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Abundance Of Plodia Interpunctella (Hubner) And Cadra Cautella (Walker) Infesting Maize Stored On South Carolina Farms: Seasonal And Non-Seasonal Variation, Richard T. Arbogast, Shahpar R. Chini

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Seasonal trends and short-term fluctuations in abundance of Plodia interpunctella (Hubner) and Cadra cautella (Walker) infesting maize stored on two South Carolina farms were studied during three storage seasons (September 1990–June 1993). Coils of corrugated paper placed on the grain surface were used to trap mature larvae seeking pupation sites. Temperatures in the grain (18-cm-deep) and in the bin headspace were recorded hourly, and grain moisture content was measured weekly. Weekly mean numbers of moth larvae, and adults of two natural enemies, trapped in the coils were used for tracking changes in their abundance over time. The most significant findings …

Cryptic Plasmid Psku146 From The Wall-Less Plant Pathogen Spiroplasma Kunkelii Encodes An Adhesin And Components Of A Type Iv Translocation-Related Conjugation System, Robert E. Davis, Ellen L. Dally, Rasa Jomantiene, Yan Zhao, Bruce Roe, Shaoping Lin, Jonathan Shao

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A cryptic plasmid of the wall-less plant pathogenic mollicute, Spiroplasma kunkelii CR2-3X, was cloned and its sequence analyzed. The 14,615 bp plasmid, designated pSKU146, has a nucleotide content of 28 mol% G + C, and contains 18 potential protein-coding regions (open reading frames, ORFs), of which six encode proteins that exhibit similarity to virulence-associated proteins involved in cell-to-cell adhesion or conjugal DNA transfer. One ORF encodes a 96 kDa protein, SkARP1, that is highly similar to SARP1 adhesin involved in attachment of Spiroplasma citri to insect vector gut membrane. Five ORFs encode proteins similar to TraE and Mob in walled …

Carbaryl Resistance In Mexican Strains Of The Southern Cattle Tick (Acari: Ixodidae), Andrew Y. Li, Ronald B. Davey, John E. George

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Susceptibility to carbaryl in six Mexican strains of the southern cattle tick, Boophilus microplus (Canestrini), was evaluated with the Food and Agricultural Organization larval packet test. Tick strains from the cattle fever tick quarantine zone in Texas were more susceptible to carbaryl than to coumaphos or diazinon. Compared with the susceptible reference (Gonzalez) strain, Mexican tick strains demonstrated 10.9Ð59.5-fold resistance to carbaryl. SigniÞcant cross-resistance was found between carbaryl and the organophosphate acaricides coumaphos and diazinon. Bioassay results with synergists suggested that metabolic detoxification mechanisms did not play a major role in carbaryl resistance. Resistance to carbaryl was likely conferred by …

Insect Transmission Of Plant Pathogens, Rodrigo P. P. Almeida, Astri Wayadande, Todd Shelly

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Much of biological research conducted today is multidisciplinary, partly because of the availability of ever simpler to use molecular tools and the realization that ecological systems are complex and multitrophic. Although there is a general trend toward academic specialization and cooperation, some fields still require that scientists be aware of the “bigger picture.” We consider that the study of insect-transmitted plant pathogens is one of those fields, where insect, pathogen, and plant are inseparably linked. In this triangle of interactions, researchers focus their interests on questions at the molecular and cellular to epidemiological levels. Throughout the years, plant vector entomologists …

Maintenance Of A Narrow Host Range By Oxyops Vitiosa; A Biological Control Agent Of Melaleuca Quinquenervia, G. S. Wheeler

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Host range expansion in insect herbivores is often thought to be mediated by several factors, principal among them are secondary plant metabolites. In weed biological control, the host range of a prospective agent is one of the most important considerations in its implementation. Extensive host testing tests seek to determine the behavioral acceptance and nutritional value of different test plant species to the potential agent. A list of test plants is compiled that comprises species that are close taxonomic relatives of the target weed plus other species of economic or ecologic importance. The host testing of the Melaleuca quinquenervia biological …

Integration Of Co 2 Flux And Remotelysensed Data For Primary Production And Ecosystem Respiration Analyses In The Northern Great Plains: Potential For Quantitative Spatial Extrapolation, Tagir G. Gilmanov, Larry L. Tieszen, Bruce K. Wylie, Larry B. Flanagan, Albert B. Frank, Marshall R. Haferkamp, Tilden P. Meyers, Jack A. Morgan

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Aim Extrapolation of tower CO₂ fluxes will be greatly facilitated if robust relationships between flux components and remotely sensed factors are established. Long-term measurements at five Northern Great Plains locations were used to obtain relationships between CO₂ fluxes and photosynthetically active radiation (Q), other on-site factors, and Normalized Difference Vegetation Index (NDVI) from the SPOT VEGETATION data set.

