Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 61

Full-Text Articles in Life Sciences

A Preliminary Analysis Of The Effects Of Hr 2454 On U.S. Agriculture, Economic Research Service Jul 2009

A Preliminary Analysis Of The Effects Of Hr 2454 On U.S. Agriculture, Economic Research Service

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

USDA performed a preliminary economic analysis of the impacts of House-passed climate legislation, HR 2454, on U.S. agriculture. The analysis assumes no technological change, no alteration of inputs in agriculture, and no increase in demand for bio-energy as a result of higher energy prices. Therefore, it overstates the impact of the climate legislation on agriculture costs in the short (2012-18), medium (2027-2033), and long-term (2042 to 2048). In USDA’s analysis, short-term costs remain low in part because of provisions in HR 2454 that reduce the impacts of the bill on fertilizer costs. In fact, the impact on net farm income …


Effect Of Nitrogen Application Timing On Corn Production Using Subsurface Drip Irrigation, David D. Tarkalson, Simon J. Van Donk, James L. Petersen Mar 2009

Effect Of Nitrogen Application Timing On Corn Production Using Subsurface Drip Irrigation, David D. Tarkalson, Simon J. Van Donk, James L. Petersen

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

The use of subsurface drip irrigation (SDI) in row-crop agriculture is increasing because of potential increases in water and nutrient use efficiency. Research-based information is needed to manage N applications through SDI systems in field corn (Zea-mays L.) production. This study was conducted to assess the effect of different in-season SDI system N application timings on corn production and residual soil N03-N at the University of Nebraska-Lincoln West Central Research and Extension Center in North Platte, Neb, on a Cozad silt loam (fine-silty, mixed, mesic Fluventic Haplustoll). We evaluated the effect of three N application timing methods …


Comparison Of Runoff, Soil Erosion, And Winter Wheat Yields From No-Till And Inversion Tillage Production Systems In Northeastern Oregon, J.D. Williams, H. T. Gollany, M.C. Siemens, S.B. Wuest, D. S. Long Feb 2009

Comparison Of Runoff, Soil Erosion, And Winter Wheat Yields From No-Till And Inversion Tillage Production Systems In Northeastern Oregon, J.D. Williams, H. T. Gollany, M.C. Siemens, S.B. Wuest, D. S. Long

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

Conservation tillage systems that reduce soil erosion and maintain or increase soil carbon offer long-term benefits for producers in the inland Pacific Northwestern United States but could result in reduced grain yields due to increased pressure from weeds, disease, and insect pests. Our objective was to compare runoff, soil erosion, and crop yields from a conventional tillage, wheat-fallow two-year rotation and a no-till four-year rotation. The experiment was undertaken within a small watershed to provide results that would be repre¬sentative of conservation effectiveness at the field scale. Two neighboring drainages, 5.8 and 10.7 ha (14 and 26 ac), in the …


Upic: Perl Scripts To Determine The Number Of Ssr Markers To Run, R. S. Arias, Linda L. Ballard, Brian E. Scheffler Jan 2009

Upic: Perl Scripts To Determine The Number Of Ssr Markers To Run, R. S. Arias, Linda L. Ballard, Brian E. Scheffler

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

We introduce here the concept of Unique Pattern Informative Combinations (UPIC), a decision tool for the cost-effective design of DNA fingerprinting/genotyping experiments using simple-sequence/tandem repeat (SSR/STR) markers. After the first screening of SSR-markers tested on a subset of DNA samples, the user can apply UPIC to find marker combinations that maximize the genetic information obtained by a minimum or desirable number of markers. This allows a cost-effective planning of future experiments. We have developed Perl scripts to calculate all possible subset combinations of SSR markers, and determine based on unique patterns or alleles, which combinations can discriminate among all DNA …


Microsatellites Reveal Genetic Diversity In Rotylenchulus Reniformis Populations, R. S. Arias, Salliana R. Stetina, Jennifer L. Tonos, Jodi A. Scheffler, Brian E. Scheffler Jan 2009

