WorldWideScience

Sample records for lepidoptera-specific bt corn

  1. Delaying corn rootworm resistance to Bt corn.

    Science.gov (United States)

    Tabashnik, Bruce E; Gould, Fred

    2012-06-01

    Transgenic crops producing Bacillus thuringiensis (Bt) toxins for insect control have been successful, but their efficacy is reduced when pests evolve resistance. To delay pest resistance to Bt crops, the U.S. Environmental Protection Agency (EPA) has required refuges of host plants that do not produce Bt toxins to promote survival of susceptible pests. Such refuges are expected to be most effective if the Bt plants deliver a dose of toxin high enough to kill nearly all hybrid progeny produced by matings between resistant and susceptible pests. In 2003, the EPA first registered corn, Zea mays L., producing a Bt toxin (Cry3Bb1) that kills western corn rootworm, Diabrotica virgifera virgifera LeConte, one of the most economically important crop pests in the United States. The EPA requires minimum refuges of 20% for Cry3Bb1 corn and 5% for corn producing two Bt toxins active against corn rootworms. We conclude that the current refuge requirements are not adequate, because Bt corn hybrids active against corn rootworms do not meet the high-dose standard, and western corn rootworm has rapidly evolved resistance to Cry3Bb1 corn in the laboratory, greenhouse, and field. Accordingly, we recommend increasing the minimum refuge for Bt corn targeting corn rootworms to 50% for plants producing one toxin active against these pests and to 20% for plants producing two toxins active against these pests. Increasing the minimum refuge percentage can help to delay pest resistance, encourage integrated pest management, and promote more sustainable crop protection.

  2. Risk and the Value of Bt Corn

    OpenAIRE

    Terrance M. Hurley; Paul D. Mitchell; Marlin E. Rice

    2004-01-01

    A conceptual model is developed to evaluate the effect of Bt corn on risk. Results highlight the importance of distinguishing between marginal and aggregate risk effects and demonstrate that the effect of Bt corn on risk depends crucially on the price paid for the technology. Empirical results show that, depending on the price, Bt corn can be marginally risk increasing or decreasing and can either increase or decrease corn acreage. Also, depending on the price, Bt corn can provide a risk bene...

  3. WHAT IS THE VALUE OF BT CORN?

    OpenAIRE

    Hurley, Terrance M.; Mitchell, Paul D.; Rice, Marlin E.

    2001-01-01

    A common perception is that the value of Bt corn arises from two components-Bt corn increases expected profit and reduces profit variability. This perception encourages farmers and the policy makers to add a risk benefit to estimates of the value of Bt corn to account for the variability reduction. However, a conceptual model generates a useful decomposition of the value of Bt corn and a condition determining the impact of Bt corn on profit variability. An empirical model finds that Bt corn i...

  4. Does Bt Corn Really Produce Tougher Residues

    Science.gov (United States)

    Bt corn hybrids produce insecticidal proteins that are derived from a bacterium, Bacillus thuringiensis. There have been concerns that Bt corn hybrids produce residues that are relatively resistant to decomposition. We conducted four experiments that examined the decomposition of corn residues und...

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

    Science.gov (United States)

    Chilcutt, Charles F

    2006-06-01

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

  6. THE ECONOMICS OF REFUGE DESIGN FOR BT CORN

    OpenAIRE

    Hyde, Jeffrey; Martin, Marshall A.; Preckel, Paul V.; Dobbins, Craig L.; Edwards, C. Richard

    1999-01-01

    Planting Bt corn on large areas may lead to European corn borer (ECB) resistance to Bt. Scientists recommend planting a non-Bt corn refuge as part of a resistance management strategy. Different refuge configurations may impact farm profits differently. This paper analyzes the economics of alternative refuge configurations in Indiana.

  7. Field-based assessment of resistance to Bt Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae)

    Science.gov (United States)

    Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a serious pest of corn and is managed with Bt corn that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt). Beginning in 2009, severe injury to Bt corn producing Cry3Bb1 was observed in some cornfields ...

  8. Dispersal behavior of neonate European corn borer (Lepidoptera: Crambidae) on Bt corn.

    Science.gov (United States)

    Razze, J M; Mason, C E

    2012-08-01

    European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), has historically been a significant economically important insect pest of corn (Zea mays L.) in the United States and Canada. The development in the 1990s of genetically modified corn expressing genes derived from Bacillus thuringiensis (Bt) that encodes insecticidal crystalline (Cry) proteins has proven to be effective in controlling this insect as well as other corn pests. The purpose of this study was to assess the movement and dispersal behavior of neonate European corn borer on Bt corn. We examined differences in neonate European corn borer dispersal behavior for the first 4 h after eclosion in the field among a stacked pyramid (Cry1F X Cry1Ab X Cry34/35Ab1) Bt corn, a Cry1F Bt corn, and a non-Bt sweet corn; and in the laboratory among a Bt corn hybrid containing Cry1F, a hybrid containing Cry1Ab, a pyramid combining these two hybrids (Cry1F X Cry1Ab), and a non-Bt near isoline corn. In field experiments, we found that dispersal was significantly higher on Bt corn compared with sweet corn. In laboratory experiments, dispersal was significantly higher on Cry1Ab Bt corn and Cry1F X Cry1Ab Bt corn than on non-Bt near isoline corn. Results indicated that neonate dispersal may be significantly greater in Bt cornfields compared with non-Bt cornfields. The findings on dispersal behavior in this study will be useful in evaluating the efficacy of a blended seed refuge system for managing European corn borer resistance in Bt corn.

  9. Dispersal and movement behavior of neonate European corn borer (Lepidoptera: Crambidae) on non-Bt and transgenic Bt corn.

    Science.gov (United States)

    Goldstein, Jessica A; Mason, Charles E; Pesek, John

    2010-04-01

    Neonate movement and dispersal behavior of the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), were investigated under controlled conditions on Bacillus thuringiensis (Bt) and non-Bt corn, Zea mays L., to assess plant abandonment, dispersal from their natal plant, and silking behavior after Bt and non-Bt preexposure. With continuous airflow, neonates on a Bt corn plant for 24 h abandoned that plant 1.78 times more frequently than neonates on a non-Bt corn plant. Indirect evidence indicated that at least one third of the neonates were capable of ballooning within 24 h. In the greenhouse, some neonates were recovered after 24 h from plants 76 and 152 cm away that likely ballooned from their natal plant. After 1 h of preexposure on a Bt corn leaf, neonates placed on a new corn leaf and observed for 10 min began silking off of a new Bt leaf significantly sooner than a new non-Bt leaf. Results suggest that neonates are unable to detect Bt in the corn within 10 min but that they can detect it within the first hour.

  10. FARMER DEMAND FOR CORN ROOTWORM BT CORN: DO INSECT RESISTANCE MANAGEMENT GUIDELINES MATTER?

    OpenAIRE

    Langrock, Ines; Hurley, Terrance M.; Ostlie, Kenneth

    2003-01-01

    Farmer adoption of Bt corn and compliance with insect resistance management (IRM) regulations will influence the success of these regulations. The purpose of this paper is to use farmer survey data to estimate the demand for new corn rootworm Bt corn and the cost of complying with proposed IRM regulations.

  11. Screening for corn rootworm (Coleoptera: Chrysomelidae) resistance to transgenic Bt corn in North Dakota

    Science.gov (United States)

    Western (WCR), Diabrotica virgifera virgifera LeConte, and northern corn rootworms (NCR), D. barberi Smith & Lawrence, are major economic pests of corn in much of the U.S. Corn Belt. Western corn rootworm resistance to transgenic corn expressing Bt (Bacillus thuringiensis) endotoxins has been confi...

  12. Effects of Pyramided Bt Corn and Blended Refuges on Western Corn Rootworm and Northern Corn Rootworm (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Keweshan, Ryan S; Head, Graham P; Gassmann, Aaron J

    2015-04-01

    The western corn rootworm, Diabrotica virgifera virgifera LeConte, and the northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), are major pests of corn (Zea mays L). Several transgenic corn events producing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) kill corn rootworm larvae and reduce injury to corn roots. However, planting of Bt corn imposes selection on rootworm populations to evolve Bt resistance. The refuge strategy and pyramiding of multiple Bt toxins can delay resistance to Bt crops. In this study, we assessed the impact of four treatments--1) non-Bt corn, 2) Cry3Bb1 corn, 3) corn pyramided with Cry3Bb1 and Cry34/35Ab1, and 4) pyramided corn with a blended refuge--on survival, time of adult emergence, and size of western and northern corn rootworm. All treatments with Bt corn led to significant reductions in the number of adults that emerged per plot. However, at one location, we identified Cry3Bb1-resistant western corn rootworm. In some cases Bt treatments reduced size of adults and delayed time of adult emergence, with effects most pronounced for pyramided corn. For both species, the number of adults that emerged from pyramided corn with a blended refuge was significantly lower than expected, based solely on emergence from pure stands of pyramided corn and non-Bt corn. The results of this study indicate that pyramided corn with a blended refuge substantially reduces survival of both western and northern corn rootworm, and as such, should be a useful tool within the context of a broader integrated pest management strategy. © 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.

  13. ESTIMATING THE VALUE OF BT CORN: A MULTI-STATE COMPARISON

    OpenAIRE

    Hyde, Jeffrey; Martin, Marshall A.; Preckel, Paul V.; Edwards, C. Richard; Dobbins, Craig L.

    2000-01-01

    Bt corn offers a powerful tool to control European corn borers and some other pests. Because pest infestations and farming practices differ across the Corn Belt, economic benefits also differ. This research estimates the value of Bt corn across the Corn Belt. Results identify areas where Bt adoption is economically justified.

  14. Resistance to Bt corn by western corn rootworm (Coleoptera: Chrysomelidae) in the U.S. corn belt

    Science.gov (United States)

    Transgenic Bt corn hybrids that produce insecticidal proteins from the bacterium Bacillus thuringiensis Berliner have become the standard insect management tactic across the United States Corn Belt. Widespread planting of Bt corn creates intense selection pressure for target insects to develop resis...

  15. Cross-resistance to purified Bt proteins, Bt corn and Bt cotton in a Cry2Ab2-corn resistant strain of Spodoptera frugiperda.

    Science.gov (United States)

    Yang, Fei; Kerns, David L; Head, Graham P; Price, Paula; Huang, Fangneng

    2017-12-01

    Gene-pyramiding by combining two or more dissimilar Bacillus thuringiensis (Bt) proteins into a crop has been used to delay insect resistance. The durability of gene-pyramiding can be reduced by cross-resistance. Fall armyworm, Spodoptera frugiperda, is a major target pest of the Cry2Ab2 protein used in pyramided Bt corn and cotton. Here, we provide the first experimental evaluation of cross-resistance in S. frugiperda selected with Cry2Ab2 corn to multiple Bt sources including purified Bt proteins, Bt corn and Bt cotton. Concentration - response bioassays showed that resistance ratios for Cry2Ab2-resistant (RR) relative to Cry2Ab2-susceptible (SS) S. frugiperda were -1.4 for Cry1F, 1.2 for Cry1A.105, >26.7 for Cry2Ab2, >10.0 for Cry2Ae and -1.1 for Vip3A. Larvae of Cry2Ab2-heterozygous (RS), SS and RR S. frugiperda were all susceptible to Bt corn and Bt cotton containing Cry1 (Cry1F or Cry1A.105) and/or Vip3A proteins. Pyramided Bt cotton containing Cry1Ac + Cry2Ab2 or Cry1Ab + Cry2Ae were also effective against SS and RS, but not RR. These findings suggest that Cry2Ab2-corn-selected S. frugiperda is not cross-resistant to Cry1F, Cry1A.105 or Vip3A protein, or corn and cotton plants containing these Bt proteins, but it can cause strong cross-resistance to Cry2Ae and Bt crops expressing similar Bt proteins. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  16. ECONOMIC EVALUATION OF BT CORN REFUGE INSURANCE

    OpenAIRE

    Mitchell, Paul D.; Hurley, Terrance M.; Hellmich, Richard L.

    2000-01-01

    The EPA has imposed mandatory refuge requirements for Bt crops to prolong the efficacy of Bt. Growers have no economic incentive to plant the required refuge because refuge crops are on average less productive and more risky. This paper evaluates refuge insurance--insurance that pays indemnities for yield losses on refuge due to insect damage--as a tool to increase grower compliance incentives. We determine actuarially fair insurance premiums, then evaluate the feasibility of private provisio...

  17. Bt Sweet Corn: What Is It and Why Should We Use It?

    OpenAIRE

    Barlow, Vonny M.; Kuhar, Thomas Patrick, 1969-; Speese, John

    2009-01-01

    This publication reviews Transgenic Bt sweet corn hybrids which are a genetically modified organism (GMO) that are the result of combining commercially available sweet corn varieties with genes from a naturally occurring soil bacterium called Bacillus thuringiensis Berliner or Bt.

  18. Host Recognition Responses of Western (Family: Chrysomelidae) Corn Rootworm Larvae to RNA Interference and Bt Corn

    OpenAIRE

    Zukoff, Sarah N.; Zukoff, Anthony L.

    2017-01-01

    Western corn rootworm Diabrotica virgifera virgifera LeConte is an important pest of corn whose larvae exhibit particular quantifiable patterns of locomotion after exposure to, and removal from, host roots and nonhost roots. Using EthoVision software, the behavior and locomotion of the western corn rootworm larvae was analyzed to determine the level of host recognition to germinated roots of differing corn hybrids containing either rootworm targeted Bt genes, RNA interference (RNAi) technolog...

  19. Adaptation by western corn rootworm to Bt corn: characterizing inheritance, fitness costs, and feeding preference

    Science.gov (United States)

    In this study, we used a laboratory-selected, Bt-resistant strain of western corn rootworm, Diabrotica virgifera virgifera Le Conte, to characterize inheritance of resistance, feeding behavior, and fitness costs associated with resistance to maize producing the Bacillus thuringiensis (Bt) toxin Cry3...

  20. Field Studies to Evaluate Potential Differences between Bt and non-Bt Corn Residue

    Science.gov (United States)

    Some reports suggest that the genetically-modified Bt corn residue may have higher lignin content and that the residue may be more resistant to decomposition. If true, then there are implications for both farming practices, e.g., tillage and planting, as well as global carbon budgets. We conducted ...

  1. [Change of Bt protein in soil after growing Bt corns and returning corn straws to soil and its effects on soil nutrients].

    Science.gov (United States)

    Zeng, Ping; Feng, Yuan-Jiao; Zhang, Wan-Chun; Zhang, Yan-Fei; Dong, Wen-Chao; Wang, Jian-Wu

    2014-07-01

    The spatiotemporal dynamics of Bt protein in soil and the change of soil nutrients in rhizosphere soil, root surface soil and soils at 0-20, 20-40 and 40-60 cm were measured in greenhouse experiments. Two Bt corns, 5422Bt1 and 5422CBCL, and their near isogenic non-Bt variety 5422 were grown for 90 days and the crop residues were retained to soil. Results showed that 1.59 and 2.78 ng x g(-1) Bt protein were detected in the rhizosphere soil with Bt corns 5422Bt1 and 5422CBCL immediately after harvest. However, there were only trace amounts of Bt protein (Bt corn treatments after 30, 60 and 90 days. When corn residues returned to soil, Bt protein declined rapidly within 3 days and only trace amounts of Bt protein were measured after 7 days. There were no sig- nificant differences in organic matter, available nutrient (alkaline hydrolytic N, available P, available K) or total nutrient (total N, total P, total K) in root surface soils and soils at 0-20 cm, 20-40 cm and 40-60 cm among the Bt and non-Bt corns after 90 days. Sixty days after returning crop residues of 5422Btl to soil, the contents of organic matter and total N increased and the content of available K reduced significantly in the 0-20 cm soil depth. There were no significant differences in any other parameter at the 0-20 cm depth, neither for any parameter in the 20-40 cm and 40-60 cm soil depths compared to those in the non-Bt corn 5422 treatment. There were no significant differences in soil nutrient contents in Bt corn 5422CBCL treatment compared to those in non-Bt corn 5422 treatment except that available phosphorus content was reduced in root surface soils, and total P content increased at the 0-20 cm soil depth after 90 days. When crop residues of Bt corn 5422 CBCL were returned to soil, only available P content in the 0-20 cm soil layer was evidently higher compared to the soil receiving crop residues of non-Bt corn 5422. Results suggested that Bt protein released from root and crop residues of Bt

  2. Effects of MON810 Bt field corn on adult emergence of Helicoverpa zea (Lepidoptera: Noctuidae).

    Science.gov (United States)

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

    2003-06-01

    A 3-yr study (1996-1998) was conducted to evaluate the effects of MON810 Bt corn on Helicoverpa zea (Boddie) emergence and to determine whether delayed larval development as a result of Bt intoxication results in higher levels of diapause induction and pupal mortality. In the 1997 study, there was no difference in prepupal mortality between corn types, although significantly more prepupae from Bt plots than from non-Bt plots died in emergence buckets before constructing pupal chambers in 1998. In all years, significantly fewer moths emerged from prepupae collected from Bt plots, suggesting that effects of the expressed Cry1Ab extended to the prepupal and pupal stages. Late plantings of corn showed the greatest reductions in moth emergence from Bt corn because environmental conditions were more conducive to trigger diapause at the time H. zea was developing in these plantings. This was supported by a significantly greater proportion of diapausing pupae remaining in the ground in the late plantings of both Bt and non-Bt corn. For April and early May plantings, larval feeding on Bt corn delayed the time to pupation, although there was no significant difference in moth emergence between corn types for those larvae that successfully pupated. Although Bt expression had less impact on the proportion of moths emerging, the actual number of moths emerging from Bt corn was significantly reduced because fewer larvae reached pupation. Delays in adult emergence, along with significant reductions in adult emergence from MON810 Bt corn, should reduce the rates of colonization in soybean and other late host crops but may also result in asynchrony of mating between individuals emerging from Bt and non-Bt corn. This, in turn, may contribute to the evolution of resistance to Bt corn.

  3. Understanding successful resistance management: the European corn borer and Bt corn in the United States.

    Science.gov (United States)

    Siegfried, Blair D; Hellmich, Richard L

    2012-01-01

    The European corn borer, Ostrinia nubilalis Hübner (Lepidoptera: Crambidae) has been a major pest of corn and other crops in North America since its accidental introduction nearly a hundred years ago. Wide adoption of transgenic corn hybrids that express toxins from Bacillus thuringiensis, referred to as Bt corn, has suppressed corn borer populations and reduced the pest status of this insect in parts of the Corn Belt. Continued suppression of this pest, however, will depend on managing potential resistance to Bt corn, currently through the high-dose refuge (HDR) strategy. In this review, we describe what has been learned with regard to O. nubilalis resistance to Bt toxins either through laboratory selection experiments or isolation of resistance from field populations. We also describe the essential components of the HDR strategy as they relate to O. nubilalis biology and ecology. Additionally, recent developments in insect resistance management (IRM) specific to O. nubilalis that may affect the continued sustainability of this technology are considered.

  4. Genetic markers for western corn rootworm resistance to Bt toxin.

    Science.gov (United States)

    Flagel, Lex E; Swarup, Shilpa; Chen, Mao; Bauer, Christopher; Wanjugi, Humphrey; Carroll, Matthew; Hill, Patrick; Tuscan, Meghan; Bansal, Raman; Flannagan, Ronald; Clark, Thomas L; Michel, Andrew P; Head, Graham P; Goldman, Barry S

    2015-01-07

    Western corn rootworm (WCR) is a major maize (Zea mays L.) pest leading to annual economic losses of more than 1 billion dollars in the United States. Transgenic maize expressing insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely used for the management of WCR. However, cultivation of Bt-expressing maize places intense selection pressure on pest populations to evolve resistance. Instances of resistance to Bt toxins have been reported in WCR. Developing genetic markers for resistance will help in characterizing the extent of existing issues, predicting where future field failures may occur, improving insect resistance management strategies, and in designing and sustainably implementing forthcoming WCR control products. Here, we discover and validate genetic markers in WCR that are associated with resistance to the Cry3Bb1 Bt toxin. A field-derived WCR population known to be resistant to the Cry3Bb1 Bt toxin was used to generate a genetic map and to identify a genomic region associated with Cry3Bb1 resistance. Our results indicate that resistance is inherited in a nearly recessive manner and associated with a single autosomal linkage group. Markers tightly linked with resistance were validated using WCR populations collected from Cry3Bb1 maize fields showing significant WCR damage from across the US Corn Belt. Two markers were found to be correlated with both diet (R2 = 0.14) and plant (R2 = 0.23) bioassays for resistance. These results will assist in assessing resistance risk for different WCR populations, and can be used to improve insect resistance management strategies. Copyright © 2015 Flagel et al.

  5. Modeling evolution of resistance of sugarcane borer (Lepidoptera: Crambidae) to transgenic Bt corn.

    Science.gov (United States)

    Kang, J; Huang, F; Onstad, D W

    2014-08-01

    Diatraea saccharalis (F.) (Lepidoptera: Crambidae) is a target pest of transgenic corn expressing Bacillus thuringiensis (Bt) protein, and the first evidence of resistance by D. saccharalis to Cry1Ab corn was detected in a field population in northeast Louisiana in 2004. We used a model of population dynamics and genetics of D. saccharalis to 1) study the effect of interfield dispersal, the first date that larvae enter diapause for overwintering, toxin mortality, the proportion of non-Bt corn in the corn patch, and the area of a crop patch on Bt resistance evolution; and 2) to identify gaps in empirical knowledge for managing D. saccharalis resistance to Bt corn. Increasing, the proportion of corn refuge did not always improve the durability of Bt corn if the landscape also contained sugarcane, sorghum, or rice. In the landscape, which consisted of 90% corn area, 5% sorghum area, and 5% rice area, the durability of single-protein Bt corn was 40 yr when the proportion of corn refuge was 0.2 but 16 yr when the proportion of corn refuge was 0.5. The Bt resistance evolution was sensitive to a change (from Julian date 260 to 272) in the first date larvae enter diapause for overwintering and moth movement. In the landscapes with Bt corn, non-Bt corn, sugarcane, sorghum, and rice, the evolution of Bt resistance accelerated when larvae entered diapause for overwintering early. Intermediate rates of moth movement delayed evolution of resistance more than either extremely low or high rates. This study suggested that heterogeneity in the agrolandscapes may complicate the strategy for managing Bt resistance in D. saccharalis, and designing a Bt resistance management strategy for D. saccharalis is challenging because of a lack of empirical data about overwintering and moth movement.

  6. Sustainability of insect resistance management strategies for transgenic Bt corn.

    Science.gov (United States)

    Glaser, John A; Matten, Sharlene R

    2003-12-01

    Increasing interest in the responsible management of technology in the industrial and agricultural sectors of the economy has been met thorough the development of broadly applicable tools to assess the "sustainability" of new technologies. An arena ripe for application of such analysis is the deployment of transgenic crops. The new transgenic pesticidal or plant-incorporated protectant (PIP) crops have seen widespread application in the United States based on the features of higher yield, lower applications of insecticides, and control of mycotoxin content. However, open rejection of these new crops in Europe and in other countries has been a surprising message and has limited their worldwide acceptance. The US Environmental Protection Agency's (USEPA) Office of Pesticide Programs (OPP) has worked on the development and analysis of insect resistance management (IRM) strategies and has mandated specific IRM requirements for Bacillus thuringiensis (Bt) crops since 1995 under the Food, Fungicide, Insecticide, and Rodenticide Act. Improvement of data quality and sustainability of IRM strategies have been targeted in an ongoing partnership between the USEPA Office of Research and Development and the Office of Pesticide Programs that will further enhance the agency's ability to develop sustainable insect resistance management strategies for transgenic field corn (Bt corn) producing B. thuringiensis (Bt) insecticidal proteins.

  7. Cross-pollination of nontransgenic corn ears with transgenic Bt corn: efficacy against lepidopteran pests and implications for resistance management.

    Science.gov (United States)

    Burkness, E C; O'Rourke, P K; Hutchison, W D

    2011-10-01

    The efficacy of nontransgenic sweet corn, Zea mays L., hybrids cross-pollinated by Bacillus thuringiensis (Bt) sweet corn hybrids expressing Cry1Ab toxin was evaluated in both field and laboratory studies in Minnesota in 2000. Non-Bt and Bt hybrids (maternal plants) were cross-pollinated with pollen from both non-Bt and Bt hybrids (paternal plants) to create four crosses. Subsequent crosses were evaluated for efficacy in the field against European corn borer, Ostrinia nubilalis (Hübner), and corn earworm, Helicoverpa zea (Boddie), and in laboratory bioassays against O. nubilalis. Field studies indicated that crosses with maternal Bt plants led to low levels of survival for both O. nubilalis and H. zea compared with the non-Bt x non-Bt cross. However, the cross between non-Bt ears and Bt pollen led to survival rates of 43 and 63% for O. nubilalis and H. zea larvae, respectively. This intermediate level of survival also was reflected in the number of kernels damaged. Laboratory bioassays for O. nubilalis, further confirmed field results with larval survival on kernels from the cross between non-Bt ears and Bt pollen reaching 60% compared with non-Bt crossed with non-Bt. These results suggest that non-Bt refuge plants, when planted in proximity to Bt plants, and cross-pollinated, can result in sublethal exposure of O. nubilalis and H. zea larvae to Bt and may undermine the high-dose/refuge resistance management strategy for corn hybrids expressing Cry1Ab.

  8. Impact of corn earworm injury on yield of transgenic corn producing Bt toxins in the Carolinas.

    Science.gov (United States)

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

    2014-06-01

    Transgenic corn, Zea mays L., hybrids expressing insecticidal Cry proteins from Bacillus thuringiensis (Bt) and insecticide applications to suppress injury from Helicoverpa zea (Boddie) were evaluated in Florence, SC, and in Plymouth, NC, in 2012 and 2013. Based on kernel area injured, insecticide applications (chlorantraniliprole) every 3-4 d from R1 until H. zea had cycled out of corn reduced injury by 80-93% in Florence and 94-95% in Plymouth. Despite intensive applications of insecticide (13-18 per trial), limited injury still occurred in all treated plots in 2012, except in DKC 68-03 (Genuity VT Double PRO), based on kernels injured (both locations) and proportion of injured ears (Florence only). In 2013, ear injury was low in Plymouth, with no kernel injury in any insecticide-treated plots, except P1498R (non-Bt) and P1498YHR (Optimum Intrasect). Injury in Florence in 2013 did not occur in treated plots of DKC 68-04 (non-Bt), DKC 68-03 (Genuity VT Double PRO), and N785-3111 (Agrisure Viptera). Yields were not significantly affected by insecticide treatment and were not statistically different among near-isolines with and without Bt traits. Yields were not significantly associated with kernel injury based on regression analyses. The value of using Bt corn hybrids to manage H. zea is discussed.

  9. The effects of bt corn on rusty crayfish (Orconectes rusticus) growth and survival.

    Science.gov (United States)

    Linn, Matthew D; Moore, Paul A

    2014-10-01

    Bt crops are one of the most commonly used genetically modified crops worldwide. Bt crops contain a gene that is derived from the bacteria Bacillus thuringiensis, which produces the Cry1Ab toxin. Bt corn that contains the Cry1Ab toxin is used throughout the Midwest United States to control crop pests such as the European corn borer (Ostrinia nubilalis). Headwater streams in regions known for intensive agriculture receive Bt corn detritus after the fall harvest, which is then consumed by a diverse community of stream invertebrates. The rusty crayfish (Orconectes rusticus) is a common invertebrate detritivore in these headwater streams. Both isogenic and Bt corn were grown under the controlled environmental conditions of a greenhouse and, after senescence, were tested for nutritional equality. Rusty crayfish were exposed to one of several detrital treatments composed of Bt corn, Bt corn plus American sycamore (Platanus occidentalis), isogenic corn alone, isogenic corn plus P. occidentalis, or P. occidentalis alone for 8 weeks. Both strains of corn were grown under the controlled environmental conditions in a greenhouse and were tested for nutritional equality after senescence. Crayfish were housed in live streams with a water temperature of 12.8 °C and a 12:12 h light-to-dark photoperiod. Survival and growth of animals within each experimental treatment were monitored each week. After 8 weeks of exposure, there was no statistically significant difference in growth between crayfish in Bt and isogenic treatments. However, survivorship was 31 % lower in the Bt treatment compared with the isogenic treatment. These results suggest that the Bt corn and isogenic corn were of equivalent nutritional value but that Bt corn does have a toxic effect on rusty crayfish during long-term exposure.

  10. The cultivation of Bt corn producing Cry1Ac toxins does not adversely affect non-target arthropods.

    Science.gov (United States)

    Guo, Yanyan; Feng, Yanjie; Ge, Yang; Tetreau, Guillaume; Chen, Xiaowen; Dong, Xuehui; Shi, Wangpeng

    2014-01-01

    Transgenic corn producing Cry1Ac toxins from Bacillus thuringiensis (Bt) provides effective control of Asian corn borer, Ostrinia furnacalis (Guenée), and thus reduces insecticide applications. However, whether Bt corn exerts undesirable effects on non-target arthropods (NTAs) is still controversial. We conducted a 2-yr study in Shangzhuang Agricultural Experiment Station to assess the potential impact of Bt corn on field population density, biodiversity, community composition and structure of NTAs. On each sampling date, the total abundance, Shannon's diversity index, Pielou's evenness index and Simpson's diversity index were not significantly affected by Bt corn as compared to non-Bt corn. The "sampling dates" had a significant effect on these indices, but no clear tendencies related to "Bt corn" or "sampling dates X corn variety" interaction were recorded. Principal response curve analysis of variance indicated that Bt corn did not alter the distribution of NTAs communities. Bray-Curtis dissimilarity and distance analysis showed that Cry1Ac toxin exposure did not increase community dissimilarities between Bt and non-Bt corn plots and that the evolution of non-target arthropod community was similar on the two corn varieties. The cultivation of Bt corn failed to show any detrimental evidence on the density of non-target herbivores, predators and parasitoids. The composition of herbivores, predators and parasitoids was identical in Bt and non-Bt corn plots. Taken together, results from the present work support that Bt corn producing Cry1Ac toxins does not adversely affect NTAs.

  11. Dominant inheritance of field-evolved resistance to Bt corn in Busseolafusca.

    Directory of Open Access Journals (Sweden)

    Pascal Campagne

    Full Text Available Transgenic crops expressing Bacillus thuringiensis (Bt toxins have been adopted worldwide, notably in developing countries. In spite of their success in controlling target pests while allowing a substantial reduction of insecticide use, the sustainable control of these pest populations is threatened by the evolution of resistance. The implementation of the "high dose/refuge" strategy for managing insect resistance in transgenic crops aims at delaying the evolution of resistance to Bt crops in pest populations by promoting survival of susceptible insects. However, a crucial condition for the "high dose/refuge" strategy to be efficient is that the inheritance of resistance should be functionally recessive. Busseolafusca developed high levels of resistance to the Bt toxin Cry 1Ab expressed in Bt corn in South Africa. To test whether the inheritance of B. fusca resistance to the Bt toxin could be considered recessive we performed controlled crosses with this pest and evaluated its survival on Bt and non-Bt corn. Results show that resistance of B. fusca to Bt corn is dominant, which refutes the hypothesis of recessive inheritance. Survival on Bt corn was not lower than on non-Bt corn for both resistant larvae and the F1 progeny from resistant × susceptible parents. Hence, resistance management strategies of B. fusca to Bt corn must address non-recessive resistance.

  12. Dominant inheritance of field-evolved resistance to Bt corn in Busseolafusca.

    Science.gov (United States)

    Campagne, Pascal; Kruger, Marlene; Pasquet, Rémy; Le Ru, Bruno; Van den Berg, Johnnie

    2013-01-01

    Transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been adopted worldwide, notably in developing countries. In spite of their success in controlling target pests while allowing a substantial reduction of insecticide use, the sustainable control of these pest populations is threatened by the evolution of resistance. The implementation of the "high dose/refuge" strategy for managing insect resistance in transgenic crops aims at delaying the evolution of resistance to Bt crops in pest populations by promoting survival of susceptible insects. However, a crucial condition for the "high dose/refuge" strategy to be efficient is that the inheritance of resistance should be functionally recessive. Busseolafusca developed high levels of resistance to the Bt toxin Cry 1Ab expressed in Bt corn in South Africa. To test whether the inheritance of B. fusca resistance to the Bt toxin could be considered recessive we performed controlled crosses with this pest and evaluated its survival on Bt and non-Bt corn. Results show that resistance of B. fusca to Bt corn is dominant, which refutes the hypothesis of recessive inheritance. Survival on Bt corn was not lower than on non-Bt corn for both resistant larvae and the F1 progeny from resistant × susceptible parents. Hence, resistance management strategies of B. fusca to Bt corn must address non-recessive resistance.

  13. Host Recognition Responses of Western (Family: Chrysomelidae) Corn Rootworm Larvae to RNA Interference and Bt Corn.

    Science.gov (United States)

    Zukoff, Sarah N; Zukoff, Anthony L

    2017-01-01

    Western corn rootworm Diabrotica virgifera virgifera LeConte is an important pest of corn whose larvae exhibit particular quantifiable patterns of locomotion after exposure to, and removal from, host roots and nonhost roots. Using EthoVision software, the behavior and locomotion of the western corn rootworm larvae was analyzed to determine the level of host recognition to germinated roots of differing corn hybrids containing either rootworm targeted Bt genes, RNA interference (RNAi) technology, the stack of both Bt and RNAi, or the isoline of these. The behavior of the rootworm larvae indicated a significant host preference response to all corn hybrids (with or without insecticidal traits) compared to the filter paper and oat roots. A weaker host response to the RNAi corn roots was observed in the susceptible larvae when compared to the resistant larvae, but not for the Bt + RNAi vector stack. Additionally, the resistant larvae demonstrated a weaker host response to the isoline corn roots when compared to the susceptible larvae. Although weaker, these host responses were significantly different from those observed in the negative controls, indicating that all hybrids tested do contain the contact cues necessary to elicit a host preference response by both Cry3Bb1-resistant and Cry3Bb1-susceptible larvae that would work to hinder resistance development in refuge in a bag fields. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

  14. ECONOMIC VIABILITY OF BT-CORN IN THE U.S.

    OpenAIRE

    Kim, Hong Jin; Konyar, Kazim; Sargent, Keith

    2002-01-01

    Bt-corn, a genetically engineered insect resistant variety, has been adopted by almost one-quarter of all corn farmers, resulting in economic impacts on both conventional corn growers and Bt-corn growers. we estimate changes in profits for both types of farmers with different levels of seed premiums, yield increases and adoption rates. We find that Bt-corn growers will see their profits decline when the adoption rate and seed premium are high, if they are not offset by higher yields. Conventi...

  15. Modeling a western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), maturation delay and resistance evolution in Bt corn.

    Science.gov (United States)

    Kang, Jung Koo; Krupke, Christian H; Murphy, Alexzandra F; Spencer, Joseph L; Gray, Michael E; Onstad, David W

    2014-06-01

    Emergence delay and female-skewed sex ratios among adults of Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) from Bt corn have been reported in field studies. The authors used a simulation model to study the effect of a maturation delay and a female-skewed sex ratio for D. v. virgifera emerging from Bt corn on the evolution of Bt resistance. The effect of skewed toxin mortality in one sex on evolution of Bt resistance was insignificant. An emergence delay among resistant beetles from Bt corn slowed resistance evolution. A shift in the time of emergence for homozygous susceptible beetles from Bt corn did not have a significant effect on the evolution of Bt resistance in D. v. virgifera. This simulation study suggested that skewed toxin mortality in one sex and an emergence delay for beetles in Bt corn are not major concerns for managing resistance by D. v. virgifera to single-toxin or pyramided Bt corn. © 2013 Society of Chemical Industry.

  16. Feeding behavior of neonate Ostrinia nubilalis (Lepidoptera: Crambidae) on Cry1Ab Bt corn: implications for resistance management.

    Science.gov (United States)

    Razze, J M; Mason, C E; Pizzolato, T D

    2011-06-01

    The European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), is an economically important insect pest of corn, Zea mays L., in the United States and Canada. The development of genetically modified corn expressing genes derived from Bacillus thuringiensis (Bt) that encodes insecticidal crystalline (Cry) proteins has proven to be effective in controlling this insect. To assess the feeding behavior of neonate O. nubilalis on Bt corn, we examined differences in feeding behavior, based on presence of plant material in the gut, between Cry1Ab Bt corn and non-Bt near isoline corn for four intervals over a 48-h period. Feeding experiments revealed that there was significantly less feeding on Bt corn compared with non-Bt near isoline corn. The behavior of neonates on the plant corresponded with the differences in feeding on the two corn lines. The findings also showed that > 50% of the larvae initially left the plant before there was evidence in the gut of feeding regardless of whether the source was Bt or non-Bt corn. A higher quantity of plant material was found in the gut of larvae recovered from leaves of non-Bt compared with Bt corn. At the end of 48 h among the larvae that had left the plant, a greater proportion from Bt corn had plant material in the gut than did those from non-Bt corn.

  17. Evaluation of Bt Corn with Pyramided Genes on Efficacy and Insect Resistance Management for the Asian Corn Borer in China.

    Directory of Open Access Journals (Sweden)

    Fan Jiang

    Full Text Available A Bt corn hybrid (AcIe with two Bt genes (cry1Ie and cry1Ac was derived by breeding stack from line expressing Cry1Ie and a line expressing Cry1Ac. Efficacy of this pyramided Bt corn hybrid against the Asian corn borer (ACB, Ostrinia furnacalis, was evaluated. We conducted laboratory bioassays using susceptible and resistant ACB strains fed on artificial diet or fresh plant tissues. We also conducted field trials with artificial infestations of ACB neonates at the V6 and silk stages. The toxin-diet bioassay data indicated that mixtures of Cry1Ac and Cry1Ie proteins had synergistic insecticidal efficacy. The plant tissue bioassay data indicated that Bt corn hybrids expressing either a single toxin (Cry1Ac or Cry1Ie or two toxins had high efficacy against susceptible ACB. Damage ratings in the field trials indicated that the Bt corn hybrids could effectively protect against 1st and the 2nd generation ACB in China. The hybrid line with two Bt genes showed a higher efficacy against ACB larvae resistant to Cry1Ac or CryIe than the hybrid containing one Bt gene, and the two gene hybrid would have increased potential for managing or delaying the evolution of ACB resistance to Bt corn plants.

  18. Evaluation of Bt Corn with Pyramided Genes on Efficacy and Insect Resistance Management for the Asian Corn Borer in China.

    Science.gov (United States)

    Jiang, Fan; Zhang, Tiantao; Bai, Shuxiong; Wang, Zhenying; He, Kanglai

    2016-01-01

    A Bt corn hybrid (AcIe) with two Bt genes (cry1Ie and cry1Ac) was derived by breeding stack from line expressing Cry1Ie and a line expressing Cry1Ac. Efficacy of this pyramided Bt corn hybrid against the Asian corn borer (ACB), Ostrinia furnacalis, was evaluated. We conducted laboratory bioassays using susceptible and resistant ACB strains fed on artificial diet or fresh plant tissues. We also conducted field trials with artificial infestations of ACB neonates at the V6 and silk stages. The toxin-diet bioassay data indicated that mixtures of Cry1Ac and Cry1Ie proteins had synergistic insecticidal efficacy. The plant tissue bioassay data indicated that Bt corn hybrids expressing either a single toxin (Cry1Ac or Cry1Ie) or two toxins had high efficacy against susceptible ACB. Damage ratings in the field trials indicated that the Bt corn hybrids could effectively protect against 1st and the 2nd generation ACB in China. The hybrid line with two Bt genes showed a higher efficacy against ACB larvae resistant to Cry1Ac or CryIe than the hybrid containing one Bt gene, and the two gene hybrid would have increased potential for managing or delaying the evolution of ACB resistance to Bt corn plants.

  19. Areawide suppression of European corn borer with Bt maize reaps savings to non-Bt maize growers.

    Science.gov (United States)

    Hutchison, W D; Burkness, E C; Mitchell, P D; Moon, R D; Leslie, T W; Fleischer, S J; Abrahamson, M; Hamilton, K L; Steffey, K L; Gray, M E; Hellmich, R L; Kaster, L V; Hunt, T E; Wright, R J; Pecinovsky, K; Rabaey, T L; Flood, B R; Raun, E S

    2010-10-08

    Transgenic maize engineered to express insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has become widely adopted in U.S. agriculture. In 2009, Bt maize was planted on more than 22.2 million hectares, constituting 63% of the U.S. crop. Using statistical analysis of per capita growth rate estimates, we found that areawide suppression of the primary pest Ostrinia nubilalis (European corn borer) is associated with Bt maize use. Cumulative benefits over 14 years are an estimated $3.2 billion for maize growers in Illinois, Minnesota, and Wisconsin, with more than $2.4 billion of this total accruing to non-Bt maize growers. Comparable estimates for Iowa and Nebraska are $3.6 billion in total, with $1.9 billion for non-Bt maize growers. These results affirm theoretical predictions of pest population suppression and highlight economic incentives for growers to maintain non-Bt maize refugia for sustainable insect resistance management.

  20. Current European corn borer, Ostrinia nubilalis, injury levels in the northeastern United States and the value of Bt field corn.

    Science.gov (United States)

    Bohnenblust, Eric W; Breining, James A; Shaffer, John A; Fleischer, Shelby J; Roth, Gregory W; Tooker, John F

    2014-11-01

    Recent evidence indicates that some populations of European corn borer (ECB), Ostrinia nubilalis (Hübner), have declined to historic lows owing to widespread adoption of Bt corn hybrids. To understand current ECB populations in Pennsylvania field corn, the authors assessed larval damage in Bt and non-Bt corn hybrids at 29 sites over 3 years. The influence of Bt adoption rates, land cover types and moth activity on levels of ECB damage was also considered. Bt hybrids reduced ECB damage when compared with non-Bt, but these differences inconsistently translated to higher yields and, because of higher seed costs, rarely improved profits. No relationships were detected between land use or Bt adoption and ECB damage rates, but positive relationships were found between plant damage and captures of Z-race ECB moths in pheromone traps in the PestWatch network. ECB damage levels were generally low and appear to be declining across Pennsylvania. In many locations, farmers may gain greater profits by planting competitive non-Bt hybrids; however, Bt hybrids remain valuable control options, particularly in the parts of Pennsylvania where ECB populations persist. Moth captures from PestWatch appear to provide insight into where Bt hybrids are most valuable. © 2013 Society of Chemical Industry.

  1. Occurrence and larval movement of Diatraea saccharalis (Lepidoptera: Crambidae) in seed mixes of non-Bt and Bt pyramid corn.

    Science.gov (United States)

    Wangila, David S; Leonard, B Rogers; Ghimire, Mukti N; Bai, Yaoyu; Zhang, Liping; Yang, Yunlong; Emfinger, Karla D; Head, Graham P; Yang, Fei; Niu, Ying; Huang, Fangneng

    2013-10-01

    Larval movement of target pest populations among Bt and non-Bt plants is a major concern in the use of a seed mixture refuge strategy for Bt resistance management. In this study, occurrence and larval movement of the sugarcane borer, Diatraea saccharalis (F.), were evaluated in four planting patterns of non-Bt and Bt plants containing Genuity® SmartStax(TM) traits in 2009-2011. The four planting patterns were: (1) a pure stand of 27 Bt plants; (2) one non-Bt plant in the center, surrounded by 26 Bt plants; (3) a pure stand of 27 non-Bt plants; (4) one Bt plant in the center, surrounded by 26 non-Bt plants. Studies were conducted under four conditions: (1) open field with natural infestation; (2) greenhouse with artificial infestations; open field with artificial infestations (3) on the center plants only and (4) on every plant. The major objective of this study was to determine whether refuge plants in a seed mixture strategy could provide a comparable refuge population of D. saccharalis to a 'structured refuge' planting. Larvae of D. saccharalis showed the ability to move from infested plants to at least four plants away, as well as to adjacent rows, but the majority remained within the infested row. However, the number of larvae found on the non-Bt plants in the mixture plantings was not significantly reduced compared with the pure stand of non-Bt corn. The results of this study show that refuge plants in a seed mixture may be able to provide a comparable refuge population of D. saccharalis to a structured refuge planting. © 2013 Society of Chemical Industry.

  2. Biological activity of Bt proteins expressed in different structures of transgenic corn against Spodoptera frugiperda

    OpenAIRE

    Bernardi, Daniel; Bernardi, Oderlei; Horikoshi, Renato Jun; Salmeron, Eloisa; Okuma, Daniela Miyuki; Omoto, Celso

    2016-01-01

    ABSTRACT: Spodoptera frugiperda (J. E. Smith) is the main target pest of Bt corn technologies, such as YieldGard VT PRO(tm) (Cry1A.105/Cry2Ab2) and PowerCore(tm) (Cry1A.105/Cry2Ab2/Cry1F). In this study, it was evaluated the biological activity of Bt proteins expressed in different plant structures of YieldGard VT PRO(tm) and PowerCore(tm) corn against S. frugiperda . Complete mortality of S. frugiperda neonates was observed on leaf-disc of both Bt corn technologies. However, the mortality ...

  3. Susceptibility of Nebraska Western Corn Rootworm (Coleoptera: Chrysomelidae) Populations to Bt Corn Events.

    Science.gov (United States)

    Wangila, David S; Gassmann, Aaron J; Petzold-Maxwell, Jennifer L; French, B Wade; Meinke, Lance J

    2015-04-01

    Transgenic plants have been widely adopted by growers to manage the western corn rootworm, Diabrotica virgifera virgifera LeConte, in field corn. Because of reduced efficacy in some Nebraska fields after repeated use of Cry3Bb1-expressing hybrids, single plant bioassays were conducted in 2012 and 2013 to characterize the susceptibility of western corn rootworm populations to the rootworm-active proteins Cry3Bb1, mCry3A, and Cry34/35Ab1. Results demonstrate that there are heritable differences in susceptibility of Nebraska western corn rootworm populations to rootworm-active Bt traits. Proportional survival and corrected survival data coupled with field histories collectively support the conclusion that a level of field resistance to Cry3Bb1 has evolved in some Nebraska populations in response to selection pressure and that cross-resistance exists between Cry3Bb1 and mCry3A. There was no apparent cross-resistance between Cry34/35Ab1 and either Cry3Bb1 or mCry3A. The potential implications of these results on current and future corn rootworm management strategies are discussed. © 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.

  4. The Cultivation of Bt Corn Producing Cry1Ac Toxins Does Not Adversely Affect Non-Target Arthropods

    OpenAIRE

    Guo, Yanyan; Feng, Yanjie; Ge, Yang; Tetreau, Guillaume; Chen, Xiaowen; Dong, Xuehui; Shi, Wangpeng

    2014-01-01

    Transgenic corn producing Cry1Ac toxins from Bacillus thuringiensis (Bt) provides effective control of Asian corn borer, Ostrinia furnacalis (Guenée), and thus reduces insecticide applications. However, whether Bt corn exerts undesirable effects on non-target arthropods (NTAs) is still controversial. We conducted a 2-yr study in Shangzhuang Agricultural Experiment Station to assess the potential impact of Bt corn on field population density, biodiversity, community composition and structure o...

  5. The cultivation of Bt corn producing Cry1Ac toxins does not adversely affect non-target arthropods.

    Directory of Open Access Journals (Sweden)

    Yanyan Guo

    Full Text Available Transgenic corn producing Cry1Ac toxins from Bacillus thuringiensis (Bt provides effective control of Asian corn borer, Ostrinia furnacalis (Guenée, and thus reduces insecticide applications. However, whether Bt corn exerts undesirable effects on non-target arthropods (NTAs is still controversial. We conducted a 2-yr study in Shangzhuang Agricultural Experiment Station to assess the potential impact of Bt corn on field population density, biodiversity, community composition and structure of NTAs. On each sampling date, the total abundance, Shannon's diversity index, Pielou's evenness index and Simpson's diversity index were not significantly affected by Bt corn as compared to non-Bt corn. The "sampling dates" had a significant effect on these indices, but no clear tendencies related to "Bt corn" or "sampling dates X corn variety" interaction were recorded. Principal response curve analysis of variance indicated that Bt corn did not alter the distribution of NTAs communities. Bray-Curtis dissimilarity and distance analysis showed that Cry1Ac toxin exposure did not increase community dissimilarities between Bt and non-Bt corn plots and that the evolution of non-target arthropod community was similar on the two corn varieties. The cultivation of Bt corn failed to show any detrimental evidence on the density of non-target herbivores, predators and parasitoids. The composition of herbivores, predators and parasitoids was identical in Bt and non-Bt corn plots. Taken together, results from the present work support that Bt corn producing Cry1Ac toxins does not adversely affect NTAs.

  6. Effects of Bacillus thuringiensis (Bt) corn on soil Folsomia fimetaria, Folsomia candida (Collembola), Hypoaspis aculeifer (Acarina) and Enchytraeus crypticus (Oligochaeta)

    DEFF Research Database (Denmark)

    Ke, X.; Krogh, P. H.

    The effects of the Cry1Ab toxin from Bacillus thuringiensis (corn variety Cascade Bt MON810 and DeKalb variety 618 Bt) were studied on survival and reproduction of the soil collembolan Folsomia fimetaria, Folsomia candida, the collembolan predator mite Hypoaspis aculeifer and enchytraeids....... There was a weak significant reduction by 30% on the reproduction of F. fimetaria fed Bt corn in Petri dishes for 21 days. Likewise there was a weak significant reduction by 40% of the reproduction of H. aculeifer by Bt corn in amounts corresponding to 20 g plant material kg-1 soil in the two species soil......-litter microcosm systems. There were no effects of Bt corn materials on the reproduction of F. fimetaria and E. crypticus in the single species soil-litter microcosms. No effects of Bt corn materials on mortality of all the 4 species were observed in all treatments. The tendency of effects of the Bt corn...

  7. [Effects of Bt corn straw insecticidal proteins on enzyme activities of Eisenia fetida].

    Science.gov (United States)

    Shu, Ying-hua; Ma, Hong-hui; Du, Yan; Wang, Jian-wu

    2011-08-01

    Bacillus thuringiensis (Bt) proteins released from Bt corn can enter soil ecosystem via returning straw into field, root exudation, and pollen fluttering-down. In this study, the straws of Bt corn and its near-isogenic non-Bt line were added into soil with an application rate of 5% and 7.5% to breed Eisenia fetida, and the total protein content and the activities of acetylcholine esterase (AchE), glutathione peroxidase (GSH-PX), catalase (CAT), and superoxide dismutase (SOD) in E. fetida were determined after 7 and 14 days. Under the same application rate of the straws, the total protein content and GSH-PX activity of E. fetida decreased while the AchE, CAT, and SOD activities increased on the 14th day, compared with those on the 7th day. The Bt corn straw increased the SOD activity and decreased the AchE and GSH-PX activities, but had less effects on the total protein content and CAT activity, compared with non-Bt corn straw. All the results suggested that Bt corn straw had no inhibitory effect on E. fetida total protein but could inhibit the AchE and GSH-PX activities, and could not induce CAT activity but induce SOD activity within a short time.

  8. Dynamics of mycotoxin and Aspergillus flavus levels in aging Bt and non-Bt corn residues under Mississippi no-till conditions.

    Science.gov (United States)

    Abbas, Hamed K; Accinelli, Cesare; Zablotowicz, Robert M; Abel, Craig A; Bruns, H Arnold; Dong, Yanhong; Shier, W Thomas

    2008-08-27

    Mycotoxin and Aspergillus flavus levels in soil-surface corn debris left by no-till agriculture methods (stover, cobs, and cobs with grain) were determined during the December-March fallow period for near-isogenic Bt and non-Bt hybrid corn. By December, average mycotoxin levels in non-Bt corn were many times higher in cobs with grain than in grain harvested in September (total aflatoxins, 774 vs 211 ng/g; total fumonisins, 216 vs 3.5 microg/g; cyclopiazonic acid, 4102 vs 72.2 microg/g; zearalenone, 0.2 vs corn debris fractions decreased during winter but began to rise in March. Levels of all mycotoxins and A. flavus propagules were lower in harvested grain and debris from Bt than non-Bt corn, but differences were significant (p < 0.05) only for aflatoxins.

  9. Effects of Bt Corn and Egg Density on Western Corn Rootworm (Coleoptera: Chrysomelidae) Adult Emergence and Estimation of Effective Bt Dose.

    Science.gov (United States)

    Campbell, L A; Prasifka, P L; Storer, N P; Rule, D M; Hendrix, W H

    2017-04-01

    Since 2003, rootworm-protected transgenic corn has been commercially deployed in the United States as a principal method of control of western corn rootworm, Diabrotica virgifera virgifera LeConte. Durability of this technology depends partly on larval mortality ("dose") exerted by the traits, but density-dependent mortality can confound calculations of dose. Research reported here examined the effects of density-dependent mortality on adult emergence and estimates of trait dose. At sites in Illinois and Indiana, western corn rootworm eggs were infested at four densities on non-Bt corn and at a single density on corn hybrids with transgenic events MON 88017 (VT Triple PRO), DAS-59122-7 (Herculex Insect Protection), and MON 88017 × DAS-59122-7 (SmartStax corn). Beetles were collected weekly in large emergence cages. Density-dependent mortality and the effect of Bt traits were examined using percent survival from egg to adult, sex ratio, and beetle mass. Beetle emergence from Bt treatments was very low, and percent survival from non-Bt treatments was greatest at the lowest egg density (410 eggs per row-meter). Therefore, emergence from the lowest infestation density on non-Bt corn was used to estimate the effective dose of the Bt treatments. Sex ratio and beetle mass were unaffected by density-dependent effects and were not consistently affected by Bt traits. Dose was estimated at 97.4-99.3% for MON 88017, 98.8-99.9% for DAS-59122-7, and 99.7-100.0% for MON 88017 × DAS-59122-7. This study confirms the need to account for density-dependent mortality when estimating dose of corn rootworm protection events even at relatively low egg infestation densities. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re

  10. Mechanism and DNA-based detection of field-evolved resistance to transgenic Bt corn in fall armyworm (Spodoptera frugiperda)

    Science.gov (United States)

    Evolution of resistance threatens sustainability of transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). The fall armyworm is a devastating pest controlled by transgenic Bt corn producing the Cry1Fa insecticidal protein. However, fall armyworm populations ...

  11. Transgenic Bt Corn, Soil Insecticide, and Insecticidal Seed Treatment Effects on Corn Rootworm (Coleoptera: Chrysomelidae) Beetle Emergence, Larval Feeding Injury, and Corn Yield in North Dakota.

    Science.gov (United States)

    Calles-Torrez, Veronica; Knodel, Janet J; Boetel, Mark A; Doetkott, Curt D; Podliska, Kellie K; Ransom, Joel K; Beauzay, Patrick; French, B Wade; Fuller, Billy W

    2018-02-09

    Northern, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), and western, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), corn rootworms are economic pests of corn, Zea mays L. in North America. We measured the impacts of corn hybrids incorporated with Cry3Bb1, Cry34/35Ab1, and pyramided (Cry3Bb1 + Cry34/35Ab1) Bacillus thuringiensis Berliner (Bt) proteins, tefluthrin soil insecticide, and clothianidin insecticidal seed treatment on beetle emergence, larval feeding injury, and corn yield at five locations from 2013 to 2015 in eastern North Dakota. In most cases, emergence was significantly lower in Bt-protected corn than in non-Bt corn hybrids. Exceptions included Wyndmere, ND (2013), where D. barberi emergence from Cry34/35Ab1 plots was not different from that in the non-Bt hybrid, and Arthur, ND (2013), where D. v. virgifera emergence from Cry3Bb1 plots did not differ from that in the non-Bt hybrid. Bt hybrids generally produced increased grain yield compared with non-Bt corn where rootworm densities were high, and larval root-feeding injury was consistently lower in Bt-protected plots than in non-Bt corn. The lowest overall feeding injury and emergence levels occurred in plots planted with the Cry3Bb1 + Cry34/35Ab1 hybrid. Time to 50% cumulative emergence of both species was 5-7 d later in Bt-protected than in non-Bt hybrids. Tefluthrin and clothianidin were mostly inconsequential in relation to beetle emergence and larval root injury. Our findings could suggest that some North Dakota populations could be in early stages of increased tolerance to some Bt toxins; however, Bt corn hybrids currently provide effective protection against rootworm injury in eastern North Dakota. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Fumonisin B1 toxicity in grower-finisher pigs: a comparative analysis of genetically engineered Bt corn and non-Bt corn by using quantitative dietary exposure assessment modeling.

    Science.gov (United States)

    Delgado, James E; Wolt, Jeffrey D

    2011-08-01

    In this study, we investigate the long-term exposure (20 weeks) to fumonisin B(1) (FB(1)) in grower-finisher pigs by conducting a quantitative exposure assessment (QEA). Our analytical approach involved both deterministic and semi-stochastic modeling for dietary comparative analyses of FB(1) exposures originating from genetically engineered Bacillus thuringiensis (Bt)-corn, conventional non-Bt corn and distiller's dried grains with solubles (DDGS) derived from Bt and/or non-Bt corn. Results from both deterministic and semi-stochastic demonstrated a distinct difference of FB(1) toxicity in feed between Bt corn and non-Bt corn. Semi-stochastic results predicted the lowest FB(1) exposure for Bt grain with a mean of 1.5 mg FB(1)/kg diet and the highest FB(1) exposure for a diet consisting of non-Bt grain and non-Bt DDGS with a mean of 7.87 mg FB(1)/kg diet; the chronic toxicological incipient level of concern is 1.0 mg of FB(1)/kg of diet. Deterministic results closely mirrored but tended to slightly under predict the mean result for the semi-stochastic analysis. This novel comparative QEA model reveals that diet scenarios where the source of grain is derived from Bt corn presents less potential to induce FB(1) toxicity than diets containing non-Bt corn.

  13. Fumonisin B1 Toxicity in Grower-Finisher Pigs: A Comparative Analysis of Genetically Engineered Bt Corn and non-Bt Corn by Using Quantitative Dietary Exposure Assessment Modeling

    Directory of Open Access Journals (Sweden)

    Jeffrey D. Wolt

    2011-07-01

    Full Text Available In this study, we investigate the long-term exposure (20 weeks to fumonisin B1 (FB1 in grower-finisher pigs by conducting a quantitative exposure assessment (QEA. Our analytical approach involved both deterministic and semi-stochastic modeling for dietary comparative analyses of FB1 exposures originating from genetically engineered Bacillus thuringiensis (Bt-corn, conventional non-Bt corn and distiller’s dried grains with solubles (DDGS derived from Bt and/or non-Bt corn. Results from both deterministic and semi-stochastic demonstrated a distinct difference of FB1 toxicity in feed between Bt corn and non-Bt corn. Semi-stochastic results predicted the lowest FB1 exposure for Bt grain with a mean of 1.5 mg FB1/kg diet and the highest FB1 exposure for a diet consisting of non-Bt grain and non-Bt DDGS with a mean of 7.87 mg FB1/kg diet; the chronic toxicological incipient level of concern is 1.0 mg of FB1/kg of diet. Deterministic results closely mirrored but tended to slightly under predict the mean result for the semi-stochastic analysis. This novel comparative QEA model reveals that diet scenarios where the source of grain is derived from Bt corn presents less potential to induce FB1 toxicity than diets containing non-Bt corn.

  14. Multi-state trials of Bt sweet corn varieties for control of the corn earworm (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Shelton, A M; Olmstead, D L; Burkness, E C; Hutchison, W D; Dively, G; Welty, C; Sparks, A N

    2013-10-01

    Field tests in 2010-2011 were performed in New York, Minnesota, Maryland, Ohio, and Georgia to compare Bt sweet corn lines expressing Cry1A.105 + Cry2Ab2 and Cry1Ab with their non-Bt isolines, with and without the use of foliar insecticides. The primary insect pest in all locations during the trial years was Heliocoverpa zea (Boddie), which is becoming the most serious insect pest of sweet corn in the United States. At harvest, the ears were measured for marketability according to fresh market and processing standards. For fresh market and processing, least squares regression showed significant effects of protein expression, state, and insecticide frequency. There was a significant effect of year for fresh market but not for processing. The model also showed significant effects of H. zea per ear by protein expression. Sweet corn containing two genes (Cry1A.105 + Cry2Ab2) and a single gene (Cry1Ab) provided high marketability, and both Bt varieties significantly outperformed the traditional non-Bt isolines in nearly all cases regardless of insecticide application frequency. For pest suppression of H. zea, plants expressing Bt proteins consistently performed better than non-Bt isoline plants, even those sprayed at conventional insecticide frequencies. Where comparisons in the same state were made between Cry1A.105 + Cry2Ab2 and Cry1Ab plants for fresh market, the product expressing Cry1A.105 + Cry2Ab2 provided better protection and resulted in less variability in control. Overall, these results indicate Cry1A.105 + Cry2Ab2 and Cry1Ab plants are suitable for fresh market and processing corn production across a diversity of growing regions and years. Our results demonstrate that Bt sweet corn has the potential to significantly reduce the use of conventional insecticides against lepidopteran pests and, in turn, reduce occupational and environmental risks that arise from intensive insecticide use.

  15. Biological activity of Bt proteins expressed in different structures of transgenic corn against Spodoptera frugiperda

    Directory of Open Access Journals (Sweden)

    Daniel Bernardi

    2016-06-01

    Full Text Available ABSTRACT: Spodoptera frugiperda (J. E. Smith is the main target pest of Bt corn technologies, such as YieldGard VT PRO(tm (Cry1A.105/Cry2Ab2 and PowerCore(tm (Cry1A.105/Cry2Ab2/Cry1F. In this study, it was evaluated the biological activity of Bt proteins expressed in different plant structures of YieldGard VT PRO(tm and PowerCore(tm corn against S. frugiperda . Complete mortality of S. frugiperda neonates was observed on leaf-disc of both Bt corn technologies. However, the mortality in silks and grains was lower than 50 and 6%, respectively. In addition, more than 49% of the surviving larvae in silks and grains completed the biological cycle. However, all life table parameters were negatively affected in insects that developed in silks and grains of both Bt corn events. In summary, the low biological activity of Bt proteins expressed on silks and grains of YieldGard VT PRO(tm and PowerCore(tm corn can contribute to the resistance evolution in S. frugiperda populations.

  16. Field assessment of Bt cry1Ah corn pollen on the survival, development and behavior of Apis mellifera ligustica.

    Science.gov (United States)

    Dai, Ping-Li; Zhou, Wei; Zhang, Jie; Cui, Hong-Juan; Wang, Qiang; Jiang, Wei-Yu; Sun, Ji-Hu; Wu, Yan-Yan; Zhou, Ting

    2012-05-01

    Honeybees may be exposed to insecticidal proteins from transgenic plants via pollen. An assessment of the impact of such exposures on the honeybee is an essential part of the risk assessment process for transgenic Bacillus thuringiensis corn. A field trial was conducted to evaluate the effect of transgenic Bt cry1Ah corn on the honeybee Apis mellifera ligustica. Colonies of honeybees were moved to Bt or non-Bt corn fields during anthesis and then sampled to record their survival, development and behavior. No differences in immature stages, worker survival, bee body weight, hypopharyngeal gland weight, colony performance, foraging activity or olfactory learning abilities were detected between colonies that were placed in non-Bt corn fields and those placed in Bt corn fields. We conclude that cry1Ah corn carries no risk for the survival, development, colony performance or behavior of the honeybee A. mellifera ligustica. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Early Detection and Mitigation of Resistance to Bt Maize by Western Corn Rootworm (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Andow, David A; Pueppke, Steven G; Schaafsma, Arthur W; Gassmann, Aaron J; Sappington, Thomas W; Meinke, Lance J; Mitchell, Paul D; Hurley, Terrance M; Hellmich, Richard L; Porter, R Pat

    2016-02-01

    Transgenic Bt maize that produces less than a high-dose has been widely adopted and presents considerable insect resistance management (IRM) challenges. Western corn rootworm, Diabrotica virgifera virgifera LeConte, has rapidly evolved resistance to Bt maize in the field, leading to local loss of efficacy for some corn rootworm Bt maize events. Documenting and responding to this resistance has been complicated by a lack of rapid diagnostic bioassays and by regulatory triggers that hinder timely and effective management responses. These failures are of great concern to the scientific and agricultural community. Specific challenges posed by western corn rootworm resistance to Bt maize, and more general concerns around Bt crops that produce less than a high-dose of Bt toxin, have caused uncertainty around current IRM protocols. More than 15 years of experience with IRM has shown that high-dose and refuge-based IRM is not applicable to Bt crops that produce less than a high-dose. Adaptive IRM approaches and pro-active, integrated IRM-pest management strategies are needed and should be in place before release of new technologies that produce less than a high-dose. We suggest changes in IRM strategies to preserve the utility of corn rootworm Bt maize by 1) targeting local resistance management earlier in the sequence of responses to resistance and 2) developing area-wide criteria to address widespread economic losses. We also favor consideration of policies and programs to counteract economic forces that are contributing to rapid resistance evolution. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  18. 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.

  19. Fumonisin B1 Toxicity in Grower-Finisher Pigs: A Comparative Analysis of Genetically Engineered Bt Corn and non-Bt Corn by Using Quantitative Dietary Exposure Assessment Modeling

    OpenAIRE

    Delgado, James E.; Wolt, Jeffrey D.

    2011-01-01

    In this study, we investigate the long-term exposure (20 weeks) to fumonisin B1 (FB1) in grower-finisher pigs by conducting a quantitative exposure assessment (QEA). Our analytical approach involved both deterministic and semi-stochastic modeling for dietary comparative analyses of FB1 exposures originating from genetically engineered Bacillus thuringiensis (Bt)-corn, conventional non-Bt corn and distiller’s dried grains with solubles (DDGS) derived from Bt and/or non-Bt corn. Results from bo...

