<p>  </p> <p>Since the commercialization of dicamba-resistant soybean and cotton, numerous instances of suspected off-target dicamba movement onto sensitive plant species have been reported. Further investigation into chemical and environmental factors that influence dicamba volatilization is warranted to better understand the mechanisms that lead to increased dicamba off-target movement via volatilization and plant response to dicamba vapor. The environmental impacts of dicamba must be minimized in order to ensure the sustainability and continued use of dicamba, which is an important herbicide for controlling broadleaf weeds in key cropping systems and non-crop sites. </p> <p>Controlled environment experiments were conducted to characterize the chemical interactions with dicamba volatility for three formulations of dicamba on glass slides. Dicamba volatility was similar for spray solution pH levels 4 to 8 for the diglycolamine (DGA) and the diglycolamine with VaporGrip® (DGA+VG) formulations. For the N,N-Bis-(3- aminpropyl) methylamine (BAPMA) formulation, dicamba volatility increased at a pH level of 5 with continued increases in volatility occurring as spray solution continued to decrease indicating that BAPMA formulation is more sensitive to pH fluctuations than the DGA and the DGA+VG formulations. While spray solution pH levels below 4 increased dicamba volatility for all three formulations compared to each formulation applied at a native pH level (5.53, 5.2, and 6.28 for the DGA, DGA+VG, and BAPMA formulations, respectively), the largest increase in dicamba volatility occurred when ammonium or iron was added to spray solution. Therefore, applicators should avoid mixing dicamba with other tank-mix partners that contain ammonium or iron to minimize the likelihood for dicamba volatilization. </p> <p>While extensive research exists documenting the process of dicamba volatilization, there has been little confirmation regarding how volatilized dicamba enters sensitive plants. Dicamba-sensitive (DS) soybean with different levels of canopy conductance, from different watering regimes and exposure time of day, were exposed to dicamba vapor. The DS soybean response was positively correlated with soybean canopy conductance during the dicamba vapor exposure suggesting that dicamba vapor route of entry into soybean is facilitated through the stomata. An additional experiment was conducted that exposed the single side of a hypostomatic leaf to dicamba vapor on different northern red oak trees. Northern red oak tree response was substantially greater when the abaxial leaf surface (high stomatal density) was exposed to dicamba vapor compared to when the adaxial leaf surface (no stomata) was exposed to dicamba vapor. Thus, dicamba vapor entry into plants is largely facilitated via stomata and secondly through re-deposition onto the leaf surface, where dicamba is absorbed through the plant cuticle, albeit minor. If dicamba vapor is redeposited onto leaf surfaces, dicamba acid absorption through the cuticle can be limited without the presence of a surfactant. Field and greenhouse experiments confirmed that the presence of surfactants from applications of other formulated herbicides can exacerbate soybean response to dicamba acid that was deposited on the leaf surface. </p> <p>In the midwestern United States, off-target dicamba movement to DS soybean has been problematic as DS soybean are extremely sensitive to very low concentrations of dicamba. Field and greenhouses studies confirmed that there are phenotypic differences amongst different soybean genotypes and their response to dicamba. Estimations of visual soybean injury was approximately 10% less for genotypes that were less sensitive to dicamba compared to genotypes with increased sensitivity. The future identification of the mechanisms that lead to decreased sensitivity to dicamba could be used to identify soybean cultivars that could mitigate the impacts of dicamba off-target movement to DS soybean. </p> <p>Lastly, a field experiment was conducted that investigated the influence of simulated dew on dicamba volatility from dicamba treated soybean leaves, in addition to soybean response in the presence of dicamba vapor. The results from a field experiment determined that consecutive simulated dew applications increase dicamba volatility from dicamba treated soybean. Furthermore, this is the only research demonstrating that DS-soybean response increases from dicamba vapor in the presence of dew. The results from this dissertation provide further insight into the chemical and environmental factors that influence dicamba volatility, the route of entry of dicamba vapor into plants, and soybean response to dicamba.</p>

No / This is the second in a series of three papers from a project that has attempted to answer the question ‘does the application of agrochemicals accelerate the corrosion of archaeological metals in the top 50cm of the soil?’. We have approached it through a combination of field-based experiments, by establishing laboratory microcosms and by using geochemical modelling techniques to understand the processes involved. This paper reports on two different experimental approaches in the laboratory - a microcosm designed to mimic one of the burial sites (the ‘Lab Bin’ experiments), and a simpler one to understand the reaction between metal samples and concentrated aqueous solutions of the fertilizers and laboratory reagents used (the ‘Lab Beaker’ experiments). The bins were monitored for in situ corrosion and aqueous effluent collected for13 weeks, after which they were excavated and the metal coupons examined. The Lab Beakers were monitored for in situ corrosion for seven weeks, and then the coupons examined. We focus here on a sub-set of the data relating to the behaviour of the thinnest samples of copper in each case. As with the field data previously reported, the results are sometimes contradictory, but on balance this project has demonstrated that applied agricultural chemicals are likely to accelerate the rate of corrosion of metal objects within 50cm of the surface. In particular, it is likely that any fertilizers containing KCI will be particularly aggressive.