Microsatellites Reveal Genetic Diversity In Rotylenchulus Reniformis Populations, R. S. Arias, Salliana R. Stetina, Jennifer L. Tonos, Jodi A. Scheffler, Brian E. Scheffler

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

Rotylenchulus reniformis is the predominant parasitic nematode of cotton in the Mid South area of the United States. Although variable levels of infection and morphological differences have been reported for this nematode, genetic variability has been more elusive. We developed microsatellite-enriched libraries for R. reniformis, produced 1152 clones, assembled 694 corstigs, detected 783 simple sequence repeats (SSR) and designed 192 SSR-markers. The markers were tested on six R. reniformis cultures from four states, Texas, Louisiana, Mississippi and Georgia, in the USA. Based oil performance we selected 156 SSR markers for R. reniformis from which 88 were polymorphic across the …


Wus And Stm-Based Reporter Genes For Studying Meristem Development In Poplar, Y. Bao, P. Dharmawardhana, R. S. Arias, M. B. Allen, C. Ma, Steven H. Strauss Jan 2009

Wus And Stm-Based Reporter Genes For Studying Meristem Development In Poplar, Y. Bao, P. Dharmawardhana, R. S. Arias, M. B. Allen, C. Ma, Steven H. Strauss

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

We describe the development of a reporter system for monitoring meristem initiation in poplar using promoters of poplar homologs to the meristem-active regulatory genes WUSCHEL (WUS) and SHOOTMERISTEMLESS (STM). When ~3 kb of the 5' flanking regions of close homologs were used to drive expression of the GUSPlus gene, 50–60% of the transgenic events showed expression in apical and axillary meristems. However, expression was also common in other organs, including in leaf veins (40 and 46% of WUS and STM transgenic events, respectively) and hydathodes (56% of WUS transgenic events). Histochemical GUS staining of explants during callogenesis and shoot …


Tests Of Concepts For Streamflow Sampler Design, John A. Replogle Jan 2009

Tests Of Concepts For Streamflow Sampler Design, John A. Replogle

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

Total-load sampling has been a perpetual problem in sediment monitoring. Usually a combination of bed-load sampling devices, suspended load suction samplers, and some kind of flume, for total flow rate, is used. Total-load, sediment-sampler-design concepts that can perform all three of these functions are proposed. The resulting designs would require installation at sites that can provide a step-overfall height about equal to the maximum channel flow depth. The concepts are simple, but appear to have been overlooked or ignored for the past many decades, and are based on a moving conveyor belt that is long and wide, with many slots, …


Protocol For Indicator Scoring In The Soil Management Assessment Framework (Smaf), Brian J. Wienhold, D. L. Karlen, S.S. Andrews, D. E. Stott Jan 2009

Protocol For Indicator Scoring In The Soil Management Assessment Framework (Smaf), Brian J. Wienhold, D. L. Karlen, S.S. Andrews, D. E. Stott

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

Assessment tools are needed to evaluate agronomic management effects on critical soil functions such as carbon sequestration, nutrient cycling and water partitioning. These tools need to be flexible in terms of selection of soil functions to be assessed and indicators to be measured to ensure that assessments are appropriate for the management goals. The soil management assessment framework (SMAF) is being developed to meet this need. The SMAF uses soil physical, chemical and biological indicator data to assess management effects on soil function using a three-step process for (1) indicator selection, (2) indicator interpretation and (3) integration into an index. …


Sorption Of Phosphorus From Swine, Dairy, And Poultry Manures, Carl H. Bolster, Karamat R. Sistani Jan 2009

Sorption Of Phosphorus From Swine, Dairy, And Poultry Manures, Carl H. Bolster, Karamat R. Sistani

