WorldWideScience

Sample records for budworm helicoverpa assulta

  1. 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

  2. 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

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

    Czech Academy of Sciences Publication Activity Database

    Zhao, X. C.; Dong, J. F.; Tang, Q. B.; Yan, Y. H.; Gelbič, Ivan; Van Loon, J. J. A.; Wang, C. Z.

    2005-01-01

    Roč. 95, č. 5 (2005), s. 409-416 ISSN 0007-4853 Grant - others:Chinese Academy of Sciences(CN) KSCX2-SW-105; Major State Basic Research Project of China(CN) 2000016208; National Natural Science Foundation of China(CN) 30330100 Institutional research plan: CEZ:AV0Z50070508 Keywords : Helicoverpa armigera * Helicoverpa assulta * Noctuidae Subject RIV: ED - Physiology Impact factor: 1.333, year: 2005

  4. Perspective of using the sterile insect technique for Tobacco Budworms Heliothis virescens (Lepidoptera: Noctuidae) and Cotton Bollworm Helicoverpa armigera (Lepidoptera: Noctuidae) in cotton crop as an alternative method of control

    International Nuclear Information System (INIS)

    Haddad, Gianni Queiroz

    2017-01-01

    Since the 1950s, scientists have used ionizing radiation to sterilize insects, which are released in nature to mate, but without any progeny. Known as the sterile insect technique (TIE), this method of insect control has traditionally used ionizing radiation to sterilize insects, a technique that does not generate residues, and can act in synergy with the other techniques within integrated pest management. For several years, Brazil has been fighting against the increase of pests, introducing new tactics and techniques within the IPM programs, to overcome the resistance of chemical products, such as: reducing the residues of agrochemicals; For some important crops of our country, we have a wide spectrum of pests occurring from the beginning to the end of the harvest, one of them is the cotton crop and among the key pests of this crop, we have some extremely important caterpillars, among them Heliothis virescens and Helicoverpa armigera These species are morphologically similar, the second being identified a few years ago in Brazil. There are still no studies in Brazil using TIE as an additional tool for Lepidoptera, therefore the purpose of this study was to evaluate the effect of doses of gamma radiation in the different phases of the evolutionary cycle of Heliothis virescens and Helicoverpa armigera, as well as to evaluate the sterility in generation P And the ability of insects to irradiate with non-irradiated insects. The pupal phase presented the best result because 75 Gy achieved sterility in Heliothis virecens and 100 Gy sterilized Helicoverpa armigera, therefore it contemplated the phase and dose chosen to evaluate the competition between the irradiated insects and the normal insects of both species. Both Heliothis virecens and Helicoverpa armigera presented a satisfactory result, as the irradiated insects managed to significantly reduce the viability of the eggs in a ratio of 9: 1: 1. (author)

  5. Perspective of using the sterile insect technique for Tobacco Budworms Heliothis virescens (Lepidoptera: Noctuidae) and Cotton Bollworm Helicoverpa armigera (Lepidoptera: Noctuidae) in cotton crop as an alternative method of control; Perspectiva de utilizacao da Tecnica do Inseto Esteril para lagarta da maca Heliothis virescens (Lepidoptera: Noctuidae) e lagarta do velho mundo Helicoverpa armigera (Lepidoptera: Noctuidae) na cultura do algodoeiro como um metodo alternativo de controle

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, Gianni Queiroz

    2017-07-01

    Since the 1950s, scientists have used ionizing radiation to sterilize insects, which are released in nature to mate, but without any progeny. Known as the sterile insect technique (TIE), this method of insect control has traditionally used ionizing radiation to sterilize insects, a technique that does not generate residues, and can act in synergy with the other techniques within integrated pest management. For several years, Brazil has been fighting against the increase of pests, introducing new tactics and techniques within the IPM programs, to overcome the resistance of chemical products, such as: reducing the residues of agrochemicals; For some important crops of our country, we have a wide spectrum of pests occurring from the beginning to the end of the harvest, one of them is the cotton crop and among the key pests of this crop, we have some extremely important caterpillars, among them Heliothis virescens and Helicoverpa armigera These species are morphologically similar, the second being identified a few years ago in Brazil. There are still no studies in Brazil using TIE as an additional tool for Lepidoptera, therefore the purpose of this study was to evaluate the effect of doses of gamma radiation in the different phases of the evolutionary cycle of Heliothis virescens and Helicoverpa armigera, as well as to evaluate the sterility in generation P And the ability of insects to irradiate with non-irradiated insects. The pupal phase presented the best result because 75 Gy achieved sterility in Heliothis virecens and 100 Gy sterilized Helicoverpa armigera, therefore it contemplated the phase and dose chosen to evaluate the competition between the irradiated insects and the normal insects of both species. Both Heliothis virecens and Helicoverpa armigera presented a satisfactory result, as the irradiated insects managed to significantly reduce the viability of the eggs in a ratio of 9: 1: 1. (author)

  6. User's guide to the western spruce budworm modeling system

    Science.gov (United States)

    Nicholas L. Crookston; J. J. Colbert; Paul W. Thomas; Katharine A. Sheehan; William P. Kemp

    1990-01-01

    The Budworm Modeling System is a set of four computer programs: The Budworm Dynamics Model, the Prognosis-Budworm Dynamics Model, the Prognosis-Budworm Damage Model, and the Parallel Processing-Budworm Dynamics Model. Input to the first three programs and the output produced are described in this guide. A guide to the fourth program will be published separately....

  7. Labeling Feral Spruce Budworm (Lepidoptera: Tortricidae) Populations With Rubidium.

    Science.gov (United States)

    MacKinnon, Wayne; Eveleigh, Eldon; Silk, Peter; Forbes, Glen

    2016-04-01

    Rubidium (Rb) is a trace element that occurs naturally in low concentrations and is easily absorbed by plants, making it a useful tool for labeling insect defoliators, such as spruce budworm (Choristoneura fumiferana Clemens). Balsam fir trees (Abies balsamea (L.) Miller) injected with either 8 or 16 g per tree of rubidium chloride (RbCl) showed quick uptake and distribution throughout the crown, with no negative effects on tree shoot growth or spruce budworm survival and development. Adult spruce budworm that fed as larvae on trees injected with RbCl were clearly labeled, with significantly higher Rb concentrations than the background levels found in adults that fed as larvae on control trees. Rb concentrations in feral spruce budworm adults for both the 8 g (9 µg/g) and 16 g (25 µg/g) per tree treatments were at least five times lower than those in laboratory-reared adults on 1,000 µg/g RbCl diet (125 µg/g); survival, development, pupal weight, sex ratio, and mating status of spruce budworm were not adversely affected by Rb treatment. Egg masses laid by feral females that fed as larvae on Rb-labeled trees were also labeled with Rb. Injecting trees with RbCl is a viable technique for labeling feral spruce budworm populations to help distinguish local populations from immigrants to better evaluate the success of early intervention strategies such as mating disruption. © Crown copyright 2016.

  8. Harvesting budworm-damaged stands for fuel

    Energy Technology Data Exchange (ETDEWEB)

    Henley, S.G. (York, Sunbury, Charlotte Wood Products Marketing Board, (Canada))

    1985-01-01

    This project was initiated to demonstrate the economics and logistics of harvesting budworm-damaged stands for use as fuel. Dead spruce and balsam fir were to be harvested from small private woodlots in southwestern New Brunswick, using an integrated, full-tree harvesting system to produce wood chip fuel and other forest products. The overall objectives of the study are listed. The harvesting equipment and the selection of sites are discussed. The most efficient methods of finding candidate woodlots was found to be by advertising and word of mouth. Contact was made with 85 woodlot owners, and 45 woodlots were visited and evaluated for their suitability. A further 150 management plans were screened and rejected for various reasons. Only 2 woodlots were initially recognized as potential sites; however, after showing some interest, the owners decided not to participate. The reasons for the rejection of the various woodlots are listed. The fact that a number of owners were against clearcutting, and, in some cases, against any cutting, and that others showed no interest in the study, is attributed to the high percentage of white-collar workers owning woodlots. Other strategies for harvesting dead or scrap wood are suggested. 1 ref., 1 tab.

  9. Spruce budworm core B.t. test - 1980 combined summary

    Science.gov (United States)

    Gerald S. Walton; Franklin B. Lewis

    1982-01-01

    Two commercial preparations of Bacillus thuringiensis (Bet.) were aerially applied in 1980 to populations of spruce budworm (Choristoneura fumiferana (Clem.)) in Arizona, Maine, New Hampshire, and Wisconsin. Operations were conducted under the auspices of CANUSA-East with standardized procedures for spray application and population...

  10. The sequence of the Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus genome

    NARCIS (Netherlands)

    Chen, X.; IJkel, W.F.J.; Tarchini, R.; Sun, X.; Sandbrink, H.; Wang, H.; Peters, S.; Zuidema, D.; Klein Lankhorst, R.; Vlak, J.M.; Hu, Z.

    2001-01-01

    The nucleotide sequence of the Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV) DNA genome was determined and analysed. The circular genome encompasses 131 403 bp, has a G C content of 39.1 molnd contains five homologous regions with a unique pattern of repeats.

  11. Drought-triggered western spruce budworm outbreaks in the Interior Pacific Northwest: A multi-century dendrochronological record

    Science.gov (United States)

    A. Flower; D. G. Gavin; E. K. Heyerdahl; R. A. Parsons; G. M. Cohn

    2014-01-01

    Douglas-fir forests in the interior Pacific Northwest are subject to sporadic outbreaks of the western spruce budworm, a species widely recognized as the most destructive defoliator in western North America. Outbreaks of the western spruce budworm often occur synchronously over broad regions and lead to widespread loss of leaf area and decrease in growth rates in...

  12. Emamectin benzoate: new insecticide against Helicoverpa armigera.

    Science.gov (United States)

    Fanigliulo, A; Sacchetti, M

    2008-01-01

    Emamectin benzoate is a new insecticide of Syngenta Crop Protection, with a new mechanism of action and a strong activity against Lepidoptera as well as with and a high selectivity on useful organisms. This molecule acts if swallowed and has some contact action. It penetrates leaf tissues (translaminar activity) and forms a reservoir within the leaf. The mechanism of action is unique in the panorama of insecticides. In facts, it inhibits muscle contraction, causing a continuous flow of chlorine ions in the GABA and H-Glutamate receptor sites. During 2006 and 2007, experimentation was performed by the Bioagritest test facility, according to EPPO guidelines and Principles of Good Experimental Practice (GEP), aiming at establishing the biological efficacy and the selectivity of Emamectin benzoate on industry tomato against Helicoverpa armigera (Lepidoptera: Noctuidoe). The study was performed in Tursi-Policoro (Matera), southern Italy. Experimental design consisted in random blocks, in 4 repetitions. A dosage of 1.5 Kg/ha of the formulate was compared with two commercial formulates: Spinosad 0.2 kg/ha (Laser, Dow Agrosciences Italia) and Indoxacarb 0.125 kg/ha (Steward EC insecticide, Dupont). Three foliage applications were applied every 8 days. The severity of damage induced by H. armigera was evaluated on fruits. Eventual phytotoxic effects were also evaluated. Climatic conditions were optimal for Lepidoptera development, so that the percentage of fruits attacked in 2007 at the first scouting was 68.28%. Emamectin benzoate has shown, in two years of testing, a high control of H. armigera if compared with the standards Indoxacarb and Spinosad. No effect of phytotoxicity was noticed on fruits.

  13. The preliminary studies on parasitization of Trichogramma chilonis on Helicoverpa armigera eggs and eggs from irradiated Helicoverpa armigera moths

    International Nuclear Information System (INIS)

    Wang Endong; Lu Daguang; Liu Xiaohui; Li Yongjun; Zhang Shuyong; Liu Qiongru; Wang Huasong

    2002-01-01

    The parasitization rates of Trichogramma chilonis on 250 Gy irradiated and unirradiated fresh eggs of cotton bollworm, Helicoverpa armigera, were not significantly different. The parasitization rate on irradiated chill-stored eggs of H. armigera was lower than that on irradiated fresh eggs. The parasitization rates on eggs from 250 Gy irradiated H. armigera moths depended on their embryonated rates

  14. Survival and reproductive capacity of the tobacco budworm, heliothis virescens (lepidoptera:noctuidae), irradiated as diapausing and young nondiapausing pupae

    International Nuclear Information System (INIS)

    Proshold, F.I.; North, D.T.

    1978-01-01

    Pupal survival, mating, and sperm transfer in tobacco budworm, Heliothis virescens (F.), irradiated as diapause pupae, decreased proportionately with increasing doses of 3, 5, and 7.5 krad. Also, the fertility of tobacco budworms irradiated as nondiapause pupae and of the F 1 progeny of such males decreased with increasing dose. When the female partner received eupyrene sperm, insects irradiated while the pupae were in diapause were fertile as were their progeny. Therefore, it does not appear plausible to irradiate diapause pupae of our strain of tobacco budworms to obtain sterile insects for a release program. (author)

  15. Two-dimensional wavelet analysis of spruce budworm host basal area in the Border Lakes landscape

    Science.gov (United States)

    Patrick M. James; Brian R. Sturtevant; Phil Townsend; Pete Wolter; Marie-Josee. Fortin

    2011-01-01

    Increases in the extent and severity of spruce budworm (Choristoneura fumiferana Clem.) outbreaks over the last century are thought to be the result of changes in forest structure due to forest management. A corollary of this hypothesis is that manipulations of forest structure and composition can be used to reduce future forest vulnerability....

  16. Using Black Light to Find Jack-Pine Budworm Egg Masses

    Science.gov (United States)

    Daniel T. Jennings

    1968-01-01

    Jack pine foliage infested with jack-pine budworm egg masses was examined under two kinds of light -- black light and a combination of natural and fluorescent light. Black light significantly increased the accuracy of count but not the efficiency of examination.

  17. Chemical Basis of Host Plant Selection by Eastern Spruce Budworm, Choristoneura fumiferana Clem. (Lepidoptera:Tortricidae)

    Science.gov (United States)

    Robert L. Talerico; Michael Montgomery; [Tech. Coords

    1983-01-01

    The epicuticular waxes from four host plants of the eastern spruce budworm are examined with respect to their influence on the feeding behavior of the sixth-instar larva. Both current and one-year old needles contain stimulating chemicals in their epicuticular wax layer. Some pure fatty acids known to occur in balsam fir wax are stimulatory, and may serve to enhance...

  18. Monitoring western spruce budworm with pheromone- baited sticky traps to predict subsequent defoliation

    Science.gov (United States)

    Christine G. Niwa; David L. Overhulser

    2015-01-01

    A detailed procedure is described for monitoring western spruce budworm with pheromone-baited sticky traps and interpreting the results to predict defoliation the following year. Information provided includes timing of the survey, how to obtain traps and baits, how many traps are needed, trap assembly, field placement of traps, and how to evaluate the catches.

  19. Stem volume losses in grand firs topkilled by western spruce budworm in Idaho

    Science.gov (United States)

    George T. Ferrell; Robert F. Scharpf

    1982-01-01

    Mature grand firs (Abies grandis [Dougl. ex D. Don] Lindl.) were sampled in two stands, one cutover and one virgin, in the Little Salmon River drainage in west-central Idaho, to estimate stem volume losses associated with topkilling. Damage to the stands resulted from three outbreaks of western spruce budworm (Choristoneura occidentalis...

  20. User's guide to the weather model: a component of the western spruce budworm modeling system.

    Science.gov (United States)

    W. P. Kemp; N. L. Crookston; P. W. Thomas

    1989-01-01

    A stochastic model useful in simulating daily maximum and minimum temperature and precipitation developed by Bruhn and others has been adapted for use in the western spruce budworm modeling system. This document describes how to use the weather model and illustrates some aspects of its behavior.

  1. Effects of a western spruce budworm outbreak on private lands in eastern Oregon, 1980-1994.

    Science.gov (United States)

    David L. Azuma; David L. Overhulser

    2008-01-01

    Forest Inventory and Analysis data from three inventory periods were used to examine the effects of a western spruce budworm outbreak on private lands in eastern Oregon. Growth was negatively related to defoliation with differences between crown ratio and species. The mortality and salvage harvesting caused changes in stand structure on private lands. Although many...

  2. Non-spray spruce budworm management alternatives: Will thinning second-growth balsam fir in northwestern Ontario alter the stands` vulnerability to spruce budworm damage. NWOFTDU technical report No. 53

    Energy Technology Data Exchange (ETDEWEB)

    Van Schip, W.M.; Towill, W.D.; Zago, T.

    1990-12-31

    The objective of this study was to determine whether balsam fir stands, thinned to different levels of basal area, differ in their susceptibility and vulnerability to damage created by infestations of spruce budworm. In 1976-77, the investigators thinned two relatively pure, juvenile, second-growth balsam fir stands in northwestern Ontario to four levels of basal area by girdling or felling. The stands were assessed in 1988. Annual aerial and ground monitoring of the study sites indicated that one area experienced a moderate to severe defoliation by spruce budworm during 1984-86, while the other area experienced moderate to severe defoliation by budworm during 1980-86. This report presents results of the study and discusses the relation between thinning, budworm damage, and stand productivity.

  3. 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

  4. Interactions between Bacillus thuringiensis and parasitoids of late-instar larvae of the spruce budworm (Lepidoptera: Tortricidae)

    NARCIS (Netherlands)

    Schoenmaker, A.; Cusson, M.; Frankenhuyzen, van K.

    2001-01-01

    We investigated interactions between Bacillus thuringiensis Berliner var. kurstaki and parasitoids that attack late instars of the eastern spruce budworm, Choristoneura fumiferana (Clemens). In a petri-dish arena, females of Tranosema rostrale rostrale (Brishke) (Hymenoptera: Ichneumonidae) were

  5. 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.

  6. Long-distance dispersal of spruce budworm (Choristoneura fumiferana Clemens) in Minnesota (USA) and Ontario (Canada) via the atmospheric pathway

    Science.gov (United States)

    Brian R. Sturtevant; Gary L. Achtemeier; Joseph J. Charney; Dean P. Anderson; Barry J. Cooke; Phillip A. Townsend

    2013-01-01

    Dispersal can play an important role in the population dynamics of forest insects, but the role of long-distance immigration and emigration remains unclear due to the difficulty of quantifying dispersal distance and direction. We designed an agent-based spruce budworm flight behavior model that, when interfaced with temperature, wind speed, and precipitation output...

  7. Bollworm responses to release of genetically modified Helicoverpa armigera nucleopolyhedroviruses in cotton

    NARCIS (Netherlands)

    Sun, X.; Chen, X.; Zhang, Z.; Wang, H.; Bianchi, F.J.J.A.; Peng, H.; Vlak, J.M.; Hu, Z.

    2002-01-01

    Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HaSNPV) has been developed as a commercial biopesticide to control the cotton bollworm, H. armigera, in China. The major limitation to a broader application of this virus has been the relative long time to incapacitate the target insect.

  8. Field inactivation of wild-type and genetically modified Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus in cotton

    NARCIS (Netherlands)

    Sun, X.; Sun, X.C.; Werf, van der W.; Vlak, J.M.; Hu, Z.H.

    2004-01-01

    Cotton bollworm (Helicoverpa armigera) is a serious pest on cotton in China. A specific baculovirus, H. armigera nucleopolyhedroviruses (HaSNPV) is used as a commercial biopesticide to control this pest. To improve the pesticidal properties, HaSNPV has been genetically engineered by both deleting

  9. Intraguild interactions and behavior of Spodoptera frugiperda and Helicoverpa spp. on maize.

    Science.gov (United States)

    Bentivenha, José Pf; Montezano, Débora G; Hunt, Thomas E; Baldin, Edson Ll; Peterson, Julie A; Victor, Vinícius S; Pannuti, Luiz Er; Vélez, Ana M; Paula-Moraes, Silvana V

    2017-11-01

    Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is one of the major pests of maize and is in the same feeding guild as the noctuid pests Helicoverpa zea (Boddie) and Helicoverpa armigera (Hübner), recently reported in South and North America. The intraguild interactions of these species were assessed in laboratory and field conditions by determining the survival of larvae in interaction scenarios with non-Bt maize silks and ears. Moreover, a video tracking system was utilized to evaluate behavioral parameters during larval interactions in scenarios with or without food. In intraguild interactions, S. frugiperda had greater survival (55-100%) when competing with Helicoverpa spp. in scenarios where larvae were the same instar or when they were larger (fourth versus second) than their competitor. Frequency and time in food of S. frugiperda larvae were negatively influenced by interactions. Larvae of S. frugiperda moved shorter distances (less than 183.03 cm) compared with H. zea. Overall, S. frugiperda had a competitive advantage over Helicoverpa spp. This study provides significant information regarding noctuid behavior and larval survival during intraguild interactions, which may impact pest prevalence and population dynamics, thereby affecting integrated pest management and insect resistance management of these species in maize. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  10. Identification and characterization of digestive serine proteases from inhibitor-resistant Helicoverpa zea larval midgut

    NARCIS (Netherlands)

    Volpicella, M.; Cordewener, J.H.G.; Jongsma, M.A.; Gallerani, R.; Ceci, L.R.; Beekwilder, M.J.

    2006-01-01

    Protease inhibitors mediate a natural form of plant defence against insects, by interfering with the digestive system of the insect. In this paper, affinity chromatography was used to isolate trypsins and chymotrypsins from Helicoverpa zea larvae, which had been raised on inhibitor-containing diet.

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

    NARCIS (Netherlands)

    Berg, van den 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

  12. Molecular cloning and functional characterization of the diapause hormone receptor in the corn earworm Helicoverpa zea

    Science.gov (United States)

    The diapause hormone (DH) in the heliothine moth has shown its activity in termination of pupal diapause, while the orthology in the silkworm is known to induce embryonic diapause. In the current study, we cloned the diapause hormone receptor from the corn earworm Helicoverpa zea (HzDHr) and tested ...

  13. 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

  14. 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

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

    International Nuclear Information System (INIS)

    Ramos Ocampo, V.; Leon, J.B. de

    2002-01-01

    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 F 1 progeny. However, it lengthened the duration of the larval period by two days. In the F 2 generation, the progeny of the Tf 1 FxTf 1 M 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 P 1 and F 1 female fecundity were recorded. Crosses involving Tf 1 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 P 1 males was greatly affected; fertility in these females was only 61% of that exhibited by the controls. This deleterious effect was inherited in the F 1 and F 2 generations and was maximally expressed when F 1 progeny of the NFxTM cross were inbred. Egg hatch was almost completely inhibited in sibling crosses while outcrosses of the F 1 progeny showed a 64-70% reduction in egg hatch when compared to controls. (author)

  16. The spruce budworm and forest: a qualitative comparison of ODE and Boolean models

    Directory of Open Access Journals (Sweden)

    Raina Robeva

    2016-01-01

    Full Text Available Boolean and polynomial models of biological systems have emerged recently as viable companions to differential equations models. It is not immediately clear however whether such models are capable of capturing the multi-stable behaviour of certain biological systems: this behaviour is often sensitive to changes in the values of the model parameters, while Boolean and polynomial models are qualitative in nature. In the past few years, Boolean models of gene regulatory systems have been shown to capture multi-stability at the molecular level, confirming that such models can be used to obtain information about the system’s qualitative dynamics when precise information regarding its parameters may not be available. In this paper, we examine Boolean approximations of a classical ODE model of budworm outbreaks in a forest and show that these models exhibit a qualitative behaviour consistent with that derived from the ODE models. In particular, we demonstrate that these models can capture the bistable nature of insect population outbreaks, thus showing that Boolean models can be successfully utilized beyond the molecular level.

  17. Rearing Glypta Fumiferanae [hym.:Ichneumonida] on a multivoltine laboratory colony of the Western Spruce Budworm (Choristoneura Occidentalis) [LEP.:Tortricidae

    Science.gov (United States)

    Nancy Rappaport; Marion Page

    1985-01-01

    Methods were devloped for rearing Glypta fumiferanae Viereck on a nondiapausing laboratory colony of the western spruce budworm, Choristoneura occidentalis Freeman. Both host and parasite are univoltine and undergo diapause in nature. In this study, the parasite's voltinism was synchronized with that of a nondiapausing...

  18. Life-history traits maintain the genomic integrity of sympatric species of the spruce budworm (Choristoneura fumiferana) group on an isolated forest island

    Science.gov (United States)

    Lisa M. Lumley; Felix A.H. Sperling

    2011-01-01

    Identification of widespread species collected from islands can be challenging due to the potential for local ecological and phenotypic divergence in isolated populations. We sought to determine how many species of the spruce budworm (Choristoneura fumiferana) complex reside in Cypress Hills, an isolated remnant coniferous forest in western Canada....

  19. Monitoring larval populations of the Douglas-fir tussock moth and the western spruce budworm on permanent plots: sampling methods and statistical properties of data

    Science.gov (United States)

    A.R. Mason; H.G. Paul

    1994-01-01

    Procedures for monitoring larval populations of the Douglas-fir tussock moth and the western spruce budworm are recommended based on many years experience in sampling 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...

  20. The effects of a western spruce budworm outbreak on the dead wood component in relation to ownership in forests of eastern Oregon

    Science.gov (United States)

    David. Azuma

    2010-01-01

    Forest Inventory and Analysis data were used to investigate the effects of a severe western spruce budworm outbreak on the dead wood component of forests in 11 counties of eastern Oregon for two time periods. The ownership and the level of damage (as assessed by aerial surveys) affected the resulting down woody material and standing dead trees. The pattern of coarse...

  1. Effects of gamma irradiation on the sperm transmission and oviposition response in Helicoverpa armigera (L. Noctuidae)

    International Nuclear Information System (INIS)

    Liu Xiaohui; Wang Huasong; Song Jiaxiang

    1999-12-01

    The transmission of sperm by unirradiated and irradiated cotton bollworm, Helicoverpa armigera, was studied by live dissection of the female immediately after the initiation of mating. In cotton bollworm the sperm transfer was a rather complex process. In fact, the unirradiated male failed to transfer sperm in about 19% of their matings. After being irradiated with 250 Gy and 400 Gy, the aberrations of sperm transmission were about 21% and 50% respectively. The failure of spermatophore 'cap' location was an important reason of sperm transmission aberrations. When female mated to high-dose-irradiated males, its oviposition response appeared abnormal

  2. The entomopathogenic fungus Nomuraea rileyi impairs cellular immunity of its host Helicoverpa armigera.

    Science.gov (United States)

    Zhong, Ke; Liu, Zhan-Chi; Wang, Jia-Lin; Liu, Xu-Sheng

    2017-09-01

    In this study, we investigated the effect of the entomopathogenic fungus Nomuraea rileyi on Helicoverpa armigera cellular immune responses. Nomuraea rileyi infection had no effect on total hemocyte count (THC), but impaired hemocyte-mediated phagocytosis, nodulation, and encapsulation responses. Nomuraea rileyi infection led to a significant reduction in hemocyte spreading. An in vitro assay revealed that plasma from N. rileyi infected H. armigera larvae suppressed the spreading ability of hemocytes from naïve larvae. We infer that N. rileyi suppresses the cellular immune response of its host, possibly by secreting exogenous, cytotoxic compounds into the host's hemolymph. © 2017 Wiley Periodicals, Inc.

  3. 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,transmission

  4. A droplet digital PCR (ddPCR) assay to detect Helicoverpa armigera (Lepidoptera: Noctuidae) in bulk trap samples

    Science.gov (United States)

    Moths in the genus Helicoverpa are some of the most important agricultural pests in the world. Two species, H. armigera (Hübner) and H. zea (Boddie), cause the majority of damage to crops and millions of dollars are spent annually on control of these pests. The recent introduction of H. armigera int...

  5. 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

  6. 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

  7. Integrating immunomarking with ecological and behavioural approaches to assess predation of Helicoverpa spp. larvae by wolf spiders in cotton

    Science.gov (United States)

    Wolf spiders (Araneae: Lycosidae) are abundant soil-dwelling predators found in cotton fields and can contribute important pest management services. These spiders can kill and consume larvae of the cotton bollworm Helicoverpa spp. (Lepidoptera: Noctuidae) that survive foraging on Bt cotton and desce...

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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. ED 99 values for inhibition of hatching, pupation, and adult emergence from irradiated eggs were 413, 210, and 154 Gy, respectively. ED 99 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. ED 99 value for inhibition of adult emergence from irradiated pupae was as high as 2310 Gy, whereas that for inhibition of F 1 egg hatching was only 66 Gy. ED 99 value for inhibition of hatching of F 1 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. • ED 99 value for inhibition of pupation and adult emergence of irradiated egg was estimated at 210 and 154 Gy, respectively. • ED 99 value for inhibition of pupation and adult emergence of irradiated larva was estimated at 221 and 167 Gy, respectively

  9. Investigation on mating habit and sexual competition ability of Helicoverpa armigera sterilized by irradiation

    International Nuclear Information System (INIS)

    Xia Darong; Yang Rongxin; Gu Weiping; Zhang Yanjun

    1999-01-01

    Mating habit and sexual competition ability of Helicoverpa armigera irradiated with 300 Gy of γ-rays were observed. The results showed that when reared in laboratory, most adults mated at 4-7 o'clock, a small proportion of adults mated at 2-3 o'clock or at 8-9 o'clock in the morning, meanwhile wild population mated two and a half hours earlier than laboratory populations did. No difference in mating habit and sexual competition ability was found between the irradiation-sterilized and normal adults except that the effective mating rate of the former was 61.6%, one third less than that of the latter ones. Most irradiation-sterilized adults mated one time in their whole lives, only a few could mate 2-3 times and even 5 times, indicating that the multi-mating characteristic of Helicoverpa armigera was not changed by irradiation. It can be concluded that irradiated sterile insect technique is feasible for integrated controlling the cotton bollworm

  10. 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

  11. Two sides of a coin: host-plant synchrony fitness trade-offs in the population dynamics of the western spruce budworm.

    Science.gov (United States)

    Régnière, Jacques; Nealis, Vincent G

    2018-02-01

    Conifer-feeding budworms emerge from overwintering sites as small larvae in early spring, several days before budburst, and mine old needles. These early-emerging larvae suffer considerable mortality during this foraging period as they disperse in search of available, current-year buds. Once buds flush, surviving budworms construct feeding shelters and must complete maturation before fresh host foliage senesces and lignifies later in the summer. Late-developing larvae suffer greater mortality and survivors have lower fecundity when feeding on older foliage. Thus, there is a seasonal trade-off in fitness associated with host synchrony: early-emerging budworms have a greater risk of mortality during spring dispersal but gain better access to the most nutritious foliage, while, on the other hand, late-emerging larvae incur a lower risk during the initial foraging period but must contend with rapidly diminishing resource quality at the end of the feeding period. We investigate the balance that results from these early-season and late-season synchrony fitness trade-offs using the concept of the phenological window. Parameters associated with the variation in the phenological window are used to estimate generational fitness as a function of host-plant synchrony. Because defoliation modifies these relationships, it is also included in the analysis. We show that fitness trade-offs characterizing the phenological window result in a robust synchrony relationship between budworm and host plant over a wide geographic range in southern British Columbia, Canada. © 2016 Her Majesty the Queen in Right of Canada Insect Science © 2016 Institute of Zoology, Chinese Academy of Sciences.

  12. Feeding behaviour of helicoverpa armigera HBN (LEP. noctuidae) on tomatoes in greenhouse

    International Nuclear Information System (INIS)

    Saour, G.; Causse, R.

    1998-01-01

    The feeding behaviour of larvae of Helicoverpa arminegera was studied on tomato plants grown in a greenhouse using 32P -labelled caterpillars. When first larvae emerged from eggs deposited onto usual egg-laying sites, they fed on leaves, occasionally onto Inflorescence, and some burrowed into fruit when they reached the third instars. During the fourth and fifth instar, they fed alternately on leaves and fruit, and occasionally on stems. Toward the end of their development, the caterpillars went through a searching phase to look for a shelter for metamorphosis. This typical sequence could be altered and become more complex in relation with the emerging site of the caterpillars. Green fruits of tomato are usually damaged by larvae of at least 7-8 day old which made several entry holes. These entries were not usually followed by feeding, but they nevertheless damaged an average of 2 ± 0.75 fruits. (author). 13 refs., 4 figs

  13. Performance of Helicoverpa armigera (Hübner (Lepidoptera: Noctuidae larvae in different food sources

    Directory of Open Access Journals (Sweden)

    Crislaine Sartori Suzana

    2015-12-01

    Full Text Available Recently observed in Brazil, Helicoverpa armigera became a relevant pest due to its rapid spread and the economic importance of crops in which it has established, such as soybean and maize. Understanding its establishment process in different regions and production systems, as well as the population dynamics of a polyphagous pest, as the basis for its management, depends on the knowledge of the effect of plant species as food sources on the pest biology. A laboratory experiment was conducted, supplying the caterpillars with reproductive organs of soybean, maize, canola, black oat, oat, turnip and ryegrass. It was concluded that the different food sources affect the larval development of H. armigera. Maize and wheat ears and canola siliques are the best food sources for the development of H. armigera. Ryegrass ears, on the other hand, are the worst ones. Black oat and oat panicles and turnip siliques are less suitable than soybean pods as food sources for the caterpillars.

  14. Effect of Emamectin Benzoate on Mortality, Proboscis Extension, Gustation and Reproduction of the Corn Earworm, Helicoverpa zea

    OpenAIRE

    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 fee...

  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)

    Gauthier, S.

    2004-01-01

    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. Effects of ultraviolet light irradiation on several isozymes in Helicoverpa armigera adults

    International Nuclear Information System (INIS)

    Meng Jianyu; Zhang Changyu; Lei Chaoliang

    2012-01-01

    The effects of ultraviolet (UV)light stress on esterase, peroxidases (POX ), and catalase (CAT) isozymes in Helicoverpa armigera (Hiiber) adults were studied by isozyme eleetrophoresis. When exposed to UV light irradiation, zymogram of esterase isozyme changed mainly in number and activity of isozyme. After 30 min and 60 min exposure, the intensity of isozyme bands E4, E9 and El0 were enhanced, E2 and E8 were weakened. The bands E1, E5, E7 and Ell disappeared after UV light irradiation, while E3 and E6 newly emerged. At the longest exposure time (90 min), the intensity of isozyme bands E4 and E9 was enhanced, while the intensity of E2 and E8 was weakened. The bands E1, E5 and E7 disappeared after UV light irradiation, whereas E3 and E6 newly emerged. The intensity of POX band P5 was enhanced in adults following the exposure to UV light for 30, 60, 90 minutes. The intensity of CAT band C1 was enhanced in adults following the exposure to UV light for 30, 60, 90 minutes, but that of band C2 was weakened after 30 min and 90 min exposure in comparison with the control

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

    Directory of Open Access Journals (Sweden)

    - 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.

  18. Helicoverpa armigera (Lepidoptera: Noctuidae) larvae that survive sublethal doses of nucleopolyhedrovirus exhibit high metabolic rates.

    Science.gov (United States)

    Bouwer, Gustav; Nardini, Luisa; Duncan, Frances D

    2009-04-01

    To determine the effect of sublethal doses of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HearSNPV) on the metabolic rate of H. armigera, the respiration rates of third instar H. armigera larvae inoculated with sublethal doses of HearSNPV were evaluated. Respiration rates, measured as the rate of CO(2) production (VCO(2)), were recorded daily using closed-system respirometry. By 4 days post-inoculation (dpi), the metabolic rates of LD(25) or LD(75) survivors were significantly higher than that of uninoculated controls. When dose data were pooled, the VCO(2) values of larvae that survived inoculation (0.0288mlh(-1)), the uninoculated controls (0.0250mlh(-1)), and the larvae that did not survive inoculation (0.0199mlh(-1)) differed significantly from one another. At 4dpi, the VCO(2) of the uninoculated controls were significantly lower than the VCO(2) of inoculation survivors, but significantly higher than the VCO(2) of inoculation non-survivors. Inoculation survivors may have had high metabolic rates due to a combination of viral replication, organ damage, and an energy-intensive induced cellular immune response. The high 4dpi metabolic rate of inoculation survivors may reflect an effective immune response and may be seen as the metabolic signature of larvae that are in the process of surviving inoculation with HearSNPV.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Characterization of protein phosphatase 5 from three lepidopteran insects: Helicoverpa armigera, Mythimna separata and Plutella xylostella.

    Directory of Open Access Journals (Sweden)

    Xi'en Chen

    Full Text Available Protein phosphatase 5 (PP5, a unique member of serine/threonine phosphatases, regulates a variety of biological processes. We obtained full-length PP5 cDNAs from three lepidopteran insects, Helicoverpa armigera, Mythimna separata and Plutella xylostella, encoding predicted proteins of 490 (55.98 kDa, 490 (55.82 kDa and 491 (56.07 kDa amino acids, respectively. These sequences shared a high identity with other insect PP5s and contained the TPR (tetratricopeptide repeat domains at N-terminal regions and highly conserved C-terminal catalytic domains. Tissue- and stage-specific expression pattern analyses revealed these three PP5 genes were constitutively expressed in all stages and in tested tissues with predominant transcription occurring at the egg and adult stages. Activities of Escherichia coli-produced recombinant PP5 proteins could be enhanced by almost 2-fold by a known PP5 activator: arachidonic acid. Kinetic parameters of three recombinant proteins against substrate pNPP were similar both in the absence or presence of arachidonic acid. Protein phosphatases inhibitors, okadaic acid, cantharidin, and endothall strongly impeded the activities of the three recombinant PP5 proteins, as well as exerted an inhibitory effect on crude protein phosphatases extractions from these three insects. In summary, lepidopteran PP5s share similar characteristics and are all sensitive to the protein phosphatases inhibitors. Our results also imply protein phosphatase inhibitors might be used in the management of lepidopteran pests.

  1. Larval Helicoverpa zea Transcriptional, Growth and Behavioral Responses to Nicotine and Nicotiana tabacum

    Directory of Open Access Journals (Sweden)

    Linus Gog

    2014-09-01

    Full Text Available The polyphagous feeding habits of the corn earworm, Helicoverpa zea (Boddie, underscore its status as a major agricultural pest with a wide geographic distribution and host plant repertoire. To study the transcriptomic response to toxins in diet, we conducted a microarray analysis of H. zea caterpillars feeding on artificial diet, diet laced with nicotine and Nicotiana tabacum (L. plants. We supplemented our analysis with growth and aversion bioassays. The transcriptome reflects an abundant expression of proteases, chitin, cytochrome P450 and immune-related genes, many of which are shared between the two experimental treatments. However, the tobacco treatment tended to elicit stronger transcriptional responses than nicotine-laced diet. The salivary factor glucose oxidase, known to suppress nicotine induction in the plant, was upregulated by H. zea in response to tobacco but not to nicotine-laced diet. Reduced caterpillar growth rates accompanied the broad regulation of genes associated with growth, such as juvenile hormone epoxide hydrolase. The differential expression of chemosensory proteins, such as odorant binding-protein-2 precursor, as well as the neurotransmitter nicotinic-acetylcholine-receptor subunit 9, highlights candidate genes regulating aversive behavior towards nicotine. We suggest that an observed coincidental rise in cannibalistic behavior and regulation of proteases and protease inhibitors in H. zea larvae signify a compensatory response to induced plant defenses.

  2. 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

    2014-02-26

    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. This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.