  20. Insect Damage, Aflatoxin Content, and Yield of Bt Corn in Alabama.

    Science.gov (United States)

    Bowen, K L; Flanders, K L; Hagan, A K; Ortiz, B

    2014-10-01

    Isoline pairs of hybrid corn, similar except for presence or absence of a Bt trait, were planted at eight sites across Alabama over three years. This study evaluated insect damage, yield, and aflatoxin levels as affected by the Bt traits, YieldGard Corn Borer (expressing Cry1Ab), Herculex I (expressing Cry1F), Genuity VT Triple PRO (expressing Cry1A.105 and Cry2Ab2), Agrisure Viptera 3111 (expressing Vip3Aa20 and Cry1Ab), and Genuity SmartStax (expressing Cry1A.105, Cry2Ab2, and Cry1F). When examined over all sites and years, hybrids with any of the included Bt traits had lower insect damage and higher yields. However, insect damage was not consistently correlated to yield. Bt traits expressing multiple proteins provided greater protection from corn earworm feeding than did traits for single proteins. Yields and aflatoxin levels were highly variable among sites although irrigated sites had higher yields than nonirrigated sites. Aflatoxins commonly accumulate in corn in the southeastern United States because of prevailing high temperatures and frequent dry conditions. Aflatoxin levels were not consistently associated with any factors that were evaluated, including Bt traits. © 2014 Entomological Society of America.

  1. Exposure and nontarget effects of transgenic Bt corn debris in streams.

    Science.gov (United States)

    Jensen, Peter D; Dively, Galen P; Swan, Christopher M; Lamp, William O

    2010-04-01

    Corn (Zea mays L.) transformed with a gene from the bacterium Bacillus thuringiensis (Bt) comprises 49% of all corn in the United States. The input of senesced corn tissue expressing the Bt gene may impact stream-inhabiting invertebrates that process plant debris, especially trichopteran species related to the target group of lepidopteran pests. Our goal was to assess risk associated with transgenic corn debris entering streams. First, we show the input of corn tissue after harvest was extended over months in a stream. Second, using laboratory bioassays based on European corn borer [Ostrinia nubilalis (Hübner)], we found no bioactivity of Cry1Ab protein in senesced corn tissue after 2 wk of exposure to terrestrial or aquatic environments. Third, we show that Bt near-isolines modify growth and survivorship of some species of invertebrates. Of the four nontarget invertebrate species fed Bt near-isolines, growth of two closely related trichopterans was not negatively affected, whereas a tipulid crane fly exhibited reduced growth rates, and an isopod exhibited reduced growth and survivorship on the Cry1Ab near-isoline but not on the stacked Cry1Ab + Cry3Bb1 near-isoline. Because of lack of evidence of bioactivity of Bt after 2 wk and because of lack of nontarget effects on the stacked near-isoline, we suggest that tissue-mediated differences, and not the presence of the Cry1Ab protein, caused the different responses among the species. Overall, our results provide evidence that adverse effects to aquatic nontarget shredders involve complex interactions arising from plant genetics and environment that cannot be ascribed to the presence of Cry1Ab proteins.

  2. Supplemental control of lepidopterous pests on Bt transgenic sweet corn with biologically-based spray treatments.

    Science.gov (United States)

    Farrar, Robert R; Shepard, B Merle; Shapiro, Martin; Hassell, Richard L; Schaffer, Mark L; Smith, Chad M

    2009-01-01

    Biologically-based spray treatments, including nucleopolyhedroviruses, neem, and spinosad, were evaluated as supplemental controls for the fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), on transgenic sweet corn, Zea mays (L.) (Poales: Poaceae), expressing a Cry1Ab toxin from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt). Overall, transgenic corn supported lower densities of both pests than did nontransgenic corn. Control of the fall armyworm was improved in both whorl-stage and tassel-stage corn by the use of either a nucleopolyhedrovirus or neem, but the greatest improvement was seen with spinosad. Only spinosad consistently reduced damage to ears, which was caused by both pest species. In general, efficacy of the spray materials did not differ greatly between transgenic and nontransgenic corn.

  3. Decomposition rates and residue-colonizing microbial communities of Bacillus thuringiensis insecticidal protein Cry3Bb-expressing (Bt) and non-Bt corn hybrids in the field.

    Science.gov (United States)

    Xue, Kai; Serohijos, Raquel C; Devare, Medha; Thies, Janice E

    2011-02-01

    Despite the rapid adoption of crops expressing the insecticidal Cry protein(s) from Bacillus thuringiensis (Bt), public concern continues to mount over the potential environmental impacts. Reduced residue decomposition rates and increased tissue lignin concentrations reported for some Bt corn hybrids have been highlighted recently as they may influence soil carbon dynamics. We assessed the effects of MON863 Bt corn, producing the Cry3Bb protein against the corn rootworm complex, on these aspects and associated decomposer communities by terminal restriction fragment length polymorphism (T-RFLP) analysis. Litterbags containing cobs, roots, or stalks plus leaves from Bt and unmodified corn with (non-Bt+I) or without (non-Bt) insecticide applied were placed on the soil surface and at a 10-cm depth in field plots planted with these crop treatments. The litterbags were recovered and analyzed after 3.5, 15.5, and 25 months. No significant effect of treatment (Bt, non-Bt, and non-Bt+I) was observed on initial tissue lignin concentrations, litter decomposition rate, or bacterial decomposer communities. The effect of treatment on fungal decomposer communities was minor, with only 1 of 16 comparisons yielding separation by treatment. Environmental factors (litterbag recovery year, litterbag placement, and plot history) led to significant differences for most measured variables. Combined, these results indicate that the differences detected were driven primarily by environmental factors rather than by any differences between the corn hybrids or the use of tefluthrin. We conclude that the Cry3Bb corn tested in this study is unlikely to affect carbon residence time or turnover in soils receiving these crop residues.

  4. The Reflexive Producer: The Influence of Farmer Knowledge upon the Use of Bt Corn

    Science.gov (United States)

    Kaup, Brent Z.

    2008-01-01

    This paper examines the influence of farmer knowledge upon decision making processes. Drawing upon the sociological debates around the ideas of reflexive modernity and biotechnology as well as from classic adoption and diffusion studies, I explore the influences upon farmers' use of "Bacillus thuringiensis" (Bt) corn. Utilizing survey data…

  5. Emergence and Abundance of Western Corn Rootworm (Coleoptera: Chrysomelidae) in Bt Cornfields With Structured and Seed Blend Refuges.

    Science.gov (United States)

    Hughson, Sarah A; Spencer, Joseph L

    2015-02-01

    To slow evolution of western corn rootworm (Diabrotica virgifera virgifera LeConte) resistance to Bt (Bacillus thuringiensis Berliner) corn hybrids, non-Bt "refuges" must be planted within or adjacent to Bt cornfields, allowing susceptible insects to develop without exposure to Bt toxins. Bt-susceptible adults from refuges are expected to find and mate with resistant adults that have emerged from Bt corn, reducing the likelihood that Bt-resistant offspring are produced. The spatial and temporal distribution of adults in four refuge treatments (20, 5, and 0% structured refuges and 5% seed blend) and adjacent soybean fields was compared from 2010 to 2012. Adult emergence (adults/trap/day) from refuge corn in structured refuge treatments was greater than that from Bt corn, except during the post-pollination period of corn phenology when emergence from refuge and Bt plants was often the same. Abundance of free-moving adults was greatest in and near refuge rows in structured refuge treatments during vegetative and pollination periods. By post-pollination, adult abundance became evenly distributed. In contrast, adult abundance in 5% seed blends and 0% refuges was evenly distributed, or nearly so, across plots throughout the season. The persistent concentration of adults in refuge rows suggests that structured refuge configurations may not facilitate the expected mixing of adults from refuge and Bt corn. Seed blends produce uniform distributions of adults across the field that may facilitate mating between Bt and refuge adults and ultimately delay the evolution of Bt resistance. © 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.

  6. Field-evolved resistance to Bt maize by western corn rootworm.

    Directory of Open Access Journals (Sweden)

    Aaron J Gassmann

    Full Text Available BACKGROUND: Crops engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt are planted on millions of hectares annually, reducing the use of conventional insecticides and suppressing pests. However, the evolution of resistance could cut short these benefits. A primary pest targeted by Bt maize in the United States is the western corn rootworm Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae. METHODOLOGY/PRINCIPAL FINDINGS: We report that fields identified by farmers as having severe rootworm feeding injury to Bt maize contained populations of western corn rootworm that displayed significantly higher survival on Cry3Bb1 maize in laboratory bioassays than did western corn rootworm from fields not associated with such feeding injury. In all cases, fields experiencing severe rootworm feeding contained Cry3Bb1 maize. Interviews with farmers indicated that Cry3Bb1 maize had been grown in those fields for at least three consecutive years. There was a significant positive correlation between the number of years Cry3Bb1 maize had been grown in a field and the survival of rootworm populations on Cry3Bb1 maize in bioassays. However, there was no significant correlation among populations for survival on Cry34/35Ab1 maize and Cry3Bb1 maize, suggesting a lack of cross resistance between these Bt toxins. CONCLUSIONS/SIGNIFICANCE: This is the first report of field-evolved resistance to a Bt toxin by the western corn rootworm and by any species of Coleoptera. Insufficient planting of refuges and non-recessive inheritance of resistance may have contributed to resistance. These results suggest that improvements in resistance management and a more integrated approach to the use of Bt crops may be necessary.

  7. Field-evolved resistance to Bt maize by western corn rootworm.

    Science.gov (United States)

    Gassmann, Aaron J; Petzold-Maxwell, Jennifer L; Keweshan, Ryan S; Dunbar, Mike W

    2011-01-01

    Crops engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are planted on millions of hectares annually, reducing the use of conventional insecticides and suppressing pests. However, the evolution of resistance could cut short these benefits. A primary pest targeted by Bt maize in the United States is the western corn rootworm Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). We report that fields identified by farmers as having severe rootworm feeding injury to Bt maize contained populations of western corn rootworm that displayed significantly higher survival on Cry3Bb1 maize in laboratory bioassays than did western corn rootworm from fields not associated with such feeding injury. In all cases, fields experiencing severe rootworm feeding contained Cry3Bb1 maize. Interviews with farmers indicated that Cry3Bb1 maize had been grown in those fields for at least three consecutive years. There was a significant positive correlation between the number of years Cry3Bb1 maize had been grown in a field and the survival of rootworm populations on Cry3Bb1 maize in bioassays. However, there was no significant correlation among populations for survival on Cry34/35Ab1 maize and Cry3Bb1 maize, suggesting a lack of cross resistance between these Bt toxins. This is the first report of field-evolved resistance to a Bt toxin by the western corn rootworm and by any species of Coleoptera. Insufficient planting of refuges and non-recessive inheritance of resistance may have contributed to resistance. These results suggest that improvements in resistance management and a more integrated approach to the use of Bt crops may be necessary.

  8. Effect of insertion of Bt gene in corn and different fumonisin content on growth performance of weaned piglets

    Directory of Open Access Journals (Sweden)

    Filippo Rossi

    2010-05-01

    Full Text Available The objective of this study was to compare the effect of Bt corn and isogenic corn on the growth of weaned piglets. One hundred and twenty-eight weaned piglets weighing 8.8±1.27 kg live weight were randomly assigned to 4 groups of 32 animals each (16 castrated males and 16 females. Bt corn (line MON810 and isogenic corn were produced at two farms located in the provinces of Lodi and Venice (northern Italy. The Bt corn had the same chemical composition as the isogenic corn but a lower content of fumonisin B1 (FB1. The experimental period (35 days was in 2 phases, 0-14 d and 15-35 d. There was no significant difference in average daily gain (ADG among groups during the first feeding phase. Compared to animals fed isogenic corn, the piglets fed Bt maize gained more weight during the second feeding phase (Bt: 464.1 g/d, isogenic: 429.1 g/d; P<0.05. Also, the ADG over the entire trial was higher in piglets fed Bt corn versus piglets fed isogenic corn (Bt: 396.4 g/d, isogenic: 374.1 g/d; P<0.05. The ADG of the whole period decreased linearly (P<0.05 with respect to the FB1 content of the diet. Final weight was higher in piglets fed the diet containing Bt corn (Bt: 22.68 kg, isogenic: 21.83 kg; P<0.05. No differences in feed intake and in the feed:gain ratio were observed, although a linear response between FB1 and feed:gain ratio in first 14 days of the experiment was detected.

  9. Effect of insertion of Bt gene in corn and different fumonisin content on growth performance of weaned piglets

    Directory of Open Access Journals (Sweden)

    Filippo Rossi

    2011-04-01

    Full Text Available The objective of this study was to compare the effect of Bt corn and isogenic corn on the growth of weaned piglets. One hundred twenty-eight weaned piglets weighing 8.8 ±1.27 kg live weight were randomly assigned to 4 groups of 32 animals each (16 castrated males and 16 females. Bt corn (line MON810 and isogenic corn were produced at two farms located in the Lodi and Venezia provinces (northern Italy. Bt corn had the same chemical composition as the isogenic corn but a lower content of fumonisin B1 (FB1. The experimental period (35 days was divided into two phases: 0-14 d and 15-35 d. There was no significant difference in average daily gain (ADG among groups during the first feeding phase. Compared to animals fed isogenic corn, the piglets fed Bt maize gained more weight during the second feeding phase (Bt: 464.1 g/d, isogenic: 429.1 g/d; P < 0.05. Also, the ADG over the entire trial was higher in piglets fed Bt corn versus piglets fed isogenic corn (Bt: 396.4 g/d, isogenic: 374.1 g/d; P < 0.05. The ADG of the whole period decreased linearly (P<0.05 with respect to FB1 content of diet. Final weight was higher in piglets fed the diet containing Bt corn (Bt: 22.68 kg, isogenic: 21.83 kg; P < 0.05. No differences in feed intake and in the feed:gain ratio were observed, however a linear response between FB1 and feed:gain ratio in first 14 days of the experiment was detected.

  10. Western corn rootworm and Bt maize: challenges of pest resistance in the field.

    Science.gov (United States)

    Gassmann, Aaron J; Petzold-Maxwell, Jennifer L; Keweshan, Ryan S; Dunbar, Mike W

    2012-01-01

    Crops genetically engineered to produce insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) manage many key insect pests while reducing the use of conventional insecticides. One of the primary pests targeted by Bt maize in the United States is the western corn rootworm, Diabrotica virgifera virgifera LeConte. Beginning in 2009, populations of western corn rootworm were identified in Iowa, USA that imposed severe root injury to Cry3Bb1 maize. Subsequent laboratory bioassays revealed that these populations were resistant to Cry3Bb1 maize, with survival on Cry3Bb1 maize that was three times higher than populations not associated with such injury. Here we report the results of research that began in 2010 when western corn rootworm were sampled from 14 fields in Iowa, half of which had root injury to Cry3Bb1 maize of greater than 1 node. Of these samples, sufficient eggs were collected to conduct bioassays on seven populations. Laboratory bioassays revealed that these 2010 populations had survival on Cry3Bb1 maize that was 11 times higher and significantly greater than that of control populations, which were brought into the laboratory prior to the commercialization of Bt maize for control of corn rootworm. Additionally, the developmental delays observed for control populations on Cry3Bb1 maize were greatly diminished for 2010 populations. All 2010 populations evaluated in bioassays came from fields with a history of continuous maize production and between 3 and 7 y of Cry3Bb1 maize cultivation. Resistance to Cry34/35Ab1 maize was not detected and there was no correlation between survival on Cry3Bb1 maize and Cry34/35Ab1 maize, suggesting a lack of cross resistance between these Bt toxins. Effectively dealing with the challenge of field-evolved resistance to Bt maize by western corn rootworm will require better adherence to the principles of integrated pest management.

  11. Managing the sugarcane borer, Diatraea saccharalis, and corn earworm, Helicoverpa zea, using Bt corn and insecticide treatments.

    Science.gov (United States)

    Farias, Juliano R; Costa, Ervandil C; Guedes, Jerson V C; Arbage, Alessandro P; Neto, Armando B; Bigolin, Mauricio; Pinto, Felipe F

    2013-01-01

    The sugarcane borer, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) and the corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), are important pests of corn in Brazil and have not been successfully managed, because of the difficulty of managing them with pesticides. The objective of this study was to evaluate the effect of Bt corn MON810, transformed with a gene from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) insecticide seed treatment, and foliar insecticide spray using treatments developed for control of the fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), which is the major pest of corn. The experiments were done under field conditions in early- and late-planted corn in the state of Rio Grande do Sul, Brazil, and in the laboratory. The MON810 corn reduced infestations and damage by D. saccharalis and H. zea. The insecticides used in seed treatments or foliar sprays did not affect D. saccharalis and H. zea infestations or damage levels. The exception was the insecticide seed treatment in non-transformed corn, which reduced early infestations of D. saccharalis. The MON810 corn, therefore, can be used for managing these two pest species, especially D. saccharalis.

  12. Do Sesamia nonagrioides (Lepidoptera; Noctuidae) gravid females discriminate between Bt or multivitamin corn varieties? Role of olfactory and visual cues.

    Science.gov (United States)

    Cruz, Diego; Eizaguirre, Matilde

    2015-01-01

    The Mediterranean corn borer, Sesamia nonagrioides Lefèbvre, is a key pest of corn and a main target of Bacillus thuringiensis (Bt) corn in Northeast Spain. Trends for future biotechnology crops indicate that Bt, non-Bt, and stacked corn varieties with metabolic pathways for vitamin-increased traits could coexist in same region. Knowledge of the oviposition response of gravid females of S. nonagrioides to these different varieties could be extremely important for managing strategies aimed for delaying resistance development. In dual-choice assays, we examined the host preference of gravid females of S. nonagrioides for four corn varieties: a new transgenic corn with increased vitamin levels, its near isogenic counterpart (M37W), a Bt corn plant, and its near isogenic counterpart. Olfactory cues were the predominant ones when gravid females looked for a suitable host to lay eggs, and no synergistic effects were observed when both visual and olfactory cues were present. When the plant was visible, the females preferred the odors emitted by the nontransgenic to its multivitamin transgenic counterpart and when they only could detect the volatiles they also preferred the nontransgenic M37W variety to the Bt corn variety. If gravid females are less attracted to corn with an increased level of vitamins, this could impact insect resistance management and the value of refuge plants, if such traits are stacked with an insect resistance trait. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  13. Evidence of field-evolved resistance of Spodoptera frugiperda to Bt corn expressing Cry1F in Brazil that is still sensitive to modified Bt toxins.

    Science.gov (United States)

    Monnerat, Rose; Martins, Erica; Macedo, Cristina; Queiroz, Paulo; Praça, Lilian; Soares, Carlos Marcelo; Moreira, Helio; Grisi, Isabella; Silva, Joseane; Soberon, Mario; Bravo, Alejandra

    2015-01-01

    Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt) in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab). Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV) from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda.

  14. Evidence of field-evolved resistance of Spodoptera frugiperda to Bt corn expressing Cry1F in Brazil that is still sensitive to modified Bt toxins.

    Directory of Open Access Journals (Sweden)

    Rose Monnerat

    Full Text Available Brazil ranked second only to the United States in hectares planted to genetically modified crops in 2013. Recently corn producers in the Cerrado region reported that the control of Spodoptera frugiperda with Bt corn expressing Cry1Fa has decreased, forcing them to use chemicals to reduce the damage caused by this insect pest. A colony of S. frugiperda was established from individuals collected in 2013 from Cry1Fa corn plants (SfBt in Brazil and shown to have at least more than ten-fold higher resistance levels compared with a susceptible colony (Sflab. Laboratory assays on corn leaves showed that in contrast to SfLab population, the SfBt larvae were able to survive by feeding on Cry1Fa corn leaves. The SfBt population was maintained without selection for eight generations and shown to maintain high levels of resistance to Cry1Fa toxin. SfBt showed higher cross-resistance to Cry1Aa than to Cry1Ab or Cry1Ac toxins. As previously reported, Cry1A toxins competed the binding of Cry1Fa to brush border membrane vesicles (BBMV from SfLab insects, explaining cross-resistance to Cry1A toxins. In contrast Cry2A toxins did not compete Cry1Fa binding to SfLab-BBMV and no cross-resistance to Cry2A was observed, although Cry2A toxins show low toxicity to S. frugiperda. Bioassays with Cry1AbMod and Cry1AcMod show that they are highly active against both the SfLab and the SfBt populations. The bioassay data reported here show that insects collected from Cry1Fa corn in the Cerrado region were resistant to Cry1Fa suggesting that resistance contributed to field failures of Cry1Fa corn to control S. frugiperda.

  15. Sublethal effects of Cry 1F Bt corn and clothianidin on black cutworm (Lepidoptera: Noctuidae) larval development.

    Science.gov (United States)

    Kullik, Sigrun A; Sears, Mark K; Schaafsma, Arthur W

    2011-04-01

    Black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), is an occasional pest of maize (corn), Zea mays L., that may cause severe stand losses and injury to corn seedlings. The efficacy of the neonicotinoid seed treatment clothianidin at two commercially available rates and their interaction with a transgenic corn hybrid (Bt corn), trait expressing the Bacillus thuringiensis variety aizawai insecticidal toxin Cry 1Fa2, against black cutworm larvae was investigated. Clothianidin at a rate of 25 mg kernel(-1) on Bt corn increased larval mortality and reduced larval weight gains additively. In contrast, weights of larvae fed non-Bt corn seedlings treated with clothianidin at a rate of 25 mg kernel(-1) increased significantly, suggesting either compensatory overconsumption, hormesis, or hormoligosis. Both Bt corn alone and clothianidin at a rate of 125 mg kernel(-1) applied to non-Bt corn seedlings caused increased mortality and reduced larval weight gains. In two field trials, plots planted with Bt corn hybrids consistently had the highest plant populations and yields, regardless of whether they were treated with clothianidin at the lower commercial rate of 25 mg kernel(-1) The use of Bt corn alone or in combination with the low rate of clothianidin (25 mg kernel(-1)) seems suitable as a means of suppressing black cutworm in no-tillage cornfields, although rescue treatments may still be necessary under severe infestations. Clothianidin alone at the low rate of 25 mg kernel(-1) is not recommended for black cutworm control until further studies of its effects on larval physiology and field performance have been completed.

  16. Field-evolved resistance to Bt maize by western corn rootworm: predictions from the laboratory and effects in the field.

    Science.gov (United States)

    Gassmann, Aaron J

    2012-07-01

    Crops engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) provide an effective management tool for many key insect pests. However, pest species have repeatedly demonstrated their ability to adapt to management practices. Results from laboratory selection experiments illustrate the capacity of pest species to evolve Bt resistance. Furthermore, resistance has been documented to Bt sprays in the field and greenhouse, and more recently, by some pests to Bt crops in the field. In 2009, fields were discovered in Iowa (USA) with populations of western corn rootworm, Diabrotica virgifera virgifera LeConte, that had evolved resistance to maize that produces the Bt toxin Cry3Bb1. Fields with resistant insects in 2009 had been planted to Cry3Bb1 maize for at least three consecutive years and as many as 6years. Computer simulation models predicted that the western corn rootworm might evolve resistance to Bt maize in as few as 3years. Laboratory and field data for interactions between western corn rootworm and Bt maize indicate that currently commercialized products are not high-dose events, which increases the risk of resistance evolution because non-recessive resistance traits may enhance survival on Bt maize. Furthermore, genetic analysis of laboratory strains of western corn rootworm has found non-recessive inheritance of resistance. Field studies conducted in two fields identified as harboring Cry3Bb1-resistant western corn rootworm found that survival of western corn rootworm did not differ between Cry3Bb1 maize and non-Bt maize and that root injury to Cry3Bb1 maize was higher than injury to other types of Bt maize or to maize roots protected with a soil insecticide. These first cases of field-evolved resistance to Bt maize by western corn rootworm provide an early warning and point to the need to apply better integrated pest management practices when using Bt maize to manage western corn rootworm. Copyright © 2012 Elsevier

  17. A new artificial diet for western corn rootworm larvae is compatible with and detects resistance to all current Bt toxins

    Science.gov (United States)

    Insect resistance to transgenic crops expressing one or more genes from Bacillus thuringiensis Berliner (Bt) is a growing concern for farmers, regulatory agencies, the seed industry, and researchers alike. Western corn rootworm (Diabrotica virgifera virgifera LeConte) is a pest of corn (Zea mays L.)...

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

    Science.gov (United States)

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

    2016-04-01

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

  19. Apparent digestibility coefficients and consumption of corn silage with and without Bt gene in sheep

    Directory of Open Access Journals (Sweden)

    Camila Memari Trava

    2012-12-01

    Full Text Available Corn silage is the most important preserved food for ruminants. The transgenic corn was inserted into the genetic code Bt gene (Bacillus thuringiensis that expresses a toxic protein to caterpillars pests of maize, reducing production costs. To evaluate the varieties of plant corn silage DKB and AG with or without the Bt gene on the voluntary intake of DM (g/day and apparent digestibility coefficients (CDA of nutrients in sheep, the experiment was conducted at the Institute of Animal Science Nova Odessa-SP. Were used 20 sheep and the experimental design was randomized blocks in scheme factorial type 2x2 (two varieties of plant corn to silage, with the presence or absence of Bt gene, with five animals per treatment. These animals were housed in metabolism cages, with collector and separator feces and urine for 21 days, comprising 8 days for diet adaptation and 7 days for determination of intake, followed by 6 days of collection of feces, to measure DMI (g/day, CDA DM, CP and NDF. Samples of feed offered, leftovers and feces were identified and placed in a circulating air oven maintained at 55°C to constant weight. The analyses were performed in Bromatological Analysis Laboratory of the Institute of Animal Science. To CTMS (g/day was interaction effect (p<0.05 than in the variety AG (779.36 was greater than DKB (637.52, because the DM content of the sheet AG (31.09 was superior to DKB (29.17. The AG (779.36 was higher than your counterpart isogenic without the gene (575.15 p<0.05. The DKB without the gene (637.52 did not differ (p>0.05 from your counterpart DKBBt with the gene (590.78. The lowest total DM intake in g/day was observed for varieties with Bt gene insertion (genetically modified organism - GMO and a possible explanation is the higher value of NDF in the silages of variety with the Bt gene in relation to their isogenic counterparts without the gene. The CDA, DM and NDF no had interaction effect between varieties factors and GMO (p>0

  20. Effect of MON810 Bt field corn on Helicoverpa zea (Lepidoptera: Noctuidae) cannibalism and its implications to resistance development.

    Science.gov (United States)

    Horner, T A; Dively, G P

    2003-06-01

    Pairs of Helicoverpa zea (Boddie) larvae reared on diet-incorporated MON810 transgenic leaf tissue of field corn (Zea mays L.) were observed in the laboratory to characterize effects of sublethal levels of Bacillus thuringiensis variety kurstaki (Bt) Cry1Ab endotoxins on cannibalistic behavior and mortality. Feeding on sublethal levels of Bt corn reduced the frequency of cannibalistic behaviors exhibited by H. zea when uneven instars were paired together. Exposure to the Bt endotoxin had no significant effect on when cannibalistic mortality occurred or the level of mortality as a result of cannibalism. Assuming that H. zea larvae reared on nonBt corn tissue behaved in a similar way that resistant larvae would if feeding on Bt tissue, sublethal effects of Cry1Ab intoxication may reduce the chances of successful cannibalism by susceptible larvae and thus play a disproportionate role in the survival of multiple ear infestations. Furthermore, cannibalistic encounters could result in partially resistant larvae feeding on nontoxic food, thus temporarily providing an escape from exposure to the Bt endotoxin. These behavior alterations could increase the selective differential between susceptible individuals and those carrying resistance genes.

  1. Postcommercialization monitoring of the long-term impact of Bt corn on non-target arthropod communities in commercial farms and adjacent riparian areas in the Philippines.

    Science.gov (United States)

    Alcantara, Edwin P

    2012-10-01

    A 4-yr on-farm study was conducted in the Philippines between 2006 and 2009 to determine if there are any long-term impacts of Bt corn on the arthropod community on commercial farms and in adjacent riparian areas. Arthropod counts were gathered by visual inspection of corn plants in three pairs of commercial farms and by sweep sampling in riparian sites close by. Sampling showed that species composition between Bt and non-Bt corn and between riparian areas adjacent to Bt or non-Bt corn were similar. Principal response curves and analysis of variance showed that there were no adverse effects of Bt corn on the abundance of natural enemies either in crops or adjacent riparian sites. The frequently observed natural enemies in Bt corn were the predatory coccinellid beetle, Micraspis discolor (F.) and spiders (Araneae). Arthropod diversity was similar 1) in Bt- and non-Bt corn and 2) the adjacent riparian areas. Taken together, the two parts of this study show that Bt corn does not have any long-term adverse effect on arthropod communities in corn (Zea mays L.) or in adjacent riparian ecosystems. The methods and results described in this study will be useful to Philippine government regulators in making recommendations and policy guidelines related to monitoring for environmental effects of transgenic crops. The current study did not attempt to demonstrate the direct exposure of arthropods in riparian sites to transgenic Cry1Ab protein that might come from adjacent Bt corn fields; that would require different experimental methods but the current study suggests such effects are unlikely.

  2. The effect of Bt-corn on soil invertebrates, soil microbial community and decomposition rates of corn post-harvest residues under field and laboratory conditions

    Czech Academy of Sciences Publication Activity Database

    Frouz, Jan; Elhottová, Dana; Helingerová, M.; Kocourek, F.

    2008-01-01

    Roč. 32, č. 4 (2008), s. 645-655 ISSN 1044-0046 Institutional research plan: CEZ:AV0Z60660521 Keywords : Bt corn * soil biology * decomposition Subject RIV: EH - Ecology, Behaviour Impact factor: 0.274, year: 2008

  3. Carbon isotope ratios document that the elytra of western corn rootworm (Coleoptera: Chrysomelidae) reflects adult versus larval feeding and later instar larvae prefer Bt corn to alternate hosts.

    Science.gov (United States)

    Hiltpold, Ivan; Adamczyk, John J; Higdon, Matthew L; Clark, Thomas L; Ellersieck, Mark R; Hibbard, Bruce E

    2014-06-01

    In much of the Corn Belt and parts of Europe, the western corn rootworm, Diabrotica virgifera virgifera LeConte, is the most important insect pest of maize. The need for additional basic knowledge of this pest has been highlighted while developing resistance management plans for insecticidal genetically modified crops. This study evaluated the possibility of tracking feeding habits of western corn rootworm larvae using stable carbon isotope signatures. Plants accumulate different ratios of (13)C:(12)C isotopes, usually expressed as δ(13)C, according to whether they use the C3 or C4 photosynthetic pathway. Herbivore biomass is expected to reflect the δ(13)C of the food they eat. For the current experiment, western corn rootworm larvae were grown on different species of plants exhibiting different δ(13)C values. The δ(13)C values were then measured in elytra of emerged beetles. When beetles were unfed, biomass reflected larval feeding. When beetles were fed for 31 d postemergence, δ(13)C values of elytra almost exclusively reflected adult feeding. These results suggest the use of caution in the interpretation of δ(13)C data aiming to document larval diet history when adult feeding history is unknown. The technique was also used to evaluate western corn rootworm larval choice between alternate hosts and maize with and without genetically modified (Bt) traits aimed at their control. Propensity for feeding on alternate hosts versus maize was biased toward feeding on maize regardless whether the maize had Bt or not, suggesting western corn rootworm larvae were not repelled by Bt. These data will be helpful for regulators in interpreting western corn rootworm feeding data on Bt maize.

  4. INSECTICIDAL TOXIN FROM BACILLUS THURINGIENSIS IS RELEASED FROM ROOTS OF TRANSGENIC BT CORN IN VITRO AND IN SITU. (R826107)

    Science.gov (United States)

    AbstractThe insecticidal toxin encoded by the cry1Ab gene from Bacillus thuringiensis was released in root exudates from transgenic Bt corn during 40 days of growth in soil amended to 0, 3, 6, 9, or 12% (v/v) with montmorillonite or kaolinite in a...

  5. Characterization of Asian Corn Borer Resistance to Bt Toxin Cry1Ie

    Directory of Open Access Journals (Sweden)

    Yueqin Wang

    2017-06-01

    Full Text Available A strain of the Asian corn borer (ACB, Ostrinia furnacalis (Guenée, has evolved >800-fold resistance to Cry1Ie (ACB-IeR after 49 generations of selection. The inheritance pattern of resistance to Cry1Ie in ACB-IeR strain and its cross-resistance to other Bt toxins were determined through bioassay by exposing neonates from genetic-crosses to toxins incorporated into the diet. The response of progenies from reciprocal F1 crosses were similar (LC50s: 76.07 vs. 74.32 μg/g, which suggested the resistance was autosomal. The effective dominance (h decreased as concentration of Cry1Ie increased. h was nearly recessive or incompletely recessive on Cry1Ie maize leaf tissue (h = 0.02, but nearly dominant or incompletely dominant (h = 0.98 on Cry1Ie maize silk. Bioassay of the backcross suggested that the resistance was controlled by more than one locus. In addition, the resistant strain did not perform cross-resistance to Cry1Ab (0.8-fold, Cry1Ac (0.8-fold, Cry1F (0.9-fold, and Cry1Ah (1.0-fold. The present study not only offers the manifestation for resistance management, but also recommends that Cry1Ie will be an appropriate candidate for expression with Cry1Ab, Cry1Ac, Cry1F, or Cry1Ah for the development of Bt maize.

  6. Characterization of Asian Corn Borer Resistance to Bt Toxin Cry1Ie.

    Science.gov (United States)

    Wang, Yueqin; Yang, Jing; Quan, Yudong; Wang, Zhenying; Cai, Wanzhi; He, Kanglai

    2017-06-07

    A strain of the Asian corn borer (ACB), Ostrinia furnacalis (Guenée), has evolved >800-fold resistance to Cry1Ie (ACB-IeR) after 49 generations of selection. The inheritance pattern of resistance to Cry1Ie in ACB-IeR strain and its cross-resistance to other Bt toxins were determined through bioassay by exposing neonates from genetic-crosses to toxins incorporated into the diet. The response of progenies from reciprocal F₁ crosses were similar (LC 50 s: 76.07 vs. 74.32 μg/g), which suggested the resistance was autosomal. The effective dominance ( h ) decreased as concentration of Cry1Ie increased. h was nearly recessive or incompletely recessive on Cry1Ie maize leaf tissue ( h = 0.02), but nearly dominant or incompletely dominant ( h = 0.98) on Cry1Ie maize silk. Bioassay of the backcross suggested that the resistance was controlled by more than one locus. In addition, the resistant strain did not perform cross-resistance to Cry1Ab (0.8-fold), Cry1Ac (0.8-fold), Cry1F (0.9-fold), and Cry1Ah (1.0-fold). The present study not only offers the manifestation for resistance management, but also recommends that Cry1Ie will be an appropriate candidate for expression with Cry1Ab, Cry1Ac, Cry1F, or Cry1Ah for the development of Bt maize.

  7. Mechanism and DNA-based detection of field-evolved resistance to transgenic Bt corn in fall armyworm (Spodoptera frugiperda).

    Science.gov (United States)

    Banerjee, Rahul; Hasler, James; Meagher, Robert; Nagoshi, Rodney; Hietala, Lucas; Huang, Fangneng; Narva, Kenneth; Jurat-Fuentes, Juan Luis

    2017-09-07

    Evolution of resistance threatens sustainability of transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). The fall armyworm (Spodoptera frugiperda) is a devastating pest of corn in the Western Hemisphere initially controlled by transgenic Bt corn producing the Cry1Fa insecticidal protein (event TC1507). However field-evolved resistance to TC1507 was observed in Puerto Rico in 2007 and has subsequently been reported in a number of locations in North and South America. Early studies on Puerto Rico fall armyworm populations found that the resistance phenotype was associated with reduced expression of alkaline phosphatase. However, in this work we show that field-evolved resistance to Cry1Fa Bt corn in Puerto Rico is closely linked to a mutation in an ATP Binding Cassette subfamily C2 (ABCC2) gene that functions as a Cry1Fa receptor in susceptible insects. Furthermore, we report a DNA-based genotyping test used to demonstrate the presence of the resistant (SfABCC2mut) allele in Puerto Rico populations in 2007, coincident with the first reports of damage to TC1507 corn. These DNA-based field screening data provide strong evidence that resistance to TC1507 in fall armyworm maps to the SfABCC2 gene and provides a useful molecular marker for detecting the SfABCC2mut allele in resistant fall armyworm.

  8. Ingestion of Bt corn pollen containing Cry1Ab/2Aj or Cry1Ac does not harm Propylea japonica larvae.

    Science.gov (United States)

    Liu, Yanmin; Liu, Qingsong; Wang, Yanan; Chen, Xiuping; Song, Xinyuan; Romeis, Jörg; Li, Yunhe; Peng, Yufa

    2016-03-23

    Propylea japonica (Thunberg) (Coleoptera: Coccinellidae) is a prevalent pollen consumer in corn fields and is therefore exposed to insecticidal proteins contained in the pollen of insect-resistant transgenic corn cultivars expressing Cry proteins derived from Bacillus thuringiensis (Bt). In the present study, the potential effect of Cry1Ab/2Aj- or Cry1Ac-containing transgenic Bt corn pollen on the fitness of P. japonica larvae was evaluated. The results show that the larval developmental time was significantly shorter when P. japonica larvae were fed pollen from Bt corn cultivars rather than control pollen but that pupation rate, eclosion rate, and adult fresh weight were not significantly affected. In the feeding experiments, the stability of the Cry proteins in the food sources was confirmed. When Bt corn pollen passed through the gut of P. japonica, 23% of Cry1Ab/2Aj was digested. The results demonstrate that consumption of Bt corn pollen containing Cry1Ab/2Aj or Cry1Ac has no detrimental effect on P. japonica larvae; the shortened developmental time of larvae that consumed these proteins was likely attributable to unknown differences in the nutritional composition between the Bt-transgenic and control corn pollen.

  9. Is the Cry1Ab protein from Bacillus thuringiensis (Bt) taken up by plants from soils previously planted with Bt corn and by carrot from hydroponic culture?

    Science.gov (United States)

    Icoz, I; Andow, D; Zwahlen, C; Stotzky, G

    2009-07-01

    The uptake of the insecticidal Cry1Ab protein from Bacillus thuringiensis (Bt) by various crops from soils on which Bt corn had previously grown was determined. In 2005, the Cry1Ab protein was detected by Western blot in tissues (leaves plus stems) of basil, carrot, kale, lettuce, okra, parsnip, radish, snap bean, and soybean but not in tissues of beet and spinach and was estimated by enzyme-linked immunosorbent assay (ELISA) to be 0.05 +/- 0.003 ng g(-1) of fresh plant tissue in basil, 0.02 +/- 0.014 ng g(-1) in okra, and 0.34 +/- 0.176 ng g(-1) in snap bean. However, the protein was not detected by ELISA in carrot, kale, lettuce, parsnip, radish, and soybean or in the soils by Western blot. In 2006, the Cry1Ab protein was detected by Western blot in tissues of basil, carrot, kale, radish, snap bean, and soybean from soils on which Bt corn had been grown the previous year and was estimated by ELISA to be 0.02 +/- 0.014 ng g(-1) of fresh plant tissue in basil, 0.19 +/- 0.060 ng g(-1) in carrot, 0.05 +/- 0.018 ng g(-1) in kale, 0.04 +/- 0.022 ng g(-1) in radish, 0.53 +/- 0.170 ng g(-1) in snap bean, and 0.15 +/- 0.071 ng g(-1) in soybean. The Cry1Ab protein was also detected by Western blot in tissues of basil, carrot, kale, radish, and snap bean but not of soybean grown in soil on which Bt corn had not been grown since 2002; the concentration was estimated by ELISA to be 0.03 +/- 0.021 ng g(-1) in basil, 0.02 +/- 0.008 ng g(-1) in carrot, 0.04 +/- 0.017 ng g(-1) in kale, 0.02 +/- 0.012 ng g(-1) in radish, 0.05 +/- 0.004 ng g(-1) in snap bean, and 0.09 +/- 0.015 ng g(-1) in soybean. The protein was detected by Western blot in 2006 in most soils on which Bt corn had or had not been grown since 2002. The Cry1Ab protein was detected by Western blot in leaves plus stems and in roots of carrot after 56 days of growth in sterile hydroponic culture to which purified Cry1Ab protein had been added and was estimated by ELISA to be 0.08 +/- 0.021 and 0.60 +/- 0.148 ng g(-1) of

  10. Yield Losses in Transgenic Cry1Ab and Non-Bt Corn as Assessed Using a Crop-Life-Table Approach.

    Science.gov (United States)

    Silva, Gerson A; Picanço, Marcelo C; Ferreira, Lino R; Ferreira, Dalton O; Farias, Elizeu S; Souza, Thadeu C; Rodrigues-Silva, Nilson; Pereira, Eliseu José G

    2018-02-09

    In this study, we constructed crop life tables for Bacillus thuringiensis Berliner (Bt) Cry1Ab and non-Bt corn hybrids, in which yield-loss factors and abundance of predaceous arthropods were recorded during 2 yr at two locations. Corn kernel/grain was the yield component that had the heaviest losses and that determined the overall yield loss in the corn hybrids across years and locations. Yield losses in both corn hybrids were primarily caused by kernel-destroying insects. Helicoverpa zea (Boddie) and Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) were the key loss factors at one location, while at the other, the key loss factor was the silk fly larvae, Euxesta spp. (Diptera: Ulidiidae). Although the realized yield of corn grains was not different (P > 0.05) between Cry1Ab and non-Bt corn hybrids, the Bt corn hybrid reduced (P corn fields. Various species of natural enemies were recorded, particularly the earwig Doru luteipes (Scudder) (Dermaptera: Forficulidae), which was the most abundant and frequent predaceous insect. These results indicate that integration of pest management practices should be pursued to effectively minimize losses by kernel-destroying insects during corn reproductive stages when growing non-Bt or certain low-dose Bt corn cultivars for fall armyworm and corn earworm, such as those producing Cry1Ab or other Cry toxins. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Resistance evolution to Bt crops: predispersal mating of European corn borers.

    Directory of Open Access Journals (Sweden)

    Ambroise Dalecky

    2006-06-01

    Full Text Available Over the past decade, the high-dose refuge (HDR strategy, aimed at delaying the evolution of pest resistance to Bacillus thuringiensis (Bt toxins produced by transgenic crops, became mandatory in the United States and is being discussed for Europe. However, precopulatory dispersal and the mating rate between resident and immigrant individuals, two features influencing the efficiency of this strategy, have seldom been quantified in pests targeted by these toxins. We combined mark-recapture and biogeochemical marking over three breeding seasons to quantify these features directly in natural populations of Ostrinia nubilalis, a major lepidopteran corn pest. At the local scale, resident females mated regardless of males having dispersed beforehand or not, as assumed in the HDR strategy. Accordingly, 0-67% of resident females mating before dispersal did so with resident males, this percentage depending on the local proportion of resident males (0% to 67.2%. However, resident males rarely mated with immigrant females (which mostly arrived mated, the fraction of females mating before dispersal was variable and sometimes substantial (4.8% to 56.8%, and there was no evidence for male premating dispersal being higher. Hence, O. nubilalis probably mates at a more restricted spatial scale than previously assumed, a feature that may decrease the efficiency of the HDR strategy under certain circumstances, depending for example on crop rotation practices.

  12. A comparison of Bt transgene, hybrid background, water stress, and insect stress effects on corn leaf and ear injury and subsequent yield.

    Science.gov (United States)

    Brewer, Michael J; Odvody, Gary N; Anderson, Darwin J; Remmers, Jeffrey C

    2014-06-01

    Experimentally manipulated water and insect stresses were applied to field-grown corn with different Bacillus thuringiensis (Bt) transgenes and no Bt transgenes, and different nontransgenic hybrid backgrounds (2011 and 2012, Corpus Christi, TX). Differences in leaf injury, ear injury, and yield were detected among experimental factors and their interactions. Under high and low water stress, injury from noctuid larvae (Lepidoptera: Noctuidae) on leaves during vegetative growth (primarily from fall armyworm, Spodoptera frugiperda J.E. Smith) and on developing ears (primarily from corn earworm, Helicoverpa zea [Boddie]) was lowest on more recent releases of Bt hybrids (newer Bt hybrids) expressing Cry1A.105+Cry2Ab2 and Cry 3Bb1, compared with earlier Bt hybrids (older Bt hybrids) expressing Cry1Ab and Cry3Bb1 and non-Bt hybrids. High water stress led to increased leaf injury under substantial fall armyworm feeding pressure in 2011 (as high as 8.7 on a 1-9 scale of increasing injury). In contrast, ear injury by corn earworm (as high as 20 cm(2) of surface area of injury) was greater in low water stress conditions. Six hybrid backgrounds did not influence leaf injury, while ear injury differences across hybrid backgrounds were detected for non-Bt and older Bt hybrid versions. While newer Bt hybrids expressing Cry1A.105+Cry2Ab2 and Cry 3Bb1 had consistent low leaf injury and high yield and low but less consistent ear injury across six hybrid backgrounds, water stress was a key factor that influenced yield. Bt transgenes played a more variable and lesser role when interacting with water stress to affect yield. These results exemplify the interplay of water and insect stress with plant injury and yield, their interactions with Bt transgenes, and the importance of these interactions in considering strategies for Bt transgene use where water stress is common.

  13. Susceptibility of field populations of the fall armyworm (Lepidoptera: Noctuidae) from Florida and Puerto Rico to purified Cry1F protein and corn leaf tissue containing single and pyramided Bt genes

    Science.gov (United States)

    Larval survival of Cry1F-susceptible (FL), -resistant (PR and Cry1F-RR), and -heterozygous (FL x PR and Cry1F-RS) populations of the fall armyworm, Spodoptera frugiperda (J.E. Smith) to purified Cry1F protein and corn leaf tissue of seven Bacillus thuringiensis (Bt) corn hybrids and five non-Bt corn...

  14. Lepidoptera (Crambidae, Noctuidae, and Pyralidae) Injury to Corn Containing Single and Pyramided Bt Traits, and Blended or Block Refuge, in the Southern United States.

    Science.gov (United States)

    Reisig, D D; Akin, D S; All, J N; Bessin, R T; Brewer, M J; Buntin, D G; Catchot, A L; Cook, D; Flanders, K L; Huang, F-N; Johnson, D W; Leonard, B R; Mcleod, P J; Porter, R P; Reay-Jones, F P F; Tindall, K V; Stewart, S D; Troxclair, N N; Youngman, R R; Rice, M E

    2015-02-01

    Fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae); corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae); southwestern corn borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae); sugarcane borer, Diatraea saccharalis F. (Lepidoptera: Crambidae); and lesser cornstalk borer, Elasmopalpus lignosellus Zeller (Lepidoptera: Pyralidae), are lepidopteran pests of corn, Zea mays L., in the southern United States. Blended refuge for transgenic plants expressing the insecticidal protein derivative from Bacillus thuringiensis (Bt) has recently been approved as an alternative resistance management strategy in the northern United States. We conducted a two-year study with 39 experiments across 12 states in the southern United States to evaluate plant injury from these five species of Lepidoptera to corn expressing Cry1F and Cry1Ab, as both single and pyramided traits, a pyramid of Cry1Ab×Vip3Aa20, and a pyramid of Cry1F×Cry1Ab plus non-Bt in a blended refuge. Leaf injury and kernel damage from corn earworm and fall armyworm, and stalking tunneling by southwestern corn borer, were similar in Cry1F×Cry1Ab plants compared with the Cry1F×Cry1Ab plus non-Bt blended refuge averaged across five-plant clusters. When measured on an individual plant basis, leaf injury, kernel damage, stalk tunneling (southwestern corn borer), and dead or injured plants (lesser cornstalk borer) were greater in the blended non-Bt refuge plants compared to Cry1F×Cry1Ab plants in the non-Bt and pyramided Cry1F×Cry1Ab blended refuge treatment. When non-Bt blended refuge plants were compared to a structured refuge of non-Bt plants, no significant difference was detected in leaf injury, kernel damage, or stalk tunneling (southwestern corn borer). Plant stands in the non-Bt and pyramided Cry1F×Cry1Ab blended refuge treatment had more stalk tunneling from sugarcane borer and plant death from lesser cornstalk borer compared to a pyramided Cry1F×Cry1Ab structured refuge

  15. Genetically modified feeds in animal nutrition. 1st communication: Bacillus thuringiensis (Bt) corn in poultry, pig and ruminant nutrition.

    Science.gov (United States)

    Aulrich, K; Böhme, H; Daenicke, R; Halle, I; Flachowsky, G

    2001-01-01

    During the last few years, animal nutrition has been confronted with genetically modified organisms (GMO), and their significance will increase in the future. The study presents investigations on the substantial equivalence of the transgenic Bt (Bacillus thuringiensis) corn and the corresponding nontransgenic hybrid Cesar and parameters of nutrition physiology such as digestibility and energy content for poultry, pigs and ruminants. The results of the analysed corn samples as well as of the silage samples illustrated substantial equivalence in all investigated ingredients, such as crude nutrients, amino acids, fatty acids, minerals and non-starch polysaccharides. The results of the experiments using poultry, pigs, wethers and fattening bulls were not influenced by the genetic modification of corn. The determined values for the digestibilities and the energy contents for poultry, pigs and wethers were not affected by the used corn variety. Neither the examined parameters of the fattening experiments with bulls nor the slaughter results showed any significant differences between the bulls fed on silages made from the nontransgenic or transgenic corn.

  16. In situ degrability of dry matter of sheep fed with corn silage with or without Bt gene

    Directory of Open Access Journals (Sweden)

    Camila Memari Trava

    2012-12-01

    Full Text Available Silage corn is a food widely used, composing the bulk of feed for ruminants, because its present high nutritional value. Since the release by CNTBio seeds of modified genetically corn, many of it began to use transgenic silage corn, which was inserted into genetic code the Bt (Bacillus thuringiensis gene that expresses a toxic protein to caterpillar pests of corn, so occurs the reduction of production costs and pesticide use. Due to rapid expansion of transgenic maize and your wide use in animal feed by producers, the aim of this study was to evaluate the degrability in situ in animal rumen, in order to estimate the nutritional value of silage corn with and without the Bt gene. The experiment was conducted at the Institute of Animal Science Nova Odessa-SP. Were used four rumen fistulated sheep housed in individual pens for 56 days, including four periods. The animals were fed with silage with two varieties of plant corn to silage - DKB and AG, and their isogenic counterparts with the Bt gene, comprising four treatments. The degradability determination of dry matter (DM digestibility of silage corn treatments was determined by means of nylon bag in situ. After removal, the bags were washed and incubated, then placed in forced-circulation at 55°C to constant weight to determine the DM concentration. Data from in situ degradation of DM was adjusted in the mathematical model proposed by Ørskov and McDonald (1979. For the degradability of DM, the fraction “a” showed the interaction (p <0.05, where the variety DKB do not showed difference (p> 0.05 for the gene insertion. For AG, showed a slight decrease (p <0.05 when compared to its isogenic counterpart with the gene (35.68% and 37.85% respectively, means that the Bt gene reduced the solubility of DM of this fraction for AG range. The fact of the variety AG with and without the gene have suffered lower solubility of DM when compared the DKB with and without the gene is due to the fact of being

  17. Impact of Cry3Bb1-expressing Bt maize on adults of the western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Meissle, Michael; Hellmich, Richard L; Romeis, Jörg

    2011-07-01

    Genetically engineered maize producing insecticidal Cry3Bb1 protein from Bacillus thuringiensis (Bt) is protected from root damage by corn rootworm larvae. An examination was made to establish whether western corn rootworm (Diabrotica virgifera virgifera) adults are affected by Cry3Bb1-expressing maize (MON88017) when feeding on above-ground tissue. In laboratory bioassays, adult D. v. virgifera were fed for 7 weeks with silk, leaves or pollen from Bt maize or the corresponding near-isoline. Male, but not female, survival was reduced in the Bt-leaf treatment compared with the control. Female weight was lower when fed Bt maize, and egg production was reduced in the Bt-silk treatment. ELISA measurements demonstrated that beetles feeding on silk were exposed to higher Cry3Bb1 concentrations than beetles collected from Bt-maize fields in the United States. In contrast to silk and pollen, feeding on leaves resulted in high mortality and low fecundity. Females feeding on pollen produced more eggs than on silk. C:N ratios indicated that silk does not provide enough nitrogen for optimal egg production. Direct effects of Cry3Bb1 on adult beetles could explain the observed effects, but varietal differences between Bt and control maize are also possible. The impact of Bt maize on adult populations, however, is likely to be limited. Copyright © 2011 Society of Chemical Industry.

  18. A challenge for the seed mixture refuge strategy in Bt maize: impact of cross-pollination on an ear-feeding pest, corn earworm.

    Directory of Open Access Journals (Sweden)

    Fei Yang

    Full Text Available To counter the threat of insect resistance, Bacillus thuringiensis (Bt maize growers in the U.S. are required to plant structured non-Bt maize refuges. Concerns with refuge compliance led to the introduction of seed mixtures, also called RIB (refuge-in-the-bag, as an alternative approach for implementing refuge for Bt maize products in the U.S. Maize Belt. A major concern in RIB is cross-pollination of maize hybrids that can cause Bt proteins to be present in refuge maize kernels and negatively affect refuge insects. Here we show that a mixed planting of 5% nonBt and 95% Bt maize containing the SmartStax traits expressing Cry1A.105, Cry2Ab2 and Cry1F did not provide an effective refuge for an important above-ground ear-feeding pest, the corn earworm, Helicoverpa zea (Boddie. Cross-pollination in RIB caused a majority (>90% of refuge kernels to express ≥ one Bt protein. The contamination of Bt proteins in the refuge ears reduced neonate-to-adult survivorship of H. zea to only 4.6%, a reduction of 88.1% relative to larvae feeding on ears of pure non-Bt maize plantings. In addition, the limited survivors on refuge ears had lower pupal mass and took longer to develop to adults.

  19. A challenge for the seed mixture refuge strategy in Bt maize: impact of cross-pollination on an ear-feeding pest, corn earworm.

    Science.gov (United States)

    Yang, Fei; Kerns, David L; Head, Graham P; Leonard, B Rogers; Levy, Ronnie; Niu, Ying; Huang, Fangneng

    2014-01-01

    To counter the threat of insect resistance, Bacillus thuringiensis (Bt) maize growers in the U.S. are required to plant structured non-Bt maize refuges. Concerns with refuge compliance led to the introduction of seed mixtures, also called RIB (refuge-in-the-bag), as an alternative approach for implementing refuge for Bt maize products in the U.S. Maize Belt. A major concern in RIB is cross-pollination of maize hybrids that can cause Bt proteins to be present in refuge maize kernels and negatively affect refuge insects. Here we show that a mixed planting of 5% nonBt and 95% Bt maize containing the SmartStax traits expressing Cry1A.105, Cry2Ab2 and Cry1F did not provide an effective refuge for an important above-ground ear-feeding pest, the corn earworm, Helicoverpa zea (Boddie). Cross-pollination in RIB caused a majority (>90%) of refuge kernels to express ≥ one Bt protein. The contamination of Bt proteins in the refuge ears reduced neonate-to-adult survivorship of H. zea to only 4.6%, a reduction of 88.1% relative to larvae feeding on ears of pure non-Bt maize plantings. In addition, the limited survivors on refuge ears had lower pupal mass and took longer to develop to adults.

  20. Ocorrência do ácaro fitófago Catarhinus tricholaenae Keifer (Acari: Diptilomiopidae em cultivares de milho Bt Occurrence of the phytophagous mite Catarhinus tricholaenae Keifer (Acari: Diptilomiopidae on Bt corn cultivars

    Directory of Open Access Journals (Sweden)

    Marcos Antônio Matiello Fadini

    2012-09-01

    Full Text Available O objetivo deste trabalho foi avaliar a ocorrência do microácaro-da-face-inferior-das-folhas-de-milho Catarhinus tricholaenae Keifer (Acari: Diptilomiopidae em cultivares transgênicas de milho, contendo as proteínas Cry1F e Cry 1 A(b e milho não Bt. Durante o período de junho de 2010 a janeiro de 2011, foram coletadas, quinzenalmente, cinco amostras aleatórias de quatro folhas em talhões de milho Bt, contendo a proteína Cry 1F e Cry 1 A(b, e de milho não Bt em áreas experimentais da Embrapa Milho e Sorgo, em Sete Lagoas, MG. As amostras de folhas foram vistoriadas por 15 minutos na região da nervura central, em busca de adultos de C. tricholaenae. Foram registrados 2.930 indivíduos de C. tricholaenae, sendo que 1.114 no milho Bt Cry 1F, 753 em Cry 1 A(b e 1063 indivíduos em folhas das cultivares não Bt. As maiores abundâncias populacionais médias ocorreram nos meses de novembro e dezembro. Os fatores estágio fenológico das plantas e precipitação afetaram positivamente a abundância de C. tricholaenae. A abundância média do período de coleta de C. tricholaenae foi reduzida pela cultivar de milho contendo a proteína Cry 1 A(b. Esse é o primeiro registro de ácaros sobre cultivares de milho transgênico no Brasil.The objective of this study was to evaluate the occurrence of "microácaro-da-face-inferior-das-folhas-de-milho" Catarhinus tricholaenae Keifer (Acari: Diptilomiopidae on transgenic cultivars of corn containing proteins Cry1F and Cry 1 A (b and non-Bt corn. During the period from June 2010 to January 2011 were collected, every two weeks, five random samples of four leaves in plots of Bt corn containing the protein Cry 1F and Cry 1 A (b and non-Bt corn in the experimental area of Embrapa Corn and Sorghum, Sete Lagoas, MG. The leaf samples were examined for 15 minutes in the central region of leaf in search of adult C. tricholaenae. We recorded 2930 individuals of C. tricholaenae, 1114 on Bt Cry 1F, 752 on Cry 1 A

  1. Resistance evolution to the first generation of genetically modified Diabrotica-active Bt-maize events by western corn rootworm: management and monitoring considerations

    Science.gov (United States)

    Western corn rootworm (Diabrotica virgifera virgifera; WCR) is a major coleopteran maize pest in North America and the EU, and has traditionally been managed through crop rotation and broad-spectrum soil insecticides. Genetically modified (GM) Bt-maize offers an additional means of control against W...

  2. Comparison of fumonisin contamination using HPLC and ELISA methods in bt and near-isogenic maize hybrids infested with European corn borer or western bean cutworm.

    Science.gov (United States)

    Bowers, Erin; Hellmich, Richard; Munkvold, Gary

    2014-07-09

    Field trials were conducted from 2007 to 2010 to compare grain fumonisin levels among non-Bt maize hybrids and Bt hybrids with transgenic protection against manual infestations of European corn borer (ECB) and Western bean cutworm (WBC). HPLC and ELISA were used to measure fumonisin levels. Results of the methods were highly correlated, but ELISA estimates were higher. Bt hybrids experienced less insect injury, Fusarium ear rot, and fumonisin contamination compared to non-Bt hybrids. WBC infestation increased fumonisin content compared to natural infestation in non-Bt and hybrids expressing Cry1Ab protein in five of eight possible comparisons; in Cry1F hybrids, WBC did not impact fumonisins. These results indicate that WBC is capable of increasing fumonisin levels in maize. Under WBC infestation, Cry1F mitigated this risk more consistently than Cry1Ab or non-Bt hybrids. Transgenically expressed Bt proteins active against multiple lepidopteran pests can provide broad, consistent reductions in the risk of fumonisin contamination.

  3. Impact of the Bt Corn Proteins Cry34/35Ab1 and Cry3Bb1, Alone or Pyramided, on Western Corn Rootworm (Coleoptera: Chrysomelidae) Beetle Emergence in the Field.

    Science.gov (United States)

    Hitchon, A J; Smith, J L; French, B W; Schaafsma, A W

    2015-08-01

    Western corn rootworm, Diabrotica virgifera virgifera LeConte, is a major pest of corn, Zea mays L. The effect of the Bt proteins Cry34/35Ab1 and Cry3Bb1, alone or pyramided in corn hybrids on D. v. virgifera adult emergence was evaluated in field experiments for 3 yr. Experiments were infested artificially with 2,500 viable D. v. virgifera eggs per row meter of corn. The reduction in beetle emergence compared with non-Bt controls, from Cry34/35Ab1, Cry3Bb1, and the pyramided hybrids ranged from 64.3 to 97.4%, 91.1 to 95.2%, and 98.1 to 99.6%, respectively. The sex ratio of emerged beetles was usually female-biased from the Cry3Bb1 and pyramided treatments, but not from Cry34/35Ab1 treatment alone. Emergence from all Bt hybrids was delayed compared with the control, with the delay longest from the pyramided hybrid. In 2013, three egg infestation levels were tested, with density-dependent mortality observed at 1,250 viable eggs per row meter. The effect of Bt proteins on the emergence timing and sex ratio of D. v. virgifera may impact the suitability of resistance management plans, specifically the effectiveness of the refuge strategy. Susceptible males emerging from refuge might not be synchronized to mate with potentially resistant females emerging later from Bt corn hybrids. © 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.

  4. Resistance evolution to the first generation of genetically modified Diabrotica-active Bt-maize events by western corn rootworm: management and monitoring considerations.

    Science.gov (United States)

    Devos, Yann; Meihls, Lisa N; Kiss, József; Hibbard, Bruce E

    2013-04-01

    Western corn rootworm (Diabrotica virgifera virgifera; WCR) is a major coleopteran maize pest in North America and the EU, and has traditionally been managed through crop rotation and broad-spectrum soil insecticides. Genetically modified Bt-maize offers an additional management tool for WCR and has been valuable in reducing insecticide use and increasing farm income. A concern is that the widespread, repeated, and exclusive deployment of the same Bt-maize transformation event will result in the rapid evolution of resistance in WCR. This publication explores the potential of WCR to evolve resistance to plant-produced Bt-toxins from the first generation of Diabrotica-active Bt-maize events (MON 863 and MON 88017, DAS-59122-7 and MIR604), and whether currently implemented risk management strategies to delay and monitor resistance evolution are appropriate. In twelve of the twelve artificial selection experiments reported, resistant WCR populations were yielded rapidly. Field-selected resistance of WCR to Cry3Bb1 is documented in some US maize growing areas, where an increasing number of cases of unexpected damage of WCR larvae to Bt-maize MON 88017 has been reported. Currently implemented insect resistance management measures for Bt-crops usually rely on the high dose/refuge (HDR) strategy. Evidence (including laboratory, greenhouse and field data) indicates that several conditions contributing to the success of the HDR strategy may not be met for the first generation of Bt-maize events and WCR: (1) the Bt-toxins are expressed heterogeneously at a low-to-moderate dose in roots; (2) resistance alleles may be present at a higher frequency than initially assumed; (3) WCR may mate in a non-random manner; (4) resistance traits could have non-recessive inheritance; and (5) fitness costs may not necessarily be associated with resistance evolution. However, caution must be exercised when extrapolating laboratory and greenhouse results to field conditions. Model predictions

  5. A new genus and species of Eucoilinae (Hymenoptera, Cynipoidea, Figitidae parasitoid of Euxesta eluta Loew (Diptera, Otitidae attacked Bt sweet corn in Argentina

    Directory of Open Access Journals (Sweden)

    Fabiana E. Gallardo

    2017-02-01

    Full Text Available Euxestophaga Gallardo, a new genus of Eucoilinae (Hymenoptera, Cynipoidea, Figitidae and Euxestophaga argentinensis Gallardo, sp. n. from Argentina, are described and illustrated. This new genus belongs to the Ganaspini and morphologically resembles Epicoela Borgmeier and Striatovertex Schick, Forshage and Nordlander. A key to differentiate these genera is given. Specimens were reared from pupae of Euxesta eluta Loew (Diptera: Otitidae, attacked Bt sweet corn in Santa Fe province and other in Tucumán province (Argentina.

  6. Impact of Lepidoptera (Crambidae, Noctuidae, and Pyralidae) Pests on Corn Containing Pyramided Bt Traits and a Blended Refuge in the Southern United States.

    Science.gov (United States)

    Reay-Jones, F P F; Bessin, R T; Brewer, M J; Buntin, D G; Catchot, A L; Cook, D R; Flanders, K L; Kerns, D L; Porter, R P; Reisig, D D; Stewart, S D; Rice, M E

    2016-08-01

    Blended refuge for transgenic plants expressing Bacillus thuringiensis (Bt) toxins has been approved in the northern United States as a resistance management strategy alternative to a structured refuge. A three-year study (2012-2014) was conducted with 54 trials across nine states in the southern United States to evaluate plant injury from lepidopteran pests of corn and yield in a corn hybrid expressing Cry1F × Cry1Ab × Vip3Aa20 (Pioneer Brand Optimum Leptra) planted as a pure stand and in refuge blends of 5, 10, and 20% in both early and late plantings. Injury by corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), and fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), was generally proportional to the percentage of non-Bt corn within each refuge blend. Across locations, ear injury in plots with 100% Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) corn ranged from no injury to a maximum of 0.42 cm(2) per ear in Mississippi in 2013. Leaf injury ratings in 100% non-Bt plots in early and late planted trials in 2014 were 86- and 70-fold greater than in 100% Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) plots. Plants in plots with blended refuges had significantly greater leaf injury in 2012 (5, 10, and 20% refuge blends), in the early-planted corn in 2013 (10 and 20% only), and in both early- and late-planted corn in 2014 (20% only) as compared with leaf injury in a pure stand of Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) seen during these years. Corn ears in plots with blended refuges also had significantly greater area of kernels injured in 2012 (5, 10, and 20%), in early- and late-planted corn in 2013 (5, 10, and 20%), and in early (10 and 20% only)- and late-planted corn (5, 10, and 20%) in 2014 as compared with ear injury in a pure stand of Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) seen during these years. Infestations of southwestern corn borer, Diatraea grandiosella Dyar (Lepidoptera

  7. Framework to Delay Corn Rootworm Resistance

    Science.gov (United States)

    This proposed framework is intended to delay the corn rootworm pest becoming resistant to corn genetically engineered to produce Bt proteins, which kill corn rootworms but do not affect people or wildlife. It includes requirements on Bt corn manufacturers.

