Life Sciences Commons^™

Automated Tree Mortality Detection Using Ubiquitously Available Public Data, Michael T. Huggins

Master's Theses

Understanding the dynamic interplay between fire severity, topography, and tree mortality, is crucial for predicting future forest dynamics and enhancing resilience against climate change-induced wildfire regimes. This thesis develops a multi-sensor approach for automated estimation of tree mortality, then applies it to examine trends in tree mortality over a six-year period across a fire affected study site in the Trinity River basin in Northern California. The Random Forest model uses publicly available USGS 3D Elevation Program Lidar (3DEP) and NAIP imagery as inputs and is likely to be easily adaptable to other landscapes. The model had a Receiver Operating Characteristic …

Driscoll’S Water-Use Efficiency (Wue) Strawberry Breeding Trial, Aidan Inoue

Plant Sciences

California’s water supply is seeing stress and growers are increasingly under pressure to lower their water use. While reducing irrigation to strawberry plants can be used to raise sugars (°bx), research on the impact of deficit irrigation on plant growth, fruit yield and quality are not yet quantified. The purpose of this experiment is to observe the effects of a ~50% deficit irrigation treatment on tabletop strawberry plants where drainage measurements and plant absorption can be recorded. Results indicate that plant vigor and total marketable yield are predominantly treatment dependent whereas fruit characteristics, including culls and berry size are reliant …

Analysis And Installation Of A Demonstration Agroforestry Orchard For Californian Mediterranean Plant Communities, Brandon Hurd

Master of Science in Environmental Sciences and Management Projects

Climate-appropriate agroforestry can provide low-input food security and ecosystem services for local Californian Mediterranean climates, while conserving natural resources (e.g., water, nitrogen, etc.). This project showcases a variety of agroforestry methods for five common plant communities of California and other analogous Mediterranean climates at the CAFES Experimental Farm on the campus of Cal Poly San Luis Obispo. Plant community species and their ethnobotanical uses were analyzed to mimic and incorporate aspects of native flora. Agricultural plants were also characterized to represent each of the five selected plant communities. GIS was used to assess the project site for soil, slope, and …

Lichens Of Ultramafic Rocks: A Multidisciplinary Approach To Understanding The Ecology Of An Understudied Organism In A Well-Studied System, Michael Mulroy

Master's Theses

Lichens are among the most prominent and successful life forms of metal-rich habitats, including ultramafic rocks and soils; however, research on lichens of ultramafic habitats is limited, especially on the North American continent. A review of the published literature on lichens of ultramafic substrates in North America yielded a total of 437 lichen species reported from ultramafic rocks and soils. Lichen assemblages of ultramafic substrates vary in composition and are dominated by acidophytic (low pH preferring) taxa with a minor, but consistent, basiphytic (high pH preferring) component. Species lists from ultramafic habitats in different geographic regions varied widely, suggesting that …

Determination Of Fungicide Resistance In Botrytis Cinerea On Wine Grapes In California's Central Coast Region, Evelyn Alvarez-Mendoza

Master's Theses

Botrytis bunch rot, caused by Botrytis cinerea, is a fungal disease that primarily affects the fruit of wine grapes. Infection of fruit consequently results in reduced yields and wine quality. These factors lead to significant economic losses for growers which prompts the implementation of management practices to control the disease. One objective of this study was to evaluate the level of resistance that populations of B. cinerea in the Central Coast region showed to various chemicals. A fungicide assay was conducted to determine resistant phenotypes to six fungicide active ingredients (pyrimethanil, iprodione, fenhexamid, fludioxonil, trifloxystrobin, boscalid). Thirty-five (2020) and …

Developing A Miniature Smart Boat For Marine Research, Michael Isaac Eirinberg

Computer Engineering

This project examines the development of a smart boat which could serve as a possible marine research apparatus. The smart boat consists of a miniature vessel containing a low-cost microcontroller to live stream a camera feed, GPS telemetry, and compass data through its own WiFi access point. The smart boat also has the potential for autonomous navigation. My project captivated the interest of several members of California Polytechnic State University, San Luis Obispo’s (Cal Poly SLO) Marine Science Department faculty, who proposed a variety of fascinating and valuable smart boat applications.

