Dissertations / Theses on the topic 'Pest management'

Master of Science
Entomology
Brian McCornack
Several lepidopteran species infest developing panicles. Larval identification is challenging and time intensive, so current recommendations are often simplified by treating all larvae equally across species. Consequently, the yield-loss model developed for corn earworm (Helicoverpa zea) by Buckley and Burkhardt (1962) has been the foundation for management recommendations in modern sorghum Integrated Pest Management (IPM) programs for the last 49 years. Additionally, although pest populations primarily include both fall armyworm (Spodoptera frugiperda) and corn earworm, only a single species damage estimate is used in economic threshold (ET) and economic injury level (EIL) calculations despite multi-species infestations. This research demonstrates both the validation of current management recommendations for corn earworm and the verification of previously assumed damage potentials for fall armyworm feeding in developing sorghum panicles. These results have important implications for sorghum producers faced with making a management decision for multi-species infestations.

7 pp.
Melon production in the Southwestern United States occurs primarily in the desert growing areas of Arizona, and Southern California. Melons in Arizona are grown in very diverse cropping systems, where a variety of vegetable, agronomic and seed crops are cultivated concurrently throughout the year. Numerous insect species can be found on melon plants, but only a few have been determined to be economically important. This publication discusses several key insects that cause economic damage to melons, and the tactics commonly used to manage infesting populations.

Foliar-applied insecticides and the soil-applied insecticide, Admire, were evaluated for their ability to control citrus mealybug on lemons while having a minimal impact on parasitoids. All of the foliar-applied insecticide exhibited activity towards citrus mealybug. The standard insecticide, Lorsban, performed very well, but since this product is especially harmful to parasitoids it is not considered to have a good fit in IPM programs where parasitoid conservation is emphasized. The currently labeled alternative, Applaud, was an effective treatment and should be considered for citrus mealybug control to avoid destruction of parasitoids. Several experimental insecticides showed promise: NNI-850, NNI-750C and NNI-010. However, NNI-0101 at the lower rate of 0.24 lbs-ai/ac appeared to be weak. The addition of narrow range crop oil, NR-415 at 1.0 gal/ac, appeared to be beneficial for initial mealybug knock-down, especially for the slower acting insecticides such as Applaud. Soil injection of Admire at 16 and 32 oz/ac appeared to have very good activity, but due to variability in the mealybug population, more data should be collected to confirm this finding.

This research is a study of pest management systems in Malmö. Malmö is, as many other cities, growing and a node of people's movement. Occurrences of pests have increased in the last decade; this increase is attributed to travel as well as construction and building.What this paper shows is that the structures of pest management must evolve to be more communicative and collaborative. The thesis also adds to the housing crisis debate, as pests in one’s housing have a physical as well as psychological effect.

For the first time in many decades, a hemp pilot program was initiated in Virginia in 2016. Outdoor surveys were conducted in the 2017 and 2018 field seasons to record insect presence and feeding injury to plants. Multiple insect pests were present, including corn earworm (Helicoverpa zea [Boddie]) (Lepidoptera: Noctuidae), brown marmorated stink bug (Halyomorpha halys [Stål]) (Hemiptera: Pentatomidae), and cannabis aphid (Phorodon cannabis) (Hemiptera: Aphididae). In 2019, indoor production surveys revealed that cannabis aphid, twospotted spider mite (Tetranychus urticae Koch) (Acari: Tetranychidae), and hemp russet mite (Aculops cannabicola [Farkas]) (Acari: Eriophyidae) would likely cause production issues. Very little is known about the impact of insect defoliation in hemp so studies were conducted in 2018-2020 to determine impacts on yield and cannabinoid content of grain and cannabinoid variety hemp due to leaf surface area loss. In Virginia over two growing seasons, manual removal of leaf tissue in grain and CBD cultivars did not significantly impact observable effects on physical yield (seed or bud weight) or cannabinoid content (CBD or THC) at time of harvest. Corn earworm is the major pest of hemp produced outdoors and studies occurred to evaluate monitoring and management strategies. Pheromone traps may be valuable in determining when corn earworm moths are present in the vicinity of hemp fields but are not useful in predicting larval presence in buds or final crop damage. Larval presence and final crop damage are related. Brown marmorated stink bug does not appear to be a concern in hemp, at least at this time.
Doctor of Philosophy
For the first time in many decades, a hemp pilot program was initiated in Virginia in 2016. Outdoor surveys were conducted in the 2017 and 2018 field seasons to record insect presence and feeding injury to plants. Multiple insect pests were present, including corn earworm, brown marmorated stink bug, and cannabis aphid. In 2019, indoor production surveys revealed that cannabis aphid, twospotted spider mite, and hemp russet mite would likely cause production issues. Very little is known about the impact of leaf area loss due to insect feeding in hemp so studies were conducted in 2018-2020 to determine impacts on yield and cannabinoid content of grain and cannabinoid variety hemp due to leaf surface area loss. In Virginia over two growing seasons, manual removal of leaf tissue in grain and CBD cultivars did not significantly impact observable effects on physical yield (seed or bud weight) or cannabinoid content (CBD or THC) at time of harvest. Corn earworm is the major pest of hemp produced outdoors and studies occurred to evaluate monitoring and management strategies. Pheromone traps may be valuable in determining when corn earworm moths are present in the vicinity of hemp fields but are not useful in predicting larval presence in buds or final crop damage. Larval presence and final crop damage are related. Brown marmorated stink bug does not appear to be a concern in hemp, at least at this time.

