Entomology Commons^™

Study Of Population Dynamics Of Sugarcane Aphid (Melanaphis Sacchari) In Rio Grande Valley, Texas, Neetu Khanal

Theses and Dissertations

Chapter 1: This chapter incorporates detailed information about the biotype concept, aphids, their types and their biotypes, importance of studying insect biotypes and their role in mediating host plant defenses.

Chapter 2: This chapter explains in detail about the biology, biotypes, feeding behavior, damage, and economic loss caused due to sugarcane aphid infestation. This chapter further elaborates on the need for studying population level differences and justifies the objectives and significance of this research study.

Chapter 3: This chapter provides information about the comprehensive work done on three different populations of sugarcane aphid collected from three different locations in Rio …

The Known And Unknowns Of Aphid Biotypes, And Their Role In Mediating Host Plant Defenses, Neetu Khanal, Christopher Vitek, Rupesh R. Kariyat

Biology Faculty Publications and Presentations

Insect species are subjected to disparate selection pressure due to various biotic and abiotic stresses. Management practices including the heavy use of chemical insecticides and introduction of insect-resistant plant cultivars have been found to accelerate these processes. Clearly, natural selection coupled with human intervention have led to insect adaptations that alter phenotypes and genetic structure over time, producing distinct individuals with specialized traits, within the populations, commonly defined as biotypes. Biotypes are commonly found to have better fitness in the new environment and, in the case of aphids, the most commonly studied system for biotypes, have the ability to successfully …

Esterase Mediated Insecticide Resistance In The Southern House Mosquito, Culex Quinquefasciatus, Vivek Pokhrel

LSU Doctoral Dissertations

Much is known about the development of insecticide resistance associated with targeted application against insect populations. However, off-target selection by applications of insecticides in agricultural and residential sites also impacts development of insecticide resistance and is understudied. Similarly, the impact of selecting one life stage of mosquitoes on the insecticide susceptibility of different life stages is largely unknown. The first part of this study shows that susceptibility to chlorantraniliprole, which is applied in rice and sugarcane fields in LA, decreased (5.7 to12-fold) in populations of Culex quinquefasciatus collected from near these fields compared to a reference field strain. In addition, …

Evaluation Of Insecticide Resistance In Populations Of Tobacco Thrips, Frankliniella Fusca (Hinds), And Plant Density Effects On Thrips Injury To Cotton, Jessica L. Krob

Masters Theses

Two field studies were performed in Tennessee to evaluate the effects of plant density and seed spacing on thrips injury to upland cotton (Gossypium hirsutum L.). The plant density study consisted of seeding rate treatments that were low, normal, high, and very high, relative to university Extension recommendations. In the plant spacing study, treatments were implemented using nearly identical seeding rates but with relatively uniform seed spacing versus a clumped, “hill-dropped” spacing. In both studies, the seed was either treated with an insecticide (imidacloprid) and a fungicide or only with a fungicide. Due to variable environmental conditions, the results …

Horn Fly (Diptera: Muscidae) - Biology, Management, And Future Research Directions, Gary Brewer, Dave J. Boxler, Luisa D. Domingues, Rebecca T. Trout Fryxell, Chris Holderman, Kelly M. Loftin, Erika Machtinger, Brandon Smythe, Justin L. Talley, Wes Watson

Department of Entomology: Faculty Publications

The horn fly, Haematobia irritans irritans (L.), is one of the most important external parasites of cattle in North America and elsewhere. Horn fly adults have an intimate association with cattle, their primary host. With their often-high numbers and by feeding up to 38 times per day per fly, horn flies stress cattle. The resulting productivity loss is valued at more than 2.3 billion USD in the United States. Insecticides are commonly used to mitigate direct injury from feeding and indirect injury from disease transmission. This paper discusses horn fly biology, distribution, and management. Emphasis is on promising new approaches …

Insecticide Resistance Management Approaches And Naturally Derived Toxicants For The Control Of Fall Armyworm, Spodoptera Frugiperda, Sarah Mccomic

