Entomology Commons^™

A Comparative Study Of Medicago Truncatula Transcriptomes As They Relate To Saponin Defenses Against Insect Pests, Audra Mae Rogers

Graduate Theses and Dissertations

Triterpene saponins are a class of defensive plant-derived compounds, which have a

variety of functions including antimicrobial, insecticidal, and nematicidal activities. This

research assessed the performance of the beet armyworm, Spodoptera exigua, following ad

libero feeding on Medicago truncatula accessions differing in specialized metabolite and

saponin profiles. Insect performance did not directly relate to the foliar saponin levels in the

accessions, which was measured using HPLC mass spectrometry. Accession ESP105 had the lowest foliar saponins overall, yet had similar levels of soyasaponins compared to the other accessions. Conversely, accessions A17, PRT178, and GRC43 had high foliar saponins with particularly high …

Cost: Benefit Analysis Of Insect Net Use In Cabbage In Real Farming Conditions Among Smallholder Farmers In Benin, Faustin Vidogbéna, Anselme Adégbidi, Françoise Assogba-Komlan, Thibaud Martin, Mathieu Ngouajio, Serge Simon, Rigobert Tossou, Laurent Parrot

All Peer-Reviewed Publications

Insect net use provides a physical exclusion of pests as well as a microclimate change, thus increasing soil humidity, vegetable quality and yields in tropical conditions. This paper presents the findings of a cost:benefit analysis of this technology in real farming conditions compared to current insecticide practices. The surveys were conducted in Benin for cabbage production (. Brassica oleracea L.) during two production cycles. There were almost no significant differences in costs between unnetted and netted cabbage for the two production cycles. The only factors that varied were farm gate prices, the number of cabbages marketed and their size. Improved …

Stink Bugs: Spatial Distribution, Pecan Phenological Susceptibility And Sampling Program, Brian Cowell

Graduate Theses and Dissertations

An effective management program for stink bugs (SBs) in pecan groves requires knowledge of: stages of the pecans susceptible to SB damage; strata of the tree with SB damaged nuts; a practical SB monitoring method; and, effects of landscapes contributing SBs into pecan groves.

Stink bugs produced feeding punctures in pecan shucks at all phenological stages. Pecans punctured before the dough stage drop from the tree. Kernel damage occurs in the pecans’ dough stage, whereas mature pecans are not damaged.

The pecans collected from the whole tree using the tree shaker had significantly less punctures than the pecans collected from …

Canola: A Modern Crop For A Modern Era, Kenneth J. Roché

Doctor of Plant Health Program: Dissertations and Student Research

The University of Nebraska-Lincoln Doctor of Plant Health program is a professional doctorate program with a comprehensive approach to plants and agriculture. The program emphasizes a broad interdisciplinary education across all plant-related disciplines, practical learning, research, and experience through internships. For my final required internship, I worked as a senior agricultural research intern with Research Designed for Agriculture (RD4AG) in Montana. RD4AG is a contract research organization based in Yuma, AZ with over thirty-years of experience. During my three month internship at RD4AG in Montana, a large portion of my responsibilities centered on managing regulated canola trials that were undertaken …

Evidence Of Field-Evolved Resistance To Bifenthrin In Western Corn Rootworm (Diabrotica Virgifera Virgifera Leconte) Populations In Western Nebraska And Kansas, Adriano E. Pereira, Haichuan Wang, Sarah N. Zukoff, Lance Meinke, B. Wade French, Blair Siegfried

Department of Entomology: Faculty Publications

Pyrethroid insecticides have been used to control larvae or adults of the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, a key pest of field corn in the United States. In response to reports of reduced efficacy of pyrethroids in WCR management programs in southwestern areas of Nebraska and Kansas the present research was designed to establish a baseline of susceptibility to the pyrethroid insecticide, bifenthrin, using susceptible laboratory populations and to compare this baseline with susceptibility of field populations. Concentration-response bioassays were performed to estimate the baseline susceptibility. From the baseline data, a diagnostic concentration (LC99) was determined and …

Nebline, November/December 2015

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Feature: Chill Out Over the Holidays by Freezing Foods Ahead

Food & Health

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Effects Of Agroforestry On Pest, Disease And Weed Control: A Meta-Analysis, Lorena Pumariño, Gudeta Weldesemayat Sileshi, Sofia Gripenberg, Riikka Kaartinen, Edmundo Barrios, Mary Nyawira Muchane, Charles Midega, Mattias Jonsson

