Life Sciences Commons^™

Evaluation Of Soybean [Glycine Max (L.) Merr.] Cultivar Response To Prophylactic Fungicide Application, Steven B. Stoker

Theses and Dissertations

Soybean growers in the southern United States commonly deal with disease issues that can limit yield potential. As a result, growers have adopted prophylactic fungicide application targeted at specific growth stages as a standard management practice. However, yield responses to prophylactic applications have become sporadic over time. One major change that has occurred is adoption of cultivars with improved disease tolerances. Therefore, the objective of this research was to evaluate yield response of cultivars representing multiple genetic backgrounds to fungicides applied prophylactically at the R4 soybean growth stage. Experiments were conducted in 2020 and 2021 to determine the yield impact …

Micronutrient Concentration Effects On Lettuce Growth And Susceptibility To Pythium, Kalyn M. Helms

Graduate Theses and Dissertations

In hydroponic production waterborne pathogens such as Pythium are ubiquitous and continually threaten a wide range of Controlled Environment Agriculture (CEA) crops in hydroponic production, including but not limited to: lettuce, spinach, basil, arugula, cucumber, tomato, sweet pepper, roses, chrysanthemums, and cannabis (Sutton et al., 2006; Gull, 2002; McGehee and Raudales, 2021; Gillespie, 2020). Despite extensive sanitation measures, disease control in hydroponics is fallible and requires constant surveillance and management to minimize outbreaks (Sutton et al., 2006). A potential disease suppression strategy is to increase micronutrient concentrations within hydroponic systems to naturally strengthen plant defenses against pathogens such as Pythium. …

Comparative Genomics And Virulence Studies Of Streptomyces Soil Rot And Scab Pathogen Species, Natasha Soares

LSU Doctoral Dissertations

Comparative genomic analyses were performed to gain insights into the organization and content of the genome of Streptomyces ipomoeae, the soil rot pathogen that infects sweetpotatoes. Unlike Streptomyces scab pathogens, the thaxtomin phytotoxin gene cluster (txt) in S. ipomoeae does not appear to reside within a genomic island and has diverged from its scab pathogen counterparts. Increased usage of the rare TTA codon, particularly for the txt cluster, suggests greater translational control by the bldA tRNA in S. ipomoeae. Orthologous gene searches and secondary metabolite profiling yielded ortholog groups and metabolite gene clusters that were exclusive …

Vegetable Diseases Of Utah, Claudia Nischwitz, Marion Murray, Nick Volesky

All Current Publications

This guide provides a list of vegetable crop diseases that have been documented in Utah along with some that are likely to occur. Plant diseases are caused by pathogens such as fungi, bacteria, viruses, and fungal-like organisms. Diagnosing specific plant diseases takes careful observation of signs, symptoms, and sometimes culturing and molecular testing in a laboratory setting.

Using Uav Technology Paired With Multispectral Cameras To Assess Crown Rust Epidemics In Oats, Turner A. Graham

LSU Master's Theses

Crown rust, caused by Puccinia cornonata f. sp. avenae, is a common disease of oats (Avena sativa) found virtually everywhere oats are cultivated. This disease has caused yield losses of 10 to 40% worldwide. Early detection is important for effective management. A more recently utilized technology in agriculture is unmanned aerial vehicles (UAVs). UAVs, or drones, equipped with cameras are now being used as a resource to take images of fields to identify pests and other issues that may be occurring. Normalized differentiated vegetative index (NDVI) is a numerical indicator used to determine the vegetative health of …

The Virome Of Peony And The Population Structure Of Its Most Prominent Viruses, Cullen Shaffer

Graduate Theses and Dissertations

Peony (Peonia lactiflora, Pall.) is a popular ornamental that has been cultivated for millennia. Due to its popularity, plant material is frequently moved across international borders allowing for the spread of viruses. The virome of several peony plants was investigated and four viruses; namely Amazon lily mild mottle virus (ALiMMV), Cycas necrotic stunt virus (CNSV), Gentian Kobu-sho associated virus (GKaV) and Lychnis mottle virus (LycMoV) were detected for the first time in the Western Hemisphere. Incidence ranged from a few plants for ALiMMV to near universal infection for CNSV. GKaV was found in individuals that were infected with Lemoine’s disease …

