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PRODUCTION AND NUTRITION RECOVERY OF CROPS IN A RECIRCULATING AQUAPONIC SYSTEMSTeng Yang (7037720) 16 August 2019 (has links)
<div>The goal of this research was to improve crop yield and quality and enhance nutrient use efficiency of aquaponics for the development of sustainable aquaponic production system. Aquaponics is the integration of aquaculture and hydroponics by recirculating water and residual nutrients resulting from aquaculture wastewater into hydroponic crop production. The project had four objectives. The first objective was to characterize nutrient composition and accumulation in recirculating water and plant parts of tomato, basil, and lettuce grown in aquaponic systems, and to compare their growth and yield with those grown in hydroponic systems. The second objective was to determine the effects of feeding management regime on water quality, crop yield and quality, and N use efficiency for vegetable and herb production in recirculating aquaponics in comparison to hydroponics. The third objective was to optimize water-flow rate for efficient aquaponic system for maximum crop yield. The fourth objective was to investigate and compare the N and P mass balance between aquaponics and hydroponics. Four conclusions were determined that 1) Aquaponic solution was deficient in Ca and/or Mg leading to plant nutrient deficiency but sufficient or high in P; And luxuriant nutrient profiles in hydroponics are not necessary to enhance crop yield in aquaponics as long as key factors affecting crop yield are identified and properly addressed. 2) Uniform feeding regime improved water quality by reducing toxic ions and enhancing initial nutrient availability and considerably increased the yield, quality and nitrogen use efficiency (NUE) of crops in aquaponics as close or similar to those in hydroponics. 3) Flow rate is an important factor affecting water quality parameters and optimizing flow rate is essential to maximize aquaponic crop production and improve energy efficiency; High hydraulic loading rate at 3.3 m3/m2-day improved performance and yield of all crops in an aquaponics system regardless of their growth rate, but the water hydraulic loading rate for fast-growing and medium-growing crops can be reduced to 2.2 m3/m2-day without production reduction. 4) Plant species had significant influence on N and P removal and mass balance in aquaponics and hydroponics; Fruity vegetables showed better growth adaption in aquaponic system, while yields of leafy vegetables may be reduced when grown in aquaponics than hydroponics; Aquaponics is more efficient than hydroponics releasing less environmental wastes, however, N and P use efficiency in aquaponics and hydroponics can be further improved via proper management.</div><div>The important findings obtained from this research will fill the knowledge gap in aquaponic research and provide new management strategies to improve quantitative study of aquaponic crop production and new management strategies for cultivating crops in aquaponics. The findings will also greatly contribute to the commercial aquaponic development, and ultimately improve food security and resource use efficiency in the US and global agricultural production.</div>
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Sustainable Agri-food Production and ConsumptionJames D. Chapa (5930576) 11 June 2019 (has links)
Agri-food production is necessary to sustain the growing global population, but it adversely impacts the environment in various ways, including climate change, eutrophication, acidification, land and water uses, and loss of biodiversity, etc. These environmental impacts can also negatively affect human health, which could in theory outweigh the health benefits of nutritious food. While better agricultural practices need to be developed and applied to minimize the environmental burdens associated with the production chains, consumers are expected to implement more sustainable lifestyles and eat more environment-friendly foods. Life Cycle Assessment (LCA) is an analytical tool to evaluate the sustainability of a product by examining all the resources used and emissions generated during its life cycle. The first part of this work focused on the upstream production. An LCA of organic blueberry production was conducted to evaluate the trade-off between seasonal and local options and answer the question of whether imported fresh or domestic frozen blueberries are more sustainable. Fresh blueberries from Chile showed superior environmental performance within 2-week storage, due to lower electricity use associated with refrigeration and higher farming yield. Furthermore, length of storage and transportation distance were also found important; if farming yields are comparable, consumption of locally produced, fresh blueberries will be a better choice because of less energy use and shorter transportation distance. The second part of this work targeted at the downstream consumption and aimed to reduce the U.S. environmental footprint through changing adult eating habits. Supplemental functional units were applied in the LCA to incorporate the functions of food to provide nutrition and satiety. With controlled caloric intake, vegetarian diets were found overall more sustainable. However, large possible variations in the environmental impacts of the compared diets were observed due to wide range of nutritional quality of selected foods. Animal products, including meat and dairy especially, and discretionary foods were identified as hotspots in the American diet, that is, reducing the consumption of these foods or deliberately choosing more sustainable alternatives within the same food categories, like chicken and low-fat milk, can significantly improve the sustainability of current American dietary patterns. <br>