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

In most phosphorus (P) sorption studies, P is added as an inorganic salt to a predefined background solution such as calcium chloride (CaCl2) or potassium chloride (KCl); however, in many regions, the application of P to agricultural fields is in the form of animal manure. The purpose of this study, therefore, was to compare the sorption behavior of dissolved reactive P (DRP) in monopotassium phosphate (KH2PO4)–amended CaCl2 and KCl solutions with sorption behavior of DRP in three different animal manure extracts. Phosphorus single-point isotherms (PSI) were conducted on eight soils with the following …


Nitrogen And Phosphorus Accumulation In Pasture Soil From Repeated Poultry Litter Application, Zhongqi He, C. Wayne Honeycutt, Irenus A. Tazisong, Zachary N. Senwo, Donglin Zhang Jan 2009

Nitrogen And Phosphorus Accumulation In Pasture Soil From Repeated Poultry Litter Application, Zhongqi He, C. Wayne Honeycutt, Irenus A. Tazisong, Zachary N. Senwo, Donglin Zhang

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

Poultry litter (PL) is a traditionally inexpensive and effective fertilizer to improve soil quality and agricultural productivity. However, over application to soil has raised concern because excess nutrients in runoff could accelerate the eutrophication of fresh water. In this work, we determined the contents of total phosphorus (P), Mehlich 3 extracted P, total nitrogen (N), ammonium (NH4)-N, and nitrate (NO3)-N, in pasture soils receiving annual poultry litter applications of 0, 2.27, 2.27, 3.63, and 1.36 Mg/ha/ yr, respectively, for 0, 5, 10, 15, and 20 years. Samples were collected from three soil depths (0–20, 20–40, and 40–60 cm) …


Morphology Of The Turkey Vagina With And Without An Egg Mass In The Uterus, M. R. Bakst, V. Akuffo Jan 2009

Morphology Of The Turkey Vagina With And Without An Egg Mass In The Uterus, M. R. Bakst, V. Akuffo

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

In this study we examined the gross anatomy of the uterus and vagina in turkeys in egg production. With no uterine egg mass, removal of the tunica serosa that enclosed the uterus revealed deep periodic in-folding of the muscularis transversely circumscribing the sac-like segment. When the connective tissue embracing the neutral buffered formalin fixed vagina was completely teased free, the exposed tubular segment was shaped as a counter-clockwise spiral or as a series of angular, random bends. The uterovaginal junction was flush with the uterine mucosa or projected slightly into the uterine lumen. With a uterine egg mass, the deep …


2009 Across-Breed Epd Table, Larry Kuehn, Mark Thallman Jan 2009

2009 Across-Breed Epd Table, Larry Kuehn, Mark Thallman

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

The table of adjustment factors to be used to estimate across-breed expected progeny differences (AB-EPDs) for eighteen breeds was presented at the Beef Improvement Federation Annual Meeting in Sacramento, CA on May 2 (see attached Table 1). Across-breed adjustment factors have been calculated for growth traits and maternal milk since 1993. Adjustment factors for carcass traits have been calculated since 2008; to be included, breeds must have carcass data in the U.S. Meat Animal Research Center (USMARC) database and report their carcass EPDs on an actual carcass basis using an age-adjusted endpoint. Bulls of different breeds can be compared on …


A Whole-Genome Assembly Of The Domestic Cow, Bos Taurus, Aleksey V. Zimin, Arthur L. Delcher, Liliana Florea, David R. Kelley, Michael C. Schatz, Daniela Puiu, Finnian Hanrahan, Geo Pertea, Curtis P. Van Tassell, Tad S. Sonstegard, Guillaume Marçais, Michael Roberts, Poorani Subramanian, James A. Yorke, Steven. L Salzberg Jan 2009

A Whole-Genome Assembly Of The Domestic Cow, Bos Taurus, Aleksey V. Zimin, Arthur L. Delcher, Liliana Florea, David R. Kelley, Michael C. Schatz, Daniela Puiu, Finnian Hanrahan, Geo Pertea, Curtis P. Van Tassell, Tad S. Sonstegard, Guillaume Marçais, Michael Roberts, Poorani Subramanian, James A. Yorke, Steven. L Salzberg

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

Background: The genome of the domestic cow, Bos Taurus, was sequenced using a mixture of hierarchical and whole-genome shotgun sequencing methods.