No / This is the third in a series of papers from a pilot project that has attempted to answer the question ‘does the application of agrochemicals accelerate the corrosion of archaeological metals in the top 50cm of the soil?’. We have approached it by a combination of field-based experiments, by establishing laboratory microcosms and by using geochemical modeling techniques to understand the processes involved. This paper reports on the geochemical modelling simulations that trace the potential corrosion pathways followed in two sets of laboratory microcosm experiments (‘Lab Beakers’ and ‘Lab Bins’) and one field experiment (at Palace Leas). This approach uses soil solution as the fluid mediating corrosion in the soil vadose zone. Soil solution was displaced following controlled exposure to fertilizers. Modelling using The Geochemists Workbench was carried out to mimic the experimental conditions, and predictions were compared with image analysis results, limited XRD analysis and published corrosion observations. We focus here on a sub-set of the data relating to the behaviour of the thinnest samples of copper in each case. As with the field and laboratory data previously reported, the results are sometimes contradictory, but on balance this project has demonstrated that applied agricultural chemicals are likely to accelerate the rate of corrosion of metal objects within 50cm of the surface. In particular, it is likely that any fertilizers containing KCI (‘potash’) will be particularly aggressive. Geochemical modeling generates plausible corrosion predictions based on post-depositional interaction between archaeological copper and soil solution, and appears to be useful in helping to simplify and understand corrosion pathways in naturally complex systems.

No / Part of a project that has attempted to answer the question ‘does the application of agrochemicals accelerate the corrosion of metals in the top 50cm of the soil? ’ is reported. We have approached the question by a combination of field-based experiments (on two sites), establishing laboratory microcosms (one involving simple aqueous systems and the other a series of simulated burial experiments) and by using geochemical modelling techniques to understand the processes involved. Two different experimental approaches in the field are documented — one using in situ monitoring of corrosion potentials and the other assessing the degree of induced corrosion using image analysis on recovered samples. The first was carried out on arable land close to the University of Bradford to which we applied different fertilizer regimes. The second was established on land owned by the University of Newcastle at Palace Leas, Morpeth, Northumberland, which has a documented field management regime extending back over one hundred years. We focus here on a sub-set of the data relating to the behaviour of the thinnest samples of copper in each case. There does seem to be some evidence of an effect resulting from the applied fertilizer, but the data are sometimes contradictory. We suggest a number of improvements for future field experiments that monitor in situ corrosion in the vadose zone.

