Entomology Commons^™

Transcriptional Analysis Of Susceptible And Resistant European Corn Borer Strains And Their Response To Cry1f Protoxin, Neetha Nanoth Vellichirammal, Haichuan Wang, Seong-Il Eyun, Estuko N. Moriyama, Brad Coates, Nicholas Miller, Blair Siegfried

Department of Entomology: Faculty Publications

Background: Despite a number of recent reports of insect resistance to transgenic crops expressing insecticidal toxins from Bacillus thuringiensis (Bt), little is known about the mechanism of resistance to these toxins. The purpose of this study is to identify genes associated with the mechanism of Cry1F toxin resistance in European corn borer (Ostrinia nubilalis Hübner). For this, we compared the global transcriptomic response of laboratory selected resistant and susceptible O. nubilalis strain to Cry1F toxin. We further identified constitutive transcriptional differences between the two strains.

Results: An O. nubilalis midgut transcriptome of 36,125 transcripts was assembled de novo from …

Effect Of Maize Lines On Larval Fitness Costs Of Cry1f Resistance In The European Corn Borer (Lepidoptera: Crambidae), Jennifer L. Petzold-Maxwell, Blair D. Siegfried, Richard L. Hellmich, Craig A. Abel, Brad S. Coates, Terrence A. Spencer, Aaron J. Gassmann

Department of Entomology: Faculty Publications

Crops producing insecticidal toxins from the bacterium Bacillus thuringiensis (Bt) are widely planted and enable management of key insect pests while reducing the use of conventional insecticides. However, the evolution of Bt resistance could diminish these benefits. Fitness costs of Bt resistance occur in the absence of Bt toxin when individuals with resistance alleles show a reduction in fitness relative to susceptible individuals, and they can delay the evolution of resistance. Ecological factors including host-plant variety can affect the magnitude of fitness costs, and consequently, the degree to which fitness costs delay resistance. In this study, we measured fitness costs …

Comparative Susceptibility Of Ostrinia Furnacalis, Ostrinia Nubilalis, And Diatraea Saccharalis (Lepidoptera: Crambidae) To Bacillus Thuringiensis Cry1 Toxins, S. Y. Tan, B. F. Cayabyab, E. P. Alcantara, Y. B. Ibrahim, Fangneng Huang, Erin E. Blankenship, Blair D. Siegfried

Department of Entomology: Faculty Publications

Transgenic corn hybrids that express toxins from Bacillus thuringiensis (Bt) are highly effective against the European corn borer, Ostrinia nubilalis (Hübner), and the closely related Asian corn borer, Ostrinia furnacalis (Guenée). Since the registration of Bt corn hybrids in the U.S. in 1996, there has been a great deal of information generated on O. nubilalis. However, relatively little information exists for O. furnacalis. To help determine whether the information generated for O. nubilalis can be leveraged for decisions regarding the use of transgenic Bt corn against O. furnacalis, experiments were designed to determine whether the pattern of sensitivity …

Inheritance Of Cry1f Resistance In Laboratory-Selected European Corn Borer And Its Survival On Transgenic Corn Expressing The Cry1f Toxin, E. J. G. Pereira, N. P. Storer, Blair D. Siegfried

Department of Entomology: Faculty Publications

A major assumption of the high-dose/refuge strategy proposed for insect resistance management strategies for transgenic crop plants that express toxins from Bacillus thuringiensis is that resistance traits that evolve in pest species will be recessive. The inheritance of Cry1F resistance and larval survival on commercially available Cry1F corn hybrids were determined in a laboratory-selected strain of European corn borer, Ostrinia nubilalis (Hu¨ bner), displaying more than 3000-fold resistance to Cry1F. Concentration-response bioassays of reciprocal parental crosses indicated that the resistance is autosomal and recessive. Bioassays of the backcross of the F₁ generation with the selected strain were consistent with …

Use Of Spectral Vegetation Indices Derived From Airborne Hyperspectral Imagery For Detection Of European Corn Borer Infestation In Iowa Corn Plots, Matthew W. Carroll, John A. Glaser, Richard L. Hellmich, Thomas E. Hunt, Thomas W. Sappington, Dennis Calvin, Ken Copenhaver, Jon Fridgen

Department of Entomology: Faculty Publications

Eleven spectral vegetation indices that emphasize foliar plant pigments were calculated using airborne hyperspectral imagery and evaluated in 2004 and 2005 for their ability to detect experimental plots of corn manually inoculated with Ostrinia nubilalis (Hübner) neonate larvae. Manual inoculations were timed to simulate infestation of corn, Zea mays L., by first and second fiights of adult O. nubilalis. The ability of spectral vegetation indices to detect O. nubilalis-inoculated plots improved as the growing season progressed, with multiple spectral vegetation indices able to identify infested plots in late August and early September. Our findings also indicate that for …