The Vascular Flora Of Powhatan County, Virginia, Michael Austin Terry

Master's Theses

The project was undertaken with three main goals in mind: to provide as current and complete an account as possible of the flora of Powhatan County in the form of an annotated checklist; to integrate the information obtained from the inventory into phytogeographical and ecological generalizations currently being developed for the state of Virginia; and, to report any significant or anomalous discoveries. There is no previous county-wide inventory of plant diversity for Powhatan County. However, Corcoran (1981) published a list of plants from the Jones and Mill Creek watershed located in the Fine Creek Mills area of northeastern Powhatan.

Plant Composition Of Mixed-Grass Prairie Of Cedar Point Biological Research Station, Keith County, Nebraska, David A. Mckenzie

Biology Faculty Publications

This study involved a vegetation analysis of 15 permanent plots established on the short-grass and mixed grass prairie slopes at the Cedar Point Biological Station in Keith County, Nebraska. Ninety-nine species were found in the plots, including members of 75 genera and 31 families. Twenty-one were graminoids, 71 were forbs or succulents, 6 were shrubs and one was a tree. Bouteloua gracilis (19 % cover) and Carex filifolia (15 % cover) were the dominant graminoids at the site, while Yucca glauca (1% cover) and Artemisia frigida (1% cover) were the most frequent forbs. Comparisons of species richness by slope categories …

A Comment On The Results Reported By Çetin And Şen, Ari̇f Gönülol

Turkish Journal of Botany

No abstract provided.

2005 Plant Community Field Surveys In Western Nebraska, Robert F. Steinauer

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

These surveys were undertaken to provide biological data for the Nebraska Game and Parks Commission’s (NGPC) Nebraska Natural Legacy Action Plan. The specific intent was to identify, map, and give quality rankings to large blocks of privately-owned native plant communities within the survey area. In 2005, the surveys focused on Keith, Deuel, Cheyenne, Kimball, Banner, and Scotts Bluff counties, Sioux, Dawes and Sheridan counties north of the Pine Ridge, and Garden County south of the North Platte River.

Incorporating Molecular Identification Of Meloidogyne Spp. Into A Large-Scale Regional Nematode Survey, Thomas O. Powers, P. G. Mullin, T. S. Harris, L. A. Sutton, R. S. Higgins

Department of Plant Pathology: Faculty Publications

A regional nematode survey of potato fields was conducted in the central United States during 2002 and 2003. The survey encompassed seven states and included a morphological and molecular examination of nematodes of regulatory concern from 1,929 soil samples. No regulated pest species were recovered during this survey. Meloidogyne juveniles extracted from soil were identified by mitochondrial and 18S ribosomal molecular markers. Eighty-two DNA sequences representing the two marker regions for Meloidogyne species were submitted to GenBank to facilitate evaluation of marker variability. Sufficient 18S variation was observed among some Meloidogyne species to aid in identification; however, nucleotide sequence from …

Rich Mesic Forests: Edaphic And Physiographic Drivers Of Community Variation In Western Massachusetts, J. Bellemare, G. Motzkin, D. R. Foster

Biological Sciences: Faculty Publications

Rich Mesic Forest, a Northeastern variant of the species-rich Mixed Mesophytic Forest association of eastern North America, is an Acer saccharum-dominated forest type typically associated with calcareous bedrock and nutrient-rich, mull soils. Rich Mesic Forest (RMF) is a priority for conservation in the Northeast due to its limited areal extent, high plant species richness, and numerous rare taxa, yet the community characteristics and environmental correlates of this forest type are incompletely understood. This study undertook a quantitative classification of RMF of the northeastern edge of the Berkshire Plateau in western Massachusetts. Cluster analysis of data from ten sites identified two …

Response Of Sagebrush Steppe Species To Elevated Co2 And Soil Temperature, Melissa S. Lucash, Blake Farnsworth, William E. Winner

