Elvira; Vera, Alejandro; Sosa-Gómez, Daniel R; Gastaminza, Gerardo

    2016-01-01

    The Heliothinae complex in Argentina encompasses Helicoverpa gelotopoeon (Dyar), Helicoverpa zea (Boddie), Helicoverpa armigera (Hübner), and Chloridea virescens (Fabricius). In Tucumán, the native species H. gelotopoeon is one of the most voracious soybean pests and also affects cotton and chickpea, even more in soybean-chickpea succession cropping systems. Differentiation of the Heliothinae complex in the egg, larva, and pupa stages is difficult. Therefore, the observation of the adult wing pattern design and male genitalia is useful to differentiate species. The objective of this study was to identify the species of the Heliothinae complex, determine population fluctuations of the Heliothinae complex in soybean and chickpea crops using male moths collected in pheromone traps in Tucuman province, and update the geographical distribution of H. armigera in Argentina. The species found were H. gelotopoeon, H. armigera, H. zea, and C. virescens. Regardless of province, county, crop, and year, the predominant species was H. gelotopoeon Considering the population dynamics of H. gelotopoeon and H. armigera in chickpea and soybean crops, H. gelotopoeon was the most abundant species in both crops, in all years sampled, and the differences registered were significant. On the other hand, according to the Sistema Nacional Argentino de Vigilancia y Monitoreo de Plagas (SINAVIMO) database and our collections, H. armigera was recorded in eight provinces and 20 counties of Argentina, and its larvae were found on soybean, chickpea, sunflower crops and spiny plumeless thistle (Carduus acanthoides). This is the first report of H. armigera in sunflower and spiny plumeless thistle in Argentina.

  19. Antifeedant, larvicidal and growth inhibitory effects of ononitol monohydrate isolated from Cassia tora L. against Helicoverpa armigera (Hub.) and Spodoptera litura (Fab.) (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Baskar, Kathirvelu; Ignacimuthu, Savarimuthu

    2012-07-01

    Ononitol monohydrate isolated from the ethyl acetate extract of Cassia tora L. using column chromatography was evaluated for its antifeedant, larvicidal and growth inhibitory activities against Helicoverpa armigera and Spodoptera litura at different concentrations of 125, 250, 500 and 1000 ppm. Leaf disc no-choice method was used for the bioassay. The compound showed significant antifeedant, larvicidal and pupicidal activities against H. armigera and S. litura. The compound also prolonged the larval-pupal duration of the insect at all the tested concentrations. The activities were concentration dependent for both the insects. Ononitol could be used as an agent to prepare botanical new pesticidal formulations.

  20. Binding site alteration is responsible for field-isolated resistance to Bacillus thuringiensis Cry2A insecticidal proteins in two Helicoverpa species.

    Directory of Open Access Journals (Sweden)

    Silvia Caccia

    Full Text Available BACKGROUND: Evolution of resistance by target pests is the main threat to the long-term efficacy of crops expressing Bacillus thuringiensis (Bt insecticidal proteins. Cry2 proteins play a pivotal role in current Bt spray formulations and transgenic crops and they complement Cry1A proteins because of their different mode of action. Their presence is critical in the control of those lepidopteran species, such as Helicoverpa spp., which are not highly susceptible to Cry1A proteins. In Australia, a transgenic variety of cotton expressing Cry1Ac and Cry2Ab (Bollgard II comprises at least 80% of the total cotton area. Prior to the widespread adoption of Bollgard II, the frequency of alleles conferring resistance to Cry2Ab in field populations of Helicoverpa armigera and Helicoverpa punctigera was significantly higher than anticipated. Colonies established from survivors of F(2 screens against Cry2Ab are highly resistant to this toxin, but susceptible to Cry1Ac. METHODOLOGY/PRINCIPAL FINDINGS: Bioassays performed with surface-treated artificial diet on neonates of H. armigera and H. punctigera showed that Cry2Ab resistant insects were cross-resistant to Cry2Ae while susceptible to Cry1Ab. Binding analyses with (125I-labeled Cry2Ab were performed with brush border membrane vesicles from midguts of Cry2Ab susceptible and resistant insects. The results of the binding analyses correlated with bioassay data and demonstrated that resistant insects exhibited greatly reduced binding of Cry2Ab toxin to midgut receptors, whereas no change in (125I-labeled-Cry1Ac binding was detected. As previously demonstrated for H. armigera, Cry2Ab binding sites in H. punctigera were shown to be shared by Cry2Ae, which explains why an alteration of the shared binding site would lead to cross-resistance between the two Cry2A toxins. CONCLUSION/SIGNIFICANCE: This is the first time that a mechanism of resistance to the Cry2 class of insecticidal proteins has been reported

  1. Negative Effects of a Nonhost Proteinase Inhibitor of ~19.8 kDa from Madhuca indica Seeds on Developmental Physiology of Helicoverpa armigera (Hübner)

    OpenAIRE

    Farrukh Jamal; Dushyant Singh; Pandey, Prabhash K.

    2014-01-01

    An affinity purified trypsin inhibitor from the seed flour extracts of Madhuca indica (MiTI) on denaturing polyacrylamide gel electrophoresis showed that MiTI consisted of a single polypeptide chain with molecular mass of ~19.8 kDa. MiTI inhibited the total proteolytic and trypsin-like activities of the midgut proteinases of Helicoverpa armigera larvae by 87.51% and 76.12%, respectively, at concentration of 5 µg/mL with an IC50 of 1.75 µg/mL against trypsin like midgut proteinases. The enzyme...

  2. Novel genotypes of the Helicoverpa armigera single nucleopolyhedrovirus (HearSNPV), method for the production thereof, and use of same as a biological control agent

    OpenAIRE

    Arrizubieta, Maite; Oihane, Simón; Caballero, Primitivo; Williams, Trevor G.

    2015-01-01

    Se describen dos nuevos genotipos del nucleopoliedrovirus simple de Helicoverpa armigera, HearSNPV, HearSNPV-SP1B y HearSNPV-LB6, cada uno procedente de mezclas de genotipos obtenidas de localizaciones y cultivos diferentes. Cada uno de ellos tiene una actividad insecticida específica frente a larvas de H. armigera comparable a la de los insecticidas comerciales habituales. Además, la mezcla de los dos genotipos, particularmente en proporción 1:1 con viriones co-ocluidos de genotipos mezclado...

  3. Nuevos genotipos del nucleopoliedrovirus simple de Helicoverpa armigera (HearSNPV), procedimiento para su producción y uso como agente de control biológico

    OpenAIRE

    Arrizubieta, Maite; Oihane, Simón; Caballero, Primitivo; Williams, Trevor G.

    2014-01-01

    Se describen dos nuevos genotipos del nucleopoliedrovirus simple de Helicoverpa armigera, HearSNPV, HearSNPV-SP1B y HearSNPV-LB6, cada uno procedente de mezclas de genotipos obtenidas de localizaciones y cultivos diferentes. Cada uno de ellos tiene una actividad insecticida específica frente a larvas de H. armigera comparable a la de los insecticidas comerciales habituales. Además, la mezcla de los dos genotipos, particularmente en proporción 1:1 con viriones co-ocluidos de genotipos mezclado...

  4. Elevated CO2 reduces the resistance and tolerance of tomato plants to Helicoverpa armigera by suppressing the JA signaling pathway.

    Directory of Open Access Journals (Sweden)

    Huijuan Guo

    Full Text Available Both resistance and tolerance, which are two strategies that plants use to limit biotic stress, are affected by the abiotic environment including atmospheric CO(2 levels. We tested the hypothesis that elevated CO(2 would reduce resistance (i.e., the ability to prevent damage but enhance tolerance (i.e., the ability to regrow and compensate for damage after the damage has occurred of tomato plants to the cotton bollworm, Helicoverpa armigera. The results showed that elevated CO(2 reduced resistance by decreasing the jasmonic acid (JA level and activities of lipoxygenase, proteinase inhibitors, and polyphenol oxidase in wild-type (WT plants infested with H. armigera. Consequently, the activities of total protease, trypsin-like enzymes, and weak and active alkaline trypsin-like enzymes increased in the midgut of H. armigera when fed on WT plants grown under elevated CO(2. Unexpectedly, the tolerance of the WT to H. armigera (in terms of photosynthetic rate, activity of sucrose phosphate synthases, flower number, and plant biomass and height was also reduced by elevated CO(2. Under ambient CO(2, the expression of resistance and tolerance to H. armigera was much greater in wild type than in spr2 (a JA-deficient genotype plants, but elevated CO(2 reduced these differences of the resistance and tolerance between WT and spr2 plants. The results suggest that the JA signaling pathway contributes to both plant resistance and tolerance to herbivorous insects and that by suppressing the JA signaling pathway, elevated CO(2 will simultaneously reduce the resistance and tolerance of tomato plants.

  5. Functional response of Chrysoperla carnea (Neuroptera: Chrysopidae) to Helicoverpa armigera (Lepidoptera: Noctuidae): Effect of prey and predator stages

    Institute of Scientific and Technical Information of China (English)

    Mehdi Hassanpour; Jafar Mohaghegh; Shahzad Iranipour; Gadir Nouri-Ganbalani; Annie Enkegaard

    2011-01-01

    Understanding predator-prey interactions has a pivotal role in biological control programs. This study evaluated the functional response of three larval instars of the green lacewing, Chrysoperla carnea (Stephens), preying upon eggs and first instar larvae of the cotton bollworm, Helicoverpa armigera Hilbner. The first and second instar larvae of C. carnea exhibited typeⅡ functional responses against both prey stages. However, the third instar larvae of C. carnea showed a typeⅡ functional response to the first instar larvae of H. armigera, but a typeⅢ functional response to the eggs. For the first instar larvae of C. carnea, the attack rate on H. armigera eggs was significantly higher than that on the larvae, whereas the attack rate of the second instar C. carnea on H. armigera larvae was significantly higher than that on the eggs. For the third instar larvae of C. carnea, the attack rate on the larvae was 1.015± 0.278/h, and the attack coefficient on the eggs was 0.036± 0.005. The handling times of the third instar larvae on larvae and eggs were 0.087± 0.009 and 0.071± 0.001 h, respectively. The highest predation rate was found for the third instar larvae of C. carnea on H. armigera eggs. Results of this study revealed that the larvae of C. carnea, especially the third instar, had a good predation potential in controlling H. armigera eggs and larvae. However, for a comprehensive estimation of the bio-control abilities of C. carnea toward//, armigera, further field-based studies are needed.

  6. Isotopes and trace elements as natal origin markers of Helicoverpa armigera--an experimental model for biosecurity pests.

    Directory of Open Access Journals (Sweden)

    Peter W Holder

    Full Text Available Protecting a nation's primary production sector and natural estate is heavily dependent on the ability to determine the risk presented by incursions of exotic insect species. Identifying the geographic origin of such biosecurity breaches can be crucial in determining this risk and directing the appropriate operational responses and eradication campaigns, as well as ascertaining incursion pathways. Reading natural abundance biogeochemical markers using mass spectrometry is a powerful tool for tracing ecological pathways as well as provenance determination of commercial products and items of forensic interest. However, application of these methods to trace insects has been underutilised to date and our understanding in this field is still in a phase of basic development. In addition, biogeochemical markers have never been considered in the atypical situation of a biosecurity incursion, where sample sizes are often small, and of unknown geographic origin and plant host. These constraints effectively confound the interpretation of the one or two isotope geo-location markers systems that are currently used, which are therefore unlikely to achieve the level of provenance resolution required in biosecurity interceptions. Here, a novel approach is taken to evaluate the potential for provenance resolution of insect samples through multiple biogeochemical markers. The international pest, Helicoverpa armigera, has been used as a model species to assess the validity of using naturally occurring δ2H, 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb isotope ratios and trace element concentration signatures from single moth specimens for regional assignment to natal origin. None of the biogeochemical markers selected were individually able to separate moths from the different experimental regions (150-3000 km apart. Conversely, using multivariate analysis, the region of origin was correctly identified for approximately 75% of individual H. armigera samples. The

  7. Isotopes and Trace Elements as Natal Origin Markers of Helicoverpa armigera – An Experimental Model for Biosecurity Pests

    Science.gov (United States)

    Holder, Peter W.; Armstrong, Karen; Van Hale, Robert; Millet, Marc-Alban; Frew, Russell; Clough, Timothy J.; Baker, Joel A.

    2014-01-01

    Protecting a nation's primary production sector and natural estate is heavily dependent on the ability to determine the risk presented by incursions of exotic insect species. Identifying the geographic origin of such biosecurity breaches can be crucial in determining this risk and directing the appropriate operational responses and eradication campaigns, as well as ascertaining incursion pathways. Reading natural abundance biogeochemical markers using mass spectrometry is a powerful tool for tracing ecological pathways as well as provenance determination of commercial products and items of forensic interest. However, application of these methods to trace insects has been underutilised to date and our understanding in this field is still in a phase of basic development. In addition, biogeochemical markers have never been considered in the atypical situation of a biosecurity incursion, where sample sizes are often small, and of unknown geographic origin and plant host. These constraints effectively confound the interpretation of the one or two isotope geo-location markers systems that are currently used, which are therefore unlikely to achieve the level of provenance resolution required in biosecurity interceptions. Here, a novel approach is taken to evaluate the potential for provenance resolution of insect samples through multiple biogeochemical markers. The international pest, Helicoverpa armigera, has been used as a model species to assess the validity of using naturally occurring δ2H, 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb isotope ratios and trace element concentration signatures from single moth specimens for regional assignment to natal origin. None of the biogeochemical markers selected were individually able to separate moths from the different experimental regions (150–3000 km apart). Conversely, using multivariate analysis, the region of origin was correctly identified for approximately 75% of individual H. armigera samples. The geographic resolution

  8. The potential distribution of invading Helicoverpa armigera in North America: is it just a matter of time?

    Directory of Open Access Journals (Sweden)

    Darren J Kriticos

    Full Text Available Helicoverpa armigera has recently invaded South and Central America, and appears to be spreading rapidly. We update a previously developed potential distribution model to highlight the global invasion threat, with emphasis on the risks to the United States. The continued range expansion of H. armigera in Central America is likely to change the invasion threat it poses to North America qualitatively, making natural dispersal from either the Caribbean islands or Mexico feasible. To characterise the threat posed by H. armigera, we collated the value of the major host crops in the United States growing within its modelled potential range, including that area where it could expand its range during favourable seasons. We found that the annual value of crops that would be exposed to H. armigera totalled approximately US$78 billion p.a., with US$843 million p.a. worth growing in climates that are optimal for the pest. Elsewhere, H. armigera has developed broad-spectrum pesticide resistance; meaning that if it invades the United States, protecting these crops from significant production impacts could be challenging. It may be cost-effective to undertake pre-emptive biosecurity activities such as slowing the spread of H. armigera throughout the Americas, improving the system for detecting H. armigera, and methods for rapid identification, especially distinguishing between H. armigera, H. zea and potential H. armigera x H. zea hybrids. Developing biological control programs, especially using inundative techniques with entomopathogens and parasitoids could slow the spread of H. armigera, and reduce selective pressure for pesticide resistance. The rapid spread of H. armigera through South America into Central America suggests that its spread into North America is a matter of time. The likely natural dispersal routes preclude aggressive incursion responses, emphasizing the value of preparatory communication with agricultural producers in areas suitable for

  9. The seesaw effect of winter temperature change on the recruitment of cotton bollworms Helicoverpa armigera through mismatched phenology.

    Science.gov (United States)

    Reddy, Gadi V P; Shi, Peijian; Hui, Cang; Cheng, Xiaofei; Ouyang, Fang; Ge, Feng

    2015-12-01

    Knowing how climate change affects the population dynamics of insect pests is critical for the future of integrated pest management. Rising winter temperatures from global warming can drive increases in outbreaks of some agricultural pests. In contrast, here we propose an alternative hypothesis that both extremely cold and warm winters can mismatch the timing between the eclosion of overwintering pests and the flowering of key host plants. As host plants normally need higher effective cumulative temperatures for flowering than insects need for eclosion, changes in flowering time will be less dramatic than changes in eclosion time, leading to a mismatch of phenology on either side of the optimal winter temperature. We term this the "seesaw effect." Using a long-term dataset of the Old World cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in northern China, we tested this seesaw hypothesis by running a generalized additive model for the effects of the third generation moth in the preceding year, the winter air temperature, the number of winter days below a critical temperature and cumulative precipitation during winter on the demography of the overwintering moth. Results confirmed the existence of the seesaw effect of winter temperature change on overwintering populations. Pest management should therefore consider the indirect effect of changing crop phenology (whether due to greenhouse cultivation or to climate change) on pest outbreaks. As arthropods from mid- and high latitudes are actually living in a cooler thermal environment than their physiological optimum in contrast to species from lower latitudes, the effects of rising winter temperatures on the population dynamics of arthropods in the different latitudinal zones should be considered separately. The seesaw effect makes it more difficult to predict the average long-term population dynamics of insect pests at high latitudes due to the potential sharp changes in annual growth rates

  10. Bt Maize Seed Mixtures for Helicoverpa zea (Lepidoptera: Noctuidae): Larval Movement, Development, and Survival on Non-transgenic Maize.

    Science.gov (United States)

    Burkness, Eric C; Cira, T M; Moser, S E; Hutchison, W D

    2015-12-01

    In 2012 and 2013, field trials were conducted near Rosemount, MN, to assess the movement and development of Helicoverpa zea (Boddie) larvae on non-Bt refuge corn plants within a seed mixture of non-Bt and Bt corn. The Bt corn hybrid expressed three Bt toxins-Cry1Ab, Cry1F, and Vip3A. As the use of seed mixtures for insect resistance management (IRM) continues to be implemented, it is necessary to further characterize how this IRM approach impacts resistance development in ear-feeding Lepidopteran pests. The potential for Bt pollen movement and cross pollination of the non-Bt ears in a seed mixture may lead to Bt toxin exposure to larvae developing on those refuge ears. Larval movement and development by H. zea, feeding on non-Bt refuge plants adjacent to either transgenic Bt or non-Bt plants, were measured to investigate the potential for unintended Bt exposure. Non-Bt plants were infested with H. zea eggs and subplots were destructively sampled twice per week within each treatment to assess larval development, location, and kernel injury. Results indicate that H. zea larval movement between plants is relatively low, ranging from 2-16% of larvae, and occurs mainly after reaching the second instar. Refuge plants in seed mixtures did not produce equivalent numbers of H. zea larvae, kernel injury, and larval development differed as compared with a pure stand of non-Bt plants. This suggests that there may be costs to larvae developing on refuge plants within seed mixtures and additional studies are warranted to define potential impacts.

  11. Risk assessment for Helicoverpa zea (Lepidoptera: Noctuidae) resistance on dual-gene versus single-gene corn.

    Science.gov (United States)

    Edwards, Kristine T; Caprio, Michael A; Allen, K Clint; Musser, Fred R

    2013-02-01

    Recent Environmental Protection Agency (EPA) decisions regarding resistance management in Bt-cropping systems have prompted concern in some experts that dual-gene Bt-corn (CrylA.105 and Cry2Ab2 toxins) may result in more rapid selection for resistance in Helicoverpa zea (Boddie) than single-gene Bacillus thuringiensis (Bt)-corn (CrylAb toxin). The concern is that Bt-toxin longevity could be significantly reduced with recent adoption of a natural refuge for dual-gene Bt-cotton (CrylAc and Cry2Ab2 toxins) and concurrent reduction in dual-gene corn refuge from 50 to 20%. A population genetics framework that simulates complex landscapes was applied to risk assessment. Expert opinions on effectiveness of several transgenic corn and cotton varieties were captured and used to assign probabilities to different scenarios in the assessment. At least 350 replicate simulations with randomly drawn parameters were completed for each of four risk assessments. Resistance evolved within 30 yr in 22.5% of simulations with single-gene corn and cotton with no volunteer corn. When volunteer corn was added to this assessment, risk of resistance evolving within 30 yr declined to 13.8%. When dual-gene Bt-cotton planted with a natural refuge and single-gene corn planted with a 50% structured refuge was simulated, simultaneous resistance to both toxins never occurred within 30 yr, but in 38.5% of simulations, resistance evolved to toxin present in single-gene Bt-corn (CrylAb). When both corn and cotton were simulated as dual-gene products, cotton with a natural refuge and corn with a 20% refuge, 3% of simulations evolved resistance to both toxins simultaneously within 30 yr, while 10.4% of simulations evolved resistance to CrylAb/c toxin.

  12. Influence of Dual-Bt Protein Corn on Bollworm, Helicoverpa zea (Boddie), Survivorship on Bollgard II Cotton.

    Science.gov (United States)

    Von Kanel, M B; Gore, J; Catchot, A; Cook, D; Musser, F; Caprio, M

    2016-04-01

    Similar Cry proteins are expressed in both Bt corn, Zea mays L., and cotton, Gossypium hirsutum (L.), commercial production systems. At least one generation of corn earworm, Helicoverpa zea (Boddie), completes development on field corn in the Mid-South before dispersing across the landscape into other crop hosts like cotton. A concern is that Bt corn hybrids may result in selection for H. zea populations with a higher probability of causing damage to Bt cotton. The objective of this study was to determine the susceptibility of H. zea offspring from moths that developed on non-Bt and VT Triple Pro (VT3 PRO) field corn to lyophilized Bollgard II cotton tissue expressing Cry1Ac and Cry2Ab. Offspring of individuals reared on VT3 PRO expressing Cry1A.105 and Cry2Ab had a significantly higher LC50 two out of the three years this study was conducted. Excess larvae were placed on artificial diet and allowed to pupate to determine if there were any inheritable fitness costs associated with parental development on VT3 PRO corn. Offspring resulting from males collected from VT3 PRO had significantly lower pupal weight and longer pupal duration compared with offspring of individuals collected from non-Bt corn. However, offspring from females collected from VT3 PRO were not different from non-Bt offspring. Paternal influence on offspring in insects is not commonly observed, but illustrates the side effects of development on a transgenic plant expressing less than a high dose, 25 times the concentration needed to kill susceptible larvae.

  13. Isolation and Characterization of Gut Bacterial Proteases Involved in Inducing Pathogenicity of Bacillus thuringiensis Toxin in Cotton Bollworm, Helicoverpa armigera

    Science.gov (United States)

    Regode, Visweshwar; Kuruba, Sreeramulu; Mohammad, Akbar S.; Sharma, Hari C.

    2016-01-01

    Bacillus thuringiensis toxin proteins are deployed in transgenic plants for pest management. The present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive Cry1Ac protoxin (pro-Cry1Ac) to active toxin in Helicoverpa armigera. Bacterial strains were isolated from H. armigera midgut and screened for their proteolytic activation toward pro-Cry1Ac. Among 12 gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three isolates (IVS1, IVS2, and IVS3) were found to be involved in the proteolytic conversion of pro-Cry1Ac into active toxin. The proteases from IVS1, IVS2, and IVS3 isolates were purified to 11.90-, 15.50-, and 17.20-fold, respectively. The optimum pH and temperature for gut bacterial protease activity was 8.0 and 40°C. Maximum inhibition of total proteolytic activity was exerted by phenylmethane sulfonyl fluoride followed by EDTA. Fluorescence zymography revealed that proteases from IVS1, IVS2, and IVS3 were chymotrypsin-like and showing protease band at ~15, 65, and 15 kDa, respectively. Active Cry1Ac formed from processing pro-Cry1Ac by gut bacterial proteases exhibited toxicity toward H. armigera. The gut bacterial isolates IVS1, IVS2, and IVS3 showed homology with B. thuringiensis (CP003763.1), Vibrio fischeri (CP000020.2), and Escherichia coli (CP011342.1), respectively. Proteases produced by midgut bacteria are involved in proteolytic processing of B. thuringiensis protoxin and play a major role in inducing pathogenicity of B. thuringiensis toxins in H. armigera. PMID:27766093

  14. The expression of proteins involved in digestion and detoxification are regulated in Helicoverpa armigera to cope up with chlorpyrifos insecticide.

    Science.gov (United States)

    Dawkar, Vishal V; Chikate, Yojana R; More, Tushar H; Gupta, Vidya S; Giri, Ashok P

    2016-02-01

    Helicoverpa armigera is a key pest in many vital crops, which is mainly controlled by chemical strategies. To manage this pest is becoming challenging due to its ability and evolution of resistance against insecticides. Further, its subsequent spread on nonhost plant is remarkable in recent times. Hence, decoding resistance mechanism against phytochemicals and synthetic insecticides is a major challenge. The present work describes that the digestion, defense and immunity related enzymes are associated with chlorpyrifos resistance in H. armigera. Proteomic analysis of H. armigera gut tissue upon feeding on chlorpyrifos containing diet (CH) and artificial diet (AD) using nano-liquid chromatography-mass spectrometry identified upregulated 23-proteins in CH fed larvae. Database searches combined with gene ontology analysis revealed that the identified gut proteins engrossed in digestion, proteins crucial for immunity, adaptive responses to stress, and detoxification. Biochemical and quantitative real-time polymerase chain reaction analysis of candidate proteins indicated that insects were struggling to get nutrients and energy in presence of CH, while at the same time endeavoring to metabolize chlorpyrifos. Moreover, we proposed a potential processing pathway of chlorpyrifos in H. armigera gut by examining the metabolites using gas chromatography-mass spectrometry. H. armigera exhibit a range of intriguing behavioral, morphological adaptations and resistance to insecticides by regulating expression of proteins involved in digestion and detoxification mechanisms to cope up with chlorpyrifos. In these contexts, as gut is a rich repository of biological information; profound analysis of gut tissues can give clues of detoxification and resistance mechanism in insects. PMID:25284010

  15. Bt Maize Seed Mixtures for Helicoverpa zea (Lepidoptera: Noctuidae): Larval Movement, Development, and Survival on Non-transgenic Maize.

    Science.gov (United States)

    Burkness, Eric C; Cira, T M; Moser, S E; Hutchison, W D

    2015-12-01

    In 2012 and 2013, field trials were conducted near Rosemount, MN, to assess the movement and development of Helicoverpa zea (Boddie) larvae on non-Bt refuge corn plants within a seed mixture of non-Bt and Bt corn. The Bt corn hybrid expressed three Bt toxins-Cry1Ab, Cry1F, and Vip3A. As the use of seed mixtures for insect resistance management (IRM) continues to be implemented, it is necessary to further characterize how this IRM approach impacts resistance development in ear-feeding Lepidopteran pests. The potential for Bt pollen movement and cross pollination of the non-Bt ears in a seed mixture may lead to Bt toxin exposure to larvae developing on those refuge ears. Larval movement and development by H. zea, feeding on non-Bt refuge plants adjacent to either transgenic Bt or non-Bt plants, were measured to investigate the potential for unintended Bt exposure. Non-Bt plants were infested with H. zea eggs and subplots were destructively sampled twice per week within each treatment to assess larval development, location, and kernel injury. Results indicate that H. zea larval movement between plants is relatively low, ranging from 2-16% of larvae, and occurs mainly after reaching the second instar. Refuge plants in seed mixtures did not produce equivalent numbers of H. zea larvae, kernel injury, and larval development differed as compared with a pure stand of non-Bt plants. This suggests that there may be costs to larvae developing on refuge plants within seed mixtures and additional studies are warranted to define potential impacts. PMID:26318006

  16. Helicoverpa zea (Lepidoptera: Noctuidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) Responses to Sorghum bicolor (Poales: Poaceae) Tissues From Lowered Lignin Lines.

    Science.gov (United States)

    Dowd, Patrick F; Sattler, Scott E

    2015-01-01

    The presence of lignin within biomass impedes the production of liquid fuels. Plants with altered lignin content and composition are more amenable to lignocellulosic conversion to ethanol and other biofuels but may be more susceptible to insect damage where lignin is an important resistance factor. However, reduced lignin lines of switchgrasses still retained insect resistance in prior studies. Therefore, we hypothesized that sorghum lines with lowered lignin content will also retain insect resistance. Sorghum excised leaves and stalk pith Sorghum bicolor (L.) Moench (Poales: Poaceae) from near isogenic brown midrib (bmr) 6 and 12 mutants lines, which have lowered lignin content and increased lignocellulosic ethanol conversion efficiency, were examined for insect resistance relative to wild-type (normal BTx623). Greenhouse and growth chamber grown plant tissues were fed to first-instar larvae of corn earworms, Helicoverpa zea (Boddie) and fall armyworms Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), two sorghum major pests. Younger bmr leaves had significantly greater feeding damage in some assays than wild-type leaves, but older bmr6 leaves generally had significantly less damage than wild-type leaves. Caterpillars feeding on the bmr6 leaves often weighed significantly less than those feeding on wild-type leaves, especially in the S. frugiperda assays. Larvae fed the pith from bmr stalks had significantly higher mortality compared with those larvae fed on wild-type pith, which suggested that bmr pith was more toxic. Thus, reducing lignin content or changing subunit composition of bioenergy grasses does not necessarily increase their susceptibility to insects and may result in increased resistance, which would contribute to sustainable production. PMID:25601946

  17. Next-generation sequencing-based transcriptome analysis of Helicoverpa armigera Larvae immune-primed with Photorhabdus luminescens TT01.

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    Zengyang Zhao

    Full Text Available Although invertebrates are incapable of adaptive immunity, immunal reactions which are functionally similar to the adaptive immunity of vertebrates have been described in many studies of invertebrates including insects. The phenomenon was termed immune priming. In order to understand the molecular mechanism of immune priming, we employed Illumina/Solexa platform to investigate the transcriptional changes of the hemocytes and fat body of Helicoverpa armigera larvae immune-primed with the pathogenic bacteria Photorhabdus luminescens TT01. A total of 43.6 and 65.1 million clean reads with 4.4 and 6.5 gigabase sequence data were obtained from the TT01 (the immune-primed and PBS (non-primed cDNA libraries and assembled into 35,707 all-unigenes (non-redundant transcripts, which has a length varied from 201 to 16,947 bp and a N50 length of 1,997 bp. For 35,707 all-unigenes, 20,438 were functionally annotated and 2,494 were differentially expressed after immune priming. The differentially expressed genes (DEGs are mainly related to immunity, detoxification, development and metabolism of the host insect. Analysis on the annotated immune related DEGs supported a hypothesis that we proposed previously: the immune priming phenomenon observed in H. armigera larvae was achieved by regulation of key innate immune elements. The transcriptome profiling data sets (especially the sequences of 1,022 unannotated DEGs and the clues (such as those on immune-related signal and regulatory pathways obtained from this study will facilitate immune-related novel gene discovery and provide valuable information for further exploring the molecular mechanism of immune priming of invertebrates. All these will increase our understanding of invertebrate immunity which may provide new approaches to control insect pests or prevent epidemic of infectious diseases in economic invertebrates in the future.

  18. Cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae): Large scale rearing and the effect of gamma radiation on selected life history parameters of this pest in China

    International Nuclear Information System (INIS)

    Effective large scale rearing of the cotton bollworm, Helicoverpa armigera (Huebner), has been developed in China. A 'celled unit' system was developed to replace the traditional test tube for cotton bollworm laboratory rearing. Larvae are reared at 26.5 deg. C, ∼ 70% RH, and a long day photoperiod of 14L:10D. Pupae are harvested at about day 20. Percent adult emergence is between 89-93%, and adult females lay an average of 768 eggs. Under this rearing system one generation is completed in 40-42 days and percent pupation is about 66-71%. Mature Helicoverpa armigera female and male pupae were treated with different doses of gamma radiation and out-crossed with untreated mates. Mating ability of both sexes was not affected by radiation. Treated females were highly sterile and laid significantly fewer eggs than untreated controls. Females treated with 300 Gy were completely sterile, while females treated with 250 Gy and 200 Gy still had minimal residual fertility. (author)

  19. New insight to structure-function relationship of GalNAc mediated primary interaction between insecticidal Cry1Ac toxin and HaALP receptor of Helicoverpa armigera.

    Science.gov (United States)

    Sengupta, Anindita; Sarkar, Anindya; Priya, Prerna; Ghosh Dastidar, Shubhra; Das, Sampa

    2013-01-01

    Over the last few decades Cry1Ac toxin has been widely used in controlling the insect attack due to its high specificity towards target insects. The pore-forming toxin undergoes a complex mechanism in the insect midgut involving sequential interaction with specific glycosylated receptors in which terminal GalNAc molecule plays a vital role. Recent studies on Cry toxins interactions with specific receptors revealed the importance of several amino acid residues in domain III of Cry1Ac, namely Q509, N510, R511, Y513 and W545, serve as potential binding sites that surround the putative GalNAc binding pocket and mediate the toxin-receptor interaction. In the present study, alanine substitution mutations were generated in the Cry1Ac domain III region and functional significance of those key residues was monitored by insect bioassay on Helicoverpa armigera larvae. In addition, ligand blot analysis and SPR binding assay was performed to monitor the binding characteristics of Cry1Ac wild type and mutant toxins towards HaALP receptor isolated from Helicoverpa armigera. Mutagenesis data revealed that, alanine substitutions in R511, Y513 and W545 substantially impacted the relative affinity towards HaALP receptor and toxicity toward target insect. Furthermore, in silico study of GalNAc-mediated interaction also confirmed the important roles of these residues. This structural analysis will provide a detail insight for evaluating and engineering new generation Cry toxins to address the problem of change in insect behavioral patterns.

  20. Introgression of Helicoverpa armigera Resistance from Cajanus acutifolius-a Wild Relative from Secondary Gene Pool of Pigeon Pea (Cajanus cajan

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    Deepak R. Jadhav

    2012-07-01

    Full Text Available The aim of the study was to introgress Helicoverpa armigera resistance from wild relative Cajanus acutifolius into pigeonpea, (Cajanus cajan L., an important grain legume in South Asia, East Africa and the West Indies. Pigeonpea grain yields on farmer’s fields are quite low, largely because of damage by insect pests, of which legume pod borer Helicoverpa armigera (Hübner (Lepidoptera: Noctuidae is the important pest worldwide. Pod borer has developed high levels of resistance to chemical insecticides. Currently, there are no cultivars of pigeonpea with high levels of resistance to H. armigera. Therefore, there is a need to identify and introgress resistance genes from the wild relatives of this crop. Wild relative of pigeonpea, Cajanus acutifolius (ICPW 15613 and the interspecific derivatives C. acutifolius x C. cajan have shown resistance to H. armigera. The results showed that all the test lines and C. acutifolius had high levels of flavonoids such as chlorogenic acid, quercetin and rutin in the flowers and buds, which may have resulted in less damage due to H. armigera larvae. Most of the test lines had more than 15.00 g of seed weight (100 seed weight and beige seed color. These lines can be used for pigeonpea improvement for resistance to H. armigera.

  1. Assessment of beneficial role of an insectivorous bird, jungle babbler (Turdoides striatus predation, on Helicoverpa armigera infesting pigeon pea (Cajanus cajan crop Evaluación del rol benéfico de Turdoides striatus como predator de Helicoverpa armigera en el cultivo de guandul (Cajanus cajan

    Directory of Open Access Journals (Sweden)

    Bhavna Bharucha

    2010-04-01

    Full Text Available Jungle babbler (Turdoides striatus, a widely spread sub-tropical insectivorous passerine is considered beneficial to agro-ecosystem, as they devour voraciously on insect matter especially Helicoverpa armigera, the gram pod borer, a notorious pest infesting and causing heavy loses to crops like pigeon pea (Cajanus cajan which is a vital crop of semi-arid tropical and subtropical farming system, providing high quality vegetable protein. Helicoverpa is known to feed on flowers, pods, and seeds and is the most important biotic constraint affecting pigeon pea yields. Jungle babblers have a peculiar foraging style which helps expose the Helicoverpa larvae as well as pupae through various phenological stages of pigeon pea. For comparative assessment of their beneficial role and as a possible bio control agent, in Baroda city (State of Gaujarat, India, was studied, two crops of pigeon pea (insecticide treated and untreated (control were selected. In both treated and control crops, the number of jungle babblers were maximum in pigeon pea fields during october and november in both small pod stage and large pod stage which had heavy infestation of Helicoverpa. Least number of birds was seen during the flowering stage in September. Later in treatment crop three applications of Dunnate and Monocrotophos insecticide spray was done after which the pest population decreased which is reflected in number of birds in the field, while the bird number in control crops grew since insecticide spray was not done and number of larvae increased with the stage of the crop. Along with the main crop pigeon pea, comparative study was also done to see the food preference by these birds in crops like sorghum, maize, cow pea and ploughed and unploughed fields. Maximum number of birds was seen in unploughed field and least in sorghum suggesting that Helicoverpa is preferred food over sorghum grains thus pigeon pea and sorghum can be used as mixed crops to protect the crop from

  2. Effect of emamectin benzoate on mortality, proboscis extension, gustation and reproduction of the corn earworm, Helicoverpa zea.

    Science.gov (United States)

    López, Juan D; Latheef, M A; Hoffmann, W C

    2010-01-01

    Newly emerged corn earworm adults, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) require a carbohydrate source from plant or other exudates and nectars for dispersal and reproduction. Adults actively seek and forage at feeding sites upon eclosion in the habitat of the larval host plant or during dispersal to, or colonization of, a suitable reproductive habitat. This nocturnal behavior of H. zea has potential for exploitation as a pest management strategy for suppression using an adult feeding approach. This approach entails the use of a feeding attractant and stimulant in combination with a toxicant that when ingested by the adult will either reduce fecundity/fertility at sub-lethal dosages or kill the adult. The intent of this study was to assess reproductive inhibition and toxicity of emamectin benzoate on H. zea when ingested by the adults when mixed in ppm active ingredient (wt:vol) with 2.5 M sucrose as a feeding stimulant. Because the mixture has to be ingested to function, the effect of emamectin benzoate was also evaluated at sub-lethal and lethal concentrations on proboscis extension and gustatory response of H. zea in the laboratory. Feral males captured in sex pheromone-baited traps in the field were used for toxicity evaluations because they were readily available and were more representative of the field populations than laboratory-reared adults. Laboratory-reared female moths were used for reproduction effects because it is very difficult to collect newly emerged feral females from the field. Emamectin benzoate was highly toxic to feral H. zea males with LC(50) values (95% CL) being 0.718 (0.532-0.878), 0.525 (0.316-0.751), and 0.182 (0.06-0.294) ppm for 24, 48 and 72 h responses, respectively. Sub-lethal concentrations of emamectin benzoate did not significantly reduce proboscis extension response of feral males and gustatory response of female H. zea. Sublethal concentrations of emamectin benzoate significantly reduced percent larval hatch of

  3. Effects of climate change on overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Huang, Jian; Li, Jing

    2015-07-01

    Climate change significantly affects insects' behaviors. Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most serious insect pests in the world. Much is known about the survival of the overwintering population and spring emergence of H. armigera. However, little is known about the effects of climate change on overwintering and spring emergence of H. armigera. This study investigated the effects of changes of air and soil temperatures and precipitation on overwintering pupae of H. armigera by analyzing historical data from Magaiti County in northwest China using statistical methods. The results showed that during the period of 1989-2006, the climate warming advanced the first-appearance date of overwintering pupae eclosion (FD) and end date of overwintering pupae eclosion (ED) by 1.276 and 0.193 days per year, respectively; the duration between the FD and ED (DFEPE) was prolonged by 1.09 days per year, which resulted in more eclosion of overwintering pupae. For a 1 °C increase in the maximum air temperature ( T max) in winter, the FD became earlier by 3.234 days. Precipitation in winter delayed the FD and ED and produced little relative influence on DFEPE. A 1-mm increase of precipitation in winter delayed the FD and ED by 0.850 and 0.494 days, respectively. Mean air temperature ( T mean) in March, with a 41.3 % relative influence, precipitation in winter, with a 49.0 % relative influence, and T mean in March, with a 37.5 % relative influence, were the major affecting factors on FD, ED, and DFEPE, respectively. T max in February with a 53.0 % relative influence was the major affecting factor on the mortality of overwintering pupae (MOP). Increased soil temperatures in October and November and autumn and air temperatures in winter could decrease the MOP, though the relative influences were lower than T max in February. Increased precipitation in winter increased the MOP, but the relative influence was only 4.2 % because of little precipitation

  4. Gene cloning and expression of cadherin in midgut of Helicoverpa armigera and its Cry1A binding region

    Institute of Scientific and Technical Information of China (English)

    WANG; Guirong; WU; Kongming; LIANG; Gemei; GUO; Yuyuan

    2005-01-01

    Cadherins belong to one of the families of animal glycoproteins responsible for calcium-dependent cell-cell adhesion. Recent literatures showed that the cadherin-like in midgut of several insects served as the receptor of Bt toxin Cry1A and the variation of cadherin-like is related to insect's resistance to Cry1A. The full-length cDNA encoding cadherin-like of Helicoverpa armigera is cloned by degenerate PCR and RACE techniques and the gene was designated as BtR-harm, which is 5581 bp in full-length, encoding 1730 amino acid residues (BtR-harm was deposited in GenBank and the accession number is AF519180). Its predicted molecular weight and isoelectric point were 195.39 kDa and 4.23, respectively. The inferred amino acid sequence includes a signal sequence, 11 cadherin repeats, a membrane-proximal region, a transmembrane region and a cytoplasmic region. Sequence analysis indicated that the deduced protein sequence was most similar to the cadherin-like from Heliothis virescens with 84.2% identity and highly similar to three other lepidopteran cadherin from Bombyx mori, Manduca sexta and Pectinophora gossypiella, with the sequence identities of 60.3.6%, 57.5% and 51.0%, respectively. The cDNA encoding cadherin gene was expressed successfully in E. coli and the recombinant proteins can bind with Cry1Ac. Truncation analysis and binding experiment of BtR-harm revealed that the Cry1A binding region was a contiguous 244-amino acid sequence, which located between amino acid 1217 and 1461. Semi-quantitative RT-PCR analysis showed that BtR-harm was highly expressed in midgut of H. armigera, very low expressed in foregut and hindgut and was not expressed in other tissues. After H. armigera producing resistance to Cry1Ac, the expression quantity of BtR-harm significantly decreased in midgut of H. armigera. It is the first confirmation that BtR-harm can function as receptor of Cry1Ac in H. armigera and the binding region was located on a contiguous 244 amino acid sequence

  5. Gene cloning and expression of cadherin in midgut of Helicoverpa armigera and its Cry1A binding region.

    Science.gov (United States)

    Wang, Guirong; Wu, Kongming; Liang, Gemei; Guo, Yuyuan

    2005-08-01

    Cadherins belong to one of the families of animal glycoproteins responsible for calcium-dependent cell-cell adhesion. Recent literatures showed that the cadherin-like in midgut of several insects served as the receptor of Bt toxin Cry1A and the variation of cadherin-like is related to insect's resistance to Cry1A. The full-length cDNA encoding cadherin-like of Helicoverpa armigera is cloned by degenerate PCR and RACE techniques and the gene was designated as BtR-harm, which is 5581 bp in full-length, encoding 1730 amino acid residues (BtR-harm was deposited in GenBank and the accession number is AF519180). Its predicted molecular weight and isoelectric point were 195.39 kDa and 4.23, respectively. The inferred amino acid sequence includes a signal sequence, 11 cadherin repeats, a membrane-proximal region, a transmembrane region and a cytoplasmic region. Sequence analysis indicated that the deduced protein sequence was most similar to the cadherin-like from Heliothis virescens with 84.2% identity and highly similar to three other lepidopteran cadherin from Bombyx mori, Manduca sexta and Pectinophora gossypiella, with the sequence identities of 60.3.6%, 57.5% and 51.0%, respectively. The cDNA encoding cadherin gene was expressed successfully in E. coli and the recombinant proteins can bind with Cry1Ac. Truncation analysis and binding experiment of BtR-harm revealed that the Cry1A binding region was a contiguous 244-amino acid sequence, which located between amino acid 1217 and 1461. Semi-quantitative RT-PCR analysis showed that BtR-harm was highly expressed in midgut of H. armigera, very low expressed in foregut and hindgut and was not expressed in other tissues. After H. armigera producing resistance to Cry1Ac, the expression quantity of BtR-harm significantly decreased in midgut of H. armigera. It is the first confirmation that BtR-harm can function as receptor of Cry1Ac in H. armigera and the binding region was located on a contiguous 244 amino acid sequence

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

    Institute of Scientific and Technical Information of China (English)

    Alagarmalai Jeyasankar; Selvaraj Premalatha; Kuppusamy Elumalai

    2012-01-01

    Objective:To evaluate the antifeedant, insecticidal and growth inhibition activities of Solanum pseudocapsicum (S. pseudocapsicum) seed extracts against Spodoptera litura (S. litura) and Helicoverpa armigera (H. armigera). Methods:Hexane, diethyl ether, dichloromethane and ethyl acetate seed extracts were prepared and tested for antifeedant, insecticidal and growth inhibitory activities against fourth instar larvae of S. 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.

  7. New insight to structure-function relationship of GalNAc mediated primary interaction between insecticidal Cry1Ac toxin and HaALP receptor of Helicoverpa armigera.

    Directory of Open Access Journals (Sweden)

    Anindita Sengupta

    Full Text Available Over the last few decades Cry1Ac toxin has been widely used in controlling the insect attack due to its high specificity towards target insects. The pore-forming toxin undergoes a complex mechanism in the insect midgut involving sequential interaction with specific glycosylated receptors in which terminal GalNAc molecule plays a vital role. Recent studies on Cry toxins interactions with specific receptors revealed the importance of several amino acid residues in domain III of Cry1Ac, namely Q509, N510, R511, Y513 and W545, serve as potential binding sites that surround the putative GalNAc binding pocket and mediate the toxin-receptor interaction. In the present study, alanine substitution mutations were generated in the Cry1Ac domain III region and functional significance of those key residues was monitored by insect bioassay on Helicoverpa armigera larvae. In addition, ligand blot analysis and SPR binding assay was performed to monitor the binding characteristics of Cry1Ac wild type and mutant toxins towards HaALP receptor isolated from Helicoverpa armigera. Mutagenesis data revealed that, alanine substitutions in R511, Y513 and W545 substantially impacted the relative affinity towards HaALP receptor and toxicity toward target insect. Furthermore, in silico study of GalNAc-mediated interaction also confirmed the important roles of these residues. This structural analysis will provide a detail insight for evaluating and engineering new generation Cry toxins to address the problem of change in insect behavioral patterns.

  8. A Multiplex Real-Time PCR Assay to Diagnose and Separate Helicoverpa armigera and H. zea (Lepidoptera: Noctuidae in the New World.

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    Todd M Gilligan

    Full Text Available The Old World bollworm, Helicoverpa armigera (Hübner, and the corn earworm, H. zea (Boddie, are two of the most important agricultural pests in the world. Diagnosing these two species is difficult-adults can only be separated with a complex dissection, and larvae cannot be identified to species using morphology, necessitating the use of geographic origin for identification in most instances. With the discovery of H. armigera in the New World, identification of immature Helicoverpa based on origin is no longer possible because H. zea also occurs in all of the geographic regions where H. armigera has been discovered. DNA barcoding and restriction fragment length polymorphism (RFLP analyses have been reported in publications to distinguish these species, but these methods both require post-PCR processing (i.e., DNA sequencing or restriction digestion to complete. We report the first real-time PCR assay to distinguish these pests based on two hydrolysis probes that bind to a segment of the internal transcribed spacer region 2 (ITS2 amplified using a single primer pair. One probe targets H. armigera, the second probe targets H. zea, and a third probe that targets a conserved segment of 18S rDNA is used as a control of DNA quality. The assay can be completed in 50 minutes when using isolated DNA and is successfully tested on larvae intercepted at ports of entry and adults captured during domestic surveys. We demonstrate that the assay can be run in triplex with no negative effects on sensitivity, can be run using alternative real-time PCR reagents and instruments, and does not cross react with other New World Heliothinae.

  9. Negative Effects of a Nonhost Proteinase Inhibitor of ~19.8 kDa from Madhuca indica Seeds on Developmental Physiology of Helicoverpa armigera (Hübner

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    Farrukh Jamal

    2014-01-01

    Full Text Available An affinity purified trypsin inhibitor from the seed flour extracts of Madhuca indica (MiTI on denaturing polyacrylamide gel electrophoresis showed that MiTI consisted of a single polypeptide chain with molecular mass of ~19.8 kDa. MiTI inhibited the total proteolytic and trypsin-like activities of the midgut proteinases of Helicoverpa armigera larvae by 87.51% and 76.12%, respectively, at concentration of 5 µg/mL with an IC50 of 1.75 µg/mL against trypsin like midgut proteinases. The enzyme kinetic studies demonstrated that MiTI is a competitive inhibitor with a Ki value of 4.1×10−10 M for Helicoverpa trypsin like midgut proteinases. In vivo experiments with different concentrations of MiTI in artificial diet (0.5, 1.0, and 1.5% w/w showed an effective downfall in the larval body weight and an increase in larval mortality. The concentration of MiTI in the artificial diet to cause 50% mortality (LD50 of larvae was 1.5% w/w and that to cause reduction in mass of larvae by 50% (ED50 was 1.0% w/w. Nutritional indices observations suggest the toxic and adverse effects of MiTI on the growth and development of H. armigera larvae. The results suggest a strong bioinsecticidal potential of affinity purified MiTI which can be exploited in insect pest management of crop plants.

  10. Negative effects of a nonhost proteinase inhibitor of ~19.8 kDa from Madhuca indica seeds on developmental physiology of Helicoverpa armigera (Hübner).

    Science.gov (United States)

    Jamal, Farrukh; Singh, Dushyant; Pandey, Prabhash K

    2014-01-01

    An affinity purified trypsin inhibitor from the seed flour extracts of Madhuca indica (MiTI) on denaturing polyacrylamide gel electrophoresis showed that MiTI consisted of a single polypeptide chain with molecular mass of ~19.8 kDa. MiTI inhibited the total proteolytic and trypsin-like activities of the midgut proteinases of Helicoverpa armigera larvae by 87.51% and 76.12%, respectively, at concentration of 5 µg/mL with an IC50 of 1.75 µg/mL against trypsin like midgut proteinases. The enzyme kinetic studies demonstrated that MiTI is a competitive inhibitor with a K i value of 4.1 × 10(-10) M for Helicoverpa trypsin like midgut proteinases. In vivo experiments with different concentrations of MiTI in artificial diet (0.5, 1.0, and 1.5% w/w) showed an effective downfall in the larval body weight and an increase in larval mortality. The concentration of MiTI in the artificial diet to cause 50% mortality (LD50) of larvae was 1.5% w/w and that to cause reduction in mass of larvae by 50% (ED50) was 1.0% w/w. Nutritional indices observations suggest the toxic and adverse effects of MiTI on the growth and development of H. armigera larvae. The results suggest a strong bioinsecticidal potential of affinity purified MiTI which can be exploited in insect pest management of crop plants. PMID:25298962

  11. Actividad de polvo, extractos y aceite esencial de Peumus boldus Molina solos y en mezcla con Bacillus thuringiensis Berliner contra Spodoptera frugiperda (J.E. Smith) y Helicoverpa zea (Boddie).

    OpenAIRE

    Silva Aguayo, Gonzalo Iván

    2010-01-01

    Se evaluaron en condiciones de laboratorio e invernadero las propiedades insecticidas del polvo, aceite esencial y extracto en cloruro de metileno de Boldo (Peumus boldus Molina), además del alcaloide boldina y el terpeno 1-8-cineol (eucaliptol), solos y en combinación con Bacillus thuringiensis Berliner contra larvas de Spodoptera frugiperda (J.E. Smith) y Helicoverpa zea Boddie. Se realizaron bioensayos para evaluar mortalidad, efecto en el ciclo de vida y las preferencias alimenticias de l...

  12. Bioactivity of a water extract of boldus (Peumus boldus Molina against Spodoptera frugiperda (J.E. Smith and Helicoverpa zea Boddie (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Gonzalo Silva

    2013-06-01

    Full Text Available The insecticidal properties of water-extract of Peumus boldus Molina and its effect on the development cycle and feeding habits of Spodoptera frugiperda J.E. Smith and Helicoverpa zea Boddie were evaluated under laboratory conditions in concentrations of 0.25, 0.5, 1.0, 2.0, 4.0, and 8.0% (w/w. Spodoptera frugiperda was the most susceptible with 75% mortality at 7 d at 8% P. boldus concentration, while H. zea had only 30% mortality. LC50 was 2.31 mL kg-1 for S. frugiperda and 16.05 mL kg¹ for H. zea. When the extract concentration increased in the diet, larval size and weight, percentage of pupation and number of adults decreased, and the time required to reach those states was greater. Neonate larvae fed primarily on the diet with the lower extract concentration and the control was preferred by more than 50% of larvae. Inhibition of feeding, growth, weight gain of 3rd instar larvae as well as new biomass production decreased with concentration of the extract.

  13. A Nonhost Peptidase Inhibitor of ~14 kDa from Butea monosperma (Lam. Taub. Seeds Affects Negatively the Growth and Developmental Physiology of Helicoverpa armigera

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    Prabhash K. Pandey

    2014-01-01

    Full Text Available Helicoverpa armigera is one of the major devastating pests of crop plants. In this context a serine peptidase inhibitor purified from the seeds of Butea monosperma was evaluated for its effect on developmental physiology of H. armigera larvae. B. monosperma peptidase inhibitor on 12% denaturing polyacrylamide gel electrophoresis exhibited a single protein band of ~14 kDa with or without reduction. In vitro studies towards total gut proteolytic enzymes of H. armigera and bovine trypsin indicated measurable inhibitory activity. B. monosperma peptidase inhibitor dose for 50% mortality and weight reduction by 50% were 0.5% w/w and 0.10% w/w, respectively. The IC50 of B. monosperma peptidase inhibitor against total H. armigera gut proteinases activity was 2.0 µg/mL. The larval feeding assays suggested B. monosperma peptidase inhibitor to be toxic as reflected by its retarded growth and development, consequently affecting fertility and fecundity of pest and prolonging the larval-pupal duration of the insect life cycle of H. armigera. Supplementing B. monosperma peptidase inhibitor in artificial diet at 0.1% w/w, both the efficiencies of conversion of ingested as well as digested food were downregulated, whereas approximate digestibility and metabolic cost were enhanced. The efficacy of Butea monosperma peptidase inhibitor against progressive growth and development of H. armigera suggest its usefulness in insect pest management of food crops.

  14. Effects of UV-A exposures on longevity and reproduction in Helicoverpa armigera, and on the development of its F1 generation

    Institute of Scientific and Technical Information of China (English)

    Chang-Yu Zhang; Jian-Yu Meng; Xiao-Ping Wang; Fen Zhu; Chao-Liang Lei

    2011-01-01

    Helicoverpa armigera adults display a conspicuous positive phototacdc behavior to light stimuli,and are especially sensitive to ultraviolet (UV) light.The effects of UV-A (longwave) exposures on adult longevity and reproduction in H.armigera were investigated,as well as the development of the F1 generation.Paired adults were exposed to UV-A for various time periods (0,1,5 and 9 h/day),until the end of adult life.The results showed that adult longevity decreased with increasing exposure time for both sexes,and a significant decrease was observed after exposure for 5 and 9 h/day.Fecundity increased when adults were exposed for 1 and 5 h/day,and a significant difference was observed in the 5 h/day group.Oviposition rates of females in all treatments were significantly higher than in the control.Exposure to UV-A for longer periods (5 and 9 h/day) caused a decline in cumulative survival of F1 immature stages,but no significant differences were found in egg hatch,pupation and eclosion.The developmental periods of F1 larvae were significantly prolonged after exposure to UV-A for 5 and 9 h/day.UV-A radiation had no significant effects on F1 pupal period.

  15. Toxicidade e capacidade de ligação de proteínas Cry1 a receptores intestinais de Helicoverpa armigera (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Isis Sebastião

    2015-11-01

    Full Text Available Resumo: O objetivo deste trabalho foi avaliar a toxicidade e a capacidade de ligação das proteínas Cry1Aa, Cry1Ab, Cry1Ac e Cry1Ca, de Bacillus thuringiensis, a receptores intestinais de Helicoverpa armigera. Realizou-se análise de ligação das proteínas ativadas às vesículas de membrana da microvilosidade apical (VMMA do intestino médio deH. armigera, além de ensaios de competição heteróloga para avaliar sua capacidade de ligação. Cry1Ac destacou-se como a proteína mais tóxica, seguida por Cry1Ab e Cry1Aa. A proteína Cry1Ca não foi tóxica às lagartas e, portanto, não foi possível determinar os seus parâmetros de toxicidade CL50 e CL90. As proteínas Cry1Aa, Cry1Ab e Cry1Ac são capazes de se ligar a um mesmo receptor nas membranas intestinais, o que aumenta o risco do desenvolvimento de resistência cruzada. Portanto, a utilização conjunta dessas proteínas deve ser evitada.

  16. Effects of different brush border membrane vesicle isolation protocols on proteomic analysis of Cry1 Ac binding proteins from the midgut of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    Li-Zhen Chen; Ge-Mei Liang; Brian G.Rector; Jie Zhang; Kong-Ming Wu; Yu-Yuan Guo

    2008-01-01

    Brush border membrane vesicles(BBMV)isolated from insect midguts have been widely used to study CrylA binding proteins.Sample preparation is important in two-dimensional electrophoresis(2-DE),so to determine a suitable BBMV preparation method in Helicoverpa armigera for 2-DE,we compared three published BBMV preparation methods mostly used in sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE).All mctllods yielded similar types and numbers of binding proteins,but in different quantifies.The Abdul.Rauf and Ellar protocol was the best of the three,but had limitations.Sufficient protein qu antity iS important for research involving limited numbers of insects,such as studies of insect resistance to Bacillus thuringiensis in the field.Consequently,we integrated the three BBMV isolation methods into a single protocol that yielded high quantities of BBMV proteins from H.armigera larval midguts.which proved suitable for 2-DE analysis.

  17. Toxicity and binding analyses of Bacillus thuringiensis toxin Vip3A in Cry1Ac-resistant and-susceptible strains of Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qian; CHEN Li-zhen; LU Qiong; ZHANG Yan; LIANG Ge-mei

    2015-01-01

    The Bacil us thuringiensis vegetative insecticidal protein, Vip3A, represents a new family of Bt toxin and is currently ap-plied to commercial transgenic cotton. To determine whether the Cry1Ac-resistant Helicoverpa armigera is cross-resistant to Vip3Aa protein, insecticidal activities, proteolytic activations and binding properties of Vip3Aa toxin were investigated using Cry1Ac-susceptible (96S) and Cry1Ac-resistant H. armigera strain (Cry1Ac-R). The toxicity of Vip3Aa in Cry1Ac-R slightly reduced compared with 96S, the resistance ratio was only 1.7-fold. The digestion rate of ful-length Vip3Aa by gut juice extracts from 96S was little faster than that from Cry1Ac-R. Surface plasmon resonance (SPR) showed there was no signiifcant difference between the binding afifnity of Vip3Aa and BBMVs between 96S and Cry1Ac-R strains, and there was no signiifcant competitive binding between Vip3Aa and Cry1Ac in susceptible or resistant strains. So there had little cross-resistance between Vip3Aa and Cry1Ac,Vip3A+Cry proteins maybe the suitable pyramid strategy to control H. armigera in China in the future.

  18. 早熟素对棉铃虫滞育的终止作用%TERMINATION OF PUPAL DIAPAUSE IN THE BOLLWORM HELICOVERPA ARMIGERA BY PRECOCENE Ⅱ

    Institute of Scientific and Technical Information of China (English)

    王方海; 龚和

    2001-01-01

    用外源激素和某些化合物处理棉铃虫的滞育蛹,结果发现早熟素与蜕皮素-样可终止棉铃虫蛹的滞育,使其进入到发育阶段.而保幼激素类似物ZR-515,环腺氨酸(cAMP)和色氨类化合物(5-HT)则完全不具有终止棉铃虫滞育的作用.结合早熟素还可终止蚜虫寄生蜂Aphidius matricariae Haliday和Praon volucre Haliday的预蛹滞育的报道,建议早熟素应具有终止多种类昆虫滞育的功能.%Precocene Ⅱ terminated pupal diapause in the bollworm Helicoverpa armigera as 20-hydroxyecdysterone did, whereas juvenile hormone analog ZR-515, cyclic adenosine monophosphate (cAMP), and 5-hydroxytryptamine (5-HT) did not. The results indicate that precocene Ⅱ affects diapausing pupae in the similar way as what was found in the prepupae of the aphid parasitoids, Aphidius matricariae Haliday and Praon volucre Haliday (Hymenoptera: Aphidiidae). It is suggested that precocene Ⅱ may affect different kinds of termination of diapause in insects.

  19. Functional validation of cadherin as a receptor of Bt toxin Cry1Ac in Helicoverpa armigera utilizing the CRISPR/Cas9 system.

    Science.gov (United States)

    Wang, Jing; Zhang, Haonan; Wang, Huidong; Zhao, Shan; Zuo, Yayun; Yang, Yihua; Wu, Yidong

    2016-09-01

    Cadherins have been identified as receptors of Bacillus thuringiensis (Bt) Cry1A toxins in several lepidopteran insects including the cotton bollworm, Helicoverpa armigera. Disruption of the cadherin gene HaCad has been genetically linked to resistance to Bt toxin Cry1Ac in H. armigera. By using the CRISPR/Cas9 genome editing system (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9), HaCad from the Cry1Ac-susceptible SCD strain of H. armigera was successfully knocked out. A single positive CRISPR event with a frame shift deletion of 4 nucleotides was identified and made homozygous to create a knockout line named SCD-Cad. Western blotting confirmed that HaCad was no longer expressed in the SCD-Cad line while an intact HaCad of 210 kDa was present in the parental SCD strain. Insecticide bioassays were used to show that SCD-Cad exhibited 549-fold resistance to Cry1Ac compared with SCD, but no significant change in susceptibility to Cry2Ab. Our results not only provide strong reverse genetics evidence for HaCad as a functional receptor of Cry1Ac, but also demonstrate that the CRISPR/Cas9 technique can act as a powerful and efficient genome editing tool to study gene function in a global agricultural pest, H. armigera.

  20. Effect of Artemisia annua L. essential oil on toxicity, enzyme activities, and energy reserves of cotton bollworm Helicoverpa armigera (Hübner (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Mojarab-Mahboubkar Malahat

    2015-12-01

    Full Text Available The essential oil of Artemisia annua L., a weed collected from northern Iran, was studied for its toxicity and physiological aspects on 4th instar larva of the cotton bollworm Helicoverpa armigera Hübner in controlled conditions (26±1°C, 65±10% RH and 16 L : : 8 D h. The artificial diet was used as a medium for investigating the toxicity and the effect of LC10, LC30, LC50, and LC90 on the feeding efficiency of 4th instar larva. The essential oil in doses of LC10, LC30, LC50, and LC90 were estimated to be 2.01%, 3.86%, 6.07%, and 18.34%, respectively. The activity of α-amylase, protease, lipase, general esterases, and glutathione S-transferase and protein, triglyceride, glucose for treated larva were measured. The results showed that all of these parameters were decreased compared with the control. Hence, A. annua essential oil is suggested as a botanical for controlling this important pest of field crops.

  1. Purification of Aminopeptidase N Protein and Differences in cDNAs Encoding APN1 Between Susceptible and Resistant Helicoverpa armigera Strains to Bacillus thuringiensis Toxins

    Institute of Scientific and Technical Information of China (English)

    LIANG Ge-mei; WANG Gui-rong; XU Guang; WU Kong-ming; GUO Yu-yuan

    2004-01-01

    The brush border membrane vesicles (BBMVs) in midgut of Helicoverpa armigera were successfully separated, and most of the Aminopeptidase N (APN) activities in BBMV were preserved. The 3-[(3-chlor-amidopropyl) dimethylammonio]-l-propane-sulphonate (CHAPS)can enhance the dissolution of BBMV, and phosphatidylinositol-specific phosopholipase C (PI-PLC) can cleave the APN from midgut membrane. The APN was primarily purified using a Mono-Q column. The results of immunoblotting showed that the 120 and 170 kDa proteins in the BBMV could bind CrylAc, and 120kDa APN was a glycosylphosphalidylinositol(GPI)anchored protein. Two Bt-resistant strains (Bt-P, Bt-M) were obtained after being selected for more than five years in laboratory using Bt insecticides and Bt transgenic cotton incorporated into diet separately. The resistance of Bt-P and Bt-M were 1 083.3and 48.7 times that of susceptible strain. The genes encoding APN1 in midgut of susceptible and resistant H.armigera were cloned by PCR and RACE techniques. The inferred amino acid sequences of APN1 possessed the common character of APN family in insects. In comparison with APN1 in susceptible strain, three nucleotide mutations were observed in the APN1 of Bt-M strain and resulted in two amino acid replace in the putative protein sequences, and eight nucleotide mutations were observed in Bt-P strain and resulted in five amino acid replace.