Seed Longevity And Climatic Tolerance Of San Joaquin Wooly-Threads (Monolopia Congdonii; Asteraceae) An Endangered Plant From The San Joaquin Desert, California, Paul Excoffier

Master's Theses

San Joaquin wooly-threads (Monolopia congdonii; Asteraceae) is a federally-listed, endangered annual plant species from the desert areas of the San Joaquin Valley. Its limited range puts it at risk of extinction if the climate changes in such a way as to hinder its growth and reproduction. The primary aims of the study were to 1) determine how long-lived the seeds of the M. congdonii are, a key determinant of survival of desert annual plant populations through long droughts and 2) determine how severely hotter, drier conditions impact the ability of emerged plants to grow and reproduce. Secondarily, I …

Effects Of Nitrogen Management And Cultivar On Strawberry Production Under Disease Pressure, Kamille A. Garcia-Brucher

Master's Theses

Effects of nitrogen management and cultivar on strawberry production under disease pressure

Kamille Garcia-Brucher

California strawberry growers face increasing regulatory pressures to manage nitrogen (N) applications in their production system. Standard practice in the California strawberry industry is to apply a synthetic pre-plant controlled release fertilizer (CRF) to ensure the crop has sufficient N during winter establishment. Some research from the UC Cooperative Extension suggests this practice is not efficient at delivering N to the crop since most of the N is released from CRF before strawberry crop N uptake is significant. Another concern for California strawberry growers is loss …

Climate Adaptation And Water Conservation Decision-Making In Paso Robles, California Vineyards, Christopher R. Klier

Master's Theses

This paper examines vineyard perceptions and adoption of climate change adaptation and water conservation measures in the Paso Robles American Viticultural Area (AVA). A survey was distributed to all 220 vineyards and vineyard management companies that operate in the AVA, with a 53.64% response rate. The objective of the survey was to determine vineyard manager and owner attitudes towards climate change and adaptation, as well as their perceptions of how these threats would impact their operation. A second objective was to document the current level of water conservation and climate adaptation while identifying the barriers and opportunities for further adoption …

Effects Of Compost On Soil Health And Greenhouse Gas Emissions: A Case Study In A Mediterranean Vineyard, Tsz Fai Wong

Master's Theses

Compost is commonly used as an organic amendment in cropping systems such as vineyards, and has been shown to be beneficial to carbon (C) sequestration and soil health. As perennial crops, grapevines have a larger potential for C sequestration than most crops. Yet, there is a lack of understanding regarding the relationship between compost application rate, the magnitude of C sequestration, and its environmental tradeoff in the form of greenhouse gas (GHG) emissions. In the study, we investigated the effects of compost application rate on soil C sequestration, GHG emissions, crop growth, and overall soil health after two annual compost …

Evaluation Of Masculinization Treatments To Produce Feminized Hemp Seed (Cannabis Sativa L.), Ted Fitzgerald, J. Wyatt Brown

Master's Theses

Cannabis sativa L. (hemp) develops plants with either male or female flowers, and growers of hemp greatly prefer female flowers which bear the glandular trichomes that contain cannabinoids. Feminized (all female) seeds are highly desired, which are produced by crossing a female plant with a masculinized female plant. Masculinization is achieved through the inhibition of ethylene and/or addition of gibberellins before flower initiation in female plants. The hemp industry uses silver thiosulfate (STS) to masculinize hemp, but spraying silver poses environmental concerns. This study compared STS to three other ethylene-inhibiting agents: aminoethoxyvinylglycine (AVG), cobalt nitrate (CBN), and 1-methylcyclopropene (1-MCP). Treatments …

Reciprocal Transplant And Machine Learning Study Of Oak Mistletoe On Three Host Oak Species In Santa Margarita, California, Ella Abelli-Amen

Master's Theses

At Santa Margarita Ranch, California, oak mistletoe (Phoradendron villosum) parasitizes valley oak and blue oak but cannot be found growing on coast live oak despite its abundance and ability to parasitize coast live oak in other areas. It seems as though this species of mistletoe is specializing on certain host oak trees, but the mechanisms of this specialization are unknown. In order to investigate this pattern, we utilized a type of machine learning in GIS called supervised classification as well as a reciprocal transplant study in the field. The three species of oak trees were classified with 87% accuracy using …