Orientador: Renata Fracácio / Resumo: O processo produtivo agrícola brasileiro está cada vez mais dependente dos agrotóxicos, tais produtos pelo uso constante e indevido atingem os corpos d'água e passam a interagir com a biota presente, podendo desencadear efeitos tóxicos agudos ou crônicos, além de atuar como interferentes endócrinos (IE). A maioria desses poluentes não apresenta na legislação vigente, limites de exposição segura, considerando-se os múltiplos usos dos recursos hídricos, destacando-se dentre eles a proteção da vida aquática. Diante do exposto, este estudo teve por objetivo verificar efeitos adversos do pesticida Chlorantraniliprole (CHLO) sobre a morfologia de gônadas e fígado de machos e fêmeas adultos de Danio rerio e o seu potencial para atuar como IE. O método consistiu na exposição de 63 machos e 36 fêmeas da espécie D. rerio por 14 e 21 dias a 0,60 μg/L de CHLO. O experimento foi realizado em regime semi-estático com troca total da solução teste a cada 48h, montados em aquários de vidro com capacidade para 2 L de solução teste, de modo a manter a proporção de 1g de peixe/L. O Controle (CC) foi apenas com água de cultivo e o Controle Acetona (CA) com 2,39 μl/L de acetona e água de cultivo seguindo-se recomendações da OECD (2000; 2010). Após os períodos experimentais os peixes foram eutanasiados em água com gelo a 4C° e destinados ao procedimento de histologia com inclusão na parafina, coloração com Hematoxilina e Eosina (HE) e análise em microscópio de luz. As análises histológicas das g... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Brazilian agricultural production process is increasingly dependent on pesticides, such products by constant misuse reach water bodies and begin to interact with this biota and can trigger acute or chronic toxic effects, besides acting as endocrine disruptors (IE). Most of these pollutants not presented in the current legislation, the safe exposure limits, considering the multiple uses of water resources, highlighting among them the protection of aquatic life. Given the above, this study aimed to verify the adverse effects of pesticide Chlorantraniliprole (CHLO) on the morphology of gonads and liver of adult male and female zebrafish and their potential to act as IE. The method consisted of exposure of 63 males and 36 females of the species D. rerio for 14 and 21 days to 0.60 μg / L CHLO. The experiment was performed in a semi-static scheme with complete exchange of the test solution every 48 hours, mounted on glass tanks with a capacity of 2 L of the test solution, so as to maintain the proportion of fish 1 g / L. The Control (CC) was only cultivation water and Control Acetone (CA) with 2.39 μL / L and cultivation of acetone water followed recommendations OECD (2000; 2010). After the experimental period the fish were euthanized in ice water to 4C ° and intended for histology procedure with inclusion in paraffin, staining with hematoxylin and eosin (HE) staining and examination by light microscopy. Histological analysis of the gonads of female control (CC) control and acetone (CA), 14 and 21 days showed normal distribution pattern and maturation, showing cells at different stages of development and ovaries in different maturation stages. For females exposed to (CHLO) to 0,60μg / L for 14 days, we observed a prevalence of oocytes with lipid and protein vitellogenesis (IV) and oocytes with complete vitellogenesis (V) ... (Complete abstract click electronic access below) / Mestre

nÃo hà / Dentre os vÃrios fatores apontados como responsÃveis pelo declÃnio das colÃnias de abelhas, os defensivos agrÃcolas do grupo quÃmico dos neonicotinÃides merecem destaque, principalmente o inseticida sistÃmico imidacloprido, que à um agonista da acetilcolina e age nos receptores nicotÃnicos de acetilcolina dos insetos, ocasionando comprometimento das funÃÃes vitais e morte. Com o presente trabalho objetivou-se determinar a toxicidade do imidacloprido por diferentes vias de exposiÃÃo para a abelha sem ferrÃo Scaptotrigona sp. nov. atravÃs da dose letal mÃdia tÃpica (DL50) e da concentraÃÃo letal mÃdia por ingestÃo (CL50). Esse estudo foi conduzido no Setor de Abelhas do Departamento de Zootecnia da Universidade Federal do Cearà e baseado no protocolo internacional da OECD. Os dados de mortalidade das abelhas foram anotados apÃs 24 e 48h da exposiÃÃo dos insetos Ãs diferentes dosagens do inseticida e submetidos à anÃlise do tipo dose resposta no programa Bioestat versÃo5.3. A DL50 tÃpica foi de 16,65 (24 horas) e 8,23 (48 horas) ng p.c /ÂL/abelha e a CL50 de ingestÃo foi 8,47 (24 horas) e 2,98 (48 horas) ng p.c /ÂL dieta. O imidacloprido demonstrou ser tÃxico para a espÃcie