  8. Larval development of Spodoptera eridania and Spodoptera frugiperda fed on fresh ear of field corn expressing the Bt proteins (Cry1F and Cry1F + Cry1A.105 + Cry2Ab2

    Directory of Open Access Journals (Sweden)

    Orcial Ceolin Bortolotto

    Full Text Available ABSTRACT: The objective of this study was to evaluate extent of larval period, larval survival (%, food consumption, and pupal biomass of Spodoptera eridania and Spodoptera frugiperda (Lepidoptera: Noctuidae fed on fresh ears of field corn expressing Bt proteins (Cry1F and Cry1F+Cry1A.105+Cry2Ab2. Larvae of Spodoptera spp. survived less than two days when they consumed Bt corncobs and showed 100% mortality. Spodoptera eridania reared on non-Bt corn cobs showed higher larval development (21.6 days than S. frugiperda (18.4 days and lower viability (56.4% and 80.2% for S. eridania and S. frugiperda , respectively. A higher amount of corn grains was consumed by S. eridania (5.4g than by S. frugiperda (3.9g. In summary, this study demonstrated that the toxins Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 expressed in fresh corn cobs contributed to protect ears of corn against S. frugiperda and the non-target pest S. eridania . However, itis important to monitor non-Bt cornfields because of the potential of both species to cause damage to ear sof corn.

  9. [Corn.

    Science.gov (United States)

    Iowa History for Young People, 1993

    1993-01-01

    This theme issue focuses on corn. Iowa is the number one corn producing state in the United States. The featured articles in the issue concern, among other topics, Iowa children who live on farms, facts and statistics about corn, the Mesquakie Indians and corn shelling, corn hybrids, a short story, and the corn palaces of Sioux City. Activities,…

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

    Science.gov (United States)

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

    2015-08-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

  12. Efficacy of Bt maize producing the Cry1Ac protein against two important pests of corn in China.

    Science.gov (United States)

    Chen, Hong-Xing; Yang, Rui; Yang, Wang; Zhang, Liu; Camara, Ibrahima; Dong, Xue-Hui; Liu, Yi -Qing; Shi, Wang-Peng

    2016-11-01

    Ostrinia furnacalis (Guenée) and Helicoverpa armigera (Hübner) are the most important pests of maize in China. A laboratory study and a 2-year field study on the efficacy of transgenic maize expressing the Cry1Ac protein BT38 against O. furnacalis and H. armigera were performed. We found that the husks, kernels, and silks of BT38 showed significant efficacy against larvae of O. furnacalis and H. armigera. In the field, when neonate larvae of O. furnacalis and H. armigera were on plants at different growth stages and when levels of leaf-damage or number of damaged silks were used to score efficacy, we found that BT38 showed significant insecticidal efficacy against O. furnacalis and H. armigera, but the non-Bt maize did not show significant efficacy against either pest. These results suggest that the insecticidal efficacy of Bt maize expressing the Cry1Ac protein could be useful in the integrated pest management of these key maize pests.

  13. Larval mortality and development for rotation-resistant and rotation-susceptible populations of the western corn rootworm on Bt corn

    Science.gov (United States)

    The western corn rootworm, Diabrotica virgifera virgifera LeConte, is one of the most economically important insect pests threatening the production of corn, Zea mays (L.), in the United States. Throughout its history, this insect has displayed considerable adaptability by overcoming a variety of pe...

  14. Transgenic Bt corn varietal resistance against the Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Cramibidae) and implications to sugarcane

    Science.gov (United States)

    The Mexican rice borer, Eoreuma loftini (Dyar), attacks crops including corn, Zea mays L.; rice, Oryza sativa L.; sorghum, Sorghum bicolor (L.) Moench; and sugarcane, Saccharum spp., but strongly resistant varieties of any kind, native or otherwise, have not been identified. A field plot corn varie...

  15. Efficacy of pyramided Bt proteins Cry1F, Cry1A.105, and cry2Ab2 expressed in Smartstax corn hybrids against lepidopteran insect pests in the northern United States.

    Science.gov (United States)

    Rule, D M; Nolting, S P; Prasifka, P L; Storer, N P; Hopkins, B W; Scherder, E F; Siebert, M W; Hendrix, W H

    2014-02-01

    Commercial field corn (Zea mays L.) hybrids transformed to express some or all of the lepidopteran insect-resistant traits present in SmartStax corn hybrids were evaluated for insecticidal efficacy against a wide range oflepidopteran corn pests common to the northern United States, during 2008 to 2011 at locations in 15 states. SmartStax hybrids contain a pyramid of two Bacillus thuringiensis (Bt) derived events for lepidopteran control: event TC1507 expressing Cry1F protein and MON 89034 expressing CrylA.105 + Cry2Ab2. These studies focused on characterization of the relative efficacy of each event when expressed alone or in combination, and compared with non-Bt hybrid. Corn hybrids containing pyramided insecticidal proteins Cry1F + Cry1A.105 + Cry2Ab2 (SmartStax) consistently showed reduced plant feeding damage by a wide range of lepidopteran larvae compared with single event and non-Bt hybrids. Corn hybrids expressing TC1507 or MON 89034 as single or pyramided events were consistently efficacious against Ostrinia nubilalis (Hübner). SmartStax hybrids had less injury from Agrotis ipsilon (Hufnagel) and Striacosta albicosta (Smith) than corn hybrids containing only event MON 89034 but were not more efficacious than single event TC1507 hybrids. Corn hybrids with event MON 89034 provided better control of Helicoverpa zea (Boddie), than event TC1507 alone. Spodoptera frugiperda (J.E. Smith) efficacy was higher for hybrids with pyramid events and single events compared with the non-Bt hybrids. The spectra of activity of events TC1507 and MON 89034 differed. The combination of TC1507 + MON 89034 provided redundant control of some pests where the spectra overlapped and thereby are expected to confer a resistance management benefit.

  16. Survival of Corn Earworm (Lepidoptera: Noctuidae) on Bt Maize and Cross-Pollinated Refuge Ears From Seed Blends.

    Science.gov (United States)

    Crespo, André Luiz Barreto; Alves, Analiza Piovesan; Wang, Yiwei; Hong, Bonnie; Flexner, John Lindsey; Catchot, Angus; Buntin, David; Cook, Donald

    2016-02-01

    Refuge is mandated in the United States where genetically modified maize (Zea mays L.) expressing insecticidal proteins derived from Bacillus thuringiensis Berliner (Bt) are cultivated. Currently, refuge is deployed in different ways including blocks, field strips, or seed blends containing Bt and non-Bt maize. Seed blends provide practical advantages for refuge implementation. However, concerns related to the movement of insect larvae, potential differential survival of heterozygous resistant larvae, reduction in insect production, and cross-pollination of ears resulting in sublethal selection, have delayed seed blend use for Lepidoptera in the southern United States, where maize plantings are used as refuge for Helicoverpa zea (Boddie). In this study, we evaluated the relative survival of H. zea in Bt events and in seed blends compared with pure stand refuge and the relative survival of H. zea on the individual components of the pyramid 1507xMON810xMIR162. The results showed variation on the production of H. zea in refuge plants from seed blends compared with pure stand refuge plants. The relative survival of H. zea on the events 1507, MON810, MIR162, and 1507xMON810xMIR162 ranked similarly across the three locations tested. These results can be used in computer simulation modeling efforts to evaluate the feasibility of seed blends as a refuge deployment strategy with the pyramid 1507xMON810xMIR162. Because the reduction on survival of H. zea due to blending was variable, a sensitivity analysis that includes all possible scenarios of reduction in survival should be considered. © 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.

  17. Carbon isotope ratios document that the elytra of western corn rootworm reflects adult versus larval feeding and later instar larvae prefer Bt corn to alternate hosts

    Science.gov (United States)

    The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a major pest of maize, Zea mays L., worldwide. While exploring conventional approaches to management and more recently bioengineering, extended research has been conducted on ways to manage its root-feeding larvae. The nee...

  18. Identification of a novel aminopeptidase P-like gene (OnAPP possibly involved in Bt toxicity and resistance in a major corn pest (Ostrinia nubilalis.

    Directory of Open Access Journals (Sweden)

    Chitvan Khajuria

    Full Text Available Studies to understand the Bacillus thuringiensis (Bt resistance mechanism in European corn borer (ECB, Ostrinia nubilalis suggest that resistance may be due to changes in the midgut-specific Bt toxin receptor. In this study, we identified 10 aminopeptidase-like genes, which have previously been identified as putative Bt toxin receptors in other insects and examined their expression in relation to Cry1Ab toxicity and resistance. Expression analysis for the 10 aminopeptidase-like genes revealed that most of these genes were expressed predominantly in the larval midgut, but there was no difference in the expression of these genes in Cry1Ab resistant and susceptible strains. This suggested that altered expression of these genes was unlikely to be responsible for resistance in these ECB strains. However, we found that there were changes in two amino acid residues of the aminopeptidase-P like gene (OnAPP involving Glu(305 to Lys(305 and Arg(307 to Leu(307 in the two Cry1Ab-resistant strains as compared with three Cry1Ab-susceptible strains. The mature OnAPP contains 682 amino acid residues and has a putative signal peptide at the N-terminus, a predicted glycosylphosphatidyl-inositol (GPI-anchor signal at the C-terminal, three predicted N-glycosylation sites at residues N178, N278 and N417, and an O-glycosylation site at residue T653. We used a feeding based-RNA interference assay to examine the role of the OnAPP gene in Cry1Ab toxicity and resistance. Bioassays of Cry1Ab in larvae fed diet containing OnAPP dsRNA resulted in a 38% reduction in the transcript level of OnAPP and a 25% reduction in the susceptibility to Cry1Ab as compared with larvae fed GFP dsRNA or water. These results strongly suggest that the OnAPP gene could be involved in binding the Cry1Ab toxin in the ECB larval midgut and that mutations in this gene may be associated with Bt resistance in these two ECB strains.

  19. Density-dependent and density-independent mortality of the western corn rootworm: impact on dose calculations of rootworm-resistant Bt corn.

    Science.gov (United States)

    Hibbard, Bruce E; Meihls, Lisa N; Ellersieck, Mark R; Onstad, David W

    2010-02-01

    The percentage of viable eggs of the western corn rootworm, Diabrotica virgifera virgifera LeConte, which survived to the adult stage was evaluated for the effect of egg density in 2005 and 2007 in central Missouri. In 2005, each plot was 2.44 by 3.05 m and contained 64 maize (corn), Zea mays L., plants. In 2007, plots were 3.05 by 3.05 m and again contained 64 corn plants. Seven egg densities (2,400, 1,200, 600, 300, 100, 50, and 25 viable eggs per 30.5 cm) were evaluated with four to six replications in each year in a completely randomized design. In 2007 only, an additional row was infested near each plot to evaluate plant damage. In both years, there was no correlation of infestation level and percentage of emergence between infestation levels of 25-600 viable eggs per 30.5 cm, indicating that density-dependent mortality did not occur at these egg densities. In 2005, 8.04% of the viable eggs established on a corn plant and produced an adult at these lower infestation rates. In 2007, this value was 2.9%. Regardless of egg density, approximately 92-97% failed to establish and produce adults (density-independent mortality). In 2005 and in the combined analysis, as viable egg densities increased from 600 to 2400 per 30.5 cm there was a significant decrease in percentage of emergence. In a broken line analysis of the 2005 data, the point where density-dependent mortality began in the combined analysis was 851 eggs per 30.5 cm with a 95% confidence interval from 678 to 1024. That year density-dependent mortality was important at high infestations and killed 54.4% of those larvae that successfully established on a plant at the highest egg density. However, little or no density-dependent mortality occurred at infestation levels corn rootworm.

  20. Bt pollen dispersal and Bt kernel mosaics: integrity of non-Bt refugia for lepidopteran resistance management in maize.

    Science.gov (United States)

    Burkness, Eric C; Hutchison, W D

    2012-10-01

    Field trials were conducted at Rosemount, MN in 2009 and 2010, to measure pollen movement from Bt corn to adjacent blocks of non-Bt refuge corn. As the use of Bt corn hybrids continues to increase in the United States, and new insect resistance management (IRM) plans are implemented, it is necessary to measure the efficacy of these IRM plans. In Minnesota, the primary lepidopteran pests of corn include the European corn borer, Ostrinia nubilalis (Hübner) and corn earworm, Helicoverpa zea (Boddie). The primary IRM plan in transgenic corn is the use of hybrids expressing a high dose of insecticidal proteins and an insect refuge containing hybrids not expressing insecticidal proteins that produce susceptible insects. Wind-assisted pollen movement in corn occurs readily, and is the primary method of pollination for corn. The combination of pollen movement and viability determines the potential for cross pollination of refuge corn. In 2009 and 2010, cross pollination occurred with the highest frequency on the north and east sides of Bt corn fields, but was found at some level in all directions. Highest levels of cross pollination (75%) were found within the first four rows (3 m) of non-Bt corn adjacent to Bt corn, and in general decreasing levels of cross pollination were found the further the non-Bt corn was planted from the Bt corn. A mosaic of Bt cross-pollinated kernels was found throughout the ear, but in both years the ear tip had the highest percentage of cross-pollinated kernels; this pattern may be linked to the synchrony of pollen shed and silking between Bt and non-Bt corn hybrids. The dominant wind direction in both years was from WNW. However, in both years, there were also prevailing winds from SSW and WSW. Further studies are needed to quantify Bt levels in cross-pollinated kernels, measure the Bt dose of such kernels and associated lepidopteran pest survival, and measure the impact of Bt pollen on lepidopteran pests, particularly when considering the

  1. In-field rates of decomposition and microbial communities colonizing residues vary by depth of residue placement and plant part, but not by crop genotype for residues from two Cry1AB Bt corn hybrids and their non-transgenic i

    Science.gov (United States)

    The adoption of Bt corn has been largely overshadowed by concerns about their unintended effects on human health and the environment. Residues of transgenic Bt crops decomposed more slowly than their non-transgenic isolines in one laboratory study, although no mechanism to explain these observations...

  2. Effect of Seed Blends and Soil-Insecticide on Western and Northern Corn Rootworm Emergence from mCry3A+eCry3.1Ab Bt Maize.

    Science.gov (United States)

    Frank, Daniel L; Kurtz, Ryan; Tinsley, Nicholas A; Gassmann, Aaron J; Meinke, Lance J; Moellenbeck, Daniel; Gray, Michael E; Bledsoe, Larry W; Krupke, Christian H; Estes, Ronald E; Weber, Patrick; Hibbard, Bruce E

    2015-06-01

    Seed blends containing various ratios of transgenic Bt maize (Zea mays L.) expressing the mCry3A+eCry3.1Ab proteins and non-Bt maize (near-isoline maize) were deployed alone and in combination with a soil applied pyrethroid insecticide (Force CS) to evaluate the emergence of the western corn rootworm, Diabrotica virgifera virgifera LeConte, in a total of nine field environments across the Midwestern United States in 2010 and 2011. Northern corn rootworm, Diabrotica barberi Smith & Lawrence emergence was also evaluated in four of these environments. Both western and northern corn rootworm beetle emergence from all Bt treatments was significantly reduced when compared with beetle emergence from near-isoline treatments. Averaged across all environments, western corn rootworm beetle emergence from 95:5, 90:10, and 80:20 seed blend ratios of mCry3A+eCry3.1Ab: near-isoline were 2.6-, 4.2-, and 6.7-fold greater than that from the 100:0 ratio treatment. Northern corn rootworm emergence from the same seed blend treatments resulted in 2.8-, 3.2-, and 4.2-fold more beetles than from the 100:0 treatment. The addition of Force CS (tefluthrin) significantly reduced western corn rootworm beetle emergence for each of the three treatments to which it was applied. Force CS also significantly delayed the number of days to 50% beetle emergence in western corn rootworms. Time to 50% beetle emergence in the 100% mCry3A+eCry3.1Ab treatment with Force CS was delayed 13.7 d when compared with western corn rootworm beetle emergence on near-isoline corn. These data are discussed in terms of rootworm resistance management. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  3. Host-plant diversity of the European corn borer Ostrinia nubilalis: what value for sustainable transgenic insecticidal Bt maize?

    Science.gov (United States)

    Bourguet, D; Bethenod, M T; Trouvé, C; Viard, F

    2000-01-01

    The strategies proposed for delaying the development of resistance to the Bacillus thuringiensis toxins produced by transgenic maize require high levels of gene flow between individuals feeding on transgenic and refuge plants. The European corn borer Ostrinia nubilalis (Hübner) may be found on several host plants, which may act as natural refuges. The genetic variability of samples collected on sagebrush (Artemisia sp.), hop (Humulus lupulus L.) and maize (Zea mays L.) was studied by comparing the allozyme frequencies for six polymorphic loci. We found a high level of gene flow within and between samples collected on the same host plant. The level of gene flow between the sagebrush and hop insect samples appeared to be sufficiently high for these populations to be considered a single genetic panmictic unit. Conversely, the samples collected on maize were genetically different from those collected on sagebrush and hop. Three of the six loci considered displayed greater between-host-plant than within-host-plant differentiation in comparisons of the group of samples collected on sagebrush or hop with the group of samples collected on maize. This indicates that either there is genetic isolation of the insects feeding on maize or that there is host-plant divergent selection at these three loci or at linked loci. These results have important implications for the potential sustainability of transgenic insecticidal maize. PMID:10902683

  4. Effects of Cry34/35Ab1 corn on the survival and development of western corn rootworm, Diabrotica virgifera virgifera.

    Science.gov (United States)

    Rudeen, Melissa L; Gassmann, Aaron J

    2013-06-01

    The western corn rootworm, Diabrotica virgifera virgifera LeConte, is a major agricultural pest that is managed with transgenic corn, Zea mays L., expressing genes from Bacillus thuringiensis Berliner (Bt). The effects of Bt corn producing Cry34/35Ab1 (event DAS-59122-7) and entomopathogens on the survival and development of larval D. v. virgifera were examined in laboratory, field and greenhouse experiments. Larvae preferred non-Bt over Bt corn in a laboratory experiment, and there was higher recovery from non-Bt corn than from Bt corn in a field experiment. In a greenhouse study, survival at 17 days did not differ significantly among non-Bt corn, Bt corn and a blend of Bt and non-Bt corn, but development was delayed on Bt corn. Older larvae fed non-Bt corn had lower survival when entomopathogenic nematodes were added, but no other effects of pathogen were detected. Bt corn producing Cry34/35Ab1 delayed larval development of D. v. virgifera and deterred feeding. In a mixture of Bt and non-Bt corn, larval development and survival were similar to non-Bt corn alone, suggesting that non-Bt plants in a blended refuge or a pure stand may produce a similar number of adult insects, and that timing of adult emergence may also be similar. © 2012 Society of Chemical Industry.

  5. Toward metrological traceability for DNA fragment ratios in GM quantification. 1. Effect of DNA extraction methods on the quantitative determination of Bt176 corn by real-time PCR.

    Science.gov (United States)

    Corbisier, Philippe; Broothaerts, Wim; Gioria, Sabrina; Schimmel, Heinz; Burns, Malcolm; Baoutina, Anna; Emslie, Kerry R; Furui, Satoshi; Kurosawa, Yasunori; Holden, Marcia J; Kim, Hyong-Ha; Lee, Yun-Mi; Kawaharasaki, Mamoru; Sin, Della; Wang, Jing

    2007-05-02

    An international CCQM-P60 pilot study involving eight national metrological institutes was organized to investigate if the quantification of genetically modified (GM) corn powder by real-time PCR was affected by the DNA extraction method applied. Four commonly used extraction methods were compared for the extraction of DNA from a GM Bt176 corn powder. The CTAB-based method yielded the highest DNA template quantity and quality. A difference in the 260 nm/230 nm absorbance ratio was observed among the different extraction methods. Real-time amplification of sequences specific for endogenous genes zein and hmg as well as transgenic sequences within the cryIA(b) gene and a fragment covering the junction between the transformed DNA and the plant genome were used to determine the GM percentage. The detection of the transgenic gene was affected by the quantity and quality of template used for the PCR reaction. The Bt176 percentages measured on diluted or purified templates were statistically different depending on the extraction method applied.

  6. Corn earworm (Lepidoptera: Noctuidae) in northeastern field corn: infestation levels and the value of transgenic hybrids.

    Science.gov (United States)

    Bohnenblust, Eric; Breining, Jim; Fleischer, Shelby; Roth, Gregory; Tooker, John

    2013-06-01

    Corn earworm, Helicoverpa zea (Boddie), is a polyphagous noctuid pest of agricultural crops across the United States that is gaining attention as a pest of field corn. Before the introduction of transgenic insect-resistant hybrids, this pest was largely ignored in field corn, but now many Bacillus thuringiensis (Bt) corn hybrids have activity against corn earworm. However, the value of control in the northeastern United States is unclear because the risk posed by corn earworm to field corn has not been well characterized. To understand the threat from corn earworm and the value of Bt hybrids in field corn, we assessed corn earworm injury in Bt and non-Bt hybrids at 16 sites across four maturity zones throughout Pennsylvania in 2010, and 10 sites in 2011. We also used corn earworm captures from the PestWatch pheromone trapping network to relate moth activity to larval damage in field corn. Corn earworm damage was less than one kernel per ear at 21 of 26 sites over both years, and the percentage of ears damaged was generally Bt hybrids suppressed corn earworm damage relative to non-Bt hybrids, but we found no differences among Bt traits. Cumulative moth captures through July effectively predicted damage at the end of the season. Currently, the additional benefit of corn earworm control provided by Bt hybrids is typically less than US$4.00/ha in northeastern field corn.

  7. Field evidence for the exposure of ground beetles to Cry1Ab from transgenic corn.

    Science.gov (United States)

    Zwahlen, Claudia; Andow, David A

    2005-01-01

    Non-target organisms associated with the soil might be adversely affected by exposure to the CrylAb protein from Bacillus thuringiensis (Bt) in transgenic corn (Zea mays L.). To check for such exposure, we used ELISA to test for Cry1Ab in ground beetles collected live from fields with Bt corn residues and Bt corn (Bt/Bt), Bt corn residues and non-Bt crops (Bt/non-Bt), or non-Bt corn residues and non-Bt crops (non-Bt/non-Bt). In fields with Bt corn residues (Bt/Bt and Bt/non-Bt), Cry1Ab was present in all seven species of ground beetles examined (Agonum placidum, Bembidion rupicola, Clivina impressefrons, Cyclotrachelus iowensis, Harpalus pensylvanicus, Poecilus chalcites, and Poecilus lucublandus). For the two most abundant species, P. chalcites and P. lucublandus, the proportion of beetles with Cry1Ab was significantly higher in Bt/Bt fields (0.50-1.0) and Bt/non-Bt fields (0.41-0.50) than in non-Bt/non-Bt fields (0.0). This is the first field evidence that some ground beetle species are exposed to Cry1Ab. The implications of exposure on the performance of these non-target organisms are unclear.

  8. Asian corn borer (ACB) and non-ACB pests in GM corn (Zea mays L.) in the Philippines.

    Science.gov (United States)

    Afidchao, Miladis M; Musters, C J M; de Snoo, Geert R

    2013-07-01

    The Asian corn borer (ACB), Ostrinia furnacalis (Guenée), has become the most damaging pest in corn in south-east Asia. Corn farmers in the Philippines have incurred great yield losses in the past decades because of ACB infestation. Bacillus thuringiensis (Bt) and Bt herbicide-tolerant (BtHT) corns have been developed to reduce borer attacks worldwide. This study assessed the extent of ACB and non-ACB pest infestations in both GM and non-GM corn in Isabela Province, the Philippines. Specific aims were to reinvestigate the efficacy of Bt corn in controlling ACB, to evaluate what parts of Bt corn plants are susceptible to ACB, to monitor the potential development of ACB resistance and to evaluate whether secondary pests dominate in an ACB-free Bt corn environment. The study involved preparatory interviews with farmers, site selection, field scouting and visual inspection of 200 plants along 200 m transect lines through 198 cornfields. Bt corn can efficiently reduce the ACB pest problem and reduce borer damage by 44%, to damage levels in Bt and BtHT corn of 6.8 and 7% respectively. The leaves of Bt corn were more susceptible, while cobs of Bt corn were less affected by ACB. Non-ACB pests were common in Bt toxin-free cornfields and reduced in non-GM cornfields where ACB was abundant. No secondary pest outbreaks were found in ACB-free Bt cornfields. Bt and BtHT corn hybrids containing the Cry1Ab protein performed well in Isabela Province. Reduced cob damage by ACB on Bt fields could mean smaller economic losses even with ACB infestation. The occurrence of ACB in Bt and BtHT cornfields, although at a moderate and insignificant level, could imply the potential development of resistance to Bt toxin. © 2012 Society of Chemical Industry.

  9. Helicoverpa zea and Bt cotton in the United States.

    Science.gov (United States)

    Luttrell, Randall G; Jackson, Ryan E

    2012-01-01

    Helicoverpa zea (Boddie), the bollworm or corn earworm, is the most important lepidopteran pest of Bt cotton in the United States. Corn is the preferred host, but the insect feeds on most flowering crops and wild host plants. As a cotton pest, bollworm has been closely linked to the insecticide-resistance prone Heliothis virescens (F.), tobacco budworm. Immature stages of the two species are difficult to separate in field environments. Tobacco budworm is very susceptible to most Bt toxins, and Bt cotton is considered to be "high dose." Bollworm is less susceptible to Bt toxins, and Bt cotton is not "high dose" for this pest. Bt cotton is routinely sprayed with traditional insecticides for bollworm control. Assays of bollworm field populations for susceptibility to Bt toxins expressed in Bt cotton have produced variable results since pre-deployment of Bt cottons in 1988 and 1992. Analyses of assay response trends have been used by others to suggest that field resistance has evolved to Bt toxins in bollworm, but disagreement exists on definitions of field resistance and confidence of variable assay results to project changes in susceptibility of field populations. Given historical variability in bollworm response to Bt toxins, erratic field control requiring supplemental insecticides since early field testing of Bt cottons, and dramatic increases in corn acreage in cotton growing areas of the Southern US, continued vigilance and concern for resistance evolution are warranted.

  10. Especies del género Euxesta Loew (Diptera: Ulidiidae (= Otitidae plagas de maíces dulces Bt en la provincia de Santa Fe, Argentina Species of the genus Euxesta Loew (Diptera: Ulidiidae (=Otitidae, pests of Bt sweet corn in Santa Fe province, Argentina

    Directory of Open Access Journals (Sweden)

    Isabel Bertolaccini

    2010-06-01

    Full Text Available Los maíces dulces Bt son atacados por especies del género Euxesta Loew, antes consideradas como plagas secundarias, lo que provoca daños severos en los maíces dulces del cinturón hortícola santafesino. Se han identificado dos especies del género, E. mazorca Steykal y E. eluta Loew, que aparecen en forma simultánea y causan severas pérdidas. En los ataques, las larvas comienzan a dañar los estigmas, luego se produce el vaciado de los granos, especialmente los apicales, aunque el daño pueden extenderse a toda la espiga. La acción de estas larvas constituye además una vía de ingreso de microorganismos saprofíticos, lo que se traduce en la pérdida del producto e impide su comercialización para consumo directo. El género Dettmeria Borgmeier (Hymenoptera: Figitidae fue identificado parasitando larvas del género Euxesta, aunque en bajo porcentaje.Bt sweet corn is attacked by species of the genus Euxesta Loew that were considered as secondary pests, causing severe damage to sweet corn in Santa Fe province (Argentina. Two species have been identified: E. mazorca Steycal and E. eluta Loew, both appearing simultaneously and producing serious losses. Larvae attack the silks and consume the kernel contents, especially in the tips, although they can extend to all the ear length. The activity of these larvae constitutes one way of entrance for saprophytic microorganisms, making the product unmarketable for direct consumption. Dettmeria Borgmeier (Hymenoptera: Figitidae was identified parasitizing larvae of the genus Euxesta, but at a low level.

  11. Histopathological Effects of Bt and TcdA Insecticidal Proteins on the Midgut Epithelium of Western Corn Rootworm Larvae (Diabrotica virgifera virgifera

    Directory of Open Access Journals (Sweden)

    Andrew J. Bowling

    2017-05-01

    Full Text Available Western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte is a major corn pest in the United States, causing annual losses of over $1 billion. One approach to protect against crop loss by this insect is the use of transgenic corn hybrids expressing one or more crystal (Cry proteins derived from Bacillus thuringiensis. Cry34Ab1 and Cry35Ab1 together comprise a binary insecticidal toxin with specific activity against WCR. These proteins have been developed as insect resistance traits in commercialized corn hybrids resistant to WCR feeding damage. Cry34/35Ab1 is a pore forming toxin, but the specific effects of Cry34/35Ab1 on WCR cells and tissues have not been well characterized microscopically, and the overall histopathology is poorly understood. Using high-resolution resin-based histopathology methods, the effects of Cry34/35Ab1 as well as Cry3Aa1, Cry6Aa1, and the Photorhabdus toxin complex protein TcdA have been directly visualized and documented. Clear symptoms of intoxication were observed for all insecticidal proteins tested, including swelling and sloughing of enterocytes, constriction of midgut circular muscles, stem cell activation, and obstruction of the midgut lumen. These data demonstrate the effects of these insecticidal proteins on WCR midgut cells, and the collective response of the midgut to intoxication. Taken together, these results advance our understanding of the insect cell biology and pathology of these insecticidal proteins, which should further the field of insect resistance traits and corn rootworm management.

  12. Comparative data concerning aflatoxin contents in Bt maize and non-Bt isogenic maize in relation to human and animal health – a review

    Directory of Open Access Journals (Sweden)

    Vladimír Ostrý

    2015-01-01

    Full Text Available Transgenic Bt maize is a potentially important tool against insect pest in the EU and other countries. Bt maize (e.g. MON 810, Bt 11 which carries the Bt gene is highly resistant to larval feeding of European corn borer, stalk borer, and Southwestern corn borer, depending on Bt toxin (δ toxin production. Effective measures used to fight pests may often have positive side-effects in that they may also contribute to reducing mycotoxin concentrations. A systematic review has been used for the purposes of evaluating the studies on the reduction of aflatoxins in Bt maize. According to five studies, Bt maize has significantly lower concentrations of aflatoxins than non-Bt maize hybrids, only one study has shown no significant effect of Bt maize. Other studies have shown mixed results (four studies. The results of these studies were influenced by the year of sampling or by using maize breeding lines selected for resistance to aflatoxin accumulation.

  13. The impact of common smut(Ustilago maydis) on aflatoxin and fumonisin in transgenic Bt and non-Bt maize (Zea mays)

    Science.gov (United States)

    Corn infected with Ustilago maydis (common smut), produces galls that are valued food in certain cultures, but may be contaminated with mycotoxins. Field studies conducted in Elizabeth, Mississippi used near-isogenic Bt and non-Bt corn hybrids. The levels of aflatoxin and fumonisin were determined ...

  14. Biological characteristics of black armyworm Spodoptera cosmioides on genetically modified soybean and corn crops that express insecticide Cry proteins

    Directory of Open Access Journals (Sweden)

    Gabriela Vieira Silva

    2016-09-01

    Full Text Available ABSTRACT This study aimed to evaluate the development and reproduction of the black armyworm, Spodoptera cosmioides when larvae fed on leaves of Bt-corn hybrids, expressing a single Cry1F and also Cry1F, Cry1A.105 and Cry2Ab2 in pyramided corn and their non-Bt-isoline (hybrid 2B688, as well as on leaves of two soybean isolines expressing the Cry1Ac protein and its non-Bt isoline (A5547-227. We also assessed the effect of these Bt and non-Bt plants on the leaf consumption rate of S. cosmioides larvae. This pest was unable to develop when fed on any of the corn isolines (Bt and non-Bt. When both 1st and 3rd instar larvae were fed on corn leaf, mortality was 100% in both Bt and non-Bt corn. In contrast, when corn leaves were offered to 5th instar larvae, there were survivors. Defoliation and leaf consumption was higher with non-Bt corn than with both of the Bt corn isolines. There was no negative effect of Bt soybean leaves on the development and reproduction of S. cosmioides with respect to all evaluated parameters. Our study indicates that both Bt and non-Bt corn adversely affect the development of S. cosmioides while Bt soybean did not affect its biology, suggesting that this lepidopteran has major potential to become an important pest in Bt soybean crops.

  15. Injury and interplant compensation for southwestern corn borer (Lepidoptera: Crambidae) infestations in field corn.

    Science.gov (United States)

    Steckel, S; Stewart, S D

    2013-04-01

    Growers that plant Bacillus thuringiensis (Bt) Berliner corn (Zea mays L.) hybrids are required to plant non-Bt corn for resistance management. Refuge in a bag (RIB) is an emerging approach for resistance management where, for some hybrids having multiple Bt traits for a target species, the refuge is planted as a blend of Bt and non-Bt corn. Studies were conducted to evaluate how southwestern corn borer (Diatraea grandiosella Dyar), when infested at different densities and growth stages, affected the yield of infested, non-Bt plants and neighboring Bt plants. Infesting non-Bt corn plants with southwestern corn borer larvae caused significant injury. Both the number of larvae infested on plants and the timing of these infestations affected the number of kernels per ear, total kernel weight, and the weight of individual kernels. Infestation timing was more important than the number of larvae inoculated onto plants, with pretassel infestations causing more yield loss. There was little compensation by Bt plants that were adjacent to infested plants. Thus, the risk of yield loss from stalk tunneling larvae in a refuge in a bag scenario should be directly proportional to the percentage of non-Bt plants and the level of yield loss observed in these non-Bt plants. Because current refuge in a bag systems have five or 10% non-Bt corn plants within the seed unit, the likelihood of substantial yield losses from infestations of corn boring larvae is remote given our results, especially for infestations that occur after silking has begun.

  16. 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.

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

    Science.gov (United States)

    Dively, Galen P.

    2017-01-01

    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. PMID:28680673

  18. Efficacy of pyramided Bt proteins Cry1F, Cry1A.105, and cry2Ab2 expressed in Smartstax corn hybrids against lepidopteran insect pests in the northern United States.

    NARCIS (Netherlands)

    Rule, D.M.; Nolting, S.P.; Prasfika, P.L.; Storer, N.P.; Hopkins, B.W.; Scherder, E.J.A.; Siebert, M.W.; Hendrix, W.H.

    2014-01-01

    Commercial field corn (Zea mays L.) hybrids transformed to express some or all of the lepidopteran insect-resistant traits present in SmartStax corn hybrids were evaluated for insecticidal efficacy against a wide range of lepidopteran corn pests common to the northern United States, during 2008 to

  19. Responses by earthworms to reduced tillage in herbicide tolerant maize and Bt maize cropping systems

    DEFF Research Database (Denmark)

    Krogh, P. H.; Griffiths, B.; Demsar, D.

    2007-01-01

    studies of Bt corn and a glufosinate ammonium tolerant corn and included a reduced tillage treatment (RT) and a conventional tillage treatment (CT) as examples of a likely concomitant change in the agricultural practise. At a French study site at Varois, (Bourgogne), a field grown with the Bt...

  20. Evidence of resistance to Cry34/35Ab1 corn by western corn rootworm: root injury in the field and larval survival in plant-based bioassays

    Science.gov (United States)

    Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a serious pest of corn in the United States and recent management of western corn rootworm has included planting of Bt corn. Beginning in 2009, western corn rootworm populations with resistance to Cry3Bb1 c...

  1. Report: EPA Needs Better Data, Plans and Tools to Manage Insect Resistance to Genetically Engineered Corn

    Science.gov (United States)

    Report #16-P-0194, June 1, 2016. Bt crops have reduced insecticide applications by 123 million pounds. The EPA can preserve this significant public benefit through enhanced monitoring and preparation to address insect resistance in Bt corn.

  2. IT-BT convergence technology

    International Nuclear Information System (INIS)

    2012-12-01

    This book explains IT-BT convergence technology as the future technology, which includes a prolog, easy IT-BT convergence technology that has infinite potentials for new value, policy of IT-BT convergence technology showing the potential of smart Korea, IT-BT convergence opening happy future, for the new future of IT powerful nation Korea with IT-BT convergence technology and an epilogue. This book reveals the conception, policy, performance and future of IT-BT convergence technology.

  3. Effects of refuges on the evolution of resistance to transgenic corn by the western corn rootworm, Diabrotica virgifera virgifera LeConte.

    Science.gov (United States)

    Deitloff, Jennifer; Dunbar, Mike W; Ingber, David A; Hibbard, Bruce E; Gassmann, Aaron J

    2016-01-01

    Diabrotica virgifera virgifera LeConte is a major pest of corn and causes over a billion dollars of economic loss annually through yield reductions and management costs. Corn producing toxins derived from Bacillus thuringiensis (Bt) has been developed to help manage D. v. virgifera. However, previous studies have demonstrated the ability of this species to evolve resistance to Bt toxins in both laboratory and field settings. We used an experimental evolution approach to test the refuge strategies for delaying resistance of D. v. virgifera to corn producing Bt toxin Cry34/35Ab1. In the absence of refuges, D. v. virgifera developed resistance to Bt corn after three generations of selection. In some cases, non-Bt refuges reduced the level of resistance compared with the strain selected in the absence of refuges, but refuge strains did show reduced susceptibility to Bt corn compared with the unselected strain. In this study, non-Bt refuges delayed resistance to Bt corn by D. v. virgifera in some cases but not others. Combining the refuge strategy with pyramids of multiple Bt toxins and applying other pest management strategies will likely be necessary to delay resistance of D. v. virgifera to Bt corn. © 2015 Society of Chemical Industry.

  4. A biannual study on the environmental impact of Bt maize

    Czech Academy of Sciences Publication Activity Database

    Sehnal, František; Habuštová, Oxana; Spitzer, L.; Hussein, Hany; Růžička, Vlastimil

    2004-01-01

    Roč. 27, č. 3 (2004), s. 147-160 [Ecological Impact of Genetically Modified Organisms. Praha, 26.11.2003-29.11.2003] R&D Projects: GA ČR GA522/02/1507 Institutional research plan: CEZ:AV0Z5007907 Keywords : Bt maize * GM crops * European corn borer Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection

  5. Bacillus thuringiensis (Bt)

    Science.gov (United States)

    2004-01-01

    Bacillus thuringiensis (Bt), a natural bacteria found all over the Earth, has a fairly novel way of getting rid of unwanted insects. Bt forms a protein substance (shown on the right) that is not harmful to humans, birds, fish or other vertebrates. When eaten by insect larvae the protein causes a fatal loss of appetite. For over 25 years agricultural chemical companies have relied heavily upon safe Bt pesticides. New space based research promises to give the insecticide a new dimension in effectiveness and applicability. Researchers from the Consortium for Materials Development in Space along with industrial affiliates such as Abott Labs and Pern State University flew Bt on a Space Shuttle mission in the fall of 1996. Researchers expect that the Shuttle's microgravity environment will reveal new information about the protein that will make it more effective against a wider variety of pests.

  6. Assessment of fitness costs in Cry3Bb1 resistant and susceptible western corn rootworm (Coleoptera:Chrysomelidae) laboratory colonies

    Science.gov (United States)

    Maize production in the United States is dominated by plants genetically modified with transgenes from Bacillus thuringiensis (Bt). Varieties of Bt maize expressing Cry3Bb endotoxins that specifically target corn rootworms (genus Diabrotica) have proven highly efficacious. Howeve...

  7. Monitoring of Bt11 and Bt176 genetically modified maize in food sold commercially in Brazil from 2005 to 2007.

    Science.gov (United States)

    Dinon, Andréia Z; Bosco, Kenia T; Arisi, Ana Carolina M

    2010-07-01

    The first genetically modified (GM) maize lines were approved for trading in Brazil after December 2007 and they were T25, MON810, Bt11, NK603 and GA21. The polymerase chain reaction (PCR) method was employed to monitor the presence of Bt11 and nested PCR was used to detect the presence of Bt176 in 81 maize-derived products (maize flour, corn meal, maize flour flakes and polenta) that were sold in Brazilian market from 2005 to 2007, before the release of GM maize in Brazil. The PCR detection limit for Bt11 was 10 g kg(-1) and for nested PCR of Bt176 it was 1 g kg(-1). All Brazilian samples analyzed showed no positive signal for these GM maize events. Bt11 and Bt176 GM maize lines were not detected by specific PCR in 81 maize-derived food samples sold in Brazil from 2005 to 2007, before the commercial release of GM maize in Brazil. These Brazilian food industries were in compliance with the rules stipulated by the current legislation with respect to consumer requirements about GMO labeling.

  8. Ostrinia nubilalis parasitism and the field abundance of non-target insects in transgenic Bacillus thuringiensis corn (Zea mays).

    Science.gov (United States)

    Bourguet, Denis; Chaufaux, Josette; Micoud, Annie; Delos, Marc; Naibo, Bernard; Bombarde, Fany; Marque, Gilles; Eychenne, Nathalie; Pagliari, Carine

    2002-10-01

    In this study, we evaluated in field trials the effects on non-target species, of transgenic corn producing the Cry1Ab toxin of Bacillus thuringiensis (Bt). In 1998, we collected Ostrinia nubilalis (Hübner) larvae from transgenic Bt corn (Novartis Hybrid 176) and non-Bt corn at four geographical sites. We found a significant variation in parasitism by the tachinids Lydella thompsoni (Herting) and Pseudoperichaeta nigrolineata (Walker) among sites, and more parasitism in non-Bt than in Bt fields. The Bt effect did not vary significantly among fields. In 1999, we performed a field experiment at two sites, comparing the temporal abundance of non-target arthropods in Bt corn (Monsanto Hybrid MON810) and non-Bt corn. The non-target insects studied included the aphids Metopolophium dirhodum (Walker), Rhopalosiphum padi (L.) and Sitobion avenae (F.), the bug Orius insidiosus (Say), the syrphid Syrphus corollae (Meigen), the ladybird Coccinella septempunctata (L.), the lacewing Chrysoperla carnea (Stephens), thrips and hymenopteran parasitoids. For all species but one, the number of individuals varied greatly over the season but did not differ between the types of corn. The only exception was thrips which, at one site, was significantly more abundant in Bt corn than in non-Bt corn. However this difference did not remain significant when we took the multiple tests into account. Implications for pest resistance management, population dynamics and risk assessment are discussed.

  9. 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.

  10. Increased Survival of Western Corn Rootworm on Transgenic Corn Within Three Generations of Onplant Greenhouse Selection

    Science.gov (United States)

    The agricultural industry has adopted a high dose/refuge strategy as a means of delaying the onset of insect resistance to transgenic crops. Recently, Bt corn products developed for control of western corn rootworm (WCR), Diabrotica virgifera virgifera, have been introduced with less than high-dose...

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

    Science.gov (United States)

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

    2015-12-01

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

  12. Aflatoxin and Fumonisin in corn (Zea mays) infected by common smut Ustilago maydis

    Science.gov (United States)

    Corn infected with Ustilago maydis (common smut) produces galls that are valued food in certain cultures, but may be contaminated with mycotoxins. Field studies conducted in Elizabeth, Mississippi used near isogenic Bt and non-Bt corn hybrids. The levels of aflatoxin and fumonisin were determined i...

  13. Fitness costs associated with Cry1F resistance in the European corn borer

    Science.gov (United States)

    Crops producing insecticidal toxins derived from the soil bacterium Bacillus thuringiensis (Bt) are widely planted in order to manage key insect pests. Bt crops can provide an effective tool for pest management; however, the evolution of Bt resistance can diminish this benefit. The European corn b...

  14. Greenhouse-selected resistance to Cry3Bb1-producing corn in three western corn rootworm populations.

    Directory of Open Access Journals (Sweden)

    Lisa N Meihls

    Full Text Available Transgenic corn producing the Bacillus thuringiensis (Bt toxin Cry3Bb1 has been useful for controlling western corn rootworm, Diabrotica virgifera virgifera LeConte, one of the most economically important crop pests in the United States. However, rapid evolution of resistance by this beetle to Bt corn producing Cry3Bb1 has been reported previously from the laboratory, greenhouse, and field. Here we selected in the greenhouse for resistance to Cry3Bb1 corn in three colonies of WCR derived from Kansas, Minnesota, and Wisconsin, respectively. Three generations of rearing on Cry3Bb1 corn significantly increased larval survival on Cry3Bb1 corn, resulting in similar survival in the greenhouse for selected colonies on Cry3Bb1 corn and isoline corn that does not produce Bt toxin. After four to seven generations of rearing on Cry3Bb1 corn, survival in the field on Cry3Bb1 corn relative to isoline corn more than doubled for selected colonies (72% compared with control colonies (33%. For both selected and control colonies, survival in the field was significantly lower on Cry3Bb1 corn than on isoline corn. On isoline corn, most fitness components were similar for selected colonies and control colonies. However, fecundity was significantly lower for selected colonies than control colonies, indicating a fitness cost associated with resistance. The rapid evolution of resistance by western corn rootworm to Bt corn reported here and previously underlines the importance of effective resistance management for this pest.

  15. Complementation of sweet corn mutants: a method for grouping ...

    Indian Academy of Sciences (India)

    Maize endosperm mutant genes that affect quality of sweet corn can be grouped in two classes. One group of mutants namely brittle1 (bt1), brittle2 (bt2) and shrunken2 (sh2) .... significant influence on yield improvement, efficient test- ing of hybrids, and increasing the probability of identify- ing desirable hybrids (Tracy 1990).

  16. Field-evolved resistance by western corn rootworm to multiple Bacillus thuringiensis toxins in transgenic maize.

    Science.gov (United States)

    Gassmann, Aaron J; Petzold-Maxwell, Jennifer L; Clifton, Eric H; Dunbar, Mike W; Hoffmann, Amanda M; Ingber, David A; Keweshan, Ryan S

    2014-04-08

    The widespread planting of crops genetically engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) places intense selective pressure on pest populations to evolve resistance. Western corn rootworm is a key pest of maize, and in continuous maize fields it is often managed through planting of Bt maize. During 2009 and 2010, fields were identified in Iowa in which western corn rootworm imposed severe injury to maize producing Bt toxin Cry3Bb1. Subsequent bioassays revealed Cry3Bb1 resistance in these populations. Here, we report that, during 2011, injury to Bt maize in the field expanded to include mCry3A maize in addition to Cry3Bb1 maize and that laboratory analysis of western corn rootworm from these fields found resistance to Cry3Bb1 and mCry3A and cross-resistance between these toxins. Resistance to Bt maize has persisted in Iowa, with both the number of Bt fields identified with severe root injury and the ability western corn rootworm populations to survive on Cry3Bb1 maize increasing between 2009 and 2011. Additionally, Bt maize targeting western corn rootworm does not produce a high dose of Bt toxin, and the magnitude of resistance associated with feeding injury was less than that seen in a high-dose Bt crop. These first cases of resistance by western corn rootworm highlight the vulnerability of Bt maize to further evolution of resistance from this pest and, more broadly, point to the potential of insects to develop resistance rapidly when Bt crops do not achieve a high dose of Bt toxin.

  17. 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

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

    Science.gov (United States)

    Dively, Galen P; Venugopal, P Dilip; Finkenbinder, Chad

    2016-01-01

    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. 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. After ruling out possible contributing factors, the rapid change in field efficacy in recent years and decreased susceptibility of H. zea to Bt sweet corn provide strong evidence of field-evolved resistance in H

  19. Effects of feeding silage and grain from glyphosate-tolerant or insect-protected corn hybrids on feed intake, ruminal digestion, and milk production in dairy cattle.

    Science.gov (United States)

    Donkin, S S; Velez, J C; Totten, A K; Stanisiewski, E P; Hartnell, G F

    2003-05-01

    Lactating dairy cows were used to determine effects of feeding glyphosate-tolerant or insect-protected corn hybrids on feed intake, milk production, milk composition, and ruminal digestibility. Corn resistant to European corn borer (Ostrinia nubilalis) infestation (Bt-MON810), or its nontransgenic control (Bt-CON), were planted in alternating fields during two successive years. One-half of each strip was harvested for whole plant corn silage and the remainder was allowed to mature and harvested as grain. Effects of feeding diets containing either Bt-MON810 or Bt-CON grain and silage were determined in two experiments (1 and 2) conducted during successive years. In experiment 3, glyphosate-tolerant Roundup Ready corn (RR-GA21) or its nontransgenic control (RR-CON) corn were grown in alternating fields during one cropping season. Diets contained 42 to 60% corn silage and 20 to 34% corn grain from Bt-MON810, RR-GA21, or the appropriate nontransgenic counterpart; treatments were applied using a switchback design. Cows were fed ad libitum and milked twice daily. There were no differences for nutrient composition between silage sources or between grain sources within an experiment. Data for experiments 1 and 2 indicated similar dry matter intake (DMI), 4% fat-corrected milk (FCM) production, and milk composition between Bt-MON810 and Bt-CON diets. There were no differences for DMI, 4% FCM production, and milk composition between RR-GA21 and RR-CON diets. There was no difference in ruminal degradability, determined separately for corn silage and corn grain, for RR-GA21 or Bt-MON810-hybrids compared with their respective controls. These data demonstrate equivalence of nutritional value and production efficiency for corn containing Bt-MON810 compared with its control and for RR-GA21 corn compared with its control.

  20. Notification: Evaluation of Office of Pesticide Programs’ Genetically Engineered Corn Insect Resistance Management

    Science.gov (United States)

    Project #OPE-FY15-0055, July 09, 2015. The EPA OIG plans to begin preliminary research on the EPA's ability to manage and prevent increased insect resistance to genetically engineered Bacillus thuringiensis (Bt) corn.

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

    Science.gov (United States)

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

    2013-02-01

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

  2. The effect of nitrogen rate on transgenic corn Cry3Bb1 protein expression.

    Science.gov (United States)

    Marquardt, Paul T; Krupke, Christian H; Camberato, James J; Johnson, William G

    2014-05-01

    Combining herbicide-resistant and Bacillus thuringiensis (Bt) traits in corn (Zea mays L.) hybrids may affect insect resistance management owing to volunteer corn. Some Bt toxins may be expressed at lower levels by nitrogen-deficient corn roots. Corn plants with sublethal levels of Bt expression could accelerate the evolution of Bt resistance in target insects. The present objective was to quantify the concentration of Bt (Cry3Bb1) in corn root tissue with varying tissue nitrogen concentrations. Expression of Cry3Bb1 toxin in root tissue was highly variable, but there were no differences in the overall concentration of Cry3Bb1 expressed between roots taken from Cry3Bb1-positive volunteer and hybrid corn plants. The nitrogen rate did affect Cry3Bb1 expression in the greenhouse, less nitrogen resulted in decreased Cry3Bb1 expression, yet this result was not documented in the field. A positive linear relationship of plant nitrogen status on Cry3Bb1 toxin expression was documented. Also, high variability in Cry3Bb1 expression is potentially problematic from an insect resistance management perspective. This variability could create a mosaic of toxin doses in the field, which does not fit into the high-dose refuge strategy and could alter predictions about the speed of evolution of resistance to Cry3Bb1 in western corn rootworm Diabrotica virgifera virgifera LeConte. © 2013 Society of Chemical Industry.

  3. High susceptibility of Bt maize to aphids enhances the performance of parasitoids of lepidopteran pests.

    Directory of Open Access Journals (Sweden)

    Cristina A Faria

    Full Text Available Concerns about possible undesired environmental effects of transgenic crops have prompted numerous evaluations of such crops. So-called Bt crops receive particular attention because they carry bacteria-derived genes coding for insecticidal proteins that might negatively affect non-target arthropods. Here we show a remarkable positive effect of Bt maize on the performance of the corn leaf aphid Rhopalosiphum maidis, which in turn enhanced the performance of parasitic wasps that feed on aphid honeydew. Within five out of six pairs that were evaluated, transgenic maize lines were significantly more susceptible to aphids than their near-isogenic equivalents, with the remaining pair being equally susceptible. The aphids feed from the phloem sieve element content and analyses of this sap in selected maize lines revealed marginally, but significantly higher amino acid levels in Bt maize, which might partially explain the observed increased aphid performance. Larger colony densities of aphids on Bt plants resulted in an increased production of honeydew that can be used as food by beneficial insects. Indeed, Cotesia marginiventris, a parasitoid of lepidopteran pests, lived longer and parasitized more pest caterpillars in the presence of aphid-infested Bt maize than in the presence of aphid-infested isogenic maize. Hence, depending on aphid pest thresholds, the observed increased susceptibility of Bt maize to aphids may be either a welcome or an undesirable side effect.

  4. Evaluation of corn hybrids expressing Cry1F, cry1A.105, Cry2Ab2, Cry34Ab1/Cry35Ab1, and Cry3Bb1 against southern United States insect pests.

    Science.gov (United States)

    Siebert, M W; Nolting, S P; Hendrix, W; Dhavala, S; Craig, C; Leonard, B R; Stewart, S D; All, J; Musser, F R; Buntin, G D; Samuel, L

    2012-10-01

    Studies were conducted across the southern United States to characterize the efficacy of multiple Bacillus thuringiensis (Bt) events in a field corn, Zea mays L., hybrid for control of common lepidopteran and coleopteran pests. Cry1F protein in event TC1507 and Cry1A.105 + Cry2Ab2 proteins in event MON 89034 were evaluated against pests infesting corn on above-ground plant tissue including foliage, stalks, and ears. Cry34Ab1/Cry35Ab1 proteins in event DAS-59122-7 and Cry3Bb1 in event MON 88017 were evaluated against the larvae of Mexican corn rootworm, Diabrotica virgifera zeae Krysan and Smith, which occur below-ground. Field corn hybrids containing Cry1F, Cry1A.105 + Cry2Ab2, Cry34Ab1/Cry35Ab1, and Cry3Bb1 insecticidal proteins (SmartStax) consistently demonstrated reductions in plant injury and/or reduced larval survivorship as compared with a non-Bt field corn hybrid. Efficacy provided by a field corn hybrid with multiple Bt proteins was statistically equal to or significantly better than corn hybrids containing a single event active against target pests. Single event field corn hybrids provided very high levels of control of southwestern corn borer, Diatraea grandiosella (Dyar), lesser cornstalk borer, Elasmopalpus lignosellus (Zeller), and fall armyworm, Spodoptera frugiperda (J.E. Smith), and were not significantly different than field corn hybrids with multiple events. Significant increases in efficacy were observed for a field corn hybrid with multiple Bt events for sugarcane borer, Diatraea saccharalis (F.), beet armyworm, Spodoptera exigua (Hübner), corn earworm, Helicoverpa zea (Boddie), and Mexican corn rootworm. Utilization of field corn hybrids containing multiple Bt events provides a means for managing insect resistance to Bt proteins and reduces non-Bt corn refuge requirements.

  5. Corn stalk as matrix in decomposting toilet for treating urine and feces

    Science.gov (United States)

    Sintawardani, N.; Nilawati, D.; Astuti, J. T.

    2017-03-01

    Bio-Toilet technology (BT) which is appropriate for the habits of Indonesian people has been studied and developed. BT is a dry toilet technology commonly uses ligno-cellulosic waste materials as matrix to facilitate the growth of natural microbes. In aerobic condition, microbes degrade feces and urine. Mineral as the leftover of feces and urine, such as nitrogen (N), phosphorus (P), and potassium (K) remain in the rest of matrix waste. After certain period. matrix can be harvested and used as soil conditioner. BT uses much less water, mobile, and very useful to be applied in areas where water availability is limited. BT type with different capacities, user amounts and mixing systems has been developed using sawdust for matrix. Since corn stalk is categorized as useless and priceless waste, its application in BT is challenging. Performance of BT with corn stalk as matrix to degrade feces and urine of carnivore imitating the human waste was observed. BT M-15 manual mixing type with paddle was filled with chopped corn stalk as much as 45% of total volume. This BT was designed for 15 person as users per day if 80% reactor volume was filled with ligno-cellulosic matrix. It is assumed that 150 g of feces are discharged once per person/day and 1000 mL of urine 6-8 times per day. Start up process was made in the beginning to initialize the needed microbes in the reactor (matrix). The discharge of feces and urine were increased slowly and gradually the users were increased from 1 to 4 users per day. Performance of BT was indicated by the change in the pile that showed by moisture content, temperature and pH. C/N ratio in matrix decreased significantly from 43 to 17. This result showed that the corn stalk could be used as matrix in BT.

  6. The Impact of Volunteer Corn on Crop Yields and Insect Resistance Management Strategies

    Directory of Open Access Journals (Sweden)

    Paul T. Marquardt

    2013-06-01

    Full Text Available Volunteer corn (VC has reemerged as a problematic weed in corn/soybean rotational cropping systems. This reemergence and increasing prevalence of volunteer corn has been correlated to an increased adoption of herbicide-resistant (HR corn hybrids and the adoption of conservation tillage. Since the introduction of HR crops, control options, weed/crop competition, and other concerns (i.e., insect resistance management of Bt traits have increased the amount of attention that volunteer corn is receiving. The objective of this review is to discuss what is known about VC prior to and after the introduction of HR crops, and to discuss new information about this important weed.

  7. Investigating Transgenic Corn Hybrids as a Method for Mycotoxin Control

    Science.gov (United States)

    Transgenic Bt corn hybrids have been available for more than 10 years and are known to control specific insects. More recently, so-called “stacked-gene” hybrids, have been released with multiple insect resistance genes and genes for herbicide resistance, resulting in up to 6 traits per plant. Beca...

  8. The causes and unintended consequences of a paradigm shift in corn production practices

    International Nuclear Information System (INIS)

    Fausti, Scott W.

    2015-01-01

    Highlights: • Biotechnology adoption and the U.S. corn production system are causally linked. • U.S. agriculture and energy policy choices merged to incentivize U.S. corn production. • U.S. biofuel energy policy contributed to the adoption of Bt corn seed technology. • Policy alternatives to modify the corn-based ethanol production system are provided. - Abstract: Independent but simultaneously occurring changes in U.S. agricultural and energy policies in conjunction with advances in biotechnology converged to create an economic and regulatory environment that incentivized corn acreage expansion. Advancements in Bt seed and ethanol production technologies contributed to scale efficiency gains in corn and biofuel production. These advancements were accompanied by changes in market forces that altered the balance between corn and other agricultural crop production. The causal linkages among Bt adoption, ethanol production, and corn production are explored along with a discussion of how this shift toward corn production generated unexpected economic and environmental consequences. Alternative policy solutions to mitigate the negative consequences and enhance the resiliency of U.S. agriculture are discussed

  9. Effects of 90-Day Feeding of Transgenic Maize BT799 on the Reproductive System in Male Wistar Rats

    Directory of Open Access Journals (Sweden)

    Qian-ying Guo

    2015-12-01

    Full Text Available BT799 is a genetically modified (GM maize plant that expresses the Cry1Ac gene from Bacillus thuringiensis (Bt. The Cry1Ac gene was introduced into maize line Zhen58 to encode the Bt crystal protein and thus produce insect-resistant maize BT799. Expression of Bt protein in planta confers resistance to Lepidopteran pests and corn rootworms. The present study was designed to investigate any potential effects of BT799 on the reproductive system of male rats and evaluate the nutritional value of diets containing BT799 maize grain in a 90-day subchronic rodent feeding study. Male Wistar rats were fed with diets containing BT799 maize flours or made from its near isogenic control (Zhen58 at a concentration of 84.7%, nutritionally equal to the standard AIN-93G diet. Another blank control group of male rats were treated with commercial AIN-93G diet. No significant differences in body weight, hematology and serum chemistry results were observed between rats fed with the diets containing transgenic BT799, Zhen58 and the control in this 13-week feeding study. Results of serum hormone levels, sperm parameters and relative organ/body weights indicated no treatment-related side effects on the reproductive system of male rats. In addition, no diet-related changes were found in necropsy and histopathology examinations. Based on results of the current study, we did not find any differences in the parameters tested in our study of the reproductive system of male rats between BT799 and Zhen58 or the control.

  10. Fitness of Bt-resistant cabbage loopers on Bt cotton plants.

    Science.gov (United States)

    Tetreau, Guillaume; Wang, Ran; Wang, Ping

    2017-10-01

    Development of resistance to the insecticidal toxins from Bacillus thuringiensis (Bt) in insects is the major threat to the continued success of transgenic Bt crops in agriculture. The fitness of Bt-resistant insects on Bt and non-Bt plants is a key parameter that determines the development of Bt resistance in insect populations. In this study, a comprehensive analysis of the fitness of Bt-resistant Trichoplusia ni strains on Bt cotton leaves was conducted. The Bt-resistant T. ni strains carried two genetically independent mechanisms of resistance to Bt toxins Cry1Ac and Cry2Ab. The effects of the two resistance mechanisms, individually and in combination, on the fitness of the T. ni strains on conventional non-Bt cotton and on transgenic Bt cotton leaves expressing a single-toxin Cry1Ac (Bollgard I) or two Bt toxins Cry1Ac and Cry2Ab (Bollgard II) were examined. The presence of Bt toxins in plants reduced the fitness of resistant insects, indicated by decreased net reproductive rate (R 0 ) and intrinsic rate of increase (r). The reduction in fitness in resistant T. ni on Bollgard II leaves was greater than that on Bollgard I leaves. A 12.4-day asynchrony of adult emergence between the susceptible T. ni grown on non-Bt cotton leaves and the dual-toxin-resistant T. ni on Bollgard II leaves was observed. Therefore, multitoxin Bt plants not only reduce the probability for T. ni to develop resistance but also strongly reduce the fitness of resistant insects feeding on the plants. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  11. Selection for Cry3Bb1 resistance in a genetically diverse population of nondiapausing Western Corn Rootworm (Coleoptera: Chrysomelidae)

    Science.gov (United States)

    Five short-diapause laboratory lines of western corn rootworm (Diabrotica virgifera virgifera) were selected for resistance to MON863, a variety of corn genetically modified with the Bacillus thuringiensis (Bt) transgene that expresses the Cry3Bb1 endotoxin. Three of the selecte...

  12. Variation in microRNA levels between Cry1Ab-resistant and susceptible strains of the European corn borer, Ostrinia nubilalis (Hübner)

    Science.gov (United States)

    Transgenic maize hybrids that express insecticidal Bacillus thuringiensis (Bt) crystalline (Cry) protein toxins effectively protect against feeding damage inflicted by the insect pest the European corn borer, Ostrinia nubilalis. Field monitoring and laboratory selections have detected varying level...

  13. EVALUATION OF BIOASSAYS FOR TESTING Bt SWEETPOTATO ...

    African Journals Online (AJOL)

    ACSS

    2013-07-24

    Jul 24, 2013 ... therefore, inedible by humans due to terpenoid produced in response to ... Bacillus thuringiensis (Bt) through genetic engineering. Genes expressing insecticidal crystal. (Cry) proteins from Bt have been cloned, modified for expression in ..... fold less dry matter, stressed larva, and pro-toxins which are more ...

  14. THE EUROPEAN CORN BORER (OSTRINIA NUBILALIS HÜBNER REVIEW OF RESULTS FROM CROATIA

    Directory of Open Access Journals (Sweden)

    Marija Ivezić

    2001-06-01

    Full Text Available European Corn Borer (ECB - (Ostrinia nubilalis Hübner is one of the most important pest on corn in Croatia. In the last decade corn production was on over 400 000 ha, in Eastern Croatia. Although ECB is present every year, with no such a low intensity, their control is not implemented. Corn is grown in monoculture, at 40% of cornfields, which also has influence on spreading of ECB. In the last ten years average attack of ECB was 51.5%; been done three different kinds of trials for controlling ECB. First trials were carried out in DeKalb hybrids, and ECB was controlled by Biobit XL, on the base of Bacillus thuringiensis Berliner. Intensity of attack was decreased for 46%. Second trial was carried out in ten hybrids, in order to determine the tolerance of hybrids against ECB. It was identified that several domestic hybrids (OSSK 382, OSSK 664 and BC 462 are tolerant to ECB. The third trial was carried out with GM hybrids. Experiments included Pioneer hybrids Evelina Bt, and Landia Bt. Intensity of attack at Evelina standard was 52%, while in Evelina Bt, ECB wasn't present at all. At Landia standard ECB was present on 98%, while in Landia Bt, intensity of attack was 21%. At both Bt hybrids, number of larvae and tunnels was lower comparing to standard hybrids. Length of damage in Landia check was 20.66 cm, while in Landia Bt it was 0.45 cm. The yield was increased for 10.27% at Evelina Bt, and for 26.67% in Landia Bt comparing to their standards. This kind of experiments will be continued in the future, not only because of its agronomic importance, but also because of its ecological relevance.

  15. Inheritance and Fitness Costs of Resistance to Cry3Bb1 Corn by Western Corn Rootworm (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Ingber, David A; Gassmann, Aaron J

    2015-10-01

    Transgenic crops that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are widely planted to manage pest insects. One of the primary pests targeted by Bt corn in the United States is western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). Cry3Bb1 corn for management of western corn rootworm was commercialized in 2003, and beginning in 2009, populations of western corn rootworm with field-evolved resistance to Cry3Bb1 corn were found in Iowa. Here we quantify the magnitude, inheritance, and fitness costs of resistance to Cry3Bb1 corn in two strains (Hopkinton and Cresco) derived from field populations that evolved resistance to Cry3Bb1 corn. For Hopkinton, we found evidence for complete resistance to Cry3Bb1 corn and nonrecessive inheritance. Additionally, no fitness costs of Cry3Bb1 resistance were detected for Hopkinton. For Cresco, resistance was incomplete and recessive, and we detected fitness costs affecting developmental rate, survival to adulthood, and fecundity. These results suggest that variation may exist among field populations in both the inheritance and accompanying fitness costs of resistance. To the extent that field populations exhibit nonrecessive inheritance and a lack of fitness cost, this will favor more rapid evolution of resistance than would be expected when resistance is functionally recessive and is accompanied by fitness costs. © 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. Does Bt maize cultivation affect the non-target insect community in the agro ecosystem?