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Arbuscular mycorrhizal fungi: crop management systems alter community structure and affect soybean growth and tolerance to water stressLisseth Zubieta (5930507) 03 January 2019 (has links)
<p>Arbuscular mycorrhizal
fungi (AMF) are best known for their potential to help plants acquire
nutrients, especially phosphorous. These microbes improve soil health by
promoting soil aggregation and carbon sequestration, and further benefit plants
by helping them withstand biotic and abiotic stress. Currently, there are 200
recognized species of AMF within the phylum Glomeromycota. Recent studies
indicate that individual AMF species differ in the benefits they provide, with
some even acting as parasites. Moreover, AMF community composition can be
altered by soil and crop management practices, but the effect of these changes
on the benefits conferred by AMF are still not well understood. Consequently,
the goal of this study was to determine how two widely used crop management
systems can alter the composition of AMF species, and affect the potential for
these communities to promote the productivity and drought tolerance. To
accomplish this goal, we collected AMF inoculum from a long-term crop systems
trial comparing organic and conventional management for use in greenhouse
trials where we subjected plants to drought. We collected AMF inoculum during
mid-summer when differences between the two management systems were likely
cause larger effects on AMF communities, and again in autumn after harvest to
see if differences in AMF communities would persist. We determined AMF species
composition using next generation sequencing. Results of this study confirm
that soil-building practices commonly used in organic farming systems can
improve soil health and increase the productivity of food-grade soybeans. They
also demonstrate that AMF communities in Indiana croplands are highly diverse,
and some of these taxa can improve soybean growth and help plants tolerate
water stress. Although the overall diversity of AMF communities did not differ
between the organic and conventional management systems in mid-summer,
individual AMF taxa did differ between the systems, which were likely
responsible for the greater tolerance to water stress observed when plants were
amended with inoculum from the organic system. AMF communities present during
autumn were significantly different between the two crop management systems,
but did not result in differences in drought tolerance of soybeans, indicating
that the loss of key AMF taxa in the organic system from the first relative to
the second experiment was likely responsible. Finally, plants grown using
inoculum from both crop management systems in autumn had greater tolerance to
water stress than plants that received a AMF commercial inoculum. This provides
further evidence that individual AMF species vary in the benefits they provide,
and that the presence of a diverse consortium of AMF species is needed to
optimize plant health and productivity in agricultural systems. Agricultural
producers should consider incorporating soil-building practices that are
commonly used in organic farming systems such as planting winter cover crops,
to improve the health of their soil and enhance the productivity of their
crops. <b></b></p>
<br>
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Utilization of Legacy Soil Data for Digital Soil Mapping and Data Delivery for the Busia Area, KenyaJoshua O Minai (8071856) 06 December 2019 (has links)
Much older soils data and soils
information lies idle in libraries and archives and is largely unused,
especially in developing countries like Kenya. We demonstrated the usefulness
of a stepwise approach to bring legacy soils data ‘back to life’ using the 1980
<i>Reconnaissance Soil Map of the Busia Area</i>
<i>(quarter degree sheet No. 101)</i> in
western Kenya as an example. Three studies were conducted by using agronomic
information, field observations, and laboratory data available in the published
soil survey report as inputs to several digital soil mapping techniques. In the first study, the agronomic
information in the survey report was interpreted to generate 10 land quality
maps. The maps represented the ability of the land to perform specific
agronomic functions. Nineteen crop suitability maps that were not previously