estudada e o mesmo à mais nocivo, quando administrado de forma oral, baseado na menor dosagem necessÃria para matar 50% da populaÃÃo testada. / Among the whole factors pointed as responsible for the loss of beeâs colonies, the crop protection products which belong to the chemical group of neonicotinoids deserve to be highlighted. Specially the systemic insecticides as imidacloprid which is an agonist acetylcholine and and acts on nicotinic acetylcholine receptors of insects, causing impairment of vital organ function and death. The currently job aimed to determinate the toxicity of imidacloprid by different exposition ways for stingless bees Scaptotrigona sp. nov. through the topical average lethal dose (DL50) and the intake average lethal concentration (CL50). It was conducted at Setor de Abelhas, Department of Animal Science at Federal University of Ceara and based on the international protocol of OECD. The mortality data was taken after 24 and 48 hours of exposition of the insects to different dosages and submitted to dose response analysis with Bioestat version 5.3. The topical DL50 in ng p.c /ÂL/bee was 16,65 (24 hours) and 8,23 (48 hours), and the intake CL50 was 8,47 (24 hours) and 2,98 (48 hours) ng p.c /ÂL of food. The imidacloprid has shown to be toxic to the researched bee specie, been more harmfull when taken by oral ways, based on its minor lethal dose needed to kill 50% of the tested population.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A cidade de Boa Vista, capital do Estado de Roraima, está localizada em uma área de vegetação do tipo Savanas, inserida em uma área de relevo suave, com uma densa rede hídrica e domínio dos Latossolos. A expansão urbana da cidade foi observada principalmente em seu setor Oeste, onde se intensificou a produção de hortaliças, através de um sistema convencional com o uso de produtos químicos. O objetivo desta pesquisa foi avaliar o risco de contaminação do solo por agroquímicos, em áreas de horticultura no Bairro Operário localizado na porção Oeste da cidade de Boa Vista RR. Para isto foram realizados levantamentos bibliográficos, trabalhos de campo e laboratório. Em campo ocorreram registros fotográficos, coleta de pontos em GPS, abertura de seis trincheiras para análise de perfis de solo e coleta de amostras, além de análise de dois perfis em barragens de tanques de peixes e dois perfis em paredes de drenagem pluvial, com a coleta de 29 amostras de solo. O Laboratório de Informática do Programa de Pós-Graduação em Geografia PPGGEO, da Universidade Federal de Roraima UFRR, foi utilizado para o processamento dos dados digitais, através dos softwares ArcGis 10.0, Spring 5.2 e PCI Geomatics, com a elaboração de mapas de localização, hipsometria, declividade e drenagem, usando Imagem de Satélite (LandSat 8) e Imagem TOPODATA (SRTM). As análises de granulometria/textura, foram realizadas no Laboratório de Sedimentologia do Núcleo de Pesquisas Energéticas NUPENERG - UFRR, a morfologia dos grãos foi efetuada no Laboratório de Áreas Degradadas UFRR. Para as análises de pH (potencial hidrogeniônico), e M.O.S (matéria orgânica do solo), as amostras foram encaminhadas para o Laboratório de Solos da EMBRAPA Amazônia Oriental de Belém PA. As análises mineralógicas ocorreram no Laboratório de Difratometria de Raios X do Departamento de Física UFRR. Os resultados das análises granulométricas/textura e de morfologia dos grãos, revelaram que os solos da área de estudo são arenosos, com predomínio da fração areia fina com morfologia angular e subangular. As análises de pH (potencial hidrogeniônico) e M.S.O (matéria orgânica do solo), mostraram que os solos são ácidos e pobres em matéria orgânica. Os mapas de hispometria e declividade confirmaram para área o domínio de relevo suave. Pelo mapa de drenagem foi possível observar que a área de hortas no Bairro Operário está próxima a uma densa rede hidrográfica. Assim tais resultados mostram a necessidade de ações que visem um melhor manejo do solo, tendo como objetivo a manutenção do equilíbrio ambiental. / The city of Boa Vista, capital of the State of Roraima, is located in an area of vegetation of the type Savannas, inserted in an area of soft relief, with a dense water supply and domain of Oxisol. The urban expansion of the city was observed mainly at your section west, where it was intensified the production of vegetables, through a conventional system with the use of chemical products. The objective of this research was to evaluate the risk of contamination of the soil for agrochemicals, in horticulture areas in the District of Operário, located in the portion west of the city. For so much, bibliographical risings, field