The Future Of Organic Insect Pest Management: Be A Better Entomologist Or Pay For Someone Who Is, David H. Headrick

Horticulture and Crop Science

Insect pest management in certified organic production systems presents considerable challenges for growers. The Federal National Organic Program (NOP) guidelines list acceptable tactics, but their effective use requires a considerable knowledgebase in entomology. The range of tactics allowed by the NOP are viewed as limiting by many growers and there are important elements missing from the list such as pest monitoring and identification. Educational programs must consider utilizing instructional methods and additional means of outreach that introduce new pest management tactics that are individualized, regionally appropriate and emphasize grower adoption and collaboration with local professionals. This review describes the challenges …

Estimating Food Waste Due To Food Safety Recalls And Investigating Ways To Minimize Negative Impacts, Mykayla Latronica

Master's Theses

For years the issue of food waste has been recognized and quantified; however, food safety issues often go unrecognized as a source of food waste. One objective of this research is to estimate quantities and monetary value of fruits and vegetables implicated in food safety recalls, and thus wasted. Using publicly available data we identified all recalls involving vegetable or fruit commodities contaminated with Listeria monocytogenes, pathogenic E. coli, or Salmonella during 2015-2018. When quantities were provided, monetary value of recalled product was calculated using USDA ERS 2016 average retail prices. Although data limitations only allowed analysis of …

Strawberry Powdery Mildew Caused By Podosphaera Aphanis: Fungicide Resistance And Host Plant Resistance, Michael G. Palmer

Master's Theses

Strawberry powdery mildew, caused by Podosphaera aphanis, affects leaves, fruit, and runners of strawberry plants. Infected leaves have reduced photosynthetic capability and infected fruit become unmarketable. Both of these factors translate to economic loss for the grower and therefore merit taking measures to control the disease. One objective of this study was to evaluate the resistance developed in populations of strawberry powdery mildew to chemical control measures. A fungicide assay was developed to evaluate the efficacy of six treatments (penthiopyrad, quinoxyfen, myclobutanil, trifloxystrobin, cyflufenamid, fluopyram + trifloxystrobin) for control of the disease. Nineteen isolates of strawberry powdery mildew were …

Sensory Stressors Impact Species Responses Across Local And Continental Scales, Ashley A. Wilson

Master's Theses

Pervasive growth in industrialization and advances in technology now exposes much of the world to anthropogenic night light and noise (ANLN), which pose a global environmental challenge in terrestrial environments. An estimated one-tenth of the planet’s land area experiences artificial light at night — and that rises to 23% if skyglow is included. Moreover, anthropogenic noise is associated with urban development and transportation networks, as the ecological impact of roads alone is estimated to affect one-fifth of the total land cover of the United States and is increasing in space and intensity. Existing research involving impacts of light or noise …

Increasing Groundwater Recharge Activity In The San Joaquin Valley Of California, Jacob Willhite, Jacob Willhite

Agricultural Education and Communication

Over the past several decades, groundwater has become a primary source of water used for agriculture in California. Surface water available for agricultural use has depleted due to declining rain totals and reallocation to environmental purposes. As a result, groundwater overdraft has become a severe challenge, especially in the San Joaquin Valley of California. This excessive overdraft causes a plethora of issues, one of the most serious being land subsidence (Faunt, Sneed, Traum, & Brandt, 2016). Studies suggest some areas of the San Joaquin Valley have experienced more than a 28-foot drop in the land level since the 1970’s (Alley …

Public Relations Of Cal Poly Avocado Rootstock Trial, Angel Daniel Carrillo

Agricultural Education and Communication

Avocados have been one of California’s specialty crops for quite some time now. The industry has been motivating growers to implement the best management practices to ensure stable and increased production as much as they possibly can. California is the leading state in the country for avocado production. In 2019, California alone produced 109 tons of avocados (US Department of Agriculture, 2020). Unfortunately, root rot has made it a challenge to do so.