available were also generated. In the second study, a dataset of
76 profile points mined from the survey report was used as input to three
spatial prediction models for soil organic carbon (SOC) and texture. The three
predictions models were (i) ordinary kriging, (ii) stepwise multiple linear
regression, and (iii) the Soil Land Inference Model (SoLIM). Statistically, ordinary
kriging performed better than SoLIM and stepwise multiple linear regression in
predicting SOC (RMSE = 0.02), clay (RMSE = 0.32), and silt (RMSE = 0.10),
whereas stepwise multiple linear regression performed better than SoLIM and
ordinary kriging for predicting sand content (RSME = 0.11). Ordinary kriging
had the narrowest 95% confidence interval while stepwise multiple linear
regression had, the widest. From a pedological standpoint, SoLIM conformed better to the soil
forming factors model than ordinary kriging and had a narrower
confidence interval compared to stepwise multiple linear regression. In the third study, rules generated
from the map legend and map unit descriptions were used to generate a soil
class map. Information about soil distribution and parent material from the map
unit polygon descriptions were combined with six terrain attributes, to
generate a disaggregated fuzzy soil class map. The terrain attributes were
multiresolution ridgetop flatness (MRRTF), multiresolution valley bottom
flatness (MRVBF), topographic wetness index (TWI), topographic position index
(TPI), planform curvature, and profile curvature. The final result was a soil
class map with a spatial resolution of 30 m, an overall accuracy of 58% and a
Kappa coefficient of 0.54. Motivated by the wealth of soil
agronomic information generated by this study, we successfully tested the
feasibility of delivering this information in rural western Kenya using the
cell phone-based Soil Explorer app (<a href="https://soilexplorer.net/">https://soilexplorer.net/</a>). This study
demonstrates that legacy soil data can play a critical role in providing
sustainable solutions to some of the most pressing agronomic challenges
currently facing Kenya and most African countries.<div><p></p></div>
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CHARACTERIZING CYST MYCOBIOME AND BIOLOGICAL CONTROL OF THE POTATO AND SOYBEAN CYST NEMATODESBlaise Jumbam (13175475) 29 July 2022 (has links)
<p> </p>
<p>Plant-parasitic nematodes are amongst the most important pathogens impacting crops. Potatoes and soybean are vital crops for rural livelihoods and essential for food security, but their cyst nematode parasites remain a significant constraint globally. <em>Globodera</em> and <em>Heterodera </em>species are amongst the most damaging and internationally recognized quarantine pests of these crops, causing up to 80% yield loss. Their second stage juveniles (J2s) penetrate the host plant root tips and establish a residence close to the vascular bundle from where they extract nutrients as they complete their life cycle. Restrictions of control chemicals have led to an urgent need for alternative control strategies for cyst nematodes. Biological control is a promising alternative control measure, and fungi possess many characteristics that could make them great biological control agents of cyst nematodes. Most nematode populations are thought to be regulated by their natural enemy community. It is unclear which fungi are best adapted as natural enemies of these parasites and how they might do this. This project aimed to (a) characterize and compare the mycobiome diversity of cyst nematode species; (b) isolate and characterize fungi associated with potato and soybean cyst nematodes (c) screen isolated fungi for their efficacy as biocontrol agents against cyst nematodes; and (d) describe any isolated fungi identified as new and having potential for cyst nematode antagonism. Cyst populations were collected from different regions and screened for fungi using culture-based methods. For our next-generation sequence data analysis, we found differences in fungal community assemblages between center of origin of the potato cyst nematode (Peru; South America) and the regions where these nematodes were introduced such as Europe and North America. There was no significant difference in fungal community assemblages of cysts collected between the years 2019 and 2020. We characterized fungi associated with the cyst nematodes and found that the most frequently isolated genera were <em>Fusarium, Penicillium, Cylindrocarpon, Phoma, Aspergillus </em>and<em> Verticillium</em>. Filtrates from <em>Trichoderma</em> sp. 2, <em>Alternaria alternata, </em>and <em>Fusarium acaciae-mearnsii </em>were toxic on SCN eggs while <em>Purpureucillium lilacinum, Fusarium proliferatum</em> and <em>Aureobasidium</em> <em>ellingtonae </em>sp. nov. were toxic on PCN eggs and juveniles. A new species of <em>Aureobasidium</em> isolated from the potato cyst nematode (<em>Globodera ellingtonae</em>) for the first time, and having biocontrol potentials against this nematode, was also identified, and described. </p>
