Life Sciences Commons^™

The Influence Of At-Planting Insecticide Treatments On Tobacco Thrips, (Thysanoptera:Thripidae), And Reniform Nematode, (Tylenchida:Hoplolaimidae), In Conventional And Thryvon Cotton Systems, Walker Brett Farmer

Theses and Dissertations

One of the objectives of this research was to evaluate the need for an additional imidacloprid seed treatment on ThryvOn^® (Bayer Crop Science^®, St. Louis, MO) cotton to effectively manage tobacco thrips, Frankliniella fusca (Hinds). While evaluating thrips densities and damage ratings, ThryvOn cotton continued to display reduced damage and thrips populations than non-ThryvOn. Thrips populations and damage ratings were consistently reduced when incorporating a higher rate of imidacloprid, but they were not reduced enough to justify the higher rates of imidacloprid. Another objective of this research was to evaluate the impact of aldicarb (AgLogic Chemical^{® …}

Insights Into The Challenges Posed By Climate Change And Land Competition To Brazil’S Midwest Pulpwood Market, Roberto Hajime Sant Anna Kimura

Theses and Dissertations

I investigated the effect of climate change in one of the few expanding markets in the world in Brazil. In the last decades the demand for pulpwood increased from zero to 11 million tons, leading to an expansion of 700 thousand hectares of Eucalyptus plantation. In 2024, a new mill will start operating increasing the consumption of wood fiber by 8.2 million tons (+49%). I used mathematical programming to investigate how different scenarios of productivity and land will affect the market. My results showed that around 946,000 hectares (+124%) of additional timberland will be necessary in the upcoming decades. The …

Growth Rates, Morphology, And Potential For Mariculture Of The Southern Population Of Crassostrea Virginica In The Lower Laguna Madre, Texas, Jerad Lee Fuelling

Theses and Dissertations

The Eastern Oyster also known as Crassostrea virginica, is an important resource here in the United States. Historically, this species has been overfished, poorly managed, and plagued by disease. Oyster mariculture is a growing industry here in the United States and is a sustainable solution to producing oysters. Texas has become the last coastal state to legalize oyster mariculture which means there is now a vast coastline with many unique bay systems that are open to this industry. One bay system that is particularly unique is the Lower Laguna Madre which is a hypersaline lagoon. Little is known about …

Isolation And Culture Of Epichloё For Reinfection Of Endophyte-Free Southeastern Wildrye (Elymus Glabriflorus), Bryna Joann Haile

Theses and Dissertations

Mutualistic relationships between endophytic fungi and grasses have shown to improve the hardiness of the host. This relationship is common in grasses, including North American native grasses that are important in both forage and grassland ecosystems. Elymus species, such as Canada wildrye (CWR), commonly host the endophytic fungi, Epichloё, while southeastern wildrye (SEWR) may not. In this study, seed of CWR and seed and leaves from local SEWR were assessed for endophyte infection. Infection status was confirmed via histological analysis of seed squashes and leaf peels. Presence/absence of endophyte was determined by scanning for mycelia within seed and between leaf …

Pre-Emergence Herbicide Programs For Weed Control In Soybean (Glycine Max) And The Effect Of Rainfall Amount On Herbicide Activity, Caleb Knox Meyer

Theses and Dissertations

Preemergence (PRE) herbicides are used to control weeds and reduce pressure on postemergence (POST) herbicides. However, knowledge of length of control each herbicide provides, as well as the amount of activation rainfall required for adequate weed control, is unknown in Mississippi soybean production. Twenty-one PRE applied soybean herbicides were evaluated for their duration of residual control for five weeks over twelve site years on three weed species from 2021-2022. Some differences in control following herbicide application used on certain weed species were observed at different times. However, most PRE herbicides resulted in adequate (greater than or equal to 90%) control …

Integrating Weed-Suppressive Cotton Chromosome Substitution Lines And Cover Crops For Sustainable Weed Management In Cotton Production Systems., Alyssa Lea Miller

Theses and Dissertations

Weeds pose a challenge to cotton production, and herbicides have been the primary means of control. However, there is growing concern over weed resistance to herbicides. To address this issue, we evaluated three cover crop species and six cotton accessions for weed suppression. The study found that hairy vetch, wheat, and B16 cotton CS line effectively suppressed Amaranthus species, while MNTN 4-15, B16, hairy vetch, and wheat were correlated with the highest cotton yield. Cover crops were also analyzed for chlorogenic acid content, with wheat, MNTN 4-15, and hairy vetch producing the highest amounts. The greenhouse tray study showed that …