  2. Expression of Aminopeptidase N1(APN1),the Main Receptor Protein for Bacillus thuringiensis Cry1A Toxin from Helicoverpa armigera Larval Midgut in Trichoplusia ni cells

    Institute of Scientific and Technical Information of China (English)

    CHANG Hong-lei; LIANG Ge-mei; WANG Gui-rong; YU Hong-kun; GUO Yu-yuan; WU Kong-ming

    2008-01-01

    The aim of this article is to successfully express the Bt(Bacillus thuringiensis)toxin receptor protein located on the internal membrane of larval midgut of cotton bollworm(Helicoverpa armigera Hiibner)within eukaryotic expression system,which is one of the key links for clarifying the relationship between receptor and Bt resistance.The fragments of aminopeptidase N1(APN1)gene without signal peptide in the susceptible and the resistant H. armigera were cloned separately using PCR method,and were separately cloned into pUC 19 vector.After sequencing the gene,the fragments encoding for APN1 without signal peptide were cloned into the Bac-to-Bac baculovirus expression system with transfer vector pFastBacHTB under the polyhedron gene promoter.The recombinant transposing plasmid pFastBacHTB/APN1 was screened and then transformed into Escherichia coli DH10Bac.It was cultured in LB medium,which contained Te, Kan,Ge,X-gal,and IPTG.The resulting recombinant bacmid was transfected into cells of the insect Trichoplusia ni and recombinant baculoviruse was obtained.The lysate of cells infected with recombinant baculoviruse was analyzed by SDS-PAGE and blot analysis.The results showed that the recombinant baculoviruse was fully capable of expressing APN1.The APN1 gene successfully expressed in T. ni cell established the base for continuing the research on its function and relationship of resistance with Bt.

  3. Mitigation of Insecticide Resistance in Helicoverpa armigera (Hubner) (Lepidoptera:Noctuidae) by Conjunctive Use of Trap Crops, Neem and Trichogramma chilonis Ishii in Cotton

    OpenAIRE

    A. Regupathy; P. Duraimurugan

    2005-01-01

    Trichogramma chilonis Ishii was evaluated against cotton bollworm, Helicoverpa armigera (Hubner) under field conditions. Neem seed kernel extract (NSKE) was applied on cotton crop leaving trap crops (okra and pigeonpea) commencing from 46 DAS at weekly interval to increase the pushing of H. armigera away from cotton. Application of NSKE on cotton improved the oviposition preference ratio from 1:1.35 and 1:1.40 to 1:3.02 and 1:2.43 on cotton:okra and cotton:pigeonpea, respectively. Egg parasit...

  4. Evaluación y selección de un protocolo vía Agrobacterium para la incorporación de resistencia al cogollero en la variedad de tomate Unapal-Arreboles Evaluation and selection of a protocol for Agrobacterium-mediated genetic transformation of tomato variety Unapal-Arreboles for resistance to budworm

    Directory of Open Access Journals (Sweden)

    Hernando Ramírez

    2009-04-01

    Full Text Available Se evaluó y seleccionó una metodología para la transformación genética de la variedad de tomate UNAPAL-Arreboles con el gen cry1Ab para la incorporación de resistencia al cogollero (Tuta absoluta, utilizando el sistema de Agrobacterium. Se regeneraron 59 plantas transgénicas a partir de 3.200 explantes (1.84%. La integración estable, expresión y herencia de los genes nptII y gus-intrón, se demostraron mediante análisis histoquímico y molecular en los clones To28, To33 y To47 y en la correspondiente generación T1. Sin embargo, los análisis molecular e inmunológico indicaron ausencia del gen cry1Ab sugiriendo que la secuencia de este gen se puede haber modificado.A plant transformation methodology was selected and evaluated to incorporate the cry1Ab gene by Agrobacterium-mediate genetic transformation into tomato variety UNAPAL-Arreboles for resistance to budworm (Tuta absoluta. A total of 59 transgenic plants were regenerated from 3.200 explants (1.84%. Histochemical gus assay and molecular analysis of three independent events To28, To33 and To47 and corresponding T1 derived generations, demonstrate the stable integration, expression and inheritance of the nptII and gus-intron genes. However, the molecular and immunological analysis of these same clones, indicate that the cry1Ab gene is not present in the transformed plants, suggesting that the sequence of this gene may be modified as result of possible recombinant events.

  5. Purification and Partial Characterization of Trypsin-Specific Proteinase Inhibitors from Pigeonpea Wild Relative Cajanus platycarpus L. (Fabaceae) Active against Gut Proteases of Lepidopteran Pest Helicoverpa armigera.

    Science.gov (United States)

    Swathi, Marri; Mishra, Prashant K; Lokya, Vadthya; Swaroop, Vanka; Mallikarjuna, Nalini; Dutta-Gupta, Aparna; Padmasree, Kollipara

    2016-01-01

    Proteinase inhibitors (PIs) are natural defense proteins of plants found to be active against gut proteases of various insects. A pigeonpea wild relative Cajanus platycarpus was identified as a source of resistance against Helicoverpa armigera, a most devastating pest of several crops including pigeonpea. In the light of earlier studies, trypsin-specific PIs (CpPI 63) were purified from mature dry seeds of C. platycarpus (ICPW-63) and characterized their biochemical properties in contributing to H. armigera resistance. CpPI 63 possessed significant H. armigera gut trypsin-like proteinase inhibitor (HGPI) activity than trypsin inhibitor (TI) activity. Analysis of CpPI 63 using two-dimensional (2-D) electrophoresis and matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry revealed that it contained several isoinhibitors and small oligomers with masses ranging between 6 and 58 kDa. The gelatin activity staining studies suggest that these isoinhibitors and oligomers possessed strong inhibitory activity against H. armigera gut trypsin-like proteases (HGPs). The N-terminal sequence of the isoinhibitors (pI 6.6 and pI 5.6) of CpPI 63 exhibited 80% homology with several Kunitz trypsin inhibitors (KTIs) as well as miraculin-like proteins (MLPs). Further, modification of lysine residue(s) lead to 80% loss in both TI and HGPI activities of CpPI 63. In contrast, the TI and HGPI activities of CpPI 63 were stable over a wide range of temperature and pH conditions. The reported results provide a biochemical basis for pod borer resistance in C. platycarpus. PMID:27656149

  6. Yeast one-hybrid screening the potential regulator of CYP6B6 overexpression of Helicoverpa armigera under 2-tridecanone stress.

    Science.gov (United States)

    Zhao, J; Liu, X N; Li, F; Zhuang, S Z; Huang, L N; Ma, J; Gao, X W

    2016-04-01

    In insect, the cytochrome P450 plays a pivotal role in detoxification to toxic allelochemicals. Helicoverpa armigera can tolerate and survive in 2-tridecanone treatment owing to the CYP6B6 responsive expression, which is controlled by some regulatory DNA sequences and transcription regulators. Therefore, the 2-tridecanone responsive region and transcription regulators of the CYP6B6 are responsible for detoxification of cotton bollworm. In this study, we used yeast one-hybrid to screen two potential transcription regulators of the CYP6B6 from H. armigera that respond to the plant secondary toxicant 2-tridecanone, which were named Prey1 and Prey2, respectively. According to the NCBI database blast, Prey1 is the homology with FK506 binding protein (FKBP) of Manduca sexta and Bombyx mori that belongs to the FKBP-C superfamily, while Prey2 may be a homology of an unknown protein of Papilio or the fcaL24 protein homology of B. mori. The electrophoretic mobility shift assays revealed that the FKBP of prokaryotic expression could specifically bind to the active region of the CYP6B6 promoter. After the 6th instar larvae of H. armigera reared on 2-tridecanone artificial diet, we found there were similar patterns of CYP6B6 and FKBP expression of the cotton bollworm treated with 10 mg g-1 2-tridecanone for 48 h, which correlation coefficient was the highest (0.923). Thus, the FKBP is identified as a strong candidate for regulation of the CYP6B6 expression, when the cotton bollworm is treated with 2-tridecanone. This may lead us to a better understanding of transcriptional mechanism of CYP6B6 and provide very useful information for the pest control. PMID:26696496

  7. High Susceptibility to Cry1Ac and Low Resistance Allele Frequency Reduce the Risk of Resistance of Helicoverpa armigers to Bt Soybean in Brazil.

    Science.gov (United States)

    Dourado, Patrick M; Bacalhau, Fabiana B; Amado, Douglas; Carvalho, Renato A; Martinelli, Samuel; Head, Graham P; Omoto, Celso

    2016-01-01

    The Old World bollworm, Helicoverpa armigera (Hübner), was recently introduced into Brazil, where it has caused extensive damage to cotton and soybean crops. MON 87701 × MON 89788 soybean, which expresses the Bt protein Cry1Ac, was recently deployed in Brazil, providing high levels of control against H. armigera. To assess the risk of resistance to the Cry1Ac protein expressed by MON 87701 × MON 89788 soybean in Brazil, we conducted studies to evaluate the baseline susceptibility of H. armigera to Cry1Ac, in planta efficacy including the assessment of the high-dose criterion, and the initial resistance allele frequency based on an F2 screen. The mean Cry1Ac lethal concentration (LC50) ranged from 0.11 to 1.82 μg·mL-1 of diet among all H. armigera field populations collected from crop seasons 2013/14 to 2014/15, which indicated about 16.5-fold variation. MON 87701 × MON 89788 soybean exhibited a high level of efficacy against H. armigera and most likely met the high dose criterion against this target species in leaf tissue dilution bioassays up to 50 times. A total of 212 F2 family lines of H. armigera were established from field collections sampled from seven locations across Brazil and were screened for the presence of MON 87701 × MON 89788 soybean resistance alleles. None of the 212 families survived on MON 87701 × MON 89788 soybean leaf tissue (estimated allele frequency = 0.0011). The responses of H. armigera to Cry1Ac protein, high susceptibility to MON 87701 × MON 89788 soybean, and low frequency of resistance alleles across the main soybean-producing regions support the assumptions of a high-dose/refuge strategy. However, maintenance of reasonable compliance with the refuge recommendation will be essential to delay the evolution of resistance in H. armigera to MON 87701 × MON 89788 soybean in Brazil. PMID:27532632

  8. Push-pull Strategy with Trap Crops, Neem and Nuclear Polyhedrosis Virus for Insecticide Resistance Management in Helicoverpa armigera (Hubner in Cotton

    Directory of Open Access Journals (Sweden)

    P. Duraimurugan

    2005-01-01

    Full Text Available Insecticide resistance in Helicoverpa armigera (Hubner is a major threat to cotton production in India. The virus infection was found to increase the susceptibility of H. armigera to the insecticides. But, use of Nuclear Polyhedrosis Virus (NPV on a larger scale and on cotton due to leaf alkalinity poses certain practical problems. Hence, studies were carried out to assess the effects of push-pull strategy with trap crops, neem and NPV in cotton for the management of insecticide resistant H. armigera. Field experiments were conducted on cotton (MCU5 with trap crops (okra and pigeonpea and neem was used to diversify the pests to trap crops whereby the control of these pests was assessed with the application of NPV. The preference of H. armigera was towards okra and pigeonpea as a trap crop compared to cotton. Application of NSKE on cotton diversified the H. armigera towards untreated okra and pigeonpea. Push-pull strategy with the conjunctive use of trap crops, restricted application of NSKE on cotton leaving trap crops and restricted application of NPV on trap crops was highly effective in reducing the incidence of H. armigera and damage to fruiting bodies, boll, locule and inter locule basis over cotton sole crop (untreated check. The percent recovery of NPV infected larvae varied from 37.5-47.5, 32.8-39.2 and 14.2-20.2% on okra, pigeon pea and cotton respectively. The synthetic pyrethroids resistance in field survived H. armigera at the end of the season was reduced from 87.5-93.1% to 76.4-84.3%.

  9. Inhibition of Helicoverpa zea (Lepidoptera: Noctuidae) Growth by Transgenic Corn Expressing Bt Toxins and Development of Resistance to Cry1Ab.

    Science.gov (United States)

    Reisig, Dominic D; Reay-Jones, Francis P F

    2015-08-01

    Transgenic corn, Zea mays L., that expresses the Bacillus thuringiensis (Bt) toxin Cry1Ab is only moderately toxic to Helicoverpa zea (Boddie) and has been planted commercially since 1996. Growth and development of H. zea was monitored to determine potential changes in susceptibility to this toxin over time. Small plots of corn hybrids expressing Cry1F, Cry1F × Cry1Ab, Cry1Ab × Cry3Bb1, Cry1A.105 × Cry2Ab2 × Cry3Bb1, Cry1A.105 × Cry2Ab2, and Vip3Aa20 × Cry1Ab × mCry3A were planted in both 2012 and 2013 inNorth and South Carolina with paired non-Bt hybrids from the same genetic background. H. zea larvae were sampled on three time periods from ears and the following factors were measured: kernel area injured (cm(2)) by H. zea larvae, larval number per ear, larval weight, larval length, and larval head width. Pupae were sampled on a single time period and the following factors recorded: number per ear, weight, time to eclosion, and the number that eclosed. There was no reduction in larval weight, number of insect entering the pupal stadium, pupal weight, time to eclosion, and number of pupae able to successfully eclose to adulthood in the hybrid expressing Cry1Ab compared with a non-Bt paired hybrid. As Cry1Ab affected these in 1996, H. zea may be developing resistance to Cry1Ab in corn, although these results are not comprehensive, given the limited sampling period, size, and geography. We also found that the negative impacts on larval growth and development were greater in corn hybrids with pyramided traits compared with single traits.

  10. Determinant Factors in the Production of a Co-Occluded Binary Mixture of Helicoverpa armigera Alphabaculovirus (HearNPV) Genotypes with Desirable Insecticidal Characteristics

    Science.gov (United States)

    Arrizubieta, Maite; Simón, Oihane; Williams, Trevor; Caballero, Primitivo

    2016-01-01

    A co-occluded binary mixture of Helicoverpa armigera nucleopolyhedrovirus genotypes HearSP1B and HearLB6 at a 1:1 ratio (HearSP1B+HearLB6) was selected for the development of a virus-based biological insecticide, which requires an efficient large-scale production system. In vivo production systems require optimization studies in each host-virus pathosystem. In the present study, the effects of larval instar, rearing density, timing of inoculation, inoculum concentration and temperature on the production of HearSP1B+HearLB6 in its homologous host were evaluated. The high prevalence of cannibalism in infected larvae (40–87%) indicated that insects require individual rearing to avoid major losses in OB production. The OB production of recently molted fifth instars (7.0 x 109 OBs/larva), combined with a high prevalence of mortality (85.7%), resulted in the highest overall OB yield (6.0 x 1011 OBs/100 inoculated larvae), compared to those of third or fourth instars. However, as inoculum concentration did not influence final OB yield, the lowest concentration, LC80 (5.5 x 106 OBs/ml), was selected. Incubation temperature did not significantly influence OB yield, although larvae maintained at 30°C died 13 and 34 hours earlier than those incubated at 26°C and 23°C, respectively. We conclude that the efficient production of HearSP1B+HearLB6 OBs involves inoculation of recently molted fifth instars with a LC80 concentration of OBs followed by individual rearing at 30°C. PMID:27732657

  11. Effects of soil temperature and snow cover on the mortality of overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Huang, Jian

    2016-07-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most damaging insect pests in the world. However, little is known about the effects of snow cover and soil temperature on the overwintering pupae of H. armigera. A field experiment was conducted from November 2, 2012 to April 24, 2013 at the agrometeorological experimental station in Wulanwusu, China. Overwintering pupae were embedded into the soil at depths of 5, 10, and 15 cm in the following four treatments: without snow cover, snow cover, and increased temperatures from 600 and 1200 W infrared lights. The results showed that snow cover and rising temperatures could all markedly increase soil temperatures, which was helpful in improving the survival of the overwintering pupae of H. armigera. The mortality of overwintering pupae (MOP) at a depth of 15 cm was the highest, and the MOP at a depth of 5 cm followed. The lower accumulated temperature (≤0 °C) (AT ≤ °C) led to the higher MOP, and the lower diurnal soil temperature range (DSTR) likely led to the lower MOP. After snowmelt, the MOPs at the depths of 5 and 10 cm increased as the soil temperature increased, especially in April. The AT of the soil (≤0 °C) was the factor with the strongest effect on MOP. The soil moisture content was not a major factor affecting the MOP in this semiarid region because precipitation was 45 mm over the entire experimental period. With climate warming, the MOP will likely decrease, and the overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperatures and increased snow cover. PMID:26514355

  12. High Susceptibility to Cry1Ac and Low Resistance Allele Frequency Reduce the Risk of Resistance of Helicoverpa armigera to Bt Soybean in Brazil

    Science.gov (United States)

    Bacalhau, Fabiana B.; Amado, Douglas; Carvalho, Renato A.; Martinelli, Samuel; Head, Graham P.; Omoto, Celso

    2016-01-01

    The Old World bollworm, Helicoverpa armigera (Hübner), was recently introduced into Brazil, where it has caused extensive damage to cotton and soybean crops. MON 87701 × MON 89788 soybean, which expresses the Bt protein Cry1Ac, was recently deployed in Brazil, providing high levels of control against H. armigera. To assess the risk of resistance to the Cry1Ac protein expressed by MON 87701 × MON 89788 soybean in Brazil, we conducted studies to evaluate the baseline susceptibility of H. armigera to Cry1Ac, in planta efficacy including the assessment of the high-dose criterion, and the initial resistance allele frequency based on an F2 screen. The mean Cry1Ac lethal concentration (LC50) ranged from 0.11 to 1.82 μg·mL−1 of diet among all H. armigera field populations collected from crop seasons 2013/14 to 2014/15, which indicated about 16.5-fold variation. MON 87701 × MON 89788 soybean exhibited a high level of efficacy against H. armigera and most likely met the high dose criterion against this target species in leaf tissue dilution bioassays up to 50 times. A total of 212 F2 family lines of H. armigera were established from field collections sampled from seven locations across Brazil and were screened for the presence of MON 87701 × MON 89788 soybean resistance alleles. None of the 212 families survived on MON 87701 × MON 89788 soybean leaf tissue (estimated allele frequency = 0.0011). The responses of H. armigera to Cry1Ac protein, high susceptibility to MON 87701 × MON 89788 soybean, and low frequency of resistance alleles across the main soybean-producing regions support the assumptions of a high-dose/refuge strategy. However, maintenance of reasonable compliance with the refuge recommendation will be essential to delay the evolution of resistance in H. armigera to MON 87701 × MON 89788 soybean in Brazil. PMID:27532632

  13. Characterization and functional analysis ofβ-1,3-galactosyltransferase involved in Cry1Ac resistance from Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-li; LIANG Ge-mei; GAO Xi-wu; CAO Guang-chun; GUO Yu-yuan

    2015-01-01

    Carbohydrate chains are the principal antigens by which Bacil us thuringiensis (Bt) identify receptor proteins. The interaction between the antigen and Bt causes a pore in the membrane of midgut epithelial cel s of insects. Receptor proteins, such as aminopeptidase N and alkaline phosphatase, are glycoproteins. Cadherin is another cel surface receptor protein which has potential glycosylation sites. Glycosyltransferase is very important for the synthesis and modiifcation of receptor proteins. It can indirectly inlfuence the function of Bt. The 1 950 bp ful-length cDNA encodingβ-1,3-galactosyltransferase was cloned from the the midgut of Helicoverpa armigera by degenerative PCR combined with RACE techniques (GAL-Harm, GenBank accession no.:GQ904195.1) with two potential N-glycosylation sites (157NNTI160 and 272NKTL275). Protein sequence alignments revealed that H. armigeraβ-1,3-galactosyltransferase shared high identity withβ-1,3-galactosyltransferase in other insect species. The expression level of theβ-1,3-galactosyltransferase gene in Cry1Ac-resistant H. armigera larvae was 9.2-fold higher than that in susceptible strain. The function ofβ-1,3-galactosyltransferase was investigated using RNAi technique. The result showed Cry1Ac enhanced the toxicity against the siRNA-treated larvae compared with non-siRNA-treated ones, which indicatedβ-1,3-galactosyltransferase played an important role for the insecticidal toxicity of Cry1Ac in H. armigera.

  14. Response of successive three generations of cotton bollworm, Helicoverpa armigera (Hübner), fed on cotton bolls, under elevated CO2

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The growth, development and consumption of successive three generations of cotton bollworm, Helicoverpa armigera (Hübner), fed on cotton bolls grown under elevated CO2 (double-ambient vs. ambient) in open-top chambers were examined. Significant decreases in protein, total amino acid, water and nitrogen content and increases in free fatty acid were observed in cotton bolls. Changes in quality of cotton bolls affected the growth, development and food utilization of H. armigera. Significantly longer larval development duration in three successive generations and lower pupal weight of the second and third generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower fecundity was also found in successive three generations of H. armigera fed on cotton bolls grown under elevated CO2. The consumption per larva occurred significant increase in successive three generations and frass per larva were also significantly increased during the second and third generations under elevated CO2. Significantly lower relative growth rate, efficiency of conversion of ingested food and significant higher relative consumption rate in successive three generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower potential female fecundity, larval numbers and population consumption were found in the second and third generations of cotton bollworm fed on cotton bolls grown under elevated CO2. The integrative effect of higher larval mortality rate and lower adult fecundity resulted in significant decreases in potential population consumption in the latter two generations. The results show that elevated CO2 adversely affects cotton bolls quality, which indicates the potential population dynamics and potential population consumption of cotton bollworm will alleviate the harm to the plants in the future rising CO2 atmosphere.

  15. Cloning and Tissue-Specific Expression of a Chitin Deacetylase Gene from Helicoverpa armigera (Lepidoptera: Noctuidae) and Its Response to Bacillus thuringiensis.

    Science.gov (United States)

    Han, Guoying; Li, Xiumin; Zhang, Ting; Zhu, Xiaoting; Li, Jigang

    2015-01-01

    Chitin deacetylases (CDAs) convert chitin into chitosan, the N-deacetylated form of chitin, which influences the mechanical and permeability properties of structures such as the cuticle and peritrophic matrices. In this article, a new CDA encoding gene, Hacda2, was cloned by reverse transcription-polymerase chain reaction method in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), with an open reading frame of 1,611 bp. The deduced protein composed of 536 amino acid residues with a signal peptide, a chitin-binding domain, a low-density lipoprotein receptor class A domain, and a polysaccharide deacetylase-like catalytic domain. The highest expression level of Hacda2 was detected in fat body among tissues tested in the fifth-instar larvae using real-time quantitative polymerase chain reaction method. Feeding of Bacillus thuringiensis (Bt) (Bacillales: Bacillaceae) diet changed the expression level of Hacda1, Hacda2, Hacda5a, and Hacda5b significantly and differentially in the third-instar larvae. Hacda5a and Hacda5b expression were initially down-regulated and then up-regulated, whereas, the expression level of Hacda1 and Hacda2 was suppressed constantly postfeeding on Bt diet. These results suggested that HaCDAs may be involved in the response of H. armigera larvae to Bt and may be helpful to elucidate the roles of HaCDAs in the action of Bt cry toxin. The potential of HaCDAs to be used as synergists of Bt insecticidal protein needs to be further tested. PMID:26163665

  16. Inhibition of Helicoverpa zea (Lepidoptera: Noctuidae) Growth by Transgenic Corn Expressing Bt Toxins and Development of Resistance to Cry1Ab.

    Science.gov (United States)

    Reisig, Dominic D; Reay-Jones, Francis P F

    2015-08-01

    Transgenic corn, Zea mays L., that expresses the Bacillus thuringiensis (Bt) toxin Cry1Ab is only moderately toxic to Helicoverpa zea (Boddie) and has been planted commercially since 1996. Growth and development of H. zea was monitored to determine potential changes in susceptibility to this toxin over time. Small plots of corn hybrids expressing Cry1F, Cry1F × Cry1Ab, Cry1Ab × Cry3Bb1, Cry1A.105 × Cry2Ab2 × Cry3Bb1, Cry1A.105 × Cry2Ab2, and Vip3Aa20 × Cry1Ab × mCry3A were planted in both 2012 and 2013 inNorth and South Carolina with paired non-Bt hybrids from the same genetic background. H. zea larvae were sampled on three time periods from ears and the following factors were measured: kernel area injured (cm(2)) by H. zea larvae, larval number per ear, larval weight, larval length, and larval head width. Pupae were sampled on a single time period and the following factors recorded: number per ear, weight, time to eclosion, and the number that eclosed. There was no reduction in larval weight, number of insect entering the pupal stadium, pupal weight, time to eclosion, and number of pupae able to successfully eclose to adulthood in the hybrid expressing Cry1Ab compared with a non-Bt paired hybrid. As Cry1Ab affected these in 1996, H. zea may be developing resistance to Cry1Ab in corn, although these results are not comprehensive, given the limited sampling period, size, and geography. We also found that the negative impacts on larval growth and development were greater in corn hybrids with pyramided traits compared with single traits. PMID:26314074

  17. The Impact of Inter-Kernel Movement in the Evolution of Resistance to Dual-Toxin Bt-Corn Varieties in Helicoverpa zea (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Caprio, Michael A; Martinez, Jeannette C; Porter, Patrick A; Bynum, Ed

    2016-02-01

    Seeds or kernels on hybrid plants are primarily F(2) tissue and will segregate for heterozygous alleles present in the parental F(1) hybrids. In the case of plants expressing Bt-toxins, the F(2) tissue in the kernels will express toxins as they would segregate in any F(2) tissue. In the case of plants expressing two unlinked toxins, the kernels on a Bt plant fertilized by another Bt plant would express anywhere from 0 to 2 toxins. Larvae of corn earworm [Helicoverpa zea (Boddie)] feed on a number of kernels during development and would therefore be exposed to local habitats (kernels) that varied in their toxin expression. Three models were developed for plants expressing two Bt-toxins, one where the traits are unlinked, a second where the traits were linked and a third model assuming that maternal traits were expressed in all kernels as well as paternally inherited traits. Results suggest that increasing larval movement rates off of expressing kernels tended to increase durability while increasing movement rates off of nonexpressing kernels always decreased durability. An ideal block refuge (no pollen flow between blocks and refuges) was more durable than a seed blend because the refuge expressed no toxins, while pollen contamination from plants expressing toxins in a seed blend reduced durability. A linked-trait model in an ideal refuge model predicted the longest durability. The results suggest that using a seed-blend strategy for a kernel feeding insect on a hybrid crop could dramatically reduce durability through the loss of refuge due to extensive cross-pollination. PMID:26527792

  18. Laboratory testing and molecular analysis of the resistance of wild and cultivated soybeans to cotton bollworm, Helicoverpa armigera(Hübner)

    Institute of Scientific and Technical Information of China (English)

    Xiaoyi; Wang; Haifeng; Chen; Aihua; Sha; Rong; Zhou; Zhihui; Shang; Xiaojuan; Zhang; Chanjuan; Zhang; Limiao; Chen; Qingnan; Hao; Zhonglu; Yang; Dezhen; Qiu; Shuilian; Chen; Xinan; Zhou

    2015-01-01

    Identifying a superior soybean variety with high defoliator resistance is important to avoid yield loss. Cotton bollworm(Helicoverpa armigera Hübner) is one of the major defoliators of soybean(Glycine max [L.] Merr.) worldwide. In this study, we evaluated the effect of H. armigera larvae on ED059, a wild soybean(Glycine soja Sieb. et Zucc.), and three cultivated soybean varieties: Tianlong 2, PI 535807, and PI 533604, in choice and no-choice assays. The percentage of ED059 leaflets consumed by H. armigera was lower than that of the three cultivated soybeans. Larvae that fed on ED059 exhibited low weight gain and high mortality rate.Waldbauer nutritional indices suggested that ED059 reduced the growth, consumption, and frass production of H. armigera larvae. Larvae that fed on ED059 showed lower efficiency of conversion of ingested and of digested food than those that fed on Tianlong 2 and PI 533604.However, they showed statistically similar consumption index and approximate digestibility compared with those fed on the three cultivated soybeans. Quantitative real-time PCR analysis revealed that 24 h after insect attack, ED059 had higher transcript levels of Kunitz trypsin inhibitor 3, Cysteine proteinase inhibitor 2, and Nerolidol synthase 1 but a lower transcript level of Pathogenesis-related protein 1 than Tianlong 2. The gene expression results were consistent with the presence of higher levels of jasmonic acid(JA) and transcript levels of the JA biosynthesis enzyme allene oxide cyclase 3 in ED059 than in Tianlong 2. Our findings indicate that ED059 is a superior soybean line with strong insect resistance that may be mediated via the JA pathway.

  19. Insecticidal Efficacy of Azadirachta indica, Nucleopolyhedrovirus and Chlorantraniliprole Singly or Combined against Field Populations fo Helicoverpa armigera Hübner (Lepidoptera: Noctuidae Eficacia Insecticida de Azadirachta indica, Nucleopolihedrovirus y Clorantraniliprol solo y sus Aplicaciones Integradas contra Poblaciones de Campo de Helicoverpa armigera Hübner (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Waqas Wakil

    2012-03-01

    Full Text Available The development of resistance in cosmopolitan insect Helicoverpa armigera Hubner (Lepidoptera: Noctuidae forced the researchers for alternative control measures. In the present study, insecticidal efficacy of formulations of Azadirachta indica, a Nucleopolyhedrovirus (NPV, and new anthranilic diamide insecticide (chlorantraniliprole formulations was determined against 2nd, through 5th larval instars of H. armigera collected from diverse geographical locations in the Punjab province, Pakistan. Azadirachta indica was applied at 5 μL L-1; NPV at 2.1 x 10(5 polyhedral occlusion bodies (POB mL4 and chlorantraniliprole at 0.01 μL L-1, either alone or in combinations with each other. The bioassays were conducted at 27 ± 1 °C and 65 ± 5% relative humidity. The mortality varied greatly among treatments, larval instars, and locations. The combinations of NPV with A. indica and chlorantraniliprole caused higher mortality, pupation and produced an additive effect compared to their application singly in all the tested populations. The population from Rawalpindi was always susceptible while the Gujranwala was the resistant. The results herein suggest that the effectiveness of NPV and A. indica can be improved by the presence of chlorantraniliprole against the larvae of H. armigera.Se determinó la eficacia insecticida de formulaciones de Azadirachta indica, Nucleopolihedrovirus (VPN y el nuevo insecticida diamida antranílico (clorantraniliprol en contra de segundo, tercero, cuarto y quinto estadios larvales de Helicoverpa armigera Hubner (Lepidoptera: Noctuidae recogidos de diversas ubicaciones geográficas de la provincia de Punjab, Pakistán. Azadirachta indica se aplicó en dosis de 5 μL L-1; VPN en dosis 2.1 x 10(5 POB mL-1 y clorantraniliprol fue 0,01 μL L-1 ya sea solos o en combinaciones. Los bioensayos se realizaron a 27 ± 1 °C y 65 ± 5% de humedad relativa. La mortalidad fue notablemente variada entre los tratamientos, estadios larvales y

  20. Induction of nicotine in tobacco by herbivory and its relation to glucose oxidase activity in the labial gland of three noctuid caterpillars

    Institute of Scientific and Technical Information of China (English)

    ZONG Na; WANG Chenzhu

    2004-01-01

    Tobacco Nicotiana tabacum L. Is a host plant of Helicoverpa armigera (Hüibner), Helicoverpa assulta Guenée and Spodoptera litura (Fabricius) (Lepidoptera, Noctuidae).The difference in leaf nicotine response to the feeding by these three larvae and the mechanical simulation of their feeding was examined by HPLC. Results indicated that nicotine induction was suppressed by H. Armigera and H. Assulta larvae feeding or by simulated damage treated with their labial glands extracts. The production of nicotine was also suppressed by the glucose oxidase from Aspergillus niger when it was treated on mechanically wounded leaf area. On the contrary, the nicotine production was stimulated by S.litura larva feeding or by simulated damage treated with its labial gland extract. Heat denature can not counteract the stimulation effect of the S. Litura labial gland extracts to tobacco nicotine production. The glucose oxidase activity was detected in labial gland extracts of both H. Arrnigera and H.assulta, but the activity in H. Armigera was significantly higher than that in H. Assulta. No glucose oxidase activity was detected in labial gland extracts of S. Litura. It is shown that the glucose oxidase activity in labial glands of caterpillars plays an important role in the nicotine response to herbivory. The glucose oxidase was mainly contained in the labial gland of H. Armigera larva, and had the highest activity at pH 7.0. D-Glucose was the optimal substrate of the glucose oxidase. Labial gland glucose oxidase activities varied daily during larval development with high activities found when larvae were actively feeding.

  1. Response dynamics of three defense related enzymes in cotton leaves to the interactive stress of Helicoverpa armigera (Hübner) herbivory and omethoate application

    Institute of Scientific and Technical Information of China (English)

    SHA Pin-jie; FAN Yin-jun; WANG Zhi-chao; SHI Xue-yan

    2015-01-01

    In order to explore the response dynamics of the activities of defense related enzymes in cotton leaves towards the inter-active stress of Helicoverpa armigera herbivory and omethoate application, the activities of phenylalanine ammonia-lyase (PAL), lipoxygenase (LOX), and polyphenol oxidase (PPO) were examined from 6 to 126 h after cotton leaves were treated 12 h of H. armigera herbivory, and then sprayed with 800 mg L–1 omethoate. The results showed that the changes in the activities of PAL, LOX and PPO that occured under the interactive stress of H. armigera herbivory and omethoate application relfected the interactive effects of the two stresses on cotton defense. The similarity between the response dynamics of PAL, LOX, and PPO activities in cotton leaves under the interactive stress and that under H. armigera herbivory treatment alone showed that the induction of H. armigera herbivory on the activities of PAL, LOX and PPO in cotton leaves played a leading role in the interactive effects, and the effect of omethoate application played only a minor role. A joint factor analysis was performed according to a method which has been used to analyze the joint toxicity of pesticides;this analysis sought to clarify if there was a synergistic, antagonistic, or additive effect on PAL, LOX, and PPO activity in cotton leaves resulting from the interactive H. armigera herbivory and omethoate treatment. In the interactive effect on the response of PAL activity in cotton leaves, antagonistic effects of the omethoate application towards H. armigera herbivory were observed at 6 and 12 h. Synergistic effects were then observed at 18 and 30 h. Antagonistic effects were observed from 54 to 78 h and syn-ergistic effects were ifnal y observed at 126 h. The correlation between H. armigera herbivory and omethoate application in the interactive effect on cotton defense responses of LOX activity also lfuctuated from synergism to antagonism during the time course. In the interactive

  2. Insecticidal and antifeedant activities of clerodane diterpenoids isolated from the Indian bhant tree, Clerodendron infortunatum, against the cotton bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Abbaszadeh, Gholamreza; Srivastava, Chitra; Walia, Suresh

    2014-01-01

    The Indian bhant tree, Clerodendron infortunatum L. (Lamialus: Lamiaceae), is a well-known medicinal plant, but little information about its bioefficacy against agricultural pests exists. This scarcity was addressed in the present study, in which dried leaves of C. infortunatum were subjected to extraction with hexane and methanol and then partitioned using different solvents of varying polarity. In a preliminary bioassay, the antifeedant effects of the crude extracts and fractions were tested on a highly polyphagous pest, the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), using the no-choice test method with cabbage leaf discs. The methanol fraction resulted in maximum antifeedant activity. This fraction was further subjected to crystallization and column chromatography in order to isolate the compounds responsible for the activity. Three pure compounds were isolated and identified as clerodin (CL), 15-methoxy-14, 15-dihydroclerodin (MD), and 15-hydroxy-14, 15-dihyroclerodin (HD). The antifeedant activity of these compounds was studied using a choice as well as a no-choice test method with 24 and 48 hr observation periods. Insecticidal activity was measured using the topical application method at 0.5, 1, 1.5, 2, 2.5, and 3% concentrations, and data were recorded 24, 48, and 72 hr after treatment. In the no-choice test conditions, compounds CL and MD showed significantly higher antifeedant activity compared to the key ingredient in many commercial pesticides, azadirachtin, at its highest concentration. Compound HD also showed very good antifeedant activity, which did not differ significantly from that of azadirachtin. In the choice test conditions, all three compounds and azadirachtin showed 100% antifeedant activity at the highest concentration. Antifeedant Index (AI50) values of CL, MD, and HD were 6, 6, and 8 ppm in choice tests, and increased to 8, 9, and 11 ppm in the no-choice tests, respectively. Insecticidal activity of the isolated

  3. Pertussis toxin modulation of sodium channels in the central neurons of cyhalothrin-resistant and cyhalothrin-susceptible cotton bollworm, Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    QIANG ZHAO; DE-LING KONG; BING-JUN HE; YAN-QIANG LIU; XIAN-LIN FAN; AN-XI LIU

    2007-01-01

    Pertussis toxin (PTX) inhibits the activation of the α-subunit of the inhibitory heterotrimeric G-proteins (Gαi/o) and modulates voltage-gated sodium channels, which may be one of the primary targets of pyrethroids. To investigate the potential mechanisms of agricultural pests resistance to pyrethroid insecticides, we examined the modulations by PTX on sodium channels in the central neurons of the 3rd-4th instar larvae of cyhalothrin-resistant (Cy-R) and cyhalothrin-susceptible (Cy-S) Helicoverpa armigera by the whole-cell patch-clamp technique.The isolated neurons were cultured for 12-16 h in an improved L15 insect culture medium with or without PTX (400 ng/mL). The results showed that both the Cy-R and Cy-S sodium channels exhibited fast kinetics and tetrodotoxin (TTX) sensitivity. The Cy-R sodium channels exhibited not only altered gating properties, including a 8.88-mV right shift in voltage-dependent activation (V0.5act) and a 6.54-mV right shift in voltage-dependent inactivation (V0.5inact), but also a reduced peak in sodium channel density (Idensity) (55.2% of that in Cy-S neurons). Cy-R sodium channels also showed low excitability, as evidenced by right shift of activation potential (Vacti) by 5-10 mV and peak potential (Vpeak) by 20 mV. PTX exerted significant effects on Cy-S sodium channels,reducing sodium channel density by 70.04%, right shifting V0.5act by 14.41 mV and V0.5inact by 9.38 mV. It did not cause any significant changes of the parameters mentioned above in the Cy-R sodium channels. The activation time (Tpeak) from latency to peak at peak voltage and the fast inactivation time constant (τinact) in both Cy-S and Cy-R neurons were not affected. The results suggest that cotton bollworm resistant to pyrethroid insecticides involves not only mutations and allosteric alterations of voltage-gated sodium channels, but also might implicate perturbation of PTX-sensitive Gαi/o-coupled signaling transduction pathways.

  4. The Binding Characterization of Cry Insecticidal Proteins to the Brush Border Membrane Vesicles of Helicoverpa armigera, Spodoptera exigua, Spodoptera litura and Agrotis ipsilon

    Institute of Scientific and Technical Information of China (English)

    LU Qiong; CAO Guang-chun; ZHANG Li-li; LIANG Ge-mei; GAO Xi-wu; ZHANG Yong-jun; GUO Yu-yuan

    2013-01-01

    Cry toxins produced by Bacillus thuringiensis (Bt) are effective biological insecticides against certain insect species. However, there are potential risks of the evolved resistance of insects to Cry toxin owing to decreased binding of toxins to target sites in the brush border membranes of the larva midgut. The Cry toxins with different binding sites in the larval midgut have been considered to be a good combination to deploy in delaying resistance evolution. Bioassay results demonstrated that the toxicity of different Cry toxins ranked differently for each species. The toxicity ranking was Cry1Ac>Cry1Ab>Cry2Ab for Helicoverpa armigera, Cry1B>Cry1C>Cry2Ab for Spodoptera exigua, and Cry2Ab>Cry1B>Cry1C for S. litura. Only Cry2Ab was toxic to Agrotis ipsilon. Binding experiments were performed with 125I-Cry1Ab, 125I-Cry1Ac, 125I-Cry1B, 125I-Cry1C, 125I-Cry2Ab and the brush border membranes vesicles (BBMV) from H. armigera, S. exigua, S. litura and A. ipsilon. The binding of Cry1Ab and Cry1Ac was shown to be saturable by incubating with increasing concentrations of H. armigera BBMV (Kd=(45.00±2.01) nmol L-1 and (12.80±0.18) nmol L-1, respectively;Bmax=(54.95±1.79) ng and (55.44±0.91) ng, separately). The binding of Cry1B was shown to be saturable by incubating with increasing concentrations of S. exigua BBMV (Kd=(23.26±1.66) nmol L-1;Bmax=(65.37±1.87) ng). The binding of 125I-Cry toxins was shown to be non-saturable by incubating with increasing concentrations of S. litura and A. ipsilon BBMV. In contrast, Cry1B and Cry1C showed some combination with the BBMV of S. litura, and a certain amount of Cry2Ab could bind to the BBMV of A. ipsilon. These observations suggest that a future strategy could be devised for the focused combination of specific cry genes in transgenic crops to control target pests, widen the spectrum of insecticide effectiveness and postpone insect resistance evolution.

  5. Characterization of mechanisms of resistance to common insecticides in noctuid pest species and resistance risk assessment for the new lepidopteran specific compound flubendiamide

    OpenAIRE

    Konanz, Stefanie

    2009-01-01

    Noctuid species, such as the beet armyworm Spodoptera exigua, the cotton bollworm Helicoverpa armigera and the tobacco budworm Heliothis virescens, are well-known pests in many agricultural cropping systems worldwide. The extensive and widespread use of insecticides against these species has led to the development of resistance against almost all commercially used compounds. The focus of this thesis was on the novel lepidopteran specific compound flubendiamde, to get a detailed overview about...

  6. Identification of ABCC2 as a binding protein of Cry1Ac on brush border membrane vesicles from Helicoverpa armigera by an improved pull-down assay.

    Science.gov (United States)

    Zhou, Zishan; Wang, Zeyu; Liu, Yuxiao; Liang, Gemei; Shu, Changlong; Song, Fuping; Zhou, Xueping; Bravo, Alejandra; Soberón, Mario; Zhang, Jie

    2016-08-01

    Cry1Ac toxin-binding proteins from Helicoverpa armigera brush border membrane vesicles were identified by an improved pull-down method that involves coupling Cry1Ac to CNBr agarose combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). According to the LC-MS/MS results, Cry1Ac toxin could bind to six classes of aminopeptidase-N, alkaline phosphatase, cadherin-like protein, ATP-binding cassette transporter subfamily C protein (ABCC2), actin, ATPase, polycalin, and some other proteins not previously characterized as Cry toxin-binding molecules such as dipeptidyl peptidase or carboxyl/choline esterase and some serine proteases. This is the first report that suggests the direct binding of Cry1Ac toxin to ABCC2 in H. armigera. PMID:27037552

  7. Réponse des stades larvaires de Helicoverpa armigera (Hübner (Lepidoptera : Noctuidae à l'application de champignons entomopathogènes Metarhizium anisopliae et Beauveria bassiana

    Directory of Open Access Journals (Sweden)

    Tamò, M.

    2012-01-01

    Full Text Available Response of the nymphs of Helicoverpa armigera (Hübner (Lepidoptera: Noctuidae to entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana. Two experiments on dose/mortality response between the instars of Helicoverpa armigera and two strains of entomopathogenic fungi, Metarhizium anisopliae (Met 31 and Beauveria bassiana (Bb 11 were carried out in laboratory conditions. In the first experiment, M. anisopliae Met 31 was tested on the third instar of H. armigera, while in the second experiment, both Met 31 and Bb 11 were tested on the fourth instar. In all the experiments, the following different doses of conidia per insect were used: 104, 105, 106, 107. The following parameters were measured: mortality and sporulation rates, the number of pupae formed and the number of adults that emerged. Abbott's formula was used to correct the treatment mortality rates. LD50 was determined using Cox-regression. For the third instar in experiment one, no significant difference was observed between high doses (106 and 107 conidia per insect. For instar L4, only the dose of 107 conidia per insect showed high mortality rates (74%. For the strain Bb 11, in spite of the variation observed between the mortality rates induced by high doses (106 and 107 conidia per insect, no significant difference was recorded at the 5% level. No mycosis was observed from cadavers resulting from lower doses when tested on L4. The control recorded the highest numbers of pupae and adults. These two parameters were related to the level of dosage: the higher the dose, the lower the numbers of pupae and adults that emerged. For all the strains of fungi used, whatever the larval stage of H. armigera, the dose/mortality response was significant.

  8. Effects of nuclear polyhedrosis virus on cannibalism in Helicoverpa armigera%核型多角体病毒感染对棉铃虫幼虫同类相残行为的影响

    Institute of Scientific and Technical Information of China (English)

    李静雯; 褚艳娜; 王琼; 刘小侠; 张青文

    2012-01-01

    The effects of nuclear polyhedrosis virus infection on cannibalism in Helicoverpa armigera ( H(u)bner) was evaluated under laborratory conditions. The number of infected larvae preyed on by healthy larvae increased with the progress of the disease. There was no significant difference in the percentage of dead infected larvae, frozen infected larvae and frozen healthy larvae that were preyed on by healthy larvae. This suggests that infected larvae and dead infected larvae are more likely to be cannibalized simply because they become less vigorous and less capable of defending themselves than healthy larvae. There was no significant difference in the frequency of cannibalism of frozen infected larvae by healthy larvae and infected larvae. This suggests that the tendency towards cannibalism is not altered by infection. Cannibalism is potentially costly. The pupation and eclosion rate of healthy larvae that ate infected larvae was lower than that of those that had not cannibalized infected larvae.%在室内研究核型多角体病毒(HaSNPV)感染对棉铃虫Helicoverpa armigera(Hübner)幼虫同类相残行为的影响.结果显示:感病棉铃虫随感病程度的加重,越容易被健康棉铃虫残食,而自然死亡的感病棉铃虫、冻死的感病棉铃虫和冻死的健康棉铃虫三者被健康棉铃虫残食的百分率无显著差异.表明感病棉铃虫和病虫尸体更易于被健康棉铃虫残食,是由于棉铃虫体力减弱而失去反击能力,不是由于病毒本身的影响.以健康棉铃虫、感病棉铃虫为残食者,冻死的病虫为被残食者,相残率无显著差异,表明病毒并未改变棉铃虫残食同类的天性.残食病虫的健康棉铃虫的化蛹率和羽化率均低于正常的健康棉铃虫,残食者为相残行为付出了很高的代价.

  9. Different pairs of male and female of Campoletis chlorideae (Hymenoptera: Ichneumonidae) parasitised the chick pea pod borer, Helicoverpa armigera (Lepidoptera: Noctuidae), in Myanmar

    International Nuclear Information System (INIS)

    In Myanmar, chickpea is of great importance not only for the export but also for local consumption. In 1999-2000, the total area of chickpea was 323,000 acres, with an annual production of 83,000 tons of which 352 metric tons were exported. Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae) is a solitary larval parasitoid that parasitises the larvae of Helicoverpa armigera Huebner (Lepidoptera: Noctuidae) in Myanmar. H. armigera is the major insect pest causing damage to the chickpea crop and significantly reducing yields. The attack of pods seeds varies from 3 to 50%. Conservation of the parasitoid C. chlorideae is important to minimise damage by H. armigera during the reproductive stage of chickpea. Laboratory (potted plants) and field experiments were conducted at the Biological Control Laboratory, Paleik, Singaing Township during the 2002-2003 winter season. Results - Laboratory experiments: The number of C. chlorideae (2 pairs, 3 pairs, 4 pairs and 5 pairs / 30 larvae of H. armigera of 1st stage, 2nd stage, and 3rd stage) significantly and differently affected the survival of different stages of H. armigera larvae (p=0.0001 each R2 = 0.963, C. V 10.98) Replication effects of the experiment were not significant (p=0.1718). Different pairs of C. chlorideae significantly affected the mean survival of larvae H. armigera when the results of four different pairs of parasitoid C. chlorideae were compared (Tukey's studentized range test). The largest difference between the means was observed between 5 pairs and 2 pairs of parasitoids released and the smallest was between 4 and 3 pairs of parasitoids. The results from Tukey's studentised range test showed that 2 pairs of parasitoid C. chlorideae significantly affected the 30 larvae of H. armigera. Different pairs of the parasitoid C. chlorideae also significantly affected the mean parasitism when the results of three different stages of larvae of H. armigera were compared (Tukey's studentised test was used). The

  10. A Conserved Odorant Receptor Tuned to Floral Volatiles in Three Heliothinae Species.

    Directory of Open Access Journals (Sweden)

    Song Cao

    Full Text Available Odorant receptors (ORs play an important role in insects to monitor and adapt to the external environment, such as host plant location, oviposition-site selection, mate recognition and natural enemy avoidance. In our study, we identified and characterized OR12 from three closely-related species, Helicoverpa armigera, Helicoverpa assulta, Heliothis virescens, sharing between 90 and 98% of their amino acids. The tissue expression pattern analysis in H. armigera showed that HarmOR12 was strongly expressed both in male and female antennae, but not in other tissues. Functional analysis performed in the heterologous Xenopus expression system showed that all three OR12 were tuned to six structurally related plant volatiles. Electroantennogram recordings from male and female antennae of H. armigera closely matched the data of in vitro functional studies. Our results revealed that OR12 has a conserved role in Heliothinae moths and might represent a suitable target for the control of these crop pests.

  11. A Conserved Odorant Receptor Tuned to Floral Volatiles in Three Heliothinae Species.

    Science.gov (United States)

    Cao, Song; Liu, Yang; Guo, Mengbo; Wang, Guirong

    2016-01-01

    Odorant receptors (ORs) play an important role in insects to monitor and adapt to the external environment, such as host plant location, oviposition-site selection, mate recognition and natural enemy avoidance. In our study, we identified and characterized OR12 from three closely-related species, Helicoverpa armigera, Helicoverpa assulta, Heliothis virescens, sharing between 90 and 98% of their amino acids. The tissue expression pattern analysis in H. armigera showed that HarmOR12 was strongly expressed both in male and female antennae, but not in other tissues. Functional analysis performed in the heterologous Xenopus expression system showed that all three OR12 were tuned to six structurally related plant volatiles. Electroantennogram recordings from male and female antennae of H. armigera closely matched the data of in vitro functional studies. Our results revealed that OR12 has a conserved role in Heliothinae moths and might represent a suitable target for the control of these crop pests. PMID:27163122

  12. SEQUENCE OF THE 18S RIBOSOMAL RNA GENE OF COTTON BOLLWORM (HELICOVERPA ARMIGERA) AND MOLECULAR SYSTEMATICS ANALYSIS%棉铃虫18S核糖体RNA基因的序列分析及其分子系统学

    Institute of Scientific and Technical Information of China (English)

    王瑛; 陈晓峰; 刘伟; 周红章; 赵珩

    1999-01-01

    克隆并分析了鳞翅目棉铃虫Helicoverpa armigera (Hbner)18S核糖体RNA基因(18S rDNA)的全序列,将该序列与鞘翅目、膜翅目、同翅目、双翅目、捻翅目和弹尾目各一种昆虫的同源保守区进行了比较.序列分析结果显示:鳞翅目和双翅目昆虫在18S rDNA结构上彼此较为相似,捻翅目昆虫的18S rDNA分子结构表现出与其它目昆虫有较大的差异,但相对与弹尾目昆虫的18S rDNA较为接近.该结果支持了有关捻翅目属于一个独立的目级分类阶元的论点.

  13. The pathogenicity of Beauveria bassiana to Helicoverpa armigera under different temperatures and humidities%不同温、湿度下白僵菌对棉铃虫幼虫的致病力

    Institute of Scientific and Technical Information of China (English)

    孙鲁娟; 吴孔明; 郭予元

    2001-01-01

    测试了不同温、湿度下白僵菌Beauveria bassiana对棉铃虫Helicoverpa armigera幼虫的致病力.实验设置了10、15、20、25、30℃5个温度水平,用高浓度(1×108孢子/mL)、中浓度(1×107孢子/mL)、低浓度(1×106孢子/mL)的白僵菌孢子液分别感染1~4龄的棉铃虫.结果表明:三个浓度处理的棉铃虫在温度为25℃时的致死中时(LT50)最短,死亡速度最快,死亡率最高;高于或低于此温度时,棉铃虫的LT50延长,死亡速度减慢.相对湿度发生变化时,感病棉铃虫死亡速度和死亡率明显不同.相对湿度为95%左右时,棉铃虫死亡速度最快,死亡率最高;相对湿度低于70%时,棉铃虫死亡率显著降低.

  14. Identificação morfológica e molecular de Helicoverpa armigera (Lepidoptera: Noctuidae e ampliação de seu registro de ocorrência no Brasil

    Directory of Open Access Journals (Sweden)

    Alexandre Specht

    2013-06-01

    Full Text Available O objetivo deste trabalho foi descrever métodos para a caracterização morfológica e molecular de Helicoverpa armigera e ampliar o registro de ocorrência da praga no Brasil. As mariposas foram obtidas de lagartas coletadas nas culturas de algodão, milho e soja, com uso de armadilhas luminosas. As coletas foram realizadas na Bahia, no Distrito Federal, no Mato Grosso e no Paraná. A identificação foi baseada na genitália masculina e nas análises das sequências dos genes mitocondriais do citocromo B e da região cox1-tRNALeu-cox2. A genitália masculina foi comparada com as descrições morfológicas na literatura, e as sequências de genes, com as depositadas no GenBank. Ambas as análises confirmaram a presença de H. armigera nos locais de coleta. Ampliou-se o registro de ocorrência da praga para a região Sul do país.

  15. 不同光源和暗适应时间对棉铃虫蛾趋光行为的影响%Effects of different light source and dark-adapted time on phototactic behavior of cotton bollworms (Helicoverpa armigera )

    Institute of Scientific and Technical Information of China (English)

    靖湘峰; 罗峰; 朱芬; 黄求应; 雷朝亮

    2005-01-01

    In this paper, the phototactic behaviors of different emergence period Helicoverpa armigera were studied in a phototactic box. The results showed that under the five test wavelength lights, different emergence period female and male moths had no significant difference in their phototactic behaviors. The phototactic rate differed significantly when the dark-adapted time was between 15 and 30 min, but had no significant difference among 30, 45 and 60 min. No significant difference was also found in phototactic rate between dark-adapted time 0 and 15 min under test wavelength lights except green one (500~565 nm).

  16. 天山北坡棉铃虫遗传多样性的RAPD分析%Random Amplified Polymorphic DNA Analysis of the Genetic Diversity of Helicoverpa armigera (Hübner) on the Northern Slope of Tianshan Mountains

    Institute of Scientific and Technical Information of China (English)

    邓菲菲; 王登元; 于江南

    2012-01-01

    [ Objective ] This paper aimed to analyze the genetic diversity of Helicoverpa armigera (Hubner) that came from Urumqi and Fukang on the level of DNA molecule. [Method] 11 RAPD primers were used for analyzing genetic diversity of 5 species of cotton bollworm. [Result]H. armigera had the highest levels of genetic diversity that lived on the 222th farming regiment; H. armigera had high levels of genetic diversity that fed on UYM. The lowest genetic diversity were described in H. armigera fed on CJNG. [ Conclusion ] Relatively high levels of migration and small genetic distance were characterized between H. armigera of corn, piemarker and cotton; compared with that from Fukang, high levels of migration were characterized between H. armigera from Changji and Urumqi.%[目的]对采自乌鲁木齐、三坪农场和阜康222团的棉铃虫从分子水平上进行遗传多样性分析.[方法]利用RAPD( Random Amplified Polymorphic DNA)技术.[结果]筛选出11条引物,并利用这些引物对棉铃虫的5个种群进行遗传分化的研究.222团番茄种群棉铃虫遗传多样性水平最高,乌鲁木齐玉米种群其次,昌吉南瓜种群最低.[结论]玉米、苘麻和棉花三种不同寄主间,棉铃虫基因交流更频繁;同阜康相比,昌吉和乌鲁木齐两个地理位置的棉铃虫更易进行基因交流.

  17. The transmission of sperm in the female reproduction tract of cotton bollworm,Helicoverpa armigera%棉铃虫精子在雌蛾生殖道内的转移动态

    Institute of Scientific and Technical Information of China (English)

    刘绪生; 李国清; 陈长琨

    2001-01-01

    The transmission and distribution of sperm in the reproduction tract of mated female Helicoverpa armigera,were studied with Feulgen smear and microscope count methods.The results were summarized as follows:(1)Both eupyrene and apyrene sperms started their transmission from the spermatophore to spermatheca at 1.5 h after copulation,and finished this process in half hour.Thereafter,the number of sperms in spermatheca decreased gradually;(2)After transferred to spermatheca,the sperms stored in the utriculus in the form of sperm mass.No sperm was found in lagena;(3)Transportation of sperm to the spermatheca was achieved by means of rhythmic muscular contraction of the female reproduction tract.The active apyrene sperm was also believed to assist in the transmission of the eupyrene sperm.%通过显微镜观察、孚尔根涂片法和显微镜计数法研究了棉铃虫精子在雌蛾生殖道内的转移、分布及转移的动力。结果表明:(1)交配结束后1.5 h,雌蛾精包内的真核精子和无核精子开始向受精囊转移,2 h时近2/3的精子已转入受精囊,其后受精囊内精子的数量逐渐下降;(2)精子转移至受精囊后只分布于主囊,成团聚集,副囊中没有精子;(3)雌虫生殖道肌肉的节律性收缩推动精子转移,同时无核精子的运动也有助于真核精子的移动。

  18. 棉铃虫中肠cDNA文库的构建及EST分析%cDNA library construction and EST analysis of the larval midgut of Helicoverpa armnigera ( Lepidoptera: Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    邹朗云; 曹广春; 张谦; 张彦; 梁革梅; 吴孔明; 郭予元

    2011-01-01

    Midgut is the main target for Bacillus thuringiensis (Bt) action, and a number of insect midgut proteins have been proposed as putative Bt toxin receptors. In order to study the resistance mechanism of the cotton bollworm, Helicoverpa armigera to Bt, we constructed a larval midgut cDNA library of the cotton bollworm using the Switching Mechanism at 5' end of the RNA Transcript (SMART)technique.The total RNA of 5th instar larval midgut was extracted and the double-stranded cDNA synthesized. After the normalization treatment, cDNAs were digested and ligated into vector, and then the recombinants were transformed into competent cells. The titer was tested and the cDNA library was amplified and sequenced. The quality evaluation showed that the library had a complexity of 2 × 106 pfu/mL, and the recombination rate was 100%. The average length of inserted cDNA fragments was over 1 000 bp, and 50% fragments were in the full-length form. A total of 1 098 expressed sequence tags (ESTs) were generated successfully after editing and trimming the vector and ambiguous sequences, and 789 unigene sequences were identified, including 132 contigs and 657 singlets. The assembled 789 ESTs were analyzed with Blast in NT, NR and SWISSPORT database of NCBI. The Blast analysis showed that 218 ESTs (27.62%) had no comparable sequences in databases, 119 ESTs (15.08%) had no definite annotations, and the rest 452 ESTs (57.29%) had high homologies with the available sequences, which had definite annotation with over 300 protein products. Through this study, a high-quality cDNA library of the larval midgut of H. armigera has been constructed, which will be a useful tool for studing gene functions in H. armigera midgut.%中肠是苏云金芽孢杆菌Bacillus thuringiensis(Bt)发挥作用的主要部位,中肠上很多蛋白被认为是Bt毒素的结合蛋白.为了探索棉铃虫Helicoverpa armigera对Bt的抗性机制,我们运用RNA转录过程中的5'

  19. 甲氨蝶呤和紫杉醇对棉铃虫繁育能力的影响%Effects of Methotrexate and Paclitaxel on the Ability of Breeding of Cotton Bollworm, Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    马天文; 王俊刚; 何泽敏; 江海澜; 邓小霞; 彭俊

    2012-01-01

    [目的]研究药剂对棉铃虫繁育能力的影响,为安全有效的控制棉铃虫危害奠定理论基础.[方法]采用饲喂法处理棉铃虫成虫,对其产卵量、卵孵化率、实验前后成虫体重差、成虫寿命进行测定.[结果]甲氨蝶呤抑制棉铃虫产卵量效果优于紫杉醇,0.02%甲氨蝶呤处理的棉铃虫单雌产卵量(104粒)最低,比对照降低了72.48%;紫杉醇抑制卵孵化效果好于甲氨蝶呤,0.5%紫杉醇处理的卵孵化率为11.43%,平均校正不育卵率(89.19%)达到最高.甲氨蝶呤处理对雌虫的寿命比对照缩短l~2d.紫杉醇对棉铃虫雄虫有增重作用,而甲氨蝶呤对棉铃虫雌虫有减重作用.[结论]甲氨蝶呤和紫杉醇对棉铃虫繁育能力均有弱化作用,0.02%甲氨蝶呤弱化棉铃虫单雌产卵量效果最好,0.5%紫杉醇抑制卵孵化效果最佳.%[Objective] The purpose of this study was to investigate the effects of agenda on the ability of breeding of cotton bollworm, Helicoverpa armigera (Hübner) in order to lay foundation of controlling the harm of cotton bollworm safely and effectively. [ Method ] Feeding treatment with Methotrexate and Paclitaxel was used to determine the number of eggs laid by per female moth, hatching rate, body weight and lifetime of the adult. [ Result ] The inhibition effect of Methotrexate for laying eggs of cotton bollworm was better than Paclitaxel indoor environment. The number (104 head) of eggs laid by per female moth was the lowest after the treatment using 0.02% Methotrexate, 72.48% reduced than CK, while the inhibition effect of Paclitaxel for hatching rate of eggs was better than Methotrexate. The rate of hatching rate of eggs was 11.43% treated by using 0.5% Paclitaxel,and the revised sterility eggs rates(89. 19%) was the highest. Lifetime of adult moth was reduced by 1 to 2 days in female moths with Methotrexate treatment. Paclitaxel had the function of increasing weight of the male, but Methotrexate

  20. 棉铃虫幼虫中栓锥感器对肌醇和糖类的电生理反应%Responses of medial sensillum of Helicoverpa armigera (Hiibner) (Lepidoptera:Noctuidae) larvae to inositol and sugars

    Institute of Scientific and Technical Information of China (English)

    张雪凝; 汤清波; 蒋金炜; 马英; 胡锡敏; 闫凤鸣

    2011-01-01

    The gustatory electrophysiological responses of medial sensillum of the polyphagous caterpillar, Helicoverpa armigera, to 7 kinds of sugars, inositol and their mixtures were measured by top recording technology. The responding cells in medial sensillum corresponding different stimulus and the interactions of different compounds in mixtures during the process of electrophysiological responses were analyzed. The results showed that: (1) the electrophysiological responses of medial sensillum to D-inositol, D-fructose, xylose, D-arabinose, D-glucose, maltose, D-trehalose and L-rhamnose were obvious, but the responding patterns between sugars and innositol were different trom a concentration-dependent responses in inositol and non-concentration-dependent responseses in sugars; (2) the differences of responding patterns between the pure sugar compounds and the mixture of fructose, arabinose and trehalose were not significant, indicating the same cell responding the 3 kinds of sugars; (3) Responses of the mixtures of fructose and inositol indicated that inositol-sensitive cell responded to fructose. The firing rate of mixture of fructose and inositol were higher than that of the two pure compounds, suggesting the synergistic interaction of responses of the two stimulus. All the results suggested that the inisitol-sensitive cell in medial sensillum of the polyphagous species of H. armigera may be one of “broad-spectrum” taste cells.%利用电生理学技术,以多食性的棉铃虫为研究对象,测定幼虫下颚中栓锥感器对7种糖和肌醇及其混合物的味觉电生理反应,分析不同物质诱导中栓锥感器内对应的味觉感受细胞及不同物质之间诱导昆虫电生理反应的交互作用.结果表明:(1)棉铃虫幼虫下颚中栓锥感器对肌醇、果糖、木糖、阿拉伯糖,葡萄糖、麦芽糖、海藻糖和鼠李糖的单一物质都有明显的电生理反应,但是对肌醇和糖类的反应模式不同,肌醇诱导的反

  1. Cry1Fa对Cry1Ac抗性棉铃虫的毒力评价%Evaluation of the toxicity of Cry1Fa to the Cry1Ac-resistant cotton bollworm,Helicoverpa armigera(Lepidoptera:Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    魏纪珍; 郭予元; 高希武; 张涛; 梁革梅

    2012-01-01

    为了防治多种鳞翅日害虫,表达Cry1 Fa的转基因玉米和棉花已在美国商业化种植.明确棉铃虫Helicoverpa armigera对Cry1Fa与Cry1 Ac的交互抗性及这两种杀虫蛋白之间的协同作用,可以为表达Cry1 Fa+Cry1 Ac的转双价抗虫棉花的合理应用提供依据.本实验测定了Cry1 Fa对棉铃虫敏感品系(96S)及用Cry1Ac筛选的抗性品系(BtR,抗性倍数2194.15倍)的毒力,发现Cry1 Fa对敏感棉铃虫的毒力远低于Cry1 Ac,LC50值是Cry1 Ac的504.80倍;而且抗性品系BtR对Cry1Fa存在19.98倍的交互抗性.Cry1 Fa与Cry1 Ac混用可以提高Cry1 Fa毒杀敏感棉铃虫的效果,尤其是Cry1 Fa浓度较低时,加入Cry1Ac,可以显著增加Cry1 Fa的毒力;但只有加入较高浓度的Cry1 Fa时才能增加Cry1 Ac的毒力.由于BtR品系已经对Cry1 Ac产生抗性,Cry1Ac对抗性棉铃虫的毒力明最降低;在较高浓度的Cry1Ac中加入Cry1 Fa可以显著增加棉铃虫的死亡率(P=0.0015,F=6.88,df=6),但最高死亡率仅为58.33%.D-饱和最优试验的结果证实,Cry1 Ac对于敏感棉铃虫的死亡率的影响达到显著水平(t1=13.76>t0.os),Cry1Ac 与 Cry1Fa的交互作用对毒力的影响也达到显著水平(t22=2.42>t0.05;t11=6.95>t0.05;t12=3.43>t0.05).Cry1Ac和Cry1Fa对抗性棉铃虫死亡率的影响都达到显著水平(t1=3.03>t0.05;t2=2.59>t0.05),但Cry1 Ac是决定抗、感棉铃虫死亡率的关键因素;Cry1Ac与Cry1 Fa最佳浓度配比范围都是1.41~2.10 μg/cm2;在抗性品系中,Cry1 Ac和Cry1 Fa的交互作用不显著.所以,尽管Cry1F+Cry1A作物扩大了杀虫谱,但棉铃虫对这两种蛋白存在交互抗性,而且这两种蛋白混用对治理抗Cry1 Ac棉铃虫的效果不理想,因此不建议在中国种植表达Cry1F+Cry1A的棉花.%Cry 1 Fa-expressing corn and cotton have been commercially planted in U. S in order to effectively control several Lepidoptera pests. Making clear the cross-resistance of cotton bollworms (Helicoverpa armigera

  2. 基于均匀设计与支持向量回归的棉铃虫幼虫全纯人工饲料配方优化%Optimization of chemically defined diet for larvae of the cotton bollworm (Helicoverpa armigera)based on uniform design and support vector regression

    Institute of Scientific and Technical Information of China (English)

    周世豪; 李俊; 姚润贤; 张星; 袁哲明

    2012-01-01

    昆虫全纯人工饲料配方是精细研究昆虫营养生理的前提.本研究以棉铃虫Helicoverpa armigera幼虫为供试对象,以本研究室前期发展的多因素多水平配方优化实验设计与分析方法UD-SVR为指导,以略加修改的苹浅褐卷蛾Epiphyas postvittana幼虫全纯人工饲料为初始配方,先优化20种天然氨基酸,再优化蔗糖等其他8种非氨基酸营养组分,经4轮97个处理组合,获得一个棉铃虫幼虫全纯人工饲料满意配方,平均蛹重、化蛹率分别由初始配方的0.160 g和10.4%高效增至满意配方的0.255 g和97.9%.该全纯人工饲料满意配方的获得,不但再次证实了 UD-SVR方法的有效性,同时为进一步深入研究棉铃虫营养需求与营养代谢奠定了基础.%In order to get a satisfying formula of the chemically artificial diet for larvae of the cotton bollworm, Helicoverpa armigera, we used UD-SVR, an experimental design and analysis method reported by our preliminary studies, for formula optimization. Based on the benchmark diet of a chemically artificial diet for the larvae of the light brown apple moth, Epiphyas postvittana, the contents of 20 natural amino acids were optimized first, and the contents of 8 non-amino acid nutrients including sucrose were optimized then. After 4 rounds of optimization with total 97 schemes, an optimal formula of the chemically artificial diet for the cotton bollworm larvae was obtained. When the H. Armigera larvae fed on this diet, their mean pupal weight and the pupation rate were 0. 255 g and 97. 9% , respectively; when the larvae fed on the benchmark diet, however, the above two indices were only 0. 160 g and 10. 4% ,respectively. The results reconfirmed the effectiveness of UD-SVR in the complex prescription optimization. More importantly, the optimized chemically artificial diet for the cotton bollworm provides the basis for further research on the requirement and metabolism of nutrition compounds in the moth.