Environmental Science and Management Faculty Publications and Presentations

Elevated atmospheric CO₂ may cause long-term changes in the productivity and species composition of the sagebrush steppe. Few studies, however, have evaluated the effects of increased CO₂ on growth and physiology of species important to this ecosystem. Since the response of plants to elevated CO₂ may be limited by environmental factors, soil temperature was also examined to determine if low soil temperatures limit CO₂ response. To determine how CO₂ and soil temperature affect the growth of species native to the sagebrush steppe, bottlebrush squirreltail [Elymus elymoides (Raf.) Swezey], Thurber needlegrass (Stipa thurberiana Piper), …

Incorporating Glass Transition Concepts To Explain Rice Milling-Quality Reductions During The Drying Process, Derek A. Schluterman, Terry J. Siebenmorgen

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Previous research has indicated that while drying rough rice using air temperatures above the glass transition temperature (Tg), head rice yield (HRY) reductions are incurred if a state transition occurs when severe intra-kernel moisture content (MC) gradients are present. State transitions can occur by extended drying using high-temperature air or by cooling kernels below Tg before sufficient tempering has occurred. The objectives of this experiment were to determine the maximum MC removal per initial drying pass and the associated tempering durations required to prevent HRY reduction. Two long-grain cultivars, ‘Francis’ and ‘Wells’, at two harvest moisture contents (HMC) were used. …

A Correction To “New Records Of The Myxobiota Of Turkey” By R. Batur And C. Cem Ergül, C. Cem Ergül

Turkish Journal of Botany

No abstract provided.

Morphogenesis In Germinating Fusarium Graminearum Macroconidia, Steven D. Harris

Department of Plant Pathology: Faculty Publications

Fusarium graminearum (teleomorph Gibberella zeae) is a significant pathogen of wheat and corn. F. graminearum forms multicellular macroconidia that play an important role in dissemination of the disease. The spatial pattern of morphogenesis in germinating macroconidia is described. Germ tubes preferentially emerge from the apical cells in a bipolar pattern that appears to be common to filamentous fungi. Chitin deposition occurs at two locations: the spore apices and cortical regions of macroconidial cells that subsequently produce a germ tube. The spatial pattern of morphogenesis requires the presence of functional microtubules, which may be responsible for the transport of key …

Vegetable Gardening, Rhoda Burrows, David Graper

SDSU Extension Circulars

This circular provides information on planning, planting, and growing a vegetable garden. Topics include: soil preparation, planting, irrigation, weed control, insect and disease control, crop selection, and vegetable preservation and storage.

Isolation And Characterization Of A Bovine Visceral Endoderm Cell Line Derived From A Parthenogenetic Blastocyst, Neil C. Talbot, Thomas J. Caperna, Anne M. Powell, Alan D. Ealy, Le Ann Blomberg, Wesley M. Garrett

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A cell line, BPE-1, was derived from a parthenogenetic 8-d in vitro-produced bovine blastocyst that produced a cell outgrowth on STO feeder cells. The BPE-1 cells resembled visceral endoderm previously cultured from blastocysts produced by in vitro fertilization (IVF). Analysis of the BPE-1 cells demonstrated that they produced serum proteins and were negative for interferon-tau production (a marker of trophectoderm). Transmission electron microscopy revealed that the cells were a polarized epithelium connected by complex junctions resembling tight junctions in conjunction with desmosomes. Rough endoplasmic reticulum was prominent within the cells as were lipid vacuoles. Immunocytochemistry indicated the BPE-1 cells …

Laboratory Bioassays Of Entomopathogenic Fungi For Control Of Delia Radicum (L.) Larvae, Denny J. Bruck, Jane E. Snelling, Amy J. Dreves, Stefan T. Jaronski

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Laboratory soil bioassays were performed at economic Weld rates for in-furrow (3.85 x 10⁶ spores/g dry soil) and broadcast (3.85 x 10⁵ spores/g dry soil) applications with three isolates of Metarhizium anisopliae (F52, ATCC62176, and ARSEF5520) and one isolate of Beauveria bassiana (GHA). All isolates tested were infective to second instar Delia radicum (L.). The conditionally registered M. anisopliae isolate (F52) performed best killing an average of 85 and 72% of D. radicum larvae at the high and low concentration, respectively. The mean LC50 and LC95 of F52 against second instar D. radicum was 2.7 x 10^{6 …}