LSU Master's Theses

Spodoptera frugiperda, the fall armyworm (FAW), is a major agricultural pest causing billions of dollars in damage annually to staple crops. Agricultural losses stemming from this pest continues to increase as resistance to commercialized insecticide classes evolves and spreads. Considering this, novel chemistries with new modes of action as well as novel resistance management strategies need to be developed to achieve continued control of FAW populations. This project consisted of two main goals. First, we aimed to develop a neurophysiological assay to enable a more precise understanding of pyrethroid and organophosphate resistance at the level of the nerve. We …

Helicoverpa Zea (Boddie) (Lepidoptera: Noctuidae) Larval Distribution On Different Bt Technologies And Evaluating Cotton Plant Tissue Assays For Resistance Monitoring, Dawson David Kerns

Masters Theses

Field trials were conducted in 2018 at the West Tennessee Research and Education Center (WTREC) in Jackson, TN and in 2019 at locations in College Station, TX, Tillar, AR, and Jackson, TN. Non-Bt, Cry1Ac + Cry1F, and Cry1Ac + Cry2Ab cotton varieties were either treated with an insecticide or left untreated. After five days, cotton plants were mapped for signs of bollworm, Helicoverpa zea (Lepidoptera: Noctuidae), feeding on floral structures (i.e., bolls, squares, flowers) and the physical presence of larvae. Bt technologies reduced the number of H. zea larvae and the amount of feeding injury, but no major differences in …

Geographic Distribution Of Bacillus Thuringiensis Cry1f Toxin Resistance In Western Bean Cutworm (Lepidoptera: Noctuidae) Populations In The United States, Brad S. Coates, Craig A. Abel, Katharine A. Swoboda-Bhattarai, Debra E. Palmquist, Débora Goulart Montezano, Sarah N. Zukoff, Yangzhou Wang, Jeffery D. Bradshaw, Christina D. Difonzo, Elson Shields, Kelley J. Tilmon, Thomas Hunt, Julie A. Peterson

West Central Research and Extension Center, North Platte

The western bean cutworm (WBC), Striacosta albicosta (Lepidoptera: Noctuidae), can be a severe pest of transgenic corn in the western Plains and Great Lakes regions of North America, including on hybrids expressing the Bacillus thuringiensis (Bt) Cry1F toxin. The level and geographic distribution of Cry1F resistance are not completely known. Neonate S. albicosta from 10 locations between Nebraska and New York state were subjected to dose–response trypsin-activated native Cry1F toxin overlay bioassays. In 2017, the mean estimated lethal concentration causing 50% larval mortality (LC50) ranged from 15.1 to 18.4 μg Cry1F cm−2, and were not significantly different among locations. In …

The Evolution Of Spinosad Resistance In Colorado Potato Beetles (Leptinotarsa Decemlineata), Coby Michael Klein

Dissertations, Theses, and Capstone Projects

Colorado potato beetles (Leptinotarsa decemlineata) are a major pest of cultivated potato plants worldwide. They are well-known for their ability to rapidly evolve resistance to all major classes of pesticides. Defoliation of potato plants by L. decemlineata can reduce potato yields by a considerable margin. The damage done by resistant beetles is steep and much research is focused on developing new chemical controls, especially those derived from naturally occurring compounds. Spinosad is a relatively new natural product insecticide, introduced approximately a decade ago, suitable for use in organic farming. Potato beetles on Long Island, NY developed very strong …

Advances In Molecular Research On Bed Bugs (Hemiptera: Cimicidae), Sanjay Basnet, Shripat T. Kamble

Department of Entomology: Faculty Publications

With the resurgence and increase in infestations of the common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), across the world, there has been renewed interest in molecular research on this pest. In this paper, we present current information on the biology, medical importance, management practices, behavior and physiology, and molecular research conducted on bed bugs. The majority of molecular studies are focused towards understanding the molecular mechanism of insecticide resistance. Bed bugs are hematophagous insects with no prior record of vectoring any disease organisms. An improved understanding of how bed bugs lack vector competency may provide information to prevent disease …

Double-Stranded Rna Binding Protein, Staufen, Is Required For The Initiation Of Rnai In Coleopteran Insects, June-Sun Yoon, Kanakachari Mogilicherla, Dhandapani Gurusamy, Xien Chen, Shankar C. R. R. Chereddy, Subba R. Palli