  3. Characterization of three novel SINE families with unusual features in Helicoverpa armigera.

    Directory of Open Access Journals (Sweden)

    Jianjun Wang

    Full Text Available Although more than 120 families of short interspersed nuclear elements (SINEs have been isolated from the eukaryotic genomes, little is known about SINEs in insects. Here, we characterize three novel SINEs from the cotton bollworm, Helicoverpa armigera. Two of them, HaSE1 and HaSE2, share similar 5' -structure including a tRNA-related region immediately followed by conserved central domain. The 3' -tail of HaSE1 is significantly similar to that of one LINE retrotransposon element, HaRTE1.1, in H. armigera genome. The 3' -region of HaSE2 showed high identity with one mariner-like element in H. armigera. The third family, termed HaSE3, is a 5S rRNA-derived SINE and shares both body part and 3'-tail with HaSE1, thus may represent the first example of a chimera generated by recombination between 5S rRNA and tRNA-derived SINE in insect species. Further database searches revealed the presence of these SINEs in several other related insect species, but not in the silkworm, Bombyx mori, indicating a relatively narrow distribution of these SINEs in Lepidopterans. Apart from above, we found a copy of HaSE2 in the GenBank EST entry for the cotton aphid, Aphis gossypii, suggesting the occurrence of horizontal transfer.

  4. Characterization of Three Novel SINE Families with Unusual Features in Helicoverpa armigera

    Science.gov (United States)

    Wang, Jianjun; Wang, Aina; Han, Zhaojun; Zhang, Zan; Li, Fei; Li, Xianchun

    2012-01-01

    Although more than 120 families of short interspersed nuclear elements (SINEs) have been isolated from the eukaryotic genomes, little is known about SINEs in insects. Here, we characterize three novel SINEs from the cotton bollworm, Helicoverpa armigera. Two of them, HaSE1 and HaSE2, share similar 5′ -structure including a tRNA-related region immediately followed by conserved central domain. The 3′ -tail of HaSE1 is significantly similar to that of one LINE retrotransposon element, HaRTE1.1, in H. armigera genome. The 3′ -region of HaSE2 showed high identity with one mariner-like element in H. armigera. The third family, termed HaSE3, is a 5S rRNA-derived SINE and shares both body part and 3′-tail with HaSE1, thus may represent the first example of a chimera generated by recombination between 5S rRNA and tRNA-derived SINE in insect species. Further database searches revealed the presence of these SINEs in several other related insect species, but not in the silkworm, Bombyx mori, indicating a relatively narrow distribution of these SINEs in Lepidopterans. Apart from above, we found a copy of HaSE2 in the GenBank EST entry for the cotton aphid, Aphis gossypii, suggesting the occurrence of horizontal transfer. PMID:22319625

  5. SUSCETIBILIDADE DE Helicoverpa armigera Hübner A FORMULADOS À BASE DE Bacillus thuringiensis BERLINER

    Directory of Open Access Journals (Sweden)

    Victor Luiz de Souza Lima

    2017-01-01

    Full Text Available O inseto Helicoverpa armigera recentemente registrado no Brasil é uma das maiores pragas da agricultura mundial. Pode atacar mais de 200 espécies de plantas e possui populações resistentes a diversos inseticidas. A utilização de microrganismos com potencial patogênico contra insetos é uma alternativa aos inseticidas. Essa pesquisa foi realizada com o objetivo de determinar a suscetibilidade de lagartas de H. armigera à produtos formulados à base de Bacillus thuringiensis (Bt Para os experimentos, foram utilizados os produtos comerciais Dipel® e Agree®, os quais tiveram sua concentração ajustada para 108 conídios viáveis ml-1. Essa concentração foi aplicada sobre dieta artificial, a qual foi colocada em uma placa de Petri que continha 10 lagartas de primeiro instar. Foram realizadas cinco repetições para cada produto. As avaliações foram feitas a cada 24h durante sete dias. Os produtos comerciais Dipel® e Agree® causaram, respectivamente, 100% e 94% de mortalidade das lagartas de H. armigera. Esse resultado mostra o potencial de produtos à base de Bt sobre H. armigera.

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Mitochondrial DNA and trade data support multiple origins of Helicoverpa armigera (Lepidoptera, Noctuidae) in Brazil

    Science.gov (United States)

    Tay, Wee Tek; Walsh, Thomas K.; Downes, Sharon; Anderson, Craig; Jermiin, Lars S.; Wong, Thomas K. F.; Piper, Melissa C.; Chang, Ester Silva; Macedo, Isabella Barony; Czepak, Cecilia; Behere, Gajanan T.; Silvie, Pierre; Soria, Miguel F.; Frayssinet, Marie; Gordon, Karl H. J.

    2017-03-01

    The Old World bollworm Helicoverpa armigera is now established in Brazil but efforts to identify incursion origin(s) and pathway(s) have met with limited success due to the patchiness of available data. Using international agricultural/horticultural commodity trade data and mitochondrial DNA (mtDNA) cytochrome oxidase I (COI) and cytochrome b (Cyt b) gene markers, we inferred the origins and incursion pathways into Brazil. We detected 20 mtDNA haplotypes from six Brazilian states, eight of which were new to our 97 global COI-Cyt b haplotype database. Direct sequence matches indicated five Brazilian haplotypes had Asian, African, and European origins. We identified 45 parsimoniously informative sites and multiple substitutions per site within the concatenated (945 bp) nucleotide dataset, implying that probabilistic phylogenetic analysis methods are needed. High diversity and signatures of uniquely shared haplotypes with diverse localities combined with the trade data suggested multiple incursions and introduction origins in Brazil. Increasing agricultural/horticultural trade activities between the Old and New Worlds represents a significant biosecurity risk factor. Identifying pest origins will enable resistance profiling that reflects countries of origin to be included when developing a resistance management strategy, while identifying incursion pathways will improve biosecurity protocols and risk analysis at biosecurity hotspots including national ports.

  8. Radiation induced F1 sterility in Helicoverpa zea (Boddie): Potential for area-wide control

    International Nuclear Information System (INIS)

    Carpenter, J.E.

    1993-01-01

    The potential of using F 1 sterility as a management strategy for the corn earworm (CEW), Helicoverpa zea (Boddie), has been revealed through laboratory and field investigations. A 100 Gy dose of radiation induced deleterious effects in CEWs' which were inherited through several generations. Irradiated, laboratory reared CEWs were competitive with non-irradiated, laboratory reared CEWs in attracting and securing mates under field conditions. Females that mated to non-irradiated males and males irradiated with 100 Gy had the same mating propensity and the same intermating interval. Although there was a difference in mortality between larvae from irradiated and non-irradiated parents when reared in the laboratory, this mortality differential was reduced when larvae were reared under natural conditions in the field. Other studies revealed that there was no interaction between inherited sterility and diapause in CEWs when depth of pupation, initiation and termination of diapause, egg hatch, fecundity or survival were investigated. A pilot test that investigated the efficacy of using inherited sterility for suppressing seasonal population increases of CEWs was conducted from 1988 to 1990. Results of the pilot test revealed that irradiated (100 Gy) males released in mountain valleys were competitive with wild males in infusing their genes into the wild population. Analysis of seasonal population curves of wild CEW males calculated from mark-recapture data suggested that seasonal increases in wild CEW males were delayed or reduced in valleys where irradiated males were released. (author). 19 refs, 3 figs

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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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.

  11. Trans-generational desensitization and within-generational resensitization of a sucrose-best neuron in the polyphagous herbivore Helicoverpa armigera (Lepidoptera: Noctuidae)

    NARCIS (Netherlands)

    Ma, Ying; Li, Jingjing; Tang, Qingbo; Zhang, Xuening; Zhao, Xincheng; Yan, Fengming; Loon, van Joop J.A.

    2016-01-01

    Dietary exposure of insects to a feeding deterrent substance for hours to days can induce habituation and concomitant desensitization of the response of peripheral gustatory neurons to such a substance. In the present study, larvae of the herbivore Helicoverpa armigera were fed on diets

  12. Genomic innovations, transcriptional plasticity and gene loss underlying the evolution and divergence of two highly polyphagous and invasive Helicoverpa pest species

    DEFF Research Database (Denmark)

    Pearce, S L; Clarke, D F; East, P D

    2017-01-01

    BACKGROUND: Helicoverpa armigera and Helicoverpa zea are major caterpillar pests of Old and New World agriculture, respectively. Both, particularly H. armigera, are extremely polyphagous, and H. armigera has developed resistance to many insecticides. Here we use comparative genomics, transcriptom......BACKGROUND: Helicoverpa armigera and Helicoverpa zea are major caterpillar pests of Old and New World agriculture, respectively. Both, particularly H. armigera, are extremely polyphagous, and H. armigera has developed resistance to many insecticides. Here we use comparative genomics......, transcriptomics and resequencing to elucidate the genetic basis for their properties as pests. RESULTS: We find that, prior to their divergence about 1.5 Mya, the H. armigera/H. zea lineage had accumulated up to more than 100 more members of specific detoxification and digestion gene families and more than 100...... lacks certain genes and alleles conferring insecticide resistance found in H. armigera. Non-synonymous sites in the expanded gene families above are rapidly diverging, both between paralogues and between orthologues in the two species. Whole genome transcriptomic analyses of H. armigera larvae show...

  13. Diapause hormone in the corn earworm, Helicoverpa zea: Optimum temperature for activity, structure–activity relationships, and efficacy in accelerating flesh fly pupariation

    Czech Academy of Sciences Publication Activity Database

    Zhang, Q.; Žďárek, Jan; Nachman, R. J.; Denlinger, D. L.

    2008-01-01

    Roč. 29, č. 2 (2008), s. 196-205 ISSN 0196-9781 Institutional research plan: CEZ:AV0Z40550506 Keywords : diapause hormone * neuropeptide analogs * diapause termination * pupariation * Helicoverpa zea Subject RIV: CC - Organic Chemistry Impact factor: 2.565, year: 2008

  14. Development, survival and fitness performance of Helicoverpa zea (Lepidoptera: Noctuidae) in MON810 Bt field corn.

    Science.gov (United States)

    Horner, T A; Dively, G P; Herbert, D A

    2003-06-01

    Helicoverpa zea (Boddie) development, survival, and feeding injury in MON810 transgenic ears of field corn (Zea mays L.) expressing Bacillus thuringiensis variety kurstaki (Bt) Cry1Ab endotoxins were compared with non-Bt ears at four geographic locations over two growing seasons. Expression of Cry1Ab endotoxin resulted in overall reductions in the percentage of damaged ears by 33% and in the amount of kernels consumed by 60%. Bt-induced effects varied significantly among locations, partly because of the overall level and timing of H. zea infestations, condition of silk tissue at the time of egg hatch, and the possible effects of plant stress. Larvae feeding on Bt ears produced scattered, discontinuous patches of partially consumed kernels, which were arranged more linearly than the compact feeding patterns in non-Bt ears. The feeding patterns suggest that larvae in Bt ears are moving about sampling kernels more frequently than larvae in non-Bt ears. Because not all kernels express the same level of endotoxin, the spatial heterogeneity of toxin distribution within Bt ears may provide an opportunity for development of behavioral responses in H. zea to avoid toxin. MON810 corn suppressed the establishment and development of H. zea to late instars by at least 75%. This level of control is considered a moderate dose, which may increase the risk of resistance development in areas where MON810 corn is widely adopted and H. zea overwinters successfully. Sublethal effects of MON810 corn resulted in prolonged larval and prepupal development, smaller pupae, and reduced fecundity of H. zea. The moderate dose effects and the spatial heterogeneity of toxin distribution among kernels could increase the additive genetic variance for both physiological and behavioral resistance in H. zea populations. Implications of localized population suppression are discussed.

  15. Baseline Susceptibility of Helicoverpa armigera (Lepidoptera: Noctuidae) to Indoxacarb, Emamectin Benzoate, and Chlorantraniliprole in Australia.

    Science.gov (United States)

    Bird, Lisa J

    2015-02-01

    Baseline susceptibility of Helicoverpa armigera (Hübner) to emamectin benzoate, chlorantraniliprole, and indoxacarb was determined in feeding assays on insecticide-incorporated artificial diet in the laboratory. The intraspecific variation of H. armigera was established from field populations collected between September 2012 and March 2013, primarily from commercial farms across eastern Australia. Emamectin benzoate had the highest toxicity with a median lethal concentration (LC50) of 0.01 µg/ml diet (n=20 strains). The LC50 for chlorantraniliprole was 0.03 µg/ml diet (n=21 strains), while indoxacarb had the lowest relative toxicity with an average LC50 of 0.3 µg/ml diet (n=22 strains). Variation in susceptibility amongst field strains was 2.3-fold for emamectin benzoate and 2.9-fold for chlorantraniliprole and indoxacarb. Discriminating concentrations of 0.2, 1, and 12 µg of insecticide per milliliter of diet for emamectin benzoate, chlorantraniliprole, and indoxacarb, respectively, were calculated from toxicological data from field H. armigera strains as a first step in resistance management of these classes of insecticide in Australia. The low intraspecific tolerance, high slope values, and goodness-of-fit to a probit binomial model obtained in this study suggest that a feeding assay using diet incorporated insecticide is an effective laboratory method for measuring the dose-responses of these classes of insecticides in H. armigera. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. 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. This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.

  17. Activity of Selected Formulated Biorational and Synthetic Insecticides Against Larvae of Helicoverpa armigera (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Vivan, L M; Torres, J B; Fernandes, P L S

    2017-02-01

    This work studied 17 insecticides belonging to nucleopolyhedrovirus (NPV), Bacillus thuringiensis (Bt kurstaki and Bt aizawai), benzoylureas (insect growth regulators [IGRs]), carbamates, organophosphates, spinosyns, and diamides against larvae of Helicoverpa armigera (Hübner), invasive species in the South American continent. Larvae of different instars were fed for 7 d with untreated or insecticide-treated diets. Mortality was recorded daily for 7 d, and surviving larvae were individually weighed on the seventh day. The NPV and Bt insecticides caused 100% mortality of first-instar larvae and first-instar and second-instar larvae, respectively. However, both NPV and Bt-based products caused low mortality of third-instar larvae and did not kill older larvae. The IGR lufenuron was highly effective against all three ages of larvae tested, whereas teflubenzuron and triflumuron produced maximum 60% mortality of second-instar larvae and lower than 50% to older larvae. Thiodicarb, chlorantraniliprole, indoxacarb, chlorpyrifos, and chlorfenapyr, irrespective of tested age, caused 100% mortality of larvae, with the last two insecticides reaching 100% mortality within 2 d of feeding on the treated diet. Flubendiamide caused lower mortality but significantly affected the weight of surviving larvae, whereas neither spinosad nor methomyl produced significant mortality or affected the weight of larvae. Based on the results, the age of H. armigera larvae plays an important role in the recommendation of NPV and Bt insecticides. Furthermore, there are potential options between biological and synthetic insecticides tested against H. armigera, and recording larval size during monitoring, in addition to the infestation level, should be considered when recommending biological-based insecticides to control this pest. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Effects of Helicoverpa armigera (Noctuidae, Lepidoptera) host stages on some developmental parameters of the uniparental endoparasitoid Meteorus pulchricornis (Braconidae, Hymenoptera).

    Science.gov (United States)

    Liu, Ya-Hui; Li, Bao-Ping

    2008-04-01

    A single choice test was performed to examine developmental strategies in the uniparental endoparasitoid Meteorus pulchricornis and its host, the cotton bollworm Helicoverpa armigera. The results support the dome-shaped model in which the fitness functions are 'dome-shaped' relative to size (and age) of host at parasitism. Older and, hence, larger host larvae were simply not better hosts for the developing parasitoids. Although parasitoid size (measured as cocoon weight and adult hind tibia length) was positively correlated with host instars at parasitism, parasitoids developing in larger hosts (L5 and L6) suffered much higher mortality than conspecifics developing in smaller hosts (L2-L4). Furthermore, egg-to-adult development time in M. pulchricornis was significantly longer in older host larvae (L4-L6) than in the younger. Performance of M. pulchricornis, as indicated by fitness-related traits, strongly suggests that the L3 host is the most suitable for survival, growth and development of the parasitoid, followed by both L2 and L4 hosts; whereas, L1, L5 and L6 are the least favourable hosts. The oviposition tendency of M. pulchricornis, represented by parasitism level, was not perfectly consistent with the performance of the offspring; L2-L4 hosts, although with the same parasitism level, had offspring parasitoids with differences in fitness-related performance. Larval development in Helicoverpa armigera was usually suspended, but occasionally advanced, in the final instar.

  19. Cantharidin Impedes Activity of Glutathione S-Transferase in the Midgut of Helicoverpa armigera Hübner

    Directory of Open Access Journals (Sweden)

    Ya Lin Zhang

    2013-03-01

    Full Text Available Previous investigations have implicated glutathione S-transferases (GSTs as one of the major reasons for insecticide resistance. Therefore, effectiveness of new candidate compounds depends on their ability to inhibit GSTs to prevent metabolic detoxification by insects. Cantharidin, a terpenoid compound of insect origin, has been developed as a bio-pesticide in China, and proves highly toxic to a wide range of insects, especially lepidopteran. In the present study, we test cantharidin as a model compound for its toxicity, effects on the mRNA transcription of a model Helicoverpa armigera glutathione S-transferase gene (HaGST and also for its putative inhibitory effect on the catalytic activity of GSTs, both in vivo and in vitro in Helicoverpa armigera, employing molecular and biochemical methods. Bioassay results showed that cantharidin was highly toxic to H. armigera. Real-time qPCR showed down-regulation of the HaGST at the mRNA transcript ranging from 2.5 to 12.5 folds while biochemical assays showed in vivo inhibition of GSTs in midgut and in vitro inhibition of rHaGST. Binding of cantharidin to HaGST was rationalized by homology and molecular docking simulations using a model GST (1PN9 as a template structure. Molecular docking simulations also confirmed accurate docking of the cantharidin molecule to the active site of HaGST impeding its catalytic activity.

  20. Genomic sequencing and analyses of HearMNPV—a new Multinucleocapsid nucleopolyhedrovirus isolated from Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Tang Ping

    2012-08-01

    Full Text Available Abstract Background HearMNPV, a nucleopolyhedrovirus (NPV, which infects the cotton bollworm, Helicoverpa armigera, comprises multiple rod-shaped nucleocapsids in virion(as detected by electron microscopy. HearMNPV shows a different host range compared with H. armigera single-nucleocapsid NPV (HearSNPV. To better understand HearMNPV, the HearMNPV genome was sequenced and analyzed. Methods The morphology of HearMNPV was observed by electron microscope. The qPCR was used to determine the replication kinetics of HearMNPV infectious for H. armigera in vivo. A random genomic library of HearMNPV was constructed according to the “partial filling-in” method, the sequence and organization of the HearMNPV genome was analyzed and compared with sequence data from other baculoviruses. Results Real time qPCR showed that HearMNPV DNA replication included a decreasing phase, latent phase, exponential phase, and a stationary phase during infection of H. armigera. The HearMNPV genome consists of 154,196 base pairs, with a G + C content of 40.07%. 162 putative ORFs were detected in the HearMNPV genome, which represented 90.16% of the genome. The remaining 9.84% constitute four homologous regions and other non-coding regions. The gene content and gene arrangement in HearMNPV were most similar to those of Mamestra configurata NPV-B (MacoNPV-B, but was different to HearSNPV. Comparison of the genome of HearMNPV and MacoNPV-B suggested that HearMNPV has a deletion of a 5.4-kb fragment containing five ORFs. In addition, HearMNPV orf66, bro genes, and hrs are different to the corresponding parts of the MacoNPV-B genome. Conclusions HearMNPV can replicate in vivo in H. armigera and in vitro, and is a new NPV isolate distinguished from HearSNPV. HearMNPV is most closely related to MacoNPV-B, but has a distinct genomic structure, content, and organization.

  1. Comparative analysis of the protein compositions between wild type and body color mutant of helicoverpa armigera adult

    International Nuclear Information System (INIS)

    He Lihua; Chen Jin'e; Liu Yan; Wang Yongqiang; Liu Peigang; Meng Zhiqi

    2012-01-01

    To gain an in-depth understanding of the fineness and regulation mechanism of body color mutant of Helicoverpa armigera Hbner, the protein composition differences between adult of dominant mutant, recessive mutant and wild type were studied using the SDS-PAGE combined with MALDI-TOF-TOF/MS and bioinformatics analysis. The results indicated that the protein composition of the dominant mutant and wild type had little difference. However, there were obvious differences between the recessive mutant and wild-type. Three specific stripe were chosen for mass spectrometry and bioinformatics analysis, and two types of proteins related to energy metabolism and cytoskeleton were identified. These findings suggested that the two types of proteins may be associated with occurrence and regulation of body color mutant traits of H. armigera. (authors)

  2. Interaction of plant cell signaling molecules, salicylic acid and jasmonic acid, with the mitochondria of Helicoverpa armigera.

    Science.gov (United States)

    Akbar, S M D; Sharma, H C; Jayalakshmi, S K; Sreeramulu, K

    2012-02-01

    The cotton bollworm, Helicoverpa armigera is a polyphagous pest in Asia, Africa, and the Mediterranean Europe. Salicylic acid (SA) and jasmonic acid (JA) are the cell signaling molecules produced in response to insect attack in plants. The effect of these signaling molecules was investigated on the oxidative phosphorylation and oxidative stress of H. armigera. SA significantly inhibited the state III and state IV respiration, respiratory control index (RCI), respiratory complexes I and II, induced mitochondrial swelling, and cytochrome c release in vitro. Under in vivo conditions, SA induced state IV respiration as well as oxidative stress in time- and dose-dependent manner, and also inhibited the larval growth. In contrast, JA did not affect the mitochondrial respiration and oxidative stress. SA affected the growth and development of H. armigera, in addition to its function as signaling molecules involved in both local defense reactions at feeding sites and the induction of systemic acquired resistance in plants.

  3. Radiation Induced F-1 Sterility For The Control Of Cotton Bollworm , Helicoverpa armigera (Huebner) In Pilot Test

    International Nuclear Information System (INIS)

    Segsarnviriya, Suchada; Pransopon, Prapon; Kongratarpon, Titima; Vongcheeree, Satit

    2005-10-01

    Pilot trials of radiation induced F-1 sterility for the control of cotton bollworm Helicoverpa armigera (Hubner) were studied for 3 cotton crop seasons in 3 locations at Amphor Takfa, Nakornsawan province in 2002, 2003 and 2004. Irradiated male pupae at a sub sterilizing dose of 150 Gy were released : approximately 11,170 42,900 and 36,400 pupae from July to December of 2002, 2003 and 2004, respectively. The insecticide plots were maintained as a comparison to determine the efficiency of this method. Checking of larvae on cotton plants by the systematic random sampling method and the cotton yield were used to evaluate the impact of the pupal release. It was found that the releasing plots and the insecticide plots gave similar results in terms of the number of larvae and the cotton yield. Therefore, the F-1 sterility method was a possible method for the control of cotton bollworm

  4. 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.

  5. Trans-generational desensitization and within-generational resensitization of a sucrose-best neuron in the polyphagous herbivore Helicoverpa armigera (Lepidoptera: Noctuidae)

    OpenAIRE

    Ying Ma; Jingjing Li; Qingbo Tang; Xuening Zhang; Xincheng Zhao; Fengming Yan; Joop J. A. van Loon

    2016-01-01

    Dietary exposure of insects to a feeding deterrent substance for hours to days can induce habituation and concomitant desensitization of the response of peripheral gustatory neurons to such a substance. In the present study, larvae of the herbivore Helicoverpa armigera were fed on diets containing either a high, medium or low concentration of sucrose, a major feeding stimulant. The responsiveness of the sucrose-best neuron in the lateral sensilla styloconica on the galea was quantified. Resul...

  6. 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

  7. 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

  8. 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.

  9. 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.

  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. Induced resistance to Helicoverpa armigera through exogenous application of jasmonic acid and salicylic acid in groundnut, Arachis hypogaea.

    Science.gov (United States)

    War, Abdul Rashid; Paulraj, Michael Gabriel; Ignacimuthu, Savarimuthu; Sharma, Hari Chand

    2015-01-01

    Induced resistance to Helicoverpa armigera through exogenous application of jasmonic acid (JA) and salicylic acid (SA) was studied in groundnut genotypes (ICGV 86699, ICGV 86031, ICG 2271 and ICG 1697) with different levels of resistance to insects and the susceptible check JL 24 under greenhouse conditions. Activities of oxidative enzymes and the amounts of secondary metabolites and proteins were quantified at 6 days after JA and SA application/insect infestation. Data were also recorded on plant damage and H. armigera larval weights and survival. Higher levels of enzymatic activities and amounts of secondary metabolites were observed in the insect-resistant genotypes pretreated with JA and then infested with H. armigera than in JL 24. The insect-resistant genotypes suffered lower insect damage and resulted in poor survival and lower weights of H. armigera larvae than JL 24. In some cases, JA and SA showed similar effects. JA and SA induced the activity of antioxidative enzymes in groundnut plants against H. armigera, and reduced its growth and development. However, induced response to application of JA was greater than to SA, and resulted in reduced plant damage, and larval weights and survival, suggesting that induced resistance can be used as a component of pest management in groundnut. © 2014 Society of Chemical Industry.

  12. The efficacy of Beauveria bassiana, jasmonic acid and chlorantraniliprole on larval populations of Helicoverpa armigera in chickpea crop ecosystems.

    Science.gov (United States)

    Younas, Aneela; Wakil, Waqas; Khan, Zaeema; Shaaban, Muhammad; Prager, Sean Michael

    2017-02-01

    A robust integrated pest management (IPM) programme is needed to reduce the use of insecticides in controlling Helicoverpa armigera. Therefore, a 2 year field study was conducted to evaluate the use of alternative control measures (biochemical use) for H. armigera relative to exclusively using chemical insecticides. The entomopathogenic fungus Beauveria bassiana, jasmonic acid and the insecticide chlorantraniliprole were each applied twice during the chickpea growing season. All three applied materials (either alone or combined) significantly (P ≤ 0.05) reduced the larval population of H. armigera and pod infestation. Effects increased with time, and the maximum difference was observed 7 days after the second application in each year. The lowest numbers of larvae per plant and pod infestation were in the B. bassiana 3.21 × 10 6 + chlorantraniliprole treatment in both 2009/2010 and 2010/2011 year. The reduction in the larval population and pod infestation increased chickpea yield and the highest yield in both seasons, and the maximum yield was obtained in the B. bassiana 3.21 × 10 6 + chlorantraniliprole treatment. The populations of natural enemies were highest in the jasmonic acid treatment. The results suggest that B. bassiana, jasmonic acid and chlorantraniliprole may be useful components for the H. armigera IPM strategy. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  13. Central projections of gustatory receptor neurons in the medial and the lateral sensilla styloconica of Helicoverpa armigera larvae.

    Directory of Open Access Journals (Sweden)

    Qing-Bo Tang

    Full Text Available Food selection behavior of lepidopteran larvae is predominantly governed by the activation of taste neurons present in two sensilla styloconica located on the galea of the maxilla. In this study, we present the ultrastructure of the sensilla styloconica and the central projection pattern of their associated receptor neurons in larvae of the heliothine moth, Helicoverpa armigera. By means of light microscopy and scanning electron microscopy, the previous findings of two morphologically fairly similar sensilla comprising a socketed conic tip inserted into a large peg were confirmed. However, the peg size of the medial sensillum was found to be significantly bigger than that of the lateral sensillum. The sensory neurons derived from each sensillum styloconicum were mapped separately using anterograde staining experiments combined with confocal laser-scanning microscopy. For determining the afferents' target regions relative to each other, we reconstructed the labeled axons and placed them into a common reference framework. The sensory axons from both sensilla projected via the ipsilateral maxillary nerve to the suboesophageal ganglion and further through the ipsilateral circumoesophageal connective to the brain. In the suboesophageal ganglion, the sensory projections targeted two areas of the ipsilateral maxillary neuropil, one located in the ventrolateral neuromere and the other adjacent to the neuromere midline. In the brain, the axon terminals targeted the dorso-anterior area of the ipsilateral tritocerebrum. As confirmed by the three-dimensional reconstructions, the target regions of the neural projections originating from each of the two sensilla styloconica were identical.

  14. Central projections of gustatory receptor neurons in the medial and the lateral sensilla styloconica of Helicoverpa armigera larvae.

    Science.gov (United States)

    Tang, Qing-Bo; Zhan, Huan; Cao, Huan; Berg, Bente G; Yan, Feng-Ming; Zhao, Xin-Cheng

    2014-01-01

    Food selection behavior of lepidopteran larvae is predominantly governed by the activation of taste neurons present in two sensilla styloconica located on the galea of the maxilla. In this study, we present the ultrastructure of the sensilla styloconica and the central projection pattern of their associated receptor neurons in larvae of the heliothine moth, Helicoverpa armigera. By means of light microscopy and scanning electron microscopy, the previous findings of two morphologically fairly similar sensilla comprising a socketed conic tip inserted into a large peg were confirmed. However, the peg size of the medial sensillum was found to be significantly bigger than that of the lateral sensillum. The sensory neurons derived from each sensillum styloconicum were mapped separately using anterograde staining experiments combined with confocal laser-scanning microscopy. For determining the afferents' target regions relative to each other, we reconstructed the labeled axons and placed them into a common reference framework. The sensory axons from both sensilla projected via the ipsilateral maxillary nerve to the suboesophageal ganglion and further through the ipsilateral circumoesophageal connective to the brain. In the suboesophageal ganglion, the sensory projections targeted two areas of the ipsilateral maxillary neuropil, one located in the ventrolateral neuromere and the other adjacent to the neuromere midline. In the brain, the axon terminals targeted the dorso-anterior area of the ipsilateral tritocerebrum. As confirmed by the three-dimensional reconstructions, the target regions of the neural projections originating from each of the two sensilla styloconica were identical.

  15. 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.

  16. ATIVIDADE DE DETERRÊNCIA ALIMENTAR DO ÓLEO ESSENCIAL DE LARANJA AMARGA SOBRE Helicoverpa armigera HÜBNER

    Directory of Open Access Journals (Sweden)

    Victor Luiz de Souza Lima

    2017-01-01

    Full Text Available Diversas plantas possuem compostos secundários com propriedades inseticidas e o óleo essencial de laranja amarga mostra-se com grande potencial para o controle de pragas. Recentemente, foi registrada no Brasil a espécie Helicoverpa armigera, uma das maiores pragas da agricultura mundial. Tendo em vista a falta de métodos alternativos aos inseticidas para o controle dessa praga, o objetivo desse trabalho foi avaliar os efeitos do óleo essencial de laranja amarga sobre H. armigera. Foi realizado um teste de escolha para avaliar a atividade deterrente. Folhas de tomate foram imersas em soluções contendo óleo de laranja amarga em três concentrações (1, 10 e 100 mg L-1. As folhas tratadas com óleo e folhas não tratadas foram oferecidas à lagartas de segunda instar e após 24h foi calculado o índice de deterrência alimentar (IDA. A concentração de 1 mg L-1 apresentou 71% de deterrência alimentar. Porém as concentrações de 10 e 100 mg L-1 causaram fitotoxidez às folhas de tomate, inviabilizando o consumo pelas lagartas e a estimativa do IDA. Novos testes devem ser realizados com concentrações menores para evitar a fitotoxidez.

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

    Science.gov (United States)

    Zhang, Yun-Feng; van Loon, Joop J A; Wang, Chen-Zhu

    2010-08-15

    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 amino acids. In electrophysiological recordings from nine sensilla, responses were obtained to certain compounds tested at 100 mmol l(-1), and the response spectra differed from broad to narrow. The four sugars excited the same receptor neuron in sensillum a and sensillum b; sucrose and myo-inositol, sucrose and lysine, myo-inositol and lysine excited two different receptor neurons respectively in sensillum a; fructose and lysine excited two different receptor neurons in sensillum n. Furthermore, the four sugars, myo-inositol and lysine all elicited concentration-dependent electrophysiological responses. These six compounds also induced the proboscis extension reflex (PER) followed by ingestion of the solution when they were applied on the tarsi. Lysine and sucrose caused the strongest electrophysiological responses. However, sucrose had the strongest stimulatory effect on the PER whereas lysine had the weakest. Mixtures of sucrose with the other sugars or with lysine had a similar stimulatory effect on the PER as sucrose alone. The electrophysiological and behavioural responses caused by a range of sucrose concentrations were positively correlated. We conclude that the tarsal gustatory sensilla play an essential role in perceiving sugars available in floral nectar and provide chemosensory information determining feeding behaviour. Tarsal taste-receptor-neuron responses to lysine are implicated in oviposition behaviour.

  18. Characterization of lepidopteran-specific cry1 and cry2 gene harbouring native Bacillus thuringiensis isolates toxic against Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Showkat Ahmad Lone

    2017-09-01

    Full Text Available Bacillus thuringiensis (Bt based biopesticides are feasible alternatives to chemical pesticides. Here, we present the distribution of lepidopteran-specific cry1 and cry2 genes in native B. thuringiensis. Forty four out of 86 colonies were found to harbour crystals by phase contrast microscopy exhibiting a Bt index of 0.51. PCR analysis resulted in the amplification of cry1 in 24 and cry2 in 14 isolates. Twelve of the isolates showed presence of both cry1 and cry2, while 18 isolates did not show presence of either of the genes. Toxicity screening using spore-crystal mixtures against 2nd instar larvae of Helicoverpa armigera revealed that the isolates (50% were either mildly toxic or not toxic (36.36%, and only 13.63% were toxic. The results are interesting, particularly so because the same isolates were previously reported to contain lepidopteran specific vip3A genes also, hence can complement the toxicity of the isolates harbouring vip3A genes.

  19. Transgenic Cotton Plants Expressing the HaHR3 Gene Conferred Enhanced Resistance to Helicoverpa armigera and Improved Cotton Yield.

    Science.gov (United States)

    Han, Qiang; Wang, Zhenzhen; He, Yunxin; Xiong, Yehui; Lv, Shun; Li, Shupeng; Zhang, Zhigang; Qiu, Dewen; Zeng, Hongmei

    2017-08-30

    RNA interference (RNAi) has been developed as an efficient technology. RNAi insect-resistant transgenic plants expressing double-stranded RNA (dsRNA) that is ingested into insects to silence target genes can affect the viability of these pests or even lead to their death. HaHR3 , a molt-regulating transcription factor gene, was previously selected as a target expressed in bacteria and tobacco plants to control Helicoverpa armigera by RNAi technology. In this work, we selected the dsRNA- HaHR3 fragment to silence HaHR3 in cotton bollworm for plant mediated-RNAi research. A total of 19 transgenic cotton lines expressing HaHR3 were successfully cultivated, and seven generated lines were used to perform feeding bioassays. Transgenic cotton plants expressing ds HaHR3 were shown to induce high larval mortality and deformities of pupation and adult eclosion when used to feed the newly hatched larvae, and 3rd and 5th instar larvae of H. armigera . Moreover, HaHR3 transgenic cotton also demonstrated an improved cotton yield when compared with controls.

  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. Characterization of the metabolic transformation of thiamethoxam to clothianidin in Helicoverpa armigera larvae by SPE combined UPLC-MS/MS and its relationship with the toxicity of thiamethoxam to Helicoverpa armigera larvae.

    Science.gov (United States)

    Fan, Yinjun; Shi, Xueyan

    2017-09-01

    In order to characterize the metabolic transformation of thiamethoxam (TMX) to clothianidin (CLO) in Helicoverpa armigera larvae and clarify its relationship with the insecticidal toxicity of TMX, method for determination of TMX and its metabolite clothianidin (CLO) residues in H. armigera larvae by solid phase extraction (SPE) combined UPLC-MS/MS was established. Following acetonitrile extraction and purification by SPE on florisil cartridge and C 18 cartridge sequently, and cleanup by PSA adsorption, TMX and CLO residues in H. armigera larvae were successfully determined by UPLC-MS/MS. By using the established method, the concentration-time curves of TMX and its metabolite CLO in H. armigera larvae in vivo and metabolism of TMX by microsome of H. armigera larvae midguts in vitro were studied. TMX was quickly eliminated from H. armigera larvae with the elimination half-life as 4.2h. Meanwhile, only a small amount of CLO was formed from TMX metabolism, with the maximum CLO level in H. armigera larvae only accounts for the metabolic transformation of 7.99% of TMX, at 10h after intravenous TMX administration. Our results suggested that the low insecticidal efficacy of TMX against H. armigera larvae was related with the rapidly elimination of TMX from H. armigera larvae, meanwhile, CLO as TMX metabolite at a very low level in vivo didn't contribute to TMX toxicity to H. armigera larvae. In H. armigera larvae, TMX didn't act as proinsecticide for CLO in insecticidal efficacy of TMX. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Field evolved resistance in Helicoverpa armigera (Lepidoptera: Noctuidae to Bacillus thuringiensis toxin Cry1Ac in Pakistan.

    Directory of Open Access Journals (Sweden)

    Anwaar H K Alvi

    Full Text Available Helicoverpa armigera (Hübner is one of the most destructive pests of several field and vegetable crops, with indiscriminate use of insecticides contributing to multiple instances of resistance. In the present study we assessed whether H. armigera had developed resistance to Bt cotton and compared the results with several conventional insecticides. Furthermore, the genetics of resistance was also investigated to determine the inheritance to Cry1Ac resistance. To investigate the development of resistance to Bt cotton, and selected foliar insecticides, H. armigera populations were sampled in 2010 and 2011 in several cotton production regions in Pakistan. The resistance ratios (RR for Cry1Ac, chlorpyrifos, profenofos, cypermethrin, spinosad, indoxacarb, abamectin and deltamethrin were 580-fold, 320-, 1110-, 1950-, 200-, 380, 690, and 40-fold, respectively, compared with the laboratory susceptible (Lab-PK population. Selection of the field collected population with Cry1Ac in 2010 for five generations increased RR to 5440-fold. The selection also increased RR for deltamethrin, chlorpyrifos, profenofos, cypermethrin, spinosad, indoxacarb, abamectin to 125-folds, 650-, 2840-, 9830-, 370-, 3090-, 1330-fold. The estimated LC(50s for reciprocal crosses were 105 µg/ml (Cry1Ac-SEL female × Lab-PK male and 81 g µg/ml (Lab-PK female × Cry1Ac-SEL male suggesting that the resistance to Cry1Ac was autosomal; the degree of dominance (D(LC was 0.60 and 0.57 respectively. Mixing of enzyme inhibitors significantly decreased resistance to Cry1Ac suggesting that the resistance to Cry1Ac and other insecticides tested in the present study was primarily metabolic. Resistance to Cry1Ac was probably due to a single but unstable factor suggesting that crop rotation with non-Bt cotton or other crops could reduce the selection pressure for H. armigera and improve the sustainability of Bt cotton.

  3. 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. © 2014 Institute of Zoology, Chinese Academy of Sciences.