  3. 胡椒碱和山椒醇经历对棉铃虫幼虫取食的影响%Effect of Piperine-and Sanshool-Experiences on Larval Feeding of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    李为争; 胡晶晶; 李慧玲; 郭线茹; 闫凤鸣; 原国辉

    2015-01-01

    [Objective]Feeding deterrents or anti-feedants are a broad range of chemicals regulating the feeding behaviour via altering the palatability of crops to herbivores. The idea of pest ecological control using feeding deterrents is an alternative strategy to overcome the negative effect of chemical control. However, almost all insect pests can develop experience-dependent adaptivity to various feeding deterrents, especially gustatory habituation, which limited the practical use of these substances. The objective of this study is to elucidate the sensory organs involved in the feeding deterrence of two amides against a generalist herbivore, Helicoverpa armigera (Hübner), and the effect of prior feeding experience of piperine and sanshool on subsequent feeding behaviour of the larvae, providing a scientific basis for large-scale application.[Method]The olfactory approaching response under dual-choice condition with piperine-and sanshool-treated with tobacco leaf discs was tested, respectively, paired with the control leaf disc, and the feeding duration of the larvae after first encounter with the piperine-or sanshool-treated tobacco leaf discs under non-choice condition was measured. Then the effect of larval feeding experience to piperine and sanshool on their subsequent choice feeding behaviour was tested based on the concentrations at 50%feeding deterrence against the fourth instar larvae.[Result]Piperine and sanshool did not exhibit any repellent effect, and the feeding durations of the larvae after first encounter with piperine-and sanshool-treated tobacco leaf discs were approximately 30 s, significantly shorter than that of the control (longer than 100 s). This feeding duration time was in accordance with the typical post-ingestive response time of a model insect species, Manduca sexta. The concentrations at 50%feeding deterrence to the fourth instar larvae of piperine and sanshool were 0.2259 and 0.4003 mg per tobacco leaf disc (1.5 cm ID), respectively. The

  4. 棉铃虫感染中华卵索线虫后血淋巴游离氨基酸含量的变化%Change in the contents of free amino acids in haemolymph of Helicoverpa armigera infected by Ovomermis sinensis (Nematoda)

    Institute of Scientific and Technical Information of China (English)

    王茂先; 王国秀; 李志强; 李扬; 杨红丽

    2004-01-01

    中华卵索线虫Ovomermis sinens1s感染棉铃虫Helicoverpa armigera l天后,棉铃虫幼虫血淋巴中游离氨基酸总量大幅度下降,各种游离氨基酸的含量也是如此变化.感染2~4天后的棉铃虫血淋巴中游离氨基酸总量变化不大,各种游离氨基酸的含量有升有降.感染5~6天后的棉铃虫血淋巴中游离氨基酸总量和各种氨基酸的含量都急剧上升.研究表明,中华卵索线虫寄生棉铃虫时,棉铃虫血淋巴中游离氨基酸含量的变化朝着有利于线虫生长发育的方向进行.

  5. 棉铃虫中肠氨肽酶 APN4与 Cry1Ac、Cry2Aa 结合能力的比较%Comparison of the binding affinity of the APN4 receptor in Helicoverpa armigera (Hübner) to the Cry1Ac and Cry2Aa insecticidal proteins

    Institute of Scientific and Technical Information of China (English)

    袁向东; 葛朝虹; 肖玉涛; 梁革梅

    2015-01-01

    Objectives] Bt (Bacillus thuringiensis) insecticidal proteins have been widely adopted to control agricultural pests because of their high target specificity. The binding of a Bt insecticidal protein to its specific receptor in the insect midgut plays a key role in the insecticidal action process. Aminopeptidase N (APN) is one of the major Bt protein receptors. To better characterize the molecular mechanism underlying the insecticidal activity of different Bt insecitcidal proteins, and lay the foundation for Bt resistance management and novel Bt insecticidal protein development, we analyzed the binding affinity of aminopeptidase N4 (APN4) to the Cry1Ac and Cry2Aa insecitcidal proteins in Helicoverpa armigera. [Methods] The binding affinity of aminopeptidase N4 (APN4) was assessed using ligand blot analysis and an ELISA binding assay, respectively. [Results] The results show that recombinant APN4 could bind to both Cry1Ac and Cry2A; their respective dissociation constants were 46.7 nmol/L and 26.5 nmol/L. [Conclusion] The results suggest that there was no significant difference in the binding affinity of APN4 to Cry1Ac and Cry2Aa in H. armigera.%【目的】 Bt 杀虫蛋白(Bacillus thuringiensis)具有高度的靶标特异性,已经被广泛用于农业害虫防治。Bt 杀虫蛋白要发挥杀虫活性,必须首先与其受体蛋白结合,氨肽酶 N(Aminopeptidase N)是一类重要的 Bt 受体蛋白。因此,分析该受体与 Bt 杀虫蛋白的结合能力,可为进一步明确不同 Bt 的分子作用机制、Bt 的抗性治理以及新 Bt 的开发应用等提供借鉴。【方法】本文利用 Ligand blot 和 Elisa 方法比较了棉铃虫 Helicoverpa armigera 中肠 APN4(Aminopeptidase N4,APN4)与 Cry1Ac、Cry2Aa 的结合能力。【结果】原核表达的 APN4片段与活化的 Cry1Ac、Cry2Aa 都可以结合,解离常数(Kd)分别是48.59 nmol/L和21.73 nmol/L。【结论】 APN4片段与 Cry1Ac、Cry2Aa 的结合能力

  6. Modes of action of fraxinellone against the tobacco budworm,Heliothis virescens

    Institute of Scientific and Technical Information of China (English)

    Zhi Long Liu; Shuit Hung Ho; Swee Hock Goh

    2009-01-01

    Fraxinellone significantly reduced the relative growth rate, food consumption rate as well as the efficiency of conversion of ingested food into biomass of Heliothis virescens when incorporated into artificial diets at concentrations of 4.31 × 10-5 mol/L and above. After being fed with fraxinellone-treated diets for 24 h, the larval midguts of H. virescens possess significantly lower activities of a-amylase and non-specific proteases and higher activities ofcytochrome P450s. In vitro, the compound did not inhibit the activities of α-amylase and non-specific proteases extracted from the larval midguts. Clear evidence of post-ingestive toxicity of fraxinellone to midgut cells was observed under an electron microscope. The modes of action of the compound against insects were discussed.

  7. 僵蚕提取物对棉铃虫的胃毒作用和碱性磷酸酶活性的影响%Toxicity and Alkaline Phosphatase Activity Inhibition of the Extracts from Bombyx batryticatus Against Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    曹军; 于欢; 张瑞凤; 王沛; 张雅林; 王敦

    2012-01-01

    僵蚕提取物对棉铃虫有胃毒作用,对饲毒后不同时间棉铃虫3龄幼虫体内碱性磷酸酶的活性进行了研究.结果表明,在3龄棉铃虫人工饲料中添加僵蚕提取物浓度为3 mg·g-1时,饲毒第3天试虫的校正死亡率为66.73%;5 mg·g-1的剂量导致试虫死亡率可以高达83.33%,表明僵蚕提取物对棉铃虫具有很强的胃毒作用.试虫碱性磷酸酶活性分析表明,1~5 mg·g-1浓度处理组的试虫碱性磷酸酶活性与对照组相比均显著下降,并有明显的剂量相关性.推测侵蚕对棉铃虫幼虫的毒杀作用机制之一与其对碱性磷酸酶活性的抑制有关.%This paper reported the study results on feeding toxicity and inhibition effects on alkaline phos-phatase (ALP) of Helicoverpa armigera treated with the extracts of Bombyx batryticatus. The corrected mortality of H. armigera treated with the extracts of B. batryticatus at 3 mg · g-1 concentration in insect diet was 66. 7% after feeding on the toxic diet three days, while the corrected mortality was up to 83% to the larvae treated with a concentration of 5 mg · g-1, indicating that the B. batryticatus extracts was high toxic to the third instar larvae of H. armigera. The enzyme assay showed that the ALP activities decreased significantly while treated with the B. batryticatus extracts concentration ranged from 1 mg · g-1 to 5 mg · g-1, and the correlationship was responsible to the dosage of B. batryticatus extracts. Thus, the inhibition on ALP activity is a possible mechanism for the pesticidal activity of B. batryticatus extracts.

  8. The effects of Helicoverpa armigera herbivory on the activity of phenylanlanine ammonialyase, lipoxygenase and polyphenol oxidase in cotton seedling leaves%棉铃虫持续取食对棉花三种防御酶活性的作用

    Institute of Scientific and Technical Information of China (English)

    沙品洁; 亓永凤; 吕超; 李秀霞; 史雪岩; 高希武

    2012-01-01

    Defense-related enzymes of cotton are greatly influenced by various environmental stresses, including insect herbivory. The defense response to insect herbivory plays an important part in the ecological relationship between insects and plants. In order to explore the dynamic interaction between plant defense and Helicoverpa armigera herbivory, the effect of H. Armigera herbivory and the cessation of herbivory on the activity of three defense related enzymes in cotton seedlings was investigated. Changes in the activity of phenylanlanine ammonialyase (PAL), lipoxygenase (LOX) and polyphenol oxidase (PPO) in the leaves of cotton seedlings were measured after these had been fed on by H. Armigera for 2, 6,12, 18 and 24 hours. Changes in PAL, LOX, and PPO activity were measured after removing H. Armigera that had been feeding for 12 hours. The results indicate that the three enzymes responded differently to H. Armigera herbivory. After 2 h and 6 h, PAL activity had not changed significantly but this increased markedly after 12, 18 and 24 h. LOX activity increased significantly after 2, 6, 12, 18 and 24 h, and PPO activity increased after 6 and 24 h. After removing H. Armigera that had been feeding for 12, PAL activity increased until 36 h, whereas LOX activity increased until 24 hthen returned to normal. PPO activity increased only at 12 h and 24 h. There was a positive correlation between changes in PAL, LOX and PPO activity in cotton seeding leaves and the duration of feeding by H. Armigera. The activities of the three defense related enzymes also increased after removing H. Armigera. In contrast, mechanical injury of leaves did not induce change in the activity of the three defense related enzymes comparing to the untreated control. This suggests that the activities of the three defense related enzymes were influenced by insect herbivory, and that this may change the physiological and biochemical properties of cotton leaves.%昆虫取食作为一种关键的生物胁

  9. 低剂量60Co-γ辐射对棉铃虫蛾羽化、寿命、趋光行为和性信息素滴度的影响%Effects of low-dose 60Co-γ radiation on the emergence, longevity,phototactic behavior and sex pheromone titer in Helicoverpa armigera (Lepidoptera: Noctuidae) adults

    Institute of Scientific and Technical Information of China (English)

    闫硕; 朱家林; 张璟; 朱威龙; 张青文; 刘小侠

    2012-01-01

    To illustrate the effects of low-dose 60Co-γ radiation on the development, phototactic behavior and sex pheromone titer in Helicoverpa armigera ( Hübner) , we examined the emergence rate, the deformity rate and longevity of H. armigera adults under five doses of radiation, and determined the rate of phototaxis and sex pheromone titer of H. armigera by phototactic behavior trial and pheromone extraction method. The results indicated that ( 1) there were no effects of 60Co-ü radiation on adult emergence, deformity and longevity of the moth except for the irradiation of 20 Gy, under which the emergence rate was remarkably decreased by 16. 67% ( female) and 20. 00% ( male) , and the deformity rate was increased by 10.00% (both female and male). (2) Both in photophase and scotophase, the rate of phototaxis and sex pheromone titer were increased. The biggest jump of the rate of phototaxis occurred in 3-day-old females in photophase (28. 33%±3. 33% -91. 67% ±4.41% ) , while that of sex pheromone titer occurred in 5-day-old females in scotophase (36. 27 ±4. 26 ng -59. 13 ±4. 63 ng) , indicating that this dose irradiation (50 Gy) probably promoted the occurrence of phototactic behavior and the production of sex pheromone, while the radiation at five doses had no significant effects on phototaxis. (3) There was a declining trend following an increasing trend of the rate of phototaxis and sex pheromone titer as age increased. The biggest jump of the rate of phototaxis occurred in females in photophase and males in scotophase both after radiation (91.67%±4.41% -3.33%±1.67%), while that of sex pheromone titer occurred in females in scotophase after radiation (71. 00 ± 5. 22 ng - 3. 63 ± 1.47 ng). (4) There were no obvious differences in the emergence rate, the deformity rate, longevity and the rate of phototaxis between females and males in most treatments. This research may provide some theoretical basis for exploring the changes in phototaxis and physiological and

  10. 棉铃虫硫氧还蛋白类似基因HaTrx-like的分子鉴定和抗逆特征%Molecular identification of a thioredoxin-like gene in Helicoverpa armigera and its expression following different kinds of stress

    Institute of Scientific and Technical Information of China (English)

    张松斗; 张博宇; 申忠健; 刘彦君; 李贞; 张青文; 刘小侠

    2015-01-01

    【目的】克隆棉铃虫Helicoverpa armigera硫氧还蛋白类似基因(HaTrx-like)的cDNA全长并进行序列分析,研究HaTrx-like基因的时间和空间表达模式以及参与抵抗机械损伤、紫外线照射和极端温度等逆境的特征。【方法】利用RT-PCR的方法扩增得到HaTrx-like基因的全长cDNA并通过测序进行验证,运用几种生物信息学软件对基因和氨基酸序列进行分析,利用荧光定量 PCR 检测 HaTrx-like 基因的时间和空间分布以及4种逆境条件处理后的表达模式。【结果】棉铃虫 HaTrx-like 基因的 cDNA 全长为526 bp,其中开放阅读框长度为381 bp,编码126个氨基酸,含有一个保守的氧化还原活性位点CXXC,其氨基酸序列和帝王斑蝶Danaus plexippus以及家蚕Bombyx mori同源物的序列一致性为72%和71%。HaTrx-like基因在幼虫5龄0 h和5龄96 h,蛹期第1天和第5天,以及成虫第1天的表达量相对较高,在幼虫的中肠、马氏管和成虫的肌肉中的表达量相对较高。在机械损伤、紫外线照射、极端低温和高温处理后,该基因的表达均显著地升高。【讨论】获得了棉铃虫HaTrx-like基因的cDNA全长,并初步鉴定该基因为硫氧还蛋白家族成员,其表达水平受到机械损伤、紫外线照射和极端温度的上调,为进一步深入研究昆虫中硫氧还蛋白家族基因的各种生理功能提供理论基础。%[Objectives] To clone the full-length cDNA of a thioredoxin-like (HaTrx-like) gene in Helicoverpa armigera, to analyze its spatio-temporal distribution in different developmental stages and different tissues, and to determine its expression patterns following mechanical injury, exposure to UV radiation and extreme temperatures. [Methods] The full-length cDNA of HaTrx-like gene was amplified using the RT-PCR method and further validated by sequencing. The gene and protein sequences of HaTrx-like were analyzed with several kinds of

  11. Development of a novel-type transgenic cotton plant for control of cotton bollworm.

    Science.gov (United States)

    Yue, Zhen; Liu, Xiaoguang; Zhou, Zijing; Hou, Guangming; Hua, Jinping; Zhao, Zhangwu

    2016-08-01

    The transgenic Bt cotton plant has been widely planted throughout the world for the control of cotton budworm Helicoverpa armigera (Hubner). However, a shift towards insect tolerance of Bt cotton is now apparent. In this study, the gene encoding neuropeptide F (NPF) was cloned from cotton budworm H. armigera, an important agricultural pest. The npf gene produces two splicing mRNA variants-npf1 and npf2 (with a 120-bp segment inserted into the npf1 sequence). These are predicted to form the mature NPF1 and NPF2 peptides, and they were found to regulate feeding behaviour. Knock down of larval npf with dsNPF in vitro resulted in decreases of food consumption and body weight, and dsNPF also caused a decrease of glycogen and an increase of trehalose. Moreover, we produced transgenic tobacco plants transiently expressing dsNPF and transgenic cotton plants with stably expressed dsNPF. Results showed that H. armigera larvae fed on these transgenic plants or leaves had lower food consumption, body size and body weight compared to controls. These results indicate that NPF is important in the control of feeding of H. armigera and valuable for production of potential transgenic cotton. PMID:26841044

  12. 新疆一枝蒿与黄花蒿粗提物抗棉铃虫与棉蚜的特性研究%The Study on Resistance of Artemisia rupestris and Artemisia annua to Cotton Bollworm ( Helicoverpa armigera ) and Cotton Aphid ( Aphis gossypii )

    Institute of Scientific and Technical Information of China (English)

    何海; 黄丽; 张学涛; 张雷; 李芬; 刘小宁

    2011-01-01

    [ Objective] This research can be a foundation for the development of new pollution - free botanical insecticides. [Method] Two types of coarse solutions from Artemisia rupestris and Artemisia annua were extracted with 97% ethanol, and toxicities of the two extracts to cotton bollworm and cotton aphid were determined, and expellent effect of Artemisia rupestris to laying eggs of cotton bollworms in both the laboratory and the field were also studied. [Result] The results showed: (1) The LC50 of extracts from Artemisia rupestris and Artemisia annua to cotton bollworm are 0 .956 and 2.047 4 g/1OOmL; (2) The LC50 of extracts from Artemisia rupestris and Artemisia annua to cotton aphid are 0.956 and 2.047 4 g/1OOmL; (3) The repellency of extracts of Artemisia rupestris on laying eggs of cotton bollworm in the laboratory and in the field are 28.39% and 80. 68% . [Conclusion] The findings demonstrate that the extracting coarse solutions from Artemisia rupestris are better than that from Artemisia annua as to the killing effect on cotton bollworm and cotton aphid, and it had an expellent effect on laying eggs of cotton bollworms in both the laboratory and the field .%[目的]为利用新疆一枝蒿研制新型无公害植物杀虫药剂奠定基础.[方法]采用97%乙醇对新疆一枝蒿(Artemisia rupestris)和黄花蒿(Artemisia annua)进行了总提,将所得粗提物对棉花重要害虫-棉铃虫(Helicoverpa armigera)与棉蚜(Aphis gossypii)进行了生物活性测定,同时还使用新疆一枝蒿粗提物对棉铃虫开展了室内、室外的驱避实验.[结果](1)新疆一枝蒿与黄花蒿粗提物对棉铃虫半致死浓度LC50分别为3.515 7与4.781 1 mL/100g;(2)新疆一枝蒿与黄花蒿粗提物对棉蚜半致死浓度LC50分别为0.956与2.047 4g/100mL;(3)新疆一枝蒿粗提物对棉铃虫室内室外趋避率分别为28.39%与80.68%.[结论]新疆一枝蒿粗提物对棉铃虫与棉蚜的毒杀作用较好并高于黄花蒿粗提物,且新

  13. Peripheral genetic structure of Helicoverpa zea indicates asymmetrical panmixia

    Science.gov (United States)

    Seasonal climatic shifts create peripheral habitats that alternate between habitable and uninhabitable for migratory species. Such dynamic peripheral habitats are potential sites where migratory species could evolve high genetic diversity resulting from convergence of immigrants from multiple region...

  14. 棉铃虫酯酶两个位点突变对三种杀虫剂代谢活性的影响%Effects of two points mutations of esterases from Helicoverpa armigera on metabolic activities of three kinds of insecticides

    Institute of Scientific and Technical Information of China (English)

    李永强; 安凤秋; 苏立德; 冯俊涛; 张兴

    2012-01-01

    为研究棉铃虫酯酶对有机磷和拟除虫菊酯类杀虫剂的代谢活性,在前期对酯酶001F和001G酶活性研究的基础上,进一步采用荧光法和高效液相色谱法测定了酯酶及其突变体(A127位和F238位突变)对二甲基-4甲基伞形酮磷酸酯(dMUP)、二乙基-7羟基香豆素磷酸酯(dECP)及顺式氰戊菊酯(2.s,d5)的酶促代谢活性。酯酶001F和001G对有机磷的酶促反应常数(kcat值)在2.0×10^-3/min~5.2×10^-3/min之间,后者对顺式氰戊菊酯的代谢活性为10.19μmol·min-1·μmol-1;001F的突变提高了对有机磷的代谢活性,其中001FA127D和001F238L对dMUP的kcat值至少是突变前的2倍;001G的突变却降低了对dECP的代谢活性,但001GF238L对dMUP的活性有所提高。此外,突变体中001F舢。阳对顺式氰戊菊酯的活性与突变前接近,而001G心蹦。则降低到突变前的1/2,其它突变体未检测到活性。结果表明,酯酶001F和001G对杀虫剂有代谢活性,A127位和F238位的突变对酶活性有显著影响。%In order to understand the metabolic activities of esterases in Helicoverpa armigera toward organophosphorus (OPs) and pyrethroid insecticides, the catalytic activities of two esterases (001F and O01G) and their mutants (mutated at positions A127 and F238) toward three kinds of insecticides (i. e., dimethyl- and diethyl- phosphates (dMUP and dECP) and esfenvalerate (2S, aS) ) were measured with iluorometric and HPLC assays. The results showed the enzymatic constants (kcat) of 001F and 001 G for OPs were between 2.0 × 10-3/min and 5.2 ×10-3/min, and 001G also had some metabolic activities toward esfenvalerate (10.19 μmol · min -μmol-1). The mutants of 001 F showed enhanced activities for OPs, the kcat values of both O01FA127D and O01Fr23sL for dMUP (4.5 ×10-3/min and 6.1 ×10 -3/min respectively) were at least 2-fold higher than that of the wild

  15. 新疆北部棉铃虫寄主来源与转基因棉区庇护所评估%Analysis of Larval host types of Cotton Bollworm (Helicoverpa armigera) Populations for Evaluation of Bt Refuges in Northern Xinjiang

    Institute of Scientific and Technical Information of China (English)

    李娜; 张娟; 刘永健; 张豹; 熊建喜; 王佩玲; 吕昭智

    2015-01-01

    Transgenic cotton, expressing an insecticidal toxin from Bacillus thuringiensis (Bt cotton), has been widely cultivated for a long period in some areas of China. Therefore, there is the potential for the cotton bollworm, Helicoverpa armigera, to develop resistance to Bt cotton toxins. The United States Environmental Protection Agency ( US EPA) is rethinking the requirement for some regions to delay developing natural refuge crops where Bt cotton growth has been highly successful. The policy of establishing refuges was intended to delay pest population development of Bt-toxin resistance. Bt cotton is widely grown in Xinjiang Province, which is the largest cotton-producing area in China, but no studies have been conducted on potential refuges in this region of China. In recent years, stable carbon isotope techniques (δ13 C) have been In this study, intelligent forecast light traps were established to collect adult cotton bollworms from May to September 2013, from the 147th and 121st regiments of the Shihezi reclamation area located in northern Xinjiang. The captured moths were placed into bottles and preserved in 95% alcohol until analysis. At each of the sites, 50 males and 30 females moths were selected on the day of capture, their wings combined into two bulked samples respectively to analyze their host type ( C3 or C4 ) using δ13 C analysis. At the same time, 30 female′s wings and corresponding spermatophore were separated to one single sample to analyze the mating type and percentage of mating frequency between C3 and C4 host. A total of 23 bulked samples from the 147th regiment and 25 bulked samples from the 121st regiment were tested. The proportions of C3 and C4 hosts were calculated according to a standard curve constructed in 2012. Approximately 50% of cotton bollworms were derived from C4 hosts, and approximately 50% from C3 hosts in late May and from early August to September. From June to July, 100% of cotton bollworms were derived from C4 hosts. To

  16. 江西省烟田主要害虫及其天敌种群动态%Population Dynamics of the Main Pests and Natural Enemies in Tobacco Fields in Jiangxi Province

    Institute of Scientific and Technical Information of China (English)

    徐昭焕; 罗妹; 喻敏; 张超群; 王建国

    2013-01-01

    通过采用5点调查法,对江西省南昌市烟田主要害虫及其天敌种群数量进行调查并对其进行动态分析。结果显示:烟蚜在烟草整个生长期均有发生,其种群数量动态变化呈双峰曲线,第1个蚜量高峰期出现在6月初,第2个蚜量高峰期出现在6月末至7月初,且蚜量雨后显著降低,雨后高温则又明显增加。烟青虫和斑须蝽在5月初开始发生,其种群数量动态变化均呈单峰曲线。烟青虫虫量高峰期出现在5月末至6月初,斑须蝽虫量高峰期则在6月中旬。烟田内主要天敌有烟蚜茧蜂、蜘蛛类、瓢虫和草蛉。天敌与烟蚜、烟青虫具一定的虫量跟随关系,其中烟蚜茧蜂和草蛉分别在烟草生长前后期与烟蚜跟随关系明显,蜘蛛则在烟青虫发生后与其跟随关系较为明显。%Based on the survey method of five points, we investigated into the population of the pests and natural enemies in tobacco fields in Nanchang, Jiangxi Province, and analyzed their dynamic changes. The experimental results indicated that the population of Myzus persicae had two peaks within a year, the first in early June, and the second from the end of June to early July. Also the population of M. persicae decreased significantly after the rain, and then increased significantly after high temperature. The population of Helicoverpa assulta and Dolycoris baccarum, respectively, had one peak within a year. The peak of H. assulta population occurred from the end of May to early June, and the peak of D. baccarum population occurred in the middle of June. The main natural enemies of the pests in tobacco fields included Aphidius gifuensis, spiders, lacewings and lady beetles. These natural enemies showed synchronization with M. persicae and H. assulta. Of the natural enemies, A. gifuensis and lady beetles, respectively, showed obvious synchronization with M. persicae at the early or later period of the tobacco growth, and

  17. 一株粘质沙雷氏菌对蔬菜常见害虫毒力的研究%Study on the Toxicity of Serratia marcesens to the Common Vegetable Insects

    Institute of Scientific and Technical Information of China (English)

    陈秀为; 范寰; 周可; 兰洪霞; 孙伯芝

    2005-01-01

    从棉田中自然死亡的棉铃虫体上分离得到一株昆虫致病菌,经鉴定为肠杆菌科沙雷氏菌属粘质沙雷氏菌(Serratia marcescens).实验证明该菌对烟青虫(Heliothis assulta)、菜青虫(Pieris rapae)、棉铃虫(Helicoverpa armigera)、小菜蛾(Plutella xylostella)等蔬菜上常见的鳞翅目害虫具有一定的毒力作用.该昆虫致病菌对目标昆虫的毒力主要表现在造成昆虫停食、行动迟缓、对刺激反应迟钝、幼虫生长期缩短、提前化蛹、不能正常羽化等方面.

  18. MASS REARING OF THE ORIENTAL TOBACCO BUDWORM FOR STERILE INSECT TECHNIQUE PROGRAMS%烟青虫人工大量饲养技术的研究

    Institute of Scientific and Technical Information of China (English)

    李咏军; 吴孔明; 罗术东

    2007-01-01

    通过对烟青虫生长发育性状的观察,确定最佳饲料配方和分层多格式的饲养法.结果表明,在添加Vc、番茄酱并调整玉米粉和大豆粉比例为2∶1时,烟青虫的蛹重、每雌虫产卵量和羽化率都有显著提高;分层多个饲养法比单管饲养法蛹重明显提高,养虫效率提高3~5倍,养虫成本降低了4~6倍.本研究的结果为利用昆虫辐射不育技术防治烟青虫提供了技术支持.

  19. Establishment and characterization of insect cell lines from 10 lepidopteran species.

    Science.gov (United States)

    Goodman, C L; El Sayed, G N; McIntosh, A H; Grasela, J J; Stiles, B

    2001-06-01

    Cell lines from selected lepidopteran species were established for the overall purpose of use in baculovirus production. A total of 36 new cell lines from 10 lepidopteran species were generated, including cell lines from a pyralid, the European corn borer, Ostrinia nubilalis, a plutellid, the diamondback moth, Plutella xylostella, as well as eight noctuids: the black cutworm, Agrotis ipsilon, the celery looper, Anagrapha falcifera, the velvetbean caterpillar, Anticarsia gemmatalis, the corn earworm, Helicoverpa zea, the tobacco budworm, Heliothis virescens, the beet armyworm, Spodoptera exigua, the fall armyworm, Spodoptera frugiperda, and the cabbage looper, Trichoplusia ni. Tissues used for cell line establishment included fat bodies, ovaries, testes, or whole embryos/larvae/pupae. All the cell lines were subcultured numerous times, characterized by isoenzyme analysis and/or deoxyribonucleic acid amplification fingerprinting using polymerase chain reaction, and stored in liquid nitrogen. Many of the cell lines were adapted to grow in serum-free medium, with cell lines from A. ipsilon and H. virescens being adapted to suspension culture using shaker flasks. The potential use for these cell lines in baculovirus production is discussed. PMID:11515970

  20. Examination of the biological effects of high anionic peroxidase production in tobacco plants grown under field conditions. I. Insect pest damage.

    Science.gov (United States)

    Dowd, Patrick F; Lagrimini, L Mark

    2006-04-01

    At least 25 wild type and high peroxidase tobacco Nicotiana tabacum L. plants were examined semiweekly over several weeks for pest insect distribution and damage in a 2 year field study. Incidence and/or severity of naturally occurring caterpillar damage (dingy cutworm (Feltia ducens Walker), black cutworm (Agrotis ipsilon (Hufnagel), tobacco hornworm (Manduca sexta L.), and false tobacco budworm (= corn earworm Helicoverpa zea (Boddie)) was significantly reduced at several sample dates for high peroxidase vs. wild type plants. These results parallel those of prior laboratory studies with caterpillars. The number of adult whiteflies (Trialeurodes vaporariorum (Westwood) per plant was significantly reduced on high peroxidase compared to wild type plants on most sample dates in both years. The number of plants with leaves containing >100 aphids (primarily Myzus persicae Sulzer) per leaf on high peroxidase plants was significantly lower that on wild type plants after an equivalent invasion period in both years. A significantly higher proportion of aphids were found dead on leaf five of high peroxidase compared to wild type plants at most sample dates in both years. These results indicate that high peroxidase plants have resistance to a wide range of insects, implicating this enzyme as a broad range resistance mechanism.

  1. Discovery of an unusual biosynthetic origin for circular proteins in legumes.

    Science.gov (United States)

    Poth, Aaron G; Colgrave, Michelle L; Lyons, Russell E; Daly, Norelle L; Craik, David J

    2011-06-21

    Cyclotides are plant-derived proteins that have a unique cyclic cystine knot topology and are remarkably stable. Their natural function is host defense, but they have a diverse range of pharmaceutically important activities, including uterotonic activity and anti-HIV activity, and have also attracted recent interest as templates in drug design. Here we report an unusual biosynthetic origin of a precursor protein of a cyclotide from the butterfly pea, Clitoria ternatea, a representative member of the Fabaceae plant family. Unlike all previously reported cyclotides, the domain corresponding to the mature cyclotide from this Fabaceae plant is embedded within an albumin precursor protein. We confirmed the expression and correct processing of the cyclotide encoded by the Cter M precursor gene transcript following extraction from C. ternatea leaf and sequencing by tandem mass spectrometry. The sequence was verified by direct chemical synthesis and the peptide was found to adopt a classic knotted cyclotide fold as determined by NMR spectroscopy. Seven additional cyclotide sequences were also identified from C. ternatea leaf and flower, five of which were unique. Cter M displayed insecticidal activity against the cotton budworm Helicoverpa armigera and bound to phospholipid membranes, suggesting its activity is modulated by membrane disruption. The Fabaceae is the third largest family of flowering plants and many Fabaceous plants are of huge significance for human nutrition. Knowledge of Fabaceae cyclotide gene transcripts should enable the production of modified cyclotides in crop plants for a variety of agricultural or pharmaceutical applications, including plant-produced designer peptide drugs. PMID:21593408

  2. Ace2, rather than ace1, is the major acetylcholinesterase in the silkworm, Bombyx moil

    Institute of Scientific and Technical Information of China (English)

    Hui-Juan Chen; Zhen Liao; Xiao-Ming Hui; Guo-Qing Li; Fei Li; Zhao-Jun Han

    2009-01-01

    Two acetylcholinesterase (ace) genes have been reported in many insect species. In pests such as Helicoverpa assulta and Plutella xylostellas, acel gene encodes the predominant synaptic enzyme that is the main target of organophosphorus (OP) and carbamate pesticides. It has been reported that pesticide selection has an impact on the ace gene evolution. The domesticated silkworm, Bombyx mori, also has two ace genes. We studied ace gene expression and enzyme activities in silkworm as this has not faced pesticide selection over the past decades. The expression levels of two ace genes, Bm-acel and Bin-ace2, were estimated by quantitative real-time polymerase chain reaction. Bm-ace2 was expressed more highly than Bm-acel in all tested samples of different developmental stages or tissues, suggesting ace2, rather than ace 1, is the major type of acetylcholinesterase (ACHE) in Bombyx mori. This is inconsistent with the aforementioned lepidopterons agricultural pests, partly be due to the widespread use of pesticides that may induce high expression of the acel gene in these pests. Besides high expression in the head, Bm-acel also expresses highly in the silk glands and Bm-ace2 is abundant in the germline, implying both ace genes may have potential non-hydrolytic roles in development. Furthermore, we found that the m_RNA levels of two ace genes and their ratios (ace2/ace1) change day to day in the first and third instars. This challenges the conventional method of estimating enzymatic activity using crude extract as an enzyme solution, as it is a mixture of ACHE1 and ACHE2. An efficient and simple method for separating different ACHEs is necessary for reliable toxicological analyses.

  3. PROTECTION OF SWEET CORN FROM OSTRINIA NUBILALIS HBN. AND HELICOVERPA ARMIGERA HBN.

    Science.gov (United States)

    Vuković, S; Indić, D; Grahovac, M; Franeta, F

    2015-01-01

    O. nubilalis and H. armigera regularly occur and cause significant damages in corn crops in Serbia, particularly under global warming conditions. Several measures are applied against these pests (crop rotation, tolerant and resistant hybrids, monitoring, forecast, chemical measures). Larvae damage stem, panicle and ear, which favour development of saprophytes and secondary infections by mycotoxin producing, pathogenic fungi. The aim of the paper was to test the efficacy of the insecticides azadirachtin and indoxacarb in sweet corn protection against the mentioned pests. The trials were conducted in 2014 at two localities (Becej B. and PoIjanice P.) on sweet corn, hybrid Enterprise according to standard OEPP methods (PP1/13; 1/152; 1/135). Products on the basis of azadirachtin (10 g a.i./I of product) at a rate of 0.4 and 0.5% and indoxacarb (150 g a.i./I of product) at a rate of 0.25 I/ha, were applied. Treatments were conducted on the 5th of August with tractor sprayers (high clearance). The plot size was 5000 m². Three assessments were made. The first one prior to treatment, on 25 randomly selected plants per replicate, and the number of O. nubilalis and H. armigera egg masses and larvae on silk was registered. In the second assessment (18th of August), on 20 randomly selected plants per replicate, the number of damaged plants and the number of vital larvae was registered. In the third assessment, immediately before harvest (28th of August, i.e. 12th of September) on 20 randomly selected plants per replicate, the number of plants broken below ear (fallen on the ground), damaged ears and vital larvae, was determined. Results are presented as means, efficacy (E%) according to Abbott and significance of differences by LSD test (5%). At B locality egg masses of O. nubilalis were registered on ear silk on 13-19% of plants and larvae on 3-7%, and larvae of H. armigera on 2-4%. At P locality egg masses of O. nubilalis were present on 34-40.8% of plants. After 13 days from treatment, at B locality the percentage of damaged plants was 3.8-7.5% and at a significantly lower level compared to control where 40.0% of damaged plants was recorded. Vital larvae of O. nubilalis were present on 1.3-31% of plants, depending on the insecticide and application rate, and in the control on 41.3%. At P locality the percentage of damaged plants per treatment ranged from 20 to 46.3% depending on insecticide and application rate, and in the control 63.8%, and the presence of vital larvae of O. nubilalis on 16.3-21.3% of plants, and in the control on 53.5%. Immediately before harvest, at B locality azadirachtin efficacy, depending on application rate and counted parameters, was 88.5-92.5%; 66.7-72.9% and 69.1-75.2%. Efficacy of indoxacarb in general was 75-100%. At P locality, efficacy of azadirachtin depending on application rate and counted parameters, was 77.8-88.9%; 66.5-83.3% and 44.1-74.6%, while efficacy of this insecticide in general amounted 91.5-100%. PMID:27145581

  4. Histopathological Effects of the Protein Toxin from Xenorhabdus nematophila on the Midgut of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    NANGONG Zi-yan; WANG Qin-ying; SONG Ping; YANG Jun; MAO Wen-jie

    2006-01-01

    Xenorhabdus nematophila HB310, which is highly virulent for many insects, is symbiotic with Steinernema carpocapsae HB310. Toxin Ⅱ was obtained using methods such as salting out and native-PAGE from the cells of X. Nematophila HB310. The histopathology of toxin Ⅱ on H. Armigera larvae was studied by dissecting an olefin slice of the midgut. The symptoms showed that the histopathology of the H. Armigera midgut was similar to that of other novel midgut-active toxins such as the δ-endotoxins from Bacillus thuringiensis, as well as Tca from Photorhabdus luminescens W14. The midgut tissues of H. Armigera fourth-instar larvae began to transform after the oral intake of the toxin Ⅱ over 6 h. First, the anterior region of the peritrophic membrane (PM) began to degrade followed by the elongation of the columnar cells.The epithelium decomposed gradually, and the midgut tissues were either loose or disordered. The PM disappeared after 12 h but reappeared after 72 h following transient or sublethal exposure to the toxin Ⅱ. Toxin Ⅱ also directly destroyed in vitro PMs of H. Armigera.

  5. Function, oligomerization and N-linked glycosylation of the Helicoverpa armigera single nucleopolyhedrovirus envelope fusion protein

    NARCIS (Netherlands)

    Long, G.; Westenberg, M.; Wang, H.; Vlak, J.M.; Hu, Z.

    2006-01-01

    In the family Baculoviridae, two distinct envelope fusion proteins are identified in budded virions (BVs). GP64 is the major envelope fusion protein of group I nucleopolyhedrovirus (NPV) BVs. An unrelated type of envelope fusion protein, named F, is encoded by group II NPVs. The genome of Helicoverp

  6. Comparative Toxicity of Mycotoxins to Navel Orangeworm (Amyelois transitella) and Corn Earworm (Helicoverpa zea)

    Science.gov (United States)

    Mycotoxins, such as aflatoxins and ochratoxins, are widely distributed in nature and are frequently problematic crop contaminants that cause millions of dollars of annual losses in the United States. Insect infestations of crop plants significantly exacerbate mycotoxin contamination. Damage to a v...

  7. Control Efficacy of Dimensional Control Techniques on Main Tobacco Pests%立体防控技术对烤烟主要虫害的防治效果

    Institute of Scientific and Technical Information of China (English)

    蒋水萍; 潘悦; 孙永华; 穆青; 毛春堂

    2014-01-01

    为烤烟生产中虫害的防治提供参考,采用田间试验研究了释放天敌、喷施生物农药、放置诱捕器、杀虫灯等立体防控措施对烤烟烟蚜、烟青虫和斜纹夜蛾三大害虫的防治效果。结果表明:放置黄板、释放异色瓢虫、即时打顶抹杈结合喷施生物农药能将烟蚜的发生量控制在200头/百株以下;释放赤眼蜂配合杀虫灯及喷施低毒生物农药对烟青虫的防治效果平均为55.73%~86.73%,防效比喷施化学农药对照区高15.53~17.90百分点;喷施低毒生物农药、放置诱捕器和杀虫灯,可使斜纹夜蛾在发生高峰期控制在10头/667m2内,发生量比喷施化学农药对照区(18头/667m2)低80%。因此,立体防控措施对烤烟三大虫害的防治效果明显。%In order to provide a reference for pest control on the flue-cured tobacco production,field experiments were carried out to study the three main tobacco pests including Myzus persicae,Helicoverpa assulta and Spodoptera litura controlled by dimensional control techniques such as releasing natural enemy insects,spraying biological pesticides,using pheromone traps and frequency vibrational lamp.The results showed that top pruning timely,inserting yellow board and releasing Harmoniaaxyridis could effectively control the aphid population number,which was under 200 per hundred.Furthermore,H.assulta could be controlled by releasing Trichogramma, using frequency vibrational lamp and spraying biological pesticides,the average efficacy was 86.73%,which was 2.86%~17.90% higher than that of chemical control.S.litura could be controlled within 10 head/667 m2 by spraying biological pesticides,using pheromone traps and frequency vibrational lamp,which was 80% lower than that of chemical control.In all,it indicated that the dimensional control techniques was efficient to the three major tobacco pests.

  8. Optimal Cotton Insecticide Application Termination Timing: A Meta-Analysis.

    Science.gov (United States)

    Griffin, T W; Zapata, S D

    2016-08-01

    The concept of insecticide termination timing is generally accepted among cotton (Gossypium hirsutum) researchers; however, exact timings are often disputed. Specifically, there is uncertainty regarding the last economic insecticide application to control fruit-feeding pests including tarnished plant bug (Lygus lineolaris (Palisot de Beauvois)), boll weevil (Anthonomus grandis), bollworm (Helicoverpa zea), tobacco budworm (Heliothis virescens), and cotton fleahopper (Pseudatomoscelis seriatus). A systematic review of prior studies was conducted within a meta-analytic framework. Nine publicly available articles were amalgamated to develop an optimal timing principle. These prior studies reported 53 independent multiple means comparison field experiments for a total of 247 trial observations. Stochastic plateau theory integrated with econometric meta-analysis methodology was applied to the meta-database to determine the shape of the functional form of both the agronomic optimal insecticide termination timing and corresponding yield potential. Results indicated that current university insecticide termination timing recommendations are later than overall estimated timing suggested. The estimated 159 heat units (HU) after the fifth position above white flower (NAWF5) was found to be statistically different than the 194 HU termination used as the status quo recommended termination timing. Insecticides applied after 159 HU may have been applied in excess, resulting in unnecessary economic and environmental costs. Empirical results also suggested that extending the insecticide termination time by one unit resulted in a cotton lint yield increase of 0.27 kilograms per hectare up to the timing where the plateau began. Based on economic analyses, profit-maximizing producers may cease application as soon as 124 HU after NAWF5. These results provided insights useful to improve production systems by applying inputs only when benefits were expected to be in excess of the

  9. Optimal Cotton Insecticide Application Termination Timing: A Meta-Analysis.

    Science.gov (United States)

    Griffin, T W; Zapata, S D

    2016-08-01

    The concept of insecticide termination timing is generally accepted among cotton (Gossypium hirsutum) researchers; however, exact timings are often disputed. Specifically, there is uncertainty regarding the last economic insecticide application to control fruit-feeding pests including tarnished plant bug (Lygus lineolaris (Palisot de Beauvois)), boll weevil (Anthonomus grandis), bollworm (Helicoverpa zea), tobacco budworm (Heliothis virescens), and cotton fleahopper (Pseudatomoscelis seriatus). A systematic review of prior studies was conducted within a meta-analytic framework. Nine publicly available articles were amalgamated to develop an optimal timing principle. These prior studies reported 53 independent multiple means comparison field experiments for a total of 247 trial observations. Stochastic plateau theory integrated with econometric meta-analysis methodology was applied to the meta-database to determine the shape of the functional form of both the agronomic optimal insecticide termination timing and corresponding yield potential. Results indicated that current university insecticide termination timing recommendations are later than overall estimated timing suggested. The estimated 159 heat units (HU) after the fifth position above white flower (NAWF5) was found to be statistically different than the 194 HU termination used as the status quo recommended termination timing. Insecticides applied after 159 HU may have been applied in excess, resulting in unnecessary economic and environmental costs. Empirical results also suggested that extending the insecticide termination time by one unit resulted in a cotton lint yield increase of 0.27 kilograms per hectare up to the timing where the plateau began. Based on economic analyses, profit-maximizing producers may cease application as soon as 124 HU after NAWF5. These results provided insights useful to improve production systems by applying inputs only when benefits were expected to be in excess of the

  10. Cloning and Sequencing of a Gene Encoding Aminopeptidase N in the Midgut of Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    WANG Gui-rong; LIANG Ge-mei; WU Kong-ming; GUO Yu-yuan

    2003-01-01

    A cDNA encoding aminopeptidase N was cloned by degenerated PCR combined with RACEtechnique in this paper. The full-length of APN-Harm is 3 043 bp. Open reading frame is 2 856 bp inlength, encoding 951 amino acid residues. Its predicted molecular weight and isoelectric point are 108.3kDa and 5.29, respectively. This deduced amino acid sequence shares some common structural features withaminopeptidase N from several moth species, including the consensus zinc-binding motif HEXXHX18 E and the GAMEN motif common to gluzincin aminopeptidases. The first 20 amino acid residues at N-termini ishydrophobic transmembrane helix. The sequence of APN-Harm was deposited in GenBank and the accessionnumber is AY181026.

  11. Cloning and sequence analysis of the cadherin-like protein gene in beet armyworm, Spodoptera exigua%甜菜夜蛾类钙粘蛋白基因全长cDNA的克隆及序列分析

    Institute of Scientific and Technical Information of China (English)

    王玲; 江幸福; 罗礼智; 胡毅; 张蕾

    2012-01-01

    Sesamia inferens, S. nonagrioides, Heliothis virescens and Helicoverpa assulta, with amino acid identity of 61. 28% , 60.34% , 60. 14% and 60. 08% , respectively. These results can provide a basis for revealing the inseetieidal mechanism of Bt in S. exigua, and the resistance mechanism of 5. exigua to Bt.

  12. Highlights of forest pest conditions in the maritimes at the end of July, 1993. Technical note No. 286. Annual publication

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.E.

    1993-01-01

    This note describes forest pest conditions in the Maritimes at the end of July, 1993. It discusses diseases and pests found including forest tent caterpiller, gypsy moth, fall webworm, spruce budworm, and wind damage. Others include eastern blackheaded budworm, elm leafroller, alder flea beetle, birch leafminers, oak olethreutid leafroller, yellowheaded spruce sawfly, and spruce spider mite.

  13. 粘虫类钙粘蛋白基因的克隆、序列分析及时空表达%Cloning, sequence analysis and spatio-temporal expression of cadherin-like protein gene in the oriental armyworm, Mythimna separata (Lepidoptera:Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    王玲; 江幸福; 罗礼智; 胡毅; 张蕾

    2011-01-01

    The cadherin-like proteins, located in the brush border membrane vesicles ( BBMV) of insect midgut, are major receptors of Bacillus thuringiensis insecticidal crystal protein. The complete cDNA sequence of cadherin-like protein gene was amplified from the oriental armyworm, Mythimna separata, using RT-PCR and RACE techniques. The full cDNA sequence (named as Msclp, GenBank accession no. JF951432) is 5 642 bp in length, encoding 1 757 amino acid residues, and the deduced amino acid sequence shows typical characteristics of the known insect cadherin proteins, including a signal peptide, a proprotein region, twelve cadherin repeats, a membrane-proximal region, a transmembrane region and a cytoplasmic region. The predicted molecular mass and isoelectric point are 196. 786 kD and 4. 5, respectively. The cadherin-like protein from M. Separata shows the close relationship to cadherin proteins from Helicoverpa assulta, Heliothis virescens, Helicoverpa armigera and Spodoptera exigua, with the amino acid identities of 61.77% , 61.66% , 61.26% and 58. 14% , respectively. The real-time RT-PCR results showed that relative expression levels of cadherin-like gene were significantly different in different instars of larvae (P < 0. 01) , which was the highest in the 4th instar larvae and the lowest in the newly-hatched larvae. The cadherin-like gene was majorly expressed in the midgut and very lowly expressed in other parts of the larval body. The results provide the basis for revealing the insecticidal mechanism of Bt to oriental armyworm, and the resistance mechanism of oriental armyworm to Bt.%昆虫中肠膜类钙粘蛋白( cadherin-like protein,CLP)是苏云金芽孢杆菌Bacillus thuringiensis (Bt)毒素的重要受体之一,与Bt毒素的杀虫作用机制以及昆虫对Bt毒素的抗性等密切相关.本研究应用RT-PCR和RACE技术,克隆了迁飞性重要害虫粘虫Mythimna separata类钙粘蛋白基因全长cDNA序列(命名为Msclp,GenBank登录号为JF951432),

  14. Effect of pyramiding Bt and CpTI genes on resistance of cotton to Helicoverpa armigera (Lepidoptera: Noctuidae) under laboratory and field conditions

    NARCIS (Netherlands)

    Cui, J.J.; Luo, J.Y.; Werf, van der W.; Ma, Y.; Xia, J.Y.

    2011-01-01

    Transgenic cotton (Gossypium hirsutum L.) varieties, adapted to China, have been bred that express two genes for resistance to insects. the Cry1Ac gene from Bacillus thuringiensis (Berliner) (Bt), and a trypsin inhibitor gene from cowpea (CpTI). Effectiveness of the double gene modification in confe

  15. Response of the digestive system of Helicoverpa zea to ingestion of potato carboxypeptidase inhibitor and characterization of an uninhibited carboxypepidase B

    NARCIS (Netherlands)

    Bayes, A.; Rodrigues de la Vega, M.; Vendrell, J.; Aviles, F.X.; Jongsma, M.A.; Beekwilder, M.J.

    2006-01-01

    Carboxypeptidase activity participates in the protein digestion process in the gut of lepidopteran insects, supplying free amino-acids to developing larvae. To study the role of different carboxypeptidases in lepidopteran protein digestion, the effect of potato carboxypeptidase inhibitor (PCI) on th

  16. Tissue-specific expression of glutathione S-transferases induced by 2-tridecanone or quercetin in cotton bollworms, Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    TANG Fang; LIANG Pei; GAO Xiwu

    2005-01-01

    The tissue-specific expression of glutathione S-transferases (GSTs) in the cotton bollworm and the expression level induced by 2-tridecanone and quercetin were examined using the methods of biochemistry and the quantitative PCR. The relative expression level of GST mRNA was unanimous with the GSTs activity conjugaging with 1-chloro-2, 4-dimitro-benzene (CDNB) in fat bodies,midguts, heads and integuments of cotton bollworms. The GSTs activity in fat bodies was the highest, then midguts, heads and integuments in turn, which was in consistent with the relative expression level of GST mRNA. The specific activity of GSTs and the relative expression level of GST mRNA could be significantly induced by 2-tridecanone and quercetin, and after the induction the order of the GSTs activity and the relative expression level of GST mRNA in the above four tissues in cotton bollworms was not different from the control.The induction of GSTs by 2-tridecanone was stronger than by quercetin in all four tissues, which was in accordance with the relative expression level of GST mRNA. It suggested that the increase of GSTs activity induced by plant allelochemicals was associated with the elevated expression of GST mRNA in cotton bollworms.

  17. Characterization of the resistance to Vip3Aa in Helicoverpa armigera from Australia and the role of midgut processing and receptor binding

    OpenAIRE

    Maissa Chakroun; Núria Banyuls; Tom Walsh; Sharon Downes; Bill James; Juan Ferré

    2016-01-01

    Crops expressing genes from Bacillus thuringiensis (Bt crops) are among the most successful technologies developed for the control of pests but the evolution of resistance to them remains a challenge. Insect resistant cotton and maize expressing the Bt Vip3Aa protein were recently commercialized, though not yet in Australia. We found that, although relatively high, the frequency of alleles for resistance to Vip3Aa in field populations of H. armigera in Australia did not increase over the past...

  18. Characterization of the resistance to Vip3Aa in Helicoverpa armigera from Australia and the role of midgut processing and receptor binding.

    Science.gov (United States)

    Chakroun, Maissa; Banyuls, Núria; Walsh, Tom; Downes, Sharon; James, Bill; Ferré, Juan

    2016-01-01

    Crops expressing genes from Bacillus thuringiensis (Bt crops) are among the most successful technologies developed for the control of pests but the evolution of resistance to them remains a challenge. Insect resistant cotton and maize expressing the Bt Vip3Aa protein were recently commercialized, though not yet in Australia. We found that, although relatively high, the frequency of alleles for resistance to Vip3Aa in field populations of H. armigera in Australia did not increase over the past four seasons until 2014/15. Three new isofemale lines were determined to be allelic with previously isolated lines, suggesting that they belong to one common gene and this mechanism is relatively frequent. Vip3Aa-resistance does not confer cross-resistance to Cry1Ac or Cry2Ab. Vip3Aa was labeled with (125)I and used to show specific binding to H. armigera brush-border membrane vesicles (BBMV). Binding was of high affinity (Kd = 25 and 19 nM for susceptible and resistant insects, respectively) and the concentration of binding sites was high (Rt = 140 pmol/mg for both). Despite the narrow-spectrum resistance, binding of (125)I-labeled Vip3Aa to BBMV of resistant and susceptible insects was not significantly different. Proteolytic conversion of Vip3Aa protoxin into the activated toxin rendered the same products, though it was significantly slower in resistant insects. PMID:27095284

  19. Maize silk antibiotic polyphenol compounds and molecular genetic improvement of resistance to corn earworm (Helicoverpa zea Boddie in sh2 sweet corn

    Directory of Open Access Journals (Sweden)

    Baozhu Guo

    2010-01-01

    Full Text Available The flavor of sh2 super-sweet corn is preferred by consumers. Unfortunately, sh2 sweet corn has little genetic variation for insect resistance. In this paper we review the functions of two loci, p1 and a1. The P1 allele has a major role in sh2 sweet corn resistance to corn earworm, an allele that was lost in historical selection because of its pleiotropic effect on undesirable cob color and silk browning. The P1 allele has significant effects on biosyntheses of silk antibiotic compounds, maysin, apimaysin, methoxymaysin, and chlorogenic acid. The effect of a1 shows gene action for lowered maysin and significant epistatic action with p1. The dominant functional allele A1 causes anthocyanin pigments in aleurone, plant, and pericarp tissues; the recessive a1 allele causes absence of pigment in these tissues. If silk browning and cob color are critical factors for maysin production but lack the customer’s preference, then separating red cob and browning silk, which are controlled by the P1 allele, may be difficult if not impossible. One high silk maysin sh2 sweet corn germ­plasm, shrunken Zapalote Chico, has been released. There is some field corn germplasm with p1-wwr alleles, but the amount of antibiotic flavones and their potential as a donor need further investigation.

  20. Ha83, a Chitin Binding Domain Encoding Gene, Is Important to Helicoverpa armigera Nucleopolyhedrovirus Budded Virus Production and Occlusion Body Assembling.

    Science.gov (United States)

    Yu, Huan; Xu, Jian; Liu, Qiang; Liu, Tong-Xian; Wang, Dun

    2015-01-01

    Helicoerpa armigera nucleopolyhedrovirus (HearNPV) ha83 is a late expressed gene that encodes a chitin binding protein. Chitin domain truncation studies revealed that the cysteine at the 128 amino acid position probably played an important role in both chitin binding ability and protein transmission of Ha83. In order to study the function of ha83 in the HearNPV infection cycle, an ha83 knockout HearNPV (Ha83KO) was constructed via homologous recombination. Viral growth and viral DNA replication curves showed that fewer budded virions were produced in Ha83KO transfected cells, while viral DNA replication was increased. Electron microscopy revealed that fewer nucleocapsids were transmitted from virogenic stroma in the Ha83KO transfected cell nucleus, and the morphology of occlusion bodies was prominently larger and cube-shaped. Furthermore, DNA quantity in occlusion bodies of Ha83KO was significantly lower than the occlusion bodies of HaWT. The transcription analysis indicated that these changes may be due to the decreased expression level of viral structural associated genes, such as polyhedrin, p10, pif-2, or cg30 in Ha83KO infected cells. Above results demonstrated that the cysteine at the 128 amino acid position in Ha83 might be the key amino acid, and Ha83 plays an important role in BVs production and OBs assembling. PMID:26057202

  1. 影响微孢子虫对棉铃虫幼虫致病力的因子%Factors Affecting Pathogenicity of Microsporidian to Larvae of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    冉红凡; 潘文亮; 冯书亮; 范秀华; 王容燕

    2003-01-01

    1997年田间调查时,发现一种寄生于棉铃虫的微孢子虫,对棉铃虫具有很强的致病力.为明确环境因子对该微孢子虫及其致病力的影响,测定了温度与紫外线对该微孢子虫及其杀虫效果的影响.结果表明,该微孢子虫孢子耐受温度范围较宽,最高温度上限为55℃.温度对其致病力有显著影响,在一定温度范围内,随着生境温度的升高,微孢子虫对棉铃虫幼虫致病力增强.该微孢子虫对紫外线较敏感,在紫外线照射下易失活而丧失致病力.

  2. 棉铃虫齿唇姬蜂的生物学特性%BIONOMIC OF CAMPOLETIS CHLORIDEAE (HYM: ICHNEUMONIDAE)AS A PARASITOID OF THE COTTON BOLLWORM HELICOVERPA ARMIGERA ( LEP: NOCTUIDAE)

    Institute of Scientific and Technical Information of China (English)

    游兰韶; 雷润华; 蒋杰贤; 柏连阳; 肖治术

    2002-01-01

    研究了湖南长沙地区棉铃虫齿唇姬蜂的生物学特性及田间消长规律.棉铃虫齿唇姬蜂在湖南长沙地区年发生约10代,以7个世代发生在棉田.田间出现3个寄生高峰,分别在5月上旬-6月下旬、8月中旬-9月上甸及9月中旬-10月中旬,寄生率平均在25,l-63,1%.从卵发育到成虫的平均历期变化范围为32.C下13天至11.6.C下75.5天.棉铃虫齿唇姬蜂能寄主棉铃虫、斜纹夜蛾和甜菜夜蛾,但偏爱寄主棉铃虫.该蜂能寄生棉铃虫l-3龄幼虫,很少寄生4-6龄幼虫,喜寄生2-3龄幼虫,每雌可寄生斜纹夜蛾2龄幼虫5-23头.本文建立了发育速率及成蜂寿命与温度关系的回归模型,探讨了越冬问题.比较了长江流域和黄河流域棉铃虫齿唇姬蜂生物学特性的差异.%The bionomics of Campoletis chlorideae and the regularity of its seasonal fluctuations were studied inChangsha district, Hunan province. Field investigation indicated that there were ten generations of C. chlorideae ayear, of which seven occurred in cotton fields. Three peaks of cotton bollworm parasitization by C. chlorideae were ob-served, early May to late June, mid August to early September, mid September to mid October respectively. One peakoccurred in tomato and tobacco fields, the other two in cotton fields. The parasitization rate ranged from 25.1% -63.1%. The total development time from egg to adult ranged from 13.0 days at 32.C to 75.5 days at 11.6.C. Eachwasp could parasitize the 5 - 23 second instar larvae of tobacco caterpillar. C. chlorideae could parasitize the cottonbollworm, beet armyworm and tobacco caterpillar, but preferred the cotton bollworm larvae. C. chlorideae could para-sitized 1st - 3rd instar larvae of the tobacco caterpillar, but seldom parasitzed 4th - 6th instar larvae. Moreover, C.chlorideae preferred second instar larvae. Theoretical models for developmental speed, adult longevity and the influenceof temperature were proposed. The overwintering of C. chlorideae Uchida was also discussed. Moreover, methods forutilization of C. chlorideae Uchida in crop protection were presented and the bionomics of Campoletis chlorideae in boththe Yangtze River Valley and Yellow River Valley were compared.