Entomology Faculty Publications

RNA interference (RNAi) is being used to develop methods to control pests and disease vectors. RNAi is robust and systemic in coleopteran insects but is quite variable in other insects. The determinants of efficient RNAi in coleopterans, as well as its potential mechanisms of resistance, are not known. RNAi screen identified a double-stranded RNA binding protein (StaufenC) as a major player in RNAi. StaufenC homologs have been identified in only coleopteran insects. Experiments in two coleopteran insects, Leptinotarsa decemlineata and Tribolium castaneum, showed the requirement of StaufenC for RNAi, especially for processing of double-stranded RNA (dsRNA) to small interfering …

The Mechanism Of Rna Interference In Arthropods, June-Sun Yoon

Theses and Dissertations--Entomology

RNA interference (RNAi) is a useful reverse genetics tool for investigation of gene function as well as for practical applications in many fields including medicine and agriculture. Due to the variability in RNAi efficiency, RNAi-based methods are currently being developed for controlling only coleopteran insects which are known to be amenable to RNAi. The first chapter of my thesis includes findings from research to investigate what are the factors that make coleopteran insects relatively more efficient in RNAi. I used Colorado potato beetle (CPB), Leptinotarsa decemlineata and its cell line (Lepd-SL1) as study models to identify genes that play key …

Fitness Costs And Inheritance Of Bt Cry2ab2 Resistance In Fall Armyworm, Spodoptera Frugiperda (J.E. Smith), Binod Acharya

LSU Master's Theses

Evolution of resistance in target pest populations is a major threat to the sustainability of transgenic crops expressing Bacillus thuringiensis (Bt) proteins. Fall armyworm, Spodoptera frugiperda (J.E. Smith), is a cross-crop target pest of Bt corn, Bt cotton, and Bt soybean. This pest, thus far, is the only target pest species that has developed field resistance to Bt crops in multiple areas across countries. Cry2Ab2 is a common Bt protein expressed in transgenic corn and cotton targeting lepidopteran pests including S. frugiperda. The objective of this study was to characterize fitness costs and inheritance of Cry2Ab2 resistance in S. frugiperda. …

Towards The Development Of Ash Varieties Resistant To Emerald Ash Borer, Lindsay Ann Kolich

Open Access Theses

The emerald ash borer (EAB; Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae) is a destructive invasive beetle from Asia which has killed millions of ash trees (Fraxinus spp.) throughout North America. This phloem-feeding borer is capable of killing otherwise healthy trees and colonizes trees as small as saplings - most affected trees die within four years of colonization. Asian ash species (i.e., Manchurian and Chinese) appear to be more resistant to EAB than those native to North America (e.g., green, white, and black ash). In this project we use reciprocal and conspecific grafts of these five ash species to determine the …

Resistance Of Fall Armyworm, Spodoptera Frugiperda (J.E. Smith) To Bacillus Thuringiensis, Ying Niu

LSU Master's Theses

The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a target pest of Bacillus thuringiensis (Bt) corn in North and South America. In this study, multiple tests were conducted in the laboratory and greenhouse to 1) determine the susceptibility of two field populations of S. frugiperda collected from Florida (FL) and Puerto Rico (PR) to purified Cry1F protein and Bt corn leaf tissue and 2) evaluate larval survival of and plant injury by Cry1F-susceptible, -resistant, and –heterozygous genotypes of S. frugiperda on whole plants of transgenic corn containing single and pyramided Bt genes. Corn hybrids evaluated in this study included five …

Kinematic Analysis Of Axial Rotations And The Effects Of Stress Selection On Takeoff Flight Performance, Michael L. Brewer

UNLV Theses, Dissertations, Professional Papers, and Capstones

The importance of flying insects cannot be understated; without them as pollinators, the great diversity of flowing plants could not have occurred. Flight requires a suite of highly derived morphological and physiological characteristics that may limit the evolutionary responses of other life history traits.