  4. Gamma radiation for all phases of life cycle of cotton bollworm Helicoverpa armigera aiming at its control

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, Gianni Q.; Arthur, Valter, E-mail: ghaddad2001@yahoo.com.br, E-mail: arthur@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Laboratório de Radiobiologia e Ambiente; Machi, André R., E-mail: rica_machi@hotmail.com [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    Since the 1950s, scientists have used ionizing radiation to sterilize insects, which are released in nature to mate, but without any progeny. Known as the sterile insect technique (SIT), this insect control method traditionally uses ionizing radiations to sterilize insects, being a technique that does not generate residue, and can act in synergy with the other techniques within integrated pest management. For several years, Brazil has been fighting against the increase of pests, introducing new tactics and techniques within IPM programs, to overcome the resistance of chemical products, such as: reducing residues of pesticides. For some important crops of our country, we have a wide spectrum of pests occurring from beginning to end of the harvest, one of them is the cotton crop and among the key pests of this crop, we have some extremely important caterpillars among them Helicoverpa armigera. Due to this the objective this study was establishes doses of gamma radiation to sterilizing of the phases of : eggs, larvae, pupae and adults of H. armigera aiming their control. The experiment was carried out with application of gamma radiation from a Cobalt-60 source. The treatments consisted of doses of gamma radiation varying of according with the insect phase, being this variation of: 0 (control) to 400 Gy. The experiments with pupae and adult phases showed satisfactory results in the sterilization of H. armigera for use in autocide control programs. The sterilize dose to adult and pupae phase were 400 Gy and 100 Gy respectively, being the best doses for the application of the sterile insect technique to this pest in cotton. (author)

  5. 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. Published by Oxford University Press on behalf of the Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

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

    Directory of Open Access Journals (Sweden)

    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.

  7. 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

  8. Acute, sublethal and combination effects of azadirachtin and Bacillus thuringiensis toxins on Helicoverpa armigera (Lepidoptera: Noctuidae) larvae.

    Science.gov (United States)

    Singh, G; Rup, P J; Koul, Opender

    2007-08-01

    The efficacy of neem (1500 ppm azadirachtin (AI)), Delfin WG, a biological insecticide based on selected strain of Bacillus thuringiensis Berliner (Bt) subspecies kurstaki, and Cry1Ac protein, either individually or in combination, were examined against first to fourth instar Helicoverpa armigera (Hübner) larvae. Using an oral administration method, various growth inhibitory concentrations (EC) and lethal concentrations (LC) were determined for each bioagent. Combinations of sublethal concentrations of Bt spray formulation with azadirachtin at EC50 or EC95 levels not only enhanced the toxicity, but also reduced the duration of action when used in a mixture. The LC20 and LC50 values for Cry1Ac toxin were 0.06 and 0.22 microg ml-1, respectively. Bt-azadirachtin combinations of LC50+EC20 and LC50+EC50 result in 100% mortality. The mortality also was significant in LC20+EC20 and LC20+EC50 mixtures. These studies imply that the combined action is not synergistic but complimentary, with azadirachtin particularly facilitating the action of Bt. The Bt spray-azadirachtin combination is more economical than combinations that involve isolating the toxic protein, as the Bt spray formulations can be combined in a spray mixture with neem. These combinations may be useful for controlling bollworm populations that have acquired resistance to Bt as they may not survive the effect of mixture. Azadirachtin may be useful as a means of reducing the endotoxin concentrations in a mixture, to promote increased economic savings and further reduce the probability of resistance development to either insect control agent.

  9. Role of induced glutathione-S-transferase from Helicoverpa armigera (Lepidoptera: Noctuidae) HaGST-8 in detoxification of pesticides.

    Science.gov (United States)

    Labade, Chaitali P; Jadhav, Abhilash R; Ahire, Mehul; Zinjarde, Smita S; Tamhane, Vaijayanti A

    2018-01-01

    The present study deals with glutathione-S-transferase (GST) based detoxification of pesticides in Helicoverpa armigera and its potential application in eliminating pesticides from the environment. Dietary exposure of a pesticide mixture (organophosphates - chlorpyrifos and dichlorvos, pyrethroid - cypermethrin; 2-15ppm each) to H. armigera larvae resulted in a dose dependant up-regulation of GST activity and gene expression. A variant GST from H. armigera (HaGST-8) was isolated from larvae fed with 10ppm pesticide mixture and it was recombinantly expressed in yeast (Pichia pastoris HaGST-8). HaGST-8 had a molecular mass of 29kDa and was most active at pH 9 at 30°C. GC-MS and LC-HRMS analysis validated that HaGST-8 was effective in eliminating organophosphate type of pesticides and partially reduced the cypermethrin content (53%) from aqueous solutions. Unlike the untransformed yeast, P. pastoris HaGST-8 grew efficiently in media supplemented with pesticide mixtures (200 and 400ppm each pesticide) signifying the detoxification ability of HaGST-8. The amino acid sequence of HaGST-8 and the already reported sequence of HaGST-7 had just 2 mismatches. The studies on molecular interaction strengths revealed that HaGST-8 had stronger binding affinities with organophosphate, pyrethroid, organochloride, carbamate and neonicotinoid type of pesticides. The abilities of recombinant HaGST-8 to eliminate pesticides and P. pastoris HaGST-8 to grow profusely in the presence of high level of pesticide content can be applied for removal of such residues from food, water resources and bioremediation. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Gamma radiation for all phases of life cycle of cotton bollworm Helicoverpa armigera aiming at its control

    International Nuclear Information System (INIS)

    Haddad, Gianni Q.; Arthur, Valter

    2017-01-01

    Since the 1950s, scientists have used ionizing radiation to sterilize insects, which are released in nature to mate, but without any progeny. Known as the sterile insect technique (SIT), this insect control method traditionally uses ionizing radiations to sterilize insects, being a technique that does not generate residue, and can act in synergy with the other techniques within integrated pest management. For several years, Brazil has been fighting against the increase of pests, introducing new tactics and techniques within IPM programs, to overcome the resistance of chemical products, such as: reducing residues of pesticides. For some important crops of our country, we have a wide spectrum of pests occurring from beginning to end of the harvest, one of them is the cotton crop and among the key pests of this crop, we have some extremely important caterpillars among them Helicoverpa armigera. Due to this the objective this study was establishes doses of gamma radiation to sterilizing of the phases of : eggs, larvae, pupae and adults of H. armigera aiming their control. The experiment was carried out with application of gamma radiation from a Cobalt-60 source. The treatments consisted of doses of gamma radiation varying of according with the insect phase, being this variation of: 0 (control) to 400 Gy. The experiments with pupae and adult phases showed satisfactory results in the sterilization of H. armigera for use in autocide control programs. The sterilize dose to adult and pupae phase were 400 Gy and 100 Gy respectively, being the best doses for the application of the sterile insect technique to this pest in cotton. (author)

  11. 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

  12. 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)

    Lu Daguang; Liu Xiaohui; Hu Jiangguo; Wang Endong; He Qiulan; Li Yongjun

    2002-01-01

    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)

  13. 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

  14. 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

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

    DEFF Research Database (Denmark)

    Hassanpour, Mehdi; Mohaghegh, Jafar; Iranipour, Shahzad

    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 Hübner. The first and second instar larvae of C. carnea exhibited type II functional responses against both prey stages. However, the third instar larvae of C. carnea showed a type II functional response to the first instar larvae of H. armigera, but a type III 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...

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

    Science.gov (United States)

    Gilligan, Todd M; Tembrock, Luke R; Farris, Roxanne E; Barr, Norman B; van der Straten, Marja J; van de Vossenberg, Bart T L H; Metz-Verschure, Eveline

    2015-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Effects of Soil Salinity on the Expression of Bt Toxin (Cry1Ac and the Control Efficiency of Helicoverpa armigera in Field-Grown Transgenic Bt Cotton.

    Directory of Open Access Journals (Sweden)

    Jun-Yu Luo

    Full Text Available An increasing area of transgenic Bacillus thuringiensis (Bt cotton is being planted in saline-alkaline soil in China. The Bt protein level in transgenic cotton plants and its control efficiency can be affected by abiotic stress, including high temperature, water deficiency and other factors. However, how soil salinity affects the expression of Bt protein, thus influencing the control efficiency of Bt cotton against the cotton bollworm (CBW Helicoverpa armigera (Hübner in the field, is poorly understood. Our objective in the present study was to investigate the effects of soil salinity on the expression of Bt toxin (Cry1Ac and the control efficiency of Helicoverpa armigera in field-grown transgenic Bt cotton using three natural saline levels (1.15 dS m-1 [low soil-salinity], 6.00 dS m-1 [medium soil-salinity] and 11.46 dS m-1 [high soil-salinity]. We found that the Bt protein content in the transgenic Bt cotton leaves and the insecticidal activity of Bt cotton against CBW decreased with the increasing soil salinity in laboratory experiments during the growing season. The Bt protein content of Bt cotton leaves in the laboratory were negatively correlated with the salinity level. The CBW populations were highest on the Bt cotton grown in medium-salinity soil instead of the high-salinity soil in field conditions. A possible mechanism may be that the relatively high-salinity soil changed the plant nutritional quality or other plant defensive traits. The results from this study may help to identify more appropriate practices to control CBW in Bt cotton fields with different soil salinity levels.

  19. Trans-generational desensitization and within-generational resensitization of a sucrose-best neuron in the polyphagous herbivore Helicoverpa armigera (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Ma, Ying; Li, Jingjing; Tang, Qingbo; Zhang, Xuening; Zhao, Xincheng; Yan, Fengming; van Loon, Joop J A

    2016-12-14

    Dietary exposure of insects to a feeding deterrent substance for hours to days can induce habituation and concomitant desensitization of the response of peripheral gustatory neurons to such a substance. In the present study, larvae of the herbivore Helicoverpa armigera were fed on diets containing either a high, medium or low concentration of sucrose, a major feeding stimulant. The responsiveness of the sucrose-best neuron in the lateral sensilla styloconica on the galea was quantified. Results showed the response of the sucrose-best neuron exposed to high-sucrose diets decreased gradually over successive generations, resulting in complete desensitization in the 5 th and subsequent generations. However, the sensitivity was completely restored in the ninth generation after neonate larvae were exposed to low-sucrose diet. These findings demonstrate phenotypic plasticity and exclude inadvertent artificial selection for low sensitivity to sucrose. No significant changes were found in the sensitivity of caterpillars which experienced low- or medium-sucrose diets over the same generations. Such desensitization versus re-sensitization did not generalise to the phagosimulant myo-inositol-sensitive neuron or the feeding deterrent-sensitive neuron. Our results demonstrate that under conditions of high sucrose availability trans-generational desensitization of a neuron sensitive to this feeding stimulant becomes more pronounced whereas re-sensitization occurs within one generation.

  20. Lethal and sublethal effects of cantharidin on the life history traits and population parameters of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Khan, Rashid A; Rashid, Maryam; Wang, Dun; Zhang, Ya-Lin

    2014-01-01

    The cotton bollworm, Helicoverpa armigera (Hübner), is a serious and cosmopolitan pest of many economic crops. Its control has not been adequate owing to its resistance to many groups of insecticides. Toxicity of cantharidin on armyworm and diamondback moth has already been reported. However, its toxicity on H. armigera has not been investigated previously. In this study, lethal and sublethal effects of cantharidin on H. armigera under laboratory conditions are reported. Results showed gross abnormalities in the population parameters of H. armigera, ranging from larvae to adults. Reduction in larval weight and wing malformation were observed in the cantharidin-treated population cohort, and higher mortality at the larval, pupal and adult stages was observed in cantharidin-treated H. armigera compared with the control. Moreover, almost 5 times less fecundity was recorded in the treated population cohort. Fertility was also severely affected, and reduction in all population parameters was observed. Cantharidin caused larval mortality and other serious abnormalities in H. armigera population parameters, and therefore may have positive implications for pest management decision-making process. More interestingly, the experiment revealed that cantharidin in sublethal dose mimicked insect growth regulator insecticides. Furthermore, cantharidin could be used as a precursor compound for the synthesis of new analogues and compounds to replace ineffective older compounds. © 2013 Society of Chemical Industry.

  1. Sorghum Seed Maturity Affects the Weight and Feeding Duration of Immature Corn Earworm, Helicoverpa zea, and Fall Armyworm, Spodoptera frugiperda, in the Laboratory

    Science.gov (United States)

    Soper, Alysha M.; Whitworth, R. Jeff; McCornack, Brian P.

    2013-01-01

    Corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), and fall armyworm, Spodoptera frugiperda J.E. Smith, are occasional pests in sorghum, Sorghum bicolor L. Moench (Poales: Poaceae), and can be economically damaging when conditions are favorable. Despite the frequent occurrence of mixed-species infestations, the quantitative data necessary for developing yield loss relationships for S. frugiperda are not available. Although these species share similar biological characteristics, it is unknown whether their damage potentials in developing grain sorghum panicles are the same. Using no-choice feeding assays in the laboratory, this study examined larval growth and feeding duration for H. zea and S. frugiperda in the absence of competition. Each species responded positively when exposed to sorghum seed in the soft-dough stage, supporting evidence for the interactions between host-quality and larval growth and development. The results of this study also confirmed the suitability of using laboratory-reared H. zea to develop sorghum yield loss estimates in the field, and provided insights into the biological responses of S. frugiperda feeding on developing sorghum seed. PMID:24219328

  2. The Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) voltage-gated sodium channel and mutations associated with pyrethroid resistance in field-collected adult males.

    Science.gov (United States)

    Hopkins, B W; Pietrantonio, P V

    2010-05-01

    Helicoverpa zea is one of the most costly insect pests of food and fiber crops throughout the Americas. Pyrethroid insecticides are widely applied for its control as they are effective and relatively inexpensive; however, resistance to pyrethroids threatens agricultural systems sustainability because alternative insecticides are often more expensive or less effective. Although pyrethroid resistance has been identified in this pest since 1990, the mechanisms of resistance have not yet been elucidated at the molecular level. Pyrethroids exert their toxicity by prolonging the open state of the voltage-gated sodium channel. Here we report the cDNA sequence of the H. zea sodium channel alpha-subunit homologous to the para gene from Drosophila melanogaster. In field-collected males which were resistant to cypermethrin as determined by the adult vial test, we identify known resistance-conferring mutations L1029H and V421M, along with two novel mutations at the V421 residue, V421A and V421G. An additional mutation, I951V, may be the first example of a pyrethroid resistance mutation caused by RNA editing. Identification of the sodium channel cDNA sequence will allow for testing hypotheses on target-site resistance for insecticides acting on this channel through modeling and expression studies. Understanding the mechanisms responsible for resistance will greatly improve our ability to identify and predict resistance, as well as preserve susceptibility to pyrethroid insecticides. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. DETERMINAÇÃO DO NÚMERO DE FÊMEAS VIRGENS POR ARMADILHA E PERIODICIDADE DE CAPTURA DE MACHOS DE Helicoverpa zea (BODDIE (LEPIDOPTERA: NOCTUIDAE

    Directory of Open Access Journals (Sweden)

    MATRANGOLO W.J.R

    1996-01-01

    Full Text Available Avaliou-se em lavouras de milho em fase de liberação de estilo-estigmas, na EMBRAPA/CNPMS, em Sete Lagoas, MG, a atratividade de diferentes números de fêmeas virgens de Helicoverpa zea (Boddie em armadilha adesiva, além de uma formulação comercial do feromônio sintético, proveniente dos E.E.U.U. A maior atividade de procura por acasalamento teve início nas primeiras horas da noite. Não houve diferença significativa entre médias de insetos capturados com uma, três ou cinco fêmeas. Cinco fêmeas por armadilha tornam o monitoramento pouco prático; uma apenas pode comprometer a captura por disfunção fisiológica ou mesmo morte. Não houve captura nas armadilhas contendo feromônio sintético, que, ao invés, capturou machos de Mythimna, outro Noctuidae. A maior freqüência de captura nas armadilhas ocorreu após a meia noite, diminuindo próximo do alvorecer. O horário de início de chamamento e captura esteve estreitamente relacionado com a temperatura ambiente.

  4. Formulation of A Novel Phytopesticide PONNEEM and its Potentiality to control generalist Herbivorous Lepidopteran insect pests, Spodoptera litura (Fabricius and Helicoverpa armigera (H übner (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Susaimanickam Maria Packiam

    2012-10-01

    Full Text Available Objective: To evaluate the deterrence of oviposition potentiality of a novel phytopesticide PONNEEM against the generalist herbivorous lepidopteran insect pests Helicoverpa armigera and Spodoptera litura. Methods: Different phytopesticidal formulations were prepared at different ratio to evaluate the deterrence of oviposition activity against S. litura and H. armigera at 5, 10, 15, and 20毺 L/L concentrations. Results: The newly formulated different phytopesticides exhibited good results of oviposition deterrent activity against these two polyphagous insect pests. At 20毺 L/L concentration of PONNEEM, 77.48% of the maximum deterrence of oviposition activity was recorded, followed by formulation A (49.23%. And 68.12% was observed against H. armigera followed by A (49.52%. PONNEEM exhibited statistically significant oviposition deterrent activity compared to all other treatments. Conclusions: The newly formulated PONNEEM was found to be effective phytopesticidal formulation to control the adult of S. litura and H. armigera due to the synergistic effect of biomolecules such as azadirachtin and karanjin. This is the first report of PONNEEM which was patented under the government of India. The potential use of this novel phytopesticide could be an agent of controlling the adults of lepidopteran insect pests which can be applied in the integrated pest management programme.

  5. Azadirachtin-A and tetrahydroazadirachtin-A concentrates: preparation, LC-MS characterization and insect antifeedant/IGR activity against Helicoverpa armigera (Hübner).

    Science.gov (United States)

    Sharma, Vandana; Walia, Suresh; Dhingra, Swaran; Kumar, Jitendra; Parmar, Balraj S

    2006-10-01

    A 60% azadirachtin-A concentrate has been obtained through repeated precipitation with hexane from a methanolic solution of a 20% concentrate. Azadirachtin-A (90%) has been obtained by medium-pressure liquid chromatography of the 60% concentrate with an RP-18 column and a methanol + water (1 + 1 by volume) solvent system. Catalytic hydrogenation of the 60 and 90% azadirachtin concentrates yielded the corresponding tetrahydroazadirachtin concentrates. Dihydroazadirachtin and tetrahydroazadirachtin formed during the first 5 h of hydrogenation were identified by LC-ESI-MS on the basis of their unique mass fragmentation pattern. The efficacy of tetrahydroazadirachtin concentrates in inhibiting the feeding and growth of Helicoverpa armigera (Hübner) larvae has been compared with that of azadirachtin concentrates. They were in general more active and deterred larvae from feeding at all concentrations. Tetrahydroazadirachtin-A (90%) and azadirachtin-A (90%) with respective IC(50) values of 280 and 390 mg L(-1) were effective as insect growth regulators, while tetrahydroazadirachtin-A (90%) displayed higher antifeedant activity (AI(50) 14 mg L(-1)) against the test insect.

  6. Sorghum seed maturity affects the weight and feeding duration of immature corn earworm, Helicoverpa zea, and fall armyworm, Spodoptera frugiperda, in the laboratory.

    Science.gov (United States)

    Soper, Alysha M; Whitworth, R Jeff; McCornack, Brian P

    2013-01-01

    Corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), and fall armyworm, Spodoptera frugiperda J.E. Smith, are occasional pests in sorghum, Sorghum bicolor L. Moench (Poales: Poaceae), and can be economically damaging when conditions are favorable. Despite the frequent occurrence of mixed-species infestations, the quantitative data necessary for developing yield loss relationships for S. frugiperda are not available. Although these species share similar biological characteristics, it is unknown whether their damage potentials in developing grain sorghum panicles are the same. Using no-choice feeding assays in the laboratory, this study examined larval growth and feeding duration for H. zea and S. frugiperda in the absence of competition. Each species responded positively when exposed to sorghum seed in the soft-dough stage, supporting evidence for the interactions between host-quality and larval growth and development. The results of this study also confirmed the suitability of using laboratory-reared H. zea to develop sorghum yield loss estimates in the field, and provided insights into the biological responses of S. frugiperda feeding on developing sorghum seed.

  7. 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.

  8. No evidence for change in oviposition behaviour of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) after widespread adoption of transgenic insecticidal cotton.

    Science.gov (United States)

    Zalucki, M P; Cunningham, J P; Downes, S; Ward, P; Lange, C; Meissle, M; Schellhorn, N A; Zalucki, J M

    2012-08-01

    Cotton growing landscapes in Australia have been dominated by dual-toxin transgenic Bt varieties since 2004. The cotton crop has thus effectively become a sink for the main target pest, Helicoverpa armigera. Theory predicts that there should be strong selection on female moths to avoid laying on such plants. We assessed oviposition, collected from two cotton-growing regions, by female moths when given a choice of tobacco, cotton and cabbage. Earlier work in the 1980s and 1990s on populations from the same geographic locations indicated these hosts were on average ranked as high, mid and low preference plants, respectively, and that host rankings had a heritable component. In the present study, we found no change in the relative ranking of hosts by females, with most eggs being laid on tobacco, then cotton and least on cabbage. As in earlier work, some females laid most eggs on cotton and aspects of oviposition behaviour had a heritable component. Certainly, cotton is not avoided as a host, and the implications of these finding for managing resistance to Bt cotton are discussed.

  9. Transgenic plants over-expressing insect-specific microRNA acquire insecticidal activity against Helicoverpa armigera: an alternative to Bt-toxin technology.

    Science.gov (United States)

    Agrawal, Aditi; Rajamani, Vijayalakshmi; Reddy, Vanga Siva; Mukherjee, Sunil Kumar; Bhatnagar, Raj K

    2015-10-01

    The success of Bt transgenics in controlling predation of crops has been tempered by sporadic emergence of resistance in targeted insect larvae. Such emerging threats have prompted the search for novel insecticidal molecules that are specific and could be expressed through plants. We have resorted to small RNA-based technology for an investigative search and focused our attention to an insect-specific miRNA that interferes with the insect molting process resulting in the death of the larvae. In this study, we report the designing of a vector that produces artificial microRNA (amiR), namely amiR-24, which targets the chitinase gene of Helicoverpa armigera. This vector was used as transgene in tobacco. Northern blot and real-time analysis revealed the high level expression of amiR-24 in transgenic tobacco plants. Larvae feeding on the transgenic plants ceased to molt further and eventually died. Our results demonstrate that transgenic tobacco plants can express amiR-24 insectice specific to H. armigera.

  10. 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.

  11. 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

  12. Population genetic structure of the cotton bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in India as inferred from EPIC-PCR DNA markers.

    Science.gov (United States)

    Behere, Gajanan Tryambak; Tay, Wee Tek; Russell, Derek Alan; Kranthi, Keshav Raj; Batterham, Philip

    2013-01-01

    Helicoverpa armigera is an important pest of cotton and other agricultural crops in the Old World. Its wide host range, high mobility and fecundity, and the ability to adapt and develop resistance against all common groups of insecticides used for its management have exacerbated its pest status. An understanding of the population genetic structure in H. armigera under Indian agricultural conditions will help ascertain gene flow patterns across different agricultural zones. This study inferred the population genetic structure of Indian H. armigera using five Exon-Primed Intron-Crossing (EPIC)-PCR markers. Nested alternative EPIC markers detected moderate null allele frequencies (4.3% to 9.4%) in loci used to infer population genetic structure but the apparently genome-wide heterozygote deficit suggests in-breeding or a Wahlund effect rather than a null allele effect. Population genetic analysis of the 26 populations suggested significant genetic differentiation within India but especially in cotton-feeding populations in the 2006-07 cropping season. In contrast, overall pair-wise F(ST) estimates from populations feeding on food crops indicated no significant population substructure irrespective of cropping seasons. A Baysian cluster analysis was used to assign the genetic make-up of individuals to likely membership of population clusters. Some evidence was found for four major clusters with individuals in two populations from cotton in one year (from two populations in northern India) showing especially high homogeneity. Taken as a whole, this study found evidence of population substructure at host crop, temporal and spatial levels in Indian H. armigera, without, however, a clear biological rationale for these structures being evident.

  13. The Use of F2 Screening for Detection of Resistance to Emamectin Benzoate, Chlorantraniliprole, and Indoxacarb in Australian Populations of Helicoverpa armigera (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Bird, L J; Drynan, L J; Walker, P W

    2017-04-01

    The ability to effectively detect changes in susceptibility to insecticides is an integral component of resistance management strategies and is highly dependent upon precision of methods deployed. Between 2013 and 2016, F2 screens were performed for detection of resistance alleles in Helicoverpa armigera (Hübner) to emamectin benzoate, chlorantraniliprole, and indoxacarb in major cropping regions of eastern Australia. Resistance to emamectin benzoate was not detected. There were low but detectable levels of survival at discriminating concentrations of chlorantraniliprole and indoxacarb. Alleles conferring an advantage to chlorantraniliprole were present at a frequency of 0.0027 (95% CI 0.0012-0.0064; n = 1,817). Alleles conferring an advantage to indoxacarb were present at a frequency of 0.027 (95% CI 0.020-0.035; n = 1,863). Complementation tests for allelism in six of seven positive indoxacarb tests indicated that resistance was due to alleles present at the same locus. The majority (88%) of lines that tested positive for indoxacarb resistance deviated from a model of recessive inheritance. Pheromone-caught male moths contributed significantly greater numbers of F2 lines compared with moths derived from field-collected eggs or larvae. There was no difference in the detectability of indoxacarb resistance in F2 lines from pheromone-caught moths compared with moths derived from immature stages collected from the field and reared to adult under laboratory conditions. Therefore, we recommend the use of pheromone traps for sourcing insects for F2 screening as a more cost- and time-efficient alternative to traditional methods of sampling. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Characterization of a digestive carboxypeptidase from the insect pest corn earworm (Helicoverpa armigera) with novel specificity towards C-terminal glutamate residues.

    Science.gov (United States)

    Bown, David P; Gatehouse, John A

    2004-05-01

    Carboxypeptidases were purified from guts of larvae of corn earworm (Helicoverpa armigera), a lepidopteran crop pest, by affinity chromatography on immobilized potato carboxypeptidase inhibitor, and characterized by N-terminal sequencing. A larval gut cDNA library was screened using probes based on these protein sequences. cDNA HaCA42 encoded a carboxypeptidase with sequence similarity to enzymes of clan MC [Barrett, A. J., Rawlings, N. D. & Woessner, J. F. (1998) Handbook of Proteolytic Enzymes. Academic Press, London.], but with a novel predicted specificity towards C-terminal acidic residues. This carboxypeptidase was expressed as a recombinant proprotein in the yeast Pichia pastoris. The expressed protein could be activated by treatment with bovine trypsin; degradation of bound pro-region, rather than cleavage of pro-region from mature protein, was the rate-limiting step in activation. Activated HaCA42 carboxypeptidase hydrolysed a synthetic substrate for glutamate carboxypeptidases (FAEE, C-terminal Glu), but did not hydrolyse substrates for carboxypeptidase A or B (FAPP or FAAK, C-terminal Phe or Lys) or methotrexate, cleaved by clan MH glutamate carboxypeptidases. The enzyme was highly specific for C-terminal glutamate in peptide substrates, with slow hydrolysis of C-terminal aspartate also observed. Glutamate carboxypeptidase activity was present in larval gut extract from H. armigera. The HaCA42 protein is the first glutamate-specific metallocarboxypeptidase from clan MC to be identified and characterized. The genome of Drosophila melanogaster contains genes encoding enzymes with similar sequences and predicted specificity, and a cDNA encoding a similar enzyme has been isolated from gut tissue in tsetse fly. We suggest that digestive carboxypeptidases with sequence similarity to the classical mammalian enzymes, but with specificity towards C-terminal glutamate, are widely distributed in insects.

  15. An independent occurrence of the chimeric P450 enzyme CYP337B3 of Helicoverpa armigera confers cypermethrin resistance in Pakistan.

    Science.gov (United States)

    Rasool, Akhtar; Joußen, Nicole; Lorenz, Sybille; Ellinger, Renate; Schneider, Bernd; Khan, Sher Afzal; Ashfaq, Muhammad; Heckel, David G

    2014-10-01

    The increasing resistance level of insect pest species is a major concern to agriculture worldwide. The cotton bollworm, Helicoverpa armigera, is one of the most important pest species due to being highly polyphagous, geographically widespread, and resistant towards many chemical classes of insecticides. We previously described the mechanism of fenvalerate resistance in Australian populations conferred by the chimeric cytochrome P450 monooxygenase CYP337B3, which arose by unequal crossing-over between CYP337B1 and CYP337B2. Here, we show that this mechanism is also present in the cypermethrin-resistant FSD strain from Pakistan. The Pakistani and the Australian CYP337B3 alleles differ by 18 synonymous and three nonsynonymous SNPs and additionally in the length and sequence of the intron. Nevertheless, the activity of both CYP337B3 proteins is comparable. We demonstrate that CYP337B3 is capable of metabolizing cypermethrin (trans- and especially cis-isomers) to the main metabolite 4'-hydroxycypermethrin, which exhibits no intrinsic toxicity towards susceptible larvae. In a bioassay, CYP337B3 confers a 7-fold resistance towards cypermethrin in FSD larvae compared to susceptible larvae from the Australian TWB strain lacking CYP337B3. Linkage analysis shows that presence of CYP337B3 accounts for most of the cypermethrin resistance in the FSD strain; up-regulation of other P450s in FSD plays no detectable role in resistance. The presence or absence of CYP337B3 can be easily detected by a simple PCR screen, providing a powerful tool to rapidly distinguish resistant from susceptible individuals in the field and to determine the geographical distribution of this resistance gene. Our results suggest that CYP337B3 evolved twice independently by unequal crossing-over between CYP337B2 and two different CYP337B1 alleles. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Heterologous expression of Helicoverpa armigera cytochrome P450 CYP6B7 in Pichia pastoris and interactions of CYP6B7 with insecticides.

    Science.gov (United States)

    Zhao, Chunqing; Song, Genmiao; Duan, Hongxia; Tang, Tao; Wang, Chen; Qiu, Lihong

    2017-09-01

    Previous studies indicated that constitutive over-expression of cytochrome P450 CYP6B7 was involved in fenvalerate resistance in Helicoverpa armigera. In this study, the CYP6B7 gene from H. armigera (namely HaCYP6B7), was heterologously expressed in Pichia pastoris GS115. A vector pPICZA-HaCYP6B7 was constructed and transformed into P. pastoris GS115, the transformant of pPICZA-HaCYP6B7-GS115 was then cultured and induced by 1% (v/v) methanol and the heterologous expression of HaCYP6B7 protein in P. pastoris was confirmed by SDS-PAGE and western blot. Microsomes containing the expressed HaCYP6B7 showed activities against model substrate p-nitroanisole and 7-ethoxycoumarin, with p-nitroanisole O-demethylation (PNOD) and 7-ethoxycoumarin O-deethylation (ECOD) activities of 15.66- and 4.75-fold of the control, respectively. Moreover, it showed degradation activities against the insecticides bifenthrin, fenvalerate and chlorpyrifos, with clearance activities of 6.88-, 1.49- and 2.27-fold of the control, respectively. The interactions of HaCYP6B7 with insecticides were further confirmed by molecular docking in silico with binding scores of 5.450, 5.295 and 2.197 between putative HaCYP6B7 protein and bifenthrin, fenvalerate and chlorpyrifos, respectively. The results of present study provided more direct and important evidence on the role of HaCYP6B7 conferring pyrethroid resistance in H. armigera. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  17. Silencing of HaAce1 gene by host-delivered artificial microRNA disrupts growth and development of Helicoverpa armigera.

    Science.gov (United States)

    Saini, Ravi Prakash; Raman, Venkat; Dhandapani, Gurusamy; Malhotra, Era Vaidya; Sreevathsa, Rohini; Kumar, Polumetla Ananda; Sharma, Tilak R; Pattanayak, Debasis

    2018-01-01

    The polyphagous insect-pest, Helicoverpa armigera, is a serious threat to a number of economically important crops. Chemical application and/or cultivation of Bt transgenic crops are the two strategies available now for insect-pest management. However, environmental pollution and long-term sustainability are major concerns against these two options. RNAi is now considered as a promising technology to complement Bt to tackle insect-pests menace. In this study, we report host-delivered silencing of HaAce1 gene, encoding the predominant isoform of H. armigera acetylcholinesterase, by an artificial microRNA, HaAce1-amiR1. Arabidopsis pre-miRNA164b was modified by replacing miR164b/miR164b* sequences with HaAce1-amiR1/HaAce1-amiR1* sequences. The recombinant HaAce1-preamiRNA1 was put under the control of CaMV 35S promoter and NOS terminator of plant binary vector pBI121, and the resultant vector cassette was used for tobacco transformation. Two transgenic tobacco lines expressing HaAce1-amiR1 was used for detached leaf insect feeding bioassays. Larval mortality of 25% and adult deformity of 20% were observed in transgenic treated insect group over that control tobacco treated insect group. The reduction in the steady-state level of HaAce1 mRNA was 70-80% in the defective adults compared to control. Our results demonstrate promise for host-delivered amiRNA-mediated silencing of HaAce1 gene for H. armigera management.

  18. 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

  19. LABORATORY AND FIELD EVALUATION OF ESSENTIAL OILS FROM Cymbopogon nardus AS OVIPOSITION DETERRENT AND OVICIDAL ACTIVITIES AGAINST Helicoverpa armigera Hubner ON CHILI PEPPER

    Directory of Open Access Journals (Sweden)

    Wiwin Setiawati

    2011-04-01

    Full Text Available The fruit borer (Helicoverpa armigera Hubner is one of the key pests of chili pepper in Indonesia. Yield loss due to this insect pest may reach up to 60%. Chemical treatment for con-trolling this insect pest is ineffective and eventually leads to environmental pollution. More environmentally safe insecticides are developed based on natural plant ingredients as their active compound such as essential oils. This study aimed to assess the potential of citronella oil for managing H. armigera on chili pepper. The experiments were conducted at the Indonesian Vegetables Research Institute from April 2009 to March 2010 and in Cirebon, West Java from November 2009 to March 2010. A field experiment was designed in a randomized complete block design with five treatments and replicated five times. Citronella oil was extracted by steam distillation from Cymbo-pogon  nardus. The oil was then chemically characterized by using GC-MS and its efficacy (ovicidal and feeding deterrent against H. armigera was tested both in laboratory and field conditions. The GC-MS result showed that major chemical compounds of the citronella oil used were citronella (35.97%, nerol (17.28%, citronellol (10.03%, geranyle acetate (4.44%, elemol (4.38%, limonene (3.98%, and citronnellyle acetate (3.51%. The laboratory experiment revealed that the highest concentration (4,000 ppm of citronella oil reduced egg laying by 53-66%. Ovicidal activity was concentration dependent, and egg hatchability decreased by 15-95% compared to control. The field experiment showed that treatment of citronella oil at 2.0 mL L-1 significantly reduced fruit damage by H. armigera similar to the plots treated with spinosad at the recommended dose (60 g ai ha-1. Application of citronella oil significantly reduced fruit damage by 72% and increased quality of the chili pepper. Because oviposition and feeding deterrent properties are key factors in controlling the pest, therefore this study revealed that

  20. Over-expression of multiple cytochrome P450 genes in fenvalerate-resistant field strains of Helicoverpa armigera from north of China.

    Science.gov (United States)

    Xu, Li; Li, Dongzhi; Qin, Jianying; Zhao, Weisong; Qiu, Lihong

    2016-09-01

    Pyrethroid resistance was one of the main reasons for control failure of cotton bollworm Helicoverpa armigera (Hübner) in China. The promotion of Bt crops decreased the application of chemical insecticides in controlling H.armigera. However, the cotton bollworm still kept high levels of resistance to fenvalerate. In this study, the resistance levels of 8 field-collected strains of H. armigera from north of China to 4 insecticides, as well as the expression levels of related P450 genes were investigated. The results of bioassay indicated that the resistance levels to fenvalerate in the field strains varied from 5.4- to 114.7-fold, while the resistance levels to lambda-cyhalothrin, phoxim and methomyl were low, which were ranged from 1.5- to 5.2-, 0.2- to 1.6-, and 2.9- to 8.3- fold, respectively, compared to a susceptible strain. Synergistic experiment showed that PBO was the most effective synergist in increasing the sensitivity of H. armigera to fenvalerate, suggesting that P450 enzymes were involved in the pyrethroid resistance in the field strains. The results of quantitative RT-PCR indicated that eight P450 genes (CYP332A1, CYP4L11, CYP4L5, CYP4M6, CYP4M7, CYP6B7, CYP9A12, CYP9A14) were all significantly overexpressed in Hejian1 and Xiajin1 strains of H. armigera collected in 2013, and CYP4L5 was significantly overexpressed in all the 6 field strains collected in 2014. CYP332A1, CYP6B7 and CYP9A12 had very high overexpression levels in all the field strains, indicating their important roles in fenvalerate resistance. The results suggested that multiple P450 genes were involved in the high-level fenvalerate-resistance in different field strains of H. armigera collected from north of China. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. 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.

  2. 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.

  3. Effectiveness of two insect growth regulators against Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) and their impact on population densities of arthropod predators in cotton in Pakistan.

    Science.gov (United States)

    Gogi, Muhammad D; Sarfraz, Rana M; Dosdall, Lloyd M; Arif, Muhammad J; Keddie, Andrew B; Ashfaq, Muhammad

    2006-10-01

    Field efficacies of two insect growth regulators (IGRs) at two recommended application rates, buprofezin at 370 and 555 g AI ha(-1) and lufenuron at 37 and 49 g AI ha(-1), were determined against the sweet potato whitefly, Bemisia tabaci (Gennadius), and the cotton bollworm, Helicoverpa armigera (Hübner), in experimental plots of cotton at the Directorate of Cotton Research, Faisalabad, Pakistan. Adverse effects of the IGRs on populations of associated arthropod predators, namely geocorids, chrysopids, coccinellids, formicids and arachnids, were also assessed. Both IGRs significantly reduced populations of B. tabaci at each application rate 24, 48 and 72 h after treatment, and higher doses were more effective than lower doses. Buprofezin was not effective against H. armigera at any tested dose for any time of treatment in any spray. Lufenuron applied at 37 and 49 g AI ha(-1) effectively suppressed H. armigera populations, resulting in significant reductions in crop damage. At lower doses, both IGRs appeared safe to predator populations, which did not differ significantly in IGR-treated versus untreated control plots. Population densities of formicids and coccinellids were significantly lower at high concentrations of both IGRs in treatment plots, possibly as a result of reduced prey availability. The potential role of buprofezin and lufenuron for control of B. tabaci and H. armigera in a spray programme and the likelihood of direct toxic effects of IGRs on predatory fauna of cotton are discussed.

  4. Expression of a Chimeric Gene Encoding Insecticidal Crystal Protein Cry1Aabc of Bacillus thuringiensis in Chickpea (Cicer arietinum L.) Confers Resistance to Gram Pod Borer (Helicoverpa armigera Hubner.).

