Entomology Commons^™

Impact Of The Timing And Use Of An Insecticide On Arthropods In Cover-Crop-Corn Systems, Gabriela Inveninato Carmona, Emily Robinson, Julia Nogueira Duarte Campos, Anthony Justin Mcmechan

Department of Entomology: Faculty Publications

Cover crops provide a habitat for pests and beneficial arthropods. Unexpected pest pressure in a cover-crop-to-corn system can occur and result in increased use of insecticides. Eight site-years of on-farm field studies were conducted in 2019, 2020, and 2021. The objective of the study was to evaluate the impact of insecticide timing relative to cover-crop termination on arthropod activity in a cover-crop-to-corn system. The treatments consisted of (i) glyphosate to terminate the cover crop, (ii) glyphosate and pyrethroid tank mix to terminate the cover crop, and (iii) glyphosate to terminate the cover crop and pyrethroid application 25 days after the …

The Impact Of Beneficial Organisms In Corn Agroecosystems, Callie Rosalind Braley

Doctor of Plant Health Program: Dissertations and Student Research

Corn is one of the world’s, and Nebraska’s, most important crops. Millions of acres are planted to corn each year in the Cornhusker State. However, each year there are a plethora of arthropod, weed, and microorganism pests that rob farmers of reaching their maximum yield potential. There are many options available to manage these pests in corn agroecosystems, but one option is often underutilized: beneficial organisms. For each pest, there are a variety of natural enemies that can assist in mitigating the damage caused by pests.

Many beneficial organisms exist, and they can be grouped by the type of pest …

Developing A Method To Contain The Feeding Of The Wheat Curl Mite (Aceria Tosichella Keifer), Pierce Leef, Gary Hein

UCARE Research Products

To better understand the ecology and epidemiology of the wheat curl mite (Aceria tosichella Keifer) as a vector of wheat streak mosaic virus (WSMV), it is necessary to develop a method to confine the microscopic mites and their infection to specific areas of their host plants, particularly wheat and corn. In this study, corn was the plant of interest. The device developed for this mite-confining method was made by removing the lens of a phone camera lens clip and gluing a 2.5 cm x 4.5 cm piece of wood to the other arm of the clip. Clips were utilized by …

Using Adults To Monitor Rnai Susceptibility Of Western Corn Rootworm, Diabrotica Virgifera Virgifera Leconte, Field Populations, Matthew Welter

Department of Entomology: Dissertations, Theses, and Student Research

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is the most damaging corn pest in the U.S. Corn Belt, costing producers over $1 billion annually in control and damage costs. Currently, corn producers rely on three control strategies for WCR management: crop rotation, chemical insecticides, and transgenic corn expressing Bacillus thuringiensis Berliner (Bt) proteins. Populations of WCR have evolved resistance to all of these tactics, limiting effective control strategies for producers. RNA interference (RNAi), is the newest mode of action developed for WCR management. In July 2017, the first RNAi plant-incorporated protectant (PIP) corn product was approved for production …

Wheat Stem Maggot (Diptera: Chloropidae): An Emerging Pest Of Cover Crop To Corn Transition Systems, Gabriela Inveninato Carmona, Jennifer M. Rees, Ronald C. Seymour, Robert J. Wright, Anthony J. Mcmechan

Department of Entomology: Faculty Publications

The wheat stem maggot (Meromyza americana Fitch) (WSM) is a minor pest of wheat, rye, and other grasses. In 2017, growers in Nebraska reported dead center whorls and excessive tillering in early-season cornfields that followed wheat or rye terminated after planting corn. A survey was conducted to evaluate the risk factors for this insect in cover crop to corn transition systems. In each field, management practices and the percentage of injured plants were recorded. Symptomatic corn plants were collected from each field and dissected to determine larval and plant characteristics. In a few cases, small patches of a field …

Characterization Of The Natural Enemy Community, With Emphasis On Entomopathogens, For Management Of Western Corn Rootworm (Diabrotica Virgifera Virgifera) In West Central Nebraska, Camila Oliveira-Hofman

Department of Entomology: Dissertations, Theses, and Student Research

Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae),the western corn rootworm (WCR), is a major pest of corn (Zea mays L.) in the United States and Europe. WCR management options comprise mainly transgenic hybrids, insecticide applications and crop rotation. WCR is highly adaptable to management practices and field-evolved resistance to transgenic corn, insecticides and crop rotation in the United States Corn Belt has been reported. Therefore, the motivation for this project was to look into alternative options for WCR management. The goal of this dissertation is to characterize the natural enemies from irrigated commercial cornfields in Nebraska and examine their …

Evaluation Of Seed Treatments And At-Plant Soil Insecticides For The Control Of Wireworms (Coleoptera: Elateridae) In Field Corn, 2015, Kayla A. Mollet, Jonas Victor De Macedo, Grace E. Hirzel, C. Oliveira-Hofman, Julie A. Peterson