The Virginia Integrated Pest Management Expert for Wheat was designed to combine the best available information regarding wheat pest management of disease pathogens, weeds, and insects into a decision support system that would provide potential outbreak risk and pest control information to the Comprehensive Resource Planning System (CROPS). In addition, the system stands alone as an educational tool for farmers and Extension personnel.

This is a rule-based system developed on the Microsoft Windows platform. Knowledge about crops and pest management is represented in the form of IF/THEN rules, demons, and "when-changed" methods. The inference engine analyzes specific crop system information entered by the user to determine potential risks of outbreak for wheat crop pests common to Virginia. These potential outbreak risks are presented as low, medium, and high levels of risk and are presented for each of 15 pests of wheat in Virginia.

The system was evaluated using thirty random cropping system scenarios. By comparing expert system output with output from human experts, it was shown that the expert system agreed with human expert opinions in 84 percent of the decisions made. Statistical analysis of the insect pest data showed that there was no significant statistical difference between the distribution of the human expert predictions and the expert system predictions. Statistical analysis of the disease pest data showed that there were some significant statistical differences between the distribution of the human expert predictions and the expert system predictions.
Master of Science

Pests can impact significantly upon the economy, the environment and on human and animal health. However, for pest birds there are surprisingly few studies of these impacts and how to reduce them. The aim of this thesis is to advance our understanding of the ecology, impacts, and management of pest birds using case studies for each of the three main impacts. In considering economic impacts I estimate pest bird abundance, describe a novel method for measuring bird damage, and evaluate the efficacy of lethal and non-lethal methods in vineyards and orchards. Using data across 185 property years, netting was found to be the most effective in reducing bird damage. Shooting was not as effective but was one-third of the cost and had 13% lower damage compared with nil-treatments. Scaring with electronic devices and visual deterrents had no effect on bird damage. Despite their widespread use, lethal methods had limited effectiveness for reducing pest abundance. In considering environmental impacts introduced mallards on Lord Howe Island were used as a case study. Phenotypic characteristics suggest that mallards have supplanted the native Pacific black duck on Lord Howe Island. Management alternatives are evaluated and discussed. In considering health-related impacts wild birds and avian influenza in Australia was used as a case study. Here, the ecology of Australia’s Anseriformes, and the epidemiology, modes of transmission, and the factors influencing the prevalence of avian influenza in Australia’s wild birds are investigated. Risk profiles to improve the efficiency and relevance of wild-bird surveillance are also provided. The case studies presented demonstrate that an understanding of a pest’s ecology, efficient measures of impacts, and thorough evaluations of surveillance and management strategies are essential for effectively managing their economic, environmental and health-related impacts.

Integrated pest management (IPM) is a multi-layered approach to reducing pest pressure, primarily in agriculture, but also in national parks and urban settings. Its purpose is to maintain acceptable levels of productivity whilst avoiding the adverse effects associated with indiscriminate chemical control, such as pesticide resistance, secondary infestation, resurgence and harm to human health and the environment. It is a complex system, science-driven and information-based, and there are a wide range of actors involved in its development and implementation. These actors occupy various social locations. They are grouped in institutions for research and extension, in industry and related associations, in funding bodies, policy-making departments, and agricultural communities. IPM requires concerted effort from all involved; yet in some cases, social inequality characterises relations between the groups. Consequently, different groups address different layers of the IPM whole. Some groups have greater societal power to promote their developmental activities than others do, and when these differing activities meet in practice, as they must, conflict and contradiction can arise. This thesis attempts to understand the social construction of IPM by examining the process of IPM development and implementation. It follows the Science and Technology Studies (STS, also termed Science, Technology and Society) theoretical framework of the interrelationship, rather than separateness, of science, technology and society. It examines the way social relations influence technological developments in IPM, and the way IPM technologies influence social relations.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Faculty of Science and Technology
Science, Environment, Engineering and Technology
Full Text

The purpose of this study was to assess the adoption response of cotton growers to Integrated Pest Management (IPM) programs, identify the extension strategies used to promote IPM, and provide descriptive comparison of IPM programs between the foremost eleven cotton-producing states in the United States. Integrated pest management is presented as an alternative agricultural production strategy referred to as sustainable agriculture. IPM programs for cotton were evaluated by use of a survey instrument and telephone interviews with the IPM coordinators for the eleven cotton-producing states. The most significant findings were that programs vary considerably between states; the most widely employed IPM techniques were selective use of chemicals, use of economic thresholds and sampling for pests; the Cooperative Extension Service worked closely with private consultants and grower associations; and adoption of a wide variety of IPM techniques has been extensive for cotton producers in the eleven foremost cotton-producing states.

