Agriculture Commons^™

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga

Electronic Theses and Dissertations

Dickeya dianthicola (Samson) causing blackleg and soft rot was first detected in potatoes grown in Maine in 2014. Previous work has suggested that insects, particularly aphids, may be able to vector bacteria in this genus between plants, but no conclusive work has been done to confirm this theory. In order to determine whether insect-mediated transmission is likely to occur in potato fields, two model potato pests common in Maine were used: the Colorado potato beetle (Leptinotarsa decimlineata Say) and the green peach aphids (Myzus persicae Sulzer). Olfactometry and recruitment experiments evaluated if either insect discriminates between infected and …

Landscape Pattern And Wild Bee Communities In Maine, Brianne Du Clos

Electronic Theses and Dissertations

Commercial production of lowbush blueberry (Vaccinium angustifolium Aiton) in Maine relies primarily on managed honeybee hives; however, naturally occurring wild bees are more efficient pollinators of the crop. Wild bees have short foraging distances and must nest near crop fields to provide pollination services. After crop bloom, the surrounding landscape must provide sufficient forage to maintain wild bee populations for the remainder of the growing season. Lowbush blueberries in Maine are produced in a mixed-use landscape with two distinct landscape contexts. Here, we document bee communities and habitat resources (nesting and floral) in power line rights-of-way and eight land …

Contributions Of Historical Ecology To Ecological Services Assessments In The Lower Rio Grande Valley Texas, Julianna Katherine Schaefer Kurpis

Theses and Dissertations

Historic and current anthropogenic land-use activities affect ecological functions and ecosystem services quality. The clearing of native Tamaulipan thorn forest and riparian forests for agricultural use and expansion followed by rapid urbanization and population growth resulted in profound ecological impacts to the Lower Rio Grande Valley (LRGV), Texas. The goals of this study are 1) document trends in land use change and vegetation health in the LRGV 2) evaluate and demonstrate the application of the Ecosystem Services Identification & Inventory Tool (ESII Tool) for collecting ecological data and measuring percent ecological performance and 3) use historical ecology indicators to compare …

Observations And Applications Of Husbandry Methodologies On A Backyard Poultry Farm In Dangriga, Belize, Bailey Carpenter

Animal Science Undergraduate Honors Theses

This study explores the husbandry methodologies on a backyard poultry farm in Dangriga, Belize, with the purpose of producing a set of guidelines for backyard poultry growers that have limited resources in similar regions. The majority of data collection occurred through survey questions approved by the IRB, necropsies approved by IACUC, and general observations. There has been a steady increase in poultry production in developing regions due to its positive effects on income and relative nutrition. However, due to a lack of accessible communication and education regarding effective and safe poultry production, these operators typically see poor productivity and/or profitability …

The Good, The Bad, And The Ugly: Pollinators As Vectors Of Mummy Berry Disease In Highbush Blueberry, Matthew Boyer

Doctoral Dissertations

Background: Many plants must balance the need for pollination services with mediating the risk of pollinator-vectored pathogens. Vaccinium corymbosum, highbush blueberry, is negatively affected by an insect-vectored, fungal plant pathogen, Monilinia vaccinii-corymosi (MVC), the cause of mummy berry disease, in which the asexual spore mimics pollen grains and is transferred from blighted tissue to flowers via pollinators, resulting in inedible, hardened fruits. Highbush blueberry plants require outcrossed pollen for maximum yield and fecundity. Therefore, yield of blueberry plants rely on a balance between adequate pollination service and disease avoidance. Approach: To explore the relationship between pollinator community and infection …

Shizen Nōhō: Restoring The Relationship Between Food, Nature, And People In Japan, Katharine Graham

Scripps Senior Theses

In Japan’s postwar era, agriculture has become highly industrialized, involving heavy machinery, chemical fertilizers, and pesticides, all in the name of “progress.” Through employing such practices, humans have attempted to improve upon nature’s way of doing things, and in turn have degraded the soil’s fertility, natural ecosystems, and human health. In response to this, Shizen Nōhō has emerged in Japan as an alternative way of cultivating food. Shizen Nōhō practitioners challenge the notion that we need chemical fertilizers, pesticides, and machinery to farm successfully. Rather, they advocate for a way of growing food that functions seamlessly with natural ecosystems. This …

Mitigating Gaseous Nitrogen And Carbon Losses From Northeastern Agricultural Soils Via Alternative Soil Management Practices, Kyle Michael Dittmer

