Horticulture Commons^™

Evaluation Of Ultraviolet-C Light For Control Of Mites And Western Tarnished Plant Bug In Strawberry & Interactive Lethal Effects Of Common Strawberry Fungicides And Adjuvants On Phytoseiulus Persimilis, Colin T. Koubek

Master's Theses

California strawberry production relies heavily on chemical pesticides to manage arthropod pests and diseases, but pesticide resistance, regulatory pressure, and the need to conserve biological control agents have increased interest in alternative pest management tools. This thesis evaluated ultraviolet-C (UV-C) light as a nonchemical management tool for key strawberry arthropod pests and assessed the compatibility of common strawberry fungicides and adjuvants with the predatory mite Phytoseiulus persimilis Athias-Henriot. The first objective was to determine the ovicidal and lethal effects of UV-C light on Lygus hesperus Knight eggs and nymphs. Laboratory and field ovicide assays were conducted using UV-C doses relevant …

Improved Management Strategies For Botrytis Fruit Rot, Macrophomina Root Rot, And Verticillium Wilt In California Strawberry Production, Joseph A. Ramirez

Master's Theses

Strawberry production in California is limited by plant diseases such as Macrophomina root rot (MRR) caused by Macrophomina phaseolina, Verticillium wilt (VW) caused by Verticillium dahliae, and Botrytis fruit rot (BFR) caused by Botrytis cinerea. Current disease management strategies are compromised due to fumigant regulations or ineffective disease management practices. This thesis investigated methods to potentially improve the management of these three diseases. Two host plant resistance evaluations for MRR and VW were conducted for the 2022-2023 and 2023-2024 growing seasons. Sixty-three strawberry genotypes were screened in both years. All plants were exposed to the pathogen via artificial …

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 …

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 …

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 …

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 …

Effect Of Evapotranspiration Rate On Almond Yield In California, Dafne Isaac Serrano

Master's Theses

Since 2011, California has been under drought conditions. These conditions have not only affected water availability for farmers, but also production. California’s second most valuable crop, almonds, has been affected by drought conditions. This study used three models (Model 1-3) to describe almond yield variability from year to year and almond yield variability within a year in Kern County, CA. The study evaluated 185 almond farms that were classified in three locations (east side, west side and north west side). The years of the study were 2011 (wet year) and 2013-2015 (drought condition years). Model 1 determined a functional regression …

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 …

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 …

Araucaria In The Urban Landscape: A Novel Leaning Pattern And Evidence Of Cultivated Hybridization, Jason W. Johns

Master's Theses

Our understanding of the natural world is constantly evolving and strengthening as more observations are made and experiments are performed. For example, we understand that tree stems grow toward the light (positive phototropism; Darwin 1880, Loehle 1986, Christie et al. 2013) and against gravity (negative gravitropism; Knight 1806, Hashiguchi et al. 2013). We also know that plants respond to mechanical stimulus and perturbation (thigmotropism; Braam 2005). Genes and their resulting proteins have been described to uncover some of the mechanisms for these environmental responses, but relatively speaking, we have just scratched the surface (Wyatt et al. 2013). While the discovery …

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 …}

Determining Colonization Efficacy Of Commercial Mycorrhizae Products And Fragaria X Anannassa ‘Albion’., Tommy Jue, Alexandra Wollenman

Horticulture and Crop Science

No abstract provided.

The Effects Of Slow-Release Aluminum Sulfate On Bloom Color Of Hydrangea Macrophylla, Patrick James Edziak

Horticulture and Crop Science

Hydrangea macrophylla is a common greenhouse crop typically produced for the late winter and spring holidays. Most varieties are capable of producing either pink or blue flowers depending on aluminum content and pH of the growing medium. The goal of this experiment was to examine the effects of new controlled-release aluminum sulfate products on bloom color. This new product was applied as a topdress and a pre-plant incorporated mix using two different manufacturer recommended rates. Results were directly compared with those produced using a traditional water-soluble aluminum sulfate drench application. Controlled release aluminum sulfate was found to be at least …

Pacific Plug & Liner Crop Shrinkage Evaluation, Jillian Balli

Horticulture and Crop Science

Crop Shrinkage has a major impact on a company’s bottom line. There are many ways to combat shrinkage. This report focuses on shrinkage reduction by adjusting buffer planting numbers to reflect the actual number of plants lost in production. Inaccurate buffer can cause the cost of production to be inaccurate as well. This report evaluates crop shrinkage of a greenhouse located in Watsonville, CA called Pacific Plug & Liner.

