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Dissertations / Theses on the topic 'Insecticide'
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1
Malima, Robert Chikoja Munyu. "Evaluation of long lasting insecticidal materials and treatment kits and control of pyrethroid insecticide resistant mosquitoes using alternative insecticides on nets." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.536834.
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Ngufor, C. A. "Combining unrelated insecticides for improved control and management of insecticide resistant African malaria vectors." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2015. http://researchonline.lshtm.ac.uk/2124338/.
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It is now generally accepted that if nothing is done and insecticide resistance in malaria vectors especially to pyrethroids eventually led to widespread failure of current vector control strategies, the progress achieved so far in reducing the burden of malaria could be reversed. Interventions and operational tactics capable of controlling insecticide resistant malaria vector populations and delaying the evolution of resistance need to be urgently identified and properly investigated. One important insecticide resistance management strategy is to expose vector populations to a combination of unrelated insecticides. In this study I investigated the potential of this combination concept to control and manage the spread of indoor resting insecticide resistant African malaria vectors. A series of field evaluations were performed in experimental huts in selected malaria endemic sites to investigate; 1.the impact of combining non-pyrethroid IRS or wall linings with pyrethroid LLINs against malaria vector populations with different levels of insecticide resistance and 2.The efficacy of LLINs treated with a pyrethroid and an alternative compound against pyrethroid resistant mosquitoes. The capacity of the combined intervention approach to delay the spread of insecticide resistance genes was investigated via genotyping studies. I demonstrate that the use of combined interventions and mixture net with unrelated insecticides is an effective way to improve the control of pyrethroid resistance malaria vectors. However, the performance of these combinations will undoubtedly depend on the levels and type of resistance encountered. Where resistance to both insecticides exists, improved control is unlikely. While the use of single interventions would likely exacerbate resistance the combinations would be less beneficial for preventing selection of insecticide resistance when resistance genes are already well established. The impact of these findings on malaria vector control and resistance management is discussed.
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Barstow, Ben. "Alfalfa Insecticide Trial, Coolidge." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/200497.
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Rethwisch, Michael D. "Spring Alfalfa Insecticide Trial." College of Agriculture, University of Arizona (Tucson, AZ), 1991. http://hdl.handle.net/10150/201373.
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Boundy, Sam. "Insecticide resistance in Drosophila." Thesis, University of Bath, 2003. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425854.
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Nigond, Jacques. "Intoxications aigues par les insecticides organophosphorés : à propos de 50 cas." Montpellier 1, 1988. http://www.theses.fr/1988MON11205.
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Visetson, Suraphon. "Insecticide resistance mechanisms in the rust-red flour beetle, Tribolium castaneum (Herbst)." Thesis, The University of Sydney, 1991. https://hdl.handle.net/2123/26395.
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Insecticide resistance mechanisms in five strains of beetles, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) were studied using in vitro and in viva methods.
In in vitro studies, the activities of three detoxification enzymes, monooxygenases, GSH S-transferases and esterase s were optimized.
Aldrin epoxidase activity and cytochrome P450 level were used to determine the activities of monooxygenases. The model substrates, 3,4-dichloronitrobenzene (DCNB) and 1—chloro -2,4-dinitrobenzene (CDNB) were used to measure GSH S-transferase activities. Five different esterase substrates, paranitrophenyl acetate (PNPA), naphthyl acetate (ANA), phenylacetate, methyl thiobutyrate (MTB) and acetylthiocholine iodide (ATCh) were used to investigate esterase activities.
The homogenizing medium for monooxygenases studies containing potassium phosphate buffer, pH 7.5, 1 mM EDTA, 20 mM mercaptoethanol and 50% (w/w) PVPP (weight of PVPP: weight of beetles) results in no detectable cytochrome P420 and microsomes were stored in liquid nitrogen upto 100 weeks without loss of cytochrome P450 levels.
With GSH S—transferases, GSH was required in the homogenizing medium for optimal enzyme activity.
With esterases, the homogenizing medium was the same as for monooxygenases except for the MTB and BTCh assays where mercaptoethanol was omitted. In all enzyme assays, whole beetle s were used except with ATCh assays where only the head and thorax were used.
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Bydlon, Frédéric. "Synthèse et mécanisme d'action des chromènes de série précocènes." Paris 5, 1995. http://www.theses.fr/1995PA05P204.
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Li, Jianhe. "Colloidal aspects of insecticide behaviour." Thesis, University of Hull, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397083.
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Brinzer, Robert Adolf. "Drosophila, metabolomics and insecticide action." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/7072/.
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The growing problem of insecticide resistance is jeopardising current pest control strategies and current insecticide development pipelines are failing to provide new alternatives quickly enough. Metabolomics offers a potential solution to the bottleneck in insecticide target discovery. As a proof of concept, metabolomics data for permethrin exposed Drosophila melanogaster was analysed and interpreted. Changes in the metabolism of amino acids, glycogen, glycolysis, energy, nitrogen, NAD+, purine, pyrimidine, lipids and carnitine were observed along with markers for acidosis, ammonia stress, oxidative stress and detoxification responses. Many of the changed metabolites and pathways had never been linked to permethrin exposure before. A model for the interaction of the observed changes in metabolites was proposed. From the metabolic pathways with the largest changes, candidate genes from tryptophan catabolism were selected to determine if the perturbed pathways had an effect on survival when exposed to permethrin. Using QPCR it was found that all genes in the entire pathway were downregulated by permethrin exposure with the exception of vermilion suggesting an active response to try and limit flux through tryptophan catabolism during permethrin exposure. Knockdown of the tryptophan catabolising genes vermilion, cinnabar and CG6950 in Drosophila using whole fly RNAi resulted in changes in susceptibility to permethrin for both topical and oral routes of exposure. Knockdown of the candidate genes also caused changes in susceptibility when the insecticides fenvalerate, DDT, chlorpyriphos and hydramethylnon were orally administered. These results show that tryptophan catabolism knockdown has an effect on surviving insecticides with a broad range in mode of action. Symptoms that occur in Drosophila during exposure to the different insecticides were also noted. To gain further understanding into the mechanisms affecting survival, tissue specific knockdown was performed revealing tissue and gender specific changes in survival when vermilion, cinnabar and CG6950 are knocked down. Metabolomics was performed on the knockdown strains to determine the efficacy of the knockdowns on tryptophan catabolism and to identify any knock-on effects. The results indicate that tryptophan metabolite induced perturbations to energy metabolism and glycosylation also occur in Drosophila along with apparent changes in the absorption of ectometabolites. As the knockdown of vermilion, cinnabar and CG6950 tended to result in reduced susceptibility to insecticides, they would make poor targets for insecticidal compounds, however, they may be the first examples of genes that are not directly involved in insecticide metabolism or cuticle synthesis that increase insecticide tolerance in Drosophila. As the first metabolomics data set showed evidence for oxidative stress during permethrin exposure, preliminary work was begun for identifying the tissue specificity and timing of oxidative stress in both Dipterans and Lepidopterans using Drosophila and Bombyx mori as models. In Drosophila oxidative stress did not begin immediately suggesting that the insecticide itself is not a cause, however, a rapid increase in oxidative stress occured over a six hour period after a day of oral exposure implicating catabolites of permethrin. Bombyx were highly susceptible to permethrin showing oxidative stress in the Malpighian tubule and silk gland when exposed. This study has shown that metabolomics is highly effective at identifying pathways which modulate survival to insecticide exposure. It has also brought insight into how insecticide induced pathology may cause death. Data has also been generated which could help characterize the putative transaminase CG6950.