To investigate the complexities of maneuvering flight, I used high-speed videography to analyze wing and body motions in the HoverflySyritta pipiens(Order: Diptera) during horizontal turns called saccades. I characterized the saccades by calculating the instantaneous rotational velocities throughout the saccade, maximum rotational velocity, and the mean rotational velocity. I then compared the shape of the rotational …

Characterization Of Resistance To The Cry1f Toxin From Bacillus Thuringiensis In Resistant Fall Armyworm, Spodoptera Frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) From Puerto Rico, Ana Maria Velez

Department of Entomology: Dissertations, Theses, and Student Research

Transgenic corn expressing Cry1F protein from Bacillus thuringiensis Berliner has been registered for Spodoptera frugiperda control since 2003. Unexpected damage to Cry1F corn was reported in 2006 in Puerto Rico and Cry1F resistance in S. frugiperda was documented. The inheritance of Cry1F resistance was characterized in a S. frugiperda resistant strain from Puerto Rico which displayed >387-fold resistance to Cry1F. Concentration-response bioassays of reciprocal crosses of resistant and susceptible parental populations indicated that resistance is recessive and autosomal. Bioassays of the backcross of the F₁ generation crossed with the resistant parental strain suggest that a single locus is responsible …

Inheritance Of Cry1f Resistance, Crossresistance And Frequency Of Resistant Alleles In Spodoptera Frugiperda (Lepidoptera: Noctuidae), A. M. Vélez, T. A. Spencer, A. P. Alves, D. Moellenbeck, R. L. Meagher, H. Chirakkal, B. D. Siegfried

Department of Entomology: Faculty Publications

Transgenic maize, Zea maize L., expressing the Cry1F protein from Bacillus thuringiensis has been registered for Spodoptera frugiperda ( J. E. Smith) control since 2003. Unexpected damage to Cry1F maize was reported in 2006 in Puerto Rico and Cry1F resistance in S. frugiperda was documented. The inheritance of Cry1F resistance was characterized in a S. frugiperda resistant strain originating from Puerto Rico, which displayed >289-fold resistance to purified Cry1F. Concentration–response bioassays of reciprocal crosses of resistant and susceptible parental populations indicated that resistance is recessive and autosomal. Bioassays of the backcross of the F1 generation crossed with the resistant parental …

Investigating The Tolerance Response Of Early Vegetative Stage Soybeans To Aphis Glycines Matsumura, Lia Da Silva Marchi

Department of Entomology: Dissertations, Theses, and Student Research

The objectives of this research were to evaluate the impact of soybean aphid (Aphis glycines Matsumura) feeding on the yield response of V1, V3, and R1 KS4202 soybean plants and examine the effect of soybean aphid feeding on peroxidase activity in V1 and V3 KS4202 plants. KS4202 plants infested during the early vegetative stages (VC, VE and V1) were identified as highly susceptible based upon plant damage and stunting of the plants. In contrast, V3, V4, and V5 stage KS4202 soybeans were classified as moderately resistant. In the yield response study, V1, V3 and R1 plants had aphid numbers …

Crop Updates 2011 - Pests And Diseases, Jeff Russell, Paul Umina, Svetlana Micic, Laura Fagan, Mark Seynour, Tony Dore, Pam Burgess, John Majewski, Manisha Shankar, Rob Loughman

Crop Updates

This session covers four papers from different authors:

1. Grains biosecurity – everyone’s business, Jeff Russell, Department of Agriculture and Food

2. Control of insect and mite pests in grains – insecticide resistance and integrated pest management (IPM), Paul Umina¹, Svetlana Micic² and Laura Fagan³, ¹CESAR and The University of Melbourne, ²Department of Agriculture and Food, ³University of Western Australia

3. Effect of cropping rotations on pest mites of broadacre agriculture, Svetlana Micic, Mark Seymour, Tony Dore and Pam Burgess, Department of Agriculture and Food

4. Common bunt resistance in …

A Study Of Horn Fly, Haematobia Irritans (L.) (Diptera: Muscidae), Target-Site Sensitivity, Susceptibility, And Resistance Management At Selected Sites In Louisiana, Cole David Younger

LSU Doctoral Dissertations

The purpose of the first study was to evaluate the effectiveness of the use of a mid-season avermectin pour-on to cattle for managing OP resistance in horn fly populations at the Rosepine Louisiana Agricultural Research Station. During an eight year study, ivermectin treatments were made three times (when the treatment threshold of less than five weeks of control was reached), and in the following years, the number of weeks of control increased to 9 to 10 weeks each time. The purpose of the second study was to test a two-year OP/one-year pyrethroid rotation strategy as a strategy for maintaining susceptibility …

