Agricultural Science Commons^™

Evaluating Fungicide Programs For Grapevine Disease Management And Fungicide Sensitivity Monitoring, Abraham Ahumada

Master's Theses

Grapevine diseases, such as powdery mildew and Botrytis bunch rot, require repeated fungicide applications to maintain fruit quality and reduce yield losses. However, fungicide performance can vary among products, application programs, disease pressure, and pathogen sensitivity. This thesis evaluated fungicide programs for control of powdery mildew in ‘Chardonnay’ grapes and assessed fungicide sensitivity of Botrytis cinerea isolates collected from California vineyards.

Powdery mildew, caused by the fungal pathogen Erysiphe necator, is a major threat to the production of Vitis vinifera grapes worldwide. Because powdery mildew management relies heavily on fungicide applications, field evaluations are needed to compare the efficacy …

Exploring Regenerative Vegetable Systems On The Central Coast Of California, Una S. O'Connell

Master's Theses

As climate change and current agricultural practices place pressure on the long term sustainability and resilience of food production systems, there is growing interest in whether existing agricultural systems can adapt to maintain productivity while improving environmental outcomes.

This study evaluated the effects of regenerative versus standard organic vegetable production systems on yield, insect communities, and weed suppression across three field trials conducted on California's Central Coast. In addition, I collected baseline soil health data for all trials. Trials 1 and 2 were carried out at the Cal Poly San Luis Obispo Organic Farm using cabbage and broccoli as cash …

Survey Of Soilborne Pathogens Infecting Strawberry In Oxnard, California & Effect Of Planting Date And Chill Treatment On Yield Of Strawberry, Samantha Z. Simard

Master's Theses

Survey to quantify the frequency of the five main pathogens (Macrophomina phaseolina, Fusarium oxysporum f. sp. fragariae races 1 and 2, Verticillium dahliae, and Phytophthora spp.) infecting strawberry in the Oxnard growing district of California. M. phaseolina was the most prevalent pathogen detected in diseased plants in the Oxnard growing district, present in 67.6% of samples positive for at least one pathogen. F. oxysporum f. sp. fragariae race 1 (35.3%), V. dahlia (8.8%), F. oxysporum f. sp. fragariae race 2 (5.9%) and Phytophthora spp. (2.9%) followed at lower prevalence. Associations were found between fewer drip irrigation lines …

Evaluating The Field Efficacy Of Uv-C On Two California Strawberry Arthropod Pests, Jose Luis Alvarado Rojas

Master's Theses

The efficacy of two different autonomous Ultraviolet-C (UV-C) units on two spotted spidermite, Tetranychus urticae Koch (Acari: Tetranychidae), and greenhouse whitefly, Trialeurodes vaporariorum. (Hemiptera: Aleyrodidae). was tested in four commercial strawberry fields in California.

In 2020, California strawberry growers used 12 million pounds of active ingredients (AIs) to keep pests under economic thresholds. While pesticides are an important part of an integrated pest management program, their use poses threats to the environment and human health. To protect agricultural workers, the public and the environment, regulators in California have consistently limited or removed the use of certain pesticide AIs. For …

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.

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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. …

Soil Science In Precision Agriculture Lesson Plan, Carson Ellis Cronkright

Agricultural Education and Communication

Due to the increasing demands for the American agricultural industry to provide exceptional products at an increasing rate of production, as well as implement the practice of sustainable farming, it is imperative that more modern concepts be taught at a younger age (Ray, 2013). In order to inform students of advancements and the future of agriculture in the United States, curriculum and lesson plans should reflect this movement in industry in order to provide relevant information and maintain the highest quality of education possible. This project will provide a constructed lesson plan as one example of adopting more progressive methods …

Converting Agricultural Lesson Plans To Be Common Core Compliant For Grades 3-5, Hattie Kaymarie Jameson, Brittany Rose Withnell

Agricultural Education and Communication

There are few Common Core approved lesson plans for teachers to incorporate into traditional science programs in California. The Farm Bureau’s Ag in the Classroom (AITC) program provides K-12 educators lesson plans with an agricultural focus. Only 13 out of 45 of the lesson plans that the California AITC website offers are Common Core approved (Learn About Ag, 2017).