Results: We have assembled the 35 million sequence reads and applied a variety of assembly improvement techniques, creating an assembly of 2.86 billion base pairs that has multiple improvements over previous assemblies: it is more complete, covering more of the genome; thousands of gaps have been closed; many erroneous inversions, deletions, and translocations have been corrected; and thousands of single-nucleotide errors have been corrected. Our evaluation using independent metrics demonstrates that the resulting assembly is substantially more accurate …


Effects Of Spontaneous Heating On Fiber Composition, Fiber Digestibility, And In Situ Disappearance Kinetics Of Neutral Detergent Fiber For Alfalfa-Orchardgrass Hays, W. K. Coblentz, P. C. Hoffman Jan 2009

Effects Of Spontaneous Heating On Fiber Composition, Fiber Digestibility, And In Situ Disappearance Kinetics Of Neutral Detergent Fiber For Alfalfa-Orchardgrass Hays, W. K. Coblentz, P. C. Hoffman

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

During 2006 and 2007, forages from 3 individual hay harvests were utilized to assess the effects of spontaneous heating on concentrations of fiber components, 48-h neutral detergent fiber (NDF) digestibility (NDFD), and in situ disappearance kinetics of NDF for large-round bales of mixed alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.). Over the 3 harvests, 96 large-round bales were made at preset bale diameters of 0.9, 1.2, or 1.5 m, and at moisture concentrations ranging from 9.3 to 46.6%. Internal bale temperatures were monitored daily during an outdoor storage period, reaching maxima (MAX) of 77.2°C and 1,997 heating degree …


Efficiency And Establishment Of Three Introduced Parasitoids Of The Mealybug Paracoccus Marginatus (Hemiptera: Pseudococcidae), Kaushalya G. Amarasekare, Catharine M. Mannion, Nancy D. Epsky Jan 2009

Efficiency And Establishment Of Three Introduced Parasitoids Of The Mealybug Paracoccus Marginatus (Hemiptera: Pseudococcidae), Kaushalya G. Amarasekare, Catharine M. Mannion, Nancy D. Epsky

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

Three introduced parasitoids Acerophagus papayae, Anagyrus loecki, and Pseudleptomastix mexicana of the mealybug Paracoccus marginatus have been released in Miami-Dade and Broward counties (Florida) in 2003. Efficiency and establishment of these previously introduced parasitoids to control P. marginatus were measured in 2005 and 2006, at three locations in Homestead (Miami-Dade). Mealybug populations were initially established on three branches (per plant) of 10 hibiscus plants inside closed-sleeve cages. The three treatments, closed, open, and no-cage environments were applied to the three established mealybug populations on each plant. The number of mealybugs and natural enemies was monitored in all treatments. …


Expression And Functional Characterization Of The Plant Antimicrobial Snakin-1 And Defensin Recombinant Proteins, Natalia Kovalskaya, Rosemarie W. Hammond Jan 2009

Expression And Functional Characterization Of The Plant Antimicrobial Snakin-1 And Defensin Recombinant Proteins, Natalia Kovalskaya, Rosemarie W. Hammond

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

In this study, for the first time, functionally active, recombinant, cysteine-rich plant proteins snakin-1 (SN1) and defensin (PTH1) were expressed and purified using a prokaryotic expression system. The overall level of antimicrobial activities of SN1 and PTH1 produced in Escherichia coli was commensurate with that of the same proteins previously obtained from plant tissues. Both proteins exhibited strong antibacterial activity against the phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus (50% inhibitory concentration (IC50) 1.5–8 lM) and antifungal activity against the phytopathogenic fungi Colletotrichum coccoides and Botrytis cinerea (IC50 5–14 lM). Significantly weaker activity was observed against Pseudomonas syringae …