Association Of Esterases In Resistance To Naled And Resmethrin In The Southern House Mosquito, Culex Quinquefasciatus, Jennifer R. Gordon

LSU Master's Theses

The vector-competency and its affinity for humans make C. quinquefasciatus an important target of mosquito abatement programs. Whenever such control programs are implemented, protocols to monitor frequencies and mechanisms of resistance to the insecticides used are necessary to optimize the efficacy of the management strategy and to slow development of resistance to the insecticides used. In the current study, susceptibilities to the two adulticides used by EBRMARC (naled and resmethrin) were monitored using field-collected mosquitoes and a topical and contact bioassay, respectively. My hypothesis was that esterase-mediated enhanced metabolism conferred resistance to both insecticides in populations of C. quinquefasciatus from …

Ducking As The Means Of Resistance In "Candy-Cane" Stems Of Goldenrod: Straightened Stems Lose Their Edge, M. J. Wise, W. G. Abrahamson, J. A. Cole

Warren G. Abrahamson, II

Herbivores are among the most pervasive selective forces acting on plants, and the number of plant chemicals that presumably evolved for defense against herbivory is immense. In contrast, biologists are only beginning to appreciate the important roles that architectural traits can play in antiherbivore defense. One putative architectural-resistance trait is the nodding stem apex of some goldenrods (Solidago ; Asteraceae). Individuals of S. altissima genets that undergo temporary nodding in the late spring (i.e., “candy-cane ramets) have been shown to be more resistant than individuals of erect-stemmed genets to certain apex-attacking” herbivores. We tested the hypothesis that the greater resistance …

Crop Updates 2009 - Cereals, Jeff Baldock, Doug Edmeades, Mark Seymour, Paul Carmody, Ian Pritchard, Alan Meldrum, Michael Robertson, Roger Lawes, Rob Sands, Peter White, Felicity Byrne, Andrew Bathgate, Kedar Adhikari, Tanveer Khan, Stuart Morgan, Alan Harris, P. Gaur, K. M. H. Siddique, H. Clarke, N. C. Turner, W. Macleod, S. Morgan, Chris Veitch, Tony Leonforte, Kith Jayasena, Geoff Thomas, Rob Loughman, Kazue Tanaka, Ravjit Khangura, M. Amjad, Richard Oliver, Dusty Severtson, Peter Mangano, John Botha, Brenda Coutts, Manisha Shankar, Kasia Rybak, Michael Baker, Andrea Hills, Shahajahan Miyan, Peter Portmann, Nicole Rice, Robert Henry, Jeff J. Russell, B. H. Paynter, Linda Price, Brenda Shackley, Vicki Scanlan, Darshan Sharma, Christine Zaicou-Kunesch

Crop Updates

This session covers twenty seven papers from different authors:

PLENARY

1. Building soil carbon for productivity and implications for carbon accounting, Jeff Baldock, CSIRO Land and Water, Adelaide, SA

2. Fact or Fiction: Who is telling the truth and how to tell the difference, Doug Edmeades, agKnowledge Ltd, Hamilton

3. Four decades of crop sequence trials in Western Australia, Mark Seymour,Department of Agriculture and Food

BREAK CROPS

4. 2008 Break Crops survey Report, Paul Carmody,Development Officer, Department of Agriculture and Food

5. Attitudes of Western Australian wheatbelt growers to ‘Break Crops’, Paul Carmody and Ian …

Crop Updates 2008 - Lupins, Pulses And Oilseeds, Mark Seymour, Robert Johnson, Ian Pritchard, Raj Malik, Wayne Parker, Martin Harries, Bob French, Jo Walker, Laurie Maiolo, Leigh Smith, Alan Harris, Rod Hunter, Tanveer Khan, Jenny Garlinge, Pooran Gaur, Kambot Siddique, Heather Clarke, Neil Turner, William Macleod, Stuart Morgan, Wendy Vance, Philip Chambers, Chris Veitch, Tony Leonforte, Rodger Beermier, Moin Salam, Jenny Davidson, Jean Galloway, Pip Payne, Tess Humphries, Art Diggle, Harmohinder Dhammu, Michael Materne, Kerry Regan, Mohammad Amjad, Andy Sutherland, Pat Fels, Glen Riethmuller, Wallace Cowling, Milton Saunders, Eliot Jones, Chris Newman, John Duff, David Sermon, Svetlana Micic, Anthony Dore, Geoff Strickland, Blakely Paynter, Vince Lambert, Chris Roberts