Agricultural literacy is valuable to consumers, can lead to careers in agriculture, and can create a greater understanding of the world and of science for students. The agricultural lessons give students a real life relationship with what they are learning and …

Agriculture In The Classroom Farm Day Lesson Plan, Tessa Nicole Thompson

Agricultural Education and Communication

Nontraditional educational programs have been proclaimed desirable by many teachers, and proven effective through data collection and feedback (Coombs and Ahmed, 1974). Of the more popular unconventional educational programs, outside learning activities are commonly implemented as they are not only advantageous to students, but to teachers as well (Cengelci, 2013; Knoblock, 2008). Though nontraditional, much thought must be put into creating lesson plans for these educational programs.

El Dorado County’s Agriculture in the Classroom program utilizes nontraditional outdoor learning activities to conduct “Farm Day.” This lesson plan, created for Farm Day, is to teach third graders the importance of composting …

Understanding Soil Moisture Levels On Soledad Ridge, Santa Rosa Island, California During The Summer Months, Dulce M. Lopez, Stephen Bednar, Kathryn Mceachern

STAR Program Research Presentations

Santa Rosa Island located off the coast of Santa Barbara County was grazed by non-native ungulates leaving the island stripped of vegetation topsoil layer. With the removal of ungulates, the National Park Service began restoring the Cloud Forest on Soledad Ridge. Soledad Ridge is said to have once been covered by large stands of island oaks (Quercus tometella) and other endemic and native plants. The unique leaf and structural morphology of such vegetation collects water from wind derived fog which serves as the main source of water for this unique ecosystem. In an effort to jump-start ecosystem vegetation …

Hanford Ffa Ornamental Horticulture Unit Master Plan, Savanah Diane Rhine, Russell Alan Zimmerman

Agricultural Education and Communication

This project is intended to develop a more functional plan for the Ornamental Horticulture (OH) Unit at the Hanford Agriculture Program. The ag program combines all three high schools in Hanford resulting in over 1,000 students; however, a majority of these students are not in the OH Career Pathway due to a lack of a constant, fully functional unit. As a comprehensive agriculture program, it is crucial that it incorporates all aspects of agriculture, not just animal science and agricultural mechanics.

This project will provide the Hanford agriculture program with a plan to be implemented so that they may have …

Testing Predictions Used To Build An Agrivoltaics Installation On A Small-Scale Educational Model, Katie Kinney, Rebecca Minor, Greg Barron-Gafford

STAR Program Research Presentations

Models are valuable tools for explaining and testing systems. Small-scale models can be especially useful for educational purposes. For models to be useful, they have to accurately depict the larger system that they are describing. A novel man-made system, known as an agrivoltaic structure, is being constructed at Biosphere 2 near Oracle, Arizona. The word agrivoltaic is a combination of agriculture and photovoltaics, or solar farming. My research involved creating a small-scale version of this system for educational purposes. The model of this system tested two predictions: that plants will grow better in the shade of a panel and that …

Gopher Intrusion In Cropping Systems, Kenneth Romero, Paul Cardinalli

Agricultural Education and Communication

The purpose of this project was to determine if no till vs. till on gopher populations was more beneficial. Which is more efficient at controlling gophers and explain the damage they can cause and the diseases they can potentially vector. What are the different options of pest managements that have to be used when dealing with a gopher infestation in a tilled field vs. a no-tilled field.

The Effects Of Foliar Nutrient Applications On Split, Yield, And Internal Fruit Quality Of 'Wonderful' Pomegranate (Punica Granatum L.), John Matthew Chater

Master's Theses

Fruit split is the most important physiological disorder in pomegranate production, causing devastating crop losses worldwide. Foliar nutrient applications have been used experimentally to mitigate pomegranate fruit split but none have been conducted using the industry standard cultivar, Wonderful, and little is known about the effects of foliar nutrient applications on pomegranate. Additionally, investigations into putative health benefits of pomegranate fruit have increased interest in its production but limited evidence exists regarding effects of agricultural practices such as foliar fertilizer applications on internal fruit quality. ‘Wonderful’ pomegranate trees at 2 commercial orchards were treated with foliar applications of ZnSO_{4 …}

