Life Sciences Commons^™

Deconstructing The Art Of Physical Weed Control, Jordan W. Parks

Electronic Theses and Dissertations

Farmers adjust physical weed control (PWC) tools to optimize efficacy based on observations of weeds, the crop, and soil conditions. These many variables make PWC research challenging. To study PWC tool settings more closely, we constructed a soil bin with a mobile tool carriage inside of a heated glasshouse. The soil bin was 2 m wide by 12 m long by 1 m high, with a tool carriage that can operate at 0.4 to 19.0 km h^-1. Tool angle, spacing, depth, and speed can all be precisely adjusted from the tool carriage and control panel. The goal of …

Influence Of Biochar As A Soil Amendment On Soil Water Content And Wild Blueberry Physiology, Abigayl Novak

Electronic Theses and Dissertations

Maine wild (or lowbush) blueberries (Vaccinium angustifolium Ait.) continue to face challenges imposed by climate change. Reduced frequency of precipitation and increased drought conditions have negatively impacted this crop since it resides in sandy soils with limited retention of water and nutrients. The wild blueberry plants growing in water- and nutrient-poor sandy soils are likely to have poor resilience to drought, resulting in a decline in berry yield during drought years. Thus, there is an urgent need to find a drought management solution for wild blueberries. Compared with other drought management practices, such as irrigation systems, mulching, and adopting drought-resistant …

Effects Of Lobster Shell Meal As A Soil Amendment On Verticillium Wilt And Potato Growth, Ross Sousa

Honors College

Potatoes (Solanum tuberosum L.) are the most valuable crop in the state of Maine. Despite the crop’s success in the state, potato growers still face the challenges of various abiotic and biotic stresses, including diseases such as potato early dying, caused by the soilborne fungal pathogen, Verticillium dahliae. The disease has been controlled by soil fumigation and fungicides. As an alternative method, organic byproducts, such as lobster shell meal (LSM) or compost, can be used. The benefit of using LSM is thought to occur through the promotion of beneficial chitinolytic soil microbes which can degrade LSM. The derivatives …

Determining Effects Of Management Practices On Potato Early Dying And Soil Microbiome And Assessing Risk Of Fungicide Resistance In Verticillium Dahliae, Kedi Li

Electronic Theses and Dissertations

Potato early dying (PED) is a yield-constraining soilborne disease of potato, caused by Verticillium spp. with V. dahliae being the predominant causal agent. Since the pathogen inhabits soil for long periods, PED management aims to reduce the population of V. dahliae in soil. Benzovindiflupyr and azoxystrobin are effective chemicals and frequently used in the control of V. dahliae. In this study, field trials were conducted at Aroostook Farm, Presque Isle, ME in 2019 and 2020. Chemical and biological products have been studied for PED control, and fungicide resistance was also examined. To evaluate fungicide resistance, benzovindiflupyr was characterized on …

Characterization Of Dickeya Dianthicola And Pectobacterium Parmentieri Causing Blackleg And Soft Rot On Potato, Tongling Ge

Electronic Theses and Dissertations

Potato blackleg and soft rot (PBSR), which can be caused by Dickeya spp. and Pectobacterium spp., is a serious problem worldwide. The recent outbreak of PBSR in the Northeastern USA, caused primarily by D. dianthicola, has resulted in significant economic losses since 2015. This seedborne disease is highly associated with and therefore spread by seed tuber distribution. To understand how the outbreak occurred and where the pathogen originated, a total of 1204 potato samples were collected from 11 northeastern states from 2015 to 2020. All the samples were processed for bacterial isolation and DNA extraction. Dickeya dianthicola and P. …

Evaluating The Current Weed Community In Wild Blueberry Fields And Ipm Strategies For Spreading Dogbane (Apocynum Androsaemifolium), Anthony G. Ayers

Electronic Theses and Dissertations

Lowbush blueberry (Vaccinium angustifolium) is Maine’s third largest crop (USDA 2020 a). From 2017 – 2019 the three seasons yield average was 27,200 tons were harvested from 19,500 acres for a value of $22,468,000 (USDA 2020 c). Lowbush blueberries are managed on a two-year cycle. Every other year, lowbush blueberry fields are pruned to the ground either through the use of a tractor mounted flail mower or a prescribed burn (Yarborough 2009). Pruning is a necessary part of managing lowbush blueberries as the second-year growth produces the highest yield but steadily declines in subsequent years (Drummond et al. …

Tapping The Sweet Spot: Predicting The Suitability Of A Woodlot’S Potential To Transition Into A Productive Sugarbush In Maine, Deven M. Teisl