Department of Entomology: Faculty Publications

Wireworms are an important pest of corn, other field crop seedlings, and vegetables and can cause significant damage if not controlled. This field trial was established to evaluate the efficacy of neonicotinoid seed treatments and in-furrow soil insecticides to protect seedling field corn under a heavy wireworm pressure scenario. The trial was conducted on a commercial production field in Perkins County near Madrid, NE (40.781993° N, −101.463666° W). The field was selected for its likelihood to have heavy wireworm pressure due to the following: 1) past farmer observations of crop damage when planted to field corn in 2012; 2) sandy …

Spatial Variation In Western Corn Rootworm (Coleoptera: Chrysomelidae) Susceptibility To Bacillus Thuringiensis Corn Events In Nebraska, Jordan D. Reinders

Department of Entomology: Dissertations, Theses, and Student Research

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is an economically important pest species of field corn (Zea mays L.) in the U.S. Corn Belt. Yield losses and control costs exceed greater than $1 billion annually. Over the past 10+ years, growers have adopted transgenic corn hybrids expressing rootworm-active Bacillus thuringiensis (Bt) proteins as a primary WCR management tactic. Field-evolved resistance to Cry3Bb1 and mCry3A proteins expressed in single-trait Bt hybrids has been confirmed in some areas of Nebraska. Growers have used different tactics as needed to prevent or mitigate resistance, resulting in a mosaic of selection pressure placed …

A Brief History Of Corn: Looking Back To Move Forward, Jon Derek Pruitt

Doctor of Plant Health Program: Dissertations and Student Research

Maize was domesticated from teosinte in Mexico some 7,000 to 10,000 years ago and quickly spread through the Americas. It has become one of the most important crops at a local and global level. Two types, Northern Flint corn and Southern Dent corns provided the basis of the genetic background of modern maize hybrids. The development of hybrids, first double-cross and later single-cross hybrids, along with a transition to high input farming provided huge yield increases, which have continued to improve with improving technology.

Increase in maize production also caused a rise in Western corn Rootworm (Diabrotica virgifera virgifera …

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 …

Natural Distribution Of Parasitoids Of Larvae Of The Fall Armyworm, Spodoptera Frugiperda, In Argentina, M Gabriela Murua, Jamie Molina Ochoa, Patricio Fidalgo

Department of Entomology: Faculty Publications

Abstract To develop a better understanding of the natural distribution of the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), and to update the knowledge of the incidence of its complex of parasitoids. S. frugiperda, samplings in whorl-stage corn were carried out in provinces of Argentina from 1999 to 2003. S. frugiperda larvae were collected from corn in localities of the provinces of Tucumán, Salta, Jujuy, Santiago del Estero, La Rioja, Córdoba, San Luis, Chaco and Misiones. In each locality 30 corn plants were sampled and only larvae located in those plants were collected. The parasitoids that emerged from S. …

Natural Distribution Of Hymenopteran Parasitoids Of Spodoptera Frugiperda (Lepidoptera: Noctuidae) Larvae In Mexico, Jaime Molina-Ochoa, James E. Carpenter, Roberto Lezama-Gutiérrez, John E. Foster, Martín González-Ramírez, César Andres Angel-Sahagún, Javier Farías-Larios

Department of Entomology: Faculty Publications

Se llevó a cabo un inventario de parasitoides de larvas del gusano cogollero, Spodoptera frugiperda (J. E. Smith) (FAW) colectadas principalmente de maizales en estado de verticilio en seis estados mexicanos durante Agosto y Septiembre de 2000. Trece géneros de parasitoides himenópteros fueron recuperados, representando a tres familias, Braconidae: Aleoides, Chelonus, Cotesia, Glyptapanteles, Homolobus, y Meteorus); Ichneumonidae: Campoletis, Eiphosoma, Ophion, y Pristomerus; y Eulophidae: Aprostocetus, Euplectrus, y Horismenus. De un total de 5591 larvas colectadas, 772 produjeron parasitoides, para una tasa de parasitismo de 13.8%. La tasa de parasitismo más alta para una colecta simple fué …

Influence Of Western Corn Rootworm (Coleoptera: Chrysomelidae) Larval Injury On Yield Of Different Types Of Maize, Mario A. Urías-López, Lance J. Meinke

Department of Entomology: Faculty Publications

Two field experiments were conducted in 1995-1996 to determine if there are common yield responses among maize hybrids to larval western corn rootworm, Diabrotica virgifera virgifera LeConte injury. Three yellow dent hybrids, five white food grade dent hybrids, and a popcorn hybrid were included in the study. The minimum level of rootworm injury as measured by root damage ratings (3.2-4.2) that significantly reduced yield was similar across the hybrids included in the study. However, the pattern of yield response to different rootworm injury levels varied among hybrids. This suggests that maize hybrids may inherently differ in their ability to tolerate …