Integrated pest management (IPM) has gained recognition worldwide as a key tool for sustainable arable farming. Promoting natural pest control, strategic use of insecticides, and farmer participation are three important elements in IPM. However, knowledge gaps exist related to the economic value of natural pest control service, insecticides’ efficacies and side effects, and farmers’ incentives to adopt natural pest control in arable fields. This thesis addresses these gaps using UK and European arable crop systems. With a natural enemy exclusion experiment and economic surplus method, the annual economic value of predators and parasitoids for the summer grain aphid (Sitobion avenae) control in wheat (Triticum spp.) in South East England was estimated to be £0-2.3 Million, depending on the aphid infestation levels. Insecticidal sprays based on action thresholds would enhance the value of this ecosystem service. By conducting a UK online survey among experts on insecticide efficacies and side effects in oilseed rape (Brassica napus) protection, relatively older chemical groups were perceived to have lower efficacies for target arthropod pests than newer ones. Foliar sprays were perceived to have greater negative impacts than seed treatments on users’ health, natural enemies, pollinators, soil and water. Many foliar active ingredients pose potential risks for non-target arthropod species in UK oilseed rape fields. Through an interview of European arable farmers participating in an agri-environmental project, respondents’ willingness to encourage natural (animal) pest control was relatively low. In comparison, using insecticides to control pests was the typical practice. Ordinal logistic regression indicated that farmers’ decision to promote natural pest control was positively associated with the perceived importance of this ecosystem service on crop production, but negatively associated with the perceived number of important pests in the fields. The implications of these findings and avenues for future research to enhance IPM in arable crops are discussed.

This research was conducted to assess the intersection of gender and pesticide knowledge to identify gendered dynamics that may prove important to consider when implementing an Integrated Pest Management (IPM) program. Key findings include knowledge being associated with task undertaken, not necessarily the gender of a person. Often, due to social conceptions of appropriate gender roles, similar knowledge may be associated with a certain gender because they are engaging in similar tasks, but it is not their sex or gender that inherently gives them such knowledge. Therefore, knowledge generally associated with women can be associated with men if they are engaging in similar work. Additionally, triangulation of data through using various research methodologies, and interdisciplinary research are imperative for developing comprehensive research or development programs. Finally, even people who are concerned with the negative human and environmental health effects of pesticides may not be using them in a cautious manner. Outside factors such as market sale, education and income level must be taken into account when assessing why pesticides are used and the best methods to introduce an alternative pest control method, such as IPM.
Master of Public and International Affairs

12 pp.
This document is intended to help you develop an implementable IPM Plan for your school or school district. We have provided a modifiable template which can be downloaded at: http://cals.arizona.edu/apmc/westernschoolIPM.html#pubs.

31 pp.
Many pests encountered in homes and structures can be prevented by using simple techniques collectively known as “pest-proofing”. If done correctly, pest-proofing your home saves you money by reducing pest management costs, and more importantly, reduces potential pesticide exposure. This publication describes general indoor and outdoor pest-proofing measures and some of the major pests encountered in and around homes and structures.