Evaluating The Role Of The Bovine Vaginal Microbiome In Neonatal And Maternal Health Outcomes, Riley D. Messman

Theses and Dissertations

The dam vaginal microbiota is the first major microbial inoculating community within the neonate. The composition of the dam vaginal microbiota has implications in calf commensal microbiota development. Alterations of the dam microbial community prior to parturition could alter inoculating communities and immune responses in both the dam and calf. Thus, authors aimed to elucidate the microbial community composition of the bovine dam vaginal and calf nasal microbiota post-partum after utilizing betadine lavages (BL). The dam vaginal and calf nasal microbial communities and immune responses were evaluated at 0-, 15-, 30- and 60-day post-partum. Microbiota composition of the dam haircoat, …

Upland Cotton And Nematodes: An Analysis Of Historical Resistance, Upcoming Threats, And Co-Inoculation Effects, Amanda Gaudin

Theses and Dissertations

Upland cotton (Gossypium hirsutum ) is an important fiber crop grown throughout the southern United States. Plant-pathogenic nematodes are worm-like animals that feed on the roots of most agronomic crops, including cotton. The southern root-knot nematode (Meloidogyne incognita, RKN) and the reniform nematode (Rotylenchulus reniformis, RN) cause significant yield losses in cotton every year. Current sources of resistance are effective but limited, therefore historical screenings of cotton accessions were revisited in search for novel resistance sources. None were identified but many of the screened accessions possessed markers of known root-knot nematode and reniform nematode resistance. …

Tamaulipan Thornforest Restoration: Factors Influencing Restoration Outcomes And Impacts Of Cover Crops During Replanting, Jerald Thomas Garrett

Theses and Dissertations

Though the rate of deforestation has slowed in recent years, it remains a primary cause of land cover change within forest ecosystems. The Lower Rio Grande Valley, Texas (LRGV) has lost nearly 95% of its native thornforest since the early 1900’s due to agricultural and urban expansion. The focus of this study is to assess the current vegetative state of restored thornforest sites located in the eastern LRGV and to evaluate the use of cover crops during replanting of native seedlings. Our assessment of restored thornforest sites revealed actively restored sites demonstrated higher overall averages of richness, abundance, and diversity …

Soil Moisture Dynamics In Cover Cropping Systems: From Local To Global Scales, Manish Gautam

Theses and Dissertations

Cover cropping systems, which have gained recognition for their ability to enhance soil health and promote sustainability are also associated with potential risks related with declining soil moisture and pose a dilemma for farmers considering the adoption of cover crops in water deficit semi-arid settings worldwide. To address this pressing issue, we conducted a participatory cover cropping trial in the Lower Rio Grande Valley (LRGV) region, encompassing four different farms and supplemented this experiment with a meta-analysis to answer our soil moisture and climate parameters and quantify the impact of cover crops on soil moisture levels. The findings revealed that …

Cover Crops Influence Arthropod Community Dynamics Through Seasonal Variation And Cascading Effects, Adegboyega Fajemisin

Theses and Dissertations

Chapter 1: This chapter gives an overview of how cover crops influence soil’s physical, chemical, and biological properties, and their role on mediating arthropod community dynamics with implications for pest management in the subsequent cash crop.

Chapter 2: This chapter examines the effects of cover-cash crop rotation on arthropod community dynamics on four growers fields in the Lower Rio Grande Valley, Texas. We assessed the impact of cover crops planted in the summer months on the subsequent cash crops planted in the winter. Our results showed that cover crops had a differential effect on the population of beneficials and herbivores …

Nutrient Optimization For Vegetable Production Under Decoupled Aquaponics Using Brackish Water, Salma Walid Hany Ahmed Abdelfattah

Theses and Dissertations

As the world moves to more sustainable agriculture methods in the agribusiness industry, decoupled aquaponics is recognized as one of the newest techniques currently being utilized to achieve more local food security. As the topic is still freshly new within the industry, a finite number of publications and studies have been made that address the topic hands-on with its many variables. Subsequently, in this paper, an experiment was conducted to assess the most optimized production conditions of both lacinato kale (Brassica oleracea var.palmifolia) and Swiss chard Bright Light (Beta vulgaris ssp. Cicla var. flavescens) plants through the utilization of a …