    Directory of Open Access Journals (Sweden)

    Daniela Chaves Resende

    2016-03-01

    Full Text Available ABSTRACT The cultivation of genetically modified crops in Brazil has led to the need to assess the impacts of this technology on non-target species. Under field conditions, the potential effect on insect biodiversity was evaluated by comparing a homogeneous corn field with conventional and transgenic maize, expressing different Bt proteins in seven counties of Minas Gerais, Brazil. The richness pattern of non-target insect species, secondary pests and natural enemies were observed. The results do not support the hypothesis that Bt protein affects insect biodiversity. The richness and diversity data of insects studied were dependent on the location and other factors, such as the use of insecticides, which may be a major factor where they are used.

  17. Nitrogen Rate Effects on Cry3Bb1 and Cry3Bb1 + Cry34/35Ab1 Expression in Transgenic Corn Roots, Resulting Root Injury, and Corn Rootworm Beetle Emergence.

    Science.gov (United States)

    Leaf, T M; Ostlie, K R

    2017-06-01

    Nitrogen (N) application rates have been recommended historically for maximum economic yield of corn (Zea mays L.), but not for optimal expression or impacts of Bt (Bacillus thuringiensis Berliner) Cry protein(s) on target insects. This study explored the need to adjust N rates to optimize expression of corn rootworm-active Bt (Bt-RW) protein(s) in a single and a pyramided trait hybrid and resulting impacts on beetle emergence and root injury, under field conditions. The experiment featured a factorial treatment arrangement in a split-plot randomized complete block design with six N rates as the main plots and three hybrids (MON88017 expressing Cry3Bb1, MON88017 x DAS-59122 expressing Cry3Bb1 + Cry34/35Ab1, and a non-Bt-RW hybrid) as the subplots. Corn roots were sampled at the beginning of, and after, peak larval feeding to determine Bt-expression levels using an enzyme-linked immunosorbent assay. Beetles were collected every 2-3 d during emergence using cut-plant emergence cages. Cry3Bb1 expression was significantly reduced when little or no N was applied. Cry34Ab1 and Cry35Ab1 expression was highly variable and unaffected by N rate. Beetle emergence increased with N rate in the non-Bt-RW hybrid while root injury declined. Provided Bt-RW hybrids had sufficient applied N, root injury was relatively low. Results indicate that N management could affect Bt-RW expression and success of insect resistance management plans provided N is applied at rates that enhance production of susceptible beetles emerging from the non-Bt-RW (refuge) hybrid, and achieve optimal expression and efficacy of Bt traits. © 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.

  18. Susceptibility of northern corn rootworm Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae) to mCry3A and eCry3.1Ab Bacillus thuringiensis proteins

    Science.gov (United States)

    Susceptibility of the northern corn rootworm (NCR), to mCry3A and eCry3.1Ab proteins derived from Bacillus thuringiensis (Bt) was determined using a diet bioassay. Northern corn rootworm neonates were exposed to different concentrations of mCry3A and eCry3.1Ab, incorporated into artificial diet. Lar...

  19. The Effect of Farmers' Decisions on Pest Control with Bt Crops: A Billion Dollar Game of Strategy.

    Directory of Open Access Journals (Sweden)

    Alice E Milne

    2015-12-01

    Full Text Available A farmer's decision on whether to control a pest is usually based on the perceived threat of the pest locally and the guidance of commercial advisors. Therefore, farmers in a region are often influenced by similar circumstances, and this can create a coordinated response for pest control that is effective at a landscape scale. This coordinated response is not intentional, but is an emergent property of the system. We propose a framework for understanding the intrinsic feedback mechanisms between the actions of humans and the dynamics of pest populations and demonstrate this framework using the European corn borer, a serious pest in maize crops. We link a model of the European corn borer and a parasite in a landscape with a model that simulates the decisions of individual farmers on what type of maize to grow. Farmers chose whether to grow Bt-maize, which is toxic to the corn borer, or conventional maize for which the seed is cheaper. The problem is akin to the snow-drift problem in game theory; that is to say, if enough farmers choose to grow Bt maize then because the pest is suppressed an individual may benefit from growing conventional maize. We show that the communication network between farmers' and their perceptions of profit and loss affects landscape scale patterns in pest dynamics. We found that although adoption of Bt maize often brings increased financial returns, these rewards oscillate in response to the prevalence of pests.

  20. Quantification of Bt δ-endotoxins in leaf tissues of tropical Bt maize ...

    African Journals Online (AJOL)

    In Kenya, stem borers destroy an estimated 13.5% of farmers' annual maize harvest. Maize transformed using Bacillus thuringiensis (Bt) derived genes controls stem borers without negative effects to humans, livestock or the environment. The effectiveness and sustainability of Bt transgenic technology in the control of stem ...

  1. Quantification of Bt δ-endotoxins in leaf tissues of tropical Bt maize ...

    African Journals Online (AJOL)

    Murenga Mwimali

    2012-06-26

    Jun 26, 2012 ... In Kenya, stem borers destroy an estimated 13.5% of farmers' annual maize harvest. Maize transformed using Bacillus thuringiensis (Bt) derived genes controls stem borers without negative effects to humans, livestock or the environment. The effectiveness and sustainability of Bt transgenic technology.

  2. Western corn rootworm larval movement in a SmartStax seed blend scenarios

    Science.gov (United States)

    Insect resistance management (IRM) can extend the lifetime of management options, but depends on extensive knowledge of the biology of the pest species involved for an optimal plan. Recently, the Environmental Protection Agency (EPA) registered a seed blend refuge for two of the transgenic Bt corn ...

  3. Stochastic Corn Yield Response Functions to Nitrogen for Corn after Corn, Corn after Cotton, and Corn after Soybeans

    OpenAIRE

    Boyer, Christopher N.; Larson, James A.; Roberts, Roland K.; McClure, Angela T.; Tyler, Donald D.; Zhou, Vivian

    2013-01-01

    Deterministic and stochastic yield response plateau functions were estimated to determine the expected profit-maximizing nitrogen rates, yields, and net returns for corn grown after corn, cotton, and soybeans. The stochastic response functions were more appropriate than their deterministic counterparts, and the linear response stochastic plateau described the data the best. The profit-maximizing nitrogen rates were similar for corn after corn, cotton, and soybeans, but relative to corn after ...

  4. [Research of the Bt crop biomass dynamics upon the invasion of Bt-resistant pests. A mathematical model].

    Science.gov (United States)

    Rusakov, A V; Medvinskiĭ, A B; Li, B -L; Gonik, M M

    2009-01-01

    The results of simulations of some consequences of the invasion of Bt-resistant pests into an agricultural ecosystem containing a Bt crop are presented. It is shown that the invasion of Bt-resistant pests leads to changes in the plant biomass dynamics, a decrease in the Bt crop production, and the deterioration of the predictability of the Bt crop production. We show that the parameter values at which the badly predictable Bt crop production takes place, occupy a minor area in the model parameter space. The size of the area depends on the insect reproduction period and the duration of the growing season.

  5. Similar genetic basis of resistance to Bt toxin Cry1Ac in Boll-selected and diet-selected strains of pink bollworm.

    Directory of Open Access Journals (Sweden)

    Jeffrey A Fabrick

    Full Text Available Genetically engineered cotton and corn plants producing insecticidal Bacillus thuringiensis (Bt toxins kill some key insect pests. Yet, evolution of resistance by pests threatens long-term insect control by these transgenic Bt crops. We compared the genetic basis of resistance to Bt toxin Cry1Ac in two independently derived, laboratory-selected strains of a major cotton pest, the pink bollworm (Pectinophora gossypiella [Saunders]. The Arizona pooled resistant strain (AZP-R was started with pink bollworm from 10 field populations and selected with Cry1Ac in diet. The Bt4R resistant strain was started with a long-term susceptible laboratory strain and selected first with Bt cotton bolls and later with Cry1Ac in diet. Previous work showed that AZP-R had three recessive mutations (r1, r2, and r3 in the pink bollworm cadherin gene (PgCad1 linked with resistance to Cry1Ac and Bt cotton producing Cry1Ac. Here we report that inheritance of resistance to a diagnostic concentration of Cry1Ac was recessive in Bt4R. In interstrain complementation tests for allelism, F(1 progeny from crosses between AZP-R and Bt4R were resistant to Cry1Ac, indicating a shared resistance locus in the two strains. Molecular analysis of the Bt4R cadherin gene identified a novel 15-bp deletion (r4 predicted to cause the loss of five amino acids upstream of the Cry1Ac-binding region of the cadherin protein. Four recessive mutations in PgCad1 are now implicated in resistance in five different strains, showing that mutations in cadherin are the primary mechanism of resistance to Cry1Ac in laboratory-selected strains of pink bollworm from Arizona.

  6. Soil microbial biomass and root growth in Bt and non-Bt cotton

    Science.gov (United States)

    Tan, D. K. Y.; Broughton, K.; Knox, O. G.; Hulugalle, N. R.

    2012-04-01

    The introduction of transgenic Bacillus thuringiensis (Bt) cotton (Gossypium hirsutum L.) has had a substantial impact on pest management in the cotton industry. While there has been substantial research done on the impact of Bt on the above-ground parts of the cotton plant, less is known about the effect of Bt genes on below ground growth of cotton and soil microbial biomass. The aim of this research was to test the hypothesis that Bt [Sicot 80 BRF (Bollgard II Roundup Ready Flex®)] and non-Bt [Sicot 80 RRF (Roundup Ready Flex®)] transgenic cotton varieties differ in root growth and root turnover, carbon indices and microbial biomass. A field experiment was conducted in Narrabri, north-western NSW. The experimental layout was a randomised block design and used minirhizotron and core break and root washing methods to measure cotton root growth and turnover during the 2008/09 season. Root growth in the surface 0-0.1 m of the soil was measured using the core break and root washing methods, and that in the 0.1 to 1 m depth was measured with a minirhizotron and an I-CAP image capture system. These measurements were used to calculate root length per unit area, root carbon added to the soil through intra-seasonal root death, carbon in roots remaining at the end of the season and root carbon potentially added to the soil. Microbial biomass was also measured using the ninhydrin reactive N method. Root length densities and length per unit area of non-Bt cotton were greater than Bt cotton. There were no differences in root turnover between Bt and non-Bt cotton at 0-1 m soil depth, indicating that soil organic carbon stocks may not be affected by cotton variety. Cotton variety did not have an effect on soil microbial biomass. The results indicate that while there are differences in root morphology between Bt and non-Bt cotton, these do not change the carbon turnover dynamics in the soil.

  7. Hybridizing transgenic Bt cotton with non-Bt cotton counters resistance in pink bollworm.

    Science.gov (United States)

    Wan, Peng; Xu, Dong; Cong, Shengbo; Jiang, Yuying; Huang, Yunxin; Wang, Jintao; Wu, Huaiheng; Wang, Ling; Wu, Kongming; Carrière, Yves; Mathias, Andrea; Li, Xianchun; Tabashnik, Bruce E

    2017-05-23

    Extensive cultivation of crops genetically engineered to produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has suppressed some major pests, reduced insecticide sprays, enhanced pest control by natural enemies, and increased grower profits. However, these benefits are being eroded by evolution of resistance in pests. We report a strategy for combating resistance by crossing transgenic Bt plants with conventional non-Bt plants and then crossing the resulting first-generation (F 1 ) hybrid progeny and sowing the second-generation (F 2 ) seeds. This strategy yields a random mixture within fields of three-quarters of plants that produce Bt toxin and one-quarter that does not. We hypothesized that the non-Bt plants in this mixture promote survival of susceptible insects, thereby delaying evolution of resistance. To test this hypothesis, we compared predictions from computer modeling with data monitoring pink bollworm ( Pectinophora gossypiella ) resistance to Bt toxin Cry1Ac produced by transgenic cotton in an 11-y study at 17 field sites in six provinces of China. The frequency of resistant individuals in the field increased before this strategy was widely deployed and then declined after its widespread adoption boosted the percentage of non-Bt cotton plants in the region. The correspondence between the predicted and observed outcomes implies that this strategy countered evolution of resistance. Despite the increased percentage of non-Bt cotton, suppression of pink bollworm was sustained. Unlike other resistance management tactics that require regulatory intervention, growers adopted this strategy voluntarily, apparently because of advantages that may include better performance as well as lower costs for seeds and insecticides.

  8. Applying an integrated refuge to manage western corn rootworm (Coleoptera: Chrysomelidae): effects on survival, fitness, and selection pressure.

    Science.gov (United States)

    Petzold-Maxwell, Jennifer L; Alves, Analiza P; Estes, Ronald E; Gray, Michael E; Meinke, Lance J; Shields, Elson J; Thompson, Stephen D; Tinsley, Nicholas A; Gassmann, Aaron J

    2013-10-01

    The refuge strategy can delay resistance of insect pests to transgenic maize producing toxins from Bacillus thuringiensis (Bt). This is important for the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), because of its history of adaptation to several management practices. A 2-yr study across four locations was conducted to measure the effects of integrated refuge (i.e., blended refuge) on western corn rootworm survival to adulthood, fitness characteristics, and susceptibility to Bt maize in the subsequent generation. The treatments tested in this study were as follows: a pure stand of Bt maize (event DAS-59122-7, which produces Bt toxins Cry34Ab1/Cry35Ab1), a pure stand of refuge (non-Bt maize), and two variations on an integrated refuge consisting of 94.4% Bt maize and 5.6% non-Bt maize. Within the two integrated refuge treatments, refuge seeds received a neonicotinoid insecticidal seed treatment of either 1.25 mg clothianidin per kernel or 0.25 mg thiamethoxam per kernel. Insects in the pure stand refuge treatment had greater survival to adulthood and earlier emergence than in all other treatments. Although fecundity, longevity, and head capsule width were reduced in treatments containing Bt maize for some site by year combinations, Bt maize did not have a significant effect on these factors when testing data across all sites and years. We found no differences in susceptibility of larval progeny to Bt maize in bioassays using progeny of adults collected from the four treatments.

  9. Characterization of NCAM expression and function in BT4C and BT4Cn glioma cells

    DEFF Research Database (Denmark)

    Andersson, A M; Moran, N; Gaardsvoll, H

    1991-01-01

    The neural cell adhesion molecule, NCAM, plays an important role in cell-cell adhesion. Therefore, we have studied NCAM expression in the glioma cell lines BT4C and BT4Cn. We demonstrate that the 2 cell lines differ in their metastatic ability; while BT4C cells have a very low capacity...... for producing experimental metastases, that of BT4Cn cells is high. In BT4C cells NCAM is synthesized as 4 polypeptides with Mr's of 190,000, 140,000, 115,000 and 97,000. The 140,000, 115,000 and 97,000 polypeptides are glycosylated and for the 140,000 and 115,000 polypeptides sulfatation is observed....... Conversely, no NCAM protein synthesis is observed in BT4Cn cells, even though NCAM mRNA is expressed. Thus, development of an increased metastatic capacity is accompanied by the disappearance of NCAM protein expression in this model system. The functional importance of NCAM expression was studied by a cell...

  10. Our Mother Corn.

    Science.gov (United States)

    Mathers, Sherry; And Others

    Developed to provide an understanding of the magnitude of the role of corn, referred to as Mother Corn in the cultures of the Seneca, Pawnee, and Hopi tribes, the student text provides information on the tribes' basic lifestyles and the way they grew and used corn in three different parts of the United States. The section on the origin of corn…

  11. Practice Tests for the TOEFL iBT

    CERN Document Server

    Stirling, Bruce

    2012-01-01

    Practice Tests for the TOEFL iBT contains four TOEFL tests, with answer keys. Perfect for self-study and classrooms. Each TOEFL iBT Practice Test...* reflects the design of the official TOEFL internet-based test* tests academic English-language proficiency expected of university students in the United States, Canada, Australia, New Zealand, Ireland, Scotland and England* provides extra practice before you take the official TOEFL iBT* will help you identify those areas of academic English you need to improve for a higher TOEFL iBT score* will give you an unofficial, TOEFL iBT range score within

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

    Directory of Open Access Journals (Sweden)

    Pilar Muñoz

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

  13. BT's adoption of customer centric design.

    Science.gov (United States)

    Chamberlain, Mark; Esquivel, Jacqueline; Miller, Fiona; Patmore, Jeff

    2015-01-01

    Between 2005 and 2010 BT underwent a major transformation from a company with a special section devoted to 'older and disabled consumers' to a company with an inclusive design strategy. The mainstreaming of these issues responded to a demand for better, more user-friendly communications products and growing awareness of the importance of previously marginalised consumer groups. It also took place alongside the development and publication of BS7000-6, a guide to inclusive design management. Based on several product design case studies, this paper reflects on how and why this transformation was seen as necessary for future success, and how the transformation was achieved. The evolution of BT's approach has continued since, but this paper looks back in time, and documents the transformation up to 2010 and reflects the state of the company in 2010 rather than at the time of publication. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  14. Impactos econômicos da introdução do milho Bt11 no Brasil: uma abordagem de equilíbrio geral inter-regional

    Directory of Open Access Journals (Sweden)

    Andressa Rodrigues Pavão

    2011-03-01

    Full Text Available Este trabalho analisa os impactos econômicos da adoção do milho Bt11 no Brasil, bem como as consequências da proibição deste cultivo apenas no Paraná, caso a lei estadual nº 14.162/03 entrasse em vigor. Para tal, utiliza-se um modelo computável de equilíbrio geral inter-regional, calibrado para 2001, simulando a redução de inseticida, mão de obra, combustível e lubrificantes, bem como o aumento de produtividade observado em lavouras de milho Bt11. Ao analisar a adoção nas regiões brasileiras "tecnificadas", observa-se o deslocamento de estoque de capital e mão de obra de todas as regiões para o Sul do País. Considerando-se que apenas o Paraná não adota milho Bt11, observa-se que tanto a mão de obra quanto o estoque de capital se deslocam do Sul e Sudeste para o Centro-Oeste do Brasil. Os resultados mais expressivos ocorrem no próprio estado do Paraná, onde não apenas o setor de milho, como também os setores a jusante perdem competitividade, reduzindo o nível de atividade, emprego e consumo das famílias. De forma geral, os efeitos da adoção do milho Bt11 são transmitidos ao longo da sua cadeia produtiva, gerando aumento do PIB, das exportações e do consumo das famílias, sendo mais expressivos nos setores e regiões diretamente relacionados com a cadeia de comercialização do milho, tais como os de criação animal e carnes, localizados, em sua maioria, no Sul do País.This study aims to analyze the economic impacts of the adoption of Bt11 corn in Brazil, as well as the consequences of the prohibition of the cultivation only in the Paraná state, if the state law number 14.162/03 would start to be active. For this purpose, an inter-regional general equilibrium computable model is used, gauged for 2001, simulating the reduction of insecticide, labor force, fuel and lubricants, as well as the increase in the yield observed in crops which use Bt11 corn. When the adoption of Bt11 corn in "technified" Brazilian

  15. The Halo Effect: Suppression of Pink Bollworm on Non-Bt Cotton by Bt Cotton in China

    Science.gov (United States)

    Tabashnik, Bruce E.; Huang, Minsong; Wu, Kongming

    2012-01-01

    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. PMID:22848685

  16. A case to study population dynamics of bemisia tabaci and thrips tabaci on bt and non-bt cotton genotypes

    International Nuclear Information System (INIS)

    Akram, M.; Hussain, M.; Ahmed, S.; Hafeez, F.; Farooq, M.; Arshad, M.

    2013-01-01

    Studies were conducted to investigate the performance of eight bt and five non-bt cotton genotypes against whitefly and thrips and impact of abiotic factors on the population fluctuation of these sucking pests, at cotton research station, multan, during 2010 and 2011. The results exhibited that bt genotypes found more susceptible host for the whitefly and thirps than non-bt genotypes, during the course of years of study. Among bt genotypes, maximum and minimum temperature showed significant and positive effect on whitefly population whereas relative humidity exerted negative effect during 2010. During 2011, the effect of all the factors was non significant. On cumulative basis, there was positive correlation between population of whitefly and minimum temperature. But in case of non-bt, it has negative with maximum temperature whereas relative humidity had a positive effect on whitefly population. similar trend was observed for thrips population on bt varieties during both years but on non-bt varieties only minimum temperature exerted strong positive impact on thrips population. Hierarchical regression models for whitefly and thrips revealed that minimum temperature was the most important factor (Bt and non-Bt varieties). Maximum temperature was the major contributing factor for whitefly fluctuation on bt varieties during 2010. (author)

  17. 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.

  18. Evaluating western corn rootworm (Coleoptera: Chrysomelidae) emergence and root damage in a seed mix refuge.

    Science.gov (United States)

    Murphy, A F; Ginzel, M D; Krupke, C H

    2010-02-01

    Resistance management is essential for maintaining the efficacy and long-term durability of transgenic corn engineered to control western corn rootworm (Diabrotica virgifera virgifera Le Conte). Theoretically, a refuge can be provided by growing susceptible (refuge) plants in either a separate section of the field adjacent to resistant (transgenic) plants, or as a seed mixture. We examined the effects of varying the structure of a 10 and 20% refuge between currently approved structured refuges (block or strip plantings), as well as deploying the refuge within a seed mix, on adult emergence timing and magnitude, root damage and yield. Our 2-yr field study used naturally occurring western corn rootworm populations and included seven treatments: 10 and 20% block refuge, 10 and 20% strip refuge, 10 and 20% seed mix refuge, and 100% refuge. Beetles emerging from refuge corn emerged more synchronously with those emerging from transgenic (Bacillus thuringiensis [Berliner] Bt-RW) corn in seed mix refuges when compared with block refuges. The proportion of beetles emerging from refuge plants was significantly greater in a block and strip refuge structure than in a seed mix refuge. More beetles emerged from Bt-RW corn plants when they were grown as part of a seed mix. We discuss the potential benefits and drawbacks of a seed mix refuge structure in light of these findings.

  19. TOEFL strategies a complete guide to the iBT

    CERN Document Server

    Stirling, Bruce

    2016-01-01

    TOEFL students all ask: How can I get a high TOEFL iBT score? Answer: Learn argument scoring strategies. Why? Because the TOEFL iBT recycles opinion-based and fact-based arguments for testing purposes from start to finish. In other words, the TOEFL iBT is all arguments. That's right, all arguments. If you want a high score, you need essential argument scoring strategies. That is what TOEFL STRATEGIES A COMPLETE GUIDE gives you, and more!

  20. Characterization of NCAM expression and function in BT4C and BT4Cn glioma cells

    DEFF Research Database (Denmark)

    Andersson, A M; Moran, N; Gaardsvoll, H

    1991-01-01

    . Conversely, no NCAM protein synthesis is observed in BT4Cn cells, even though NCAM mRNA is expressed. Thus, development of an increased metastatic capacity is accompanied by the disappearance of NCAM protein expression in this model system. The functional importance of NCAM expression was studied by a cell...

  1. TMD factorization and evolution at large $b_T$

    Energy Technology Data Exchange (ETDEWEB)

    Collins, John [Pennsylvania State Univ., University Park, PA (United States); Rogers, Ted [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States)

    2015-07-20

    In using transverse-momentum-dependent (TMD) parton densities and fragmentation functions, important non-perturbative information is at large transverse position $b_T$. This concerns both the TMD functions and their evolution. Fits to high energy data tend to predict too rapid evolution when extrapolated to low energies where larger values of $b_T$ dominate. I summarize a new analysis of the issues. It results in a proposal for much weaker $b_T$ dependence at large $b_T$ for the evolution kernel, while preserving the accuracy of the existing fits. The results are particularly important for using transverse-spin-dependent functions like the Sivers function.

  2. Aquatic degradation of Cry1Ab protein and decomposition dynamics of transgenic corn leaves under controlled conditions.

    Science.gov (United States)

    Böttger, Rita; Schaller, Jörg; Lintow, Sven; Gert Dudel, E

    2015-03-01

    The increasing cultivation of genetically modified corn plants (Zea mays) during the last decades is suggested as a potential risk to the environment. One of these genetically modified variety expressed the insecticidal Cry1Ab protein originating from Bacillus thuringiensis (Bt), resulting in resistance against Ostrinia nubilalis, the European corn borer. Transgenic litter material is extensively studied regarding the decomposition in soils. However, only a few field studies analyzed the fate of the Cry1Ab protein and the impact of green and senescent leaf litter from corn on the decomposition rate and related ecosystem functions in aquatic environments. Consequently, a microbial litter decomposition experiment was conducted under controlled semi-natural conditions in batch culture using two maize varieties: one variety with Cry1Ab and another one with the appertaining Iso-line as control treatment. The results showed no significant differences between the treatment with Cry1Ab and the Iso-line regarding loss of total mass in dry weight of 43% for Iso-line and 45% for Bt-corn litter, lignin content increased to 137.5% (Iso-line) and 115.7% (Bt-corn), and phenol loss decreased by 53.6% (Iso-line), 62.2% (Bt-corn) during three weeks of the experiment. At the end of the experiment Cry1Ab protein was still detected with 6% of the initial concentration. A slightly but significant lower cellulose content was found for the Cry1Ab treatment compared to the Iso-line litter at the end of the experiment. The significant higher total protein (25%) and nitrogen (25%) content in Bt corn, most likely due to the additionally expression of the transgenic protein, may increase the microbial cellulose degradation and decrease microbial lignin degradation. In conclusion a relevant year by year input of protein and therefore nitrogen rich Bt corn litter into aquatic environments may affect the balanced nutrient turnover in aquatic ecosystems. Copyright © 2014 Elsevier Inc. All rights

  3. Modification of hormonal balance in larvae of the corn borer Sesamia nonagrioides (Lepidoptera: Noctuidae) due to sublethal Bacillus thuringiensis protein ingestion.

    Science.gov (United States)

    Pérez-Hedo, Meritxell; Albajes, Ramon; Eizaguirre, Matilde

    2011-06-01

    Bacillus thuringiensis (Bt) corn, Zea mays L., is highly efficient against the corn borer Sesamia nonagrioides (Lefèbvre) (Lepidoptera: Noctuidae) when the larvae feed only on the transgenic plants. However, when they feed on Bt leaves during only part of their development, thus ingesting sublethal amounts of Bt toxins, some larvae survive. A previous study reported a prolonged development and precocious diapause induction in larvae fed on a diet with sublethal amounts of Cry1Ab protein. To determine whether these effects were accompanied by a modification of the hormonal balance, S. nonagrioides larvae were fed on sublethal amounts of Bt protein provided in Bt leaves or in the diet. The larvae that survived had higher levels of juvenile hormone (JH), whereas their level of ecdysteroids did not increase sufficiently to allow pupation, leading to a longer larval development and more larval molts. This response may be considered a defense mechanism that allows some larvae to survive toxin ingestion; it is similar the response to insecticidal toxins or viruses observed in other larvae. Changes in the hormone levels in diapausing larvae were undetectable, probably because these changes were masked by the higher level of JH in the hemolymph of diapausing larvae and because of lack of ecdysteroid titer increase, a phenomenon that is usually observed a few days before pupation in nondiapausing larvae. These results should be taken into account in the establishment of non-Bt refuges to prevent development of Bt-resistance in S. non-agrioides populations.

  4. Field evaluation of arbuscular mycorrhizal fungal colonization in Bacillus thuringiensis toxin-expressing (Bt) and non-Bt maize.

    Science.gov (United States)

    Cheeke, Tanya E; Cruzan, Mitchell B; Rosenstiel, Todd N

    2013-07-01

    The cultivation of genetically engineered Bacillus thuringiensis toxin-expressing (Bt) maize continues to increase worldwide, yet the effects of Bt crops on arbuscular mycorrhizal fungi (AMF) in soil are poorly understood. In this field experiment, we investigated the impact of seven different genotypes of Bt maize and five corresponding non-Bt parental cultivars on AMF and evaluated plant growth responses at three different physiological time points. Plants were harvested 60 days (active growth), 90 days (tasseling and starting to produce ears), and 130 days (maturity) after sowing, and data on plant growth responses and percent AMF colonization of roots at each harvest were collected. Spore abundance and diversity were also evaluated at the beginning and end of the field season to determine whether the cultivation of Bt maize had a negative effect on AMF propagules in the soil. Plant growth and AMF colonization did not differ between Bt and non-Bt maize at any harvest period, but AMF colonization was positively correlated with leaf chlorophyll content at the 130-day harvest. Cultivation of Bt maize had no effect on spore abundance and diversity in Bt versus non-Bt plots over one field season. Plot had the most significant effect on total spore counts, indicating spatial heterogeneity in the field. Although previous greenhouse studies demonstrated that AMF colonization was lower in some Bt maize lines, our field study did not yield the same results, suggesting that the cultivation of Bt maize may not have an impact on AMF in the soil ecosystem under field conditions.

  5. Coping with Ex-ante Regulations for Planting Bt Maize: The Portuguese Experience

    NARCIS (Netherlands)

    Skevas, T.; Wesseler, J.H.H.; Fevereiro, P.

    2009-01-01

    This article investigates the attitude and practices of Bt and non-Bt maize farmers in Portugal. Thirty-seven Bt maize farmers were interviewed, representing 22.5% of the total number of Bt maize notifications in the country and 31.5% of the total area planted with Bt maize in 2007. Additionally, 66

  6. Immunotoxicological Evaluation of Corn Genetically Modified with Bacillus thuringiensis Cry1Ah Gene by a 30-Day Feeding Study in BALB/c Mice

    Science.gov (United States)

    Song, Yan; Liang, Chunlai; Wang, Wei; Fang, Jin; Sun, Nana; Jia, Xudong; Li, Ning

    2014-01-01

    This study was to investigate the immunotoxicological potential of corn genetically modified (GM) with Bacillus thuringiensis (Bt) Cry1Ah gene in BALB/c mice. Female BALB/c mice were randomly assigned to one of the four groups: the negative control group, the parental corn group, the GM corn group and the positive control group with 10 mice per group. Mice in the GM corn group and the parental corn group were fed with diets containing 70% corresponding corn for 30 days. Mice in the negative control group and the positive control group were fed with AIN93G diet, administered with saline or 200 mg/kg of cyclophosphamide (CY) via intraperitoneal injection 24 h before the termination of the study, respectively. At the end of the study, the immunotoxicological effects of the GM corn were evaluated through immunopathology parameters including body and organ weights, hematology and clinical chemistry parameters, histological examination, peripheral blood lymphocytes phenotype; humoral immunity including antibody plaque-forming cell, serum immunoglobulin, cytokine and half hemolysis value; cellular immunity such as mitogen-induced splenocyte proliferation, cytotoxic T-lymphocyte reaction, delayed-type hypersensitivity reaction; non-specific immunity including phagocytic activities of phagocytes, natural killer cell activity. A single dose of cyclophosphamide (200 mg/kg bw) was found to have significant adverse effects on immunopathology, cellular immunity, and humoral immunity in mice. The corn genetically modified with Bt Cry1Ah gene is considered consistent with the parental corn in terms of immunopathology, humoral immunity, cellular immunity and non-specific immunity. No adverse immunotoxicological effects of GM corn with Bt Cry1Ah gene were found when feeding mice for 30 days. PMID:24520311

  7. Immunotoxicological evaluation of corn genetically modified with Bacillus thuringiensis Cry1Ah gene by a 30-day feeding study in BALB/c mice.

    Directory of Open Access Journals (Sweden)

    Yan Song

    Full Text Available This study was to investigate the immunotoxicological potential of corn genetically modified (GM with Bacillus thuringiensis (Bt Cry1Ah gene in BALB/c mice. Female BALB/c mice were randomly assigned to one of the four groups: the negative control group, the parental corn group, the GM corn group and the positive control group with 10 mice per group. Mice in the GM corn group and the parental corn group were fed with diets containing 70% corresponding corn for 30 days. Mice in the negative control group and the positive control group were fed with AIN93G diet, administered with saline or 200 mg/kg of cyclophosphamide (CY via intraperitoneal injection 24 h before the termination of the study, respectively. At the end of the study, the immunotoxicological effects of the GM corn were evaluated through immunopathology parameters including body and organ weights, hematology and clinical chemistry parameters, histological examination, peripheral blood lymphocytes phenotype; humoral immunity including antibody plaque-forming cell, serum immunoglobulin, cytokine and half hemolysis value; cellular immunity such as mitogen-induced splenocyte proliferation, cytotoxic T-lymphocyte reaction, delayed-type hypersensitivity reaction; non-specific immunity including phagocytic activities of phagocytes, natural killer cell activity. A single dose of cyclophosphamide (200 mg/kg bw was found to have significant adverse effects on immunopathology, cellular immunity, and humoral immunity in mice. The corn genetically modified with Bt Cry1Ah gene is considered consistent with the parental corn in terms of immunopathology, humoral immunity, cellular immunity and non-specific immunity. No adverse immunotoxicological effects of GM corn with Bt Cry1Ah gene were found when feeding mice for 30 days.

  8. Can pyramids and seed mixtures delay resistance to Bt crops?

    Science.gov (United States)

    The primary strategy for delaying evolution of pest resistance to transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt) entails refuges of plants that do not produce Bt toxins and thus allow survival of susceptible pests. Recent advances include using refuges together...

  9. Leaf tissue assay for lepidopteran pests of Bt cotton

    Science.gov (United States)

    Laboratory measurements of susceptibility to Bt toxins can be a poor indicator of the ability of an insect to survive on transgenic crops. We investigated the potential of using cotton leaf tissue for evaluating heliothine susceptibilities to two dual-gene Bt cottons. A preliminary study was conduct...

  10. Assessing the potential economic impact of Bacillus thuringiensis (Bt ...

    African Journals Online (AJOL)

    The Insect Resistant Maize for Africa (IRMA) project is currently developing Bt maize for Kenya. So far, Bt genes with resistance to Chilo partellus, Chilo orichalcociliellus, Eldana sacharina, and Sesamia calamistis, four of the five major stemborers were successfully incorporated into elite CIMMYT maize inbred line ...

  11. Evaluation of stem borer resistance management strategies for Bt ...

    African Journals Online (AJOL)

    Stem borers are the major insect pests of maize in Kenya. The use of Bacillus thuringiensis (Bt) technology is an effective way of controlling lepidopteran pests. However, the likelihood of development of resistance to the Bt toxins by the target stem borer species is a concern. Forages, sorghum and maize varieties were ...

  12. Evaluation of stem borer resistance management strategies for Bt ...

    African Journals Online (AJOL)

    GREGORY

    2011-06-01

    Jun 1, 2011 ... Stem borers are the major insect pests of maize in Kenya. The use of Bacillus thuringiensis (Bt) technology is an effective way of controlling lepidopteran pests. However, the likelihood of development of resistance to the Bt toxins by the target stem borer species is a concern. Forages, sorghum and maize ...

  13. Comparison of rhizosphere properties as affected by different Bt- and non-Bt-cotton (Gossypium hirsutum L.) genotypes and fertilization.

    Science.gov (United States)

    Ahamd, Maqshoof; Abbasi, Waleed Mumtaz; Jamil, Moazzam; Iqbal, Muhammad; Hussain, Azhar; Akhtar, Muhammad Fakhar-U-Zaman; Nazli, Farheen

    2017-06-01

    Incorporation of genetically modified crops in the cropping system raises the need for studying the effect of these crops on the soil ecosystem. The current study aimed to compare the effect of Bacillus thuringiensis (Bt)- and non-Bt-cotton (Gossypium hirsutum L.) genotypes on rhizosphere properties under fertilized and unfertilized soil conditions. One non-Bt-cotton (IUB 75) and four Bt-cotton varieties (IUB-222, MM-58, IUB-13, FH-142) were sown in a Randomized Complete Block Design (RCBD) in a factorial fashion with three replications under unfertilized (T1) and fertilized (T2 at NPK 310-170-110 kg ha -1 ) soil conditions. The culturable soil bacterial population was recorded at flowering, boll opening, and harvesting stages, while other rhizosphere biological and chemical properties were recorded at harvesting. Results revealed that Bt-cotton genotypes IUB-222 and FH-142 showed significantly higher rhizosphere total nitrogen, NH 4 + -N, available phosphorus, and available potassium. Total organic carbon and microbial biomass carbon was also maximum in the rhizosphere of IUB-222 under fertilized conditions. Similarly, bacterial population (CFU g -1 ) at flowering stage and at harvesting was significantly higher in the rhizosphere of IUB-222 as compared to non-Bt- (IUB-75) and other Bt-cotton genotypes under same growth conditions. It showed that Bt genotypes can help in maintaining soil macronutrients (total nitrogen, available phosphorus, and available potassium) under proper nutrient management. Moreover, Bt-cotton genotypes seem to strengthen certain biological properties of the soil, thus increasing the growth and yield capability, maintaining available nutrients in the soil as compared to non-Bt cotton, while no harmful effects of Bt cotton on soil properties was detected.

  14. Effectiveness of Microbial and Chemical Insecticides for Supplemental Control of Bollworm on Bt and Non-Bt Cottons.

    Science.gov (United States)

    Little, N S; Luttrell, R G; Allen, K C; Perera, O P; Parys, K A

    2017-06-01

    Laboratory and field experiments were conducted to determine the effectiveness of microbial and chemical insecticides for supplemental control of bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), on non-Bt (DP1441RF) and Bt (DP1321B2RF) cottons. Neonate and 3rd instar larvae survival was evaluated on leaf tissue treated with microbial and chemical insecticides including a commercial formulation of Bacillus thuringiensis (Dipel), a Heliothis (Helicoverpa) nuclear polyhedrosis virus (NPV; Gemstar), λ-cyhalothrin (Karate Z), and chlorantraniliprole (Prevathon). Residual activity of insecticides was measured in a small plot field experiment. The performance of microbial insecticides, with the exception of a mid-rate of Dipel with neonate larvae, was comparable with that of chemical treatments on non-Bt cotton leaves with regard to 1st and 3rd instar bollworm mortality at 10 d and pupal eclosion at 20-d post treatment. Production-level field evaluations of supplemental bollworm control in non-Bt and Bt cottons with NPV, λ-cyhalothrin, and chlorantraniliprole were also conducted. During both years of the field study, all chemical and microbial treatments were successful in suppressing bollworm larval densities in non-Bt cotton below economic threshold levels. Overall, net returns above bollworm control, regardless of treatment, were negatively correlated with larval abundance and plant damage. In addition, there was no economic benefit for supplemental control of bollworms in Bt cotton at the larval densities observed during this study. These data provide benchmark comparisons for insect resistance management with microbial and chemical insecticides in Bt and non-Bt cottons and strategic optimization of the need to spray non-Bt and Bt cotton in IRM programs. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.

  15. Novel Vip3A Bacillus thuringiensis (Bt) maize approaches high-dose efficacy against Helicoverpa zea (Lepidoptera: Noctuidae) under field conditions: Implications for resistance management.

    Science.gov (United States)

    Burkness, Eric C; Dively, Galen; Patton, Terry; Morey, Amy C; Hutchison, William D

    2010-01-01

    Sweet corn, Zea mays L., transformed to express a novel vegetative insecticidal protein, Vip3A (event MIR162, Syngenta Seeds, Inc..), produced by the bacterium, Bacillus thuringiensis (Bt), was evaluated over four field seasons in Maryland and two field seasons in Minnesota for efficacy against the corn earworm, Helicoverpa zea (Boddie). Hybrids expressing the Vip3A protein and pyramided in hybrids also expressing the Cry1Ab Bt protein (event Bt11, ATTRIBUTE(®), Syngenta Seeds, Inc.) were compared to hybrids expressing only Cry1Ab or to genetically similar non-Bt hybrids each year. In addition to H. zea efficacy, results for Ostrinia nubilalis (Hübner) and Spodoptera frugiperda (J.E. Smith) are presented. Over all years and locations, the non-Bt hybrids, without insecticide protection, averaged between 43 and 100% ears infested with a range of 0.24 to 1.74 H. zea larvae per ear. By comparison, in the pyramided Vip3A x Cry1Ab hybrids, no larvae were found and only minimal kernel damage (likely due to other insect pests) was recorded. Hybrids expressing only Cry1Ab incurred a moderate level of H. zea feeding damage, with surviving larvae mostly limited to the first or second instar as a result of previously documented growth inhibition from Cry1Ab. These results suggest that the Vip3A protein, pyramided with Cry1Ab, appears to provide the first "high-dose" under field conditions and will be valuable for ongoing resistance management.

  16. Biosafety assessment of transgenic Bt cotton on model animals

    Directory of Open Access Journals (Sweden)

    Sadia Bano

    2016-05-01

    Full Text Available Abstract Background: To know the effects of transgenic crops on soil microorganisms, animals and other expected hazards due to the introduction of GM crops into the environment is critical both scientifically and environmentally. The work was conducted to study the effect of insecticidal Bt protein on Rats and Earthworms. Methods: For this purpose, animals like rat and soil organisms like Earthworm were selected. Rats were selected on the basis of its 95% homology on genomic, cellular and enzymatic level with human while earthworm were preferred on the basis of their direct contact with soil to evaluate the impact of Bt (Cry1AC crop field soil on earthworm, secreted by root exudates of Bt cotton. Several physical, molecular, biochemical and histological analyses were performed on both Rats/Earthworms fed on standard diet (control group as well containing Bt protein (experimental group. Results: Molecular analyses such as immune Dot blot, SDS-PAGE, ELISA and PCR, confirmed the absence of Cry1Ac protein in blood and urine samples of rats, which were fed with Bt protein in their diet. Furthermore, histological studies showed that there was no difference in cellular architecture in liver, heart, kidney and intestine of Bt and non-Bt diet fed rats. To see the effect of Bt on earthworm two different groups were studied, one with transgenic plant field soil supplemented with grinded leaves of cotton and second group with non-Bt field soil. Conclusions: No lethal effects of transgenic Bt protein on the survival of earthworm and rats were observed. Bradford assay, Dipstick assay ELISA demonstrated the absence of Cry1Ac protein in the mid-gut epithelial tissue of earthworm. The results of present study will be helpful in successful deployment and commercial release of genetically modified crop in Pakistan.

  17. Biodiversity of ground beetles (Coleoptera: Carabidae) in genetically modified (Bt) and conventional (non-Bt) potato fields in Bulgaria

    Czech Academy of Sciences Publication Activity Database

    Kalushkov, P.; Gueorguiev, B.; Spitzer, L.; Nedvěd, Oldřich

    2009-01-01

    Roč. 23, č. 3 (2009), s. 1346-1350 ISSN 1310-2818 Grant - others:Bulgarian National Research Fund(BG) B-1508; Bulgarian National Research Fund(BG) B-1105 Institutional research plan: CEZ:AV0Z50070508 Keywords : ground beetles * Bt potatoes * non-Bt potatoes Subject RIV: EH - Ecology, Behaviour Impact factor: 0.291, year: 2009

  18. Study of effects of Bt maize (Zea mays) events on Lepidoptera Ostrinia nubilalis, Sesamia nonagrioidesin southwestern France.

    Science.gov (United States)

    Folcher, L; Eychenne, N; Weissenberger, A; Jarry, M; Regnault-Roger, C; Delos, M

    2006-01-01

    Crops of maize (Zea mays L.) were conducted in southwestern France with GMO (Genetic Modified Organism) vs isogenetic varieties in order to verify the control of European Corn Borer (ECB) Ostrinia nubilalis (Hübner) and the Corn Stalk Borer (CBS) Sesamia nonagrioides (Lefevbre) by GMO in field conditions. The bioassays were carried out in 1998 and 1999 before moratorium, then in 2005. Experiments involved respectively 18, 12 and 19 fields cultivated with Furio/Furio cb (GMO), Cecilia/ Elgina (GMO) and PR33P66/PR33P67 (GMO) varieties. These transgenic events expressed Cry1A(b) protein (Bt maize). Plants were noted for insect infestation assessment (number of larvae in stalks and ears per plant). Statistical tests used t-test on couple of plots. Results showed a significant difference in the density of both ECB and CBS between control and the two transgenic events. The two transgenic events acted differently. The control of the two Bt events on the two pests were differentiated and discussed. These experiments underlined the importance of field evaluation for testing real effects of transgenic events on crop according the environmental context.

  19. TRANSGENIC PLANTS - INSECTICIDAL TOXIN IN ROOT EXUDATES FROM BT CORN. (R826107)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  20. Study on radioimmunoassay of Bt Cry1Ac protein

    International Nuclear Information System (INIS)

    Pan Jiarong; Zhang Wei; Lin Min; Zhang Jie; Qiao Yanhong

    2006-01-01

    Bt Cry1Ac protein was extracted from incubation of Bacillus thuringiensis HD-73, and cutting into more specific protein segment with high insect-resistance. High-affinity multi-colonial antibodies of Bt Cry1 Ac protein were obtained after injected it into New Zealand rabbits. By 125 I labeling of Bt Cry1 Ac protein, a RIA kit was established. In this method, centrifuge for separation was not necessary due to the use of magnetic micro-particle and the specifications of the kit were found equal to those of imported ELISA. (authors)

  1. Harmonia axyridis (Coleoptera: Coccinellidae exhibits no preference between Bt and non-Bt maize fed Spodoptera frugiperda (Lepidoptera: Noctuidae.

    Directory of Open Access Journals (Sweden)

    Carla C Dutra

    Full Text Available A recent shift in managing insect resistance to genetically engineered (GE maize consists of mixing non-GE seed with GE seed known as "refuge in a bag", which increases the likelihood of predators encountering both prey fed Bt and prey fed non-Bt maize. We therefore conducted laboratory choice-test feeding studies to determine if a predator, Harmonia axyridis, shows any preference between prey fed Bt and non-Bt maize leaves. The prey species was Spodoptera frugiperda, which were fed Bt maize (MON-810, expressing the single Cry1Ab protein, or non-Bt maize. The predators were third instar larvae and female adults of H. axyridis. Individual predators were offered Bt and non-Bt fed prey larvae that had fed for 24, 48 or 72 h. Ten and 15 larvae of each prey type were offered to third instar and adult predators, respectively. Observations of arenas were conducted at 1, 2, 3, 6, 15 and 24 h after the start of the experiment to determine the number and type of prey eaten by each individual predator. Prey larvae that fed on non-Bt leaves were significantly larger than larvae fed Bt leaves. Both predator stages had eaten nearly all the prey by the end of the experiment. However, in all combinations of predator stage and prey age, the number of each prey type consumed did not differ significantly. ELISA measurements confirmed the presence of Cry1Ab in leaf tissue (23-33 µg/g dry weight and S. frugiperda (2.1-2.2 µg/g, while mean concentrations in H. axyridis were very low (0.01-0.2 µg/g. These results confirm the predatory status of H. axyridis on S. frugiperda and that both H. axyridis adults and larvae show no preference between prey types. The lack of preference between Bt-fed and non-Bt-fed prey should act in favor of insect resistance management strategies using mixtures of GE and non-GE maize seed.

  2. Effects of ensiling of Bacillus thuringiensis (Bt) maize (MON810) on ...

    African Journals Online (AJOL)

    The study investigated the degradation of the Bt protein (Cry1Ab) in Bt maize during ensiling and chemical composition of the silage. Two laboratory studies were conducted at the University of Fort Hare. One Bacillus thuringiensis (Bt) maize cultivar (DKC80-12B) and its isoline (DKC80-10) in the 2008/2009 study and two Bt ...

  3. Evidence for Field-Evolved Resistance of Striacosta albicosta (Lepidoptera: Noctuidae) to Cry1F Bacillus thuringiensis Protein and Transgenic Corn Hybrids in Ontario, Canada.

    Science.gov (United States)

    Smith, J L; Lepping, M D; Rule, D M; Farhan, Y; Schaafsma, A W

    2017-10-01

    Western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a pest of corn (Zea mays L.) that has recently expanded its range into Ontario, Canada. Control of S. albicosta damage to corn hybrids containing event TC1507-expressing Cry1F Bacillus thuringiensis protein alone or pyramided with event MON 89034 expressing Cry1A.105 and Cry2Ab2 Bt proteins was tested in 2011-2015 in Ontario in small- and large-scale field plots with natural infestation. In 2011, significantly lower incidence and severity of kernel damage was sustained by Cry1F × Cry1A.105 + Cry2Ab2 corn compared with a non-Bt near-isogenic hybrid. However, from 2012 to 2015, there was no difference in incidence or severity of damage comparing non-Bt hybrids with Cry1F hybrids alone or pyramided with Cry1A.105 and Cry2Ab2 planted as a pure stand or with an integrated refuge (95% Bt: 5% non-Bt seeds). In 2015, neonate larvae derived from Ontario field-collections were tested in concentration-response diet-overlay bioassays with lyophilized Cry1F protein at concentrations up to 75 µg cm-2. The concentrations at which mortality of 50% (LC50) of the collections occurred ranged from approximately 10 µg cm-2 (F0) to >28 µg cm-2 (F1) in a 7-d bioassay, indicating relative insensitivity to Cry1F. Results from field experiments, laboratory bioassays, and the history of exposure to Cry1F in corn show that S. albicosta in Ontario are not controlled by Cry1F-expressing corn hybrids and provide evidence for the conclusion that the evolution of resistance to Cry1F has occurred. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Developing Analytic Rating Guides for "TOEFL iBT"® Integrated Speaking Tasks. "TOEFL iBT"® Research Report, TOEFL iBT-20. ETS Research Report. RR-13-13

    Science.gov (United States)

    Jamieson, Joan; Poonpon, Kornwipa

    2013-01-01

    Research and development of a new type of scoring rubric for the integrated speaking tasks of "TOEFL iBT"® are described. These "analytic rating guides" could be helpful if tasks modeled after those in TOEFL iBT were used for formative assessment, a purpose which is different from TOEFL iBT's primary use for admission…

  5. Comparative diversity of arthropods on Bt maize and non-Bt maize in two different cropping systems in South Africa.

    Science.gov (United States)

    Truter, J; Van Hamburg, H; Van Den Berg, J

    2014-02-01

    The biodiversity of an agroecosystem is not only important for its intrinsic value but also because it influences ecological functions that are vital for crop production in sustainable agricultural systems and the surrounding environment. A concern about genetically modified (GM) crops is the potential negative impact that such crops could have on diversity and abundance of nontarget organisms, and subsequently on ecosystem functions. Therefore, it is essential to assess the potential environmental risk of the release of a GM crop and to study its effect on species assemblages within that ecosystem. Assessment of the impact of Bt maize on the environment is hampered by the lack of basic checklists of species present in maize agroecosystems. The aims of the study were to compile a checklist of arthropods that occur on maize in South Africa and to compare the diversity and abundance of arthropods and functional groups on Bt maize and non-Bt maize. Collections of arthropods were carried out during two growing seasons on Bt maize and non-Bt maize plants at two localities. Three maize fields were sampled per locality during each season. Twenty plants, each of Bt maize and non-Bt maize, were randomly selected from the fields at each site. The arthropods collected during this study were classified to morphospecies level and grouped into the following functional groups: detritivores, herbivores, predators, and parasitoids. Based on feeding strategy, herbivores and predators were further divided into sucking herbivores or predators (piercing-sucking mouthparts) and chewing herbivores or predators (chewing mouthparts). A total of 8,771 arthropod individuals, comprising 288 morphospecies and presenting 20 orders, were collected. Results from this short-term study indicated that abundance and diversity of arthropods in maize and the different functional guilds were not significantly affected by Bt maize, either in terms of diversity or abundance.

  6. CORN, LP Goldfield Approval

    Science.gov (United States)

    This November 19, 2015 letter from EPA approves the petition from CORN, LP, Goldfield facility, regarding non-grandfathered ethanol produced through a dry mill process, qualifying under the Clean Air Act for renewable fuel (D-code 6) RINs under the RFS pro

  7. BIOFUEL FROM CORN STOVER

    Directory of Open Access Journals (Sweden)

    Ljiljanka Tomerlin

    2003-12-01

    Full Text Available This paper deals with production of ethyl alcohol (biofuel from corn stover acid hydrolysate by yeasts, respectively at Pichia stipitis y-7124 and Pachysolen tannophilus y-2460 and Candida shehatae y-12856. Since moist corn stover (Hybryds 619 is proving to decomposition by phyllospheric microflora. It was (conserved spattered individually by microbicids: Busan-90, Izosan-G and formalin. In form of prismatic bales, it was left in the open air during 6 months (Octobar - March. At the beginning and after 6 months the microbiological control was carried out. The only one unspattered (control and three stover corn bals being individually spattered by microbicids were fragmented and cooked with sulfur acid. The obtained four acid hydrolysates are complex substratums, containing, apart from the sugars (about 11 g dm-3 pentosa and about 5.4 g dm-3 hexose, decomposite components as lignin, caramel sugars and uronic acids. By controlling the activity of the mentioned yeasts it was confirmed that yeasts Pichia stipitis y-7124 obtained best capability of ethyl alcohol production from corn stover acid hydrolysate at 0.23 vol. % to 0.49 vol. %.

  8. Assessment of Inheritance and Fitness Costs Associated with Field-Evolved Resistance to Cry3Bb1 Maize by Western Corn Rootworm

    Directory of Open Access Journals (Sweden)

    Aubrey R. Paolino

    2017-05-01

    Full Text Available The western corn rootworm, Diabrotica virgifera virgifera LeConte, is among the most serious insect pests of maize in North America. One strategy used to manage this pest is transgenic maize that produces one or more crystalline (Cry toxins derived from the bacterium Bacillus thuringiensis (Bt. To delay Bt resistance by insect pests, refuges of non-Bt maize are grown in conjunction with Bt maize. Two factors influencing the success of the refuge strategy to delay resistance are the inheritance of resistance and fitness costs, with greater delays in resistance expected when inheritance of resistance is recessive and fitness costs are present. We measured inheritance and fitness costs of resistance for two strains of western corn rootworm with field-evolved resistance to Cry3Bb1 maize. Plant-based and diet-based bioassays revealed that the inheritance of resistance was non-recessive. In a greenhouse experiment, in which larvae were reared on whole maize plants in field soil, no fitness costs of resistance were detected. In a laboratory experiment, in which larvae experienced intraspecific and interspecific competition for food, a fitness cost of delayed larval development was identified, however, no other fitness costs were found. These findings of non-recessive inheritance of resistance and minimal fitness costs, highlight the potential for the rapid evolution of resistance to Cry3Bb1 maize by western corn rootworm, and may help to improve resistance management strategies for this pest.

  9. Assessment of Inheritance and Fitness Costs Associated with Field-Evolved Resistance to Cry3Bb1 Maize by Western Corn Rootworm.

    Science.gov (United States)

    Paolino, Aubrey R; Gassmann, Aaron J

    2017-05-11

    The western corn rootworm, Diabrotica virgifera virgifera LeConte, is among the most serious insect pests of maize in North America. One strategy used to manage this pest is transgenic maize that produces one or more crystalline (Cry) toxins derived from the bacterium Bacillus thuringiensis (Bt). To delay Bt resistance by insect pests, refuges of non-Bt maize are grown in conjunction with Bt maize. Two factors influencing the success of the refuge strategy to delay resistance are the inheritance of resistance and fitness costs, with greater delays in resistance expected when inheritance of resistance is recessive and fitness costs are present. We measured inheritance and fitness costs of resistance for two strains of western corn rootworm with field-evolved resistance to Cry3Bb1 maize. Plant-based and diet-based bioassays revealed that the inheritance of resistance was non-recessive. In a greenhouse experiment, in which larvae were reared on whole maize plants in field soil, no fitness costs of resistance were detected. In a laboratory experiment, in which larvae experienced intraspecific and interspecific competition for food, a fitness cost of delayed larval development was identified, however, no other fitness costs were found. These findings of non-recessive inheritance of resistance and minimal fitness costs, highlight the potential for the rapid evolution of resistance to Cry3Bb1 maize by western corn rootworm, and may help to improve resistance management strategies for this pest.

  10. Transgenic Bacillus thuringiensis (Bt rice is safer to aquatic ecosystems than its non-transgenic counterpart.

    Directory of Open Access Journals (Sweden)

    Guangsheng Li

    Full Text Available Rice lines genetically modified with the crystal toxin genes from Bacillus thuringiensis (Bt have experienced rapid development, with biosafety certificates for two Bt rice lines issued in 2009. There has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. Some studies confirmed that Bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in Bt rice to control non-lepidopteran pests. In this study, we assessed the environmental effects of two Bt rice lines expressing either the cry1Ab/1Ac or cry2A genes, respectively, by using zooplanktons as indicator species under normal field management practices using pesticides when required. In the whole rice growing season, non-Bt rice was sprayed 5 times while Bt rice was sprayed 2 times, which ensured both rice achieved a normal yield. Field investigations showed that rice type (Bt and non-Bt significantly influenced zooplankton abundance and diversity, which were up to 95% and 80% lower in non-Bt rice fields than Bt rice fields. Laboratory rearing showed that water from non-Bt rice fields was significantly less suitable for the survival and reproduction of Daphnia magna and Paramecium caudatum in comparison with water from Bt rice fields. Higher pesticide residues were detected in the water from non-Bt than Bt rice fields, accounting for the bad performance of zooplankton in non-Bt field water. Our results demonstrate that Bt rice is safer to aquatic ecosystems than non-Bt rice, and its commercialization will be beneficial for biodiversity restoration in rice-based ecosystems.

  11. Open Services Innovation: The Case of BT in the UK

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Yamasaki Sato

    2014-06-01

    Full Text Available Open innovation was conceptualised by Chesbrough (2003, p. 34 using cases from the ICT (Information and Communications Technologies sector, more specifically equipment and component suppliers such as Lucent, IBM and Intel. Subsequently, the vast majority of the case studies in open innovation emphasised innovation processes in goods-based firms, not in service firms. Open systems innovation was well known in the telecommunications industry well before Chesbrough’s conceptualisation of open innovation. However, subsequent research has not paid much attention on its adoption by incumbent telecommunications operators. This paper investigates how open innovation was adopted by the incumbent telecommunications operator BT in the UK, using the case study as the research method. BT used open innovation as a management injunction to systematise innovation under a common framework to leverage and integrate technology and knowledge in order to address customer needs, and to change the way of thinking about innovation within BT.

  12. Scoring Strategies for the TOEFL iBT A Complete Guide

    CERN Document Server

    Stirling, Bruce

    2012-01-01

    TOEFL students all ask: How can I get a high TOEFL iBT score? Answer: Learn argument scoring strategies. Why? Because the TOEFL iBT recycles opinion-based and fact-based arguments for testing purposes from start to finish. In other words, the TOEFL iBT is all arguments. That's right, all arguments. If you want a high score, you need essential argument scoring strategies. That is what Scoring Strategies for the TOEFL iBT gives you, and more!. TEST-PROVEN STRATEGIES. Learn essential TOEFL iBT scoring strategies developed in American university classrooms and proven successful on the TOEFL iBT. R

  13. Bt rice in China - focusing the nontarget risk assessment.

    Science.gov (United States)

    Li, Yunhe; Zhang, Qingling; Liu, Qingsong; Meissle, Michael; Yang, Yan; Wang, Yanan; Hua, Hongxia; Chen, Xiuping; Peng, Yufa; Romeis, Jörg

    2017-10-01

    Bt rice can control yield losses caused by lepidopteran pests but may also harm nontarget species and reduce important ecosystem services. A comprehensive data set on herbivores, natural enemies, and their interactions in Chinese rice fields was compiled. This together with an analysis of the Cry protein content in arthropods collected from Bt rice in China indicated which nontarget species are most exposed to the insecticidal protein and should be the focus of regulatory risk assessment. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  14. Detection limits of the strip test and PCR for genetically modified corn in Brazil.

    Science.gov (United States)

    Nascimento, V E; Von Pinho, É V R; Von Pinho, R G; do Nascimento, A D

    2012-08-16

    Brazilian legislation establishes a labeling limit for products that contain more than 1% material from genetically modified organisms (GMOs). We assessed the sensitivity of the lateral flow strip test in detection of the GMO corn varieties Bt11 and MON810 and the specificity and sensitivity of PCR techniques for their detection. For the strip test, the GMO seeds were mixed with conventional seeds at levels of 0.2, 0.4 and 0.8% for Bt11, and 0.4, 0.8 and 1.6% for MON810. Three different methodologies were assessed and whole seeds, their endosperm and embryonic axis were used. For the PCR technique, the GMO seeds of each of the two varieties were mixed with conventional seeds at levels of 20, 10, 5, 2, 1, and 0.5%. The seeds were ground and the DNA extracted. For detection of the GMO material, specific primers were used for MON810 and Bt11 and maize zein as an endogenous control. The sensitivity of the strip test varied for both maize varieties and methodologies. The test was positive for Bt11 only at 0.8%, in contrast with the detection limit of 0.4% indicated by the manufacturer. In the multiplex PCR, the primers proved to be specific for the different varieties. These varieties were detected in samples with one GMO seed in 100. Thus, this technique proved to be efficient in detecting contaminations equal to or greater than 1%.

  15. Densification characteristics of corn cobs

    Energy Technology Data Exchange (ETDEWEB)

    Kaliyan, Nalladurai; Morey, R. Vance [Department of Bioproducts and Biosystems Engineering, University of Minnesota, 1390 Eckles Avenue, St. Paul, MN 55108 (United States)

    2010-05-15

    Corn cobs are potential feedstocks for producing heat, power, fuels, and chemicals. Densification of corn cobs into briquettes/pellets would improve their bulk handling, transportation, and storage properties. In this study, densification characteristics of corn cobs were studied using a uniaxial piston-cylinder densification apparatus. With a maximum compression pressure of 150 MPa, effects of particle size (0.85 and 2.81 mm), moisture content (10 and 20% w.b.), and preheating temperature (25 and 85 C) on the density and durability of the corn cob briquettes (with diameter of about 19.0 mm) were studied. It was found that the durability (measured using ASABE tumbling can method) of corn cob briquettes made at 25 C was 0%. At both particle sizes, preheating of corn cob grinds with about 10% (w.b.) moisture content to 85 C produced briquettes with a unit density of > 1100 kg m{sup -3} and durability of about 90%. (author)

  16. Regulation of the seasonal population patterns of Helicoverpa armigera moths by Bt cotton planting.

    Science.gov (United States)

    Gao, Yu-Lin; Feng, Hong-Qiang; Wu, Kong-Ming

    2010-08-01

    Transgenic cotton expressing the Bacillus thuringiensis (Bt) Cry1Ac toxin has been commercially cultivated in China since 1997, and by 2000 Bt cotton had almost completely replaced non-transgenic cotton cultivars. To evaluate the impact of Bt cotton planting on the seasonal population patterns of cotton bollworm, Helicoverpa armigera, the dynamics of H. armigera moths were monitored with light traps from four locations (Xiajin, Linqing and Dingtao of Shandong Province; Guantao of Hebei Province) in high Bt density region and five locations (Anci and Xinji of Hebei Province; Dancheng and Fengqiu of Henan Province; Gaomi of Shandong Province) in low Bt density region from 1996 to 2008. A negative correlation was found between moth densities of H. armigera and the planting years of Bt cotton in both high and low Bt density areas. These data indicate that the moth population density of H. armigera was reduced with the introduction of Bt cotton in northern China. Three generations of moths occurred between early June and late September in the cotton regions. Interestingly, second-generation moths decreased and seemed to vanish in recent years in high Bt density region, but this tendency was not found in low Bt density region. The data suggest that the planting of Bt cotton in high Bt density region was effective in controlling the population density of second-generation moths. Furthermore, the seasonal change of moth patterns associated with Bt cotton planting may regulate the regional occurrence and population development of this migratory insect.

  17. Gene pyramiding as a Bt resistance management strategy: How ...

    African Journals Online (AJOL)

    Reports on the emergence of insect resistance to Bacillus thuringiensis delta endotoxins have raised doubts on the sustainability of Bt-toxin based pest management technologies. Corporate industry has responded to this challenge with innovations that include gene pyramiding among others. Pyramiding entails stacking ...

  18. Insect communities on maize expressing a Bt-toxin

    Czech Academy of Sciences Publication Activity Database

    Habuštová, Oxana; Sehnal, František; Hussein, Hany

    2005-01-01

    Roč. 1, - (2005), s. 9-11 ISSN 1335-258X R&D Projects: GA AV ČR(CZ) KJB6007304 Institutional research plan: CEZ:AV0Z50070508 Keywords : GMO * arthropod communities * Bt maize Subject RIV: EH - Ecology, Behaviour

  19. Management practices to control premature senescence in bt cotton

    Science.gov (United States)

    Commercial cultivation of Bt cotton produced higher boll load which led to stiff inter-organal competition for photosynthates resulting in early cessation of growth (premature senescence) due to more availability of sink and less sources. To overcome this problem field experiment was conducted durin...

  20. Evaluation of stem borer resistance management strategies for Bt ...

    African Journals Online (AJOL)

    GREGORY

    2011-06-01

    Jun 1, 2011 ... However, for successful management of a refugia strategy, strict stewardship is required from appropriate government or community institutions. Key words: Refugia, cost-benefit analysis, Bt-maize, insect pest resistance management. INTRODUCTION. Maize is the leading staple food in the world with two-.

  1. Evaluation of bioassays for testing Bt sweetpotato events against ...

    African Journals Online (AJOL)

    Sweetpotato weevil (Cylas puncticollis) Boheman is a serious pest throughout Sub-Saharan Africa region and is a big threat to sweetpotato cultivation. Ten transgenic sweetpotato events expressing Cry7Aa1, Cry3Ca1, and ET33-34 proteins from Bacillus thuringiensis (Bt) were evaluated for resistance against C.