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Umeda, K., J. Murrieta, and D. Stewart. "Pyrethroid Insecticide Comparison in Broccoli." College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/221602.
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Several pyrethroid insecticides were evaluated and compared for efficacy against lepidopterous insect pests in broccoli. Zeta-cypermethrin (Mustang®) was compared at two rates, tralomethrin (Scout X-tra®) formulations were compared, lambda-cyhalothrin (Karate®), and esfenvalerate (Asana®) were evaluated for efficacy against cabbage looper (Trichoplusia ni. CL). Following each of the applications, most of the treatments reduced the number of larger sized CL relative to the untreated check. The two rates of Mustang performed similarly as did the two formulations of Scout X-tra, emulsifiable concentrate versus gel.
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Anjum, Farida. "Relative toxicity of insecticides to crucifer pests and their natural enemies : interaction of insecticide and insect behaviours." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24773.
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Pesticides remain a necessary component of many agricultural systems and used judiciously they can play an important role in Integrated Pest Management (IPM) programmes. The aim of the present study was to investigate factors influencing the differential toxicity of insecticides against a cosmopolitan insect pest of crucifer crops, the diamondback moth, Plutella xylostella, and its respective hymenopteran parasitoid, Cotesia vestalis. Such knowledge can help in the effective use of insecticides with biological control agents in IPM. Three insecticides regarded as being compatible with some natural enemies (abamectin, spinosad, indoxacarb) and a compound generally regarded as harmful to natural enemies (lambda-cyhalothrin) were examined. Similar tests were also carried out with the peach potato aphid Myzus persicae and its parasitoid Aphidius colemani due to the loss of the Cotesia vestalis culture. A comparative measure of the intrinsic toxicity of fresh deposits (Day 0) of insecticides on Chinese cabbage was determined for both pest and parasitoid species. Lambda-cyhalothrin and abamectin were the most toxic compounds against both pests and their parasitoids, while indoxacarb and spinosad were less toxic. Residual bioassays were conducted using sprayed plants maintained under glasshouse conditions for 0-28 days after insecticide application. Results indicated lambda-cyhalothrin was the most persistent compound and abamectin and spinosad the least persistent. A leaf wax stripping technique was used with bioassays to compare the distribution of insecticide residues between the epicuticular wax layer and underlying leaf tissues. Wax removal significantly reduced the toxicity of all insecticides. No-choice and choice behavioural assays were conducted for both parasitoid species with leaf discs treated with LC5 and LC50 levels of insecticides. Both parasitoids tended to avoid insecticide-treated leaves, giving preference to untreated leaves or the arena. Emergence of adult parasitoids from cocoons/mummies on insecticide-treated leaves was not significantly different from untreated controls. The results are discussed in terms of the bioavailability of insecticides to phytophagous and non-phytophagous insect species.
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Mehmet, Ceylan. "Insecticide resistance as a biomarker for migration of Culex pipiens and its exposure to insecticides in Britain." Thesis, Queen Mary, University of London, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612578.
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Jenson, Lacey Jo. "Induction and Inhibition of a Neuronal Phenotype in Spodoptera Frugiperda (Sf21) Insect Cells." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/40929.
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Due to the increasing resistance demonstrated by insects to conventional insecticides, the need for compounds with novel modes of action is becoming more urgent. Also, the discovery and production of new insecticides is vital as regulations and restrictions on conventional insecticides become increasingly stringent (Casida and Quistad 1998). Research in this area requires screening of many candidate compounds which is costly and time-consuming. The goal of this research was to produce in vitro insect neurons from Sf21 insect ovarian cell lines, which could lead to new high throughput screening methods and a way to mass produce insect material for basic research. This study used a culture of Sf21 cells and a mixture of differentiation agents to produce viable neuron-like cells. In the presence of the molting hormone 20-hydroxyecdysone (20-HE), or insulin, in the growth medium, Sf21 cells began to express neuronal morphology, or the production of elongated, axon-like processes within 2-3 days. Maximal differentiation occurred when in the presence of 42 μM 20-HE or 10 μM insulin. Effects were maximal on day 2 for 20-E and day 3 for insulin. Insulin was more potent at day 2 for inducing differentiation (EC₅₀ = 247 nM) than 20-HE (EC₅₀ = 13 μM). In combination, 20-HE and insulin produced apparent synergistic effects on differentiation. Caffeine, a central nervous system (CNS) stimulant, inhibited induction of elongated processes by 20-HE and/or insulin. Caffeine was a potent inhibitor of 42 μM 20-HE, with an IC50 of 9 nM, and the inhibition was incomplete, resulting in about one quarter of the differentiated cells remaining, even at high concentrations (up to 1 mM). The ability to induce a neural phenotype simplifies studies with of insect cells, compared to either the use of primary nervous tissue or genetic engineering techniques. The presence of ion channels or receptors in the differentiated cells remains to be determined. If they are present, high throughput screening for new insecticides will be accelerated and made more economical by the utility of this method.Master of Science
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Javed, Muhammad Asif. "Insecticide application studies for whitefly control." Thesis, Imperial College London, 2001. http://hdl.handle.net/10044/1/8662.