Flight Phenology Of Male Cactoblastis Cactorum (Lepidoptera: Pyralidae) At Different Latitudes In The Southeastern United States, Stephen D. Hight, James E. Carpenter Jan 2009

Flight Phenology Of Male Cactoblastis Cactorum (Lepidoptera: Pyralidae) At Different Latitudes In The Southeastern United States, Stephen D. Hight, James E. Carpenter

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

Long term trapping studies of the invasive moth Cactoblastis cactorum (Berg) were conducted at various latitudes from Puerto Rico to South Carolina. Three flight periods per year were identified at the 5 temperate sites studied, which covered the majority of the infested range on mainland United States. In general, the 3 flight periods across a latitudinal gradient from south Florida to central, coastal South Carolina were a spring flight during Feb-May, a summer flight during Jun-Aug, and a fall flight during Sep-Nov. At any 1 site, each flight period lasted about 2 months. In the tropical areas of the Florida …


Multiplex Real-Time Pcr For Detection, Identification And Quantification Of ‘Candidatus Liberibacter Solanacearum’ In Potato Plants With Zebra Chip, Wenbin Li, Jorge A. Abad, Ronald D. French-Monar, John Rascoe, Aimin Wen, Neil C. Gudmestad, Gary A. Secor, Ing-Ming Lee, Yongping Duan, Laurene Levy Jan 2009

Multiplex Real-Time Pcr For Detection, Identification And Quantification Of ‘Candidatus Liberibacter Solanacearum’ In Potato Plants With Zebra Chip, Wenbin Li, Jorge A. Abad, Ronald D. French-Monar, John Rascoe, Aimin Wen, Neil C. Gudmestad, Gary A. Secor, Ing-Ming Lee, Yongping Duan, Laurene Levy

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

The new Liberibacter species, ‘Candidatus Liberibacter solanacearum’ (Lso) recently associated with potato/tomato psyllid-transmitted diseases in tomato and capsicum in New Zealand, was found to be consistently associated with a newly emerging potato zebra chip (ZC) disease in Texas and other southwestern states in the USA. A species-specific primer LsoF was developed for both quantitative real-time PCR (qPCR) and conventional PCR (cPCR) to detect and quantify Lso in infected samples. In multiplex qPCR, a plant cytochrome oxidase (COX)-based probe-primer set was used as a positive internal control for host plants, which could be used to reliably access the DNA extraction …


Host Range Of Tetramesa Romana Walker (Hymenoptera: Eurytomidae), A Potential Biological Control Of Giant Reed, Arundo Donax L. In North America, John A. Goolsby, Patrick Moran Jan 2009

Host Range Of Tetramesa Romana Walker (Hymenoptera: Eurytomidae), A Potential Biological Control Of Giant Reed, Arundo Donax L. In North America, John A. Goolsby, Patrick Moran

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

The eurytomid wasp, Tetramesa romana Walker was evaluated as a potential biological control agent of the invasive reed grass, Arundo donax in North America. No-choice tests and timed behavioral studies were used to determine the fundamental host range of two genotypes of the wasp collected from Granada, Spain and Perpignan, France. Thirty-five species, including two genotypes of A. donax and seven ecotypes of Phragmites australis, along with closely related grasses, economic grasses and habitat associates were tested. Complete development of both T. romana genotypes was restricted to A. donax and Arundo formosana. The mean number of offspring produced …


Open Field Host Selection And Behavior By Tamarisk Beetles (Diorhabda Spp.) (Coleoptera: Chrysomelidae) In Biological Control Of Exotic Saltcedars (Tamarix Spp.) And Risks To Non-Target Athel (T. Aphylla) And Native Frankenia Spp., Patrick J. Moran, C. Jack Deloach, Tom L. Dudley, Joaquin Sanabria Jan 2009