Exploration Of Antiviral Effects Of Rna-Dependent Rna Polymerases 3, 4 And 5 In Arabidopsis., Eli R. Kallison, Aleksandra Beric, Blake Meyers

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

Small RNAs play a number of vital roles in plants, including viral resistance. A particular class of small RNA that regulates plant defense from pathogens, among other functions, is known as small interfering RNAs (siRNAs). A key player in the biogenesis pathway of siRNAs are RNA-Dependent RNA Polymerases (RDRs). There are six RDR proteins in Arabidopsis thaliana, three of which have well documented roles (RDRs 1, 2 and 6), and three of which have no documented role. Here, we look at the functions of the unstudied RDRs, RDRs 3, 4 and 5, to see whether they affect antiviral resistance.

Population Structure And Reproductive Biology Of Monilinia Vaccinii-Corymbosi (Reade) Honey In Lowbush Blueberry In Maine, Katherine A. Ashley

Electronic Theses and Dissertations

Lowbush blueberry, Vaccinium angustifolium Aiton, is both an economically and culturally important crop in Maine, being one of the few endemic crops to North America. The fungus Monilinia vaccinii-corymbosi (Mvc) causes mummy berry disease and is a significant pathogen of both highbush (Vaccinium corymbosum) and lowbush blueberries. While impacts of this disease are not regularly documented, it is estimated that 30-50% of the yield in an unmanaged field can be lost because of Mvc. This disease is typically managed with fungicides or burning of the field during years when the field is pruned, however, the impacts to the …

Dissecting The Economic Impact Of Soybean Diseases In The United States Over Two Decades, Ananda Y. Bandara, Dilooshi K. Weerasooriya, Carl A. Bradley, Tom W. Allen, Paul D. Esker

Plant Pathology Faculty Publications

Soybean (Glycine max L. Merrill) is an economically important commodity for United States agriculture. Nonetheless, the profitability of soybean production has been negatively impacted by soybean diseases. The economic impacts of 23 common soybean diseases were estimated in 28 soybean-producing states in the U.S., from 1996 to 2016 (the entire data set consisted of 13,524 data points). Estimated losses were investigated using a variety of statistical approaches. The main effects of state, year, pre- and post-discovery of soybean rust, region, and zones based on yield, harvest area, and production, were significant on “total economic loss” as a function of …

Downy Mildew Of Alfalfa, Claudia Nischwitz

All Current Publications

This fact sheet describes downy mildew, an obligate parasite. It describes symptoms in alfalfa, the disease cycle and how to manage it.

Meta-Analysis Of Yield Response Of Foliar Fungicide-Treated Hybrid Corn In The United States And Ontario, Canada, Kiersten A. Wise, Damon Smith, Anna Freije, Daren S. Mueller, Yuba Kandel, Tom Allen, Carl A. Bradley, Emmanuel Byamukama, Martin Chilvers, Travis Faske, Andrew Friskop, Clayton Hollier, Tamra A. Jackson-Ziems, Heather Kelly, Bob Kemerait, Paul Price Iii, Alison Robertson, Albert Tenuta

Plant Pathology Faculty Publications

Background

Foliar fungicide applications to corn (Zea mays L.) occur at one or more application timings ranging from early vegetative growth stages to mid-reproductive stages. Previous studies indicated that fungicide applications are profitable under high disease pressure when applied during the tasseling to silking growth stages. Few comprehensive studies in corn have examined the impact of fungicide applications at an early vegetative growth stage (V6) compared to late application timings (VT) for yield response and return on fungicide investment (ROI) across multiple locations.