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Rajatileka, Shavanthi. "Insecticide resistance mechanisms in Aedes aegypti." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501603.
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Dengue is the most rapidly spreading vector borne disease. In Thailand, the number of dengue cases increased from 46,829 in 2006 to 76,059 by September 2008 (WHO, 2008). Insecticides play a vital role in controlling this disease but the success of control programmes is continually threatened by the emergence and spread of insecticide resistance in the vector population.
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Gordon, Jennifer R. "Insecticide Resistance in the Bed Bug." UKnowledge, 2014. http://uknowledge.uky.edu/entomology_etds/14.
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Populations of Cimex lectularius, the bed bug, have resurged around the world posing significant challenges for pest management professionals and causing physical, economic, and emotional strife. Pyrethroid resistance has been found in the vast majority of populations making pest management more difficult. The objectives of my dissertation research were to document the evolution of resistance to pyrethroid and neonicotinoid combination products (called combination products here) and to a neonicotinoid in the laboratory, to record potential fitness costs to resistance to the combination products, and to compare the efficacy of nine insecticides on six populations. In the laboratory, populations of bed bugs evolve resistance rapidly to a combination product and that resistance translates into cross resistance to another combination product. In a follow up experiment, resistance to a neonicotinoid occurred after three generations of selection. Cross resistance between neonicotinoid and pyrethroid resistance was also found, likely due to a common detoxification mechanism (cytochrome P450 mediated metabolism). Resistance was associated with life history costs in three populations that had been selected with a combination product. Therefore, in the absence of selection pressure, populations of bed bugs should revert towards increasing susceptibility. Two pyrethroid products and three combination products were effective at killing three populations of bed bugs but were relatively ineffective against three other populations. However, the combination product, Transport GHP®, the single action pyrrole product, Phantom SC®, and the single action desiccant, CimeXa®, killed 95 to 100% of all populations investigated over a 14-day exposure. Taken together, results reported in this dissertation suggest that insecticide resistance management may be a useful tool for extending the efficacy of insecticides for control of C. lectularius.
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Kerns, David L., and Tony Tellez. "Tank Mixing New Insecticide Chemistries with a Pyrethroid Insecticide for Control of Lepidopterous Pests in Head Lettuce, 1997." College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/221679.
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Confirm, Success and Proclaim were evaluated for lepidopterous insect control in lettuce with and without the addition of Mustang 1.5EW. Success and Proclaim used alone were highly efficacious toward cabbage looper and Heliothinae and did not appear to benefit greatly from the addition of Mustang. However, Confirm's activity towards Heliothinae was significantly improved by the addition of Mustang. Additionally, on large framed plants where coverage is difficult, Confirm benefitted from the addition of a pyrethroid for control of loopers.
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Troczka, Bartlomiej Jakub. "Ryanodine receptors : next generation of insecticide targets." Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/60069/.
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Ryanodine receptors (RyRs) are calcium channels located on the endo(sarco)plasmic reticulum of muscle cells and neurons. They are the largest ion channels known made up of four monomers, each 565kDa in size. Mammals have 3 different RyR isoforms, encoded by different genes, while insects express only one isoform of the receptor, which is only 46% similar (at the amino acid level) to its mammalian counterpart(s). RyRs function to regulate the release of luminal Ca2+ stores into the cell cytoplasm and play a key role in muscle excitation-contraction coupling (ECC). The plant alkaloid ryanodine, from which the receptor derives its name, has been investigated extensively as a potential pest control agent, but to date no commercial products have been identified. Recently two synthetic insecticides selectively targeting pest RyRs were introduced to the market. These compounds belong to the novel group of insecticides called diamides. In this study two insect ryanodine receptors were isolated sequenced and cloned into suitable expression vectors from economically important pests M. persicae and P. xylostella to identify protein site of interaction for the novel compounds. Both proteins were expressed in HEK 293 cells and Sf9 cells and analysed for evidence of function using ryanodine binding assays and calcium release imaging. In the case of M. persicae RyR the expression level was not sufficient to obtain any functional data. However the expression of P. xylostella RyR showed evidence of function in both HEK and Sf9 cells. Functional studies showed that expressed P. xylostella RyR can bind [3H] ryanodine and respond to various caffeine concentrations; the protein was also sensitive to both diamide compounds. DNA sequencing of RyR from field evolved diamide resistant strains of P. xylostella identified a mutation causing amino acid change G4946E. Functional analysis of modified RyR construct in Sf9 cells showed significantly reduced sensitivity to to both diamide compounds while retaining caffeine and ryanodine sensitivity comparable to the expressed WT form.
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Boone, Michelle D. "Effects of an insecticide on amphibian communities /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9999275.
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Shamu, Shepherd. "The effect of removing tariffs and domestic taxes on insecticide treated nets (ITNs), netting materials and insecticides in Zimbabwe." Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/6952.
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Bibliography: leaves 100-103.The use of Insecticide Treated Nets (ITNs) has already proved to be a cost effective way of malaria vector control. The important emphasis now should therefore be on how to increase the accessibility and utilization of the mosquito nets through devising viable financing and promotional mechanisms that are sustainable and equitable in the long run. One way of financing ITNs that has been propounded by the Roll Back Malaria (REM) has been the issue of the reduction or elimination of tariffs and domestic taxes on ITNs and their inputs. The purpose of this study was to look at how and in what way this RBM financing policy on eliminating tariffs and domestic taxes on ITNS and their inputs would benefit the consumer given the complex nature of ITN industry operations and the consumer behaviour. The study concentrated on information gathered from net manufacturers and insecticide providers, wholesalers and retailers and some key personnel in the overall ITN industry to gather information on production, sales and marketing trends. The analysis revealed that there are indeed gains to be realized by both the consumer and the private sector if tariffs and taxes are removed, in terms of the increase in demand and supply of the product. The elimination of the 15% tariff on ITN input prices in Zimbabwe, ceteris paribus, would lead to the retail price of ITNs falling by between 4% and 12%. This would result in consumer purchases increasing by between 2% and 11%. The elimination of both taxes, other things constant, would lead to the price falling by between 4% and 23 %, leading to retail purchases increasing by between 2% and 21%. Depending on the price elasticities of demand and supply, the fall in retail prices and the consequent increase in retail purchases are quite substantial in a developing country context where incomes are very low. Sensitivity analysis using different demand and supply elasticities also showed that the elimination of tariffs and taxes on ITNs and their inputs would lead to a substantial fall in retail purchases resulting in retail purchases increasing.