La demanda mundial d’aliments ha dut al desenvolupament d’una intensa activitat agrícola produint la fragmentació, modificació i simplificació dels hàbitats naturals ja documentats com una de les principals causes de l’extinció i pèrdua de la diversitat d’espècies. La biodiversitat que tenen els ecosistemes proveeix d’una sèrie de serveis ecosistèmics a l’ésser humà i el control biològic natural de plagues es un dels serveis que s’ha vist alterat especialment als agroecosistemes. Tot i que existeix una creixent literatura científica que suggereix que la presència d’hàbitats naturals beneficia als enemics naturals als groecosistemes, l’eficiència del control biològic segueix sent un dels principals reptes en aquests estudis, oncs els efectes varien molt entre espècies i entre estudis. Entendre els patrons d’abundància i moviment de les espècies d’enemics naturals i d’herbívors, així com les interaccions entre aquests en els paisatges agrícoles, es espacialment i temporal complex. Si bé la gestió dels hàbitats agrícoles ofereix solucions per a reduir la pèrdua del rendiment degut a les plagues, en el cas dels virus, la simplificació excessiva de la diversitat dels cultius, els sistemes intensius de cultiu i l’ús de productes fitosanitaris interfereixen amb les funcions ecològiques dels agroecosistemes alterant la epidemiologia de malalties a les plantes. Amb l’objectiu d’oferir una perspectiva general sobre la’influència que el paisatge agrícola pot tenir sobre el control biològic i la epidemiologia viral, aquesta tesis s’ha enfocat en analitzar els efectes del paisatge agrícola des d’una perspectiva de composició espacial i del maneig del camp sobre espècies d’insectes herbívors i depredadors, així com en els principals virus que afecten al cultiu del panís a la zona de la Vall de l’Ebre. La primera part de la tesis està orientada a (1) l’ampliació en el coneixement de quins són els tipus d’estudis que s’estan duent a terme per analitzar els efectes de l’agroecosistema en el control biològic, les diferents metodologies i els resultats més recents (Capítol 1), i (2) els diferents efectes que té l’estructura (composició i configuració) del paisatge i les variables locals en les espècies de depredadors i herbívors presents en el cultiu de panís (Capítol 2). La segona part de la Tesi està orientada a estudiar els efectes del paisatge sobre tres dels principals virus que afecten al cultiu de panís (1) dos virus generalistes de vector: el virus del mosaic de la canya de sucre (SCMV) i el virus del mosaic nanitzant del panís (MDMV) (Capítol 3), i un virus especialista de vector: el virus del nanisme rugós del panís (MRDV) (Capítol 4). Les principals conclusions d’aquesta tesis doctoral són: (1) els estudis de caràcter funcional on s’estudia composició del paisatge han demostrat que les espècies d’enemics naturals necessiten hàbitats specífics, però que altres variables com són els efectes locals del cultiu també poden afectar a les seves dinàmiques i les de les plagues amb més força; (2) la superfície de fruiters afecta negativament als depredadors potencials del panís, però que les cobertes vegetals d’aquests afecten positivament a certes espècies d’herbívors en absència del panís; (3) l’alfals actua com un cultiu que aporta depredadors i herbívors al cultiu de panís actuant com un recurs per a les espècies més importants dels hàbitats seminaturals; (4) la incidència viral al panís està influïda principalment per la data de sembra i per la cobertura i presència d’espècies de gramínies als marges. Aquests resultats obren una via en el coneixement dels efectes que produeixen tant la composició del paisatge agrícola com el maneig del propi camp en l’abundància i distribució d’herbívors, depredadors i de virus en el cultiu de panís. Aquests resultats a més suggereixen que s’han de contemplar mesures de gestió a escala local que garanteixin nivells mínims de biodiversitat i sostenibilitat com a base inicial per al desenvolupament de programes més eficients de control biològic de plagues i virus.
La demanda mundial de alimentos ha llevado al desarrollo de una intensa actividad agrícola produciendo una fragmentación, modificación y simplificación de los hábitats naturales ya documentada como una de las principales causas de la extinción y pérdida de la diversidad de especies. La cantidad, estructura y forma de la superficie de estos hábitats naturales fragmentados genera efectos positivos o negativos sobre la abundancia y diversidad de las especies. La biodiversidad que tienen los ecosistemas provee de una serie de servicios ecosistémicos al ser humano, y el control biológico natural de plagas es uno de los servicios que se ha visto alterado especialmente en los agroecosistemas. Aunque existe una creciente literatura científica que sugiere que la presencia de hábitats naturales beneficia a los enemigos naturales en los agroecosistemas, la eficiencia del control biológico sigue siendo uno de los principales retos en estos estudios, pues los efectos varían mucho entre especies y entre estudios. Entender los patrones de abundancia y movimiento de las especies de enemigos naturales y de herbívoros en los paisajes agrícolas, así como las interacciones entre estos, es espacial y temporalmente complejo. Si bien la gestión de los hábitats agrícolas ofrece soluciones para reducir la pérdida de rendimiento debido a las plagas, en el caso de los virus la simplificación excesiva de la diversidad de los cultivos, los sistemas intensivos de cultivo y el uso de productos fitosanitarios interfieren con las funciones ecológicas de los agroecosistemas alterando la epidemiología de enfermedades en las plantas. Con el objetivo de ofrecer una perspectiva general sobre la influencia que el paisaje agrícola puede tener sobre el control biológico y la epidemiología viral, esta tesis se ha centrado en analizar los efectos del paisaje agrícola desde una perspectiva de composición espacial y del manejo del campo sobre especies de insectos herbívoros y depredadores, así como en los principales virus que afectan al cultivo de maíz en la zona del Valle del Ebro. La primera parte de la tesis está orientada a (1) la ampliación en el conocimiento de cuáles son los tipos de estudios que se están realizando para analizar los efectos del agroecosistema en control biológico, las diferentes metodologías y los resultados más recientes (Capítulo 1), y (2) los efectos que tiene la estructura (composición y configuración) del paisaje y las variables locales en las especies de depredadores y herbívoros presentes en el cultivo del maíz (Capítulo 2). La segunda parte de la tesis está orientada a estudiar los efectos del paisaje sobre tres de los principales virus que afectan al cultivo del maíz (1) dos virus generalistas de vector: el virus del mosaico de la caña de azúcar (SCMV) y el virus del mosaico enanizante del maíz (MDMV) (Capítulo 3), y un virus especialista de vector: el virus del enanismo rugoso del maíz (MRDV) (Capítulo 4). Las principales conclusiones de esta tesis son: (1) los estudios de carácter funcional donde se analiza la composición del paisaje han demostrado que las especies de enemigos naturales necesitan de hábitats específicos, pero que otras variables como son los efectos locales del cultivo también pueden afectar a las dinámicas de los enemigos naturales y los herbívoros con más fuerza; (2) la superficie de frutales afecta negativamente a los depredadores potenciales en el maíz, pero que las cubiertas vegetales de estos afectan positivamente a ciertas especies de herbívoros; (3) la alfalfa actúa como un cultivo que aporta depredadores y herbívoros al cultivo del maíz actuando como un recurso para las especies con mayores efectos que los hábitats semi-naturales; (4) la incidencia viral en el maíz está influenciada principalmente por la fecha de siembra y por la cobertura y presencia de especies de gramíneas en los márgenes. Estos resultados abren una vía en el conocimiento de los efectos que produce tanto la composición del paisaje agrícola como el manejo del propio campo en la abundancia y distribución de herbívoros, depredadores y de virus en el cultivo del maíz. Además, son una base para predecir las consecuencias de la modificación de las prácticas agrícolas en el control biológico de plagas y de virus en el cultivo del maíz. Estos resultados además sugieren que deben de contemplarse medidas de gestión a escala local que garanticen niveles mínimos de biodiversidad y sostenibilidad como base inicial para el desarrollo de programas más eficientes de control biológico de plagas y virus.
The global demand for food has led to the development of intense agricultural activity resulting in fragmentation, modification and simplification of natural habitats already documented as one of the main causes of extinction and loss of species diversity. The quantity, structure and surface shape of these fragmented natural habitats generate positive or negative effects on the abundance and diversity of species. The biodiversity that ecosystems have provides a series of ecosystem services to humans, and natural biological control is one of the services that has been altered, especially in agroecosystems. Although there is growing scientific literature that suggests that the presence of natural habitats benefits natural enemies in agroecosystems, the efficiency of biological control remains one of the main challenges in these studies, as the effects vary greatly between species and between studies. Understanding the patterns of abundance and movement of natural enemies and herbivores, as well as understanding the interactions between them, is spatially and temporarily complex in agricultural landscapes. While agricultural habitat management offers solutions to reduce yield loss due to pests, in the case of viruses, the excessive simplification of crop diversity, intensive cropping systems and the use of phytosanitary products interfere with the ecological functions of agroecosystems, altering the epidemiology of diseases in plants. With the aim of offering a general perspective on the influence that the agricultural landscape can have on biological control and viral epidemiology, this thesis has focused on analysing the effects of the agricultural landscape from a spatial composition and field management perspective on species of herbivorous and predatory insects, as well as in the main viruses that affect the cultivation of maize in the area of the Ebro Valley. The first part of the thesis is aimed at (1) broadening the knowledge of identifying the types of studies that are being conducted to analyse the effects of agroecosystem on biological control, the different methodologies and the most recent results (Chapter 1), and (2) the effects of the structure (composition and configuration) of the landscape and the local variables in the predators and herbivores present in the cultivation of maize (Chapter 2). The second part of the thesis is aimed at studying the effects of the landscape on three of the main viruses that affect the cultivation of maize (1) two generalist vector viruses: the sugarcane mosaic virus (SCMV) and the maize dwarf mosaic virus (MDMV) (Chapter 3), and a vector specialist virus: the maize rough dwarf virus (MRDV) (Chapter 4). The main conclusions of this thesis are as follows: (1) functional studies where landscape composition is studied have shown that natural enemy species need specific habitats, while other variables such as the local effects of the crop can also affect the dynamics of natural enemies and herbivores with greater weight; (2) the surface of orchards negatively affects potential predators in maize, but the plant cover of these positively affects certain species of herbivores; (3) alfalfa acts as a crop that contributes predators and herbivores to the cultivation of maize acting as a resource for species with higher effects than semi-natural habitats; and (4) the viral incidence in maize is mainly influenced by the planting date and the cover and presence of grass species at the edges. These results offer additional knowledge about the effects produced by both the composition of the agricultural landscape and the management of the field itself in the abundance and distribution of herbivores, predators and viruses in the cultivation of maize. In addition, they provide a basis for predicting the consequences of the modification of agricultural practices in the biological control of pests and viruses in the cultivation of maize. These results also suggest that local management measures that guarantee minimum levels of biodiversity and sustainability should be considered as the initial basis for the development of more efficient biological control programmes for pests and viruses.