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Integrating Pest and Pollinator Management: Assessing the Impact of Commercial Watermelon Production on Pests and PollinatorsJohn Jay Ternest (6635369) 14 May 2019 (has links)
Fruit set in cucurbit crops such as watermelon is entirely dependent upon pollinators, which makes them an important aspect of grower management. This reliance on pollinators means that growers must consider them when making pest management decisions, especially when using pesticides, which can have a negative impact on pollinators. Thus, pest management in watermelon production faces a potential trade-off between pests and pollinators. The ways in which growers manage this trade-off could have a large impact on the communities of both groups and the yield of the crop. <br>
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Planejamento do espaço fisico e socio-economico no meio rural : uma proposta metodologica / Physical and social economical space planning in the rural sectorOliveira, Rosangela Aparecida Pereira de 20 December 2005 (has links)
Orientador: Maristela Simões do Carmo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-08T16:21:44Z (GMT). No. of bitstreams: 1
Oliveira_RosangelaAparecidaPereirade_D.pdf: 13011665 bytes, checksum: 790aa77a8771f5ebda726f779c4d24aa (MD5)
Previous issue date: 2005 / Resumo: O principal problema levantado nesta tese é que a ocupação do espaço rural para a produção agropecuária se efetiva sem a devida preocupação com os recursos naturais disponíveis, em especial o solo, e sem o conhecimento das características sócio-econômicas dos produtores. Uma das evidências para essa constatação é que ainda não há estudos suficientes sobre as dinâmicas ambientais e sociais do uso do solo, ocorrendo uma supervalorização da dimensão econômica na exploração dos mesmos. Objetivou-se realizar um estudo do meio físico, através de suas potencialidades e limitações, em sobreposição aos indicadores sócio-econômicos, com vistas a avaliar uma proposta metodológica de planejamento rural para o desenvolvimento sustentável. A partir daí procurou-se quantificar a adequabilidade do uso do solo dos municípios de Aguaí, Mogi Guaçú e Estiva Gerbi, Estado de São Paulo, para os anos de 1981, 1990 e 1997, compondo um banco de dados espaciais multitemporais. A avaliação sócio-econômica foi feita por meio da análise da dinâmica de ocupação e uso dos recursos naturais pelos agricultores, agrupados em setores censitários do IBGE, cujas variáveis e tipologia, georeferrenciadas, compuseram o banco de dados de atributos. A metodologia foi desenvolvida a partir da elaboração do Mapa de Adequabilidade do Uso do Solo dos municípios, empregando-se os Mapas de Aptidão Agrícola e de Uso e Cobertura do Solo, segundo o Método de Avaliação de Aptidão Agrícola, utilizando-se imagens dos satélites Landsat 2 (MSS) e Landsat 5 (TM). Foram também analisadas as transformações no uso dos solos pela tabulação cruzada e índices de exatidão global e Kappa, que indicam o grau de evolução nas mudanças ocorridas no espaço analisado. A caracterização sócio-econômica e tecnológica dos setores censitários foi efetivada por meio da Análise Fatorial de Correspondências Múltiplas (ACM) e da Classificação Hierárquica Ascendente, com os dados do Censo Agropecuário 1995/96. Os resultados da análise física multitemporal permitiram delimitar o histórico agroambiental do uso dos solos, representando a evolução e expansão agropecuária, em relação ao uso e adequabilidade dos mesmos. A análise espaço-temporal do uso intensivo do solo e da adequabilidade indicou uma forte evolução no sentido do aumento da ocupação dos solos, tanto para um uso adequado, quanto para uma sobreutilização. Nos três municípios, percebe-se que, com a intensificação da modernização da agricultura, as terras subutilizadas vão diminuindo, gradativamente de 1981 a 1997, apontando seu decréscimo na direção do desmatamento e/ou substituições das pastagens, para a introdução de culturas anuais e/ou permanentes, de maior valor comercial. Por outro lado, áreas que deveriam estar como reservas para preservação permanente acabam também sendo apropriadas por cultivos mais intensivos, ocorrendo, novamente, uma sobreutilização do solo. Foram definidos quatro tipos de agricultores nos municípios: modernos e diversificados citrícolas capitalizados, criadores descapitalizados de animais e familiares com produção vegetal diversificada. Como resultado final, obteve-se um conjunto de mapas, que traduzem o conhecimento integral dos espaços rurais e a ocupação do território. A metodologia proposta mostrou-se apropriada para o subsídio ao planejamento sócio-ambiental, propiciando elementos para um diagnóstico atualizado e eficaz, no estabelecimento de políticas públicas voltadas ao desenvolvimento rural sustentado / Abstract: The main problem raised in this thesis is that the occupation of the agricultural space for the farming, effectives production without the proper concern with the available natural resources, in special the ground, and without the knowledge of the social and economical characteristics of the producers. One of the causes for this confirmation is that it does not have