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Osman, Abdelgadir Ahmed. "Resistance to pyrethroid and organophosphate insecticides in the pink bollworm, Pectinophora gossypiella (Saunders)." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184760.
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Baseline data on susceptibility levels to azinphosmethyl and permethrin were generated on five field-collected populations of the pink bollworm, Pectinophora gossypiella (Saunders), from Arizona and Southern California, relative to a standard susceptible laboratory strain. The field strains showed less than 2-fold resistance to azinphosmethyl but exhibited variable levels (1.3- to 18.3-fold) of resistance to permethrin. Resistance of pink bollworms to permethrin seems to be correlated with the pattern of insecticide-use prevalent in the localities studied. Strains from Yuma, Phoenix and Westmoreland exhibited highest levels of resistance to permethrin. Synergism of permethrin with an oxidase inhibitor, piperonyl butoxide (PBO), and an esterase inhibitor, S,S,S-tributyl phosphorotrithioate (DEF), produced less than 2-fold synergism in the Yuma strain. Results suggest that nonmetabolic factor(s) may be involved in permethrin resistance of the Yuma field strain since neither PBO nor PBO/DEF combination suppressed resistance completely. It is possible that pink bollworm resistance is at least partially conferred by the khr-gene. Rearing of two field strains collected from Marana and Yuma under insecticide-free conditions resulted in reversion of resistance in four and five generations, respectively, to levels close to that found in the susceptible laboratory strain. Permethrin-resistance in these field strains is unstable and is apparently in its early phase of development. Monitoring of resistance in field strains should be performed preferably in the F₁ generation. Subsequently, selection studies were performed on both larval and adult stages to investigate the capacity of the pink bollworm to develop resistance in both life-stages. Selection of larvae with both azinphosmethyl and permethrin resulted in higher levels of resistance in larvae than in adults. Results suggest that azinphosmethyl possesses a low degree of selectivity for development of resistance in pink bollworm adults. Fourteen to 16 generations of selection with azinphosmethyl and permethrin produced ca. 2- and 9-fold resistance, respectively, in the adult stage. A laboratory-selected strain showing ca. 13-fold resistance was used in reciprocal crosses with a susceptible laboratory strain. The F₁ results suggested that inheritance of permethrin resistance was autosomal and partially dominant. Chi-square analysis of responses of backcross progeny indicated that resistance seems to be conferred by a major gene under the influence of minor gene(s).
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Bret, Brian Louis. "Effects of an insecticide on German cockroach behavior." Diss., This resource online, 1985. http://scholar.lib.vt.edu/theses/available/etd-03042009-040616/.
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Howell, Paul I. "Genetic components of insecticide resistance in Anopheles arabiensis." Thesis, Liverpool School of Tropical Medicine, 2018. http://livrepository.liverpool.ac.uk/3027687/.
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Currently 3.3 billion people are at risk of becoming infected with malaria worldwide with over 90% living in sub-Saharan Africa. Recently it was estimated that approximately 131,000 fewer deaths and over 650,000 cases of malaria were averted during the last 15 years. These changes are attributed to the widespread implementation of long-lasting insecticide-treated nets, indoor residual spraying with insecticides, and artemisinin-combined therapeutics across Africa. However, current challenges have resulted in a stalling of progress with insecticide resistance as the most prominent and potentially dangerous. Although there has been recent interest in insecticide resistance in Anopheles arabiensis, much is still unknown. Compared to the other main vectors, its exophilic nature and more catholic diet results in opportunistic feeding thereby circumventing home-based insecticide-treated interventions. Therefore, the goal of this dissertation is to examine insecticide resistance within the under-studied West Africa to better understand the origin and spread of anthropogenic-associated resistance in An. arabiensis by 1) using quantitative trait loci (QTL) analysis, to determine the genetic basis of dieldrin resistance in An. arabiensis from the Sudan, 2) determine the origin and spread of Gaba-296S in the Sahel region and 3) investigate novel bendiocarb resistance in Senegal using a paired QTL/microarray analysis. Using QTL analysis, a single, strong peak was estimated in both the F2 and advanced intercross line families at a similar position on the 2L chromosomal arm. In neither instance did the peak contain with the Gaba-296S mutation, typically implicated in dieldrin resistance, but was found 4Mb upstream towards the telomere near an ATP-binding cassette (ABCB-4) transporter. Second, an approximately 2kb region of gamma-amino butyric acid (GABA) was sequenced in individuals collected from the wild. In resistant individuals, the same base-pair polymorphisms were seen within 10 bases after the Gaba-296S mutation in samples from Senegal, Burkina Faso, and the Sudan. Based on this, it was concluded that a single origin of Gaba-296S had occurred with a subsequent sweep across the Sahel. This is the first broad geographical spread of resistance alleles through reported for this species. Last I investigated bendiocarb resistance in a population from Rufisque, Senegal. While QTL analysis was inconclusive, microarray analysis found the cuticular protein genes CPLCX2 and CPLCG4 overexpressed in the resistant population. Across West Africa, urbanisation and agriculture have had a major impact on the evolution of resistance in An. arabiensis. This dissertation highlights several important attributes that make An. arabiensis a particularly difficult species to control. My hope is that this body of work will stimulate research into the effects of urbanisation and resistance in An. arabiensis, especially in areas where urban and peri-urban agriculture is present.
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Silva, Martins Walter Fabricio. "Evolutionary genetics of insecticide resistance in Culex quinquefasciatus." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2047820/.