  2. Reproduction of root knot nematode (Meloidogyne incognita) on Bt ...

    African Journals Online (AJOL)

    SARAH

    2013-09-30

    Sep 30, 2013 ... ABSTRACT. Objective: The sedentary endoparasite Meloidogyne incognita is an important plant parasitic nematode that infects cotton causing significant yield losses. The objective of this study was to evaluate reproduction of M. incognita in Bt cotton (06Z604D), isoline (99M03) and HART 89M (local ...

  3. Assessment of biological and biochemical indicators in soil under transgenic Bt and non-Bt cotton crop in a sub-tropical environment.

    Science.gov (United States)

    Sarkar, Binoy; Patra, Ashok K; Purakayastha, T J; Megharaj, Mallavarapu

    2009-09-01

    There is concern that transgenic Bt-crops carry genes that could have undesirable effects on natural and agro-ecosystem functions. We investigated the effect of Bt-cotton (expressing the Cry 1Ac protein) on several microbial and biochemical indicators in a sandy loam soil. Bt-cotton (MRC-6301Bt) and its non-transgenic near-isoline (MRC-6301) were grown in a net-house on a sandy clay loam soil. Soil and root samples were collected 60, 90, and 120 days after sowing. Soil from a control (no-crop) treatment was also included. Samples were analysed for microbial biomass C, N and P (MBC, MBN, MBP), total organic carbon (TOC), and several soil enzyme activities. The microbial quotient (MQ) was calculated as the ratio of MBC-to-TOC. The average of the three sampling events revealed a significant increase in MBC, MBN, MBP and MQ in the soil under Bt-cotton over the non-Bt isoline. The TOC was similar in Bt and non-Bt systems. Potential N mineralization, nitrification, nitrate reductase, and acid and alkaline phosphatase activities were all higher in the soil under Bt-cotton. Root dry weights were not different (P > 0.05), but root volume of Bt-cotton was higher on 90 and 120 days than that of non-Bt cotton. The time of sampling strongly affected the above parameters, with most being highest on 90 days after sowing. We concluded from the data that there were some positive or no negative effects of Bt-cotton on the studied indicators, and therefore cultivation of Bt-cotton appears to be no risk to soil ecosystem functions.

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

    Science.gov (United States)

    Luo, Jun-Yu; Zhang, Shuai; Peng, Jun; Zhu, Xiang-Zhen; Lv, Li-Min; Wang, Chun-Yi; Li, Chun-Hua; Zhou, Zhi-Guo; Cui, Jin-Jie

    2017-01-01

    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. PMID:28099508

  5. 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.

  6. BACILLUS THURINGIENSIS (BT) TOXIN RELEASED FROM ROOT EXUDATES AND BIOMASS OF BT CORN HAS NO APPARENT EFFECT ON EARTHWORMS, NEMATODES, PROTOZOA, BACTERIA, AND FUNGI IN SOIL. (R826107)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  7. Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

    Energy Technology Data Exchange (ETDEWEB)

    Himanen, Sari J. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)], E-mail: sari.himanen@uku.fi; Nerg, Anne-Marja [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); Nissinen, Anne [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland); MTT Agrifood Research Finland, Plant Protection, FIN-31600 Jokioinen (Finland); Stewart, C. Neal [University of Tennessee, Department of Plant Sciences, Knoxville, TN 37996-4561 (United States); Poppy, Guy M. [University of Southampton, School of Biological Sciences, Southampton SO16 7PX (United Kingdom); Holopainen, Jarmo K. [University of Kuopio, Department of Environmental Science, P.O. Box 1627, FIN-70211 Kuopio (Finland)

    2009-01-15

    Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. - Elevated atmospheric ozone can induce fluctuations in insecticidal protein concentrations in transgenic plants.

  8. Elevated atmospheric ozone increases concentration of insecticidal Bacillus thuringiensis (Bt) Cry1Ac protein in Bt Brassica napus and reduces feeding of a Bt target herbivore on the non-transgenic parent

    International Nuclear Information System (INIS)

    Himanen, Sari J.; Nerg, Anne-Marja; Nissinen, Anne; Stewart, C. Neal; Poppy, Guy M.; Holopainen, Jarmo K.

    2009-01-01

    Sustained cultivation of Bacillus thuringiensis (Bt) transgenic crops requires stable transgene expression under variable abiotic conditions. We studied the interactions of Bt toxin production and chronic ozone exposure in Bt cry1Ac-transgenic oilseed rape and found that the insect resistance trait is robust under ozone elevations. Bt Cry1Ac concentrations were higher in the leaves of Bt oilseed rape grown under elevated ozone compared to control treatment, measured either per leaf fresh weight or per total soluble protein of leaves. The mean relative growth rate of a Bt target herbivore, Plutella xylostella L. larvae was negative on Bt plants in all ozone treatments. On the non-transgenic plants, larval feeding damage was reduced under elevated ozone. Our results indicate the need for monitoring fluctuations in Bt toxin concentrations to reveal the potential of ozone exposure for altering dosing of Bt proteins to target and non-target herbivores in field environments experiencing increasing ozone pollution. - Elevated atmospheric ozone can induce fluctuations in insecticidal protein concentrations in transgenic plants

  9. Effects of Bt-maize material on the life cycle of the land snail Cantareus aspersus

    DEFF Research Database (Denmark)

    Kramarz, Paulina; de Vaufleury, Annette; Gimbert, Frédéric

    2009-01-01

    Insect resistant Bt-maize (MON 810) expresses active Cry1Ab endotoxin derived from Bacillus thuringiensis (Bt). Snails constitute non-target soil species potentially exposed to Bt-toxin through consumption of plant material and soil in fields where transgenic plants have been grown. We studied th...

  10. Evaluation for the retention of reproductive structures by Bt and non ...

    African Journals Online (AJOL)

    MRC 6301 also behaved like RCH group hybrids. Bt hybrids of all the three establishments had more reproductive structure retentivity than their non-Bt hybrids counterparts in early, closer inter row and wider intra row sowing except for Bt hybrid RCH134 which had the highest bearing in the late sowing with wider inter row ...

  11. Test Takers' Attitudes about the TOEFL iBT[TM]. TOEFL iBT Research Report. RR-10-2

    Science.gov (United States)

    Stricker, Lawrence J.; Attali, Yigal

    2010-01-01

    The principal aims of this study, a conceptual replication of an earlier investigation of the TOEFL[R] computer-based test, or TOEFL CBT, in Buenos Aires, Cairo, and Frankfurt, were to assess test takers' reported acceptance of the TOEFL Internet-based test, or TOEFL iBT[TM], and its associations with possible determinants of this acceptance and…

  12. Product evaluation : Dow Corning 888

    Science.gov (United States)

    1986-07-10

    This report contains a product evaluation of Dow Corning 888 joint sealant. Dow Corning 888 is a one-part silicone material that cures to a low modulus silicone rubber upon exposure to atmospheric moisture. Its uses include transverse and longitudina...

  13. FUM gene expression profile and fumonisin production by Fusarium verticillioides inoculated in Bt and non-Bt maize

    Directory of Open Access Journals (Sweden)

    Liliana Oliveira Rocha

    2016-01-01

    Full Text Available This study aimed to determine the levels of fumonisins produced by F. verticillioides and FUM gene expression on Bt (Bacillus thuringiensis and non-Bt maize, post harvest, during different periods of incubation. Transgenic hybrids 30F35 YG, 2B710 Hx and their isogenic (30F35 and 2B710 were collected from the field and a subset of 30 samples selected for the experiments. Maize samples were sterilized by gamma radiation at a dose of 20 kGy. Samples were then inoculated with Fusarium verticillioides and analysed under controlled conditions of temperature and relative humidity for fumonisin B1 and B2 (FB¬1 and FB2 production and FUM1, FUM3, FUM6, FUM7, FUM8, FUM13, FUM14, FUM15 and FUM19 expression. 2B710 Hx and 30F35 YG kernel samples were virtually intact when compared to the non-Bt hybrids that came from the field. Statistical analysis showed that FB¬1 production was significantly lower in 30F35 YG and 2B710 Hx than in the 30F35 and 2B710 hybrids (P 0.05. The kernel injuries observed in the non-Bt samples have possibly facilitated F. verticillioides penetration and promoted FB1 production under controlled conditions. FUM genes were expressed by F. verticillioides in all of the samples. However, there was indication of lower expression of a few FUM genes in the Bt hybrids; and a weak association between FB1 production and the relative expression of some of the FUM genes were observed in the 30F35 YG hybrid.

  14. Asymmetric Total Synthesis of Four Stereoisomers of the Sex Pheromone of the Western Corn Rootworm

    Directory of Open Access Journals (Sweden)

    Zhi-Feng Sun

    2018-03-01

    Full Text Available A convergent synthesis of four stereoisomers of the sex pheromone of the western corn rootworm (8-methyldecan-2-yl propionate, 1 from commercially available chiral starting materials is reported. The key step was Julia–Kocienski olefination between chiral BT-sulfone and chiral aldehyde. This synthetic route provided the four stereoisomers of 1 in 24–29% total yield via a six-step sequence. The simple scale-up strategy provides a new way to achieve the asymmetric synthesis of the sex pheromone.

  15. Calculation and Analysis of B/T (Burning and/or Transmutation Rate of Minor Actinides and Plutonium Performed by Fast B/T Reactor

    Directory of Open Access Journals (Sweden)

    Marsodi

    2006-01-01

    Full Text Available Calculation and analysis of B/T (Burning and/or Transmutation rate of MA (minor actinides and Pu (Plutonium has been performed in fast B/T reactor. The study was based on the assumption that the spectrum shift of neutron flux to higher side of neutron energy had a potential significance for designing the fast B/T reactor and a remarkable effect for increasing the B/T rate of MA and/or Pu. The spectrum shifts of neutron have been performed by change MOX to metallic fuel. Blending fraction of MA and or Pu in B/T fuel and the volume ratio of fuel to coolant in the reactor core were also considered. Here, the performance of fast B/T reactor was evaluated theoretically based on the calculation results of the neutronics and burn-up analysis. In this study, the B/T rate of MA and/or Pu increased by increasing the blending fraction of MA and or Pu and by changing the F/C ratio. According to the results, the total B/T rate, i.e. [B/T rate]MA + [B/T rate]Pu, could be kept nearly constant under the critical condition, if the sum of the MA and Pu inventory in the core is nearly constant. The effect of loading structure was examined for inner or outer loading of concentric geometry and for homogeneous loading. Homogeneous loading of B/T fuel was the good structure for obtaining the higher B/T rate, rather than inner or outer loading

  16. Impact of Bt-cotton on soil microbiological and biochemical attributes

    Directory of Open Access Journals (Sweden)

    Sanaullah Yasin

    2016-10-01

    Full Text Available Transgenic Bt-cotton produces Bt-toxins (Cry proteins which may accumulate and persist in soil due to their binding ability on soil components. In the present study, the potential impacts of Bt- and non-Bt genotypes of cotton on soil microbial activity, substrate use efficiency, viable microbial population counts, and nutrient dynamics were studied. Two transgenic Bt-cotton genotypes (CIM-602 CIM-599 expressing cry1 Ac gene and two non-Bt cotton genotypes (CIM-573 and CIM-591 were used to evaluate their impact on biological and chemical properties of soil across the four locations in Punjab. Field trials were conducted at four locations (Central Cotton Research Institute-Multan, Naseer Pur, Kot Lal Shah, and Cotton Research Station-Bahawalpur of different agro-ecological zones of Punjab. Rhizosphere soil samples were collected by following standard procedure from these selected locations. Results reveled that Bt-cotton had no adverse effect on microbial population (viable counts and enzymatic activity of rhizosphere soil. Bacterial population was more in Bt-cotton rhizosphere than that of non-Bt cotton rhizosphere at all locations. Phosphatase, dehydrogenase, and oxidative metabolism of rhizosphere soil were more in Bt-cotton genotypes compared with non-Bt cotton genotypes. Cation exchange capacity, total nitrogen, extractable phosphorous, extractable potassium, active carbon, Fe and Zn contents were higher in rhizosphere of Bt-cotton genotypes compared with non-Bt cotton genotypes. It can be concluded from present study that the cultivation of Bt-cotton expressing cry1 Ac had apparently no negative effect on metabolic, microbiological activities, and nutrient dynamics of soils. Further work is needed to investigate the potential impacts of Bt-cotton on ecology of soil-dwelling insects and invertebrates before its recommendation for extensive cultivation.

  17. Effects of feeding transgenic corn with mCry1Ac or maroACC gene to laying hens for 12 weeks on growth, egg quality and organ health.

    Science.gov (United States)

    Zhong, R Q; Chen, L; Gao, L X; Zhang, L L; Yao, B; Yang, X G; Zhang, H F

    2016-08-01

    The objective of the present study was to investigate the effect of feeding two transgenic corn lines containing the mCry1Ac gene from Bacillus thuringiensis strain (BT-799) and the maroACC gene from Agrobacterium tumefaciens strain (CC-2), respectively, on growth, egg quality and organ health indicators. Expression of the mCry1Ac gene confers resistance to Pyrausta nubilalis and the maroACC gene confers tolerance to herbicides. Healthy hens (n=96 placed in cages; 3 hens/cage) were randomly assigned to one of four corn-soybean meal dietary treatments (8 cages/treatment) formulated with the following corn: non-transgenic near-isoline control corn (control), BT-799 corn, CC-2 corn and commercially available non-transgenic reference corn (reference). The experiment was divided into three 4-week phases (week 1 to 4, week 5 to 8 and week 9 to 12), during which hens were fed mash diets. Performance (BW, feed intake and egg production) and egg quality were determined. Following slaughter at the end of 12 weeks of feeding (n=8/treatment), carcass yield and organ weights (heart, liver, spleen, lung, kidneys, stomach and ovary) were recorded; organs and intestines were sampled for histological analysis. Analysis of serum biochemistry parameters to assess the liver and kidney function were performed. No differences in BW, egg production and production efficiency were observed between hens consuming the control diet and hens consuming the BT-799 or CC-2 diet. Haugh unit measures and egg component weights were similar between the control and test groups. Carcass yield was not affected by the diet treatment. Similar organosomatic indices and serum parameters did not indicate the characteristics of organ dysfunction. All observed values of the BT-799 and CC-2 groups were within the calculated tolerance intervals. This research indicates that the performance, egg quality, organ health and carcass yield of laying hens fed diets containing the BT-799 or CC-2 corn line were similar

  18. Changes in bacillus thuringiensis tolerance levels due to hybridization of Bt-tolerant and susceptible silkworm populations

    International Nuclear Information System (INIS)

    Begumad, H.A.; Hassana, E.; Dingleb, J.; Alshehic, A.A.

    2012-01-01

    Males and females of a Bt-tolerant mulberry silkworm (Bombyx mori L.) population were crossed with females and males of a Bt-susceptible population, to produce Bt-tolerant silkworm hybrids, and to determine the expression of the Bt-tolerance pattern in the F 1 hybrids. It was observed that when a Bt-tolerant (42% larval mortality) female (BtT ) silkworm was crossed with a Bt-susceptible (85% larval mortality) male (BtS ), the resultant F 1 offspring showed lower levels of Bt-tolerance (87% larval mortality). On the other hand, when a Bt-tolerant male (BtT ) was crossed with a Bt-susceptible female (BtS ), the F 1 hybrid showed higher levels of Bt-tolerance (35% larval mortality) characteristic. The probit statistics showed that both hybrids expressed Bt-tolerance or susceptible levels similar to their male parents. These different patterns of Bt-tolerance in F 1 hybrids might be due to the transferring of a Bt-tolerant gene, from the parents to offspring, through the homozygotic male (ZZ) silkworm. (author)

  19. Bt crop effects on functional guilds of non-target arthropods: a meta-analysis.

    Science.gov (United States)

    Wolfenbarger, L LaReesa; Naranjo, Steven E; Lundgren, Jonathan G; Bitzer, Royce J; Watrud, Lidia S

    2008-05-07

    Uncertainty persists over the environmental effects of genetically-engineered crops that produce the insecticidal Cry proteins of Bacillus thuringiensis (Bt). We performed meta-analyses on a modified public database to synthesize current knowledge about the effects of Bt cotton, maize and potato on the abundance and interactions of arthropod non-target functional guilds. We compared the abundance of predators, parasitoids, omnivores, detritivores and herbivores under scenarios in which neither, only the non-Bt crops, or both Bt and non-Bt crops received insecticide treatments. Predators were less abundant in Bt cotton compared to unsprayed non-Bt controls. As expected, fewer specialist parasitoids of the target pest occurred in Bt maize fields compared to unsprayed non-Bt controls, but no significant reduction was detected for other parasitoids. Numbers of predators and herbivores were higher in Bt crops compared to sprayed non-Bt controls, and type of insecticide influenced the magnitude of the difference. Omnivores and detritivores were more abundant in insecticide-treated controls and for the latter guild this was associated with reductions of their predators in sprayed non-Bt maize. No differences in abundance were found when both Bt and non-Bt crops were sprayed. Predator-to-prey ratios were unchanged by either Bt crops or the use of insecticides; ratios were higher in Bt maize relative to the sprayed non-Bt control. Overall, we find no uniform effects of Bt cotton, maize and potato on the functional guilds of non-target arthropods. Use of and type of insecticides influenced the magnitude and direction of effects; insecticde effects were much larger than those of Bt crops. These meta-analyses underscore the importance of using controls not only to isolate the effects of a Bt crop per se but also to reflect the replacement of existing agricultural practices. Results will provide researchers with information to design more robust experiments and will inform the

  20. Bt crop effects on functional guilds of non-target arthropods: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    L LaReesa Wolfenbarger

    Full Text Available BACKGROUND: Uncertainty persists over the environmental effects of genetically-engineered crops that produce the insecticidal Cry proteins of Bacillus thuringiensis (Bt. We performed meta-analyses on a modified public database to synthesize current knowledge about the effects of Bt cotton, maize and potato on the abundance and interactions of arthropod non-target functional guilds. METHODOLOGY/PRINCIPAL FINDINGS: We compared the abundance of predators, parasitoids, omnivores, detritivores and herbivores under scenarios in which neither, only the non-Bt crops, or both Bt and non-Bt crops received insecticide treatments. Predators were less abundant in Bt cotton compared to unsprayed non-Bt controls. As expected, fewer specialist parasitoids of the target pest occurred in Bt maize fields compared to unsprayed non-Bt controls, but no significant reduction was detected for other parasitoids. Numbers of predators and herbivores were higher in Bt crops compared to sprayed non-Bt controls, and type of insecticide influenced the magnitude of the difference. Omnivores and detritivores were more abundant in insecticide-treated controls and for the latter guild this was associated with reductions of their predators in sprayed non-Bt maize. No differences in abundance were found when both Bt and non-Bt crops were sprayed. Predator-to-prey ratios were unchanged by either Bt crops or the use of insecticides; ratios were higher in Bt maize relative to the sprayed non-Bt control. CONCLUSIONS/SIGNIFICANCE: Overall, we find no uniform effects of Bt cotton, maize and potato on the functional guilds of non-target arthropods. Use of and type of insecticides influenced the magnitude and direction of effects; insecticde effects were much larger than those of Bt crops. These meta-analyses underscore the importance of using controls not only to isolate the effects of a Bt crop per se but also to reflect the replacement of existing agricultural practices. Results will

  1. Discourse Characteristics of Writing and Speaking Task Types on the "TOEFL iBT"® Test: A Lexico-Grammatical Analysis. "TOEFL iBT"® Research Report. TOEFL iBT-19. Research Report. RR-13-04

    Science.gov (United States)

    Biber, Douglas; Gray, Bethany

    2013-01-01

    One of the major innovations of the "TOEFL iBT"® test is the incorporation of integrated tasks complementing the independent tasks to which examinees respond. In addition, examinees must produce discourse in both modes (speech and writing). The validity argument for the TOEFL iBT includes the claim that examinees vary their discourse in…

  2. Investigating the Value of Section Scores for the "TOEFL iBT"® Test. "TOEFL iBT"® Research Report. TOEFL iBT-21. ETS Research Report RR-13-35

    Science.gov (United States)

    Sawaki, Yasuyo; Sinharay, Sandip

    2013-01-01

    This study investigates the value of reporting the reading, listening, speaking, and writing section scores for the "TOEFL iBT"® test, focusing on 4 related aspects of the psychometric quality of the TOEFL iBT section scores: reliability of the section scores, dimensionality of the test, presence of distinct score profiles, and the…

  3. Corn in consortium with forages

    Directory of Open Access Journals (Sweden)

    Cássia Maria de Paula Garcia

    2013-12-01

    Full Text Available The basic premises for sustainable agricultural development with focus on rural producers are reducing the costs of production and aggregation of values through the use crop-livestock system (CLS throughout the year. The CLS is based on the consortium of grain crops, especially corn with tropical forages, mainly of the genus Panicum and Urochloa. The study aimed to evaluate the grain yield of irrigated corn crop intercropped with forage of the genus Panicum and Urochloa. The experiment was conducted at the Fazenda de Ensino, Pesquisa e Extensão – FEPE  of the Faculdade de Engenharia - UNESP, Ilha Solteira in an Oxisol in savannah conditions and in the autumn winter of 2009. The experimental area was irrigated by a center pivot and had a history of no-tillage system for 8 years. The corn hybrid used was simple DKB 390 YG at distances of 0.90 m. The seeds of grasses were sown in 0.34 m spacing in the amount of 5 kg ha-1, they were mixed with fertilizer minutes before sowing  and placed in a compartment fertilizer seeder and fertilizers were mechanically deposited in the soil at a depth of 0.03 m. The experimental design used was a randomized block with four replications and five treatments: Panicum maximum cv. Tanzania sown during the nitrogen fertilization (CTD of the corn; Panicum maximum cv. Mombaça sown during the nitrogen fertilization (CMD of the corn; Urochloa brizantha cv. Xaraés sown during the occasion of nitrogen fertilization (CBD of the corn; Urochloa ruziziensis cv. Comumsown during the nitrogen fertilization (CRD of the corn and single corn (control. The production components of corn: plant population per hectare (PlPo, number of ears per hectare (NE ha-1, number of rows per ear (NRE, number of kernels per row on the cob (NKR, number of grain in the ear (NGE and mass of 100 grains (M100G were not influenced by consortium with forage. Comparing grain yield (GY single corn and maize intercropped with forage of the genus Panicum

  4. Decrease in catalase activity of Folsomia candida fed a Bt rice diet

    International Nuclear Information System (INIS)

    Yuan Yiyang; Ke Xin; Chen Fajun; Krogh, Paul Henning; Ge Feng

    2011-01-01

    Here we report the effects of three Bt-rice varieties and their non-Bt conventional isolines on biological traits including survival, reproduction, and the activities of three antioxidant enzymes superoxide dismutase, catalase and peroxidase, in the Collembolan, Folsomia candida. The reproduction was significantly lower when fed Kemingdao and Huahui1 than those feeding on their non-GM near-isogenic varieties Xiushui and Minghui63 respectively, this can be explained by the differences of plant compositions depended on variety of rice. The catalase activity of F. candida was significantly lower when fed the Bt-rice variety Kemingdao compared to the near-isogenic non-Bt-rice variety Xiushui. This suggests that some Bt-rice varieties may impose environmental stress to collembolans. We emphasize that changes in activity of antioxidant enzymes of non-target organisms are important in understanding the ecological consequences for organisms inhabiting transgenic Bt-rice plantations. - Highlights: → We examine the effects of Bt-rice on Folsomia candida with laboratory test. → The reproduction of F. candida was decreased by two Bt-rice varieties. → Decreased reproduction caused by the differences of varieties or C/N ratio of rice. → The catalase activity was decreased by Bt-rice Kemingdao. → Some Bt-rice may impose environmental stress on NTOs. - The catalase of the collembolan (Folsomia candida) was decreased when fed Bt-rice, Kemingdao.

  5. Corn Culture: A Story of Intelligent Design

    Science.gov (United States)

    Todd, Jude

    2008-01-01

    Scientists are not sure of how corn was created. There were two competing genetic theories about how corn came to be. One theory maintains that corn had been teased out of a wheatlike grass called teosinte (genus Zea), and the other contends that one now-extinct ancestor of corn had crossed with another grass, "Tripsacum," several millennia ago.…

  6. The food and environmental safety of Bt crops.

    Science.gov (United States)

    Koch, Michael S; Ward, Jason M; Levine, Steven L; Baum, James A; Vicini, John L; Hammond, Bruce G

    2015-01-01

    Bacillus thuringiensis (Bt) microbial pesticides have a 50-year history of safety in agriculture. Cry proteins are among the active insecticidal ingredients in these pesticides, and genes coding for Cry proteins have been introduced into agricultural crops using modern biotechnology. The Cry gene sequences are often modified to enable effective expression in planta and several Cry proteins have been modified to increase biological activity against the target pest(s). Additionally, the domains of different but structurally conserved Cry proteins can be combined to produce chimeric proteins with enhanced insecticidal properties. Environmental studies are performed and include invertebrates, mammals, and avian species. Mammalian studies used to support the food and feed safety assessment are also used to support the wild mammal assessment. In addition to the NTO assessment, the environmental assessment includes a comparative assessment between the Bt crop and the appropriate conventional control that is genetically similar but lacks the introduced trait to address unintended effects. Specific phenotypic, agronomic, and ecological characteristics are measured in the Bt crop and the conventional control to evaluate whether the introduction of the insect resistance has resulted in any changes that might cause ecological harm in terms of altered weed characteristics, susceptibility to pests, or adverse environmental impact. Additionally, environmental interaction data are collected in field experiments for Bt crop to evaluate potential adverse effects. Further to the agronomic and phenotypic evaluation, potential movement of transgenes from a genetically modified crop plants into wild relatives is assessed for a new pest resistance gene in a new crop. This review summarizes the evidence for safety of crops containing Cry proteins for humans, livestock, and other non-target organisms.

  7. The food and environmental safety of Bt crops

    Science.gov (United States)

    Koch, Michael S.; Ward, Jason M.; Levine, Steven L.; Baum, James A.; Vicini, John L.; Hammond, Bruce G.

    2015-01-01

    Bacillus thuringiensis (Bt) microbial pesticides have a 50-year history of safety in agriculture. Cry proteins are among the active insecticidal ingredients in these pesticides, and genes coding for Cry proteins have been introduced into agricultural crops using modern biotechnology. The Cry gene sequences are often modified to enable effective expression in planta and several Cry proteins have been modified to increase biological activity against the target pest(s). Additionally, the domains of different but structurally conserved Cry proteins can be combined to produce chimeric proteins with enhanced insecticidal properties. Environmental studies are performed and include invertebrates, mammals, and avian species. Mammalian studies used to support the food and feed safety assessment are also used to support the wild mammal assessment. In addition to the NTO assessment, the environmental assessment includes a comparative assessment between the Bt crop and the appropriate conventional control that is genetically similar but lacks the introduced trait to address unintended effects. Specific phenotypic, agronomic, and ecological characteristics are measured in the Bt crop and the conventional control to evaluate whether the introduction of the insect resistance has resulted in any changes that might cause ecological harm in terms of altered weed characteristics, susceptibility to pests, or adverse environmental impact. Additionally, environmental interaction data are collected in field experiments for Bt crop to evaluate potential adverse effects. Further to the agronomic and phenotypic evaluation, potential movement of transgenes from a genetically modified crop plants into wild relatives is assessed for a new pest resistance gene in a new crop. This review summarizes the evidence for safety of crops containing Cry proteins for humans, livestock, and other non-target organisms. PMID:25972882

  8. The Food and Environmental Safety of Bt Crops

    Directory of Open Access Journals (Sweden)

    Michael Stephen Koch

    2015-04-01

    Full Text Available Bt (Bacillus thuringiensis microbial pesticides have a 50-year history of safe use in agriculture. Cry proteins are among the active insecticidal ingredients in these pesticides, and genes coding for Cry proteins have been introduced into agricultural crops using modern biotechnology. The Cry gene sequences are often modified to enable effective expression in planta and several Cry proteins have been modified to increase biological activity against the target pest(s. Additionally, the domains of different but structurally conserved Cry proteins can be combined to produce chimeric proteins with enhanced insecticidal properties. Environmental studies are performed and include invertebrates, mammals and avian species. Mammalian studies used to support the food and feed safety assessment are also used to support the wild mammal assessment. In addition to the NTO assessment, the environmental assessment includes a comparative assessment between the Bt crop and the appropriate conventional control that is genetically similar but lacks the introduced trait to address unintended effects. Specific phenotypic, agronomic, and ecological characteristics are measured in the Bt crop and the conventional control to evaluate whether the introduction of the insect resistance has resulted in any changes that might cause ecological harm in terms of altered weed characteristics, susceptibility to pests, or adverse environmental impact. Additionally, environmental interaction data are collected in field experiments for Bt crop to evaluate potential adverse effects. Further to the agronomic and phenotypic evaluation, potential movement of transgenes from a genetically modified crop plants into wild relatives is assessed for a new pest resistance gene in a new crop. This review summarizes the evidence for safety of crops containing Cry proteins for humans, livestock, and other non-target organisms.

  9. Effects of transgenic Bt cotton on soil fertility and biology under field conditions in subtropical inceptisol.

    Science.gov (United States)

    Singh, Raman Jeet; Ahlawat, I P S; Singh, Surender

    2013-01-01

    Although there is large-scale adoption of Bt cotton by the farmers because of immediate financial gain, there is concern that Bt crops release Bt toxins into the soil environment which reduces soil chemical and biological activities. However, the majorities of such studies were mainly performed under pot experiments, relatively little research has examined the direct and indirect effects of associated cover crop of peanut with fertilization by combined application of organic and inorganic sources of nitrogen under field conditions. We compared soil chemical and biological parameters of Bt cotton with pure crop of peanut to arrive on a valid conclusion. Significantly higher dehydrogenase enzyme activity and KMnO(4)-N content of soil were observed in Bt cotton with cover crop of peanut over pure Bt cotton followed by pure peanut at all the crop growth stages. However, higher microbial population was maintained by pure peanut over intercropped Bt cotton, but these differences were related to the presence of high amount of KMnO(4)-N content of soil. By growing cover crop of peanut between Bt cotton rows, bacteria, fungi, and actinomycetes population increased by 60%, 14%, and 10%, respectively, over Bt cotton alone. Bt cotton fertilized by combined application of urea and farm yard manure (FYM) maintained higher dehydrogenase enzyme activity, KMnO(4)-N content of soil and microbial population over urea alone. Significant positive correlations were observed for dry matter accumulation, dehydrogenase enzyme activity, KMnO(4)-N content, and microbial population of soil of Bt cotton, which indicates no harmful effects of Bt cotton on soil biological parameters and associated cover crop. Our results suggest that inclusion of cover crop of peanut and FYM in Bt cotton enhanced soil chemical and biological parameters which can mask any negative effect of the Bt toxin on microbial activity and thus on enzymatic activities.

  10. Effect of Bt cotton on nutrient dynamics under varied soil type

    Directory of Open Access Journals (Sweden)

    Kasturikasen Beura

    2011-12-01

    Full Text Available Since transgenic cotton was first grown commercially in India in 1996, the areas cultivated have increased rapidly around the world. Bt cotton is produced by inserting a synthetic version of a gene from the naturally occurring soil bacterium Bacillus thuringiensis into cotton. Bt cotton may affect nutrient dynamics in many ways during its life-span with regard to the temporal-spatial relevance of Bt proteins. Given this, we aimed to evaluate nutrient availability under both Bt and non-Bt systems and varied soil type. The study was conducted during the 2010 wet season (July to December in a net-house at the Institute of Agricultural Sciences of Banaras Hindu University. It was carried out on three different soil orders i.e. entisol, inceptisol and alfisol. Bt-cotton (cvNCS-138 and its non-transgenic isoline (cvNCS-138 were grown until maturity. A no crop pot was maintained with three replications for all the three soil orders. Study design was a factorial experiment under a completely randomized block design with three replications. The study concludes that available N was reduced by 12-13% under Bt-cotton compared to non-Bt isoline and no crop treatment whereas it showed a significant increase in available P in the soil under Bt-cotton (7.8% increase compared to non-Bt isoline and no crop treatment. Furthermore, it has been observed that available K value varied from 82.88 kg ha-1 to 76.88 kg ha-1 in the soil under Bt-cotton and from 90.33 kg hato-1 83.55 kg ha-1 in the non-Bt crops and a significant increase in the Avalaible Zn in the soil under Bt-cotton compared to non-Bt isoline and no crop treatment.

  11. Ethanol extraction of phytosterols from corn fiber

    Science.gov (United States)

    Abbas, Charles; Beery, Kyle E.; Binder, Thomas P.; Rammelsberg, Anne M.

    2010-11-16

    The present invention provides a process for extracting sterols from a high solids, thermochemically hydrolyzed corn fiber using ethanol as the extractant. The process includes obtaining a corn fiber slurry having a moisture content from about 20 weight percent to about 50 weight percent solids (high solids content), thermochemically processing the corn fiber slurry having high solids content of 20 to 50% to produce a hydrolyzed corn fiber slurry, dewatering the hydrolyzed corn fiber slurry to achieve a residual corn fiber having a moisture content from about 30 to 80 weight percent solids, washing the residual corn fiber, dewatering the washed, hydrolyzed corn fiber slurry to achieve a residual corn fiber having a moisture content from about 30 to 80 weight percent solids, and extracting the residual corn fiber with ethanol and separating at least one sterol.

  12. Corning lightweight core fabrication technologies

    Science.gov (United States)

    VanBrocklin, Randy R.; Edwards, Mary J.; Hobbs, Thomas W.

    2003-12-01

    Fabrication of lightweight mirrors from low expansion glasses can be achieved using various core and faceplate lightweighting techniques. Lightweighting can be achieved using abrasive waterjet cutting, CNC milling and a new approach that Corning is developing to produce lightweight cores based on Corning's patented ceramic extrusion process. The selection of which lightweighting technology to use is dependent on customer design considerations of the lightweight mirror. These lightweighting techniques are reviewed and discussed, along with advantages and disadvantages of each technique. Corning will also introduce and discuss their new core lightweighting process.

  13. 21 CFR 184.1321 - Corn gluten.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Corn gluten. 184.1321 Section 184.1321 Food and... Substances Affirmed as GRAS § 184.1321 Corn gluten. (a) Corn gluten (CAS Reg. No. 66071-96-3), also known as corn gluten meal, is the principal protein component of corn endosperm. It consists mainly of zein and...

  14. Integrated bioethanol production from mixtures of corn and corn stover.

    Science.gov (United States)

    Chen, Sitong; Xu, Zhaoxian; Li, Xiujuan; Yu, Jianming; Cai, Mufeng; Jin, Mingjie

    2018-02-27

    Conversion of lignocellulosic biomass, such as corn stover (CS), to ethanol has encountered issues of inhibition from degradation products, low ethanol titer and low ethanol productivity. This work integrated CS into corn ethanol process for effective conversion. CS was pretreated using either dilute alkali or dilute acid pretreatment. The pretreated CS was enzymatically hydrolyzed and then mixed with liquefied corn for ethanol fermentation. Fermentation strains, substrate mixing ratios and fed-batch strategy were investigated. The mixture of alkali pretreated CS and corn at solids loadings of 10% and 20%, respectively, resulted in 92.30 g/L ethanol. Ethanol titer was further improved to 96.43 g/L with a fed-batch strategy. The mixture of dilute acid pretreated CS and corn achieved a better performance, leading to 104.9 g/L ethanol with 80.47% ethanol yield and a productivity as high as 2.19 g/L/h. This work demonstrated effective conversion of CS and corn together to ethanol. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Effect of genetically modified corn on the jejunal mucosa of adult male albino rat.

    Science.gov (United States)

    Ibrahim, Marwa A A; Okasha, Ebtsam F

    2016-11-01

    Genetically modified (GM) plants expressing insecticidal traits offer a new strategy for crop protection. GM-corn contains Bacillus thuringiensis (Bt) genes producing delta endotoxins in the whole plant. Diet can influence the characteristics of the gastrointestinal tract altering its function and structure. The aim of this study was to evaluate the effect of GM-corn on the histological structure of jejunal mucosa of adult male albino rat using different histological, immunohistochemical and morphometrical methods. Twenty adult male albino rats were divided into two equal groups; control and GM-corn fed group administered with 30% GM-corn for 90days. Specimens from the jejunum were processed for light and electron microscopy. Immunohistochemical study was carried out using antibody against proliferating cell nuclear antigen (PCNA). Different morphometrical parameters were assessed. Specimens from GM-corn fed group showed different forms of structural changes. Focal destruction and loss of the villi leaving denuded mucosal surface alternating with stratified areas were observed, while some crypts appeared totally disrupted. Congested blood capillaries and focal infiltration with mononuclear cells were detected. Significant upregulation of PCNA expression, increase in number of goblet cells and a significant increase in both villous height and crypt depth were detected. Marked ultrastructural changes of some enterocytes with focal loss of the microvillous border were observed. Some enterocytes had vacuolated cytoplasm, swollen mitochondria with disrupted cristae and dilated rough endoplasmic reticulum (rER). Some cells had dark irregular nuclei with abnormally clumped chromatin. It could be concluded that consumption of GM-corn profoundly alters the jejunal histological structure. Copyright © 2016 Elsevier GmbH. All rights reserved.

  16. Development of Corn Stover Biofuel: Impacts on Corn and Soybean Markets and Land Rotation

    OpenAIRE

    Taheripour, Farzad; Tyner, Wallace E.; Fiegel, Julie

    2013-01-01

    This paper first develops a partial equilibrium (PE) model to examine impacts of converting corn stover to biofuel on markets for corn and soybeans at the national market level. The PE model links gasoline, corn ethanol, dried distiller grains, corn, soybeans, and soybean meal markets in the presence and absence of a viable market for corn stover. The model also includes a technology which converts corn stover to bio-gasoline (a drop-in biofuel). The model evaluates profitability of the ethan...

  17. Diminishing returns from increased percent Bt cotton: the case of pink bollworm.

    Directory of Open Access Journals (Sweden)

    Yunxin Huang

    Full Text Available Regional suppression of pests by transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt has been reported in several cropping systems, but little is known about the functional relationship between the ultimate pest population density and the pervasiveness of Bt crops. Here we address this issue by analyzing 16 years of field data on pink bollworm (Pectinophora gossypiella population density and percentage of Bt cotton in 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 find that as the percent Bt cotton increased over the years, the cross-year growth rate of pink bollworm from the last generation of one year to the first generation of the next year decreased. However, as the percent Bt cotton increased, the within-year growth rate of pink bollworm from the first to last generation of the same year increased, with a slope approximately opposite to that of the cross-year rates. As a result, we did not find a statistically significant decline in the annual growth rate of pink bollworm as the percent Bt cotton increased over time. Consistent with the data, our modeling analyses predict that the regional average density of pink bollworm declines as the percent Bt cotton increases, but the higher the percent Bt cotton, the slower the decline in pest density. Specifically, we find that 95% Bt cotton is predicted to cause only 3% more reduction in larval density than 80% Bt cotton. The results here suggest that density dependence can act against the decline in pest density and diminish the net effects of Bt cotton on suppression of pink bollworm in the study region. The findings call for more studies of the interactions between pest density-dependence and Bt crops.

  18. Spatio-Temporal Variation in Landscape Composition May Speed Resistance Evolution of Pests to Bt Crops.

    Directory of Open Access Journals (Sweden)

    Anthony R Ives

    Full Text Available Transgenic crops that express insecticide genes from Bacillus thuringiensis (Bt are used worldwide against moth and beetle pests. Because these engineered plants can kill over 95% of susceptible larvae, they can rapidly select for resistance. Here, we use a model for a pyramid two-toxin Bt crop to explore the consequences of spatio-temporal variation in the area of Bt crop and non-Bt refuge habitat. We show that variability over time in the proportion of suitable non-Bt breeding habitat, Q, or in the total area of Bt and suitable non-Bt habitat, K, can increase the overall rate of resistance evolution by causing short-term surges of intense selection. These surges can be exacerbated when temporal variation in Q and/or K cause high larval densities in refuges that increase density-dependent mortality; this will give resistant larvae in Bt fields a relative advantage over susceptible larvae that largely depend on refuges. We address the effects of spatio-temporal variation in a management setting for two bollworm pests of cotton, Helicoverpa armigera and H. punctigera, and field data on landscape crop distributions from Australia. Even a small proportion of Bt fields available to egg-laying females when refuges are sparse may result in high exposure to Bt for just a single generation per year and cause a surge in selection. Therefore, rapid resistance evolution can occur when Bt crops are rare rather than common in the landscape. These results highlight the need to understand spatio-temporal fluctuations in the landscape composition of Bt crops and non-Bt habitats in order to design effective resistance management strategies.

  19. Characteristics of a broad lytic spectrum endolysin from phage BtCS33 of Bacillus thuringiensis.

    Science.gov (United States)

    Yuan, Yihui; Peng, Qin; Gao, Meiying

    2012-12-19

    Endolysins produced by bacteriophages lyse bacteria, and are thus considered a novel type of antimicrobial agent. Several endolysins from Bacillus phages or prophages have previously been characterized and used to target Bacillus strains that cause disease in animals and humans. B. thuringiensis phage BtCS33 is a Siphoviridae family phage and its genome has been sequenced and analyzed. In the BtCS33 genome, orf18 was found to encode an endolysin protein (PlyBt33). Bioinformatic analyses showed that endolysin PlyBt33 was composed of two functional domains, the N-terminal catalytic domain and the C-terminal cell wall binding domain. In this study, the entire endolysin PlyBt33, and both the N- and C-termini,were expressed in Escherichia coli and then purified. The lytic activities of PlyBt33 and its N-terminus were tested on bacteria. Both regions exhibited lytic activity, although PlyBt33 showed a higher lytic activity than the N-terminus. PlyBt33 exhibited activity against all Bacillus strains tested from five different species, but was not active against Gram-negative bacteria. Optimal conditions for PlyBt33 reactivity were pH 9.0 and 50 °C. PlyBt33 showed high thermostability, with 40% of initial activity remaining following 1 h of treatment at 60 °C. The C-terminus of PlyBt33 bound to B. thuringiensis strain HD-73 and Bacillus subtilis strain 168. This cell wall binding domain might be novel, as its amino acid sequence showed little similarity to previously reported endolysins. PlyBt33 showed potential as a novel antimicrobial agent at a relatively high temperature and had a broad lytic spectrum within the Bacillus genus. The C-terminus of PlyBt33 might be a novel kind of cell wall binding domain.

  20. Characteristics of a broad lytic spectrum endolysin from phage BtCS33 of Bacillus thuringiensis

    Directory of Open Access Journals (Sweden)

    Yuan Yihui

    2012-12-01

    Full Text Available Abstract Background Endolysins produced by bacteriophages lyse bacteria, and are thus considered a novel type of antimicrobial agent. Several endolysins from Bacillus phages or prophages have previously been characterized and used to target Bacillus strains that cause disease in animals and humans. B. thuringiensis phage BtCS33 is a Siphoviridae family phage and its genome has been sequenced and analyzed. In the BtCS33 genome, orf18 was found to encode an endolysin protein (PlyBt33. Results Bioinformatic analyses showed that endolysin PlyBt33 was composed of two functional domains, the N-terminal catalytic domain and the C-terminal cell wall binding domain. In this study, the entire endolysin PlyBt33, and both the N- and C-termini,were expressed in Escherichia coli and then purified. The lytic activities of PlyBt33 and its N-terminus were tested on bacteria. Both regions exhibited lytic activity, although PlyBt33 showed a higher lytic activity than the N-terminus. PlyBt33 exhibited activity against all Bacillus strains tested from five different species, but was not active against Gram-negative bacteria. Optimal conditions for PlyBt33 reactivity were pH 9.0 and 50°C. PlyBt33 showed high thermostability, with 40% of initial activity remaining following 1 h of treatment at 60°C. The C-terminus of PlyBt33 bound to B. thuringiensis strain HD-73 and Bacillus subtilis strain 168. This cell wall binding domain might be novel, as its amino acid sequence showed little similarity to previously reported endolysins. Conclusions PlyBt33 showed potential as a novel antimicrobial agent at a relatively high temperature and had a broad lytic spectrum within the Bacillus genus. The C-terminus of PlyBt33 might be a novel kind of cell wall binding domain.

  1. Diminishing returns from increased percent Bt cotton: the case of pink bollworm.

    Science.gov (United States)

    Huang, Yunxin; Wan, Peng; Zhang, Huannan; Huang, Minsong; Li, Zhaohua; Gould, Fred

    2013-01-01

    Regional suppression of pests by transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) has been reported in several cropping systems, but little is known about the functional relationship between the ultimate pest population density and the pervasiveness of Bt crops. Here we address this issue by analyzing 16 years of field data on pink bollworm (Pectinophora gossypiella) population density and percentage of Bt cotton in 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 find that as the percent Bt cotton increased over the years, the cross-year growth rate of pink bollworm from the last generation of one year to the first generation of the next year decreased. However, as the percent Bt cotton increased, the within-year growth rate of pink bollworm from the first to last generation of the same year increased, with a slope approximately opposite to that of the cross-year rates. As a result, we did not find a statistically significant decline in the annual growth rate of pink bollworm as the percent Bt cotton increased over time. Consistent with the data, our modeling analyses predict that the regional average density of pink bollworm declines as the percent Bt cotton increases, but the higher the percent Bt cotton, the slower the decline in pest density. Specifically, we find that 95% Bt cotton is predicted to cause only 3% more reduction in larval density than 80% Bt cotton. The results here suggest that density dependence can act against the decline in pest density and diminish the net effects of Bt cotton on suppression of pink bollworm in the study region. The findings call for more studies of the interactions between pest density-dependence and Bt crops.

  2. Corn in consortium with forages

    OpenAIRE

    Cássia Maria de Paula Garcia; Marcelo Andreotti; Marcelo Carvalho Minhoto Teixeira Filho; Keny Samejima Mascarenha Lopes; Ciniro Costa; Erikelly Aline Ribeiro de Santana

    2013-01-01

    The basic premises for sustainable agricultural development with focus on rural producers are reducing the costs of production and aggregation of values through the use crop-livestock system (CLS) throughout the year. The CLS is based on the consortium of grain crops, especially corn with tropical forages, mainly of the genus Panicum and Urochloa. The study aimed to evaluate the grain yield of irrigated corn crop intercropped with forage of the genus Panicum and Urochloa. The experiment was c...

  3. Effects of temperature on the feeding behavior of Alabama argillacea (Hübner (Lepidoptera: Noctuidae on Bt and non-Bt cotton plants

    Directory of Open Access Journals (Sweden)

    FRANCISCO S. RAMALHO

    2017-12-01

    Full Text Available ABSTRACT The host acceptance behavior and environmental factors as temperature affect the feeding behavior of Lepidoptera pests. Thus, they must be considered in studies about the risk potential of resistance evolution. The current study sets the differences in the feeding behavior of neonate Alabama argillacea (Hübner (Lepidoptera: Noctuidae larvae exposed to Bt and non-Bt cotton plants, under different temperatures and time gap after hatching. Two cotton cultivars were used: the Bt (DP 404 BG - bollgard and the non-transformed isoline, DP 4049. We found that the feeding behavior of neonate A. argillacea is significantly different between Bt and non-Bt cotton. Based on the number of larvae with vegetal tissue in their gut found on the plant and in the organza as well as on the amount of vegetal tissue ingested by the larvae. A. argillacea shows feeding preference for non-Bt cotton plants, in comparison to that on the Bt. However, factors such as temperature and exposure time may affect detection capacity and plant abandonment by the larvae and it results in lower ingestion of vegetal tissue. Such results are relevant to handle the resistance of Bt cotton cultivars to A. argillacea and they also enable determining how the cotton seeds mix will be a feasible handling option to hold back resistance evolution in A. argillacea populations on Bt cotton, when it is compared to other refuge strategies. The results can also be useful to determine which refuge distribution of plants is more effective for handling Bt cotton resistance to A. argillacea.

  4. Detection of genetically modified organisms in foreign-made processed foods containing corn and potato.

    Science.gov (United States)

    Monma, Kimio; Araki, Rie; Sagi, Naoki; Satoh, Masaki; Ichikawa, Hisatsugu; Satoh, Kazue; Tobe, Takashi; Kamata, Kunihiro; Hino, Akihiro; Saito, Kazuo

    2005-06-01

    Investigations of the validity of labeling regarding genetically modified (GM) products were conducted using polymerase chain reaction (PCR) methods for foreign-made processed foods made from corn and potato purchased in the Tokyo area and in the USA. Several kinds of GM crops were detected in 12 of 32 samples of processed corn samples. More than two GM events for which safety reviews have been completed in Japan were simultaneously detected in 10 samples. GM events MON810 and Bt11 were most frequently detected in the samples by qualitative PCR methods. MON810 was detected in 11 of the 12 samples, and Bt11 was detected in 6 of the 12 samples. In addition, Roundup Ready soy was detected in one of the 12 samples. On the other hand, CBH351, for which the safety assessment was withdrawn in Japan, was not detected in any of the 12 samples. A trial quantitative analysis was performed on six of the GM maize qualitatively positive samples. The estimated amounts of GM maize in these samples ranged from 0.2 to 2.8%, except for one sample, which contained 24.1%. For this sample, the total amount found by event-specific quantitative analysis was 23.8%. Additionally, Roundup Ready soy was detected in one sample of 21 potato-processed foods, although GM potatoes were not detected in any sample.

  5. The western corn rootworm, a new threat to European agriculture: opportunities for biotechnology?

    Science.gov (United States)

    Dillen, Koen; Mitchell, Paul D; Van Looy, Tinne; Tollens, Eric

    2010-09-01

    During the early 1990s, the western corn rootworm, Diabrotica virgifera virgifera Le Conte (WCR), a maize pest, invaded the European continent. The continuous spread of the pest has introduced a new constraint into European maize production. As the damage caused by the invasive species is highly variable and different crop protection (CP) strategies are available, farmers' optimal strategies are not obvious. This study uses a simulation model to assess the competitiveness of different CP strategies in seven Central European countries. Results indicate a high degree of heterogeneity in the profitability of different CP strategies, depending on the production parameters in each country. In general, crop rotation and Bt maize offer the best solutions to farmers, but, in continuous (non-rotated) maize cultivation, chemical CP options may capture part of the market. For Austrian continuous maize production it is found that not deregulating Bt maize implies that farmers forego revenues of up to euro 59 ha(-1). In the presence of WCR, producing maize by an economically sound method requires incorporating country- and farm-specific characteristics into the decision framework. Also, not deregulating Bt maize has direct monetary consequences for many farmers that could influence total maize output and resistance management. (c) 2010 Society of Chemical Industry.

  6. Effect of Bt-cotton on chrysopids, ladybird beetles and their prey: aphids and whiteflies.

    Science.gov (United States)

    Mellet, M A; Schoeman, A S

    2007-06-01

    The effect of Bt-cotton, i.e. genetically modified cotton that contain genes expressing delta-endotoxin, on aphid, whitefly, chrysopid and coccinellid populations was determined with a two-year field study at a cotton farm near Marble Hall, South Africa. Although Bt-cotton is lepidopteran specific, non-lepidopteran arthropod populations may be indirectly influenced by the endotoxin. Abundance of aphid, whitefly, chrysopid and coccinellid populations and predator-prey interactions were used as measures to determine possible effects on the populations under investigation. The cultivation of Bt-cotton had no effect on aphid, whitefly, chrysopid or coccinellid abundance. Positive density dependent interactions occurred between aphids and coccinellids which were not influenced by Bt-cotton. A significant relationship between whitefly and coccinellid abundance, i.e. predator-prey reaction, occurred in the control and sprayed non-Bt cotton fields but was absent from the Bt-cotton fields.

  7. Valuing financial, health and environmental benefits of Bt cotton in Pakistan

    OpenAIRE

    Kouser, Shahzad; Qaim, Matin

    2012-01-01

    Data from a farm survey and choice experiment are used to value the benefits of Bt cotton in Pakistan. Unlike previous research on the economic impacts of Bt, which mostly concentrated on financial benefits in terms of gross margins, we also quantify and monetize positive externalities associated with technology adoption. Due to lower chemical pesticide use on Bt cotton plots, there are significant health advantages in terms of reduced incidence of acute pesticide poisoning, and environmental...

  8. Evidence of reduced arbuscular mycorrhizal fungal colonization in multiple lines of Bt maize.

    Science.gov (United States)

    Cheeke, Tanya E; Rosenstiel, Todd N; Cruzan, Mitchell B

    2012-04-01

    Insect-resistant Bacillus thuringiensis (Bt) maize is widely cultivated, yet few studies have examined the interaction of symbiotic arbuscular mycorrhizal fungi (AMF) with different lines of Bt maize. As obligate symbionts, AMF may be sensitive to genetic changes within a plant host. Previous evaluations of the impact of Bt crops on AMF have been inconsistent, and because most studies were conducted under disparate experimental conditions, the results are difficult to compare. We evaluate AMF colonization in nine Bt maize lines, differing in number and type of engineered trait, and five corresponding near-isogenic parental (P) base hybrids in greenhouse microcosms. Plants were grown in 50% local agricultural soil with low levels of fertilization, and AMF colonization was evaluated at 60 and 100 d. Nontarget effects of Bt cultivation on AMF colonization were tested in a subsequently planted crop, Glycine max, which was seeded into soil that had been preconditioned for 60 d with Bt or P maize. We found that Bt maize had lower levels of AMF colonization in their roots than did the non-Bt parental lines. However, reductions in AMF colonization were not related to the expression of a particular Bt protein. There was no difference in AMF colonization in G. max grown in the Bt- or P-preconditioned soil. These findings are the first demonstration of a reduction in AMF colonization in multiple Bt maize lines grown under the same experimental conditions and contribute to the growing body of knowledge examining the unanticipated effects of Bt crop cultivation on nontarget soil organisms.

  9. Cry1F Resistance in Fall Armyworm Spodoptera frugiperda: Single Gene versus Pyramided Bt Maize

    OpenAIRE

    Huang, Fangneng; Qureshi, Jawwad A.; Meagher, Robert L.; Reisig, Dominic D.; Head, Graham P.; Andow, David A.; Ni, Xinzi; Kerns, David; Buntin, G. David; Niu, Ying; Yang, Fei; Dangal, Vikash

    2014-01-01

    Evolution of insect resistance to transgenic crops containing Bacillus thuringiensis (Bt) genes is a serious threat to the sustainability of this technology. However, field resistance related to the reduced efficacy of Bt maize has not been documented in any lepidopteran pest in the mainland U.S. after 18 years of intensive Bt maize planting. Here we report compelling evidence of field resistance in the fall armyworm, Spodoptera frugiperda (J.E. Smith), to Cry1F maize (TC 3507) in the southea...

  10. Measuring the contribution of Bt cotton adoption to India's cotton yields leap:

    OpenAIRE

    Gruere, Guillaume P.; Sun, Yan

    2012-01-01

    While a number of empirical studies have demonstrated the role of Bt cotton adoption in increasing Indian cotton productivity at the farm level, there has been questioning around the overall contribution of Bt cotton to the average cotton yield increase observed these last ten years in India. This study examines the contribution of Bt cotton adoption to long- term average cotton yields in India using a panel data analysis of production variables in nine Indian cotton-producing states from 197...

  11. Enhanced depolarization temperature in 0.90NBT-0.05KBT-0.05BT ceramics induced by BT nanowires

    Science.gov (United States)

    Cao, W. P.; Li, W. L.; Feng, Y.; Xu, D.; Wang, W.; Hou, Y. F.; Zhang, T. D.; Fei, W. D.

    2015-03-01

    The depolarization temperature (Td) of piezoelectric materials is an important figure of merit for their application at elevated temperatures. This study focuses on the effect of BaTiO3 (BT) nanowires on Td and piezoelectric properties of morphotropic-phase-boundary 0.90NBT-0.05KBT-0.05BT ceramics. The results reveal that BaTiO3 nanowires can pin the domain wall, leading to the increase of coercive field (Ec) from 21.06 kV/cm to 34.99 kV/cm. The Td value of 0.90NBT-0.05KBT-0.05BT ceramics can be enhanced approximately 20 °C when using BT nanowires instead of BT solution as the raw material. Meanwhile, at the same polarization conditions, the piezoelectric constant of the ceramic added BT nanowires (172 pC/N) is decreased but still remains a larger value compared with those of other lead-free ceramics. The results imply that the addition of BT nanowires into NBT-KBT is a very effective route to improve Td.

  12. Bacillus thuringiensis Cry34Ab1/Cry35Ab1 interactions with western corn rootworm midgut membrane binding sites.

    Directory of Open Access Journals (Sweden)

    Huarong Li

    Full Text Available BACKGROUND: Bacillus thuringiensis (Bt Cry34Ab1/Cry35Ab1 are binary insecticidal proteins that are co-expressed in transgenic corn hybrids for control of western corn rootworm, Diabrotica virgifera virgifera LeConte. Bt crystal (Cry proteins with limited potential for field-relevant cross-resistance are used in combination, along with non-transgenic corn refuges, as a strategy to delay development of resistant rootworm populations. Differences in insect midgut membrane binding site interactions are one line of evidence that Bt protein mechanisms of action differ and that the probability of receptor-mediated cross-resistance is low. METHODOLOGY/PRINCIPAL FINDINGS: Binding site interactions were investigated between Cry34Ab1/Cry35Ab1 and coleopteran active insecticidal proteins Cry3Aa, Cry6Aa, and Cry8Ba on western corn rootworm midgut brush border membrane vesicles (BBMV. Competitive binding of radio-labeled proteins to western corn rootworm BBMV was used as a measure of shared binding sites. Our work shows that (125I-Cry35Ab1 binds to rootworm BBMV, Cry34Ab1 enhances (125I-Cry35Ab1 specific binding, and that (125I-Cry35Ab1 with or without unlabeled Cry34Ab1 does not share binding sites with Cry3Aa, Cry6Aa, or Cry8Ba. Two primary lines of evidence presented here support the lack of shared binding sites between Cry34Ab1/Cry35Ab1 and the aforementioned proteins: 1 No competitive binding to rootworm BBMV was observed for competitor proteins when used in excess with (125I-Cry35Ab1 alone or combined with unlabeled Cry34Ab1, and 2 No competitive binding to rootworm BBMV was observed for unlabeled Cry34Ab1 and Cry35Ab1, or a combination of the two, when used in excess with (125I-Cry3Aa, or (125I-Cry8Ba. CONCLUSIONS/SIGNIFICANCE: Combining two or more insecticidal proteins active against the same target pest is one tactic to delay the onset of resistance to either protein. We conclude that Cry34Ab1/Cry35Ab1 are compatible with Cry3Aa, Cry6Aa, or Cry8Ba

  13. SNS ønsker kommentarer om oplysninger fra Syngenta Seeds vedr forurening med Bt10 i Bt11-majsen ændrer konklusionerne i risikovurderingen. Zea mays (Bt11) . Supplerende informationer om Bt11 - evt. konsekvenser for tidligere vurderinger. Modtaget 04-05-2005, deadline 06-06-2005, svar 24-05-2005

    DEFF Research Database (Denmark)

    Kjellsson, Gøsta

    2012-01-01

    "Vedr. oplysningerne om iblanding af Bt-10 majsen i Bt-11 viser det tilsendte materiale, at Syngenta har undersøgt og fået bekræftet at undersøgelserne til grundlag for risikovurderingen blev foretaget på Bt-11 majs. DMU ser derfor ingen grund til at ændre konklusionerne i den tidligere...... risikovurdering af Bt-11 majsen. Imidlertid viser denne sag vigtigheden af at majspartierne også overvåges med hensyn til utilsigtet iblanding af andre genmodificerede majstyper."...

  14. 21 CFR 155.131 - Canned field corn.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Canned field corn. 155.131 Section 155.131 Food... Canned field corn. (a) Identity. (1) Canned field corn conforms to the definition and standard of... corn by § 155.130(a), except that the corn ingredient consists of succulent field corn or a mixture of...

  15. BT TOXIN IS NOT TAKEN UP FROM SOIL OR HYDROPONIC CULTURE BY CORN, CARROT, RADISH, OR TURNIP. (R826107)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  16. Validation of reference housekeeping genes for gene expression studies in western corn rootworm (Diabrotica virgifera virgifera.

    Directory of Open Access Journals (Sweden)

    Thaís Barros Rodrigues

    Full Text Available Quantitative Real-time PCR (qRT-PCR is a powerful technique to investigate comparative gene expression. In general, normalization of results using a highly stable housekeeping gene (HKG as an internal control is recommended and necessary. However, there are several reports suggesting that regulation of some HKGs is affected by different conditions. The western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae, is a serious pest of corn in the United States and Europe. The expression profile of target genes related to insecticide exposure, resistance, and RNA interference has become an important experimental technique for study of western corn rootworms; however, lack of information on reliable HKGs under different conditions makes the interpretation of qRT-PCR results difficult. In this study, four distinct algorithms (Genorm, NormFinder, BestKeeper and delta-CT and five candidate HKGs to genes of reference (β-actin; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; β-tubulin; RPS9, ribosomal protein S9; EF1a, elongation factor-1α were evaluated to determine the most reliable HKG under different experimental conditions including exposure to dsRNA and Bt toxins and among different tissues and developmental stages. Although all the HKGs tested exhibited relatively stable expression among the different treatments, some differences were noted. Among the five candidate reference genes evaluated, β-actin exhibited highly stable expression among different life stages. RPS9 exhibited the most similar pattern of expression among dsRNA treatments, and both experiments indicated that EF1a was the second most stable gene. EF1a was also the most stable for Bt exposure and among different tissues. These results will enable researchers to use more accurate and reliable normalization of qRT-PCR data in WCR experiments.

  17. 21 CFR 184.1857 - Corn sugar.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Corn sugar. 184.1857 Section 184.1857 Food and... Substances Affirmed as GRAS § 184.1857 Corn sugar. (a) Corn sugar (C6H12O6, CAS Reg. No. 50-99-7), commonly... monohydrate form and is produced by the complete hydrolysis of corn starch with safe and suitable acids or...

  18. 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.

  19. Assessing Potential Impact of Bt Eggplants on Non-Target Arthropods in the Philippines

    Science.gov (United States)

    Navasero, Mario V.; Candano, Randolph N.; Hautea, Desiree M.; Hautea, Randy A.; Shotkoski, Frank A.; Shelton, Anthony M.

    2016-01-01

    Studies on potential adverse effects of genetically engineered crops are part of an environmental risk assessment that is required prior to the commercial release of these crops. Of particular concern are non-target organisms (NTOs) that provide important ecosystem services. Here, we report on studies conducted in the Philippines over three cropping seasons with Bt eggplants expressing Cry1Ac for control of the eggplant fruit and shoot borer (EFSB), Leucinodes orbonalis, to examine potential effects on field abundance, community composition, structure and biodiversity of NTO’s, particularly non-target arthropod (NTA) communities. We document that many arthropod taxa are associated with Bt eggplants and their non-Bt comparators and that the number of taxa and their densities varied within season and across trials. However, we found few significant differences in seasonal mean densities of arthropod taxa between Bt and non-Bt eggplants. As expected, a lower abundance of lepidopteran pests was detected in Bt eggplants. Higher abundance of a few non-target herbivores was detected in non-Bt eggplants as were a few non-target beneficials that might control them. Principal Response Curve (PRC) analyses showed no statistically significant impact of Bt eggplants on overall arthropod communities through time in any season. Furthermore, we found no significant adverse impacts of Bt eggplants on species abundance, diversity and community dynamics, particularly for beneficial NTAs. These results support our previous studies documenting that Bt eggplants can effectively and selectively control the main pest of eggplant in Asia, the EFSB. The present study adds that it can do so without adverse effects on NTAs. Thus, Bt eggplants can be a foundational component for controlling EFSB in an Integrated Pest Management (IPM) program and dramatically reduce dependence on conventional insecticides. PMID:27798662

  20. Nitrogen Soil Testing for Corn in Virginia

    OpenAIRE

    Evanylo, Gregory K.; Alley, Marcus M., 1947-

    2009-01-01

    An adequate supply of plant-available nitrogen (N) is crucial for efficient corn production, and corn N requirements are greater than any other nutrient. This publication reviews the link between nitrogen and corn production, nitrogen behavior, soil testing, test procedures and recommendations.

  1. "King Corn": Teaching the Food Crisis

    Science.gov (United States)

    Swinehart, Tim

    2012-01-01

    "King Corn" is in so many ways the story of how government food policy has entirely remade the food landscape in the United States over the last 40 years. From the massive expansion of the number of acres of corn grown across the country, to the ever-increasing ways that corn is incorporated into the food production process, to the…

  2. Geographic information systems in corn rootworm management

    Science.gov (United States)

    Corn rootworms (Diabrotica spp. Coleoptera: Chrysomelidae) are serious pests of corn (Zea mays) in the United States and Europe. Control measures for corn rootworms (CRW) were historically based upon chemical pesticides and crop rotation. Pesticide use created environmental and economic concerns. In...

  3. Effects of replacing conventional corn silage with BMR corn silage

    Science.gov (United States)

    Previous research has shown that the (lignin reducing) brown mid-rib mutation in corn silage, which increases in vitro fiber digestibility, does not always improve fiber digestibility when fed as part of a TMR; however, feed intake and milk production are increased. The objectives of this experiment...

  4. Strong oviposition preference for Bt over non-Bt maize in Spodoptera frugiperda and its implications for the evolution of resistance.