Objective

Compare yield response of fungicide application timing across multiple fungicide classes and calculate the probability …

Elucidating Disease Dynamics In The Biocontrol Of Ailanthus Altissima While Confirming The Host Specificity Of The Vascular Wilt Pathogen Verticillium Nonalfalfae, Kristen L. Wickert

Graduate Theses, Dissertations, and Problem Reports

Ailanthus altissima is a highly invasive exotic tree species entrenched throughout the United States. Since the discovery of a vascular wilt disease of Ailanthus in 2002, caused by the fungus Verticillium nonalfalfae, many studies are investigating its potential as a biocontrol focusing on efficacy, host specificity and disease transmission. This study addresses: the reproductive potential of Ailanthus; if V. dahliae alters Verticillium wilt progression; if hardiness zones influence the individual contributions of two Verticillium spp.; can a unique habitat affect biocontrol efficacy; and can the fungal proteome of V. nonalfalfae allow us to explain differences in host …

Natural Selection For Disease Resistance In Hybrid Poplars Targets Stomatal Patterning Traits And Regulatory Genes., Karl Christian Fetter

Graduate College Dissertations and Theses

The evolution of disease resistance in plants occurs within a framework of interacting

phenotypes, balancing natural selection for life-history traits along a continuum of

fast-growing and poorly defended, or slow-growing and well-defended lifestyles. Plant

populations connected by gene flow are physiologically limited to evolving along a

single axis of the spectrum of the growth-defense trade-off, and strong local selection

can purge phenotypic variance from a population or species, making it difficult to

detect variation linked to the trade-off. Hybridization between two species that have

evolved different growth-defense trade-off optima can reveal trade-offs hidden in either

species by introducing phenotypic and …

Research: South Dakota State University, Spring 2016, Christie Delfanian, Emily Weber

Research: South Dakota State University

CONTENTS:

Genome Researcher investigate impact of L1 jumping genes [Page] 2
CRP funds important resource for hunters [Page] 3
Nurse-researchers help health-care facilities develop, improve tobacco-free policies [Page] 3
MS: Exercise scientist improves movement, quality of life for MS patients [Page] 5
Plant scientists defend South Dakota crops against diseases [Plant] 7
Investigating influenza D virus earns doctoral student scholarship [Page] 9
Steel shavings trap phosphorous, protecting water quality [Page] 10

The Role Of Calcium In Pathogen Defense Responses In The Moss Mnium Cuspidatum, Morgan Blake

Undergraduate Honors Thesis Collection

When exposed to stress, whether that be by pathogen, thermal or weather changes, or other components of the environment, plants employ a variety of defense mechanisms depending on the severity of the stress. When attacked by a pathogen, the moss Mnium cuspidatum utilizes an innate, basal response followed by hypersensitive response (HR) and systemic acquired resistance (SAR). Calcium is known to be involved in signaling cascades that mediate defense responses in other organisms. In the present study, lanthanum nitrate (LaNO3), methoxyerapamil (D600), and ethylene glycol tetraacetic acid (EGTA) were used to inhibit the presence of calcium in M. cuspidatum in …

Pythium: Characterization Of Resistance In Soybean And Population Diversity, Keiddy Esperanza Urrea Romero

Graduate Theses and Dissertations

Pythium spp. are an important group of pathogens causing stand losses in Arkansas soybean production. New inoculation methods and advances in molecular techniques allow a better understanding of cultivar resistance and responses of Pythium communities to cultural practices. The objectives of this research were to i) characterize the resistance of soybean to P. aphanidermatum with two phenotyping assays that evaluated the seed rot phase of the disease; and ii) understand the effect of long term crop rotation on species diversity and iii) to determine the effect of location, temperature and continuous soybean and soybean-rice rotation on Pythium spp. diversity in …

The Pythium Suppressive Ability Of Glomus Intraradices In Cherry Tomato Propagation, Stanley Graham

Biological Sciences

No abstract provided.