Evaluation Of Italian Ryegrass And Palmer Amaranth Control In Mississippi, Johnson Harris Hughes

Theses and Dissertations

Italian ryegrass is a problematic weed in Mississippi corn production due to the development and proliferation of glyphosate resistance. Studies were conducted to assess Italian ryegrass control prior to planting using herbicides. Effects of fall and spring applied burndown herbicide applications for Italian ryegrass control and subsequent corn grain yield were investigated at the R.R. Foil PSRC in Starkville, MS, at the Coastal Plain Experiment Station in Newton, MS, and the Black Belt Experiment Station in Brooksville, MS on soil textures ranging from sandy loam to silt clay loam. A fall preemergence (PRE) application of S-metolachlor + metribuzin followed …

Genome-Wide Association Study For Agronomic Traits In Bermudagrass (Cynodon Spp.), Lovepreet Singh

Theses and Dissertations

Bermudagrass (Cynodon spp.) breeding and cultivar development is hampered by limited information regarding its genetic and phenotypic diversity. A germplasm collection of 206 bermudagrass accessions from 29 countries was genotyped with high-throughput genotyping-by-sequencing technique. Genomic diversity in this diverse germplasm panel was assessed with multifaceted approaches including population structure, phylogenetic analysis, principal component analysis, and genetic diversity parameters. This study revealed substantial genetic variation in the Cynodon accessions, demonstrating the potential of this germplasm panel for further genetic studies and cultivar development in breeding programs. Another critical issue in turfgrass breeding is the lack of information regarding the genetic …

Marginal Agricultural Land Identification In The Lower Mississippi Alluvial Valley, Prakash Tiwari

Theses and Dissertations

This study identified marginal agricultural lands in the Lower Mississippi Alluvial Valley using crop yield predicting models. The Random Forest Regression (RFR) and Multiple Linear Regression (MLR) models were trained and validated using county-level crop yield data, climate data, soil properties, and Normalized Difference Vegetation Index (NDVI). The RFR model outperformed MLR model in estimating soybean and corn yields, with an index of agreement (d) of 0.98 and 0.96, Nash-Sutcliffe model efficiency (NSE) of 0.88 and 0.93, and root mean square error (RMSE) of 9.34% and 5.84%, respectively. Marginal agricultural lands were estimated to 26,366 hectares using cost and sales …

Activity Level Of Helicoverpa Armigera Nucleopolyhedrovirus (Hearnpv) And Feeding Habits Of Helicoverpa Zea Larvae After Ingestion Of Hearnpv In Mississippi Soybean, Judge Tyler Fortenberry

Theses and Dissertations

HearNPV was applied to a soybean field and evaluated for residual efficacy at different time intervals (0, 12, 24, 36, 48, and 72 hours) after application in laboratory bioassays with treated leaves. Larval mortality was rated at five, seven and twelve days after larval infestation. Larval mortality increased as the number of days after infestation increased. To evaluate the feeding habits of Helicoverpa zea at the 2^nd and 3^rd instar, HearNPV exposed larvae and untreated larvae were weighed at zero (before diet exposure), four, and seven days. At four days after exposure, larval weight gain of …

Sweet Potato In The Lower Rio Grande Valley: Evaluating Performance Across Several Cultivars, Jon Dale

Theses and Dissertations

In Texas’ subtropical, semiarid Lower Rio Grande Valley (LRGV), citrus and sugarcane cultures have dominated specialty crop production for more than a half-century. However, the future of these high-dollar crops is becoming uncertain with increases in exotic pathogens, intensifying urbanization and the overarching complexities of both climate change and binational governance of Rio Grande Basin waters. For these reasons, the region’s specialty crop sector needs to be ready for alternatives that could benefit both market outlets and reduced input dependencies. Sweet potato (Ipomoea batatas), commercially grown in various similar climates worldwide with limited water resources, could be one …

Growing The Future Of Agriculture: An Examination Of Knowledge-Sharing And Community Building In The Fresh Produce And Floral Council, Oscar Guzman

Theses and Dissertations

This study examines knowledge-sharing practices within a community of practice (CoP) through a case study of the Fresh Produce and Floral Council (FPFC). The study sought to investigate how the FPFC promoted agricultural knowledge and expertise, impacted its members' social relationships and knowledge-sharing practices, communicated clear roles and expectations, and provided valuable and accessible resources. A mixed-methods approach was employed to investigate the research questions, which involved conducting a survey and utilizing descriptive statistics, frequencies, and Spearman correlations to analyze both the Likert scale and open-ended responses. The findings suggested that the FPFC has a knowledge-sharing culture promoting active participation …