    Science.gov (United States)

    Téllez-Rodríguez, Pilar; Raymond, Ben; Morán-Bertot, Ivis; Rodríguez-Cabrera, Lianet; Wright, Denis J; Borroto, Carlos G; Ayra-Pardo, Camilo

    2014-06-16

    Transgenic crops expressing Bt toxins have substantial benefits for growers in terms of reduced synthetic insecticide inputs, area-wide pest management and yield. This valuable technology depends upon delaying the evolution of resistance. The 'high dose/refuge strategy', in which a refuge of non-Bt plants is planted in close proximity to the Bt crop, is the foundation of most existing resistance management. Most theoretical analyses of the high dose/refuge strategy assume random oviposition across refugia and Bt crops. In this study we examined oviposition and survival of Spodoptera frugiperda across conventional and Bt maize and explored the impact of oviposition behavior on the evolution of resistance in simulation models. Over six growing seasons oviposition rates per plant were higher in Bt crops than in refugia. The Cry1F Bt maize variety retained largely undamaged leaves, and oviposition preference was correlated with the level of feeding damage in the refuge. In simulation models, damage-avoiding oviposition accelerated the evolution of resistance and either led to requirements for larger refugia or undermined resistance management altogether. Since larval densities affected oviposition preferences, pest population dynamics affected resistance evolution: larger refugia were weakly beneficial for resistance management if they increased pest population sizes and the concomitant degree of leaf damage. Damaged host plants have reduced attractiveness to many insect pests, and crops expressing Bt toxins are generally less damaged than conventional counterparts. Resistance management strategies should take account of this behavior, as it has the potential to undermine the effectiveness of existing practice, especially in the tropics where many pests are polyvoltinous. Efforts to bring down total pest population sizes and/or increase the attractiveness of damaged conventional plants will have substantial benefits for slowing the evolution of resistance.

  5. Transgenic Bt rice does not challenge host preference of the target pest of rice leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae.

    Directory of Open Access Journals (Sweden)

    Xiao Sun

    Full Text Available BACKGROUND: Transgenic Bt rice line T2A-1 expresses a synthesized cry2A gene that shows high resistance to Lepidoptera pests, including Cnaphalocrocis medinalis (Guenée (Lepidoptera: Pyralidae. Plant volatile orientation cues and the physical characteristics of the leaf surface play key roles in host location or host-plant acceptance of phytophagous insects. These volatile compounds and physical traits may become altered in Bt rice and it is not known whether this influences the behavior of C. medinalis when searching for oviposition sites. RESULTS: The results of electronic nose analysis showed that the Radar map of Bt rice cultivars was analogous to the non- Bt rice cultivars at each growing stage. PCA analysis was able to partly discriminate between some of the Bt vs. non-Bt rice sensors, but could not to separate Bt cultivars from non-Bt cultivars. The total ion chromatogram between Bt and non-Bt rice cultivars at the seedling, booting and tillering stages were similar and 25 main compounds were identified by GC-MS. For most compounds, there was no significant difference in compound quantities between Bt and non-Bt rice cultivars at equivalent growth stages. The densities of the tubercle papicles and the trichomes on the upper and lower surfaces were statistically equal in Bt and non-Bt rice. The target pest, C. medinalis, was attracted to host rice plants, but it could not distinguish between the transgenic and the isogenic rice lines. CONCLUSIONS: There were no significant differences between the Bt rice line, T2A-1 and the non-Bt rice for volatiles produced or in its physical characteristics and there were no negative impacts on C. medinalis oviposition behavior. These results add to the mounting evidence that Bt rice has no negative impact on the target insect oviposition behavior.

  6. Transgenic Bt Rice Does Not Challenge Host Preference of the Target Pest of Rice Leaffolder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

    Science.gov (United States)

    Sun, Xiao; Zhou, Wen; Liu, Hao; Zhang, Aijun; Ai, Chao-Ren; Zhou, Shuang-Shuang; Zhou, Chang-Xiang; Wang, Man-Qun

    2013-01-01

    Background Transgenic Bt rice line T2A-1 expresses a synthesized cry2A gene that shows high resistance to Lepidoptera pests, including Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae). Plant volatile orientation cues and the physical characteristics of the leaf surface play key roles in host location or host-plant acceptance of phytophagous insects. These volatile compounds and physical traits may become altered in Bt rice and it is not known whether this influences the behavior of C. medinalis when searching for oviposition sites. Results The results of electronic nose analysis showed that the Radar map of Bt rice cultivars was analogous to the non- Bt rice cultivars at each growing stage. PCA analysis was able to partly discriminate between some of the Bt vs. non-Bt rice sensors, but could not to separate Bt cultivars from non-Bt cultivars. The total ion chromatogram between Bt and non-Bt rice cultivars at the seedling, booting and tillering stages were similar and 25 main compounds were identified by GC-MS. For most compounds, there was no significant difference in compound quantities between Bt and non-Bt rice cultivars at equivalent growth stages. The densities of the tubercle papicles and the trichomes on the upper and lower surfaces were statistically equal in Bt and non-Bt rice. The target pest, C. medinalis, was attracted to host rice plants, but it could not distinguish between the transgenic and the isogenic rice lines. Conclusions There were no significant differences between the Bt rice line, T2A-1 and the non-Bt rice for volatiles produced or in its physical characteristics and there were no negative impacts on C. medinalis oviposition behavior. These results add to the mounting evidence that Bt rice has no negative impact on the target insect oviposition behavior. PMID:24244410

  7. Does Bt rice pose risks to non-target arthropods? Results of a meta-analysis in China.

    Science.gov (United States)

    Dang, Cong; Lu, Zengbin; Wang, Long; Chang, Xuefei; Wang, Fang; Yao, Hongwei; Peng, Yufa; Stanley, David; Ye, Gongyin

    2017-08-01

    Transgenic Bt rice expressing the insecticidal proteins derived from Bacillus thuringiensis Berliner (Bt) has been developed since 1989. Their ecological risks towards non-target organisms have been investigated; however, these studies were conducted individually, yielding uncertainty regarding potential agroecological risks associated with large-scale deployment of Bt rice lines. Here, we developed a meta-analysis of the existing literature to synthesize current knowledge of the impacts of Bt rice on functional arthropod guilds, including herbivores, predators, parasitoids and detritivores in laboratory and field studies. Laboratory results indicate Bt rice did not influence survival rate and developmental duration of herbivores, although exposure to Bt rice led to reduced egg laying, which correctly predicted their reduced abundance in Bt rice agroecosystems. Similarly, consuming prey exposed to Bt protein did not influence survival, development or fecundity of predators, indicating constant abundances of predators in Bt rice fields. Compared to control agroecosystems, parasitoid populations decreased slightly in Bt rice cropping systems, while detritivores increased. We draw two inferences. One, laboratory studies of Bt rice showing effects on ecological functional groups are mainly either consistent with or more conservative than results of field studies, and two, Bt rice will pose negligible risks to the non-target functional guilds in future large-scale Bt rice agroecosystems in China. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  8. Utilisation of corn (Zea mays) bran and corn fiber in the production of food components.

    Science.gov (United States)

    Rose, Devin J; Inglett, George E; Liu, Sean X

    2010-04-30

    The milling of corn for the production of food constituents results in a number of low-value co-products. Two of the major co-products produced by this operation are corn bran and corn fiber, which currently have low commercial value. This review focuses on current and prospective research surrounding the utilization of corn fiber and corn bran in the production of potentially higher-value food components. Corn bran and corn fiber contain potentially useful components that may be harvested through physical, chemical or enzymatic means for the production of food ingredients or additives, including corn fiber oil, corn fiber gum, cellulosic fiber gels, xylo-oligosaccharides and ferulic acid. Components of corn bran and corn fiber may also be converted to food chemicals such as vanillin and xylitol. Commercialization of processes for the isolation or production of food products from corn bran or corn fiber has been met with numerous technical challenges, therefore further research that improves the production of these components from corn bran or corn fiber is needed.

  9. Advances in managing pest resistance to Bt crops: Pyramids and seed mixtures

    Science.gov (United States)

    Transgenic crops producing toxins from the soil bacterium Bacillus thuringiensis (Bt) have been widely used for the control of insect pests during the last 20 years. Although Bt crops have provided significant environmental and economic benefits, sustainable use of these crops is threatened by the r...

  10. Effects of ensiling of Bacillus thuringiensis (Bt) maize (MON810) on ...

    African Journals Online (AJOL)

    ajl yemi

    2011-11-30

    Nov 30, 2011 ... Cry1Ab protein, neutral detergent fiber, acid detergent fiber, acid detergent lignin and crude protein. Silage from two of the Bt maize varieties had ... Mechanical disruption of cell walls and membranes during ... study was to determine the effects of ensiling Bt maize on concentration of the Cry1Ab protein and ...

  11. Interpreting the Relationships between TOEFL iBT Scores and GPA: Language Proficiency, Policy, and Profiles

    Science.gov (United States)

    Ginther, April; Yan, Xun

    2018-01-01

    This study examines the predictive validity of the TOEFL iBT with respect to academic achievement as measured by the first-year grade point average (GPA) of Chinese students at Purdue University, a large, public, Research I institution in Indiana, USA. Correlations between GPA, TOEFL iBT total and subsection scores were examined on 1990 mainland…

  12. Delta's Key to the TOEFL iBT[R]: Advanced Skill Practice. Revised Edition

    Science.gov (United States)

    Gallagher, Nancy

    2012-01-01

    Delta's Key to the TOEFL iBT: Advanced Skill Practice is a revised and updated edition of Delta's Key to the Next Generation TOEFL Test. Since the introduction of the TOEFL iBT in 2005, there have been significant changes to some of the test questions, particularly the integrated writing and integrated speaking tasks. The new 2011 edition of…

  13. Application of Cry1Ab/Ac Bt strip for screening of resistance for ...

    African Journals Online (AJOL)

    In this study, the efficacy of using Cry1Ab/Ac Bt strip for detecting Maruca resistant transgene in transgenic cowpea was systematically investigated for the first time through field derived progenies. The results show ... Keywords: Bacillus thuriengiensis, Cry1Ab/Ac Bt strips, transgenic cowpea, Maruca vitrata. African Journal of ...

  14. screening of new isolates of bt and cloning of their dna amplicons

    African Journals Online (AJOL)

    NEMAPPA

    2012-09-18

    Sep 18, 2012 ... Nine new indigenous isolates of Bacillus thuringiensis (Bt) were characterized for their colony type, crystal inclusion and toxicity ... from new isolates of Bt. New gene sequences encoding more active toxins could be ..... (2009). Toxicity of a Bacillus thuringiensis israelensis-like strain against Spodoptera ...

  15. Relevance of Bt toxin interaction studies for environmental risk assessment of genetically modified crops

    NARCIS (Netherlands)

    Schrijver, De Adinda; Clercq, De Patrick; Maagd, de R.A.; Frankenhuyzen, van Kees

    2015-01-01

    In recent years, different Bacillus thuringiensis (Bt) toxin-encoding genes have been combined or 'stacked' in genetically modified (GM) crops. Synergism between Bt proteins may occur and thereby increase the impact of the stacked GM event on nontarget invertebrates compared to plants expressing

  16. Testing public Bt maize events for control of stem borers in the first ...

    African Journals Online (AJOL)

    Transgenic maize (Zea mays L), developed using modified genes from the bacterium Bacillus thuringiensis (Bt), controls stem borers without observable negative effects to humans, livestock or the environment, and is now sown on 134 million hectares globally. Bt maize could contribute to increasing maize production in ...

  17. Multi-Toxin Resistance Enables Pink Bollworm Survival on Pyramided Bt Cotton.

    Science.gov (United States)

    Fabrick, Jeffrey A; Unnithan, Gopalan C; Yelich, Alex J; DeGain, Ben; Masson, Luke; Zhang, Jie; Carrière, Yves; Tabashnik, Bruce E

    2015-11-12

    Transgenic crops producing Bacillus thuringiensis (Bt) proteins kill key insect pests, providing economic and environmental benefits. However, the evolution of pest resistance threatens the continued success of such Bt crops. To delay or counter resistance, transgenic plant "pyramids" producing two or more Bt proteins that kill the same pest have been adopted extensively. Field populations of the pink bollworm (Pectinophora gossypiella) in the United States have remained susceptible to Bt toxins Cry1Ac and Cry2Ab, but field-evolved practical resistance to Bt cotton producing Cry1Ac has occurred widely in India. Here we used two rounds of laboratory selection to achieve 18,000- to 150,000-fold resistance to Cry2Ab in pink bollworm. Inheritance of resistance to Cry2Ab was recessive, autosomal, conferred primarily by one locus, and independent of Cry1Ac resistance. We created a strain with high resistance to both toxins by crossing the Cry2Ab-resistant strain with a Cry1Ac-resistant strain, followed by one selection with Cry2Ab. This multi-toxin resistant strain survived on field-collected Bt cotton bolls producing both toxins. The results here demonstrate the risk of evolution of resistance to pyramided Bt plants, particularly when toxins are deployed sequentially and refuges are scarce, as seen with Bt cotton and pink bollworm in India.

  18. The natural refuge policy for Bt cotton (Gossypium L. in Pakistan – a situation analysis

    Directory of Open Access Journals (Sweden)

    Muhammad Sajjad Ali

    2013-07-01

    Full Text Available Bt cotton (event Cry1Ac was formally commercialized in Pakistan in 2010. However, there has been an increasing trend of planting unauthorized Bt cotton germplasm in farmers' fields since 2003 with a high rate of adoption in the core cotton areas especially in the province Punjab. The transgenic cotton technology has provided the growers with substantial economic benefits and has reduced their dependence on pesticides for pest control, especially against Helicoverpa armigera (Hubner. However, keeping in view the capacity of this insect to develop resistance against novel chemical formulations, it is easily speculated that Bt toxin, too, is no exception. Refuge crop policy for mono transgenic crop events has helped in delaying the rate of resistance evolution in the target pests. Thus, in Pakistan, where planting of structured refuge crops along Bt cotton fields is not mandatory, the effectiveness and durability of Bt cotton technology may decrease due to a number of factors which are discussed in this review.

  19. The end of a myth – Bt (Cry1Ab maize does not harm green lacewings

    Directory of Open Access Journals (Sweden)

    Joerg eRomeis

    2014-08-01

    Full Text Available A concern with Bt-transgenic insect-resistant plants is their potential to harm non-target organisms. Early studies reported that Cry1Ab-producing Bt maize and purified Cry1Ab harmed larvae of the green lacewing, Chrysoperla carnea. Although these effects could not be confirmed in subsequent studies, some authors still refer to them as evidence that Bt maize harms beneficial species. We provide a comprehensive review of the studies evaluating the effects of Bt (Cry1Ab maize on C. carnea. The evidence indicates that this important predator is not affected by Bt maize or by the produced Cry1Ab protein. We discuss how conceptual models can assist environmental risk assessments, and we emphasize the importance of robust and reproducible studies.

  20. The end of a myth-Bt (Cry1Ab) maize does not harm green lacewings.

    Science.gov (United States)

    Romeis, Jörg; Meissle, Michael; Naranjo, Steven E; Li, Yunhe; Bigler, Franz

    2014-01-01

    A concern with Bt-transgenic insect-resistant plants is their potential to harm non-target organisms. Early studies reported that Cry1Ab-producing Bt maize and purified Cry1Ab harmed larvae of the green lacewing, Chrysoperla carnea. Although these effects could not be confirmed in subsequent studies, some authors still refer to them as evidence that Bt maize harms beneficial species. We provide a comprehensive review of the studies evaluating the effects of Bt (Cry1Ab) maize on C. carnea. The evidence indicates that this important predator is not affected by Bt maize or by the produced Cry1Ab protein. We discuss how conceptual models can assist environmental risk assessments, and we emphasize the importance of robust and reproducible studies.

  1. The end of a myth—Bt (Cry1Ab) maize does not harm green lacewings

    Science.gov (United States)

    Romeis, Jörg; Meissle, Michael; Naranjo, Steven E.; Li, Yunhe; Bigler, Franz

    2014-01-01

    A concern with Bt-transgenic insect-resistant plants is their potential to harm non-target organisms. Early studies reported that Cry1Ab-producing Bt maize and purified Cry1Ab harmed larvae of the green lacewing, Chrysoperla carnea. Although these effects could not be confirmed in subsequent studies, some authors still refer to them as evidence that Bt maize harms beneficial species. We provide a comprehensive review of the studies evaluating the effects of Bt (Cry1Ab) maize on C. carnea. The evidence indicates that this important predator is not affected by Bt maize or by the produced Cry1Ab protein. We discuss how conceptual models can assist environmental risk assessments, and we emphasize the importance of robust and reproducible studies. PMID:25161661

  2. Our Mother Corn. Teacher's Guide.

    Science.gov (United States)

    Mathers, Sherry; And Others

    Designed to accompany the preceding student text (which deals with the role of corn in the Seneca, Pawnee, and Hopi tribes), the teaching guide contains a suggested sequence of activities and needed supplementary information along with an indication of the student text they follow. Sections include: farming notes; basic needs activities; house…

  3. Does Bt rice pose risks to non-target arthropods? Results of a meta-analysis in China

    Science.gov (United States)

    Transgenic Bt rice expressing the protoxin proteins derived from Bacillus thuringiensis Berliner (Bt) have been developed since 1989. Their ecological risks toward non-target organisms have been investigated. However, these studies were conducted individually, yielding inconsistent conclusions and u...

  4. 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.

  5. The U2U Corn Growing Degree Day tool: Tracking corn growth across the US Corn Belt

    Directory of Open Access Journals (Sweden)

    James R. Angel

    2017-01-01

    Full Text Available The Corn Growing Degree Day (Corn GDD tool is a web-based product that can provide decision support on a variety of issues throughout the entire growing season by integrating current conditions, historical climate data, and projections of Corn GDD through the end of the growing season based on both National Weather Service computer model forecasts and climatology. The Corn GDD tool can help agricultural producers make a variety of important decisions before and during the growing season. This support can include: assessing the risk of early and late frosts and freezes that can cause crop damage; comparing corn hybrid maturity requirements and Corn GDD projections to select seed varieties and plan activities such as spraying; guiding marketing decisions based on historical and projected Corn GDDs when considering forward crop pricing (i.e., futures market. The Corn GDD tool provides decision support for corn producers in the central U.S. corn-producing states. Survey results, web statistics, and user feedback indicate that this tool is being actively used by decision makers.

  6. A high-throughput liquid bead array-based screening technology for Bt presence in GMO manipulation.

    Science.gov (United States)

    Fu, Wei; Wang, Huiyu; Wang, Chenguang; Mei, Lin; Lin, Xiangmei; Han, Xueqing; Zhu, Shuifang

    2016-03-15

    The number of species and planting areas of genetically modified organisms (GMOs) has been rapidly developed during the past ten years. For the purpose of GMO inspection, quarantine and manipulation, we have now devised a high-throughput Bt-based GMOs screening method based on the liquid bead array. This novel method is based on the direct competitive recognition between biotinylated antibodies and beads-coupled antigens, searching for Bt presence in samples if it contains Bt Cry1 Aa, Bt Cry1 Ab, Bt Cry1 Ac, Bt Cry1 Ah, Bt Cry1 B, Bt Cry1 C, Bt Cry1 F, Bt Cry2 A, Bt Cry3 or Bt Cry9 C. Our method has a wide GMO species coverage so that more than 90% of the whole commercialized GMO species can be identified throughout the world. Under our optimization, specificity, sensitivity, repeatability and availability validation, the method shows a high specificity and 10-50 ng/mL sensitivity of quantification. We then assessed more than 1800 samples in the field and food market to prove capacity of our method in performing a high throughput screening work for GMO manipulation. Our method offers an applicant platform for further inspection and research on GMO plants. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Impact of 9 years of Bt-maize cultivation on the distribution of maize viruses.

    Science.gov (United States)

    Achon, Maria Angeles; Alonso-Dueñas, Natalia

    2009-06-01

    This study assesses the effect of Bt-maize on the distribution of maize viruses. Random surveys were conducted in Spain between 2001 and 2006 to evaluate the occurrence of maize viruses in Bt-maize cultivation areas and in areas where this crop had not been introduced. Maize dwarf mosaic virus (MDMV) was the predominant virus in Bt-areas, and Maize rough dwarf virus (MRDV) was the most predominant one in non-Bt-areas, with MRDV an emergent virus in both types of areas. A decline in the occurrence of MDMV and an increase in that of Sugarcane mosaic virus was observed in Bt-areas. Additionally, data obtained over 6 years in experimental fields showed non-significant differences between the infection rates exhibited by two generations of Bt varieties and the non-transformed isogenics varieties for any of the viruses. Our data suggest that differences in virus distribution are linked to the genetic background of the maize varieties and the distribution of virus reservoirs rather than to Bt-maize cultivation.

  8. Aphid honeydew quality as a food source for parasitoids is maintained in Bt cotton.

    Science.gov (United States)

    Hagenbucher, Steffen; Wäckers, Felix L; Romeis, Jörg

    2014-01-01

    Bt-transgenic cotton has proven to be highly efficient in controlling key lepidopteran pests. One concern with the deployment of Bt cotton varieties is the potential proliferation of non-target pests. We previously showed that Bt cotton contained lower concentrations of insecticidal terpenoids as a result of reduced caterpillar damage, which benefited the aphid Aphis gossypii. It is thus important that non-target herbivores are under biological control in Bt cotton fields. The induction or lack of induction of terpenoids could also influence the quality of aphid honeydew, an important food source for beneficial insects. We therefore screened A. gossypii honeydew for cotton terpenoids, that are induced by caterpillars but not the aphids. We then tested the influence of induced insect-resistance of cotton on honeydew nutritional quality for the aphid parasitoid Lysiphlebus testaceipes and the whitefly parasitoid Eretmocerus eremicus. We detected the cotton terpenoids gossypol and hemigossypolone in A. gossypii honeydew. Although a feeding assay demonstrated that gossypol reduced the longevity of both parasitoid species in a non-linear, dose-dependent manner, the honeydew was capable of sustaining parasitoid longevity and reproduction. The level of caterpillar damage to Bt and non-Bt cotton had no impact on the quality of honeydew for the parasitoids.These results indicate that the nutritional quality of honeydew is maintained in Bt cotton and is not influenced by induced insect resistance.

  9. Aphid honeydew quality as a food source for parasitoids is maintained in Bt cotton.

    Directory of Open Access Journals (Sweden)

    Steffen Hagenbucher

    Full Text Available Bt-transgenic cotton has proven to be highly efficient in controlling key lepidopteran pests. One concern with the deployment of Bt cotton varieties is the potential proliferation of non-target pests. We previously showed that Bt cotton contained lower concentrations of insecticidal terpenoids as a result of reduced caterpillar damage, which benefited the aphid Aphis gossypii. It is thus important that non-target herbivores are under biological control in Bt cotton fields. The induction or lack of induction of terpenoids could also influence the quality of aphid honeydew, an important food source for beneficial insects. We therefore screened A. gossypii honeydew for cotton terpenoids, that are induced by caterpillars but not the aphids. We then tested the influence of induced insect-resistance of cotton on honeydew nutritional quality for the aphid parasitoid Lysiphlebus testaceipes and the whitefly parasitoid Eretmocerus eremicus. We detected the cotton terpenoids gossypol and hemigossypolone in A. gossypii honeydew. Although a feeding assay demonstrated that gossypol reduced the longevity of both parasitoid species in a non-linear, dose-dependent manner, the honeydew was capable of sustaining parasitoid longevity and reproduction. The level of caterpillar damage to Bt and non-Bt cotton had no impact on the quality of honeydew for the parasitoids.These results indicate that the nutritional quality of honeydew is maintained in Bt cotton and is not influenced by induced insect resistance.

  10. New Coll–HA/BT composite materials for hard tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Zanfir, Andrei Vlad [Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Material Science, “Politehnica” University of Bucharest, 1-7 Gh. Polizu Street, RO-011061 Bucharest (Romania); Voicu, Georgeta, E-mail: getav2001@yahoo.co.uk [Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Material Science, “Politehnica” University of Bucharest, 1-7 Gh. Polizu Street, RO-011061 Bucharest (Romania); Busuioc, Cristina; Jinga, Sorin Ion [Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Material Science, “Politehnica” University of Bucharest, 1-7 Gh. Polizu Street, RO-011061 Bucharest (Romania); Albu, Madalina Georgiana [Department of Collagen, Branch of Leather and Footwear Research, National Institute of Research and Development for Textile and Leather, 93 I. Minulescu Street, RO-031215 Bucharest (Romania); Iordache, Florin [Department of Fetal and Adult Stem Cell Therapy, “Nicolae Simionescu” Institute of Cellular Biology and Pathology of Romanian Academy, 8 B.P. Hasdeu Street, RO-050568 Bucharest (Romania)

    2016-05-01

    The integration of ceramic powders in composite materials for bone scaffolds can improve the osseointegration process. This work was aimed to the synthesis and characterization of new collagen–hydroxyapatite/barium titanate (Coll–HA/BT) composite materials starting from barium titanate (BT) nanopowder, hydroxyapatite (HA) nanopowder and collagen (Coll) gel. BT nanopowder was produced by combining two wet-chemical approaches, sol–gel and hydrothermal methods. The resulting materials were characterized in terms of phase composition and microstructure by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. Moreover, the biocompatibility and bioactivity of the composite materials were assessed by in vitro tests. The synthesized BT particles exhibit an average size of around 35 nm and a spherical morphology, with a pseudo-cubic or tetragonal symmetry. The diffraction spectra of Coll–HA and Coll–HA/BT composite materials indicate a pronounced interaction between Col and the mineral phases, meaning a good mineralization of Col fibres. As well, the in vitro tests highlight excellent osteoinductive properties for all biological samples, especially for Coll–HA/BT composite materials, fact that can be attributed to the ferromagnetic properties of BT. - Highlights: • Collagen–hydroxyapatite/barium titanate composite materials were synthesized. • Barium titanate was produced by combining the sol–gel and hydrothermal methods. • The in vitro tests highlight excellent osteoinductive properties for all samples.

  11. Managing fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), with Bt maize and insecticides in southern Brazil.

    Science.gov (United States)

    Burtet, Leonardo M; Bernardi, Oderlei; Melo, Adriano A; Pes, Maiquel P; Strahl, Thiago T; Guedes, Jerson Vc

    2017-12-01

    Maize plants expressing insecticidal proteins of Bacillus thuringiensis are valuable options for managing fall armyworm (FAW), Spodoptera frugiperda, in Brazil. However, control failures were reported, and therefore insecticides have been used to control this species. Based on these, we evaluated the use of Bt maize and its integration with insecticides against FAW in southern Brazil. Early-planted Agrisure TL, Herculex, Optimum Intrasect and non-Bt maize plants were severely damaged by FAW and required up to three insecticidal sprays. In contrast, YieldGard VT Pro, YieldGard VT Pro 3, PowerCore, Agrisure Viptera and Agrisure Viptera 3 showed little damage and did not require insecticides. Late-planted Bt maize plants showed significant damage by FAW and required up to four sprays, with the exceptions of Agrisure Viptera and Agrisure Viptera 3. Exalt (first and second sprays); Lannate + Premio (first spray) and Avatar (second spray); and Karate + Match (first spray) and Ampligo (second spray) were the most effective insecticides against FAW larvae in Bt and non-Bt maize. Maize plants expressing Cry proteins exhibited FAW control failures in southern Brazil, necessitating insecticidal sprays. In contrast, Bt maize containing the Vip3Aa20 protein remained effective against FAW. However, regardless of the insecticide used against FAW surviving on Bt maize, grain yields were similar. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  12. Multi Stakeholders' Attitudes toward Bt rice in Southwest, Iran: Application of TPB and Multi Attribute Models.

    Science.gov (United States)

    Ghoochani, Omid M; Ghanian, Mansour; Baradaran, Masoud; Azadi, Hossein

    2017-03-01

    Organisms that have been genetically engineered and modified (GM) are referred to as genetically modified organisms (GMOs). Bt crops are plants that have been genetically modified to produce certain proteins from the soil bacteria Bacillus thuringiensis (Bt), which makes these plants resistant to certain lepidopteran and coleopteran species. Genetically Modified (GM) rice was produced in 2006 by Iranian researchers from Tarom Mowla'ii and has since been called 'Bt rice'. As rice is an important source of food for over 3 billion inhabitants on Earth, this study aims to use a correlational survey in order to shed light on the predicting factors relating to the extent of stakeholders' behavioral intentions towards Bt rice. It is assumed and the results confirm that "attitudes toward GM crops" can be used as a bridge in the Attitude Model and the Behavioral Intention Model in order to establish an integrated model. To this end, a case study was made of the Southwest part of Iran in order to verify this research model. This study also revealed that as a part of the integrated research framework in the Behavior Intention Model both constructs of attitude and the subjective norm of the respondents serve as the predicting factors of stakeholders' intentions of working with Bt rice. In addition, the Attitude Model, as the other part of the integrated research framework, showed that the stakeholders' attitudes toward Bt rice can only be determined by the perceived benefits (e.g. positive outcomes) of Bt rice.

  13. Effects of Bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yongbo, E-mail: liuyb@craes.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Liu, Fang [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Wang, Chao [Pearl River Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou 510380 (China); Quan, Zhanjun [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Li, Junsheng, E-mail: lijsh@creas.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)

    2016-09-15

    The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch. Cultivation of Bt-transgenic rice had no effects on zooplankton communities. Phytoplankton abundance and biodiversity were not significantly different between transgenic and non-transgenic rice fields in 2013; however, phytoplankton were more abundant in the transgenic rice field than in the non-transgenic rice field in 2014. Water quality and rice type explained 65.9% and 12.8% of this difference in 2014, respectively. Phytoplankton and zooplankton were more abundant in mid- and downstream, than upstream, locations in the ditch, an effect that we attribute to water quality differences. Thus, the release of Bt toxins into field water during the cultivation of transgenic crops had no direct negative effects on plankton community composition, but indirect effects that alter environmental conditions should be taken into account during the processes of management planning and policymaking. - Highlights: • We detect fusion Cry1Ab/1Ac proteins from Bt rice entering into aquatic ecosystems. • Bt-transgenic rice cultivation have no significant effect on zooplankton community. • Bt-transgenic rice cultivation have indirect effect on phytoplankton community. • Water quality explains the difference of plankton communities in adjacent ditches.

  14. Effects of Bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches

    International Nuclear Information System (INIS)

    Liu, Yongbo; Liu, Fang; Wang, Chao; Quan, Zhanjun; Li, Junsheng

    2016-01-01

    The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch. Cultivation of Bt-transgenic rice had no effects on zooplankton communities. Phytoplankton abundance and biodiversity were not significantly different between transgenic and non-transgenic rice fields in 2013; however, phytoplankton were more abundant in the transgenic rice field than in the non-transgenic rice field in 2014. Water quality and rice type explained 65.9% and 12.8% of this difference in 2014, respectively. Phytoplankton and zooplankton were more abundant in mid- and downstream, than upstream, locations in the ditch, an effect that we attribute to water quality differences. Thus, the release of Bt toxins into field water during the cultivation of transgenic crops had no direct negative effects on plankton community composition, but indirect effects that alter environmental conditions should be taken into account during the processes of management planning and policymaking. - Highlights: • We detect fusion Cry1Ab/1Ac proteins from Bt rice entering into aquatic ecosystems. • Bt-transgenic rice cultivation have no significant effect on zooplankton community. • Bt-transgenic rice cultivation have indirect effect on phytoplankton community. • Water quality explains the difference of plankton communities in adjacent ditches.

  15. Indian Bt Cotton Varieties Do Not Affect the Performance of Cotton Aphids

    Science.gov (United States)

    Lawo, Nora C.; Wäckers, Felix L.; Romeis, Jörg

    2009-01-01

    Cotton varieties expressing Cry proteins derived from the soil bacterium Bacillus thuringiensis (Bt) are grown worldwide for the management of pest Lepidoptera. To prevent non-target pest outbreaks and to retain the biological control function provided by predators and parasitoids, the potential risk that Bt crops may pose to non-target arthropods is addressed prior to their commercialization. Aphids play an important role in agricultural systems since they serve as prey or host to a number of predators and parasitoids and their honeydew is an important energy source for several arthropods. To explore possible indirect effects of Bt crops we here examined the impact of Bt cotton on aphids and their honeydew. In climate chambers we assessed the performance of cotton aphids, Aphis gossypii Glover (Hemiptera: Aphididae) when grown on three Indian Bt (Cry1Ac) cotton varieties (MECH 12, MECH 162, MECH 184) and their non-transformed near isolines. Furthermore, we examined whether aphids pick up the Bt protein and analyzed the sugar composition of aphid honeydew to evaluate its suitability for honeydew-feeders. Plant transformation did not have any influence on aphid performance. However, some variation was observed among the three cotton varieties which might partly be explained by the variation in trichome density. None of the aphid samples contained Bt protein. As a consequence, natural enemies that feed on aphids are not exposed to the Cry protein. A significant difference in the sugar composition of aphid honeydew was detected among cotton varieties as well as between transformed and non-transformed plants. However, it is questionable if this variation is of ecological relevance, especially as honeydew is not the only sugar source parasitoids feed on in cotton fields. Our study allows the conclusion that Bt cotton poses a negligible risk for aphid antagonists and that aphids should remain under natural control in Bt cotton fields. PMID:19279684

  16. Pest Control in Corn and Soybeans: Weeds - Insects - Diseases.

    Science.gov (United States)

    Doersch, R. E.; And Others

    This document gives the characteristics and application rates for herbicides used to control annual weeds in corn, annual and perennial broadleaf weeds in corn, quackgrass and yellow nutsedge in corn, and annual weeds in soybeans. It also gives insecticide use information for corn and soybeans. A brief discussion of disease control in corn and…

  17. 7 CFR 810.401 - Definition of corn.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Definition of corn. 810.401 Section 810.401... GRAIN United States Standards for Corn Terms Defined § 810.401 Definition of corn. Grain that consists of 50 percent or more of whole kernels of shelled dent corn and/or shelled flint corn (Zea mays L...

  18. Production and Partial Characterization of Alpha-Amylase from Corn ...

    African Journals Online (AJOL)

    Corn pomace, a by-product of corn from “ogi” production was used as a substrate for the production of alpha-amylase by a corn fermenting strain of Bacillus licheniformis ATCC 4527. The corn pomace was fortified with potassium phosphate, magnesium sulphate and 2% w/v glucose to produce corn pomace basal medium, ...

  19. Life-History Traits of Spodoptera frugiperda Populations Exposed to Low-Dose Bt Maize.

    Science.gov (United States)

    Sousa, Fernanda F; Mendes, Simone M; Santos-Amaya, Oscar F; Araújo, Octávio G; Oliveira, Eugenio E; Pereira, Eliseu J G

    2016-01-01

    Exposure to Bacillus thuringiensis (Bt) toxins in low- and moderate-dose transgenic crops may induce sublethal effects and increase the rate of Bt resistance evolution, potentially compromising control efficacy against target pests. We tested this hypothesis using the fall armyworm Spodoptera frugiperda, a major polyphagous lepidopteran pest relatively tolerant to Bt notorious for evolving field-relevant resistance to single-gene Bt maize. Late-instar larvae were collected from Bt Cry1Ab and non-Bt maize fields in five locations in Brazil, and their offspring was compared for survival, development, and population growth in rearing environment without and with Cry1Ab throughout larval development. Larval survival on Cry1Ab maize leaves varied from 20 to 80% among the populations. Larvae reared on Cry1Ab maize had seven-day delay in development time in relation to control larvae, and such delay was shorter in offspring of armyworms from Cry1Ab maize. Population growth rates were 50-70% lower for insects continuously exposed to Cry1Ab maize relative to controls, showing the population-level effect of Cry1Ab, which varied among the populations and prior exposure to Cry1Ab maize in the field. In three out of five populations, armyworms derived from Bt maize reared on Cry1Ab maize showed higher larval weight, faster larval development and better reproductive performance than the armyworms derived from non-Bt maize, and one of these populations showed better performance on both Cry1Ab and control diets, indicating no fitness cost of the resistance trait. Altogether, these results indicate that offspring of armyworms that developed on field-grown, single-gene Bt Cry1Ab maize had reduced performance on Cry1Ab maize foliage in two populations studied, but in other three populations, these offspring had better overall performance on the Bt maize foliage than that of the armyworms from non-Bt maize fields, possibly because of Cry1Ab resistance alleles in these populations

  20. Life-History Traits of Spodoptera frugiperda Populations Exposed to Low-Dose Bt Maize.

    Directory of Open Access Journals (Sweden)

    Fernanda F Sousa

    Full Text Available Exposure to Bacillus thuringiensis (Bt toxins in low- and moderate-dose transgenic crops may induce sublethal effects and increase the rate of Bt resistance evolution, potentially compromising control efficacy against target pests. We tested this hypothesis using the fall armyworm Spodoptera frugiperda, a major polyphagous lepidopteran pest relatively tolerant to Bt notorious for evolving field-relevant resistance to single-gene Bt maize. Late-instar larvae were collected from Bt Cry1Ab and non-Bt maize fields in five locations in Brazil, and their offspring was compared for survival, development, and population growth in rearing environment without and with Cry1Ab throughout larval development. Larval survival on Cry1Ab maize leaves varied from 20 to 80% among the populations. Larvae reared on Cry1Ab maize had seven-day delay in development time in relation to control larvae, and such delay was shorter in offspring of armyworms from Cry1Ab maize. Population growth rates were 50-70% lower for insects continuously exposed to Cry1Ab maize relative to controls, showing the population-level effect of Cry1Ab, which varied among the populations and prior exposure to Cry1Ab maize in the field. In three out of five populations, armyworms derived from Bt maize reared on Cry1Ab maize showed higher larval weight, faster larval development and better reproductive performance than the armyworms derived from non-Bt maize, and one of these populations showed better performance on both Cry1Ab and control diets, indicating no fitness cost of the resistance trait. Altogether, these results indicate that offspring of armyworms that developed on field-grown, single-gene Bt Cry1Ab maize had reduced performance on Cry1Ab maize foliage in two populations studied, but in other three populations, these offspring had better overall performance on the Bt maize foliage than that of the armyworms from non-Bt maize fields, possibly because of Cry1Ab resistance alleles in

  1. Cross-generational feeding of Bt (Bacillus thuringiensis)-maize to zebrafish (Danio rerio) showed no adverse effects on the parental or offspring generations.

    Science.gov (United States)

    Sanden, Monica; Ornsrud, Robin; Sissener, Nini H; Jorgensen, Susanne; Gu, Jinni; Bakke, Anne Marie; Hemre, Gro-Ingunn

    2013-12-01

    In the present study, zebrafish (Danio rerio) were fed casein/gelatin-based diets containing either 19% Bt (Bacillus thuringiensis)-maize or its parental non-Bt (nBt)-maize control for two generations (F0: sixty fish; F1: forty-two to seventy fish per treatment). The study focused on growth and reproductive performance, liver CuZn superoxide dismutase (SOD) enzyme activity, gene transcript levels targeting important cellular pathways in the liver and mid-intestine, histomorphological evaluation of the intestine, differential leucocyte counts, offspring larva swimming activity and global DNA methylation in offspring embryos. No significant effects were observed in the parental generation. The offspring were either fed the same diets as those fed to their parents (Bt-Bt or nBt-nBt) or switched from the Bt diet to the nBt diet (Bt-nBt). The Bt-Bt offspring exhibited a significantly higher body mass increase, specific growth rate and feed utilisation than fish fed the nBt-nBt diet and/or fish fed the Bt-nBt diet. Liver and mid-intestinal gene transcript levels of CuZn SOD were significantly higher in fish fed the nBt-nBt diet than in those fed the Bt-Bt diet. Liver gene transcript levels of caspase 6 were significantly lower for the nBt-nBt group than for the Bt-Bt group. Overall, enhanced growth performance was observed in fish fed the Bt diet for two generations than in those fed the nBt diet for one and two generations. Effects observed on gene biomarkers for oxidative stress and the cell cycle (apoptosis) may be related to the contamination of nBt-maize with fumonisin B1 and aflatoxin B1. In conclusion, it is suggested that Bt-maize is as safe and nutritious as its nBt control when fed to zebrafish for two generations.

  2. Shock treatment of corn stover.

    Science.gov (United States)

    Bond, Austin; Rughoonundun, Hema; Petersen, Eric; Holtzapple, Carol; Holtzapple, Mark

    2017-05-01

    Corn stover digestibility was enhanced via shock treatment. A slurry of lime-treated corn stover was placed in a partially filled closed vessel. From the ullage space, either a shotgun shell was fired into the slurry, or a gas mixture was detonated. Various conditions were tested (i.e., pressures, depth, solids concentrations, gas mixtures). A high pressurization rate (108,000 MPa/s shotgun shells; 4,160,000 MPa/s hydrogen/oxygen detonation) was the only parameter that improved enzymatic digestibility. Stoichiometric propane/air deflagration had a low pressurization rate (37.2 MPa/s) and did not enhance enzymatic digestibility. Without shock, enzymatic conversion of lime-treated corn stover was 0.80 g glucan digested/g glucan fed with an enzyme loading of 46.7 mg protein/g glucan. With shock, the enzyme loading was reduced by ∼2× while maintaining the same conversion. Detonations are extraordinarily fast; rapidly cycling three small vessels (0.575 m 3 each) every 7.5 s enables commercially relevant shock treatment (2,000 tone/day). © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:815-823, 2017. © 2017 American Institute of Chemical Engineers.

  3. Assessment of the nutritional values of genetically modified wheat, corn, and tomato crops.

    Science.gov (United States)

    Venneria, Eugenia; Fanasca, Simone; Monastra, Giovanni; Finotti, Enrico; Ambra, Roberto; Azzini, Elena; Durazzo, Alessandra; Foddai, Maria Stella; Maiani, Giuseppe

    2008-10-08

    The genetic modification in fruit and vegetables could lead to changes in metabolic pathways and, therefore, to the variation of the molecular pattern, with particular attention to antioxidant compounds not well-described in the literature. The aim of the present study was to compare the quality composition of transgenic wheat ( Triticum durum L.), corn ( Zea mays L.), and tomato ( Lycopersicum esculentum Mill.) to the nontransgenic control with a similar genetic background. In the first experiment, Ofanto wheat cultivar containing the tobacco rab1 gene and nontransgenic Ofanto were used. The second experiment compared two transgenic lines of corn containing Bacillus thuringiensis "Cry toxin" gene (PR33P67 and Pegaso Bt) to their nontransgenic forms. The third experiment was conducted on transgenic tomato ( Lycopersicum esculentum Mill.) containing the Agrobacterium rhizogenes rolD gene and its nontransgenic control (cv. Tondino). Conventional and genetically modified crops were compared in terms of fatty acids content, unsaponifiable fraction of antioxidants, total phenols, polyphenols, carotenoids, vitamin C, total antioxidant activity, and mineral composition. No significant differences were observed for qualitative traits analyzed in wheat and corn samples. In tomato samples, the total antioxidant activity (TAA), measured by FRAP assay, and the naringenin content showed a lower value in genetically modified organism (GMO) samples (0.35 mmol of Fe (2+) 100 g (-1) and 2.82 mg 100 g (-1), respectively), in comparison to its nontransgenic control (0.41 mmol of Fe (2+) 100 g (-1) and 4.17 mg 100 g (-1), respectively). On the basis of the principle of substantial equivalence, as articulated by the World Health Organization, the Organization for Economic Cooperation and Development, and the United Nations Food and Agriculture Organization, these data support the conclusion that GM events are nutritionally similar to conventional varieties of wheat, corn, and tomato on

  4. Direct transcriptional activation of BT genes by NLP transcription factors is a key component of the nitrate response in Arabidopsis.

    Science.gov (United States)

    Sato, Takeo; Maekawa, Shugo; Konishi, Mineko; Yoshioka, Nozomi; Sasaki, Yuki; Maeda, Haruna; Ishida, Tetsuya; Kato, Yuki; Yamaguchi, Junji; Yanagisawa, Shuichi

    2017-01-29

    Nitrate modulates growth and development, functioning as a nutrient signal in plants. Although many changes in physiological processes in response to nitrate have been well characterized as nitrate responses, the molecular mechanisms underlying the nitrate response are not yet fully understood. Here, we show that NLP transcription factors, which are key regulators of the nitrate response, directly activate the nitrate-inducible expression of BT1 and BT2 encoding putative scaffold proteins with a plant-specific domain structure in Arabidopsis. Interestingly, the 35S promoter-driven expression of BT2 partially rescued growth inhibition caused by reductions in NLP activity in Arabidopsis. Furthermore, simultaneous disruption of BT1 and BT2 affected nitrate-dependent lateral root development. These results suggest that direct activation of BT1 and BT2 by NLP transcriptional activators is a key component of the molecular mechanism underlying the nitrate response in Arabidopsis. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. High-conversion hydrolysates and corn sweetener production in dry-grind corn process.

    Science.gov (United States)

    Most corn is processed to fuel ethanol and distillers’ grain animal feed using the dry grind process. However, wet milling is needed to refine corn starch. Corn starch is in turn processed to numerous products, including glucose and syrup. However, wet milling is a capital, labor, and energy intensi...

  6. Molecular and biochemical analysis of the plastidic ADP-glucose transporter (ZmBT1) from Zea mays.

    Science.gov (United States)

    Kirchberger, Simon; Leroch, Michaela; Huynen, Martijn A; Wahl, Markus; Neuhaus, H Ekkehard; Tjaden, Joachim

    2007-08-03

    Physiological studies on the Brittle1 maize mutant have provided circumstantial evidence that ZmBT1 (Zea mays Brittle1 protein) is involved in the ADP-Glc transport into maize endosperm plastids, but up to now, no direct ADP-Glc transport mediated by ZmBT1 has ever been shown. The heterologous synthesis of ZmBT1 in Escherichia coli cells leads to the functional integration of ZmBT1 into the bacterial cytoplasmic membrane. ZmBT1 transports ADP-Glc in counterexchange with ADP with apparent affinities of about 850 and 465 mum, respectively. Recently, a complete ferredoxin/thioredoxin system has been identified in cereal amyloplasts and BT1 has been proposed as a potential Trx target protein (Balmer, Y., Vensel, W. H., Cai, N., Manieri, W., Schurmann, P., Hurkman, W. J., and Buchanan, B. B. (2006) Proc. Natl. Acad. Sci. U. S. A. 103, 2988-2993). Interestingly, we revealed that the transport activity of ZmBT1 is reversibly regulated by redox reagents such as diamide and dithiothreitol. The expression of ZmBT1 is restricted to endosperm tissues during starch synthesis, whereas a recently identified BT1 maize homologue, the ZmBT1-2, exhibits a ubiquitous expression pattern in hetero- and autotrophic tissues indicating different physiological roles for both maize BT1 isoforms. BT1 homologues are present in both mono- and dicotyledonous plants. Phylogenetic analyses classify the BT1 family into two phylogenetically and biochemically distinct groups. The first group comprises BT1 orthologues restricted to cereals where they mediate the ADP-Glc transport into cereal endosperm storage plastids during starch synthesis. The second group occurs in mono- and dicotyledonous plants and is most probably involved in the export of adenine nucleotides synthesized inside plastids.

  7. Stakeholders' Beliefs about the "TOEFL iBT"® Test as a Measure of Academic Language Ability. "TOEFL iBT"® Research Report. TOEFL iBT-22. ETS Research Report. RR-14-42

    Science.gov (United States)

    Malone, Margaret E.; Montee, Megan

    2014-01-01

    The "TOEFL iBT"® test presents test takers with tasks meant to simulate the tasks required of students in English-medium universities. Research establishing the validity argument for the test provides evidence for score interpretation and the use of the test for university admissions and placement. Now that the test has been operational…

  8. Test Takers' Writing Activities during the "TOEFL iBT"® Writing Tasks: A Stimulated Recall Study. "TOEFL iBT"® Research Report. TOEFL iBT-25. ETS Research Report No. RR-15-04

    Science.gov (United States)

    Barkaoui, Khaled

    2015-01-01

    This study aimed to describe the writing activities that test takers engage in when responding to the writing tasks in the "TOEFL iBT"[superscript R] test and to examine the effects of task type and test-taker English language proficiency (ELP) and keyboarding skills on the frequency and distribution of these activities. Each of 22 test…

  9. The Effects of Different Levels of Performance Feedback on "TOEFL iBT"® Reading Practice Test Performance. TOEFL iBT Research Report. TOEFL iBT-29. ETS Research Report. RR-17-31

    Science.gov (United States)

    Sawaki, Yasuyo

    2017-01-01

    The purpose of the present study is to examine whether performance on the "TOEFL iBT"® Reading practice test is affected by 3 different levels of feedback provided to learners upon completion of reading exercises: (a) correctness of learner response (the knowledge of correct results [KCR] feedback), (b) KCR feedback and rationales for…

  10. Impact of Bt crops on non-target organisms – 3 systematic reviews

    Science.gov (United States)

    The cultivation of genetically modified (GM) crops producing Cry toxins, originating from the bacterium Bacillus thuringiensis (Bt), has raised environmental concerns over their sustainable use and consequences for biodiversity and ecosystem services in agricultural land. During the last two decades...

  11. Isolation of a novel uric-acid-degrading microbe Comamonas sp. BT ...

    Indian Academy of Sciences (India)

    2014-10-20

    Wallrath and Friedman. 1991; Yamamoto et al. 1996; Montalbini et al. ..... utilis uricase, recombinant, expressed in Escherichia coli;. Sigma EC 1.7.3.3) to compare performances. The sensitivity of BT UA uricase was much higher, ...

  12. Natural refuge crops, buildup of resistance, and zero-refuge strategy for Bt cotton in China.

    Science.gov (United States)

    Qiao, FangBin; Huang, JiKun; Rozelle, Scott; Wilen, James

    2010-10-01

    In the context of genetically modified crops expressing the Bacillus thuringiensis (Bt) toxin, a 'refuge' refers to a crop of the same or a related species that is planted nearby to enable growth and reproduction of the target pest without the selection pressure imposed by the Bt toxin. The goal of this study is to discuss the role of natural refuge crops in slowing down the buildup of resistance of cotton bollworm (CBW), and to evaluate China's no-refuge policy for Bt cotton. We describe in detail the different factors that China should consider in relation to the refuge policy. Drawing on a review of scientific data, economic analyses of other cases, and a simulation exercise using a bio-economic model, we show that in the case of Bt cotton in China, the no-refuge policy is defensible.

  13. Bt crop effects on functional guilds of non-target arthropods: A meta-analysis (journal)

    Science.gov (United States)

    Background: Uncertainty persists over the environmental effects of genetically-engineered crops that produce the insecticidal Cry proteins of Bacillus thuringiensis (Bt). We performed meta-analyses on a modified public database to synthesize current knowledge about the effects of...

  14. Synergistic action of enzyme preparations towards recalcitrant corn silage polysaccharides

    NARCIS (Netherlands)

    Neumüller, K.G.; Streekstra, H.; Schols, H.A.; Gruppen, H.

    2014-01-01

    Corn silage, its water unextractable solids (WUS) and enzyme recalcitrant solids (ErCS) and an industrial corn silage-based anaerobic fermentation residue (AFR) represent corn substrates with different levels of recalcitrance. Compositional analysis reveals different levels of arabinoxylan

  15. Adoption of Bt Cotton: Threats and Challenges Adopción de Algodón Bt: Desafíos y Amenazas

    Directory of Open Access Journals (Sweden)

    Muhammad Faisal Bilal

    2012-09-01

    Full Text Available Adopting new technology always involves advantages and risks; Bt cotton (Gossypium hirsutum L. is a new technology well known in developed countries for its many advantages, such as reduced pesticide application, better insect pest control, and higher lint yield. However, its success in developing countries is still a question mark. Global adoption of Bt cotton has risen dramatically from 0.76 million ha when introduced in 1996 to 7.85 million ha in the 2005 cotton-growing season where 54% of the cotton crops in the USA, 76% in China, and 80% in Australia were grown with single or multiple Bt genes. Bollworms are serious cotton pests causing 30-40% yield reduction in Pakistan and 20-66% potential crop losses in India. The major advances shown in this review include: (1 Evolution of Bt cotton may prove to be a green revolution to enhance cotton yield; (2 adoption of Bt cotton by farmers is increasing due to its beneficial environmental effects by reducing pesticide application: however, a high seed price has compelled farmers to use illegal non-approved Bt causing huge damage to crops because of low tolerance to insect pests; and (3 some factors responsible for changes in the efficiency of the Bt gene and Bt cotton yield include internal phenology (genetics, atmospheric changes (CO2 concentration, nutrition, insect pests, boll distribution pattern, disease and nematodes, removal of fruiting branch and/or floral bud, introduction of Bt gene, and terpenoids and tannin production in the plant body.La adopción de nueva tecnología siempre involucra ventajas y riesgos; algodón Bt (Gossypium hirsutum L. es una nueva tecnología bien conocida en países desarrollados por muchas ventajas como reducida aplicación de pesticidas, mejor control de insectos plaga, y mayor producción de fibra, pero su éxito en países en desarrollo aún conlleva dudas. La adopción global de algodón Bt ha aumentado dramáticamente de 0,76 millones de hectáreas en su

  16. The effect of feeding Bt MON810 maize to pigs for 110 days on intestinal microbiota.

    Directory of Open Access Journals (Sweden)

    Stefan G Buzoianu

    Full Text Available OBJECTIVE: To assess the effects of feeding Bt MON810 maize to pigs for 110 days on the intestinal microbiota. METHODOLOGY/PRINCIPAL FINDINGS: Forty male pigs (∼40 days old were blocked by weight and litter ancestry and assigned to one of four treatments; 1 Isogenic maize-based diet for 110 days (Isogenic; 2 Bt maize-based diet (MON810 for 110 days (Bt; 3 Isogenic maize-based diet for 30 days followed by a Bt maize-based diet for 80 days (Isogenic/Bt; 4 Bt maize-based diet for 30 days followed by an isogenic maize-based diet for 80 days (Bt/Isogenic. Enterobacteriaceae, Lactobacillus and total anaerobes were enumerated in the feces using culture-based methods on days 0, 30, 60 and 100 of the study and in ileal and cecal digesta on day 110. No differences were found between treatments for any of these counts at any time point. The relative abundance of cecal bacteria was also determined using high-throughput 16 S rRNA gene sequencing. No differences were observed in any bacterial taxa between treatments, with the exception of the genus Holdemania which was more abundant in the cecum of pigs fed the isogenic/Bt treatment compared to pigs fed the Bt treatment (0.012 vs 0.003%; P≤0.05. CONCLUSIONS/SIGNIFICANCE: Feeding pigs a Bt maize-based diet for 110 days did not affect counts of any of the culturable bacteria enumerated in the feces, ileum or cecum. Neither did it influence the composition of the cecal microbiota, with the exception of a minor increase in the genus Holdemania. As the role of Holdemania in the intestine is still under investigation and no health abnormalities were observed, this change is not likely to be of clinical significance. These results indicate that feeding Bt maize to pigs in the context of its influence on the porcine intestinal microbiota is safe.

  17. Determining the major Bt refuge crops for cotton bollworm in North China.

    Science.gov (United States)

    Ye, Le-Fu; Fu, Xue; Ouyang, Fang; Xie, Bao-Yu; Ge, Feng

    2015-12-01

    Evaluation of the effectiveness of refuge strategies involved in cotton bollworm Bt resistance management would be aided by technologies that allow monitoring and quantification of key factors that affect the process under field conditions. We hypothesized that characterization of stable carbon and nitrogen isotopes in adult bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) moths may aid in determining the larval host that they developed upon. We found moths reared from larvae fed on peanut, soybean or cotton, respectively, could be differentiated using isotopic analyses that also corresponded to their respective larval host origins. These techniques were then used to classify feral second-generation bollworm moths caught in Bt cotton (Gossypium hirsutum) fields into different populations based on their isotopic signatures. In 2006-2007 feral moths captured in Bt cotton fields predominantly correlated with the peanut (Arachis hypogea) having served as their larval host, indicating this is the most important refuge crop for Bt-susceptible bollworm individuals (providing 58%-64% individuals) during independent moth peaks for the second generation in North China. The remaining feral moths correlated with soybean (Glycine max) (0-10%); other C3 plant (20%-22%) and non-C3 plant (12%-14%) host types also provided some Bt-sensitive moths. Field observations showed that peanut constitutes the primary refuge crop contributing to sustaining Bt-susceptible moths dispersing into cotton in North China. These results suggest that peanut may be a more effective refuge to sustain Bt-susceptible bollworm individuals and reduce the risk of development of a Bt-resistant biotype. © 2014 Institute of Zoology, Chinese Academy of Sciences.

  18. Digestibility of amino acids in corn, corn coproducts, and bakery meal fed to growing pigs.

    Science.gov (United States)

    Almeida, F N; Petersen, G I; Stein, H H

    2011-12-01

    The objectives of this experiment were to determine the apparent ileal digestibility and the standardized ileal digestibility (SID) of CP and AA in bakery meal, corn gluten meal, corn gluten feed, corn germ meal, and hominy feed and to compare these values with the apparent ileal digestibility and SID of CP and AA in corn and distillers dried grains with solubles (DDGS). Eight growing barrows (initial BW: 82.5 ± 5.5 kg) were randomly allotted to an 8 × 8 Latin square design with 8 diets and 8 periods. Diets contained corn, DDGS, bakery meal, corn gluten meal, corn gluten feed, corn germ meal, or hominy feed as the sole source of protein and AA. An N-free diet was used to measure basal endogenous losses of AA and protein. Pigs were fed experimental diets for eight 7-d periods, with ileal digesta being collected on d 6 and 7 of each period. Results indicated that the SID of Lys in corn gluten meal (78.7%) was greater (P bakery meal, corn germ meal, and hominy feed (46.0, 48.4, 68.4, and 58.8%, respectively). The SID of all indispensable AA except Arg, Leu, and Met in bakery meal were not different from those in DDGS. The SID of Arg, His, Leu, and Met in corn gluten feed were less (P bakery meal had SID values of most AA that were less than in corn, but corn gluten meal had SID values for most AA that were greater than the SID of AA in corn, bakery meal, and corn coproducts.

  19. Benefits of Bt cotton counterbalanced by secondary pests? Perceptions of ecological change in China.

    Science.gov (United States)

    Zhao, Jennifer H; Ho, Peter; Azadi, Hossein

    2011-02-01

    In the past, scientific research has predicted a decrease in the effectiveness of Bt cotton due to the rise of secondary and other sucking pests. It is suspected that once the primary pest is brought under control, secondary pests have a chance to emerge due to the lower pesticide applications in Bt cotton cultivars. Studies on this phenomenon are scarce. This article furnishes empirical evidence that farmers in China perceive a substantial increase in secondary pests after the introduction of Bt cotton. The research is based on a survey of 1,000 randomly selected farm households in five provinces in China. We found that the reduction in pesticide use in Bt cotton cultivars is significantly lower than that reported in research elsewhere. This is consistent with the hypothesis suggested by recent studies that more pesticide sprayings are needed over time to control emerging secondary pests, such as aphids, spider mites, and lygus bugs. Apart from farmers' perceptions of secondary pests, we also assessed their basic knowledge of Bt cotton and their perceptions of Bt cotton in terms of its strengths and shortcomings (e.g., effectiveness, productivity, price, and pesticide use) in comparison with non-transgenic cotton.

  20. An Empirical Assessment of Transgene Flow from a Bt Transgenic Poplar Plantation.

    Directory of Open Access Journals (Sweden)

    Jianjun Hu

    Full Text Available To assess the possible impact of transgenic poplar plantations on the ecosystem, we analyzed the frequency and distance of gene flow from a mature male transgenic Populus nigra plantation carrying the Bacillus thuringiensis toxin gene (Bt poplar and the survival of Bt poplar seeds. The resultant Bt poplar seeds occurred at a frequency of ~0.15% at 0 m to ~0.02% at 500 m from the Bt poplar plantation. The germination of Bt poplar seeds diminished within three weeks in the field (germination rate from 68% to 0% compared to 48% after three weeks of storage at 4°C. The survival rate of seedlings in the field was 0% without any treatment but increased to 1.7% under the addition of four treatments (cleaning and trimming, watering, weeding, and covering with plastic film to maintain moisture after being seeded in the field for eight weeks. The results of this study indicate that gene flow originating from the Bt poplar plantation occurred at an extremely low level through pollen or seeds under natural conditions. This study provides first-hand field data on the extent of transgene flow in poplar plantations and offers guidance for the risk assessment of transgenic poplar plantations.

  1. Sustained susceptibility of pink bollworm to Bt cotton in the United States.

    Science.gov (United States)

    Tabashnik, Bruce E; Morin, Shai; Unnithan, Gopalan C; Yelich, Alex J; Ellers-Kirk, Christa; Harpold, Virginia S; Sisterson, Mark S; Ellsworth, Peter C; Dennehy, Timothy J; Antilla, Larry; Liesner, Leighton; Whitlow, Mike; Staten, Robert T; Fabrick, Jeffrey A; Li, Xianchun; Carrière, Yves

    2012-01-01

    Evolution of resistance by pests can reduce the benefits of transgenic crops that produce toxins from Bacillus thuringiensis (Bt) for insect control. One of the world's most important cotton pests, pink bollworm (Pectinophora gossypiella), has been targeted for control by transgenic cotton producing Bt toxin Cry1Ac in several countries for more than a decade. In China, the frequency of resistance to Cry1Ac has increased, but control failures have not been reported. In western India, pink bollworm resistance to Cry1Ac has caused widespread control failures of Bt cotton. By contrast, in the state of Arizona in the southwestern United States, monitoring data from bioassays and DNA screening demonstrate sustained susceptibility to Cry1Ac for 16 y. From 1996-2005, the main factors that delayed resistance in Arizona appear to be abundant refuges of non-Bt cotton, recessive inheritance of resistance, fitness costs associated with resistance and incomplete resistance. From 2006-2011, refuge abundance was greatly reduced in Arizona, while mass releases of sterile pink bollworm moths were made to delay resistance as part of a multi-tactic eradication program. Sustained susceptibility of pink bollworm to Bt cotton in Arizona has provided a cornerstone for the pink bollworm eradication program and for integrated pest management in cotton. Reduced insecticide use against pink bollworm and other cotton pests has yielded economic benefits for growers, as well as broad environmental and health benefits. We encourage increased efforts to combine Bt crops with other tactics in integrated pest management programs.

  2. Discrimination of corn from monocotyledonous weeds with ultraviolet (UV) induced fluorescence.

    Science.gov (United States)

    Panneton, Bernard; Guillaume, Serge; Samson, Guy; Roger, Jean-Michel

    2011-01-01

    In production agriculture, savings in herbicides can be achieved if weeds can be discriminated from crop, allowing the targeting of weed control to weed-infested areas only. Previous studies demonstrated the potential of ultraviolet (UV) induced fluorescence to discriminate corn from weeds and recently, robust models have been obtained for the discrimination between monocots (including corn) and dicots. Here, we developed a new approach to achieve robust discrimination of monocot weeds from corn. To this end, four corn hybrids (Elite 60T05, Monsanto DKC 26-78, Pioneer 39Y85 (RR), and Syngenta N2555 (Bt, LL)) and four monocot weeds (Digitaria ischaemum (Schreb.) I, Echinochloa crus-galli (L.) Beauv., Panicum capillare (L.), and Setaria glauca (L.) Beauv.) were grown either in a greenhouse or in a growth cabinet and UV (327 nm) induced fluorescence spectra (400 to 755 nm) were measured under controlled or uncontrolled ambient light intensity and temperature. This resulted in three contrasting data sets suitable for testing the robustness of discrimination models. In the blue-green region (400 to 550 nm), the shape of the spectra did not contain any useful information for discrimination. Therefore, the integral of the blue-green region (415 to 455 nm) was used as a normalizing factor for the red fluorescence intensity (670 to 755 nm). The shape of the normalized red fluorescence spectra did not contribute to the discrimination and in the end, only the integral of the normalized red fluorescence intensity was left as a single discriminant variable. Applying a threshold on this variable minimizing the classification error resulted in calibration errors ranging from 14.2% to 15.8%, but this threshold varied largely between data sets. Therefore, to achieve robustness, a model calibration scheme was developed based on the collection of a calibration data set from 75 corn plants. From this set, a new threshold can be estimated as the 85% quantile on the cumulative frequency

  3. Variation among conventional cultivars could be used as a criterion for environmental safety assessment of Bt rice on nontarget arthropods

    Science.gov (United States)

    Wang, Fang; Dang, Cong; Chang, Xuefei; Tian, Junce; Lu, Zengbin; Chen, Yang; Ye, Gongyin

    2017-02-01

    The current difficulty facing risk evaluations of Bacillus thuringiensis (Bt) crops on nontarget arthropods (NTAs) is the lack of criteria for determining what represents unacceptable risk. In this study, we investigated the biological parameters in the laboratory and field population abundance of Nilaparvata lugens (Hemiptera: Delphacidae) on two Bt rice lines and the non-Bt parent, together with 14 other conventional rice cultivars. Significant difference were found in nymphal duration and fecundity of N. lugens fed on Bt rice KMD2, as well as field population density on 12 October, compared with non-Bt parent. However, compared with the variation among conventional rice cultivars, the variation of each parameter between Bt rice and the non-Bt parent was much smaller, which can be easily seen from low-high bar graphs and also the coefficient of variation value (C.V). The variation among conventional cultivars is proposed to be used as a criterion for the safety assessment of Bt rice on NTAs, particularly when statistically significant differences in several parameters are found between Bt rice and its non-Bt parent. Coefficient of variation is suggested as a promising parameter for ecological risk judgement of IRGM rice on NTAs.

  4. Bt cotton producing Cry1Ac and Cry2Ab does not harm two parasitoids, Cotesia marginiventris and Copidosoma floridanum.