works and laboratory were accomplished. In field, they happened photographic registrations, collection of points in GPS, opening of six trenches for analysis of soil profiles and collection of samples, besides analysis of two profiles in barrages of tanks of fish and two profiles in walls of pluvial drainage, with collection of 29 soil samples. The Laboratory of Computer Science of the Program of Pós-Graduation in Geography - PPGGEO, of the Federal University of Roraima (UFRR) it was used for the processing of the digital data, through softwares ArcGis 10.0, Spring 5.2 and PCI Geomatics, with the elaboration of location maps, hypsometry, steepness and drainage, using satellite image (LandSat 8) and image TOPODATA (SRTM). The grain size/texture analyses were accomplished at the Laboratory of Sedimentology of the Nucleus of Energy Researches (NUPENERG) of UFRR; the morphology of the grains was made at the Laboratory of Degraded Areas (UFRR). For the pH analyses (hipogenionic potencial) and M.O.S (organic matter of the soil), the samples were directed to the Laboratory of Soils of EMBRAPA Amazonian Oriental of Belém-shovel. The mineralogical analyses happened at the Laboratory of Diffratometry of Raios X of the Department of Physics of UFRR. The results of the analyses of grain size/texture and of morphology of the grains they revealed that the soils of the study area are sandy, with prevalence of the fraction it sands fine with angular and subangular morphology. The pH analyses and M.S.O. they showed that the soils are acid and poor in organic matter. The hypsometry maps and steepness confirmed for the area the domain of soft relief. For the drainage map it was possible to observe that the area of vegetable gardens of the District of Operário is close to a dense water supply. Like this, such results show the need of actions that they seek a better handling of the soil, tends as objective the maintenance of the environmental balance.

Le principal objectif de cette thèse est de contribuer au développement des produits oléo-chimiques formulant ou co-formulant d'intrants agricoles. Le point de départ de notre recherche était la « boite d'outils » développé au sein de LCA sous la direction de M. Zephirin Mouloungui depuis 1985, cette boite contient le travail qui été réaliser sur : - La chimie de glycérol par la mise en oeuvre de la réaction d'estérification du glycérol avec les acides gras pour l'obtention des mono glycérides purs en tant que co-formulants d'adjuvants phytosanitaires. - La chimie des esters de carbonate de glycérol, qui ont montré que le groupe cyclocarbonate possède des propriétés dipolaires et de constantes diélectrique élevés, d'excellents pouvoir solvant, et de pouvoir tensioactif. - La chimie d'oligomérisation du carbonate de glycérol dans l'objectif de proposer un fort candidat agrochimique en tant que adjuvants d'herbicides, agent de complexation et d'encapsulation. Cette boîte à outils originale et les savoir-faire accumulé au LCA nous a conduits à donner suite à ces travaux antérieurs tout en développant une nouvelle chimie d'oligomérisation des esters de carbonate de glycérol. Ce cadrage a été initié pour répondre aux spécifications suivantes : •Les molécules doivent être issues de ressources renouvelables •Elles doivent être biodégradables et éco-compatibles •Elles ne doivent pas être toxiques Les propriétés physico-chimiques apportées par les esters carboniques de cette boîte à outils doivent se montrer compétiteurs vis-à-vis des propriétés de ces molécules d'origine fossile qui rassemble jusqu'à 5 fonctionnalités adjuvantatrice : stabilité physique, chimique, et dispersabilité de la bouille, amélioration de la rétention d'eau, amélioration de l'étalement, réduction du lessivage et amélioration de la pénétration de barrière biologique. Le travail réaliser s'appuyer sur 3 axes de recherche : 1 - Synthèse d'esters carboniques cycliques pur Les esters de carbonate de glycérol ont été préparés selon un protocole opératoire mis au point au laboratoire. Les ECGs sont : L'acétate de carbonate de glycérol, L'heptanoate de carbonate de glycérol, Le nonanoate de carbonate de glycérol, L'undecylénate de carbonate de glycérol, L'oléate de carbonate de glycérol. 2- Synthèse des Oligomères d'esters de carbonate de glycérol (OECGs) Nous nous sommes concentrés dans cette partie sur la compréhension du mécanisme d'ouverture de cycle à 5 chaînons à partir des esters de carbonate de glycérol, pour l'obtention d'oligomères avec rétention contrôlée de CO2. Les paramètres opérationnels tels que, le type de réacteur, le type de chauffage, et l'inertage de réacteur ont été étudiés afin de déterminer le système le mieux adapté. Ces études ont permis de démontrer le mécanisme d'ouverture cationique du cycle carbonate à 5 chainons, réaction qui conduit à des oligomères avec un squelette carbonate-éther avec des groupes terminaux composés de carbonate cycliques et/ou des motifs glycériques. 