  3. 几种药剂对新疆南疆地区棉花棉铃虫的防效%Control Effect of Different Pesticides Against Helicoverpa armigera In Cotton in Southern Xinjiang

    Institute of Scientific and Technical Information of China (English)

    王剑; 王锁牢; 李号宾; 李广阔; 姚举; 王伟

    2010-01-01

    [目的]自20世纪90年代中期以来棉铃虫在新疆南疆棉区严重发生,给新疆棉花生产造成了一定的损失.生产上滥用农药现象严重,造成防治效果不稳定,棉铃虫抗药性增强.为了有效控制棉铃虫为害,降低棉铃虫产生抗药性的速度.[方法]试验选择几种类型、作用方式不同的化学药剂,于2007、2008年在新疆莎车县进行了防治棉铃虫的田间药效试验.试验采用随机区组排列,在棉田二代棉铃虫卵高峰期至低龄幼虫期采用棉田自然虫口基数的基础上接虫进行田间试验.[结果]45%丙溴磷·高效氯氰菊酯EC 540~675 g a.i./hm2、40%丙溴磷EC 540~600 g a.i./hm2、5%氟铃脲EC 75 g a.i./hm2、40%毒死蜱EC 720 g a.i./hm2和1.8%阿维菌素EC 18.9 g a.i./hm2等药剂在试验浓度下对棉花安全,优于35%硫丹EC和2.5%高效氯氟氰菊酯EW 2对照药剂的防效或与其效果相当.[结论]防治棉铃虫,可采用以上几种化学农药及用量在当地替代常用药剂或与其交替使用进行防治.

  4. Response of last instar Helicoverpa armigera larvae to Bt toxin ingestion: changes in the development and in the CYP6AE14, CYP6B2 and CYP9A12 gene expression.

    Directory of Open Access Journals (Sweden)

    Pilar Muñoz

    Full Text Available Bt crops are able to produce Cry proteins, which were originally present in Bacillus thuringiensis bacteria. Although Bt maize is very efficient against corn borers, Spanish crops are also attacked by the earworm H. armigera, which is less susceptible to Bt maize. Many mechanisms could be involved in this low susceptibility to the toxin, including the insect's metabolic resistance to toxins due to cytochrome P450 monooxygenases. This paper examines the response of last instar H. armigera larvae to feeding on a diet with Bt and non-Bt maize leaves in larval development and in the gene expression of three P450 cytochromes: CYP6AE14, CYP6B2 and CYP9A12. Larvae fed on sublethal amounts of the Bt toxin showed reduced food ingestion and reduced growth and weight, preventing most of them from achieving the critical weight and pupating; additionally, after feeding for one day on the Bt diet the larvae showed a slight increase in juvenile hormone II in the hemolymp. Larvae fed on the non-Bt diet showed the highest CYP6AE14, CYP6B2 and CYP9A12 expression one day after feeding on the non-Bt diet, and just two days later the expression decreased abruptly, a finding probably related to the developmental programme of the last instar. Moreover, although the response of P450 genes to plant allelochemicals and xenobiotics has been related in general to overexpression in the resistant insect, or induction of the genes when feeding takes place, the expression of the three genes studied was suppressed in the larvae feeding on the Bt toxin. The unexpected inhibitory effect of the Cry1Ab toxin in the P450 genes of H. armigera larvae should be thoroughly studied to determine whether this response is somehow related to the low susceptibility of the species to the Bt toxin.

  5. Preliminary Study on Insecticidal Activity of Transgenic Corn Expressing Bt Insecticidal Protein Gene to Helicoverpa armigera Hübner%转Bt基因抗虫玉米对棉铃虫杀虫活性的初步评价

    Institute of Scientific and Technical Information of China (English)

    芮昌辉; 范贤林; 孟香清; 董丰收

    2000-01-01

    @@ 国内外在转Bt基因抗虫作物的研究和应用上已取得重大进展,其中Bt抗虫棉已在美国、澳大利亚、中国等进入商品化应用阶段,近年来种植面积增长很快,并取得了显著的经济、生态 和社会效益.

  6. Can a fake fir tell the truth about Swiss needle cast?

    Science.gov (United States)

    A key question in dendrochronology to reconstruct forest disturbance history is how to distinguish between the effects of Swiss needle cast (SNC) and other forest disturbance agents (e.g., Douglas-fir beetle, tussock moth, western spruce budworm, laminated root rot, Armillaria ro...

  7. Differential activity of multiple saponins against omnivorous insects with varying feeding preferences

    Science.gov (United States)

    A variety of saponin glycosides and aglycones from seven different plant families (Aquifoliaceae, Asparagaceae, Caryophyllaceae, Dioscoreaceae, Leguminosae, Rosaceae, Sapindaceae) were tested against the corn earworm, Helicoverpa zea, and the fall armyworm, Spodoptera frugiperda. The corn earworm fe...

  8. Fight plant pests using RNA interference

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ CAS plant physiologists have recently invented a plant-mediated RNA interference (RNAi) technique to effectively and specifically control the gene expression of the cotton bollworm (Helicoverpa armigera) and stunt its growth.

  9. Lack of detrimental effects of Bacillus thuringiensis Cry toxins on the insect predator Chrysoperla carnea: a toxicological, histopathological, and biochemical analysis

    NARCIS (Netherlands)

    Rodrigo-Simón, A.; Maagd, de R.A.; Avilla, C.; Bakker, P.L.; Molthoff, J.W.; González-Zamora, J.; Ferré, J.

    2006-01-01

    The effect of Cry proteins of Bacillus thuringiensis on the green lacewing (Chrysoperla carnea) was studied by using a holistic approach which consisted of independent, complementary experimental strategies. Tritrophic experiments were performed, in which lacewing larvae were fed Helicoverpa armiger

  10. Holocene occurrence of Lophodermium piceae, a black spruce needle endophyte and possible paleoindicator of boreal forest health

    Science.gov (United States)

    Jasinski, J. P. Paul; Payette, Serge

    2007-01-01

    Holocene occurrences of conifer needle endophytes have not previously been reported. We report the fossil remains of Lophodermium piceae (Fckl.) Hoehn., a fungal endophyte of black spruce ( Picea mariana (Mill.) B.S.P.) needles, in macrofossils dating back to 8000 cal yr BP. Spruce budworm head capsules and L. piceae remains were found preceding charcoal layers delineating the transformation of four spruce-moss forest sites to spruce-lichen woodland. As L. piceae is found solely on senescent needles, its increased presence during these transformation periods likely indicates that the forests were in decline due to the spruce budworm ( Choristoneura fumiferana (Clem.)) when they burned. Future paleoecological studies incorporating needle fungi observations could be used to investigate the historical occurrence of tree disease and the role of fungi in forest health and decline.

  11. A Three-Year Field Validation Study to Improve the Integrated Pest Management of Hot Pepper

    OpenAIRE

    Kim, Ji-Hoon; Yun, Sung-Chul

    2013-01-01

    To improve the integrated pest management (IPM) of hot pepper, field study was conducted in Hwasung from 2010 to 2012 and an IPM system was developed to help growers decide when to apply pesticides to control anthracnose, tobacco budworm, Phytophthora blight, bacterial wilt, and bacterial leaf spot. The three field treatments consisted of IPM sprays following the forecast model advisory, a periodic spray at 7-to-10-day intervals, and no spray (control). The number of annual pesticide applicat...

  12. Combined action of sex pheromone and wasp apanteles gelechiidivoris in greenhouse tomato crops

    OpenAIRE

    Jessica Andrea Morales; Laura Yasmith Muñoz; Daniel Rodríguez Caicedo; Fernando Cantor

    2014-01-01

    The tomato budworm, Tuta absoluta, is considered main pest of tomato crops. Control of this pest is performed with hemicals, although, there are other strategies such as biological and ethological control. In Colombia there is not precedent that combines both strategies: ethological control with sexual pheromone and biological control with Apanteles gelechiidivoris, for the control of this pest in tomato crops. In this work four different treatments under greenhouse conditions were evaluated ...

  13. Generation of a Transcriptome in a Model Lepidopteran Pest, Heliothis virescens, Using Multiple Sequencing Strategies for Profiling Midgut Gene Expression

    OpenAIRE

    Perera, Omaththage P.; Shelby, Kent S.; Holly J.R. Popham; Fred Gould; Adang, Michael J; Juan Luis Jurat-Fuentes

    2015-01-01

    Heliothine pests such as the tobacco budworm, Heliothis virescens (F.), pose a significant threat to production of a variety of crops and ornamental plants and are models for developmental and physiological studies. The efforts to develop new control measures for H. virescens, as well as its use as a relevant biological model, are hampered by a lack of molecular resources. The present work demonstrates the utility of next-generation sequencing technologies for rapid molecular resource generat...

  14. Defoliation of interior Douglas-fir elicits carbon transfer and stress signalling to ponderosa pine neighbors through ectomycorrhizal networks

    OpenAIRE

    Song, Yuan Yuan; Simard, Suzanne W.; Carroll, Allan; Mohn, William W.; Zeng, Ren Sen

    2015-01-01

    Extensive regions of interior Douglas-fir (Pseudotsuga menziesii var. glauca, IDF) forests in North America are being damaged by drought and western spruce budworm (Choristoneura occidentalis). This damage is resulting from warmer and drier summers associated with climate change. To test whether defoliated IDF can directly transfer resources to ponderosa pine (Pinus ponderosae) regenerating nearby, thus aiding in forest recovery, we examined photosynthetic carbon transfer and defense enzyme r...

  15. Highlights of forest pest conditions in the maritimes at the end of June, 1993. Technical note No. 285. Annual publication

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.E.

    1993-01-01

    This note describes forest pest conditions in the Maritimes at the end of June, 1993. It discusses diseases and pests found including forest tent caterpiller, gypsy moth, red shoots of balsam fir, aspen leafroller, spruce budworm, poplar serpentine leafminer, maple leafroller, and spruce spider mite. Others include elm leafminer, leafroller of birch, satin moth, cherry blight, aspen twoleaf, fall cankerworm, winter moth, and leaf and twig blight of aspen.

  16. Results of three years of experimental aerial application of Bacillus thuringiensis at 2. 0 l/ha against choristoneura fumiferana c. Information report No. LAU-X-89B

    Energy Technology Data Exchange (ETDEWEB)

    Valero, J.R.

    1989-01-01

    Research into the potential of using Bacillus thuringiensis 3a3b for control of the spruce budworm led to the development of a concentrated, effective and economical suspension of B.t. called Futura. This report gives the results of spraying Futura in the Saguenay/Lac St.-Jean and Lower St. Lawrence regions of Quebec in 1985, 1986 and 1987. Eight blocks of mature forest dominated by fir and white spruce were treated using two different strengths.

  17. 棉铃虫核型多角体病毒感染对宿主昆虫GST活性及其表达水平的影响%Effect of Helicoverpa armigera nucleopolyhedrovirus infection on GST activity and GST expression on host insect

    Institute of Scientific and Technical Information of China (English)

    黄诗迪; 黄彩萍; 于欢; 王敦

    2015-01-01

    [目的]研究棉铃虫核型多角体病毒(HearNPV)感染宿主昆虫后对宿主谷胱甘肽S转移酶(GST)活性与基因表达水平的影响,明确病毒在侵染宿主过程中对宿主昆虫GST的调控作用.[方法]采用50和100 PIB/只2种剂量的HearNPV病毒感染3龄棉铃虫,测定感染后不同时间试虫中肠GST活性与其编码基因的表达水平,对比分析病毒感染与未感染健康试虫的GST活性及其编码基因表达水平的差异.[结果]棉铃虫在HearNPV感染初期,GST活性显著提高,同时GST表达水平显著上调;随着感染时间的推移,GST活性与其编码基因的表达水平均显著下降,表明病毒感染后对宿主昆虫GST活性的影响与其对GST表达水平的调控相关.[结论]HearNPV感染棉铃虫过程中,病毒入侵能够激活宿主GST基因的表达,但病毒的持续感染最终会抑制GST编码基因的表达水平.

  18. C3和C4植物寄主对华北地区棉铃虫越冬代和第一代的影响%Contribution of C3 and C4 host plants for the overwintering and 1st generation of Helicoverpa armigera(Hübner)in Northern China

    Institute of Scientific and Technical Information of China (English)

    叶乐夫; 付雪; 戈峰

    2011-01-01

    It is a key step for cotton bollworm (CBW) management to determine the ratio of moths of cotton bollworm originating from C3 and C4 host plants for the overwintering generation and their contribution to the next spring first generation in North China. In this study, the development times of larva from the female moths captured in wheat field in 2007 were observed systematically. Moreover, δ13C values in the wings of each female moth were tested with GC-MS apparatus to determine larval host plant type. Results showed that 53.1% of moths trapped during spring emergence (the overwintering generation CBW) came from larva grown in late autumn C3 host plants (cotton), 46.9% came from larva grown in late autumn C4 host plants (corn). 57.9% of eggs laid by the overwintering generation moths were determined as progeny of C3 phenotype via stable isotope examination on the wings of moth, individually. Significantly higher hatching rate were observed in the eggs laid by the moths from larva grown in C3 host plants than C4 host plants. Furthermore, about 63.7% first instar larva on spring wheat was determined as progeny of C3 phenotype moths. Moreover, about 47.9% larva at the third instar, 45.5% fourth instar larva, 46.9% fifth instar larva, 55.1% last instar larva of 1st generation of CBW originated from C3 host plants. The larva from first instar to third instar of moths from C3 phenotype develop quicker compared with from C4 phenotype. However, larva from fourth instar to sixth instar from C3 phenotype developed slowly than C4 phenotype. The larva originated from C3 phenotype displayed lower survival rate at lower instar larva and higher survival rate at higher instar larva while compared to the C4 phenotype progeny. In the whole, quicker development for lower instar larva with lower survival rate, and slower development for large larva with higher survival rate occurred during their larval developmental process, However, total developmental duration and accumulative survival rate of larva as progeny of different phenotype CBW from C3 .and C4 host plants were not significant. No significant difference of fitness of first generation of CBW from C3 or C4 was observed, indicating that the larva of CBW has adapted to this host plant variation. Generally speaking, the overwintering generation CBW, which originated from C3 or C4 host plants, as pupae, could overwinter successfully in North China, and provided equal quantity of moths in the next spring, therefore infested on the spring wheat, contributing comparative number of larva to the first generation CBW. On the other hand, spring wheat, as major host plant of first generation CBW in North China, could determine the larval developmental process through its nutrition component shift although their moth could come from C3 host plants or C4 host plants. Our research provided an effective and direct estimation of contribution by corn and cotton host plants to the overwintering generation and spring first generation CBW population in North China, and would be a key reference in making Bt management strategies to prevent local breakout of CBW.%确定华北越冬代棉铃虫虫源及其对第一代棉铃虫种群的影响是制定棉铃虫防治策略的基础.以越冬代棉铃虫蛾翅的稳定同位素813C为天然标记直接判定这些成虫的幼虫期寄主类型,并将雌虫接到春小麦植株上,调查其产卵、孵化、幼虫发育至化蛹、羽化等特征.结果表明,越冬代来自C3植物(主要为棉花)的成虫个体数量占全部越冬羽化种群的53.1%,所产生的下一代老熟幼虫也较C4来源的多(55.1%);雌蛾受精率都比较高;卵孵化率较高(52.9%>41.6%);幼虫发育在低龄阶段较比后者快,存活率低,但在高龄幼虫阶段相对后者慢,存活率高;与C4植物(主要玉米)的来源个体后代的幼虫发育总历期接近,总存活率也相近.显示寄主植物小麦提供的营养条件在第一代棉铃虫的幼虫发育中具有决定性意义,即小麦只在特定阶段才适合幼虫的发育;而且不论是C3还是C4寄主来源的越冬代棉铃虫已经适应了这一限制.有效地评价了玉米和棉花等寄主植物对华北地区越冬代和次年第一代棉铃虫的影响,对于分析越冬代棉铃虫的虫源性质和第一代棉铃虫的防治及Bt抗性的治理有重要参考价值.

  19. 玉米田四代棉铃虫老熟幼虫空间分布型应用%Spatial Distribution Pattern Application of Fourth-Generation Mature Larvae of Cotton Bollworm (Helicoverpa armigera Hübner) in Maize Field

    Institute of Scientific and Technical Information of China (English)

    李贺年; 齐巧丽; 李德新; 姚克荣

    2011-01-01

    [ Objective ] The paper was to study the spatial distribution pattern of fourth-generation mature larvae of cotton bollworm in maize field. [ Method] The plots with different occurrence densities of fourth-generation cotton bollworm were investigated during August to September in 2009. Six groups of sampling data were obtained, and seven indicators were used to determined its spatial distribution pattern. including aggregation index method, lwao method and Taylor method, etc. [ Result] Aggregation index test showed that in all plots, Moore I < 0,Lloyod m*/m < 1, Kuno Ca <0, diffusion coefficient C < 1, diffusion index Iδ < 1, negative binomial distribution K <0, indicating that mature larvae of cotton bollworm showed uniform distribution in summer maize. Iwao regression equation of fourth-generation mature larvae of cotton bollworm in summer maize was m * =0. 090 6 +0. 766 9m, r =0.986 3, indicating that the basic components of cotton bollworm distribution was single individual, and mature larvae of cotton bollworm in summer maize showed uniform distribution. The optimal sampling number of fourth-generation mature larvae of cotton bollwonn in maize under different population densities could be calculated using formula N1 =( 1. 090 6/m - 0. 233 1 )/D2. [ Conclusion ] The result provided basis for accurate evaluation of population quantities and variation law of cotton bollworm, as well as prediction and control of the pest.%[目的]研究玉米田四代棉铃虫老熟幼虫空间分布型.[方法]于2009年8~9月,对第4代棉铃虫不同发生密度地块进行调查,取得了6组样本资料,应用聚集度指标法、Iwao法和Taylor法等7种指标分析,对其空间分布型进行检验.[结果]聚集度指标的检验结果表明:所有样地Moore I<0,Lloyod m*/m<1,Kuno Ca<0,扩散系数C<1,扩散型指数 Iδ<1,负二项分布,K<0,表明棉铃虫老熟幼虫在夏玉米上均呈均匀分布.棉铃虫第4代老熟幼虫在夏玉米上的Iwao回归方程为m*=0.090 6+0.766 9m,r=0.986 3;说明棉铃虫分布的基本成分为单个个体,老熟幼虫在夏玉米上呈均匀分布.利用公式N1 =(1.090 6/m-0.233 1)/D2即可求出棉铃虫第4代老熟幼虫在玉米上不同密度下的最适抽样数.[结论]研究结果为准确佑值棉铃虫种群数量及变动规律,为预测及防治棉铃虫提供依据.

  20. Noctuid migration in the nocturnal aeroecological boundary layer

    Science.gov (United States)

    Long-distance migration of adult corn earworm moths (Helicoverpa zea), and several other noctuid moth species, facilitates seasonal expansion of pest populations and consequent increased infestations of agricultural crops on a continental scale in North America. Long-term field studies of populatio...

  1. Biocontrol potential of Steinernema thermophilum and its symbiont Xenorhabdus indica against lepidopteran pests: virulence to egg and larval stages

    Science.gov (United States)

    Under laboratory conditions, the biocontrol potential of Steinernema thermophilum was tested against eggs and larval stages of two important lepidopteran insect pests, Helicoverpa armigera and Spodoptera litura (polyphagous pests), as well as Galleria mellonella (used as a model host) . In terms of ...

  2. A selective CAP2b neuropeptide antagonist for an expressed receptor from the red flour beetle, Tribolium castaneum

    Science.gov (United States)

    Diapause hormone (DH) is an insect neuropeptide that is highly effective in terminating the overwintering pupal diapause in members of the Helicoverpa/Heliothis complex of agricultural pests, thus DH and related compounds have promise as tools for pest management. To augment our development of effec...

  3. A New Strategy of Insect Pest Control:Down-regulating Cotton Boliworm Gene Expression by Engineering Plant Double Stranded RNA

    Institute of Scientific and Technical Information of China (English)

    MAO Ying-bo; XUE Xue-yi; WANG Ling-jiang; CHEN Xiao-ya

    2008-01-01

    @@ Cotton bollworm (Helicoverpa armigera ) is an important agricultural pest that causes severeyield loss to crops,particularly to cotton.Transgenic Bt crops have been successful in protectingplants,however,Bt proteins are toxic to all lepidopteran insects but have little effects to sucking pests,such as aphids.Furthermore,the continuous use of Bt crops increases insect resistance.

  4. Structural basis of the resistance of an insect carboxypeptidase to plant protease inhibitors

    NARCIS (Netherlands)

    Bayés, A.; Comellas-Bigler, M.; Rodriquez de la Vega, M.; Maskos, K.; Bode, W.; Aviles, F.X.; Beekwilder, M.J.; Vendrell, J.

    2005-01-01

    Corn earworm (Helicoverpa zea), also called tomato fruitworm, is a common pest of many Solanaceous plants. This insect is known to adapt to the ingestion of plant serine protease inhibitors by using digestive proteases that are insensitive to inhibition. We have now identified a B-type carboxypeptid

  5. Competitive release and outbreaks of non-target pests associated with transgenic Bt cotton

    Science.gov (United States)

    This study tests a competitive release hypothesis that Helicoverpa zea larval herbivory will 1) deter oviposition and increase leaving rates of the stink bugs, Euchistus servus and Nezara viridula and that 2) that these effects will be stronger for E. servus than for N. viridula. By spatially separa...

  6. Development of Transgenics in Chickpea.

    Science.gov (United States)

    Chickpea (Cicer arietinum L.) is an important food crop in much of the developing world and ranks third in production among food legumes. Chickpea production is limited worldwide by drought, insect damage from Helicoverpa armigera, Callosobruchus maculatus and C. chinensis and disease pressure from ...

  7. Noise in an insect outbreak model

    CERN Document Server

    Bao Quan; Wang Xian Ju; Liu Guo Tao; We De Hua; Xie Hui Zhang; Liu Liang Gang

    2003-01-01

    We study the steady state properties of an insect (spruce budworm) outbreak model in the presence of Gaussian white noise. Based on the corresponding Fokker-Planck equation the steady state solution of the probability distribution function and its extrema have been investigated. It was found that fluctuations of the insect birth rate reduces the population of the insects while fluctuations of predation rate and the noise correlation can prevent the population of the insects from going into extinction. Noise in the model can induce a phase transition.

  8. Defoliation of interior Douglas-fir elicits carbon transfer and stress signalling to ponderosa pine neighbors through ectomycorrhizal networks.

    Science.gov (United States)

    Song, Yuan Yuan; Simard, Suzanne W; Carroll, Allan; Mohn, William W; Zeng, Ren Sen

    2015-01-01

    Extensive regions of interior Douglas-fir (Pseudotsuga menziesii var. glauca, IDF) forests in North America are being damaged by drought and western spruce budworm (Choristoneura occidentalis). This damage is resulting from warmer and drier summers associated with climate change. To test whether defoliated IDF can directly transfer resources to ponderosa pine (Pinus ponderosae) regenerating nearby, thus aiding in forest recovery, we examined photosynthetic carbon transfer and defense enzyme response. We grew pairs of ectomycorrhizal IDF 'donor' and ponderosa pine 'receiver' seedlings in pots and isolated transfer pathways by comparing 35 μm, 0.5 μm and no mesh treatments; we then stressed IDF donors either through manual defoliation or infestation by the budworm. We found that manual defoliation of IDF donors led to transfer of photosynthetic carbon to neighboring receivers through mycorrhizal networks, but not through soil or root pathways. Both manual and insect defoliation of donors led to increased activity of peroxidase, polyphenol oxidase and superoxide dismutase in the ponderosa pine receivers, via a mechanism primarily dependent on the mycorrhizal network. These findings indicate that IDF can transfer resources and stress signals to interspecific neighbors, suggesting ectomycorrhizal networks can serve as agents of interspecific communication facilitating recovery and succession of forests after disturbance. PMID:25683155

  9. Do Offspring of Insects Feeding on Defoliation-Resistant Trees Have Better Biological Performance When Exposed to Nutritionally-Imbalanced Food?

    Science.gov (United States)

    Quezada-Garcia, Roberto; Fuentealba, Alvaro; Nguyen, Ngoc; Bauce, Éric

    2015-01-01

    White spruce (Picea glauca (Moench) Voss) trees that are resistant or susceptible to spruce budworm (Choristoneura fumiferana (Clem.)) attack were identified in a southern Quebec plantation. Due to high mortality-induced selective pressures imposed by resistant trees on spruce budworm larvae, insects that survive on resistant trees exhibited greater biological performance than those on susceptible trees. We tested the hypothesis that this better biological performance is maintained across generations when progeny were subjected to nutritional stress. We collected pupae from resistant and susceptible trees (phenotype). Adults were reared under controlled laboratory conditions. Progeny were subsequently reared on two types of artificial diet (high vs. low quality). Low quality diet simulated food quality deterioration during outbreak conditions. Results confirmed that surviving insects collected from resistant trees have better performance than those from susceptible trees. Offspring performance (pupal mass, developmental time) was affected only by diet quality. These results suggest that adaptive advantages that would be acquired from parents fed on resistant trees are lost when progeny are exposed to nutritionally-imbalanced food, but the effects persist when larvae are fed a balanced diet. Offspring mortality, fecundity and fertility were positively influenced by parental origin (tree phenotype).

  10. Degeneration of host prothoracic glands caused by Campoletis chlorideae polydnavirus

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cong; YAN Yunhua; WANG Chenzhu

    2003-01-01

    The development of last instar Helicoverpa armigera prothoracic glands was investigated first; then the effects on the prothoracic glands of Helicoverpa armigera was studied by injection with calyx fluid and polydnavirus (PDV) from the endoparasitoid Campoletis chlorideae. Results showed that 3 female equivalents of calyx fluid or 4 female equivalents of PDV induced degeneration of host prothoracic glands. 24 h after calyx fluid or PDV injection the ultrastructure of the gland cells showed a significant decrease in intercellular channel system, while an increase in the number of round mitochondria, lysosomes and whorled figures, the organelle of some cells has degenerated and only organelle debris remained in the cells. These results suggest that calyx fluid or PDV cause the inactivation and degeneration of host prothoracic glands.

  11. History and Current Status of Development and Use of Viral Insecticides in China

    Directory of Open Access Journals (Sweden)

    Xiulian Sun

    2015-01-01

    Full Text Available The use of insect viruses as biological control agents started in the early 1960s in China. To date, more than 32 viruses have been used to control insect pests in agriculture, forestry, pastures, and domestic gardens in China. In 2014, 57 products from 11 viruses were authorized as commercial viral insecticides by the Ministry of Agriculture of China. Approximately 1600 tons of viral insecticidal formulations have been produced annually in recent years, accounting for about 0.2% of the total insecticide output of China. The development and use of Helicoverpa armigera nucleopolyhedrovirus, Mamestra brassicae nucleopolyhedrovirus, Spodoptera litura nucleopolyhedrovirus, and Periplaneta fuliginosa densovirus are discussed as case studies. Additionally, some baculoviruses have been genetically modified to improve their killing rate, infectivity, and ultraviolet resistance. In this context, the biosafety assessment of a genetically modified Helicoverpa armigera nucleopolyhedrovirus is discussed.

  12. Developing a neem-based pest management product: laboratory evaluations of neem extracts on insect pests resistance to synthetic pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Permana, A.D.; Rahadian, R.; Wibowo, S.A

    1998-12-16

    Laboratory studies has been conducted as a part of a project aimed at the development of a neem-based insecticide for pest management purposes. Permethrin, a pyrethroid insecticide, and neem (Azadirachta indica) products were tested against larvae of Diamondback Moth Plutella xylostella, and Helicoverpa armigera collected from several locations in West Java, Indonesia. The results of bioassay showed that the average LC{sub 50} values of permethrin for Plutella xylostella had been 60-100 fold higher as compared with the normal dosage recommended. Similarly, the LC{sub 50} values obtained for Helicoverpa armigera had been 46-73 fold as compared with the recommended dosage. These facts suggest that both insects have developed resistance to permethrin. The results of bioassay with neem-products tested against Plutella xylostella and Helicoverpa armigera larvae showed that statistically LC{sub 50} values of neem-products for each strain of either Plutella xylostella or Helicoverpa armigera were not significantly different one to another. We also found that neem-treated insects, even though they were not killed directly by the insecticide, were not able to molt to the next instar or pupae, so that very low percentage of adults emerged. The susceptibility of neem-products could not be easily determined by only measuring the LC{sub 50} values from the larval stage, but the disruption of the growth and development of the insect should be considered as well. Our findings suggest that neem-products could be used effectively to control insects which have developed resistance to conventional insecticide. (author)

  13. Genetic mechanisms underlying apimaysin and maysin synthesis and corn earworm antibiosis in maize (Zea mays L.).

    OpenAIRE

    Lee, E A; Byrne, P.F.; McMullen, M D; Snook, M E; Wiseman, B. R.; Widstrom, N W; Coe, E. H.

    1998-01-01

    C-glycosyl flavones in maize silks confer resistance (i.e., antibiosis) to corn earworm (Helicoverpa zea [Boddie]) larvae and are distinguished by their B-ring substitutions, with maysin and apimaysin being the di- and monohydroxy B-ring forms, respectively. Herein, we examine the genetic mechanisms underlying the synthesis of maysin and apimaysin and the corresponding effects on corn earworm larval growth. Using an F2 population, we found a quantitative trait locus (QTL), rem1, which account...

  14. A Survey of the Insect Pests and Farmers' Practices in the Cropping of Tomato in Nigeria

    OpenAIRE

    Umeh, VC.; Kuku, FO.; Nwanguma, EI.; Adebayo, OS.; Manga, AA.

    2002-01-01

    A survey of some tomato producing areas of Nigeria indicated that the major insects attacking tomato included the fruit borer Helicoverpa armigera Hübner, the grasshopper Zonocerus variegatus L., the whitefly Bemisia tabacci Gennadius, and various species of aphids, mostly Aphis gossypii Glover. Interviews conducted to assess farmers' practices which contribute to insect damage showed that inappropriate application of insecticides and the use of wrong dosages may have contributed to insect co...

  15. Recent Advances in Biological Control of Pest Insects by Using Viruses in China

    Institute of Scientific and Technical Information of China (English)

    Xiu-lian SUN; Hui-yin PENG

    2007-01-01

    Insect viruses are attractive as biological control agents and could be a feasible alternative to chemical insecticides in the management of insect infestations. This review describes recent advances in the development of wild-type and genetically modified viruses as insecticides. A new strategy of application of insect viruses in China is reviewed. Also, the assessment of biosafety of genetically modified Helicoverpa armigera Nucleopolyhedovirus (HearNPV) is emphasized as a case-study.

  16. G-protein-coupled receptor controls steroid hormone signaling in cell membrane

    OpenAIRE

    Wang, Di; Zhao, Wen-Li; Cai, Mei-Juan; Wang, Jin-Xing; Zhao, Xiao-Fan

    2015-01-01

    G-protein-coupled receptors (GPCRs) are involved in animal steroid hormone signaling, but their mechanism is unclear. In this research, we report that a GPCR called ErGPCR-2 controls steroid hormone 20-hydroxyecdysone (20E) signaling in the cell membrane of the lepidopteran insect Helicoverpa armigera. ErGPCR-2 was highly expressed during molting and metamorphosis. 20E, via ErGPCR-2, regulated rapid intracellular calcium increase, protein phosphorylation, gene transcription, and insect metamo...

  17. Streptomyces avermitilis from marine

    Institute of Scientific and Technical Information of China (English)

    XIONG Li-xia; LI Jian-zhong; WANG Hui-li

    2005-01-01

    The insecticidal strain 173 was isolated from marine source and its activity was explored by the bioassay of brine shrimp and Helicoverpa armigera. Based on morphological, physiological and molecular properties, the insecticidal strain 173 was identified as Streptonycetes avermitilis, which is the best insecticidal microorganism found in the terrestrial environment. The taxonomy of the strain173, insecticidal spectrum and properties of the corresponding insecticidal antibiotics are reported.

  18. 两种夜蛾科昆虫卵的超微形态特征对比研究%Comparative Study on Morphological Characteristics of Ova from Two Species in Noctuidae

    Institute of Scientific and Technical Information of China (English)

    孙会忠; 董钧锋; 宋月芹; 张友军

    2011-01-01

    [Objective] The aim was to explore the morphological characteristics of ovum from Spodoptera exigua and Heliothis assulta. [Method]The ultra morphological characteristics of ovum was observed with scanning electron microscope (SEM). [Result] The ova from S. exigua and H. assulta are all spheroid, the former has net line decoration on surface, with some aeropyle distributed on the net line decoration; the micropyle is located in the center of polar and has plum flower-like engraving; the surface of chorien of the latter has the parallel crowns through two polar. Between the parallel crown, the surface of chorion has the decorated trapezium line, all crowns of second polar zone have breast-tuber that distributes in parallel at the same latitude in line, and there is no aeropyle distributing on chorion. [Conclusion] The ultra morphological characteristics of the ova from two Noctuidae species showed significant difference to each other, which enriched ontogenesis data and also provided reference for the accurate identification of two kinds of ova.%[目的]探索甜菜夜蛾和烟青虫卵的形态学特征,为卵的发育及种群鉴定积累资料.[方法]运用扫描电子显微镜对两种昆虫卵的超微结构特征进行观察.[结果]甜菜夜蛾和烟青虫的卵均为球状,前者卵壳表面具网状纹饰,且分布有较多的呼吸空,卵孔外围的梅花状刻纹卵石状;后者卵壳表面隆起贯穿两极,隆起间具梯形纹饰,亚极区的隆起上分布有乳突,未见呼吸孔的分布.[结论]甜菜夜蛾和烟青虫卵的超微结构特征存在种间特异性,超微特征丰富了两种昆虫的个体发育资料,也为两种昆虫的卵及其外类群的准确鉴定提供参考.

  19. 白僵菌对烟蚜的致病性研究%Study on Pathogenicity of Beauveria bassiana on Tobacco Aphid

    Institute of Scientific and Technical Information of China (English)

    黄刚; 徐明勇; 钱凤英; 张西仲

    2011-01-01

    [Objective] The aim was to explore the pathogenicity of Beauveria bassiana on tobacco aphid. [ Method] The pathogenicity of four Beauveria bassiana (B-l ,B-2,B-3 and B-4)strains on the tobacco budworm was studied. [ Result] Different tested Beauveria bassiana strains had different levels of insecticidal effect on tobacco aphids. The corrected mortality of tobacco budworm treated by B-3 was more than 95% ; the mortality rates of conidia of B-l and B-2 strains against tobacco aphid were over 80% , and their hyphae also caused higher morbidity a-gainst tobacco aphid; metabolites of different strains of had a strong contact action against tobacco budworm, and all the mortality rates of metabolites of different strains against tobacco aphid were over 85% after 48 h treatment. [Conclusion] The research provides reference for further study on microbial control of tobacco aphid.%[目的]探讨白僵菌(Beauveria bassiana)对烟蚜的致病性.[方法]以4株球孢白僵菌(B-1、B-2、B-3和B-4)为供试菌株,测定其对烟草蚜虫的致病性.[结果]受测的4株白僵菌菌株对烟草蚜虫均有不同程度的杀虫效果.其中,B-3处理烟草蚜虫的校正死亡率达到95%以上,B-1、B-2菌株的分生孢子处理烟草蚜虫的校正死亡率超过80%,其菌丝对蚜虫也有较高的致病率;4株菌株的代谢产物对烟草蚜虫均有较强的触杀作用,施用48 h后其烟草蚜虫的校正死亡率均超过85%.[结论]为烟草蚜虫的微生物防治研究提供了参考.

  20. Scenario of Entomological Research in Legume Crops in Nepal

    Directory of Open Access Journals (Sweden)

    Bishnu Prasad Neupane

    2015-09-01

    Full Text Available This review paper highlights scenario of entomological research in grain legumes in Nepal into headings of the monitoring, survey and surveillance, insect pest management, existing problem and future strategies. A survey study on yield loss assessment of chickpea due to Helicoverpa pod borer under field condition has been recorded up to 75% in the year 1996-1998 at Banke and Bardiya district. While monitored Helicoverpa armigera through pheromone trap, during the 2nd week of March, peak catches of 91 male moths were recorded at Rampur, while it was the maximum (42 male moths during the 3rd week of March. Synthetic pyrethroids, deltamethrin, fenvalerate and cypermethrin used at 0.01% concentration (a.i., were effective in controlling the chickpea pod borer, Helicoverpa armigera Hubner. Genotypes NCH-18, NCH -31, NCH-138 and ICC 3075 WR were found resistant. Ripcord 10%@0.05% was found to be superior and effective chemical insecticides to control stem fly and soybean hairy caterpillar. The late sowing date December, 10 showed significantly higher percentage of chickpea pod borer damage with lower grain yield. Inter crops combinations of Chickpea +wheat (2:1 ratio was found effective against Helicoverpa armigera damage (1.2% followed by chickpea+barley (2.36% and Chickpea+linseed (2:1 ratio (3.7%. Bakaino (Melia azederach L. was identified as the best indigenous pesticides to check the normal growth of hairy caterpillar (Spilarctia casigneta kollar under laboratory condition. Metarhizium anisopliae was found effective for the management of Helicoverpa armigera that caused maximum mortality (94.67%, infection (45.33% within 7.49 days (LT50. Similarly, Beauveria bassiana caused maximum mortality (98.67%, infection (80.00% with the least LT50 value (5 days. Crop sprayed with HaNPV had the lowest pod damage (0.3% and the highest in Racer (2.2%. This review work provided a lot of information to conduct entomological research activity conducted in grain

  1. Climatic change and indigenous and non-indigenous ravagers : a new reality?; Changements climatiques et les ravageurs indigenes et exotiques : une nouvelle realite?

    Energy Technology Data Exchange (ETDEWEB)

    Regniere, J.; Cooke, B.; Logan, J.A.; Carroll, A.; Safranyik, L. [Natural Resources Canada, Ottawa, ON (Canada). Canadian Forest Service

    2005-07-01

    The impact that climate change may have on ecological diversity was discussed with particular reference to the movement of indigenous and non-indigenous insects that are harmful to trees. Insects in particular, are more likely to evolve rapidly and adapt to ecological change. Those with a high rate of reproduction and which can move long distances will colonize new habitats and survive a wide range of bio-physical conditions. This PowerPoint presentation included a series of graphs, tables and charts to illustrate the increased presence of various harmful insects in northern forests, including the balsam twig aphid, balsam gall midge, gypsy moth, hemlock looper, western spruce budworm, and forest tent caterpillar. It was shown that large changes in ecosystems are expected to occur at northern latitudes and higher altitudes. tabs., figs.

  2. Canadian Landsat studies for monitoring resource development: A summary

    Science.gov (United States)

    Bonn, F. J.; Howarth, P. J.

    This report summarizes a major paper reviewing Canadian work using Landsat imagery for monitoring the environmental effects of the development of both renewable and non-renewable resources. Landsat has definite advantages for studying resources. In particular, the data are able to show changes in surface cover indicating in many cases development or the exploitation of resources. Monitoring of areas and rates of change over time is possible. Outlined in the paper are examples related to three aspects of resource development. First is the use of Landsat for updating topographic maps for areas where recent developments have taken place. The second aspect is forestry, and examples related to the detection and measurement of clear cuts and recording of areas affected by spruce budworm are reported. Finally, studies of landscape changes produced by mining activities are presented.

  3. A three-year field validation study to improve the integrated pest management of hot pepper.

    Science.gov (United States)

    Kim, Ji-Hoon; Yun, Sung-Chul

    2013-09-01

    To improve the integrated pest management (IPM) of hot pepper, field study was conducted in Hwasung from 2010 to 2012 and an IPM system was developed to help growers decide when to apply pesticides to control anthracnose, tobacco budworm, Phytophthora blight, bacterial wilt, and bacterial leaf spot. The three field treatments consisted of IPM sprays following the forecast model advisory, a periodic spray at 7-to-10-day intervals, and no spray (control). The number of annual pesticide applications for the IPM treatment ranged from six to eight, whereas the plots subjected to the periodic treatment received pesticide 11 or 12 times annually for three years. Compared to the former strategy, our improved IPM strategy features more intense pest management, with frequent spraying for anthracnose and mixed spraying for tobacco budworm or Phytophthora blight. The incidences for no pesticide control in 2010, 2011, and 2012 were 91, 97.6, and 41.4%, respectively. Conversely, the incidences for the IPM treatment for those years were 7.6, 62.6, and 2%, and the yields from IPM-treated plots were 48.6 kg, 12.1 kg, and 48.8 kg. The incidence and yield in the IPM-treated plots were almost the same as those of the periodic treatment except in 2011, in which no unnecessary sprays were given, meaning that the IPM control was quite successful. From reviewing eight years of field work, sophisticated forecasts that optimize pesticide spray timing reveal that reliance on pesticides can be reduced without compromising yield. Eco-friendly strategies can be implemented in the pest management of hot pepper. PMID:25288956

  4. A Three-Year Field Validation Study to Improve the Integrated Pest Management of Hot Pepper

    Directory of Open Access Journals (Sweden)

    Ji-Hoon Kim

    2013-09-01

    Full Text Available To improve the integrated pest management (IPM of hot pepper, field study was conducted in Hwasung from 2010 to 2012 and an IPM system was developed to help growers decide when to apply pesticides to control anthracnose, tobacco budworm, Phytophthora blight, bacterial wilt, and bacterial leaf spot. The three field treatments consisted of IPM sprays following the forecast model advisory, a periodic spray at 7-to-10-day intervals, and no spray (control. The number of annual pesticide applications for the IPM treatment ranged from six to eight, whereas the plots subjected to the periodic treatment received pesticide 11 or 12 times annually for three years. Compared to the former strategy, our improved IPM strategy features more intense pest management, with frequent spraying for anthracnose and mixed spraying for tobacco budworm or Phytophthora blight. The incidences for no pesticide control in 2010, 2011, and 2012 were 91, 97.6, and 41.4%, respectively. Conversely, the incidences for the IPM treatment for those years were 7.6, 62.6, and 2%, and the yields from IPM-treated plots were 48.6 kg, 12.1 kg, and 48.8 kg. The incidence and yield in the IPM-treated plots were almost the same as those of the periodic treatment except in 2011, in which no unnecessary sprays were given, meaning that the IPM control was quite successful. From reviewing eight years of field work, sophisticated forecasts that optimize pesticide spray timing reveal that reliance on pesticides can be reduced without compromising yield. Eco-friendly strategies can be implemented in the pest management of hot pepper.

  5. Development and Integration of Alternative Management Strategies Using Inherited Sterility and Natural Enemies to Control Lepidopteran Pests

    International Nuclear Information System (INIS)

    Lepidopteran pests such as corn earworm, Helicoverpa zea, fall armyworm, Spodoptera frugiperda, beet armyworm, Spodoptera exigua, and diamondback moth, Plutella xylostella, are often the most destructive pests of field crops in the United States. Insecticide resistance, increasing concern over pesticide pollution, and the desire to effectively manage lepidopteran pests on an area-wide basis have motivated scientists to identify and develop new pest management tactics that are compatible with current IPM practices. IPM-based systems, including genetic methods and biological control, offer the best long-term solutions to pesticide reduction and the management of destructive agricultural pests. F1 sterility has emerged as a promising control strategy for lepidopteran pests.

  6. Introgression of Bt Genes in Novel Germplasm and Contribution to Indian Cotton Economy

    Institute of Scientific and Technical Information of China (English)

    VIDYASAGAR Parchuri

    2008-01-01

    @@ Emergence of transgenic Bt-cotton technology has opened up a new chapter in Indian cotton production in 21st century.The crylAc gene of Monsanto derived from American Upland Coker-312 background was not directly suitable for varied cotton growing situations in India.Delivery of Bt-gene technology to Indian farming systems should be superimposed on hybrid technology,fiber quality,and superior agronomic adaptation.Protection offered by this alien Bt-gene against major serious pest Helicoverpa armigera,by preventing annual losses ranging from 15~35 percent,automaticaly contributed to higher yield.

  7. Recurrent selection for corn earworm resistance in three corn synthetics.

    OpenAIRE

    Butrón Gómez, Ana María; Widstrom, N. W.; Snook, M E; Wiseman, B. R.

    2000-01-01

    Corn (Zea mays L.) grown in the Southeastern U. S. is often severely damaged by corn earworm (Helicoverpa zea Boddie), which feed on developing kernels on the ear. Natural resistance to this insect due to husk cover and chemicals in the silks has been identified. we studied the improvement in the resistance to ear injury by the corn earworm in the population 10LDDSR after 10 cycles of S1 recurrent selection and in the population cross DDSA x DDSB after seven cycles of reciprocal recurrent sel...

  8. Eficácia do indoxacarb para o controle de pragas em hortaliças

    OpenAIRE

    Martinelli Samuel; Montagna Marco Aurélio; Picinato Nilton César; Silva Fábio M.A.; Fernandes Odair Aparecido

    2003-01-01

    A eficiência do indoxacarb foi avaliada no controle dos lepidópteros-pragas em hortaliças: Plutella xylostella (Lepidoptera: Yponeumatidae), Trichoplusia ni (Lepidoptera: Noctuidae), Neoleucinodes elegantalis (Lepidoptera: Pyralidae) e Helicoverpa zea (Lepidoptera: Noctuidae). Os experimentos foram conduzidos em três locais diferentes nas culturas do repolho e tomate. Os inseticidas utilizados foram indoxacarb (no tomate de 2,4 a 6,0 g i.a./100 L e no repolho de 18 a 42 g i.a./ha), esfenvaler...

  9. Inseticidas para o controle da traça-do-tomateiro e broca-grande e seu impacto sobre Trichogramma pretiosum Insecticides for the control of the South American tomato pinworm and the corn earworm and impact of those products on Trichogramma pretiosum

    OpenAIRE

    Marina Castelo Branco; Ludimilla A. Pontes; Pablo S.T. Amaral; Manoel V. Mesquita Filho

    2003-01-01

    Experimentos de campo foram conduzidos entre maio e outubro de 2000 para determinar a eficiência de diversos inseticidas para o controle de Tuta absoluta e Helicoverpa zea e o impacto desses produtos sobre a emergência do parasitóide Trichogramma pretiosum. Os inseticidas testados, bem como as doses em g i.a./ha foram: metoxifenozide (120; 144), clorpirifós (540; 675), tiacloprid (72; 96) e triflumuron (144). O delineamento experimental foi de blocos ao acaso com oito tratamentos (inseticidas...

  10. Eficácia do indoxacarb para o controle de pragas em hortaliças Efficacy of indoxacarb in the control of vegetable pests

    OpenAIRE

    Samuel Martinelli; Marco Aurélio Montagna; Nilton César Picinato; Fábio M.A. Silva; Odair Aparecido Fernandes

    2003-01-01

    A eficiência do indoxacarb foi avaliada no controle dos lepidópteros-pragas em hortaliças: Plutella xylostella (Lepidoptera: Yponeumatidae), Trichoplusia ni (Lepidoptera: Noctuidae), Neoleucinodes elegantalis (Lepidoptera: Pyralidae) e Helicoverpa zea (Lepidoptera: Noctuidae). Os experimentos foram conduzidos em três locais diferentes nas culturas do repolho e tomate. Os inseticidas utilizados foram indoxacarb (no tomate de 2,4 a 6,0 g i.a./100 L e no repolho de 18 a 42 g i.a./ha), esfenvaler...

  11. Bio-potency of a 21 kDa Kunitz-type trypsin inhibitor from Tamarindus indica seeds on the developmental physiology of H. armigera.

    Science.gov (United States)

    Pandey, Prabhash K; Jamal, Farrukh

    2014-11-01

    A trypsin inhibitor purified from the seeds of Tamarindus indica by Sephadex G-75, DEAE-Sepharose and Trypsin-Sepharose CL-4B columns was studied for its antifeedant, larvicidal, pupicidal and growth inhibitory activities against Helicoverpa armigera larvae. Tamarindus trypsin inhibitor (TTI) exhibited inhibitory activity towards total gut proteolytic enzymes of H. armigera (~87%) and bovine trypsin (~84%). Lethal doses which caused mortality and weight reduction by 50% were 1% w/w and 0.50% w/w, respectively. IC50 of TTI against Helicoverpa midgut proteases and bovine trypsin were ~2.10 µg/ml and 1.68 µg/ml respectively. In larval feeding studies the 21 kDa Kunitz-type protein was found to retard growth and development, prolonged the larval-pupal development durations along with adversely affecting the fertility and fecundity of H. armigera. In artificial diet at 0.5% w/w TTI, the efficiency of conversion of ingested food as well as of digested food, relative growth rate, growth index declined whereas approximate digestibility, metabolic cost, relative consumption rate, consumption index and total developmental period enhanced for H. armigera larvae. These results suggest that TTI has toxic and adverse effect on the developmental physiology of H. armigera and could be useful in controlling the pest H. armigera.

  12. Cloning and characterization of an insecticidal crystal protein gene from Bacillus thuringiensis subspecies kenyae

    Indian Academy of Sciences (India)

    Hari S. Misra; Nivedita P. Khairnar; Manjula Mathur; N. Vijayalakshmi; Remesh S. Hire; T. K. Dongre; S. K. Mahajan

    2002-04-01

    A sporulating culture of Bacillus thuringiensis subsp. kenyae strain HD549 is toxic to larvae of lepidopteran insect species such as Spodoptera litura, Helicoverpa armigera and Phthorimaea operculella, and a dipteran insect, Culex fatigans. A 1.9-kb DNA fragment, PCR-amplified from HD549 using cryII-gene-specific primers, was cloned and expressed in E. coli. The recombinant protein produced 92% mortality in first-instar larvae of Spodoptera litura and 86% inhibition of adult emergence in Phthorimaea operculella, but showed very low toxicity against Helicoverpa armigera, and lower mortality against third-instar larvae of dipteran insects Culex fatigans, Anopheles stephensi and Aedes aegypti. The sequence of the cloned crystal protein gene showed almost complete homology with a mosquitocidal toxin gene from Bacillus thuringiensis var. kurstaki, with only five mutations scattered in different regions. Amino acid alignment with different insecticidal crystal proteins using the MUTALIN program suggested presence of the conserved block 3 region in the sequence of this protein. A mutation in codon 409 of this gene that changes a highly conserved phenylalanine residue to serine lies in this block.

  13. Cloning and characterization of an insecticidal crystal protein gene from Bacillus thuringiensis subspecies kenyae.

    Science.gov (United States)

    Misra, Hari S; Khairnar, Nivedita P; Mathur, Manjula; Vijayalakshmi, N; Hire, Ramesh S; Dongre, T K; Mahajan, S K

    2002-04-01

    A sporulating culture of Bacillus thuringiensis subsp. kenyae strain HD549 is toxic to larvae of lepidopteran insect species such as Spodoptera litura, Helicoverpa armigera and Phthorimaea operculella, and a dipteran insect, Culex fatigans. A 1.9-kb DNA fragment, PCR-amplified from HD549 using cryII-gene-specific primers, was cloned and expressed in E. coli. The recombinant protein produced 92% mortality in first-instar larvae of Spodoptera litura and 86% inhibition of adult emergence in Phthorimaea operculella, but showed very low toxicity against Helicoverpa armigera, and lower mortality against third-instar larvae of dipteran insects Culex fatigans, Anopheles stephensi and Aedes aegypti. The sequence of the cloned crystal protein gene showed almost complete homology with a mosquitocidal toxin gene from Bacillus thuringiensis var. kurstaki, with only five mutations scattered in different regions. Amino acid alignment with different insecticidal crystal proteins using the MUTALIN program suggested presence of the conserved block 3 region in the sequence of this protein. A mutation in codon 409 of this gene that changes a highly conserved phenylalanine residue to serine lies in this block. PMID:12357073

  14. Phytopesticidal effects of Spilanthes acmella (L.) Murr. leaves on three economically important lepidopteran insect pests

    Institute of Scientific and Technical Information of China (English)

    Manickam Pavunraj; Kathirvelu Baskar; Sundaram Janarthanan; Munusamy Arumugam

    2014-01-01

    Objective: To evaluate the antifeedant and larvicidal activities of dichloromethane (DCM), acetone, dimethylsulfoxide (DMSO) and aqueous extracts of Spilanthes acmella (S. acmella) leaves against Earias vitella, Helicoverpa armigera and Spodoptera litura.Methods:DCM, acetone, DMSO and aqueous extracts were studied using fruit and leaf discs no-choice method at 0.625%, 1.25%, 2.5% and 5% concentration. Results: All the extracts showed antifeedant and larvicidal activities against all the tested insects. However, maximum antifeedant activity was detected in DCM extract of S. acmella against all tested pest, followed by acetone, DMSO and aqueous extracts at 5% concentration. The leaves extract of S. acmella also showed larvicidal activity; maximum larval mortality was observed in DCM extract against Helicoverpa armigera (48.88%), Spodoptera litura (44.88%) and Earias vitella (75.11%) followed by acetone, DMSO and aqueous extracts at 5% concentration.Conclusions:DCM extract of S. acmella could be further purified to develop a formulation for eco-friendly pest control agent.

  15. Effects of methoxyfenozide, indoxacarb, and other insecticides on the beneficial egg parasitoid Trichogramma nr. brassicae (Hymenoptera: Trichogrammatidae) under laboratory and field conditions.

    Science.gov (United States)

    Hewa-Kapuge, Swarna; McDougall, Sandra; Hoffmann, Ary A

    2003-08-01

    Trichogramma nr. brassicae is a common egg parasitoid of Helicoverpa species in Australian processing tomatoes, but its effectiveness can be severely curtailed by insecticide applications. To identify insecticides that are potentially compatible with this species, the effects of seven insecticides, including newly introduced compounds and a surfactant, were screened in laboratory and glasshouse assays for their toxicity to the wasps. Assays involved direct applications on adults, residual effects on adults, and applications on life stages still inside the host. Methoxyfenozide and indoxacarb were not toxic to Trichogramma in any assay when applied at field rates. Naled and chlorfenapyr caused 100% mortality when directly applied to adults, and 95% mortality when adults were exposed to residues of these chemicals within 24 h of application. The effects of naled residues were short lived (Naled and chlorfenapyr were also toxic when applied to Trichogramma developing inside host eggs, reducing emergence of adults by >25%. Imidacloprid, emamectin, and tau-fluvalinate were toxic in some experiments; they caused >97% mortality in adults 1 h after direct application and in residue assays they caused 23-64% mortality during the first 24 h. In field trials, methoxyfenozide had no harmful effects on emergence from sprayed parasitized eggs, whereas indoxacarb had a small impact (<8%) on emergence. Methoxyfenozide and indoxacarb are potentially suitable for inclusion in integrated pest management strategies for management of Helicoverpa because they do not influence adult survival or development of immature stages, whereas other chemicals need to be treated cautiously. PMID:14503578

  16. Cell Culture for Production of Insecticidal Viruses.

    Science.gov (United States)

    Reid, Steven; Chan, Leslie C L; Matindoost, Leila; Pushparajan, Charlotte; Visnovsky, Gabriel

    2016-01-01

    While large-scale culture of insect cells will need to be conducted using bioreactors up to 10,000 l scale, many of the main challenges for cell culture-based production of insecticidal viruses can be studied using small-scale (20-500 ml) shaker/spinner flasks, either in free suspension or using microcarrier-based systems. These challenges still relate to the development of appropriate cell lines, stability of virus strains in culture, enhancing virus yields per cell, and the development of serum-free media and feeds for the desired production systems. Hence this chapter presents mainly the methods required to work with and analyze effectively insect cell systems using small-scale cultures. Outlined are procedures for quantifying cells and virus and for establishing frozen cells and virus stocks. The approach for maintaining cell cultures and the multiplicity of infection (MOI) and time of infection (TOI) parameters that should be considered for conducting infections are discussed.The methods described relate, in particular, to the suspension culture of Helicoverpa zea and Spodoptera frugiperda cell lines to produce the baculoviruses Helicoverpa armigera nucleopolyhedrovirus, HearNPV, and Anticarsia gemmatalis multicapsid nucleopolyhedrovirus, AgMNPV, respectively, and the production of the nonoccluded Oryctes nudivirus, OrNV, using an adherent coleopteran cell line. PMID:27565495

  17. Effects of transgenic Cry1A+CpTI cotton and Cry1Ac toxin on the parasitoid, Campoketis chlorideae (Hymenoptera:Ichneumonidae)

    Institute of Scientific and Technical Information of China (English)

    XIAO-XIALIU; CHANG-GUISUN; QING-WENZHANG

    2005-01-01

    The effect oftransgenic double genes, Cry1A + CpTlcotton and Cry1Ac toxin on the parasitoid, Carnpoketis chlorideae Uchida of cotton bollworm, Helicoverpa armigera (Hübner), was investigated in the laboratory. Helicoverpa armigera larvae when in the first,second and third instar could not survive if fed on transgenic cotton leaves. Consequently,C. chlorideae larvae could not complete their development if parasitizing on such hosts.After H. armigera larvae were reared on transgenic or traditional cotton leaves for 12-48 hours, they were parasitized by C. chlorideae females. Parasitized larvae continued to feed on transgenic or traditional cotton for 12-48 h. The present results showed that the body weight of larvae of the parasitoids were significantly reduced when parasitized hosts fed on transgenic cotton leaves compared to those fed on traditional cotton. Duration of egg and larvae stage were significantly prolonged, pupal and adult weight of C. chloridae was decreased when the host larvae fed on transgenic cotton leaves longer than 48 h. The development duration of C. chlorideae pupae on the hosts fed on transgenic cotton leaves in each treatment was not significantly different from those of controls. The longevity of parasitoid females and males fed with a solution containing Cry1Ac toxin was not significantly different with that of the control.

  18. Monitoring Carbon Fluxes from Shallow Surface Soils in the Critical Zone

    Science.gov (United States)

    Stielstra, C. M.; Brooks, P. D.; Chorover, J.

    2011-12-01

    The critical zone (CZ) is the earth's porous near-surface layer, characterized by the integrated processes that occur between the bedrock and the atmospheric boundary layer. Within this area water, atmosphere, ecosystems, and soils interact on a geomorphic and geologic template. We hypothesize that CZ systems organize and evolve in response to open system fluxes of energy and mass, including meteoric inputs of radiation, water, and carbon, which can be quantified at point to watershed scales. The goal of this study is to link above-ground and below-ground carbon processes by quantifying carbon pools and fluxes from near surface soils. Soil CO2 efflux and dissolved organic carbon (DOC) are monitored over a two year period across bedrock type and vegetation type at two seasonally snow covered subalpine catchments in Arizona and New Mexico. We measure the amount of DOC present in surface soils, and install ion exchange resins at the A/B soil horizon interface to capture DOC leachate mobilized during snowmelt and summer rainfall. Throughout the summer rain and spring snowmelt seasons we monitor soil respiration of CO2. Preliminary results show that rates of gaseous carbon flux are significantly higher (psoils with schist bedrock (2.5 ± 0.2 gC/m2/d )than from granite bedrock (1.3 ± 0.1 gC/m2/d), and higher from healthy mixed conifer forests (1.9 ± 0.3 gC/m2/d) than from mixed conifer forests impacted by spruce budworm (1.4 ± 0.1 gC/m2/d). DOC leached from soil samples does not vary significantly with bedrock type; however, spruce budworm impacted forests have significantly higher levels of leachable DOC in surface soils (22.8 ± 4.5 gC/m2) than are found in the soils of healthy forests (10.0 ± 1.5 gC/m2) or subalpine meadows (9.1 ± 0.5 gC/m2). The results of this study will allow us to evaluate the variability of carbon fluxes with vegetation and soil type within a shallow soil carbon pool and help constrain the contributions of soil organic carbon to net carbon

  19. Barcoding a quantified food web: crypsis, concepts, ecology and hypotheses.

    Directory of Open Access Journals (Sweden)

    M Alex Smith

    Full Text Available The efficient and effective monitoring of individuals and populations is critically dependent on correct species identification. While this point may seem obvious, identifying the majority of the more than 100 natural enemies involved in the spruce budworm (Choristoneura fumiferana--SBW food web remains a non-trivial endeavor. Insect parasitoids play a major role in the processes governing the population dynamics of SBW throughout eastern North America. However, these species are at the leading edge of the taxonomic impediment and integrating standardized identification capacity into existing field programs would provide clear benefits. We asked to what extent DNA barcoding the SBW food web would alter our understanding of the diversity and connectence of the food web and the frequency of generalists vs. specialists in different forest habitats. We DNA barcoded over 10% of the insects collected from the SBW food web in three New Brunswick forest plots from 1983 to 1993. For 30% of these specimens, we amplified at least one additional nuclear region. When the nodes of the food web were estimated based on barcode divergences (using molecular operational taxonomic units (MOTU or phylogenetic diversity (PD--the food web became much more diverse and connectence was reduced. We tested one measure of food web structure (the "bird feeder effect" and found no difference compared to the morphologically based predictions. Many, but not all, of the presumably polyphagous parasitoids now appear to be morphologically-cryptic host-specialists. To our knowledge, this project is the first to barcode a food web in which interactions have already been well-documented and described in space, time and abundance. It is poised to be a system in which field-based methods permit the identification capacity required by forestry scientists. Food web barcoding provided an effective tool for the accurate identification of all species involved in the cascading effects of

  20. The nicotinic acetylcholine receptor gene family of the malaria mosquito, Anopheles gambiae.

    Science.gov (United States)

    Jones, Andrew K; Grauso, Marta; Sattelle, David B

    2005-02-01

    Nicotinic acetylcholine receptors (nAChRs) mediate fast cholinergic synaptic transmission in the insect nervous system and are targets of widely selling insecticides. We have identified the nAChR gene family from the genome of the malaria mosquito vector, Anopheles gambiae, to be the second complete insect nAChR gene family described following that of Drosophila melanogaster. Like Drosophila, Anopheles possesses 10 nAChR subunits with orthologous relationships evident between the two insects. Interestingly, the Anopheles orthologues of Dbeta2 and Dbeta3 possess the vicinal cysteines that define alpha subunits. As with Dalpha4 and Dalpha6, the Anopheles orthologues are alternatively spliced at equivalent exons. Reverse transcription-polymerase chain reaction analysis shows that RNA A-to-I editing sites conserved between Dalpha6 of Drosophila and alpha7-2 of the tobacco budworm, Heliothis virescens, are not shared with the equivalent nAChR subunit of Anopheles. Indeed, RNA-editing sites identified in functionally significant regions of Dbeta1, Dalpha5, and Dalpha6 are not conserved in the mosquito orthologues, indicating considerable divergence of RNA molecules targeted for editing within the insect order Diptera. These findings shed further light on the diversity of nAChR subunits and may present a useful basis for the development of improved malaria control agents by enhancing our understanding of a validated mosquito insecticide target.

  1. Insect radiosensitivity: dose curves and dose-fractionation studies of dominant lethal mutations in the mature sperm of 4 insect species

    Energy Technology Data Exchange (ETDEWEB)

    LaChance, L.E.; Graham, C.K. (Department of Agriculture, Fargo, ND (USA))

    1984-06-01

    Males of 4 species of insects: Musca domestica L. (housefly) (Diptera), Oncopeltus fasciatus (Dallas) (milkweed bug) (Hemiptera), Anagasta kuhniella (Zeller) (mealmoth) (Lepidoptera) and Heliothis virescens (Fab.) (tobacco budworm) (Lepidoptera) were irradiated as adults. Dose-response curves for the induction of dominant lethal mutations in the mature sperm were constructed. The curves were analyzed mathematically and compared with theoretical computer simulated curves requiring 1, 2, 4, 8 and 16 'hits' for the induction of a dominant lethal mutation. The 4 species belonging to 3 different orders of insects showed a wide range in radiation sensitivity and vastly different dose-response curves. When the data were analyzed by several mathematical models the authors found that a logistic response curve gave reasonably good fit with vastly different parameters for the 4 species. Dose-fractionation experiments showed no reduction in the frequency of lethal mutations induced in any species when an acute dose was fractionated into 2 equal exposures separated by an 8-h period.

  2. A single gene (yes controls pigmentation of eyes and scales in Heliothis virescens

    Directory of Open Access Journals (Sweden)

    Thomas M. Brown

    2001-02-01

    Full Text Available A yellow-eyed mutant was discovered in a strain of Heliothis virescens, the tobacco budworm, that already exhibited a mutation for yellow scale, y. We investigated the inheritance of these visible mutations as candidate markers for transgenesis. Yellow eye was controlled by a single, recessive, autosomal factor, the same type of inheritance previously known for y. Presence of the recombinant mutants with yellow scales with wild type eyes in test crosses indicated independent segregation of genes for these traits. The recombinant class with wild type scales and yellow eyes was completely absent and there was a corresponding increase of the double mutant parental class having yellow scales and yellow eyes. These results indicated that a single factor for yellow eye also controls yellow scales independently of y. This gene was named yes, for yellow eye and scale. We hypothesize that yes controls both eye and scale color through a deficiency in transport of pigment precursors in both the ommochrome and melanin pathways. The unlinked gene y likely controls an enzyme affecting the melanin pathway only. Both y and yes segregated independently of AceIn, acetylcholinesterase insensitivity, and sodium channel hscp, which are genes related to insecticide resistance.