enough studies yet on the environmental and social dynamic of the use of the land, occurring a supervaluation of the economic dimension in the exploration of agricultural ground. It was aimed to carry through a study of its potentialities and limitations, in overlapping to the social and economical index, with sights to evaluate a methodological proposal of agricultural planning for the sustainable development. Since then, it was tried to quantify the adequateness of the use of lands of the cities of Aguaí, Mogi Guaçú and Estiva Gerbi, State of São Paulo, for the years of 1981, 1990 and 1997, composing a multisecular space data base. The social and economical evaluation was made by the analysis of the dynamics of occupation and use of the natural resources for the agriculturists, grouped in tax sectors of the IBGE, whose georeferenced variable and typology had composed the bank of attributes. The methodology had as base the elaboration of the Map of Adequateness of the Use of Lands of the cities, using the Maps of Agricultural Aptitude and the Use and Covering of the Ground, according to Method of Classification of Agricultural Aptitude, using images of the satellites Landsat 2 (MSS), Landsat (5 TM) and Landsat 7 (ETM+). Also the transformations in the use of lands for the cross tabulation and index of global exactness and Kappa had been analyzed, that indicate the degree of evolution in the occured changes in the analyzed space. The social, economical and technological characterization of the tax sectors was accomplished by means of the Factorial Analysis of Correspondence (ACM) and the Ascending Hierarchic Classification, with the data of 1995/96 Farming Census. The results of the multisecular physical analysis had allowed to delimit the agro-environmental description of the use of the land, being represented the evolution and farming expansion in relation to the use and adequateness of lands. The analysis space-weather of the intensive use of the ground and the adequateness, indicated one strong evolution in the direction of the increase of the occupation of lands, as much for an adjusted use as for an over-use. In the three cities, it was perceived gradually that, with the intensification of the modernization of agriculture, the underutilized lands diminished, from 1981 to 1997, pointing its decrease in the direction of the deforestation and/or substitutions of the pastures with respect to the introduction of annual and/or permanent cultures of higher commercial value. On the other hand, lands that would have to remain as reserves for permanent preservation also finishing being appropriate for more intense cultivation, occurring, again, an over-use of the lands. Four types of agriculturists in the cities had been defined: modern and diversified, capitalized citrus producers, undercapitalized animal breeders, diversified familial vegetal production. As final result, a set of maps was gotten, aiming at the integral knowledge of the agricultural spaces and the occupation of the territory. The methodology proposal revealed appropriate for the subsidy to the spcial and environmental planning, propitiating elements for a fast, brought up to date and efficient diagnosis, in the establishment of directed public politics to the supported agricultural development / Doutorado / Planejamento e Desenvolvimento Rural Sustentável / Doutor em Engenharia Agrícola
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USING HYPERSPECTRAL IMAGING TO QUANTIFY CADMIUM STRESS AND ESTIMATE CONCENTRATION IN PLANT LEAVESMaria Zea Rojas (8415870) 30 July 2020 (has links)
<p>Cadmium (Cd) is a highly mobile and toxic heavy metal that negatively affects plants, soil biota, animals and humans, even in very low concentrations. Currently, Cd contamination of cocoa produced in Latin American countries is a significant problem, as concentrations can exceed acceptable levels set by the European Union (0.5 mg/kg), sometimes by more than 10 times allowable levels. In South America, <i>Theobroma cacao</i> is an essential component of the basic market basket. This crop contributes to the Latin-American trade balance, as these countries export cacao and chocolate-based products to major consumer countries such as the United States and Europe. Some soil amendments can alter the bioavailability and uptake of Cd into edible plant tissues, though cacao plants can accumulate Cd without displaying any visible symptoms of phytotoxicity, which makes it difficult to determine if potential remediation strategies are successful. Currently, the only effective way to quantify Cd accumulation in plant tissues is via destructive post-harvest practices that are time-consuming and expensive. New hyperspectral imaging (HSI) technologies developed for use in high-throughput plant phenotyping are powerful tools for monitoring environmental stress and predicting the nutritional status in plants. Consequently, the experiments described in this thesis were conducted to determine if HSI technologies could be adapted for monitoring plant stress caused by Cd, and estimating its concentration in vegetative plant tissues. Two leafy green crops were used in these experiments, basil (<i>Ocimum basilicum L.