    Science.gov (United States)

    Das, Alok; Datta, Subhojit; Thakur, Shallu; Shukla, Alok; Ansari, Jamal; Sujayanand, G K; Chaturvedi, Sushil K; Kumar, P A; Singh, N P

    2017-01-01

    Domain swapping and generation of chimeric insecticidal crystal protein is an emerging area of insect pest management. The lepidopteran insect pest, gram pod borer ( Helicoverpa armigera H.) wreaks havoc to chickpea crop affecting production. Lepidopteran insects were reported to be controlled by Bt ( cryI ) genes. We designed a plant codon optimized chimeric Bt gene ( cry1Aabc ) using three domains from three different cry1A genes (domains I, II, and III from cry1Aa , cry1Ab , and cry1Ac , respectively) and expressed it under the control of a constitutive promoter in chickpea ( cv . DCP92-3) to assess its effect on gram pod borer. A total of six transgenic chickpea shoots were established by grafting into mature fertile plants. The in vitro regenerated (organogenetic) shoots were selected based on antibiotic kanamycin monosulfate (100 mg/L) with transformation efficiency of 0.076%. Three transgenic events were extensively studied based on gene expression pattern and insect mortality across generations. Protein expression in pod walls, immature seeds and leaves (pre- and post-flowering) were estimated and expression in pre-flowering stage was found higher than that of post-flowering. Analysis for the stable integration, expression and insect mortality (detached leaf and whole plant bioassay) led to identification of efficacious transgenic chickpea lines. The chimeric cry1Aabc expressed in chickpea is effective against gram pod borer and generated events can be utilized in transgenic breeding program.

  5. Expression of a Chimeric Gene Encoding Insecticidal Crystal Protein Cry1Aabc of Bacillus thuringiensis in Chickpea (Cicer arietinum L. Confers Resistance to Gram Pod Borer (Helicoverpa armigera Hubner.

    Directory of Open Access Journals (Sweden)

    Alok Das

    2017-08-01

    Full Text Available Domain swapping and generation of chimeric insecticidal crystal protein is an emerging area of insect pest management. The lepidopteran insect pest, gram pod borer (Helicoverpa armigera H. wreaks havoc to chickpea crop affecting production. Lepidopteran insects were reported to be controlled by Bt (cryI genes. We designed a plant codon optimized chimeric Bt gene (cry1Aabc using three domains from three different cry1A genes (domains I, II, and III from cry1Aa, cry1Ab, and cry1Ac, respectively and expressed it under the control of a constitutive promoter in chickpea (cv. DCP92-3 to assess its effect on gram pod borer. A total of six transgenic chickpea shoots were established by grafting into mature fertile plants. The in vitro regenerated (organogenetic shoots were selected based on antibiotic kanamycin monosulfate (100 mg/L with transformation efficiency of 0.076%. Three transgenic events were extensively studied based on gene expression pattern and insect mortality across generations. Protein expression in pod walls, immature seeds and leaves (pre- and post-flowering were estimated and expression in pre-flowering stage was found higher than that of post-flowering. Analysis for the stable integration, expression and insect mortality (detached leaf and whole plant bioassay led to identification of efficacious transgenic chickpea lines. The chimeric cry1Aabc expressed in chickpea is effective against gram pod borer and generated events can be utilized in transgenic breeding program.

  6. Análise da variabilidade genética de populações de Helicoverpa armigera (Lepidoptera: Noctuidae) ocorrendo em culturas de algodão e tomate - doi: 10.5102/ucs.v8i1.1056

    OpenAIRE

    Queiroz, Paulo Roberto; Lima, Luzia Helena Corrêa

    2010-01-01

    Helicoverpa armigera é uma das principais pragas polífagas de distribuição mundial das culturas de interesse econômico. A identificação dessa espécie por meio molecular auxilia no estabelecimento do perfil genético, na caracterização e no monitoramento das populações desse inseto da ordem Lepidoptera. O objetivo desse trabalho foi estabelecer uma metodologia de extração de DNA para H. armigera, determinar perfis eletroforéticos e analisar a variabilidade genética entre as populações desse ins...

  7. Análise da variabilidade genética de populações de Helicoverpa armigera (Lepidoptera: Noctuidae ocorrendo em culturas de algodão e tomate - doi: 10.5102/ucs.v8i1.1056

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Queiroz

    2010-10-01

    Full Text Available Helicoverpa armigera é uma das principais pragas polífagas de distribuição mundial das culturas de interesse econômico. A identificação dessa espécie por meio molecular auxilia no estabelecimento do perfil genético, na caracterização e no monitoramento das populações desse inseto da ordem Lepidoptera. O objetivo desse trabalho foi estabelecer uma metodologia de extração de DNA para H. armigera, determinar perfis eletroforéticos e analisar a variabilidade genética entre as populações desse inseto-praga. Os cinco iniciadores de RAPD produziram fragmentos de DNA que revelaram uma similaridade genética inferior a 80% entre as dez populações no dendrograma que foi gerado. Os resultados obtidos com as análises de variância molecular (AMOVA revelaram que a elevada fonte de variação genética foi o resultado da variabilidade dentro de cada população. As causas que levaram a essa elevada variabilidade precisam ser mais bem estudadas nos países onde a praga ocorre.

  8. Microbial agents against Helicoverpa armigera: Where are we and ...

    African Journals Online (AJOL)

    SAM

    2014-04-30

    Apr 30, 2014 ... feed and fibre around the world. Different approaches namely: .... biocontrol agent from the fungus Trichoderma harzianum was also evaluated .... the antibiotic biosynthetic gene transfer (Baltz, 2005). Overall 23,000 bioactive ...

  9. Modeling biological disturbances in LANDIS: a module description and demonstration using spruce budworm

    Science.gov (United States)

    Brian R. Sturtevant; Eric J. Gustafson; Wei Li; Hong S. He

    2004-01-01

    Insects and diseases are common disturbance agents in forested ecosystems. Severe outbreaks can cause significant changes in tree species composition, age structure, and fuel conditions over broad areas. To investigate the role of biological disturbances in shaping forest landscapes over time, we constructed a new "biological disturbance agent" (BDA) module...

  10. Douglas-fir nutrients and terpenes as potential factors influencing western spruce budworm defoliation

    Science.gov (United States)

    Karen M. Clancy

    1991-01-01

    Variation in levels of herbivory within and among plants can be attributed to many mechanisms, such as differences in a) host nutritional quality, b) suitability of the physical environment, and c) abundance of competitor consumers or natural enemies (Mattson et al. 1982, Denno and McClure 1983, Mattson and Scriber 1987, Clancy et al. 1988a, 1988b, Mattson et al. 1988...

  11. Characterization of EST-based SSR loci in the spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae)

    Science.gov (United States)

    B.M.T. Brunet; D. Doucet; B.R. Sturtevant; F.A.H. Sperling

    2013-01-01

    After identifying 114 microsatellite loci from Choristoneura fumiferana expressed sequence tags, 87 loci were assayed in a panel of 11 wild-caught individuals, giving 29 polymorphic loci. Further analysis of 20 of these loci on 31 individuals collected from a single population in northern Minnesota identified 14 in Hardy-Weinberg equilibrium.

  12. Representation of pheromones, interspecific signals, and plant odors in higher olfactory centers; mapping physiologically identified antennal-lobe projection neurons in the male heliothine moth

    Directory of Open Access Journals (Sweden)

    Xin-Cheng eZhao

    2014-10-01

    Full Text Available In the primary olfactory centre of the moth brain, for example, a few enlarged glomeruli situated dorsally, at the entrance of the antennal nerve, are devoted to information about female-produced substances whereas a set of more numerous ordinary glomeruli receives input about general odorants. Heliothine moths are particularly suitable for studying central chemosensory mechanisms not only because of their anatomically separated systems for plant odours and pheromones but also due to their use of female-produced substances in communication across the species. Thus, the male-specific system of heliothine moths includes two sub arrangements, one ensuring attraction and mating behavior by carrying information about pheromones released by conspecifics, and the other reproductive isolation via signal information emitted from heterospecifics. Based on previous tracing experiments, a general chemotopic organization of the male-specific glomeruli has been demonstrated in a number of heliothine species. As compared to the well explored organization of the moth antennal lobe, demonstrating a non-overlapping representation of the biologically relevant stimuli, less is known about the neural arrangement residing at the following synaptic level, i.e. the mushroom body calyces and the lateral horn. In the study presented here, we have labelled physiologically characterized antennal-lobe projection neurons in males of the two heliothine species, Heliothis virescens and Helicoverpa assulta, for the purpose of mapping their target regions in the protocerebrum. In order to compare the representation of plant odours, pheromones, and interspecific signals in the higher brain regions of each species, we have created standard brain atlases and registered three-dimensional models of distinct uniglomerular projection neuron types into the relevant atlas.

  13. Impacts on transfer of the sperm of helicoverpa Armigera by irradiation (L. noctuidae)

    International Nuclear Information System (INIS)

    Liu Xiaohui; Li Yongjun; Wang Huasong; Song Jiaxiang

    2001-01-01

    Gamma irradiation did not influence the quantity of the eupyrene sperm bundles in duplex and that of the eupyrene sperm in spermatophore, but affected the maturing of eupyrene sperm bundles. When males were given sterilizing dose of 400 Gy, the quantity and the activity of the eupyrene sperm in the spermatheca were reduced significantly (P < 0.05)

  14. 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%.

  15. Screening of tomato genotypes for resistance to tomato fruit borer (helicoverpa armiger hubner) in Pakistan

    International Nuclear Information System (INIS)

    Sajjad, M.; Ashfaq, M.; Suhail, A.

    2011-01-01

    Tomato genotypes viz., Roma Local, Rio Grande, Tanja, Chico III, Long Tipped, Red-Top, FS-8001, FS-8002, Tropic, Pakit, Peelo, NARC-1, Roma VFN, Pant Bahr, Ebein, Nova Mech, Rockingham, Nagina, Shalkot-96, Pomodoro, Manik, Gressilesse, Nadir, Early Mech, Tommy, Pusha Rubi, Tropic boy, Big Long, Sahil, Sun 6002, Money-Maker and Royesta were evaluated to screen out the suitable resistant/susceptible genotypes against the fruit borer in Pakistan. The results imparted that the percentage of fruit infestation and larval population per plant on tested genotypes of tomato varied significantly. Roma VF, NARC-1 and FS-8002 were categorized as susceptible genotypes with fruit infestation (37.69%, 37.08% and 36.41%, respectively) and larval population per plant (1.02%, 1.02% and 0.84 %, respectively). Whereas, the genotypes Sahil, Pakit and Nova Mecb had fruit infestation (12.30%, 13.14% and 13.96%, respectively) and larval population per plant (0.42%, 0.42% and 0.43%, respectively) and declared as resistant genotypes to tomato fruit borer. Lower values of host plant susceptibility indices (HPSI) were recorded on resistant genotypes. Sahil, Pakit and Nova Mecb could be used as a source of resistance for developing tomato genotypes resistant to tomato fruit borer. (author)

  16. Sterilization of Helicoverpa armigera (hubner) moth (lepidoptera; Noctudae) by using Gamma rays radiation

    International Nuclear Information System (INIS)

    Subiyakto; Wari D Astati; Sunarto Dwi A

    1998-01-01

    This experiment was conducted at the Radiation Facility, National Atomic Energy, Jakarta and Entomology Laboratory of the Research Institute for Tobacco and Crops Malang in 1991. Sterilization of moth by radiating insect on pupae stage. The dosage were 0 (unradiated), 1,3,5,7,9,11,13,and 15 krad. The treatments were arranged in complete randomized design with three replications. Each treatments were made variation of copulation (1) two females radiated with a make unradiated (2) two females unradiated with a male radiated, and (3) two females radiated with a male radiated. The results showed that sub sterile dosage (LD 50 ) for male was 0.94 krad and 7.02 krad for female. The sterile dosage (LD 95 ) for male was 10.85 krad and 14.35 krad for female. Research of the competition for copulation between the male radiated and unradiated is needed. (author)

  17. Keanekaragaman spesies parasitoid telur Helicoverpa armigera (Hübner pada sistem tanam monokultur dan polikultur kapas

    Directory of Open Access Journals (Sweden)

    nurindah nurindah

    2017-02-01

    Full Text Available Polyculture system is one of techniques in pest management. In Indonesia, cotton is always intercropped with second food crops such as maize, soybean, mungbean or peanut. This research was aimed to evaluate the effect of culture system, i.e. cotton monoculture vs. cotton intercropped with soybean on the increase of species diversity of H. armigera egg parasitoids and the parasitoid contribution to mortality of H. armigera. The research was arranged in a split plot design with two main factors: three cotton varieties with three levels of trichome density (Tamcot SP 37, Kanesia 8 and LRA 5166 and the subplots were two cultivation systems (cotton monoculture and polyculture, with three replicates. Observations were made by collecting H. armigera eggs on population of first generation (45 days after planting and second generation (75 DAP. The results showed that on cotton polyculture the egg parasitoid complex which consisted of Trichogramma spp. and Trichogrammatoidea spp. was higher than that in cotton monoculture and so was the egg parasitism level. The increase of egg parasitism was 24% in the first generation and 15% in the second generation. Parasitoid species found belonged to the genera Trichogramma and Trichogrammatoidea. In the parasitoid complex, Trichogrammatoidea armigera was dominant on the first generation and Trichogramma chilotraeae on the second. The domination succession could be as a result of the higher host-searching capacity of T. chilotraeae than that of T. armigera.

  18. Performance of the Forest Vegetation Simulator in managed white spruce plantations influenced by eastern spruce budworm in northern Minnesota

    Science.gov (United States)

    Matthew B. Russell; Anthony W. D' Amato; Michael A. Albers; Christopher W. Woodall; Klaus J. Puettmann; Michael R. Saunders; Curtis L. VanderSchaaf

    2015-01-01

    Silvicultural strategies such as thinning may minimize productivity losses from a variety of forest disturbances, including forest insects. This study analyzed the 10-year postthinning response of stands and individual trees in thinned white spruce (Picea glauca [Moench] Voss) plantations in northern Minnesota, USA, with light to moderate defoliation...

  19. CRISPR/Cas9 mediated high efficiency knockout of the eye color gene vermillion in Helicoverpa zea (Boddie)

    Science.gov (United States)

    Among various genome editing tools available for functional genomic studies, reagents based on clustered regularly interspersed palindromic repeats (CRISPR) have gained popularity due to ease and versatility. CRISPR reagents consists of ribonucleoprotein (RNP) complexes formed by combining guide RNA...

  20. Aromatic/heterocyclic amino acids and the simulated sunlight-ultraviolet inactivation of the Heliothis/Helicoverpa baculovirus

    International Nuclear Information System (INIS)

    Ignoffo, C.M.; Garcia, C.

    1995-01-01

    Tryptophan, of five aromatic/heterocyclic amino acids (tyrosine, phenylalanine, proline, histidine) provided significant protection of the Heliothis baculovirus (HzSNPV) from inactivation by simulated ultraviolet (SUV). Fifty percent of SUV protection of HzSNPV with tryptophan or tyrosine was obtained at 0.03 mg/ml and 0.5 mg/ml, respectively. Rates as high as 100.0 mg/ml of phenylalanine, histidine, or proline provided <50% protection. The extent of tryptophan protection was correlated with its absorption in the sunlight UV-B spectra. 16 refs., 2 tabs

  1. 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

  2. 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)

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

    2014-01-01

    Insect outbreaks are often assumed to increase the severity or probability of fire occurrence through increased fuel availability, while fires may in turn alter susceptibility of forests to subsequent insect outbreaks through changes in the spatial distribution of suitable host trees. However, little is actually known about the potential synergisms between these...

  3. 77 FR 2539 - Pesticide Experimental Use Permit; Receipt of Application; Comment Request

    Science.gov (United States)

    2012-01-18

    ...), tobacco budworm (Heliothis virescens), pink bollworm (Pectinophora gossypiella), fall armyworm (Spodoptera frugiperda), and beet armyworm (Spodoptera exigua). A copy of the application and any information submitted...

  4. Structure and transcription of the Helicoverpa armigera densovirus (HaDV2) genome and its expression strategy in LD652 cells.

    Science.gov (United States)

    Xu, Pengjun; Graham, Robert I; Wilson, Kenneth; Wu, Kongming

    2017-02-07

    Densoviruses (DVs) are highly pathogenic to their hosts. However, we previously reported a mutualistic DV (HaDV2). Very little was known about the characteristics of this virus, so herein we undertook a series of experiments to explore the molecular biology of HaDV2 further. Phylogenetic analysis showed that HaDV2 was similar to members of the genus Iteradensovirus. However, compared to current members of the genus Iteradensovirus, the sequence identity of HaDV2 is less than 44% at the nucleotide-level, and lower than 36, 28 and 19% at the amino-acid-level of VP, NS1 and NS2 proteins, respectively. Moreover, NS1 and NS2 proteins from HaDV2 were smaller than those from other iteradensoviruses due to their shorter N-terminal sequences. Two transcripts of about 2.2 kb coding for the NS proteins and the VP proteins were identified by Northern Blot and RACE analysis. Using specific anti-NS1 and anti-NS2 antibodies, Western Blot analysis revealed a 78 kDa and a 48 kDa protein, respectively. Finally, the localization of both NS1 and NS2 proteins within the cell nucleus was determined by using Green Fluorescent Protein (GFP) labelling. The genome organization, terminal hairpin structure, transcription and expression strategies as well as the mutualistic relationship with its host, suggested that HaDV2 was a novel member of the genus Iteradensovirus within the subfamily Densovirinae.

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

    OpenAIRE

    Baozhu Guo; Ana Butrón; Brian T. Scully

    2010-01-01

    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, mays...

  6. Expression of a maize Myb transcription factor driven by a putative silk-specific promoter significantly enhances resistance to Helicoverpa zea in transgenic maize.

    Science.gov (United States)

    Johnson, Eric T; Berhow, Mark A; Dowd, Patrick F

    2007-04-18

    Hi II maize (Zea mays) plants were engineered to express maize p1 cDNA, a Myb transcription factor, controlled by a putative silk specific promoter, for secondary metabolite production and corn earworm resistance. Transgene expression did not enhance silk color, but about half of the transformed plant silks displayed browning when cut, which indicated the presence of p1-produced secondary metabolites. Levels of maysin, a secondary metabolite with insect toxicity, were highest in newly emerged browning silks. The insect resistance of transgenic silks was also highest at emergence, regardless of maysin levels, which suggests that other unidentified p1-induced molecules likely contributed to larval mortality. Mean survivor weights of corn earworm larvae fed mature browning transgenic silks were significantly lower than weights of those fed mature nonbrowning transgenic silks. Some transgenic pericarps browned with drying and contained similar molecules found in pericarps expressing a dominant p1 allele, suggesting that the promoter may not be silk-specific.

  7. 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

  8. 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

  9. Phylogenetic and functional characterization of ten P450 genes from the CYP6AE subfamily of Helicoverpa armigera involved in xenobiotic metabolism

    DEFF Research Database (Denmark)

    Shi, Yu; Wang, Huidong; Liu, Zhi

    2018-01-01

    450s in this subfamily can metabolise imidacloprid, but with lower efficiency than Bemisia tabaci CYP6CM1vQ. CYP6AE20 had virtually no metabolic competence to these four compounds but could metabolise several model fluorogenic substrates. These results showed the broad substrate spectrum of H...

  10. How does synchrony with host plant affect the performance of an outbreaking insect defoliator?

    Science.gov (United States)

    Fuentealba, Alvaro; Pureswaran, Deepa; Bauce, Éric; Despland, Emma

    2017-08-01

    Phenological mismatch has been proposed as a key mechanism by which climate change can increase the severity of insect outbreaks. Spruce budworm (Choristoneura fumiferana) is a serious defoliator of North American conifers that feeds on buds in the early spring. Black spruce (Picea mariana) has traditionally been considered a poor-quality host plant since its buds open later than those of the preferred host, balsam fir (Abies balsamea). We hypothesize that advancing black spruce budbreak phenology under a warmer climate would improve its phenological synchrony with budworm and hence increase both its suitability as a host plant and resulting defoliation damage. We evaluated the relationship between tree phenology and both budworm performance and tree defoliation by placing seven cohorts of budworm larvae on black spruce and balsam fir branches at different lags with tree budburst. Our results show that on both host plants, spruce budworm survival and pupal mass decrease sharply when budbreak occurs prior to larval emergence. By contrast, emergence before budbreak decreases survival, but does not negatively impact growth or reproductive output. We also document phytochemical changes that occur as needles mature and define a window of opportunity for the budworm. Finally, larvae that emerged in synchrony with budbreak had the greatest defoliating effect on black spruce. Our results suggest that in the event of advanced black spruce phenology due to climate warming, this host species will support better budworm survival and suffer increased defoliation.

  11. Variation in phenology and monoterpene patterns of defoliated and nondefoliated Douglas-fir (Pseudotsuga menziesii var. glauca).

    Science.gov (United States)

    Rose-Marie Muzika; Judith Engle; Catherine Parks; Boyd. Wickman

    1993-01-01

    Foliage was collected from paired Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) trees characterized as either "resistant" or "susceptible" western spruce budworm (Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae) attack. Resistant trees produced more...

  12. Low volume undiluted Btk application against heavy gypsy moth population densities in southern Corsica

    Science.gov (United States)

    Robert A. Fusco; Jean-Claude Martin

    2003-01-01

    Low volume undiluted applications of Bacillus thuringiensis are common and efficacious against coniferous forest pests such as pine processionary moth and spruce budworm, but have not been common practice against deciduous forest pests due to coverage issues.

  13. An RNAi construct of the P450 gene CYP82D109 leads to increased resistance to Fusarium oxysporum f. sp. vasinfectum (Fov11) and increased feeding by Helicoverpa Zea larvae

    Science.gov (United States)

    The P450 CYP82D109 gene codes for an early step enzyme in the gossypol pathway in Gossypium. The terminal leaves of RNAi plants had a 90% reduction in hemigossypolone and heliocides levels, and a 70% reduction in gossypol levels compared to wild-type (WT) plants. Previous studies comparing glanded...

  14. Engineered chloroplast dsRNA silences cytochrome p450 monooxygenase, V-ATPase and chitin synthase genes in the insect gut and disrupts Helicoverpa zea larval development and pupation.

    Science.gov (United States)

    Jin, Shuangxia; Singh, Nameirakpam D; Li, Lebin; Zhang, Xianlong; Daniell, Henry

    2015-04-01

    In the past two decades, chloroplast genetic engineering has been advanced to achieve high-level protein accumulation but not for down-regulation of targeted genes. Therefore, in this report, lepidopteran chitin synthase (Chi), cytochrome P450 monooxygenase (P450) and V-ATPase dsRNAs were expressed via the chloroplast genome to study RNA interference (RNAi) of target genes in intended hosts. PCR and Southern blot analysis confirmed homoplasmy and site-specific integration of transgene cassettes into the chloroplast genomes. Northern blots and real-time qRT-PCR confirmed abundant processed and unprocessed dsRNA transcripts (up to 3.45 million copies of P450 dsRNAs/μg total RNA); the abundance of cleaved dsRNA was greater than the endogenous psbA transcript. Feeding of leaves expressing P450, Chi and V-ATPase dsRNA decreased transcription of the targeted gene to almost undetectable levels in the insect midgut, likely after further processing of dsRNA in their gut. Consequently, the net weight of larvae, growth and pupation rates were significantly reduced by chloroplast-derived dsRNAs. Taken together, successful expression of dsRNAs via the chloroplast genome for the first time opens the door to study RNA interference/processing within plastids. Most importantly, dsRNA expressed in chloroplasts can be utilized for gene inactivation to confer desired agronomic traits or for various biomedical applications, including down-regulation of dysfunctional genes in cancer or autoimmune disorders, after oral delivery of dsRNA bioencapsulated within plant cells. © 2015 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  15. The influence of the temperature at the intensity of the spread of the cotton bollworm (heliothis obsoleta fabr. = helicoverpa armigera hb.) as a pest of the peppers in the Strumica region

    OpenAIRE

    Spasov, Dusan; Spasova, Dragica; Ilievski, Mite; Atanasova, Biljana

    2015-01-01

    H. armigera is typical polyphagous insect which attacks: tomatoes, peppers, tobacco, maize, cotton, garlic, onions, cabbage, soy, beans and many other leguminous and pumpkin crops and various weed plants. The damages from the cotton bollworm have economic importance, especially when the species is in progradation. It is widespread all over the world, especially in warmer climates. The increase in the population of this cotton bollworm is associated with global warming.

  16. 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...

  17. Characterisation of Bacillus thuringiensis kurstaki strains by toxicity ...

    African Journals Online (AJOL)

    , dipel, HD73, HD1dipel) were characterized by investigating their total plasmid profiling; cryIA genes profiling and toxicity towards local isolates of agricultural insects Helicoverpa armigera and Spodoptera litura. Result showed that LC50 for S.

  18. Transgenic Bacillus thuringiensis (Bt) chickpea: India's most wanted ...

    African Journals Online (AJOL)

    Sumita

    2013-09-25

    Sep 25, 2013 ... most wanted genetically modified (GM) pulse crop. Sumita Acharjee and Bidyut ... (predominantly, Helicoverpa armigera) and diseases, lack of supply of quality seeds, ... emerging from winter diapause. The trap crops are.

  19. Using dendrochronology to measure radial growth of defoliated trees

    Science.gov (United States)

    Thomas W. Swetnam; Marna Ares Thompson; Elaine Kennedy. Sutherland

    1985-01-01

    Budworms (Choristoneura spp.) have repeatedly defoliated millions of hectares of conifers throughout North America. The seriousness of the problem is underscored by research findings in eastern Canada and the northern U.S. Rocky Mountains that the extent, severity, and frequency of bud worm outbreaks have increased in the 20th century, primarily as a result of human-...

  20. 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...

  1. Dispersal of forest insects

    Science.gov (United States)

    Mcmanus, M. L.

    1979-01-01

    Dispersal flights of selected species of forest insects which are associated with periodic outbreaks of pests that occur over large contiguous forested areas are discussed. Gypsy moths, spruce budworms, and forest tent caterpillars were studied for their massive migrations in forested areas. Results indicate that large dispersals into forested areas are due to the females, except in the case of the gypsy moth.

  2. Effects of 1,1-Dimethylpiperidinium Chloride on the Pests and Allelochemicals of Cotton and Pecan.

    Science.gov (United States)

    P. A. Hedin; J. N. Jenkins; J. C. McCarty; J. E. Mulrooney; W. L. Parrott; A. Borazjani; C. H. Graves; T. H. Filer

    1984-01-01

    The growth regulator, PIX (mepiquat chloride - 1,1-dimethyl-piperdinium chloride), when applied to cotton (Gossypium hirsutum L.) and pecan (Carya illinoensis Koch), caused internode shortening. PIX did not elicit an increase in resistance in cotton to the tobacco budworm (Heliothis virescens (Fab.)], or in pecan...

  3. Losing Chlordimeform Use in Cotton Production. Its Effects on the Economy and Pest Resistance. Agricultural Economic Report Number 587.

    Science.gov (United States)

    Osteen, Craig; Suguiyama, Luis

    This report examines the economic implications of losing chlordimeform use on cotton and considers chlordimeform's role in managing the resistance of bollworms and tobacco budworms to synthetic pyrethroids. It estimates changes in prices, production, acreage, consumer expenditures, aggregate producer returns, regional crop effects, and returns to…

  4. Multi-sensor data fusion for estimating forest species composition and abundance in northern Minnesota

    Science.gov (United States)

    Peter P. Wolter; Phillip A. Townsend

    2011-01-01

    The magnitude, duration, and frequency of forest disturbance caused by the spruce budworm and forest tent caterpillar in northern Minnesota and neighboring Ontario, Canada have increased over the last century due to a shift in forest species composition linked to historical fire suppression, forest management, and pesticide application that has fostered increased...

  5. Survival and development of Heliothis virescens (Lepidoptera: Noctuidae) larvae on isogenic tobacco lines with different levels of alkaloids.

    Science.gov (United States)

    Jackson, D Michael; Johnson, A W; Stephenson, M G

    2002-12-01

    Levels of pyridine alkaloids were measured in 18 tobacco, Nicotiana tabacum L., entries from three parental isolines ('NC 95', 'SC 58', and 'Coker 139'), grown at Tifton, GA, Florence, SC, and Oxford, NC, in 1991. Levels of alkaloids in bud leaves (first fully unfolded leaf below the apical leaf bud) were negatively correlated to natural infestation ratings of tobacco budworm larvae, Heliothis virescens (F.), 7 wk after transplanting. For artificially infested bud leaves at Oxford, there was a significant negative correlation between levels of total alkaloids and larval weights after 1 wk of feeding. In 1992, four entries from the 'NC 95' isoline were grown at Oxford, and samples for alkaloid analyses were taken every 2 wk at several leaf positions on each plant. During weeks 4, 8, 12, and 16, second instar tobacco budworms were caged on individual, intact leaves inside perforated plastic bags in the field. The survival and development of tobacco budworm larvae after 1 wk were negatively correlated with levels of alkaloids at the various leaf positions. Larvae survived better and grew faster on the bud leaves of each entry where alkaloid levels were lower than they did on leaves further down the stalk where alkaloid levels were higher. More larvae survived on the lower leaves of the low alkaloid lines than on the lower leaves of the high alkaloid lines. Even moderate increases in pyridine alkaloids had negative effects on tobacco budworm survival and development. Nicotine constituted >97% of the pyridine alkaloids in the 'NC95' isoline each year.

  6. Estimation of forest structural parameters using 5 and 10 meter SPOT-5 satellite data

    Science.gov (United States)

    Peter T. Wolter; Phillip A. Townsend; Brian R. Sturtevant

    2009-01-01

    Large areas of forest in the US and Canada are affected by insects and disease each year. Over the past century, outbreaks of the Eastern spruce budworm have become more frequent and severe. The notion of designing a more pest resistant landscape through prescriptive management practices hinges on our ability to effectively model forest?insect dynamics at regional...

  7. Bryoid layer response to soil disturbance by fuel reduction treatments in a dry conifer forest

    Science.gov (United States)

    Amanda Hardman; Bruce McCune

    2010-01-01

    We investigated the response of the bryoid layer, bryophyte and lichen communities on the soil surface three years after fuel reduction treatment (logging and burning) in the central Blue Mountains of eastern Oregon. Both treatment and control areas had been decimated by spruce budworm and drought before the fuel reduction treatments. Treatments reduced overstory and...

  8. Wisconsin's forest resources in 2004

    Science.gov (United States)

    Charles H. Perry

    2006-01-01

    Results of the 2000-2004 annual inventory of Wisconsin show about 16.0 million acres of forest land, more than 22.1 billion cubic feet of live volume on forest land, and nearly 593 million dry tons of all live aboveground tree biomass on timberland. Populations of jack pine budworm are increasing, and it remains a significant pest in Wisconsin forests. A complete...

  9. Results of forest insect and disease surveys in the central region of Ontario, 1994. Information report No. O-X-448. Annual publication

    Energy Technology Data Exchange (ETDEWEB)

    Evans, H.J.

    1995-12-31

    Report summarizing forest damage by insects, diseases and abiotic conditions in the Central Region of Ontario. Textual descriptions of pests are accompanied by maps and statistical tables. Pest conditions covered include pine false webworm, budworms, shoot borers, leafcutters, armillaria root rot and other diseases and insects. Abiotic damage reported on covers forest decline, frost injury, salt and wind damage, and winter drying. Forest health reports and special surveys are also described.

  10. genome-wide association and metabolic pathway analysis of corn earworm resistance in maize

    Science.gov (United States)

    Marilyn L. Warburton; Erika D. Womack; Juliet D. Tang; Adam Thrash; J. Spencer Smith; Wenwei Xu; Seth C. Murray; W. Paul Williams

    2018-01-01

    Maize (Zea mays mays L.) is a staple crop of economic, industrial, and food security importance. Damage to the growing ears by corn earworm [Helicoverpa zea (Boddie)] is a major economic burden and increases secondary fungal infections and mycotoxin levels. To identify biochemical pathways associated with native resistance mechanisms, a genome-wide...

  11. Impact of transgenic sweet corn silks to two noctuid pests

    Science.gov (United States)

    Eight Bacillus thuringiensis (Bt) transgenic sweet corn hybrids were evaluated (with two controls) for their efficacy against two ear-feeding insects; the corn earworm [Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae)], and the fall armyworm (Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuid...

  12. African Journal of Biotechnology - Vol 11, No 30 (2012)

    African Journals Online (AJOL)

    Propagation physiology of Juniperus phoenicea L. from Jordan using seeds and in vitro culture techniques: Baseline information for a conservation perspective ... Morphological and chemical characteristics of tomato foliage as mechanisms of resistance to Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larvae ...

  13. DNA synthesis in the imaginal wing discs of the American bollworm ...

    Indian Academy of Sciences (India)

    Unknown

    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.

  14. Re-evaluation of the PBAN receptor molecule: characterization of PBANR variants expressed in the pheromone glands of moths

    Science.gov (United States)

    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...

  15. Effects of temperature and nonionizing ultraviolet radiation treatments of eggs of five host insects on production of Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) for biological control applications.

    Science.gov (United States)

    Trichogramma are used worldwide as biological control against insect pests, attacking eggs of over 200 species. Eggs of Spodoptera litura, Corcyra cephalonica, Plutella xylostella and Helicoverpa armigera were tested to consider the effect of temperature and radiation on parasitization, emergence of...

  16. Journal of Applied Sciences and Environmental Management - Vol ...

    African Journals Online (AJOL)

    Antifeedant and Toxic Effect of Crude Extract from Flourensia oolepis and their Impact on Nutritional Parameters of Helicoverpa gelotopoeon · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. C Seminara, L Bollati, S Avalos, G Diaz Napal, SM Palacios, MT Defagó ...

  17. Effect of eastern gamagrass on fall armyworm and corn earworm development

    Science.gov (United States)

    The fall armyworm, Spodoptera frugiperda (J.E. Smith) and the corn earworm, Helicoverpa zea (Boddie) are two important corn pests in the southern U.S. states. Effect of the leaves from the corn relative, the Eastern gamagrass (Tripsacum dactyloides L.) on fall armyworm and corn earworm development ...

  18. Efficacy of silk channel injections with insecticides for management of Lepidopteran pests of sweet corn

    Science.gov (United States)

    The primary Lepidopteran pests of sweet corn in Georgia are the corn earworm, Helicoverpa zea (Boddie), and the fall armyworm, Spodoptera frugiperda (J.E. Smith). Control of these pests typically requires multiple insecticide applications from first silking until harvest, with commercial growers fre...

  19. 2528-IJBCS-Article-Cocou A Djihinto

    African Journals Online (AJOL)

    hp

    (endosulfan 700 g/ha) pour le contrôle des populations de Aphis gossypii, Pectinophora gossypiella et .... chaque ligne mesure 20 mètres de longeur. .... performance de Fanga 500 EC en milieu réel ..... fenêtre et gestion de Helicoverpa.

  20. Supplemental diets containing yeast, sucrose, and soy powder enhance the survivorship, growth, and development of prey-limited cursorial spiders

    Science.gov (United States)

    We examined the effects of a food spray mixture (‘wheast’) and its individual ingredients (sucrose, yeast, and toasted soy flour) on the survivorship, growth, and development of a cursorial spider, Hibana futilis Banks (Anyphaenidae). Some treatments included eggs of Helicoverpa zea, a favored prey...

  1. Searching responses of a hunting spider to cues associated with lepidopteran eggs

    Science.gov (United States)

    Cheiracanthium inclusum (Hentz), a cursorial spider, has been frequently observed feeding on the eggs of Helicoverpa zea (Boddie), an important cotton pest. This study investigated whether compounds present in H. zea scales and egg residues could act as kairomones and be used by C. inclusum in its ...

  2. Integration of biological control and transgenic insect protection for mitigation of mycotoxins in corn

    Science.gov (United States)

    Biological control is known to be effective in reducing aflatoxin contamination of corn and some transgenic corn hybrids incur greatly reduced damage from corn earworm (Helicoverpa zea). We conducted seven field trials over two years to test the hypothesis that transgenic insect protection and biol...

  3. Toxicity of five forest insecticides to cutthroat trout and two species of aquatic invertebrates

    Science.gov (United States)

    Woodward, D.F.; Mauck, W.L.

    1980-01-01

    The Northern Rocky Mountain region has had scattered infestation of the western spruce budworm Christoneura occidentalis since the early 1900's (U.S. DEPARTMENT OF AGRICULTURE (USDA) 1976b). On the basis of aerial surveys in 1975, TUNNOCK et al. (1976), estimated that budworm defoliation occurred on 2,278,804 acres of six National Forests in Montana. Since the use of DDT was banned in 1972, there has been a need to develop alternative insecticides with the efficacy of DDT but without its environmental risk. These insecticides must be effective in controlling the budworm, but should not persist in the environment or be toxic to other organisms. The organophosphate and carbamate insecticides are relatively nonpersistent and generally present only a moderate hazard to fish when applied according to label recommendations. The USDA Forest Service has been investigating the effectiveness of these two classes of insecticides against the budworm, and the Columbia National Fisheries Research Laboratory of the U.S. Fish and Wildlife Service has been cooperating with the Forest Service conducted pilot control projects in eastern Montana in 1975 and 1976 to determine the efficacy and environmental impact of acephate, carbaryl, and trichlorfon in controlling the western budworm (USDA 1976 b). In 1975, a similar type project was carried out in Maine with aminocarb, fenitrothion, and trichlorfon (USDA 1976 a).Acephate, fenitrothion, and trichlorfon (organophosphate insecticides) and aminocarb and carbaryl (carbamate insecticides) were selected for toxicity tests against cutthroat trout (Salmo clarki), a stonefly (Pteronarcella badia), and a freshwater amphipod (Gammarus pseudolimnaeus) edemic in streams of the northern Rocky Mountains. Populations of cutthroat trout inhabit lakes and streams in the Rocky Mountains which include some of the most pristine habitat and fisheries in North America. Pteronarcella and Gammarus provide forage for cutthroat trout and feed on decaying

  4. 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.

  5. 2678-IJBCS-Article-Abla Dela Mondedji

    African Journals Online (AJOL)

    hp

    l'envahissement de la flore forestière togolaise par les espèces végétales exotiques : cas du neem (Azadirachta indica). Mémoire de D.E.A., Université de Lomé, 61p. Kranthi KR, Jadhav D, Wanjari R, Kranrhi S,. Russel D. 2001. Pyrethroid resistance and mechanisms of resistance in field strains of Helicoverpa armigera.

  6. Transmission of Different Nucleopolyhedroviruses by Two Ectoparasitoids – Bracon hebetor Say (Hymenoptera: Braconidae) and Euplectrus plathypenae (Howard) (Hymenoptera: Eulophidae)

    OpenAIRE

    Emanouela E. Stoianova; Nikolay A. Balevski

    2010-01-01

    The transmission of nucleopolyhedroviruses (NPVs) of Autographa gamma (AgNPV), Mamestra brassicae (MbNPV), Lacanobia oleraceae (LoNPV), Helicoverpa armigera (HaNPV) and Xantia c-nigrum (XnNPV) to their relevant larvae by the ectoparasitoid Bracon hebetor and the transmission of the multiple-enveloped NPVs of Spodoptera exigua (SeMNPV) and Spodoptera frugiperda (SfMNPV) by the ectoparasitoid Euplectrus plathypenae was examined. Two methods of contamination of the both parasitoids (exposure to ...

  7. Reduced plant nutrition under elevated CO2 depresses the immunocompetence of cotton bollworm against its endoparasite

    OpenAIRE

    Yin, Jin; Sun, Yucheng; Ge, Feng

    2014-01-01

    Estimating the immunocompetence of herbivore insects under elevated CO2 is an important step in understanding the effects of elevated CO2 on crop-herbivore-natural enemy interactions. Current study determined the effect of elevated CO2 on the immune response of Helicoverpa armigera against its parasitoid Microplitis mediator. H. armigera were reared in growth chambers with ambient or elevated CO2, and fed wheat grown in the concentration of CO2 corresponding to their treatment levels. Our res...