  3. Structural, Electronic and Qsar Properties of the Cyfluthrin Molecule:. a Theoretical AM1 and PM3 Treatment

    Science.gov (United States)

    Çalişir, Emine Deniz; Erkoç, Şakir

    Cyfluthrin is a synthetic cyano-containing pyrethroid insecticide that has both contact and stomach poison action. It is a nonsystemic chemical used to control cutworms, ants, silverfish, cockroaches, mosquitoes, tobacco budworm and many others. Its primary agricultural uses have been for control of chewing and sucking insects on crops such as cotton, turf, ornamentals, hops, cereal, corn, deciduous fruit, peanuts, potatoes, and other vegetables. Cyfluthrin is also used in public health situations and for structural pest control. The structural, vibrational, electronic and QSAR properties of the cyfluthrin molecule in gas phase have been investigated theoretically by performing molecular mechanics method by using MM+ force field, and semi-empirical molecular orbital AM1 and PM3 calculations. The geometry of the molecule has been optimized, infrared spectrum (vibrational modes and intensities) and the electronic properties of the molecule have been calculated in its ground state. According to PM3 calculation, heat of formation of cyfluthrin molecule is about -48.58 kcal/mol (exothermic), which shows that this molecule thermodynamically be stable. The HOMO energy level for this molecule is found to be -9.701 eV and the LUMO energy level is -0.660 eV giving rise to a gap of 9.041 eV, which also indicates that cyfluthrin is thermodynamically stable.

  4. Growth Response of Northern White-Cedar (Thuja occidentalis to Natural Disturbances and Partial Cuts in Mixedwood Stands of Quebec, Canada

    Directory of Open Access Journals (Sweden)

    Jean-Claude Ruel

    2014-05-01

    Full Text Available Northern white-cedar (Thuja occidentalis is a species of high commercial and ecological value, the abundance of which has been declining since the middle of the 19th century. Very little information regarding its silviculture in mixedwood stands is currently available, even though a significant portion of wood resources comes from these stands. The present study is a retrospective analysis of white-cedar growth in partially harvested mixedwood stands of western Quebec, Canada. Eight stands distributed across two regions were analyzed. Dendrochronological approaches examined long-term diameter growth for sample white-cedar trees and stems of associated species. These approaches were used to reconstruct stand characteristics at the time of harvesting, together with local harvesting intensity. The study demonstrated white-cedar’s capacity to maintain good growth for long periods of time and at large tree sizes. Accession to the upper canopy positions occurs through repeated episodes of suppression/release, most of which seem to be associated with spruce budworm (Choristoneura fumiferana outbreaks. White-cedar response to partial harvesting varies with tree size, residual basal area and species composition. Growth response was generally stronger for small trees, even though large trees still maintained the best diameter growth. Growth of white-cedar was negatively affected by an increase in softwood proportion in basal area. Growth responses to harvesting could be sustained for a period of 20 years.

  5. The role of analytical science in natural resource decision making

    Science.gov (United States)

    Miller, Alan

    1993-09-01

    There is a continuing debate about the proper role of analytical (positivist) science in natural resource decision making. Two diametrically opposed views are evident, arguing for and against a more extended role for scientific information. The debate takes on a different complexion if one recognizes that certain kinds of problem, referred to here as “wicked” or “trans-science” problems, may not be amenable to the analytical process. Indeed, the mistaken application of analytical methods to trans-science problems may not only be a waste of time and money but also serve to hinder policy development. Since many environmental issues are trans-science in nature, then it follows that alternatives to analytical science need to be developed. In this article, the issues involved in the debate are clarified by examining the impact of the use of analytical methods in a particular case, the spruce budworm controversy in New Brunswick. The article ends with some suggestions about a “holistic” approach to the problem.

  6. RNA-Seq Study of Microbially Induced Hemocyte Transcripts from Larval Heliothis virescens (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Kent S. Shelby

    2012-08-01

    Full Text Available Larvae of the tobacco budworm are major polyphagous pests throughout the Americas. Development of effective microbial biopesticides for this and related noctuid pests has been stymied by the natural resistance mediated innate immune response. Hemocytes play an early and central role in activating and coordinating immune responses to entomopathogens. To approach this problem we completed RNA-seq expression profiling of hemocytes collected from larvae following an in vivo challenge with bacterial and fungal cell wall components to elicit an immune response. A de novo exome assembly was constructed by combination of sequence tags from all treatments. Sequence tags from each treatment were aligned separately with the assembly to measure expression. The resulting table of differential expression had > 22,000 assemblies each with a distinct combination of annotation and expression. Within these assemblies > 1,400 were upregulated and > 1,500 downregulated by immune activation with bacteria or fungi. Orthologs to innate immune components of other insects were identified including pattern recognition, signal transduction pathways, antimicrobial peptides and enzymes, melanization and coagulation. Additionally orthologs of components regulating hemocytic functions such as autophagy, apoptosis, phagocytosis and nodulation were identified. Associated cellular oxidative defenses and detoxification responses were identified providing a comprehensive snapshot of the early response to elicitation.

  7. Understanding heliothine (Lepidoptera: Heliothinae) pests: what is a host plant?

    Science.gov (United States)

    Cunningham, John Paul; Zalucki, Myron P

    2014-06-01

    Heliothine moths (Lepidoptera: Heliothinae) include some of the world's most devastating pest species. Whereas the majority of nonpest heliothinae specialize on a single plant family, genus, or species, pest species are highly polyphagous, with populations often escalating in size as they move from one crop species to another. Here, we examine the current literature on heliothine host-selection behavior with the aim of providing a knowledge base for research scientists and pest managers. We review the host relations of pest heliothines, with a particular focus on Helicoverpa armigera (Hübner), the most economically damaging of all heliothine species. We then consider the important question of what constitutes a host plant in these moths, and some of the problems that arise when trying to determine host plant status from empirical studies on host use. The top six host plant families in the two main Australian pest species (H. armigera and Helicoverpa punctigera Wallengren) are the same and the top three (Asteraceae, Fabaceae, and Malvaceae) are ranked the same (in terms of the number of host species on which eggs or larvae have been identified), suggesting that these species may use similar cues to identify their hosts. In contrast, for the two key pest heliothines in the Americas, the Fabaceae contains approximately 1/3 of hosts for both. For Helicoverpa zea (Boddie), the remaining hosts are more evenly distributed, with Solanaceae next, followed by Poaceae, Asteraceae, Malvaceae, and Rosaceae. For Heliothis virescens (F.), the next highest five families are Malvaceae, Asteraceae, Solanaceae, Convolvulaceae, and Scrophulariaceae. Again there is considerable overlap in host use at generic and even species level. H. armigera is the most widely distributed and recorded from 68 plant families worldwide, but only 14 families are recorded as a containing a host in all geographic areas. A few crop hosts are used throughout the range as expected, but in some cases there

  8. Nucleopolyhedrovirus Introduction in Australia

    Institute of Scientific and Technical Information of China (English)

    Patrick Buerger; Caroline Hauxwell; David Murray

    2007-01-01

    Nucleopolyhedrovirus (NPV) has become an integral part of integrated pest management (IPM) in many Australian agricultural and horticultural crops. This is the culmination of years of work conducted by researchers at the Queensland Department of Primary Industries and Fisheries (QDPI&F) and Ag Biotech Australia Pty Ltd. In the early 1970's researchers at QDPI&F identified and isolated a virus in Helicoverpa armigera populations in the field. This NPV was extensively studied and shown to be highly specific to Helicoverpa and Heliothis species. Further work showed that when used appropriately the virus could be used effectively to manage these insects in crops such as sorghum, cotton, chickpea and sweet corn. A similar virus was first commercially produced in the USA in the 1970's. This product, Elcar(R), was introduced into Australia in the late 1970's by Shell Chemicals with limited success. A major factor contributing to the poor adoption of Elcar was the concurrent enormous success of the synthetic pyrethroids. The importance of integrated pest management was probably also not widely accepted at that time. Gradual development of insect resistance to synthetic pyrethroids and other synthetic insecticides in Australia and the increased awareness of the importance of IPM meant that researchers once again turned their attentions to environmentally friendly pest management tools such NPV and beneficial insects. In the 1990's a company called Rhone-Poulenc registered an NPV for use in Australian sorghum, chickpea and cotton. This product, Gemstar(R), was imported from the USA. In 2000 Ag Biotech Australia established an in-vivo production facility in Australia to produce commercial volumes of a product similar to the imported product. This product was branded, ViVUS(R), and was first registered and sold commercially in Australia in 2003. The initial production of ViVUS used a virus identical to the American product but replicating it in an Australian Helicoverpa

  9. Preliminary studies on differential defense responses induced during plant communication

    Institute of Scientific and Technical Information of China (English)

    Jin Ying PENG; Zhong Hai LI; Hui XIANG; Jian Hua HUANG; Shi Hai JIA; Xue Xia MIAO; Yong Ping HUANG

    2005-01-01

    We compared the expression patterns of three representative genes in undamaged tomato and tobacco plants in response to exposure to either tomato or tobacco fed on by Helicoverpa armigera (cotton bollworm). When tomato and tobacco, two species of one family, were incubated in the chambers with the tomato plants damaged by the cotton bollworm, the expression of the PR1, BGL2, and PAL genes was up-regulated in leaves of both plants. However, the levels of gene expression were significantly higher in the tomato than that in the tobacco. In addition, the activities of enzymes, peroxidase, polyphenol oxidase, and lipoxygenase were found to be higher in the tomato than those in the tobacco. Similar results were obtained when the damaged plants were replaced by the tobacco.

  10. A Survey of the Insect Pests and Farmers' Practices in the Cropping of Tomato in Nigeria

    Directory of Open Access Journals (Sweden)

    Umeh, VC.

    2002-01-01

    Full Text Available A survey of some tomato producing areas of Nigeria indicated that the major insects attacking tomato included the fruit borer Helicoverpa armigera Hübner, the grasshopper Zonocerus variegatus L., the whitefly Bemisia tabacci Gennadius, and various species of aphids, mostly Aphis gossypii Glover. Interviews conducted to assess farmers' practices which contribute to insect damage showed that inappropriate application of insecticides and the use of wrong dosages may have contributed to insect control failures. Intercropping tomato with crops such as cereals tubers and other vegetables reduced infestation in some areas. However, most farmers' practices did not affect insect pest abundance. Insect populations and percentages of infestation were, in most cases, found to be significantly higher in Oyo state (in the rain forest agro-ecological zone than in other surveyed states located in the savannah agro-ecological zones.

  11. Biological characteristics of Bacillus thuringiensis strain Btll and identification of its cry-type genes

    Institute of Scientific and Technical Information of China (English)

    Tinghui LIU; Wei GUO; Weiming SUN; Yongxiang SUN

    2009-01-01

    A novel strain of Bacillus thuringiensis Bt11, isolated from soil samples in China, was classified and characterized in terms of its crystal proteins, cry genes content. The Bt11 strain showed high toxicity against Spodoptera exigua and Helicoverpa armigera neonates. Btll strain shares morphological and biochemical characteristics with the previously described Bacillus thuringiensis subsp. kurstaki. SDS-polyacrylamide gel electrophoresis revealed that crystals were composed of several polypeptides ranging from 20 to 130 kDa, of which the 35, 80, and 130 kDa proteins were the major components. PCR-RFLP with total DNA from strain Btll and specific primers for cryl, cry2, cry3, cry4/10, cry7, cry8, cry9, and cryll genes revealed that crylAa, crylAb, crylla, and cry9Ea genes were present.

  12. A multisensory centrifugal neuron in the olfactory pathway of heliothine moths

    DEFF Research Database (Denmark)

    Zhao, Xin-Cheng; Pfuhl, Gerit; Surlykke, Annemarie;

    2013-01-01

    We have characterized, by intracellular recording and staining, a unique type of centrifugal neuron in the brain olfactory center of two heliothine moth species; one in Heliothis virescens and one in Helicoverpa armigera. This unilateral neuron, which is not previously described in any moth, has...... fine processes in the dorsomedial region of the protocerebrum and extensive neuronal branches with blebby terminals in all glomeruli of the antennal lobe. Its soma is located dorsally of the central body close to the brain midline. Mass-fills of antennal-lobe connections with protocerebral regions...... showed that the centrifugal neuron is, in each brain hemisphere, one within a small group of neurons having their somata clustered. In both species the neuron was excited during application of non-odorant airborne signals, including transient sound pulses of broad bandwidth and air velocity changes...

  13. Design, Synthesis and Insecticidal Activity of Novel Phenylurea Derivatives

    Directory of Open Access Journals (Sweden)

    Jialong Sun

    2015-03-01

    Full Text Available A series of novel phenylurea derivatives were designed and synthesized according to the method of active groups linkage and the principle of aromatic groups bioisosterism in this study. The structures of the novel phenylurea derivatives were confirmed based on ESI-MS, IR and 1H-NMR spectral data. All of the compounds were evaluated for the insecticidal activity against the third instars larvae of Spodoptera exigua Hiibner, Plutella xyllostella Linnaeus, Helicoverpa armigera Hubner and Pieris rapae Linne respectively, at the concentration of 10 mg/L. The results showed that all of the derivatives displayed strong insecticidal activity. Most of the compounds presented higher insecticidal activity against S. exigua than the reference compounds tebufenozide, chlorbenzuron and metaflumizone. Among the synthesized compounds, 3b, 3d, 3f, 4b and 4g displayed broad spectrum insecticidal activity.

  14. Supplemental control of lepidopterous pests on Bt transgenic sweet corn with biologically-based spray treatments.

    Science.gov (United States)

    Farrar, Robert R; Shepard, B Merle; Shapiro, Martin; Hassell, Richard L; Schaffer, Mark L; Smith, Chad M

    2009-01-01

    Biologically-based spray treatments, including nucleopolyhedroviruses, neem, and spinosad, were evaluated as supplemental controls for the fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), on transgenic sweet corn, Zea mays (L.) (Poales: Poaceae), expressing a Cry1Ab toxin from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt). Overall, transgenic corn supported lower densities of both pests than did nontransgenic corn. Control of the fall armyworm was improved in both whorl-stage and tassel-stage corn by the use of either a nucleopolyhedrovirus or neem, but the greatest improvement was seen with spinosad. Only spinosad consistently reduced damage to ears, which was caused by both pest species. In general, efficacy of the spray materials did not differ greatly between transgenic and nontransgenic corn.

  15. Caractérisation du savoir paysan sur les insectes nuisibles du pois d'Angole (Cajanus Cajan (L. Millsp. dans le Nord de l'Ouganda

    Directory of Open Access Journals (Sweden)

    Velay F.

    2001-01-01

    Full Text Available Characterization of indigenous traditional knowledge on insect pests of pigeonpea (Cajanus cajan (L. Millsp. in Northern Uganda. In order to assess the perception of the main insect pests of pigeonpea (Cajanus cajan (L. Millsp. by small farmers and to inventoriate methods traditionally used to control these insects, a survey was conducted in 41 households of Northern Uganda (Lira and Apac districts. Virtually all small farmers (95/ considered blister beetle (Mylabris sp., which is the most conspicious insect damaging pigeonpea at the flowering stage, as the main pest of the crop. This is conflicting with field observations made earlier in Northern Uganda which pointed out pod borers (Helicoverpa armigera Huebner and Maruca vitrata Geyer and pod sucking bugs (mainly Clavigralla sp. as the most damaging pests for pigeonpea production. A new pest of pigeonpea, Luprops baldius Mueller, was identified during this survey. Its adults and larvae are damaging to mature pods in case of late harvest.

  16. Enhancement of Bacillus thuringiensis insecticidal activity by combining Cry1Ac and bi-functional toxin HWTX-XI from spider.

    Science.gov (United States)

    Sun, Yunjun; Fu, Zujiao; He, Xiaohong; Yuan, Chunhua; Ding, Xuezhi; Xia, Liqiu

    2016-03-01

    In order to assess the potency of bi-functional HWTX-XI toxin from spider Ornithoctonus huwena in improving the insecticidal activity of Bacillus thuringiensis, a fusion gene of cry1Ac and hwtx-XI was constructed and expressed in an acrystalliferous B. thuringiensis strain Cry(-)B. Western blot analysis and microscopic observation revealed that the recombinant strain could express 140-kDa Cry1Ac-HWTX-XI fusion protein and produce parasporal inclusions during sporulation. Bioassay using the larvae of Helicoverpa armigera and Spodoptera exigua showed that the Cry1Ac-HWTX-XI fusion was more toxic than the control Cry1Ac protoxin, as revealed by 95% lethal concentration. Our study indicated that the HWTX-XI from spider might be a candidate for enhancing the toxicity of B. thuringiensis products.

  17. Spatial and Temporal Distributions of the Fourth Generation Cotton Bollworm Eggs on Summer Corn Seeded at Different Times in North China

    Institute of Scientific and Technical Information of China (English)

    WANG Zhen-ying; HE Kang-lai; WEN Li-ping; ZHANG Guang-yi; ZHENG Li

    2002-01-01

    The spatial and temporal distributions of the cotton bollworm (Helicoverpa armigera Hübner) eggs on summer corn seeded at early-, middle- and late-times were studied in 1998 - 1999 in Hengshui, Hebei Province in North China. There were several egg peaks during the period from the middle to late August, which were coincided with the pollen-shedding or blister stage of summer corn depending on the change of bollworm occurrence. The eggs were mainly deposited on silks of ears, and leaves and sheaths above the ears.The number of eggs laid on middle- and late-seeded summer corn were higher than that on the early-planted one, resulting in more heavy damage the on late-seeded corn.

  18. The natural refuge policy for Bt cotton (Gossypium L. in Pakistan – a situation analysis

    Directory of Open Access Journals (Sweden)

    Muhammad Sajjad Ali

    2013-07-01

    Full Text Available Bt cotton (event Cry1Ac was formally commercialized in Pakistan in 2010. However, there has been an increasing trend of planting unauthorized Bt cotton germplasm in farmers' fields since 2003 with a high rate of adoption in the core cotton areas especially in the province Punjab. The transgenic cotton technology has provided the growers with substantial economic benefits and has reduced their dependence on pesticides for pest control, especially against Helicoverpa armigera (Hubner. However, keeping in view the capacity of this insect to develop resistance against novel chemical formulations, it is easily speculated that Bt toxin, too, is no exception. Refuge crop policy for mono transgenic crop events has helped in delaying the rate of resistance evolution in the target pests. Thus, in Pakistan, where planting of structured refuge crops along Bt cotton fields is not mandatory, the effectiveness and durability of Bt cotton technology may decrease due to a number of factors which are discussed in this review.

  19. Enhancement of Bacillus thuringiensis insecticidal activity by combining Cry1Ac and bi-functional toxin HWTX-XI from spider.

    Science.gov (United States)

    Sun, Yunjun; Fu, Zujiao; He, Xiaohong; Yuan, Chunhua; Ding, Xuezhi; Xia, Liqiu

    2016-03-01

    In order to assess the potency of bi-functional HWTX-XI toxin from spider Ornithoctonus huwena in improving the insecticidal activity of Bacillus thuringiensis, a fusion gene of cry1Ac and hwtx-XI was constructed and expressed in an acrystalliferous B. thuringiensis strain Cry(-)B. Western blot analysis and microscopic observation revealed that the recombinant strain could express 140-kDa Cry1Ac-HWTX-XI fusion protein and produce parasporal inclusions during sporulation. Bioassay using the larvae of Helicoverpa armigera and Spodoptera exigua showed that the Cry1Ac-HWTX-XI fusion was more toxic than the control Cry1Ac protoxin, as revealed by 95% lethal concentration. Our study indicated that the HWTX-XI from spider might be a candidate for enhancing the toxicity of B. thuringiensis products. PMID:25721170

  20. The recent disciplinal progresses of agricultural entomology in China

    Institute of Scientific and Technical Information of China (English)

    Guo Yuyuan; Liang Gemei

    2009-01-01

    In this paper, four recent advances and achievements of China in agricultural insect research, namely, on the genome of silkworm (Bombyx mori Linnaeus), on the geographical differentiation and regional migration of cotton boll-worm (Helicoverpa armigera (Htthner)) , on the standardized monitoring techniques for safety of honey bee (Apis mel-lifera Linnaeus) products, and on the virus transmission property of small brown planthopper (Laodelphax striatellus (Fallén)) as well as the interactions between vector and rice stripe virus (RSV), were reported. All of these resear-ches are very important for controlling agricultural insect pests and the diseases they transmit, accelerating the molecular biological research of silkworm, and promoting the international trade of honey bee products. Most of these achievements mentioned above have got the national, provincial, ministerial or municipal awards on science and technology.

  1. Characterization of a novel chitinase, DkChi, from Dendrolimus kikuchii nucleopolyhedrovirus.

    Science.gov (United States)

    Wang, Qinghua; Qu, Liangjian; Zhang, Zhilin; Wang, Yuzhu; Zhang, Yongan

    2013-12-01

    Dendrolimus kikuchii Matsumura nucleopolyhedrovirus (DkNPV) is a novel nucleopolyhedrovirus strain that has exhibited high potential as biological control agent against D. kikuchii. In this work, a 1755-bp DkChi gene with sequence homology to a chitinase gene was cloned from the genomic DNA of DkNPV using a DNA fragment library. The DkChi gene, encoding 558 residues protein with a predicted mass of 61.6 kDa, was expressed at high levels in Escherichia coli and purified by affinity chromatography. We confirmed that the prepared protein was the DkChi protein by mass spectrometry analysis. Enzyme activity analysis showed that DkChi had both endo- and exo-chitinase activities. Interestingly, the DkChi protein displayed a strong insecticidal activity against Spodoptera exigua, Hyphantria cunea, Helicoverpa armigera and Lymantria dispar. The results suggest that DkChi is a good candidate protein for significantly contributing to pest control.

  2. Recovery of infectious pariacoto virus from cDNA clones and identification of susceptible cell lines.

    Science.gov (United States)

    Johnson, K N; Ball, L A

    2001-12-01

    Pariacoto virus (PaV) is a nodavirus that was recently isolated in Peru from the Southern armyworm, Spodoptera eridania. Virus particles are non enveloped and about 30 nm in diameter and have T=3 icosahedral symmetry. The 3.0-A crystal structure shows that about 35% of the genomic RNA is icosahedrally ordered, with the RNA forming a dodecahedral cage of 25-nucleotide (nt) duplexes that underlie the inner surface of the capsid. The PaV genome comprises two single-stranded, positive-sense RNAs: RNA1 (3,011 nt), which encodes the 108-kDa catalytic subunit of the RNA-dependent RNA polymerase, and RNA2 (1,311 nt), which encodes the 43-kDa capsid protein precursor alpha. In order to apply molecular genetics to the structure and assembly of PaV, we identified susceptible cell lines and developed a reverse genetic system for this virus. Cell lines that were susceptible to infection by PaV included those from Spodoptera exigua, Helicoverpa zea and Aedes albopictus, whereas cells from Drosophila melanogaster and Spodoptera frugiperda were refractory to infection. To recover virus from molecular clones, full-length cDNAs of PaV RNAs 1 and 2 were cotranscribed by T7 RNA polymerase in baby hamster kidney cells that expressed T7 RNA polymerase. Lysates of these cells were infectious both for cultured cells from Helicoverpa zea (corn earworm) and for larvae of Galleria mellonella (greater wax moth). The combination of infectious cDNA clones, cell culture infectivity, and the ability to produce milligram amounts of virus allows the application of DNA-based genetic methods to the study of PaV structure and assembly. PMID:11711613

  3. Influence of Crop Management and Environmental Factors on Wolf Spider Assemblages (Araneae: Lycosidae) in an Australian Cotton Cropping System.

    Science.gov (United States)

    Rendon, Dalila; Whitehouse, Mary E A; Hulugalle, Nilantha R; Taylor, Phillip W

    2015-02-01

    Wolf spiders (Lycosidae) are the most abundant ground-hunting spiders in the Australian cotton (Gossypium hirsutum L.) agroecosystems. These spiders have potential in controlling pest bollworms, Helicoverpa spp. (Lepidoptera: Noctuidae) in minimum-tilled fields. A study was carried out during a wet growing season (2011-2012) in Narrabri, New South Wales, Australia, to determine how different crop rotations and tillage affect wolf spider assemblages in cotton fields. Spider abundance and species richness did not differ significantly between simple plots (no winter crop) and complex plots (cotton-wheat Triticum aestivum L.-vetch Vicia benghalensis L. rotation). However, the wolf spider biodiversity, as expressed by the Shannon-Weaver and Simpson's indices, was significantly higher in complex plots. Higher biodiversity reflected a more even distribution of the most dominant species (Venatrix konei Berland, Hogna crispipes Koch, and Tasmanicosa leuckartii Thorell) and the presence of more rare species in complex plots. T. leuckartii was more abundant in complex plots and appears to be sensitive to farming disturbances, whereas V. konei and H. crispipes were similarly abundant in the two plot types, suggesting higher resilience or recolonizing abilities. The demographic structure of these three species varied through the season, but not between plot types. Environmental variables had a significant effect on spider assemblage, but effects of environment and plot treatment were overshadowed by the seasonal progression of cotton stages. Maintaining a high density and even distribution of wolf spiders that prey on Helicoverpa spp. should be considered as a conservation biological control element when implementing agronomic and pest management strategies.

  4. Investigation and control on diseases and insect pests of‘No. 5 Weiyu’potato under different planting densities%不同种植密度下‘威芋5号’病虫害种类调查及防治

    Institute of Scientific and Technical Information of China (English)

    李杨; 陈祖瑶; 郑元红; 牟东岭

    2014-01-01

    in this investigation 10 types of diseases and insect pests were found, such as Henosepilachna vigintioctomaculata Motschulsky, Polyphagotarsonemus latus Banks, Acyrthosiphon solani (Kaltenbach), Chrysomelidae Latreille, Helicoverpa armigera Hubner, Streptomyces scabies (Thaxter) Waks.et Henvici, PVY, Phytophthora infestans Mont, Erwinia carotovora subsp and Alternaria solani Sorauer. Incidence rates of diseases and pests increased with plant density. To realize the high yield and good quality cultivation of the‘No. 5 Weiyu’potato cultivars, it was very important to identify the diseases and insect pests correctly and to adopt the integrated control technology.%本次调查总共发现马铃薯病、虫害共10种。分别是马铃薯28星瓢虫(Henosepilachna vigintioctomaculata Motschulsky)、茶黄螨(Polyphagotarsonemus latus Banks)、茄无网蚜(Acyrthosiphon solani Kaltenbach)、叶甲(Chrysomelidae Latreil e)、金针虫(Helicoverpa armigera Hubner)、马铃薯疮痂病(Streptomyces scabies (Thaxter) Waks.et Henvici),马铃薯病毒病(PVY)、马铃薯晚疫病(Phytophthora infestans Mont)、马铃薯软腐病(Erwinia carotovora subsp)和马铃薯早疫病(Alternaria solani Sorauer),病虫害的发生率随着种植密度增大而增加。为保证‘威芋5号’的高产、优产,准确识别病虫害的种类,采用综合防治技术是关键。

  5. 频振式杀虫灯在烟草害虫防治中的应用研究%The Application Research of Frequency Trembler Lamp in Control of Tobacco Insect Pest

    Institute of Scientific and Technical Information of China (English)

    孔凡全; 朱列书

    2012-01-01

    为了探索云南烟叶生产中害虫防治的有效方法,在火木龙现代烟草示范区利用频振式杀虫灯开展了烟草主要害虫防治示范试验,结果表明:该杀虫灯把杀虫工作日常化,能有效防止爆发大面积虫害;对蚜茧蜂、食蚜、蝇草蛉等天敌有一定的保护作用,对烟青虫、斜纹夜蛾、金龟子等害虫防效显著;投入成本低,控制面积大,操作简便;通过物理方法诱杀害虫,大大减少农药用量,同时不会使害虫产生抗药性,降低了烟叶农药残留,提高烟叶品质,减少对环境的污染,避免人畜中毒事件发生.这说明频振式杀虫灯具有较好的经济效益、社会效益和生态效益,可在烟草害虫防治中大面积推广使用.%In order to find effective method for controlling insect pests during production of tobacco leaves, a demonstrating experiment for controlling insect pests of tobacco by using frequency trembler lamp were conducted in Huomulong modern tobacco test area. The results showed that this frequency trembler lamp makes the killing insect pests to be routinized, and it can prevent the occurrence of large scale insect pests efficiently. The lamp has certain protection effect for the natural enemy of tobacco insect pests, such as Aphid, Syrphidae and Chrysopidae; meanwhile, it has significant control effect on tobacco insect pests, such as Heliothis assulta Guenee, Prodenia litura and Cheirotonus. The lamp has lots of good characteristics, such as low input and cost, large controlling area, easy use, etc. Using this frequency trembler lamp is a physical way to trapping and killing insect pests, so it will help to reduce pesticide consumption and pesticide residue greatly, and the insects would not have drug resistance, therefore, it can improve tobacco quality, reduce contamination on environment, and avoid poisoning of human and livestock. Therefore, the frequency trembler lamp can be popularized in a large scale for it has good

  6. Do insect outbreaks reduce the severity of subsequent forest fires?

    Science.gov (United States)

    Meigs, Garrett W.; Zald, Harold S. J.; Campbell, John L.; Keeton, William S.; Kennedy, Robert E.

    2016-04-01

    Understanding the causes and consequences of rapid environmental change is an essential scientific frontier, particularly given the threat of climate- and land use-induced changes in disturbance regimes. In western North America, recent widespread insect outbreaks and wildfires have sparked acute concerns about potential insect-fire interactions. Although previous research shows that insect activity typically does not increase wildfire likelihood, key uncertainties remain regarding insect effects on wildfire severity (i.e., ecological impact). Recent assessments indicate that outbreak severity and burn severity are not strongly associated, but these studies have been limited to specific insect or fire events. Here, we present a regional census of large wildfire severity following outbreaks of two prevalent bark beetle and defoliator species, mountain pine beetle (Dendroctonus ponderosae) and western spruce budworm (Choristoneura freemani), across the US Pacific Northwest. We first quantify insect effects on burn severity with spatial modeling at the fire event scale and then evaluate how these effects vary across the full population of insect-fire events (n = 81 spanning 1987-2011). In contrast to common assumptions of positive feedbacks, we find that insects generally reduce the severity of subsequent wildfires. Specific effects vary with insect type and timing, but both insects decrease the abundance of live vegetation susceptible to wildfire at multiple time lags. By dampening subsequent burn severity, native insects could buffer rather than exacerbate fire regime changes expected due to land use and climate change. In light of these findings, we recommend a precautionary approach when designing and implementing forest management policies intended to reduce wildfire hazard and increase resilience to global change.

  7. Snowmelt as a driver of ecosystem response in water limited mountain forests of the Western U.S.

    Science.gov (United States)

    Molotch, N. P.; Trujillo, E.

    2015-12-01

    Recent large-scale changes in snow cover over Western North America associated with climate warming may have widespread impacts on water availability. These changes have potentially varied impacts on water availability as snowmelt influences, soil moisture, streamflow, and evapotranspiration. These changes may significantly alter runoff production and gross primary productivity in mountain forests. Analysis of remotely sensed and in situ soil moisture data indicate strong sensitivities of the timing of peak soil moisture to the timing of snowmelt. Observations of vegetation greenness indicate strong forest and understory growth dependencies associated with snow accumulation, snowmelt, and soil moisture with peak snow water equivalent explaining 40-50% of inter-annual greenness variability in the Rocky Mountains. Examples of these dependencies will be presented based on the 2012 drought in the Southwestern US whereby near record low snow accumulation and record high potential evapotranspiration have resulted in record low forest greening as evident in the 30+ year satellite record. Forest response to aridity in 2012 was exacerbated by forest disturbance with greenness anomalies 90% greater in magnitude in Bark Beetle and Spruce Budworm affected areas versus undisturbed areas and 182% greater in magnitude in areas impacted by fire. Greenness sensitivities to aridity showed seasonal dependencies with record high Normalized Difference Vegetation Index (NDVI) values in April (14% above average) and record low NDVI values in July (7% below average). Gross primary productivity estimates from the Moderate Resolution Imaging Spectroradiometer (MODIS) and from the Niwot Ridge, Colorado Ameriflux tower indicate record high April GPP (30% and 90% above average for MODIS and the tower, respectively) and record low July GPP (19% and 30% below average, respectively). These energy, water, ecosystem relationships indicate that the sensitivity of ecosystems to changes in climate is

  8. Generation of a Transcriptome in a Model Lepidopteran Pest, Heliothis virescens, Using Multiple Sequencing Strategies for Profiling Midgut Gene Expression.

    Directory of Open Access Journals (Sweden)

    Omaththage P Perera

    Full Text Available Heliothine pests such as the tobacco budworm, Heliothis virescens (F., pose a significant threat to production of a variety of crops and ornamental plants and are models for developmental and physiological studies. The efforts to develop new control measures for H. virescens, as well as its use as a relevant biological model, are hampered by a lack of molecular resources. The present work demonstrates the utility of next-generation sequencing technologies for rapid molecular resource generation from this species for which lacks a sequenced genome. In order to amass a de novo transcriptome for this moth, transcript sequences generated from Illumina, Roche 454, and Sanger sequencing platforms were merged into a single de novo transcriptome assembly. This pooling strategy allowed a thorough sampling of transcripts produced under diverse environmental conditions, developmental stages, tissues, and infections with entomopathogens used for biological control, to provide the most complete transcriptome to date for this species. Over 138 million reads from the three platforms were assembled into the final set of 63,648 contigs. Of these, 29,978 had significant BLAST scores indicating orthologous relationships to transcripts of other insect species, with the top-hit species being the monarch butterfly (Danaus plexippus and silkworm (Bombyx mori. Among identified H. virescens orthologs were immune effectors, signal transduction pathways, olfactory receptors, hormone biosynthetic pathways, peptide hormones and their receptors, digestive enzymes, and insecticide resistance enzymes. As an example, we demonstrate the utility of this transcriptomic resource to study gene expression profiling of larval midguts and detect transcripts of putative Bacillus thuringiensis (Bt Cry toxin receptors. The substantial molecular resources described in this study will facilitate development of H. virescens as a relevant biological model for functional genomics and for new

  9. Do insect outbreaks reduce the severity of subsequent forest fires?

    Science.gov (United States)

    Meigs, Garrett W.; Zald, Harold S. J.; Campbell, John L.; Keeton, William S.; Kennedy, Robert E.

    2016-04-01

    Understanding the causes and consequences of rapid environmental change is an essential scientific frontier, particularly given the threat of climate- and land use-induced changes in disturbance regimes. In western North America, recent widespread insect outbreaks and wildfires have sparked acute concerns about potential insect–fire interactions. Although previous research shows that insect activity typically does not increase wildfire likelihood, key uncertainties remain regarding insect effects on wildfire severity (i.e., ecological impact). Recent assessments indicate that outbreak severity and burn severity are not strongly associated, but these studies have been limited to specific insect or fire events. Here, we present a regional census of large wildfire severity following outbreaks of two prevalent bark beetle and defoliator species, mountain pine beetle (Dendroctonus ponderosae) and western spruce budworm (Choristoneura freemani), across the US Pacific Northwest. We first quantify insect effects on burn severity with spatial modeling at the fire event scale and then evaluate how these effects vary across the full population of insect–fire events (n = 81 spanning 1987–2011). In contrast to common assumptions of positive feedbacks, we find that insects generally reduce the severity of subsequent wildfires. Specific effects vary with insect type and timing, but both insects decrease the abundance of live vegetation susceptible to wildfire at multiple time lags. By dampening subsequent burn severity, native insects could buffer rather than exacerbate fire regime changes expected due to land use and climate change. In light of these findings, we recommend a precautionary approach when designing and implementing forest management policies intended to reduce wildfire hazard and increase resilience to global change.

  10. Disruption of insect isoprenoid biosynthesis with pyridinium bisphosphonates.

    Science.gov (United States)

    Sen, Stephanie E; Wood, Lyndsay; Jacob, Reshma; Xhambazi, Alisa; Pease, Britanny; Jones, Alexis; Horsfield, Taylor; Lin, Alice; Cusson, Michel

    2015-08-01

    Farnesyl diphosphate synthase (FPPS) catalyzes the condensation of the non-allylic diphosphate, isopentenyl diphosphate (IPP; C5), with the allylic diphosphate primer dimethylallyl diphosphate (DMAPP; C5) to generate the C15 prenyl chain (FPP) used for protein prenylation as well as sterol and terpene biosynthesis. Here, we designed and prepared a series of pyridinium bisphosphonate (PyrBP) compounds, with the aim of selectively inhibiting FPPS of the lepidopteran insect order. FPPSs of Drosophila melanogaster and the spruce budworm, Choristoneura fumiferana, were inhibited by several PyrBPs, and as hypothesized, larger bisphosphonates were more selective for the lepidopteran protein and completely inactive towards dipteran and vertebrate FPPSs. Cell growth of a D. melanogaster cell line was adversely affected by exposure to PyrPBs that were strongly inhibitory to insect FPPS, although their effect was less pronounced than that observed upon exposure to the electron transport disrupter, chlorfenapyr. To assess the impact of PyrBPs on lepidopteran insect growth and development, we performed feeding and topical studies, using the tobacco hornworm, Manduca sexta, as our insect model. The free acid form of a PyrBP and a known bisphosphonate inhibitor of vertebrate FPPS, alendronate, had little to no effect on larval M. sexta; however, the topical application of more lipophilic ester PyrBPs caused decreased growth, incomplete larval molting, cuticle darkening at the site of application, and for those insects that survived, the formation of larval-pupal hybrids. To gain a better understanding of the structural differences that produce selective lepidopteran FPPS inhibition, homology models of C. fumiferana and D. melanogaster FPPS (CfFPPS2, and DmFPPS) were prepared. Docking of substrates and PyrBPs demonstrates that differences at the -3 and -4 positions relative to the first aspartate rich motif (FARM) are important factors in the ability of the lepidopteran enzyme to

  11. Examining mechanisms in the final stages of the elimination of boreal tree species on vulnerable sites in boreal Alaska

    Science.gov (United States)

    Juday, G. P.; Jess, R.; Alix, C. M.; Verbyla, D.

    2015-12-01

    The boreal forest of Alaska and western Canada exist in a complex mosaic of environments determined by elevation, aspect of exposure, and longitudinal and latitudinal gradients of change from warm, dry continental to maritime-influenced conditions. This forest region is largely made up of trees with two growth responses to temperature increases. Trees that decrease in growth are termed negative responders, and occupy warm, dry sites at low elevations. Trees that increase in radial growth are termed positive responders, and are largely in western Alaska, and at high elevation of the Brooks and Alaska Ranges. Since the Pacific climate regime shift of the 1970s, mature trees at low elevation sites have experienced increasing climate stress in several quasi-decadal cycles of intensifying drought stress. NDVI trends and tree ring records demonstrating radial growth decline are coherent. Phenological monitoring of spruce height growth also indicates that depletion of spring soil moisture is a critical process driven by the interaction of early warm season temperatures and precipitation. Novel biotic disturbance agents including spruce budworm, outbreaks of which are triggered by warm temperature anomalies related to its biology, and aspen leaf miner are depressing realized growth below climatically predicted levels, suggesting a pathway by which tree death is likely to occur before absolute temperature limits. As a result, insect outbreaks are degrading the otherwise strong long-term climate signal in Alaska boreal trees. However, young tree (> 40 yrs.) regeneration generally does not yet display the symptoms of acute high temperature stress. Overall, on these vulnerable sites, if temperature increases similar to the past 40 years continue, long term survival prospects are questionable because the climate conditions would be outside the limits that have historically defined the species ranges of aspen, Alaska birch, and black and white spruce.

  12. A naturally occurring plant cysteine protease possesses remarkable toxicity against insect pests and synergizes Bacillus thuringiensis toxin.

    Directory of Open Access Journals (Sweden)

    Srinidi Mohan

    Full Text Available When caterpillars feed on maize (Zea maize L. lines with native resistance to several Lepidopteran pests, a defensive cysteine protease, Mir1-CP, rapidly accumulates at the wound site. Mir1-CP has been shown to inhibit caterpillar growth in vivo by attacking and permeabilizing the insect's peritrophic matrix (PM, a structure that surrounds the food bolus, assists in digestion and protects the midgut from microbes and toxins. PM permeabilization weakens the caterpillar defenses by facilitating the movement of other insecticidal proteins in the diet to the midgut microvilli and thereby enhancing their toxicity. To directly determine the toxicity of Mir1-CP, the purified recombinant enzyme was directly tested against four economically significant Lepidopteran pests in bioassays. Mir1-CP LC(50 values were 1.8, 3.6, 0.6, and 8.0 ppm for corn earworm, tobacco budworm, fall armyworm and southwestern corn borer, respectively. These values were the same order of magnitude as those determined for the Bacillus thuringiensis toxin Bt-CryIIA. In addition to being directly toxic to the larvae, 60 ppb Mir1-CP synergized sublethal concentrations of Bt-CryIIA in all four species. Permeabilization of the PM by Mir1-CP probably provides ready access to Bt-binding sites on the midgut microvilli and increases its activity. Consequently, Mir1-CP could be used for controlling caterpillar pests in maize using non-transgenic approaches and potentially could be used in other crops either singly or in combination with Bt-toxins.

  13. Baseline susceptibility to Cry1Ac insecticidal protein in Heliothis virescens (Lepidoptera: Noctuidae) populations in Brazil.

    Science.gov (United States)

    Albernaz, K C; Merlin, B L; Martinelli, S; Head, G P; Omoto, C

    2013-08-01

    The tobacco budworm, Heliothis virescens (F.), is one of the target pests of genetically modified cotton expressing Cry1Ac insecticidal protein (Bt cotton) derived from Bacillus thuringiensis Berliner. This study was conducted to evaluate the susceptibility of field-collected populations of H. virescens to Cry1Ac to establish a baseline for use in an insect resistance management program for Bt cotton in Brazil. Insects were sampled from the main Brazilian cotton-growing regions (Bahia, Mato Grosso, Mato Grosso do Sul, and Goiás) during the cropping seasons of 2007/08 and 2008/09. Cry1Ac susceptibility was estimated by using diet incorporation bioassays. H. virescens was highly susceptible to Cry1Ac protein. The estimated LC50 values varied from 0.18 to 0.66 microg of Cry1Ac/ml of diet among the 2007-2008 populations (approximately 3.7-fold variation). Similarly, the EC50 values based on growth inhibition ranged from 0.0053 to 0.0161 microg of Cry1Ac/ml of diet for the 2007-2008 populations (approximately 3.0-fold variation). A joint analysis of the mortality data across all tested populations was used to develop and validate the diagnostic concentrations of 3.1 and 5.6 microg of Cry1Ac/ml of diet, the upper bound of the confidence interval and twice the LC99 were selected, for resistance monitoring programs of H. virescens to Cry1Ac protein in Brazil.

  14. Generation of a Transcriptome in a Model Lepidopteran Pest, Heliothis virescens, Using Multiple Sequencing Strategies for Profiling Midgut Gene Expression

    Science.gov (United States)

    Popham, Holly J. R.; Gould, Fred; Adang, Michael J.; Jurat-Fuentes, Juan Luis

    2015-01-01

    Heliothine pests such as the tobacco budworm, Heliothis virescens (F.), pose a significant threat to production of a variety of crops and ornamental plants and are models for developmental and physiological studies. The efforts to develop new control measures for H. virescens, as well as its use as a relevant biological model, are hampered by a lack of molecular resources. The present work demonstrates the utility of next-generation sequencing technologies for rapid molecular resource generation from this species for which lacks a sequenced genome. In order to amass a de novo transcriptome for this moth, transcript sequences generated from Illumina, Roche 454, and Sanger sequencing platforms were merged into a single de novo transcriptome assembly. This pooling strategy allowed a thorough sampling of transcripts produced under diverse environmental conditions, developmental stages, tissues, and infections with entomopathogens used for biological control, to provide the most complete transcriptome to date for this species. Over 138 million reads from the three platforms were assembled into the final set of 63,648 contigs. Of these, 29,978 had significant BLAST scores indicating orthologous relationships to transcripts of other insect species, with the top-hit species being the monarch butterfly (Danaus plexippus) and silkworm (Bombyx mori). Among identified H. virescens orthologs were immune effectors, signal transduction pathways, olfactory receptors, hormone biosynthetic pathways, peptide hormones and their receptors, digestive enzymes, and insecticide resistance enzymes. As an example, we demonstrate the utility of this transcriptomic resource to study gene expression profiling of larval midguts and detect transcripts of putative Bacillus thuringiensis (Bt) Cry toxin receptors. The substantial molecular resources described in this study will facilitate development of H. virescens as a relevant biological model for functional genomics and for new biological

  15. Generation of a Transcriptome in a Model Lepidopteran Pest, Heliothis virescens, Using Multiple Sequencing Strategies for Profiling Midgut Gene Expression.

    Science.gov (United States)

    Perera, Omaththage P; Shelby, Kent S; Popham, Holly J R; Gould, Fred; Adang, Michael J; Jurat-Fuentes, Juan Luis

    2015-01-01

    Heliothine pests such as the tobacco budworm, Heliothis virescens (F.), pose a significant threat to production of a variety of crops and ornamental plants and are models for developmental and physiological studies. The efforts to develop new control measures for H. virescens, as well as its use as a relevant biological model, are hampered by a lack of molecular resources. The present work demonstrates the utility of next-generation sequencing technologies for rapid molecular resource generation from this species for which lacks a sequenced genome. In order to amass a de novo transcriptome for this moth, transcript sequences generated from Illumina, Roche 454, and Sanger sequencing platforms were merged into a single de novo transcriptome assembly. This pooling strategy allowed a thorough sampling of transcripts produced under diverse environmental conditions, developmental stages, tissues, and infections with entomopathogens used for biological control, to provide the most complete transcriptome to date for this species. Over 138 million reads from the three platforms were assembled into the final set of 63,648 contigs. Of these, 29,978 had significant BLAST scores indicating orthologous relationships to transcripts of other insect species, with the top-hit species being the monarch butterfly (Danaus plexippus) and silkworm (Bombyx mori). Among identified H. virescens orthologs were immune effectors, signal transduction pathways, olfactory receptors, hormone biosynthetic pathways, peptide hormones and their receptors, digestive enzymes, and insecticide resistance enzymes. As an example, we demonstrate the utility of this transcriptomic resource to study gene expression profiling of larval midguts and detect transcripts of putative Bacillus thuringiensis (Bt) Cry toxin receptors. The substantial molecular resources described in this study will facilitate development of H. virescens as a relevant biological model for functional genomics and for new biological

  16. A naturally occurring plant cysteine protease possesses remarkable toxicity against insect pests and synergizes Bacillus thuringiensis toxin.

    Science.gov (United States)

    Mohan, Srinidi; Ma, Peter W K; Williams, W Paul; Luthe, Dawn S

    2008-03-12

    When caterpillars feed on maize (Zea maize L.) lines with native resistance to several Lepidopteran pests, a defensive cysteine protease, Mir1-CP, rapidly accumulates at the wound site. Mir1-CP has been shown to inhibit caterpillar growth in vivo by attacking and permeabilizing the insect's peritrophic matrix (PM), a structure that surrounds the food bolus, assists in digestion and protects the midgut from microbes and toxins. PM permeabilization weakens the caterpillar defenses by facilitating the movement of other insecticidal proteins in the diet to the midgut microvilli and thereby enhancing their toxicity. To directly determine the toxicity of Mir1-CP, the purified recombinant enzyme was directly tested against four economically significant Lepidopteran pests in bioassays. Mir1-CP LC(50) values were 1.8, 3.6, 0.6, and 8.0 ppm for corn earworm, tobacco budworm, fall armyworm and southwestern corn borer, respectively. These values were the same order of magnitude as those determined for the Bacillus thuringiensis toxin Bt-CryIIA. In addition to being directly toxic to the larvae, 60 ppb Mir1-CP synergized sublethal concentrations of Bt-CryIIA in all four species. Permeabilization of the PM by Mir1-CP probably provides ready access to Bt-binding sites on the midgut microvilli and increases its activity. Consequently, Mir1-CP could be used for controlling caterpillar pests in maize using non-transgenic approaches and potentially could be used in other crops either singly or in combination with Bt-toxins.

  17. The future of IPM: whither or wither?

    International Nuclear Information System (INIS)

    The acronym IPM (integrated pest management) has been around for over 50 years and now not only supposedly guides research and extension in pest management but also markets pesticides, is claimed to be undertaken by many growers, and even resonates with public perceptions and politicians. Whether or not IPM programs are sustainable in the longer term under the conflicting stresses and strains of the modern agricultural environment is debatable. We analyse three case studies of IPM development in Australia: citrus IPM in central Queensland, Brassica IPM in southeast Queensland and Helicoverpa management in cotton in eastern Australia. Many management practices for these pests have changed over time. In the more stable citrus system classical biological control along with changed practices (reduced pesticide use) have effectively controlled imported scale insect pests. In Brassicas and cotton, IPM is predominantly of the sample and spray variety where, increasingly, less broad-spectrum insecticides are used and, in cotton, Helicoverpa management includes the deployment of transgenic plants. We question whether or not IPM principles are always consistent with market forces and whether or not the approach is universally applicable for all pest insects when implemented at the small (field or farm) scale. Farmers will adopt cost-effective approaches that minimise their financial risks. For Australia as a whole over the last 30 years insecticide input costs per hectare have increased faster than the price index, reflecting more costly insecticides, changes to the combinations of crops grown and an increase in the overall area of crops cultivated together with possible concomitant changes in pest abundance. Any pest crisis will ensure rapid changes in practice and adoption of technologies, in order to mitigate the short-term financial stresses caused. However, regression to former practices tends to follow (e.g. in Brassica crops). In most cases, we cannot objectively test

  18. Inseticidas para o controle da traça-do-tomateiro e broca-grande e seu impacto sobre Trichogramma pretiosum Insecticides for the control of the South American tomato pinworm and the corn earworm and impact of those products on Trichogramma pretiosum

    Directory of Open Access Journals (Sweden)

    Marina Castelo Branco

    2003-12-01

    Full Text Available Experimentos de campo foram conduzidos entre maio e outubro de 2000 para determinar a eficiência de diversos inseticidas para o controle de Tuta absoluta e Helicoverpa zea e o impacto desses produtos sobre a emergência do parasitóide Trichogramma pretiosum. Os inseticidas testados, bem como as doses em g i.a./ha foram: metoxifenozide (120; 144, clorpirifós (540; 675, tiacloprid (72; 96 e triflumuron (144. O delineamento experimental foi de blocos ao acaso com oito tratamentos (inseticidas e testemunha e cinco repetições, com 40 plantas/parcela. Frutos de tomate foram coletados aos 58, 80 e 87 dias após o transplante das mudas para a determinação da percentagem de frutos danificados pelos insetos. O impacto dos inseticidas sobre T. pretiosum foi avaliado mediante a coleta de 20 ovos de H. zea por parcela aos 61 dias após o transplante, onde foi realizada a avaliação da emergência do parasitóide. Todos os inseticidas reduziram significativamente os danos causados por H. zea. Contudo, nenhum deles foi eficiente para o controle de T. absoluta. Metoxifenozide e clorpirifós (540 não reduziram significativamente o número de ovos parasitados por T. pretiosum quando comparados à testemunha.Field studies were conducted from May to October 2000 to determine the effectiveness of several insecticides in controlling Tuta absoluta and Helicoverpa zea and their impact on emergence of the parasitoid Trichogramma pretiosum. The insecticides tested were: methoxyfenozide (120; 144, clorpirifós (540; 675, tiacloprid (72; 96 and triflumuron (144. Application rates of all insecticides are expressed as g a.i./ha. The experiment was designed as randomized complete block with eight treatments (insecticides and untreated plots with five replications. Tomato fruits were harvested 58; 80 and 87 days after transplanting and the percentage of damaged fruits by both pests determined. The impact of insecticides on T. pretiosum survival was determined

  19. Bats track and exploit changes in insect pest populations.

    Directory of Open Access Journals (Sweden)

    Gary F McCracken

    Full Text Available The role of bats or any generalist predator in suppressing prey populations depends on the predator's ability to track and exploit available prey. Using a qPCR fecal DNA assay, we document significant association between numbers of Brazilian free-tailed bats (Tadarida brasiliensis consuming corn earworm (CEW moths (Helicoverpa zea and seasonal fluctuations in CEW populations. This result is consistent with earlier research linking the bats' diet to patterns of migration, abundance, and crop infestation by important insect pests. Here we confirm opportunistic feeding on one of the world's most destructive insects and support model estimates of the bats' ecosystem services. Regression analysis of CEW consumption versus the moth's abundance at four insect trapping sites further indicates that bats track local abundance of CEW within the regional landscape. Estimates of CEW gene copies in the feces of bats are not associated with seasonal or local patterns of CEW abundance, and results of captive feeding experiments indicate that our qPCR assay does not provide a direct measure of numbers or biomass of prey consumed. Our results support growing evidence for the role of generalist predators, and bats specifically, as agents for biological control and speak to the value of conserving indigenous generalist predators.

  20. Bats track and exploit changes in insect pest populations.

    Science.gov (United States)

    McCracken, Gary F; Westbrook, John K; Brown, Veronica A; Eldridge, Melanie; Federico, Paula; Kunz, Thomas H

    2012-01-01

    The role of bats or any generalist predator in suppressing prey populations depends on the predator's ability to track and exploit available prey. Using a qPCR fecal DNA assay, we document significant association between numbers of Brazilian free-tailed bats (Tadarida brasiliensis) consuming corn earworm (CEW) moths (Helicoverpa zea) and seasonal fluctuations in CEW populations. This result is consistent with earlier research linking the bats' diet to patterns of migration, abundance, and crop infestation by important insect pests. Here we confirm opportunistic feeding on one of the world's most destructive insects and support model estimates of the bats' ecosystem services. Regression analysis of CEW consumption versus the moth's abundance at four insect trapping sites further indicates that bats track local abundance of CEW within the regional landscape. Estimates of CEW gene copies in the feces of bats are not associated with seasonal or local patterns of CEW abundance, and results of captive feeding experiments indicate that our qPCR assay does not provide a direct measure of numbers or biomass of prey consumed. Our results support growing evidence for the role of generalist predators, and bats specifically, as agents for biological control and speak to the value of conserving indigenous generalist predators. PMID:22952782

  1. Improvement of pest resistance in transgenic tobacco plants expressing dsRNA of an insect-associated gene EcR.

    Science.gov (United States)

    Zhu, Jin-Qi; Liu, Shumin; Ma, Yao; Zhang, Jia-Qi; Qi, Hai-Sheng; Wei, Zhao-Jun; Yao, Qiong; Zhang, Wen-Qing; Li, Sheng

    2012-01-01

    The adoption of pest-resistant transgenic plants to reduce yield loss and pesticide utilization has been successful in the past three decades. Recently, transgenic plant expressing double-stranded RNA (dsRNA) targeting pest genes emerges as a promising strategy for improving pest resistance in crops. The steroid hormone, 20-hydroxyecdysone (20E), predominately controls insect molting via its nuclear receptor complex, EcR-USP. Here we report that pest resistance is improved in transgenic tobacco plants expressing dsRNA of EcR from the cotton bollworm, Helicoverpa armigera, a serious lepidopteran pest for a variety of crops. When H. armigera larvae were fed with the whole transgenic tobacco plants expressing EcR dsRNA, resistance to H. armigera was significantly improved in transgenic plants. Meanwhile, when H. armigera larvae were fed with leaves of transgenic tobacco plants expressing EcR dsRNA, its EcR mRNA level was dramatically decreased causing molting defects and larval lethality. In addition, the transgenic tobacco plants expressing H. armigera EcR dsRNA were also resistant to another lepidopteran pest, the beet armyworm, Spodoptera exigua, due to the high similarity in the nucleotide sequences of their EcR genes. This study provides additional evidence that transgenic plant expressing dsRNA targeting insect-associated genes is able to improve pest resistance. PMID:22685585

  2. Evaluation of pest vulnerability of 'Benning' soybean value added and insect resistant near isogenic lines.

    Science.gov (United States)

    Samuel-Foo, Michelle; All, John N; Boerma, H Roger

    2013-04-01

    Crop enhancement with value added traits may affect vulnerability to insects, and evaluating the susceptibility levels of the various value added traits in elite germplasm would aid in developing integrated pest management strategies. During 2007-2008, five 'Benning' soybean (Glycine max (L.) Merr) lines with different value added nutritional traits and four insect resistant quantitative trait loci (QTL) lines were evaluated in an effort to determine their pest vulnerability under artificial and natural insect pest populations. The lines showed variable susceptibility to lepidopterous insect pests classified as defoliators and stem feeders in replicated greenhouse and field tests. The study was carried out in Athens and Midville, GA. The green cloverworm (Hypena scabra (F.)) was the most common lepidopteran defoliator occurring in the fields. Other caterpillar pests found included the soybean looper (Pseudoplusia includens (Walker)), the bollworm (Helicoverpa zea (Boddie)), and the velvetbean caterpillar (Anticarsia gemmatalis (Hübner)). Data indicated that there was no significantly increased pest susceptibility among the value added cultivars with improved nutritional qualities, with the insect resistant quantitative trait loci lines Benning M and Benning MGH consistently being less susceptible to lepidopterous (Noctuidae) leaf injury. PMID:23786071

  3. Improvement of pest resistance in transgenic tobacco plants expressing dsRNA of an insect-associated gene EcR.

    Directory of Open Access Journals (Sweden)

    Jin-Qi Zhu

    Full Text Available The adoption of pest-resistant transgenic plants to reduce yield loss and pesticide utilization has been successful in the past three decades. Recently, transgenic plant expressing double-stranded RNA (dsRNA targeting pest genes emerges as a promising strategy for improving pest resistance in crops. The steroid hormone, 20-hydroxyecdysone (20E, predominately controls insect molting via its nuclear receptor complex, EcR-USP. Here we report that pest resistance is improved in transgenic tobacco plants expressing dsRNA of EcR from the cotton bollworm, Helicoverpa armigera, a serious lepidopteran pest for a variety of crops. When H. armigera larvae were fed with the whole transgenic tobacco plants expressing EcR dsRNA, resistance to H. armigera was significantly improved in transgenic plants. Meanwhile, when H. armigera larvae were fed with leaves of transgenic tobacco plants expressing EcR dsRNA, its EcR mRNA level was dramatically decreased causing molting defects and larval lethality. In addition, the transgenic tobacco plants expressing H. armigera EcR dsRNA were also resistant to another lepidopteran pest, the beet armyworm, Spodoptera exigua, due to the high similarity in the nucleotide sequences of their EcR genes. This study provides additional evidence that transgenic plant expressing dsRNA targeting insect-associated genes is able to improve pest resistance.

  4. Chlorophyll degradation in the gut of generalist and specialist Lepidopteran caterpillars.

    Science.gov (United States)

    Badgaa, Amarsanaa; Jia, Aiqun; Ploss, Kerstin; Boland, Wilhelm

    2014-12-01

    Plant feeding herbivores excrete most of the ingested chlorophyll (Chl) as partly degraded derivatives lacking the phytol side chain and the central magnesium ion. An ecological role of digested and degraded Chls in the interactions between insects, their food plant and other insects has been described recently. To gain more information on common degradation patterns in plant-feeding insects, the orals secretions and frass of five Lepidopteran caterpillars covering generalists and specialists, namely Spodoptera littoralis, Spodoptera eridania, Heliothis virescens, Helicoverpa armigera, Manduca sexta, and, for comparison, of the leaf beetle larva Chrysomela lapponica were analyzed for chlorophyll catabolites. The major degradation products were determined as pheohorbide a/b and pyropheophorbide a/b by using LC-MS, LC-NMR, UV, and fluorescence spectrometry. The compounds were not present in fresh leaves of the food plants (Phaseolus lunatus, Nicotiana tabacum). The catabolite spectrum in generalists and specialists was qualitatively similar and could be attributed to the action of gut proteins and the strongly alkaline milieu in the digestive tract. Due to the anaerobic environment of the larval gut, the tetrapyrrole core of the Chl catabolites was not cleaved. Substantial amounts of Chl a/b metabolites were strongly complexed by a protein in the mid-gut. PMID:25416033

  5. Adenylate kinase 2 (AK2 promotes cell proliferation in insect development

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    Chen Ru-Ping

    2012-09-01

    Full Text Available Abstract Background Adenylate kinase 2 (AK2 is a phosphotransferase that catalyzes the reversible reaction 2ADP(GDP ↔ ATP(GTP + AMP and influences cellular energy homeostasis. However, the role of AK2 in regulating cell proliferation remains unclear because AK2 has been reported to be involved in either cell proliferation or cell apoptosis in different cell types of various organisms. Results This study reports AK2 promotion of cell proliferation using the lepidopteran insect Helicoverpa armigera and its epidermal cell line HaEpi as models. Western blot analysis indicates that AK2 constitutively expresses in various tissues during larval development. Immunocytochemistry analysis indicates that AK2 localizes in the mitochondria. The recombinant expressed AK2 in E. coli promotes cell growth and viability of HaEpi cell line by 3-(4, 5-Dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide (MTT assay. AK2 knockdown in larvae by RNA interference causes larval growth defects, including body weight decrease and development delay. AK2 knockdown in larvae also decreases the number of circulating haemocytes. The mechanism for such effects might be the suppression of gene transcription involved in insect development caused by AK2 knockdown. Conclusion These results show that AK2 regulates cell growth, viability, and proliferation in insect growth and development.

  6. The ORF 113 of Heliocoverpa armigera Single Nucleopolyhedrovirus Encodes a Functional Fibroblast Growth Factor

    Institute of Scientific and Technical Information of China (English)

    Xiang LI; Chang-yong LIANG; Jian-hua SONG; Xin-wen CHEN

    2008-01-01

    Fibroblast growth factor (FGF) is a key regulator of developmental processes. A FGF homolog (vFGF) is found in all lepidopteran baculoviruses. Autographa californica nucleopolyhedrovirus (AcMNPV) and Bombyx mori NPV (BmNPV) vFGFs are chemotactic factors. Here we analyzed the vfgf of Helicoverpa armigera NPV (HearNPV), a group Ⅱ NPV. The HearNPV vfgftranscripts were detected from 18 to 96 h post-infection (hpi) of Hz-AMI cells with HearNPV and encoded a 36 kDa protein, which was secreted into the culture medium. HearNPV vFGF had strong affinity to heparin, a property important for FGF signaling via an FGF receptor. Unlike its AcMNPV homolog, HearNPV vFGF specially chemoattracted Hz-AM 1, but not other insect cells such as Sf9 and Se-UCR and not the mammalian cells 293 and HepG2. HearNPV vFGF is also associated with the envelope of BV but is absent in occlusion-derived virus, which coordinated to the chemotatic activity analysis.

  7. Insecticidal activity of residual Bt protein at the second trophic level

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Measurements were taken of Bt protein expressed in the leaves of transgenic cotton (Gossypium hirsutum) transformed with a synthesized Bt (Bacillus thuringiensis) cry1A gene and its persistent level in larval bodies and faeces of a non-targeted insect pest, beet armyworm (Spodoptera exigua). We performed enzyme linked immunosorbent assays (ELISA) and bioassays using neonate larvae of cotton bollworm (Helicoverpa armigera) to detect the insecticidal activity of residual Bt protein at the second trophic level. The results showed that Bt protein content in functional leaves was different at various developmental stages and was different among plants at the same stage. Even though Bt protein concentration in the larval bodies and faeces decreased 97.5%-99% compared to that found in cotton leaves subsequently fed to beet armyworm larvae, it still had a lethal effect on neonate cotton bollworm larvae. Therefore, Bt protein present at the second trophic level had insecticidal activity. This result is important in understanding and predicting the effect of transgenic plants on nontarget organisms.