Bacterial Expression Of Plant Pyruvate Kinase, Kristina Fuller

STAR Program Research Presentations

Pyruvate kinases serve an important role in regulating glycolysis pathways. Different pyruvate kinase isozymes can dictate which of several different products will be formed during the final step of glycolysis. Being able to reliably copy active pyruvate kinases (PK) would allow study of the different isozymes, with the goal of eventually creating plants that are more nutritionally beneficial for humans. This study focused on improving the protocol for replicating each of two isolated PK isozymes from the model plant Arabidopsis thaliana. Previous attempts had resulted in the PK denaturing and consequently precipitating out of solution and so we manipulated the …

Xrf Analyses Of Prehanford Orchards, Komal Rana

STAR Program Research Presentations

Subsequent to 1943, the use of Lead Arsenic was banned from the Orchards standing on the Hanford site. This use of Lead Arsenate pesticide was popular among the orchard owners and was dispersed over the site in a myriad of ways. The presence of the traces of lead and arsenic are found today, more than half a century later. Using a portable X-ray florescence analyzer (XRF), the values of lead and arsenic are evaluated while determining the efficiency of the equipment itself. Samples from different decision sites were collected, with lead arsenic values in the low, high and medium range …

The Effect Of Increasing Rates Of Biochar On Corn Grown In Salinas Clay Loam, Joshua Fridlund

Agricultural Education and Communication

In order to sustain the ever growing global population, agriculture needs to not only increase yields but to increase yields in a way that is sustainable and is either environmentally neutral or has a positive effect on the environment. Biochar offers a solution to this challenge with numerous environmental benefits, as well as agricultural benefits (Lehman and Joseph 2009). The agricultural benefits of biochar have been well documented in tropical climates, with the benefits of biochar for other climates, such as temperate climates and Mediterranean climates, relatively unknown (Blackwell et. al. 2009). To determine the effect of biochar on agricultural …

Veggielution Community Farm Workday Leader And Farm Intern Training Manual, Sarah Wool

Agricultural Education and Communication

The purpose of this project was to write an updated and complete Workday Leader and Farm Intern training manual that could be used at Veggielution Community Farm. It could be presented as reference materials while participants are in the Workday Leader class or could be presented to Farm Interns to orient them on different jobs they might face while working on the farm. This manual provides general overview of many organic farming practices, as well as specific guidelines that Veggielution uses. It also focuses on leading volunteers to have effective workdays. It is hoped that this manual will be actively …

Updated Ethography For European Starlings (Sturnus Vulgaris) In Central Coast Vineyards, Vic A. Guerrero

Wine and Viticulture

No abstract provided.

An Index Of California Regulations Affecting Rice Growers, Maddie Dunlap

Agricultural Education and Communication

The purposed of this project was to identify and compile California regulations that affect rice growers. The final product was an index designed for rice growers and their representatives to be used lobbying efforts with regulators and elected officials. The index serves to illustrate the intensive regulations that rice growers face in California. Areas of focus include water quality, air quality, labor and pesticides indirectly.

Strawberry Growth, Yield, Fruit Nutrition, And Control Of Verticillium Wilt With Pre-Plant Soil Fumigants, Ozone, And Biological Control, Justin J. Scurich

Master's Theses

Verticillium wilt is a widespread soilborne disease of strawberry historically controlled by soil fumigation with methyl bromide (MB). MB was banned by the United Nations in 1995 and will be completely phased out by 2015. Research has concentrated on alternative methods of disease control without finding a single alternative able to replace MB in widespread disease control and yield increase. For the current study, strawberries were greenhouse grown in container pots filled with soil from both infested and non-infested areas of a commercial strawberry field in Watsonville, CA. Treatments included pre-plant soil fumigation with commercially available formulations of methyl bromide, …

Poisonous Rangeland Plants In San Luis Obispo County, Sara Litten, Amanda Ou

Animal Science

Poisonous Rangeland Plants in San Luis Obispo County is a comprehensive educational guide to rangeland plants that are toxic to domestic livestock. This guide begins with an exploration of how the biological systems are affected by the poisonous plant toxins. The biochemistry behind these toxins is included in the discussion. Next, reference material for fourteen plants that inhabit San Luis Obispo County is provided. This information includes specific toxins found in poisonous plants, affected animals, symptoms of poisoning, stages of growth, lethal dose, and distribution of the plant in California. This section of the guide is filled with helpful photos …