  8. Des pratiques culturales influent sur les attaques de deux ravageurs ...

    African Journals Online (AJOL)

    La culture de tomate est attaquée par plusieurs ravageurs dont Helicoverpa armigera et Tuta absoluta. Dans le but d'évaluer l'effet des pratiques culturales de la tomate sur ces principaux ravageurs dans les Niayes (Sénégal), un échantillonnage de 98 parcelles est effectué, sur quatre cycles de culture en saison sèche, de ...

  9. 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)

  10. EVALUATION OF FOUR INTEGRATED PEST MANAGEMENT PACKAGES FOR CONTROLLING MAIN PESTS OF COTTON IN RAINFED FIELDS

    OpenAIRE

    Nurindah Nurindah; Dwi Adi Sunarto

    2014-01-01

    Cotton production nationally is low due to various constraints, including pests. Two main pests commonly found in cotton plantation in rain fed fields are cotton leafhopper (Amrasca biguttula) and cotton bollworm (Helicoverpa armigera). The study aimed to evaluate four packages of integrated pest management (IPM) techniques to control cotton leafhopper and cotton bollworm in rain fed fields. The experiment was conducted in farmers’ fields at Asembagus, East Java, between January and July 2012...

  11. Forest pest conditions in the maritimes in 1992. Information report No. M-X-183E. Annual publication

    Energy Technology Data Exchange (ETDEWEB)

    Magasi, L.P.; Cormier, J.R.

    1993-01-01

    Review of the status of forest insects and diseases in the Maritimes Region in 1992, along with forecast conditions for 1993 when appropriate. Describes pests and problems of conifers, hardwoods, and high value areas such as nurseries, seed orchards, plantations, and Christmas tree areas and summarizes control operations against spruce budworm and Sirococcus shoot blight. A chapter on forest health monitoring brings together the various aspects of work dealing with changes in forest conditions. Forest insect monitoring systems, such as pheromones and light traps, are briefly described. A list of reports and publications relating to forest pest conditions is included.

  12. Forest pest conditions in the maritimes in 1991. Information report No. M-X-181E. Annual publication

    Energy Technology Data Exchange (ETDEWEB)

    Magasi, L.P.

    1992-01-01

    This report reviews the status of forest insects and diseases in the Maritimes region in 1991 and forecasts conditions for 1992, when appropriate. Pests and problems of conifers, hardwoods, and high-value areas, such as nurseries, seed orchards, plantations, and Christmas tree areas, are described as observed in 1991. Control operations against spruce budworm, hemlock looper, and Sirococcus shoot blight are summarized. A section on forest health monitoring brings together the various aspects of work dealing with changes in forest conditions, some of which are still unexplained. Forest insect monitoring systems, pheromones, and light traps are briefly described. A list of reports and publications relating to forest pest conditions is included.

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

    Directory of Open Access Journals (Sweden)

    Roberto Quezada-Garcia

    2015-01-01

    Full Text Available 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.

  14. 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

    2015-02-16

    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.

  15. High Tensile Strength of Engineered β-Solenoid Fibrils via Sonication and Pulling.

    Science.gov (United States)

    Peng, Zeyu; Parker, Amanda S; Peralta, Maria D R; Ravikumar, Krishnakumar M; Cox, Daniel L; Toney, Michael D

    2017-11-07

    We present estimates of ultimate tensile strength (UTS) for two engineered β-solenoid protein mutant fibril structures (spruce budworm and Rhagium inquisitor antifreeze proteins) derived from sonication-based measurements and from force pulling molecular dynamics simulations, both in water. Sonication experiments generate limiting scissioned fibrils with a well-defined length-to-width correlation for the mutant spruce budworm protein and the resultant UTS estimate is 0.66 ± 0.08 GPa. For fibrils formed from engineered R. inquisitor antifreeze protein, depending upon geometry, we estimate UTSs of 3.5 ± 3.2-5.5 ± 5.1 GPa for proteins with interfacial disulfide bonds, and 1.6 ± 1.5-2.5 ± 2.3 GPa for the reduced form. The large error bars for the R. inquisitor structures are intrinsic to the broad distribution of limiting scission lengths. Simulations provide pulling velocity-dependent UTSs increasing from 0.2 to 1 GPa in the available speed range, and 1.5 GPa extrapolated to the speeds expected in the sonication experiments. Simulations yield low-velocity values for the Young's modulus of 6.0 GPa. Without protein optimization, these mechanical parameters are similar to those of spider silk and Kevlar, but in contrast to spider silk, these proteins have a precisely known sequence-structure relationship. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  16. PRODUCT NEEM AZAL T/S - BROAD-SPECTRUM PHYPOPESTICIDE FOR CONTROL OF PESTS ON VEGETABLE CROPS

    Directory of Open Access Journals (Sweden)

    Vinelina Yankova

    2016-09-01

    Full Text Available Experiments for determination of the effectiveness of product Neem Azal T/S (a. i. azadirachtin were conducted at a concentration of 0,3% against some major pests in vegetable crops grown in greenhouses at the Maritsa Vegetable Crops research Institute, Plovdiv during the period 2010-2016. It was established very good insecticidal and acaricidal action of phytopesticide against: cotton aphid (Aphis gossypii Glov.; green peach aphid (Myzus persicae Sulz.; western flower trips (Frankliniella occidentalis Perg.; cotton bollworm (Helicoverpa armigera Hubn.; tomato borer (Tuta absoluta Meyrick and two-spotted spider mite (Tetranichus urticae Koch.. This product is a successful alternative to using chemical insecticides and acaricides.

  17. In vivo function of Pgβglu-1 in the release of acetophenones in white spruce

    Directory of Open Access Journals (Sweden)

    Melissa H. Mageroy

    2017-07-01

    Full Text Available Eastern spruce budworm (Choristoneura fumiferiana Clemens (ESBW is a major forest pest which feeds on young shoots of white spruce (Picea glauca and can cause landscape level economic and ecological losses. Release of acetophenone metabolites, piceol and pungenol, from their corresponding glycosides, picein and pungenin, can confer natural resistance of spruce to ESBW. A beta-glucosidase gene, Pgβglu-1, was recently discovered and the encoded enzyme was characterized in vitro to function in the release of the defensive acetophenone aglycons. Here we describe overexpression of Pgβglu-1 in a white spruce genotype whose metabolome contains the glucosylated acetophenones, but no detectable amounts of the aglycons. Transgenic overexpression of Pgβglu-1 resulted in release of the acetophenone aglycons in planta. This work provides in vivo evidence for the function of Pgβglu-1.

  18. Environmental problem-solving: Psychosocial factors

    Science.gov (United States)

    Miller, Alan

    1982-11-01

    This is a study of individual differences in environmental problem-solving, the probable roots of these differences, and their implications for the education of resource professionals. A group of student Resource Managers were required to elaborate their conception of a complex resource issue (Spruce Budworm management) and to generate some ideas on management policy. Of particular interest was the way in which subjects dealt with the psychosocial aspects of the problem. A structural and content analysis of responses indicated a predominance of relatively compartmentalized styles, a technological orientation, and a tendency to ignore psychosocial issues. A relationship between problem-solving behavior and personal (psychosocial) style was established which, in the context of other evidence, suggests that problem-solving behavior is influenced by more deep seated personality factors. The educational implication drawn was that problem-solving cannot be viewed simply as an intellectual-technical activity but one that involves, and requires the education of, the whole person.

  19. Solution Structure of an Antifreeze Protein CfAFP-501 from Choristoneura fumiferana

    International Nuclear Information System (INIS)

    Li Congmin; Guo Xianrong; Jia Zongchao; Xia Bin; Jin Changwen

    2005-01-01

    Antifreeze proteins (AFPs) are widely employed by various organisms as part of their overwintering survival strategy. AFPs have the unique ability to suppress the freezing point of aqueous solution and inhibit ice recrystallization through binding to the ice seed crystals and restricting their growth. The solution structure of CfAFP-501 from spruce budworm has been determined by NMR spectroscopy. Our result demonstrates that CfAFP-501 retains its rigid and highly regular structure in solution. Overall, the solution structure is similar to the crystal structure except the N- and C-terminal regions. NMR spin-relaxation experiments further indicate the overall rigidity of the protein and identify a collection of residues with greater flexibilities. Furthermore, Pro91 shows a cis conformation in solution instead of the trans conformation determined in the crystal structure

  20. An algorithm for engineering regime shifts in one-dimensional dynamical systems

    Science.gov (United States)

    Tan, James P. L.

    2018-01-01

    Regime shifts are discontinuous transitions between stable attractors hosting a system. They can occur as a result of a loss of stability in an attractor as a bifurcation is approached. In this work, we consider one-dimensional dynamical systems where attractors are stable equilibrium points. Relying on critical slowing down signals related to the stability of an equilibrium point, we present an algorithm for engineering regime shifts such that a system may escape an undesirable attractor into a desirable one. We test the algorithm on synthetic data from a one-dimensional dynamical system with a multitude of stable equilibrium points and also on a model of the population dynamics of spruce budworms in a forest. The algorithm and other ideas discussed here contribute to an important part of the literature on exercising greater control over the sometimes unpredictable nature of nonlinear systems.

  1. Insect-induced tree mortality of boreal forests in eastern Canada under a changing climate.

    Science.gov (United States)

    Zhang, Xiongqing; Lei, Yuancai; Ma, Zhihai; Kneeshaw, Dan; Peng, Changhui

    2014-06-01

    Forest insects are major disturbances that induce tree mortality in eastern coniferous (or fir-spruce) forests in eastern North America. The spruce budworm (SBW) (Choristoneura fumiferana [Clemens]) is the most devastating insect causing tree mortality. However, the relative importance of insect-caused mortality versus tree mortality caused by other agents and how this relationship will change with climate change is not known. Based on permanent sample plots across eastern Canada, we combined a logistic model with a negative model to estimate tree mortality. The results showed that tree mortality increased mainly due to forest insects. The mean difference in annual tree mortality between plots disturbed by insects and those without insect disturbance was 0.0680 per year (P eastern Canada but that tree mortality induced by insect outbreaks will decrease in eastern Canada under warming climate.

  2. 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.

  3. Response of breeding birds to aerial sprays of trichlorfon (Dylox) and carbaryl (Sevin-4-Oil) in Montana forests

    Science.gov (United States)

    DeWeese, L.R.; Henny, C.J.; Floyd, R.L.; Bobal, K.A.; Schultz, A.W.

    1979-01-01

    Breeding density, food, nesting success, and mortality of 20 bird species were monitored at Beaverhead National Forest, Montana, in 1975 in conjunction with experimental applications of trichlorfon (Dylox) and carbaryl (Sevin-4-oil) to western budworms (Choristoneura occidentalis). Bird species on nine 350- to 550-ha forested plots (three controls and three treated with each pesticide) were studied before and for 14 days after the spraying of trichlorfon at 1.1 kg in?9.4 L of Panasol AN3 per ha (1 pound active ingredient in 1.0 gallon/acre) and of carbaryl at 1.1 kg in 4.7 L of diesel oil per ha (l pound active ingredient in 0.5 gallon/acre). No significant decrease in bird numbers was detected from breeding-pair estimates or live bird counts after the spraying. Of the breeding pairs present before spraying, 92% remained on control plots, 89% on trichlorfon plots, and 92% on carbaryl plots. Counts of live birds made before and after spraying in three types of habitat supported the. results of the breeding-pair estimates. Nests with eggs or with young at the time of spraying were 74 and 97% successful, respectively, in control plots, 83 and 100% in plots sprayed with trichlorfon, and 86 and 100% in plots sprayed with carbaryl. No sick or dead birds were found after the spraying, although budworms were found in bird stomachs, and tracer-dye from the pesticide occurred on the feathers or feet of 74% of the 202 birds collected. Species dwelling in the tree canopy encountered the dye (and thus the pesticide) at a slightly higher rate (80%) than did species below the treetops (71 %) or near the ground and in open areas (70%).

  4. Recent advances of rearing cabinet instrumentation and control system for insect stock culture

    Science.gov (United States)

    Hermawan, Wawan; Kasmara, Hikmat; Melanie, Panatarani, Camellia; Joni, I. Made

    2017-01-01

    Helicoverpa armigera (Hubner) is one of a serious pest of horticulture in Indonesia. Helicoverpa armigera Nuclear Polyhedrovirus (HaNPV) has attracted interest for many researchers as a pest control for larvae of this species. Currently, we investigating the agrochemical formulations of HaNPV by introducing nanotechnology. Thus it is required an acceptable efficiency of insect stock cultures equipped with advance instruments to resolve the difficulties on insect stock seasons dependency. In addition, it is important to improve the insect survival with the aid of artificial natural environment and gain high insect production. This paper reports the rearing cabinet used as preparation of stock culture includes air-conditioning system, lighting, i.e. day and night control, and the main principles on recent technical and procedural advances apparatus of the system. The rearing system was moveable, designed and build by allowing air-conditioned cabinet for rearing insects, air motion and distribution as well as temperature and humidity being precisely controlled. The air was heated, humidified, and dehumidified respectively using a heater and ultrasonic nebulizer as actuators. Temperature and humidity can be controlled at any desired levels from room temperature (20°C) to 40 ± 1°C and from 0 to 80% RH with an accuracy of ±3% R.H. It is concluded that the recent design has acceptable performance based on the defined requirement for insect rearing and storage.

  5. In-silico determination of insecticidal potential of Vip3Aa-Cry1Ac fusion protein against Lepidopteran targets using molecular docking

    Directory of Open Access Journals (Sweden)

    Aftab eAhmad

    2015-12-01

    Full Text Available Study and research of Bt (Bacillus thuringiensis transgenic plants have opened new ways to combat insect pests. Over the decades, however, insect pests, especially the Lepidopteran, have developed tolerance against Bt delta-endotoxins. Such issues can be addressed through the development of novel toxins with greater toxicity and affinity against a broad range of insect receptors. In this computational study, functional domains of Bacillus thuringiensis crystal delta-endotoxin (Cry1Ac insecticidal protein and vegetative insecticidal protein (Vip3Aa have been fused to develop a broad-range Vip3Aa-Cry1Ac fusion protein. Cry1Ac and Vip3Aa are non-homologous insecticidal proteins possessing receptors against different targets within the midgut of insects. The insecticidal proteins were fused to broaden the insecticidal activity. Molecular docking analysis of the fusion protein against aminopeptidase-N (APN and cadherin receptors of five Lepidopteran insects (Agrotis ipsilon, Helicoverpa armigera, Pectinophora gossypiella, Spodoptera exigua and Spodoptera litura revealed that the Ser290, Ser293, Leu337, Thr340 and Arg437 residues of the fusion protein are involved in the interaction with insect receptors. The Helicoverpa armigera cadherin receptor, however, showed no interaction, which might be due to either loss or burial of interactive residues inside the fusion protein. These findings revealed that the Vip3Aa-Cry1Ac fusion protein has a strong affinity against Lepidopteran insect receptors and hence has a potential to be an efficient broad-range insecticidal protein.

  6. Diversity and abundance of lepidopteran populations from selected crops of district faisalabad, pakistan

    International Nuclear Information System (INIS)

    Maalik, S.; Rana, S.A.; Khan, H.A.; Ashfaq, M.

    2012-01-01

    Lepidopterans are represented by one of the most diverse group of insects. They are phytophagous as well as pollinators at the same time. During present study four crops i.e Wheat, Fodder, Brassica and Vegetables were sampled to assess the diversity and abundance of Lepidopteran populations. A total of 2811 specimens belonging to 14 species and 6 families were recorded. Pieris brassicae (29.46%) was the dominant species followed by Trichoplusia ni (19.28%), Helicoverpa Zea (11.78%), Helicoverpa armigera (11.60%), Spodoptera exigua (6.65%), Psedoplusia includes (5.09%), Spodoptera litura (3.81%), Agrotis ipsilon (4.87%), Plutella xylostella (2.92%), Lymatria dispar (2.24%), Pieris rapae (0.92%), Galleria mellonella (0.71%), Evergestris rimosalis (0.53%) and Menduca sexta (0.14%). Significant differences were observed among different crops by applying Shannon Diversity Index and T- test. CA (Cluster analysis) represented the species association with different crops. Majority of the species showed association with Vegetables and Fodder and least association was observed with Wheat. Such types of studies are necessary to design integrated pest management programs to control these pests. (author)

  7. in silico identification of cross affinity towards Cry1Ac pesticidal protein with receptor enzyme in Bos taurus and sequence, structure analysis of crystal proteins for stability.

    Science.gov (United States)

    Ebenezer, King Solomon; Nachimuthu, Ramesh; Thiagarajan, Prabha; Velu, Rajesh Kannan

    2013-01-01

    Any novel protein introduced into the GM crops need to be evaluated for cross affinity on living organisms. Many researchers are currently focusing on the impact of Bacillus thuringiensis cotton on soil and microbial diversity by field experiments. In spite of this, in silico approach might be helpful to elucidate the impact of cry genes. The crystal a protein which was produced by Bt at the time of sporulation has been used as a biological pesticide to target the insectivorous pests like Cry1Ac for Helicoverpa armigera and Cry2Ab for Spodoptera sp. and Heliothis sp. Here, we present the comprehensive in silico analysis of Cry1Ac and Cry2Ab proteins with available in silico tools, databases and docking servers. Molecular docking of Cry1Ac with procarboxypeptidase from Helicoverpa armigera and Cry1Ac with Leucine aminopeptidase from Bos taurus has showed the 125(th) amino acid position to be the preference site of Cry1Ac protein. The structures were compared with each other and it showed 5% of similarity. The cross affinity of this toxin that have confirmed the earlier reports of ill effects of Bt cotton consumed by cattle.

  8. Climate change, transgenic corn adoption and field-evolved resistance in corn earworm.

    Science.gov (United States)

    Venugopal, P Dilip; Dively, Galen P

    2017-06-01

    Increased temperature anomaly during the twenty-first century coincides with the proliferation of transgenic crops containing the bacterium Bacillus thuringiensis (Berliner) (Bt) to express insecticidal Cry proteins. Increasing temperatures profoundly affect insect life histories and agricultural pest management. However, the implications of climate change on Bt crop-pest interactions and insect resistance to Bt crops remains unexamined. We analysed the relationship of temperature anomaly and Bt adoption with field-evolved resistance to Cry1Ab Bt sweet corn in a major pest, Helicoverpa zea (Boddie). Increased Bt adoption during 1996-2016 suppressed H. zea populations, but increased temperature anomaly buffers population reduction. Temperature anomaly and its interaction with elevated selection pressure from high Bt acreage probably accelerated the Bt-resistance development. Helicoverpa zea damage to corn ears, kernel area consumed, mean instars and proportion of late instars in Bt varieties increased with Bt adoption and temperature anomaly, through additive or interactive effects. Risk of Bt-resistant H. zea spreading is high given extensive Bt adoption, and the expected increase in overwintering and migration. Our study highlights the challenges posed by climate change for Bt biotechnology-based agricultural pest management, and the need to incorporate evolutionary processes affected by climate change into Bt-resistance management programmes.

  9. Genetically pyramiding protease-inhibitor genes for dual broad-spectrum resistance against insect and phytopathogens in transgenic tobacco.

    Science.gov (United States)

    Senthilkumar, Rajendran; Cheng, Chiu-Ping; Yeh, Kai-Wun

    2010-01-01

    Protease inhibitors provide a promising means of engineering plant resistance against attack by insects and pathogens. Sporamin (trypsin inhibitor) from sweet potato and CeCPI (phytocystatin) from taro were stacked in a binary vector, using pMSPOA (a modified sporamin promoter) to drive both genes. Transgenic tobacco lines of T0 and T1 generation with varied inhibitory activity against trypsin and papain showed resistance to both insects and phytopathogens. Larvae of Helicoverpa armigera that ingested tobacco leaves either died or showed delayed growth and development relative to control larvae. Transgenic tobacco-overexpressing the stacked genes also exhibited strong resistance against bacterial soft rot disease caused by Erwinia carotovora and damping-off disease caused by Pythium aphanidermatum. Thus, stacking protease-inhibitor genes, driven by the wound and pathogen responsive pMSPOA promoter, is an effective strategy for engineering crops to resistance against insects and phytopathogens.

  10. Screening of broad spectrum natural pesticides against conserved target arginine kinase in cotton pests by molecular modeling.

    Science.gov (United States)

    Sakthivel, Seethalakshmi; Habeeb, S K M; Raman, Chandrasekar

    2018-03-12

    Cotton is an economically important crop and its production is challenged by the diversity of pests and related insecticide resistance. Identification of the conserved target across the cotton pest will help to design broad spectrum insecticide. In this study, we have identified conserved sequences by Expressed Sequence Tag profiling from three cotton pests namely Aphis gossypii, Helicoverpa armigera, and Spodoptera exigua. One target protein arginine kinase having a key role in insect physiology and energy metabolism was studied further using homology modeling, virtual screening, molecular docking, and molecular dynamics simulation to identify potential biopesticide compounds from the Zinc natural database. We have identified four compounds having excellent inhibitor potential against the identified broad spectrum target which are highly specific to invertebrates.

  11. Analysis of variation in virulence of Beauveria bassiana against insect pests of pigeonpea using qPCR.

    Science.gov (United States)

    Senthilraja, Govindasamy; Anand, Theerthagiri; Mohankumar, Subbarayalu; Raguchander, Thiruvengadam; Samiyappan, Ramasamy

    2018-03-01

    Beauveria bassiana is a broad spectrum microbial bioagent used for the control of agriculturally important insect pests. However, in our experiments, two virulent isolates of B. bassiana (B2 and B10) showed specific preference toward Maruca vitrata and Helicoverpa armigera of pigeonpea. To better understand this feature, we developed a qPCR assay to quantify the chitinase (virulence factor) of B. bassiana during the infection process. Isolates of B. bassiana were grown on insect cuticle amended medium and minimal medium (without insect cuticle) to assess the induction of chitinase. Our results revealed a positive correlation between expression of chitinase by B. bassiana and the substrates (with or without cuticles of M. vitrata and H. armigera) used. This study showcases the methodology to quantify the chitinase and analysis of variation in virulence of B. bassiana (B2 and B10) against M. vitrata and H. armigera. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. 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.

  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. Design, Synthesis, and Insecticidal Activity of Some Novel Diacylhydrazine and Acylhydrazone Derivatives

    Directory of Open Access Journals (Sweden)

    Jialong Sun

    2015-03-01

    Full Text Available In this study a series of diacylhydrazine and acylhydrazone derivatives were designed and synthesized according to the method of active group combination and the principles of aromatic group bioisosterism. The structures of the novel derivatives were determined on the basis on 1H-NMR, IR and ESI-MS spectral data. All of the compounds were evaluated for their in vivo insecticidal activity against the third instar larvae of Spodoptera exigua Hiibner, Helicoverpa armigera Hubner, Plutella xyllostella Linnaeus and Pieris rapae Linne, respectively, at a concentration of 10 mg/L. The results showed that all of the derivatives displayed high insecticidal activity. Most of the compounds presented higher insecticidal activity against S. exigua than the reference compounds tebufenozide, metaflumizone and tolfenpyrad, and approximately identical insecticidal activity against H. armigera, P. xyllostella and P. rapae as the references metaflumizone and tolfenpyrad.

  15. Safety assessment and detection method of genetically modified Chinese Kale (Brassica oleracea cv. alboglabra ).

    Science.gov (United States)

    Lin, Chih-Hui; Lu, Chien-Te; Lin, Hsin-Tang; Pan, Tzu-Ming

    2009-03-11

    Sporamins are tuberous storage proteins and account for 80% of soluble protein in sweet potato tubers with trypsin-inhibitory activity. The expression of sporamin protein in transgenic Chinese kale (line BoA 3-1) conferred insecticidal activity toward corn earworm [ Helicoverpa armigera (Hubner)] in a previous report. In this study, we present a preliminary safety assessment of transgenic Chinese kale BoA 3-1. Bioinformatic and simulated gastric fluid (SGF) analyses were performed to evaluate the allergenicity of sporamin protein. The substantial equivalence between transgenic Chinese kale and its wild-type host has been demonstrated by the comparison of important constituents. A reliable real-time polymerase chain reaction (PCR) detection method was also developed to control sample quality. Despite the results of most evaluations in this study being negative, the safety of sporamin in transgenic Chinese kale BoA 3-1 was uncluded because of the allergenic risk revealed by bioinformatic analysis.

  16. 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. © The Author 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. 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.

  18. Cloning and characterization of the pheromone biosynthesis activating neuropeptide receptor gene in Spodoptera littoralis larvae.

    Science.gov (United States)

    Zheng, Lei; Lytle, Christian; Njauw, Ching-Ni; Altstein, Miriam; Martins-Green, Manuela

    2007-05-15

    In noctuid moths cuticular pigmentation is regulated by the pyrokinin/pheromone biosynthesis activating neuropeptide (PK/PBAN) family, which also mediates a variety of other functions in moths and other insects. Numerous studies have shown that these neuropeptides exert their functions through activation of the PBAN receptor (PBAN-R), with subsequent Ca(2+) influx, followed by either activation of cAMP or direct activation of downstream kinases. Recently, several PBAN-Rs have been identified, all of which are from the pheromone gland of adult female moths, but evidence shows that functional PK/PBAN-Rs can also be expressed in insect larvae, where they mediate melanization and possibly other functions (e.g., diapause). Here, we identified a gene encoding a G-protein-coupled receptor from the 5th instar larval tissue of the moth Spodoptera littoralis. The cDNA of this gene contains an open reading frame with a length of 1050 nucleotides, which translates to a 350-amino acid, 42-kDa protein that shares 92% amino acid identity with Helicoverpa zea and Helicoverpa armigera PBAN-R, 81% with Bombyx mori PBAN-R and 72% with Plutella xylostella PBAN-R. The S. littoralis PBAN-R gene was stably expressed in NIH3T3 cells and transiently in HEK293 cells. We show that it mediates the dose-dependent PBAN-induced intracellular Ca(2+) response and activation of the MAP kinase via a PKC-dependent but Galphai-independent signaling mechanism. Other PK/PBAN family peptides (pheromonotropin and a C-terminally PBAN-derived peptide PBAN(28-33)NH(2)) also triggered MAP kinase activation. This receptor, together with the previously cloned PBAN-R, may facilitate our understanding of the cell-specific responses and functional diversities of this diverse neuropeptide family.

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

    Science.gov (United States)

    Smith, M Alex; Eveleigh, Eldon S; McCann, Kevin S; Merilo, Mark T; McCarthy, Peter C; Van Rooyen, Kathleen I

    2011-01-01

    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 future budworm

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

    International Nuclear Information System (INIS)

    LaChance, L.E.; Graham, C.K.

    1984-01-01

    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. (Auth.)

  2. Genes, enzymes and chemicals of terpenoid diversity in the constitutive and induced defence of conifers against insects and pathogens.

    Science.gov (United States)

    Keeling, Christopher I; Bohlmann, Jörg

    2006-01-01

    Insects select their hosts, but trees cannot select which herbivores will feed upon them. Thus, as long-lived stationary organisms, conifers must resist the onslaught of varying and multiple attackers over their lifetime. Arguably, the greatest threats to conifers are herbivorous insects and their associated pathogens. Insects such as bark beetles, stem- and wood-boring insects, shoot-feeding weevils, and foliage-feeding budworms and sawflies are among the most devastating pests of conifer forests. Conifer trees produce a great diversity of compounds, such as an enormous array of terpenoids and phenolics, that may impart resistance to a variety of herbivores and microorganisms. Insects have evolved to specialize in resistance to these chemicals -- choosing, feeding upon, and colonizing hosts they perceive to be best suited to reproduction. This review focuses on the plant-insect interactions mediated by conifer-produced terpenoids. To understand the role of terpenoids in conifer-insect interactions, we must understand how conifers produce the wide diversity of terpenoids, as well as understand how these specific compounds affect insect behaviour and physiology. This review examines what chemicals are produced, the genes and proteins involved in their biosynthesis, how they work, and how they are regulated. It also examines how insects and their associated pathogens interact with, elicit, and are affected by conifer-produced terpenoids.

  3. 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.

  4. Systemic Imidacloprid Affects Intraguild Parasitoids Differently

    Science.gov (United States)

    Roe, R. Michael; Bacheler, Jack S.

    2015-01-01

    Toxoneuron nigriceps (Viereck) (Hymenoptera, Braconidae) and Campoletis sonorensis (Cameron) (Hymenoptera, Ichneumonidae) are solitary endoparasitoids of the tobacco budworm, Heliothis virescens (Fabricius) (Lepidoptera, Noctuidae). They provide biological control of H. virescens populations in Southeastern US agricultural production systems. Field and greenhouse experiments conducted from 2011–2014 compared parasitism rates of parasitoids that developed inside H. virescens larvae fed on tobacco plants treated with and without imidacloprid. The parasitoids in our study did not have a similar response. Toxoneuron nigriceps had reduced parasitism rates, but parasitism rates of C. sonorensis were unaffected. Preliminary data indicate that adult female lifespans of T. nigriceps are also reduced. ELISA was used to measure concentrations of neonicotinoids, imidacloprid and imidacloprid metabolites in H. virescens larvae that fed on imidacloprid-treated plants and in the parasitoids that fed on these larvae. Concentrations were detectable in the whole bodies of parasitized H. virescens larvae, T. nigriceps larvae and T. nigriceps adults, but not in C. sonorensis larvae and adults. These findings suggest that there are effects of imidacloprid on multiple trophic levels, and that insecticide use may differentially affect natural enemies with similar feeding niches. PMID:26658677

  5. Systemic Imidacloprid Affects Intraguild Parasitoids Differently.

    Directory of Open Access Journals (Sweden)

    Sally V Taylor

    Full Text Available Toxoneuron nigriceps (Viereck (Hymenoptera, Braconidae and Campoletis sonorensis (Cameron (Hymenoptera, Ichneumonidae are solitary endoparasitoids of the tobacco budworm, Heliothis virescens (Fabricius (Lepidoptera, Noctuidae. They provide biological control of H. virescens populations in Southeastern US agricultural production systems. Field and greenhouse experiments conducted from 2011-2014 compared parasitism rates of parasitoids that developed inside H. virescens larvae fed on tobacco plants treated with and without imidacloprid. The parasitoids in our study did not have a similar response. Toxoneuron nigriceps had reduced parasitism rates, but parasitism rates of C. sonorensis were unaffected. Preliminary data indicate that adult female lifespans of T. nigriceps are also reduced. ELISA was used to measure concentrations of neonicotinoids, imidacloprid and imidacloprid metabolites in H. virescens larvae that fed on imidacloprid-treated plants and in the parasitoids that fed on these larvae. Concentrations were detectable in the whole bodies of parasitized H. virescens larvae, T. nigriceps larvae and T. nigriceps adults, but not in C. sonorensis larvae and adults. These findings suggest that there are effects of imidacloprid on multiple trophic levels, and that insecticide use may differentially affect natural enemies with similar feeding niches.

  6. 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.

  7. 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.

  8. Combined action of sex pheromone and wasp Apanteles gelechiidivoris in greenhouse Tomato crops

    International Nuclear Information System (INIS)

    Morales, Jessica; Munoz, Laura; Rodriguez, Daniel; Cantor, Fernando

    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 including biological control with A. gelechiidivoris, ethological control with sexual pheromone traps, and 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.

  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

    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

  10. Comparative evaluation of phenoloxidase activity in different larval stages of four lepidopteran pests after exposure to Bacillus thuringiensis.

    Science.gov (United States)

    Valadez-Lira, J A; Alcocer-Gonzalez, J M; Damas, G; Nuñez-Mejía, G; Oppert, B; Rodriguez-Padilla, C; Tamez-Guerra, P

    2012-01-01

    Microbial entomopathogen-based bioinsecticides are recognized as alternatives to synthetic pesticides. Insects defend themselves against microbial pathogens by innate mechanisms, including increased phenoloxidase (PO) activity, but its relationship with microbial bioinsecticides efficacy is little known. This study evaluated the differences in PO activity at different developmental stages of the tobacco budworm Heliothis virescens Fabricius (Lepidoptera: Noctuidae), Indian meal moth Plodia interpunctella (Hübner) (Pyralidae), beet armyworm Spodoptera exigua (Hübner) (Noctuidae), and cabbage looper Trichoplusia ni (Hübner) (Noctuidae). Additionally, 2(nd)- and 4(th)-instars were exposed to the LC(50) value of the commercial Bacillus thuringiensis (Bt) spray, Biobit(®). The percentage of insecticidal activity (IA%) on 2(nd)-instar Biobit-exposed larvae was approximately the predicted 50 % mortality for all species except S. exigua. With all 4(th) instar Biobit-exposed larvae, mortality was not significantly different from that of unexposed larvae. Unexposed insects had a significantly higher PO activity in pre-pupae and pupae than early-instar larvae and adults, whereas PO activity was higher in adult females than in males. Correlation analysis between IA% and PO activity revealed significant r-values (p < 0.01) in 2(nd) instar H. virescens (r = 0.979) and P. interpunctella (r = 0.930). Second instar Biobit-exposed P. interpunctella had 10 times more PO activity than unexposed larvae. Similarly, the amount of total protein was lower in 4(th) instar Biobit-exposed H. virescens and higher in S. exigua. Therefore, the results indicated a relationship between Biobit susceptibility and PO activity in some cases. This information may be useful if the Biobit application period is timed for a developmental stage with low PO activity. However, more studies are needed to determine the correlation of each insect with a particular bioinsecticide.

  11. Decadal-scale ecosystem memory reveals interactive effects of drought and insect defoliation on boreal forest productivity

    Science.gov (United States)

    Itter, M.; D'Orangeville, L.; Dawson, A.; Kneeshaw, D.; Finley, A. O.

    2017-12-01

    Drought and insect defoliation have lasting impacts on the dynamics of the boreal forest. Impacts are expected to worsen under global climate change as hotter, drier conditions forecast for much of the boreal increase the frequency and severity of drought and defoliation events. Contemporary ecological theory predicts physiological feedbacks in tree responses to drought and defoliation amplify impacts potentially causing large-scale productivity losses and forest mortality. Quantifying the interactive impacts of drought and insect defoliation on regional forest health is difficult given delayed and persistent responses to disturbance events. We developed a Bayesian hierarchical model to estimate forest growth responses to interactions between drought and insect defoliation by species and size class. Delayed and persistent responses to past drought and defoliation were quantified using empirical memory functions allowing for improved detection of interactions. The model was applied to tree-ring data from stands in Western (Alberta) and Eastern (Québec) regions of the Canadian boreal forest with different species compositions, disturbance regimes, and regional climates. Western stands experience chronic water deficit and forest tent caterpillar (FTC) defoliation; Eastern stands experience irregular water deficit and spruce budworm (SBW) defoliation. Ecosystem memory to past water deficit peaked in the year previous to growth and decayed to zero within 5 (West) to 8 (East) years; memory to past defoliation ranged from 8 (West) to 12 (East) years. The drier regional climate and faster FTC defoliation dynamics (compared to SBW) likely contribute to shorter ecosystem memory in the West. Drought and defoliation had the largest negative impact on large-diameter, host tree growth. Surprisingly, a positive interaction was observed between drought and defoliation for large-diameter, non-host trees likely due to reduced stand-level competition for water. Results highlight the

  12. Model-specification uncertainty in future forest pest outbreak.

    Science.gov (United States)

    Boulanger, Yan; Gray, David R; Cooke, Barry J; De Grandpré, Louis

    2016-04-01

    Climate change will modify forest pest outbreak characteristics, although there are disagreements regarding the specifics of these changes. A large part of this variability may be attributed to model specifications. As a case study, we developed a consensus model predicting spruce budworm (SBW, Choristoneura fumiferana [Clem.]) outbreak duration using two different predictor data sets and six different correlative methods. The model was used to project outbreak duration and the uncertainty associated with using different data sets and correlative methods (=model-specification uncertainty) for 2011-2040, 2041-2070 and 2071-2100, according to three forcing scenarios (RCP 2.6, RCP 4.5 and RCP 8.5). The consensus model showed very high explanatory power and low bias. The model projected a more important northward shift and decrease in outbreak duration under the RCP 8.5 scenario. However, variation in single-model projections increases with time, making future projections highly uncertain. Notably, the magnitude of the shifts in northward expansion, overall outbreak duration and the patterns of outbreaks duration at the southern edge were highly variable according to the predictor data set and correlative method used. We also demonstrated that variation in forcing scenarios contributed only slightly to the uncertainty of model projections compared with the two sources of model-specification uncertainty. Our approach helped to quantify model-specification uncertainty in future forest pest outbreak characteristics. It may contribute to sounder decision-making by acknowledging the limits of the projections and help to identify areas where model-specification uncertainty is high. As such, we further stress that this uncertainty should be strongly considered when making forest management plans, notably by adopting adaptive management strategies so as to reduce future risks. © 2015 Her Majesty the Queen in Right of Canada Global Change Biology © 2015 Published by John

  13. Blended Refuge and Insect Resistance Management for Insecticidal Corn

    Science.gov (United States)

    Crespo, Andre L B; Pan, Zaiqi; Crain, Philip R; Thompson, Stephen D; Pilcher, Clinton D; Sethi, Amit

    2018-01-01

    Abstract In this review, we evaluate the intentional mixing or blending of insecticidal seed with refuge seed for managing resistance by insects to insecticidal corn (Zea mays). We first describe the pest biology and farming practices that will contribute to weighing trade-offs between using block refuges and blended refuges. Case studies are presented to demonstrate how the trade-offs will differ in different systems. We compare biological aspects of several abstract models to guide the reader through the history of modeling, which has played a key role in the promotion or denigration of blending in various scientific debates about insect resistance management for insecticidal crops. We conclude that the use of blended refuge should be considered on a case-by-case basis after evaluation of insect biology, environment, and farmer behavior. For Diabrotica virgifera virgifera, Ostrinia nubilalis, and Helicoverpa zea in the United States, blended refuge provides similar, if not longer, delays in the evolution of resistance compared to separate block refuges. PMID:29220481

  14. 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.

  15. Intraguild competition and enhanced survival of western bean cutworm (Lepidoptera: Noctuidae) on transgenic Cry1Ab (MON810) Bacillus thuringiensis corn.

    Science.gov (United States)

    Dorhout, David L; Rice, Marlin E

    2010-02-01

    The effect of genetically modified corn (event MON810, YieldGard Corn Borer) expressing the Bacillus thuringiensis sp. kurstaki (Berliner) (Bt) endotoxin, Cry1Ab, on the survival of western bean cutworm, Striacosta albicosta (Smith), larvae was examined during intraguild competition studies with either European corn borer, Ostrinia nubilalis (Hübner), or corn earworm, Helicoverpa zea (Boddie), larvae. Competition scenarios were constructed by using either a laboratory or field competition arena containing one of five different diets and one of 13 different larval size-by-species scenarios. The survival of western bean cutworms competing with corn earworms in the laboratory arenas on either a meridic diet or isoline corn silk diet was significantly lower (P corn earworm on a Cry1Ab-MON810 corn silk diet was significant higher (P corn borers generally did not alter the outcomes observed in the western bean cutworm and corn earworm only two-way competitions. These data suggest that Cry1Ab-MON810 corn may confer a competitive advantage to western bean cutworm larvae during intraguild competition, particularly from corn earworms, and that western bean cutworms become equal competitors only when they are of equal or larger size and the diet is Cry1Ab-MON810 corn.

