Entomology Commons^™

Population Occurrence And Pathogen Prevalence Of Lone Star (Acari: Ixodidae) Ticks Collected From Southeast Nebraska, Amanda C. Maegli

Department of Entomology: Dissertations, Theses, and Student Research

Lone star tick, Amblyomma americanum (L.), has recently become established in Nebraska; therefore, local biology, ecology, and tick-borne disease risk are not known. Research was conducted to determine monthly questing activity, establishment, and pathogenic microorganisms associated with the lone star tick in Nebraska.

Lone star tick populations were collected from May through August, 2012 in six sites in southeast Nebraska using carbon dioxide (CO₂) traps. A total of 747 adults, 3,076 nymphs, and 1,289 larvae were collected. Total ticks collected and monthly activity were significantly different for each site.

A semi-randomized sample of 251 adult ticks were selected …

Impact Of Wheat Streak Mosaic Virus And Triticum Mosaic Virus On Transmission By Aceria Tosichella Keifer (Eriophyidae) And Virus Epidemiology In Wheat, Camila F. De Oliveira

Department of Entomology: Dissertations, Theses, and Student Research

The wheat curl mite (WCM), Aceria tosichella Keifer, transmits a complex of viruses, Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV) and Wheat mosaic virus (WMoV), to wheat, Triticum aestivum, in the Great Plains. Co-infection of wheat by these viruses is frequently observed, increasing disease severity and yield loss.

Current genetic work classifies WCM populations into two genotypes, Type 1 and Type 2. It has been shown that different mite genotypes are able to transmit viruses at varying rates. WCM-virus relations are very specific and can impact vector biology. In this study, the primary objective was to determine …

Toxic And Repellent Effects Of Pyrethroids Used In Orchards On The Honey Bee, Apis Mellifera L. (Hymenoptera: Apidae), Erin M. Ingram

Department of Entomology: Dissertations, Theses, and Student Research

Managed honey bee colonies provide valuable pollination services and are rented by fruit orchards to improve fruit quality and yield. The placement of colonies in this agricultural setting increases the possibility of exposure to pyrethroids used for broad-spectrum pest control in orchards. Although highly toxic to bees, pyrethroids are believed to pose a relatively low hazard due to their low application rates in the field as well as their contact repellent properties. Previous studies have noted a decrease in foraging visits following pyrethroid application possibly preventing bees from acquiring a lethal dose in the field.

This research quantified behaviors associated …

Evaluation Of The Efficacy Of 1-Octen-3-Ol And Carbon Dioxide Chemoattractants With Mosquitoes And Bloodmeal Analysis Of Culex Mosquito Spp. In Lancaster County, Nebraska, Julianne N. Matczyszyn

Department of Entomology: Dissertations, Theses, and Student Research

The purpose of mosquito-borne disease surveillance is to assess the risk of pathogen transmission by assessing mosquito populations and the prevalence of disease pathogens in those populations. West Nile virus (WNV) is an important mosquito-borne virus in Nebraska, and can be transmitted by several mosquito species found in Lancaster County, Nebraska, including Culex pipiens L., Culex salinarius Coquillett, Culex restuans Theobald, Culex tarsalis Coquillett, Culex territans Walker, and Culex erraticus Dyar & Knab. These species are ornithophilic, yet many studies indicate a shift in host feeding to mammalian in late summer months. One-octen-3-ol (octenol) can be isolated …

Effects Of A Corn Root Defense Substance On Western Corn Rootworm Diabrotica Virgifera Virgifera Leconte Larvae, Zixiao Zhao

Department of Entomology: Dissertations, Theses, and Student Research

The objectives of this research were to evaluate the effects of hydroxamic acids, a group of corn root defense substances on western corn rootworm (Diabrotica virgifera virgifera LeConte) larvae and identify putative molecular mechanisms for hydroxamic acid detoxification. Corn line 428G carries a homozygous mutant bx1 gene, which makes it unable to synthesis hydroxamic acids. In contrast, H88 is the wild type parental line of 428G and is able to synthesize hydroxamic acids. Larvae were fed on 428G and H88 roots for 7 days for comparison. No significant difference was observed in growth, development, or survival rate. A RNA-Sequencing …

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 …