Online Master of Agricultural and Life Sciences
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The Online Master of Agricultural and Life Sciences (OMALS), http://www.cals.vt.edu/online/, is uniquely positioned to meet the evolving and dynamic needs of today’s agricultural professionals. The program offers concentrations in the areas of agribusiness, applied animal behavior and welfare, applied nutrition and physical activity, education, environmental science, food safety and biosecurity, and leadership studies, as well as plant science and pest management. In addition to engaging classes, students benefit from the opportunity to work on-on-one with well-respected faculty in Virginia Tech's College of Agriculture and Life Sciences to complete a rigorous final project, using what they've learned and developing real-world research and communication skills. This collection showcases final projects completed by current and former OMALS students.
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Browsing Online Master of Agricultural and Life Sciences by Department "Entomology"
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- Developing and Using an Ethnographic Linear Programming Model of the Small Farm Livelihood System of Bohoc, HaitiSlaughter, Robert Carroll (Virginia Tech, 2012-05)This project involved the development of an Ethnographic Linear Programming (ELP) model for the small farm livelihood system of the village of Bohoc, Haiti, and using the model to pre-evaluate the biological control of the sugarcane mealybug (Saccharicoccus sacchari) with one of its natural enemies, Cryptolaemus montrouzieri. This required three phases of field research: (1) a Sondeo or participatory rural appraisal to form an understanding of the livelihood systems in this part of the Central Plateau of Haiti, (2) intense interviews of a representative Bohoc farm family, and (3) interviews of four other Bohoc farm families to validate or complement the data obtained from the first family. The first draft of the ELP matrix was prepared after phase two, and the matrix was revised and expanded after phase 3. The ELP matrix accurately models the crops grown and other income-producing activities engaged in by the farm families, but may understate the percentage of available labor used and may overstate the cash accumulated. It is uncertain whether further research would enhance the accuracy of the ELP model. Despite its possible limitations, the matrix that was developed is viewed as a useful tool for understanding the small farm livelihood system that it modeled and for pre-evaluation or hypothesis testing of new agricultural activities, technologies, products, policies, or infrastructures. The pre-evaluation of biological control of the sugarcane mealybug was beneficial for purposes of illustrating the use of the ELP model, but an actual pre-evaluation of this would require further study.
- Documenting Population Fluctuations of Vine Mealybug in Chardonnay Vines Influenced by Environmental Conditions, Insecticide Programs, Vine Phenology, and WeedsTrujillo, Maritza; Pfeiffer, Douglas G.; Del-Pozo, Alejandro; Taylor, Sally V. (Virginia Tech, 2023-03-03)Vine mealybugs (VMB) are a key pest to coastal vineyards in California. They can cause major issues to host plants during all their life stages due to their mouthparts and reproduction. Chardonnay, a highly VMB-susceptible variety at Delicato Family Wines, was chosen for this study to document fluctuations of this pest. Selected commercial blocks had different soil textures, vine phenology, weed types, VMB previous infestation history, topography, mechanical and chemical practices. Block 218A had moderate population levels, with sooty mold. Block 41B had high mealybug populations with some sooty mold but not as much as 218A (it is also a younger block than 218A). Block 96A, the youngest block, had no VMB presence from May-early August 2022 but had one highly infested vine during the last few weeks of August. Pheromone traps were also placed in these blocks to monitor males. When counting numbers in all traps, the trap closest to the highly infested vine in 96A had the most captured males throughout this study. After documenting all findings, it seemed like mealybugs prefer cooler shaded areas especially when temperatures are warm. In conclusion, management of weeds, sanitizing equipment after going into a field, and proper insecticide timing with the use of growing degree days, will assist in having better management of VMB. These practices can reduce the chances of sudden population growth, and continuous reproduction that may lead to sooty mold and possible vectored diseases such as leaf curl and red blotch.