  16. Quantitative trait loci for maysin synthesis in maize (Zea mays L.) lines selected for high silk maysin content.

    Science.gov (United States)

    Meyer, J D F; Snook, M E; Houchins, K E; Rector, B G; Widstrom, N W; McMullen, M D

    2007-06-01

    Maysin is a naturally occurring C-glycosyl flavone found in maize (Zea mays L.) silk tissue that confers resistance to corn earworm (Helicoverpa zea, Boddie). Recently, two new maize populations were derived for high silk maysin. The two populations were named the exotic populations of maize (EPM) and the southern inbreds of maize (SIM). Quantitative trait locus (QTL) analysis was employed to determine which loci were responsible for elevated maysin levels in inbred lines derived from the EPM and SIM populations. The candidate genes consistent with QTL position included the p (pericarp color), c2 (colorless2), whp1 (white pollen1) and in1 (intensifier1) loci. The role of these loci in controlling high maysin levels in silks was tested by expression analysis and use of the loci as genetic markers onto the QTL populations. These studies support p, c2 and whp1, but not in1, as loci controlling maysin. Through this study, we determined that the p locus regulates whp1 transcription and that increased maysin in these inbred lines was primarily due to alleles at both structural and regulatory loci promoting increased flux through the flavone pathway by increasing chalcone synthase activity.

  17. Comparative studies of tripolyphosphate and glutaraldehyde cross-linked chitosan-botanical pesticide nanoparticles and their agricultural applications.

    Science.gov (United States)

    Gabriel Paulraj, Michael; Ignacimuthu, Savarimuthu; Gandhi, Munusamy Rajiv; Shajahan, Azeez; Ganesan, Pathalam; Packiam, Soosaimanickam Maria; Al-Dhabi, Naif Abdhullah

    2017-11-01

    A nanopesticide formulation was developed using chitosan and a botanical pesticide PONNEEM ® and its antifeedant, larvicidal and growth regulating activities were screened against Helicoverpa armigera, a major lepidopteran pest. Chitosan nanoparticles (CSNs) were prepared by using two different cross-linking agents namely glutaraldehyde (GLA) and tripolyphosphate (TPP). The effects of cross linking agents on CSNs and the biological properties against the insect pest were also studied. Cross linking of chitosan with either TPP or GLA was confirmed through Fourier Transform Infrared (FTIR) spectroscopy. Electron micrograph revealed that the size of CSNs varied from 32 to 90nm. The stability of nanoparticles lasted for 9days in CSNs-TPP-PONNEEM. In CSNs-GLA-PONNEEM, the stability of nanoparticles was higher. CSNs-TPP-PONNEEM treatment recorded 88.5% antifeedant activity and 90.2% larvicidal activity against H. armigera. Weights of H. armigera pupae in CSNs-TPP-PONNEEM treatment were significantly low. Chitosan-based nano-pesticide formulation holds great promise in H. armigera management. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Developing Cotton IPM by Conserving Parasitoids and Predators of The Main Pest

    Directory of Open Access Journals (Sweden)

    Nurindah Nurindah

    2015-09-01

    Full Text Available On early development of intensive cotton program, insect pests were considered as an important aspect in cotton cultivation, so that it needed to be scheduled sprays. The frequency of sprays was 7 times used 12L of chemical insecticides per hectare per season. Development of cotton IPM was emphasized on non-chemical control methods through optimally utilize natural enemies of the cotton main pests (Amrasca biguttulla (IshidaHelicoverpa armigera (Hübner. Conservation of parasitoids and predators by providing the environment that support their population development is an act of supporting the natural enemies as an effective biotic mortality factor of the insect pests. The conservation could be done by improving the plant matter and cultivation techniques that include the use of resistant variety to leafhopper, intercropping cotton with secondary food plants, mulch utilization, using action threshold that considered the presence of natural enemies, and application of botanical insecticides, if needed. Conservation of parasitoids and predators in cotton IPM could control the insect pests without any insecticide spray in obtaining the production of cotton seed. As such, the use of IPM method would increase farmers’ income.

  19. Arabidopsis thaliana resistance to insects, mediated by an earthworm-produced organic soil amendment.

    Science.gov (United States)

    Cardoza, Yasmin J

    2011-02-01

    Vermicompost is an organic soil amendment produced by earthworm digestion of organic waste. Studies show that plants grown in soil amended with vermicompost grow faster, are more productive and are less susceptible to a number of arthropod pests. In light of these studies, the present study was designed to determine the type of insect resistance (antixenosis or antibiosis) present in plants grown in vermicompost-amended potting soil. Additionally, the potential role of microarthropods, entomopathogenic organisms and non-pathogenic microbial flora found in vermicompost on insect resistance induction was investigated. Findings show that vermicompost from two different sources (Raleigh, North Carolina, and Portland, Oregon) were both effective in causing Arabidopsis plants to be resistant to the generalist herbivore Helicoverpa zea (Boddie). However, while the Raleigh (Ral) vermicompost plant resistance was expressed as both non-preference (antixenosis) and milder (lower weight and slower development) toxic effect (antibiosis) resistance, Oregon (OSC) vermicompost plant resistance was expressed as acute antibiosis, resulting in lower weights and higher mortality rates. Vermicompost causes plants to have non-preference (antixenosis) and toxic (antibiosis) effects on insects. This resistance affects insect development and survival on plants grown in vermicompost-amended soil. Microarthropods and entomopathogens do not appear to have a role in the resistance, but it is likely that resistance is due to interactions between the microbial communities in vermicompost with plant roots, as is evident from vermicompost sterilization assays conducted in this study. Copyright © 2010 Society of Chemical Industry.

  20. Reduced levels of membrane-bound alkaline phosphatase are common to lepidopteran strains resistant to Cry toxins from Bacillus thuringiensis.

    Directory of Open Access Journals (Sweden)

    Juan Luis Jurat-Fuentes

    Full Text Available Development of insect resistance is one of the main concerns with the use of transgenic crops expressing Cry toxins from the bacterium Bacillus thuringiensis. Identification of biomarkers would assist in the development of sensitive DNA-based methods to monitor evolution of resistance to Bt toxins in natural populations. We report on the proteomic and genomic detection of reduced levels of midgut membrane-bound alkaline phosphatase (mALP as a common feature in strains of Cry-resistant Heliothis virescens, Helicoverpa armigera and Spodoptera frugiperda when compared to susceptible larvae. Reduced levels of H. virescens mALP protein (HvmALP were detected by two dimensional differential in-gel electrophoresis (2D-DIGE analysis in Cry-resistant compared to susceptible larvae, further supported by alkaline phosphatase activity assays and Western blotting. Through quantitative real-time polymerase chain reaction (qRT-PCR we demonstrate that the reduction in HvmALP protein levels in resistant larvae are the result of reduced transcript amounts. Similar reductions in ALP activity and mALP transcript levels were also detected for a Cry1Ac-resistant strain of H. armigera and field-derived strains of S. frugiperda resistant to Cry1Fa. Considering the unique resistance and cross-resistance phenotypes of the insect strains used in this work, our data suggest that reduced mALP expression should be targeted for development of effective biomarkers for resistance to Cry toxins in lepidopteran pests.

  1. Replication of Syngrapha falcifera Multiple-Nuclear Polyhedrosis Virus-D in Different Insect Cells

    Science.gov (United States)

    Khalid Nessr Alhag, Sadeq; Xin, Peng Jian

    Six insect cell lines were tested for susceptibility to Syngrapha falcifera multiple nucleocapsid nucleopolyhedrovirus-D (SfaMNPV-D) infection by use of a typical endpoint assay procedure. Cell lines from Trichoplusia ni (Tn5B1-4), (L105-clone), Spodoptera litura (SL-ZSU-1), Spodoptera frugiperda (IPLB-SF-21), Pieris rapaeb (Pr-E-HNU9) and Helicoverpa zea (BCIRL-HZ-AM1) in 96-well tissue culture plates were infected with dilutions of extra cellular virus suspensions of (SfaMNPV-D). Each cell/virus combination was incubated at temperatures 27°C and wells were scored for positive infection at 2 to 4 day intervals. The resulting data were analyzed by Reed and Muench method, providing virus titers for each combination of virus, cell line. The results were categorized by accuracy and by rapidity of maximum titer. Virus titer of Tn5B-4 was higher than other cell lines TCID50 8.7x108, the lowest level detected in infected was in (Pr-E-HNU9) cells TCID50 2.4x108. No Virions or polyhedral inclusion bodies were detected in infected SL-ZSU-1 cells.

  2. 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.

  3. Mass rearing and augmentative biological control evaluation of Rhynocoris fuscipes (Hemiptera: Reduviidae) against multiple pests of cotton.

    Science.gov (United States)

    Tomson, Majesh; Sahayaraj, Kitherian; Kumar, Vivek; Avery, Pasco B; McKenzie, Cindy L; Osborne, Lance S

    2017-08-01

    Rhynocoris fuscipes (Fab.) (Hemiptera: Reduviidae) is a generalist predator of cotton pests and is commonly found inhabiting cotton-growing regions in southern India. With the goal of integrating this predator in standard management practices used against cotton pests on a commercial scale, (1) we developed a protocol for adult group rearing of this predator inside micro-environmental cages (MECs), and (2) we evaluated the biocontrol potential of mass-produced predators against cotton pests under potted and field conditions. Higher fecundity and adult longevity of R. fuscipes was recorded in the MECs than under natural growing conditions. The reduviid predator preferred stones and fallen leaves as hiding places in the MECs. The predator showed a higher biocontrol potential during the night hours against two pests, Phenacoccus solenopsis Tinsley and Dysdercus cingulatus (Fab.), than during the day under potted conditions. Under field conditions, R. fuscipes significantly reduced the population of Aphis gossypii Glover, P. solenopsis, D. cingulatus and Helicoverpa armigera (Hübner) by 28, 70, 29 and 50%, respectively. No negative impact of R. fuscipes was reported on other natural enemies present in the cotton agroecosystem. Significantly higher crop yield and cost benefit ratio were observed in R. fuscipes-released plots than in the control plots. The results suggest that R. fuscipes can be mass produced efficiently under controlled conditions in MECs, and used in an integrated management program for multiple cotton pests. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  4. Microbial control of phytophagous invertebrate pests in South Africa: Current status and future prospects.

    Science.gov (United States)

    Hatting, Justin L; Moore, Sean D; Malan, Antoinette P

    2018-02-07

    Invertebrate pests pose a significant threat to food security on the African continent. In response, South Africa has become one of the largest importers of chemical pesticides in sub-Saharan Africa, with several hundred active ingredients registered. To address the over-reliance on such chemicals, the South African Department of Agriculture, Forestry and Fisheries (DAFF) has eliminated or restricted several pesticides since the late 1970s. The recent launch of the South African National Bio-Economy Strategy and establishment of the South African Bioproducts Organisation (SABO), together with new guidelines for registration of biopesticides in 2015, also support this endeavour. Concurrently, entomopathogen-related research and bioproduct development has increased over the past decade. Currently, 31 products (seven manufactured locally) are registered under the Fertilizers, Farm Feeds, Agricultural Remedies and Stock Remedies Act 36 of 1947. Commercially important microbes include Beauveria bassiana (Cordycipitaceae), Metarhizium anisopliae (Clavicipitaceae), Cydia pomonella granulovirus, Cryptophlebia leucotreta granulovirus, Helicoverpa armigera nucleopolyhedrovirus (Baculoviridae) and Bacillus thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai (Bacillaceae). Both parasitic and entomopathogenic nematodes (EPNs) show potential for development as bioinsecticides with one commercial EPN product, based on Heterorhabditis bacteriophora (Heterorhabditidae), registered under the Act. Rapid scientific progression, supported by a favourable legislative environment, should facilitate further advances in microbial control of phytophagous invertebrate pests in South Africa. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Feeding behaviour of generalist pests on Brassica juncea: implication for manipulation of glucosinolate biosynthesis pathway for enhanced resistance.

    Science.gov (United States)

    Kumar, Pawan; Augustine, Rehna; Singh, Amarjeet Kumar; Bisht, Naveen C

    2017-10-01

    Differential accumulation of plant defence metabolites has been suggested to have important ecological consequence in the context of plant-insect interactions. Feeding of generalist pests on Brassica juncea showed a distinct pattern with selective exclusion of leaf margins which are high in glucosinolates. Molecular basis of this differential accumulation of glucosinolates could be explained based on differential expression profile of BjuMYB28 homologues, the major biosynthetic regulators of aliphatic glucosinolates, as evident from quantitative real-time PCR and promoter:GUS fusion studies in allotetraploid B. juncea. Constitutive overexpression of selected BjuMYB28 homologues enhanced accumulation of aliphatic glucosinolates in B. juncea. Performance of two generalist pests, Helicoverpa armigera and Spodoptera litura larvae, on transgenic B. juncea plants were poor compared to wild-type plants in a no-choice experiment. Correlation coefficient analysis suggested that weight gain of H. armigera larvae was negatively correlated with gluconapin (GNA) and glucobrassicanapin (GBN), whereas that of S. litura larvae was negatively correlated with GNA, GBN and sinigrin (SIN). Our study explains the significance and possible molecular basis of differential distribution of glucosinolates in B. juncea leaves and shows the potential of overexpressing BjuMYB28 for enhanced resistance of Brassica crops against the tested generalist pests. © 2017 John Wiley & Sons Ltd.

  6. Transgenic plants expressing the AaIT/GNA fusion protein show increased resistance and toxicity to both chewing and sucking pests.

    Science.gov (United States)

    Liu, Shu-Min; Li, Jie; Zhu, Jin-Qi; Wang, Xiao-Wei; Wang, Cheng-Shu; Liu, Shu-Sheng; Chen, Xue-Xin; Li, Sheng

    2016-04-01

    The adoption of pest-resistant transgenic plants to reduce yield losses and decrease pesticide use has been successful. To achieve the goal of controlling both chewing and sucking pests in a given transgenic plant, we generated transgenic tobacco, Arabidopsis, and rice plants expressing the fusion protein, AaIT/GNA, in which an insecticidal scorpion venom neurotoxin (Androctonus australis toxin, AaIT) is fused to snowdrop lectin (Galanthus nivalis agglutinin, GNA). Compared with transgenic tobacco and Arabidopsis plants expressing AaIT or GNA, transgenic plants expressing AaIT/GNA exhibited increased resistance and toxicity to one chewing pest, the cotton bollworm, Helicoverpa armigera. Transgenic tobacco and rice plants expressing AaIT/GNA showed increased resistance and toxicity to two sucking pests, the whitefly, Bemisia tabaci, and the rice brown planthopper, Nilaparvata lugens, respectively. Moreover, in the field, transgenic rice plants expressing AaIT/GNA exhibited a significant improvement in grain yield when infested with N. lugens. This study shows that expressing the AaIT/GNA fusion protein in transgenic plants can be a useful approach for controlling pests, particularly sucking pests which are not susceptible to the toxin in Bt crops. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  7. Ignoring the irrelevant: auditory tolerance of audible but innocuous sounds in the bat-detecting ears of moths

    Science.gov (United States)

    Fullard, James H.; Ratcliffe, John M.; Jacobs, David S.

    2008-03-01

    Noctuid moths listen for the echolocation calls of hunting bats and respond to these predator cues with evasive flight. The African bollworm moth, Helicoverpa armigera, feeds at flowers near intensely singing cicadas, Platypleura capensis, yet does not avoid them. We determined that the moth can hear the cicada by observing that both of its auditory receptors (A1 and A2 cells) respond to the cicada’s song. The firing response of the A1 cell rapidly adapts to the song and develops spike periods in less than a second that are in excess of those reported to elicit avoidance flight to bats in earlier studies. The possibility also exists that for at least part of the day, sensory input in the form of olfaction or vision overrides the moth’s auditory responses. While auditory tolerance appears to allow H. armigera to exploit a food resource in close proximity to acoustic interference, it may render their hearing defence ineffective and make them vulnerable to predation by bats during the evening when cicadas continue to sing. Our study describes the first field observation of an eared insect ignoring audible but innocuous sounds.

  8. Improved insecticidal toxicity by fusing Cry1Ac of Bacillus thuringiensis with Av3 of Anemonia viridis.

    Science.gov (United States)

    Yan, Fu; Cheng, Xing; Ding, Xuezhi; Yao, Ting; Chen, Hanna; Li, Wenping; Hu, Shengbiao; Yu, Ziquan; Sun, Yunjun; Zhang, Youming; Xia, Liqiu

    2014-05-01

    Av3, a neurotoxin of Anemonia viridis, is toxic to crustaceans and cockroaches but inactive in mammals. In the present study, Av3 was expressed in Escherichia coli Origami B (DE3) and purified by reversed-phase liquid chromatography. The purified Av3 was injected into the hemocoel of Helicoverpa armigera, rendering the worm paralyzed. Then, Av3 was expressed alone or fusion expressed with the Cry1Ac in acrystalliferous strain Cry(-)B of Bacillus thuringiensis. The shape of Cry1Ac was changed by fusion with Av3. The expressed fusion protein, Cry1AcAv3, formed irregular rhombus- or crescent-shaped crystalline inclusions, which is quite different from the shape of original Cry1Ac crystals. The toxicity of Cry1Ac was improved by fused expression. Compared with original Cry1Ac expressed in Cry(-)B, the oral toxicity of Cry1AcAv3 to H. armigera was elevated about 2.6-fold. No toxicity was detected when Av3 was expressed in Cry(-)B alone. The present study confirmed that marine toxins could be used in bio-control and implied that fused expression with other insecticidal proteins could be an efficient way for their application.

  9. Insect Larvae: A New Platform to Produce Commercial Recombinant Proteins.

    Science.gov (United States)

    Targovnik, Alexandra M; Arregui, Mariana B; Bracco, Lautaro F; Urtasun, Nicolas; Baieli, Maria F; Segura, Maria M; Simonella, Maria A; Fogar, Mariela; Wolman, Federico J; Cascone, Osvaldo; Miranda, Maria V

    2016-01-01

    In Biotechnology, the expression of recombinant proteins is a constantly growing field and different hosts are used for this purpose. Some valuable proteins cannot be produced using traditional systems. Insects from the order Lepidoptera infected with recombinant baculovirus have appeared as a good choice to express high levels of proteins, especially those with post-translational modifications. Lepidopteran insects, which are extensively distributed in the world, can be used as small protein factories, the new biofactories. Species like Bombyx mori (silkworm) have been analyzed in Asian countries to produce a great number of recombinant proteins for use in basic and applied science and industry. Many proteins expressed in this larva have been commercialized. Several recombinant proteins produced in silkworms have already been commercialized. On the other hand, species like Spodoptera frugiperda, Heliothis virescens, Rachiplusia nu, Helicoverpa zea and Trichoplusia ni are widely distributed in both the occidental world and Europe. The expression of recombinant proteins in larvae has the advantage of its low cost in comparison with insect cell cultures. A wide variety of recombinant proteins, including enzymes, hormones and vaccines, have been efficiently expressed with intact biological activity. The expression of pharmaceutically proteins, using insect larvae or cocoons, has become very attractive. This review describes the use of insect larvae as an alternative to produce commercial recombinant proteins.

  10. Identification and characterization of aldehyde oxidases (AOXs) in the cotton bollworm

    Science.gov (United States)

    Xu, Wei; Liao, Yalin

    2017-12-01

    Aldehyde oxidases (AOXs) are a family of metabolic enzymes that oxidize aldehydes into carboxylic acids; therefore, they play critical roles in detoxification and degradation of chemicals. By using transcriptomic and genomic approaches, we successfully identified six putative AOX genes (HarmAOX1-6) from cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). In silico expression profile, reverse transcription (RT)-PCR, and quantitative PCR (qPCR) analyses showed that HarmAOX1 is highly expressed in adult antennae, tarsi, and larval mouthparts, so they may play an important role in degrading plant-derived compounds. HarmAOX2 is highly and specifically expressed in adult antennae, suggesting a candidate pheromone-degrading enzyme (PDE) to inactivate the sex pheromone components (Z)-11-hexadecenal and (Z)-9-hexadecenal. RNA sequencing data further demonstrated that a number of host plants they feed on could significantly upregulate the expression levels of HarmAOX1 in larvae. This study improves our understanding of insect aldehyde oxidases and insect-plant interactions.

  11. Variasi Kebugaran Jenis/Strain Trichogramma pada Telur Plutella xylostella (L. (Lepidoptera: Plutellidae

    Directory of Open Access Journals (Sweden)

    Siti Herlinda

    2005-07-01

    Full Text Available Laboratory experiments were conducted to evaluate fitness traits of trichogrammatid species/strains reared on eggs of the diamondback moth, Plutella xylostella (L.. The experiments used eleven trichogrammatid species/strains collected from different host species and locations. They were Trichogrammatoidea cojuangcoi Nagaraja collected from parasitized P. xylostella eggs in Jarai, Muarasiban, Kerinjing, and Bogar, Trichogrammatoidea sp. A and B collected from parasitized Helicoverpa armigera (Hubner eggs in Bogor, Trichogrammatoidea armigera Nagaraja collected from parasitized H. armigera eggs in Bogor, Trichogramma chilonis Ishii, Trichogramma japanicum Ashmead, Trichogramma australicum Girault, and Trichogrammatoidea nana (Zehntner collected from parasitized Chilo sp. eggs in Cinta Manis, South Sumatera. When a female of Trichogramma was constantly exposed to 100 P. xylostella eggs per day throughout her lifetime, T. cojuangcoi from Jarai produced more parasitized host eggs (50.67% and progenies (50.67 adults/female compared to other species/strains. Sex ratio was predominantly female, the most female progenies were produced ( 38 adults/ female by T. cojuangcoi from Jarai. There were no significant differences in larval (0-3.27% and pupal (0-3.75% mortality of all species/strains. Survival emerging adults of T. japanicum (90.24% were significantly lower than those of other species/strains. These data showed that T. cojuangcoi from Jarai could be developed as biocontrol agents of P. xylostella.

  12. Conserved chemosensory proteins in the proboscis and eyes of Lepidoptera.

    Science.gov (United States)

    Zhu, Jiao; Iovinella, Immacolata; Dani, Francesca Romana; Liu, Yu-Ling; Huang, Ling-Qiao; Liu, Yang; Wang, Chen-Zhu; Pelosi, Paolo; Wang, Guirong

    2016-01-01

    Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) are endowed with several different functions besides being carriers for pheromones and odorants. Based on a previous report of a CSP acting as surfactant in the proboscis of the moth Helicoverpa armigera , we revealed the presence of orthologue proteins in two other moths Plutella xylostella and Chilo suppressalis , as well as two butterflies Papilio machaon and Pieris rapae , using immunodetection and proteomic analysis. The unusual conservation of these proteins across large phylogenetic distances indicated a common specific function for these CSPs. This fact prompted us to search for other functions of these proteins and discovered that CSPs are abundantly expressed in the eyes of H. armigera and possibly involved as carriers for carotenoids and visual pigments. This hypothesis is supported by ligand-binding experiments and docking simulations with retinol and β-carotene. This last orange pigment, occurring in many fruits and vegetables, is an antioxidant and the precursor of visual pigments. We propose that structurally related CSPs solubilise nutritionally important carotenoids in the proboscis, while they act as carriers of both β-carotene and its derived products 3-hydroxyretinol and 3-hydroxyretinal in the eye. The use of soluble olfactory proteins, such as CSPs, as carriers for visual pigments in insects, here reported for the first time, parallels the function of retinol-binding protein in vertebrates, a lipocalin structurally related to vertebrate odorant-binding proteins.

  13. MetaGaAP: A Novel Pipeline to Estimate Community Composition and Abundance from Non-Model Sequence Data

    Directory of Open Access Journals (Sweden)

    Christopher Noune

    2017-02-01

    Full Text Available Next generation sequencing and bioinformatic approaches are increasingly used to quantify microorganisms within populations by analysis of ‘meta-barcode’ data. This approach relies on comparison of amplicon sequences of ‘barcode’ regions from a population with public-domain databases of reference sequences. However, for many organisms relevant ‘barcode’ regions may not have been identified and large databases of reference sequences may not be available. A workflow and software pipeline, ‘MetaGaAP,’ was developed to identify and quantify genotypes through four steps: shotgun sequencing and identification of polymorphisms in a metapopulation to identify custom ‘barcode’ regions of less than 30 polymorphisms within the span of a single ‘read’, amplification and sequencing of the ‘barcode’, generation of a custom database of polymorphisms, and quantitation of the relative abundance of genotypes. The pipeline and workflow were validated in a ‘wild type’ Alphabaculovirus isolate, Helicoverpa armigera single nucleopolyhedrovirus (HaSNPV-AC53 and a tissue-culture derived strain (HaSNPV-AC53-T2. The approach was validated by comparison of polymorphisms in amplicons and shotgun data, and by comparison of predicted dominant and co-dominant genotypes with Sanger sequences. The computational power required to generate and search the database effectively limits the number of polymorphisms that can be included in a barcode to 30 or less. The approach can be used in quantitative analysis of the ecology and pathology of non-model organisms.

  14. Baseline sensitivity of lepidopteran corn pests in India to Cry1Ab insecticidal protein of Bacillus thuringiensis.

    Science.gov (United States)

    Jalali, Sushil K; Lalitha, Yadavalli; Kamath, Subray P; Mohan, Komarlingam S; Head, Graham P

    2010-08-01

    Genetically engineered corn (Bt corn) expressing Bacillus thuringiensis Berliner insecticidal protein Cry1Ab is a biotechnological option being considered for management of lepidopteran corn pests in India. As a resistance management practice it was essential to determine the sensitivity of multiple populations of the stalk borer Chilo partellus (Swinhoe), pink borer Sesamia inferens (Walker) and the cob borer Helicoverpa armigera (Hübner) to Cry1Ab protein through bioassays. The insect populations were collected during growing seasons of Rabi 2005 (October 2005 to February 2006) and Kharif 2006 (May to September 2006). Multiple populations of the three lepidopteran corn pests were found to be susceptible to Cry1Ab. Median lethal concentrations (LC(50)) ranged between 0.008 and 0.068 microg Cry1Ab mL(-1) diet for 18 populations of C. partellus (across two seasons), between 0.12 and 1.99 microg mL(-1) for seven populations of H. armigera and between 0.46 and 0.56 microg mL(-1) for two populations of S. inferens. Dose-response concentrations for lethality and growth inhibition have been determined to mark baseline sensitivity of multiple populations of key lepidopteran corn pests in India to Cry1Ab protein. These benchmark values will be referenced while monitoring resistance to Cry1Ab should Bt corn hybrids expressing Cry1Ab be approved for commercial cultivation in India. Copyright (c) 2010 Society of Chemical Industry.

  15. Weakening density dependence from climate change and agricultural intensification triggers pest outbreaks: a 37-year observation of cotton bollworms.

    Science.gov (United States)

    Ouyang, Fang; Hui, Cang; Ge, Saiying; Men, Xin-Yuan; Zhao, Zi-Hua; Shi, Pei-Jian; Zhang, Yong-Sheng; Li, Bai-Lian

    2014-09-01

    Understanding drivers of population fluctuation, especially for agricultural pests, is central to the provision of agro-ecosystem services. Here, we examine the role of endogenous density dependence and exogenous factors of climate and human activity in regulating the 37-year population dynamics of an important agricultural insect pest, the cotton bollworm (Helicoverpa armigera), in North China from 1975 to 2011. Quantitative time-series analysis provided strong evidence explaining long-term population dynamics of the cotton bollworm and its driving factors. Rising temperature and declining rainfall exacerbated the effect of agricultural intensification on continuously weakening the negative density dependence in regulating the population dynamics of cotton bollworms. Consequently, ongoing climate change and agricultural intensification unleashed the tightly regulated pest population and triggered the regional outbreak of H. armigera in 1992. Although the negative density dependence can effectively regulate the population change rate to fluctuate around zero at stable equilibrium levels before and after outbreak in the 1992, the population equilibrium jumped to a higher density level with apparently larger amplitudes after the outbreak. The results highlight the possibility for exogenous factors to induce pest outbreaks and alter the population regulating mechanism of negative density dependence and, thus, the stable equilibrium of the pest population, often to a higher level, posing considerable risks to the provision of agro-ecosystem services and regional food security. Efficient and timely measures of pest management in the era of Anthropocene should target the strengthening and revival of weakening density dependence caused by climate change and human activities.

  16. Enhanced Methanol Production in Plants Provides Broad Spectrum Insect Resistance

    Science.gov (United States)

    Dixit, Sameer; Upadhyay, Santosh Kumar; Singh, Harpal; Sidhu, Om Prakash; Verma, Praveen Chandra; K, Chandrashekar

    2013-01-01

    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. PMID:24223989

  17. Assessment of pest and pesticide trends in vegetable crops in united arab emirates and sultanate of oman

    International Nuclear Information System (INIS)

    Waakeh, W.; Aldahmani, J.H.; Deadman, M.L.; Saadi, A.A.

    2007-01-01

    A preliminary survey on pesticide uses in 40 vegetable-growing farms representing different agricultural areas in Oman and the UAE, twenty farms from each country, revealed that all the vegetable farms used pesticides for crop protection. Among the major insect-pests, white flies (Bemisia tabaci), leafminers (Liriomyza trifolii), melon fruit flies (Bactrocera ciliatus), aphids (Aphis spp.) and tobacco leafworm (Spodoptera litteralis) were recorded in Omani farms. In the UAE, white flies, leafminers, cutworms (Agrotis ypsilan), tomato fruitworms (Helicoverpa armigera) and eggplant fruitworms (Leucinodes orbonalis) were the 5 top insect-pests. Among the plant diseases, powdery mildew (Erysiphe spp.), blight (Alternaria spp.), damping off (Pythium spp.), leafspot (Alternaria spp.) and mosaic (CMV) Were major cause of vegetable diseases in Omani farms; whereas, damping off (Pythium aphanidermatum), downy mildew (Pseudoperonspora cubensis), early blight (Alternaria solani), septoria leaf spot (Septoria lycopersici) and anthracnose rip rot (colletotrichum spp.) were the most predominant diseases encountered in most UAE farms. Among the most commonly used pesticides, 29 insecticides, 16 fungicides and 3 herbicides were used by the vegetable farmers. Around 55% of Omani farms used routine application of pesticides, irrespective of the pest presence. Whereas, in the UAE, most farmers started to spray pesticides at 6-20% pest (insect, disease and weeds) infection. Over 65 of the farms, in both the countries, received chemical pest management information from the sales representatives. (author)

  18. How dietary plant nectar affects the survival, growth, and fecundity of a cursorial spider Cheiracanthium inclusum (Araneae: Miturgidae).

    Science.gov (United States)

    Taylor, R M; Pfannenstiel, R S

    2009-10-01

    We measured the effects of plant nectar consumption on Cheiracanthium inclusum (Hentz) (Miturgidae), an agriculturally important spider. Newly emerged spiderlings were reared on the eggs of Helicoverpa zea (Boddie) at four prey densities, 1, 5, 25, or 125 eggs, three times a week, with or without nectar. Nectar came from the extrafloral nectaries of Indian almond, Terminalia cattapa L. (Combretaceae). The addition of nectar to prey (1) allowed spiderlings on the 1-egg diet to survive longer and molt many more times; (2) allowed virtually all of the spiderlings on the 5-egg diet to become small adults and 50% to mate and reproduce versus those without nectar, none of which matured to adulthood; and (3) increased fecundity of females on 5-egg and 25-egg diets to the level of females fed five times the amount of prey. These results show that spiders that feed on nectar increase their fitness with increased survival, growth, and fecundity, particularly when density of prey is inadequate or marginal.

  19. Quantitative trait loci and metabolic pathways

    Science.gov (United States)

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

    1998-01-01

    The interpretation of quantitative trait locus (QTL) studies is limited by the lack of information on metabolic pathways leading to most economic traits. Inferences about the roles of the underlying genes with a pathway or the nature of their interaction with other loci are generally not possible. An exception is resistance to the corn earworm Helicoverpa zea (Boddie) in maize (Zea mays L.) because of maysin, a C-glycosyl flavone synthesized in silks via a branch of the well characterized flavonoid pathway. Our results using flavone synthesis as a model QTL system indicate: (i) the importance of regulatory loci as QTLs, (ii) the importance of interconnecting biochemical pathways on product levels, (iii) evidence for “channeling” of intermediates, allowing independent synthesis of related compounds, (iv) the utility of QTL analysis in clarifying the role of specific genes in a biochemical pathway, and (v) identification of a previously unknown locus on chromosome 9S affecting flavone level. A greater understanding of the genetic basis of maysin synthesis and associated corn earworm resistance should lead to improved breeding strategies. More broadly, the insights gained in relating a defined genetic and biochemical pathway affecting a quantitative trait should enhance interpretation of the biological basis of variation for other quantitative traits. PMID:9482823

  20. Incidência natural e biologia de Trichogramma atopovirilia Oatman & Platner, 1983 (Hymenoptera, Trichogrammatidae em ovos de Anticarsia gemmatalis Hübner, 1818 (Lepidoptera, Noctuidae Natural incidence and biology of Trichogramma atopovirilia Oatman & Platner, 1983 (Hymenoptera, Trichogrammatidae in eggs of Anticarsia gemmatalis Hübner, 1818 (Lepidoptera, Noctuidae

    Directory of Open Access Journals (Sweden)

    Carolina L. Cañete

    2003-01-01

    Full Text Available Trichogramma atopovirilia Oatman & Platner is an egg parasitoid of the corn earworm Helicoverpa zea (Boddie (Lepidoptera, Noctuidae, and has recently been collected from eggs of Anticarsia gemmatalis Hübner on soybeans. In order to evaluate the suitability of A. gemmatalis eggs as hosts of T. atopovirilia, field surveys were conducted in 1999 and 2000 on corn and soybeans, and a colony of the parasitoid was established in laboratory. At 25 ºC, development from oviposition to emergence lasted nine days and a sex-ratio of 0.58 (females:males was obtained. Females lived significantly longer (11.4 days when kept in ovipositional activity, than in the absence of host eggs (6.6 days. Total fecundity averaged 104.5 parasitized eggs, resulting in the emergence of 138.3 descendents. Mean daily fecundity was highest (30 eggs/female on the first day. Oviposition continued until one day before the death of the females, however 70% of the eggs were laid during the first four days after emergence. A female-biased progeny was produced during the first three days of oviposition, whereas further ovipositions were male-biased. Females lived significantly longer when exposed to host eggs in comparison to females deprived of eggs. The results show that eggs of A. gemmatalis are suitable for the development of T. atopovirilia, and this parasitoid should be considered in future programs of biological control of the velvetbean caterpillar.

  1. Coincidence of pheromone and plant odor leads to sensory plasticity in the heliothine olfactory system.

    Directory of Open Access Journals (Sweden)

    Elena Ian

    Full Text Available Male moths possess a highly specialized olfactory system comprised of two segregated sub-arrangements dedicated to processing information about plant odors and pheromones, respectively. Communication between these two sub-systems has been described at the peripheral level, but relatively little is known about putative interactions at subsequent synaptic relays. The male moth faces the challenge of seeking out the conspecific female in a highly dynamic odor world. The female-produced pheromone blend, which is a limited resource serving as guidance for the male, will reach his antennae in intermittent pockets of odor filaments mixed with volatiles from various plants. In the present study we performed calcium imaging for measuring odor-evoked responses in the uni-glomerular antennal-lobe projection neurons (analog to mitral cells in the vertebrate olfactory bulb of Helicoverpa armigera. In order to investigate putative interactions between the two sub-systems tuned to plant volatiles and pheromones, respectively, we performed repeated stimulations with a selection of biologically relevant odors. We found that paired stimulation with a plant odor and the pheromone led to suppressed responses in both sub-systems as compared to those evoked during initial stimulation including application of each odor stimulus alone. The fact that the suppression persisted also after pairing, indicates the existence of a Hebbian-like plasticity in the primary olfactory center established by temporal pairing of the two odor stimulation categories.

  2. Beauveria medogensis sp. nov., a new fungus of the entomopathogenic genus from China.

    Science.gov (United States)

    Imoulan, Abdessamad; Wu, Hai-Jun; Lu, Wei-Lai; Li, Yi; Li, Bin-Bin; Yang, Rei-Heng; Wang, Wen-Jing; Wang, Xiao-Liang; Kirk, Paul M; Yao, Yi-Jian

    2016-09-01

    Beauveria is among the most ubiquitous genera of entomopathogenic fungi throughout the world. A previously unknown species of the genus was recently discovered from a soil sample collected from Tibetan Plateau, China and is here described as new to science, B. medogensis sp. nov. The new species is distinguished from its closest relatives based on both morphological characterization and molecular phylogenetic analyses. Beauveria medogensis is characterized by globose to subglobose conidia, morphologically similar to some other species of in the genus, but was conclusively separated from those species in the phylogenetic analyses including sequences of four nuclear genes (RPB1, RPB2, TEF1 and Bloc). The new species was clustered in the analyses in a single terminal lineage which was grouped with B. australis sequences together as a sister clade to the B. brongniartii terminal clade. Although molecularly closely related, the new species is distinct morphologically from its closest sisters, B. australis and B. brongniartii, in producing globose to subglobose conidia rather than subglobose, broadly ellipsoid to ellipsoid conidia or ellipsoidal to cylindrical conidia. As isolated from a soil sample, the entomopathogenicity of the new species has been confirmed using Helicoverpa armigera and Tenebrio molitor larvae. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Developing Bisexual Attract-and-Kill for Polyphagous Insects: Ecological Rationale versus Pragmatics.

    Science.gov (United States)

    Gregg, Peter C; Del Socorro, Alice P; Hawes, Anthony J; Binns, Matthew R

    2016-07-01

    We discuss the principles of bisexual attract-and-kill, in which females as well as males are targeted with an attractant, such as a blend of plant volatiles, combined with a toxicant. While the advantages of this strategy have been apparent for over a century, there are few products available to farmers for inclusion in integrated pest management schemes. We describe the development, registration, and commercialization of one such product, Magnet(®), which was targeted against Helicoverpa armigera and H. punctigera in Australian cotton. We advocate an empirical rather than theoretical approach to selecting and blending plant volatiles for such products, and emphasise the importance of field studies on ecologically realistic scales of time and space. The properties required of insecticide partners also are discussed. We describe the studies that were necessary to provide data for registration of the Magnet(®) product. These included evidence of efficacy, including local and area-wide impacts on the target pest, non-target impacts, and safety for consumers and applicators. In the decade required for commercial development, the target market for Magnet(®) has been greatly reduced by the widespread adoption of transgenic insect-resistant cotton in Australia. We discuss potential applications in resistance management for transgenic cotton, and for other pests in cotton and other crops.

  4. Transgenic Cotton Plants Expressing Double-stranded RNAs Target HMG-CoA Reductase (HMGR) Gene Inhibits the Growth, Development and Survival of Cotton Bollworms.