3-Analyses et détermination des structures caractéristiques des oligomères L'analyse structurale des oligomères synthétisés (unités répétitives et groupements terminaux) a été réalisée par spectroscopie de masse SM-MALDI-TOF, ES et chromatographie d'exclusion stérique. Le MALDI-TOF est utile pour déterminer les unités répétitives dans les oligomères possédant une masse molaire comprise entre 400 et 1500 g.mol-1, alors que la technique de pulvérisation d'électrons (ES= Electron Spray) a été utilisée pour déterminer la structure des unités de masse molaire inférieure à 400 g.mol-1. La spectroscopie RMN a contribué à mesurer les unités de carbonates linéaires dans les oligomères. En résultats, les nouvelles méthodologies de synthèse chimique pour réaliser de nouveaux oligomères bio-sourcés et biodégradables, toute en respectant la réglementation REACH, ainsi que les résultats agronomiques obtenus font l'objet de dépôt de 3 brevets (Agronutrition/INRA/INPT). / The main objective of this research work is to contribute to the development of oleo-chemicals as a new brand of co formulating agricultural inputs. The starting point of our research was the "toolbox" developed within LCA under the direction of Mr. Zéphirin Mouloungui since 1985, this box contains the work that was carried out on: - Glycerol chemistry by the implementation of the esterification reaction of glycerol with fatty acids to obtain pure monoglycerides as additives for phytosanitary co-formulants. - Chemistry of glycerol carbonate esters, which showed that the cyclocarbonate group include dipolar properties and high dielectric constant, excellent solvent capacity, and surfactant ability. - The oligomerization of glycerol carbonate chemistry with the aim to provide a strong candidate as agrochemical herbicide adjuvant, complexing agent and encapsulation. This original box tools and know-how accumulated LCA has led us to act on these earlier works while developing a new oligomerization chemistry of glycerol carbonate esters. This framework was initiated to meet the following specifications: • The molecules must be derived from renewable resources • They must be biodegradable and eco-friendly • They must be non-toxic. The physicochemical properties contributed by the carbonate esters of this toolkit must show a competitive vis-a-vis the properties of the fossil originated co-formulants which gathers up to 5 adjuvantatrice features: physical & chemical stability, quality of dispersion , improved water retention, improved spreading, reduction of wash-off and improving the penetration of biological barrier. Our research work relies on three research axes: 1 - Synthesis of pure cyclic carbonate esters. Glycerol carbonate esters have been prepared according to an operating protocol developed in the laboratory. The ECGs are: Acetate of glycerol carbonate, glycerol carbonate heptanoate, glycerol carbonate nonanoate, glycerol carbonate undecylenate, glycerol carbonate oleate. 2- Synthesis of Oligomers of glycerol carbonate esters (OECGs) We focused in this part on understanding the 5- membered ring-opening mechanism from glycerol carbonate esters, to obtain oligomers with controlled CO2 retention. Operational parameters such as the type of reactor, the type of heating and the reactor inerting were studied to determine the most suitable system. These studies have demonstrated the insertion coordination ring opening mechanism of 5 membered carbonate, a reaction which leads to oligomers with a carbonate – ether backbone with cyclic carbonate compounds of terminal groups and / or glycerol units. 3-Analysis and structural determination of the oligomers. Structural analysis of the synthesized oligomers (repeating units and end groups) was performed by mass spectroscopy MALDI-TOF-MS, ES and size exclusion chromatography. MALDI-TOF is useful in determining the repeating units in the oligomers having a molecular weight between 400 and 1500 g mol-1, while the electron-spray technique (ES = Electron spray) was used to determine the structure of molar mass units less than 400 g· mol -1. NMR spectroscopy has contributed to measure the linear carbonates units in the oligomers. In results, the new chemical synthesis methodologies to produce new bio-based and biodegradable oligomers, all respecting REACH regulation and agronomic performance are subject to filing four patents (Agronutrition / INRA / INPT.