Graduate College Dissertations and Theses

Traditional agricultural practices often result in gaseous losses of nitrous oxide (N2O), ammonia (NH3), and carbon dioxide (CO2), representing a net loss of nutrients from agricultural soils, which negatively impacts crop yield and requires farmers to increase nutrient inputs. By adopting best management practices (BMPs; i.e., no-tillage, cover crops, sub-surface manure application, and proper manure application timing), there is great potential to reduce these losses. Because N2O and CO2 are also greenhouse gases (GHGs), climate change mitigation via BMP adoption and emissions reductions would be an important co-benefit. However, adopting a no-tillage and cover cropping system has had setbacks within …

Repelling Contarinia Nasturtii (Diptera: Cecidomyiidae), A Brassica Specialist, Using Non-Host Essential Oils, Chase Stratton

Graduate College Dissertations and Theses

Swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), is an invasive pest causing marketable losses on Brassica crops in the Northeastern United States and throughout southern Canada. Heading brassicas, like cauliflower and broccoli, are particularly susceptible because larvae feed concealed inside meristematic tissues of the plant, where head formation occurs. Our work details the development of a sustainable, affordable pest management tactic for swede midge – plant derived repellents.

First, it was necessary to establish both a damage and marketability threshold for swede midge, so we developed a technique to manipulate larval density of swede midge on cauliflower, We asked: (1) …

Quantifying White-Tailed Deer Density And Its Impacts On Agricultural Systems, Jonathan A. Matthews

Theses and Dissertations--Forestry and Natural Resources

White-tailed deer (Odocoileus virginianus) commonly consume row crops, with yield losses often attributed to their browsing. Deer density and field morphology may predict yield losses within local areas. We sought to 1) determine the effects of deer browsing on corn and soybean yields and investigate if deer density or field morphology correlated to yield loss in western Kentucky, and 2) compare pellet-based distance sampling to game camera surveys to determine if a distance sampling technique could accurately estimate deer density during the growing season. Overall, deer reduced corn and soybean yields on one-half of surveyed properties. Deer density …

Maximizing Ecosystem Services Provided To The New Oil Crop Brassica Carinata Through Landscape And Arthropod Diversity, Shane Stiles

Electronic Theses and Dissertations

Prairies, once spanning the Upper Midwest, have now largely been replaced by agriculture. The lack of resources available to pollinators in agricultural fields and the practices employed by farmers to maximize yield has led to a decline in insect and pollinator diversity. There is a need to better understand how ecosystem services provided by a diverse insect community scale to current farming practices as they relate to crop yield. We sought to explain how landscape heterogeneity relates to insect and pollinator diversity, as well as how insect diversity relates to crop yield across common farming practices. To evaluate how farming …

Diversifying Cornfields By Interseeding Cover Crops: Practical Implications And The Response Of Invertebrate Communities, Michael Bredeson

Electronic Theses and Dissertations

The lack of suitable habitat conditions for beneficial organisms in simplified agroecosystems leads to unstable invertebrate communities and overreliance on chemical control of herbivores. It is possible to manage pest populations without agrichemicals by manipulating farmland so that herbivores are impaired by plant-driven bottom-up and enemy-driven top-down antagonisms. Interseeding cover crops between established crop rows is a method used by farmers to improve habitat suitability for natural enemies and hinder host-finding, feeding and movement by herbivores. Here I address three important research gaps related to interseeding cover crops. A calcium carbonate seed coating, used to improve seed-broadcasting efficiency, was tested …

Effects Of Acute Hypoxia On Danio Rerio, Karly Crail

Williams Honors College, Honors Research Projects

The purpose of this research experiment was to determine the effects of acute hypoxia on the embryonic zebrafish (Danio rerio) cardiovascular system and assess the critical oxygen level at which embryonic function is compromised. This goal was achieved by exposing embryos to decreasing oxygen concentrations, (6.0 mg/L-0 mg/L) and observing the heart under an inverted microscope. Data analysis was conducted to determine end systolic volume, end diastolic volume, stroke volume, heart rate, and cardiac output. It was hypothesized that hypoxia would stimulate cardiac activity, because in early developmental stages, tissues are supplied with oxygen through bulk diffusion, and …

Drought And Coyotes Mediate The Relationship Between Mesopredators And Human Disturbance In California, Molly K. Parren

Cal Poly Humboldt theses and projects

Mesopredators in California are facing two major changes to their ecosystem: drought and the expansion of human disturbance. As a result, mesopredators are likely shifting their habitat use as well as their interspecies interactions to balance resource needs and risk-taking on the landscape. In response to severe drought, the California Department of Fish and Wildlife deployed 585 camera traps throughout the Mojave Desert and Central Valley documenting mammalian mesopredator presence in a drought year (2016) and a post-drought year (2017). The objectives of this study were to examine spatial patterns of mesopredator occurrence and co-occurrence with a dominant predator, the …