- Egg Safety: Control Factors of SalmonellosisWier, Deborah (Virginia Tech, 2013-05)Salmonella enterica serotype Enteritidis (SE) continues to be one of the most commonly identified bacteria associated with outbreaks of human salmonellosis around the world, particularly in developed countries (CDC, 2011). In the United States, salmonellosis is a common infection with occurrences reaching up to 1.4 million in a year (Braden, 2006). From May to November of 2010, approximately 1,983 illnesses were reported and associated as a result of a single Salmonella spp outbreak detected in the United States (CDC, 2011). The source of the outbreak was traced to Wright County Egg in Galt, Iowa and subsequently led to the voluntary recall of 380 million eggs distributed throughout the country. Hillandale Farms, also in Iowa, voluntarily recalled another 170 million eggs (CDC, 2011). Identifying the source of the outbreak was the result of coordinated investigations by the Center for Disease Control (CDC), local public health authorities and the Food and Drug Association (FDA). According to the United Egg Producer’s (UEP) website, the chance of eggs containing SE is rare in the United States. Estimates are 1 in 20,000 eggs might be contaminated with SE (UEP, 2010; Guard-Petter, 2001). This would mean that a consumer would encounter an infected egg once in 84 years. The number is also claimed to be decreasing due to the increased protection measures adapted by egg producers over the past decade. Improved sanitary housing systems, vaccinations and cleaning processes have all led to the claim of decreased cases of SE throughout the nation (Braden, 2006; UEP, 2010; Patrick, et al., 2004). The use of average outbreaks can be misleading due to the nature of infection and their correlation to single producer outbreaks. Investigation into SE outbreaks between 1985 and 1999 by Patrick, et al., 2004 concluded that outbreaks of SE infections in human decreased by almost 50% between 1995 and 1999. These reports may have left people feeling like things were on the right track, then the Wright County Egg incident occurred. Without constant vigilance and willingness to incorporate new ideas, the next big outbreak is around the corner. This paper will look at the various methods available to increase the quality of eggs and integrating those ideas into a viable program to fortify public safety.
- Evaluating the performance of Orius insidiosus as a predator of thrips in greenhouse-grown geraniumsEpes, Chris M. (Virginia Tech, 2021-07-16)Thrips are among the most common and economically damaging greenhouse pests in the world. Due to the demanding nature of chemical control programs in greenhouses for thrips, biocontrol strategies are growing in popularity in greenhouse pest control programs. Geraniums are common in spring annual greenhouse production programs, and like many other crops demand thrips management strategies. This project lays the groundwork for exploring the performance of minute pirate bug, Orius insidiosus, to reduce thrips densities in greenhouse geraniums. In a laboratory, Orius and thrips were released into controlled, no-choice predation arenas using both geranium leaves and flowers, and thrips mortality was assessed. Orius and thrips were then released onto finished potted geranium plants under no-choice conditions in insect cages under greenhouse conditions, after which thrips mortality was assessed. The cumulative results show that Orius prey upon thrips on geranium leaves and florets, and could be used as a tool to help reduce thrips populations in greenhouse-grown geraniums.
- Evaluation of a Revised Protocol for Stall Terminations in the Large Animal HospitalPrice, Allison B. (Virginia Tech, 2019-06-24)Cleaning and disinfection are critical areas of Veterinary hospital biosecurity. Without a validated biosecurity program, veterinary hospitals are in a vulnerable state. Potential outbreaks of pathogenic microorganisms could occur causing loss of: patient lives, hospital revenue and hospital prestige. Instances of pathogenic outbreaks have been recorded in small animal settings (i.e. veterinary clinics and shelters) and in large animal settings (i.e. farms and hospitals.) Veterinary hospitals, often considered the gold standard of veterinary care are not immune to biosecurity breaches. In last 5 years 82% of veterinary teaching hospitals reported nosocomial infections (Anderson, 2010). The aim of this project was to validate cleaning and sanitation procedures that are already in place in the Harry T. Peters, Jr. Large Animal Hospital located in Blacksburg, VA. This project compared two sanitation protocols and validated them using environmental sampling. Using chi-square analysis results indicated there was no significant difference between the sanitation methods.
