Physical Sciences and Mathematics Commons^™

If You've Seen One Worm, Have You Seen Them All? Spatial, Community, And Genetic Variability Of Tubificid Communities In Montana, Nilanjan Lodh, Donna M. Rizzo, Billie L. Kerans, Stephanie Mcginnis, Nikolaos Fytilis, Lori Stevens

College of Engineering and Mathematical Sciences Faculty Publications

Genetic studies are recognized increasingly as important for understanding naturally occurring disease dynamics and are used to predict host genetic diversity and coevolutionary processes and to identify species composition in ecological communities. Tubifex tubifex, the definitive host of the whirling disease parasite Myxobolus cerebralis, comprises 6 known lineages that vary widely in parasite susceptibility. We used 16S ribosomal DNA (16S rDNA) to identify relationships among genetic variability of 3 oligochaete genera (T. tubifex, Rhyacodrilus spp., and Ilyodrilus spp.; Oligochaeta:Tubificidae), oligochaete assemblage composition, and the presence of whirling disease in 9 locations across 4 watersheds in Montana, USA. We assessed genetic …

Temporal Overlap And Co-Occurrence In A Guild Of Sub-Tropical Tephritid Fruit Flies, Gleidyane N. Lopes, Miguel F. Souza-Filho, Nicholas J. Gotelli, Leandro J.U. Lemos, Wesley A.C. Godoy, Roberto A. Zucchi

College of Arts and Sciences Faculty Publications

Studies of community assembly have emphasized snapshot comparisons of spatially replicated samples from "natural" assemblages. Agro-ecosystems are characterized by relatively little habitat heterogeneity and no dispersal barriers for actively flying insects. Therefore, dynamic patterns of species segregation and aggregation are more likely to reflect the direct or indirect effects of species interactions. We studied the temporal organization of a guild of 21 congeneric species of Anastrepha that colonized fruit orchards in Monte Alegre do Sul, São Paulo, Brazil. This assemblage also included the introduced Mediterranean fruit fly Ceratitis capitata. One hundred six consecutive weekly censuses (11 Jan 2002-16 Jan 2004) …

Survey Of Northeastern Hop Arthropod Pests And Their Natural Enemies, Lilian B. Calderwood, Scott A. Lewins, Heather M. Darby

College of Agriculture and Life Sciences Faculty Publications

The commercial production of hops (Humulus lupulus L.) in the northeastern United States is on the rise due to demand from local breweries. Several arthropod pests are economically damaging to hop yield and quality. Due to climate and landscape differences between traditional and resurging hop-growing regions, there is a need for region-specific integrated pest management (IPM). We first review hop pest and natural enemy biology and management strategies. Then the phenology, abundance, and peak date of arthropod pests scouted in seven Vermont hop yards is reported. Documentation of natural enemy abundance is also reported. Our 3-yr survey indicated that hop …

Effectiveness Of Nutrient Management Plans On Vermont Dairy Farms, Heather Darby, Philip Halteman, Debra Heleba

College of Agriculture and Life Sciences Faculty Publications

A nutrient management plan (NMP) is a tool that helps livestock farmers optimize crop nutrient use. A survey of Vermont dairy farmers was conducted to learn about farmers' implementation of and perceptions about the effects of NMPs. Results showed that 46% of the 301 respondents had NMPs, particularly large and medium size operations. The majority followed the plans most of the time (barring weather and other constraints). The study revealed that NMPs affected total perceived fertilizer use and adoption of conservation practices. It showed that the person(s) updating the NMP affected the frequency to which the plan's recommendations were consulted.

Subsistence Under The Canopy: Agroecology, Livelihoods And Food Sovereignty Among Coffee Communities In Chiapas, Mexico, Margarita Fernandez

Graduate College Dissertations and Theses

One of the most pressing challenges facing the world today is how to sustainably feed a growing population while conserving the ecosystem services we depend on. Coffee landscapes are an important site for research on agrifood systems because they reflect global-scale dynamics surrounding conservation and livelihood development. Within them, we find both what is broken in our global agrifood system, as well as the grassroots struggles that strive to change the system by building socio-ecologically resilient, sustainable livelihoods. Research shows that smallholder shade coffee farmers steward high biodiversity and provide essential ecosystem services. At the same time, studies in the …