Open Field Host Selection And Behavior By Tamarisk Beetles (Diorhabda Spp.) (Coleoptera: Chrysomelidae) In Biological Control Of Exotic Saltcedars (Tamarix Spp.) And Risks To Non-Target Athel (T. Aphylla) And Native Frankenia Spp., Patrick J. Moran, C. Jack Deloach, Tom L. Dudley, Joaquin Sanabria

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

Biological control of invasive saltcedars (Tamarix spp.) in the western U.S. by exotic tamarisk leaf beetles, Diorhabda spp., first released in 2001 after 15 years of development, has been successful. In Texas, beetles from Crete, Greece were first released in 2004 and are providing control. However, adults alight, feed and oviposit on athel (Tamarix aphylla), an evergreen tree used for shade and as a windbreak in the southwestern U.S. and México, and occasionally feed on native Frankenia spp. plants. The ability of tamarisk beetles to establish on these potential field hosts was investigated in the field. In …


Field Assessment Of Host Plant Specificity And Potential Effectiveness Of A Prospective Biological Control Agent, Aceria Salsolae, Of Russian Thistle, Salsola Tragus, Lincoln Smith, Massimo Cristofaro, Enrico De Lillo, Rosita Monfreda, Alessandra Paolini Jan 2009

Field Assessment Of Host Plant Specificity And Potential Effectiveness Of A Prospective Biological Control Agent, Aceria Salsolae, Of Russian Thistle, Salsola Tragus, Lincoln Smith, Massimo Cristofaro, Enrico De Lillo, Rosita Monfreda, Alessandra Paolini

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

The eriophyid mite, Aceria salsolae de Lillo and Sobhian, is being evaluated as a prospective classical biological control agent of invasive alien tumbleweeds, including Salsola tragus, S. collina, S. paulsenii and S. australis, in North America. Previous laboratory experiments to determine the host specificity of the mite indicated that it could sometimes persist and multiply on some nontarget plants, including Bassia hyssopifolia and B. scoparia. These are both European plants whose geographic range overlaps that of the mite, but the mite has never been observed on them in the field. A field experiment was conducted in …


Differential Induction Of Redox Sensitive Extracellular Phenolic Amides In Potato, C. Jacyn Baker, Bruce D. Whitaker, Norton M. Mock, Clifford P. Rice, Daniel P. Roberts, Kenneth L. Deahl, Peter P. Ueng, Andrey A. Aver’Yanov Jan 2009

Differential Induction Of Redox Sensitive Extracellular Phenolic Amides In Potato, C. Jacyn Baker, Bruce D. Whitaker, Norton M. Mock, Clifford P. Rice, Daniel P. Roberts, Kenneth L. Deahl, Peter P. Ueng, Andrey A. Aver’Yanov

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

This study focuses on the differential induction of extracellular phenolic amides that accumulate in potato cell suspensions during the first few hours of the interaction between these plant cells and either bacterial pathogens or pathogen-related elicitors. Using suspension cells of Solanum tuberosum we identified 4 hydroxycinnamic acid amides that accumulate in the extracellular environment. Treatment of the suspension cells with pathovars of the plant pathogens Pseudomonas syringae or Ralstonia solanacearum or with pathogen-related elicitors changed the composition of the extracellular phenolic amides within hours and the composition differed for each treatment. Some of the phenolic amides were sensitive to oxidative …


Where To Sample? Ecological Implications Of Sampling Strata In Determining Abundance And Impact Of Natural Enemies Of The Coffee Berry Borer, Hypothenemus Hampei, Juliana Jaramillo, Adenirin Chabi-Olaye, Christian Borgemeister, Charles Kamonjo, Hans-Michael Poehling, Fernando E. Vega Jan 2009

Where To Sample? Ecological Implications Of Sampling Strata In Determining Abundance And Impact Of Natural Enemies Of The Coffee Berry Borer, Hypothenemus Hampei, Juliana Jaramillo, Adenirin Chabi-Olaye, Christian Borgemeister, Charles Kamonjo, Hans-Michael Poehling, Fernando E. Vega