The essay covers the subject of pest management in the developing world with focus on Africa. A small study was conducted in the Babati district in Tanzania. The division of labour is usually quite gender specific. Men have the main responsibility for cash crops while women often are responsible for the families food crops as well as household work and taking care of the children. Pest management often also falls on their lot. Yet women get very little information and education as well as gain access to important resources that could lighten their work load. Farmers generally use chemical pesticides as their main method. In the larger cash crops fields especially, farmers feel that it is too difficult to use other methods with exception for crop rotation and in some cases intercropping. In the smaller plots for family use it was however more common that other methods were used. However chemical pesticides were still used if they could be afforded. Tasks being so gender specific women have different needs than men but they are rarely asked what they need and how they perceive things. There seems to be a lot of bias and great misconceptions when it comes to the importance of women in agriculture.

Canada thistle is a clone forming perennial weed that spreads aggressively and is difficult to control. One approach to managing invasive weeds is integrating numerous tactics instead of relying on a single tactic. Therefore, the objectives of this research were: 1) assess impacts of Hadroplontus litura, common sunflower competition, and soil nutrients on Canada thistle, and 2) investigate head capsule morphometrics and model H. litura developmental timing. Common sunflower competition, low soil nutrients, and H. litura herbivory negatively impacted aspects of Canada thistle growth and reproduction, but effects varied. Additionally, H. litura effects on thistle morphology were mild whereas the effects of soil nutrition and competition were persistent throughout the experiment. Histogram analysis and verification via Dyar?s rule produced adequate larvae categorization by instar number. Logistic thermal time models developed to predict mean developmental time were most accurate for first instar larvae and least accurate for egg stage.

The bluegrass billbug (Sphenophorus parvulus Gyllenhal) and hunting billbug (Sphenophorus venatus vestitus Chittenden) have become important pests of orchardgrass (Dactylis glomerata L.) grown in Virginia, causing 40 - 100% stand losses according to a 2005 survey of over 324 ha (800 ac) of orchardgrass. Their sheltered feeding habits combined with a lack of labeled insecticides for orchardgrass make billbug control extremely difficult for this crop. Over two seasons, orchardgrass fields were surveyed for paired feeding holes caused by feeding of the billbug spring adult. Simultaneously, barrier pitfall traps, a standard method for determining the presence of billbugs in orchardgrass, were used to trap billbug adults in the fields. A comparison of these methods using a Wilcoxon sign-ranked test found no significant differences in the time when paired feeding holes were first observed in fields and when billbug adults were first trapped, showing that the methods are equally satisfactory for determining the presence of billbugs in orchardgrass. In addition, temperature data from SkyBit E-Weather® service, which are currently used to alert growers and other interested parties of pertinent billbug activity in orchardgrass, was compared to data from a field-based weather data logger over the two seasons. A comparison of these data showed high coefficients of correlation, indicating a close relationship between these two degree-day collection methods. Therefore, the SkyBit system can continue to be used for the alert system. A field-border application of Metarhizium anisopliae (Metschnikoff) Sorokin strain F52 (Met-52), an entomopathogenic fungus, was evaluated against billbug adults as they enter orchardgrass fields in the spring. Randomized pairs of treated and untreated plots were placed along the edge of an orchardgrass field in studies over two seasons. Plots were monitored for billbug adults using barrier pitfall traps, and billbug adults were checked for Met-52 infection. The Met-52 proved unsatisfactory for controlling billbugs in this study. A field efficacy trial was used to evaluate several insecticides and Met-52 against billbug adults in orchardgrass over two seasons. A randomized complete block design, four insecticide treatments and an untreated control were used in each of two trials. Samples from each treatment plot were dissected and checked for billbug life stages and for injury to orchardgrass plants. In one trial, plants in the Sevin XLR Plus® treatment were found to have a significantly higher percentage of injury to the crowns than all other treatments except Mustang Max. No other significant differences were seen in this study.
Master of Science in Life Sciences

Genetic transformation techniques for pest insects have enabled the development of novel methods to mitigate the enormous harm done by insects to human health (through transmission of diseases) and to agriculture (through damage to crops or livestock). I use mathematical modelling to analyse strategies using autocidal genetic constructs (dominant lethal genes that are repressible during mass-rearing); in parallel several research groups are developing the strains and the laboratory and field experimental work. Engineered insects would be released in large numbers and compete for mates, and their progeny would inherit one copy of a dominant lethal gene and die. The lethal mechanism can be made stage- or sex-specific. The aim is to reduce the number of pest insects in a population, suppressing numbers to a less harmful level or local elimination. I examine the evolutionary, ecological, and economic cost and benefit aspects of these novel interventions. I consider application of this genetic technology against agricultural pest insects, combined with genetically modified crop plants engineered to produce insecticidal toxins, to which field-evolved resistance is emerging. Using a theoretical framework, I analyse the gene frequency evolution of resistant alleles and show that strategies using genetic constructs that are selectively lethal only to females could help to manage both pests and resistance. I investigate potential resistance to the lethal mechanism of the genetic construct itself. I use population genetics and population dynamics models to explore the impact of heritable biochemically-based resistance on the effectiveness of genetic strategies for reducing populations of important pests in agriculture or public health. Released insects are homozygous for susceptibility to the lethal construct; this has an inherent element of resistance dilution. Finally, I analyse genetic vector control methods to reduce the transmission of human disease. I combine vector population dynamics and epidemiological models with techniques for assessing cost-effectiveness of a genetic strategy for controlling a vector mosquito, and show that disease elimination is feasible on a practical timescale and economically beneficial.