Studies To Characterize Heavy Metal Content And Migration From Recycled Polyethyleneterephthalate, Michael John-Ross Whitt

Master's Theses

Packaging Materials account for 31% of the world’s municipal solid waste. Agencies like the Environmental Protection Agency (EPA) and the Agency for Toxic Substances and Disease Registry (ATSDR) are pushing for the increased use of recycled thermoplastic materials. Polyethylene terephthalate (PET) is a commonly recycled thermoplastic which is used to package ready-to-eat fruits and vegetables. Most recycled polyethylene terephthalate (RPET) packaging materials contain heavy metal catalysts, the most common being antimony. The recent increased use of recycled plastic materials has been suspected as the source of increased human heavy metal exposure. In this study, cadmium, chromium, nickel, lead and antimony …

Cultural And Environmental Factors Affecting The Production Of Dendranthema X Grandiflorum, Mary Rebecca Lacy

Horticulture and Crop Science

The purpose of this experiment was to reduce the schedule of cut mum production by decreasing the number weeks of long days and supplementing the flowers with the plant hormone gibberellic acid (GA). GA is a plant hormone which enlarges the cells of the stems and could conceivably affect mum vegetative growth during long days. In this experiment, long days were reduced to 0, 3, 10, 13, 17 and 20. During the long day treatments, different rates of products were applied. Both ProGibb 4% and Fascination were used to look at the effects of the different variations of GA; GA …

A Feasibility Study On Possible Uses For A Common Area Greenbelt In A Southern California Neighborhood, Sarah J. Doherty

Horticulture and Crop Science

Common greenbelt areas within residential neighborhoods are capable of existing as multi-function zones. ‘The Village’ in Southern Orange County, California, envisions its greenbelts as benefiting the homeowners, both in cost and esthetics, all beneficial insect and plant species, and the surrounding micro-climate. Research was conducted on three different systems, aimed at improving the areas of ‘The Village’ both economically and environmentally; the areas of focus were vineyard installation, fire resistant landscaping, and low impact development installations. The process began with evaluating the sites physical and judicial restraints. Soils tests, topography calculations, climate records, and preexisting species identifications were conducted; documents …

The History Of Trial Gardens, Hallie Schmidt

Horticulture and Crop Science

Essay explores the history of home gardening and seed industry in America and the conditions that led to the development of the All-America Selections.

Creation Of A Pamphlet On Young Tree Care, John G. Sanchez

Horticulture and Crop Science

No abstract provided.

Survey Of Suitable Plants For Cal Poly's Green Wall, Katrina Burritt

Horticulture and Crop Science

Green wall technology is a growing industry in the United States and has been very successful for a several years throughout Europe. The objective of this survey was to study the success of several different species of plants on a vertical wall facing south at Cal Poly’s Horticultural Department Unit. At first the focus was aimed at using California native species, because it was thought that natives would be better acclimated to the exposure in this specific location. It became apparent that plants should not be selected for the wall based just on the fact that they are California natives. …

Landscape Design, Cost Estimate, And Management Plan, Garrett Talbot Williams

Horticulture and Crop Science

The purpose of this project is to evolve a bleak landscape into something that the home owner can appreciate and love. This project will demonstrate the knowledge of this process to provide as a guide for others. This project gives an overview of all aspects of a landscape project including: drawings of an irrigation layout, planting plan, drainage plan, and a construction plan. This project takes place in Riverbank, California, which is located in the Central Valley. The property’s main centerpiece is a pool and adjacent waterfall. However, the landscape currently surrounding the pool is very bare and lacks aesthetic …

High School Horticulture Curriculum, Margaret Maratsos

Horticulture and Crop Science

Horticulture is just one of the many topics covered in a high school agriculture curriculum, and yet, there are very few lesson plans or resources available to teachers for these classes specifically. The objectives of this project were to compile a set of lesson plans, lab plans, and tests that would emphasize interactive and investigative learning. The lesson plans were written in such a way that they reflected a certain set of standards, set down by the state of California, and were meant to serve as a bare outline of topics that would be discussed within a week’s worth of …