Crop Updates

This session covers twenty six papers from different authors:

Regional Roundup

1. SOUTH EAST AGRICULTURAL REGION, Mark Seymour Department of Agriculture and Food, and Robert Johnson CBH Group, Esperance

2. CENTRAL AGRICULTURAL REGION, Ian Pritchard, Department of Agriculture and Food

3. GREAT SOUTHERN AND LAKES REGION, Raj Malik, Department of Agriculture and Food

4. NORTHERN AGRICULTURAL REGION, Wayne Parker and Martin Harries, Department of Agriculture and Food

LUPINS

5. Cropping lupins in wide rows in Western Australia, Martin Harries and Bob French, Department of Agriculture and Food

6. The effect of sowing time and radish density …

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 …

High-Level Resistance To Bacillus Thuringiensis Toxin Cry1ac And Cadherin Genotype In Pink Bollworm, Aaron J. Gassmann, Robert W. Biggs, Jeffrey A. Fabrick, Bruce E. Tabashnick, Timothy J. Dennehy, Yves Carriere, Shai Morin

Aaron J. Gassmann

Resistance to transgenic cotton, Gossypium hirsutum L., producing Bacillus thuringiensis (Bt) toxin Cry1Ac is linked with three recessive alleles of a cadherin gene in laboratory-selected strains of pink bollworm, Pectinophora gossypiella (Saunders), a major cotton pest. Here, we analyzed a strain (MOV97-R) with a high frequency of cadherin resistance alleles, a high frequency of resistance to 10 μg of Cry1Ac per milliliter of diet, and an intermediate frequency of resistance to 1,000 μg of Cry1Ac per ml of diet. We selected two strains for increased resistance by exposing larvae from MOV97-R to diet with 1,000 μg of Cry1Ac per ml …

Xenobiotic Response In Drosophila Melanogaster: Sex Dependence Of P450 And Gst Gene Induction, Gaelle Le Goff, Frederique Hilliou, Blair Siegfried, Sam Boundy, Eric Wajnberg, Luc Sofer, Pascaline Audant, Richard H. Ffrench-Constant, Rene Feyereisen

Department of Entomology: Faculty Publications

The effect of xenobiotics (phenobarbital and atrazine) on the expression of Drosophila melanogaster CYP genes encoding cytochromes P450, a gene family generally associated with detoxification, was analyzed by DNA microarray hybridization and verified by real-time RT-PCR in adults of both sexes. Only a small subset of the 86 CYP genes was significantly induced by the xenobiotics. Eleven CYP genes and three glutathione S-transferases (GST) genes were significantly induced by phenobarbital, seven CYP and one GST gene were induced by atrazine. Cyp6d5, Cyp6w1, Cyp12d1 and the ecdysone-inducible Cyp6a2 were induced by both chemicals. The constitutive expression of several of the inducible …

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 …

Genetic Analysis Of Resistance To European Corn Borer (Ostrinia Nubllalls Hub. Lepidoptera:Crambidae) Damage In Eight Maize Germplasm, Cengis Ikten, John E. Foster

Department of Entomology: Faculty Publications

The inheritance of resistance to Oslrinia nubilalis (ECB) damage in eight breeding maize lines was studied by Griffing's diallel analysis (Griffing 1956) under two water regimes. One hundred fifty neonate larvae of second generation of ECB were infested around ear node of maize germplasm and approximately two months later, the potentials of the germplasm were determined by measuring stalk and shank tunneling damage in plants. General combining ability (GCA) was more important than specific combining ability (SCA) in determining resistance to both stalk and shank tunneling. Although mean squares for GCA accounted for 76.1% of the variation for stalk tunneling …