- Evaluation of Consumer Food Safety Behaviors at HomeReynolds, Julia (Virginia Tech, 2018-08-02)Foodborne pathogens are a major source of illness in the United States. In 2010, the Centers for Disease Control and Prevention (CDC) estimated that 1 in 6 Americans are sickened by a foodborne illness each year. While many steps in the farm to table process are well researched and regulated, little information is known about the time between purchase and plate. This study evaluated current food safety recommendations made by the Partnership for Food Safety Education on FightBAC.org. An online survey of consumers was conducted to determine how often they perform the recommended practices to reduce the risk of foodborne pathogens at home. A total of 1,034 consumers responded to the survey. The majority of respondents indicate they practice good personal hygiene, take steps to reduce cross contamination, and store food properly. Safe handling and proper cooking of meat and poultry are areas where consumers are inconsistent and knowledge of recommended practices could be reinforced to decrease the risk of foodborne illness.
- Exploring Chemical Management of Threecornered Alfalfa Hopper in Mid-Atlantic US SoybeanPittman, Elizabeth (Virginia Tech, 2022-12-19)Threecornered alfalfa hopper, Spissistilus festinus (Say) (Hemiptera: Membracidae), is a ubiquitous pest of soybean that causes yield loss in certain scenarios. Plant lodging, and significant stand loss, from this insect has occurred in Virginia’s piedmont since at least 2017. There is a need to determine if chemical control (e.g., foliar and or seed applied insecticides) can be used to minimize plant injury and preserve yield. We hypothesized that control with insecticides will vary depending on infestation timing, which is not known, and foliar insecticides will provide the best control when applied at or near the time pests arrive. In 2021, we evaluated spray timings based on plant development and estimated infestation timings using yellow sticky traps and timed visual observations. We identified two population peaks potentially related to herbicide applications and small grain harvest. No insecticide application yielded higher than unsprayed plots and there was high variability within treatments.
- Field survey of Drosophila suzukii (Matsumura) and Zaprionus indianus Gupta (Diptera: Drosophilidae) in Maui, HawaiiWillbrand, Brittany N. (Virginia Tech, 2019-04-18)Drosophila suzukii (Matsumura) and Zaprionus indianus Gupta (Diptera: Drosophilidae) are notable agricultural pests of soft-skinned fruits. Efficient field surveying is vital in an integrated pest management program. A survey to identify D. suzukii populations was conducted in four localities in Maui County among seven host-plants. During the survey, adult Z. indianus specimens were collected at all four localities in traps positioned in six of the seven host plants, suggesting that this previously unreported exotic species may already be well-established. Though there are currently no species-specific attractants available for D. suzukii or Z. indianus, characterization of attractant specificity by species and understanding how attractant efficacy varies with time is needed to advance development. A modification of the deli-cup trap was used and five attractants (brown rice vinegar, apple cider vinegar, red wine, brown rice vinegar plus red wine, apple cider vinegar plus red wine) were deployed in cherimoya in Kula, Maui, Hawaii. This investigation includes the first reported use of brown rice vinegar as an olfactory attractant in the United States and the results suggest that it may have higher specificity in the field capture of D. suzukii than apple cider vinegar, red wine, and apple cider vinegar with red wine. No significant differences were observed in attractant specificity for the field capture of Z. indianus. To examine attractant efficacy over time with and without a preservative, traps were maintained daily in cherimoya. The results suggest that attractants up to seven days old had a significant effect on mean field captures of D. suzukii and non-target drosophilids. Inclusive of all attractants and field ages, The addition of 1% boric acid (w/v) to the attractant solution increased the total field captures of D. suzukii by 44%, but no effect was observed for non-target drosophilids. These investigations enhance our current understanding of attractant specificity, which is the first step towards identifying selective compounds for a species-specific attractant. Furthermore, the first report of Z. indianus in Hawaii highlights the importance of examining interspecies interactions between endemic and invasive drosophilids and the need for the establishment of economic thresholds for vinegar fly pests.