Effects Of The Synergist S,S,S-Tributyl Phosphorotrithioate On Indoxacarb Toxicity And Metabolism In The European Corn Borer, Ostrinia Nubilalis (Hübner), Analiza P. Alves, William J. Allgeier, Blair D. Siegfried

Department of Entomology: Faculty Publications

The toxicity of the oxadiazine insecticide indoxacarb to the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), was evaluated in the presence and absence of S,S,S-tributyl phosphorotrithioate (DEF), an inhibitor of hydrolytic metabolism. Bioassays involving topical application of different concentrations of indoxacarb to third instars of a susceptible O. nubilalis laboratory strain were performed, and in vitro metabolism experiments involving [¹⁴C] indoxacarb were examined to determine the role of hydrolytic metabolism in indoxacarb activation. Indoxacarb toxicity decreased in the presence of DEF indicating antagonism of toxicity. Results of in vivo and in vitro inhibition experiments indicated a …

Inheritance Of Resistance To The Cry1ab Bacillus Thuringiensis Toxin In Ostrinia Nubilalis (Lepidoptera: Crambidae), Analiza P. Alves, Terrence A. Spencer, B.E. Tabashnik, Blair Siegfried

Department of Entomology: Faculty Publications

Laboratory selection with Cry1Ab, the predominant Bacillus thuringiensis (Bt) toxin in transgenic corn, Zea mays L., produced >1000-fold resistance in two laboratory strains of European corn borer, Ostrinia nubilalis (Hubner). We tested the offspring of various crosses to determine the mode of inheritance of resistance to Cry1Ab. Patterns of inheritance of resistance were similar in the two resistant strains. The progeny of reciprocal F₁ crosses (resistant male x susceptible female and vice versa) responded alike in bioassays, indicating autosomal inheritance. The median lethal concentrations (LC₅₀ values) of F₁ were intermediate between the resistant and susceptible parents, indicating …

Effect Of Environment On Resistance To The European Corn Borer (Lepidoptera: Crambidae) In Maize, David B. Willmot, Bruce E. Hibbard, Larry L. Darrah, Linda M. Pollak, Kevin Montgomery, Richard C. Pratt, Craig A. Abel, James A. Hawk, Tecle Weldekidan, John E. Foster

Department of Entomology: Faculty Publications

The European corn borer, Ostrinia nubilalis (Hu¨ bner) (Lepidoptera: Crambidae), is a major pest of maize, Zea mays L., in many temperate parts of the world. Genotype-by-environment interaction effects can make relative performance unpredictable and may hamper selection for resistance to European corn borer. The objective of this study was to determine the effect of environment on genotypic reaction to European corn borer resistance in maize. A set of 12 maize inbred lines was chosen to represent a range of European corn borer responses. Eleven testing environments ranged from Delaware, Ohio, Illinois, Iowa, Nebraska, Missouri, to Mississippi. For length of …

In Vivo And In Vitro Metabolism Of Fi Pronil By Larvae Of The European Corn Borer Ostrinia Nubilalis, Eric W. Durham, Blair D. Siegfried, Michael E. Scharf

Department of Entomology: Faculty Publications

In vivo and in vitro metabolism of [₁₄C]fi pronil was examined in a susceptible European corn borer (Ostrinia nubilalis, Hübner) laboratory strain. [₁₄C]Fipronil penetrated the larval integument slowly, with 71.5% of the applied radioactivity recovered from surface rinses 24 h after topical application. Despite this slow penetration, radioactivity was detected in both the excrement and internal organo-soluble fractions. Radioactivity in the internal aqueous fraction and tissue pellet accounted for less than 0.8% of total radioactivity. The in vivo studies suggest that fipronil oxidation to its sulfone metabolite is the major route of metabolic conversion. …

Chronic Exposure Of The European Corn Borer (Lepidoptera: Crambidae) To Cry1ab Bacillus Thuringiensis Toxin, Josette Chafaux, Maryvonne Seguin, Jeffrey J. Swanson, Denis Bourguet, Blair D. Siegfried

Department of Entomology: Faculty Publications

Transgenic corn expressing the insecticidal toxin from Bacillus thuringiensis Berliner is gaining support as an effective control technology for use against lepidopteran pests, particularly European corn borer, Ostrinia nubilalis Hubner (Lepidoptera: Crambidae). However, there is concern that widespread adoption of transgenic plants will rapidly lead to B. thuringiensis toxin resistance. Thus, long-term selection of O. nubilalis populations with the Cry1Ab B. thuringiensis toxin has been undertaken in several laboratories in the United States and in Europe. We present results from two independent selection experiments performed in laboratories at the University of Nebraska and at the Institut National de la Recherche …