    Science.gov (United States)

    Tian, Geng; Cheng, Linlin; Qi, Xuewei; Ge, Zonghe; Niu, Changying; Zhang, Xianlong; Jin, Shuangxia

    2015-01-01

    RNA interference (RNAi) has been developed as a powerful technique in the research of functional genomics as well as plant pest control. In this report, double-stranded RNAs (dsRNA) targeting 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) gene, which catalyze a rate-limiting enzymatic reaction in the mevalonate pathway of juvenile hormone (JH) synthesis in cotton bollworm, was expressed in cotton plants via Agrobacterium tumefaciens-mediated transformation. PCR and Sothern analysis revealed the integration of HMGR gene into cotton genome. RT-PCR and qRT-PCR confirmed the high transcription level of dsHMGR in transgenic cotton lines. The HMGR expression both in transcription and translation level was significantly downregulated in cotton bollworms (helicoverpa armigera) larvae after feeding on the leaves of HMGR transgenic plants. The transcription level of HMGR gene in larvae reared on transgenic cotton leaves was as much as 80.68% lower than that of wild type. In addition, the relative expression level of vitellogenin (Vg, crucial source of nourishment for offspring embryo development) gene was also reduced by 76.86% when the insect larvae were fed with transgenic leaves. The result of insect bioassays showed that the transgenic plant harboring dsHMGR not only inhibited net weight gain but also delayed the growth of cotton bollworm larvae. Taken together, transgenic cotton plant expressing dsRNAs successfully downregulated HMGR gene and impaired the development and survival of target insect, which provided more option for plant pest control.

  5. 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.

  6. Juvenile hormone prevents 20-hydroxyecdysone-induced metamorphosis by regulating the phosphorylation of a newly identified broad protein.

    Science.gov (United States)

    Cai, Mei-Juan; Liu, Wen; Pei, Xu-Yang; Li, Xiang-Ru; He, Hong-Juan; Wang, Jin-Xing; Zhao, Xiao-Fan

    2014-09-19

    The steroid hormone 20-hydroxyecdysone (20E) initiates insect molting and metamorphosis. By contrast, juvenile hormone (JH) prevents metamorphosis. However, the mechanism by which JH inhibits metamorphosis remains unclear. In this study, we propose that JH induces the phosphorylation of Broad isoform Z7 (BrZ7), a newly identified protein, to inhibit 20E-mediated metamorphosis in the lepidopteran insect Helicoverpa armigera. The knockdown of BrZ7 in larvae inhibited metamorphosis by repressing the expression of the 20E response gene. BrZ7 was weakly expressed and phosphorylated during larval growth but highly expressed and non-phosphorylated during metamorphosis. JH regulated the rapid phosphorylation of BrZ7 via a G-protein-coupled receptor-, phospholipase C-, and protein kinase C-triggered pathway. The phosphorylated BrZ7 bound to the 5'-regulatory region of calponin to regulate its expression in the JH pathway. Exogenous JH induced BrZ7 phosphorylation to prevent metamorphosis by suppressing 20E-related gene transcription. JH promoted non-phosphorylated calponin interacting with ultraspiracle protein to activate the JH pathway and antagonize the 20E pathway. This study reveals one of the possible mechanisms by which JH counteracts 20E-regulated metamorphosis by inducing the phosphorylation of BrZ7. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Juvenile Hormone Prevents 20-Hydroxyecdysone-induced Metamorphosis by Regulating the Phosphorylation of a Newly Identified Broad Protein*

    Science.gov (United States)

    Cai, Mei-Juan; Liu, Wen; Pei, Xu-Yang; Li, Xiang-Ru; He, Hong-Juan; Wang, Jin-Xing; Zhao, Xiao-Fan

    2014-01-01

    The steroid hormone 20-hydroxyecdysone (20E) initiates insect molting and metamorphosis. By contrast, juvenile hormone (JH) prevents metamorphosis. However, the mechanism by which JH inhibits metamorphosis remains unclear. In this study, we propose that JH induces the phosphorylation of Broad isoform Z7 (BrZ7), a newly identified protein, to inhibit 20E-mediated metamorphosis in the lepidopteran insect Helicoverpa armigera. The knockdown of BrZ7 in larvae inhibited metamorphosis by repressing the expression of the 20E response gene. BrZ7 was weakly expressed and phosphorylated during larval growth but highly expressed and non-phosphorylated during metamorphosis. JH regulated the rapid phosphorylation of BrZ7 via a G-protein-coupled receptor-, phospholipase C-, and protein kinase C-triggered pathway. The phosphorylated BrZ7 bound to the 5′-regulatory region of calponin to regulate its expression in the JH pathway. Exogenous JH induced BrZ7 phosphorylation to prevent metamorphosis by suppressing 20E-related gene transcription. JH promoted non-phosphorylated calponin interacting with ultraspiracle protein to activate the JH pathway and antagonize the 20E pathway. This study reveals one of the possible mechanisms by which JH counteracts 20E-regulated metamorphosis by inducing the phosphorylation of BrZ7. PMID:25096576

  8. The evolution and expression of the moth visual opsin family.

    Directory of Open Access Journals (Sweden)

    Pengjun Xu

    Full Text Available Because visual genes likely evolved in response to their ambient photic environment, the dichotomy between closely related nocturnal moths and diurnal butterflies forms an ideal basis for investigating their evolution. To investigate whether the visual genes of moths are associated with nocturnal dim-light environments or not, we cloned long-wavelength (R, blue (B and ultraviolet (UV opsin genes from 12 species of wild-captured moths and examined their evolutionary functions. Strong purifying selection appeared to constrain the functions of the genes. Dark-treatment altered the levels of mRNA expression in Helicoverpa armigera such that R and UV opsins were up-regulated after dark-treatment, the latter faster than the former. In contrast, B opsins were not significantly up-regulated. Diel changes of opsin mRNA levels in both wild-captured and lab-reared individuals showed no significant fluctuation within the same group. However, the former group had significantly elevated levels of expression compared with the latter. Consequently, environmental conditions appeared to affect the patterns of expression. These findings and the proportional expression of opsins suggested that moths potentially possessed color vision and the visual system played a more important role in the ecology of moths than previously appreciated. This aspect did not differ much from that of diurnal butterflies.

  9. The halo effect: suppression of pink bollworm on non-Bt cotton by Bt cotton in China.

    Directory of Open Access Journals (Sweden)

    Peng Wan

    Full Text Available In some previously reported cases, transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt have suppressed insect pests not only in fields planted with such crops, but also regionally on host plants that do not produce Bt toxins. Here we used 16 years of field data to determine if Bt cotton caused this "halo effect" against pink bollworm (Pectinophora gossypiella in six provinces of the Yangtze River Valley of China. In this region, the percentage of cotton hectares planted with Bt cotton increased from 9% in 2000 to 94% in 2009 and 2010. We found that Bt cotton significantly decreased the population density of pink bollworm on non-Bt cotton, with net decreases of 91% for eggs and 95% for larvae on non-Bt cotton after 11 years of Bt cotton use. Insecticide sprays targeting pink bollworm and cotton bollworm (Helicoverpa armigera decreased by 69%. Previously reported evidence of the early stages of evolution of pink bollworm resistance to Bt cotton in China has raised concerns that if unchecked, such resistance could eventually diminish or eliminate the benefits of Bt cotton. The results reported here suggest that it might be possible to find a percentage of Bt cotton lower than the current level that causes sufficient regional pest suppression and reduces the risk of resistance.

  10. Ensacamento de frutos do tomateiro visando ao controle de pragas e à redução de defensivos Paper bags for pest control and pesticide use reduction on tomato fruits

    Directory of Open Access Journals (Sweden)

    Alexandre Luis Jordão

    2002-06-01

    Full Text Available O ensacamento de frutos durante o seu desenvolvimento na planta, além do objetivo de controlar pragas pode reduzir resíduos de defensivos e manejar aspectos qualitativos. Com o objetivo de controle das pragas Neoleucinodes elegantalis, Helicoverpa zea e Tuta absoluta e redução de resíduos de inseticidas, pencas de tomates, foram ensacadas com papel-manteiga. Além do efeito do ensacamento, foram testados dois repelentes de insetos. Foram realizados cinco tratamentos. A eficiência do ensacamento e dos repelentes foi verificada por meio do número médio de lagartas encontradas por tratamento. A quantidade de resíduo de metamidofós encontrada nos frutos ensacados e nos frutos expostos diretamente à pulverização foi comparada ao limite máximo permitido. Verificou-se, também, a qualidade dos frutos produzidos pelo método do ensacamento através de análises físico-químicas dos tomates. Os custos do método do ensacamento foram comparados aos do método químico. O ensacamento, associado ou não aos repelentes, reduz o ataque das lagartas N. elegantalis e H. zea aos frutos. Para o controle de T. absoluta é necessária a integração com controle químico nas épocas de maior infestação. Os frutos não ensacados possuíam quantidade de metamidofós seis vezes superiores ao máximo tolerado e os frutos ensacados quantidade três vezes inferiores a este limite. O ensacamento das pencas de tomates não modificou os parâmetros físico-químicos dos frutos produzidos. O método do ensacamento requer maior investimento econômico, porém esse investimento atinge um mercado diferencial, com preços mais elevados.The development of fruits in paper bags aims at the control of pests, reduction of pesticide residues and the management of qualitative aspects. This work evaluates the efficacy of paper bags in combination with deodorant tablets and garlic clove on the control of the pest agents Neoleucinodes elegantalis, Helicoverpa zea and Tuta

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

    Directory of Open Access Journals (Sweden)

    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

  12. Laboratory Assessment on Virulence of Nomuraea rileyi against Noctuid Larvae%莱氏野村菌对夜蛾科害虫防治潜力的室内评测

    Institute of Scientific and Technical Information of China (English)

    周立峰; 于士军; 刘元兵; 王滨

    2012-01-01

    本文用喷雾法测定了5株莱氏野村菌Nomuraea rileyi对棉铃虫Helicoverpa armigera、甜菜夜蛾Spodoptera exigua和斜纹夜蛾Spodoptera litura 3种夜蛾科害虫的致病力。配制孢子悬浮液对3种夜蛾科害虫进行雾化接种,孢子附着量为188.9~4048.3孢子.mm 2。接种后幼虫置于(24±1)℃和12L∶12D条件下人工饲料饲养,每天观察直至化蛹。时间-剂量-死亡率模型分析显示:5株莱氏野村菌菌株接种量为188.9~4048.3孢子.mm 2时,斜纹夜蛾第10 d的侵染率为60%~95%;菌株Nr15对斜纹夜蛾显示出极高的毒力水平(LC50=266.7孢子.mm 2,4048.3孢子.mm 2浓度下的LT50=5.81 d),第10 d的侵染率达95%。供试菌株对棉铃虫和甜菜夜蛾的致病力相对较弱,侵染率均不足50%。研究表明,莱氏野村菌菌株对夜蛾科害虫体现出明显的寄主专化性,且有明显的量效关系。%In the current study,a laboratory bioassay was developed to measure the pathogenicities of five Nomuraea rileyi strains against Helicoverpa armigera,Spodoptera exigua and Spodoptera litura of noctuid larvae.The larvae were inoculated with conidia suspensions of N.rileyi at concentrations of 188.9 4048.3 conidia.mm 2 by a Potter Spray Tower,with 0.05% Tween-80 as control.After inoculation,the larvae were individually fed on artificial diet in plastic boxes at(24±1) ℃ and 12L:12D until pupated.Time-dose-mortality model was used to analyze the effect and indicated that the 5 fungal strains could kill 60% 95% of S.litura larvae at concentrations of 188.9 4048.3 conidia.mm 2within 10 d after conidia inoculation.Strain Nr15 demonstrated high virulence to S.litura larvae with a LC50value of 266.7 conidia.mm 2and a LT50value of 5.81 d at the concentration of 4048.3 conidia.mm 2,whereas mortalities of H.armigera and S.exigua didn’t reached 50%.The difference of mortality and fungal infection indicated that there is a host-specificity of N.rileyi strains to noctuid

  13. Intraear Compensation of Field Corn, Zea mays, from Simulated and Naturally Occurring Injury by Ear-Feeding Larvae.

    Science.gov (United States)

    Steckel, S; Stewart, S D

    2015-06-01

    Ear-feeding larvae, such as corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), can be important insect pests of field corn, Zea mays L., by feeding on kernels. Recently introduced, stacked Bacillus thuringiensis (Bt) traits provide improved protection from ear-feeding larvae. Thus, our objective was to evaluate how injury to kernels in the ear tip might affect yield when this injury was inflicted at the blister and milk stages. In 2010, simulated corn earworm injury reduced total kernel weight (i.e., yield) at both the blister and milk stage. In 2011, injury to ear tips at the milk stage affected total kernel weight. No differences in total kernel weight were found in 2013, regardless of when or how much injury was inflicted. Our data suggested that kernels within the same ear could compensate for injury to ear tips by increasing in size, but this increase was not always statistically significant or sufficient to overcome high levels of kernel injury. For naturally occurring injury observed on multiple corn hybrids during 2011 and 2012, our analyses showed either no or a minimal relationship between number of kernels injured by ear-feeding larvae and the total number of kernels per ear, total kernel weight, or the size of individual kernels. The results indicate that intraear compensation for kernel injury to ear tips can occur under at least some conditions. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Impact of Corn Earworm (Lepidoptera: Noctuidae) on Field Corn (Poales: Poaceae) Yield and Grain Quality.

    Science.gov (United States)

    Bibb, Jenny L; Cook, Donald; Catchot, Angus; Musser, Fred; Stewart, Scott D; Leonard, Billy Rogers; Buntin, G David; Kerns, David; Allen, Tom W; Gore, Jeffrey

    2018-05-28

    Corn earworm, Helicoverpa zea (Boddie), commonly infests field corn, Zea mays (L.). The combination of corn plant biology, corn earworm behavior in corn ecosystems, and field corn value renders corn earworm management with foliar insecticides noneconomical. Corn technologies containing Bacillus thuringiensis (Bt) Berliner (Bacillales: Bacillaceae) were introduced that exhibit substantial efficacy against corn earworm and may reduce mycotoxin contamination in grain. The first generation Bt traits in field corn demonstrated limited activity on corn earworm feeding on grain. The pyramided corn technologies have greater cumulative protein concentrations and higher expression throughout the plant, so these corn traits should provide effective management of this pest. Additionally, reduced kernel injury may affect physical grain quality. Experiments were conducted during 2011-2012 to investigate corn earworm impact on field corn yield and grain quality. Treatments included field corn hybrids expressing the Herculex, YieldGard, and Genuity VT Triple Pro technologies. Supplemental insecticide treatments were applied every 1-2 d from silk emergence until silk senescence to create a range of injured kernels for each technology. No significant relationship between the number of corn earworm damaged kernels and yield was observed for any technology/hybrid. In these studies, corn earworm larvae did not cause enough damage to impact yield. Additionally, no consistent relationship between corn earworm damage and aflatoxin contamination was observed. Based on these data, the economic value of pyramided Bt corn traits to corn producers, in the southern United States, appears to be from management of other lepidopteran insect pests including European and southwestern corn borer.

  15. Effects of Carriers, Emulsifiers, and Biopesticides for Direct Silk Treatments on Caterpillar Feeding Damage and Ear Development in Sweet Corn.

    Science.gov (United States)

    Westgate, P J; Schultz, B B; Hazzard, R V

    2017-04-01

    In the northeastern United States, control of Lepidopteran pests of sweet corn, particularly corn earworm [Helicoverpa zea (Boddie)], is difficult using organic methods. The direct application of corn oil and Bacillus thuringiensis (Bt) to corn silk has been shown to reduce ear damage from corn earworm in past studies; these studies sought to optimize this method by evaluating additional carrier and biopesticide mixtures that comply with the United States Federal Insecticide, Fungicide, and Rodenticide Act and National Organic Standards. Carriers, which are liquids used to dissolve the biopesticide and deliver it into the tip of the ear, may have phytotoxic or insecticidal properties. Experiments conducted from 2001 to 2005 evaluated caterpillar damage and ear development effects from carriers (vegetable and paraffinic oils and carrageenan), biopesticides (Bt, spinsosad, and neem), and three emulsifiers in various combinations when applied directly to the tips of the ears 5-7 d after silk initiation. There were no effects of emulsifiers on ear quality, except for slight reduction in caterpillar damage in one of the two years. There were no differences among corn, soy, canola, and safflower oils in corn earworm control or tip development. The carrageenan carrier had the least effect upon ear development as measured by the length of nonpollinated kernels at the tip, compared to corn oil or paraffinic oil (JMS Stylet Oil), which caused the greatest tip damage as well as an oily discoloration. The carrier-pesticide combinations with the best ear quality overall were spinosad in carrageenan or corn oil, and Bt in carrageenan. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Identification of multiple ear-colonizing insect and disease resistance in CIMMYT maize inbred lines with varying levels of silk maysin.

    Science.gov (United States)

    Ni, Xinzhi; Krakowsky, Matthew D; Buntin, G David; Rector, Brian G; Guo, Baozhu; Snook, Maurice E

    2008-08-01

    Ninety four corn inbred lines selected from International Center for the Improvement of Maize and Wheat (CIMMYT) in Mexico were evaluated for levels of silk maysin in 2001 and 2002. Damage by major ear-feeding insects [i.e., corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae); maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae); brown stink bug, Euschistus servus (Say); southern green stink bugs, Nezara viridula (L.) (Heteroptera: Pentatomidae)], and common smut [Ustilago maydis DC (Corda)] infection on these inbred lines were evaluated in 2005 and 2006 under subtropical conditions at Tifton, GA. Ten inbred lines possessing good agronomic traits were also resistant to the corn earworm. The correlation between ear-feeding insect damage or smut infection and three phenotypic traits (silk maysin level, husk extension, and husk tightness of corn ears) was also examined. Corn earworm and stink bug damage was negatively correlated to husk extension, but not to either silk maysin levels or husk tightness. In combination with the best agronomic trait ratings that show the least corn earworm and stink bug damage, lowest smut infection rate, and good insect-resistant phenotypic traits (i.e., high maysin and good husk coverage and husk tightness), 10 best inbred lines (CML90, CML92, CML94, CML99, CML104, CML108, CML114, CML128, CML137, and CML373) were identified from the 94 lines examined. These selected inbred lines will be used for further examination of their resistance mechanisms and development of new corn germplasm that confers multiple ear-colonizing pest resistance.

  17. Efficacy of Silk Channel Injections with Insecticides for Management of Lepidoptera Pests of Sweet Corn.

    Science.gov (United States)

    Sparks, A N; Gadal, L; Ni, X

    2015-08-01

    The primary Lepidoptera pests of sweet corn (Zea mays L. convar. saccharata) in Georgia are the corn earworm, Helicoverpa zea (Boddie), and the fall armyworm, Spodoptera frugiperda (J. E. Smith). Management of these pests typically requires multiple insecticide applications from first silking until harvest, with commercial growers frequently spraying daily. This level of insecticide use presents problems for small growers, particularly for "pick-your-own" operations. Injection of oil into the corn ear silk channel 5-8 days after silking initiation has been used to suppress damage by these insects. Initial work with this technique in Georgia provided poor results. Subsequently, a series of experiments was conducted to evaluate the efficacy of silk channel injections as an application methodology for insecticides. A single application of synthetic insecticide, at greatly reduced per acre rates compared with common foliar applications, provided excellent control of Lepidoptera insects attacking the ear tip and suppressed damage by sap beetles (Nitidulidae). While this methodology is labor-intensive, it requires a single application of insecticide at reduced rates applied ∼2 wk prior to harvest, compared with potential daily applications at full rates up to the day of harvest with foliar insecticide applications. This methodology is not likely to eliminate the need for foliar applications because of other insect pests which do not enter through the silk channel or are not affected by the specific selective insecticide used in the silk channel injection, but would greatly reduce the number of applications required. This methodology may prove particularly useful for small acreage growers. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. 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

  19. 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.

  20. Spatial patterns of aflatoxin levels in relation to ear-feeding insect damage in pre-harvest corn.

    Science.gov (United States)

    Ni, Xinzhi; Wilson, Jeffrey P; Buntin, G David; Guo, Baozhu; Krakowsky, Matthew D; Lee, R Dewey; Cottrell, Ted E; Scully, Brian T; Huffaker, Alisa; Schmelz, Eric A

    2011-07-01

    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 discussed.

  1. 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. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Field screening of experimental corn hybrids and inbred lines for multiple ear-feeding insect resistance.

    Science.gov (United States)

    Ni, Xinzhi; Xu, Wenwei; Krakowsky, Matthew D; Buntin, G David; Brown, Steve L; Lee, R Dewey; Coy, Anton E

    2007-10-01

    Identifying and using native insect resistance genes is the core of integrated pest management. In this study, 10 experimental corn, Zea mays L., hybrids and 10 inbred lines were screened for resistance to major ear-feeding insects in the southeastern Coastal Plain region of the United States during 2004 and 2005. Ear-feeding insect damage was assessed at harvest by visual damage rating for the corn earworm, Helicoverpa zea (Boddie), and by the percentage of kernels damaged by the maize weevil, Sitophilus zeamais Motschulsky, and stink bugs [combination of Euschistus servus (Say) and southern green stink bug, Nezara viridula (L.)]. Among the eight inbred lines and two control populations examined, C3S1B73-5b was resistant to corn earworm, maize weevil, and stink bugs. In contrast, C3S1B73-4 was resistant to corn earworm and stink bugs, but not to maize weevil. In a similar manner, the corn hybrid S1W*CML343 was resistant to all three ear-feeding insects, whereas hybrid C3S1B73-3*Tx205 was resistant to corn earworm and maize weevil in both growing seasons, but susceptible to stink bugs in 2005. The silk-feeding bioassay showed that corn earworm developed better on corn silk than did fall armyworm. Among all phenotypic traits examined (i.e., corn ear size, husk extension, and husk tightness), only corn ear size was negatively correlated to corn earworm damage in the inbred lines examined, whereas only husk extension (i.e., coverage) was negatively correlated to both corn earworm and maize weevil damage on the experimental hybrids examined. Such information could be used to establish a baseline for developing agronomically elite corn germplasm that confers multiple ear-feeding insect resistance.

  3. Metabolic engineering of monoterpene biosynthesis in tomato fruits via introduction of the non-canonical substrate neryl diphosphate.

    Science.gov (United States)

    Gutensohn, Michael; Nguyen, Thuong T H; McMahon, Richard D; Kaplan, Ian; Pichersky, Eran; Dudareva, Natalia

    2014-07-01

    Recently it was shown that monoterpenes in tomato trichomes (Solanum lycopersicum) are synthesized by phellandrene synthase 1 (PHS1) from the non-canonical substrate neryl diphosphate (NPP), the cis-isomer of geranyl diphosphate (GPP). As PHS1 accepts both NPP and GPP substrates forming different monoterpenes, it was overexpressed in tomato fruits to test if NPP is also available in a tissue highly active in carotenoid production. However, transgenic fruits overexpressing PHS1 produced only small amounts of GPP-derived PHS1 monoterpene products, indicating the absence of endogenous NPP. Therefore, NPP formation was achieved by diverting the metabolic flux from carotenoids via expression of tomato neryl diphosphate synthase 1 (NDPS1). NDPS1 transgenic fruits produced NPP-derived monoterpenes, including nerol, neral and geranial, while displaying reduced lycopene content. NDPS1 co-expression with PHS1 resulted in a monoterpene blend, including β-phellandrene, similar to that produced from NPP by PHS1 in vitro and in trichomes. Unexpectedly, PHS1×NDPS1 fruits showed recovery of lycopene levels compared to NDPS1 fruits, suggesting that redirection of metabolic flux is only partially responsible for the reduction in carotenoids. In vitro assays demonstrated that NPP serves as an inhibitor of geranylgeranyl diphosphate synthase, thus its consumption by PHS1 leads to recovery of lycopene levels. Monoterpenes produced in PHS1×NDPS1 fruits contributed to direct plant defense negatively affecting feeding behavior of the herbivore Helicoverpa zea and displaying antifungal activity against Botrytis cinerea. These results show that NPP-derived terpenoids can be produced in plant tissues; however, NPP has to be consumed to avoid negative impacts on plant metabolism. Copyright © 2014 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  4. How predictable are the behavioral responses of insects to herbivore induced changes in plants? Responses of two congeneric thrips to induced cotton plants.

    Directory of Open Access Journals (Sweden)

    Rehan Silva

    Full Text Available Changes in plants following insect attack are referred to as induced responses. These responses are widely viewed as a form of defence against further insect attack. In the current study we explore whether it is possible to make generalizations about induced plant responses given the unpredictability and variability observed in insect-plant interactions. Experiments were conducted to test for consistency in the responses of two congeneric thrips, Frankliniella schultzei Trybom and Frankliniella occidentalis Pergrande (Thysanoptera: Thripidae to cotton seedlings (Gossypium hirsutum Linneaus (Malvales: Malvaceae damaged by various insect herbivores. In dual-choice experiments that compared intact and damaged cotton seedlings, F. schultzei was attracted to seedlings damaged by Helicoverpa armigera (Hübner (Lepidoptera: Noctuidae, Tetranychus urticae (Koch (Trombidiforms: Tetranychidae, Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae, F. schultzei and F. occidentalis but not to mechanically damaged seedlings. In similar tests, F. occidentalis was attracted to undamaged cotton seedlings when simultaneously exposed to seedlings damaged by H. armigera, T. molitor or F. occidentalis. However, when exposed to F. schultzei or T. urticae damaged plants, F. occidentalis was more attracted towards damaged plants. A quantitative relationship was also apparent, F. schultzei showed increased attraction to damaged seedlings as the density of T. urticae or F. schultzei increased. In contrast, although F. occidentalis demonstrated increased attraction to plants damaged by higher densities of T. urticae, there was a negative relationship between attraction and the density of damaging conspecifics. Both species showed greater attraction to T. urticae damaged seedlings than to seedlings damaged by conspecifics. Results demonstrate that the responses of both species of thrips were context dependent, making generalizations difficult to formulate.

  5. 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.

  6. 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. Copyright 1998 Academic Press.

  7. 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.

  8. 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. Copyright 2000 Academic Press.

  9. 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.

  10. Transgenic cotton coexpressing Vip3A and Cry1Ac has a broad insecticidal spectrum against lepidopteran pests.

    Science.gov (United States)

    Chen, Wen-Bo; Lu, Guo-Qing; Cheng, Hong-Mei; Liu, Chen-Xi; Xiao, Yu-Tao; Xu, Chao; Shen, Zhi-Cheng; Wu, Kong-Ming

    2017-10-01

    Although farmers in China have grown transgenic Bt-Cry1Ac cotton to resist the major pest Helicoverpa armigera since 1997 with great success, many secondary lepidopteran pests that are tolerant to Cry1Ac are now reported to cause considerable economic damage. Vip3AcAa, a chimeric protein with the N-terminal part of Vip3Ac and the C-terminal part of Vip3Aa, has a broad insecticidal spectrum against lepidopteran pests and has no cross resistance to Cry1Ac. In the present study, we tested insecticidal activities of Vip3AcAa against Spodoptera litura, Spodoptera exigua, and Agrotis ipsilon, which are relatively tolerant to Cry1Ac proteins. The bioassay results showed that insecticidal activities of Vip3AcAa against these three pests are superior to Cry1Ac, and after an activation pretreatment, Vip3AcAa retained insecticidal activity against S. litura, S. exigua and A. ipsilon that was similar to the unprocessed protein. The putative receptor for this chimeric protein in the brush border membrane vesicle (BBMV) in the three pests was also identified using biotinylated Vip3AcAa toxin. To broaden Bt cotton activity against a wider spectrum of pests, we introduced the vip3AcAa and cry1Ac genes into cotton. Larval mortality rates for S. litura, A. ipsilon and S. exigua that had fed on this new cotton increased significantly compared with larvae fed on non-Bt cotton and Bt-Cry1Ac cotton in a laboratory experiment. These results suggested that the Vip3AcAa protein is an excellent option for a "pyramid" strategy for integrated pest management in China. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. 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.

  12. Biocontrol Potential of Steinernema thermophilum and Its Symbiont Xenorhabdus indica Against Lepidopteran Pests: Virulence to Egg and Larval Stages.

    Science.gov (United States)

    Kalia, Vinay; Sharma, Garima; Shapiro-Ilan, David I; Ganguly, Sudershan

    2014-03-01

    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 host susceptibility of lepidopteran larvae to S. thermophilum, based on the LC50 36 hr after treatment, G. mellonella (LC50 = 16.28 IJ/larva) was found to be more susceptible than S. litura (LC50 = 85 IJ/larva), whereas neither host was found to be significantly different from H. armigera (LC50 = 54.68 IJ/larva). In addition to virulence to the larval stages, ovicidal activity up to 84% was observed at 200 IJ/50 and 100 eggs of H. armigera and S. litura, respectively. To our knowledge this is the first report of entomopathogenic nematode pathogenicity to lepidopteran eggs. Production of infective juvenile (IJ) nematodes/insect larva was also measured and found to be positively correlated with rate of IJ for H. armigera (r = 0.990), S. litura (r = 0.892), as well as G. mellonella (r = 0.834). Both Phase I and Phase II of symbiotic bacteria Xenorhabdus indica were tested separately against neonates of H. armigera and S. litura by feeding assays and found to be virulent to the target pests; phase variation did not affect the level of virulence. Thus S. thermophilum as well as the nematode's symbiotic bacteria applied separately have the potential to be developed as biocontrol agents for key lepidopteran pests.

  13. 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.

  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. Role of tomato lipoxygenase D in wound-induced jasmonate biosynthesis and plant immunity to insect herbivores.

    Science.gov (United States)

    Yan, Liuhua; Zhai, Qingzhe; Wei, Jianing; Li, Shuyu; Wang, Bao; Huang, Tingting; Du, Minmin; Sun, Jiaqiang; Kang, Le; Li, Chang-Bao; Li, Chuanyou

    2013-01-01

    In response to insect attack and mechanical wounding, plants activate the expression of genes involved in various defense-related processes. A fascinating feature of these inducible defenses is their occurrence both locally at the wounding site and systemically in undamaged leaves throughout the plant. Wound-inducible proteinase inhibitors (PIs) in tomato (Solanum lycopersicum) provide an attractive model to understand the signal transduction events leading from localized injury to the systemic expression of defense-related genes. Among the identified intercellular molecules in regulating systemic wound response of tomato are the peptide signal systemin and the oxylipin signal jasmonic acid (JA). The systemin/JA signaling pathway provides a unique opportunity to investigate, in a single experimental system, the mechanism by which peptide and oxylipin signals interact to coordinate plant systemic immunity. Here we describe the characterization of the tomato suppressor of prosystemin-mediated responses8 (spr8) mutant, which was isolated as a suppressor of (pro)systemin-mediated signaling. spr8 plants exhibit a series of JA-dependent immune deficiencies, including the inability to express wound-responsive genes, abnormal development of glandular trichomes, and severely compromised resistance to cotton bollworm (Helicoverpa armigera) and Botrytis cinerea. Map-based cloning studies demonstrate that the spr8 mutant phenotype results from a point mutation in the catalytic domain of TomLoxD, a chloroplast-localized lipoxygenase involved in JA biosynthesis. We present evidence that overexpression of TomLoxD leads to elevated wound-induced JA biosynthesis, increased expression of wound-responsive genes and, therefore, enhanced resistance to insect herbivory attack and necrotrophic pathogen infection. These results indicate that TomLoxD is involved in wound-induced JA biosynthesis and highlight the application potential of this gene for crop protection against insects and

  16. Role of tomato lipoxygenase D in wound-induced jasmonate biosynthesis and plant immunity to insect herbivores.

    Directory of Open Access Journals (Sweden)

    Liuhua Yan

    Full Text Available In response to insect attack and mechanical wounding, plants activate the expression of genes involved in various defense-related processes. A fascinating feature of these inducible defenses is their occurrence both locally at the wounding site and systemically in undamaged leaves throughout the plant. Wound-inducible proteinase inhibitors (PIs in tomato (Solanum lycopersicum provide an attractive model to understand the signal transduction events leading from localized injury to the systemic expression of defense-related genes. Among the identified intercellular molecules in regulating systemic wound response of tomato are the peptide signal systemin and the oxylipin signal jasmonic acid (JA. The systemin/JA signaling pathway provides a unique opportunity to investigate, in a single experimental system, the mechanism by which peptide and oxylipin signals interact to coordinate plant systemic immunity. Here we describe the characterization of the tomato suppressor of prosystemin-mediated responses8 (spr8 mutant, which was isolated as a suppressor of (prosystemin-mediated signaling. spr8 plants exhibit a series of JA-dependent immune deficiencies, including the inability to express wound-responsive genes, abnormal development of glandular trichomes, and severely compromised resistance to cotton bollworm (Helicoverpa armigera and Botrytis cinerea. Map-based cloning studies demonstrate that the spr8 mutant phenotype results from a point mutation in the catalytic domain of TomLoxD, a chloroplast-localized lipoxygenase involved in JA biosynthesis. We present evidence that overexpression of TomLoxD leads to elevated wound-induced JA biosynthesis, increased expression of wound-responsive genes and, therefore, enhanced resistance to insect herbivory attack and necrotrophic pathogen infection. These results indicate that TomLoxD is involved in wound-induced JA biosynthesis and highlight the application potential of this gene for crop protection against

  17. Combination of plant and insect eggs as food sources facilitates ovarian development in an omnivorous bug Apolygus lucorum (Hemiptera: Miridae).

    Science.gov (United States)

    Yuan, Wei; Li, Wenjing; Li, Yunhe; Wu, Kongming G

    2013-06-01

    Diet nutrient is considered as an important regulatory factor for reproduction of insects. To understand the effect of different food sources on the reproductive physiology of Apolygus lucorum (Meyer-Dür), the ovarian development in adult females was investigated when they were fed on green beans (Gb), combination of green beans Phaseolus vulgaris L and Helicoverpa armigera eggs (GbHe), or H. armigera eggs (He). A female of A. lucorum has two ovaries, and each ovary contained seven yellowish ovarioles. Females fed on Gb or GbHe had larger ovaries and the ovarioles contained larger numbers of oocytes compared with those fed on He. Females in GeHe treatment has significantly higher number of follicles per ovary throughout the whole adult period compared with those in Gb or He treatment. Furthermore, the length of the best developed ovariole was affected by the diet type. The females fed on GbHe had the most developed ovarioles, with significantly longer ovarioles than those fed on Gb or He. A method was described to quantitatively score the degree of ovarian development in the current study. Similarly, the ovarian development scores were significantly higher for females in GbHe treatment than those in other two diet treatments. The ovarian development significantly delayed for females fed on He. Our results demonstrate that A. lucorum, as an omnivorous insect species, can acquire nutrients from both plant and animal origin food sources, and the combination of plants and animal food sources can significantly facilitate the ovary development of its females.

  18. Chlorantraniliprole as a candidate pesticide used in combination with the attracticides for lepidopteran moths.

    Science.gov (United States)

    Liu, Yongqiang; Gao, Yu; Liang, Gemei; Lu, Yanhui

    2017-01-01

    Methomyl is currently used as a toxicant for the attracticide BioAttract in cotton and vegetables in China. However, methomyl is highly toxic to non-target organisms and a more environmental friendly acceptable alternative is required. Larvae of three lepidopteran insects Helicoverpa armigera, Agrotis ipsilon and Spodoptera litura are important pests of these crops in China. In the present study, the toxicity of 23 commonly used insecticides were tested on H. armigera, then tested the susceptibility of A. ipsilon and S. litura moths to the insecticides which were the most toxic to H. armigera, and the acute toxicity of the most efficacious insecticides were further investigated under laboratory conditions. Chlorantraniliprole, emamectin benzoate, spinetoram, spinosad and methomyl exhibited high levels of toxicity to H. armigera moths with a mortality of 86.67%, 91.11%, 73.33%, 57.78% and 80.00%, respectively, during 24 h period at the concentration of 1 mg a.i. L-1. Among these five insecticides, A. ipsilon and S. litura moths were more sensitive to chlorantraniliprole, emamectin benzoate and methomyl. The lethal time (LT50) values of chlorantraniliprole and methomyl were shorter than emamectin benzoate for all three lepidopteran moth species at 1000 mg a.i. L-1 compared to concentrations of 500, 100 and 1 mg a.i L-1. Chlorantraniliprole was found to have similar levels of toxicity and lethal time on the three lepidopteran moths tested to the standard methomyl, and therefore, can be used as an alternative insecticide to methomyl in the attracticide for controlling these pest species.

  19. cDNA cloning and sequence determination of the pheromone biosynthesis activating neuropeptide from the seabuckthorn carpenterworm, Holcocerus hippophaecolus (Lepidoptera: Cossidae).

    Science.gov (United States)

    Li, Juan; Zhou, Jiao; Sun, Rongbo; Zhang, Haolin; Zong, Shixiang; Luo, Youqing; Sheng, Xia; Weng, Qiang

    2013-04-01

    The PBAN (pheromone biosynthesis activating neuropeptide)/pyrokinin peptides comprise a major neuropeptide family characterized by a common FXPRL amide at the C-terminus. These peptides are actively involved in many essential endocrine functions. For the first time, we reported the cDNA cloning and sequence determination of the PBAN from the seabuckthorn carpenterworm, Holcocerus hippophaecolus, by using rapid amplification of cDNA ends. The full-length cDNA of Hh-DH-PBAN contained five peptides: diapause hormone (DH) homolog, α-neuropeptide (NP), β-NP, PBAN, and γ-NP. All of the peptides were amidated at their C-terminus and shared a conserved motif, FXPR (or K) L. Moreover, Hh-DH-PBAN had high homology to the other members of the PBAN peptide family: 56% with Manduca sexta, 66% with Bombyx mori, 77% with Helicoverpa zea, and 47% with Plutella xylostella. Phylogenetic analysis revealed that Hh-DH-PBAN was closely related to PBANs from Noctuidae, demonstrated by the relatively higher similarity compared with H. zea. In addition, real-time quantitative PCR (qRT-PCR) analysis showed that Hh-DH-PBAN mRNA expression peaked in the brain-subesophageal ganglion (Br-SOG) complex, and was also detected at high levels during larval and adult stages. The expression decreased significantly after pupation. These results provided information concerning molecular structure characteristics of Hh-DH-PBAN, whose expression profile suggested that the Hh-DH-PBAN gene might be correlated with larval development and sex pheromone biosynthesis in females of the H. hippophaecolus. 2013 Wiley Periodicals, Inc

  20. Comparative venom toxicity between Pteromalus puparum and Nasonia vitripennis (Hymenoptera: Pteromalidae) toward the hemocytes of their natural hosts, non-target insects and cultured insect cells.