  8. Bioefficacy and mode-of-action of some limonoids of salannin group from Azadirachta indica A. Juss and their role in a multicomponent system against lepidopteran larvae

    Indian Academy of Sciences (India)

    Opender Koul; Gurmeet Singh; Rajwinder Singh; Jasbir Singh; W M Daniewski; Stanislaw Berlozecki

    2004-12-01

    Biological activities of the salannin type of limonoids isolated from Azadirachta indica A. Juss were assessed using the gram pod borer Helicoverpa armigera (Hubner) and the tobacco armyworm Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Inhibition of larval growth was concomitant with reduced feeding by neonate and third instar larvae. All three compounds exhibited strong antifeedant activity in a choice leaf disc bioassay with 2.0, 2.3 and 2.8 g/cm2 of 3-O-acetyl salannol, salannol and salannin, respectively deterring feeding by 50% in S. litura larvae. In nutritional assays, all three compounds reduced growth and consumption when fed to larvae without any effect on efficiency of conversion of ingested food (ECI), suggesting antifeedant activity alone. No toxicity was observed nor was there any significant affect on nutritional indices following topical application, further suggesting specific action as feeding deterrents. When relative growth rates were plotted against relative consumption rates, growth efficiency of the H. armigera fed diet containing 3-O-acetyl salannol, salannol or salannin did not differ from that of starved control larvae (used as calibration curve), further confirming the specific antifeedant action of salannin type of limonoids. Where the three compounds were co-administered, no enhancement in activity was observed. Non-azadirachtin limonoids having structural similarities and explicitly similar modes of action, like feeding deterrence in the present case, have no potentiating effect in any combination.

  9. Can other host species of cotton bollworm be non-Bt refuges to prolong the effectiveness of Bt-cotton?

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The potential ecological risks of Bacillus thurigiensis (Bt) insecticides and Bt-crops have caused increasing concern since their commercial release in the field,among which pests' resistance to Bt-crops is the major ecological risk. Refuge tactic, which can produce sensitive populations, has proved to be a key and sound resistance management strategy in USA and Australia; however, no tactics have been performed in China where Bt-cotton is mostly planted with other host crops of cotton bollworm.Genetic variation and gene flow among different host populations of the cotton bollworm Helicoverpa armigera were analyzed using PCR fingerprinting method. The results show that maize and castor-oil plant, as well as cotton can take effect as refuges to prevent resistance of cotton bollworm to Bt-cotton, while peanut and sesame are not as suitable for planting with Bt-cotton as refuges in the field as low gene flow was detected among populations on peanut, sesame and Bt cotton.

  10. The Research of Bt and OC Gene Cotransformation in Tobacco Chloroplast

    Institute of Scientific and Technical Information of China (English)

    SU Ning; YANG Bo; MENG Kun; LI Yi-nü; SUN Meng; SUN Bing-yao; SHEN Gui-fang

    2002-01-01

    The Bt Cry IA (C) chloroplast expression cassette and OC chloroplast expression cassette were constructed. The Bt expression cassette contained the 3.5 kb wild type Bt Cry IA (C) gene under the control of the strong light-induced psbA promoter and terminator from rice (Oryza sativa. L) chloroplast, the gene:trnH-psbA-trnk from tobacco (Nicotiana tabacum. L) as the homologous fragment. The OC chloroplast expression cassette contained the OC gene under the control of 16S promoter and terminator from tobacco, the tobacco gene: psbA-ORF512 as homologous fragment. The two cassettes both had the aadA gene expression cassette as the selectable marker. Leaves of tobacco were cotransformed with the particle bombardment method. After selection by spectinomycin, the transformants were obtained. The integration of Bt and OC gene were confirmed by Southern-blotting analysis, and Western-blotting analysis. Proteinase inhibitor assays showed that the Bt and OC gene had expressed. Bioassays showed that the transgenic tobacco had a significant resistance to the larvae of cotton bollworm ( helicoverpa zea ).

  11. 出口豆类蔬菜害虫种类及危害初步研究%Primarily Study on Sorts and Damage of Pests on Exported Legumious Vegetable

    Institute of Scientific and Technical Information of China (English)

    孙丽娟; 郑长英; 孙立宁; 衣维贤

    2010-01-01

    于2007年6月10日至9月6日对菜用大豆、四季豆、豇豆、扁豆和豌豆等5种出口豆类蔬菜上发生的害虫种类及危害进行了研究.结果表明:发生在上述豆类蔬菜上害虫分属6目18科,共30种.其中危害严重的种类是豌豆上的豌豆潜叶蝇(Chomatomyia horticola Goureau)和棉铃虫(Helicoverpa armigra Hubuer),豇豆和四季豆上的南美斑潜蝇(Liriomyza huidobrensis Blanchard)和美洲斑潜蝇(Liriomyza sativae Blanchard),四季豆上的花生蚜(Aphis craccivora Koch),菜用大豆上的短额负蝗(Atractomorpha sinensis Bolivar)和温室白粉虱(Trialeurodes vaporariorum Westwood),四季豆和豇豆上的朱砂叶螨(Tetranythus cinnabarinus)等.

  12. Cyclic di-GMP contributes to adaption and virulence of Bacillus thuringiensis through a riboswitch-regulated collagen adhesion protein.

    Science.gov (United States)

    Tang, Qing; Yin, Kang; Qian, Hongliang; Zhao, Youwen; Wang, Wen; Chou, Shan-Ho; Fu, Yang; He, Jin

    2016-01-01

    Cyclic di-GMP is a ubiquitous second messenger that regulates diverse cellular processes in bacteria by binding to various protein or riboswitch effectors. In Bacillus thuringiensis BMB171, a c-di-GMP riboswitch termed Bc2 RNA resides in the 5'-untranslated region (5'-UTR) of an mRNA that encodes a collagen adhesion protein (Cap). The expression of cap was strongly repressed in parent strain BMB171 because of the presence of Bc2 RNA but was significantly promoted in the Bc2 RNA markerless deletion mutant. Bc2 RNA acts as a genetic "on" switch, which forms an anti-terminator structure to promote cap read-through transcription upon c-di-GMP binding. As a result, cap transcription was de-repressed under high c-di-GMP levels. Therefore, Bc2 RNA regulates cap expression using a repression/de-repression model. Bc2 RNA-regulated Cap was also found to be tightly associated with motility, aggregation, exopolysaccharide secretion, biofilm formation, and virulence of B. thuringiensis BMB171 against its host insect Helicoverpa armigera. PMID:27381437

  13. Insect damages on structural, morphologic and composition of Bt maize hybrids to silage

    Directory of Open Access Journals (Sweden)

    Geraldo Balieiro Neto

    2013-03-01

    Full Text Available It was aimed to evaluate the effect of insect damage on the morphologic and structural characteristics and chemical composition from maize hybrids DKB 390 and AG 8088 with the Cry1Ab trait versus its nonbiotech counterpart. The GMO did not receive insecticide application and the conventional hybrids received one deltametrina (2.8% application at 42 days. The damages caused bySpodoptera frugiperda and Helicoverpa zea in hybrids with Cry1Ab were smaller than its nonbiotech counterpart. After harvest, 95 days after seedling plants were separated in stalks, ears, leafs, dead leafs and floral pennant. The experimental design was randomized block in factorial arrangement 2 x 2. The height of plant and height of ear, percentage and amount of dead leafs from hybrids with the Cry1Ab were higher than its nonbiotech counterpart. There was higher nutrients transfer from stalks to grain filling and smaller rate stalks:ear on transgenic plant. The quality of the transgenic plants can be better when harvest earlier, by increasing no fiber carbohydrates, but when harvest latter, by increasing stalk percentage and stalk lignin content.

  14. Isolation, structure modeling and function characterization of a trypsin inhibitor from Cassia obtusifolia.

    Science.gov (United States)

    Liu, Zubi; Zhu, Qiankun; Li, Juanjuan; Zhang, Gan; Jiamahate, Aerguli; Zhou, Jiayu; Liao, Hai

    2015-04-01

    A trypsin inhibitor gene (CoTI1) from Cassia obtusifolia was isolated and the deduced amino acid sequence was attributed to the Kunitz-type trypsin inhibitor. The recombined CoTI1, expressed in E. coli, exhibited strong inhibitory effect on bovine trypsin and trypsin-like proteases from Helicoverpa armigera, Spodoptera exigua, and Spodoptera litura. CoTI1 thus presents insecticidal properties that may be useful for the genetic engineering of plants. Leu84, Arg86 and Thr88 were predicted as three key residues by molecular modeling in which Arg86, inserted into the substrate pocket of trypsin, interacted directly with residue Asp189 of trypsin causing the specific inhibition against trypsin. The predicted results were confirmed by site-directed mutagenesis with L84A, R86A and T88A, respectively. The substantial changing expression level of CoTI1 under salt, drought and abscisic acid treatment suggested that CoTI1 might play important role in the resistance against abiotic stress.

  15. Rapid detection of vip1-type genes from Bacillus cereus and characterization of a novel vip binary toxin gene.

    Science.gov (United States)

    Yu, Xiumei; Liu, Tao; Liang, Xiaoxing; Tang, Changqing; Zhu, Jun; Wang, Shiquan; Li, Shuangcheng; Deng, Qiming; Wang, Linxia; Zheng, Aiping; Li, Ping

    2011-12-01

    A PCR-restriction fragment length polymorphism (PCR-RFLP) method for identifying vegetative insecticidal protein (vip) 1-type genes from Bacillus cereus was developed by designing specific primers based on the conserved regions of the genes to amplify vip1-type gene fragments. PCR products were digested with endonuclease AciI, and four known vip1-type genes were identified. Vip1Ac and vip1Aa-type genes appeared in 17 of 26 B. cereus strains. A novel vip1-type gene, vip1Ac1, was identified from B. cereus strain HL12. The vip1Ac1 and vip2Ae3 genes were co-expressed in Escherichia coli strain BL21 by vector pCOLADuet-1. The binary toxin showed activity only against Aphis gossypii (Homoptera), but not for Coleptera (Tenebrio molitor, Holotrichia oblita), Lepidoptera (Spodoptera exigua, Helicoverpa armigera, and Chilo suppressalis), Diptera (Culex quinquefasciatus). The LC(50) of this binary toxin for A. gossypii is 87.5 (34.2-145.3) ng mL(-1) . This is probably only the second report that Vip1 and Vip2 binary toxin shows toxicity against homopteran pests. The PCR-RFLP method developed could be very useful for identifying novel Vip1-Vip2-type binary toxins, and the novel binary toxins, Vip1Ac1 and Vip2Ae3, identified in this study may have applications in biological control of insects, thus avoiding potential problems of resistance.

  16. The influence of a 21 kDa Kunitz-type trypsin inhibitor from nonhost madras thorn, Pithecellobium dulce, seeds on H. armigera (Hübner) (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Pandey, Prabhash K; Singh, Dushyant; Jamal, Farrukh

    2015-05-01

    A trypsin inhibitor purified from the seeds of the Manila tamarind, Pithecellobium dulce (PDTI), was studied for its effects on growth parameters and developmental stages of Helicoverpa armigera. PDTI exhibited inhibitory activity against bovine trypsin (∼86%; ∼1.33 ug/ml IC50). The inhibitory activity of PDTI was unaltered over a wide range of temperature, pH, and in the presence of dithiothreitol. Larval midgut proteases were unable to digest PDTI for up to 12 h of incubation. Dixon and Lineweaver-Burk double reciprocal plots analysis revealed a competitive inhibition mechanism and a Ki of ∼3.9 × 10(-8) M. Lethal dose (0.50% w/w) and dosage for weight reduction by 50% (0.25% w/w) were determined. PDTI showed a dose-dependent effect on mean larval weight and a series of nutritional disturbances. In artificial diet at 0.25% w/w PDTI, the efficiency of conversion of ingested food, of digested food, relative growth rate, and growth index declined, whereas approximate digestibility, relative consumption rate, metabolic cost, consumption index, and total developmental period were increased in larvae. This is the first report of antifeedant and antimetabolic activities of PDTI on midgut proteases of H. armigera.

  17. [Evaluation of reference genes for quantitative real-time PCR normalization in cotton bollworm, Helicoverna armigera].

    Science.gov (United States)

    Chandra, G Sharath; Asokan, R; Manamohan, M; Kumar, N K K; Sita, T

    2014-01-01

    Reverse-transcription quantitative real-time PCR (RT-qPCR), a sensitive technique is being extensively employed in quantification of gene expression. However this requires normalization with suitable reference gene (RG) which is crucial in minimizing inter sample variations. Information regarding suitable RG is scarce in general and more so in insects, including the cotton bollworm, Helicoverpa armigera, an economically important pest. In management of this pest RNA interference (RNAi), is perceived as a potential tool, which is achieved by double-stranded RNA (dsRNA) delivery. These studies demand accurate quantification of gene silencing. In this study we assessed the suitability of five RGs viz. β-actin (ACTB), 18S rRNA (18S), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β-tubulin (TUB) and elongation fator-1-alfa (EF1-α) for gene expression studies in dsRNA treatment and across different developmental stages of H. armigera and ranked using geNorm, NormFinder and BestKeeper software programs. Data analysis revealed that best ranked RGs were varied in dsRNA treatment and in developmental stages. Under dsRNA treatment, 18S and GAPDH were more stable whereas, TUB and GAPDH were more stable across developmental stages. We also demonstrate that inappropriate selection of RG led to erroneous estimation of the target gene, chymotrypsin, expression. These results facilitate accurate quantification of gene expression in H. armigera.

  18. Allelopathic effects of essential oil from Eucalyptus grandis × E.urophylla on pathogenic fungi and pest insects

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This study on the allelopathic effects and chemical components of the essential oil from Eucalyptus grandis × E.urophylla shows that the leaf oil emulsion of E.grandis × E.urophylla can inhibit the proliferation of pathogenic fungi Fusarium oxysporum,Pyriculerie grisea,Glorosprium musa rum and Phytophthora capsici.Pupation and feeding of the pest insects Spodopteralitura Fabricius and Helicoverpa armigera Hubner are shown to be affected with restraining effects which increase with the increasing levels of oil concentration.A GC/MS analysis of the leaf oil indicated that the main components,with a relative content of≥3%,were alloocimene (43.22%),α-pinene (13.63%),γ-terpinene (5.49%),(E)-3,7-dimethyl-2,6-octadien-1-ol (3.58%),β-fenchyl alcohol (4.58%),and 2-amino-3,5-dicyano-6-(4-methoxyphenoxy)-pyridine (3.67%).Terpenes played an important role in the inhibitory effects of E.grandis × E.urophylla essential oil on pathogenic fungi and pest insects.Poor biodiversity of eucalyptus plantations is a function of allelopathy.

  19. Enhanced methanol production in plants provides broad spectrum insect resistance.

    Directory of Open Access Journals (Sweden)

    Sameer Dixit

    Full Text Available Plants naturally emit methanol as volatile organic compound. Methanol is toxic to insect pests; but the quantity produced by most of the plants is not enough to protect them against invading insect pests. In the present study, we demonstrated that the over-expression of pectin methylesterase, derived from Arabidopsis thaliana and Aspergillus niger, in transgenic tobacco plants enhances methanol production and resistance to polyphagous insect pests. Methanol content in the leaves of transgenic plants was measured using proton nuclear spectroscopy (1H NMR and spectra showed up to 16 fold higher methanol as compared to control wild type (WT plants. A maximum of 100 and 85% mortality in chewing insects Helicoverpa armigera and Spodoptera litura larvae was observed, respectively when fed on transgenic plants leaves. The surviving larvae showed less feeding, severe growth retardation and could not develop into pupae. In-planta bioassay on transgenic lines showed up to 99 and 75% reduction in the population multiplication of plant sap sucking pests Myzus persicae (aphid and Bemisia tabaci (whitefly, respectively. Most of the phenotypic characters of transgenic plants were similar to WT plants. Confocal microscopy showed no deformities in cellular integrity, structure and density of stomata and trichomes of transgenic plants compared to WT. Pollen germination and tube formation was also not affected in transgenic plants. Cell wall enzyme transcript levels were comparable with WT. This study demonstrated for the first time that methanol emission can be utilized for imparting broad range insect resistance in plants.

  20. Defensive Sesquiterpenoids from Leaves of Eupatorium adenophorum

    Institute of Scientific and Technical Information of China (English)

    石伟; 骆世洪; 黎胜红

    2012-01-01

    The invasive plant Eupatorium adenophorum Spreng has caused great economic loss in China, and is gravely threatening the native biodiversity and ecosystem. The plant has been phytochemically investigated for the defen- sive chemical substances in its leaves. Three active sesquiterpenoids were isolated and identified, which include a new sesquiterpenoid (1), and two known sesquiterpenoids (2, 3). Their structures were established by spectroscopic studies such as 1D- and 2D-NMR and MS analyses. Meanwhile, the antifeedant activities of these compounds against two generalist plant-feeding insects, Helicoverpa armigera and Spodoptera exigua, were carried out. Com- pound 1 showed significant antifeedant activity against S. exigua with ECs0 = 7.46 μg/cm^2, while compounds 2 and 3 were more active against H. armigera (EC50=2.57 and 3.04 μg/cm^2 respectively). These findings suggest a de- fensive role of sesquiterpenoids in E. adenophorum against herbivores.

  1. Large-scale test of the natural refuge strategy for delaying insect resistance to transgenic Bt crops.

    Science.gov (United States)

    Jin, Lin; Zhang, Haonan; Lu, Yanhui; Yang, Yihua; Wu, Kongming; Tabashnik, Bruce E; Wu, Yidong

    2015-02-01

    The 'natural refuge strategy" for delaying insect resistance to transgenic cotton that produces insecticidal proteins from Bacillus thuringiensis (Bt) relies on refuges of host plants other than cotton that do not make Bt toxins. We tested this widely adopted strategy by comparing predictions from modeling with data from a four-year field study of cotton bollworm (Helicoverpa armigera) resistance to transgenic cotton producing Bt toxin Cry1Ac in six provinces of northern China. Bioassay data revealed that the percentage of resistant insects increased from 0.93% in 2010 to 5.5% in 2013. Modeling predicted that the percentage of resistant insects would exceed 98% in 2013 without natural refuges, but would increase to only 1.1% if natural refuges were as effective as non-Bt cotton refuges. Therefore, the results imply that natural refuges delayed resistance, but were not as effective as an equivalent area of non-Bt cotton refuges. The percentage of resistant insects with nonrecessive inheritance of resistance increased from 37% in 2010 to 84% in 2013. Switching to Bt cotton producing two or more toxins and integrating other control tactics could slow further increases in resistance.

  2. Non-Target Impacts of an Attract-and-Kill Formulation Based on Plant Volatiles: Responses of some Generalist Predators.

    Science.gov (United States)

    Gregg, Peter C; Del Socorro, Alice P; Binns, Matthew R

    2016-07-01

    Responses of non-target insects to a blend of plant volatiles used as components in an attract-and-kill formulation for Helicoverpa spp. (Lepidoptera: Noctuidae) were studied in an Australian cotton field. Two experiments, one involving suction sampling during the day and the other at night, were conducted. Rows that had been treated with the volatile blend, with no added insecticide, were sampled with a large suction sampler 18, 42, and 85 h (day experiment) and 6, 30, and 78 h (night experiment) after treatment. Rows located 5, 10, 20, and 300 m away from the treated row were similarly sampled. Of seven generalist predators, only one accumulated on the treated rows compared to the untreated rows. Of the other six, five were found in lower numbers on the treated rows, and for one no significant effects were detected. Compared to pre-spray baseline levels, numbers of several taxa increased across the whole field after spraying, suggesting area-wide attraction, but localized responses to the treated rows were weak, and apparent repellence was more common than attraction. We suggest that attract-and-kill with plant volatiles should have minimal effects on populations of these predators, and is likely to be compatible with integrated pest management.

  3. An improved PCR-restriction fragment length polymorphism (RFLP) method for the identification of cry1-type genes.

    Science.gov (United States)

    Shu, Changlong; Liu, Dongming; Zhou, Zishan; Cai, Jilin; Peng, Qi; Gao, Jiguo; Song, Fuping; Zhang, Jie

    2013-11-01

    The cry1-type genes of Bacillus thuringiensis represent the largest cry gene family, which contains 50 distinct holotypes. It is becoming more and more difficult to identify cry1-type genes using current methods because of the increasing number of cry1-type genes. In the present study, an improved PCR-restriction fragment length polymorphism (PCR-RFLP) method which can distinguish 41 holotypes of cry1-type genes was developed. This improved method was used to identify cry1-type genes in 20 B. thuringiensis strains that are toxic to lepidoptera. The results showed that the improved method can efficiently identify single and clustered cry1-type genes and can be used to evaluate cry1-type genes in novel strain collections of B. thuringiensis. Among the detected cry1-type genes, we identified four novel genes, cry1Ai, cry1Bb, cry1Ja, and cry1La. The bioassay results from the expressed products of the four novel cry genes showed that Cry1Ai2, Cry1Bb2, and Cry1Ja2 were highly toxic against Plutella xylostella, whereas Cry1La2 exhibited no activity. Moreover, Cry1Ai2 had good lethal activity against Ostrinia furnacalis, Hyphantria cunea, Chilo suppressalis, and Bombyx mori larvae and considerable weight loss activity against Helicoverpa armigera.

  4. Bt resistance in Australian insect pest species.

    Science.gov (United States)

    Downes, Sharon; Walsh, Tom; Tay, Wee Tek

    2016-06-01

    Bt cotton was initially deployed in Australia in the mid-1990s to control the polyphagous pest Helicoverpa armigera (Hübner) which was intractably resistant to synthetic chemistries. A conservative strategy was enforced and resistance to first generation single toxin technology was managed. A decade later, shortly after the release of dual toxin cotton, high baseline frequencies of alleles conferring resistance to one of its components prompted a reassessment of the thinking behind the potential risks to this technology. Several reviews detail the characteristics of this resistance and the nuances of deploying first and second generation Bt cotton in Australia. Here we explore recent advances and future possibilities to estimate Bt resistance in Australian pest species and define what we see as the critical data for enabling effective pre-emptive strategies. We also foreshadow the imminent deployment of three toxin (Cry1Ac, Cry2Ab, Vip3A) Bollgard 3 cotton, and examine aspects of resistance to its novel component, Vip3A, that we believe may impact on its stewardship. PMID:27436735

  5. Corn earworm (Lepidoptera: Noctuidae) in northeastern field corn: infestation levels and the value of transgenic hybrids.

    Science.gov (United States)

    Bohnenblust, Eric; Breining, Jim; Fleischer, Shelby; Roth, Gregory; Tooker, John

    2013-06-01

    Corn earworm, Helicoverpa zea (Boddie), is a polyphagous noctuid pest of agricultural crops across the United States that is gaining attention as a pest of field corn. Before the introduction of transgenic insect-resistant hybrids, this pest was largely ignored in field corn, but now many Bacillus thuringiensis (Bt) corn hybrids have activity against corn earworm. However, the value of control in the northeastern United States is unclear because the risk posed by corn earworm to field corn has not been well characterized. To understand the threat from corn earworm and the value of Bt hybrids in field corn, we assessed corn earworm injury in Bt and non-Bt hybrids at 16 sites across four maturity zones throughout Pennsylvania in 2010, and 10 sites in 2011. We also used corn earworm captures from the PestWatch pheromone trapping network to relate moth activity to larval damage in field corn. Corn earworm damage was less than one kernel per ear at 21 of 26 sites over both years, and the percentage of ears damaged was generally corn earworm damage relative to non-Bt hybrids, but we found no differences among Bt traits. Cumulative moth captures through July effectively predicted damage at the end of the season. Currently, the additional benefit of corn earworm control provided by Bt hybrids is typically less than US$4.00/ha in northeastern field corn.

  6. Impact of corn earworm injury on yield of transgenic corn producing Bt toxins in the Carolinas.

    Science.gov (United States)

    Reay-Jones, Francis P F; Reisig, Dominic D

    2014-06-01

    Transgenic corn, Zea mays L., hybrids expressing insecticidal Cry proteins from Bacillus thuringiensis (Bt) and insecticide applications to suppress injury from Helicoverpa zea (Boddie) were evaluated in Florence, SC, and in Plymouth, NC, in 2012 and 2013. Based on kernel area injured, insecticide applications (chlorantraniliprole) every 3-4 d from R1 until H. zea had cycled out of corn reduced injury by 80-93% in Florence and 94-95% in Plymouth. Despite intensive applications of insecticide (13-18 per trial), limited injury still occurred in all treated plots in 2012, except in DKC 68-03 (Genuity VT Double PRO), based on kernels injured (both locations) and proportion of injured ears (Florence only). In 2013, ear injury was low in Plymouth, with no kernel injury in any insecticide-treated plots, except P1498R (non-Bt) and P1498YHR (Optimum Intrasect). Injury in Florence in 2013 did not occur in treated plots of DKC 68-04 (non-Bt), DKC 68-03 (Genuity VT Double PRO), and N785-3111 (Agrisure Viptera). Yields were not significantly affected by insecticide treatment and were not statistically different among near-isolines with and without Bt traits. Yields were not significantly associated with kernel injury based on regression analyses. The value of using Bt corn hybrids to manage H. zea is discussed.

  7. Induction of a gloverin-like antimicrobial polypeptide in the sugarcane borer Diatraea saccharalis challenged by septic injury

    Directory of Open Access Journals (Sweden)

    J.L.C. Silva

    2010-05-01

    Full Text Available Diatraea saccharalis (Fabricius, 1794 (Lepidoptera: Crambidae is an important pest for Brazilian sugarcane. In the present study, we detected two distinct spots in hemolymph from septic injured larvae (HDs1 and HDs2, which are separated by 2DE gel electrophoresis. Both spots were subjected to in-gel tryptic digestion and MALDI-TOF/TOF analysis, which revealed the sequence VFGTLGSDDSGLFGK present in both HDs1 and HDs2. This sequence had homology and 80% identity with specific Lepidoptera antimicrobial peptides called gloverins. Analyses using the ImageMaster 2D software showed pI 8.94 of the HDs1 spot, which is similar to that described to Hyalophora gloveri gloverin (pI 8.5. Moreover, the 14-kDa molecular mass of the spot HDs1 is compatible to that of gloverins isolated from the hemolymph of Trichoplusia ni, Helicoverpa armigera and H. gloveri. Antimicrobial assays with partially purified fractions containing the HDs1 and HDs2 polypeptides demonstrated activity against Escherichia coli. This is the first report of antimicrobial polypeptides in D. saccharalis, and the identification of these peptides may help in the generation of new strategies to control this pest.

  8. Biorational agents--mechanism and importance in IPM and IRM programs for controlling agricultural pests.

    Science.gov (United States)

    Ishaaya, I; Kontsedalov, S; Mazirov, D; Horowitz, A R

    2001-01-01

    Among the new approaches for controlling agricultural pests is the development of novel compounds affecting specific processes in insects such as chitin synthesis inhibitors, juvenile hormone mimics and ecdysone agonists. In addition, efforts have been made to develop compounds acting selectively on groups of insects by inhibiting or enhancing biochemical sites such as respiration (diafenthiuron), the nicotinyl acetylcholine receptors (imidacloprid and acetamiprid), the GABA receptors (avermectins), the salivary glands of sucking pests (pymetrozine) and others. Among the most recent novel insecticides with selective properties are novaluron, thiamethoxam, emamectin and spinosad. Novaluron (Rimon) is a novel chitin synthesis inhibitor that acts by both ingestion and contact. It is a powerful suppressor of lepidopteran larvae such as Spodoptera littoralis and Helicoverpa armigera (by ingestion) and of whiteflies such as Bemisia tabaci and Trialeurodes vaporariorum (by contact). Thiamethoxam (Actarn), a novel neonicotinoid acts specifically on aphids and whiteflies. Emamectin (Proclaim), an avermectin derivative acts on GABA receptor affecting diversity of insects such as mites, lepidopterans and thrips. Spinosad (Tracer) seems to act on both acetylcholine and GABA receptors affecting diversity of insect species and is considered an important agent for controlling the western flower thrips.

  9. Expansion of a bitter taste receptor family in a polyphagous insect herbivore.

    Science.gov (United States)

    Xu, Wei; Papanicolaou, Alexie; Zhang, Hui-Jie; Anderson, Alisha

    2016-01-01

    The Insect taste system plays a central role in feeding behaviours and co-evolution of insect-host interactions. Gustatory receptors form the interface between the insect taste system and the environment. From genome and transcriptome sequencing we identified 197 novel gustatory receptor (GR) genes from the polyphagous pest Helicoverpa armigera. These GRs include a significantly expanded bitter receptor family (180 GRs) that could be further divided into three categories based on polypeptide lengths, gene structure and amino acid sequence. Type 1 includes 29 bitter Gr genes that possess introns. Type 2 includes 13 long intronless bitter Gr genes, while Type 3 comprises 131 short intronless bitter Gr genes. Calcium imaging analysis demonstrated that three Type 3 GRs (HarmGR35, HarmGR50 and HarmGR195) can be activated by a crude extract of cotton leaves. HarmGR195, a GR specifically and selectively expressed in adult tarsi, showed a specific response to proline, an amino acid widely present in plant tissues. We hypothesise that the expansion in the H. armigera GR family may be functionally tied to its polyphagous behavior. Understanding the molecular basis of polyphagy may provide opportunities for the development of new environmentally friendly pest control strategies. PMID:27032373

  10. Transgenic tobacco plants expressing synthetic Cry1Ac and Cry1le genes are more toxic to cotton bollworm than those containing one gene

    Institute of Scientific and Technical Information of China (English)

    LIAN Yun; JIA ZhiWei; HE KangLai; LIU YunJun; SONG FuPing; WANG BaoMin; WANG GuoYing

    2008-01-01

    Transgenic tobacco plants carrying Cry1Ac, Crylle or both genes were obtained. In the leaves of transgenic plants carrying both genes, the contents of CrylAc and Cry1le proteins were 0.173% and 0.131% of the total proteins, respectively, Cry1Ac protein content was 0.182 % and Cry1le protein con-tent was 0.124% of the total proteins in the leaves of transgenic plants containing only one Bt gone. Fresh leaves of transgenic tobacco and wild-type plants were used for the insect bioassay against wild-type and Cry1Ac-resistant cotton bollworm (Helicoverpa armigera). The bioassay results showed that transgenic plants carrying both genes were significantly more toxic to wild-type and Cry1Ac-resistant cotton bollworm than those carrying Cry1Ac or Cry1le alone. This study indicates that the higher toxicity of transgenic tobacco plants carrying both genes is caused by the cooperative function of both Bt proteins, thus providing a potential way to delay the development of insect resis-tance to transgenic crops.

  11. Molecular basis of the remarkable species selectivity of an insecticidal sodium channel toxin from the African spider Augacephalus ezendami

    Science.gov (United States)

    Herzig, Volker; Ikonomopoulou, Maria; Smith, Jennifer J.; Dziemborowicz, Sławomir; Gilchrist, John; Kuhn-Nentwig, Lucia; Rezende, Fernanda Oliveira; Moreira, Luciano Andrade; Nicholson, Graham M.; Bosmans, Frank; King, Glenn F.

    2016-01-01

    The inexorable decline in the armament of registered chemical insecticides has stimulated research into environmentally-friendly alternatives. Insecticidal spider-venom peptides are promising candidates for bioinsecticide development but it is challenging to find peptides that are specific for targeted pests. In the present study, we isolated an insecticidal peptide (Ae1a) from venom of the African spider Augacephalus ezendami (family Theraphosidae). Injection of Ae1a into sheep blowflies (Lucilia cuprina) induced rapid but reversible paralysis. In striking contrast, Ae1a was lethal to closely related fruit flies (Drosophila melanogaster) but induced no adverse effects in the recalcitrant lepidopteran pest Helicoverpa armigera. Electrophysiological experiments revealed that Ae1a potently inhibits the voltage-gated sodium channel BgNaV1 from the German cockroach Blattella germanica by shifting the threshold for channel activation to more depolarized potentials. In contrast, Ae1a failed to significantly affect sodium currents in dorsal unpaired median neurons from the American cockroach Periplaneta americana. We show that Ae1a interacts with the domain II voltage sensor and that sensitivity to the toxin is conferred by natural sequence variations in the S1–S2 loop of domain II. The phyletic specificity of Ae1a provides crucial information for development of sodium channel insecticides that target key insect pests without harming beneficial species. PMID:27383378

  12. Molecular characterization and developmental expression of the gene encoding the prothoracicotropic hormone in the beet armyworm, Spodoptera exigua

    Institute of Scientific and Technical Information of China (English)

    XU Jun; SU JianYa; SHEN JinLiang; XU WeiHua

    2007-01-01

    Prothoracicotropic hormone (PTTH), a neuropeptide hormone stimulating the prothoracic glands to synthesize ecdysone, plays an important role in regulating postembryonic development in insects. The cDNA encoding PTTH was isolated and sequenced from the beet armyworm, Spodoptera exigua (Spe).The deduced amino acid sequence is composed of a signal peptide, a peptide (65 amino acids) of unknown function, and a mature PTTH molecule (111 amino acids). The Spe-PTTH shows similarities(45.5%-70.3%) to other known PTTHs reported in Lepidoptera species, but 7 cysteine residues and the hydrophobic regions were conserved. Whole-mount immunocytochemistry by using an antiserum against recombinant Helicoverpa armigera PTTH showed that Spe-PTTH was synthesized in two pairs of neurosecretory cells in the S. exigua brain. Northern blot analysis demonstrates the presence of a 1.2-kb transcript in the brain. The Spe-PTTH mRNA is detectable at high levels at the wandering larval stage, early pupal stage, and pharate adult stage, suggesting that the Spe-PTTH gene might be correlated with molting, metamorphosis, and reproduction.

  13. Insect Pest Incidence on Cowpea in the Cameroonian Southwest Forest and Western Derived Savanna Zones, their Contribution to Yield Loss in Foumbot and their Control

    Directory of Open Access Journals (Sweden)

    Parh, LA.

    1999-01-01

    Full Text Available In 1986 and 1987, insect pests sampled on cowpea in the Cameroonian Southwest forest and Western derived savanna ecological 1 zones included Maruca vitrata, Leguminivora (Cydia ptychora, Helicoverpa (Heliothis armigera, Melanagromyza vignalis, Apion disjunctum, Aphis craccivora, heteropteran bugs and bruchids. Under eight different deltamethrin spray schedules evaluated for their control at Foumbot, western derived savanna ecozone, the yield loss they caused ranged from 123.60 kg/ha in plants sprayed twice at the reproductive stage to 362.51 kg/ha in unsprayed plants in 1988 ; 21.86 kg/ha in plants sprayed thrice at the reproductive stage to 90.73 kg/ha in unsprayed plants in 1989 and 91.72 kg/ha in plants sprayed 5 to 6 times at fortnightly intervals, to 184.08 kg/ha in unsprayed plants in 1990. The percentage loss due to Maruca vitrata, Melanagromyza vignalis and heteropteran bugs was high in sprayed and unsprayed plots. In 1989 and 1990, seedyields were significantly increased by spraying deltamethrin either forthnightly or once at 75-100 % flowerbuds and once at 75-100 % podding, or once at 75-100 % flowering and once at 75-100 % podding.

  14. Comparison of Numbers of Cotton Bollworm Moths Caught in Water Traps Baited with Pheromone vs Blacklight Traps%性信息素水盆诱捕器和黑光灯诱捕棉铃虫成虫数量的比较

    Institute of Scientific and Technical Information of China (English)

    盛承发; 宣维健; 苏建伟; 王红托; 王德忠

    2001-01-01

    A comparison of moth catches of the cotton bollworm,Helicoverpa armigera (Hübner),in water tray traps(20~30×7~10cm) baited with synthetic sex pheromone vs blacklight traps (20w) was made at 3 locations in Shandong and Anhui Provinces,China in 1993 and 1996.The results show that male catches per trap per night in water traps were 4.18 and 2.49 times as many as that in blacklight traps at location 1 and 2,respectively.Both the differences were statistically significant (P<0.05).However,at location 3 the mean catches in water traps were only 56% of that in blacklight traps but the difference was not significant (P<0.40).It is seemed that the catching efficiency of water traps decreased with season and might be lower than that of blacklight traps in August and September.Therefore it is generally suitable to use the pheromone traps for monitoring of the bollworm population dynamics,especially during the overwintered and 1st generations (commonly during late April to early July in most China′s cotton areas).

  15. Cotton fertilization using PGPR Bacillus amyloliquefaciens FZB42 and compost: Impact on insect density and cotton yield in North Benin, West Africa

    Directory of Open Access Journals (Sweden)

    Thiery B. Charles Alavo

    2015-12-01

    Full Text Available This work has compared the effects of the biofertilizer Bacillus amyloliquefaciens FZB42 with that of compost for cotton production. The population dynamics of pests and predators have been studied in order to check whether the use of both fertilization materials can contribute to pest management in cotton. Three treatments were considered: (i dressing of seeds in rhizobacteria suspension, (ii introduction of rhizobacterial suspension directly in the pocket, same time with the seeds, and (iii fertilization with compost. The study was carried out in northwest Benin (West Africa. Results showed that cotton aphids, Aphis gossypii, pink bollworm, Pectinophora gossypiella, leaf roller, Sylepta derogata, and cotton bugs, Dysdercus sp. are the major insect pests encountered in the experimental plots. Cotton bollworm, Helicoverpa armigera, was present but under the economic threshold. The coccinellid predators, Cheilomenes spp., occurred in the experimental plots and almost suppressed aphid proliferation. Other natural enemies such as chrysopids and ant species also occurred and probably contributed to maintain the cotton bollworm under the economic threshold. The treatment with seeds dressed with the rhizobacteria suspension yielded 39% more cotton compared to the compost fertilization. The use of both fertilization materials without application of chemicals can contribute to pest management in cotton.

  16. Cyclic di-GMP contributes to adaption and virulence of Bacillus thuringiensis through a riboswitch-regulated collagen adhesion protein.

    Science.gov (United States)

    Tang, Qing; Yin, Kang; Qian, Hongliang; Zhao, Youwen; Wang, Wen; Chou, Shan-Ho; Fu, Yang; He, Jin

    2016-07-06

    Cyclic di-GMP is a ubiquitous second messenger that regulates diverse cellular processes in bacteria by binding to various protein or riboswitch effectors. In Bacillus thuringiensis BMB171, a c-di-GMP riboswitch termed Bc2 RNA resides in the 5'-untranslated region (5'-UTR) of an mRNA that encodes a collagen adhesion protein (Cap). The expression of cap was strongly repressed in parent strain BMB171 because of the presence of Bc2 RNA but was significantly promoted in the Bc2 RNA markerless deletion mutant. Bc2 RNA acts as a genetic "on" switch, which forms an anti-terminator structure to promote cap read-through transcription upon c-di-GMP binding. As a result, cap transcription was de-repressed under high c-di-GMP levels. Therefore, Bc2 RNA regulates cap expression using a repression/de-repression model. Bc2 RNA-regulated Cap was also found to be tightly associated with motility, aggregation, exopolysaccharide secretion, biofilm formation, and virulence of B. thuringiensis BMB171 against its host insect Helicoverpa armigera.

  17. The role of β18-β19 loop structure in insecticidal activity of Cry1Ac toxin from Bacillus thuringiensis

    Institute of Scientific and Technical Information of China (English)

    XIA LiQiu; WANG FaXiang; DING XueZhi; ZHAO XinMin; FU ZuJiao; QUAN MeiFang; YU ZiNiu

    2008-01-01

    The β18-β19 loop in domain Ⅲ of Cry1Ac toxin is unique among Bacillus thuringiensis Cry proteins. In this study, the role of the loop structure in insecticidal activity of Cry1Ac toxin was investigated. Alanine scanning mutations within the loop were initially generated and most mutants were over-expressed and reduced toxicity at different degrees, except mutant N546A that showed almost 2 times enhanced toxicity against Helicoverpa armigera larvae. Further mutagenic analysis of N546 re-vealed that a charged amino acid in this position would cause very unfavorable influence on insecti-cidal activity. In addition, the deletion of N546 led to protein instability because of destruction of the loop integrity. Besides, mutant W544F was much more toxic than W544Y, indicating that hydrophobic nature of the position was important for maintaining the stability and activity of Cry1Ac protein. These findings are the first biological evidence for a structural function of β18-β19 loop in insecticidal activity of the Cry1Ac toxin.

  18. Cloning, characterization and expression of a novel haplotype cry2A-type gene from Bacillus thuringiensis strain SWK1, native to Himalayan valley Kashmir.

    Science.gov (United States)

    Reyaz, A L; Arulselvi, P Indra

    2016-05-01

    Bacillus thuringiensis (Bt) is a gram positive bacterium which is effectively being used in pest management strategies as an eco-friendly bioinsecticide. In the present study a new cry2A gene was cloned from a promising indigenous B. thuringiensis SWK1 strain previously characterized for its toxicity against Spodoptera litura and Helicoverpa armigera larvae. The nucleotide sequence of the cloned cry2A gene pointed out that the open reading frame has 1902 bases encoding a polypeptide of 634 amino acid residues with a probable molecular weight of 70kDa. Homology comparisons showed that the deduced amino acid sequence of Cry2A had a similarity of 94% compared to that of the known Cry2Aa protein in the NCBI database and this gene has been named as cry2Al1 by the B. thuringiensis δ-endotoxin Nomenclature Committee. cry2Al1 was ligated into pET 22b vector and expressed in Escherichia coli BL21 (DE3) pLysS under the control of T7 promoter induced by isopropyl-beta-d-thiogalactopyranoside (IPTG). SDS-PAGE analysis confirmed the expression of cry2Al1 as ∼65kDa protein. Insect pest bioassays with neonate larvae of S. litura and H. armigera showed that the purified Cry2Al1 are toxic to S. litura and H. armigera with LC50 2.448μg/ml and H. armigera with 3.374μg/ml respectively.

  19. Molecular and Insecticidal Characterization of a Novel Cry-Related Protein from Bacillus Thuringiensis Toxic against Myzus persicae

    Science.gov (United States)

    Palma, Leopoldo; Muñoz, Delia; Berry, Colin; Murillo, Jesús; Ruiz de Escudero, Iñigo; Caballero, Primitivo

    2014-01-01

    This study describes the insecticidal activity of a novel Bacillus thuringiensis Cry-related protein with a deduced 799 amino acid sequence (~89 kDa) and ~19% pairwise identity to the 95-kDa-aphidicidal protein (sequence number 204) from patent US 8318900 and ~40% pairwise identity to the cancer cell killing Cry proteins (parasporins Cry41Ab1 and Cry41Aa1), respectively. This novel Cry-related protein contained the five conserved amino acid blocks and the three conserved domains commonly found in 3-domain Cry proteins. The protein exhibited toxic activity against the green peach aphid, Myzus persicae (Sulzer) (Homoptera: Aphididae) with the lowest mean lethal concentration (LC50 = 32.7 μg/mL) reported to date for a given Cry protein and this insect species, whereas it had no lethal toxicity against the Lepidoptera of the family Noctuidae Helicoverpa armigera (Hübner), Mamestra brassicae (L.), Spodoptera exigua (Hübner), S. frugiperda (J.E. Smith) and S. littoralis (Boisduval), at concentrations as high as ~3.5 μg/cm2. This novel Cry-related protein may become a promising environmentally friendly tool for the biological control of M. persicae and possibly also for other sap sucking insect pests. PMID:25384108

  20. Purification, characterization and evaluation of insecticidal activity of trypsin inhibitor from Albizia lebbeck seeds

    Institute of Scientific and Technical Information of China (English)

    Pratima Sharma; Amarjit K Nath; Reena Kumari; SV Bhardwaj

    2012-01-01

    A Bowman-Birk inhibitor with activity against gut protcases of Helicoverpa armigera was extracted in 0.1 M sodium phosphate buffer from defatted seed flour of Albizia lebbeck.It was purified to 29.62 folds with 51.43% re,very using ammonium sulfate precipitation,gel filtration chromatography on Sephadex G-100 column and ion exchange chromatography on DEAE-Sephadex A50.The purified protein had a molecular weight of 12,303 daltons as determined by SDS-PAGE.It was found to be heat stable up to 60℃ and had two pH optima of 7.5 and 9.0.The inhibitor exhibited non-competitive pattern of inhibition with a low Ki value of 0.2 μM.The inhibitor was found to be susceptible to varying concentrations of reducing agents like DTT and 2-mercaptoethanol,thereby indicating the role of disulphide bridges in maintaining its three dimensional structure and stability.The purified inhibitor caused mortality and suppressed larval growth of Pieris brassicae larvae.It was also found to be effective against gut trypsin extracted from Spodoptera littoralis.The sequence of the genes encoding for such inhibitors can be determined and the genes expressing protease inhibitors can be used in vegetable crops to confer resistance against insect pests and other plant pathogens.

  1. Activation of Bt Protoxin Cry1Ac in Resistant and Susceptible Cotton Bollworm.

    Directory of Open Access Journals (Sweden)

    Jizhen Wei

    Full Text Available Crystalline (Cry proteins from Bacillus thuringiensis (Bt are used extensively for insect control in sprays and transgenic plants, but their efficacy is reduced by evolution of resistance in pests. Here we evaluated reduced activation of Cry1Ac protoxin as a potential mechanism of resistance in the invasive pest Helicoverpa armigera. Based on the concentration killing 50% of larvae (LC50 for a laboratory-selected resistant strain (LF120 divided by the LC50 for its susceptible parent strain (LF, the resistance ratio was 1600 for Cry1Ac protoxin and 1200 for trypsin-activated Cry1Ac toxin. The high level of resistance to activated toxin as well as to protoxin indicates reduced activation of protoxin is not a major mechanism of resistance to Cry1Ac in LF120. For both insect strains, treatment with either the trypsin inhibitor N-a-tosyl-L-lysine chloromethyl ketone (TLCK or the chymotrypsin inhibitor N-a-tosyl-L-phenylalanine chloromethyl ketone (TPCK did not significantly affect the LC50 of Cry1Ac protoxin. Enzyme activity was higher for LF than LF120 for trypsin-like proteases, but did not differ between strains for chymotrypsin-like proteases. The results here are consistent with previous reports indicating that reduced activation of protoxin is generally not a major mechanism of resistance to Bt proteins.

  2. Activation of Bt Protoxin Cry1Ac in Resistant and Susceptible Cotton Bollworm.

    Science.gov (United States)

    Wei, Jizhen; Liang, Gemei; Wang, Bingjie; Zhong, Feng; Chen, Lin; Khaing, Myint Myint; Zhang, Jie; Guo, Yuyuan; Wu, Kongming; Tabashnik, Bruce E

    2016-01-01

    Crystalline (Cry) proteins from Bacillus thuringiensis (Bt) are used extensively for insect control in sprays and transgenic plants, but their efficacy is reduced by evolution of resistance in pests. Here we evaluated reduced activation of Cry1Ac protoxin as a potential mechanism of resistance in the invasive pest Helicoverpa armigera. Based on the concentration killing 50% of larvae (LC50) for a laboratory-selected resistant strain (LF120) divided by the LC50 for its susceptible parent strain (LF), the resistance ratio was 1600 for Cry1Ac protoxin and 1200 for trypsin-activated Cry1Ac toxin. The high level of resistance to activated toxin as well as to protoxin indicates reduced activation of protoxin is not a major mechanism of resistance to Cry1Ac in LF120. For both insect strains, treatment with either the trypsin inhibitor N-a-tosyl-L-lysine chloromethyl ketone (TLCK) or the chymotrypsin inhibitor N-a-tosyl-L-phenylalanine chloromethyl ketone (TPCK) did not significantly affect the LC50 of Cry1Ac protoxin. Enzyme activity was higher for LF than LF120 for trypsin-like proteases, but did not differ between strains for chymotrypsin-like proteases. The results here are consistent with previous reports indicating that reduced activation of protoxin is generally not a major mechanism of resistance to Bt proteins. PMID:27257885

  3. A challenge for the seed mixture refuge strategy in Bt maize: impact of cross-pollination on an ear-feeding pest, corn earworm.

    Directory of Open Access Journals (Sweden)

    Fei Yang

    Full Text Available To counter the threat of insect resistance, Bacillus thuringiensis (Bt maize growers in the U.S. are required to plant structured non-Bt maize refuges. Concerns with refuge compliance led to the introduction of seed mixtures, also called RIB (refuge-in-the-bag, as an alternative approach for implementing refuge for Bt maize products in the U.S. Maize Belt. A major concern in RIB is cross-pollination of maize hybrids that can cause Bt proteins to be present in refuge maize kernels and negatively affect refuge insects. Here we show that a mixed planting of 5% nonBt and 95% Bt maize containing the SmartStax traits expressing Cry1A.105, Cry2Ab2 and Cry1F did not provide an effective refuge for an important above-ground ear-feeding pest, the corn earworm, Helicoverpa zea (Boddie. Cross-pollination in RIB caused a majority (>90% of refuge kernels to express ≥ one Bt protein. The contamination of Bt proteins in the refuge ears reduced neonate-to-adult survivorship of H. zea to only 4.6%, a reduction of 88.1% relative to larvae feeding on ears of pure non-Bt maize plantings. In addition, the limited survivors on refuge ears had lower pupal mass and took longer to develop to adults.

  4. Pollen-mediated gene flow from transgenic cotton under greenhouse conditions is dependent on different pollinators.

    Science.gov (United States)

    Yan, Shuo; Zhu, Jialin; Zhu, Weilong; Li, Zhen; Shelton, Anthony M; Luo, Junyu; Cui, Jinjie; Zhang, Qingwen; Liu, Xiaoxia

    2015-01-01

    With the large-scale release of genetically modified (GM) crops, there are ecological concerns on transgene movement from GM crops to non-GM counterparts and wild relatives. In this research, we conducted greenhouse experiments to measure pollen-mediated gene flow (PGF) in the absence and presence of pollinators (Bombus ignitus, Apis mellifera and Pieris rapae) in one GM cotton (resistant to the insect Helicoverpa armigera and the herbicide glyphosate) and two non-GM lines (Shiyuan321 and Hai7124) during 2012 and 2013. Our results revealed that: (1) PGF varied depending on the pollinator species, and was highest with B. ignitus (10.83%) and lowest with P. rapae (2.71%); (2) PGF with B. ignitus depended on the distance between GM and non-GM cottons; (3) total PGF to Shiyuan321 (8.61%) was higher than to Hai7124 (4.10%). To confirm gene flow, we tested hybrids carrying transgenes for their resistance to glyphosate and H. armigera, and most hybrids showed strong resistance to the herbicide and insect. Our research confirmed that PGF depended on pollinator species, distance between plants and the receptor plant. PMID:26525573

  5. Identification of FXPRLamide Family Neuropeptides from the Japanese Oak Silkworm, Antheraea yamamai Using Immunocytochemistry Methods

    Institute of Scientific and Technical Information of China (English)

    WEI Zhao-jun; LAI Juan-hong; ZHAO Yuan

    2006-01-01

    In the present study, zooblooting, ELISA, and whole-mount immunocytochemistry methods were used to identify the FXPRLamide family neuropeptides from the Japanese oak silkworm, Antheraea yamamai. The results showed that the genomic DNA from A. yamamai showed positive bands after being hybridized with the fragment of DH-PBAN cDNA from Samia cynthia ricini, which was labeled with [α-32P]-dCTP. The SG showed highest FXPRLamide peptides titer in neural organs. Using an antiserum against Helicoverpa armigera PBAN, PBAN-like immunoreactivity was detected in the SG and TG of A. yamamai by whole-mount immunocytochemistry, and there were three cluster cells in the SG which shows positive PBAN-like immunoreactivity. The titers of FXPRLamide peptides immunoreactivity in the hemolymph were kept at a steady level. During pupation, the titer was increased promptly, but then decreased to a low level after the early pupal stage. The above-mentioned results demonstrate the existence of FXPRLamide family peptides in A. yamamai, but its function needs to be further investigated in the future.

  6. Molecular characterization and developmental expression of the gene encoding the prothoracicotropic hormone in the beet armyworm,Spodoptera exigua

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Prothoracicotropic hormone (PTTH), a neuropeptide hormone stimulating the prothoracic glands to synthesize ecdysone, plays an important role in regulating postembryonic development in insects. The cDNA encoding PTTH was isolated and sequenced from the beet armyworm, Spodoptera exigua (Spe). The deduced a?mino acid sequence is composed of a signal peptide, a peptide (65 amino acids) of un-known function, and a mature PTTH molecule (111 amino acids). The Spe-PTTH shows similarities (45.5%―70.3%) to other known PTTHs reported in Lepidoptera species, but 7 cysteine r?esidues and the hydrophobic regions were conserved. Whole-mount immunocytochemistry by using an antiserum against recombinant Helicoverpa armigera PTTH showed that Spe-PTTH was synthesized in two pairs of neurosecretory cells in the S. exigua brain. Northern blot analysis demonstrates the presence of a 1.2-kb transcript in the brain. The Spe-PTTH mRNA is detectable at high levels at the wandering larval stage, early pupal stage, and pharate adult stage, suggesting that the Spe-PTTH gene might be corre-lated with molting, metamorphosis, and reproduction.

  7. Are odorant-binding proteins involved in odorant discrimination?

    Science.gov (United States)

    Steinbrecht, R A

    1996-12-01

    Pheromone-sensitive sensilla trichodea of nine moth species belonging to six families and three superfamilies of Lepidoptera were immunolabelled with an antiserum against the pheromone-binding protein of Antheraea polyphemus. Strong immunolabelling of the sensillum lymph was observed in all long sensilla trichodea of A. polyphemus, A. pernyi (Saturniidae), Bombyx mori (Bombycidae) and Manduca sexta (Sphingidae). Very weak labelling was found with all sensilla trichodea of Dendrolimus kikuchii (Lasiocampidae) and Lymantria dispar (Lymantriidae). In three noctuid species, some long sensilla trichodea were labelled strongly, some only weakly and some were not labelled at all. The fraction of long sensilla trichodea that were strongly labelled was large in Helicoverpa armigera, but small in Spodoptera littoralis and Autographa gamma. The observed cross-reactivity was not correlated with taxonomic relatedness of the species but rather with chemical relatedness of the pheromones used by these species, as a high labelling density was consistently observed in sensilla tuned to pheromones with an alcyl chain of 16 carbon atoms. The highly divergent specificity of pheromone-receptor cells in Noctuidae appears to be mirrored by a similar diversity of the pheromone-binding proteins in the sensilla trichodea. These data support the notion that pheromone-binding proteins participate in odorant discrimination.

  8. Induction of a gloverin-like antimicrobial polypeptide in the sugarcane borer Diatraea saccharalis challenged by septic injury.

    Science.gov (United States)

    Silva, J L C; Barbosa, J F; Bravo, J P; Souza, E M de; Huergo, L F; Pedrosa, F O; Esteves, E; Daffre, S; Fernandez, M A

    2010-05-01

    Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) is an important pest for Brazilian sugarcane. In the present study, we detected two distinct spots in hemolymph from septic injured larvae (HDs1 and HDs2), which are separated by 2DE gel electrophoresis. Both spots were subjected to in-gel tryptic digestion and MALDI-TOF/TOF analysis, which revealed the sequence VFGTLGSDDSGLFGK present in both HDs1 and HDs2. This sequence had homology and 80% identity with specific Lepidoptera antimicrobial peptides called gloverins. Analyses using the ImageMaster 2D software showed pI 8.94 of the HDs1 spot, which is similar to that described to Hyalophora gloveri gloverin (pI 8.5). Moreover, the 14-kDa molecular mass of the spot HDs1 is compatible to that of gloverins isolated from the hemolymph of Trichoplusia ni, Helicoverpa armigera and H. gloveri. Antimicrobial assays with partially purified fractions containing the HDs1 and HDs2 polypeptides demonstrated activity against Escherichia coli. This is the first report of antimicrobial polypeptides in D. saccharalis, and the identification of these peptides may help in the generation of new strategies to control this pest.

  9. Are odorant-binding proteins involved in odorant discrimination?

    Science.gov (United States)

    Steinbrecht, R A

    1996-12-01

    Pheromone-sensitive sensilla trichodea of nine moth species belonging to six families and three superfamilies of Lepidoptera were immunolabelled with an antiserum against the pheromone-binding protein of Antheraea polyphemus. Strong immunolabelling of the sensillum lymph was observed in all long sensilla trichodea of A. polyphemus, A. pernyi (Saturniidae), Bombyx mori (Bombycidae) and Manduca sexta (Sphingidae). Very weak labelling was found with all sensilla trichodea of Dendrolimus kikuchii (Lasiocampidae) and Lymantria dispar (Lymantriidae). In three noctuid species, some long sensilla trichodea were labelled strongly, some only weakly and some were not labelled at all. The fraction of long sensilla trichodea that were strongly labelled was large in Helicoverpa armigera, but small in Spodoptera littoralis and Autographa gamma. The observed cross-reactivity was not correlated with taxonomic relatedness of the species but rather with chemical relatedness of the pheromones used by these species, as a high labelling density was consistently observed in sensilla tuned to pheromones with an alcyl chain of 16 carbon atoms. The highly divergent specificity of pheromone-receptor cells in Noctuidae appears to be mirrored by a similar diversity of the pheromone-binding proteins in the sensilla trichodea. These data support the notion that pheromone-binding proteins participate in odorant discrimination. PMID:8985600

  10. Herbivore defense responses and associated herbivore defense mechanism as revealed by comparing a resistant wild soybean with a susceptible cultivar

    Directory of Open Access Journals (Sweden)

    Xiaoyi Wang

    2015-12-01

    Full Text Available Plants have evolved sophisticated defense mechanisms against herbivores to help them adapt to the environment. Understanding the defense mechanisms in plants can help us control insects in a more effective manner. In this study, we found that compared with Tianlong 2 (a cultivated soybean with insect susceptibility, ED059 (a wild soybean line with insect resistance contains sharper pubescence tips, as well as lower transcript levels of wound-induced protein kinase (WIPK and salicylic acid-induced protein kinase (SIPK, which are important mitogen-activated protein kinases involved in early defense response to herbivores. The observed lower transcript levels of WIPK and SIPK induced higher levels of jasmonic acid (JA, JA biosynthesis enzymes (AOC3 and some secondary metabolites in ED059. Functional analysis of the KTI1 gene via Agrobacterium-mediated transformation in Arabidopsis thaliana indicated that it plays an important role in herbivore defense in ED059. We further investigated the molecular response of third-instar Helicoverpa armigera (Hübner larvae to Tianlong 2 and ED059. We found apoptotic cells only in the midguts of larvae that fed on ED059. Compared with larvae reared on the susceptible cultivar Tianlong 2, transcript levels of catalase (CAT and glutathione S-transferase (GST were up-regulated, whereas those of CAR, CHSB, and TRY were down-regulated in larvae that fed on the highly resistant variety ED059. We propose that these differences underlie the different herbivore defense responses of ED059 and Tianlong 2.

  11. Agrobacterium-mediated transformation in chickpea (Cicer arietinum L.) with an insecticidal protein gene: optimisation of different factors.

    Science.gov (United States)

    Indurker, Shivani; Misra, Hari S; Eapen, Susan

    2010-07-01

    Agrobacterium-mediated transformation in chickpea was developed using strain LBA4404 carrying nptII, uidA and cryIAc genes and transformants selected on Murashige and Skoog's basal medium supplemented with benzyladenine, kinetin and kanamycin. Integration of transgenes was demonstrated using polymerase chain reaction and Southern blot hybridization of T0 plants. The expression of CryIAc delta endotoxin and GUS enzyme was shown by enzyme linked immunosorbent assay and histochemical assay respectively. The transgenic plants (T0) showed more tolerance to infection by Helicoverpa armigera compared to control plants. Various factors such as explant source, cultivar type, different preculture treatment period of explants, co-cultivation period, acetosyringone supplementation, Agrobacterium harboring different plasmids, vacuum infiltration and sonication treatment were tested to study the influence on transformation frequency. The results indicated that use of epicotyl as explant, cultivar ICCC37, Agrobacterium harboring plasmid pHS102 as vector, preculture of explant for 48 h, co-cultivation period of 2 days at 25°C and vacuum infiltration for 15 min produced the best transformation results. Sonication treatment of explants with Agrobacteria for 80 s was found to increase the frequency of transformation.

  12. cDNA sequence, mRNA expression and genomic DNA of trypsinogen from the indianmeal moth, Plodia interpunctella.