Response Of Evergreen Perennial Tree Crops To Gibberellic Acid Is Crop Load-Dependent: Ii. Ga3 Increases Yield And Fruit Size Of ‘Hass’ Avocado Only In The On-Crop Year Of An Alternate Bearing Orchard, Lauren C. Garner, Grant Klein, Yusheng Zheng, Toan Khuong, Carol J. Lovatt

Horticulture and Crop Science

Despite problems of low fruit set, small fruit size and alternate bearing, the Hass cultivar dominates commercial avocado production worldwide. To increase yield and fruit size, gibberellic acid (GA₃) (25 mg L⁻¹) was applied at different stages of ‘Hass’ avocado tree phenology: (i) mid–late April (flower abscission), end of June–beginning of July (fruit abscission and beginning of the exponential phase of fruit growth), and mid-January (beginning of pre-harvest fruit drop); (ii) end of June–beginning of July; and (iii) mid-September (near the end of the major fruit abscission period; period of …

Temperature Thresholds And Degree-Day Model For Marmara Gulosa (Lepidoptera: Gracillariidae), M. J. O'Neal, David H. Headrick, Gregory H. Montez, E.E. Grafton-Cardwell

Horticulture and Crop Science

The developmental thresholds for Marmara gulosa Guillen & Davis (Lepidoptera: Gracillariidae) were investigated in the laboratory by using 17, 21, 25, 29, and 33°C. The lowest mortality occurred in cohorts exposed to 25 and 29°C. Other temperatures caused >10% mortality primarily in egg and Þrst and second instar sap-feeding larvae. Linear regression analysis approximated the lower developmental threshold at 12.2°C. High mortality and slow developmental rate at 33°C indicate the upper developmental threshold is near this temperature. The degree-day (DD) model indicated that a generation requires an accumulation of 322 DD for development from egg to adult emergence. Average daily …

Digital Mapping As A Student And Staff Communication Tool, Ryan Gyurkovitz

Horticulture and Crop Science

A study in the use of Geographic Information Systems in the development of digital maps for use by students and staff in Plant Identification Courses.

Savvy About Succulents, Mardel Runnels, Jessica Paulisich

Agricultural Education and Communication

The purpose of this project was to create an educational booklet explaining that succulents make fantastic SAE projects. The booklet was designed to be helpful to both high school students and high school instructors. All students enrolled in agriculture programs have projects known as SAE’s. This booklet includes a variety of topics that are relevant to having an SAE project. All information was based on industry statistics and information gained from courses. The booklet can be distributed both electronically and in a print version. The major consideration in the design of this project was to develop a booklet that would …

Meeting Learning Objectives Through Service-Learning: A Pomology Case Study, Lauren C. Garner

Horticulture and Crop Science

Undergraduate students enrolled in the introductory pomology course at California Polytechnic State University, San Luis Obispo, CA, from 2007 to 2010, participated in a service-learning project. Students helped the community organization, the California Rare Fruit Growers (CRFG), teach grafting skills to San Louis Obispo County high school students and community members. At the end of each quarter, pomology students completed evaluations of their experience. Results of these evaluations were used to improve teaching methodology and the experience in which the students participated. Self-reported and instructor evaluations of the service-learning project demonstrated that students increased their grafting knowledge and skills, their …

A Comparative Study Of Three Growing Media And Four Plant Groups Under Extensive Green Roof Conditions In San Luis Obispo, Ca, Todd Alan Nelson

Master's Theses

ABSTRACT A Comparative Study of Three Growing Media and Four Plant Groups Under Extensive Green Roof Conditions in San Luis Obispo, California Todd A. Nelson Green roof growing media and plant species are critical factors when deciding on the best materials for a project. Growing media must be chosen in accordance with load bearing capacities of structures and water requirements of the plant material. Plant species must be able to thrive in the climate of the green roof and withstand a green roof’s harsh environment. The objectives of this research were: (1) to determine which of three extensive green roof …