All Peer-Reviewed Publications

Agroforestry practices may influence pest incidence and abundance both through increased top-down regulation by natural enemies and via bottom-up factors such as moderation of microclimate, soil nutrients and water content. We conducted a meta-analysis of the effects of agroforestry on the abundance of invertebrate pests, weeds, natural enemies and plant damage due to pests and diseases. We also tested whether effects of agroforestry were dependent on crop type (annual or perennial), type of pest association (above or belowground) and weed type (parasitic Striga weeds or non-parasitic weeds).Agroforestry practices resulted in lower abundances of both parasitic and non-parasitic weeds, and in …

Nebline, October 2015

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Feature: We All Benefit From Pollinator Habitats

Food & Health

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Nebline, September 2015

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Feature: 4-H Youth “Let the Good Times Grow” at Super Fair

Food & Health

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Sternal Gland Structures In Males Of Bean Flower Thrips, Megalurothrips Sjostedti, And Poinsettia Thrips, Echinothrips Americanus, In Comparison With Those Of Western Flower Thrips, Frankliniella Occidentalis (Thysanoptera: Thripidae), Stephanie Krueger, Sevgan Subramanian, Saliou Niassy, Gerald B. Moritz

All Peer-Reviewed Publications

Sternal pores are important features for identification of male thrips, especially within the subfamily Thripinae. They vary in shape, size and distribution even between species of one genus. Their functional role is speculated to be that of sex- and/or aggregation pheromone production. Yet, sexual aggregations are not reported in Echinothrips americanus, known to have sternal pores, while we observed aggregations in Megalurothrips sjostedti, previously reported to lack them. We examined the sternal glands and pores of the thripine species E. americanus and M. sjostedti males, in comparison with those of Frankliniella occidentalis using light microscopy, as well as scanning and …

Nebline, August 2015

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Feature: Nutrition Education Program Reaches 15-Year-Milestone Teaching Nutrition in Lincoln Schools

Food & Health

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Special pullout section: Lancaster County Super Fair 2015 Schedule & Map

Biochemical, Physiological, And Anatomical Insights Into Aphid-Bioenergy Switchgrass Interactions, Travis J. Prochaska

Department of Entomology: Dissertations, Theses, and Student Research

Switchgrass, Panicum virgatum L., a perennial, warm-season grass native to North America, is a candidate for development as a bioenergy crop. Previously, warm-season grasses were considered to be relatively pest free in their native habitats. However, recent studies using the hemipteran family Aphididae have shown phloem-feeding insects can lead to significant injury in switchgrass. The objectives of this research were to: 1) gain physiological, biochemical, and anatomical insights into insect-bioenergy switchgrass interactions to determine potential insect resistance mechanisms among susceptible and resistant switchgrass genotypes; and 2) to generate and evaluate diverse segregating populations of switchgrass, both resistant and susceptible, to …

Nebline, July 2015

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Feature: Reduce Bullying and Cyberbullying Through Social and Emotional Learning

Food & Health

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Grower Adoption Of An Integrated Pest Management Package For Management Of Mango-Infesting Fruit Flies (Diptera: Tephritidae) In Embu, Kenya, J. K. Korir, H. D. Affognon, C. N. Ritho, W. S. Kingori, P. Irungu, S. A. Mohamed, S. Ekesi

All Peer-Reviewed Publications

Mango (Mangifera indica L.) is a well-recognized fruit of economic and nutritional importance to smallholder farmers across Africa. Production and marketing of this fruit is, however, severely hampered by fruit fly infestation that is responsible for enormous fruit losses. In Kenya, control of this pest is primarily dependent on the use of chemical pesticides, a strategy that has been shown to be ineffective. Although the recently introduced fruit fly integrated pest management (IPM) package developed by the International Centre of Insect Physiology and Ecology (icipe) has proved to be effective against this pest, there is little demonstrable investigation on its …

Predicting The Impact Of Temperature Change On The Future Distribution Of Maize Stem Borers And Their Natural Enemies Along East African Mountain Gradients Using Phenology Models, Sizah Mwalusepo, Henri E.Z. Tonnang, Estomih S. Massawe, Gerphas O. Okuku, Nancy Khadioli, Tino Johansson, Paul André Calatayud, Bruno Pierre Le Ru

All Peer-Reviewed Publications

Lepidopteran stem borers are among the most important pests of maize in East Africa. The objective of the present study was to predict the impact of temperature change on the distribution and abundance of the crambid Chilo partellus, the noctuid Busseola fusca, and their larval parasitoids Cotesia flavipes and Cotesia sesamiae at local scale along Kilimanjaro and Taita Hills gradients in Tanzania and Kenya, respectively. Temperature-dependent phenology models of pests and parasitoids were used in a geographic information system for mapping. The three risk indices namely establishment, generation, and activity indices were computed using current temperature data record from local …