Evaluation Of Warm Season Vegetables Using Sustainable Production Practices, Jacob Arthur

Theses and Dissertations

Sustainable practices were evaluated for the production of two warm season vegetable crops, tomato and chile peppers. The first study investigated the plant vegetative growth, fruit production timing, yield components and fruit quality of three hybrid and three heirloom tomato cultivars grown in a high tunnel using grafted and non-grafted plants. Grafting the selected tomato cultivars with the two rootstock types did not alter total marketable yield of any cultivar, but affected overall stem diameter, fruit color, and β-carotene concentrations of tested tomato cultivars. The second study evaluated the plant growth, yield, and fruit quality of nine heirloom chile pepper …

Metagenomic Analysis Of Root-Associated Microbiome Of Healthy And Taproot Decline-Affected Soybeans And Identification Of Healthy Soybean Root Endophytes With Protective Activity Against The Causal Agent, Xylaria Necrophora, Uyen Wesser

Theses and Dissertations

Plant roots are associated with a diverse microbial community of bacteria and fungi. The root microbiome communities associate with the root surface or penetrate the superficial layers of root tissues. It is of high agronomic interest to characterize root microbiomes and identify microbes with beneficial effects on plant defense against pathogens. Soybean taproot decline (TRD) is an emerging soil-borne disease caused by a fungus classified as Xylaria necrophora, challenging to control and with devastating effects on yield. Our group has initiated a study of the soybean root microbiome with three primary experiments: (I) perform a comparative study of root …

United We Stand? Investigating The Impact Of Unified Dues Agreements Between State And National Career & Technical Education (Cte) Professional Organizations On Cte Funding In The Southern States, Justin Ryan Hall

Theses and Dissertations

Career and Technical Education (CTE) teachers have long been active in lobbying the federal and state governments in support of CTE through their professional organizations, but these are not traditionally considered interest groups. This study sought to determine if the formal relationships—dues agreements—between the two largest national professional organizations, and their state affiliates had an impact on state funding for CTE. The impacts of professional organization unity, membership rates, and lobbying expenses on state-level CTE funding were analyzed through the lens of interest group theory, a subfield of political science. Within this population (N = 13), 1) a link …

The Effects Of Glyphosate Salts And Volatility-Reducing Agents (Vra) On Dicamba Volatility, Nicole Glenn

Theses and Dissertations

Dicamba is often tank mixed with glyphosate to increase herbicidal efficacy but may contribute to off-target movement (OTM). In recent years, volatilization has become problematic for dicamba-containing herbicides, resulting in increased regulatory requirements necessitating the use of volatility-reducing agents (VRA) for application. Research was conducted in 2021 and 2022 using low tunnels in a field environment and humidomes in a greenhouse environment to further assess how glyphosate salts and VRAs affect dicamba volatility. Our data indicate that the inclusion of glyphosate to dicamba can increase dicamba volatility, depending on the glyphosate salt used. The inclusion of the evaluated VRAs will …

Evaluation Of Novel Litter Amendments For Use In The Commercial Broiler Industry, Jorge A. Urrutia

Theses and Dissertations

Poultry litter amendments (LA) are commonly used to maintain good litter quality; the most common ones; are acidifiers. However, concern over the lifespan of LA acidifiers (d) and corrosive nature revealed a need for alternative LA. Products of interest include biochar (BC), superabsorbent polymers (SAPs), and alum mud (AM). Experiment 1 was a screening study (n=17 treatments, no birds) conducted to determine the optimal application rate/method of BC, SAPs, and AM vs.commercial LA and a control. Most SAPs treatments measured metrics may be similar (i.e., bacteria, water activity) or better (pH) vs. commercial LA (PLT). High inclusions of novel LA …

An Assessment Of Physical And Microbial Dynamic Properties Sensitive To Tillage Practices In Hidalgo Sandy Clay Loam Soils, Rocio N. Hernandez

Theses and Dissertations

Mechanized tillage is known to impact the dynamic physical, biological and chemical properties of a given soil, and as a result, can cause systematic harm to the soil’s function (Alam et al., 2014). The aim of this study is to assess how a series of land management tillage practices will impact dynamic physical and biological soil health parameters such as aggregation, carbon, respiration, and enzymatic activity (β-glucosidase). According to Acir et al (2020), the aforementioned soil parameters are both co-influenced and dependent, indicating a response to tillage is likely. A total of 198 samples of Hidalgo series soils were collected …