Thesis (M.S.)--West Virginia University, 2001.
Title from document title page. Document formatted into pages; contains vii, 48 p. Vita. Includes abstract. Includes bibliographical references (p. 33-34).

Five foliar insecticide treatments (Esteem, two rates of Provado, two rates of Applaud, Prev-am, and Danitol + Lorsban) were evaluated for their control of woolly whitefly infestations in grapefruit. All of these products demonstrated efficacy in mitigating woolly whitefly populations. Danitol + Lorsban was the best knock-down treatment evaluated, but for sustained control, Esteem appeared to be most effective. Applaud demonstrated good activity, but the rate we tested may be a little low; the 1.0 lb/ac rate should be evaluated. Provado at 19 oz/ac was a good treatment, while the 10 oz/ac rate appears to be sub-par. Prev-am is a oil based contact material and demonstrated good initial activity. Soil injections of 16 and 32 oz/ac of Admire were very effective against WWF, and there were no detectable differences between the two rates. Previous experiments with soil injections of Admire in citrus suggested that as much as six weeks needs to pass before the trees have enough time to adequately take up the Admire from the soil. However, these data suggest that smaller trees, about 10 ft tall, may require as little as two weeks to pick up the material.

Growers, Pest Control Advisors and Cooperative Extension, University of Arizona personnel coordinated areawide pest management activities in an area near Gila Bend, AZ to maximize the effectiveness of strategies to control pink bollworm and whitefly. Data on insect populations and pesticide applications is held within a database that is shared with cooperators on a real time basis. Control measures are discussed and common goals reached for reduction of pests within the area. Assessments from growers support the whitefly survey activities of the personnel. Fields were surveyed once per week. Data describing the population is faxed or phoned to the Pest Control Advisor and remedial action implemented at their discretion. Cooperative Extension personnel suggested pesticide use patterns to reduce resistance of whitefly and checked for field populations using University of Arizona recommendations. In 1995 an areawide pin head square program was followed based on Heat Units After Planting for timing pink bollworm susceptible stage of the cotton plant for each field and combined with the Heat Unit Model for pink bollworm emergence to determine percent emergence of the population. In 1996, many of the growers planted genetically engineered cotton and used lures to reduce pink bollworm and used the insect growth regulators under the Section 18 for whitefly control.

Eight foliar insecticide treatment regimes (single applications of Esteem, Danitol + Lorsban, Applaud, Provado and Prev-am, and two applications of Applaud, Provado, and Prev-Am) were evaluated for management of woolly whitefly infestations in grapefruit. All of these products demonstrated efficacy in mitigating woolly whitefly populations. Danitol + Lorsban appeared to be the best knock-down treatment evaluated, but Provado and Prev-Am also demonstrated good activity. For sustained control, all of the treatments were effective; however, Prev-Am required an additional application to achieve equivalent control. Soil injections of 16 and 32 fl-oz/ac of Admire were very effective against WWF, and there were no detectable differences between the two rates. The Admire appeared to require about 27 days after injection to demonstrate consistent activity.