</i> var. Genovese) and kale (<i>Brassica oleracea L</i>. var. Lacinato), because they are fast growing, and therefore, could serve as indicator crops on cacao farms. In addition, we expected these two leafy green crops would differ in their morphological responses to Cd stress. Specifically, we predicted that stress responses would be visible in basil, but not kale, which is known to be a hyperaccumulator. The plants were subject to four levels of soil Cd (0, 5, 10 and 15 ppm), and half of the pots were amended with biochar at a rate of 3% (v/v), as this amendment has previously been demonstrated to improve plant health and reduce Cd uptake. The experiments were conducted at Purdue’s new Controlled Environment Phenotyping Center (CEPF). The plants were imaged weekly and manual measurements of plant growth and development were collected at the same times, and concentrations of Cd as well as many other elements were determined after harvest. Fourteen vegetation indices generated using HSI images collected from the side and top view of plants were evaluated for their potential to identify subtle signs of plant stress due soil Cd and the biochar amendment. In addition, three mathematical models were evaluated for their potential to estimate Cd concentrations in the plant biomass and determine if they exceed safe standards (0.28 mg/kg) set by the Food and Agriculture Organization (FAO) for leafy greens. Results of these studies confirm that like many plants, these leafy green crops can accumulate Cd levels that are well above safety thresholds for human health, but exhibit few visible symptoms of stress. The normalized difference vegetation index (NDVI) and the chlorophyll index at the red edge (CI_RE) were the best indices for detecting Cd stress in these crops, and the plant senescence and reflectance index (PSRI) and anthocyanin reflectance index (ARI) were the best at detecting subtle changes in plant physiology due to the biochar amendment. The heavy metal stress index (HMSSI), developed exclusively for detecting heavy metal stress, was only able to detect Cd stress in basil when images were taken from the top view. Results of the mathematical models indicated that principal components analysis (PCA) and partial least squares (PLS) models overfit despite efforts to transform the data, indicating that they are not capable of predicting Cd concentrations in these crops at these levels. However, the artificial neural networks (ANN) was able to predict whether leafy greens had levels of Cd that were above or below critical thresholds suggested by the FAO, indicating that HSI could be further developed to predict Cd concentrations in plant tissues. Further research conducted in the field and in the presence of other environmental stress factors are needed to confirm the utility of these tools, and determine whether they can be adapted to monitor Cd uptake in cacao plants.</p>
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Perceptions of Food Safety and of Personal Capability, Opportunity, and Motivation for Food Safety Practices Among Cambodians Involved with Informal Vegetable MarketsSabrina R Mosimann (14231084) 07 December 2022 (has links)
<p>Poor food safety in informal, open-air markets remains a pressing issue in Cambodia, contributing to both foodborne illness and malnutrition. In order to design food safety programs that successfully promote positive food safety practices among the various actors involved in these markets, is important to understand their perceptions of food safety and of their own capability, opportunity, and motivation for adopting positive food safety behaviors. To that end, this research sought to explore and describe the perceptions of vegetable vendors, vegetable distributors, and vegetable growers in the Cambodian provinces of Battambang, Siem Reap, and Phnom Penh regarding food safety and their own personal capability, opportunity, and motivation for implementing specific food safety practices. To note, this research was made possible by the generous support of the American people through the United States Agency for International Development (USAID) though Cooperative Agreement No. 7200AA19LE00003 to Purdue University as management entity of the Feed the Future Innovation Lab for Food Safety. The contents are the responsibility of the authors and do not necessarily reflect the views of USAID or the United States Government. </p>