    Science.gov (United States)

    Zhu, Y C; Oppert, B; Kramer, K J; McGaughey, W H; Dowdy, A K

    2000-02-01

    Trypsin-like enzymes are major insect gut enzymes that digest dietary proteins and proteolytically activate insecticidal proteins produced by the bacterium Bacillus thuringiensis (Bt). Resistance to Bt in a strain of the Indianmeal moth, Plodia interpunctella, was linked to the absence of a major trypsin-like proteinase (Oppert et al., 1997). In this study, trypsin-like proteinases, cDNA sequences, mRNA expression levels and genomic DNAs from Bt-susceptible and -resistant strains of the Indianmeal moth were compared. Proteinase activity blots of gut extracts indicated that the susceptible strain had two major trypsin-like proteinases, whereas the resistant strain had only one. Several trypsinogen-like cDNA clones were isolated and sequenced from cDNA libraries of both strains using a probe deduced from a conserved sequence for a serine proteinase active site. cDNAs of 852 nucleotides from the susceptible strain and 848 nucleotides from the resistant strain contained an open reading frame of 783 nucleotides which encoded a 261-amino acid trypsinogen-like protein. There was a single silent nucleotide difference between the two cDNAs in the open reading frame and the predicted amino acid sequence from the cDNA clones was most similar to sequences of trypsin-like proteinases from the spruce budworm, Choristoneura fumiferana, and the tobacco hornworm, Manduca sexta. The encoded protein included amino acid sequence motifs of serine proteinase active sites, conserved cysteine residues, and both zymogen activation and signal peptides. Northern blotting analysis showed no major difference between the two strains in mRNA expression in fourth-instar larvae, indicating that transcription was similar in the strains. Southern blotting analysis revealed that the restriction sites for the trypsinogen genes from the susceptible and resistant strains were different. Based on an enzyme size comparison, the cDNA isolated in this study corresponded to the gene for the smaller of two

  13. Heliothis virescens and Bt cotton in the United States.

    Science.gov (United States)

    Blanco, Carlos A

    2012-01-01

    The tobacco budworm (TBW), Heliothis virescens (F.), has been responsible for substantial economic losses, environmental pollution and a great challenge to the United States' economy, environment, researchers and cotton and tobacco producers during most of the past two hundred years. If a historical description of this pest problem should be written, it would necessarily be divided into two main events; the pre- and post-Bacillus thuringiensis-expressing (Bt)-cotton era. Before the advent of Bt-cotton, TBW had evolved resistance to most commercial insecticides, making cotton cultivation unfeasible at some point. Subsequently, a variety of clever control measures were developed in an effort to develop more sustainable integrated pest management programs. Without a doubt, Bt-cotton, transformed to produce insecticidal proteins from the soil borne bacterium, B. thuringiensis, is now one of the most important elements of TBW management in US cotton. This discussion could be quite short stating that Bt-cotton has produced an unprecedented level of control for TBW, but beyond this, it is important to note the additional impacts around the argument that Bt-cotton has likely reduced TBW populations over large areas-due to its high efficacy-to the low densities observed today. Cotton area suitable for TBW development has been reduced to ~40% of its pre Bt-cotton years and certainly may be another primary force behind this decline. However, the way we have detected this decline relies mostly on observations made in cotton fields, as well as males trapped in pheromone traps near cotton; these monitoring tools may not fully reflect TBW population levels at the landscape level. My argument supports what has been postulated before that TBW may be in the process of differentiating into "host races" and the cotton host race, once the most abundant in the environment, may be the one greatly affected by this habitat modification now dominated by Bt-cotton, while the other host races

  14. Pragas e inimigos naturais na soja e no milho cultivados em sistemas diversificados Pests and their natural enemies on soybean and corn grown in diversified systems

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    Francisco Jorge Cividanes

    2002-12-01

    Full Text Available A consorciação de culturas e o plantio direto podem influenciar a dinâmica populacional de insetos, aumentando ou diminuindo a densidade populacional de pragas e de inimigos naturais. Deste modo, avaliaram-se os efeitos de sistemas de plantio direto e da consorciação soja [Glycine max (L. Merrill] e milho (Zea mays L. sobre as populações de insetos-pragas e inimigos naturais. Os tratamentos constituíram um fatorial 3x2 (monocultura de soja, monocultura de milho, consorciação soja-milho em plantio direto e plantio convencional. Os insetos foram amostrados pelo método do pano, rede entomológica e procura visual. No milho, a ocorrência de insetos-pragas da parte aérea e insetos predadores não foi influenciada pelo manejo do solo. Lagartas de Helicoverpa zea ocorreram em maior número (5,1 no milho em consorciação. Na soja, adultos de Anticarsia gemmatalis e do predador Cycloneda sanguinea foram mais abundantes em plantio direto, respectivamente, 0,4 e 2,4 insetos. Observou-se maior número do sirfídeo Toxomerus sp. em plantio convencional (1,3. Nas condições de consorciação, verificou-se baixo número de Diabrotica gracilenta (11,5 na soja, enquanto que Maecolaspis sp. (5,0 e Megascelis sp. (17,0 e os predadores C. sanguinea (2,3, Doru sp. (0,8, Geocoris sp. (1,5 e Toxomerus sp. (1,4 ocorreram em alta densidade.Intercropping and no-tillage systems can affect the population dynamics of insects, increasing or decreasing the population density of pests and natural enemies. The objective of this study was to evaluate the effects of no-tillage and strip intercropping of soybean [Glycine max (L. Merrill] and corn (Zea mays L. on the abundance of insect pests and their natural enemies. Plots were arranged in a randomized complete block design in a 3 x 2 factorial experiment (soybean monoculture, corn monoculture, strip intercropping of soybean-corn under no-tillage and conventional tillage. Insects were sampled using sweep net

  15. Eficácia do indoxacarb para o controle de pragas em hortaliças Efficacy of indoxacarb in the control of vegetable pests

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    Samuel Martinelli

    2003-09-01

    Full Text Available A eficiência do indoxacarb foi avaliada no controle dos lepidópteros-pragas em hortaliças: Plutella xylostella (Lepidoptera: Yponeumatidae, Trichoplusia ni (Lepidoptera: Noctuidae, Neoleucinodes elegantalis (Lepidoptera: Pyralidae e Helicoverpa zea (Lepidoptera: Noctuidae. Os experimentos foram conduzidos em três locais diferentes nas culturas do repolho e tomate. Os inseticidas utilizados foram indoxacarb (no tomate de 2,4 a 6,0 g i.a./100 L e no repolho de 18 a 42 g i.a./ha, esfenvalerate (apenas no tomate de 1,75 g i.a./100 L, metomil (no tomate na dose de 21,5 g i.a./100 L e no repolho a 172 g i.a./ha, deltametrina (apenas no repolho na dose de 6 g i.a./ha e triflumuron (apenas no tomate na dose de 15 g i.a./100 L. Adotou-se o delineamento estatístico em blocos ao acaso com quatro repetições em todos os experimentos. Todas as doses avaliadas do produto indoxacarb apresentaram excelente desempenho no controle de P. xylostella e T. ni. Assim, a menor dose avaliada (18 g i.a./ha pode ser recomendada para o controle dessas pragas. Todos os produtos avaliados alcançaram níveis de eficiência maiores que 80% no controle de H. zea na cultura do tomate. Indoxacarb foi tão eficiente quanto o produto padrão adotado (triflumuron. N. elegantalis foi eficientemente controlada pelos inseticidas avaliados após nove aplicações, sendo que indoxacarb pode ser recomendado na menor dose utilizada (2,4 g i.a./100 L.The efficacy of indoxacarb was evaluated for controlling lepidopterous pests on vegetables: Plutella xylostella (Lepidoptera: Yponeumatidae, Trichoplusia ni (Lepidoptera: Noctuidae, Neoleucinodes elegantalis (Lepidoptera: Pyralidae, Helicoverpa zea (Lepidoptera: Noctuidae. The experiments were carried out at three different sites on cabbage and tomato crops. The utilized insecticides were indoxacarb (for tomato from 2.4 to 6.0 g a.i./100 L and for cabbage from 18 to 42 g i.a./ha, esfenvalerate (only for tomato at 1.75 g a.i./100 L

  16. Glyphosate tolerance and effects of cotton bollworms on transgenic herbicide and insect resistant cotton%转基因抗虫抗除草剂棉花对棉铃虫抗性及对草甘膦耐受性研究

    Institute of Scientific and Technical Information of China (English)

    牛建群; 朱家林; 张青文; 刘小侠

    2012-01-01

    The tolerance of genetically modified cotton to glyphosate herbicides and its resistance to the cotton bollworm was investigated. The cotton had good tolerance to glyphusates. Growth was normal after spraying with glyphosate during the "four leaf" stage but spraying during the budding period may reduce the flowering and boll formation. This cotton variety and a control (a transgenic insect - resistant cotton) displayed good resistance to the cotton bollworm. The top leaves of the seeding stage were the most resistant but resistance declined to 49. 2% and 46. 6% with the growth of the cotton. During the boll opening stage resistance improved to 57.0% and 53.1% respectively.%本论文研究了抗虫又抗除草剂棉花对草甘膦的耐受程度,比较了这一双抗性状的棉花与单抗虫棉的抗虫效果.结果表明,抗虫又抗除草剂棉花对草甘膦有较好的耐受性,四叶期喷施草甘膦后抗虫抗除草剂棉花可以安全生长,蕾期喷施草甘膦对棉花的开花率和结铃率有影响.抗虫又抗除草剂棉花和单抗虫棉对棉铃虫Helicoverpa armigera(Hübner)均具有较好的防治效果,苗期棉花叶片对棉铃虫防治效果最好,后期防治效果下降到49.2%和46.6%,吐絮期防治效果又上升到57.0%和53.1%.

  17. Genomewide transcriptional signatures of migratory flight activity in a globally invasive insect pest.

    Science.gov (United States)

    Jones, Christopher M; Papanicolaou, Alexie; Mironidis, George K; Vontas, John; Yang, Yihua; Lim, Ka S; Oakeshott, John G; Bass, Chris; Chapman, Jason W

    2015-10-01

    Migration is a key life history strategy for many animals and requires a suite of behavioural, morphological and physiological adaptations which together form the 'migratory syndrome'. Genetic variation has been demonstrated for many traits that make up this syndrome, but the underlying genes involved remain elusive. Recent studies investigating migration-associated genes have focussed on sampling migratory and nonmigratory populations from different geographic locations but have seldom explored phenotypic variation in a migratory trait. Here, we use a novel combination of tethered flight and next-generation sequencing to determine transcriptomic differences associated with flight activity in a globally invasive moth pest, the cotton bollworm Helicoverpa armigera. By developing a state-of-the-art phenotyping platform, we show that field-collected H. armigera display continuous variation in flight performance with individuals capable of flying up to 40 km during a single night. Comparative transcriptomics of flight phenotypes drove a gene expression analysis to reveal a suite of expressed candidate genes which are clearly related to physiological adaptations required for long-distance flight. These include genes important to the mobilization of lipids as flight fuel, the development of flight muscle structure and the regulation of hormones that influence migratory physiology. We conclude that the ability to express this complex set of pathways underlines the remarkable flexibility of facultative insect migrants to respond to deteriorating conditions in the form of migratory flight and, more broadly, the results provide novel insights into the fundamental transcriptional changes required for migration in insects and other taxa. PMID:26331997

  18. Genome-wide transcriptomic and proteomic analyses of bollworm-infested developing cotton bolls revealed the genes and pathways involved in the insect pest defence mechanism.

    Science.gov (United States)

    Kumar, Saravanan; Kanakachari, Mogilicherla; Gurusamy, Dhandapani; Kumar, Krishan; Narayanasamy, Prabhakaran; Kethireddy Venkata, Padmalatha; Solanke, Amolkumar; Gamanagatti, Savita; Hiremath, Vamadevaiah; Katageri, Ishwarappa S; Leelavathi, Sadhu; Kumar, Polumetla Ananda; Reddy, Vanga Siva

    2016-06-01

    Cotton bollworm, Helicoverpa armigera, is a major insect pest that feeds on cotton bolls causing extensive damage leading to crop and productivity loss. In spite of such a major impact, cotton plant response to bollworm infection is yet to be witnessed. In this context, we have studied the genome-wide response of cotton bolls infested with bollworm using transcriptomic and proteomic approaches. Further, we have validated this data using semi-quantitative real-time PCR. Comparative analyses have revealed that 39% of the transcriptome and 35% of the proteome were differentially regulated during bollworm infestation. Around 36% of significantly regulated transcripts and 45% of differentially expressed proteins were found to be involved in signalling followed by redox regulation. Further analysis showed that defence-related stress hormones and their lipid precursors, transcription factors, signalling molecules, etc. were stimulated, whereas the growth-related counterparts were suppressed during bollworm infestation. Around 26% of the significantly up-regulated proteins were defence molecules, while >50% of the significantly down-regulated were related to photosynthesis and growth. Interestingly, the biosynthesis genes for synergistically regulated jasmonate, ethylene and suppressors of the antagonistic factor salicylate were found to be up-regulated, suggesting a choice among stress-responsive phytohormone regulation. Manual curation of the enzymes and TFs highlighted the components of retrograde signalling pathways. Our data suggest that a selective regulatory mechanism directs the reallocation of metabolic resources favouring defence over growth under bollworm infestation and these insights could be exploited to develop bollworm-resistant cotton varieties. PMID:26799171

  19. Environmental Factors in the Growth of Jatropha at Potorono Village, Yogyakarta

    Directory of Open Access Journals (Sweden)

    Mohammad Nurcholis

    2015-01-01

    Full Text Available Jatropha curcas is a perennial crop that has been known by Indonesian people for more than seven decades as a plant that produces renewable biofuel. In the present decade, plants producing biofuel are expected to be developed to overcome the lowering nonrenewable fuel reserves. There is a myth that jatropha can grow well on marginal lands and draught condition, perform well on non-fertile soils, no need for agronomic management and is resistant to plant pests and diseases. This study was conducted to identify the environmental factors that influenced the growth of jatropha on the marginal land at Potorono village, Yogyakarta Province, Indonesia. Jatropha has been planted by local people at the village road sides and on the marginal land field at the local governmental land in this village. They grew jatropha on these areas with the purpose of preventing competition of area utilization with food crops. The results showed that the growth of jatropha was restricted by low content of organic matter, plant nutrition and poor soil drainage. Applications of manure and macro nutrients (N, P and K to this crop were able to increase crop performance. The number of shoots, flowers and fruit bunches increased by manure and nutrients treatments. Field observation showed that there were several plant pests, such as Aspidiotus sp., Paracoccus marginatus, Poliphagotarsonemus latus, Selenothrips rubrocinctus, Chrysochoris javanus, Valanga nigricornis, Chloracris prasina, and Helicoverpa armigera that attacked plant leaves and fruits. There were plant leaf necrotic symptoms that caused by plant pathogens were also observed. The diseases are bacterial leaf spot (Xanthomonas ricinicola, cercospora leaf spot (Cercospora ricinella and rust (Phakopsora jatrophicola. Thus, jatropha is like any other plants that need a good agro-ecological condition to grow well and produce high yield.

  20. Characterization of a single-nucleocapsid nucleopolyhedrovirus of Thysanoplusia orichalcea L. (Lepidoptera: Noctuidae) from Indonesia.

    Science.gov (United States)

    Cheng, X W; Carner, G R

    2000-05-01

    A single-nucleocapsid nucleopolyhedrovirus (NPV) isolated from Thysanoplusia orichalcea L. (Lepidoptera:Noctuidae) (ThorNPV) in Indonesia has tetrahedral occlusion bodies (OBs) with a width of 1. 22 microm (range = 0.803-1.931 microm). The length of the virion with an envelope averaged 0.29 and 0.23 microm without an envelope. ThorNPV was propagated in Pseudoplusia includens (Walker) and its authenticity was confirmed by sequence analysis of the polyhedrin gene of the ThorNPV produced in T. orichalcea and P. includens. Polyhedrin amino acid sequence analysis revealed that ThorNPV belongs to Group II of baculoviruses and is closely related to Trichoplusia ni single nucleocapsid NPV, sharing 97.6% sequence identity. Infectivity of ThorNPV against third instar P. includens was low, with a LD(50) value of 65,636 OBs/larva. Electron microscopy of infected tissues showed many polyhedra without virions embedded, which might explain the low virulence against P. includens. Differences in virion occlusion rates between individual cells in the same tissue suggested that the inoculum consisted of at least two variants that differed in the gene(s) controlling virion occlusion. In a host range test using the LD(50) value to P. includens against Spodoptera exigua, S. frugiperda, S. eridania, Anticarsia gemmatalis, Helicoverpa zea, Trichoplusia ni, and P. includens, P. includens was the only species infected. The virus infected primarily the fat body, tracheal epithelium, and hypodermis. The genomic size of the ThorNPV is 135 kb. PMID:10843835

  1. Biological and molecular characterization of a multicapsid nucleopolyhedrovirus from Thysanoplusia orichalcea (L.) (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Cheng, Xiao-Wen; Carner, Gerald R; Lange, Martin; Jehle, Johannes A; Arif, Basil M

    2005-02-01

    A multicapsid nucleopolyhedrovirus (ThorMNPV) that was co-isolated with a single nucleocapid ThorSNPV from mixed infected larvae of Thysanoplusia orichalcea L. (Lepidoptea: Noctuidae) is characterized. Scanning electron microscopy of ThorMNPV showed a dodecahedral-shaped occlusion body (OB). The occluded virions contained one to as many as eight nucleocapsids/virion. Virion band profiles in gradient centrifugation were consistent in at least 10 rounds of centrifugation from different virion sample preparations. The ThorMNPV had high virulence to third instar Trichoplusia ni and Pseudoplusia includens with LD50 values of 17 and 242OBs per larva, respectively. However, ThorMNPV did not cause mortality in Spodoptera exigua, Spodoptera frugiperda, Spodoptera eridania, Anticarsia gemmatalis, and Helicoverpa zea. ThorMNPV replicates in cells of various tissues such as the fat body and tracheal epithelium cells. T. ni High 5 cells were permissive to ThorMNPV in terms of infection and viral DNA transfection, but SF-21 was less permissive and the infection process was slower. Production of OBs by ThorMNPV in the nuclei of SF-21 was not well pronounced. The genome size of ThorMNPV was estimated to be 136 kb. The polyhedrin gene open reading frame (ORF) was cloned and completely sequenced. The promoter sequence is identical to that of Autographa californica MNPV. Phylogenetic analyses using partial sequences of the polh, lef-8, and lef-9 revealed that ThorMNPV is a member of the Group I NPVs and is related but distinct from the AcMNPV/Rachiplusia ou NPV/Bombyx mori NPV cluster. PMID:15766929

  2. Comparison of field-collected ascovirus isolates by DNA hybridization, host range, and histopathology.

    Science.gov (United States)

    Hamm, J J; Styer, E L; Federici, B A

    1998-09-01

    Six field-collected ascovirus isolates obtained from five noctuid species in the continental United States were compared with respect to the general relatedness of their DNA, host range, and histopathology. Two isolates were from Spodoptera frugiperda, and the other four were from Autographa precationis, Heliothis virescens, Helicoverpa zea, and Trichoplusia ni. DNA-DNA hybridization studies showed that the six isolates belonged to three distinct viral species, with the isolates from S. frugiperda composing one species, those from A. precationis and H. virescens a second species, and those from H. zea and T. ni a third species. The host range and histopathology of each isolate was studied in eight noctuid species, S. frugiperda, Spodoptera ornithogalli, Spodoptera exigua, Spodoptera eridania, H. virescens, H. zea, A. precationis, and Feltia subterranea. Though some variation existed between the different isolates of each viral species, distinct patterns were apparent for each. The viral species from S. frugiperda had a host range that was limited primarily to Spodoptera species and both isolates of this virus only replicated and caused significant pathology in the fat body, whereas the viral species from A. precationis and H. virescens had a much broader host range that included most of the species tested, but also had a tissue tropism primarily restricted to the fat body. The viral species from T. ni and H. zea readily infected all the hosts tested, where the principal site of replication and significant pathology was the epidermis. In many test hosts, however, this viral species also replicated and caused significant pathology in the tracheal epithelium and to a lesser extent in the fat body. Aside from contributing to knowledge of ascovirus biology, these studies indicate that DNA hybridization profiles combined with studies of host range and tissue tropism can be used as characters for defining ascovirus species. PMID:9709014

  3. Intraguild Competition of Three Noctuid Maize Pests.

    Science.gov (United States)

    Bentivenha, J P F; Baldin, E L L; Hunt, T E; Paula-Moraes, S V; Blankenship, E E

    2016-08-01

    The western bean cutworm Striacosta albicosta (Smith), the fall armyworm Spodoptera frugiperda (J. E. Smith), and the corn earworm Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) are among the major lepidopteran pests of maize in the United States, belonging to the same guild and injuring the reproductive tissues of this crop. Here, intraguild competition of these lepidopterans on non-Bt maize was evaluated through survival analysis of each species under laboratory and field conditions. Competition scenarios were carried out in arenas containing maize silk or ear tissue, using larvae on different stadium of development. Fitness cost competition studies were conducted to examine the influence of intraguild competition and cannibalism and predation rates on larval development. The survival of S. albicosta competing with the other species was significantly lower than in intraspecific competition, even when the larvae were more developed than the competitor. For S. frugiperda, survival remained high in the different competition scenarios, except when competing in a smaller stadium with H. zea Larvae of H. zea had a high rate of cannibalism, higher survival when competing against S. albicosta than S. frugiperda, and reduced survival when the H. zea larvae were at the same development stadium or smaller than the competitors. Based on fitness cost results, the absence of a competitor for the feeding source may confer an advantage to the larval development of S. frugiperda and H. zea Our data suggest that S. frugiperda has a competitive advantage against the other species, while S. albicosta has the disadvantage in the intraguild competition on non-Bt maize.

  4. Early warning of cotton bollworm resistance associated with intensive planting of Bt cotton in China.

    Directory of Open Access Journals (Sweden)

    Haonan Zhang

    Full Text Available Transgenic crops producing Bacillus thuringiensis (Bt toxins kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The predominant strategy for delaying pest resistance to Bt crops requires refuges of non-Bt host plants to promote survival of susceptible pests. To delay pest resistance to transgenic cotton producing Bt toxin Cry1Ac, farmers in the United States and Australia planted refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. Here we report data from a 2010 survey showing field-evolved resistance to Cry1Ac of the major target pest, cotton bollworm (Helicoverpa armigera, in northern China. Laboratory bioassay results show that susceptibility to Cry1Ac was significantly lower in 13 field populations from northern China, where Bt cotton has been planted intensively, than in two populations from sites in northwestern China where exposure to Bt cotton has been limited. Susceptibility to Bt toxin Cry2Ab did not differ between northern and northwestern China, demonstrating that resistance to Cry1Ac did not cause cross-resistance to Cry2Ab, and implying that resistance to Cry1Ac in northern China is a specific adaptation caused by exposure to this toxin in Bt cotton. Despite the resistance detected in laboratory bioassays, control failures of Bt cotton have not been reported in China. This early warning may spur proactive countermeasures, including a switch to transgenic cotton producing two or more toxins distinct from Cry1A toxins.

  5. Multifaceted effects of host plants on entomopathogenic nematodes.

    Science.gov (United States)

    Hazir, Selcuk; Shapiro-Ilan, David I; Hazir, Canan; Leite, Luis G; Cakmak, Ibrahim; Olson, Dawn

    2016-03-01

    The success of parasites can be impacted by multi-trophic interactions. Tritrophic interactions have been observed in parasite-herbivore-host plant systems. Here we investigate aspects of multi-trophic interactions in a system involving an entomopathogenic nematode (EPN), its insect host, and host plant. Novel issues investigated include the impact of tritrophic interactions on nematode foraging behavior, the ability of EPNs to overcome negative tritrophic effects through genetic selection, and interactions with a fourth trophic level (nematode predators). We tested infectivity of the nematode, Steinernema riobrave, to corn earworm larvae (Helicoverpa zea) in three host plants, tobacco, eggplant and tomato. Tobacco reduced nematode virulence and reproduction relative to tomato and eggplant. However, successive selection (5 passages) overcame the deficiency; selected nematodes no longer exhibited reductions in phenotypic traits. Despite the loss in virulence and reproduction nematodes, first passage S. riobrave was more attracted to frass from insects fed tobacco than insects fed on other host plants. Therefore, we hypothesized the reduced virulence and reproduction in S. riobrave infecting tobacco fed insects would be based on a self-medicating tradeoff, such as deterring predation. We tested this hypothesis by assessing predatory success of the mite Sancassania polyphyllae and the springtail Sinella curviseta on nematodes reared on tobacco-fed larvae versus those fed on greater wax moth, Galleria mellonella, tomato fed larvae, or eggplant fed larvae. No advantage was observed in nematodes derived from tobacco fed larvae. In conclusion, our results indicated that insect-host plant diet has an important effect on nematode foraging, infectivity and reproduction. However, negative host plant effects, might be overcome through directed selection. We propose that host plant species should be considered when designing biocontrol programs using EPNs. PMID:26896698

  6. Study of the pest community of velvetleaf (Abutilon theophrasti Medic.).

    Science.gov (United States)

    Nagy, V; Keresztes, B; Nádasy, E

    2011-01-01

    Velvetleaf (Abutilon theophrasti Medicus 1787) is one of the most economically threatening weed plant in Hungary. Researching biological control against it, and identifying a possible and effective biocontrol agent is an important challenge, as chemical control is difficult and expensive, and there is an increasing claim to practice slight plant protection. Entomological studies were made in several parts of the world, for evaluating the species, occuring in velvetleaf, but none of these kind of experiments were assessed in Hungary. Our observations were made in field and plastic boxes, both under open field circumstances in 2008 and 2009 by visually assessing pests, netting and damage based identifying. Meanwhile 8 pest species were identified, including (Helix pomatia Linnaeus 1758--roman snale; Trialeurodes vaporariorum (Westwood 1856)--greenhouse whitefly; Oxycarenus lavaterae (Fabricius 1787)-- lime seed bug; Pyrrhocoris apterus (Linnaeus 1758)--fire bug; Rhopalus parumpunctatus Schilling 1829--common hyaline bug; Liorhyssus hyalinus--hyaline grass bug (Fabricius 1794); Mamestra brassicae (Linnaeus 1758)--cabbage moth; Helicoverpa armigera (Hübner 1808)--corn earworm). On the whole the literature datas were enlarged with four new velvetleaf pests (roman scale, lime seed bug, common hyaline bug, cabbage moth). Considering the earlier literature and our results, Liorhyssus hyalinus may play an important role on biological management of velvetleaf. However this pest considered as polyphagous, but discovered to occur in great numbers on velvetleaf, this points to the fact that can be its main host plant and by sucking on the plant, can cause decreased germination rate. We suggest the "hyaline velvetleaf bug" name istead of "hyaline grass bug". Of course, additional experiments are needed on this pest to may use safety and effectively in the future.

  7. Non-recessive Bt toxin resistance conferred by an intracellular cadherin mutation in field-selected populations of cotton bollworm.

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    Haonan Zhang

    Full Text Available Transgenic crops producing Bacillus thuringiensis (Bt toxins have been planted widely to control insect pests, yet evolution of resistance by the pests can reduce the benefits of this approach. Recessive mutations in the extracellular domain of toxin-binding cadherin proteins that confer resistance to Bt toxin Cry1Ac by disrupting toxin binding have been reported previously in three major lepidopteran pests, including the cotton bollworm, Helicoverpa armigera. Here we report a novel allele from cotton bollworm with a deletion in the intracellular domain of cadherin that is genetically linked with non-recessive resistance to Cry1Ac. We discovered this allele in each of three field-selected populations we screened from northern China where Bt cotton producing Cry1Ac has been grown intensively. We expressed four types of cadherin alleles in heterologous cell cultures: susceptible, resistant with the intracellular domain mutation, and two complementary chimeric alleles with and without the mutation. Cells transfected with each of the four cadherin alleles bound Cry1Ac and were killed by Cry1Ac. However, relative to cells transfected with either the susceptible allele or the chimeric allele lacking the intracellular domain mutation, cells transfected with the resistant allele or the chimeric allele containing the intracellular domain mutation were less susceptible to Cry1Ac. These results suggest that the intracellular domain of cadherin is involved in post-binding events that affect toxicity of Cry1Ac. This evidence is consistent with the vital role of the intracellular region of cadherin proposed by the cell signaling model of the mode of action of Bt toxins. Considered together with previously reported data, the results suggest that both pore formation and cell signaling pathways contribute to the efficacy of Bt toxins.

  8. Expression and purification of virus like particles (VLPs) of foot-and-mouth disease virus in Eri silkworm (Samia cynthia ricini) larvae.

    Science.gov (United States)

    Kumar, Manoj; Saravanan, P; Jalali, S K

    2016-03-01

    Foot-and-mouth disease (FMD) is a highly contagious viral disease, which causes severe economic loss to livestock. Virus like particles (VLPs) produced by recombinant DNA technology are gaining importance because of their immunogenic properties and safety in developing a new vaccine for FMD. In the present study, a practical and economically feasible approach of expression, purification and characterization of VLPs of FMDV in Eri silkworm (Samia cynthia ricini) larvae was described. Although three lepidopteran insect larvae (Helicoverpa armigera, Spodoptera litura and Samia cynthia ricini) were tested for production of VLPs, expression was obtained only in Eri silkworm larvae. High titred recombinant baculovirus encoding the polyprotein P1-2A-3C of FMDV was prepared in Sf9 cells. Injection of recombinant baculovirus into hemocoel of Eri silkworm larvae resulted in increasing levels of expression of VLPs in the hemolymph from 3 to 7 days post infection (dpi) compared to low level expression by oral feeding. The VLPs reacted in Sandwich ELISA with serum raised against whole virus particles of FMDV type O/IND/R2/75 and protein banding pattern of 26, 37 and 47 kDa in Western blotting demonstrated their antigenic resemblance to native virus. Sucrose density gradient purified VLPs were used for immunization of rabbits and guinea pigs for assessing immunogenicity. Further, the reactivity of serum samples of rabbits and guinea pigs in Indirect-ELISA with titres (1.30-2.81 Log10) indicated that the VLPs were antigenic and immunogenic in nature. We demonstrate that Eri silkworm larvae could be used for production of VLPs of FMDV type O/IND/R2/75 for the first time. This approach could be useful for large scale production of recombinant VLPs for vaccine or diagnostic use in FMD control programme. PMID:26925448

  9. Two Year Field Study to Evaluate the Efficacy of Mamestra brassicae Nucleopolyhedrovirus Combined with Proteins Derived from Xestia c-nigrum Granulovirus

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    Chie Goto

    2015-03-01

    Full Text Available Japan has only three registered baculovirus biopesticides despite its long history of studies on insect viruses. High production cost is one of the main hindrances for practical use of baculoviruses. Enhancement of insecticidal effect is one possible way to overcome this problem, so there have been many attempts to develop additives for baculoviruses. We found that alkaline soluble proteins of capsules (GVPs of Xestia c-nigrum granulovirus can increase infectivity of some viruses including Mamestra brassicae nucleopolyhedrovirus (MabrNPV, and previously reported that MabrNPV mixed with GVPs was highly infectious to three important noctuid pests of vegetables in the following order, Helicoverpa armigera, M. brassicae, and Autographa nigrisigna. In this study, small-plot experiments were performed to assess concentrations of MabrNPV and GVPs at three cabbage fields and a broccoli field for the control of M. brassicae. In the first experiment, addition of GVPs (10 µg/mL to MabrNPV at 106 OBs/mL resulted in a significant increase in NPV infection (from 53% to 66%. In the second experiment, the enhancing effect of GVP on NPV infection was confirmed at 10-times lower concentrations of MabrNPV. In the third and fourth experiments, a 50% reduction in GVPs (from 10 µg/mL to 5 µg/mL did not result in a lowering of infectivity of the formulations containing MabrNPV at 105 OBs/mL. These results indicate that GVPs are promising additives for virus insecticides.

  10. Pest-managing activities of plant extracts and anthraquinones from Cassia nigricans from Burkina Faso.

    Science.gov (United States)

    Georges, Kambou; Jayaprakasam, Bolleddula; Dalavoy, Sanjeev S; Nair, Muraleedharan G

    2008-04-01

    Insecticidal activity of eight plants collected from Burkina Faso was studied using mosquito (Ochlerotatus triseriatus), Helicoverpa zea and Heliothis virescens larvae and adult white fly (Bemisia tabaci). The n-hexane, ethyl acetate and methanol extracts of Pseudocedrela kotschyi, Strophantus hispidus, Securidaca longepedunculata, Sapium grahamii, Swartzia madagascariensis, Cassia nigricans, Jatropha curcas and Datura innoxia were used in this study. Extracts were tested at 250 microg/mL concentration. All three extracts of C. nigricans, J. curcas (skin and seeds) and D. innoxia exhibited 100% mortality on fourth instar mosquito (O. triseriatus) larvae. In addition, the n-hexane and ethyl acetate extracts of S. hispidus, S. longepedunculata, S. grahamii showed 100% mortality. The ethyl acetate extract of S. madagascariensis was the most active on adult white fly and exhibited 80% mortality. Extracts of all other plants exhibited 30-50% mortality on B. tabaci. In the antifeedant assays against H. zea and H. virescens, the MeOH extracts of C. nigricans, S. madagascarensis and S. hispidus were more effective against H. zea as indicated by 74% larval weight reduction as compared to the control. Since C. nigricans is commonly used in West Africa to protect grain storage from insects, we have characterized the insecticidal components present in its extract. Bioassay directed isolation of C. nigricans leaf extract yielded anthraquinones emodin, citreorosein, and emodic acid and a flavonoid, luteolin. Emodin, the most abundant and active anthraquinone in C. nigricans showed approximately 85% mortality on mosquito larvae Anopheles gambiaea and adult B. tabaci at 50 and 25 microg/mL, respectively, in 24 h. These results suggest that the extract of C. nigricans has the potential to be used as an organic approach to manage some of the agricultural pests. PMID:17478091

  11. Pheromone Lure and Trap Color Affects Bycatch in Agricultural Landscapes of Utah.

    Science.gov (United States)

    Spears, Lori R; Looney, Chris; Ikerd, Harold; Koch, Jonathan B; Griswold, Terry; Strange, James P; Ramirez, Ricardo A

    2016-08-01

    Aerial traps, using combinations of color and attractive lures, are a critical tool for detecting and managing insect pest populations. Yet, despite improvements in trap efficacy, collection of nontarget species ("bycatch") plagues many insect pest surveys. Bycatch can influence survey effectiveness by reducing the available space for target species and increasing trap screening time, especially in areas where thousands of insects are captured as bycatch in a given season. Additionally, bycatch may negatively impact local nontarget insect populations, including beneficial predators and pollinators. Here, we tested the effect of pheromone lures on bycatch rates of Coccinellidae (Coleoptera), Apoidea (Hymenoptera), and nontarget Lepidoptera. Multicolored (primarily yellow and white) bucket traps containing a pheromone lure for capturing one of three survey target species, Spodoptera litura (F.), S. littoralis (Boisduval), or Helicoverpa armigera (Hübner), were placed in alfalfa and corn fields, and compared to multicolored traps without a pheromone lure. All-green traps with and without H. armigera lures were employed in a parallel study investigating the effect of lure and trap color on bycatch. Over 2,600 Coccinellidae representing seven species, nearly 6,400 bees in 57 species, and >9,000 nontarget moths in 17 genera were captured across 180 traps and seven temporal sampling events. Significant effects of lure and color were observed for multiple taxa. In general, nontarget insects were attracted to the H. armigera lure and multicolored trap, but further studies of trap color and pheromone lure specificity are needed to better understand these interactions and to minimize nontarget captures.

  12. Evaluation of total phenolic compounds and insecticidal and antioxidant activities of tomato hairy root extract.

    Science.gov (United States)

    Singh, Harpal; Dixit, Sameer; Verma, Praveen Chandra; Singh, Pradhyumna Kumar

    2014-03-26

    Tomatoes are one of the most consumed crops in the whole world because of their versatile importance in dietary food as well as many industrial applications. They are also a rich source of secondary metabolites, such as phenolics and flavonoids. In the present study, we described a method to produce these compounds from hairy roots of tomato (THRs). Agrobacterium rhizogenes strain A4 was used to induce hairy roots in the tomato explants. The Ri T-DNA was confirmed by polymerase chain reaction amplification of the rolC gene. Biomass accumulation of hairy root lines was 1.7-3.7-fold higher compared to in vitro grown roots. Moreover, THRs efficiently produced several phenolic compounds, such as rutin, quercetin, kaempferol, gallic acid, protocatechuic acid, ferulic acid, colorogenic acid, and caffeic acid. Gallic acid [34.02 μg/g of dry weight (DW)] and rutin (20.26 μg/g of DW) were the major phenolic acid and flavonoid produced by THRs, respectively. The activities of reactive oxygen species enzymes (catalase, ascorbate peroxidase, and superoxide dismutase) were quantified. The activity of catalase in THRs was 0.97 ± 0.03 mM H2O2 min(-1) g(-1), which was 1.22-fold (0.79 ± 0.09 mM H2O2 min(-1) g(-1)) and 1.59-fold (0.61 ± 0.06 mM H2O2 min(-1) g(-1)) higher than field grown and in vitro grown roots, respectively. At 100 μL/g concentration, the phenolic compound extract caused 53.34 and 40.00% mortality against Helicoverpa armigera and Spodoptera litura, respectively, after 6 days. Surviving larvae of H. armigera and S. litura on the phenolic compound extract after 6 days showed 85.43 and 86.90% growth retardation, respectively. PMID:24635720

  13. Effects of Interplanting Flowering Plants on the Biological Control of Corn Earworm (Lepidoptera: Noctuidae) and Thrips (Thysanoptera: Thripidae) in Sweet Corn.

    Science.gov (United States)

    Manandhar, Roshan; Wright, Mark G

    2016-02-01

    Natural enemy exploitation of food resources and alternative hosts in noncrop vegetation has been shown to be an effective means of enhancing natural enemy populations in diversified agro-ecosystem. Field trials were conducted in Hawaii to examine effects of interplanting flowering plants on 1) parasitism of corn earworm, Helicoverpa zea (Boddie) eggs by Trichogramma spp., and 2) abundance of Orius spp. in relation to prey (H. zea eggs and thrips [primarily, Frankliniella occidentalis (Pergande) and Frankliniella williamsi Hood]). Sweet corn (maize), Zea mays L., was interplanted with three flowering plants, buckwheat, Fagopyrum esculentum Moench, cowpea, Vigna unguiculata (L.), and sunn hemp, Crotolaria juncea L., at 2:1 and 4:1 (corn: flowering plant) ratios in 2009 and 2010, respectively. In 2009, the abundance of Orius spp. was significantly greater in the buckwheat-interplanted treatment compared to the monocrop control at similar levels of prey availability, indicating buckwheat flowers might have provided both prey and nectar resources. In 2010, cowpea and sunn hemp flowering plants provided a source of an alternate host insect's eggs for Trichogramma spp. oviposition, resulting in significantly higher parasitism of H. zea eggs in the cowpea- and sunn hemp-interplanted treatments compared to the monocrop control. Despite of differences in pest and natural enemy interactions in two field trials, our findings suggested that provisioning of an alternate host insect's eggs through flowering plants is an effective means for enhancing Trichogramma spp. and provisioning of both nectar and prey resources through flowering plants is important for enhancing predation by Orius spp. PMID:26500338

  14. Competitive release and outbreaks of non-target pests associated with transgenic Bt cotton.

    Science.gov (United States)

    Zeilinger, Adam R; Olson, Dawn M; Andow, David A

    2016-06-01

    The adoption of transgenic Bt cotton has, in some cases, led to environmental and economic benefits through reduced insecticide use. However, the distribution of these benefits and associated risks among cotton growers and cotton-growing regions has been uneven due in part to outbreaks of non-target or secondary pests, thereby requiring the continued use of synthetic insecticides. In the southeastern USA, Bt cotton adoption has resulted in increased abundance of and damage from stink bug pests, Euschistus servus and Nezara viridula (Heteroptera: Pentatomidae). While the impact of increased stink bug abundance has been well-documented, the causes have remained unclear. We hypothesize that release from competition with Bt-susceptible target pests may drive stink bug outbreaks in Bt cotton. We first examined the evidence for competitive release of stink bugs through meta-analysis of previous studies. We then experimentally tested if herbivory by Bt-susceptible Helicoverpa zea increases stink bug leaving rates and deters oviposition on non-Bt cotton. Consistent with previous studies, we found differences in leaving rates only for E servus, but we found that both species strongly avoided ovipositing on H. zea-damaged plants. Considering all available evidence, competitive release of stink bug populations in Bt cotton likely contributes to outbreaks, though the relative importance of competitive release remains an open question. Ecological risk assessments of Bt crops and other transgenic insecticidal crops would benefit from greater understanding of the ecological mechanisms underlying non-target pest outbreaks and greater attention to indirect ecological effects more broadly.

  15. Maize death acids, 9-lipoxygenase-derived cyclopente(a)nones, display activity as cytotoxic phytoalexins and transcriptional mediators.

    Science.gov (United States)

    Christensen, Shawn A; Huffaker, Alisa; Kaplan, Fatma; Sims, James; Ziemann, Sebastian; Doehlemann, Gunther; Ji, Lexiang; Schmitz, Robert J; Kolomiets, Michael V; Alborn, Hans T; Mori, Naoki; Jander, Georg; Ni, Xinzhi; Sartor, Ryan C; Byers, Sara; Abdo, Zaid; Schmelz, Eric A

    2015-09-01

    Plant damage promotes the interaction of lipoxygenases (LOXs) with fatty acids yielding 9-hydroperoxides, 13-hydroperoxides, and complex arrays of oxylipins. The action of 13-LOX on linolenic acid enables production of 12-oxo-phytodienoic acid (12-OPDA) and its downstream products, termed "jasmonates." As signals, jasmonates have related yet distinct roles in the regulation of plant resistance against insect and pathogen attack. A similar pathway involving 9-LOX activity on linolenic and linoleic acid leads to the 12-OPDA positional isomer, 10-oxo-11-phytodienoic acid (10-OPDA) and 10-oxo-11-phytoenoic acid (10-OPEA), respectively; however, physiological roles for 9-LOX cyclopentenones have remained unclear. In developing maize (Zea mays) leaves, southern leaf blight (Cochliobolus heterostrophus) infection results in dying necrotic tissue and the localized accumulation of 10-OPEA, 10-OPDA, and a series of related 14- and 12-carbon metabolites, collectively termed "death acids." 10-OPEA accumulation becomes wound inducible within fungal-infected tissues and at physiologically relevant concentrations acts as a phytoalexin by suppressing the growth of fungi and herbivores including Aspergillus flavus, Fusarium verticillioides, and Helicoverpa zea. Unlike previously established maize phytoalexins, 10-OPEA and 10-OPDA display significant phytotoxicity. Both 12-OPDA and 10-OPEA promote the transcription of defense genes encoding glutathione S transferases, cytochrome P450s, and pathogenesis-related proteins. In contrast, 10-OPEA only weakly promotes the accumulation of multiple protease inhibitor transcripts. Consistent with a role in dying tissue, 10-OPEA application promotes cysteine protease activation and cell death, which is inhibited by overexpression of the cysteine protease inhibitor maize cystatin-9. Unlike jasmonates, functions for 10-OPEA and associated death acids are consistent with specialized roles in local defense reactions. PMID:26305953

  16. Effects of bacillus thuringiensis transgenic corn on corn earworm and fall armyworm (Lepidoptera: Noctuidae) densities.

    Science.gov (United States)

    Chilcutt, Charles F; Odvody, Gary N; Correa, J Carlos; Remmers, Jeff

    2007-04-01

    We examined 17 pairs of near-isogenic hybrids of Bacillus thuringiensis (Bt) (176, Mon810, and Bt11) and non-Bt corn, Zea mays L., to examine the effects of Bt on larval densities of Helicoverpa zea (Boddie) and Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) during 2 yr. During ear formation, instar densities of H. zea and S. frugiperda were recorded for each hybrid. We found that H. zea first, second, and fifth instar densities were each affected by Mon810 and Bt11 Bt corn but not by 176 corn. Surprisingly, first and second instars were found in higher numbers on ears of Mon810 and Bt11 corn than on non-Bt corn. Densities of third and fourth instars were equal on Bt and non-Bt hybrids, whereas densities of fifth instars were lower on Bt plants. S. frugiperda larval densities were only affected during 1 yr when second, and fourth to sixth instars were lower on ears of Mon810 and Bt11 hybrids compared with their non-Bt counterparts. Two likely explanations for early instar H. zea densities being higher on Bt corn than non-Bt corn are that (1) Bt toxins delay development, creating a greater abundance of early instars that eventually die, and (2) reduced survival of H. zea to later instars on Bt corn decreased the normal asymmetric cannibalism or H. zea-S. frugiperda intraguild predation of late instars on early instars. Either explanation could explain why differences between Bt and non-Bt plants were greater for H. zea than S. frugiperda, because H. zea is more strongly affected by Bt toxins and more cannibalistic.

  17. Cross-pollination of nontransgenic corn ears with transgenic Bt corn: efficacy against lepidopteran pests and implications for resistance management.

    Science.gov (United States)

    Burkness, E C; O'Rourke, P K; Hutchison, W D

    2011-10-01

    The efficacy of nontransgenic sweet corn, Zea mays L., hybrids cross-pollinated by Bacillus thuringiensis (Bt) sweet corn hybrids expressing Cry1Ab toxin was evaluated in both field and laboratory studies in Minnesota in 2000. Non-Bt and Bt hybrids (maternal plants) were cross-pollinated with pollen from both non-Bt and Bt hybrids (paternal plants) to create four crosses. Subsequent crosses were evaluated for efficacy in the field against European corn borer, Ostrinia nubilalis (Hübner), and corn earworm, Helicoverpa zea (Boddie), and in laboratory bioassays against O. nubilalis. Field studies indicated that crosses with maternal Bt plants led to low levels of survival for both O. nubilalis and H. zea compared with the non-Bt x non-Bt cross. However, the cross between non-Bt ears and Bt pollen led to survival rates of 43 and 63% for O. nubilalis and H. zea larvae, respectively. This intermediate level of survival also was reflected in the number of kernels damaged. Laboratory bioassays for O. nubilalis, further confirmed field results with larval survival on kernels from the cross between non-Bt ears and Bt pollen reaching 60% compared with non-Bt crossed with non-Bt. These results suggest that non-Bt refuge plants, when planted in proximity to Bt plants, and cross-pollinated, can result in sublethal exposure of O. nubilalis and H. zea larvae to Bt and may undermine the high-dose/refuge resistance management strategy for corn hybrids expressing Cry1Ab.

  18. Isolation of an orally active insecticidal toxin from the venom of an Australian tarantula.

    Directory of Open Access Journals (Sweden)

    Margaret C Hardy

    Full Text Available Many insect pests have developed resistance to existing chemical insecticides and consequently there is much interest in the development of new insecticidal compounds with novel modes of action. Although spiders have deployed insecticidal toxins in their venoms for over 250 million years, there is no evolutionary selection pressure on these toxins to possess oral activity since they are injected into prey and predators via a hypodermic needle-like fang. Thus, it has been assumed that spider-venom peptides are not orally active and are therefore unlikely to be useful insecticides. Contrary to this dogma, we show that it is possible to isolate spider-venom peptides with high levels of oral insecticidal activity by directly screening for per os toxicity. Using this approach, we isolated a 34-residue orally active insecticidal peptide (OAIP-1 from venom of the Australian tarantula Selenotypus plumipes. The oral LD50 for OAIP-1 in the agronomically important cotton bollworm Helicoverpa armigera was 104.2±0.6 pmol/g, which is the highest per os activity reported to date for an insecticidal venom peptide. OAIP-1 is equipotent with synthetic pyrethroids and it acts synergistically with neonicotinoid insecticides. The three-dimensional structure of OAIP-1 determined using NMR spectroscopy revealed that the three disulfide bonds form an inhibitor cystine knot motif; this structural motif provides the peptide with a high level of biological stability that probably contributes to its oral activity. OAIP-1 is likely to be synergized by the gut-lytic activity of the Bacillus thuringiensis Cry toxin (Bt expressed in insect-resistant transgenic crops, and consequently it might be a good candidate for trait stacking with Bt.

  19. A comparison of Bt transgene, hybrid background, water stress, and insect stress effects on corn leaf and ear injury and subsequent yield.

    Science.gov (United States)

    Brewer, Michael J; Odvody, Gary N; Anderson, Darwin J; Remmers, Jeffrey C

    2014-06-01

    Experimentally manipulated water and insect stresses were applied to field-grown corn with different Bacillus thuringiensis (Bt) transgenes and no Bt transgenes, and different nontransgenic hybrid backgrounds (2011 and 2012, Corpus Christi, TX). Differences in leaf injury, ear injury, and yield were detected among experimental factors and their interactions. Under high and low water stress, injury from noctuid larvae (Lepidoptera: Noctuidae) on leaves during vegetative growth (primarily from fall armyworm, Spodoptera frugiperda J.E. Smith) and on developing ears (primarily from corn earworm, Helicoverpa zea [Boddie]) was lowest on more recent releases of Bt hybrids (newer Bt hybrids) expressing Cry1A.105+Cry2Ab2 and Cry 3Bb1, compared with earlier Bt hybrids (older Bt hybrids) expressing Cry1Ab and Cry3Bb1 and non-Bt hybrids. High water stress led to increased leaf injury under substantial fall armyworm feeding pressure in 2011 (as high as 8.7 on a 1-9 scale of increasing injury). In contrast, ear injury by corn earworm (as high as 20 cm(2) of surface area of injury) was greater in low water stress conditions. Six hybrid backgrounds did not influence leaf injury, while ear injury differences across hybrid backgrounds were detected for non-Bt and older Bt hybrid versions. While newer Bt hybrids expressing Cry1A.105+Cry2Ab2 and Cry 3Bb1 had consistent low leaf injury and high yield and low but less consistent ear injury across six hybrid backgrounds, water stress was a key factor that influenced yield. Bt transgenes played a more variable and lesser role when interacting with water stress to affect yield. These results exemplify the interplay of water and insect stress with plant injury and yield, their interactions with Bt transgenes, and the importance of these interactions in considering strategies for Bt transgene use where water stress is common. PMID:24780114

  20. Competitive release and outbreaks of non-target pests associated with transgenic Bt cotton.

    Science.gov (United States)

    Zeilinger, Adam R; Olson, Dawn M; Andow, David A

    2016-06-01

    The adoption of transgenic Bt cotton has, in some cases, led to environmental and economic benefits through reduced insecticide use. However, the distribution of these benefits and associated risks among cotton growers and cotton-growing regions has been uneven due in part to outbreaks of non-target or secondary pests, thereby requiring the continued use of synthetic insecticides. In the southeastern USA, Bt cotton adoption has resulted in increased abundance of and damage from stink bug pests, Euschistus servus and Nezara viridula (Heteroptera: Pentatomidae). While the impact of increased stink bug abundance has been well-documented, the causes have remained unclear. We hypothesize that release from competition with Bt-susceptible target pests may drive stink bug outbreaks in Bt cotton. We first examined the evidence for competitive release of stink bugs through meta-analysis of previous studies. We then experimentally tested if herbivory by Bt-susceptible Helicoverpa zea increases stink bug leaving rates and deters oviposition on non-Bt cotton. Consistent with previous studies, we found differences in leaving rates only for E servus, but we found that both species strongly avoided ovipositing on H. zea-damaged plants. Considering all available evidence, competitive release of stink bug populations in Bt cotton likely contributes to outbreaks, though the relative importance of competitive release remains an open question. Ecological risk assessments of Bt crops and other transgenic insecticidal crops would benefit from greater understanding of the ecological mechanisms underlying non-target pest outbreaks and greater attention to indirect ecological effects more broadly. PMID:27509747

  1. Manejo de lepidópteros-praga na cultura do milho com o evento Bt piramidado Cry1A.105 e Cry2Ab2

    Directory of Open Access Journals (Sweden)

    José Magid Waquil

    2013-12-01

    Full Text Available O objetivo deste trabalho foi avaliar a eficácia do evento piramidado (MON 89034, que expressa as proteínas Cry1A.105 e Cry2Ab2, no controle dos principais lepidópteros-praga da cultura do milho no Brasil, Spodoptera frugiperda, Helicoverpa spp. e Diatraea saccharalis. Os ensaios foram conduzidos em quatro regiões do país, com o híbrido DKB 390, submetido a seis tratamentos: híbrido com o evento piramidado, híbrido com o evento que expressa apenas a proteína Cry1A(b (MON 810 e híbrido convencional (não Bt, todos com e sem manejo integrado de S. frugiperda. Para o evento piramidado, não foi necessário o controle químico em nenhum dos locais avaliados. Diferenças significativas foram observadas entre os tratamentos quanto aos danos e à presença de lagartas. Em geral, essas variáveis foram mais baixas no híbrido com o evento piramidado e mais altas no híbrido convencional, sem controle químico. Sob alta infestação, o controle químico reduziu os danos causados por S. frugiperda e D. saccharalis, tanto no evento que expressa apenas uma proteína, como no híbrido convencional. Com base nos danos causados pelos insetos, o evento piramidado Cry1A.105 e Cry2Ab2 é eficiente no controle dos principais lepidópteros-pragas do milho no Brasil.

  2. Pheromone Lure and Trap Color Affects Bycatch in Agricultural Landscapes of Utah.

    Science.gov (United States)

    Spears, Lori R; Looney, Chris; Ikerd, Harold; Koch, Jonathan B; Griswold, Terry; Strange, James P; Ramirez, Ricardo A

    2016-08-01

    Aerial traps, using combinations of color and attractive lures, are a critical tool for detecting and managing insect pest populations. Yet, despite improvements in trap efficacy, collection of nontarget species ("bycatch") plagues many insect pest surveys. Bycatch can influence survey effectiveness by reducing the available space for target species and increasing trap screening time, especially in areas where thousands of insects are captured as bycatch in a given season. Additionally, bycatch may negatively impact local nontarget insect populations, including beneficial predators and pollinators. Here, we tested the effect of pheromone lures on bycatch rates of Coccinellidae (Coleoptera), Apoidea (Hymenoptera), and nontarget Lepidoptera. Multicolored (primarily yellow and white) bucket traps containing a pheromone lure for capturing one of three survey target species, Spodoptera litura (F.), S. littoralis (Boisduval), or Helicoverpa armigera (Hübner), were placed in alfalfa and corn fields, and compared to multicolored traps without a pheromone lure. All-green traps with and without H. armigera lures were employed in a parallel study investigating the effect of lure and trap color on bycatch. Over 2,600 Coccinellidae representing seven species, nearly 6,400 bees in 57 species, and >9,000 nontarget moths in 17 genera were captured across 180 traps and seven temporal sampling events. Significant effects of lure and color were observed for multiple taxa. In general, nontarget insects were attracted to the H. armigera lure and multicolored trap, but further studies of trap color and pheromone lure specificity are needed to better understand these interactions and to minimize nontarget captures. PMID:27412193

  3. Re-evaluation of the PBAN receptor (PBANR molecule: characterization of PBANR variants expressed in the pheromone glands of moths

    Directory of Open Access Journals (Sweden)

    Jae Min Lee

    2012-01-01

    Full Text Available Sex pheromone production in most moths is initiated following pheromone biosynthesis activating neuropeptide receptor (PBANR activation. PBANR was initially cloned from pheromone glands (PGs of Helicoverpa zea and Bombyx mori. The B. mori PBANR is characterized by a relatively long C-terminus that is essential for ligand-induced internalization, whereas the H. zea PBANR has a shorter C-terminus that lacks features present in the B. mori PBANR critical for internalization. Multiple PBANRs have been reported to be concurrently expressed in the larval CNS of Heliothis virescens. In the current study, we sought to examine the prevalence of multiple PBANRs in the PGs of three moths and to ascertain their potential functional relevance. Multiple PBANR variants (As, A, B, and C were cloned from the PGs of all species examined with PBANR-C the most highly expressed. Alternative splicing of the C-terminal coding sequence of the PBAN gene gives rise to the variants, which are distinguishable only by the length and composition of their respective C-terminal tails. Transient expression of fluorescent PBANR chimeras in insect cells revealed that PBANR-B and PBANR-C localized exclusively to the cell surface while PBANR-As and PBANR-A exhibited varying degrees of cytosolic localization. Similarly, only the PBANR-B and PBANR-C variants underwent ligand-induced internalization. Taken together, our results suggest that PBANR-C is the principal receptor molecule involved in PBAN signaling regardless of moth species. The high GC content of the C-terminal coding sequence in the B and C variants, which makes amplification using conventional polymerases difficult, likely accounts for previous preferential amplification of PBANR-A like receptors from other species.

  4. Resistance to Bacillus thuringiensis Mediated by an ABC Transporter Mutation Increases Susceptibility to Toxins from Other Bacteria in an Invasive Insect

    Science.gov (United States)

    Zhang, Dandan; Gong, Lingling; He, Fei; Soberón, Mario; Bravo, Alejandra; Tabashnik, Bruce E.; Wu, Kongming

    2016-01-01

    Evolution of pest resistance reduces the efficacy of insecticidal proteins from the gram-positive bacterium Bacillus thuringiensis (Bt) used widely in sprays and transgenic crops. Recent efforts to delay pest adaptation to Bt crops focus primarily on combinations of two or more Bt toxins that kill the same pest, but this approach is often compromised because resistance to one Bt toxin causes cross-resistance to others. Thus, integration of Bt toxins with alternative controls that do not exhibit such cross-resistance is urgently needed. The ideal scenario of negative cross-resistance, where selection for resistance to a Bt toxin increases susceptibility to alternative controls, has been elusive. Here we discovered that selection of the global crop pest, Helicoverpa armigera, for >1000-fold resistance to Bt toxin Cry1Ac increased susceptibility to abamectin and spineotram, insecticides derived from the soil bacteria Streptomyces avermitilis and Saccharopolyspora spinosa, respectively. Resistance to Cry1Ac did not affect susceptibility to the cyclodiene, organophospate, or pyrethroid insecticides tested. Whereas previous work demonstrated that the resistance to Cry1Ac in the strain analyzed here is conferred by a mutation disrupting an ATP-binding cassette protein named ABCC2, the new results show that increased susceptibility to abamectin is genetically linked with the same mutation. Moreover, RNAi silencing of HaABCC2 not only decreased susceptibility to Cry1Ac, it also increased susceptibility to abamectin. The mutation disrupting ABCC2 reduced removal of abamectin in live larvae and in transfected Hi5 cells. The results imply that negative cross-resistance occurs because the wild type ABCC2 protein plays a key role in conferring susceptibility to Cry1Ac and in decreasing susceptibility to abamectin. The negative cross-resistance between a Bt toxin and other bacterial insecticides reported here may facilitate more sustainable pest control. PMID:26872031

  5. How does atmospheric elevated CO2 affect crop pests and their natural enemies? Case histories from China

    Institute of Scientific and Technical Information of China (English)

    Yu-Cheng Sun; Jin Yin; Fa-Jun Chen; Gang Wu; Feng Ge

    2011-01-01

    Global atmospheric CO2 concentrations have risen rapidly since the Industrial Revolution and are considered as a primary factor in climate change.The effects of elevated CO2 on herbivore insects were found to be primarily through the CO2-induced changes occurring in their host plants,which then possibly affect the intensity and frequency of pest outbreaks on crops.This paper reviews several ongoing research models using primary pests of crops (cotton bollworm,whitefly,aphids) and their natural enemies (ladybeetles,parasitoids) in China to examine insect responses to elevated CO2.It is generally indicated that elevated CO2 prolonged the development of cotton bollworm,Helicoverpa armigera,a chewing insect,by decreasing the foliar nitrogen of host plants.In contrast,the phloemsucking aphid and whitefly insects had species-specific responses to elevated CO2 because of complex interactions that occur in the phloem sieve elements of plants.Some aphid species,such as cotton aphid,Aphis gossypii and wheat aphid,Sitobion avenae,were considered to represent the only feeding guild to respond positively to elevated CO2 conditions.Although whitefly,Bemisia tabaci,a major vector of Tomato yellow leaf curl virus,had neutral response to elevated CO2,the plants became less vulnerable to the virus infection under elevated CO2.The predator and parasitoid response to elevated CO2 were frequently idiosyncratic.These documents from Chinese scientists suggested that elevated CO2 initially affects the crop plant and then cascades to a higher trophic level through the food chain to encompass herbivores (pests),their natural enemies,pathogens and underground nematodes,which disrupt the natural balance observed previously in agricultural ecosystems.

  6. Intraguild Competition of Three Noctuid Maize Pests.

    Science.gov (United States)

    Bentivenha, J P F; Baldin, E L L; Hunt, T E; Paula-Moraes, S V; Blankenship, E E

    2016-08-01

    The western bean cutworm Striacosta albicosta (Smith), the fall armyworm Spodoptera frugiperda (J. E. Smith), and the corn earworm Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) are among the major lepidopteran pests of maize in the United States, belonging to the same guild and injuring the reproductive tissues of this crop. Here, intraguild competition of these lepidopterans on non-Bt maize was evaluated through survival analysis of each species under laboratory and field conditions. Competition scenarios were carried out in arenas containing maize silk or ear tissue, using larvae on different stadium of development. Fitness cost competition studies were conducted to examine the influence of intraguild competition and cannibalism and predation rates on larval development. The survival of S. albicosta competing with the other species was significantly lower than in intraspecific competition, even when the larvae were more developed than the competitor. For S. frugiperda, survival remained high in the different competition scenarios, except when competing in a smaller stadium with H. zea Larvae of H. zea had a high rate of cannibalism, higher survival when competing against S. albicosta than S. frugiperda, and reduced survival when the H. zea larvae were at the same development stadium or smaller than the competitors. Based on fitness cost results, the absence of a competitor for the feeding source may confer an advantage to the larval development of S. frugiperda and H. zea Our data suggest that S. frugiperda has a competitive advantage against the other species, while S. albicosta has the disadvantage in the intraguild competition on non-Bt maize. PMID:27330146

  7. High Expression of Cry1Ac Protein in Cotton (Gossypium hirsutum) by Combining Independent Transgenic Events that Target the Protein to Cytoplasm and Plastids

    Science.gov (United States)

    Singh, Amarjeet Kumar; Paritosh, Kumar; Kant, Uma; Burma, Pradeep Kumar; Pental, Deepak

    2016-01-01

    Transgenic cotton was developed using two constructs containing a truncated and codon-modified cry1Ac gene (1,848 bp), which was originally characterized from Bacillus thuringiensis subspecies kurstaki strain HD73 that encodes a toxin highly effective against many lepidopteran pests. In Construct I, the cry1Ac gene was cloned under FMVde, a strong constitutively expressing promoter, to express the encoded protein in the cytoplasm. In Construct II, the encoded protein was directed to the plastids using a transit peptide taken from the cotton rbcSIb gene. Genetic transformation experiments with Construct I resulted in a single copy insertion event in which the Cry1Ac protein expression level was 2–2.5 times greater than in the Bacillus thuringiensis cotton event Mon 531, which is currently used in varieties and hybrids grown extensively in India and elsewhere. Another high expression event was selected from transgenics developed with Construct II. The Cry protein expression resulting from this event was observed only in the green plant parts. No transgenic protein expression was observed in the non-green parts, including roots, seeds and non-green floral tissues. Thus, leucoplasts may lack the mechanism to allow entry of a protein tagged with the transit peptide from a protein that is only synthesized in tissues containing mature plastids. Combining the two events through sexual crossing led to near additive levels of the toxin at 4–5 times the level currently used in the field. The two high expression events and their combination will allow for effective resistance management against lepidopteran insect pests, particularly Helicoverpa armigera, using a high dosage strategy. PMID:27391960

  8. Complexity and variability of gut commensal microbiota in polyphagous lepidopteran larvae.

    Directory of Open Access Journals (Sweden)

    Xiaoshu Tang

    Full Text Available BACKGROUND: The gut of most insects harbours nonpathogenic microorganisms. Recent work suggests that gut microbiota not only provide nutrients, but also involve in the development and maintenance of the host immune system. However, the complexity, dynamics and types of interactions between the insect hosts and their gut microbiota are far from being well understood. METHODS/PRINCIPAL FINDINGS: To determine the composition of the gut microbiota of two lepidopteran pests, Spodoptera littoralis and Helicoverpa armigera, we applied cultivation-independent techniques based on 16S rRNA gene sequencing and microarray. The two insect species were very similar regarding high abundant bacterial families. Different bacteria colonize different niches within the gut. A core community, consisting of Enterococci, Lactobacilli, Clostridia, etc. was revealed in the insect larvae. These bacteria are constantly present in the digestion tract at relatively high frequency despite that developmental stage and diet had a great impact on shaping the bacterial communities. Some low-abundant species might become dominant upon loading external disturbances; the core community, however, did not change significantly. Clearly the insect gut selects for particular bacterial phylotypes. CONCLUSIONS: Because of their importance as agricultural pests, phytophagous Lepidopterans are widely used as experimental models in ecological and physiological studies. Our results demonstrated that a core microbial community exists in the insect gut, which may contribute to the host physiology. Host physiology and food, nevertheless, significantly influence some fringe bacterial species in the gut. The gut microbiota might also serve as a reservoir of microorganisms for ever-changing environments. Understanding these interactions might pave the way for developing novel pest control strategies.

  9. Impact of applying edible oils to silk channels on ear pests of sweet corn.

    Science.gov (United States)

    Ni, Xinzhi; Sparks, Alton N; Riley, David G; Li, Xianchun

    2011-06-01

    The impact of applying edible oils to corn silks on ear-feeding insects in sweet corn, Zea mays L., production was evaluated in 2006 and 2007. Six edible oils used in this experiment were canola, corn, olive, peanut, sesame, and soybean. Water and two commercial insecticidal oils (Neemix neem oil and nC21 Sunspray Ultrafine, a horticultural mineral oil) were used as the controls for the experiment. Six parameters evaluated in this experiment were corn earworm [Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae)] damage rating, the number of sap beetle [Carpophilus spp. (Coleoptera: Nitidulidae)] adults and larvae, the number of corn silk fly (or picture-winged fly) (Diptera: Ulidiidae) larvae, common smut [Ustilago maydis (D.C.) Corda] infection rate, and corn husk coverage. Among the two control treatments, neem oil reduced corn earworm damage at both pre- and postpollination applications in 2006, but not in 2007, whereas the mineral oil applied at postpollination treatments reduced corn earworm damage in both years. The mineral oil also reduced the number of sap beetle adults, whereas the neem oil applied at postpollination attracted the most sap beetle adults in 2007. Among the six edible oil treatments, the corn and sesame oils applied at postpollination reduced corn earworm damage only in 2007. The application of the peanut oil at postpollination attracted more sap beetle adults in 2006, and more sap beetle larvae in 2007. Olive and neem oils significantly reduced husk coverage compared with the water control in both years. The mineral oil application consistently increased smut infection rate in both 2006 and 2007. Ramifications of using oil treatments in ear pest management also are discussed.

  10. Degradation of the S. frugiperda peritrophic matrix by an inducible maize cysteine protease.

    Science.gov (United States)

    Mohan, S; Ma, P W K; Pechan, T; Bassford, E R; Williams, W P; Luthe, D S

    2006-01-01

    A unique 33-kDa cysteine protease (Mir1-CP) rapidly accumulates at the feeding site in the whorls of maize (Zea mays L.) lines that are resistant to herbivory by Spodoptera frugiperda and other lepidopteran species. When larvae were reared on resistant plants, larval growth was reduced due to impaired nutrient utilization. Scanning electron microscopy (SEM) indicated that the peritrophic matrix (PM) was damaged when larvae fed on resistant plants or transgenic maize callus expressing Mir1-CP. To directly determine the effects of Mir1-CP on the PM in vitro, dissected PMs were treated with purified, recombinant Mir1-CP and the movement of Blue Dextran 2000 across the PM was measured. Mir1-CP completely permeabilized the PM and the time required to reach full permeability was inversely proportional to the concentration of Mir1-CP. Inclusion of E64, a specific cysteine protease inhibitor prevented the damage. The lumen side of the PM was more vulnerable to Mir1-CP attack than the epithelial side. Mir1-CP damaged the PM at pH values as high as 8.5 and more actively permeabilized the PM than equivalent concentrations of the cysteine proteases papain, bromelain and ficin. The effect of Mir1-CP on the PMs of Helicoverpa zea, Danaus plexippus, Ostrinia nubilalis, Periplaneta americana and Tenebrio molitor also was tested, but the greatest effect was on the S. frugiperda PM. These results demonstrate that the insect-inducible Mir1-CP directly damages the PM in vitro and is critical to insect defense in maize.

  11. High Expression of Cry1Ac Protein in Cotton (Gossypium hirsutum by Combining Independent Transgenic Events that Target the Protein to Cytoplasm and Plastids.