Apoplastic Redox Metabolism: Synergistic Phenolic Oxidation And A Novel Oxidative Burst, C. Jacyn Baker, Daniel P. Roberts, Norton M. Mock, Bruce D. Whitaker, Kenneth L. Deahl, Andrey A. Aver'yanov

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The plant apoplast is an important mediator of communication between the cell cytoplasm and its surroundings. Plant cell suspensions offer a convenient model system to gain insight into apoplastic physiology. Here, we describe a novel phenomenon that took place when two naturally occurring phenolics were added together to either soybean or tobacco cell suspensions. Acetosyringone (AS) and/or hydroxyacetophenone (HAP), phenolics found in the extracellular/apoplast of tobacco cells, were added to soybean or tobacco cell suspensions undergoing an oxidative burst. Individually, AS appeared to be utilized as a typical peroxidase substrate to scavenge hydrogen peroxide, while HAP was utilized at a …

From Metchnikoff To Monsanto And Beyond: The Path Of Microbial Control, Jeffrey C. Lord

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

In 125 years since Metchnikoff proposed the use of Metarhizium anisopliae to control the wheat cockchafer and brought about the first field trials, microbial control has progressed from the application of naturalists’ observations to biotechnology and precision delivery. This review highlights major milestones in its evolution and presents a perspective on its current direction. Fungal pathogens, the most eye-catching agents, dominated the early period, but major mycological control efforts for chinch bugs and citrus pests in the US had questionable success, and interest waned. The discoveries of Bacillus popilliae and Bacillus thuringiensis began the era of practical and commercially viable …

Composition Of Irrigation Water Salinity Affects Growth Characteristics And Uptake Of Selenium And Salt Ions By Soybean, D. Wang, C. M. Grieve, D. L. Suarez

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

A greenhouse study was conducted to determine the effects of irrigation waters differing in salt composition on growth characteristics, salt ion and selenium (Se) accumulation, and distribution in plant components of the soybean (Glycine max L. Merr.) cultivar “Manokin.” Plants were grown in sand cultures and irrigated with isoosmotic solutions containing (1) Cl⁻ as the dominant anion, or (2) a mixture of salts containing equal molar amounts of SO_^2-4  and Cl⁻. Six treatments of each salinity type were imposed. Electrical conductivities of the irrigation waters ranged from 2.1 to 13.0 dSm⁻¹. Selenium …

Key Grazing Levels (Foo Targets) For Pasture And Sheep Management, Department Of Agriculture, Western Australia

Animal production and livestock published reports

Food On Offer (FOO) is the amount of pasture in front of an animal, and is measured in kilograms Dry Matter per hectare. Managing pastures to key grazing levels - or FOO targets - can result in improved production of grazing systems in Mediterranean environments which are characterized by slow winter growth, peak spring growth and dry summers. These targets vary according to what production response is required.

This information sheet illustrates key target FOO for sheep grazing annual pastures during autumn and spring.

Chlorovirus: A Genus Of Phycodnaviridae That Infects Certain Chlorella-Like Green Algae, Ming Kang, David Dunigan, James L. Van Etten

Department of Plant Pathology: Faculty Publications

Taxonomy: Chlorella viruses are assigned to the family Phycodnaviridae, genus Chlorovirus, and are divided into three species: Chlorella NC64A viruses, Chlorella Pbi viruses and Hydra viridis Chlorella viruses. Chlorella viruses are large, icosahedral, plaque-forming, dsDNA viruses that infect certain unicellular, chlorella-like green algae. The type member is Paramecium bursaria chlorella virus 1 (PBCV-1).

Physical properties: Chlorella virus particles are large (molecular weight ~1 × 10⁹ Da) and complex. The virion of PBCV-1 contains more than 100 different proteins; the major capsid protein, Vp54, comprises ~40% of the virus protein. Cryoelectron microscopy and three-dimensional image reconstruction of PBCV-1 virions …

Proline Suppresses Apoptosis In The Fungal Pathogen Colletotrichum Trifolii, Changbin Chen, Martin B. Dickman

Department of Plant Pathology: Faculty Publications

The role of reactive oxygen species (ROS) in cell communication, control of gene expression, and oxygen sensing is well established. Inappropriate regulation of ROS levels can damage cells, resulting in a diseased state. In Colletotrichum trifolii, a fungal pathogen of alfalfa, the mutationally activated oncogenic fungal Ras (DARas) elevates levels of ROS, causing abnormal fungal growth and development and eventual apoptotic-like cell death but only when grown under nutrient-limiting conditions. Remarkably, restoration to the wild-type phenotype requires only proline. Here, we describe a generally unrecognized function of proline: its ability to function as a potent antioxidant and inhibitor of …