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Culex quinquefasciatus mosquitoes play an important role in the transmission of vector-borne diseases of public health importance including lymphatic filariasis (LF) as well as many arboviruses. Insecticide-based approaches are one of the most important interventions to mitigate disease burden; nevertheless increased resistance of vectors to insecticides imposes a challenge for the sustainability and effectiveness of both current and future vector control interventions. Hence, understanding the dynamics and likely mechanisms underlying the evolution of resistance will be critical to effective decision-making in insecticide resistance management strategies. The present study was set out to investigate the genetic basis of insecticide resistance in C. quinquefasciatus from Uganda. Two objectives were developed, 1) to investigate patterns of insecticide resistance across the south of the country and how this might reflect local selection and genetic structure and 2) to investigate the basis of the molecular mechanisms underlying resistance to all four classes of insecticides recommended for vector control. The population genetic study compared and contrasted microsatellite markers and two resistance-associated loci (Vgsc-1014F and Ace1-119S). While no significant difference in genetic diversity across populations were detected by microsatellites, higher frequency of Vgsc-1014F compared to the Ace1-119S mutations was observed in all populations suggesting that the Ugandan Eastern – Southwest populations are under a heterogeneous selection pressure, which created a pattern of local adaptation in these populations. Additionally, the copy number (CN) assay developed in this study indicated the presence of CN variation in the voltage gated sodium channel (Vgsc) gene in about 10% of the individuals assayed from these populations. Genotypic/phenotypic association tests conducted on bendiocarb resistant-individuals suggested that this resistant phenotype was not underlying solely by the 119S target-site mutation in the Ace-1 gene. Indeed, synergist bioassays show an increase of mortality of around 25% in mosquitoes pre-exposed to either TTP or PBO, indicating a possible resistance mediated by detoxification enzymes. Using a novel whole-transcriptome microarray we profiled the bendiocarb-resistant phenotype and implicated two P450s (Cyp-Cx1 and Cyp6n23) with the highest up-regulation expression compared to a susceptible strain. Remarkably, the predicted Cyp-Cx1 is closely related to two P450s from the family Cyp6, which were already validated in vitro as insecticide metabolizers in A. gambiae and A. aegypti, which corroborates a likely association of metabolic resistance in the investigated bendiocarb-resistant phenotype. Taken together the results yielded by genomic and transcriptomic experiments provide evidence that Ugandan C. quinquefasciatus mosquitoes are under heterogeneous selection pressure imposed by insecticides from distinct classes, and that the evolution of insecticide resistance is mediated by at least two main genetic mechanisms; target-site mutations (Vgsc-1014F and Ace1-119S) as well as over-expression of detoxification enzymes.
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Clark, L. J., and E. W. Carpenter. "Insecticide Evaluation Studies, Safford Agricultural Center, 1999-2000." College of Agriculture, University of Arizona (Tucson, AZ), 2001. http://hdl.handle.net/10150/211302.
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Three studies were conducted over the two year period to explore the effectiveness of using pyrethroid insecticides only vs. rotating insecticide chemistries between the pyrethroids and organophosphates on both long and short staple cotton varieties. These same treatments were also evaluated over Bt and non-Bt varieties. In the worst case scenario, where weather conditions prevented timely application of insecticides and effectiveness of insecticides applied, long staple cotton yielded around 1/3 bale per acre after six insecticide applications. Within 200 feet of this experiment, during the same cropping season, with the same insecticides applied, DP 90B (a Bt variety) produced 3 bales per acre. Details of these studies are contained in this report.
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Umeda, K., D. Stewart, and J. Murrieta. "DPX-MP062 (DuPont) Insecticide Efficacy in Broccoli Study." College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/221603.
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DPX -MP062 (Dupont) insecticide was applied two times in broccoli for cabbage looper (Trichoplusia ni. CL) control and demonstrated efficacy comparable or superior to methomyl (Lannate®) or esfenvalerate (Asana®). DPX-MP062 0.025 to 0.065 lb AI/A alone or in combination with Lannate significantly reduced the number of medium to large sized CL larvae relative to the untreated broccoli following each application.
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McCart, Caroline. "Insecticide resistance in Drosophila melanogaster and Ctenocephalides felis." Thesis, University of Bath, 2006. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439271.
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Chandler, Darren Robert. "Effects of acylurea insecticide in Manduca sexta larvae." Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303547.
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Zimmer, Christoph Thomas [Verfasser], and P. W. [Akademischer Betreuer] Zebitz. "Monitoring, mechanisms and management of insecticide resistance and insecticide mode of action in coleopteran pests of winter oilseed rape with special reference to neonicotinoid insecticides under laboratory and applied aspects / Christoph Thomas Zimmer. Betreuer: P.W. Zebitz." Hohenheim : Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim, 2015. http://d-nb.info/1067485406/34.
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Goindin, Daniella. "Étude des résisatances aux insecticides et des réponses biologiques aux changements climatiques du moustique Aedes aegypti, vecteur de la Denguen du Chikungunya et du Zika en Guadeloupe." Thesis, Antilles, 2016. http://www.theses.fr/2016ANTI0054/document.
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La Guadeloupe fait partie des pays où la Dengue est endémique avec des épidémies tous les 2 à 3 ans. Depuis 3 ans, d'autres arboviroses sont apparues sur le continent américain avec le Chikungunya en 2013 puis le Zika en 2015, causant d'importantes épidémies notamment en Guadeloupe. Le seul vecteur reconnu de ces maladies en Guadeloupe est le moustique Aedes aegypti. Il n'y a pas de vaccin, ni de traitements spécifiques contre ces infections et les moyens de prévention contre ces maladies passent par la surveillance et le contrôle des populations de moustiques sur le terrain. Les méthodes de surveillance sont basées le plus souvent sur l'analyse d'indices larvaires, parfois controversés. De plus, les moyens de contrôle des vecteurs ont longtemps été basés sur l'utilisation massive d'insecticides chimiques entraînant la résistance des moustiques à ces produits. Ce travail de thèse s'est donc articulé autour de deux grands axes devant permettre d'améliorer la prévention et le contrôle de ces arboviroses: i) la recherche d'un nouvel outil de surveillance des populations vectrices, basé sur la physiologie des femelles adultes et ii) l'évaluation des niveaux et l'étude de certains mécanismes de résistance à trois insecticides chimiques, le Téméphos, le Malathion (utilisés dans le passé) et la Deltaméthrine (utilisée actuellement). Un modèle de surveillance des populations vectrices basé sur les taux de parité en lien avec l'espérance de vie des femelles, en fonction des températures a été développé, et des pistes sur les situations entomologiques les plus à risques se sont dessinées. Les épreuves de résistance effectuées sur des larves de moustiques de Guadeloupe ont globalement révélé de forts niveaux de résistance au Téméphos et de faibles niveaux de résistance au Malathion. Les