Effects Of Iron On Cercospora Leaf Blight Of Soybean, Eduardo Chagas Ferreira Da Silva

LSU Master's Theses

Cercospora leaf blight (CLB) of soybean caused by Cercospora kikuchii is an important disease in Lousiana. Preliminary screening of foliar applications of the micronutrients Fe, Mn, Cu, Zn, B, Mo and Al, showed that Fe decreased CLB severity consistently. The objective of this work was to test the effects of commercial formulations of Fe, Manny Plex Fe and Fe EDTA (Brandt Consolidated, Springfield, IL) on leaf colonization by C. kikuchii, symptom development (blight and purple leaves), and yield. Four rates of Manny Plex Fe and four rates of Fe EDTA were applied to field plots at R5 growth stage. Leaf …

Spatial Distributions Of Rhizoctonia Species In Soybean Fields Undergoing Annual Rotations With Rice, Terry Neil Spurlock

Graduate Theses and Dissertations

Aerial blight is caused by Rhizoctonia solani AG1-IA. This pathogen also causes sheath blight of rice. In Arkansas, many soybean and rice fields undergo an annual rotation of these two crops which facilitates a continuous source of inoculum from one year to the next. Aerial blight is a two stage disease in that R. solani AG1-IA colonizes the plant during the early vegetative growth stages and then aerial blight develops after the soybean canopy closes in the later reproductive stages of development. As a result of the upper portion of the canopy often being asymptomatic, significant yield loss can occur …

G74-108 Wilts Of Cucurbits (Revised October 1994), James R. Steadman, David L. Keith, Laurie Hodges

Laurie Hodges

Discussion covers the symptoms, disease cycles, and control measures for bacterial and Fusarium wilts of cucurbits, including cucumbers, cantaloupe, watermelons, squash, and pumpkins. Wilt caused by squash vine borer also is covered.

Pathogen Induced Hypersensitive Response And Systemic Acquired Resistance In The Moss Amblystegium Serpens, Collin Elliot Bowman

Undergraduate Honors Thesis Collection

The moss Amblystegium serpens and the pathogenic fungus Pythium irregulare were used to study plant-pathogen interactions in a non-vascular plant. The major findings in this report include that P. irregulare does infect A. serpens but entire moss death was not noted, 25°C is the optimum temperature for P. irregulare appressoria formation, most appressoria were found on A. serpens leaves, and the SAR response within A. serpens seems to be reducing the number of P. irregulare penetrated moss cells. Future research on the pathogen defense mechanisms of A. serpens is important and promising. When we elucidate these complex chemical processes in …

Simplicillium Lanosoniveum, A Mycoparasite Of Phakopsora Pachyrhizi And Its Use As A Biological Control Agent, Nicole A. Ward

LSU Doctoral Dissertations

In 2007, a filamentous fungus was recovered from sori of soybean rust (SBR), caused by Phakopsora pachyrhizi, collected from Louisiana and Florida. This fungus was identified as Simplicillium lanosoniveum on the basis of ITS sequence data and morphological traits. Simplicillium lanosoniveum was found coiling within sori and around urediniospores and showed a trophic attraction to rust sori, extending from sorus to sorus. In co-inoculated soybean leaves, the fungus did not grow or establish on leaf surfaces until sori erupted. Similarly, S. lanosoniveum colonized within 3 days and sporulated within 4 days on leaves showing disease symptoms. In field studies, when …

A Comparison Of Soil And Corn Kernel Aspergillus Flavus Populations: Evidence For Niche Specialization, Rebecca Ruth Sweany

LSU Master's Theses

Aspergillus flavus is an opportunistic fungal pathogen that infects peanuts, cotton, corn and tree nuts. Aspergillus flavus is a major problem globally due to the production of acutely toxic and carcinogenic aflatoxins. Louisiana climatic conditions lead to annual threats of corn aflatoxin contamination. The purpose of this study was to determine the specific ability of different strains of A. flavus to infect corn. Five soil samples and 10 corn ears were collected from each of seven corn fields throughout Louisiana. In addition, Francis Deville of Monsanto Company collected 7, 6, 2, and 4 soil samples and corn ears from four …