    Science.gov (United States)

    Tian, Jun-Ce; Wang, Xiang-Ping; Chen, Yang; Romeis, Jörg; Naranjo, Steven E; Hellmich, Richard L; Wang, Ping; Shelton, Anthony M

    2018-01-10

    Cabbage looper, Trichoplusia ni (Hübner) is an important lepidopteran pest on many vegetable and greenhouse crops, and some field crops. Although there are no commercial transgenic Bt vegetable or greenhouse crops, T. ni is a target of Bollgard II cotton, which produces Cry1Ac and Cry2Ab. We expand on previous work that examined the effect of Bt crops on parasitoids using Bt-resistant lepidopteran populations as hosts. Cry1Ac/Cry2Ab-resistant T. ni larvae were used to eliminate host quality effects and to evaluate the direct effects of Bt cotton on the parasitoids Copidosoma floridanum (Ashmead) and Cotesia marginiventris (Cresson). These tri-trophic studies confirm that Bt cotton had no significant impact on development, success of parasitism, survival and adult longevity of C. marginiventris when using Bt-resistant T. ni fed on Bt cotton. Similarly, this Bt cotton had no significant impact on the development, mummy weight and the number of progeny produced by C. floridanum. Our studies verified that lyophilized Bt crop tissue maintained its insecticidal bioactivity when incorporated into an artificial diet, demonstrating that hosts and parasitoids were exposed to active Cry proteins. The egg-larval parasitoid C. floridanum, or similar species that consume their entire host, should be considered useful surrogates in risk assessment of Bt crops to non-target arthropods.

  5. Magnitude differences in agronomic, chemical, nutritional, and structural features among different varieties of forage corn grown on dry land and irrigated land.

    Science.gov (United States)

    Xin, Hangshu; Abeysekara, Samen; Zhang, Xuewei; Yu, Peiqiang

    2015-03-11

    In this study, eight varieties of corn forage grown in semiarid western Canada (including Pioneer P2501, Pioneer P39m26, Pioneer P7443, Hyland HL3085, Hyland HLBaxxos, Hyland HLR219, Hyland HLSR22, and Pickseed Silex BT) were selected to explore the effect of irrigation implementation in comparison with nonirrigation on (1) agronomic characteristics, (2) basic chemical profiles explored by using a near-infrared reflectance (NIR) system, and (3) protein and carbohydrate internal structural parameters revealed by using an attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) system. Also, principal component analysis (PCA) was performed on spectroscopic data for clarification of differences in molecular structural makeup among the varieties. The results showed that irrigation treatment significantly increased (P corn forages. Significant interactions of irrigation treatment and corn variety were observed on most agronomic characteristics (DM yield, T/ha, days to tasseling, days to silking) and crude fiber (CF) and ether extract (EE) contents as well as some spectral data such as cellulosic compounds (CELC) peak intensity, peak ratios of CHO third peak to CELC, α-helix to β-sheet, and CHO third peak to amide I. Additionally, the spectral ratios of chemical functional groups that related to structural and nonstructural carbohydrates and protein polymers in forages did not remain constant over corn varieties cultivated with and without water treatment. Moreover, different cultivars had different growth, structure, and nutrition performances in this study. Although significant differences could be found in peak intensities, PCA results indicated some structural similarities existed between two treated corn forages with the exception of HL3085 and HLBaxxos. In conclusion, irrigation and corn variety had interaction effects on agronomic, chemical, nutritional, and structural features. Further study on the optimum level of irrigation for corn

  6. Cornelis den Hartog: an outstanding aquatic ecologist

    NARCIS (Netherlands)

    Velde, van der G.; Brock, T.C.M.; Kempers, A.J.

    1996-01-01

    A survey is given of the work and life of Cornelis den Hartog up to the date in 1996 on which he retired from his position as a professor at the University of Nijmegen. Cornelis (Kees) den Hartog made important contributions to aquatic ecology in the widest sense, e.G. On brackish water typology,

  7. Climate forecasts for corn producer decision making

    Science.gov (United States)

    Corn is the most widely grown crop in the Americas, with annual production in the United States of approximately 332 million metric tons. Improved climate forecasts, together with climate-related decision tools for corn producers based on these improved forecasts, could substantially reduce uncertai...

  8. Phosphorus digestibility and concentration of digestible and metabolizable energy in corn, corn coproducts, and bakery meal fed to growing pigs.

    Science.gov (United States)

    Rojas, O J; Liu, Y; Stein, H H

    2013-11-01

    Two experiments were conducted to determine the standardized total tract digestibility (STTD) of P and the concentration of DE and ME in corn, hominy feed, bakery meal, distillers dried grains with solubles (DDGS), corn gluten meal, corn gluten feed, and corn germ meal fed to growing pigs. In Exp. 1, 84 barrows (initial BW: 13.7±2.3 kg) were placed in metabolism cages and allotted to 14 diets with 6 replicate pigs per diet in a randomized complete block design. Seven diets were formulated to contain corn, hominy feed, bakery meal, DDGS, corn gluten meal, corn gluten feed, or corn germ meal as the sole source of P. Seven additional diets were similar to the initial 7 diets with the exception that 600 units of microbial phytase was included in each diet. The STTD of P was greater (Pbakery meal, and corn germ meal, and the STTD of P was also greater (Pbakery meal than in corn and hominy feed. Addition of phytase increased (Pbakery meal, and corn germ meal but not in corn gluten meal, corn gluten feed, or DDGS. In Exp. 2, 56 barrows (initial BW: 14.6±2.2 kg) were placed in metabolism cages and allotted to 7 diets with 8 replicate pigs per diet in a randomized complete block design. A corn-based diet consisting of 97.5% corn and vitamins and minerals was formulated. Four additional diets were formulated by mixing corn and DDGS, corn gluten feed, corn gluten meal, or corn germ meal, and 2 diets were based on hominy feed or bakery meal. The concentration of ME was 3,891, 3,675, 3,655, 3,694, 4,400, 3,169, and 3,150 kcal/kg DM in corn, hominy feed, bakery meal, DDGS, corn gluten meal, corn gluten feed, and corn germ meal, respectively. The ME (DM basis) in corn was greater (Pbakery meal, corn gluten feed, and corn germ meal, but less (Pbakery meal, and DDGS was greater (Pbakery meal, and corn germ meal, but phytase can be included in diets containing corn, hominy feed, bakery meal, and corn germ meal to improve P digestibility. The ME in corn gluten meal is greater than

  9. Does Content Knowledge Affect TOEFL iBT[TM] Reading Performance? A Confirmatory Approach to Differential Item Functioning. TOEFL iBT Research Report. RR-09-29

    Science.gov (United States)

    Liu, Ou Lydia; Schedl, Mary; Malloy, Jeanne; Kong, Nan

    2009-01-01

    The TOEFL iBT[TM] has increased the length of the reading passages in the reading section compared to the passages on the TOEFL[R] computer-based test (CBT) to better approximate academic reading in North American universities, resulting in a reduced number of passages in the reading test. A concern arising from this change is whether the decrease…

  10. Event-specific plasmid standards and real-time PCR methods for transgenic Bt11, Bt176, and GA21 maize and transgenic GT73 canola.

    Science.gov (United States)

    Taverniers, Isabel; Windels, Pieter; Vaïtilingom, Marc; Milcamps, Anne; Van Bockstaele, Erik; Van den Eede, Guy; De Loose, Marc

    2005-04-20

    Since the 18th of April 2004, two new regulations, EC/1829/2003 on genetically modified food and feed products and EC/1830/2003 on traceability and labeling of GMOs, are in force in the EU. This new, comprehensive regulatory framework emphasizes the need of an adequate tracing system. Unique identifiers, such as the transgene genome junction region or a specific rearrangement within the transgene DNA, should form the basis of such a tracing system. In this study, we describe the development of event-specific tracing systems for transgenic maize lines Bt11, Bt176, and GA21 and for canola event GT73. Molecular characterization of the transgene loci enabled us to clone an event-specific sequence into a plasmid vector, to be used as a marker, and to develop line-specific primers. Primer specificity was tested through qualitative PCRs and dissociation curve analysis in SYBR Green I real-time PCRs. The primers were then combined with event-specific TaqMan probes in quantitative real-time PCRs. Calibration curves were set up both with genomic DNA samples and the newly synthesized plasmid DNA markers. It is shown that cloned plasmid GMO target sequences are perfectly suitable as unique identifiers and quantitative calibrators. Together with an event-specific primer pair and a highly specific TaqMan probe, the plasmid markers form crucial components of a unique and straighforward tracing system for Bt11, Bt176, and GA21 maize and GT73 canola events.

  11. Bistand til risikovurdering Supplerende oplysninger fra Syngenta Seeds om overvågningsplanen (evt. ændret risikovurdering). Zea mays (Bt11). Supplerende materiale om Bt11

    DEFF Research Database (Denmark)

    Kjellsson, Gøsta; Strandberg, Morten Tune; Damgaard, Christian

    2005-01-01

    "Mail: Den supplerende information om Bt-11 majsen (C/F/96/05-10) der er modtaget d. 02-03-2005, indeholder en ny udgave af den generelle overvågningsplan med enkelte ændringer (forbedringer) i forhold til forrige udgave (kommenteret 24-02-2005). Vi har ikke fundet nogen nye oplysninger der ændrer...

  12. Bacillus thuringiensis (Bt) transgenic crop: an environment friendly insect-pest management strategy.

    Science.gov (United States)

    Kumar, Suresh; Chandra, Amaresh; Pandey, K C

    2008-09-01

    Introduction of DDT (dichloro-diphenyl-trichloroethane) and following move towards indiscriminate use of synthetic chemical insecticides led to the contamination of water and food sources, poisoning of non-target beneficial insects and development of insect-pests resistant to the chemical insecticides. Increased public concems about the adverse environmental effects of indiscriminate use of chemical insecticides prompted search of altemative methods for insect-pest control. One of the promising alternatives has been the use of biological control agents. There is well-documented history of safe application of Bt (B. thuringiensis, a gram positive soil bacterium) as effective biopesticides and a number of reports of expression of delta-endotoxin gene(s) in crop plants are available. Only a few insecticidal sprays are required on Bt transgenic crops, which not only save cost and time, but also reduce health risks. Insects exhibit remarkable ability to develop resistance to different insecticidal compounds, which raises concern about the unsystematic use of Bt transgenic technology also. Though resistance to Bt products among insect species under field conditions has been rare, laboratory studies show that insects are capable of developing high levels of resistance to one ormore Cry proteins. Now it is generally agreed that 'high-dose/refuge strategy' is the most promising and practical approach to prolong the effectiveness of Bt toxins. Although manybiosafety concerns, ethical and moral issues exist, area under Bt transgenic crops is rapidly increasing and they are cultivated on more than 32 million hectares world over Even after reservation of European Union (EU) for acceptance of geneticaly modified (GM) crops, 6 out of 25 countries have already adopted Bt crops and many otherindustrial countries will adopt Bt transgenic crops in near future. While the modem biotechnology has been recognized to have a great potential for the promotion of human well-being, adoption

  13. Expressed sequence tags from larval gut of the European corn borer (Ostrinia nubilalis: Exploring candidate genes potentially involved in Bacillus thuringiensis toxicity and resistance

    Directory of Open Access Journals (Sweden)

    Crespo Andre LB

    2009-06-01

    Full Text Available Abstract Background Lepidoptera represents more than 160,000 insect species which include some of the most devastating pests of crops, forests, and stored products. However, the genomic information on lepidopteran insects is very limited. Only a few studies have focused on developing expressed sequence tag (EST libraries from the guts of lepidopteran larvae. Knowledge of the genes that are expressed in the insect gut are crucial for understanding basic physiology of food digestion, their interactions with Bacillus thuringiensis (Bt toxins, and for discovering new targets for novel toxins for use in pest management. This study analyzed the ESTs generated from the larval gut of the European corn borer (ECB, Ostrinia nubilalis, one of the most destructive pests of corn in North America and the western world. Our goals were to establish an ECB larval gut-specific EST database as a genomic resource for future research and to explore candidate genes potentially involved in insect-Bt interactions and Bt resistance in ECB. Results We constructed two cDNA libraries from the guts of the fifth-instar larvae of ECB and sequenced a total of 15,000 ESTs from these libraries. A total of 12,519 ESTs (83.4% appeared to be high quality with an average length of 656 bp. These ESTs represented 2,895 unique sequences, including 1,738 singletons and 1,157 contigs. Among the unique sequences, 62.7% encoded putative proteins that shared significant sequence similarities (E-value ≤ 10-3with the sequences available in GenBank. Our EST analysis revealed 52 candidate genes that potentially have roles in Bt toxicity and resistance. These genes encode 18 trypsin-like proteases, 18 chymotrypsin-like proteases, 13 aminopeptidases, 2 alkaline phosphatases and 1 cadherin-like protein. Comparisons of expression profiles of 41 selected candidate genes between Cry1Ab-susceptible and resistant strains of ECB by RT-PCR showed apparently decreased expressions in 2 trypsin-like and 2

  14. Soil microflora and enzyme activities in rhizosphere of Transgenic Bt cotton hybrid under different intercropping systems and plant protection schedules

    Science.gov (United States)

    Biradar, D. P.; Alagawadi, A. R.; Basavanneppa, M. A.; Udikeri, S. S.

    2012-04-01

    Field experiments were conducted over three rainy seasons of 2005-06 to 2007-08 on a Vertisol at Dharwad, Karnataka, India to study the effect of intercropping and plant protection schedules on productivity, soil microflora and enzyme activities in the rhizosphere of transgenic Bt cotton hybrid. The experiment consisted of four intercropping systems namely, Bt cotton + okra, Bt cotton + chilli, Bt cotton + onion + chilli and Bt cotton + redgram with four plant protection schedules (zero protection, protection for Bt cotton, protection for intercrop and protection for both crops). Observations on microbial populations and enzyme activities were recorded at 45, 90, 135 and 185 (at harvest) days after sowing (DAS). Averaged over years, Bt cotton + okra intercropping had significantly higher total productivity than Bt cotton + chilli and Bt cotton + redgram intercropping system and was similar to Bt cotton + chilli + onion intercropping system. With respect to plant protection schedules for bollworms, protection for both cotton and intercrops recorded significantly higher yield than the rest of the treatments. Population of total bacteria, fungi, actinomycetes, P-solubilizers, free-living N2 fixers as well as urease, phosphatase and dehydrogenase enzyme activities increased up to 135 days of crop growth followed by a decline. Among the intercropping systems, Bt cotton + chilli recorded significantly higher population of microorganisms and enzyme activities than other cropping systems. While Bt cotton with okra as intercrop recorded the least population of total bacteria and free-living N2 fixers as well as urease activity. Intercropping with redgram resulted in the least population of actinomycetes, fungi and P-solubilizers, whereas Bt cotton with chilli and onion recorded least activities of dehydrogenase and phosphatase. Among the plant protection schedules, zero protection recorded maximum population of microorganisms and enzyme activities. This was followed by the

  15. Cry1F resistance in fall armyworm Spodoptera frugiperda: single gene versus pyramided Bt maize.

    Directory of Open Access Journals (Sweden)

    Fangneng Huang

    Full Text Available Evolution of insect resistance to transgenic crops containing Bacillus thuringiensis (Bt genes is a serious threat to the sustainability of this technology. However, field resistance related to the reduced efficacy of Bt maize has not been documented in any lepidopteran pest in the mainland U.S. after 18 years of intensive Bt maize planting. Here we report compelling evidence of field resistance in the fall armyworm, Spodoptera frugiperda (J.E. Smith, to Cry1F maize (TC 3507 in the southeastern region of the U.S. An F2 screen showed a surprisingly high (0.293 Cry1F resistance allele frequency in a population collected in 2011 from non-Bt maize in south Florida. Field populations from non-Bt maize in 2012-2013 exhibited 18.8-fold to >85.4-fold resistance to purified Cry1F protein and those collected from unexpectedly damaged Bt maize plants at several locations in Florida and North Carolina had >85.4-fold resistance. In addition, reduced efficacy and control failure of Cry1F maize against natural populations of S. frugiperda were documented in field trials using Cry1F-based and pyramided Bt maize products in south Florida. The Cry1F-resistant S. frugiperda also showed a low level of cross-resistance to Cry1A.105 and related maize products, but not to Cry2Ab2 or Vip3A. The occurrence of Cry1F resistance in the U.S. mainland populations of S. frugiperda likely represents migration of insects from Puerto Rico, indicating the great challenges faced in achieving effective resistance management for long-distance migratory pests like S. frugiperda.

  16. Cry1F resistance in fall armyworm Spodoptera frugiperda: single gene versus pyramided Bt maize.

    Science.gov (United States)

    Huang, Fangneng; Qureshi, Jawwad A; Meagher, Robert L; Reisig, Dominic D; Head, Graham P; Andow, David A; Ni, Xinzi; Kerns, David; Buntin, G David; Niu, Ying; Yang, Fei; Dangal, Vikash

    2014-01-01

    Evolution of insect resistance to transgenic crops containing Bacillus thuringiensis (Bt) genes is a serious threat to the sustainability of this technology. However, field resistance related to the reduced efficacy of Bt maize has not been documented in any lepidopteran pest in the mainland U.S. after 18 years of intensive Bt maize planting. Here we report compelling evidence of field resistance in the fall armyworm, Spodoptera frugiperda (J.E. Smith), to Cry1F maize (TC 3507) in the southeastern region of the U.S. An F2 screen showed a surprisingly high (0.293) Cry1F resistance allele frequency in a population collected in 2011 from non-Bt maize in south Florida. Field populations from non-Bt maize in 2012-2013 exhibited 18.8-fold to >85.4-fold resistance to purified Cry1F protein and those collected from unexpectedly damaged Bt maize plants at several locations in Florida and North Carolina had >85.4-fold resistance. In addition, reduced efficacy and control failure of Cry1F maize against natural populations of S. frugiperda were documented in field trials using Cry1F-based and pyramided Bt maize products in south Florida. The Cry1F-resistant S. frugiperda also showed a low level of cross-resistance to Cry1A.105 and related maize products, but not to Cry2Ab2 or Vip3A. The occurrence of Cry1F resistance in the U.S. mainland populations of S. frugiperda likely represents migration of insects from Puerto Rico, indicating the great challenges faced in achieving effective resistance management for long-distance migratory pests like S. frugiperda.

  17. Nutrient addition to corn masa flour: effect on corn flour stability, nutrient loss, and acceptability of fortified corn tortillas.

    Science.gov (United States)

    Rosado, Jorge L; Cassís, Lorena; Solano, Lourdes; Duarte-Vázquez, Miguel A

    2005-09-01

    Iron, zinc, and vitamin B complex are among the most prevalent nutritional deficiencies in Mexico, with iron deficiency being the leading cause of anemia. Mexico has the highest per capita consumption of corn in the world, consumed mainly as tortilla. Thus, corn flour for making tortillas has been suggested as an effective strategy to overcome malnutrition in developing countries such as Mexico where corn is a staple food. The stability of micronutrients added to food is an important factor for the success of fortification programs. The aim of this study was to evaluate the stability of corn flour fortified with micronutrients, and to measure the effect of micronutrient fortification on the sensory quality and stability of the fortificants in fresh and stored tortilla. A commercially homogenized nonfortified corn flour (NCFC) produced from degermed white corn was fortified with a premix containing iron, zinc, thiamin, and riboflavin. Changes in thiamin, riboflavin, iron, and zinc content in fortified corn flour (FCF) and nonfortified corn flour (NFCF) during storage were investigated. Vitamin B1 and B2 content was determined by fluorescence spectroscopy while iron and zinc content was analyzed by atomic absorption. Thiamin content in FCF and NFCF showed a significant (p flour into tortillas. Storage time slightly affected the stability of riboflavin and thiamin in FCF while the cooking process produced considerable losses of both vitamins. Tortillas made from FCF were well accepted by Mexican adults. We conclude that the addition of vitamins and minerals in the forms and quantities used in this study do not modify the shelf-life of corn flour, and neither do they cause sensorial changes in tortillas made from FCF.

  18. Localized search cues in corn roots for western corn rootworm (Coleoptera: Chrysomelidae) larvae.

    Science.gov (United States)

    Bernklau, E J; Bjostad, L B; Meihls, L N; Coudron, T A; Lim, E; Hibbard, B E

    2009-04-01

    Cues that elicit a characteristic localized search behavior by neonate larvae of the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), were extracted from living corn, Zea mays L., roots with acetone. Larvae were exposed to corn roots or to an acetone extract of corn roots and then transferred into a bioassay arena where their movements were tracked and recorded. After a 5-min exposure to live corn roots, larvae produced highly convoluted tracks that were indicative of a localized search behavior, and these distinctive tracks were also produced by larvae exposed to an acetone extract of corn roots. Larvae exposed to a filter paper control moved in relatively straight paths that were indicative of ranging behavior. Larval tracks were recorded by means of a videocamera and tracking software, and four parameters of movement were used to quantify the tracks: mean turn angle, mean meander, total distance, and maximum distance from origin. For every parameter measured, tracks resulting from exposure to the control were significantly different from tracks resulting from exposure to live corn roots and to all doses of the corn root extract. In a separate experiment, larvae exposed to corn root pieces or corn root juice exhibited the localized search behavior, but larvae exposed to oat root pieces and oat root juice (nonhost) exhibited ranging behavior.

  19. Insecticide enhancement with feeding stimulants in corn for western corn rootworm larvae (Coleoptera: Chrysomelidae).

    Science.gov (United States)

    Bernklau, E J; Bjostad, L B

    2005-08-01

    Amounts of the insecticide thiamethoxam required for 50% mortality of western corn rootworm larvae, Diabrotica virgifera virgifera LeConte, were reduced 100-fold when extracts of germinating corn, Zea mays L., were used to entice neonate larvae to feed on it. In behavioral bioassays, neonate rootworm larvae fed vigorously on filter paper disks treated with liquid pressed from corn roots. Moreover, disks treated with an acetone extract of corn (dried and rewetted with water) also elicited strong feeding from larvae. Larvae wandered away from filter paper disks treated with distilled water without feeding. Dilutions of thiamethoxam were tested in the bioassay alone or with corn extract and the efficacy of this insecticide was improved by the addition of the corn extract. For solutions containing 10 ppm thiamethoxam, 95% larval mortality occurred after 30 min of exposure when corn extract was present, but only 38% mortality occurred when the same concentration of insecticide alone (no feeding stimulants) was tested. Larval mortality after 24 h was significantly higher for corn extract-treated disks with 0.01, 0.1, 1, or 10 ppm insecticide than for the same concentrations without corn extract. Thiamethoxam did not deter larval feeding on corn extract, even at the highest concentration of thiamethoxam tested.

  20. Production of thermotolerant entomopathogenic Isaria fumosorosea SFP-198 conidia in corn-corn oil mixture.

    Science.gov (United States)

    Kim, Jae Su; Je, Yeon Ho; Roh, Jong Yul

    2010-04-01

    Low thermotolerance of entomopathogenic fungi is a major impediment to long-term storage and effective application of these biopesticides under seasonal high temperatures. The effects of high temperatures on the viability of an entomopathogenic fungus, Isaria fumosorosea SFP-198 (KCTC 0499BP), produced on different substrates amended with various additives were explored. Ground corn was found to be superior in producing the most thermotolerant conidia compared to yellow soybean, red kidney bean, and rice in a polyethylene bag production system. Using ground corn mixed with corn oil as a substrate resulted in only 7% reduction in germination compared to ground corn alone (67% reduction) after exposure of conidia to 50 degrees C for 2 h. Corn oil as an additive for ground corn was followed by inorganic salts (KCl and NaCl), carbohydrates (sucrose and dextrin), a sugar alcohol (sorbitol), and plant oils (soybean oil and cotton seed oil) in ability to improve conidial thermotolerance. Unsaturated fatty acids, such as linoleic acid and oleic acid, the main components of corn oil, served as effective additives for conidial thermotolerance in a dosage-dependent manner, possibly explaining the improvement by corn oil. This finding suggests that the corn-corn oil mixture can be used to produce highly thermotolerant SFP-198 conidia and provides the relation of unsaturated fatty acids as substrates with conidial thermotolerance.

  1. Test Review: Test of English as a Foreign Language[TM]--Internet-Based Test (TOEFL iBT[R])

    Science.gov (United States)

    Alderson, J. Charles

    2009-01-01

    In this article, the author reviews the TOEFL iBT which is the latest version of the TOEFL, whose history stretches back to 1961. The TOEFL iBT was introduced in the USA, Canada, France, Germany and Italy in late 2005. Currently the TOEFL test is offered in two testing formats: (1) Internet-based testing (iBT); and (2) paper-based testing (PBT).…

  2. Target and nontarget effects of novel "triple-stacked" Bt-transgenic cotton 1: canopy arthropod communities.

    Science.gov (United States)

    Whitehouse, M E A; Wilson, L J; Davies, A P; Cross, D; Goldsmith, P; Thompson, A; Harden, S; Baker, G

    2014-02-01

    Transgenic cotton varieties (Bollgard II) expressing two proteins (Cry1Ac and Cry2Ab) from Bacillus thuringiensis (Bt) have been widely adopted in Australia to control larvae of Helicoverpa. A triple-stacked Bt-transgenic cotton producing Cry1Ac, Cry2Ab, and Vip3A proteins (Genuity Bollgard III) is being developed to reduce the chance that Helicoverpa will develop resistance to the Bt proteins. Before its introduction, nontarget effects on the agro-ecosystem need to be evaluated under field conditions. By using beatsheet and suction sampling methods, we compared the invertebrate communities of unsprayed non-Bt-cotton, Bollgard II, and Bollgard III in five experiments across three sites in Australia. We found significant differences between invertebrate communities of non-Bt and Bt (Bollgard II and Bollgard III) cotton only in experiments where lepidopteran larval abundance was high. In beatsheet samples where lepidopterans were absent (Bt crops), organisms associated with flowers and bolls in Bt-cotton were more abundant. In suction samples, where Lepidoptera were present (i.e., in non-Bt-cotton), organisms associated with damaged plant tissue and frass were more common. Hence in our study, Bt- and non-Bt-cotton communities only differed when sufficient lepidopteran larvae were present to exert both direct and indirect effects on species assemblages. There was no overall significant difference between Bollgard II and III communities, despite the addition of the Vip gene in Bollgard III. Consequently, the use of Bollgard III in Australian cotton provides additional protection against the development of resistance by Helicoverpa to Bt toxins, while having no additional effect on cotton invertebrate communities.

  3. Multipass rotary shear comminution process to produce corn stover particles

    Science.gov (United States)

    Dooley, James H; Lanning, David N

    2015-04-14

    A process of comminution of corn stover having a grain direction to produce a mixture of corn stover, by feeding the corn stover in a direction of travel substantially randomly to the grain direction one or more times through a counter rotating pair of intermeshing arrays of cutting discs (D) arrayed axially perpendicular to the direction of corn stover travel.

  4. 21 CFR 137.285 - Degerminated yellow corn meal.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Degerminated yellow corn meal. 137.285 Section 137... Cereal Flours and Related Products § 137.285 Degerminated yellow corn meal. Degerminated yellow corn meal, degermed yellow corn meal, conforms to the definition and standard of identity prescribed by § 137.265 for...

  5. Possible causes of dry pea synergy to corn

    Science.gov (United States)

    Dry pea improves corn yield and tolerance to weed interference compared with soybean, spring wheat, or canola as preceding crops. To understand this synergy between dry pea and corn, we examined growth and nutrient concentration of corn following dry pea or soybean in sequence. Each corn plot was ...

  6. Intercropping of corn with cowpea and bean: Biomass yield and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-11-19

    Nov 19, 2008 ... quality of corn (Zea mays indendata) mixed with legumes such as various cowpea (Vigna ungiuculata) and bean (Phaseolus vulgaris) ... seeding of soybean with corn in alternate-rows as 1 corn + 1 soybean or 1 corn + 2 ..... And also silage quality is many times more significant property than quantity.

  7. Fitness cost of resistance to Bt cotton linked with increased gossypol content in pink bollworm larvae.

    Directory of Open Access Journals (Sweden)

    Jennifer L Williams

    Full Text Available Fitness costs of resistance to Bacillus thuringiensis (Bt crops occur in the absence of Bt toxins, when individuals with resistance alleles are less fit than individuals without resistance alleles. As costs of Bt resistance are common, refuges of non-Bt host plants can delay resistance not only by providing susceptible individuals to mate with resistant individuals, but also by selecting against resistance. Because costs typically vary across host plants, refuges with host plants that magnify costs or make them less recessive could enhance resistance management. Limited understanding of the physiological mechanisms causing fitness costs, however, hampers attempts to increase costs. In several major cotton pests including pink bollworm (Pectinophora gossypiella, resistance to Cry1Ac cotton is associated with mutations altering cadherin proteins that bind this toxin in susceptible larvae. Here we report that the concentration of gossypol, a cotton defensive chemical, was higher in pink bollworm larvae with cadherin resistance alleles than in larvae lacking such alleles. Adding gossypol to the larval diet decreased larval weight and survival, and increased the fitness cost affecting larval growth, but not survival. Across cadherin genotypes, the cost affecting larval growth increased as the gossypol concentration of larvae increased. These results suggest that increased accumulation of plant defensive chemicals may contribute to fitness costs associated with resistance to Bt toxins.

  8. Effect of irradiation on physiological and biochemical properties of Bt rice seedlings

    International Nuclear Information System (INIS)

    Wang Zhonghua; Chen Xiaojian; Bao Xusheng; Chen Yuling; Gu Qinqin

    2011-01-01

    The seeds of two varieties of Bt rice were treated by 60 Co γ-rays at the doses of 50, 100, 150, 250 and 350 Gy, respectively, their original parent was used as control material. The seedlings cultured from above seeds were used to detect the root activity, seedling growth, chlorophyll content,activities of phenylalanine ammonialyase (PAL), polyphenol oxidase (PPO), catalase(CAT), superoxide dismutase (SOD) and amylase to investigate the effect of irradiation treatment on the physiological and biochemical properties of Bt rice. The results showed that root activity, chlorophyll content, activities of PAL, PPO, CAT, SOD of Bt rice seedlings and amylase of germinating seeds were lower than those of the control group after irradiation treatment of < 250 Gy, but the differences were not significant, which was similar to those of original parent. Meanwhile, it was found that with dose increasing, the seedling height was increased, suggesting that irradiation treatment could stimulate the seedling growth. Therefore, Bt transgene can not change the irradiation sensitivity of rice and the conventional method of rice can be used in Bt rice irradiation mutation breeding. (authors)

  9. Dielectric properties of BNT-xBT prepared by hydrothermal process

    Directory of Open Access Journals (Sweden)

    Natheer B. Mahmood

    2017-06-01

    Full Text Available The BNT ceramic sample might be a good replacement for PZT piezoelectric in industrial applications, especially in energy harvesting from crystal vibrations. In order to enhance the performance of BNT ceramic, the solid solution was chosen by substitution with Ba+2 at Morphtropic Phase Boundary (MPB. The BNT-xBT powders with x=1, 0.07, 0.06 and 0 were prepared by the hydrothermal method with average particle size (65–150nm at (90∘C/72h. The ceramic disc was sintered at (1150∘C/4h and showed excellent relative density of about 96%. The results of X-ray diffraction (XRD confirmed the MPB for x=0.06 and 0.07, while the BNT had a rhombohedral structure and BT had a tetragonal structure. The dielectric measurements showed that BNT, BNT-7BT, BNT-6BT behave as the relaxator ferroelectric and showed a strong dependence on frequency, especially in the MPB region while BT behaves as a normal ferroelectric. Both the Curie temperature and depolarization temperature decrease at the MPB region and showed strong dependency on frequency.

  10. Larval Dispersal of Spodoptera frugiperda Strains on Bt Cotton: A Model for Understanding Resistance Evolution and Consequences for its Management

    OpenAIRE

    Malaquias, José B.; Godoy, Wesley A. C.; Garcia, Adriano G.; Ramalho, Francisco de S.; Omoto, Celso

    2017-01-01

    High dispersal of Lepidoptera larvae between non-Bt and Bt cotton plants can favour the evolution of insect resistance; however, information on host acceptance of neonates in tropical transgenic crops is scarce. Therefore, the purposes of this study were as follows: (i) to investigate the feeding behaviour of susceptible and Cry1F-resistant strains of Spodoptera frugiperda (J.E. Smith) on Bt and non-Bt cotton (Gossypium hirsutum L.) varieties and (ii) to understand the possible effects of cot...

  11. Spring harvest of corn stover

    Energy Technology Data Exchange (ETDEWEB)

    Lizotte, P.L. [Laval Univ., Quebec City, PQ (Canada). Dept. des sols et de genie agroalimentaire; Savoie, P. [Agriculture and Agri-Food Canada, Quebec City, PQ (Canada)

    2010-07-01

    Corn stover is typically left behind in the field after grain harvest. Although part of the stover should remain in the field for soil organic matter renewal and erosion protection, half of the stover could be removed sustainably. This represents about one million t dry matter (DM) of stover per year in the province of Quebec. Stover harvested in the fall is very wet. While there are applications for wet stover, the available markets currently require a dry product. Preliminary measurements have shown that stover left in the field throughout the winter becomes very dry, and a considerable amount would still be harvestable in the spring. In the spring of 2009, corn stover was harvested at 2 sites, each subdivided into 2 parcels. The first parcel was cut and raked in the fall of 2008 (fall parcel), while the second parcel was cut and raked in spring 2009. Fibre from both parcels was baled in the spring 2009. At the first site, a large square baler was used in late April to produce bales measuring 0.8 m x 0.9 m x 1.8 m. On the second site a round baler was used in late May to produce bales of 1.2 m in width by 1.45 m in diameter. On the second site, a small square baler was also used to produce bales of 0.35 m x 0.45 m x 0.60 m (spring cutting only). With the large square baler, an average of 3.9 t DM/ha was harvested equally on the fall parcel and the spring parcel, representing a 48 per cent recovery of biomass based on stover yields.

  12. Seasonality of Colaspis crinicornis (Coleoptera: Chrysomelidae) and its Injury Potential to Corn in Southeastern Nebraska.

    Science.gov (United States)

    Miwa, Kentaro; Meinke, Lance J

    2018-02-09

    Colaspis crinicornis Schaeffer (Coleoptera: Chrysomelidae) primarily occurs in the Great Plains, United States. Although C. crinicornis has historically been considered a non-pest and is rarely found in agricultural systems, population densities of this species have been increasing in corn, Zea mays L., and soybean, Glycine max (L.) Merrill, over the last decade in southeastern Nebraska. As part of a comprehensive project to understand the life history and pest potential of C. crinicornis, a field study was conducted to: understand adult seasonality of C. crinicornis using emergence cages and whole-plant-count sampling in cornfields and sweep-net sampling in soybean fields; confirm voltinism and the overwintering stage; and evaluate the potential of larvae to cause economic injury to corn roots. Data indicate that C. crinicornis is univoltine in southeastern Nebraska and overwinters as medium-large larvae at least 20 cm deep in the soil. Adults were present from June through August with peak emergence in July. The C. crinicornis lifecycle is similar to related Colaspis species. Root injury to corn was minor at population densities encountered in the field, and therefore, C. crinicornis is unlikely to cause economic loss. C. crinicornis may be an example of an insect species that has exploited open niches in crops that have been created by changes in agricultural and pest management practices. The lifecycle and polyphagous nature of the insect, annual crop rotation, the shift to minimum tillage, and replacement of insecticides with Bacillus thuringiensis Berliner (Bt) traits may have collectively facilitated establishment and increased survival in agroecosystems. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Genetic variability in populations of sweet corn, common corn and teosinte

    OpenAIRE

    Almeida,Cicero; Amorim,Edson Perito; Barbosa Neto,José Fernandes; Cardoso Filho,Julio Alves; Sereno,Maria Jane Cruz de Melo

    2011-01-01

    The maize (Zea mays L. ssp. mays) has several related species, called teosinte, which are distributed in various subspecies of Zea and other genera. Among the different types of corn, sweet corn shows a great potential for human food. This type was originated from mutations, which increased the amount of polysaccharide in the endosperm. In Brazil there are populations of sweet corn, common maize and teosinte, however, little is known about their genetic variability. Hence, the aim of this pre...

  14. Genetic variability in populations of sweet corn, common corn and teosinte.

    OpenAIRE

    Cicero Almeida; Edson Perito Amorim; José Fernandes Barbosa Neto; Julio Alves Cardoso Filho; Maria Jane Cruz de Melo Sereno

    2011-01-01

    The maize (Zea mays L. ssp. mays) has several related species, called teosinte, which are distributed in varioussubspecies of Zea and other genera. Among the different types of corn, sweet corn shows a great potential for human food. This typewas originated from mutations, which increased the amount of polysaccharide in the endosperm. In Brazil there are populations ofsweet corn, common maize and teosinte, however, little is known about their genetic variability. Hence, the aim of this presen...

  15. An economic evaluation of impact of soil quality on Bt (Bacillus thuringiensis cotton productivity

    Directory of Open Access Journals (Sweden)

    Muhammad Abid*, Muhammad Ashfaq, Imran Khalid and Usman Ishaq

    2011-04-01

    Full Text Available The study was conducted with the aim to determine the impact of soil quality on the Bt cotton productivity. Asample of 150 farmers was selected by using multi-stage sampling technique from three districts i.e. Rahim YarKhan, Multan and Mianwali. A Cobb Douglas production function was employed to assess the effect of variousagronomic and demographic variables on the Bt cotton productivity. Results of the analysis indicated that landpreparation cost, seed cost, fertilizer cost, labour cost and dummy variable of soil quality were significant andpositively contributing towards higher Bt cotton yield. While the spray cost and irrigation cost variable were foundpositive but non-significant. Findings of the study suggested that focusing on maintaining and improving the qualityof soils is necessary to obtain higher crop yields. All this needs attention of agricultural extension department toprovide information about advance techniques to farmers for improving soil quality.

  16. Plant Fitness Assessment for Wild Relatives of Insect Resistant Bt-Crops

    Directory of Open Access Journals (Sweden)

    D. K. Letourneau

    2012-01-01

    Full Text Available When field tests of transgenic plants are precluded by practical containment concerns, manipulative experiments can detect potential consequences of crop-wild gene flow. Using topical sprays of bacterial Bacillus thuringiensis larvicide (Bt and larval additions, we measured fitness effects of reduced herbivory on Brassica rapa (wild mustard and Raphanus sativus (wild radish. These species represent different life histories among the potential recipients of Bt transgenes from Bt cole crops in the US and Asia, for which rare spontaneous crosses are expected under high exposure. Protected wild radish and wild mustard seedlings had approximately half the herbivore damage of exposed plants and 55% lower seedling mortality, resulting in 27% greater reproductive success, 14-day longer life-spans, and 118% more seeds, on average. Seed addition experiments in microcosms and in situ indicated that wild radish was more likely to spread than wild mustard in coastal grasslands.

  17. Function and effectiveness of natural refuge in IRM strategies for Bt crops.

    Science.gov (United States)

    Li, Yunhe; Gao, Yulin; Wu, Kongming

    2017-06-01

    Several strategies involving refuge have been proposed for delaying insect resistance to Bt crops. The report was focused on the unstructured 'natural' refuges that contain plants naturally presented as part of the cropping system in the form of non-Bt plants that differ from Bt plant species, or wild host plants of the target pests. The cases of natural refuges applied in different countries were analyzed, and the factors that favor their success are discussed. The results indicate that the effectiveness of a natural refuge strategy depends on the biological characteristics of the target pest, the spatial and temporal distribution and abundance of the host plants in the agricultural system and the quality of the host plants for the pest species. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. SN 2006bt: A PERPLEXING, TROUBLESOME, AND POSSIBLY MISLEADING TYPE Ia SUPERNOVA

    International Nuclear Information System (INIS)

    Foley, Ryan J.; Narayan, Gautham; Challis, Peter J.; Kirshner, Robert P.; Filippenko, Alexei V.; Silverman, Jeffrey M.; Steele, Thea N.

    2010-01-01

    SN 2006bt displays characteristics unlike those of any other known Type Ia supernova (SN Ia). We present optical light curves and spectra of SN 2006bt which demonstrate the peculiar nature of this object. SN 2006bt has broad, slowly declining light curves indicative of a hot, high-luminosity SN, but lacks a prominent second maximum in the i band as do low-luminosity SNe Ia. Its spectra are similar to those of low-luminosity SNe Ia, containing features that are only present in cool SN photospheres. Light-curve fitting methods suggest that SN 2006bt is reddened by a significant amount of dust; however, it occurred in the outskirts of its early-type host galaxy and has no strong Na D absorption in any of its spectra, suggesting a negligible amount of host-galaxy dust absorption. C II is possibly detected in our pre-maximum spectra, but at a much lower velocity than other elements. The progenitor was likely very old, being a member of the halo population of a galaxy that shows no signs of recent star formation. SNe Ia have been very successfully modeled as a one-parameter family, and this is fundamental to their use as cosmological distance indicators. SN 2006bt is a challenge to that picture, yet its relatively normal light curves allowed SN 2006bt to be included in cosmological analyses. We generate mock SN Ia data sets which indicate that contamination by similar objects will both increase the scatter of a SN Ia Hubble diagram and systematically bias measurements of cosmological parameters. However, spectra and rest-frame i-band light curves should provide a definitive way to identify and eliminate such objects.

  19. Identification of relevant non-target organisms exposed to weevil-resistant Bt sweetpotato in Uganda.

    Science.gov (United States)

    Rukarwa, R J; Mukasa, S B; Odongo, B; Ssemakula, G; Ghislain, M

    2014-06-01

    Assessment of the impact of transgenic crops on non-target organisms (NTO) is a prerequisite to their release into the target environment for commercial use. Transgenic sweetpotato varieties expressing Cry proteins (Bt sweetpotato) are under development to provide effective protection against sweetpotato weevils (Coleoptera) which cause severe economic losses in sub-Saharan Africa. Like any other pest control technologies, genetically engineered crops expressing insecticidal proteins need to be evaluated to assess potential negative effects on non-target organisms that provide important services to the ecosystem. Beneficial arthropods in sweetpotato production systems can include pollinators, decomposers, and predators and parasitoids of the target insect pest(s). Non-target arthropod species commonly found in sweetpotato fields that are related taxonomically to the target pests were identified through expert consultation and literature review in Uganda where Bt sweetpotato is expected to be initially evaluated. Results indicate the presence of few relevant non-target Coleopterans that could be affected by Coleopteran Bt sweetpotato varieties: ground, rove and ladybird beetles. These insects are important predators in sweetpotato fields. Additionally, honeybee (hymenoptera) is the main pollinator of sweetpotato and used for honey production. Numerous studies have shown that honeybees are unaffected by the Cry proteins currently deployed which are homologous to those of the weevil-resistant Bt sweetpotato. However, because of their feeding behaviour, Bt sweetpotato represents an extremely low hazard due to negligible exposure. Hence, we conclude that there is good evidence from literature and expert opinion that relevant NTOs in sweetpotato fields are unlikely to be affected by the introduction of Bt sweetpotato in Uganda.

  20. Control of ferroelectric phase transition in nano particulate NBT–BT based ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Devi, Ch. Sameera; Kumar, G.S. [Department of Physics, Osmania University, Hyderabad 500 007 (India); Prasad, G., E-mail: gudurup@gmail.com [Department of Physics, Osmania University, Hyderabad 500 007 (India)

    2013-03-20

    Graphical abstract: Modified Curie–Weiss law fitting of BT1, NBT1, NBT2 and NBT3 samples and inset shows modified Curie–Weiss law fitting for NBT at 10 kHz frequency. Highlights: ► For the first time we have studied the effect of Nd{sup 3+} and BT on structural changes in NBT lattice. ► Ti metal powder was used instead of TiO{sub 2} to synthesize the ceramics using sol–gel. ► FTIR and Raman spectra were recorded for NBT–BT based ceramics. ► In dielectric measurements the transition from relaxor to normal with doping is observed. -- Abstract: Lead free relaxor NBT–BT based ceramic compositions were prepared using sol–gel method. The samples were sintered around 1140 °C for 3–4 h in the air. The characterization was done using X-ray diffraction (XRD), filed emission scanning electron microscope (FESEM), energy dispersive spectrometry (EDS), Raman, Fourier transform infrared (FTIR), dielectric and P–E loop measurements. The XRD patterns recorded at room temperature confirmed the phase formation of the samples. From FESEM micrographs, the particle sizes were estimated for calcined powders and are found to be in the range of 50–70 nm. The analysis of both Raman and FTIR spectral data of the samples also indicated the distortion of NBT lattice with the addition of Ba{sup 2+} and Nd{sup 3+} ions. It was found that the dielectric and piezoelectric properties of NBT–BT compositions beyond the morphotrophic phase boundary (MPB) are rather sensitive to the presence of tetragonal phase in addition to the rhombohedral phase. NBT ceramics exhibit a decrease in diffusive factor with increasing BT content, implying a degradation of relaxor feature leading to the normal ferroelectric nature. The ceramic samples employed in the present study exhibited variation in P–E hysteresis loops.

  1. Renewable corn-ethanol and energy security

    International Nuclear Information System (INIS)

    Eaves, James

    2007-01-01

    Though corn-ethanol is promoted as renewable, models of the production process assume fossil fuel inputs. Moreover, ethanol is promoted as a means of increasing energy security, but there is little discussion of the dependability of its supply. This study investigates the sensibility of promoting corn-ethanol as an automobile fuel, assuming a fully renewable production process. We then use historical data to estimate the supply risk of ethanol relative to imported petroleum. We find that devoting 100% of US corn to ethanol would displace 3.5% of gasoline consumption and the annual supply of the ethanol would be inherently more risky than that of imported oil. Finally, because large temperature increases can simultaneously increase fuel demand and the cost of growing corn, the supply responses of ethanol producers to temperature-induced demand shocks would likely be weaker than those of gasoline producers. (author)

  2. 21 CFR 184.1865 - Corn syrup.

    Science.gov (United States)

    2010-04-01

    ... “glucose syrup,” is obtained by partial hydrolysis of corn starch with safe and suitable acids or enzymes. It may also occur in the dehydrated form (dried glucose sirup). Depending on the degree of hydrolysis...

  3. Uptake and distribution of cadmium in corn

    International Nuclear Information System (INIS)

    Peel, J.W.; Vetter, R.J.; Christian, J.E.; Kessler, W.V.; McFee, W.W.

    1978-01-01

    The uptake and distribution of cadmium in corn (Zea mays) treated at various time intervals after planting and sampled at various times after treatment were measured. Cadmium was found to accumulate in all parts sampled. As shown in field studies, stems and leaves generally concentrated more cadmium than did husks, cobs, kernels, silks, or tassels. Samples of stems and leaves from corn treated 23 days after planting and sampled 5 days later exhibited higher concentrations of cadmium than samples taken 25, 45, 65, or 85 days after treatment. Concentrations generally decreased with time. Greenhouse studies showed that corn exposed to cadmium for the longest period of time accumulated the greatest total cadmium. The highest cadmium concentrations were found in the base or lowest leaves sampled 45 days after planting; this suggests a useful technique for quick screening corn crops for cadmium pollution

  4. Can Bt Technology Reduce Poverty Among African Cotton Growers? An Ex Ante Analysis of the Private and Social Profitability of Bt Cotton Seed in Mozambique.

    OpenAIRE

    Pitoro, Raul; Walker, Thomas S.; Tschirley, David L.; Swinton, Scott M.; Boughton, Duncan; de Marrule, Higino Francisco

    2009-01-01

    This paper presents an ex ante analysis of the private and social profitability of the introduction of Bt cotton for a major cotton producing area of northern Mozambique. Cotton is especially relevant to rural poverty reduction because smallholders often have few alternative cash earning activities, and yields are among the lowest in Africa. Multivariate regression is used to quantify the relationship between pest control and yield loss at farm level as a basis for estimating the expected yie...

  5. Initial mechanisms for the decomposition of electronically excited energetic materials: 1,5′-BT, 5,5′-BT, and AzTT

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Bing; Yu, Zijun; Bernstein, Elliot R., E-mail: erb@lamar.Colostate.edu [Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872 (United States)

    2015-03-28

    Decomposition of nitrogen-rich energetic materials 1,5′-BT, 5,5′-BT, and AzTT (1,5′-Bistetrazole, 5,5′-Bistetrazole, and 5-(5-azido-(1 or 4)H-1,2,4-triazol-3-yl)tetrazole, respectively), following electronic state excitation, is investigated both experimentally and theoretically. The N{sub 2} molecule is observed as an initial decomposition product from the three materials, subsequent to UV excitation, with a cold rotational temperature (<30 K). Initial decomposition mechanisms for these three electronically excited materials are explored at the complete active space self-consistent field (CASSCF) level. Potential energy surface calculations at the CASSCF(12,8)/6-31G(d) level illustrate that conical intersections play an essential role in the decomposition mechanism. Electronically excited S{sub 1} molecules can non-adiabatically relax to their ground electronic states through (S{sub 1}/S{sub 0}){sub CI} conical intersections. 1,5′-BT and 5,5′-BT materials have several (S{sub 1}/S{sub 0}){sub CI} conical intersections between S{sub 1} and S{sub 0} states, related to different tetrazole ring opening positions, all of which lead to N{sub 2} product formation. The N{sub 2} product for AzTT is formed primarily by N–N bond rupture of the –N{sub 3} group. The observed rotational energy distributions for the N{sub 2} products are consistent with the final structures of the respective transition states for each molecule on its S{sub 0} potential energy surface. The theoretically derived vibrational temperature of the N{sub 2} product is high, which is similar to that found for energetic salts and molecules studied previously.

  6. Decrease in catalase activity of Folsomia candida fed a Bt rice diet

    DEFF Research Database (Denmark)

    Yuan, Yiyang; Ke, Xin; Chen, Fajun

    2011-01-01

    Here we report the effects of three Bt-rice varieties and their non-Bt conventional isolines on biological traits including survival, reproduction, and the activities of three antioxidant enzymes superoxide dismutase, catalase and peroxidase, in the Collembolan, Folsomia candida. The reproduction...... was significantly lower when fed Kemingdao and Huahui1 than those feeding on their non-GM near-isogenic varieties Xiushui and Minghui63 respectively, this can be explained by the differences of plant compositions depended on variety of rice. The catalase activity of F. candida was significantly lower when fed...

  7. A New Developed GIHS-BT-SFIM Fusion Method Based On Edge and Class Data

    Directory of Open Access Journals (Sweden)

    S. Dehnavi

    2013-09-01

    Full Text Available The objective of image fusion (or sometimes pan sharpening is to produce a single image containing the best aspects of the source images. Some desirable aspects are high spatial resolution and high spectral resolution. With the development of space borne imaging sensors, a unified image fusion approach suitable for all employed imaging sources becomes necessary. Among various image fusion methods, intensity-hue-saturation (IHS and Brovey Transforms (BT can quickly merge huge amounts of imagery. However they often face color distortion problems with fused images. The SFIM fusion is one of the most frequently employed approaches in practice to control the tradeoff between the spatial and spectral information. In addition it preserves more spectral information but suffer more spatial information loss. Its effectiveness is heavily depends on the filter design. In this work, two modifications were tested to improve the spectral quality of the images and also investigating class-based fusion results. First, a Generalized Intensity-Hue-Saturation (GIHS, Brovey Transform (BT and smoothing-filter based intensity modulation (SFIM approach was implemented. This kind of algorithm has shown computational advantages among other fusion methods like wavelet, and can be extended to different number of bands as in literature discussed. The used IHS-BT-SFIM algorithm incorporates IHS, IHS-BT, BT, BT-SFIM and SFIM methods by two adjustable parameters. Second, a method was proposed to plus edge information in previous GIHS_BT_SFIM and edge enhancement by panchromatic image. Adding panchromatic data to images had no much improvement. Third, an edge adaptive GIHS_BT_SFIM was proposed to enforce fidelity away from the edges. Using MS image off edges has shown spectral improvement in some fusion methods. Fourth, a class based fusion was tested, which tests different coefficients for each method due to its class. The best parameters for vegetated areas was k1 = 0.6, k2

  8. Impact of efficient refuge policies for Bt cotton in India on world cotton trade

    OpenAIRE

    Singla, Rohit; Johnson, Phillip N.; Misra, Sukant K.

    2010-01-01

    India is a major cotton producing country in the world along with the U.S. and China. A change in the supply of and demand for cotton in the Indian market has the potential to have an impact on world cotton trade. This study evaluates the implications of efficient Bt cotton refuge policies in India on world and U.S. cotton markets. It can be hypothesized that increased refuge requirements for Bt cotton varieties in India could decrease the world supply of cotton because of the lower yield pot...

  9. Consequences for Protaphorura armata (Collembola: Onychiuridae) following exposure to genetically modified Bacillus thuringiensis (Bt) maize and non-Bt maize

    DEFF Research Database (Denmark)

    Heckmann, Lars-Henrik; Griffiths, Bryan S; Caul, Sandra

    2006-01-01

    armata. For comparison three non-Bt maize varieties, Rivaldo (isogenic to Cascade), Monumental (isogenic to MEB307) and DK242, and two control diets based on baker's yeast (uncontaminated and contaminated with Bt toxin Cry1Ab) were also tested. Due to a lower C:N ratio, individuals reared on yeast...

  10. Atrazine Metabolism in Resistant Corn and Sorghum

    Science.gov (United States)

    Shimabukuro, R. H.

    1968-01-01

    The metabolism of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) in the resistant species, corn (Zea mays L.) and sorghum (Sorghum vulgare Pers.) was not the same. In corn, atrazine was metabolized via both the 2-hydroxylation and N-dealkylation pathways while sorghum metabolized atrazine via the N-dealkylation pathway. Atrazine metabolism in corn yielded the metabolites, 2-hydroxy-4-ethylamino-6-isopropylamino-s-triazine (hydroxyatrazine), 2-hydroxy-4-amino-6-isopropylamino-s-triazine (hydroxycompound I), and 2-hydroxy-4-amino-6-ethylamino-s-triazine (hydroxycompound II). None of these hydroxylated derivatives appeared as metabolites of atrazine in sorghum. Hydroxycompounds I and II were formed in 2 ways in corn: (1) by benzoxazinone-catalyzed hydrolysis of 2-chloro-4-amino-6-isopropylamino-s-triazine (compound I) and 2-chloro-4-amino-6-ethylamino-s-triazine (compound II) that were formed by N-dealkylation of atrazine and (2) by N-dealkylation of hydroxyatrazine, the major atrazine metabolite in corn. The interaction of the 2-hydroxylation and N-dealkylation pathways in corn results in the formation of the 3 hydroxylated non-phytotoxic derivatives of atrazine. Images PMID:16656991

  11. Molecular and biochemical analysis of the plastidic ADP-glucose transporter (ZmBT1) from Zea mays.

    NARCIS (Netherlands)

    Kirchberger, S.; Leroch, M.; Huynen, M.A.; Wahl, M.; Neuhaus, H.E.; Tjaden, J.

    2007-01-01

    Physiological studies on the Brittle1 maize mutant have provided circumstantial evidence that ZmBT1 (Zea mays Brittle1 protein) is involved in the ADP-Glc transport into maize endosperm plastids, but up to now, no direct ADP-Glc transport mediated by ZmBT1 has ever been shown. The heterologous

  12. Molecular and biochemical analysis of the plastidic ADP-glucose transporter (ZmBT1) from Zea mays

    NARCIS (Netherlands)

    Kirchberger, S.; Leroch, M.; Huynen, M.A.; Wahl, M.; Neuhaus, H.E.; Tjaden, J.

    2007-01-01

    Physiological studies on the Brittle1 maize mutant have provided circumstantial evidence that ZmBT1 (Zea mays Brittle1 protein) is involved in the ADP-Glc transport into maize endosperm plastids, but up to now, no direct ADP-Glc transport mediated by ZmBT1 has ever been shown. The heterologous

  13. Delta's Key to the Next Generation TOEFL[R] Test: Essential Grammar for the iBT

    Science.gov (United States)

    Gallagher, Nancy

    2012-01-01

    Although the TOEFL iBT does not have a discrete grammar section, knowledge of English sentence structure is important throughout the test. Essential Grammar for the iBT reviews the skills that are fundamental to success on tests. Content includes noun and verb forms, clauses, agreement, parallel structure, punctuation, and much more. The book may…

  14. Transgenic Bt Cotton Does Not Disrupt the Top-Down Forces Regulating the Cotton Aphid in Central China.

    Directory of Open Access Journals (Sweden)

    Yong-Sheng Yao

    Full Text Available Top-down force is referred to arthropod pest management delivered by the organisms from higher trophic levels. In the context of prevalent adoption of transgenic Bt crops that produce insecticidal Cry proteins derived from Bacillus thuringiensis (Bt, it still remains elusive whether the top-down forces are affected by the insect-resistant traits that introduced into the Bt crops. We explored how Bt cotton affect the strength of top-down forces via arthropod natural enemies in regulating a non-target pest species, the cotton aphid Aphis gossypii Glover, using a comparative approach (i.e. Bt cotton vs. conventional cotton under field conditions. To determine top-down forces, we manipulated predation/parasitism exposure of the aphid to their natural enemies using exclusion cages. We found that the aphid population growth was strongly suppressed by the dominant natural enemies including Coccinellids, spiders and Aphidiines parasitoids. Coccinellids, spiders and the assemblage of other arthropod natural enemies (mainly lacewings and Hemipteran bugs are similarly abundant in both plots, but with the parasitoid mummies less abundant in Bt cotton plots compared to the conventional cotton plots. However, the lower abundance of parasitoids in Bt cotton plots alone did not translate into differential top-down control on A. gossypii populations compared to conventional ones. Overall, the top-down forces were equally strong in both plots. We conclude that transgenic Bt cotton does not disrupt the top-down forces regulating the cotton aphid in central China.

  15. Effect of Cry1Ab protein on rhizobacterial communities of Bt-maize over a four-year cultivation period.

    Directory of Open Access Journals (Sweden)

    Jorge Barriuso

    Full Text Available BACKGROUND: Bt-maize is a transgenic variety of maize expressing the Cry toxin from Bacillus turingiensis. The potential accumulation of the relative effect of the transgenic modification and the cry toxin on the rhizobacterial communities of Bt-maize has been monitored over a period of four years. METHODOLOGY/PRINCIPAL FINDINGS: The accumulative effects of the cultivation of this transgenic plant have been monitored by means of high throughput DNA pyrosequencing of the bacterial DNA coding for the 16S rRNA hypervariable V6 region from rhizobacterial communities. The obtained sequences were subjected to taxonomic, phylogenetic and taxonomic-independent diversity studies. The results obtained were consistent, indicating that variations detected in the rhizobacterial community structure were possibly due to climatic factors rather than to the presence of the Bt-gene. No variations were observed in the diversity estimates between non-Bt and Bt-maize. CONCLUSIONS/SIGNIFICANCE: The cultivation of Bt-maize during the four-year period did not change the maize rhizobacterial communities when compared to those of the non-Bt maize. This is the first study to be conducted with Bt-maize during such a long cultivation period and the first evaluation of rhizobacterial communities to be performed in this transgenic plant using Next Generation Sequencing.

  16. The end of a myth – Bt(Cry1Ab) maize does not harm green lacewings

    Science.gov (United States)

    A concern with Bt-transgenic insect-resistant plants is their potential to harm non-target organisms. Early studies reported that Cry1Ab-producing Bt maize and purified Cry1Ab harmed larvae of the green lacewing, Chrysoperla carnea. Although these effects could not be confirmed in subsequent studies...

  17. Characterizing indirect prey-quality mediated effects of a Bt crop on predatory larvae of the green lacewing, Chrysoperla carnea.

    Science.gov (United States)

    Lawo, Nora C; Wäckers, Felix L; Romeis, Jörg

    2010-11-01

    There is increasing evidence that insecticidal transgenic crops can indirectly cause detrimental effects on arthropod predators or parasitoids when they prey on or parasitize sublethally affected herbivores. Our studies revealed that Chrysoperla carnea is negatively affected when fed Bt-susceptible but not Cry1Ac-resistant Helicoverpa armigera larvae that had fed Bt-transgenic cotton expressing Cry1Ac. This despite the fact that the predators ingested 3.5 times more Cry1Ac when consuming the resistant caterpillars. In order to detect potential differences in the nutrient composition of prey larvae, we evaluated the glycogen and lipid content plus the sugar and free amino acid content and composition of caterpillars fed non-Bt and Bt cotton. The only change in susceptible H. armigera larvae attributable to Bt cotton feeding were changes in sugar concentration and composition. In case of the Cry1Ac-resistant H. armigera strain, feeding on Bt cotton resulted in a reduced glycogen content in the caterpillars. The predators, however, appeared to compensate for the reduced carbohydrate content of the prey by increasing biomass uptake which caused an excess intake of the other analyzed nutritional compounds. Our study clearly proves that nutritional prey-quality factors other then the Bt protein underlie the observed negative effects when C. carnea larvae are fed with Bt cotton-fed prey. Possible factors were an altered sugar composition or fitness costs associated with the excess intake of other nutrients. Copyright 2010 Elsevier Ltd. All rights reserved.

  18. Effects of transgenic Bt+CpTI cotton on the growth and reproduction of earthworm Eisenia foetida.

    Science.gov (United States)

    Liu, Biao; Cui, Jinjie; Meng, Jun; Hu, Wenjun; Luo, Junyu; Zheng, Yangping

    2009-01-01

    With the expansion of the planted area of transgenic Bt+CpTI cotton, the effects of this crop on non-target organisms in soil, including earthworms, are becoming the most important aspect of their ecological risk assessment. Laboratory toxicity studies were conducted to determine the effects of transgenic Bt+CpTI cotton leaves, containing high concentrations of the Bt toxin and cowpea trypsin inhibitor, on the earthworm Eisenia foetida. In comparison with the non-transgenic cotton line Zhong23, transgenic Bt+CpTI cotton Zhong41 had no significant acute toxicity on E. foetida. Moreover, the leaves of transgenic Bt+CpTI cotton were more suitable than the non-transgenic cotton Zhong23 for E. foetida growth and reproduction (time of reproduction, the number of cocoons and newly incubated offspring).

  19. 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.

  20. Managing the Risk of European Corn Borer Resistance to Transgenic Corn: An Assessment of Refuge Recommendations

    OpenAIRE

    Terrance M. Hurley; Silvia Secchi; Bruce A. Babcock

    1999-01-01

    The use of Genetically Modified Organisms (GMOs) in agriculture has been on the rise since 1995. Scientists have been working to develop a high-dose refuge management plan that can effectively delay European corn borer resistance to pesticidal GMO corn. This paper develops a stochastic agricultural production model to assess and provide insight into the reasons why refuge recommendations remain controversial.

  1. 21 CFR 184.1262 - Corn silk and corn silk extract.

    Science.gov (United States)

    2010-04-01

    .... Nonalcoholic beverages, § 170.3(n)(3) of this chapter 20 Do. Frozen dairy desserts, § 170.3(n)(20) of this... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Corn silk and corn silk extract. 184.1262 Section 184.1262 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  2. A Study of the Use of the "TOEFL iBT"® Test Speaking and Listening Scores for International Teaching Assistant Screening. "TOEFL iBT"® Research Report. TOEFL iBT-27. ETS Research Report. RR-16-18

    Science.gov (United States)

    Wagner, Elvis

    2016-01-01

    Although the speaking section of the "TOEFL iBT"® test is used by many universities to determine if international teaching assistants (ITAs) have the oral proficiency necessary to be classroom instructors, relatively few studies have investigated the validity of using TOEFL iBT scores for ITA screening. The primary purpose of this study…

  3. Investigating the Predictive Validity of "TOEFL iBT"® Test Scores and Their Use in Informing Policy in a United Kingdom University Setting. "TOEFL iBT"® Research Report. TOEFL iBT-30. ETS Research Report. RR-17-41

    Science.gov (United States)

    Harsch, Claudia; Ushloda, Ema; Ladroue, Christophe

    2017-01-01

    The project examined the predictive validity of the "TOEFL iBT"® test with a focus on the relationship between TOEFL iBT scores and students' subsequent academic success in postgraduate studies in one leading university in the United Kingdom, paying specific attention to the role of linguistic preparedness as perceived by students and…

  4. Surface chemistry of photoluminescent F8BT conjugated polymer nanoparticles determines protein corona formation and internalization by phagocytic cells.

    Science.gov (United States)

    Ahmad Khanbeigi, Raha; Abelha, Thais Fedatto; Woods, Arcadia; Rastoin, Olivia; Harvey, Richard D; Jones, Marie-Christine; Forbes, Ben; Green, Mark A; Collins, Helen; Dailey, Lea Ann

    2015-03-09

    Conjugated polymer nanoparticles are being developed for a variety of diagnostic and theranostic applications. The conjugated polymer, F8BT, a polyfluorene derivative, was used as a model system to examine the biological behavior of conjugated polymer nanoparticle formulations stabilized with ionic (sodium dodecyl sulfate; F8BT-SDS; ∼207 nm; -31 mV) and nonionic (pegylated 12-hydroxystearate; F8BT-PEG; ∼175 nm; -5 mV) surfactants, and compared with polystyrene nanoparticles of a similar size (PS200; ∼217 nm; -40 mV). F8BT nanoparticles were as hydrophobic as PS200 (hydrophobic interaction chromatography index value: 0.96) and showed evidence of protein corona formation after incubation with serum-containing medium; however, unlike polystyrene, F8BT nanoparticles did not enrich specific proteins onto the nanoparticle surface. J774A.1 macrophage cells internalized approximately ∼20% and ∼60% of the F8BT-SDS and PS200 delivered dose (calculated by the ISDD model) in serum-supplemented and serum-free conditions, respectively, while cell association of F8BT-PEG was minimal (<5% of the delivered dose). F8BT-PEG, however, was more cytotoxic (IC50 4.5 μg cm(-2)) than F8BT-SDS or PS200. The study results highlight that F8BT surface chemistry influences the composition of the protein corona, while the properties of the conjugated polymer nanoparticle surfactant stabilizer used determine particle internalization and biocompatibility profile.