tests adulticides ont mis en évidence une résistance modérée des femelles à la Deltaméthrine. Les investigations moléculaires ont démontré des fréquences alléliques très élevées pour les mutations Kdr V1016I et F1534C connues pour être liées à la résistance aux pyréthrinoïdes. De plus, l'évaluation des niveaux d'expression constitutifs de certains gènes de détoxification a révélé des surexpressions significatives des populations testées par rapport à la souche sensible Bora-Bora, pour la carboxy-choline-estérase CCEAE3A, quatre cytochromes P450 à mono-oxygénases (014614, CYP6M11, CYP6BB2 et CYP9J23) et la glutathione-S-transférase GSTE2Guadeloupe is an endemic country for Dengue with epidemics every 2 to 3 years. In the past 3 years, other arboviruses have reached the Americas with Chikungunya virus in 2013 and Zika virus in 2015, causing major epidemics including in Guadeloupe. The only known vector of these diseases in Guadeloupe is the mosquito Aedes aegypti. As there is no vaccine nor specific treatment against these infections, prevention against these diseases is achieved through the monitoring and control of mosquito populations. Monitoring methods are based mostly on larval indices, with sometimes controversial results. In addition, vector control methods are based since a very long time on the massive use of chemical insecticides, causing mosquito resistance to these products. This work has therefore focused on two main areas to improve the prevention and control of these arboviruses: i) the search of a new vector population monitoring tool, based on the physiology of adult females and ii) the assessment of the resistance levels and mechanisms regarding three chemical insecticides, Temephos, Malathion (used in the past) and Deltamethrin (currently used). A vector population monitoring model based on females life expectancy as a function of parity rates and according to temperatures has being developed, and tracks on the entomological situations most at risk have emerged. Insecticide resistance tests performed on mosquito larvae have generally found strong Temephos resistance levels and low resistance to Malathion. Adulticide tests showed a moderate resistance of females to Deltamethrin. Molecular investigations have shown very high allelic frequencies for kdr mutations V1016I and F1534C, known to be associated with pyrethroid resistance. Moreover, the evaluation of constitutive expression levels of some detoxification genes revealed significant overexpression in tested Aedes aegypti populations compared to the susceptible Bora-Bora strain, for the carboxy-choline-esterase CCEAE3A, four cytochrome P450 mono-oxygenases (014614, CYP6M11, CYP6BB2 and CYP9J23) and the glutathione-S-transferase GSTE2
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Pitti, caballero Javier ernesto. "Nanoencapsulation d’un agent synergisant chimique, la deltaméthrine pour potentialiser l’effet d’un insecticide, l’indoxacarbe contre les insectes nuisibles." Thesis, Angers, 2019. http://www.theses.fr/2019ANGE0005.
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L’utilisation non raisonnée d’insecticides a des conséquences sur l’environnement et la santé humaine mais aussi sur le développement de résistances chez les insectes nuisibles. Dans ce contexte, ce travail de thèse porte sur le développement d'une technique de nanoencapsulation d'un agent synergisant chimique, la deltaméthrine (pyréthrinoide), associé un pro-insecticide l’indoxacarbe (oxadiazine). Sur la base d’études in vitro sur cellules neurosecrétrices de blattes (Periplaneta americana), une action synergique entre la deltaméthrine et le DCJW (métabolite actif de l’indoxacarbe) a été démontrée via un mécanisme intracellulaire original dépendant du calcium. Des études toxicologiques in vivo sur des blattes adultes ont permis de confirmer l’effet synergique entre la deltaméthrine et l’indoxacarbe. Pour optimiser la formulation de l’association de ces composés, des nanocapsules lipidiques contenant la deltaméthrine utilisée comme agent synergisant ont été produites. Les études de toxicité sur blattes ont permis de déterminer les doses effectives les plus faibles de l’association deltaméthrine nanoencapsulée/indoxacarbe et d’obtenir une optimisation de l’effet synergique avec la deltaméthrine nanoencapsulée. Cet effet synergique est plus important que celui du piperonyl butoxyde, composé utilisé dans les formulations d'insecticides classiques. Les résultats indiquent que la deltaméthrine, protégée des estérases par la nanoencapsulation, permet d’optimiser l’efficacité du traitement tout en réduisant les doses d’indoxacarbe. Cette nouvelle stratégie est une première étape dans le développement d'une formulation phytosanitaire efficace contre les insectes nuisiblesThe over-use of pesticides has represented a concern not only for its consequences against the environment but also for the increase in resistance mechanisms in pest insects. In this context, our research project is focused on the development of a nanoencapsulation technique of a deltamethrin (pyrethroid), used as synergistic agent, combined with a pro-insecticide indoxacarb (oxadiazine). Based on in vitro studies performed on cockroach (Periplaneta americana) neurosecretory cells, synergistic effect between deltamethrin and DCJW (active metabolite of indoxacarb) has been characterized, occurring through an original calcium-dependent intracellular mechanism. In vivo toxicological studies on adult cockroaches have confirmed these previous results. To optimize the formulation including the synergistic agent and indoxacarb, lipid nanocapsules (LNCs) containing deltamethrin have been developed. It has been possible to determine the lower effective doses of LNC-deltamethrin/indoxacarb mixture producing the synergistic effect in whole insects. The synergism obtained is more important than that of obtained with piperonil butoxide (PBO), the well-known synergist used in classical insecticide formulations. The results also indicate that LNC-deltamethrin, protected from esterase-induced detoxification enhances the toxicity of indoxacarb while reducing doses. This novel strategy is a first step for the development of a novel formulation more efficient against pest insects
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Amiri, Behnam. "Production and function of destruxins; toxins from Metarhizium spp." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368668.
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Dunning, Rebecca. "Insecticide detoxication in drosophila melanogaster : The role of Cyp6a2." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531811.
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Ladonni, H. "Genetics and biochemistry of insecticide resistance in Anopheles stephensi." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384428.
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Little, E. J. "Insecticide resistance£t in the aphid Myzus persicae (Sulzer)." Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235363.
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French-Constant, R. H. "The ecological genetics of insecticide resistance in Myzus persicae." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/38312.
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Umeda, K., and C. Fredman. "Admire® Insecticide Use and Influence on Cantaloupe Growth." College of Agriculture, University of Arizona (Tucson, AZ), 1995. http://hdl.handle.net/10150/221493.
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Cantaloupe growth was influenced by using imidacloprid (Admire®) insecticide to control, suppress, or reduce whiteflies. The growth rate of cantaloupe was evaluated at regular intervals after crop emergence and a rate response was observed with greater growth with respect to increase in Admire® rate. Following at planting time applications, at 3 and 4 weeks after treatment (WAT) cantaloupe plants had more foliar growth and a greater number of leaves with increasing Admire® rate. At 5 to 8 WAT, cantaloupe vines exhibited greater growth with increasing rates of Admire®.