    Directory of Open Access Journals (Sweden)

    Amarjeet Kumar Singh

    Full Text Available Transgenic cotton was developed using two constructs containing a truncated and codon-modified cry1Ac gene (1,848 bp, which was originally characterized from Bacillus thuringiensis subspecies kurstaki strain HD73 that encodes a toxin highly effective against many lepidopteran pests. In Construct I, the cry1Ac gene was cloned under FMVde, a strong constitutively expressing promoter, to express the encoded protein in the cytoplasm. In Construct II, the encoded protein was directed to the plastids using a transit peptide taken from the cotton rbcSIb gene. Genetic transformation experiments with Construct I resulted in a single copy insertion event in which the Cry1Ac protein expression level was 2-2.5 times greater than in the Bacillus thuringiensis cotton event Mon 531, which is currently used in varieties and hybrids grown extensively in India and elsewhere. Another high expression event was selected from transgenics developed with Construct II. The Cry protein expression resulting from this event was observed only in the green plant parts. No transgenic protein expression was observed in the non-green parts, including roots, seeds and non-green floral tissues. Thus, leucoplasts may lack the mechanism to allow entry of a protein tagged with the transit peptide from a protein that is only synthesized in tissues containing mature plastids. Combining the two events through sexual crossing led to near additive levels of the toxin at 4-5 times the level currently used in the field. The two high expression events and their combination will allow for effective resistance management against lepidopteran insect pests, particularly Helicoverpa armigera, using a high dosage strategy.

  12. Survival of Corn Earworm (Lepidoptera: Noctuidae) on Bt Maize and Cross-Pollinated Refuge Ears From Seed Blends.

    Science.gov (United States)

    Crespo, André Luiz Barreto; Alves, Analiza Piovesan; Wang, Yiwei; Hong, Bonnie; Flexner, John Lindsey; Catchot, Angus; Buntin, David; Cook, Donald

    2016-02-01

    Refuge is mandated in the United States where genetically modified maize (Zea mays L.) expressing insecticidal proteins derived from Bacillus thuringiensis Berliner (Bt) are cultivated. Currently, refuge is deployed in different ways including blocks, field strips, or seed blends containing Bt and non-Bt maize. Seed blends provide practical advantages for refuge implementation. However, concerns related to the movement of insect larvae, potential differential survival of heterozygous resistant larvae, reduction in insect production, and cross-pollination of ears resulting in sublethal selection, have delayed seed blend use for Lepidoptera in the southern United States, where maize plantings are used as refuge for Helicoverpa zea (Boddie). In this study, we evaluated the relative survival of H. zea in Bt events and in seed blends compared with pure stand refuge and the relative survival of H. zea on the individual components of the pyramid 1507xMON810xMIR162. The results showed variation on the production of H. zea in refuge plants from seed blends compared with pure stand refuge plants. The relative survival of H. zea on the events 1507, MON810, MIR162, and 1507xMON810xMIR162 ranked similarly across the three locations tested. These results can be used in computer simulation modeling efforts to evaluate the feasibility of seed blends as a refuge deployment strategy with the pyramid 1507xMON810xMIR162. Because the reduction on survival of H. zea due to blending was variable, a sensitivity analysis that includes all possible scenarios of reduction in survival should be considered. PMID:26357846

  13. Increased frequency of pink bollworm resistance to Bt toxin Cry1Ac in China.

    Directory of Open Access Journals (Sweden)

    Peng Wan

    Full Text Available Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt kill some key insect pests, but evolution of resistance by pests can reduce their efficacy. The main approach for delaying pest adaptation to Bt crops uses non-Bt host plants as "refuges" to increase survival of susceptible pests. To delay evolution of pest resistance to transgenic cotton producing Bt toxin Cry1Ac, the United States and some other countries have required refuges of non-Bt cotton, while farmers in China have relied on "natural" refuges of non-Bt host plants other than cotton. The "natural" refuge strategy focuses on cotton bollworm (Helicoverpa armigera, the primary target of Bt cotton in China that attacks many crops, but it does not apply to another major pest, pink bollworm (Pectinophora gossypiella, which feeds almost entirely on cotton in China. Here we report data showing field-evolved resistance to Cry1Ac by pink bollworm in the Yangtze River Valley of China. Laboratory bioassay data from 51 field-derived strains show that the susceptibility to Cry1Ac was significantly lower during 2008 to 2010 than 2005 to 2007. The percentage of field populations yielding one or more survivors at a diagnostic concentration of Cry1Ac increased from 0% in 2005-2007 to 56% in 2008-2010. However, the median survival at the diagnostic concentration was only 1.6% from 2008 to 2010 and failure of Bt cotton to control pink bollworm has not been reported in China. The early detection of resistance reported here may promote proactive countermeasures, such as a switch to transgenic cotton producing toxins distinct from Cry1A toxins, increased planting of non-Bt cotton, and integration of other management tactics together with Bt cotton.

  14. 使用SSI模型描述昆虫温发育速率的SAS程序

    Institute of Scientific and Technical Information of China (English)

    时培建; 戈峰

    2014-01-01

    Sharpe-Schoolfield-Ikemoto(SSI)模型是用来描述温度对昆虫发育速率影响的一个重要数学方程,它既能够很好地拟合温发育速率的数据,又能提供若干个重要温参数,特别是内禀最适发育温度(TΦ)。此温度反映了昆虫生存的最佳温环境。然而,由于SSI模型的参数过多,结构显得较为复杂,给实际的数据拟合带来了困难。一个基于R平台的软件包已经被开发出来,专门用于执行SSI模型的参数拟合。但目前由于国内许多研究者青睐于使用SAS统计软件,所以本文提供了一个基于SAS统计软件的程序,用以快速拟合SSI模型的参数。通过拟合棉铃虫Helicoverpa armigera Hübner蛹期的温发育速率数据,发现此SAS程序具有很好的拟合效果,同时进一步证明了SSI模型对描述温度对昆虫发育速率影响的有效性。

  15. Transmission of Different Nucleopolyhedroviruses by Two Ectoparasitoids – Bracon hebetor Say (Hymenoptera: Braconidae and Euplectrus plathypenae (Howard (Hymenoptera: Eulophidae

    Directory of Open Access Journals (Sweden)

    Emanouela E. Stoianova

    2010-01-01

    Full Text Available The transmission of nucleopolyhedroviruses (NPVs of Autographa gamma (AgNPV,Mamestra brassicae (MbNPV, Lacanobia oleraceae (LoNPV, Helicoverpa armigera (HaNPVand Xantia c-nigrum (XnNPV to their relevant larvae by the ectoparasitoid Bracon hebetorand the transmission of the multiple-enveloped NPVs of Spodoptera exigua (SeMNPV andSpodoptera frugiperda (SfMNPV by the ectoparasitoid Euplectrus plathypenae was examined.Two methods of contamination of the both parasitoids (exposure to infected hostsand total body surface and two subsequent transmissions of the viruses by Bracon hebetorto healthy hosts were tested. The results showed that both parasitoids were capable tobe mechanical vectors of the tested NPVs. Every Bracon hebetor female was able to transmitsubsequently twice the virus in 27% to 52.2% of the five Noctuidae species by preliminaryexposing to infected larvae. The second method of contamination (applying virus suspensionto the total body surface of the parasitoid was also efficient causing virus infection inbetween 29.4% and 54.15% of the larvae.The parasitoid E. plathypenae transmited the virus from infected to noninfected larvaein 20% and 25.57% of the S. frugiperda and S. exigua larvae, and 6.43% and 11.10%, respectivelyof them died from the virus infection. The same observation was established by thesecond method of contamination – respectively 33.33% and 40% infection and between13.23% and 16.67% mortality. The mortality of all tested larvae exposed to virus contaminated parasitoids was higherwhen the parasitoid entire body surface had been artificially contaminated with the virusthan when the parasitoid itself was previously allowed to oviposit the larvae.

  16. Immunolocalization of odorant-binding proteins in noctuid moths (Insecta, Lepidoptera).

    Science.gov (United States)

    Zhang, S; Maida, R; Steinbrecht, R A

    2001-09-01

    Odorant-binding proteins were studied in the noctuid moths Agrotis segetum, Autographa gamma, Helicoverpa armigera, Heliothis virescens and Spodoptera littoralis using antisera raised against the pheromone-binding protein (PBP) and general odorant-binding protein 2 (GOBP2) of Antheraea polyphemus (Saturniidae). Proteins immunoreacting with these antisera were only found on the antennae and PBP and GOBP2 could be identified on western blots of males and females of all five species. PBPs were predominantly localized in sensilla trichodea and GOBP2 in sensilla basiconica, in good correlation with the stimulus specificity of the receptor cells in these sensilla. In H. armigera and H. virescens the majority of the s. trichodea immunoreacted with the antiserum against PBP of A. polyphemus; in A. segetum, A. gamma and S. littoralis, on the other hand, a high percentage of s. trichodea remained unlabelled. Probably, the PBP expressed in these sensilla is so different that it does not immunoreact with the antiserum used. Such a protein was found by native PAGE of antennal extracts of A. segetum and S. littoralis. These data correlate with the fact that the two heliothine species use pheromones with the same alkyl chain length as A. polyphemus, while the other three species use pheromones with shorter chains. In H. armigera, H. virescens, A. gamma and S. littoralis female antennae were also immunolabelled and a large number of PBP-expressing s. trichodea was consistently found. In S.littoralis this fits with the electrophysiologically recorded high pheromone sensitivity of female s. trichodea, whereas in females of H. armigera and H. virescens no or only weak responses to pheromone stimulation have been reported. Therefore, PBP expression in a sensillum does not necessarily imply pheromone sensitivity of its receptor cells. PMID:11555483

  17. Isolation of an orally active insecticidal toxin from the venom of an Australian tarantula.

    Science.gov (United States)

    Hardy, Margaret C; Daly, Norelle L; Mobli, Mehdi; Morales, Rodrigo A V; King, Glenn F

    2013-01-01

    Many insect pests have developed resistance to existing chemical insecticides and consequently there is much interest in the development of new insecticidal compounds with novel modes of action. Although spiders have deployed insecticidal toxins in their venoms for over 250 million years, there is no evolutionary selection pressure on these toxins to possess oral activity since they are injected into prey and predators via a hypodermic needle-like fang. Thus, it has been assumed that spider-venom peptides are not orally active and are therefore unlikely to be useful insecticides. Contrary to this dogma, we show that it is possible to isolate spider-venom peptides with high levels of oral insecticidal activity by directly screening for per os toxicity. Using this approach, we isolated a 34-residue orally active insecticidal peptide (OAIP-1) from venom of the Australian tarantula Selenotypus plumipes. The oral LD50 for OAIP-1 in the agronomically important cotton bollworm Helicoverpa armigera was 104.2±0.6 pmol/g, which is the highest per os activity reported to date for an insecticidal venom peptide. OAIP-1 is equipotent with synthetic pyrethroids and it acts synergistically with neonicotinoid insecticides. The three-dimensional structure of OAIP-1 determined using NMR spectroscopy revealed that the three disulfide bonds form an inhibitor cystine knot motif; this structural motif provides the peptide with a high level of biological stability that probably contributes to its oral activity. OAIP-1 is likely to be synergized by the gut-lytic activity of the Bacillus thuringiensis Cry toxin (Bt) expressed in insect-resistant transgenic crops, and consequently it might be a good candidate for trait stacking with Bt. PMID:24039872

  18. Diet micronutrient balance matters: How the ratio of dietary sterols/steroids affects development, growth and reproduction in two lepidopteran insects.

    Science.gov (United States)

    Jing, Xiangfeng; Grebenok, Robert J; Behmer, Spencer T

    2014-08-01

    Insects lack the ability to synthesize sterols de novo so they acquire this essential nutrient from their food. Cholesterol is the dominant sterol found in most insects, but in plant vegetative tissue it makes up only a small fraction of the total sterol profile. Instead, plants mostly contain phytosterols; plant-feeding insects generate the majority of their cholesterol by metabolizing phytosterols. However, not all phytosterols are readily converted to cholesterol, and some are even deleterious when ingested above a threshold level. In a recent study we showed that caterpillars reared on tobacco accumulating novel sterols/steroids exhibited reduced performance, even when suitable sterols were present. In the current study we examined how the dominant sterols (cholesterol and stigmasterol) and steroids (cholestanol and cholestanone) typical of the modified tobacco plants affected two insect herbivores (Heliothis virescens and Helicoverpa zea). The sterols/steroids were incorporated into synthetic diets singly, as well as in various combinations, ratios and amounts. For each insect species, a range of performance values was recorded for two generations, with the eggs from the 1st-generation adults as the source of neonates for the 2nd-generation. Performance on the novel steroids (cholestanol and cholestanone) was extremely poor compared to suitable sterols (cholesterol and stigmasterol). Additionally, performance tended to decrease as the ratio of the novel dietary steroids increased. We discuss how the balance of different dietary sterols/steroids affected our two caterpillar species, relate this back to recent studies on sterol/steroid metabolism in these two species, and consider the potential application of sterol/steroid modification in crops.

  19. Assessing the potential for interaction between the insecticidal activity of two genetically engineered cotton events combined by conventional breeding: An example with COT102 × MON 15985.

    Science.gov (United States)

    Levine, Steven L; Mueller, Geoffrey M; Uffman, Joshua P

    2016-08-01

    Bollgard(®) III was developed by combining cotton events COT102 and MON 15985 through conventional breeding to improve efficacy against lepidopteran feeding damage. COT102 produces the Vip3Aa19 protein and MON 15985 produces the Cry1Ac and Cry2Ab2 proteins. COT102 × MON 15985 has also been bred with Roundup Ready Flex(®) cotton (MON 88913) that confers glyphosate tolerance. This study evaluated the activity of COT102 and MON 15985 and the combined activity of COT102 and MON 15985 against the cotton bollworm (CBW, Helicoverpa zea). COT102, MON 15985, COT102 × MON 15985 and COT102 × MON 15985 × MON 88913 have comparable Vip3Aa19 and/or Cry1Ac, Cry2Ab2 protein expression levels as determined by enzyme-linked immunosorbent assay. CBW demonstrated concentration-dependent growth inhibition after 7-days of feeding on lyophilized leaf tissue derived from COT102, MON 15985, COT102 × MON 15985 and COT102 × MON 15985 × MON 88913 incorporated into an artificial diet. Observed EC50 values for COT102 × MON 15985 and COT102 × MON 15985 × MON 88913 were comparable (≤4% deviation) with the predicted EC50 value under the assumption of additivity using the combined activity of COT102 and MON 15985. No interaction in biological activity between COT102 and MON 15985 is consistent with results from competition and ligand blotting assays that demonstrated that Vip3Aa does not inhibit the binding of either Cry1Ac or Cry2Ab2 and vice versa. The results from this study demonstrate that the activity of COT102 × MON 15985 against CBW is consistent with predictions of additivity. PMID:27155596

  20. Spatial Patterns of Aflatoxin Levels in Relation to Ear-Feeding Insect Damage in Pre-Harvest Corn

    Directory of Open Access Journals (Sweden)

    Alisa Huffaker

    2011-07-01

    Full Text Available Key impediments to increased corn yield and quality in the southeastern US coastal plain region are damage by ear-feeding insects and aflatoxin contamination caused by infection of Aspergillus flavus. Key ear-feeding insects are corn earworm, Helicoverpa zea, fall armyworm, Spodoptera frugiperda, maize weevil, Sitophilus zeamais, and brown stink bug, Euschistus servus. In 2006 and 2007, aflatoxin contamination and insect damage were sampled before harvest in three 0.4-hectare corn fields using a grid sampling method. The feeding damage by each of ear/kernel-feeding insects (i.e., corn earworm/fall armyworm damage on the silk/cob, and discoloration of corn kernels by stink bugs, and maize weevil population were assessed at each grid point with five ears. The spatial distribution pattern of aflatoxin contamination was also assessed using the corn samples collected at each sampling point. Aflatoxin level was correlated to the number of maize weevils and stink bug-discolored kernels, but not closely correlated to either husk coverage or corn earworm damage. Contour maps of the maize weevil populations, stink bug-damaged kernels, and aflatoxin levels exhibited an aggregated distribution pattern with a strong edge effect on all three parameters. The separation of silk- and cob-feeding insects from kernel-feeding insects, as well as chewing (i.e., the corn earworm and maize weevil and piercing-sucking insects (i.e., the stink bugs and their damage in relation to aflatoxin accumulation is economically important. Both theoretic and applied ramifications of this study were discussed by proposing a hypothesis on the underlying mechanisms of the aggregated distribution patterns and strong edge effect of insect damage and aflatoxin contamination, and by discussing possible management tactics for aflatoxin reduction by proper management of kernel-feeding insects. Future directions on basic and applied research related to aflatoxin contamination are also

  1. High Expression of Cry1Ac Protein in Cotton (Gossypium hirsutum) by Combining Independent Transgenic Events that Target the Protein to Cytoplasm and Plastids.

    Science.gov (United States)

    Singh, Amarjeet Kumar; Paritosh, Kumar; Kant, Uma; Burma, Pradeep Kumar; Pental, Deepak

    2016-01-01

    Transgenic cotton was developed using two constructs containing a truncated and codon-modified cry1Ac gene (1,848 bp), which was originally characterized from Bacillus thuringiensis subspecies kurstaki strain HD73 that encodes a toxin highly effective against many lepidopteran pests. In Construct I, the cry1Ac gene was cloned under FMVde, a strong constitutively expressing promoter, to express the encoded protein in the cytoplasm. In Construct II, the encoded protein was directed to the plastids using a transit peptide taken from the cotton rbcSIb gene. Genetic transformation experiments with Construct I resulted in a single copy insertion event in which the Cry1Ac protein expression level was 2-2.5 times greater than in the Bacillus thuringiensis cotton event Mon 531, which is currently used in varieties and hybrids grown extensively in India and elsewhere. Another high expression event was selected from transgenics developed with Construct II. The Cry protein expression resulting from this event was observed only in the green plant parts. No transgenic protein expression was observed in the non-green parts, including roots, seeds and non-green floral tissues. Thus, leucoplasts may lack the mechanism to allow entry of a protein tagged with the transit peptide from a protein that is only synthesized in tissues containing mature plastids. Combining the two events through sexual crossing led to near additive levels of the toxin at 4-5 times the level currently used in the field. The two high expression events and their combination will allow for effective resistance management against lepidopteran insect pests, particularly Helicoverpa armigera, using a high dosage strategy. PMID:27391960

  2. Application Effects of Green Prevention and Control Technology of Solar Insecticidal Lamp and Yellow Template in Tobacco Production%太阳能杀虫灯和诱虫黄板绿色防控技术在烟草生产上的应用效果

    Institute of Scientific and Technical Information of China (English)

    董宁禹; 刘占卿; 赵世民; 刘欢欢; 王枫; 刘涛; 马玉欣; 蒋士君

    2015-01-01

    为对烟草病虫害绿色防控技术中太阳能杀虫灯及诱虫黄板的推广应用提供理论指导,于2014年在汝阳县开展了大面积示范试验,研究其杀虫防病效果。结果表明,太阳能杀虫灯布控42 d能诱杀鳞翅目、鞘翅目、直翅目等多种害虫,并且以鳞翅目和鞘翅目为主,各占诱杀害虫总量的43.47%和51.11%;单灯共计诱杀害虫4558头/台,日均诱杀害虫109头/(台·d),但对天敌昆虫危害小,单灯共计诱杀天敌昆虫16头/台,益害比为1∶284.88;田间成虫量调查结果显示,灯控区烟青虫和斜纹夜蛾的成虫量较无灯区分别下降了57.14%、62.50%。诱虫黄板使用30 d,单张单面黄板共计诱蚜6633头,日均诱蚜221.10头/d,30 d有翅蚜虫口减退率和病毒病防效分别达73.28%和68.78%。说明太阳能杀虫灯和诱虫黄板绿色防控技术联用能有效防治烟田主要病虫害,适合在烟草生产中推广应用。%In order to provide theoretical guidance for widespread use of the green prevention and control technology of solar insecticidal lamp and yellow template in tobacco production, the large area demonstration trials were developed to study their control effects on pests and diseases in Ruyang county in 2014. The results showed that the solar insecticidal lamps could trap many species of Lepidoptera, Coleoptera and Orthoptera,etc. in 42 days,in which lepidopteron and coleopteron accounted for 43. 47%and 51. 11%,respectively. The total quantity of pests captured by a single lamp was 4 558 during the experiment and the daily average number was 109. Furthermore, the lamps had less effect on natural enemies,and the total quantity of natural enemies trapped by one lamp was 16. The beneficial insect and injurious insect rate was 1∶284 . 88 . The adult amounts of oriental tobacco budworm and Spodoptera litura of the lamp treatment reduced by 57. 14% and 62. 50% respectively compared with the control in field. The quantity of aphids

  3. Effect of sunlight radiation, rainfall and droplet spectra of sprays on persistence of Bacillus thuringiensis deposits after application of DiPel 76AF formulation onto conifers

    International Nuclear Information System (INIS)

    The Effect of sunlight radiation, rainfall and droplet spectra of sprays on per ‐sistence of a Bacillus thuringiensis subspp. kurstaki (Btk) formulation, DiPel? 76AF, was examined after application onto spruce [Picea glauca (Moench) Voss] foliage. The investigation consisted of three studies: (i) Study I: a laboratory microcosm study to examine the photostability of DiPel 76AF deposits on foliage after different periods of exposure to two radiation intensities, (ii) Study II: a laboratory microcosm study to examine the rainfastness of foliar deposits after exposure to different amounts of rainfall consisting of two separate droplet spectra, and (iii) Study III: a field microcosm study to investigate the influence of two different droplet spectra of DiPel 76AF sprays on foliar persistence of Btk under natural weathering conditions. In all studies, persistence of Btk was investigated both by bioassay [using spruce budworm (Choristoneura fumiferana Clemens)] and total protein assay.The findings of Study I indicated that bioactivity of foliar deposits decreased with increasing duration of exposure to radiation, and with increasing radiation intensity. The half‐life (DT50, the exposure period required for 50% of the initial bioactivity to disappear) was 5.1 d for the low intensity, and 3.9 d for the higher intensity. In contrast with the bioassay results, the total protein levels [determined by the bicinchoninic acid (BCA) method] showed no decrease with increasing duration of exposure, or with increasing radiation intensity.The findings of Study II indicated that bioactivity of foliar deposits decreased with increasing cumulative rainfall. A new term, RF50 [the amount of rain (in mm) required to washoff 50% of the initial deposit], was introduced to understand the relationship between rainfall intensity and reduction in bioactivity. When the same amount of rain was applied in different droplet sizes, the RF50 value was high (5.2 mm) for the small rain droplets, and

  4. 陆地棉开花后20d纤维抑制性消减文库的构建及分析%Construction and Analysis of SSH cDNA Library of Fiber in 20 Days Post Anthesis of Upland Cotton

    Institute of Scientific and Technical Information of China (English)

    王少干; 王涛; 袁有禄; 商海红; 计志斌; 闫恒超; 李俊文; 刘爱英; 石玉真; 龚举武; 巩万奎

    2012-01-01

    本研究以高比强度纤维材料0-153和转基因抗虫棉sGK9708为亲本构建的高代重组自交系群体(F6∶9)中选育出的高比强度纤维品系(69307)作为材料,利用抑制性消减杂交技术,以15 DPA纤维为driver、20 DPA纤维为tester,成功构建出陆地棉开花后20 d纤维的cDNA消减文库.通过蓝白斑筛选、菌落PCR及反向Northern技术最终筛选出差异表达的阳性克隆340个.通过对阳性克隆测序及序列分析,共得到1 15个单一序列,其中35个重叠群,80个单拷贝.利用Blast2GO等对差异表达基因进行生物信息学分析,结果表明这些差异表达基因广泛参与糖类、脂类、氨基酸等物质的代谢,以及纤维素生物合成、细胞壁合成与修饰、氧化还原、细胞信号转导等生物学过程.%In this study, one of excellent recombinant inbred line (69307) with high fiber strength was chosen as material from an F6:9 generation of upland cotton (Gossypium Hirsutum L.) derived from the combination between sGK9708 and 0-153. sGk9708 is a commercial transgenic cultivar with resistant to budworm, and 0-153 is a line with high fiber strength. An SSH cDNA library of fiber in 20 days post-anthesis of upland cotton had been successfully constructed via the approach of Suppressive Subtractive Hybridization (SSH), in which the mRNAs isolated from the fibers in 15 days post anthesis (dpa) were used as driver, and the mRNAs from the fibers in 20 days post anthesis (dpa) as tester. Finally, the 340 positive clones expressed differentially had been chosen by Blue-white bolting, colony PCR and Reverse Northern Dot-Blot. 115 unigenes were obtained based on sequencing of the positive clones and analysis of the sequences, which included 35 contigs and 80 singlets. Bioinformatic analysis with Blast2GO software revealed that these differentially expressed genes extensively involved in metabolism of carbohydrate, lipid, amino acid and other substances, and in biological process

  5. Combined Action of Sex Pheromone and Wasp Apanteles gelechiidivoris in Greenhouse Tomato Crops

    Directory of Open Access Journals (Sweden)

    Jessica Andrea Morales

    2014-03-01

    Full Text Available The tomato budworm, Tuta absoluta, is considered main pest of tomato crops. Control of this pest is performed with hemicals, although, there are other strategies such as biological and ethological control. In Colombia there is not precedent that combines both strategies: ethological control with sexual pheromone and biological control with Apanteles gelechiidivoris, for the control of this pest in tomato crops. In this work four different treatments under greenhouse conditions were evaluated including biological control with A. gelechiidivoris, ethological control with sexual pheromone traps, combined action of both controls and traditional control (Chemicals. The experiments aimed to developing a control strategy to reduce populations of T. absoluta. This was done sampling a plant every to 2 meters. From each plant a sample composed by one leaf by stratum was taken and the variables number of total larvae of third instar and parasited and number of captured adults for trap. The maximum parasitism in the population of susceptible larvae was 86.38 % and for total population of larvae was 68.75 %. The combined action of pheromone traps and A. gelechiidivoris presented a greater efficiency and permanence on the control of larvae of T. absoluta.ACCIÓN COMBINADA DE FEROMONA SEXUAL Y DE AVISPAS Apanteles gelechiidivoris PARA EL CONTROL DE Tuta absoluta EN CULTIVOS DE TOMATE BAJO INVERNADEROEl cogollero del tomate, Tuta absoluta, es considerado plaga principal del cultivo de tomate. Su control se realiza con químicos, aunque existen otros tipos de control como el biológico y etológico. En Colombia no existe ningún precedente que involucre la acción combinada de estrategias de control etológico incluyendo feromona sexual y biológico con Apanteles gelechiidivoris para el control de la plaga en cultivos de tomate. En este trabajo, se evaluaron cuatro tratamientos bajo condiciones de invernadero que incluyen control biológico con A

  6. 棉花单宁-黄酮类化合物对棉铃虫的抗性潜力%Potential resistance of tannins-flavoniods in upland cotton against Helicpverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    武予清; 郭予元

    2001-01-01

    Cotton tannins-flavoniods are important compounds associating with the host plant resistant to insect pests and diseases including Heliothis sp. and Helicoverpa sp.. The dosage responses on H. armigera larvae of different compounds are tested. After the 1st instar larvae fed 5 days on the diets contained compounds, the ED50 of larvae on gallocatechin, condensed tannins, rutin and isoquercitrin were 0.81%, 0.49%, 0.57% and 0.83% respectively. The results indicated that there were significantly negative correlation between the concentration of these compounds and the body weight of larvae. But there was irrelevant between concentration of catechin and larvae body weight.The increase of relative larval growth rate was significantly lower than that of the control as the increase of larval feeding amount on the diet separately contained 0.8% gallocatechin, condensed tannins, rutin and isoquercitrin. The results indicated that these compounds are chronic toxins.%陆地棉棉叶甲醇提取物包含了棉花的大部分单宁-黄酮类化合物。这些化合物对棉花多种病虫害具有抗性作用。将这些化合物定量加入人工饲料中饲养棉铃虫1龄幼虫5d,结果表明,棓儿茶素、缩合单宁、芸香苷和异槲皮苷在饲料中的浓度增加均与幼虫体重生长呈显著负相关,ED50分别为0.81%,0.49%,0.57%和0.83%;儿茶素则不存在这种关系;用含0.8%的浓度棓儿茶素、缩合单宁、芸香苷和异槲皮苷的饲料测试棉铃虫,发现随取食量的增加,相对生长率的增加显著低于对照(不含次生物质),即这些物质属于慢毒剂;而儿茶素仅有阻食作用。

  7. Functional Analysis of Polyphenol Oxidases by Antisense/Sense Technology

    Directory of Open Access Journals (Sweden)

    Jutharat Attajarusit

    2007-07-01

    Full Text Available Polyphenol oxidases (PPOs catalyze the oxidation of phenolics to quinones, the secondary reactions of which lead to oxidative browning and postharvest losses of many fruits and vegetables. PPOs are ubiquitous in angiosperms, are inducible by both biotic and abiotic stresses, and have been implicated in several physiological processes including plant defense against pathogens and insects, the Mehler reaction, photoreduction of molecular oxygen by PSI, regulation of plastidic oxygen levels, aurone biosynthesis and the phenylpropanoid pathway. Here we review experiments in which the roles of PPO in disease and insect resistance as well as in the Mehler reaction were investigated using transgenic tomato (Lycopersicon esculentum plants with modified PPO expression levels (suppressed PPO and overexpressing PPO. These transgenic plants showed normal growth, development and reproduction under laboratory, growth chamber and greenhouse conditions. Antisense PPO expression dramatically increased susceptibility while PPO overexpression increased resistance of tomato plants to Pseudomonas syringae. Similarly, PPO-overexpressing transgenic plants showed an increase in resistance to various insects, including common cutworm (Spodoptera litura (F., cotton bollworm (Helicoverpa armigera (Hübner and beet army worm (Spodoptera exigua (Hübner, whereas larvae feeding on plants with suppressed PPO activity had higher larval growth rates and consumed more foliage. Similar increases in weight gain, foliage consumption, and survival were also observed with Colorado potato beetles (Leptinotarsa decemlineata (Say feeding on antisense PPO transgenic tomatoes. The putative defensive mechanisms conferred by PPO and its interaction with other defense proteins are discussed. In addition, transgenic plants with suppressed PPO exhibited more favorable water relations and decreased photoinhibition compared to nontransformed controls and transgenic plants

  8. Regional management strategy of cotton bollworm in China

    International Nuclear Information System (INIS)

    Cotton bollworm Helicoverpa armigera, is one of the most important insect pests in cotton, corn and vegetable production of China. Its regional population dynamics and management strategy derived from Bt-transgenic cotton were investigated in recent years. The researches indicated that the populations of H. armigera in the whole country can be divided into four regional groups, namely, the tropical, subtropical, temperate and Xinjiang geotypes. Their adaptive zones are respectively in southern China, middle and lower Changjiang River Region, including Sichun Province, Hunan Province, Hubei Province and Zhejiang Province etc., Yellow River Region, including Henan Province, Hebei Province, and Shandong Province etc., and the Xinjiang Uygur Autonomous Region and Gansu Province. Based on the analysis of H. armigera population dynamics and climate environment, it is suggested that the Beijing area is probably the northern boundary for the temperate zone geotype of the cotton bollworm. Damage to cotton by larvae of the temperate zone geotype can extend into areas of northeastern China such as Liaoning and Jilin provinces by long distance, facultative migration during the summer East Asia monsoon. Transgenic cotton that expresses a gene from the bacterium Bacillus thuringiensis (Bt) has been deployed for combating the pest since 1997. Its use expanded rapidly to 1.1 million ha in 2000 and 2.8 million ha in 2003, equivalent to 58% of the total cotton area of 4.8 million ha in 2003. The pest management tactics associated with Bt-cotton have resulted in a drastic reduction in insecticide use, which usually caused a significantly increase in populations of beneficial insects and thus contributed to improved natural control of some pests. The risk assessment shows that the natural refuges derived from the mixed planting system of cotton, corn, soybean and peanut on small-scale single-family holdings, play an important function in delaying the development of cotton bollworm

  9. Management of lepidopterans through irradiations

    International Nuclear Information System (INIS)

    suppression by irradiation include Spodoptera litura, S.exigua, S.frugiperda, Helicoverpa armigera, H.zea, Pectinophora gossypiella, Diatraea saccharalis, Cydia pomonella, C.molesta, Ectomyelois ceratoniae, Ephestia kuehniella, Crocidolomia binotalis, Chilo suppressalis, Ostrinia furnacalis, O.nubilalis, Plutella xylostella and Spilosoma obliqua. (author)

  10. Genetic enhancement for grain yield in chickpea – accomplishments and resetting research agenda

    Directory of Open Access Journals (Sweden)

    S.K. Chaturvedi and N. Nadarajan

    2010-07-01

    attention. With the advent of powerful non-conventional approaches fortransferring genes from wild sources and even other genera, it has become possible to develop resistant cultivars for dreaded insectpest like gram pod borer, Helicoverpa armigera Hubner. Hence potential of biotechnological tools must be exploited. The potentialof molecular marker technology in transferring of targeted traits with utmost efficiency or QTLs/ targeted genes has been discussedalong with efforts on mapping and tagging of genes conferring resistance/tolerance to major diseases and abiotic stresses. Thepresent paper deals with the accomplishments’ made and the research agenda for genetic enhancement of grain yield and productionof chickpea in India in near future.

  11. HaSNPV几丁质酶的分离纯化与毒理学研究%Purification and Toxicological Studies of HaSNPV Chitinase

    Institute of Scientific and Technical Information of China (English)

    惠有为; 夏天; 赵亚玲; 贾静芳

    2011-01-01

    Recombinant bacterium GS115-pPIC 9k-ChiA 4.0 fermented chitinase, which was purified by ammomum sulfate precipitation, dialysis , DEAE Sepharose Fast Flow ion exchange chromatography and Sephadex G-1OO gel filtration chromatography, obtained electrophoretically pure chitinase. Rate of recovery was 19. 64% , and purification factor was 17. 74. Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus ( HaSNPV) chitinase toxicological studies carried out by contact toxicity and stomach toxicity, chitinase liquefied Plutella xylostella larvae cell and caused death. The effect and the concentration of chitinase is proportional to time, and the effect caused by stomach toxicity was more intense than by action of contact toxicity. The result of antibacterial experiments which were performed on Helminthosporium sativum , Tomato botrytis cinerea , Tobacco brown spot , and Colletotrichum gloeosporioides , indicated that chitinase can inhibit fungal by enzymatic hydrolysis of chitin in fungal cell wall.%利用重组工程茵GSl 15-pPIC 9k-ChiA 4.0发酵几丁质酶粗液,经(NH4)2SO4盐析、透析、DEAE SepIlarose Fast F1ow离子交换层析以及Sephadex G-100凝胶过滤层析分离纯化,获得电泳纯的棉铃虫单粒包埋型核型多角体病毒(HasNPV)几丁质酶,回收率为19.64%,纯化17.74倍;经HaSNPV几丁质酶毒理学研究,通过触杀作用和胃毒作用,几丁质酶使小菜蛾幼虫细胞液化,导致死亡,其作用效果与几丁质酶浓度和作用时间成正比,且胃毒作用大于触杀作用;经小麦根腐、烟草赤星、番茄灰霉和苹果炭疽等植物病原真菌的抑菌实验,表明几丁质酶可以通过酶解真菌细胞壁中的几丁质达到抑茵作用.

  12. LANDSCAPE CHANGES IN A LOWLAND IN BENIN: ECOLOGICAL IMPACT ON PESTS AND NATURAL ENEMIES.

    Science.gov (United States)

    Boucher, A; Silvie, P; Menozzi, P; Adda, C; Auzoux, S; Jean, J; Huat, J

    2015-01-01

    Habitat management involving conservative biological control could be a good crop pest management option in poor African countries. A survey was conducted from August 2013 to July 2014 in a rainfed lowland region near Pélébina, northern Benin, in order to characterize spatiotemporal landscape changes and investigate their influence on the main crop pests and their associated natural enemies. The area was mapped mainly regarding crop fields and fallows. Visual observations were recorded and a database was compiled. Major landscape composition changes were noted between rainy and dry seasons, which affected the presence of both pests and natural enemies. Cereals (rice, maize and sorghum) and cotton were grown in the humid season, and then okra (Abelmoschus esculentus) was the dominant vegetable crop in dry season. These modifications impacted fallow abundance throughout the lowland. Different cotton (e.g. Helicoverpa armigera, Dysdercus sp., Zonocerus variegatus) or rice (e.g. Diopsis longicornis, D. apicalis) pests were observed during dry season in okra crops. Dry season surveys of Poaceae in two types of fallows ('humid', 'dry') revealed the presence of very few stem borers: only 0.04% of stems sampled were infested by stem borers, with a mean of 1.13 larvae per stem. Known cereal stem borer species such as Busseola fusco, Coniesta ignefusalis, Sesamia calamistis were not clearly identified among these larvae because of their diapausing stage and white color. Unexpected pollinators (Hymenoptera Apidae, genus Braunsapis, Ceratina and Xylocopa) and predators (Crabronidae, genus Dasyproctus) were found in the stems. Sweep-net collection of insects in humid fallows allowed us to describe for the first time in Benin seven Diopsidae species (23% of adults bearing Laboulbeniomycetes ectoparasitic fungi). Some of these species were captured in rice fields during rainy season. Parasitoids (adult Chalcidoidae and Ichneumonoidae) were observed during both seasons but their

  13. Use of natural enemies and biorational pest control of corne

    Directory of Open Access Journals (Sweden)

    Cipriano García Gutiérrez

    2012-09-01

    Full Text Available A general analysis of the potential use of natural enemies and biorational insecticides for control of main pests of corn in thestate of Sinaloa is presented. A discuss on their composition, dosage, toxicity and type of effect on beneficial organisms(natural enemies and pollinators is too included. The work revealed that is possible implement the use of these natural enemies and products for the control of neonate larvae of Spodoptera frugiperda fall armyworm (J. E Smith with Nomuraea rileyi (Farlow (Samson; against thrips Frankliniella occidentalis (Pergande using the nematodes Steinernema riobravis (Cabanillas and Poinar, S. feltiae (Filipjev and Heterorhabditis bacteriophora (Poinar at doses of 10,000 IJ (4x10 ~ IJ/m; against the corn silk fly Euxesta stigmatias (Loew encouraging the natural parasitism of Spalangia sp., while for the cutworm Agrotis ipsilon (Hufnagel can be with spinosad (soluble concentrate at doses of 0.123 kg a. i, and to the corn earwormHelicoverpa zea (Boddie using the analog of methoxyfenozide molting hormone (24% at 144 mg of a. i/L. The biorational control agents that not affect significantly to the natural enemies were the nucleopoliedrosis virus SfMNPV and SeMNPV; N. rileyi and Isaria fumosorosea (Wize; Bacillus thuringiensis (Berlinier; the azadirachtin (neem and parasitoids. In the case of products of chemical synthesis: Spinosad, oxymatrine and bifenthrin showed high rates of mortality in the control of corn pests, so these are considered as of high and moderate risk to Aphis mellifera (L. bees, the methoxyfenozide presented relatively low toxicity to natural enemies. In general, biorational products have repellent effect on larvae and adults of these insects, inhibit feeding and induce molting, also causing deformities and impede the development and growth, too interfere with sexual intercourse and copulate, reducing the oviposition, as well as cause sterility of adults, so these may also constitute a risk to

  14. Stress inducible proteinase inhibitor diversity in Capsicum annuum

    Directory of Open Access Journals (Sweden)

    Mishra Manasi

    2012-11-01

    Full Text Available Abstract Background Wound-inducible Pin-II Proteinase inhibitors (PIs are one of the important plant serine PIs which have been studied extensively for their structural and functional diversity and relevance in plant defense against insect pests. To explore the functional specialization of an array of Capsicum annuum (L. proteinase inhibitor (CanPIs genes, we studied their expression, processing and tissue-specific distribution under steady-state and induced conditions. Inductions were performed by subjecting C. annuum leaves to various treatments, namely aphid infestation or mechanical wounding followed by treatment with either oral secretion (OS of Helicoverpa armigera or water. Results The elicitation treatments regulated the accumulation of CanPIs corresponding to 4-, 3-, and 2-inhibitory repeat domains (IRDs. Fourty seven different CanPI genes composed of 28 unique IRDs were identified in total along with those reported earlier. The CanPI gene pool either from uninduced or induced leaves was dominated by 3-IRD PIs and trypsin inhibitory domains. Also a major contribution by 4-IRD CanPI genes possessing trypsin and chymotrypsin inhibitor domains was specifically revealed in wounded leaves treated with OS. Wounding displayed the highest number of unique CanPIs while wounding with OS treatment resulted in the high accumulation of specifically CanPI-4, -7 and −10. Characterization of the PI protein activity through two dimensional gel electrophoresis revealed tissue and induction specific patterns. Consistent with transcript abundance, wound plus OS or water treated C. annuum leaves exhibited significantly higher PI activity and isoform diversity contributed by 3- and 4-IRD CanPIs. CanPI accumulation and activity was weakly elicited by aphid infestation yet resulted in the higher expression of CanPI-26, -41 and −43. Conclusions Plants can differentially perceive various kinds of insect attacks and respond appropriately through activating

  15. Insect Resistance to Bacillus thuringiensis Toxin Cry2Ab Is Conferred by Mutations in an ABC Transporter Subfamily A Protein.

    Directory of Open Access Journals (Sweden)

    Wee Tek Tay

    2015-11-01

    Full Text Available The use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of insecticide resistance. Transgenic crops (e.g., cotton expressing the Bt Cry toxins are now used world wide to control these pests, including the highly polyphagous and invasive cotton bollworm Helicoverpa armigera. Since 2004, the Cry2Ab toxin has become widely used for controlling H. armigera, often used in combination with Cry1Ac to delay resistance evolution. Isolation of H. armigera and H. punctigera individuals heterozygous for Cry2Ab resistance in 2002 and 2004, respectively, allowed aspects of Cry2Ab resistance (level, fitness costs, genetic dominance, complementation tests to be characterised in both species. However, the gene identity and genetic changes conferring this resistance were unknown, as was the detailed Cry2Ab mode of action. No cross-resistance to Cry1Ac was observed in mutant lines. Biphasic linkage analysis of a Cry2Ab-resistant H. armigera family followed by exon-primed intron-crossing (EPIC marker mapping and candidate gene sequencing identified three independent resistance-associated INDEL mutations in an ATP-Binding Cassette (ABC transporter gene we named HaABCA2. A deletion mutation was also identified in the H. punctigera homolog from the resistant line. All mutations truncate the ABCA2 protein. Isolation of further Cry2Ab resistance alleles in the same gene from field H. armigera populations indicates unequal resistance allele frequencies and the potential for Bt resistance evolution. Identification of the gene involved in resistance as an ABC transporter of the A subfamily adds to the body of evidence on the crucial role this gene family plays in the mode of action of the Bt Cry toxins. The structural differences between the ABCA2, and that of the C subfamily required for Cry1Ac toxicity, indicate differences in the

  16. Insect Resistance to Bacillus thuringiensis Toxin Cry2Ab Is Conferred by Mutations in an ABC Transporter Subfamily A Protein.

    Science.gov (United States)

    Tay, Wee Tek; Mahon, Rod J; Heckel, David G; Walsh, Thomas K; Downes, Sharon; James, William J; Lee, Sui-Fai; Reineke, Annette; Williams, Adam K; Gordon, Karl H J

    2015-11-01

    The use of conventional chemical insecticides and bacterial toxins to control lepidopteran pests of global agriculture has imposed significant selection pressure leading to the rapid evolution of insecticide resistance. Transgenic crops (e.g., cotton) expressing the Bt Cry toxins are now used world wide to control these pests, including the highly polyphagous and invasive cotton bollworm Helicoverpa armigera. Since 2004, the Cry2Ab toxin has become widely used for controlling H. armigera, often used in combination with Cry1Ac to delay resistance evolution. Isolation of H. armigera and H. punctigera individuals heterozygous for Cry2Ab resistance in 2002 and 2004, respectively, allowed aspects of Cry2Ab resistance (level, fitness costs, genetic dominance, complementation tests) to be characterised in both species. However, the gene identity and genetic changes conferring this resistance were unknown, as was the detailed Cry2Ab mode of action. No cross-resistance to Cry1Ac was observed in mutant lines. Biphasic linkage analysis of a Cry2Ab-resistant H. armigera family followed by exon-primed intron-crossing (EPIC) marker mapping and candidate gene sequencing identified three independent resistance-associated INDEL mutations in an ATP-Binding Cassette (ABC) transporter gene we named HaABCA2. A deletion mutation was also identified in the H. punctigera homolog from the resistant line. All mutations truncate the ABCA2 protein. Isolation of further Cry2Ab resistance alleles in the same gene from field H. armigera populations indicates unequal resistance allele frequencies and the potential for Bt resistance evolution. Identification of the gene involved in resistance as an ABC transporter of the A subfamily adds to the body of evidence on the crucial role this gene family plays in the mode of action of the Bt Cry toxins. The structural differences between the ABCA2, and that of the C subfamily required for Cry1Ac toxicity, indicate differences in the detailed mode

  17. LANDSCAPE CHANGES IN A LOWLAND IN BENIN: ECOLOGICAL IMPACT ON PESTS AND NATURAL ENEMIES.

    Science.gov (United States)

    Boucher, A; Silvie, P; Menozzi, P; Adda, C; Auzoux, S; Jean, J; Huat, J

    2015-01-01

    Habitat management involving conservative biological control could be a good crop pest management option in poor African countries. A survey was conducted from August 2013 to July 2014 in a rainfed lowland region near Pélébina, northern Benin, in order to characterize spatiotemporal landscape changes and investigate their influence on the main crop pests and their associated natural enemies. The area was mapped mainly regarding crop fields and fallows. Visual observations were recorded and a database was compiled. Major landscape composition changes were noted between rainy and dry seasons, which affected the presence of both pests and natural enemies. Cereals (rice, maize and sorghum) and cotton were grown in the humid season, and then okra (Abelmoschus esculentus) was the dominant vegetable crop in dry season. These modifications impacted fallow abundance throughout the lowland. Different cotton (e.g. Helicoverpa armigera, Dysdercus sp., Zonocerus variegatus) or rice (e.g. Diopsis longicornis, D. apicalis) pests were observed during dry season in okra crops. Dry season surveys of Poaceae in two types of fallows ('humid', 'dry') revealed the presence of very few stem borers: only 0.04% of stems sampled were infested by stem borers, with a mean of 1.13 larvae per stem. Known cereal stem borer species such as Busseola fusco, Coniesta ignefusalis, Sesamia calamistis were not clearly identified among these larvae because of their diapausing stage and white color. Unexpected pollinators (Hymenoptera Apidae, genus Braunsapis, Ceratina and Xylocopa) and predators (Crabronidae, genus Dasyproctus) were found in the stems. Sweep-net collection of insects in humid fallows allowed us to describe for the first time in Benin seven Diopsidae species (23% of adults bearing Laboulbeniomycetes ectoparasitic fungi). Some of these species were captured in rice fields during rainy season. Parasitoids (adult Chalcidoidae and Ichneumonoidae) were observed during both seasons but their

  18. Screening and Identification of Differentially Expressed Genes Induced by Cotton Bollworm Infestation from Cotton Plants with cDNA Microarray Method%基因芯片技术鉴定棉铃虫胁迫后棉花差异表达基因

    Institute of Scientific and Technical Information of China (English)

    武娟; 齐放军; 田文华; 韩榕; 张永军; 郭予元

    2011-01-01

    In general, gene expression changes when cotton is infested by phytophagous insects. Screening and identification of these regulatory genes induced by cotton bollworm (Helicoverpa armigera Hiibner) infestation will help us understand the molecular mechanism of the host plants resistance to insect pests. In this paper, cotton {Gossypium spp.cv. Zhongl2) was as test material. The cotton plants were divided into control groups and pest stress treatment groups (including 6, 12, 24 and 48 h, pest stress treatments, respectively). The total RNA were extracted from control groups and different pest stress treatments, and the Affymetrix cotton gene chip analysis were applied to explore gene expression profiles. It was found that a total of 4 109 genes (28%) in leaves weredifferentially expressed after induced 6 h, 1 917 of them was up-regulated and 2 192 of them was down-regulated, respectively. After 12 h, a total of 2 605 genes(l 8%) were differentially expressed, 1 326 of them was up-regulated and 1 279 of them was down-regulated, separately. After 24 h, a total of 3 213 genes (22%) were differentially expressed, 1 424 of them is up-regulated and 1 789 of them was down-regulated, respectively. After 48 h, a total of 2 763 genes (19%) were differentially expressed, 1 450 of them was up-regulated and 1 313 of them is down-regulated, separately. Bioinformatics analysis revealed that function of some differentially expressed genes involved roxidative stress response, defense response, signal transduction, transcriptional regulation, flavone and flavonol biosynthesis, terpenoids synthesis and metabolism, biosynthesis of alkaloids derived from many kinds of amino acids, etc. Furthermore, some potential genes which regulate specific volatiles emission in cotton were also identified. It was found that the gene expression of farnesyl pyrophosphate synthase was regulated by circadian rhythm. Meanwhile, (+)-delta-cadinenesynthase gene expression level increased when cotton plants

  19. Screening of Bt isolates with insecticidal activity against Apolygus lucorum (Heteroptera:Miridae)and bioassay of Cry15Aa polypeptides%对绿盲蝽具有杀虫活性Bt菌株的筛选及Cry15Aa蛋白活性的研究

    Institute of Scientific and Technical Information of China (English)

    张学雯; 束长龙; 陆宴辉; 刘春颖; 张杰; 高继国

    2016-01-01

    Transgenic cotton with cry genes has controlled the main cotton pests (Helicoverpa armigera )effective-ly,however another non target mirid bugs (Heteroptera:Miridae)with sucking mouthparts have increased popu-lation sizes year by year.It has not been reported to the effective insecticidal genes of Bacillus thuringiensis a-gainst Apolygus lucorum (Meyer-Dür),in this study,Bt insecticidal genes and isolates stored in our laboratory were prepared to assay the insecticidal activity against A.lucorum .The cry 15Aa gene which belongs to Mtx in our lab was used to perform the bioassay to A.lucorum ,the result showed that Cry15Aa polypeptides was certain insecticidal activity against A.lucorum .After bioassay against A.lucorum ,twenty A.lucorum toxic Bt isolates were obtained.The LC-MS/MS identification showed these isolates might contains Cry1Aa,Cry1Ab,Cry1Ac, Cry1Ae,Cry1Af,Cry1Ag,Cry1Ah,Cry1Ba,Cry1Be,Cry8Ha and other proteins which are insecticidal to lepi-doptera and coleopteran pests,and four of them contains peptide fragment similar to Cry15Aa which belong to Mtx protein.But subsequence gene identification results indicated that these isolates not contains full length cry 15Aa gene,it suggested that these isolates contains new cry 15 type genes.The results indicated that these Bt i-solates may contain new insecticidal proteins toxic to mirid bugs.The obtaining of novel Bt isolates and the discovery of Cry15Aa with insecticidal activity against A.lucorum are significant to the biological control for A.lucorum .%Bt 棉有效控制了棉田主要害虫棉铃虫(Helicoverpa armigera ),然而原来处于次要地位的刺吸式口器害虫盲蝽(Heteroptera:Miridae)为害逐年加重,目前对绿盲蝽(Apolygus lucorum Meyer-Dür)有效的抗虫基因未见报道。本研究以本实验室保存的 Bt 杀虫基因和菌株为材料,对绿盲蝽进行杀虫活性筛选。利用本实验室先前克隆的Mtx 类杀虫基因 cry15Aa 表达产物进行绿

  20. PROTEASES AND PROTEASE INHIBITORS INTERACTION: DEFENCE STRATEGY AGAINST

    Directory of Open Access Journals (Sweden)

    R.S.DHANDE 1 N.J.CHIKHALE 2

    2014-12-01

    Full Text Available ABSTRACT: An increase in crop yield, its management and preservation are among the main challenges standing before the human population that exceed 10 billion by the mid of 21 st  century.  Every year, considerable agricultural losses occur due to repeated practices of cultivation of large genetically similar populations.  Such cultivation practices favors incidence of more insect pests (Hilder and Boulter, 1999;  Oerke  et  al.,  1994;  Smith,  1999.  To  solve  these  problems,  current approaches  rely  on  use  of  synthetic  chemicals  like  fertilizers,  insecticides, herbicides,  fungicides  etc.  But  this  exerts  excessively  high  pressure  on environment  and  destabilizes  the  ecological  balance.  The  traditional  pest control method involves the use of conventional pesticides, most of which are non-specific and wipe out the entire community, pollutes the agro-ecosystem, and  increases  the  cost  of  production.  The  emergence  of  gene  transfer technology  has  solved  some  problems  regarding  overuse  of  chemical pesticides.  The  delta  endotoxin  encoding  gene  from  Bacillus  thuringiensis,  a gram positive soil borne bacteria transferred in crops has given little relief from coleopterans and lepidopterans attack.  Whereas, the insects belonging to these orders like Helicoverpa Sps. have developed resistance against Bt toxins. The other approach takes advantage of use of plant genes encoding defense proteins like protease inhibitors which is more appealing, simpler and safer (Dunaevsky et.  al.,  2005.  Proteinase  inhibitors  (PIs  are  naturally  occurring  proteins  in living organisms and are able to inhibit & control the activity of proteases. PIs act  on  an  active  site  of  digestive  proteolytic  enzymes  and  form  a  stable complex  unlike  enzyme-substrate  or  enzyme-product  weak  complexes  which

  1. 棉铃虫硫氧还蛋白类似基因HaTrx-like的分子鉴定和抗逆特征

    Institute of Scientific and Technical Information of China (English)

    张松斗; 张博宇; 申忠健; 刘彦君; 李贞; 张青文; 刘小侠

    2015-01-01

    【目的】克隆棉铃虫Helicoverpa armigera硫氧还蛋白类似基因(Ha Trx-like)的cDNA全长并进行序列分析,研究HaTrx-like基因的时间和空间表达模式以及参与抵抗机械损伤、紫外线照射和极端温度等逆境的特征。【方法】利用RT-PCR的方法扩增得到Ha Trx-like基因的全长cDNA并通过测序进行验证,运用几种生物信息学软件对基因和氨基酸序列进行分析,利用荧光定量PCR检测HaTrx-like基因的时间和空间分布以及4种逆境条件处理后的表达模式。【结果】棉铃虫HaTrx-like基因的c DNA全长为526 bp,其中开放阅读框长度为381 bp,编码126个氨基酸,含有一个保守的氧化还原活性位点CXXC,其氨基酸序列和帝王斑蝶Danaus plexippus以及家蚕Bombyx mori同源物的序列一致性为72%和71%。HaTrx-like基因在幼虫5龄0 h和5龄96 h,蛹期第1天和第5天,以及成虫第1天的表达量相对较高,在幼虫的中肠、马氏管和成虫的肌肉中的表达量相对较高。在机械损伤、紫外线照射、极端低温和高温处理后,该基因的表达均显著地升高。【讨论】获得了棉铃虫HaTrx-like基因的cDNA全长,并初步鉴定该基因为硫氧还蛋白家族成员,其表达水平受到机械损伤、紫外线照射和极端温度的上调,为进一步深入研究昆虫中硫氧还蛋白家族基因的各种生理功能提供理论基础。

  2. Changes in the Contents of Proteins and Amino Acids of Apriona germari Larvae Infected by Beauveria bassiana%桑天牛幼虫感染球孢白僵菌后蛋白质和氨基酸含量的变化

    Institute of Scientific and Technical Information of China (English)

    李会平; 黄大庄; 唐秀光

    2012-01-01

    ;Felipe et al.,2004).近年来,利用白僵菌防治松毛虫(Dendrolimus spp,)、玉米螟(Pyrausta nubilalis)、棉铃虫(Helicoverpa armigera)、美国白蛾(Hyphantria cunea)、天牛等农林害虫的研究和应用均取得很大进展,在控制农林害虫的严重发生和减少环境污染方面,发挥着不可替代的作用(赫英伟,2010;王滨,2003;丁德贵等,2004;张爱文等,1992;孙鲁娟等,2001;郭志红等,2001;刘洪剑等,2007;Shmazu,1995;徐均焕等,2003;林庆源,2005;刘洪剑等,2009;王云滨,2007;陆秀君等,2008).

  3. Isotopes and trace elements as geo-location markers for biosecurity: determining the origin of exotic pests.

    Science.gov (United States)

    Holder, Peter W.; Armstrong, Karen; Clough, Tim; Frew, Russell; van Hale, Robert; Baker, Joel A.; Millet, Marc-Alban

    2010-05-01

    Background. The benefits of accurate point of origin discrimination in biosecurity include achieving appropriate operational responses in exotic pest eradication and post-border incursion campaigns, and identifying risk pathways. Reading natural abundance biogeochemical markers via mass spectrometry methods is a powerful tool for tracing ecological pathways and provenance determination of agricultural products and items of forensic interest. However, the application of these methods to trace insects - man's most damaging competitors - has been underutilised to date and our understanding in this field is still in a phase of basic development. Stable isotope ratio analyses using δ2H, δ13C have given spatial resolution in the monarch butterfly, single host system in eastern North America. Subsequently, the same method was employed in an attempt to determine the origin of important biosecurity pests in New Zealand. However, the results were contentious as the accuracy and limitations of the method in a biosecurity application were unknown. Further investigation has shown the value of existing invertebrate stable isotope geo-location methodology (i.e., using only two light elements) is tenuous in the biosecurity context, where the sample sizes are usually only one or two insects, and the specimens are generally polyphagous and accidentally introduced, and so from an unknown and unpredictable place, point in time and host: The spatial distribution of 2H in New Zealand may not be reliable over insect life-span time-scales; and fractional variables are un-quantified and potentially overwhelm any New Zealand signal. Further, the geo-location value of 13C is uncertain, especially for polyphagous insects. Research aims. The internationally distributed Helicoverpa armigera [Noctuidae] is being used to examine the processes fundamental to the location-to-plant-to-insect biogeochemical profile imprinting in phytophagous insects, including the turn over of elements in adult

  4. Resistance Evaluation of Btcry1Ah-transgenic Maize to Asian Corn Borer,Cotton Bollworm and Oriental Armyworm%转Bt cry1Ah基因抗虫玉米对亚洲玉米螟、棉铃虫和黏虫的抗性评价

    Institute of Scientific and Technical Information of China (English)

    宋苗; 汪海; 张杰; 何康来; 梁革梅; 朱莉; 黄大昉; 郎志宏

    2016-01-01

    Bt cry1Ah gene was transferred into inbred line maize Zong31 via Agrobacterium-mediated method,and transgenic maize HGK60 with significant resistance to corn borer was acquired. In order to investigate its insecticidal activity to Lepidoptera pests,we evaluated the insecticidal effects of HGK60 to Asian corn boner(Ostrinia furnacalis),cotton bollworm(Mythimna separate(Walker))and oriental armyworm(Helicoverpa armigeraHubne)through laboratory and field bioassay. The results of laboratory bioassay indicated that no Asian corn boner feeding on HGK60 leaves survived. HGK60 presented the toxic effect on neonate of cotton bollworm,and different tissues of it had different insecticidal effects. Compared to the non-transgenic maize,the body-weight of armyworm neonate was significantly inhibited after a week of feeding HGK 60 leaves. The results of field bioassay showed that HGK60 had solid insecticidal effects to O. furnacalis and H. armigera in high resistance level,while the efficacy to M. separate was in resistance level.%利用农杆菌介导法将Btcry1Ah基因转入玉米自交系综31,获得对玉米螟有显著抗性的转基因玉米HGK60,为了研究其对鳞翅目害虫的杀虫活性,在室内和田间分别用亚洲玉米螟、棉铃虫和黏虫幼虫对HGK60玉米的杀虫效果进行检测。室内生物活性检测结果表明,取食HGK60玉米心叶的亚洲玉米螟幼虫在3d后死亡率达100%;HGK60玉米对棉铃虫幼虫有毒杀作用,玉米不同部位对棉铃虫幼虫的杀虫效果存在差异;与非转基因玉米对照相比,取食HGK60玉米叶片一周后的黏虫幼虫体重增长明显受到抑制。田间生物活性检测结果表明,HGK60玉米对于亚洲玉米螟和棉铃虫有很强的杀虫活性,达到高抗级别,对于黏虫有一定的杀虫活性,为抗性级别。

  5. Cloning, Expression and Analysis of Insecticidal Activity of a Novel vip 3A a-type Gene from Bacillus thuringiensis%苏云金芽胞杆菌新型vip3Aa基因的克隆、表达与活性分析

    Institute of Scientific and Technical Information of China (English)

    何晓明; 束长龙; 刘晓垒; 李海涛; 高继国; 张杰; 宋福平

    2011-01-01

    To find novel vip3 genes, the vip3-type genes in 72 Bt stains were identified by PCR method and high-resolution melting analysis (HRMA) system. The results indicated that three vip3 gene types, vip3Aa, vip3Af and vip3Ba were found in 18 positive strains. A full-length vip3 gene fragment, which obtained by PCR amplification with a pair of primers designed according to lupJ-type gene sequences and DNA from T03B001 (B. Thuringiensis subsp. Sumiyoshiensis) as template, was introduced into expression vector pEB and transformed into Escherichia coli Rosetta (DE3). At low temperatures, a peptide of 88 kD was expressed by IPTG induction. Theencoded protein was composed of 789 amino acid rsidues. It shared a 96% sequence homology with Vip3Aa protein. This gene designated as vip3A a39 by International Nomenclature Committee of Bt endotoxin, GenBank accession No. Was HMI17631. Vip3Aal 1 protein was obtained in our previous study, 39 amino acid residues were found to be different between the Vip3Aa39 and Vip3Aal 1 proteins. Insecticidal activities of soluble expressed products of vip3Aa39 and vip3Aall genes were tested against Agrotis ipsilon, Plutella xylostella, Helicoverpa armigera and Spodoptem exigua by feeding method. The bioassay results indicated that Vip3Aa39 had insecticidal activity against A.ipsilon with 50% lethal concentration (LCX) of 5.43 |xg/mL compared to 73.62 p-g/mL for Vip3Aal 1; Vip3Aa39 showed insecticidal activity against P.xylostella with LCX of 140.64 (xg/mL while Vip3Aal 1 protein had no activity against P.xylostella; Vip3Aal 1 demonstrated insecticidal activity against H.armigera with LCX of 35.18 |xg/mL compared to 286.99 |xg/mL for Vip3Aa39; Vip3Aa39 had insecticidal activity against S. Exigua with LCX of 2.02 |xg/mL similar to 2.04 |xg/mL for Vip3Aal 1. The results indicated that insecticidal activity of Vip3Aa39 and Vip3Aal 1 was different from each other against A.ipsilon, P.xylostella and H.armigera. Compared with the Vip3Aall, Vip3Aa39 had

  6. 转基因作物对生物多样性的影响%Effect of transgenic crops on biodiversity

    Institute of Scientific and Technical Information of China (English)

    钱迎倩; 魏伟; 桑卫国; 马克平

    2001-01-01

    Effect of transgenic crops on biodiversity is one of important environmental issues. Concerned experimental reports have been published recently. It was reported by Xia Jingyuan et al. that transgenic Bt cotton in field trial harms seriously the parasitic rate, emergence rate and quality of cocoon of Campoletis chlorideae and Microplitis sp.,and the dominant parasitic natural enemies of the larvae of bollworm (Helicoverpa armigera). Results on convincible experiments were published by entomologists, especially Losey's et al. results that transgenic pollen harms monarch larvae in his laboratory assay, published on Nature (399: 214, 20 May, 1999), caused strong repercussions worldwide.The U.S. government hold uncompromising stand on the effect of GMOs on potential ecological risks and public health, started to become flexible. USDA Secretary announced a new biotechnology advisory committee that will bring advice from a wide range of biotech stakeholders. Two U.S. processing companies that represent nearly half of the U.S. corn-processing market, announced that they will no longer accept transgenic corn varieties that are not approved by the EU. EU announced on May 21, the next day after publishing of Losey′s paper, that it would freeze its approval pending further investigation. UK recently announced it would wait 3 years before approving crops with built-in Bt; Austria, Luxembourg and Norway have banned the corn in spite of EU approval; Greece voted against the EU approval. Scientific and technological circles and the public opinions vary. Related Ministries and Agencies in our country have to pay enough attention, especially to strengthen the studies on the effect of GMOs on the potential ecological risks and public health and the monitoring after release of GMOs in the commercialized scale.%转基因作物对生物多样性的影响是重要的环境问题之一,近年来,已有这类实验的报道。夏敬源等的研究说明大田种植转基因Bt抗虫