  5. Improved Position and Additional Photometry for ASASSN-18bt, Bright Supernova in a Kepler Supernova Field

    Science.gov (United States)

    Cornect, R.; Brimacombe, J.; Stone, G.; Post, R. S.; Brown, J. S.; Stanek, K. Z.; Kochanek, C. S.; Vallely, P.; Shields, J.; Thompson, T. A.; Shappee, B. J.; Holoien, T. W.-S.; Prieto, J. L.; Bersier, D.; Dong, Subo; Bose, S.; Chen, Ping; Stritzinger, M.; Holmbo, S.; Bock, G.; Kiyota, S.

    2018-02-01

    We have obtained additional follow-up imaging, using several telescopes, of the nearby type Ia supernova ASASSN-18bt (ATEL #11253). This figure shows the archival SDSS g-band image of the host (left) and the R. Post confirmation image (right).

  6. Sixteen Years of Bt Maize in the EU Hotspot: Why Has Resistance Not Evolved?

    Science.gov (United States)

    Castañera, Pedro; Farinós, Gema P; Ortego, Félix; Andow, David A

    2016-01-01

    The majority of Bt maize production in the European Union (EU) is concentrated in northeast Spain, which is Europe's only hotspot where resistance might evolve, and the main target pest, Sesamia nonagrioides, has been exposed to Cry1Ab maize continuously since 1998. The cropping system in northeast Spain has some similar characteristics to those that probably led to rapid resistance failures in two other target noctuid maize pests. These include repeated cultivation of Bt maize in the same fields, low use of refuges, recurring exposure of larvae to non-high dose concentrations of Cry1Ab toxin during the first years of cultivation, low migratory potential, and production concentrated in an irrigated region with few alternative hosts. Available data reveal no evidence of resistance in S. nonagrioides after 16 years of use. We explore the possible reasons for this resistance management success using evolutionary models to consider factors expected to accelerate resistance, and those expected to delay resistance. Low initial adoption rates and the EU policy decision to replace Event 176 with MON 810 Bt maize were key to delaying resistance evolution. Model results suggest that if refuge compliance continues at the present 90%, Bt maize might be used sustainably in northeast Spain for at least 20 more years before resistance might occur. However, obtaining good estimates of the present R allele frequency and level of local assortative mating are crucial to reduce uncertainty about the future success of resistance management.

  7. 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.

  8. Stability of UV exposed RR-P3BT films by spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Diware, Mangesh S.; Byun, J. S.; Hwang, S. Y.; Kim, T. J.; Kim, Y. D.

    2013-01-01

    Stability of regioregular poly(3-butylthiophene) (RR-P3BT) films under irradiation of ultra-violet (UV) light has been studied by spectroscopic ellipsometry at room temperature. Consistent decrease in dielectric function with UV exposure time showed the degree of degradation of polymer. This work suggests that, protective methods are mandatory to use this kind of material in optical devices.

  9. Tritrophic choice experiments with Bt plants, the diamondback moth (Plutella xylostella) and the parasitoid Cotesia plutellae

    NARCIS (Netherlands)

    Schuler, T.H.; Potting, R.P.J.; Denholm, I.; Clark, S.J.; Clark, A.J.; Stewart, C.N.; Poppy, G.M.

    2003-01-01

    Parasitoids are important natural enemies of many pest species and are used extensively in biological and integrated control programmes. Crop plants transformed to express toxin genes derived from Bacillus thuringiensis (Bt) provide high levels of resistance to certain pest species, which is likely

  10. Stacked Bt maize and arthropod predators: exposure to insecticidal Cry proteins and potential hazards

    Czech Academy of Sciences Publication Activity Database

    Svobodová, Zdeňka; Shu, Y.; Skoková Habuštová, Oxana; Romeis, J.; Meissle, M.

    2017-01-01

    Roč. 284, č. 1859 (2017), č. článku 20170440. ISSN 0962-8452 Institutional support: RVO:60077344 Keywords : Bt maize * Cry proteins * environmental risk assessment Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection OBOR OECD: Agronomy, plant breeding and plant protection Impact factor: 4.940, year: 2016 http://rspb.royalsocietypublishing.org/content/284/1859/20170440

  11. Quantification of the histochemical reaction for alkaline phosphatase activity using the indoxyl-tetranitro BT method

    NARCIS (Netherlands)

    van Noorden, C. J.; Jonges, G. N.

    1987-01-01

    The indoxyl-tetranitro BT method for the demonstration of alkaline phosphatase activity has been optimized and its validity for quantitative histochemistry tested. The study has been performed with model films of polyacrylamide gel incorporating homogenate of rat liver and with cryostat sections

  12. Reduced fitness of Daphnia magna fed a Bt-transgenic maize variety.

    Science.gov (United States)

    Bøhn, Thomas; Primicerio, Raul; Hessen, Dag O; Traavik, Terje

    2008-11-01

    Genetically modified (GM) maize expressing the Bt-toxin Cry1Ab (Bt-maize) was tested for effects on survival, growth, and reproduction of the water flea Daphnia magna, a crustacean arthropod commonly used as a model organism in ecotoxicological studies. In three repeated experiments, D. magna were fed 100% ground maize in suspension, using either GM or isogenic unmodified (UM) maize. D. magna fed GM-maize showed a significantly reduced fitness performance: The mortality was higher, a lower proportion of females reached sexual maturation, and the overall egg production was lower compared to D. magna fed UM isogenic maize. We conclude that the tested variety of Bt-maize and its UM counterpart do not have the same quality as food sources for this widely used model organism. The combination of a reduced fitness performance combined with earlier onset of reproduction of D. magna fed Bt-maize indicates a toxic effect rather than a lower nutritional value of the GM-maize.

  13. FORMING OF MECHANICAL CHARACTERISTICS OF THE SLUGS OF TITANIC ALLOY BT23 AT THERMAL TREATMENT

    Directory of Open Access Journals (Sweden)

    V. N. Fedulov

    2005-01-01

    Full Text Available Тhе changings of the initial plate structure of alloy BT23 at running of high-temperature thermal treatment of large-sized slugs with heating up to 650- 950 eC and cooling on air and in water and their influence on forming of complex of mechanical characteristics are examined.

  14. TOEFL iBT Speaking Test Scores as Indicators of Oral Communicative Language Proficiency

    Science.gov (United States)

    Bridgeman, Brent; Powers, Donald; Stone, Elizabeth; Mollaun, Pamela

    2012-01-01

    Scores assigned by trained raters and by an automated scoring system (SpeechRater[TM]) on the speaking section of the TOEFL iBT[TM] were validated against a communicative competence criterion. Specifically, a sample of 555 undergraduate students listened to speech samples from 184 examinees who took the Test of English as a Foreign Language…

  15. Relationship of TOEFL iBT[R] Scores to Academic Performance: Some Evidence from American Universities

    Science.gov (United States)

    Cho, Yeonsuk; Bridgeman, Brent

    2012-01-01

    This study examined the relationship between scores on the TOEFL Internet-Based Test (TOEFL iBT[R]) and academic performance in higher education, defined here in terms of grade point average (GPA). The academic records for 2594 undergraduate and graduate students were collected from 10 universities in the United States. The data consisted of…

  16. Construct Validity in TOEFL iBT Speaking Tasks: Insights from Natural Language Processing

    Science.gov (United States)

    Kyle, Kristopher; Crossley, Scott A.; McNamara, Danielle S.

    2016-01-01

    This study explores the construct validity of speaking tasks included in the TOEFL iBT (e.g., integrated and independent speaking tasks). Specifically, advanced natural language processing (NLP) tools, MANOVA difference statistics, and discriminant function analyses (DFA) are used to assess the degree to which and in what ways responses to these…

  17. Validating TOEFL[R] iBT Speaking and Setting Score Requirements for ITA Screening

    Science.gov (United States)

    Xi, Xiaoming

    2007-01-01

    Although the primary use of the speaking section of the Test of English as a Foreign Language Internet-based test (TOEFL[R] iBT Speaking) is to inform admissions decisions at English medium universities, it may also be useful as an initial screening measure for international teaching assistants (ITAs). This study provides criterion-related…

  18. IMPACT OF BT ( BACILLUS THURINGIENSIS ) CROPS ON BAT ACTIVITY IN SOUTH TEXAS AGROECOSYSTEMS

    Science.gov (United States)

    The widespread adoption of transgenic insecticidal crops raises concerns that nontarget species may be harmed and food webs disrupted. The goal of this research is to determine how transgenic Bt (Bacillus thuringiensis) crops impact the activity of Brazilian freetailed bats (Tada...

  19. Isolation of a novel uric-acid-degrading microbe Comamonas sp. BT ...

    Indian Academy of Sciences (India)

    2014-10-20

    Oct 20, 2014 ... The strain was found to be produce extracellular uricase, and so it was very easy to extract from suspension culture. 3.3 Identification of strain. The strain BT UA was gram-negative, betaproteobacteria. Colonies on agar (NB-UA) plate were translucent and moist. The pigment of the colonies varied from ...

  20. screening of new isolates of bt and cloning of their dna amplicons

    African Journals Online (AJOL)

    NEMAPPA

    2012-09-18

    Sep 18, 2012 ... and biopesticides [Bacillus thuringiensis (Bt)] have proved beneficial over conventional chemical pesticides in controlling them. The cry toxins constitute a family of related proteins that can kill insects belonging to the. Lepidoptera, Coleoptera, Diptera, Hymenoptera, Homoptera, and Mallophaga, as well as ...

  1. Fitness costs associated with field-evolved resistance to Bt maize in Spodoptera frugiperda (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Jakka, S R K; Knight, V R; Jurat-Fuentes, J L

    2014-02-01

    Increasing adoption of transgenic crops expressing cry toxin genes from Bacillus thuringiensis (Bt crops) represents an augmented risk for development of insect resistance. While fitness costs can greatly influence the rate of resistance evolution, most available data related to Bt resistance have been obtained from laboratory-selected insect strains. In this article, we test the existence of fitness costs associated with high levels of field-evolved resistance to Bt maize event TC1507 in a strain of Spodoptera frugiperda (JE Smith) originated from maize fields in Puerto Rico. Fitness costs in resistant S. frugiperda were evaluated by comparing biological performance to susceptible insects when reared on meridic diet, maize or soybean leaf tissue, or cotton reproductive tissues. Parameters monitored included larval survival, larval and pupal weights, developmental time (larval and pupal), adult longevity, reproductive traits (fecundity and fertility), and sex ratio. We found that all monitored parameters were influenced to a similar extent by the host, independently of susceptibility to Bt maize. The only parameter that significantly differed between strains for all hosts was a longer larval developmental period in resistant S. frugiperda, which resulted in emergence asynchrony between susceptible and resistant adults. To test the relevance of fitness costs in resistant S. frugiperda, we performed a selection experiment to monitor the stability of resistance in a heterogeneous strain through 12 generations of rearing on meridic diet. Our data demonstrate lack of fitness costs relevant to stability of field-evolved resistance to Bt maize and help explain reported stability of field-evolved resistance in Puerto Rican populations of S. frugiperda.

  2. What are farmers really planting? Measuring the presence and effectiveness of Bt cotton in Pakistan.

    Directory of Open Access Journals (Sweden)

    David J Spielman

    Full Text Available Genetically modified, insect-resistant Bacillus thuringiensis (Bt cotton is cultivated extensively in Pakistan. Past studies, however, have raised concerns about the prevalence of Bt cotton varieties possessing weak or nonperforming insect-resistance traits conferred by the cry gene. We examine this issue using data drawn from a representative sample of cotton-growing households that were surveyed in six agroclimatic zones spanning 28 districts in Pakistan in 2013, as well as measurements of Cry protein levels in cotton tissue samples collected from the sampled households' main fields. The resultant dataset combines information from 593 sampled households with corresponding plant tissue diagnostics from 70 days after sowing, as well as information from 589 sampled households with corresponding diagnostics from 120 days after sowing. Our analysis indicates that 11 percent of farmers believed they were cultivating Bt cotton when, in fact, the Cry toxin was not present in the tested tissue at 70 days after sowing (i.e., a Type I error. The analysis further indicates that 5 percent of farmers believed they were cultivating non-Bt cotton when, in fact, the Cry toxin was present in the tested tissue (i.e., a Type II error. In addition, 17 percent of all sampled farmers were uncertain whether or not they were cultivating Bt cotton. Overall, 33 percent of farmers either did not know or were mistaken in their beliefs about the presence of the cry gene in the cotton they cultivated. Results also indicate that toxic protein levels in the plant tissue samples occurred below threshold levels for lethality in a significant percentage of cases, although these measurements may also be affected by factors related to tissue sample collection, handling, storage, and testing procedures. Nonetheless, results strongly suggest wide variability both in farmers' beliefs and in gene expression. Such variability has implications for policy and regulation in Pakistan

  3. Distribuição espacial de Aphis gossypii (Glover (Hemiptera, Aphididae e Bemisia tabaci (Gennadius biótipo B (Hemiptera, Aleyrodidae em algodoeiro Bt e não-Bt Spatial distribution of Aphis gossypii (Glover (Hemiptera, Aphididae and Bemisia tabaci (Gennadius biotype B (Hemiptera, Aleyrodidae on Bt and non-Bt cotton

    Directory of Open Access Journals (Sweden)

    Tatiana Rojas Rodrigues

    2010-03-01

    Full Text Available Distribuição espacial de Aphis gossypii (Glover (Hemiptera, Aphididae e Bemisia tabaci (Gennadius biótipo B (Hemiptera, Aleyrodidae em algodoeiro Bt e não-Bt. O estudo da distribuição espacial de adultos de Bemisia tabaci e de Aphis gossypii nas culturas do algodoeiro Bt e não-Bt é fundamental para a otimização de técnicas de amostragens, além de revelar diferenças de comportamento de espécies não-alvo dessa tecnologia Bt entre as duas cultivares. Nesse sentido, o experimento buscou investigar o padrão da distribuição espacial dessas espécies de insetos no algodoeiro convencional não-Bt e no cultivar Bt. As avaliações ocorreram em dois campos de 5.000 m² cada, nos quais se realizou 14 avaliações com contagem de adultos da mosca-branca e colônias de pulgões. Foram calculados os índices de agregação (razão variância/média, índice de Morisita e Expoente k da Distribuição Binomial Negativa e realizados os testes ajustes das classes numéricas de indivíduos encontradas e esperadas às distribuições teóricas de freqüência (Poisson, Binomial Negativa e Binomial Positiva. Todas as análises mostraram que, em ambas as cultivares, a distribuição espacial de B. tabaci ajustou-se a distribuição binomial negativa durante todo o período analisado, indicando que a cultivar transgênica não influenciou o padrão de distribuição agregada desse inseto. Já com relação às análises para A. gossypii, os índices de agregação apontaram distribuição agregada nas duas cultivares, mas as distribuições de freqüência permitiram concluir a ocorrência de distribuição agregada apenas no algodoeiro convencional, pois não houve nenhum ajuste para os dados na cultivar Bt. Isso indica que o algodão Bt alterou o padrão normal de dispersão dos pulgões no cultivo.The study of spatial distribution of the adults of Bemisia tabaci and the colonies of Aphis gossypii on Bt and non-Bt cotton crop is fundamental for

  4. Efficacy of genetically modified Bt toxins alone and in combinations against pink bollworm resistant to Cry1Ac and Cry2Ab

    Science.gov (United States)

    Evolution of resistance in pests threatens the long-term success of transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt). Previous work showed that genetically modified Bt toxins Cry1AbMod and Cry1AcMod effectively countered resistance to native Bt toxins Cry1Ab and ...

  5. Combined influence of Bt rice and rice dwarf virus on biological parameters of a non-target herbivore, Nephotettix cincticeps (Uhler) (Hemiptera: Cicadellidae)

    Science.gov (United States)

    The advent of genetically modified (GM) Bt rice creates the possibility of interactions among Bt crops, crop pathogens and non-target herbivores. In particular, information on how pathogen-infected Bt-expressing plants will influence non-target herbivores is necessary to predict the sustainability o...

  6. A highly active endo-levanase BT1760 of a dominant mammalian gut commensal Bacteroides thetaiotaomicron cleaves not only various bacterial levans, but also levan of timothy grass

    DEFF Research Database (Denmark)

    Mardo, Karin; Visnapuu, Triinu; Vija, Heiki

    2017-01-01

    -levanase BT1760. The FOS are consumed by B. thetaiotaomicron, but also by other gut bacteria, including health-promoting bifidobacteria and lactobacilli. Here we characterize biochemical properties of BT1760, including the activity of BT1760 on six bacterial levans synthesized by the levansucrase Lsc3...

  7. Influence of one or two Bt genes transgenic cotton free living nitrogen fixers and p-solubilising microorganisms in vertisols and alfisols

    Science.gov (United States)

    Sudha, T.; Babu, R.; Biradar, D. P.; Patil, V. C.; Shirnalli, G.

    2012-04-01

    India, the largest cotton grower in the world benefited from the cultivation of genetically modified Bt transgenic cotton. Bt cotton with the single gene (cry 1Ac) contributed to increased productivity over the last eight years. But in the recent years, there has been an increasing trend to adopt two genes (cry 1Ac and cry 2Ab) transgenic cotton in India. The two gene Bt cotton hybrids were planted over a large area (57%) during 2009 than the single gene Bt cotton hybrids. In this context, the field experiments were conducted in farmers field in both Vertisols and Alfisols during monsoon season of 2009 to study the effect of a single gene Bt hybrid (RCH-2Bt, JK-99Bt, Mallika Bt, MRC-6918 Bt, Brahma Bt, RCH-708 Bt, Bunny Bt) as well as two gene Bt hybrids (RCH-2 BGII Bt, Bunny BGII Bt) compared with the non genetically modified (non-Bt) hybrid (DHH-11) on the population of free living nitrogen fixing microorganisms (Azospirillum and methylotrophs) and P-solubilizers in two different soil types under rainfed situation. Observations on microbial population were recorded at flowering and at harvest in both the soil types. Results indicated a higher population of Azospirillum, methylotrophs and P-solubilisers in the rhizosphere grown with single or two gene Bt hybrid and non-Bt hybrid at flowering stage in both the soil types. In Vertisol, significantly higher population of methylotrophs in MRC-6918 Bt (30 x 102/g of soil), P-solubilizers in RCH-2 Bt (31x103/g of soil) and Azospirillum in RCH-708 Bt (0.79 x 106 /g of soil) was recorded as compared to non-Bt hybrid DHH-11 (2 x 102/g of soil, 12 x 103/g of soil, 0.54 x 106/g of soil), respectively. Whereas, in Alfisol, significantly higher population of methylotrophs in RCH-2 Bt (13x 102/g of soil), P-solubilisers in JK-99 Bt (38 x 103/g of soil) and Azospirillum in RCH-2Bt (0.57 x 106/g of soil) was recorded over non Bt hybrid DHH-11 (2x 102/g of soil, 13x 103/g of soil and 0.17 x106/g of soil) respectively. Our results

  8. Characterization of normal and waxy corn starch for bioethanol production.

    Science.gov (United States)

    Yangcheng, Hanyu; Jiang, Hongxin; Blanco, Michael; Jane, Jay-lin

    2013-01-16

    Objectives of this study were to compare ethanol production between normal and waxy corn using a cold fermentation process and to understand effects of starch structures and properties on ethanol production. Ethanol yields positively correlated (p starch contents of kernels of the normal and waxy corn. The average starch-ethanol conversion efficiency of waxy corn (93.0%) was substantially greater than that of normal corn (88.2%). Waxy corn starch consisted of very little amylose and mostly amylopectin that had a shorter average branch chain length than normal corn amylopectin. Regression analyses showed that average amylopectin branch chain lengths and percentage of long branch chains (DP > 37) of waxy corn starch negatively correlated with the starch hydrolysis rate and the ethanol yield. These results indicated that starch structures and properties of the normal and waxy corn had significant effects on the ethanol yield using a cold fermentation process.

  9. Recent advancement on chemical arsenal of Bt toxin and its application in pest management system in agricultural field.

    Science.gov (United States)

    Chattopadhyay, Pritam; Banerjee, Goutam

    2018-04-01

    Bacillus thuringiensis ( Bt ) is a Gram-positive, spore-forming, soil bacterium, which is very popular bio-control agent in agricultural and forestry. In general, B. thuringiensis secretes an array of insecticidal proteins including toxins produced during vegetative growth phase (such as secreted insecticidal protein, Sip; vegetative insecticidal proteins, Vip), parasporal crystalline δ-endotoxins produced during vegetative stationary phase (such as cytolytic toxin, Cyt; and crystal toxin, Cry), and β-exotoxins. Till date, a wide spectrum of Cry proteins has been reported and most of them belong to three-domain-Cry toxins, Bin-like toxin, and Etx_Mtx2-like toxins. To the best of our knowledge, neither Bt insecticidal toxins are exclusive to Bt nor all the strains of Bt are capable of producing insecticidal Bt toxins. The lacuna in their latest classification has also been discussed. In this review, the updated information regarding the insecticidal Bt toxins and their different mode of actions were summarized. Before applying the Bt toxins on agricultural field, the non-specific effects of toxins should be investigated. We also have summarized the problem of insect resistance and the strategies to combat with this problem. We strongly believe that this information will help a lot to the budding researchers in the field of modern pest control biotechnology.

  10. Larval Dispersal of Spodoptera frugiperda Strains on Bt Cotton: A Model for Understanding Resistance Evolution and Consequences for its Management.

    Science.gov (United States)

    Malaquias, José B; Godoy, Wesley A C; Garcia, Adriano G; Ramalho, Francisco de S; Omoto, Celso

    2017-11-23

    High dispersal of Lepidoptera larvae between non-Bt and Bt cotton plants can favour the evolution of insect resistance; however, information on host acceptance of neonates in tropical transgenic crops is scarce. Therefore, the purposes of this study were as follows: (i) to investigate the feeding behaviour of susceptible and Cry1F-resistant strains of Spodoptera frugiperda (J.E. Smith) on Bt and non-Bt cotton (Gossypium hirsutum L.) varieties and (ii) to understand the possible effects of cotton field contamination on the dispersal and infestation capacity of S. frugiperda larvae by using an individual-based model. The main results of this paper are as follows: (1) the highest post-feeding larval dispersal of the Cry1F-resistant strain occurred at an exposure time of 18-24 h; (2) via video tracking assays, we found that the least distance moved was by larvae resistant to Cry1F on non-Bt cotton; and (3) the model indicated differences in mobility capacity between Bt and non-Bt cotton. We conclude that resistant neonates exhibit sedentary behaviour. Our report represents the first findings concerning the fitness cost of larval behaviour traits of S. frugiperda associated with Cry1F resistance in Brazilian populations.

  11. Preparation of antioxidative corn protein hydrolysates, purification and evaluation of three novel corn antioxidant peptides.

    Science.gov (United States)

    Jin, Du-Xin; Liu, Xiao-Lan; Zheng, Xi-Qun; Wang, Xiao-Jie; He, Jun-Fang

    2016-08-01

    Corn gluten meal is a major co-product of corn wet milling. Corn gluten meal was hydrolyzed with Alcalase, Flavourzyme, Alcalase+Flavourzyme and Flavourzyme+Alcalase. At the substrate concentration of 10%, corn protein hydrolysate catalyzed by Alcalase had a degree of hydrolysis of 17.83%, which was higher than that by Flavourzyme (3.65%). The hydrolysate catalyzed by Alcalase+Flavourzyme exhibited better antioxidant activities and was further purified. Three novel antioxidant peptides were purified by a series of chromatographic techniques. Sequences of the three peptides were identified as Cys-Ser-Gln-Ala-Pro-Leu-Ala, Tyr-Pro-Lys-Leu-Ala-Pro-Asn-Glu and Tyr-Pro-Gln-Leu-Leu-Pro-Asn-Glu, respectively. Among the three peptides, Cys-Ser-Gln-Ala-Pro-Leu-Ala exhibited good reducing power and excellent scavenging capacities for DPPH radical and superoxide anion radical, with IC50 values of 0.116 and 0.39mg/ml, respectively. The results from our study indicate antioxidant potency of corn protein hydrolysates and peptides separated from corn gluten meal and can provide basic understanding for the application of corn protein hydrolysates as natural antioxidants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Influence of twin-screw extrusion on soluble arabinoxylans and corn fiber gum from corn fiber.

    Science.gov (United States)

    Singkhornart, Sasathorn; Lee, Seul Gi; Ryu, Gi Hyung

    2013-09-01

    The effect of feed moisture content and screw speed in the extrusion process with and without chemical pretreatment of corn fiber was investigated. Different chemical pretreatment methods (NaOH and H2 SO4 solution) were compared. The improvement of reducing sugar, soluble arabinoxylans (SAX) content and the yield of corn fiber gum was measured. A high reducing sugar content was obtained in the filtrate fraction from the extruded destarched corn fiber (EDCF) with H₂SO₄ pretreatment. Feed moisture content most effectively improved both reducing sugar and SAX content of filtrate. Increasing feed moisture content and screw speed resulted in a higher SAX content in the filtrate of the EDCF with NaOH pretreatment. The SAX content of the residual solid from the EDCF with NaOH pretreatment was higher compared to H₂SO₄ pretreated and unpretreated samples and significantly increased with decreasing feed moisture content. The screw speed did not have a major impact after enzyme hydrolysis. The yield of corn fiber gum was increased by 12% using NaOH pretreatment combined with extrusion process as compared to the destarched corn fiber. The results show the great potential of the extrusion process as an effective pretreatment for disruption the lignocelluloses of corn fiber, leading to conversion of cellulose to glucose and hemicelluloses to SAX and isolation of corn fiber gum. © 2013 Society of Chemical Industry.

  13. Cellular responses in Bacillus thuringiensis CS33 during bacteriophage BtCS33 infection.

    Science.gov (United States)

    Wu, Dandan; Yuan, Yihui; Liu, Pengming; Wu, Yan; Gao, Meiying

    2014-04-14

    Bacillus thuringiensis (Bt) has been widely used for 50years as a biopesticide for controlling insect pests. However, bacteriophage infection can cause failures in 50%-80% of the batches during Bt fermentation, resulting in severe losses. In the present work, the physiological and biochemical impacts of Bt strain CS33 have been studied during bacteriophage infection. This study adopted a gel-based proteomics approach to probe the sequential changed proteins in phage-infected Bt cells. To phage, it depressed the host energy metabolism by suppressing the respiration chain, the TCA cycle, and the utilization of PHB on one hand; on the other hand, it hijacked the host translational machine for its own macromolecular synthesis. To host, superinfection exclusion might be triggered by the changes of S-layer protein and flagella related proteins, which were located on the cell surface and might play as the candidates for the phage recognition. More importantly, the growth rate, cell mass, and ICPs yield were significantly decreased. The low yield of ICPs was mainly due to the suppressed utilization of PHB granules. Further functional study on these altered proteins may lead to a better understanding of the pathogenic mechanisms and the identification of new targets for phage control. B. thuringiensis (Bt) has been widely used for 50years as a safe biopesticide for controlling agricultural and sanitary insect pests. However, bacteriophage infection can cause severe losses during B. thuringiensis fermentation. The processes and consequences of interactions between bacteriophage and Bt were still poorly understood, and the molecular mechanisms involved were more unknown. This study adopted a gel-based proteomics approach to probe the physiological and biochemical impacts of Bt strain CS33 after phage-infection. The interactions between phage BtCS33 and its host Bt strain CS33 occurred mainly on four aspects. First, phage synthesized its nucleic acids through metabolic

  14. Progress of the BT-EdF-CEA project. The lithium polymer battery; Avancees du projet BT-EdF-CEA. Batterie lithium polymere

    Energy Technology Data Exchange (ETDEWEB)

    Marginedes, D.; Majastre, H. [Bollore Technologies, 29 - Quimper (France); Baudry, P.; Lascaud, S. [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches; Bloch, D.; Lebrun, N. [CEA Grenoble, CEREM, 38 (France)

    1996-12-31

    The lithium-polymer energy storage technology requires the production of thin films of huge surface. The BT-EdF-CEA consortium has studied the various manufacturing techniques of these films and their assembly. The process was chosen according to its productivity, low expensiveness, ecological impact and energy performances with capacities reaching 40 Ah. This paper explains: the objectives and specifications of the project, the advantage of the consortium and the role of the different partners, the results (coating, dry extrusion and battery element manufacturing techniques), and the electrochemical performances of the elements. (J.S.)

  15. A method for sampling waste corn

    Science.gov (United States)

    Frederick, R.B.; Klaas, E.E.; Baldassarre, G.A.; Reinecke, K.J.

    1984-01-01

    Corn had become one of the most important wildlife food in the United States. It is eaten by a wide variety of animals, including white-tailed deer (Odocoileus virginianus ), raccoon (Procyon lotor ), ring-necked pheasant (Phasianus colchicus , wild turkey (Meleagris gallopavo ), and many species of aquatic birds. Damage to unharvested crops had been documented, but many birds and mammals eat waste grain after harvest and do not conflict with agriculture. A good method for measuring waste-corn availability can be essential to studies concerning food density and food and feeding habits of field-feeding wildlife. Previous methods were developed primarily for approximating losses due to harvest machinery. In this paper, a method is described for estimating the amount of waste corn potentially available to wildlife. Detection of temporal changes in food availability and differences caused by agricultural operations (e.g., recently harvested stubble fields vs. plowed fields) are discussed.

  16. Enzymatic hydrolysis of corn bran arabinoxylan

    DEFF Research Database (Denmark)

    Agger, Jane

    observed that different particle size fractions from corn bran are not uniformly composed. The content of monosaccharides varies and results in differences in content and composition of cellulose and arabinoxylan. These differences in biomass composition may very well also be part of the explanation why...... bran fraction. Once the arabinoxylan structure is free of the cell wall matrix the hydrolysis seem to be restricted due to steric hindrance or lack of additional enzymes to catalyse the hydrolysis of certain unusual bonds. In particular, it is of outmost importance to target arabinosyl substitutions...... by completing the knowledge about corn bran arabinoxylan, which can then lead to the identification of missing, central enzyme activities, and thereby also make the work on corn bran generic. The thesis is based upon the scientific publications produced during the last four years and they represent...

  17. Corn Cultivation to Reduce the Mycotoxin Contamination

    Directory of Open Access Journals (Sweden)

    Yangseon Kim

    2017-09-01

    Full Text Available The effects of insecticide and fungicide treatment were investigated to reduce mycotoxin contamination of corn (Zea mays L. seeds. Deoxynivalenol and zearalenone contents were reduced in the treated seeds, but aflatoxin, ochratoxin A, fumonisin, and T-2 toxin were not effective by chemical treatments. The chemical treatment did not affect the growth of saprophyte, but inhibited the pathogenic fungi such as Fusarium verticillioides, F. graminearum and F. equiseti. Myotoxin contents at different harvesting time were compared. As the harvest time was delayed, both levels of deoxynivalenol and zearalenone and frequency of Fusarium spp. increased. However, the major nutrient contents of corn seeds were not affected by harvesting period. These results show that chemical treatments are necessary to reduce the fungal contamination of corn and harvest without delay is important as well.

  18. Resistance to Spodoptera frugiperda (Lepidoptera: Noctuidae) and Euxesta stigmatias (Diptera: Ulidiidae) in sweet corn derived from exogenous and endogenous genetic systems.

    Science.gov (United States)

    Nuessly, G S; Scully, B T; Hentz, M G; Beiriger, R; Snook, M E; Widstrom, N W

    2007-12-01

    Field trials using Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) and Euxesta stigmatias Loew (Diptera: Ulidiidae) were conducted to evaluate resistance and potential damage interactions between these two primary corn, Zea mays L., pests against Lepidoptera-resistant corn varieties derived from both endogenous and exogenous sources. The endogenous source of resistance was maysin, a C-glycosyl flavone produced in high concentrations in varieties 'Zapalote Chico 2451' and 'Zapalote Chico sh2'. The exogenous resistance source was the Bacillus thuringiensis (Bt)11 gene that expresses Cry1A(b) insecticidal protein found in 'Attribute GSS-0966'. Damage by the two pests was compared among these resistant varieties and the susceptible 'Primetime'. Single-species tests determined that the Zapalote Chico varieties and GSS-0966 effectively reduced S. frugiperda larval damage compared with Primetime. E. stigmatias larval damage was less in the Zapalote Chico varieties than the other varieties in single-species tests. E. stigmatias damage was greater on S. frugiperda-infested versus S. frugiperda-excluded ears. Ears with S. frugiperda damage to husk, silk and kernels had greater E. stigmatias damage than ears with less S. frugiperda damage. Reversed phase high-performance liquid chromatography analysis of nonpollinated corn silk collected from field plots determined that isoorientin, maysin, and apimaysin plus 3'-methoxymaysin concentrations followed the order Zapalote Chico sh2 > Zapalote Chico 2451 > Attribute GSS-0966 = Primetime. Chlorogenic acid concentrations were greatest in Zapalote Chico 2451. The two high maysin Zapalote Chico varieties did as well against fall armyworm as the Bt-enhanced GSS-0966, and they outperformed GSS-0966 against E. stigmatias.

  19. 21 CFR 137.260 - Enriched corn meals.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Enriched corn meals. 137.260 Section 137.260 Food... Flours and Related Products § 137.260 Enriched corn meals. (a) Enriched corn meals are the foods, each of which conforms to the definition and standard of identity prescribed for a kind of corn meal by §§ 137...

  20. 21 CFR 137.250 - White corn meal.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false White corn meal. 137.250 Section 137.250 Food and... Related Products § 137.250 White corn meal. (a) White corn meal is the food prepared by so grinding cleaned white corn that when tested by the method prescribed in paragraph (b)(2) of this section not less...

  1. Corn cob lightweight concrete for non-structural applications

    OpenAIRE

    Pinto, J.; Vieira, J.; Pereira, H.; Jacinto, C.; Vilela, P.; Paiva, A.; Pereira, S.; Cunha, V.; Varum, H.

    2012-01-01

    A lightweight concrete using granulated corn cob (without corn) as an aggregate is proposed in this research work. Taking into account that corn cob, after extracting the corn, is generally considered an agricultural waste, an interesting economic and sustainable benefit may result by using it as a building material. Therefore, it can be an alternative sustainable lightweight aggregate solution in comparison to the most currently applied ones such as expanded clay, particles of co...

  2. Laboratory studies of the effects of reduced prey choice caused by Bt plants on a predatory insect.

    Science.gov (United States)

    Schuler, T H; Clark, A J; Clark, S J; Poppy, G M; Stewart, C N; Denholm, I

    2005-06-01

    Crops transformed to express Bacillus thuringiensis (Bt) toxins can cause close to 100% mortality of certain target pest species. This study assessed the effect of target pest reduction on the predatory insect Chrysoperla carnea (Stephens) in the presence of alternative prey. Numbers of lacewings recovered from Bt oilseed rape (cultivar Oscar, event O52) did not differ significantly from numbers of lacewings recovered from conventional oilseed rape in cage experiments with the target pest Plutella xylostella (Linnaeus) and the non-target pest Myzus persicae (Sulzer) when aphid densities were high. However, significantly fewer lacewings were recovered from Bt plants as aphid densities were lowered. Lacewing weights were not affected by plant type.

  3. 21 CFR 184.1866 - High fructose corn syrup.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true High fructose corn syrup. 184.1866 Section 184.1866... Listing of Specific Substances Affirmed as GRAS § 184.1866 High fructose corn syrup. (a) High fructose corn syrup, a sweet, nutritive saccharide mixture containing either approximately 42 or 55 percent...

  4. 21 CFR 573.530 - Hydrogenated corn syrup.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogenated corn syrup. 573.530 Section 573.530... Additive Listing § 573.530 Hydrogenated corn syrup. (a) Identity. The product is produced by hydrogenation of corn syrup over a nickel catalyst. (b) Specifications. The product contains 70 percent...

  5. 21 CFR 73.315 - Corn endosperm oil.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Corn endosperm oil. 73.315 Section 73.315 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.315 Corn endosperm oil. (a) Identity. (1) The color additive corn endosperm oil is a reddish-brown liquid composed chiefly of glycerides, fatty acids, sitosterols...

  6. Corn Clubs: Building the Foundation for Agricultural and Extension Education

    Science.gov (United States)

    Uricchio, Cassandra; Moore, Gary; Coley, Michael

    2013-01-01

    Corn clubs played an important role in improving agriculture at the turn of the 20th century. Corn clubs were local organizations consisting of boys who cultivated corn on one acre of land under the supervision of a local club leader. The purpose of this historical research study was to document the organization, operation, and outcomes of corn…

  7. 7 CFR 407.11 - Group risk plan for corn.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Group risk plan for corn. 407.11 Section 407.11..., DEPARTMENT OF AGRICULTURE GROUP RISK PLAN OF INSURANCE REGULATIONS § 407.11 Group risk plan for corn. The provisions of the Group Risk Plan for Corn for the 2000 and succeeding crop years are as follows: 1...

  8. Nutritional qualities of corn cob and waste paper incubated with ...

    African Journals Online (AJOL)

    Studies were conducted to evaluate corn cob and waste paper cultured with edible mushroom (Pleurotus sajor) as a mean of improving their nutritive value for livestock animals. Waste paper and corn cob were 14.2 and 47.7% DM respectively. Crude fibre degradation was 25.0% for corn cob and 7.21% for waste paper ...

  9. Physicochemical and sensory qualities of spiced soy-corn milk ...

    African Journals Online (AJOL)

    Soy-corn milk type was produced from a blend of soybean milk and corn milk extract at a ratio of 3:1. The soy-corn milk type was spiced with ginger and garlic extract respectively to improve the taste. Total dissolved solid (TDS), total titrable acidity (TTA) specific gravity (SG), apparent colloidal stability, pH and sensory ...

  10. 21 CFR 137.211 - White corn flour.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false White corn flour. 137.211 Section 137.211 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Related Products § 137.211 White corn flour. (a) White corn flour is the food prepared by so grinding and...

  11. 21 CFR 137.255 - Bolted white corn meal.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Bolted white corn meal. 137.255 Section 137.255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Flours and Related Products § 137.255 Bolted white corn meal. (a) Bolted white corn meal is the food...

  12. 21 CFR 137.215 - Yellow corn flour.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Yellow corn flour. 137.215 Section 137.215 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... standard of identity prescribed by § 137.211 for white corn flour except that cleaned yellow corn is used...

  13. 21 CFR 137.265 - Degerminated white corn meal.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Degerminated white corn meal. 137.265 Section 137.265 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... meal, degermed white corn meal, is the food prepared by grinding cleaned white corn and removing bran...

  14. 21 CFR 137.275 - Yellow corn meal.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Yellow corn meal. 137.275 Section 137.275 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... identity prescribed by § 137.250 for white corn meal except that cleaned yellow corn is used instead of...

  15. Updates to the Corn Ethanol Pathway and Development of an Integrated Corn and Corn Stover Ethanol Pathway in the GREET™ Model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Wang, Michael Q. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division

    2014-09-01

    Corn ethanol, a first-generation biofuel, is the predominant biofuel in the United States. In 2013, the total U.S. ethanol fuel production was 13.3 billion gallons, over 95% of which was produced from corn (RFA, 2014). The 2013 total renewable fuel mandate was 16.6 billion gallons according to the Energy Independence and Security Act (EISA) (U.S. Congress, 2007). Furthermore, until 2020, corn ethanol will make up a large portion of the renewable fuel volume mandated by Renewable Fuels Standard (RFS2). For the GREET1_2014 release, the corn ethanol pathway was subject to updates reflecting changes in corn agriculture and at corn ethanol plants. In the latter case, we especially focused on the incorporation of corn oil as a corn ethanol plant co-product. Section 2 covers these updates. In addition, GREET now includes options to integrate corn grain and corn stover ethanol production on the field and at the biorefinery. These changes are the focus of Section 3.

  16. Spatial Distribution of Eggs of Alabama argillacea Hübner and Heliothis virescens Fabricius (Lepidoptera: Noctuidae on Bt and non-BtCotton

    Directory of Open Access Journals (Sweden)

    TATIANA R. RODRIGUES

    2015-12-01

    Full Text Available ABSTRACT Among the options to control Alabama argillacea (Hübner, 1818 and Heliothis virescens (Fabricius, 1781 on cotton, insecticide spraying and biological control have been extensively used. The GM'Bt' cotton has been introduced as an extremely viable alternative, but it is yet not known how transgenic plants affect populations of organisms that are interrelated in an agroecosystem. For this reason, it is important to know how the spatial arrangement of pests and beneficial insect are affected, which may call for changes in the methods used for sampling these species. This study was conducted with the goal to investigate the pattern of spatial distribution of eggs of A. argillacea and H. virescens in DeltaOpalTM (non-Bt and DP90BTMBt cotton cultivars. Data were collected during the agricultural year 2006/2007 in two areas of 5,000 m2, located in in the district of Nova América, Caarapó municipality. In each sampling area, comprising 100 plots of 50 m2, 15 evaluations were performed on two plants per plot. The sampling consisted in counting the eggs. The aggregation index (variance/mean ratio, Morisita index and exponent k of the negative binomial distribution and chi-square fit of the observed and expected values to the theoretical frequency distribution (Poisson, Binomial and Negative Binomial Positive, showed that in both cultivars, the eggs of these species are distributed according to the aggregate distribution model, fitting the pattern of negative binomial distribution.

  17. Evaluating corn starch and corn stover biochar as renewable filler in carboxylated styrene-butadiene rubber composites

    Science.gov (United States)

    Corn starch, corn flour, and corn stover biochar were evaluated as potential renewable substitutes for carbon black as filler in rubber composites using carboxylated styrene-butadiene as the rubber matrix. Previous work has shown that starch-based fillers have very good reinforcement properties at t...

  18. Effect of Bt maize on the plant-aphid-parasitoid tritrophic relationships

    Czech Academy of Sciences Publication Activity Database

    Lumbierres, B.; Starý, Petr; Pons, X.

    2011-01-01

    Roč. 56, č. 2 (2011), s. 133-143 ISSN 1386-6141 Grant - others:Ministry of Education and Science(ES) AGL2002-0204; Ministry of Education and Science(ES) AP2002-(4104) Institutional research plan: CEZ:AV0Z50070508 Keywords : transgenic Bt maize * Aphididae * Rhopalosiphum padi Subject RIV: EH - Ecology, Behaviour Impact factor: 1.927, year: 2011

  19. Binding and Oligomerization of Modified and Native Bt Toxins in Resistant and Susceptible Pink Bollworm.

    Directory of Open Access Journals (Sweden)

    Josue Ocelotl

    Full Text Available Insecticidal proteins from Bacillus thuringiensis (Bt are used extensively in sprays and transgenic crops for pest control, but their efficacy is reduced when pests evolve resistance. Better understanding of the mode of action of Bt toxins and the mechanisms of insect resistance is needed to enhance the durability of these important alternatives to conventional insecticides. Mode of action models agree that binding of Bt toxins to midgut proteins such as cadherin is essential for toxicity, but some details remain unresolved, such as the role of toxin oligomers. In this study, we evaluated how Bt toxin Cry1Ac and its genetically engineered counterpart Cry1AcMod interact with brush border membrane vesicles (BBMV from resistant and susceptible larvae of Pectinophora gossypiella (pink bollworm, a global pest of cotton. Compared with Cry1Ac, Cry1AcMod lacks 56 amino acids at the amino-terminus including helix α-1; previous work showed that Cry1AcMod formed oligomers in vitro without cadherin and killed P. gossypiella larvae harboring cadherin mutations linked with >1000-fold resistance to Cry1Ac. Here we found that resistance to Cry1Ac was associated with reduced oligomer formation and insertion. In contrast, Cry1AcMod formed oligomers in BBMV from resistant larvae. These results confirm the role of cadherin in oligomerization of Cry1Ac in susceptible larvae and imply that forming oligomers without cadherin promotes toxicity of Cry1AcMod against resistant P. gossypiella larvae that have cadherin mutations.

  20. Impact of violated high-dose refuge assumptions on evolution of Bt resistance.

    Science.gov (United States)

    Campagne, Pascal; Smouse, Peter E; Pasquet, Rémy; Silvain, Jean-François; Le Ru, Bruno; Van den Berg, Johnnie

    2016-04-01

    Transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been widely and successfully deployed for the control of target pests, while allowing a substantial reduction in insecticide use. The evolution of resistance (a heritable decrease in susceptibility to Bt toxins) can pose a threat to sustained control of target pests, but a high-dose refuge (HDR) management strategy has been key to delaying countervailing evolution of Bt resistance. The HDR strategy relies on the mating frequency between susceptible and resistant individuals, so either partial dominance of resistant alleles or nonrandom mating in the pest population itself could elevate the pace of resistance evolution. Using classic Wright-Fisher genetic models, we investigated the impact of deviations from standard refuge model assumptions on resistance evolution in the pest populations. We show that when Bt selection is strong, even deviations from random mating and/or strictly recessive resistance that are below the threshold of detection can yield dramatic increases in the pace of resistance evolution. Resistance evolution is hastened whenever the order of magnitude of model violations exceeds the initial frequency of resistant alleles. We also show that the existence of a fitness cost for resistant individuals on the refuge crop cannot easily overcome the effect of violated HDR assumptions. We propose a parametrically explicit framework that enables both comparison of various field situations and model inference. Using this model, we propose novel empiric estimators of the pace of resistance evolution (and time to loss of control), whose simple calculation relies on the observed change in resistance allele frequency.

  1. Identification of feeding stimulants in corn roots for western corn rootworm (Coleoptera: Chrysomelidae) larvae.

    Science.gov (United States)

    Bernklau, E J; Bjostad, L B

    2008-04-01

    Using a bioassay-driven approach, we have isolated and identified a blend of compounds from the roots of germinating corn, Zea mays L., that serve as feeding stimulants for neonate western corn rootworm larvae, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). The active blend is a combination of simple sugars (30:4:4 mg/ml glucose:fructose:sucrose in the corn root) plus at least one of the free fatty acids in germinating corn roots (2:5 mg/ml oleic acid:linoleic acid in the corn root). When an extract of germinating corn was partitioned into an ethyl acetate fraction and an aqueous fraction, full feeding occurred only when the two fractions were recombined, indicating that the phagostimulant was comprised of both polar and nonpolar components. Gas chromatography-mass spectrometry analysis of root extracts from germinating corn seedlings revealed a blend of 20 compounds from a variety of chemical classes, including small sugars, diacids, amino acids, inorganic compounds, and free fatty acids. When the major components were tested in feeding bioassays, the sugars and lipids were shown to be essential for feeding by larvae, but the two classes of compounds were only effective when combined. The sugars alone elicited feeding by only 40% of larvae, but the percentage of larvae feeding was increased significantly with the addition of linoleic acid (91.7% larvae feeding) or oleic acid (85.8% larvae feeding). The amino acids alone were not essential elements for feeding by western corn rootworm larvae.

  2. An Economic Analysis of Corn-based Ethanol Production

    OpenAIRE

    Koo, Won W.; Taylor, Richard D.

    2008-01-01

    A global multi-commodity simulation model was developed to estimate the impact of changes in ethanol production on the U.S. corn industry. Increased ethanol production under the Energy Acts of 2005 and 2007 resulted in a significant increase in the price of corn. However, for corn-based ethanol production, the break-even price of corn is approximately $4.52 per bushel with a federal subsidy of $0.51 per gallon of pure ethanol and $2.50 gasoline. With a corn price of $4.52, the economically de...

  3. Larval development of Spodoptera eridania (Cramer fed on leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 proteins and its non-Bt isoline

    Directory of Open Access Journals (Sweden)

    Orcial Ceolin Bortolotto

    2015-03-01

    Full Text Available This study aimed to evaluate, in controlled laboratory conditions (temperature of 25±2 °C, relative humidity of 60±10%, and 14/10 h L/D photoperiod, the larval development of Spodoptera eridania (Cramer, 1784 (Lepidoptera, Noctuidae fed with leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 insecticide proteins and its non-Bt isoline. Maize leaves triggered 100% of mortality on S. eridania larvae independently of being Bt or non-Bt plants. However, it was observed that in overall Bt maize (expressing a single or pyramided protein slightly affects the larval development of S. eridania, even under reduced leaf consumption. Therefore, these results showed that Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 can affect the larval development of S. eridania, although it is not a target pest of this plant; however, more research is needed to better understand this evidence. Finally, this study confirms that non-Bt maize leaves are unsuitable food source to S. eridania larvae, suggesting that they are not a potential pest in maize fields.

  4. Localization of xanthine oxidoreductase activity using the tissue protectant polyvinyl alcohol and final electron acceptor Tetranitro BT

    NARCIS (Netherlands)

    Kooij, A.; Frederiks, W. M.; Gossrau, R.; van Noorden, C. J.

    1991-01-01

    We have detected xanthine oxidoreductase activity in unfixed cryostat sections of rat and chicken liver, rat duodenum, and bovine mammary gland using the tissue protectant polyvinyl alcohol, the electron carrier 1-methoxyphenazine methosulfate, the final electron acceptor Tetranitro BT, and

  5. Structure of BT-3984, a member of the SusD/RagB family of nutrient-binding molecules

    International Nuclear Information System (INIS)

    Bakolitsa, Constantina; Xu, Qingping; Rife, Christopher L.; Abdubek, Polat; Astakhova, Tamara; Axelrod, Herbert L.; Carlton, Dennis; Chen, Connie; Chiu, Hsiu-Ju; Clayton, Thomas; Das, Debanu; Deller, Marc C.; Duan, Lian; Ellrott, Kyle; Farr, Carol L.; Feuerhelm, Julie; Grant, Joanna C.; Grzechnik, Anna; Han, Gye Won; Jaroszewski, Lukasz; Jin, Kevin K.; Klock, Heath E.; Knuth, Mark W.; Kozbial, Piotr; Krishna, S. Sri; Kumar, Abhinav; Lam, Winnie W.; Marciano, David; McMullan, Daniel; Miller, Mitchell D.; Morse, Andrew T.; Nigoghossian, Edward; Nopakun, Amanda; Okach, Linda; Puckett, Christina; Reyes, Ron; Tien, Henry J.; Trame, Christine B.; Bedem, Henry van den; Weekes, Dana; Hodgson, Keith O.; Wooley, John; Elsliger, Marc-André; Deacon, Ashley M.; Godzik, Adam; Lesley, Scott A.; Wilson, Ian A.

    2010-01-01

    The crystal structure of BT-3984, a SusD-family protein, reveals a TPR N-terminal region providing support for a loop-rich C-terminal subdomain and suggests possible interfaces involved in sus complex formation. The crystal structure of the Bacteroides thetaiotaomicron protein BT-3984 was determined to a resolution of 1.7 Å and was the first structure to be determined from the extensive SusD family of polysaccharide-binding proteins. SusD is an essential component of the sus operon that defines the paradigm for glycan utilization in dominant members of the human gut microbiota. Structural analysis of BT-3984 revealed an N-terminal region containing several tetratricopeptide repeats (TPRs), while the signature C-terminal region is less structured and contains extensive loop regions. Sequence and structure analysis of BT-3984 suggests the presence of binding interfaces for other proteins from the polysaccharide-utilization complex

  6. Fructose and high fructose corn syrup

    Science.gov (United States)

    Fructose, a monosaccharide, is naturally present in fruits, vegetables and honey, usually accompanied by other sugars including glucose and the disaccharide sucrose. It is also found as a component of sweeteners used in many processed food products, usually as sucrose or high fructose corn syrup (HF...

  7. 21 CFR 155.130 - Canned corn.

    Science.gov (United States)

    2010-04-01

    ... sweet corn packed with a suitable liquid packing medium which may include water and the creamy component...) Lemon juice or concentrated lemon juice. (d) Butter or margarine in a quantity not less than 3 percent... husk per 400 g. (14 ounces) of drained weight. Place all pieces of cob under a measured amount of water...

  8. Producing ergosterol from corn straw hydrolysates using ...

    African Journals Online (AJOL)

    Ergosterol is an economically important metabolite produced by Saccharomyces cerevisiae. In this study, the production of ergosterol by the strain using corn straw as an inexpensive carbon source was investigated. The total yield of ergosterol was determined by both the biomass and ergosterol content in yeast cells which ...

  9. Experimental Viscoelastic Characterization of Corn Cob Composited ...

    African Journals Online (AJOL)

    The nature of viscoelasticity in biomateria1s and the techniques for characterizing their rheological properties were reviewed. Relaxation tests were performed with cylindrical samples of corn cob composites which were initially subjected to radial compression. It was found that a Maxwell model composed of two simple ...

  10. experimental viscoelastic characterization of corn cob composites ...

    African Journals Online (AJOL)

    Dr Obe

    static radial compression, determine a viscoelastic or rheological model for the tested corn cob samples, and investigate the effects of moisture content and rate of loading on the viscoelastic constants that characterize the ... exchange of kinetic energy on that scale. As any other model, mechanical models give at most part ...

  11. Current trends in Bt crops and their fate on associated microbial community dynamics: a review.

    Science.gov (United States)

    Singh, Amit Kishore; Dubey, Suresh Kumar

    2016-05-01

    Cry protein expressing insect-resistant trait is mostly deployed to control major devastating pests and minimize reliance on the conventional pesticides. However, the ethical and environmental issues are the major constraints in their acceptance, and consequently, the cultivation of genetically modified (GM) crops has invited intense debate. Since root exudates of Bacillus thuringiensis (Bt) crops harbor the insecticidal protein, there is a growing concern about the release and accumulation of soil-adsorbed Cry proteins and their impact on non-target microorganisms and soil microbial processes. This review pertains to reports from the laboratory studies and field trials to assess the Bt toxin proteins in soil microbes and the processes determining the soil quality in conjunction with the existing hypothesis and molecular approaches to elucidate the risk posed by the GM crops. Ecological perturbations hinder the risk aspect of soil microbiota in response to GM crops. Therefore, extensive research based on in vivo and interpretation of results using high-throughput techniques such as NGS on risk assessment are imperative to evaluate the impact of Bt crops to resolve the controversy related to their commercialization. But more studies are needed on the risk associated with stacked traits. Such studies would strengthen our knowledge about the plant-microbe interactions.

  12. Comparative proteomics of Bt-transgenic and non-transgenic cotton leaves.

    Science.gov (United States)

    Wang, Limin; Wang, Xuchu; Jin, Xiang; Jia, Ruizong; Huang, Qixing; Tan, Yanhua; Guo, Anping

    2015-01-01

    As the rapid growth of the commercialized acreage in genetically modified (GM) crops, the unintended effects of GM crops' biosafety assessment have been given much attention. To investigate whether transgenic events cause unintended effects, comparative proteomics of cotton leaves between the commercial transgenic Bt + CpTI cotton SGK321 (BT) clone and its non-transgenic parental counterpart SY321 wild type (WT) was performed. Using enzyme linked immunosorbent assay (ELISA), Cry1Ac toxin protein was detected in the BT leaves, while its content was only 0.31 pg/g. By 2-DE, 58 differentially expressed proteins (DEPs) were detected. Among them 35 were identified by MS. These identified DEPs were mainly involved in carbohydrate transport and metabolism, chaperones related to post-translational modification and energy production. Pathway analysis revealed that most of the DEPs were implicated in carbon fixation and photosynthesis, glyoxylate and dicarboxylate metabolism, and oxidative pentose phosphate pathway. Thirteen identified proteins were involved in protein-protein interaction. The protein interactions were mainly involved in photosynthesis and energy metabolite pathway. Our study demonstrated that exogenous DNA in a host cotton genome can affect the plant growth and photosynthesis. Although some unintended variations of proteins were found between BT and WT cotton, no toxic proteins or allergens were detected. This study verified genetically modified operation did not sharply alter cotton leaf proteome, and the target proteins were hardly checked by traditional proteomic analysis.

  13. Complete genome sequence and bioinformatics analyses of Bacillus thuringiensis strain BM-BT15426.

    Science.gov (United States)

    Liu, Junyan; Li, Lin; Peters, Brian M; Li, Bing; Chen, Dingqiang; Xu, Zhenbo; Shirtliff, Mark E

    2017-07-01

    This study aimed to investigate the genetic characteristics of Bacillus thuringiensis strain BM-BT15426. B. thuringiensis strain was identified by sequencing the PCR product (amplifying 16S rRNA gene) using ABI Prism 377 DNA Sequencer. The genome was sequenced using PacBio RS II sequencers and assembled de novo using HGAP. Also, further genome annotation was performed. The genome of B. thuringiensis strain BM-BT15426 has a length of 5,246,329 bp and contains 5409 predicted genes with an average G + C content of 35.40%. Three genes were involved in the "Infectious diseases: Amoebiasis" pathway. A total of 21 virulence factors and 9 antibiotic resistant genes were identified. The major pathogenic factors of B. thuringiensis strain BM-BT15426 were identified through complete genome sequencing and bioinformatics analyses which contributes to further study on pathogenic mechanism and phenotype of B. thuringiensis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Pulsed Dose Rate (PDR - BT) brachytherapy in treatment of breast cancer

    International Nuclear Information System (INIS)

    Skowronek, J.

    2007-01-01

    Breast conserving surgery (BCS) and radiotherapy (EBRT) of the conserved breast became widely accepted in the last decades for the treatment of early invasive breast cancer. The standard technique of RT after breast conservation is to treat the whole breast up to a total dose of 45 to 50 Gy. Initially brachytherapy for breast cancer was used in addition of external radiation to boost a portion of the breast to higher doses. However, over the past 10 years, the application of brachytherapy in breast cancer has changed. In early stage breast cancer, research has shown that the area that requires radiation treatment to prevent the cancer from returning is the breast tissue that surrounds the area where the initial cancer was removed. Because this typically includes only a part of the breast, brachytherapy is now being used to treat the targeted portion of the breast and as a result allows accelerated delivery of the radiation dose so that treatment is completed in four to five days. Another indications for PDR - BT as a part of treatment in locally advanced breast cancer or as a palliative treatment are discussed in the paper, too. Preliminary results with PDR - BT boost technique are promising. However, more experience and longer follow-up are required to define whether these methods might improve local tumor control for breast cancer patients. In this article the current status, indications, technical aspects and published results of PDR brachytherapy (PDR - BT) in breast cancer treatment are reviewed. (author)

  15. The permittivity and refractive index measurements of doped barium titanate (BT-BCN)

    Science.gov (United States)

    Meeker, Michael A.; Kundu, Souvik; Maurya, Deepam; Kang, Min-Gyu; Sosa, Alejandro; Mudiyanselage, Rathsara R. H. H.; Clavel, Michael; Gollapudi, Sreenivasulu; Hudait, Mantu K.; Priya, Shashank; Khodaparast, Giti A.

    2017-11-01

    While piezoelectric- ferroelectric materials offer great potential for nonvolatile random access memory, most commonly implemented ferroelectrics contain lead which imposes a challenge in meeting environmental regulations. One promising candidate for lead-free, ferroelectric material based memory is (1 - x) BaTiO3 - xBa(Cu1 / 3 Nb2 / 3) O3 (BT-BCN), x = 0.025 . The samples studied here were grown on a Si substrate with an HfO2 buffer layer, thereby preventing the interdiffusion of BT-BTCN into Si. This study provides further insight into the physical behavior of BT-BCN that will strengthen the foundation for developing switching devices. The sample thicknesses ranged from 1.5 to 120 nm, and piezoelectric force microscopy was employed in order to understand the local ferroelectric behaviors. Dielectric constant as a function of frequency demonstrated enhanced frequency dispersion indicating the polar nature of the composition. The relative permittivity was found to change significantly with varying bias voltage and exhibited a tunability of 82%. The difference in the peak position during up and down sweeps is due to the presence of the spontaneous polarization. Furthermore, reflectometry was performed to determine the refractive index of samples with differing thicknesses. Our results demonstrate that refractive indices are similar to that of barium titanate. This is a promising result indicating that improved ferroelectric properties are obtained without compromising the optical properties.

  16. Implications of corn prices on water footprints of bioethanol.

    Science.gov (United States)

    Suh, Kyo; Suh, Sangwon; Smith, Timothy

    2011-04-01

    Previously reported water footprints (WFPs) of corn ethanol have been estimated based on the assumption that corn ethanol feedstock could be supplied by the same states where the corn is grown. However, ethanol conversion facilities may choose out-of-state feedstock suppliers depending on the total price of feedstock they have to pay including both the corn price and transportation costs. The purpose of this study is to evaluate the WFPs and total water use (TWU) of corn ethanol considering an optimal allocation of corn with heterogeneous corn feedstock prices across states. The results show that the WFPs of corn ethanol are less than 100 l of water per liter of ethanol (Lw/Le) for all ethanol-producing states based on both the 2008 corn price and transportation costs for rail and truck. Results also reveal that WFPs are very sensitive to the market price of corn and that additional greenhouse gas emissions due to corn trade between states are not significant. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Resistance to dual-gene Bt maize in Spodoptera frugiperda: selection, inheritance, and cross-resistance to other transgenic events

    OpenAIRE

    Santos-Amaya, Oscar F.; Rodrigues, Jo?o V. C.; Souza, Thadeu C.; Tavares, Cl?bson S.; Campos, Silverio O.; Guedes, Raul N.C.; Pereira, Eliseu J.G.

    2015-01-01

    Transgenic crop ?pyramids? producing two or more Bacillus thuringiensis (Bt) toxins active against the same pest are used to delay evolution of resistance in insect pest populations. Laboratory and greenhouse experiments were performed with fall armyworm, Spodoptera frugiperda, to characterize resistance to Bt maize producing Cry1A.105 and Cry2Ab and test some assumptions of the ?pyramid? resistance management strategy. Selection of a field-derived strain of S. frugiperda already resistant to...

  18. Delta's Key to the Next Generation TOEFL[R] Test: Six Practice Tests for the iBT

    Science.gov (United States)

    Gallagher, Nancy

    2012-01-01

    Six Practice Tests for the iBT gives students plenty of practice as they prepare for the Internet-based TOEFL (iBT) or the new form of the institutional TOEFL (ITP). This new book/audio set contains a concise description of the TOEFL and the types of questions in each section, as well as six full-length tests that have not been published before.…

  19. Bt Jute Expressing Fused δ-Endotoxin Cry1Ab/Ac for Resistance to Lepidopteran Pests

    Science.gov (United States)

    Majumder, Shuvobrata; Sarkar, Chirabrata; Saha, Prosanta; Gotyal, Bheemanna S.; Satpathy, Subrata; Datta, Karabi; Datta, Swapan K.

    2018-01-01

    Jute (Corchorus sp.) is naturally occurring, biodegradable, lignocellulosic-long, silky, golden shiny fiber producing plant that has great demands globally. Paper and textile industries are interested in jute because of the easy availability, non-toxicity and high yield of cellulosic biomass produced per acre in cultivation. Jute is the major and most industrially used bast fiber-producing crop in the world and it needs protection from insect pest infestation that decreases its yield and quality. Single locus integration of the synthetically fused cry1Ab/Ac gene of Bacillus thuringiensis (Bt) in Corchorus capsularis (JRC 321) by Agrobacterium tumefaciens-mediated shoot tip transformation provided 5 potent Bt jute lines BT1, BT2, BT4, BT7 and BT8. These lines consistently expressed the Cry1Ab/Ac endotoxin ranging from 0.16 to 0.35 ng/mg of leaf, in the following generations (analyzed upto T4). The effect of Cry1Ab/Ac endotoxin was studied against 3 major Lepidopteran pests of jute- semilooper (Anomis sabulifera Guenee), hairy caterpillar (Spilarctia obliqua Walker) and indigo caterpillar (Spodoptera exigua Hubner) by detached leaf and whole plant insect bioassay on greenhouse-grown transgenic plants. Results confirm that larvae feeding on transgenic plants had lower food consumption, body size, body weight and dry weight of excreta compared to non-transgenic controls. Insect mortality range among transgenic feeders was 66–100% for semilooper and hairy caterpillar and 87.50% for indigo caterpillar. Apart from insect resistance, the transgenic plants were at par with control plants in terms of agronomic parameters and fiber quality. Hence, these Bt jutes in the field would survive Lepidopteran pest infestation, minimize harmful pesticide usage and yield good quality fiber. PMID:29354143

  20. Bt Jute Expressing Fused δ-Endotoxin Cry1Ab/Ac for Resistance to Lepidopteran Pests

    Directory of Open Access Journals (Sweden)

    Shuvobrata Majumder

    2018-01-01

    Full Text Available Jute (Corchorus sp. is naturally occurring, biodegradable, lignocellulosic-long, silky, golden shiny fiber producing plant that has great demands globally. Paper and textile industries are interested in jute because of the easy availability, non-toxicity and high yield of cellulosic biomass produced per acre in cultivation. Jute is the major and most industrially used bast fiber-producing crop in the world and it needs protection from insect pest infestation that decreases its yield and quality. Single locus integration of the synthetically fused cry1Ab/Ac gene of Bacillus thuringiensis (Bt in Corchorus capsularis (JRC 321 by Agrobacterium tumefaciens-mediated shoot tip transformation provided 5 potent Bt jute lines BT1, BT2, BT4, BT7 and BT8. These lines consistently expressed the Cry1Ab/Ac endotoxin ranging from 0.16 to 0.35 ng/mg of leaf, in the following generations (analyzed upto T4. The effect of Cry1Ab/Ac endotoxin was studied against 3 major Lepidopteran pests of jute- semilooper (Anomis sabulifera Guenee, hairy caterpillar (Spilarctia obliqua Walker and indigo caterpillar (Spodoptera exigua Hubner by detached leaf and whole plant insect bioassay on greenhouse-grown transgenic plants. Results confirm that larvae feeding on transgenic plants had lower food consumption, body size, body weight and dry weight of excreta compared to non-transgenic controls. Insect mortality range among transgenic feeders was 66–100% for semilooper and hairy caterpillar and 87.50% for indigo caterpillar. Apart from insect resistance, the transgenic plants were at par with control plants in terms of agronomic parameters and fiber quality. Hence, these Bt jutes in the field would survive Lepidopteran pest infestation, minimize harmful pesticide usage and yield good quality fiber.