Non-Thesis Student Work

Through conversations with Dr. Sara Velardi, a postdoctoral research associate who has been doing research on maple producers’ scale management decisions in Maine, most current owners and operators in the maple syrup industry have the common interest of expanding their current operations, but they are unsure of how to approach that problem. Due to these current issues, my research focused on creating a sugarbush assessment tool. This assessment tool consists of a set of guidelines which can be utilized by current or future producers and can be used to easily assess woodlots without having to hire a consulting forester to …

Population Structure And Reproductive Biology Of Monilinia Vaccinii-Corymbosi (Reade) Honey In Lowbush Blueberry In Maine, Katherine A. Ashley

Electronic Theses and Dissertations

Lowbush blueberry, Vaccinium angustifolium Aiton, is both an economically and culturally important crop in Maine, being one of the few endemic crops to North America. The fungus Monilinia vaccinii-corymbosi (Mvc) causes mummy berry disease and is a significant pathogen of both highbush (Vaccinium corymbosum) and lowbush blueberries. While impacts of this disease are not regularly documented, it is estimated that 30-50% of the yield in an unmanaged field can be lost because of Mvc. This disease is typically managed with fungicides or burning of the field during years when the field is pruned, however, the impacts to the …

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 …

The Dispersal Pattern Of Thekopsora Minima In Wild Blueberry Determined By A Molecular Detection Method, Nghi Nguyen

Electronic Theses and Dissertations

Blueberry rust caused by Thekopsora minima is a common disease in wild blueberry (Vaccinium angustifolium) and other Vaccinium genera. Understanding the spore dispersal pattern and disease cycle of fungal pathogens in wild blueberry is crucial for the development of a more efficient disease management program. Molecular assays for rapid detection and quantification of Thekopsora minima were developed to be incorporated with a spore trap sampling method and weather data collection to examine spore dispersal pattern and production in three different fields: Blueberry Hill Farm in Jonesboro, East Machias, and Spring Pond in Deblois, Maine, in three years 2014, …

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 …

Multi-Tactic Ecological Weed Management In A Changing Climate, Sonja K. Birthisel

Electronic Theses and Dissertations

Climate change is expected to impact weed communities in Maine, and the efficacy of tools and tactics farmers use to manage them. Through seedbank sampling and surveys of Maine organic farms, we identified currently rare weeds that are known to be especially abundant or problematic in warmer areas of the USA and might therefore represent an emerging agronomic risk. Many ecological weed management strategies that focus on depleting the weed seedbank are expected to remain effective in a changing climate, and become increasingly important as efficacy of cultivation and some herbicide applications diminish or become more variable. Through field experiments, …

Consumer Acceptance And Phytonutrient Assessment Of Cold Hardy, Locally Grown Plums, Amber L. Elwell

Electronic Theses and Dissertations

Prunus salicina, Japanese plums, and Prunus domestica, European plums, are naturally rich in fiber, minerals, vitamins and phytonutrients. Consuming plums can increase overall fruit intake and can be incorporated into part of a healthy diet. Through local plum production, harvesting can be completed without the need for cross-country shipping, which can increase overall acceptability and nutritional quality of the fruit. Furthermore, the increase in local production can help to boost Maine’s economy and creates a market for new plum product production.

The first objective of this study was to determine consumer acceptance of locally grown plum cultivars at a …

Band-Sowing With Hoeing For Weed Management In Organic Grains, Margaret R. Mccollough

Electronic Theses and Dissertations

Weeds remain the foremost production challenge for organic small grain growers in the Northeastern United States. Instead of sowing crops in narrow, single-line rows, band-sowing with inter-band hoeing is a cropping strategy that could provide superior weed control. In theory, band-sowing suppresses weeds in the intra-band zone by improving the spatial arrangement of the crop from that of typical rows to a more uniform pattern within the planted bands, maximizing interspecific and reducing intraspecific competition. Weeds in the inter-band zone are controlled by cultivating with aggressive sweeps; tine harrowing can target weeds in the intra- and inter-band zones.

Chapter one …

Optimizing Fertilizer And Compost Rates In Organic Reduced Till Agriculture, Nicholas W. Rowley

Electronic Theses and Dissertations

Interest in reduced tillage systems has been increasing and advanced by a need to practice agriculture in a sustainable way to limit environmental degradation. The focus on preserving soil integrity has become commonplace in all scales of agriculture. Recently trends in agricultural production have given rise to numerous small farms centered on local and sustainable farming. In turn, this has led to a growing desire to implement conservation tillage into these systems.