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Barbosa, Susana. "Mathematical models for exploring insecticide resistance in vector mosquitoes." Thesis, University of Liverpool, 2012. http://livrepository.liverpool.ac.uk/8533/.
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The emergence and spread of insecticide resistance compromises the control of mosquito borne diseases that are responsible for millions of deaths every year in tropical and subtropical areas. Mathematical modelling is a valuable tool that can be used to explore different aspects of the development and management of insecticide resistance. We have used standard population genetics theory and ecological modelling techniques for developing models to evaluate the spread of resistance in the field. We started by developing a methodology to quantify the strength of selection for resistance occurring in nature. We used data from Mexico on the mosquito Aedes aegypti and a maximum likelihood methodology to estimate the selection and dominance coefficients driving the evolution of resistance in the field. We additionally explored the impact of poor data collection, data that combine information from different locations, and the consequences of selection and dominance coefficients varying over the sampling time period. This analysis highlighted factors highly relevant to field work such as the need for frequent surveillance in discrete sentinel sites. The use of insecticidal bed nets represents the primary tool for the prevention of malaria worldwide. It is of extreme importance to maintain their efficacy against mosquitoes, which has been undermined by the development of insecticide resistance. We assed the contribution of a novel design of bed nets in delaying insecticide resistance while at the same time determining the important parameters in driving resistance in an heterogeneous environment. We showed that this new bed net can indeed contribute to the delay of the spread of resistance, but surprisingly could have the reverse effect in specific circumstances. Finally we developed a model for the vector of malaria, that considers the stage-structured nature of the mosquito life cycle and, most importantly, explicitly incorporates insecticide resistance. It can be used to understand the population dynamics of mosquitoes throughout their entire lifecycle while analysing the impact of vector control interventions, alone and in combination, and the spread of insecticide resistance that those interventions induce. We showed that targeting the larval stages has the greatest effect on the adult population followed by targeting non host-seeking female adults. According to our results, low levels of resistance can induce failure of interventions, and the rate of spread of resistance is faster when insecticides target the larval stages.
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Shaikh, Nasir Pasha. "Herbicide and insecticide interactions in peanut (Arachis hypogaea L.)." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0004788.
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Ellsworth, Peter C., Brian Deeter, and Mike Whitlow. "EUP Evaluation of a Novel Insecticide for Lygus Control." College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/197261.
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Lygus became the number one pest of cotton in 1998 with statewide losses of over $16 million in spite of individual costs to the grower of over $55/A for control. Selective technologies for whitefly and pink bollworm control reduce the number of broad spectrum sprays that incidentally control Lygus. Control of Lygus depends mainly on just two related chemical classes of insecticides, organophosphates and carbamates. Over reliance on such a limited diversity of chemical controls increases the risk of resistance. Further, FQPA threatens the future availability of many of our main stay chemical controls. The study reported here sought to investigate the commercial suitability of a new compound, Regent®, for the control of Lygus. This novel mode of action represents one of the few potential new tools under development for Lygus management. Under a federal Emergency Use Permit (EUP), Regent was tested against two standards of Lygus control (Orthene® and Vydate®) and an untreated check. In a test of unusually high Lygus densities, Regent provided excellent control of small (instars 1–3) and large (instars 4–5) Lygus nymphs and may provide marginally better control of adults than current standards. None of the tested agents provided quick control or knockdown of adults. Rather, adult levels were reduced over time, most likely as a result of prevention of the development of new adults via nymphal control. All three materials protected cotton producing yields significantly higher than the check. The Orthene treatment had the highest yield, though not significantly higher than the Regent treatment which was effectively sprayed one less time than the other compounds.
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Dennehy, Timothy J., Benjamin A. DeGain, Virginia S. Harpold, and Robert J. Nichols. "Biotype Designations and Insecticide Susceptibility of Southwestern Bemisia tabaci." College of Agriculture, University of Arizona (Tucson, AZ), 2007. http://hdl.handle.net/10150/198219.
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We report biotype identifications and susceptibility to insecticides of whiteflies (Bemisia tabaci) collected from cotton, vegetables, melons and ornamental plans during the 2005 season. No major problems with field performance of insecticides against whiteflies were confirmed in 2005 in Arizona. Whitefly resistance to pyriproxyfen did not increase, relative to levels recorded in 2004. However, we detected pyriproxyfen resistance in all Arizona whitefly samples tested. A single sample collected from cotton in Holtville, CA, had no detectable resistance to pyriproxyfen. Samples from cotton in Buckeye, Coolidge, Scottsdale, and stanfield, Arizon,a had the highest levels of resistance, with > 31-45% of eggs surviving diagnostic concentration bioassays of 0.1 ug/ml pyriproxyfen. Whitefly susceptibility to buprofezin (Applaud®/Courier®) has not changed significantly since 1997. Resistance to synergized pyrethroids (e.g., Danitol® + Orthene®) has decreased strikingly on a statewide basis since 1995, though unacceptably high frequencies of resistant whiteflies were detected in some 2005 collections from all commodities sampled. Whiteflies collected from Arizona cotton, melons, and vegetables continued to be highly susceptible to imidacloprid (Admire®/Provado®). One whitefly collection from poinsettias in Phoenix (05-39) was substantially less susceptibile to imidacloprid, and the related neonicotinoid insecticides, acetamiprid, and thiamethoxam. Regression analysis yielded a significant correlation between acetamiprid and thiamethoxam. Whiteflies from cotton that were least susceptibile to acetamiprid were also significantly less susceptible to thiamethoxam (Actara®/Centric®/Platinum®). The most worrisome of our 2005 findings was that 6 out of 13 samples of whitefly-infested poinsettias collected from retail stores in metropolitan Tucson and Phoenix consisted of only the Q biotype of Bemisia tabaci. The plants were infested with very low whitefly numbers and thus we were unable to establish them in laboratory cultures and evaluate their resistance status. The Q biotype is native to Spain and was first detected in the US by our group in 2004 on a sample taken from poinsettias. Our concern is that the Q biotype strain we detected in 2004 was highly resistant to a broad range of insecticides used to manage whiteflies in Arizona. None of the 26 field collections evaluated in 2005 was the Q biotype.