Plant Health In Private Urban Gardens, Stephan Helfer

Turkish Journal of Botany

Private garden plots present a vast area for growing plants for food or enjoyment. The Royal Botanic Garden Edinburgh provides a plant identification and advisory service to the public. This includes a service to advise on plant health problems, which is not advertised. In the past 17 years a moderate number of individuals made use of this service, with an average of 67 enquiries and some 100 specimens per year. Relevant data from the enquiries were entered into a database and analysed. The majority of enquiries concerned tree problems, followed by ornamental and fruit plant problems. Fungi ranked highest, with …

Rna Polymerase Ii Gene (Rpb2) Encoding The Second Largest Protein Subunit In Phaeosphaeria Nodorum And P. Avenaria, Arkadiusz Malkus, Pi-Fang Linda Chang, Sabina M. Zuzga, Kuang-Ren Chung, Jonathan Shao, Barry M. Cunfer, Edward Arseniuk, Peter P. Ueng

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

A 5586 bp sequence (accession no. DQ278491), which includes the RNA polymerase II gene (RPB2) encoding the second largest protein subunit (RPB2), was obtained from the wheat biotype Phaeosphaeria nodorum (PN-w) by PCR amplification. The 3841 bp full length RPB2 gene contains two exons and a 52 bp intron, and encodes a complete 1262 amino acid protein. Similar to the C-terminals of the b subunits of prokaryotes and yeast RNA polymerases, the deduced RPB2 protein contained many structural features needed for gene transcription. Based on the phylogenetic analysis with the deduced RPB2 polypeptide sequences, the PN-w was closely related to …

Ec05-1894 Dry Bean Disease Profiles Ii: Fungal Root Rot And Wilt Diseases, Robert M. Harveson, John E. Watkins, Loren J. Giesler, Jennifer L. Chaky

University of Nebraska-Lincoln Extension: Historical Materials

This two-page, 4-color publications profiles the fungal root rot and wilt diseases and symptoms of dry bean. These diseases include: fusarium root rot, rhizoctonia root rot, pythium root rot, fusariuim yellows, and white mold.

Ec05-1893 Dry Bean Disease Profiles I: Foliar And Bacterial Diseases, Robert M. Harveson, John E. Watkins, Loren J. Giesler, Jnenifer L. Chaky

University of Nebraska-Lincoln Extension: Historical Materials

This two-page, 4-color publications profiles the foliar and bacterial diseases and symptoms of dry bean. Diseases discussed include: bean common mosaic/bean yellow mosaic virus, rust, common blight, halo blight, brown spot, bacterial wilt.

Nf05-652 Soybean Rust Fungicide Use Guidelines For Nebraska, Loren J. Giesler, John A. Wilson, Jennifer M. Rees

University of Nebraska-Lincoln Extension: Historical Materials

While the impact that soybean rust will have on Nebraska's soybean crop is unknown, producers should be prepared to manage the disease. When soybean rust occurs or is expected to occur shortly in Nebraska, growers can use the decision-aid flow chart on page 2 of this NebFact to determine whether to treat and, if treating, which class of fungicide (chlorothalonil, strobilurin, or triazole) to use.

Nf05-634 Fungicides To Manage Soybean Rust: What Are The Product Differences?, Loren J. Giesler, Thomas J. Weissling

University of Nebraska-Lincoln Extension: Historical Materials

If Nebraska soybean producers find themselves needing to apply a fungicide for soybean rust this year, it will be important to choose an effective product based on the stage of disease development in the specific field. It will be important for all producers and crop managers to be aware of where soybean rust is being detected to pursue a treatment that provides the maximum return on investment for any fungicides being applied.

This NebFact discusses the fungicides available for Nebraska soybean fields and resistance management issues.

Nf05-633 Soybean Rust: How Great Is The Threat For Nebraska?, Loren J. Giesler

University of Nebraska-Lincoln Extension: Historical Materials

Soybean rust is a serious foliar disease that has caused significant crop losses in other parts of the world. It was first detected in the United States in November 2004 and has since been identified in several southeastern states. The fact that wind-borne spores principally spread soybean rust suggests it will be a seasonal problem in Nebraska.

This NebFact discusses the symptoms, life cycle, host range, potential impact on soybean production, and management of soybean rust in the state of Nebraska.