Flowers In Space Attacked By Aliens: Understanding The Spatial Ecology Behind The Devastating Damage By A Thistle Bud Weevil On Pitcher’S Thistle At Whitefish Dunes State Park, Wi, Zechariah D. Meunier

Lawrence University Honors Projects

One of the most threatened plants in the Great Lakes region is Pitcher’s thistle (Cirsium pitcheri), which inhabits sand dunes along the shorelines of Lakes Michigan, Huron, and Superior. In addition to risks from habitat loss and invasive species, C. pitcheri are imperiled by a thistle bud weevil (Larinus planus) that was originally distributed for biological control of nonnative thistles. During the summer of 2014, we empirically studied the devastating damage caused by L. planus on a population of C. pitcheri at Whitefish Dunes State Park, WI, to determine what factors influence the distribution and intensity …

Nebline, June 2015

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Feature: After-Harvest Care Of Asparagus

Food & Health

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Horticulture

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Determinants Of Adoption Of Climate-Smart Push-Pull Technology For Enhanced Food Security Through Integrated Pest Management In Eastern Africa, A. W. Murage, C. A.O. Midega, J. O. Pittchar, J. A. Pickett, Z. R. Khan

All Peer-Reviewed Publications

Food security attainment in Africa has been hindered by poor yields of cereals that serve both as staple and cash crops for the majority of smallholder farmers. Among the various constraints responsible for lower yields are the parasitic weed Striga, and Stemborer pests whose control has remained a challenge. The International Centre of Insect Physiology and Ecology (icipe) with partners developed a novel conservation agricultural technology termed ‘push-pull’, based on companion cropping that effectively controls both constraints simultaneously. However, the effects of climate change threatened its expansion into drier areas where Striga is rapidly spreading. Further adaptation of the conventional …

Comparative Analysis Of Pesticide Effects On Natural Enemies In Western Orchards: A Synthesis Of Laboratory Bioassay Data, Nicholas J. Mills, Elizabeth H. Beers, Peter W. Shearer, Thomas R. Unruh, Kaushalya G. Amarasekare

Agricultural and Environmental Sciences Faculty Research

Pesticides are commonly used for pest management in apple, pear and walnut orchards in the western U.S. and may disrupt biological control of secondary pests in these crops. A comparative analysis was made of results obtained from a series of laboratory bioassays of acute mortality and life table response experiments to estimate lethal and sublethal effects of eight pesticides on seven natural enemy species through use of stage-structured population models. Even though a number of the pesticides tested were reduced-risk products, all of them with the exception of copper plus mancozeb and chlorantraniliprole, caused more than 80% acute mortality of …

Nebline, May 2015

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Feature: It is Important for Youth to Keep Learning and Stay Active During Summer

Food & Health

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Assessment Of Variation In Susceptibility Of The Fall Armyworm, Spodoptera Frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), To Bacillus Thuringiensis Toxins, Karen Ferreira Da Silva

Department of Entomology: Dissertations, Theses, and Student Research

The fall armyworm, Spodoptera frugiperda, is a polyphagous insect pest affecting multiple crops. Fall armyworm is managed with insecticides and corn hybrids expressing insecticidal proteins derived from Bacillus thuringiensis. The early detection of insect resistance is important for making appropriate management decisions informs IPM and IRM recommendations.

The objective of the first study was to establish baseline susceptibility of fall armyworm populations to the Cry1F Bt insecticidal protein, emphasizing collections from locations where fall armyworm overwinters in the U.S. Fall armyworm neonates were exposed to artificial diet treated with increasing Cry1F concentrations, and mortality and growth inhibition were …

Seasonal Activity And Sampling Methods For The Dectes Stem Borer, Dectes Texanus Leconte, In Nebraska Soybeans, Zachary D. Rystrom

Department of Entomology: Dissertations, Theses, and Student Research

The Dectes stem borer, Dectes texanus Leconte, has caused significant economic damage to soybean fields in south central Nebraska during recent years. Most economic injury occurs when soybean plants become susceptible to late season lodging due to larval girdling. Developing a comprehensive management plan for Dectes stem borer in Nebraska is limited by lack of knowledge of seasonal activity and effective sampling plans to monitor adult populations. Field studies were conducted in 2013 and 2014 to describe Dectes stem borer adult emergence patterns, female ovipositional period and adult densities in soybean fields. Calendar date predictions for adult emergence varied, while …

Producing Quality Barley For The Malting Industry, Haley H. Oser Dph

Doctor of Plant Health Program: Dissertations and Student Research

The University of Nebraska – Lincoln Doctor of Plant Health program requires each student to fulfill a professional internship over the last summer of the program. For my internship, I worked as a Barley Scientist Intern for MillerCoors and Golden Malting in Golden, Colorado. During this internship I gained a fundamental understanding of malting barley production with a significant emphasis on grain quality. Barley produced for malting must fulfill strict industry quality standards before it is accepted by the head maltsters. These quality standards include: a high germination rate, low moisture content, protein content within an acceptable range and the …