<p>The first portion of the research, which examined levels of perceived capability, opportunity, and motivation for positive food safety practices among actors involved in informal vegetable markets in Cambodia, employed a quantitative questionnaire based on the Capability, Opportunity, Motivation-Behavior model of behavior and the Theoretical Domains Framework. A pilot study using this questionnaire was performed with vegetable vendors in the Province of Phnom Penh (<em>N</em> = 55), after which the questionnaire was revised and implemented in person with vegetable distributors in Battambang Province (<em>n</em> = 37) and vegetable vendors and growers in Battambang (<em>n</em> = 26 and <em>n</em> = 27, respectively) and Siem Reap Provinces (<em>n</em> = 61 and <em>n</em> = 30, respectively). To validate the questionnaire, response data from participants in Battambang and Siem Reap were evaluated using confirmatory factor analysis. The resultant nine-factor model had a comparative fit index of .91, a Tucker-Lewis index of .89, and a root mean square error of approximation of .05. Data analysis proceeded using a fitted general linear mixed model. Results of this analysis suggested that levels of perceived motivation and capability for the target food safety practice were typically significantly higher (<em>p</em> < .05) than levels of perceived opportunity among vegetable vendors and distributors, regardless of location. Levels of perceived opportunity and perceived capability were significantly lower (<em>p</em> < .05) than levels of perceived motivation among vegetable growers in both Battambang and Siem Reap. Significantly higher (<em>p</em> < .05) levels of perceived opportunity and motivation for the target food safety practice were observed among vendors in Battambang in comparison to vendors in Siem Reap; perceptions of all three behavioral determinants were higher among vendors in Battambang than among farmers in either location. </p>
<p>Subsequently, a quantitative questionnaire regarding participants’ perceptions of vegetable safety was implemented in person with vegetable growers in Battambang (<em>n </em>= 41) and Siem Reap (<em>n</em> = 28) and vegetable vendors in Phnom Penh (<em>n </em>= 31). Response data were analyzed using a fitted logistic regression model. Nearly all respondents indicated that they were concerned about vegetable safety (overall mean estimate 97.4%, 95% CI = [89.7, 99.4]%), with ≤ 62.7% of respondents in all groups reporting at least moderate concern (lower bounds of 95% confidence intervals 46.2% at the lowest). Across all groups, chemical contamination was perceived as more concerning than microbial contamination (84.9%, 95% CI = [76.0, 90.9]%). The majority of respondents reported that they were familiar with the potential health effects of consuming vegetables contaminated with either chemicals (71.4% [61.5, 79.6]%) or microbes (57.3% [47.2, 66.9]%). Nonetheless, when those who reported familiarity were asked to give examples of such health effects, fewer than 50% (ranging from 7.3% to 48.4%) provided an example of a commonly understood health effect of consuming contaminated vegetables. </p>
<p>Both chemical and microbial contamination were most frequently perceived as occurring mainly “at the farm”, regardless of participants’ occupation and location (≥ 76.7%, lower bounds of 95% confidence intervals at least 61.5%, and ≥ 39.3%, lower bounds of 95% confidence intervals at least 21.2%, respectively). Correspondingly, “vegetable farmers’ were most often perceived as having the greatest responsibility for chemical contamination prevention (≥ 51.6% across all groups, lower bounds of 95% confidence intervals at least 34.0%). There were significant between-group differences in participants’ perceptions of microbial contamination prevention responsibility, however (<em>p</em> = .02). With regards to practices intended to prevent vegetable contamination, 22.6% of surveyed vendors in Phnom Penh, 39.0% of surveyed growers in Battambang, and 53.6% of surveyed growers in Siem Reap described at least one commonly accepted contamination prevention practice. </p>
<p>Considered as a whole, these findings indicate that food safety practice adoption may be more effectively encouraged among vegetable growers, distributors, and vendors in Phnom Penh, Battambang, and Siem Reap by emphasizing the importance of microbial contamination and integrating educational components regarding the health effects of consuming vegetables contaminated with microbes or chemicals into food safety programs. Such programs should also address the relatively lower levels of perceived opportunity present among all groups; environmental restructuring-based interventions may be one means by which to do so. Programs for vegetable vendors specifically should communicate that microbial contamination of vegetables is common and highlight the significance of the role of vegetable vendors in maintaining a safe vegetable supply. Food safety programs tailored to vegetable growers could draw on growers’ perception of their own responsibility for both vegetable contamination and contamination prevention as well as their perception of contamination as a common occurrence. Programs for vegetable growers also need to incorporate efforts to address the relatively lower levels of perceived capability present within this group. These efforts could include educational programming or hands-on demonstrations that increase participants’ perceptions of their own ability to implement positive food safety practices. </p>