<p>  </p> <p>The objectives of this dissertation included comparing the whole gut bacterial profiles of insecticide resistant and susceptible <em>B. germanica</em> and determining how these profiles, as well as the structure and function of the gut microbiome, change in the presence of an antibiotic. Additional goals were to investigate how antibiotic treatment impacts the toxicity of the bait insecticides fipronil, abamectin and indoxacarb, and to determine how gut bacteria, and specifically the enzymes originating within gut bacteria, metabolize and convert ingested indoxacarb into its toxic metabolite DCJW. Findings show that pre-treatment with the antimicrobial compound kanamycin (KAN) led to reductions in resistance levels for fipronil and abamectin, but also increased basal toxicity levels in both resistant and susceptible strains tested. 16S bacterial sequence surveys revealed that resistant and susceptible cockroach strains were more similar before KAN treatment than after, with a stronger dysbiosis effect in the resistant strain. For the insecticide indoxacarb, regardless of strain, roaches treated with kanamycin-infused water in feeding bioassays were more susceptible compared to the control treatment, but in vial (surface contact) bioassays, only susceptible cockroaches experienced a significant shift in mortality. When the frass of indoxacarb-fed cockroaches was analyzed, fewer molecules of the hydrolytic metabolite DCJW were produced with the introduction of an antibiotic (KAN). This result was further corroborated by esterase activity assays of whole homogenized cockroach guts. All results considered, these findings provide novel evidence of microbe-mediated pro-insecticide activation in the cockroach gut. Overall, the results of this dissertation reveal previously unknown relationships between gut microbiota and their insect hosts. These microbiome relationships exposed important cockroach strain differences which may extend to the host population level. Furthermore, this research has connected a change in enzyme activity in the gut microbiome with indoxacarb, a very important marketplace pro-insecticide.</p>

Yes / Pesticide contamination is a global issue, affecting nearly 44% of the global farming population, and disproportionately affecting farmers and agricultural workers in developing countries. Despite this, global pesticide usage is on the rise, with the growing demand of global food production with increasing population. Different types of porous materials, such as carbon and zeolites, have been explored for the remediation of pesticides from the environment. However, there are some limitations with these materials, especially due to lack of functional groups and relatively modest surface areas. In this regard, metal-organic frameworks (MOFs) provide us with a better alternative to conventionally used porous materials due to their versatile and highly porous structure. Recently, a number of MOFs have been studied for the extraction of pesticides from the environment as well as for targeted and controlled release of agrochemicals. Different types of pesticides and conditions have been investigated, and MOFs have proved their potential in agricultural applications. In this review, the latest studies on delivery and extraction of pesticides using MOFs are systematically reviewed, along with some recent studies on greener ways of pest control through the slow release of chemical compounds from MOF composites. Finally, we present our insights into the key issues concerning the development and translational applications of using MOFs for targeted delivery and pesticide control.