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

Several parasitoids of African origin have been introduced to coffee producing areas of the Americas and Asia as biological control agents of the coffee berry borer (CBB) Hypothenemus hampei (Coleoptera: Curculionidae). These parasitoids have become established in the field but their effect on the CBB has been limited. A two-year field study in Western Kenya has found Prorops nasuta (Hymenoptera: Bethylidae) to be the predominant parasitoid emerging from CBB-infested coffee berries collected on coffee trees or from the ground. P. nasuta comprises more than 75% of the total natural enemies collected. The density of P. nasuta was 90% higher in …


Coccinellidae As Predators Of Mites: Stethorini In Biological Control, David J. Biddinger, Donald D. Weber, Larry A. Hull Jan 2009

Coccinellidae As Predators Of Mites: Stethorini In Biological Control, David J. Biddinger, Donald D. Weber, Larry A. Hull

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

The Stethorini are unique among the Coccinellidae in specializing on mites (principally Tetranychidae) as prey. Consisting of 90 species in two genera, Stethorus and Parasthethorus, the tribe is practically cosmopolitan. The Stethorini are found in a diverse range of habitats, including many agricultural systems such as pome and stone fruits, brambles, tree nuts, citrus, avocadoes, bananas, papaya, palms, tea, cassava, maize, strawberries, vegetables, and cotton, as well as ornamental plantings, grasslands, forests, and heathlands. Tetranychid mite outbreaks became common in many agricultural systems only after World War II, when widespread use of broad-spectrum insecticides increased. Stethorini were initially appreciated …


Visualization Of Biomass Solubilization And Cellulose Regeneration During Ionic Liquid Pretreatment Of Switchgrass, Seema Singh, Blake A. Simmons, Kenneth P. Vogel Jan 2009

Visualization Of Biomass Solubilization And Cellulose Regeneration During Ionic Liquid Pretreatment Of Switchgrass, Seema Singh, Blake A. Simmons, Kenneth P. Vogel

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

Auto-fluorescent mapping of plant cell walls was used to visualize cellulose and lignin in pristine switchgrass (Panicum virgatum) stems to determine the mechanisms of biomass dissolution during ionic liquid pretreatment. The addition of ground switchgrass to the ionic liquid 1-n-ethyl-3-methylimidazolium acetate resulted in the disruption and solubilization of the plant cell wall at mild temperatures. Swelling of the plant cell wall, attributed to disruption of inter- and intramolecular hydrogen bonding between cellulose fibrils and lignin, followed by complete dissolution of biomass, was observed without using imaging techniques that require staining, embedding, and processing of biomass. Subsequent …


Determination By Hplc Fluorescence Analysis Of The Natural Enantiomers Of Sex Pheromones In The New World Screwworm Fly, Cochliomyia Hominivorax, K. Akasaka, D. A. Carlson, T. Ohtaka, H. Ohrui, K. Mori, D. R. Berkebile Jan 2009

Determination By Hplc Fluorescence Analysis Of The Natural Enantiomers Of Sex Pheromones In The New World Screwworm Fly, Cochliomyia Hominivorax, K. Akasaka, D. A. Carlson, T. Ohtaka, H. Ohrui, K. Mori, D. R. Berkebile

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

Bioassays of six racemic synthesized candidate sex pheromone compounds against male New World screwworm Cochliomyia hominivorax (Coquerel) flies showed that the most potent bioactivity was found with 6-acetoxy-19-methylnonacosane and 7-acetoxy-15-methylnonacosane compared with four other isomeric acetoxy nonacosanes and a larger aliphatic ketone. As all these methyl-branched compounds have two asymmetric carbons and four possible enantiomers, characterization of the natural enantiomers was essential. All four enantiomers for the two most bioactive isomers of the natural sex pheromone were synthesized for bioassay. Hydrolysis and derivatization of these enantiomers with different fluorescent reagents was followed by columnswitched high-performance liquid chromatography. The use of …