Root rot is a disease derived from the Phytophthora cinnamomi pathogen. This is an issue for avocado production worldwide. In efforts to find a method of decreasing …

Attractiveness Of English Thyme (Thymus Vulgaris L.) To Arthropod Natural Enemies And Its Suitability As A Dual Use Resource, Kristina K. Van Wert

Master's Theses

Current agroecosystem management practices have a negative effect on natural enemies and their ability to control insect pests. Conservation biological control through the addition of flowering resources can manage food resources for natural enemies. These floral resources can also provide multiple ecosystem services. Study goals were to determine if perennial Thymus vulgaris L. was attractive to natural enemies and if so, could it be a dual use resource encouraging pest management and providing harvestable product. In 2018 plots in three locations were used to examine the effect of habitat throughout the growing season on the attractiveness of T. vulgaris. …

Valorization Of Carrot Processing Waste, Alexandra M. Duval

Master's Theses

Commercial carrot processors produce up to 175,000 tons of carrot waste annually. Carrot Mash (CM) is the term referring to the waste by-product of peeled baby carrot processing. Transportation of carrot processing waste is expensive due to its high- water content (approx. 83-95%). High in bioactive compounds (carotenoids) and dietary fibers, it is expected that its conversion into a value-added by-product is of interest to the carrot processing industry. Hemicellulose-rich plant materials have proven to be a source of oligosaccharides, which are known for their beneficial prebiotic activity. The objectives of this research were to: 1) determine the effect of …

Do Elevation And Aspect Predict Functional Trait Values In Alpine Plant Populations?, Karen Analiesa Bach

Biological Sciences

Alpine regions are among the hardest hit by global climate change, experiencing rising temperatures at a faster rate than lowland areas. Such fast rates of warming are predicted to cause rapid changes in alpine plant communities, including shifts in plant functional traits along elevation gradients. To investigate these effects within species, we examined the relationship between elevation, aspect, and functional traits of three common alpine plants in California; the shrub Holodiscus discolor var. microphyllus, the forb Calyptridium umbellatum, and the grass Trisetum spicatum. Functional traits examined included plant height, plant width, and Specific Leaf Area (SLA). These …

Evaluation Of Pheromone Mating Disruption For California Red Scale Control In Commercial California Citrus, Joel Timothy Leonard

Master's Theses

California red scale (CRS), Aonidella aurantii, is an increasingly injurious insect pest for the California citrus industry due to insecticide resistance, changing weather patterns, and shifting trade regulations. The presence of the insect on fruit, damages the rind of the fruit and high populations can cause dieback of branches as well as lower yields. Pheromone mating disruption of CRS has the potential to alleviate population control concerns and reduce insecticide use. The efficacy of the pheromone mating disruption technique for pest management of CRS was determined using the products CheckMate® CRS and Semios CRS Plus. CheckMate® CRS was evaluated …

Santa Rosa Island Restoration Study: Fog Fences Vs. No Fences, Aimee Newell, Stephen Bednar, Kathryn Mceachern

STAR Program Research Presentations

Santa Rosa Island, Channel Islands National Park, was grazed by cattle, sheep, pigs, elk, and deer for 154 years, degrading the island’s vegetation and causing erosion. In 1998, the livestock were removed, and in 2011 the remaining big game animals were removed, allowing ecosystem recovery to begin. This study evaluated growth of two native species planted in 2016, at the cloud forest restoration site on the Soledad Ridge. Baccharis pilularis (coyote brush) was planted as nursery stock from 2-inch pots, while Quercus pacifica (island scrub oak) was planted as sprouted acorns. The plants were watered with drip irrigation 2016-2018, …

Effects Of Sudangrass Cover Crop And Soil Solarization On Weed And Pathogen Management In Organic Strawberry Production, Timothy Jacobs

Master's Theses

Field and lab experiments were conducted to determine the efficacy of sudangrass (Sorghum X drumondii (Nees ex Steud.) Millsp. & Chase) cover crop management techniques and soil solarization on important agricultural weeds and pathogens in organic strawberry production in Central California. Lab experiments assessed the time needed to kill weed seeds at temperatures typically achieved during soil solarization (40°C, 45°C, 50°C, 55°C, and 60°C) in California. Seeds tested included little mallow, redstem filaree, bristly oxtongue, annual sowthistle, common purslane, nettleleaf goosefoot, and redroot pigweed. Efficacy of simulated …