Larval Susceptibility Of An Insecticide-Resistant Western Corn Rootworm (Coleoptera: Chrysomelidae) Population To Soil Insecticides: Laboratory Bioassays, Assays Of Detoxification Enzymes, And Field Performance, Robert J. Wright, Michael E. Scharf, Lance J. Meinke, Xuguo Zhou, Blair D. Siegfried, Laurence D. Chandler

Department of Entomology: Faculty Publications

Soil insecticides were evaluated in laboratory and field studies against larvae of an insecticide resistant population (Phelps County, NE) of western corn rootworm, Diabrotica virgifera virgifera LeConte. Insecticide toxicity was evaluated by topical application of technical insecticides to 3rd instars from Saunders County, NE (susceptible) and Phelps County populations. Resistance ratios (LD₅₀ Phelps County/LD₅₀ Saunders County) for the insecticides methyl parathion, tefluthrin, carbofuran, terbufos, and chlorpyrifos were 28.0, 9.3, 8.7, 2.6 and 1.3, respectively. Biochemical investigation of suspected enzymatic resistance mechanisms in 3rd instars identified significant elevation of esterase activity (alpha and beta naphthyl acetate hydrolysis [3.8- and …

Influence Of Western Corn Rootworm (Coleoptera: Chrysomelidae) Larval Injury On Photosynthetic Rate And Vegetative Growth Of Different Types Of Maize, Mario A. Urías-López, Lance J. Meinke, Leon G. Higley, Fikru J. Haile

Department of Entomology: Faculty Publications

Two field experiments were conducted in 1995-1996 to determine if there are common photosynthetic and vegetative growth responses among genotypes of maize, Zea mays L., to larval western corn rootworm, Diabrotica virgifera virgifera LeConte injury. Specific variables measured from rootworm infested and noninfested plants were midday leaf photosynthetic rate, plant growth stage, and plant height during 9-18 leaf growth stages. Three yellow-dent hybrids, five white food-grade dent hybrids, and a popcorn hybrid were included in the study. Results suggest that there may be a common negative photosynthetic response within maize to larval injury during vegetative growth stages. Transient reductions in …

Pesticide Use On Crops In Nebraska - 1987, Maurice Baker, Nancy Peterson, Shripat T. Kamble

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

This is the third and most comprehensive study of pesticide use on crops in Nebraska. The first was completed in 1978 and the second one in 1982. The first study indicated that approximately 25 million pounds (11.34 million kg) of active ingredients were used on the major crops in Nebraska. This increased to approximately 30.2 million pounds (13.7 million kg) in 1982. The USDA requires accurate information to meet their responsibilities. Thus, this survey was undertaken to determine: 1) the use of pesticides on crops, pasture and rangeland and 2) to identify pest management practices.

Bionomics Of Insects Associated With Corn In The Nebraska Sandhills, J. L. Wedberg, J. B. Campbell, T. J. Helms

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

Investigations were conducted in the Nebraska Sandhills to determine the impact of transition from grassland to irrigated corn on selected insect species, to identify indigenous species that may be economically important to corn production, and to provide a point of reference for future development of pest management programs for irrigated corn.

The Biology And Ecology Of Trogoderma Glabrum (Herbst) In Stored Grains, Benjamin H. Kantack, Robert Staples

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

These investigations were undertaken to determine the distribution and importance of Trogoderma glabrum (Herbst) in stored grain in Nebraska, the ecological factors favoring population increase in stored wheat, corn, and sorghum, and the role T. glabrum might play in disseminating internally the Aspergillus molds commonly encountered in stored grain.

Ec1506 Corn Rootworm Control In Nebraska, Ephriam Hixson, Martin H. Muma, Roscoe E. Hill

University of Nebraska-Lincoln Extension: Historical Materials

Extension circular 1506 discusses corn rootworm control in Nebraska.

Fifty Years Of Achievement In Agricultural Investigation, R. T. Prescott

Nebraska Agricultural Experiment Station: Historical Circulars

In Nebraska, a hustling frontier state in 1887, the legislature hesitated not at all in taking advantage of the provisions of the Hatch Act, and now that fifty years have elapsed since the Station was founded, seventy-five years since the Land Grant College Act was passed and the U. S. Department of Agriculture established, and almost twenty-five years since the Agricultural Extension Service was added, it seems worth while to present a general summary of achievement within the state. The main object will be to show some of the important things that have been learned through the investigations of the …

A Key To The Nebraska Cutworms And Armyworms That Attack Corn, Don B. Whelan

Historical Research Bulletins of the Nebraska Agricultural Experiment Station

The following key to the Nebraska cutworms and armyworms injurious to corn is based upon structural characters supplemented in some instances by color. Not all of the species in this key have been found in Nebraska; some are included because they are to be found in near-by states to such an extent that they probably are present in this state.