Grapefruit Peel Biochar Applications For Immobilizing Copper And Lead In Soil, Michael Alfredo Navarro

Theses and Dissertations

This study investigated the efficacy of grapefruit peel (GP) derived biochar materials (two pyrolysis temperatures 450°C and 800°C) as a potential adsorbent to immobilize heavy metal (copper and lead) in a local sandy loam clay soil. A batch adsorption test with heavy metal concentrations at 50 mg L-1, and 100 mg L-1 revealed that soil itself had the highest immobilization percentage compared to the GP biochars. A soil column experiment was conducted to determine how much the GP biochar samples and the tested soil will exhibit adsorptive characteristics for heavy metals when 50 ml of 50 mg L-1 copper or …

Weather Parameters Influencing The Incidence Of Citrus Canker Caused By Aw Strain In The Rio Grande Valley, Amit Sharma

Theses and Dissertations

Citrus canker caused by bacterium Xanthomonas citri subsp. citri (Xcc) seriously affects the citrus industry by making the fruit unmarketable due to unsightly lesions on the fruit. Canker caused by Aw strain of Xcc was reported in the citrus trees located in the residential areas of the Rio Grande Valley (RGV). Canker severity differs amongst cultivars/varieties, and it is influenced by prevailing environmental conditions. Multiple regression modeling of the disease incidence with the environmental variables such as temperature, humidity, windspeed, wind gust, and rainfall was performed to understand the environmental conditions that are favorable for spread of citrus …

Dynamic Soil Properties In The Lower Rio Grande Valley: Understanding Responses Of Infiltration Rate, Bulk Density, Aggregate Stability To Different Tillage Practices, Temiloluwa Faith Awotoye

Theses and Dissertations

Dynamic Soil Properties (DSPs) are soil properties that change in response to both natural and human-caused interruptions and pressures such as agro-based and wildland management. These soil properties can transform for months or even years in response to the farm use and management procedures. This research project investigates the relationship between different dynamic soil physical properties and tillage practices in the Texas Hidalgo sandy clay loam benchmark soil series. Data analyses was done to compare the effect of tillage to these soil physical properties and build a discussion about relationships between on-farm practices to other aspects of farm viability. We …

Incorporating Native Plants In Insectary Strips To Promote Insect Diversity And Below-Ground Beneficial Microbes In South Texas, Lindsey N. Richards

Theses and Dissertations

Farm edges are generally the most undisturbed areas in a farm with diverse vegetation and can enhance agrobiodiversity and provide crucial food and shelter for wildlife, insects, and soil biota. Planting native wildflowers with the ability to reseed and withstand local climatic conditions for semi-permanent vegetation around farm edges or in between crops has potential to biologically control pests. To test this, we ran a two-year study and installed three different flowering insectary strips on a certified organic vegetable farm in South Texas during the winter season. The treatments were: 1) a commercially sourced 17-species native wildflower seed mix; 2) …

The Employability Of State Ffa Degree Recipients In Alabama, Kailee D. Johnson

Theses and Dissertations

Many high schools have shifted from comprehensive graduation exams to a focus on College and Career Readiness. A common method used to determine when a student is college and career ready is a Career Readiness Indicator (CRI). Many CRIs demonstrate a benchmark learning goal for students. Among academic-based CRIs are Career and Technical Education (CTE) industry credentials. Credentials are just one way that agriculture classrooms contribute to student success. This study compiled existing research on CRIs and employability skills in CTE students to determine how the State FFA Degree could potentially fit into this category as well as highlight specific …

Effects Of The In Ovo Administration Of The Poulvac E. Coli Vaccine In Layer Hatching Eggs On Hatchability, Hatchling Characteristics, And Early Posthatch Chick Performance, Lauren L. Lindsey

Theses and Dissertations

Avian Pathogenic E. coli can lead to infections in laying hens and wide-spread economic problems in the table egg industry. A vaccine widely used to combat APEC is the Poulvac E. coli vaccine, which is normally applied via spray vaccination. Application of this vaccine via in ovo injection has not been examined. The purpose of this series of studies was to determine the effects of injecting 50 μL of different dosages of the PECV into Hy-Line W-36 layer hatching eggs on the hatchability and characteristics of the hatchlings, and on the livability and characteristics of the chicks through 21 d …