Dispersal Of Adult European Corn Borer (Lepidoptera: Crambidae) Within And Proximal To Irrigated And Non–Irrigated Corn, Thomas E. Hunt, Leon G. Higley, John F. Witkowski, Linda J. Young, Richard L. Hellmich

Department of Entomology: Faculty Publications

The European corn borer, Ostrinia nubilalis (Hübner), causes economic damage to corn, Zea mays L., throughout the Corn Belt. Because this insect has become the primary target of Bacillus thuringiensis Berliner (Bt) transgenic corn, current efforts addressing the management of O. nubilalis resistance to Bt corn require information on adult European corn borer dispersal and factors affecting its dispersal. In 1998 we conducted mark-release-recapture, release-recapture, and caged-mating studies to directly measure and compare local dispersal patterns of O. nubilalis adults within and proximal to irrigated and non-irrigated cornfields. Releases of marked adults were made corresponding to the first and second …

Oviposition By European Corn Borer (Lepidoptera: Crambidae) In Response To Various Transgenic Corn Events, Richard L. Hellmich, L. S. Higgins, John F. Witkowski, J. E. Campbell, L. C. Lewis

Haskell Agricultural Laboratory (Northeast Research and Extension Center)

Oviposition preference by European corn borers, Ostrinia nubilalis (Hübner), for or against transgenic corn would influence amounts of refuge required for resistance management. The objective of this research was to determine if various Bacillus thuringiensis (Bt) corn transgenic events influence O. nubilalis oviposition. All commercially available events (currently 5) were evaluated, plus 1 experimental event. Results from 3 independent studies are reported, including 3 field-cage experiments with vegetative corn, 2 field-cage experiments with reproductive corn, and 2 field experiments with natural O. nubilalis on reproductive corn. In each case, Bt corn hybrids are compared with their near isogenic hybrids by …

Baseline Susceptibility Of European Corn Borer (Lepidoptera: Crambidae) To Bacillus Thuringiensis Toxins, Paula C. R. G. Macron, Linda J. Young, Kevin L. Steffey, Blair Siegfried

Department of Entomology: Faculty Publications

Susceptibility to CrylAb and CrylAc toxins from Bacillus thuringiensis was determined for 11 populations of neonate European corn borer, Ostrinia nubilalis (Hiibner), from the United States and 1 from northern Italy. Corn borer larvae were exposed to artificial diet treated with increasing B. thuringiensis concentrations, and mortality and growth inhibition were evaluated after 7 d. The range of variation in B. thuringiensis susceptibility indicated by growth inhibition was very similar to that indicated by mortality. Although interpopulation variation in susceptibility to both proteins was observed, the magnitude of the differences was small (54-fold) and comparable to the variability observed among …

Seasonal Abundance Of The European Corn Borer Ostrinia Nubilalis (Hbn.) Within The North Central United States, R. E. Hill, H. C. Chiang, A. J. Keaster, W. B. Showers, G. L. Reed

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

Annual changes in corn borer populations in the North Central States were measured as a phase of a Regional Project, NC-20, entitled "Factors Influencing Corn Borer Populations" in Minnesota, Iowa, Kansas, Nebraska, Missouri and Ohio over a period of years. Standardized procedures were followed to estimate the seasonal abundance of the European corn borer, Ostrinia nubilalis (Hbn.), under cropping procedures in different locations within the North Central States. The primary purpose of the present bulletin is to present results for the 1965 to 1969 period and to compare these results with the previous 10 years and thus attempt to analyze …

European Corn Borer, Ostrinia Nubilalis (Hbn.) Populations In Field Corn, Zea Mays (L.) In The North Central United States, R. E. Hill, A. N. Sparks, C. C. Burkhardt, H. C. Chiang, M. L. Fairchild, W. D. Guthrie

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

A long-range study of the annual changes in corn borer populations in the North Central States was started in Minnesota, Iowa, Kansas and Nebraska in 1955 and in Missouri and Ohio in 1956. This investigation was a phase of a broader Regional Project, NC-20, entitled "Factors Influencing Corn Borer Populations" and was undertaken to measure by standardized procedures the seasonal changes in abundance of the European corn borer, Ostrinia nubilalis (Hbn.), under cropping procedures in different locations within, the North Central States. Much valuable information has been accumulated on the abundance and effects of various physical and biotic factors on …