Nebline, April 2015

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Feature: 4-H Clubs of Excellence Award Recognizes Successful Clubs

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Special Pullout Section: Weed Awareness

Eco-Evolutionary Factors Drive Herbivore-Induced Plant Volatiles, Which Intercept Plant Defense, Elizabeth K. Rowen

Open Access Theses

Herbivore-induced plant volatiles (HIPVs) mediate a wide variety of interactions in ecosystems. However, many volatile compounds are found across plant taxa, and some are exploited to attract natural enemies for biological control. Subtle changes in HIPV blends can produce profound changes in the behavior of predators, parasitoids and herbivores, and may also alter the defensive processes of neighboring plants. I investigated different ecological and evolutionary factors to understand how plant volatile emissions are affected by feeding guild, herbivore diet breadth and domestication. I meta-analyzed 109 studies and found that specialists induce more total volatiles than generalists. Domesticated species have stronger …

Responses Of Parasitoids To Volatiles Induced By Chilo Partellus Oviposition On Teosinte, A Wild Ancestor Of Maize, Daniel M. Mutyambai, Toby J.A. Bruce, Charles A.O. Midega, Christine M. Woodcock, John C. Caulfield, Johnnie Van Den Berg, John A. Pickett, Zeyaur R. Khan

All Peer-Reviewed Publications

Maize, a genetically diverse crop, is the domesticated descendent of its wild ancestor, teosinte. Recently, we have shown that certain maize landraces possess a valuable indirect defense trait not present in commercial hybrids. Plants of these landraces release herbivore-induced plant volatiles (HIPVs) that attract both egg [Trichogramma bournieri Pintureau & Babault (Hymenoptera: Trichogrammatidae)] and larval [Cotesia sesamiae Cameron (Hymenoptera: Braconidae)] parasitoids in response to stemborer egg deposition. In this study, we tested whether this trait also exists in the germplasm of wild Zea species. Headspace samples were collected from plants exposed to egg deposition by Chilo partellus Swinhoe (Lepidoptera: Crambidae) …

Pathogenicity And Performance Of Two Candidate Isolates Of Metarhizium Anisopliae And Beauveria Bassiana (Hypocreales: Clavicipitaceae) In Four Liquid Culture Media For The Management Of The Legume Pod Borer Maruca Vitrata (Lepidoptera: Crambidae), V. Tumuhaise, S. Ekesi, S. A. Mohamed, P. N. Ndegwa, L. W. Irungu, R. Srinivasan, N. K. Maniania

All Peer-Reviewed Publications

The aim of this study was to identify and develop entomopathogenic fungi as biopesticides for management of Maruca vitrata (Fabricius). Fourteen isolates of Metarhizium anisopliae (Metchnikoff) Sorokin and six of Beauveria bassiana (Bals.-Criv.) Vuill. were screened against first instar larvae of M. vitrata. The two most virulent isolates were selected and further tested for production in four liquid media. Different formulations of one isolate were evaluated against different developmental stages. Metarhizium anisopliae ICIPE 18 and ICIPE 69 caused highest larval mortality of 91 and 81%, with lethal time to 50% mortality (LT50) values of 1.8 and 1.7 days and LC50 …

Nebline, March 2015

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Feature: 4-H Ag Literacy Teaches Youth Where Their Food and Fiber Comes From

Food & Health

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Optimizing Western Flower Thrips Management On French Beans By Combined Use Of Beneficials And Imidacloprid, Johnson O. Nyasani, Sevgan Subramanian, Hans Michael Poehling, Nguya K. Maniania, Sunday Ekesi, Rainer Meyhöfer

All Peer-Reviewed Publications

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an important pest of vegetable crops worldwide and has developed resistance to many insecticides. The predatory mites Neoseiulus (=Amblyseius) cucumeris (Oudemans), the entomopathogenic fungus Metarhizium anisopliae (Metsch.), and an insecticide (imidacloprid) were tested for their efficacy to reduce WFT population density and damage to French bean (Phaseolus vulgaris L.) pods under field conditions in two planting periods. Metarhizium anisopliae was applied as a foliar spray weekly at a rate of one litre spray volume per plot while imidacloprid was applied as a soil drench every two weeks at a rate of two …

Nebline, February 2015

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

Feature: Extension Salutes Our Dedicated Volunteers, Worth Half a Million Dollars Annually

Food & Health

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