Doutoramento em Engenharia Agronómica - Instituto Superior de Agronomia - UL
Consumer awareness of health and environmental safety has led to the design and application of policy tools for the dissemination of sustainable agricultural practices, such as integrated pest management, and of rules for the proper use of pesticides. In the last two decades, the adoption of integrated pest management has increased in Europe and, since 2014, farmers should use it as a basis for their crop protection strategy, according to the Sustainable Use of Pesticides Directive. Within this framework, this thesis involves an assessment of the technical and environmental benefits that are a result of integrated pest management adoption, an analysis of the demand for food products obtained in this farming system, which is differentiated though the presence of attributes related to health safety and environmental quality, and a discussion of the policy tools that might be used to promote the reduction or nonuse of pesticides. Integrated pest management evolution in Portugal is described based on country statistics. At the same time, farming practices and farmers’ attitudes, perceptions and motivations, as well as pesticide monitoring and biodiversity assessment, were collected in vineyards and apple and pear orchards. A set of sustainable farming practices and attitudes associated with integrated pest management adoption was identified as possible environmental indicators that can be useful to measure the associated benefits. Pesticide use, biodiversity, farmers’ attitudes and perceptions (or motivations) and technical itineraries were included in a global indicator - the Pesticide print – that can be used to assess the environmental impact caused by the crop protection strategy and pesticide use. Integrated pest management farms presented a lower impact on the environment, when compared with conventional farms (about 5% less). The Pesticide print proved to be a good global indicator that can be used to assess the impact of different farming systems, per country, region, farmers’ association, over time, as well as to define a framework of technical commitments that should be adopted to obtain effective benefits from the sustainable use of pesticides. We have also tried to understand the Portuguese consumers’ attitudes and knowledge about the sustainable use of pesticide and its effects on the purchasing frequency of certified food products produced in environmentally friendly and healthy farming systems, such as integrated pest management. Our sample of Portuguese consumers can be clustered in three groups - ‘habitual buyers’, ‘occasional buyers’ and ‘non-buyers’ - based on their experience in buying certified food and knowledge about the use of pesticides in agriculture and its risks for human health and the environment. The lack of consumer knowledge and awareness concerning pesticide use stands as a key issue for policy design and marketing strategies. Finally, we developed an innovative method that uses data from stated preference methods (discrete-choice contingent valuation data) in a much more straightforward way to estimate the probability of purchasing differentiated products as a function of the price premium level, household income, level of consumption of the food item, and knowledge about environmentally friendly and healthy farming systems. This approach allowed us to define a demand curve for food from farming systems that use less, or don’t use, pesticides (sustainable use of pesticides), when conventional food is also available, and to compare the option for “market differentiation” with alternative policy tools to promote the sustainable use of pesticides.

In the management of agricultural insect pests, short-term costs must be balanced against long-term benefits. Controls should be selected to account for both their immediate and downstream effects upon the demography and genetics of the pest, enabling suppression today without threatening suppression tomorrow. The iterative, algorithmic method of dynamic programming can provide optimal solutions to problems of this type, in which actions are taken sequentially and each action may influence those which follow it. However, this approach is fundamentally constrained with regards to the magnitude of the problems it may solve. As questions of insect pest management can be subject to ecological and evolutionary complexities, this may place them beyond the scope of dynamic programming. When it is the intricacies of a problem that are of interest, it may be more productive to utilise approximate dynamic programming (ADP) methods which can attempt problems of arbitrary complexity, although at the expense of no longer guaranteeing optimality. In this thesis I first challenge a dynamic programming algorithm with the management of a hypothetical insect pest feeding upon a transgenic insecticidal crop. The model explores how different realisations of fitness costs to resistance influence the algorithms suggested actions. I then apply a brute-force variant of ADP, a lookahead policy, to the management of a stage-structured, continuously reproducing pest population. This was to explore the extent to which an algorithm with a limited temporal perspective is able to balance the timetable of pest demography against the timescale over which insecticidal sprays and bisex-lethal sterile insect releases unfold. This same decision framework is then applied to a modified problem in which resistance to insecticidal toxins may evolve and releases are now male-selecting. This was used to assess the efficacy with which simple lookahead policies utilise a control with delayed benefits (the male-selecting releases) and possible constraints on their capacity to respond to resistance evolution. Dynamic programming and ADP methods offer a versatile toolbox for accounting for the potential impacts of the evolutionary and ecological peculiarities of particular pests upon control decisions.

During the last decades pest management in sweet pepper has shown noticeable development through the replacement of chemical control by biological control. The augmentative release of the predatory bug Orius laevigatus and the phytoseiid predatory mite Amblyseius swirskii satisfactory manage major pests invading sweet pepper, thrips and whiteflies. In order to enhance even more this biological control program and surmounted aphids problem, recent success was attributed to zoophytophagous mirid predators. The use of mirid predators is rare in sweet pepper greenhouses, however thesis results showed that mirid can enhance pest management in sweet pepper by the exploitation of zoophytophagy. The ability of mirids and O. laevigatus to predate open sweet pepper key pest and to induce plant defence was the most important found result in this thesis. A possible augmentative release of predatory mirids with A. swirskii is the new strategy that we propose to sustain sweet pepper pest management.
Durante las últimas décadas, el control de plagas en el pimiento ha mostrado un desarrollo notable a través el reemplazo del control químico por control biológico. La liberación aumentativa del chinche depredadora Orius laevigatus y el ácaro depredador Amblyseius swirskii manejan satisfactoriamente las principales plagas, trips y mosca blanca. Con el fin de mejorar aún más este programa y superar el problema de los áfidos, se atribuyó el éxito reciente a los depredadores miridos zoofitofagos. El uso de miridos es raro en los invernaderos de pimiento, sin embargo, los resultados de la tesis mostraron que mediante la explotación de la zoofitáfia se puede mejorar el manejo de trips, mosca blanca y áfidos. La capacidad de los miridos y de O. laevigatus de preceder a la plaga clave del pimiento e inducir la defensa de la planta fue el resultado más importante encontrado en esta tesis. Una posible liberación aumentativa de los mirídos con A. swirskii es la nueva estrategia que proponemos para mantener el control de plagas del pimiento.