    Science.gov (United States)

    Zhang, Zhong; Ye, Gong-Yin; Cai, Jun; Hu, Cui

    2005-09-01

    Crude venoms from two parasitoid species, Pteromalus puparum and Nasonia vitripennis (Hymenoptera: Pteromalidae) were assayed for biological activities toward hemocytes from two species of their natural hosts and eight species of their non-natural hosts as well as two lines of cultured Lepidoptera cells, respectively. By inhibiting the spreading and viability of insect hemocytes, the venom from P. puparum displayed significantly higher activities toward plasmatocytes and granular cells from both larvae and pupae of two natural hosts, Pieris rapae and Papilio xuthus, and lower activity toward those from Spodoptera litura, Musca domestica and Sarcophaga peregrina. However, no effect was found towards any type of hemocytes from other five insects tested, namely, Ectropis oblique, Galleria mellonella, Sesamia inferens, Bombyx mori and Parnara guttata. In contrast, the venom from N. vitripennis showed a narrower range of targeted insects. It appeared to have highly adverse effects on the spreading and viability of plasmatocytes and granular cells only from the natural hosts, M. domestica and S. peregrina, little toxicity to cells from P. rapae and P. xuthus, and no effect on any of the other insects tested. Pteromalus puparum venom also apparently presented a high ability to block the spreading of Tn-5B1-4 cells derived from Trichoplusia ni, and high cytotoxicity to the cells and Ha cells derived from Helicoverpa armigera. Nasonia vitripennis venom, however, only had a marked lethal effect to Ha cells. In addition, the possibility that the host range of a defined parasitoid could be assessed using our method of treating hemocytes from candidate insects with venom in vitro, and the potential of our venoms tested in the development of bio-insecticides, insect-resistant transgenic plants, are discussed.

  1. Baseline sensitivity of maize borers in India to the Bacillus thuringiensis insecticidal proteins Cry1A.105 and Cry2Ab2.

    Science.gov (United States)

    Jalali, Sushil K; Yadavalli, Lalitha; Ojha, Rakshit; Kumar, Pradyumn; Sulaikhabeevi, Suby B; Sharma, Reema; Nair, Rupa; Kadanur, Ravi C; Kamath, Subray P; Komarlingam, Mohan S

    2015-08-01

    Among the major pests of maize in India are two stem borers, Chilo partellus (Swinhoe) and Sesamia inferens (Walker), and an earworm, Helicoverpa armigera (Hübner). As a pest control strategy, transgenic Bacillus thuringiensis (Bt) maize hybrids are undergoing regulatory trials in India. We have determined the sensitivity of the target lepidopterans to the insecticidal Bt proteins expressed in Bt maize, as this determines product efficacy and the resistance management strategy to be adopted. Maize hybrids with event MON89034 express two insecticidal Bt proteins, Cry1A.105 and Cry2Ab2. Sensitivity profiles of 53 populations of C. partellus, 21 populations of S. inferens and 21 populations of H. armigera, collected between 2008 and 2013 from maize-growing areas in India, to Cry1A.105 and Cry2Ab2 proteins were generated through dose-response assays. Cry1A.105 protein was the most effective to neonates of C. partellus (mean MIC90 range 0.30-1.0 µg mL(-1) ) and H. armigera (mean MIC90 range 0.71-8.22 µg mL(-1) ), whereas Cry2Ab2 (mean MIC90 range 0.65-1.70 µg mL(-1) ) was the most effective to S. inferens. Populations of C. partellus, S. inferens and H. armigera were susceptible to the Bt proteins Cry1A.105 and Cry2Ab2. The Bt sensitivity data will serve as precommercialisation benchmarks for resistance monitoring purposes. © 2014 Society of Chemical Industry.

  2. 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.

  3. Two Year Field Study to Evaluate the Efficacy of Mamestra brassicae Nucleopolyhedrovirus Combined with Proteins Derived from Xestia c-nigrum Granulovirus

    Directory of Open Access Journals (Sweden)

    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.

  4. Transposable elements are enriched within or in close proximity to xenobiotic-metabolizing cytochrome P450 genes

    Directory of Open Access Journals (Sweden)

    Li Xianchun

    2007-03-01

    Full Text Available Abstract Background Transposons, i.e. transposable elements (TEs, are the major internal spontaneous mutation agents for the variability of eukaryotic genomes. To address the general issue of whether transposons mediate genomic changes in environment-adaptation genes, we scanned two alleles per each of the six xenobiotic-metabolizing Helicoverpa zea cytochrome P450 loci, including CYP6B8, CYP6B27, CYP321A1, CYP321A2, CYP9A12v3 and CYP9A14, for the presence of transposon insertions by genome walking and sequence analysis. We also scanned thirteen Drosophila melanogaster P450s genes for TE insertions by in silico mapping and literature search. Results Twelve novel transposons, including LINEs (long interspersed nuclear elements, SINEs (short interspersed nuclear elements, MITEs (miniature inverted-repeat transposable elements, one full-length transib-like transposon, and one full-length Tcl-like DNA transpson, are identified from the alleles of the six H. zea P450 genes. The twelve transposons are inserted into the 5'flanking region, 3'flanking region, exon, or intron of the six environment-adaptation P450 genes. In D. melanogaster, seven out of the eight Drosophila P450s (CYP4E2, CYP6A2, CYP6A8, CYP6A9, CYP6G1, CYP6W1, CYP12A4, CYP12D1 implicated in insecticide resistance are associated with a variety of transposons. By contrast, all the five Drosophila P450s (CYP302A1, CYP306A1, CYP307A1, CYP314A1 and CYP315A1 involved in ecdysone biosynthesis and developmental regulation are free of TE insertions. Conclusion These results indicate that TEs are selectively retained within or in close proximity to xenobiotic-metabolizing P450 genes.

  5. The first report of Xenorhabdus indica from Steinernema pakistanense: co-phylogenetic study suggests co-speciation between X. indica and its steinernematid nematodes.

    Science.gov (United States)

    Bhat, A H; Chaubey, A K; Půža, V

    2018-01-17

    During a survey in agricultural fields of the sub-humid region of Meerut district, India, two strains of entomopathogenic nematodes, labelled CS31 and CS32, were isolated using the Galleria baiting technique. Based on morphological and morphometric studies, and molecular data, the nematodes were identified as Steinernema pakistanense, making this finding the first report of this species from India. For the first time, we performed a molecular and biochemical characterization of the bacterial symbiont of S. pakistanense. Furthermore, a co-phylogenetic analysis of the bacteria from the monophyletic clade containing a symbiont of S. pakistanense, together with their nematode hosts, was conducted, to test the degree of nematode-bacteria co-speciation. Both isolates were also tested in a laboratory assay for pathogenicity against two major pests, Helicoverpa armigera and Spodoptera litura. The morphology of the Indian isolates corresponds mainly to the original description, with the only difference being the absence of a mucron in first-generation females and missing epiptygmata in the second generation. The sequences of bacterial recA and gyrB genes have shown that the symbiont of S. pakistanense is closely related to Xenorhabdus indica, which is associated with some other nematodes from the 'bicornutum' group. Co-phylogenetic analysis has shown a remarkable congruence between the nematode and bacterial phylogenies, suggesting that, in some lineages within the Steinernema / Xenorhabdus complex, the nematodes and bacteria have undergone co-speciation. In the virulence assay, both strains caused a 100% mortality of both tested insects after 48 h, even at the lowest doses of 25 infective juveniles per insect, suggesting that S. pakistanense could be considered for use in the biocontrol of these organisms in India.

  6. 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. Copyright © 2016

  7. 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.

  8. EVALUATION OF FOUR INTEGRATED PEST MANAGEMENT PACKAGES FOR CONTROLLING MAIN PESTS OF COTTON IN RAINFED FIELDS

    Directory of Open Access Journals (Sweden)

    Nurindah Nurindah

    2014-04-01

    Full Text Available Cotton production nationally is low due to various constraints, including pests. Two main pests commonly found in cotton plantation in rain fed fields are cotton leafhopper (Amrasca biguttula and cotton bollworm (Helicoverpa armigera. The study aimed to evaluate four packages of integrated pest management (IPM techniques to control cotton leafhopper and cotton bollworm in rain fed fields. The experiment was conducted in farmers’ fields at Asembagus, East Java, between January and July 2012. Four packages of IPM evaluated were cotton varieties, i.e. Kanesia 10 or Kanesia 13, and seed treatment with synthetic insecticide (imidacloprid before sowing or spraying molasses (10 ml L-1 water as food for natural enemies. The cotton plants were intercropped with groundnut and sprayed with neem seed extract (NSE at the action threshold level for pest control. These packages were compared among themselves and also with the methods usually used by farmers, i.e. planting cotton variety Kanesia 8 intercropped with groundnut and pest control using synthetic chemical insecticides. Twenty five plants were sampled randomly per plot and measured for their growth, leafhopper and  bollworm populations, as well as cotton seed yield per plot. Observations were made weekly, starting at 30 days after planting (DAP until 120 DAP. The results showed that the use of Kanesia 10 or Kanesia 13 intercropped with groundnut and spraying molasses to conserve natural enemies was the best  pest management practice and superior to farmers’ practices. Conserving natural enemies is not only profitable (saving production cost of IDR1,150,000 to IDR1,500,000 ha-1 season-1, but also safe for the environment (no need to spray chemical insecticides.

  9. Non-recessive Bt toxin resistance conferred by an intracellular cadherin mutation in field-selected populations of cotton bollworm.

    Directory of Open Access Journals (Sweden)

    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.

  10. Manthar-03: a high-yielding cultivar of wheat released for general cultivation in Southern Punjab

    International Nuclear Information System (INIS)

    Hussain, M.; Akhtar, L.H.; Nasim, M.

    2010-01-01

    We report the release of a new wheat variety Manthar-03. 'Manthar-03' is a high yielding and rust resistant variety of bread wheat with erect growth habit. It was released in the year 2003 as a general purpose variety. Manthar-03 is a selection from CIMMYT material (Entry No. 42 of 29 International Bread Wheat Screening Nursery) made at Regional Agricultural Research Institute (RARI), Bahawalpur during 1996-97. This strain has the famous CIMMYT line 'Kauz' in its parentage (KAUZ//ALTAR 84/AOS). Its pedigree is CM11163-6M-20Y-10M- 0M-0B. It is a more adapted and a high yielder. Genetically, this strain differs from existing commercial cultivars of Punjab. Resistance against leaf rust (5MRMS to 10MR), RRI value of 6.7 and 7.6 for leaf rust and ACI values of 3.4 and 0.7 for leaf rust) and high yield potential (6300 kg ha-1 ) are the major attributes of Manthar-03 that make it a superior variety for its target regions. Manthar-03 is tolerant to wheat aphid and Helicoverpa armigera. The thousand seed weight of this variety is 40-44 g. Seed is amber in color and contains 12.97% protein, 8.2% dry gluten and 1.55% ash. It has good chapati making quality. Plant type of Manthar-03 is erect with plant height 94 cm and droopy flag leaves. It is lodging resistant. It completes heading in 98 days and matures in 142 days. Manthar-03 performs better when planted from 15, November to 1, December, keeping 125 kg ha/sup -1/ seed rate and 125-85-50 kg NPK ha/sup -1/ are applied. (author)

  11. Spatial Patterns of Aflatoxin Levels in Relation to Ear-Feeding Insect Damage in Pre-Harvest Corn

    Science.gov (United States)

    Ni, Xinzhi; Wilson, Jeffrey P.; Buntin, G. David; Guo, Baozhu; Krakowsky, Matthew D.; Lee, R. Dewey; Cottrell, Ted E.; Scully, Brian T.; Huffaker, Alisa; Schmelz, Eric A.

    2011-01-01

    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 discussed. PMID

  12. 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.

  13. Regional pest suppression associated with widespread Bt maize adoption benefits vegetable growers.

    Science.gov (United States)

    Dively, Galen P; Venugopal, P Dilip; Bean, Dick; Whalen, Joanne; Holmstrom, Kristian; Kuhar, Thomas P; Doughty, Hélène B; Patton, Terry; Cissel, William; Hutchison, William D

    2018-03-27

    Transgenic crops containing the bacterium Bacillus thuringiensis (Bt) genes reduce pests and insecticide usage, promote biocontrol services, and economically benefit growers. Area-wide Bt adoption suppresses pests regionally, with declines expanding beyond the planted Bt crops into other non-Bt crop fields. However, the offsite benefits to growers of other crops from such regional suppression remain uncertain. With data spanning 1976-2016, we demonstrate that vegetable growers benefit via decreased crop damage and insecticide applications in relation to pest suppression in the Mid-Atlantic United States. We provide evidence for the regional suppression of Ostrinia nubilalis (Hübner), European corn borer, and Helicoverpa zea (Boddie), corn earworm, populations in association with widespread Bt maize adoption (1996-2016) and decreased economic levels for injury in vegetable crops [peppers ( Capsicum annuum L.), green beans ( Phaseolus vulgaris L.), and sweet corn ( Zea mays L., convar. saccharata )] compared with the pre-Bt period (1976-1995). Moth populations of both species significantly declined in association with widespread Bt maize (field corn) adoption, even as increased temperatures buffered the population reduction. We show marked decreases in the number of recommended insecticidal applications, insecticides applied, and O. nubilalis damage in vegetable crops in association with widespread Bt maize adoption. These offsite benefits to vegetable growers in the agricultural landscape have not been previously documented, and the positive impacts identified here expand on the reported ecological effects of Bt adoption. Our results also underscore the need to account for offsite economic benefits of pest suppression, in addition to the direct economic benefits of Bt crops.

  14. Associations of planting date, drought stress, and insects with Fusarium ear rot and fumonisin B1 contamination in California maize.

    Science.gov (United States)

    Parsons, M W; Munkvold, G P

    2010-05-01

    Fusarium ear rot, caused by Fusarium verticillioides, is one of the most common diseases of maize, causing yield and quality reductions and contamination of grain by fumonisins and other mycotoxins. Drought stress and various insects have been implicated as factors affecting disease severity. Field studies were conducted to evaluate the interactions and relative influences of drought stress, insect infestation, and planting date upon Fusarium ear rot severity and fumonisin B1 contamination. Three hybrids varying in partial resistance to Fusarium ear rot were sown on three planting dates and subjected to four irrigation regimes to induce differing levels of drought stress. A foliar-spray insecticide treatment was imposed to induce differing levels of insect injury. Populations of thrips (Frankliniella spp.), damage by corn earworm (Helicoverpa zeae), Fusarium ear rot symptoms, and fumonisin B1 levels were assessed. There were significant effects of hybrid, planting date, insecticide treatment, and drought stress on Fusarium ear rot symptoms and fumonisin B1 contamination, and these factors also had significant interacting effects. The most influential factors were hybrid and insecticide treatment, but their effects were influenced by planting date and drought stress. The more resistant hybrids and the insecticide-treated plots consistently had lower Fusarium ear rot severity and fumonisin B1 contamination. Later planting dates typically had higher thrips populations, more Fusarium ear rot, and higher levels of fumonisin B1. Insect activity was significantly correlated with disease severity and fumonisin contamination, and the correlations were strongest for thrips. The results of this study confirm the influence of thrips on Fusarium ear rot severity in California, USA, and also establish a strong association between thrips and fumonisin B1 levels.

  15. High-efficiency Agrobacterium-mediated transformation of chickpea (Cicer arietinum L.) and regeneration of insect-resistant transgenic plants.

    Science.gov (United States)

    Mehrotra, Meenakshi; Sanyal, Indraneel; Amla, D V

    2011-09-01

    To develop an efficient genetic transformation system of chickpea (Cicer arietinum L.), callus derived from mature embryonic axes of variety P-362 was transformed with Agrobacterium tumefaciens strain LBA4404 harboring p35SGUS-INT plasmid containing the uidA gene encoding β-glucuronidase (GUS) and the nptII gene for kanamycin selection. Various factors affecting transformation efficiency were optimized; as Agrobacterium suspension at OD(600) 0.3 with 48 h of co-cultivation period at 20°C was found optimal for transforming 10-day-old MEA-derived callus. Inclusion of 200 μM acetosyringone, sonication for 4 s with vacuum infiltration for 6 min improved the number of GUS foci per responding explant from 1.0 to 38.6, as determined by histochemical GUS assay. For introducing the insect-resistant trait into chickpea, binary vector pRD400-cry1Ac was also transformed under optimized conditions and 18 T(0) transgenic plants were generated, representing 3.6% transformation frequency. T(0) transgenic plants reflected Mendelian inheritance pattern of transgene segregation in T(1) progeny. PCR, RT-PCR, and Southern hybridization analysis of T(0) and T(1) transgenic plants confirmed stable integration of transgenes into the chickpea genome. The expression level of Bt-Cry protein in T(0) and T(1) transgenic chickpea plants was achieved maximum up to 116 ng mg(-1) of soluble protein, which efficiently causes 100% mortality to second instar larvae of Helicoverpa armigera as analyzed by an insect mortality bioassay. Our results demonstrate an efficient and rapid transformation system of chickpea for producing non-chimeric transgenic plants with high frequency. These findings will certainly accelerate the development of chickpea plants with novel traits.

  16. Whole genome re-sequencing reveals genome-wide variations among parental lines of 16 mapping populations in chickpea (Cicer arietinum L.).

    Science.gov (United States)

    Thudi, Mahendar; Khan, Aamir W; Kumar, Vinay; Gaur, Pooran M; Katta, Krishnamohan; Garg, Vanika; Roorkiwal, Manish; Samineni, Srinivasan; Varshney, Rajeev K

    2016-01-27

    Chickpea (Cicer arietinum L.) is the second most important grain legume cultivated by resource poor farmers in South Asia and Sub-Saharan Africa. In order to harness the untapped genetic potential available for chickpea improvement, we re-sequenced 35 chickpea genotypes representing parental lines of 16 mapping populations segregating for abiotic (drought, heat, salinity), biotic stresses (Fusarium wilt, Ascochyta blight, Botrytis grey mould, Helicoverpa armigera) and nutritionally important (protein content) traits using whole genome re-sequencing approach. A total of 192.19 Gb data, generated on 35 genotypes of chickpea, comprising 973.13 million reads, with an average sequencing depth of ~10 X for each line. On an average 92.18 % reads from each genotype were aligned to the chickpea reference genome with 82.17 % coverage. A total of 2,058,566 unique single nucleotide polymorphisms (SNPs) and 292,588 Indels were detected while comparing with the reference chickpea genome. Highest number of SNPs were identified on the Ca4 pseudomolecule. In addition, copy number variations (CNVs) such as gene deletions and duplications were identified across the chickpea parental genotypes, which were minimum in PI 489777 (1 gene deletion) and maximum in JG 74 (1,497). A total of 164,856 line specific variations (144,888 SNPs and 19,968 Indels) with the highest percentage were identified in coding regions in ICC 1496 (21 %) followed by ICCV 97105 (12 %). Of 539 miscellaneous variations, 339, 138 and 62 were inter-chromosomal variations (CTX), intra-chromosomal variations (ITX) and inversions (INV) respectively. Genome-wide SNPs, Indels, CNVs, PAVs, and miscellaneous variations identified in different mapping populations are a valuable resource in genetic research and helpful in locating genes/genomic segments responsible for economically important traits. Further, the genome-wide variations identified in the present study can be used for developing high density SNP arrays for

  17. c-di-GMP Regulates Various Phenotypes and Insecticidal Activity of Gram-Positive Bacillus thuringiensis

    Directory of Open Access Journals (Sweden)

    Yang Fu

    2018-02-01

    Full Text Available C-di-GMP has been well investigated to play significant roles in the physiology of many Gram-negative bacteria. However, its effect on Gram-positive bacteria is less known. In order to more understand the c-di-GMP functions in Gram-positive bacteria, we have carried out a detailed study on the c-di-GMP-metabolizing enzymes and their physiological functions in Bacillus thuringiensis, a Gram-positive entomopathogenic bacterium that has been applied as an insecticide successfully. We performed a systematic study on the ten putative c-di-GMP-synthesizing enzyme diguanylate cyclases (DGCs and c-di-GMP-degrading enzyme phosphodiesterases (PDEs in B. thuringiensis BMB171, and artificially elevated the intracellular c-di-GMP level in BMB171 by deleting one or more pde genes. We found increasing level of intracellular c-di-GMP exhibits similar activities as those in Gram-negative bacteria, including altered activities in cell motility, biofilm formation, and cell-cell aggregation. Unexpectedly, we additionally found a novel function exhibited by the increasing level of c-di-GMP to promote the insecticidal activity of this bacterium against Helicoverpa armigera. Through whole-genome transcriptome profile analyses, we found that 4.3% of the B. thuringiensis genes were differentially transcribed when c-di-GMP level was increased, and 77.3% of such gene products are involved in some regulatory pathways not reported in other bacteria to date. In summary, our study represents the first comprehensive report on the c-di-GMP-metabolizing enzymes, their effects on phenotypes, and the transcriptome mediated by c-di-GMP in an important Gram-positive bacterium.

  18. A moth pheromone brewery: production of (Z)-11-hexadecenol by heterologous co-expression of two biosynthetic genes from a noctuid moth in a yeast cell factory.

    Science.gov (United States)

    Hagström, Åsa K; Wang, Hong-Lei; Liénard, Marjorie A; Lassance, Jean-Marc; Johansson, Tomas; Löfstedt, Christer

    2013-12-13

    Moths (Lepidoptera) are highly dependent on chemical communication to find a mate. Compared to conventional unselective insecticides, synthetic pheromones have successfully served to lure male moths as a specific and environmentally friendly way to control important pest species. However, the chemical synthesis and purification of the sex pheromone components in large amounts is a difficult and costly task. The repertoire of enzymes involved in moth pheromone biosynthesis in insecta can be seen as a library of specific catalysts that can be used to facilitate the synthesis of a particular chemical component. In this study, we present a novel approach to effectively aid in the preparation of semi-synthetic pheromone components using an engineered vector co-expressing two key biosynthetic enzymes in a simple yeast cell factory. We first identified and functionally characterized a ∆11 Fatty-Acyl Desaturase and a Fatty-Acyl Reductase from the Turnip moth, Agrotis segetum. The ∆11-desaturase produced predominantly Z11-16:acyl, a common pheromone component precursor, from the abundant yeast palmitic acid and the FAR transformed a series of saturated and unsaturated fatty acids into their corresponding alcohols which may serve as pheromone components in many moth species. Secondly, when we co-expressed the genes in the Brewer's yeast Saccharomyces cerevisiae, a set of long-chain fatty acids and alcohols that are not naturally occurring in yeast were produced from inherent yeast fatty acids, and the presence of (Z)-11-hexadecenol (Z11-16:OH), demonstrated that both heterologous enzymes were active in concert. A 100 ml batch yeast culture produced on average 19.5 μg Z11-16:OH. Finally, we demonstrated that oxidized extracts from the yeast cells containing (Z)-11-hexadecenal and other aldehyde pheromone compounds elicited specific electrophysiological activity from male antennae of the Tobacco budworm, Heliothis virescens, supporting the idea that genes from different

  19. Field-Evolved Resistance in Corn Earworm to Cry Proteins Expressed by Transgenic Sweet Corn

    Science.gov (United States)

    Dively, Galen P.; Finkenbinder, Chad

    2016-01-01

    Background Transgenic corn engineered with genes expressing insecticidal toxins from the bacterium Bacillus thuringiensis (Berliner) (Bt) are now a major tool in insect pest management. With its widespread use, insect resistance is a major threat to the sustainability of the Bt transgenic technology. For all Bt corn expressing Cry toxins, the high dose requirement for resistance management is not achieved for corn earworm, Helicoverpa zea (Boddie), which is more tolerant to the Bt toxins. Methodology/Major Findings We present field monitoring data using Cry1Ab (1996–2016) and Cry1A.105+Cry2Ab2 (2010–2016) expressing sweet corn hybrids as in-field screens to measure changes in field efficacy and Cry toxin susceptibility to H. zea. Larvae successfully damaged an increasing proportion of ears, consumed more kernel area, and reached later developmental stages (4th - 6th instars) in both types of Bt hybrids (Cry1Ab—event Bt11, and Cry1A.105+Cry2Ab2—event MON89034) since their commercial introduction. Yearly patterns of H. zea population abundance were unrelated to reductions in control efficacy. There was no evidence of field efficacy or tissue toxicity differences among different Cry1Ab hybrids that could contribute to the decline in control efficacy. Supportive data from laboratory bioassays demonstrate significant differences in weight gain and fitness characteristics between the Maryland H. zea strain and a susceptible strain. In bioassays with Cry1Ab expressing green leaf tissue, Maryland H. zea strain gained more weight than the susceptible strain at all concentrations tested. Fitness of the Maryland H. zea strain was significantly lower than that of the susceptible strain as indicated by lower hatch rate, longer time to adult eclosion, lower pupal weight, and reduced survival to adulthood. Conclusions/Significance After ruling out possible contributing factors, the rapid change in field efficacy in recent years and decreased susceptibility of H. zea to Bt

  20. Restriction fragment length polymorphism markers associated with silk maysin, antibiosis to corn earworm (Lepidoptera: Noctuidae) larvae, in a dent and sweet corn cross.

    Science.gov (United States)

    Guo, B Z; Zhang, Z J; Li, R G; Widstrom, N W; Snook, M E; Lynch, R E; Plaisted, D

    2001-04-01

    Maysin, a C-glycosylflavone in maize silk, has insecticidal activity against corn earworm, Helicoverpa zea (Boddie), larvae. Sweet corn, Zea mays L., is a vulnerable crop to ear-feeding insects and requires pesticide protection from ear damage. This study was conducted to identify maize chromosome regions associated with silk maysin concentration and eventually to transfer and develop high silk maysin sweet corn lines with marker-assisted selection (MAS). Using an F2 population derived from SC102 (high maysin dent corn) and B31857 (low maysin sh2 sweet corn), we detected two major quantitative trait loci (QTL). It was estimated that 25.6% of the silk maysin variance was associated with segregation in the genomic region of npi286 (flanking to p1) on chromosome 1S. We also demonstrated that a1 on chromosome 3L had major contribution to silk maysin (accounted for 15.7% of the variance). Locus a1 has a recessive gene action for high maysin with the presence of functional p1 allele. Markers umc66a (near c2) and umc105a on chromosome 9S also were detected in this analysis with minor contribution. A multiple-locus model, which included npi286, a1, csu3 (Bin 1.05), umc245 (Bin 7.05), agrr21 (Bin 8.09), umc105a, and the epistatic interactions npi286 x a1, a1 x agrr21, csu3 x umc245, and umc105a x umc245, accounted for 76.3% of the total silk maysin variance. Tester crosses showed that at the a1 locus, SC102 has functional A1 alleles and B31857 has homozygous recessive a1 alleles. Individuals of (SC102 x B31857) x B31857 were examined with MAS and plants with p1 allele from SC102 and homozygous a1 alleles from B31857 had consistent high silk maysin. Marker-assisted selection seems to be a suitable method to transfer silk maysin to sweet corn lines to reduce pesticide application.

  1. Impact of the Stem Extract of on the Feeding Potential and Histological Architecture of the Midgut Epithelial Tissue of Early Fourth Instars of HÜbner

    Directory of Open Access Journals (Sweden)

    Monika Mishra

    2015-01-01

    Full Text Available Helicoverpa armigera HÜbner is one of the most important agricultural crop pests in the world causing heavy crop yield losses. The continued and indiscriminate use of synthetic insecticides in agriculture for their control has received wide public apprehension because of multifarious problems, including insecticide resistance, resurgence of pest species, environmental pollution, and toxic hazards to humans and nontarget organisms. These problems have necessitated the need to explore and develop alternative strategies using eco-friendly and biodegradable plant products. In view of this, the efficacy of Thevetia neriifolia methanol stem extract was evaluated against the early fourth instars of H. armigera as an antifeedant and stomach poison agent. Feeding of larvae with the diet containing 0.005%–5.0% extract resulted in 2.06%–37.35% antifeedant index; the diet with 5.0% extract caused 54.3% reduced consumption. The negative impact of extract on larval feeding resulted in 37.5%–77.7% starvation, causing adverse effects on the larval weight. Choice between control and experimental diet resulted in feeding preference of larvae for the control diet, leading to 7.3%–42.9% reduced consumption of extract-containing diet. The only exception was the diet with 0.005% extract, which could not cause any deterrence. The midgut histological architecture of H. armigera larvae fed with 0.005%–0.05% extract-containing diet with negligible antifeedant potential showed significant damage, shrinkage, and distortion and vacuolization of gut tissues and peritrophic membrane, causing the disintegration of epithelial, goblet, and regenerative cells; the damage increased with the increase in concentration. These changes in the gut caused negative impact on the digestion and absorption of food and thus nutritional deficiency in the larvae, which could probably affect their growth and development. This study reveal the appreciable stomach poison potential of T

  2. 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

  3. Pyramids of QTLs enhance host-plant resistance and Bt-mediated resistance to leaf-chewing insects in soybean.

    Science.gov (United States)

    Ortega, María A; All, John N; Boerma, H Roger; Parrott, Wayne A

    2016-04-01

    QTL-M and QTL-E enhance soybean resistance to insects. Pyramiding these QTLs with cry1Ac increases protection against Bt-tolerant pests, presenting an opportunity to effectively deploy Bt with host-plant resistance genes. Plant resistance to leaf-chewing insects minimizes the need for insecticide applications, reducing crop production costs and pesticide concerns. In soybean [Glycine max (L.) Merr.], resistance to a broad range of leaf-chewing insects is found in PI 229358 and PI 227687. PI 229358's resistance is conferred by three quantitative trait loci (QTLs): M, G, and H. PI 227687's resistance is conferred by QTL-E. The letters indicate the soybean Linkage groups (LGs) on which the QTLs are located. This study aimed to determine if pyramiding PI 229358 and PI 227687 QTLs would enhance soybean resistance to leaf-chewing insects, and if pyramiding these QTLs with Bt (cry1Ac) enhances resistance against Bt-tolerant pests. The near-isogenic lines (NILs): Benning(ME), Benning(MGHE), and Benning(ME+cry1Ac) were developed. Benning(ME) and Benning(MGHE) were evaluated in detached-leaf and greenhouse assays with soybean looper [SBL, Chrysodeixis includens (Walker)], corn earworm [CEW, Helicoverpa zea (Boddie)], fall armyworm [FAW, Spodoptera frugiperda (J.E. Smith)], and velvetbean caterpillar [VBC, Anticarsia gemmatalis (Hübner)]; and in field-cage assays with SBL. Benning(ME+cry1Ac) was tested in detached-leaf assays against SBL, VBC, and Southern armyworm [SAW, Spodoptera eridania (Cramer)]. In the detached-leaf assay, Benning(ME) showed the strongest antibiosis against CEW, FAW, and VBC. In field-cage conditions, Benning(ME) and Benning(MGHE) suffered 61 % less defoliation than Benning. Benning(ME+cry1Ac) was more resistant than Benning(ME) and Benning (cry1Ac) against SBL and SAW. Agriculturally relevant levels of resistance in soybean can be achieved with just two loci, QTL-M and QTL-E. ME+cry1Ac could present an opportunity to protect the durability of Bt

  4. 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

  5. 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

  6. Características biológicas de parasitóide de ovos criados em diferentes hospedeiros

    Directory of Open Access Journals (Sweden)

    Ariana Lisboa Meira

    2017-04-01

    Full Text Available As espécies de Trichogramma são agentes biológicos que contribuem para o controle de lepidópteros. Objetivou-se neste trabalho identificar qual espécie de Trichogramma apresenta melhor desempenho biológico quando criados em ovos de Anagasta kuehniella (Lepidoptera: Pyralidae, Helicoverpa zea (Boddie (Lepidoptera: Noctuidae e Plutella xylostella Linnaeus (Lepidoptera: Plutellidae. Desta forma os parâmetros biológicos avaliados no período de ovo a adulto foram duração de ovo a adulto e percentual de emergência e no estágio adulto avaliou-se número de ovos parasitados, número de indivíduos por ovo e razão sexual em Trichogramma atopovirilia Oatman & Planter (Hymenoptera: Trichogrammatidae e Trichogramma exiguum Pinto & Planter (Hymenoptera: Trichogrammatidae.  Para o período de ovo a adulto, A. kuehniella, H. zea e P. xylostella não apresentaram diferença quando criados com as mesmas espécies de Trichogramma para a duração do ciclo de desenvolvimento e não houve diferença para o percentual de emergência entre os três hospedeiros em estudo. Em relação aos parâmetros avaliados no estágio adulto, para número de ovos parasitados, somente A. kuehniella, diferenciou entre as espécies de Trichogramma. O número de indivíduos por ovo, os maiores valores foram observados quando as espécies de Trichogramma foram criadas com ovos de H. zea. A razão sexual, T. atopovirilia diferiu apenas para A. kuehniella. As duas espécies de Trichogramma estão aptas a se desenvolverem nos hospedeiros A. kuehniella e P. xylostella. Contudo para o hospedeiro H. zea, T. exiguum foi à espécie que obteve melhor desempenho, parasitando maior número de ovos e obtendo maior número de indivíduos por ovo.

  7. Management of lepidopterans through irradiations

    International Nuclear Information System (INIS)

    Bhati, Dheeraj; Parvez, Asif; Kausar, Hina; Srivastava, Meera

    2012-01-01

    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)

  8. 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

  9. NÃO-PREFERÊNCIA PARA ALIMENTAÇÃO DA LAGARTA-DO-CARTUCHO EM MILHO

    Directory of Open Access Journals (Sweden)

    LUÍS CLÁUDIO PATERNO SILVEIRA

    1998-01-01

    Full Text Available O objetivo do trabalho foi avaliar a não-preferência para alimentação de lagartas de 1o e de 5o ínstares, de Spodoptera frugiperda, em quatro genótipos de milho: IAC701 N, 'IAC7777', Mp707 e Zapalote Chico (ZC. Os ensaios foram realizados em arenas, com livre chance de escolha pelas lagartas, por 24 horas. Com lagartas recém-eclodidas, 1o ínstar, observou-se não-preferência ao ZC e Mp707, nos quais se encontraram apenas 20% das lagartas, em comparação com IAC701 N e 'IAC7777', onde se concentraram 80% delas. No teste com lagartas de 5o ínstar, o consumo das seções foliares foi cerca de duas vezes maior em `IAC701 N, se comparado a `ZC' e `Mp707'. Concluiu-se que a antixenose ou não-preferência é um dos mecanismos de resistência encontrados em ZC e Mp707, materiais estrangeiros que confirmam, nas condições de Campinas, suas características de resistência.The effect of corn genotypes upon food preferences of Spodoptera frugiperda larvae was evaluated. The genotypes selected were: IAC701 N, an inbred line of Instituto Agronômico de Campinas (IAC, State of São Paulo, Brazil; 'IAC7777', a single hybrid of IAC in which the above inbred line is one of the parents; Mp707, an inbred line of Mississippi State University considered to be resistant to S. frugiperda; and Zapalote Chico (ZC, a Central American corn race referred as resistant to Helicoverpa zea and S. frugiperda. The tests were run in arenas with free choice among treatments. The test with 1st instar larvae indicated that the insects preferred to feed on the genotypes IAC701 N and IAC7777, and a lower percentage of larvae stablished on the leaves of ZC and Mp707. The test with 5th instar larvae indicated a non-preference of the larvae for the leaves of genotypes Mp707 and ZC while IAC701 N was the most preferred with more leaf area consumed. The non-preference for feeding tests leaded to the conclusion that this type of resistance is present in ZC and Mp707. These

  10. 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)

    Sundaram, A.; Sundaram, K.M.S.

    1996-01-01

    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 (DT 50 , 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, RF 50 [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 RF 50 value was high (5.2 mm) for the small rain droplets

  11. Influence of cover crops on insect pests and predators in conservation tillage cotton.

    Science.gov (United States)

    Tillman, Glynn; Schomberg, Harry; Phatak, Sharad; Mullinix, Benjamin; Lachnicht, Sharon; Timper, Patricia; Olson, Dawn

    2004-08-01

    In fall 2000, an on-farm sustainable agricultural research project was established for cotton, Gossypium hirsutum L., in Tift County, Georgia. The objective of our 2-yr research project was to determine the impact of several cover crops on pest and predator insects in cotton. The five cover crop treatments included 1) cereal rye, Secale cereale L., a standard grass cover crop; 2) crimson clover, Trifolium incarnatum L., a standard legume cover crop; 3) a legume mixture of balansa clover, Trifolium michelianum Savi; crimson clover; and hairy vetch, Vicia villosa Roth; 4) a legume mixture + rye combination; and 5) no cover crop in conventionally tilled fields. Three main groups or species of pests were collected in cover crops and cotton: 1) the heliothines Heliothis virescens (F.) and Helicoverpa zea (Boddie); 2) the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois); and 3) stink bugs. The main stink bugs collected were the southern green stink bug, Nezara viridula (L.); the brown stink bug, Euschistus servus (Say); and the green stink bug, Acrosternum hilare (Say). Cotton aphids, Aphis gossypii Glover, were collected only on cotton. For both years of the study, the heliothines were the only pests that exceeded their economic threshold in cotton, and the number of times this threshold was exceeded in cotton was higher in control cotton than in crimson clover and rye cotton. Heliothine predators and aphidophagous lady beetles occurred in cover crops and cotton during both years of the experiment. Geocoris punctipes (Say), Orius insidiosus (Say), and red imported fire ant, Solenopsis invicta Buren were relatively the most abundant heliothine predators observed. Lady beetles included the convergent lady beetle, Hippodamia convergens Guérin-Méneville; the sevenspotted lady beetle, Coccinella septempunctata L.; spotted lady beetle, Coleomegilla maculata (DeGeer); and the multicolored Asian lady beetle, Harmonia axyridis (Pallas). Density of G. punctipes was

  12. Effect of Different Diets of Flour Moth on its Parasitoid Wasp Fitness, Trichogramma brassicae (Hym.:Trichogrammatidae

    Directory of Open Access Journals (Sweden)

    Paria Soltaninejad

    2017-03-01

    Full Text Available Introduction: Parasitoid wasp, Trichogramma brassicae (Bezdenko (Hym.: Trichogrammatidae has excellent position in mass production technology, scope of application, wide geographical distribution and unmatched talent to adapt to different climatic conditions that can be easily reared on Mediterranean flour moth (MFM, Ephestia kuehniella Zeller (Lep.: Pyralidae. The parasitoid use is in order to control Chilo suppressalis (Walker (Lep.: Pyralidae, Helicoverpa armigera (Lep.: Noctuidae, Ostrinia nubilalis (Hübner (Lep.: Pyralidae, Ectomyelois ceratoniae (Zeller (Lep.: Phycitidae and Cydia pomonella (Lep.: Tortricidae (38. The studies have been shown that the quantity and quality of the host diet affect growth period, size of adults, adult longevity, fecundity and sex ratio of the parasitoid. The objective of current research was to evaluate the effect of four different MFM diets on the fitness of second and forth generations of the parasitoid wasp, T. brassicae. Materials and Methods: The four diets ((I wheat flour, wheat bran, corn flour, bread yeast and glycerin; (II wheat flour, wheat bran, barley flour, bread yeast and glycerin; (III barley flour, bread yeast and glycerin and (IV wheat flour, barley flour and corn flour were sterilized at 51 °C for 24 hours. After cooling at ambient temperature, the diets were contaminated with the eggs of MFM and then were maintained at 25±1° C, 60±5 % RH and a photoperiod of 14 L: 10 D. The MFM adults emerged after 35 to 40 days and their eggs were collected daily to use for investigation of the parasitoid biology. For rearing the parasitoid wasps on the MFM eggs obtained from each diet, some cards containing the parasitoid pre-pupae were put inside cages (25 × 25 × 25 cm and reared for one generation. The adults were fed honey (20% for one day and then were provided with one-day-old sterile MFM eggs. To prevent egg hatching and sterile them, they were kept at 15°C for four h. The tests were