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Developing Selective Lures to Optimize Striped Cucumber Beetle (<i>Acalymma vittatum</i>) Management by Combining Pheromone and Plant VolatilesRachel A Youngblood (18432096), Ian Kaplan (10232781), Donald C. Weber (3178635), Matthew Ginzel (8771376) 30 April 2024 (has links)
<p dir="ltr">The striped cucumber beetle (<i>Acalymma vittatum</i>) is a leading pest across a variety of cucurbit crops in eastern North America. These beetles can rapidly infest and damage a field, leading to frequent insecticide applications to manage them. Chemical control is effective at reducing beetle populations, but it also causes detrimental non-target effects on pollinators, which are essential for cucurbit yield. Developing a holistic IPM (integrated pest management) approach is necessary to manage pests while avoiding non-target effects in cucurbit production systems. </p><p dir="ltr">A unique and well-characterized behavior of striped cucumber beetles is their olfactory attraction to both plant volatiles and their species-specific aggregation pheromone, vittatalactone. The interacting effects of combining these olfactory stimuli for cucumber beetle attraction have not previously been tested. I expected when presented with plant volatiles and pheromone together, the striped cucumber beetles will show synergistic attraction, resulting in enhanced attraction stronger than the sums of the separate effects. Along with targeting striped cucumber beetles, I expected to elicit cross-attraction of related cucurbit pests (e.g., spotted cucumber beetle) to these same signals based on previous findings indicating cross-attraction. The expected cross attraction may be due to the reliance on olfactory cues to inform the related insects on preferrable host plants and nutrition. </p><p dir="ltr">Cucurbit systems are also highly reliant on pollination services for high-quality fruit; thus, the feasibility of these semiochemical tools depends on their influence on pollinator behavior. I expect pollinators to be attracted to floral volatiles but not vittatalactone or individual plant volatiles without the full complement of floral scent (e.g., indole, leaf volatiles). Altogether, this research aims to develop a targeted management tool for striped cucumber beetles and other cucurbit pests, while avoiding pollinator distraction or other detrimental effects.</p><p dir="ltr">To measure the efficacy of using olfactory signals as attractants, clear sticky cards were deployed in the field with combinations of pheromone paired with volatiles (floral and/or leaf), as well as the individual components, to quantify pest responses. Simultaneously, a pan trap sampling method was implemented to measure pollinator responses to the same semiochemical combinations. The results of the study demonstrate that striped cucumber beetles are strongly attracted to volatile lures containing pheromones, floral volatiles, and combinations of the two, although the combined pheromone and floral volatile treatments did not synergize beetle attraction. </p><p dir="ltr">Though combined lures did not synergize attraction, this data demonstrates additive effects on beetle behavior. The findings also highlight the importance of understanding seasonal disparities between the behavior of early and late generations of striped cucumber beetles. Temporal variation in attraction demonstrated by the pests is crucial to understand when to implement lure-based management strategies. Two years of testing floral volatile and herbivory-induced plant volatile (HIPV) lure treatments on key cucurbit pollinators showed varying levels of attraction. There was no attraction of focal cucurbit bees to the striped cucumber beetle pheromone, but there were differences in the response of pollinators to plant volatile components. </p><p dir="ltr">Cucurbits require high pollination activity for successful fruit, though the most important bees in pollinating this system are bees belonging to the genera, <i>Apis</i> and <i>Eucera</i>. Along with these bee groups, other bees such as those belonging to <i>Melissodes</i>, <i>Lasioglossum</i>, and <i>Bombus</i> are also known important pollinators. <i>Lasioglossum</i> bees showed a strong attraction to the full-floral blend, TIC (1,2,4-trimethoxybenzene, indole, (E)-cinnamaldehyde), but no preference for indole or HIPVs. <i>Melissodes</i> bees were most attracted to methyl salicylate and TIC, whereas <i>Eucera</i> bees exhibited strong attraction to ocimene and TIC. These findings suggest that different pollinator taxa have unique preferences for plant volatiles, highlighting the importance of optimizing lure combinations to avoid disrupting pollination activities in cucurbit production.</p><p dir="ltr">Additionally, this study revealed that other key cucurbit pests, such as spotted cucumber beetles and western corn rootworms, also showed strong attraction to the tested volatile components. These findings suggest that the selected volatiles may have broader implications for pest management beyond striped cucumber beetles. Further research is needed to fully understand the efficacy and refine formulations of these volatile lures to implement in IPM.</p>
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