Chlorella Virus Marburg Topoisomerase Ii: High Dna Cleavage Activity As A Characteristic Of Chlorella Virus Type Ii Enzymes, Jennifer S. Dickey, Tae-Jin Choi, James L. Van Etten, Neil Osheroff

Department of Plant Pathology: Faculty Publications

Although the formation of a covalent enzyme-cleaved DNA complex is a prerequisite for the essential functions of topoisomerase II, this reaction intermediate has the potential to destabilize the genome. Consequently, all known eukaryotic type II enzymes maintain this complex at a low steady-state level. Recently, however, a novel topoisomerase II was discovered in Paramecium bursaria chlorella virus-1 (PBCV-1) that has an exceptionally high DNA cleavage activity [Fortune et al. (2001) J. Biol. Chem. 276, 24401-24408]. If robust DNA cleavage is critical to the physiological functions of chlorella virus topoisomerase II, then this remarkable characteristic should be …

Processing Of Yield Map Data, J. L. Ping, Achim R. Dobermann

Department of Agronomy and Horticulture: Faculty Publications

Yield maps reflect systematic and random sources of yield variation as well as numerous errors caused by the harvest and mapping procedures used. A general framework for processing of multi-year yield map data was developed. Steps included (1) raw data screening, (2) standardization, (3) interpolation, (4) classification of multi-year yield maps, (5) post-classification spatial filtering to create spatially contiguous yield classes, and (6) statistical evaluation of classification results. The techniques developed allow more objective mapping of yield zones, which are an important data layer in algorithms for prescribing variable rates of production inputs.

Environmental Factors Affecting Seed Persistence Of Annual Weeds Across The U.S. Corn Belt, Adam S. Davis, John Cardina, Frank Forcella, Gregg A. Johnson, George Kegode, John L. Lindquist, Edward C. Luschei, Karen A. Renner, Christy L. Sprague, Martin M. Williams Ii

Department of Agronomy and Horticulture: Faculty Publications

Weed seedbanks have been studied intensively at local scales, but to date, there have been no regional-scale studies of weed seedbank persistence. Empirical and modeling studies indicate that reducing weed seedbank persistence can play an important role in integrated weed management. Annual seedbank persistence of 13 summer annual weed species was studied from 2001 through 2003 at eight locations in the north central United States and one location in the northwestern United States. Effects of seed depth placement, tillage, and abiotic environmental factors on seedbank persistence were examined through regression and multivariate ordinations. All species examined showed a negative relationship …

Influence Of Soybean Row Width And Velvetleaf Emergence Time On Velvetleaf (Abutilon Theophrasti), Shawn M. Hock, Stevan Z. Knezevic, Alex R. Martin, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Row spacing and the relative time of velvetleaf emergence affects the time of soybean canopy closure relative to velvetleaf, influencing the growth and development of velvetleaf. Field studies were conducted in northeastern Nebraska in 2002 and 2003 to describe velvetleaf growth as influenced by soybean presence or absence (velvetleaf grown with soybean or in monoculture), soybean row spacing (19 and 76 cm), and relative time of velvetleaf emergence. Velvetleaf seed production, leaf area (LA), and total dry matter (TDM) were greater in 76-cm- than in 19-cm-wide soybean rows. LA, TDM, and seed production of velvetleaf were reduced with later emergence …

Species Diversity And Functional Composition Of Pastures That Vary In Landscape Position And Grazing Management, John A. Guretzky, Kenneth J. Moore, E. Charles Brummer, C. Lee Burras

Department of Agronomy and Horticulture: Faculty Publications

The productivity of grasslands depends in part on their diversity of species and functional composition. Our objective was to examine the effects of three landscape positions (summit, backslope, and toe-slope) and three stocking systems (continuous, rotational, and non-grazed) on species diversity and percentage of cover of grass, legume, and weed species functional types in southeastern Iowa pastures.Data were collected in 0.2-m² plots randomly distributed throughout each of four replicate pastures in spring and summer 2000 and 2001. Backslope landscape positions within pastures managed with either continuous or rotational stocking contained the greatest overall diversity of species. Across years, overall …