Comparison Of Passive And Active Canopy Sensors For The Estimation Of Vine Biomass Production, Stamatis Stamatiadis, Dimitris Taskos, Eleftheria Tsadila, Calliopi Christofides, Christos Tsadilas, James S. Schepers Jan 2009

Comparison Of Passive And Active Canopy Sensors For The Estimation Of Vine Biomass Production, Stamatis Stamatiadis, Dimitris Taskos, Eleftheria Tsadila, Calliopi Christofides, Christos Tsadilas, James S. Schepers

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

Recent advances in optical designs and electronic circuits have allowed the transition from passive to active proximal sensors. Instead of relying on the reflectance of natural sunlight, the active sensors measure the reflectance of modulated light from the crop and so they can operate under all lighting conditions. This study compared the potential of active and passive canopy sensors for predicting biomass production in 25–32 randomly selected positions of a Merlot vineyard. Both sensors provided estimates of the normalized difference vegetation index (NDVI) from a nadir view of the canopy at veraison that were good predictors of pruning weight. Although …


Should The Mirid, Eccritotarsus Catarinensis (Heteroptera: Miridae), Be Considered For Release Against Water Hyacinth In The United States Of America?, Julie A. Coetzee, Marcus J. Byrne, Martin P. Hill, Ted D. Center Jan 2009

Should The Mirid, Eccritotarsus Catarinensis (Heteroptera: Miridae), Be Considered For Release Against Water Hyacinth In The United States Of America?, Julie A. Coetzee, Marcus J. Byrne, Martin P. Hill, Ted D. Center

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

Between one and seven biological control agents have been released against water hyacinth (Eichhornia crassipes (Mart.) Solms) in at least 30 countries, with varied success. A mirid, Eccritotarsus catarinensis (Carvalho) (Heteroptera: Miridae), the most recent agent released, is damaging to the plant on the African continent.


Primary Productivity And Water Balance Of Grassland Vegetation On Three Soils In A Continuous Co2 Gradient: Initial Results From The Lysimeter Co2 Gradient Experiment, Philip A. Fay, Alexia M. Kelley, Andrew C. Procter, Dafeng Hui, Virgina L. Jin, Robert B. Jackson, Hyrum B. Johnson, H. Wayne Polley Jan 2009

Primary Productivity And Water Balance Of Grassland Vegetation On Three Soils In A Continuous Co2 Gradient: Initial Results From The Lysimeter Co2 Gradient Experiment, Philip A. Fay, Alexia M. Kelley, Andrew C. Procter, Dafeng Hui, Virgina L. Jin, Robert B. Jackson, Hyrum B. Johnson, H. Wayne Polley

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

Field studies of atmospheric CO2 effects on ecosystems usually include few levels of CO2 and a single soil type, making it difficult to ascertain the shape of responses to increasing CO2 or to generalize across soil types. The Lysimeter CO2 Gradient (LYCOG) chambers were constructed to maintain a linear gradient of atmospheric CO2 (~250 to 500 µ 1-1) on grassland vegetation established on intact soil monoliths from three soil series. The chambers maintained a linear daytime CO2 gradient from 263 µ 1-1 at the subambient end of the gradient to 502 …


Leaf Isoprene Emission Rate As A Function Of Atmospheric Co2 Concentration, Michael J. Wilkinson, Russell K. Monson, Nicole Trahan, Stanfield Lee, Erin Brown, Robert B. Jackson, H. Wayne Polley, Philip A. Fay, Ray Fall Jan 2009

Leaf Isoprene Emission Rate As A Function Of Atmospheric Co2 Concentration, Michael J. Wilkinson, Russell K. Monson, Nicole Trahan, Stanfield Lee, Erin Brown, Robert B. Jackson, H. Wayne Polley, Philip A. Fay, Ray Fall

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

There is considerable interest in modeling isoprene emissions from terrestrial vegetation, because these emissions exert a principal control over the oxidative capacity of the troposphere.