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Dennehy, Timothy J., Benjamin A. DeGain, Virginia S. Harpold, and Robert J. Nichols. "Biotype Designations and Insecticide Susceptibility of Southwestern Bemisia tabaci." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008. http://hdl.handle.net/10150/215035.
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We report biotype identifications and susceptibility to insecticides of whiteflies (Bemisia tabaci) collected from cotton, vegetables, melons and ornamental plans during the 2005 season. No major problems with field performance of insecticides against whiteflies were confirmed in 2005 in Arizona. Whitefly resistance to pyriproxyfen did not increase, relative to levels recorded in 2004. However, we detected pyriproxyfen resistance in all Arizona whitefly samples tested. A single sample collected from cotton in Holtville, CA, had no detectable resistance to pyriproxyfen. Samples from cotton in Buckeye, Coolidge, Scottsdale, and Stanfield, Arizona had the highest levels of resistance, with > 31-45% of eggs surviving diagnostic concentration bioassays of 0.1 ug/ml pyriproxyfen. Whitefly susceptibility to buprofezin (Applaud®/Courier®) has not changed significantly since 1997. Resistance to synergized pyrethroids (e.g., Danitol® + Orthene®) has decreased strikingly on a statewide basis since 1995, though unacceptably high frequencies of resistant whiteflies were detected in some 2005 collections from all commodities sampled. Whiteflies collected from Arizona cotton, melons, and vegetables continued to be highly susceptible to imidacloprid (Admire®/Provado®). One whitefly collection from poinsettias in Phoenix (05-39) was substantially less susceptibile to imidacloprid, and the related neonicotinoid insecticides, acetamiprid, and thiamethoxam. Regression analysis yielded a significant correlation for whitefly susceptibility to acetamiprid and thiamethoxam. Whiteflies from cotton that were least susceptibile to acetamiprid were also significantly less susceptible to thiamethoxam (Actara®/Centric®/Platinum®). The most worrisome of our 2005 findings was that 6 out of 13 samples of whitefly-infested poinsettias collected from retail stores in metropolitan Tucson and Phoenix consisted of only the Q biotype of Bemisia tabaci. The plants were infested with very low whitefly numbers and thus we were unable to establish them in laboratory cultures to evaluate their resistance status. The Q biotype is native to Spain and was first detected in the US by our group in 2004 on a sample taken from poinsettias. The Q biotype strain we detected in 2004 was highly resistant to a broad range of insecticides used to manage whiteflies in Arizona. None of the 26 field collections evaluated in 2005 was the Q biotype.
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Flint, H. M., F. D. Wilson, and N. J. Curtice. "Pheromone and Insecticide Treatments of Nectariless and Nataried Varieties." College of Agriculture, University of Arizona (Tucson, AZ), 1986. http://hdl.handle.net/10150/219775.
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The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.The pink bollworm resistant (nectariless) variety 'Deltapine NSL' yielded as much lint as the standard 'Deltapine-61' (nectaried) under treatments of conventional insecticides or gossyplure and yielded significantly more lint in untreated plots.
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Palumbo, John, Clayton Jr Mullis, Francisco Reyes, and Andreas Amaya. "New Insecticide Alternatives for Aphid Management in Head Lettuce." College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/221649.
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Several new insecticide was compared to Admire and Provado combinations for management of aphids in head lettuce in Yuma in two trials conducted in 1998. Foliar applications of Provado, Fulllfill, Aphistar and Acetamiprid appear to provide an alternative method of controlling aphids on lettuce comparable to prophylactic applications of Admire. In addition, at planting and side dress soil applications of thimethoxam provided aphid control comparable to Admire. The prevention of aphid colonization in lettuce heads with the foliar alternatives may depend greatly on the timing and frequency of applications before harvest occurs. Residual activity of the new foliar alternatives ranged from at least 7-14 days. These studies suggest that more than one application of the foliar products will be necessary to adequately suppress aphid contamination in heads. Evaluations of thiamethoxam suggest that it is more mobile in the soil than Admire and may be a candidate for side dress applications for aphid management.
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Barber, Matthew. "Insecticide resistance in the currant-lettuce aphid, Nasonovia ribisnigri." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268378.
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Byrne, Katharine. "Gene flow and insecticide resistance in the mosquito Culex pipiens." Thesis, Queen Mary, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244074.
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Young, Roderick David Ferguson. "The effects of adjuvants on the performance of insecticide sprays." Thesis, University of the West of Scotland, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241644.
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Daly, Gordon Wilson Scarlett. "The development of azadirachtin as a soil-applied, granular insecticide." Thesis, University of Glasgow, 2004. http://theses.gla.ac.uk/1187/.
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The aim of this project was to develop azadirachtin as an insecticide that is applied to the soil, using a granular formulation, for root uptake and subsequent systemic plant protection. A method was developed whereby azadirachtin could be rapidly isolated to approximately 95% purity using flash chromatography. This material was used in all subsequent chemical and biochemical studies. To increase the speed of crude extract analysis, a colorimetric technique was assessed to rapidly quantify azadirachtin. However, this method was generally unsuitable for the requirements of this project because it was non-specific and not stable. Granular formulations based on sodium alginate, starch-kaolin and poly(e-caprolactone), and containing different neem seed extracts were successfully prepared. These granules exhibited differnces in the rate of azadirachtin release into water. Additives such as kaolin clay and rapeseed oil could be used to modify the speed of release. Following application to soil, the position of granules did not affect release rates. However, granule application method was shown to affect the rate at which the limonoid was accumulated within the nasturtium plants. Azadirachtin was shown to be moderately water-soluble (1.29 g/l). During mixing studies between distilled water and n-octanol, the limonoid partitioned more favourably into the non-aqueous phase at a ratio of 7:1. Based on calculated Koc values (<40), azadirachtin was classified as very highly soil mobile. Adsorption occurred principally to the organic matter of soils. Clay minerals were comparably non-sorbent. Desorption from both of these sites occurred readily. Azadirachtin was not persistent within soil where the limonoid’s DT50 was as short as 1.06 days. Initial breakdown resulted in the acetyl moiety being cleaved from the molecule. In addition, azadirachtin was shown to exhibit a pH sensitive hydrolytic degradation. The limonoid’s half-life in solution ranged from 57 days at pH 5 to 7.15 hours at pH 9. In conclusion a suitable granule for a controlled-release of azadirachtin was developed.
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Bass, Chris. "Investigating the molecular mechanisms of insecticide resistance in cat fleas." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408650.
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