Grass-Based Dairy In Vermont: Benefits, Barriers, And Effective Public Policies, Serge William Wiltshire

Graduate College Dissertations and Theses

A comprehensive literature review was undertaken in order to define and assess the sustainability and resiliency characteristics associated with grass-based and confinement dairy farming. Primarily as a result of reduced input costs, grass-based dairy farming often enhances profitability over confinement systems, especially on small farms. Further, conversion of tilled soil to permanent pasture has been shown to significantly reduce harmful sediment and nutrient transport into waterways. Perennial forage also acts as a carbon sink, curtailing or even negating a grass-based farm's carbon footprint. Finally, social benefits derived from enhanced nutrition and higher quality of life are also associated with grass-based …

An Evaluation Of Vermicompost As A Fast-Acting Nitrogen Amendment To Mitigate Nitrogen Deficiencies In Organic Vegetable Production, Peter Dalton Austin

Graduate College Dissertations and Theses

For sustained production, organic agriculture depends on plant needs being synchronized with the release of nutrients from organic amendments during decomposition within the soil. Because decomposition is strongly dependent on soil moisture and temperature, nutrient needs may not always be met as planned or synchronous with plant need. Unlike conventional agriculture, fast acting amendments are not readily available. Much of the evidence that vermicompost benefits crop production comes from studies on seed germination and production of starts in greenhouses. Yet, there is a dearth of information derived from field studies. Soil, soil and water nitrogen, plant development, and marketable yield …

Sustainable Agriculture In Vermont: Economics Of Climate Change Best Management Practices And The Complexity Of Consumer Perceptions Of Raw Milk, Alexander Paul Helling

Graduate College Dissertations and Theses

Changing weather patterns, the declining social fabric of rural communities, and economic uncertainty increasingly pose challenges to Vermont communities. The socially and environmentally embedded production practices within sustainable agriculture present a potential solution to these problems. In order to make the most of the potential benefits of these practices society must maximize their adoption. This requires an understanding of both farmer adoption of these practices and consumer perceptions of the resulting food products. This thesis contributes two original articles on sustainable agriculture through the analysis of factors driving both farmer adoption and consumer perceptions of products and practices often thought …

Using Mutli Criteria Decision Analysis To Develop Sustainability Assessment Tools: Biomass Supply Chains, Deandra Marie Perruccio

Graduate College Dissertations and Theses

Energy access remains a significant challenge in nations lacking access to resources and strong infrastructure systems, creating barriers to economic development and to increased standards of living. Small scale biomass gasification energy (BGE) systems have been developed to meet energy needs in rural areas, creating synergies between agricultural and agro-forestry systems through utilization of biomass feedstock for energy generation. The sustainability of such systems requires sophisticated planning and coordination of the biomass supply chain.

The goal of this thesis is to investigate and improve structural and process related characteristics of sustainability assessments for small scale bio-energy systems, specifically focusing on …

Biological Indicators Of Compost-Mediated Disease Suppression Against The Soilborne Plant Pathogen Rhizoctonia Solani, Lynn Fang

Graduate College Dissertations and Theses

Compost can suppress soilborne plant pathogens that cause significant damage on globally important food crops. However, reports of plant pathogen suppression are inconsistent likely because there are no established standards for feedstock material, application rate, and maturity age upon application. Excellent results can be achieved in greenhouse trials, but field applications are much less reliable. Disease suppression occurs through the activity of biocontrol organisms (direct antagonism), and general microbial competition. Biocontrol species are hypothesized to colonize the pile during the curing phase, but single species may not be as important as microbial consortia. Substrate composition during maturation may give rise …

The Supply Chain Of Fair Trade Coffee: Challenges, Opportunities & The Future Inside A Troubled Industry, Katharine D. Lukas

Graduate College Dissertations and Theses

What started as a grassroots effort to aid tradespeople in developing nations, Fair Trade and similar certification models have, over the last sixty years, successfully established themselves as a viable alternative to conventional international trade; the ongoing growth of their market share and volume emphasize the increasing market demand for these alternatives. For coffee, Fair Trade's oldest and most established commodity, over two billion pounds was sold as certified in 2012 alone and the percentage of certified coffee continues to grow in share each year (Volcafe, 2012, Fair Trade USA 2012). As Fair Trade continues to grow, so does the …