- Forest stand characteristics of Jefferson National Forest that observed gypsy moth defoliation from 2015-2019 in southwestern VirginiaTurner, Brandon (Virginia Tech, 2021-01-27)The gypsy moth (Lymantria dispar L., Lepidoptera: Erebidae) is an invasive forest pest that has greatly impacted oak dominated forest stands in the northeastern United States. The pest, introduced in the 1860s in Massachusetts, has spread significantly north, south, and west. The National Gypsy Moth Slow the Spread (STS) limits its spread by targeting isolated, low-density gypsy moth populations with aerial applications of insecticides and/or pheromones. Other activities by state and federal agencies include conducting aerial and ground-truth surveys of forest stand injury, resulting from gypsy moth defoliation. Annually, thousands of forested acres across the Commonwealth of Virginia are defoliated by gypsy moths. This survey was conducted to compare and identify some forest stand characteristics of infested (outbreak) and uninfested (control) areas of Virginia that could be used to predict further gypsy moth defoliation. All of the research sites were located in southwestern Virginia in close proximity to the Jefferson National Forest. The survey found stand density index, proportions of defoliation per site, and total basal area per acre of preferred host trees with gypsy moth injury to be significant factors in examining forest susceptibility. This research should be continued to further analyze these forest characteristics and help predict where future stand defoliation could occur.
- Report-U.S. Foodborne Listeria Outbreaks, 2000 to 2020Bastola, Saroj (Virginia Tech, 2023-05-15)Various food-borne Listeria outbreaks were studied between 2000 to 2020. Listeria monocytogenes symptoms might take up to 12 weeks to be reported as an outbreak. The highest food category contributor for the outbreaks was found to be Dairy contributing 43% of the outbreaks. The known highest outbreak originations for the outbreak were from restaurant facilities. Listeriosis could be prevented at home by washing hands regularly with soap and water while handling raw food, washing fruits and vegetables before eating them, storing ready-to-eat food as suggested on the label, keeping raw and ready-to-eat foods separately to avoid cross-contamination, using food by their use-by-date, and consuming ready to eat food within four hours of being taken out of the fridge. Good Agricultural Practices (GAP), good manufacturing practices (GMP), and HACCP must be implemented to reduce the risk of Listeria in food manufacturing facilities. Steps with critical control points for targeted pathogens play an important role in pointing and treating to reduce/eliminate the risk. In the food service industry food products might be contaminated with Listeria if they have not been purchased from a reliable source, this will increase the chance of cross-contamination if not stored properly. Any form or media that might be the potential for transferring the Listeria from the environment like, metal, wood, plastic, and other chemicals should be handled carefully in the working environment to reduce the risk.
- A Survey of Aphid Species and their Associated Natural Enemies in Fraser Valley Hop Fields and an Exploration of Potential Alternative Summer Hosts of the Damson-Hop Aphid, Phorodon humuli (Hemiptera: Aphididae)Carmichael, Emily J. (Virginia Tech, 2020-05-19)Six hop fields, Humulus lupulus (Rosales: Cannabaceae), in the Fraser Valley, British Columbia, were surveyed throughout 2019 to determine the composition of aphid species and their associated natural enemies. The host range of a known aphid pest of hops, the damson-hop aphid, Phorodon humuli (Hemiptera: Aphididae), was also explored in order to further clarify its summer host range and lifecycle. Phorodon humuli collected from Prunus spp. were reared and transferred to potential alternative hosts including Cannabis sativa (Rosales: Cannabaceae) and nettle, Ultica dioic (Rosales: Urticaceae). Phorodon humuli was the dominant aphid species found in all six hop fields in 2019, comprising 99% of all aphids found. Phorodon humuli were found in hop fields from May 24, 2019 through to November 3, 2019. Other aphid species were present in some hopyards early in the season including Aphis fabae (black bean aphid), Macrosiphum euphorbiae (potato aphid) and Brachycaudus helichrysi (leaf-curling plum aphid). Phorodon cannabis (hemp/cannabis/bhang aphid) was not found in any of the six hop fields. Ladybird beetles (Coleoptera: Coccinellidae) were the most abundant predator found on hop leaves, making up 76% of all aphidophagous predators found in the six hop fields. Orius spp. were the most abundant predator found in hop burrs and cones, contributing to 97% of all aphidophagous predators found in the six hop fields. Predator population growth was low compared to aphid population growth. In host-transfer experiments, P. humuli decreased on cannabis and nettle, while increased on hops, indicating that cannabis and nettle are not a preferred summer hosts of P. humuli.