In 2015 and 2016 a collaborative effort between the University of Maine at the Maine Agricultural and Forestry Experiment Station: Highmoor Farm and Cornell University at the Homer …

Reducing Tillage In Small-Scale Permanent Bed Organic Vegetable Production Systems, Jeremiah D. Vallotton

Electronic Theses and Dissertations

The response of field-grown vegetable crops to reduced tillage and mulching in permanent beds was evaluated through measuring crop yields, weed pressure, earthworm counts, and soil basal respiration. Two vegetable crops (“Bush Delicata” squash and “Farao” cabbage) were started in April and May of 2016 and 2017 respectively, transplanted in late June, and harvested on 15-Sep-2016 and 25-Aug-2017. Fruit number and weight of squash, and head weight and feeding damage of cabbage were measured. These results suggest that intensive tillage (8” rototill every year) can be successfully reduced to alternating years of shallow (2”) rototilling and a less intensive form …

Nurse Cropping In Potato Systems, John M. Jemison Jr.

Cooperative Extension - Agriculture

In the summer of 2016, a study was conducted at the Rogers Farm in Stillwater, Maine to study the effect of short-term nurse crops on potato yield and quality. The study was designed as a randomized complete block design with six replications. The study compared two sowing rates (winter rye at 100 vs. 200 lbs/ac) to 20 lbs of annual ryegrass or a check plot (no nurse crop). In addition, each of the winter rye treatments was either killed with an herbicide prior to one-pass hilling or just hilled. To address the question of how long to grow a NC, …

Use Of Endomaxx Mycorrhizal Seed Treatment To Improve Potato Production In Maine, John M. Jemison Jr.

Cooperative Extension - Agriculture

With the increasing cost of fertilizer and the ever-decreasing supply of apatite worldwide, improving phosphorus (P) uptake should be a goal for all producers. Due to our high levels of iron and aluminum oxides in Maine soils, P efficiency is very poor. As a result, potato farmers tend to over apply P to ensure that their crop will have adequate P. Over time, this has led to increasing plant available soil test P levels. I recently requested the Maine Soil Test Lab director for potato soil tests over the past ten years. The percentage of soils testing above 40 lbs/ac …

Propagation And Container Production Of The Amelanchier Spicata Complex, Gregory J. Melcher

Electronic Theses and Dissertations

Amelanchier is a genus in the Rosaceae containing shrubs and trees indigenous to North America that possess traits valued by the horticulture industry. Amelanchier spicata (dwarf serviceberry), a heterogeneous complex of hybrids indigenous to eastern North America, has agricultural and ornamental merit with notable characteristics. White blossoms emerge in early spring, edible pomes ripen in the summer, and vibrant, orange foliage occurs in the fall. I investigated phenological and physiological factors influencing adventitious rooting of stem cuttings, the effects of nitrogen source on the development of seedlings grown in container culture, and phenotypic variation among seedlings of A. spicata from …

The Enhancement Of Wild Bees (Hymenoptera: Apoidea) For Pollination Security, Eric M. Venturini

Electronic Theses and Dissertations

The acreage of pollinator-dependent crops continues to expand across the globe. Simultaneously, honey bee hives – an annually rented commodity that growers rely on – are more expensive every year and in some cases, scarce. In response, pollinator-dependent growers seek alternative pollinators. One approach is installing bee pasture on farms, a strategy that enables systems-based farmers to become in-situ farm-scale habitat managers. This thesis first presents a review of the literature on bee pasture plantings and provides a brief overview of some methods for assessing their impacts on the pollinator community. There are three major gaps in current bee pasture …

Old Roots And New Shoots: How Locals And Back-To-The-Landers Remade Maine's Local Food Economy, Eileen Hagerman

Maine History

Back-to-the-landers who relocated to Maine in large numbers during the 1970s often lacked traditional rural skills and encountered a variety of agricultural challenges related to the state’s harsh climate and poor soils. Many who remained on the land often did so, at least initially, because they received support from elderly neighbors who still practiced low-input, small-scale farming. These neighbors tended to freely share their knowledge and skills and, in return, often benefited from the young newcomers’ assistance with laborious on-farm tasks. The newcomers worked with their local allies to form organizations, share knowledge, and coordinate marketing efforts tailored to meet …

Career: Dynamics Of Hierarchical Householdstructured Epidemiological Models, David Hiebeler

University of Maine Office of Research Administration: Grant Reports

Mathematical and computational models will be used to study populations hierarchically segregated into groups referred to as "households". These households may represent patches within an agricultural field, fields within a landscape, dorms within a school, schools within a city, cities within a region, or even subnetworks within larger computer networks. Population models and epidemiological models will be explored within this framework, complementing other work with lattice-structured populations. In the models, interactions within a household occur much more often than interactions between different households. Primary goals of the models are to better understand how and why spatially targeted and/or clustered treatments …

Production Of Minitubers From Potato Seedlings And Advanced Selections, Benildo G. De Los Reyes

University of Maine Office of Research Administration: Grant Reports

This cooperation between the University of Maine and USDA-ARS was aimed at providing the infrastructure and manpower support for the propagation and advancement of tetraploid potato breeding materials for the USDFA-ARS-Beltsville Potato Breeding Program (K. Haynes, PI).