Leaf Functional Traits As Predictors Of Drought Tolerance In Urban Trees, Sophia Huang

Master's Theses

The services that urban trees provide to human society and the natural environment are widely recognized, but urban trees are in jeopardy due to climate change and urban stressors. With drought as a major threat in many areas, it is important for the future of urban forestry to select species composition based upon performance under water stress. Certain leaf functional traits can help horticulturalists more accurately predict water usage of urban trees. Comprehension through rigorous experimentation is lacking, partly due to the thousands of mostly exotic species. Previous studies suggest that species whose leaves have a denser arrangement of smaller …

Evaluation Of Host Resistance And The Utilization Of Organic Amendments To Manage Macrophomina Crown Rot Of Strawberry In California, Jonathan W. Winslow

Master's Theses

The production of strawberries can be severely limited by soilborne plant pathogens, insects and weeds. Macrophomina phaseolina is a problematic soilborne fungal pathogen in California strawberry production inciting the disease Macrophomina crown rot. When established, the pathogen can cause extensive plant decline and mortality. Host resistance will be a critical tool for managing this disease and guiding breeding programs in the post methyl bromide era. Evaluation of host resistance in strawberry germplasm to M. phaseolina was evaluated through phenotypic assessments of disease incidence. A total of 90 strawberry cultivars and elite selections were included in a replicated field trial conducted …

The Effects Of Agricultural Waste-Based Compost Amendments In Organic Pest Management, Gregg T. Stephenson

Master's Theses

Soil-borne pests and pathogens, such as Verticillium dahliae, can devastate a wide range of annual and perennial crops. Current management options for organic production are limited and sustainable management of pathogens, weeds, and arthropods is important for staying profitable and reducing the use of harmful chemicals. Organic soil amendments play an important role in supplying some of the nutritional needs of vegetable crops and improving soil structure, while also contributing to pest control. The objective of this research was to determine the effects of grape and olive-based composts on soil pathogen load, arthropod communities, and weed biomass and diversity. …

Modifying Succession: A History Of Vegetation Alliances On Swanton Pacific Ranch, Jill Wilson O'Connor

Master's Theses

This thesis conducts historical research into Swanton Pacific Ranch in the County of Santa Cruz, an interdisciplinary facility for education and research managed by Cal Poly’s College of Agriculture, Food and Environmental Sciences. The study seeks to determine whether there have been discernable changes in vegetation alliances (communities), spatially or in type, within a 110-acre Study Area from the early twentieth century to the present day and how the changes compare with other similar historical analyses in California. Historical farming and ranching uses of the area are researched, and two family case studies are presented as paradigms of potential changes …

An Albino Mutant In Brassica Rapa Maps To The Pdx2 Locus On Chromosome 10, Beatriz M. Garcia

STAR Program Research Presentations

We have identified an albino mutant in the plant Brassica rapa. This recessive mutation could provide insights into the photosynthetic pathways of all plants. Previously the mutation was mapped to chromosome 10 of Brassica rapa. To narrow down the chromosomal region containing the albino mutation, we grew a segregating population of plants. DNA was extracted from albino and wildtype (green) plants and genotyped using PCR markers on chromosome 10. The genotype detected using the INDEL2 marker perfectly predicted whether a plant was albino or WT. This indicates that the INDEL2 marker is tightly linked to the albino mutation. INDEL2 is …

An Albino Mutant In Brassica Rapa Maps To The Pdx2 Locus On Chromosome 10, Cezar L. Sanchez, Beatriz M. Garcia, Edward Himelblau, Nick Diaz

STAR Program Research Presentations

We have identified an albino mutant in the plant Brassica rapa. This recessive mutation could provide insights into the photosynthetic pathways of all plants. Previously the mutation was mapped to chromosome 10 of Brassica rapa. To narrow down the chromosomal region containing the albino mutation, we grew a segregating population of plants. DNA was extracted from albino and wildtype (green) plants and genotyped using PCR markers on chromosome 10. The genotype detected using the INDEL2 marker perfectly predicted whether a plant was albino or WT. This indicates that the INDEL2 marker is tightly linked to the albino mutation. INDEL2 is …