Factors Responsible For Differences In Yield Among Lowbush Blueberry Clones, Francis A. Drummond

University of Maine Office of Research Administration: Grant Reports

Identify factors that explain differences in yield among lowbush blueberry clones. Compare high yielding clones to low yielding clones for several factors. Factors include average genetic similarity with neighbors and effects of relationship of parents in controlled crosses on fruit set, synchrony of flowering time with neighbors, freezing tolerance of closed flower buds and open flowers, floral morphological and physiological differences (nectar amounts) that might be more attractive to bees, signs of disease, etc.

Studies will focus on comparing high yielding clones to low yielding clones for several factors. Because V. angustifolium is predominantly outcrossing and self-fertility is poor due …

Application Of Spatial Modeling Tools To Predict Native Bee Abundance In Maine's Lowbush Blueberries, Shannon J. Chapin

Electronic Theses and Dissertations

Non-native honeybees historically have been used to pollinate many crops throughout the United States, however, recent population declines have revealed the need for a more sustainable pollination plan. Native bees are a natural resource that can play an important role in pollination. I used spatial modeling tools to evaluate relationships between landscape factors and native bee abundance, with a focus on the wild native bees that pollinate Maine’s lowbush blueberries. I applied the InVEST Crop Pollination ecosystem spatial modeling tool, which predicts pollinator abundance based on available floral resources and nesting habitat, to the Downeast Maine region. The InVEST model …

Potato Breeding And Variety Development For Improved Quality And Pest Resistance In The Eastern United States, Gregory Porter, Andrei Alyokhin, David Lambert, Donald Halseth, G. Yencho, John Jemison, Joshua Freeman, Keith Perry, L. Brian Perkins, Lincoln Zotarelli, Mark Clough, Mary Camire, Matthew Kleinhenz, Nicholas Dufault, Richard Veilleux, Walter De Jong, Xinshun Qu

University of Maine Office of Research Administration: Grant Reports

The eastern U.S. potato industry needs new potato varieties to overcome pest problems while reducing agricultural chemical use and to enhance marketing opportunities. This project will conduct potato breeding, germplasm enhancement, and selection studies to improve potato productivity and quality for important eastern U.S. markets. Novel and highly improved potato germplasm and varieties will be developed to reduce the impact of economically important potato pests, such as golden nematode, late blight, pink rot, and scab.

Culture Of Sargassum In Korea: Techniques And Potential For Culture In The U.S., Sarah Redmond, Jang K. Kim, Charles Yarish, Michael Pietrak, Ian Bricknell

Maine Sea Grant Publications

In an effort to develop suitable culture techniques for macroalgae in the Northeast, this guide reviews the current knowledge of Sargassum biology and reports on culture techniques learned during a research exchange between the United States (NOAA Sea Grant) and South Korea (National Fisheries Research and Development Institute).

Culture Of Sea Cucumbers In Korea: A Guide To Korean Methods And The Local Sea Cucumber In The Northeast U.S., Michael Pietrak, Jang K. Kim, Sarah Redmond, Young-Dae Kim, Charlie Yarish, Ian Bricknell

Maine Sea Grant Publications

In an effort to develop suitable culture techniques for sea cucumber (Cucumaria frondosa) in the Northeast, this guide reviews the current knowledge of C. frondosa biology and reports on techniques for the hatchery culture of the Japanese sea cucumber Apostichopus japonicus learned during a research exchange between the United States (NOAA Sea Grant) and South Korea (National Fisheries Research and Development Institute). The final portion of the guide discusses the potential adoption of the culture techniques for A. japonicus for use with C. frondosa.

Slow Food: From Farm To Healthy Body, Hannah L. Ruhl

Honors College

Slow Food is a movement devoted to the preservation and promotion of personal, environmental and community health through lifestyle changes which focus on good, clean and fair food. Good refers to food that is healthy and nutritious for the body. Food grown sustainably as in organic agriculture contains higher levels of beneficial compounds such as vitamins, minerals and phytochemicals. Clean food contains no toxic or harmful compounds that can cause detrimental effects on health. Pesticides and other chemicals are often used in food production; as a result they are found in the final product and are often detected in the …

A Characterization Of Maine Blueberry Growers In 2010, Anya Rose

Electronic Theses and Dissertations

A survey was sent to 343 lowbush blueberry growers in Maine with a response rate of 29%. Growers were asked questions about their management practices, pesticide use, priorities, decision-making influences, and beliefs about pesticide safety. Respondents categorized themselves into one of four categories: Integrated Pest Management (IPM), Conventional, Organic, and No-Spray. Analyses were conducted to examine factors that were linked to these four categories. A major goal of this study was to determine differences and similarities between growers of different management styles, and to define each category by the practices and beliefs of its members. Toxicity ratings were also calculated …